| File: | src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Transforms/IPO/GlobalOpt.cpp |
| Warning: | line 2187, column 22 Called C++ object pointer is null |
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| 1 | //===- GlobalOpt.cpp - Optimize Global Variables --------------------------===// | |||
| 2 | // | |||
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | |||
| 4 | // See https://llvm.org/LICENSE.txt for license information. | |||
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | |||
| 6 | // | |||
| 7 | //===----------------------------------------------------------------------===// | |||
| 8 | // | |||
| 9 | // This pass transforms simple global variables that never have their address | |||
| 10 | // taken. If obviously true, it marks read/write globals as constant, deletes | |||
| 11 | // variables only stored to, etc. | |||
| 12 | // | |||
| 13 | //===----------------------------------------------------------------------===// | |||
| 14 | ||||
| 15 | #include "llvm/Transforms/IPO/GlobalOpt.h" | |||
| 16 | #include "llvm/ADT/DenseMap.h" | |||
| 17 | #include "llvm/ADT/STLExtras.h" | |||
| 18 | #include "llvm/ADT/SmallPtrSet.h" | |||
| 19 | #include "llvm/ADT/SmallVector.h" | |||
| 20 | #include "llvm/ADT/Statistic.h" | |||
| 21 | #include "llvm/ADT/Twine.h" | |||
| 22 | #include "llvm/ADT/iterator_range.h" | |||
| 23 | #include "llvm/Analysis/BlockFrequencyInfo.h" | |||
| 24 | #include "llvm/Analysis/ConstantFolding.h" | |||
| 25 | #include "llvm/Analysis/MemoryBuiltins.h" | |||
| 26 | #include "llvm/Analysis/TargetLibraryInfo.h" | |||
| 27 | #include "llvm/Analysis/TargetTransformInfo.h" | |||
| 28 | #include "llvm/BinaryFormat/Dwarf.h" | |||
| 29 | #include "llvm/IR/Attributes.h" | |||
| 30 | #include "llvm/IR/BasicBlock.h" | |||
| 31 | #include "llvm/IR/CallingConv.h" | |||
| 32 | #include "llvm/IR/Constant.h" | |||
| 33 | #include "llvm/IR/Constants.h" | |||
| 34 | #include "llvm/IR/DataLayout.h" | |||
| 35 | #include "llvm/IR/DebugInfoMetadata.h" | |||
| 36 | #include "llvm/IR/DerivedTypes.h" | |||
| 37 | #include "llvm/IR/Dominators.h" | |||
| 38 | #include "llvm/IR/Function.h" | |||
| 39 | #include "llvm/IR/GetElementPtrTypeIterator.h" | |||
| 40 | #include "llvm/IR/GlobalAlias.h" | |||
| 41 | #include "llvm/IR/GlobalValue.h" | |||
| 42 | #include "llvm/IR/GlobalVariable.h" | |||
| 43 | #include "llvm/IR/IRBuilder.h" | |||
| 44 | #include "llvm/IR/InstrTypes.h" | |||
| 45 | #include "llvm/IR/Instruction.h" | |||
| 46 | #include "llvm/IR/Instructions.h" | |||
| 47 | #include "llvm/IR/IntrinsicInst.h" | |||
| 48 | #include "llvm/IR/Module.h" | |||
| 49 | #include "llvm/IR/Operator.h" | |||
| 50 | #include "llvm/IR/Type.h" | |||
| 51 | #include "llvm/IR/Use.h" | |||
| 52 | #include "llvm/IR/User.h" | |||
| 53 | #include "llvm/IR/Value.h" | |||
| 54 | #include "llvm/IR/ValueHandle.h" | |||
| 55 | #include "llvm/InitializePasses.h" | |||
| 56 | #include "llvm/Pass.h" | |||
| 57 | #include "llvm/Support/AtomicOrdering.h" | |||
| 58 | #include "llvm/Support/Casting.h" | |||
| 59 | #include "llvm/Support/CommandLine.h" | |||
| 60 | #include "llvm/Support/Debug.h" | |||
| 61 | #include "llvm/Support/ErrorHandling.h" | |||
| 62 | #include "llvm/Support/MathExtras.h" | |||
| 63 | #include "llvm/Support/raw_ostream.h" | |||
| 64 | #include "llvm/Transforms/IPO.h" | |||
| 65 | #include "llvm/Transforms/Utils/CtorUtils.h" | |||
| 66 | #include "llvm/Transforms/Utils/Evaluator.h" | |||
| 67 | #include "llvm/Transforms/Utils/GlobalStatus.h" | |||
| 68 | #include "llvm/Transforms/Utils/Local.h" | |||
| 69 | #include <cassert> | |||
| 70 | #include <cstdint> | |||
| 71 | #include <utility> | |||
| 72 | #include <vector> | |||
| 73 | ||||
| 74 | using namespace llvm; | |||
| 75 | ||||
| 76 | #define DEBUG_TYPE"globalopt" "globalopt" | |||
| 77 | ||||
| 78 | STATISTIC(NumMarked , "Number of globals marked constant")static llvm::Statistic NumMarked = {"globalopt", "NumMarked", "Number of globals marked constant"}; | |||
| 79 | STATISTIC(NumUnnamed , "Number of globals marked unnamed_addr")static llvm::Statistic NumUnnamed = {"globalopt", "NumUnnamed" , "Number of globals marked unnamed_addr"}; | |||
| 80 | STATISTIC(NumSRA , "Number of aggregate globals broken into scalars")static llvm::Statistic NumSRA = {"globalopt", "NumSRA", "Number of aggregate globals broken into scalars" }; | |||
| 81 | STATISTIC(NumSubstitute,"Number of globals with initializers stored into them")static llvm::Statistic NumSubstitute = {"globalopt", "NumSubstitute" , "Number of globals with initializers stored into them"}; | |||
| 82 | STATISTIC(NumDeleted , "Number of globals deleted")static llvm::Statistic NumDeleted = {"globalopt", "NumDeleted" , "Number of globals deleted"}; | |||
| 83 | STATISTIC(NumGlobUses , "Number of global uses devirtualized")static llvm::Statistic NumGlobUses = {"globalopt", "NumGlobUses" , "Number of global uses devirtualized"}; | |||
| 84 | STATISTIC(NumLocalized , "Number of globals localized")static llvm::Statistic NumLocalized = {"globalopt", "NumLocalized" , "Number of globals localized"}; | |||
| 85 | STATISTIC(NumShrunkToBool , "Number of global vars shrunk to booleans")static llvm::Statistic NumShrunkToBool = {"globalopt", "NumShrunkToBool" , "Number of global vars shrunk to booleans"}; | |||
| 86 | STATISTIC(NumFastCallFns , "Number of functions converted to fastcc")static llvm::Statistic NumFastCallFns = {"globalopt", "NumFastCallFns" , "Number of functions converted to fastcc"}; | |||
| 87 | STATISTIC(NumCtorsEvaluated, "Number of static ctors evaluated")static llvm::Statistic NumCtorsEvaluated = {"globalopt", "NumCtorsEvaluated" , "Number of static ctors evaluated"}; | |||
| 88 | STATISTIC(NumNestRemoved , "Number of nest attributes removed")static llvm::Statistic NumNestRemoved = {"globalopt", "NumNestRemoved" , "Number of nest attributes removed"}; | |||
| 89 | STATISTIC(NumAliasesResolved, "Number of global aliases resolved")static llvm::Statistic NumAliasesResolved = {"globalopt", "NumAliasesResolved" , "Number of global aliases resolved"}; | |||
| 90 | STATISTIC(NumAliasesRemoved, "Number of global aliases eliminated")static llvm::Statistic NumAliasesRemoved = {"globalopt", "NumAliasesRemoved" , "Number of global aliases eliminated"}; | |||
| 91 | STATISTIC(NumCXXDtorsRemoved, "Number of global C++ destructors removed")static llvm::Statistic NumCXXDtorsRemoved = {"globalopt", "NumCXXDtorsRemoved" , "Number of global C++ destructors removed"}; | |||
| 92 | STATISTIC(NumInternalFunc, "Number of internal functions")static llvm::Statistic NumInternalFunc = {"globalopt", "NumInternalFunc" , "Number of internal functions"}; | |||
| 93 | STATISTIC(NumColdCC, "Number of functions marked coldcc")static llvm::Statistic NumColdCC = {"globalopt", "NumColdCC", "Number of functions marked coldcc"}; | |||
| 94 | ||||
| 95 | static cl::opt<bool> | |||
| 96 | EnableColdCCStressTest("enable-coldcc-stress-test", | |||
| 97 | cl::desc("Enable stress test of coldcc by adding " | |||
| 98 | "calling conv to all internal functions."), | |||
| 99 | cl::init(false), cl::Hidden); | |||
| 100 | ||||
| 101 | static cl::opt<int> ColdCCRelFreq( | |||
| 102 | "coldcc-rel-freq", cl::Hidden, cl::init(2), cl::ZeroOrMore, | |||
| 103 | cl::desc( | |||
| 104 | "Maximum block frequency, expressed as a percentage of caller's " | |||
| 105 | "entry frequency, for a call site to be considered cold for enabling" | |||
| 106 | "coldcc")); | |||
| 107 | ||||
| 108 | /// Is this global variable possibly used by a leak checker as a root? If so, | |||
| 109 | /// we might not really want to eliminate the stores to it. | |||
| 110 | static bool isLeakCheckerRoot(GlobalVariable *GV) { | |||
| 111 | // A global variable is a root if it is a pointer, or could plausibly contain | |||
| 112 | // a pointer. There are two challenges; one is that we could have a struct | |||
| 113 | // the has an inner member which is a pointer. We recurse through the type to | |||
| 114 | // detect these (up to a point). The other is that we may actually be a union | |||
| 115 | // of a pointer and another type, and so our LLVM type is an integer which | |||
| 116 | // gets converted into a pointer, or our type is an [i8 x #] with a pointer | |||
| 117 | // potentially contained here. | |||
| 118 | ||||
| 119 | if (GV->hasPrivateLinkage()) | |||
| 120 | return false; | |||
| 121 | ||||
| 122 | SmallVector<Type *, 4> Types; | |||
| 123 | Types.push_back(GV->getValueType()); | |||
| 124 | ||||
| 125 | unsigned Limit = 20; | |||
| 126 | do { | |||
| 127 | Type *Ty = Types.pop_back_val(); | |||
| 128 | switch (Ty->getTypeID()) { | |||
| 129 | default: break; | |||
| 130 | case Type::PointerTyID: | |||
| 131 | return true; | |||
| 132 | case Type::FixedVectorTyID: | |||
| 133 | case Type::ScalableVectorTyID: | |||
| 134 | if (cast<VectorType>(Ty)->getElementType()->isPointerTy()) | |||
| 135 | return true; | |||
| 136 | break; | |||
| 137 | case Type::ArrayTyID: | |||
| 138 | Types.push_back(cast<ArrayType>(Ty)->getElementType()); | |||
| 139 | break; | |||
| 140 | case Type::StructTyID: { | |||
| 141 | StructType *STy = cast<StructType>(Ty); | |||
| 142 | if (STy->isOpaque()) return true; | |||
| 143 | for (StructType::element_iterator I = STy->element_begin(), | |||
| 144 | E = STy->element_end(); I != E; ++I) { | |||
| 145 | Type *InnerTy = *I; | |||
| 146 | if (isa<PointerType>(InnerTy)) return true; | |||
| 147 | if (isa<StructType>(InnerTy) || isa<ArrayType>(InnerTy) || | |||
| 148 | isa<VectorType>(InnerTy)) | |||
| 149 | Types.push_back(InnerTy); | |||
| 150 | } | |||
| 151 | break; | |||
| 152 | } | |||
| 153 | } | |||
| 154 | if (--Limit == 0) return true; | |||
| 155 | } while (!Types.empty()); | |||
| 156 | return false; | |||
| 157 | } | |||
| 158 | ||||
| 159 | /// Given a value that is stored to a global but never read, determine whether | |||
| 160 | /// it's safe to remove the store and the chain of computation that feeds the | |||
| 161 | /// store. | |||
| 162 | static bool IsSafeComputationToRemove( | |||
| 163 | Value *V, function_ref<TargetLibraryInfo &(Function &)> GetTLI) { | |||
| 164 | do { | |||
| 165 | if (isa<Constant>(V)) | |||
| 166 | return true; | |||
| 167 | if (!V->hasOneUse()) | |||
| 168 | return false; | |||
| 169 | if (isa<LoadInst>(V) || isa<InvokeInst>(V) || isa<Argument>(V) || | |||
| 170 | isa<GlobalValue>(V)) | |||
| 171 | return false; | |||
| 172 | if (isAllocationFn(V, GetTLI)) | |||
| 173 | return true; | |||
| 174 | ||||
| 175 | Instruction *I = cast<Instruction>(V); | |||
| 176 | if (I->mayHaveSideEffects()) | |||
| 177 | return false; | |||
| 178 | if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) { | |||
| 179 | if (!GEP->hasAllConstantIndices()) | |||
| 180 | return false; | |||
| 181 | } else if (I->getNumOperands() != 1) { | |||
| 182 | return false; | |||
| 183 | } | |||
| 184 | ||||
| 185 | V = I->getOperand(0); | |||
| 186 | } while (true); | |||
| 187 | } | |||
| 188 | ||||
| 189 | /// This GV is a pointer root. Loop over all users of the global and clean up | |||
| 190 | /// any that obviously don't assign the global a value that isn't dynamically | |||
| 191 | /// allocated. | |||
| 192 | static bool | |||
| 193 | CleanupPointerRootUsers(GlobalVariable *GV, | |||
| 194 | function_ref<TargetLibraryInfo &(Function &)> GetTLI) { | |||
| 195 | // A brief explanation of leak checkers. The goal is to find bugs where | |||
| 196 | // pointers are forgotten, causing an accumulating growth in memory | |||
| 197 | // usage over time. The common strategy for leak checkers is to explicitly | |||
| 198 | // allow the memory pointed to by globals at exit. This is popular because it | |||
| 199 | // also solves another problem where the main thread of a C++ program may shut | |||
| 200 | // down before other threads that are still expecting to use those globals. To | |||
| 201 | // handle that case, we expect the program may create a singleton and never | |||
| 202 | // destroy it. | |||
| 203 | ||||
| 204 | bool Changed = false; | |||
| 205 | ||||
| 206 | // If Dead[n].first is the only use of a malloc result, we can delete its | |||
| 207 | // chain of computation and the store to the global in Dead[n].second. | |||
| 208 | SmallVector<std::pair<Instruction *, Instruction *>, 32> Dead; | |||
| 209 | ||||
| 210 | // Constants can't be pointers to dynamically allocated memory. | |||
| 211 | for (Value::user_iterator UI = GV->user_begin(), E = GV->user_end(); | |||
| 212 | UI != E;) { | |||
| 213 | User *U = *UI++; | |||
| 214 | if (StoreInst *SI = dyn_cast<StoreInst>(U)) { | |||
| 215 | Value *V = SI->getValueOperand(); | |||
| 216 | if (isa<Constant>(V)) { | |||
| 217 | Changed = true; | |||
| 218 | SI->eraseFromParent(); | |||
| 219 | } else if (Instruction *I = dyn_cast<Instruction>(V)) { | |||
| 220 | if (I->hasOneUse()) | |||
| 221 | Dead.push_back(std::make_pair(I, SI)); | |||
| 222 | } | |||
| 223 | } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(U)) { | |||
| 224 | if (isa<Constant>(MSI->getValue())) { | |||
| 225 | Changed = true; | |||
| 226 | MSI->eraseFromParent(); | |||
| 227 | } else if (Instruction *I = dyn_cast<Instruction>(MSI->getValue())) { | |||
| 228 | if (I->hasOneUse()) | |||
| 229 | Dead.push_back(std::make_pair(I, MSI)); | |||
| 230 | } | |||
| 231 | } else if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(U)) { | |||
| 232 | GlobalVariable *MemSrc = dyn_cast<GlobalVariable>(MTI->getSource()); | |||
| 233 | if (MemSrc && MemSrc->isConstant()) { | |||
| 234 | Changed = true; | |||
| 235 | MTI->eraseFromParent(); | |||
| 236 | } else if (Instruction *I = dyn_cast<Instruction>(MemSrc)) { | |||
| 237 | if (I->hasOneUse()) | |||
| 238 | Dead.push_back(std::make_pair(I, MTI)); | |||
| 239 | } | |||
| 240 | } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) { | |||
| 241 | if (CE->use_empty()) { | |||
| 242 | CE->destroyConstant(); | |||
| 243 | Changed = true; | |||
| 244 | } | |||
| 245 | } else if (Constant *C = dyn_cast<Constant>(U)) { | |||
| 246 | if (isSafeToDestroyConstant(C)) { | |||
| 247 | C->destroyConstant(); | |||
| 248 | // This could have invalidated UI, start over from scratch. | |||
| 249 | Dead.clear(); | |||
| 250 | CleanupPointerRootUsers(GV, GetTLI); | |||
| 251 | return true; | |||
| 252 | } | |||
| 253 | } | |||
| 254 | } | |||
| 255 | ||||
| 256 | for (int i = 0, e = Dead.size(); i != e; ++i) { | |||
| 257 | if (IsSafeComputationToRemove(Dead[i].first, GetTLI)) { | |||
| 258 | Dead[i].second->eraseFromParent(); | |||
| 259 | Instruction *I = Dead[i].first; | |||
| 260 | do { | |||
| 261 | if (isAllocationFn(I, GetTLI)) | |||
| 262 | break; | |||
| 263 | Instruction *J = dyn_cast<Instruction>(I->getOperand(0)); | |||
| 264 | if (!J) | |||
| 265 | break; | |||
| 266 | I->eraseFromParent(); | |||
| 267 | I = J; | |||
| 268 | } while (true); | |||
| 269 | I->eraseFromParent(); | |||
| 270 | Changed = true; | |||
| 271 | } | |||
| 272 | } | |||
| 273 | ||||
| 274 | return Changed; | |||
| 275 | } | |||
| 276 | ||||
| 277 | /// We just marked GV constant. Loop over all users of the global, cleaning up | |||
| 278 | /// the obvious ones. This is largely just a quick scan over the use list to | |||
| 279 | /// clean up the easy and obvious cruft. This returns true if it made a change. | |||
| 280 | static bool CleanupConstantGlobalUsers( | |||
| 281 | Value *V, Constant *Init, const DataLayout &DL, | |||
| 282 | function_ref<TargetLibraryInfo &(Function &)> GetTLI) { | |||
| 283 | bool Changed = false; | |||
| 284 | // Note that we need to use a weak value handle for the worklist items. When | |||
| 285 | // we delete a constant array, we may also be holding pointer to one of its | |||
| 286 | // elements (or an element of one of its elements if we're dealing with an | |||
| 287 | // array of arrays) in the worklist. | |||
| 288 | SmallVector<WeakTrackingVH, 8> WorkList(V->users()); | |||
| 289 | while (!WorkList.empty()) { | |||
| 290 | Value *UV = WorkList.pop_back_val(); | |||
| 291 | if (!UV) | |||
| 292 | continue; | |||
| 293 | ||||
| 294 | User *U = cast<User>(UV); | |||
| 295 | ||||
| 296 | if (LoadInst *LI = dyn_cast<LoadInst>(U)) { | |||
| 297 | if (Init) { | |||
| 298 | if (auto *Casted = | |||
| 299 | ConstantFoldLoadThroughBitcast(Init, LI->getType(), DL)) { | |||
| 300 | // Replace the load with the initializer. | |||
| 301 | LI->replaceAllUsesWith(Casted); | |||
| 302 | LI->eraseFromParent(); | |||
| 303 | Changed = true; | |||
| 304 | } | |||
| 305 | } | |||
| 306 | } else if (StoreInst *SI = dyn_cast<StoreInst>(U)) { | |||
| 307 | // Store must be unreachable or storing Init into the global. | |||
| 308 | SI->eraseFromParent(); | |||
| 309 | Changed = true; | |||
| 310 | } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) { | |||
| 311 | if (CE->getOpcode() == Instruction::GetElementPtr) { | |||
| 312 | Constant *SubInit = nullptr; | |||
| 313 | if (Init) | |||
| 314 | SubInit = ConstantFoldLoadThroughGEPConstantExpr( | |||
| 315 | Init, CE, V->getType()->getPointerElementType(), DL); | |||
| 316 | Changed |= CleanupConstantGlobalUsers(CE, SubInit, DL, GetTLI); | |||
| 317 | } else if ((CE->getOpcode() == Instruction::BitCast && | |||
| 318 | CE->getType()->isPointerTy()) || | |||
| 319 | CE->getOpcode() == Instruction::AddrSpaceCast) { | |||
| 320 | // Pointer cast, delete any stores and memsets to the global. | |||
| 321 | Changed |= CleanupConstantGlobalUsers(CE, nullptr, DL, GetTLI); | |||
| 322 | } | |||
| 323 | ||||
| 324 | if (CE->use_empty()) { | |||
| 325 | CE->destroyConstant(); | |||
| 326 | Changed = true; | |||
| 327 | } | |||
| 328 | } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) { | |||
| 329 | // Do not transform "gepinst (gep constexpr (GV))" here, because forming | |||
| 330 | // "gepconstexpr (gep constexpr (GV))" will cause the two gep's to fold | |||
| 331 | // and will invalidate our notion of what Init is. | |||
| 332 | Constant *SubInit = nullptr; | |||
| 333 | if (!isa<ConstantExpr>(GEP->getOperand(0))) { | |||
| 334 | ConstantExpr *CE = dyn_cast_or_null<ConstantExpr>( | |||
| 335 | ConstantFoldInstruction(GEP, DL, &GetTLI(*GEP->getFunction()))); | |||
| 336 | if (Init && CE && CE->getOpcode() == Instruction::GetElementPtr) | |||
| 337 | SubInit = ConstantFoldLoadThroughGEPConstantExpr( | |||
| 338 | Init, CE, V->getType()->getPointerElementType(), DL); | |||
| 339 | ||||
| 340 | // If the initializer is an all-null value and we have an inbounds GEP, | |||
| 341 | // we already know what the result of any load from that GEP is. | |||
| 342 | // TODO: Handle splats. | |||
| 343 | if (Init && isa<ConstantAggregateZero>(Init) && GEP->isInBounds()) | |||
| 344 | SubInit = Constant::getNullValue(GEP->getResultElementType()); | |||
| 345 | } | |||
| 346 | Changed |= CleanupConstantGlobalUsers(GEP, SubInit, DL, GetTLI); | |||
| 347 | ||||
| 348 | if (GEP->use_empty()) { | |||
| 349 | GEP->eraseFromParent(); | |||
| 350 | Changed = true; | |||
| 351 | } | |||
| 352 | } else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(U)) { // memset/cpy/mv | |||
| 353 | if (MI->getRawDest() == V) { | |||
| 354 | MI->eraseFromParent(); | |||
| 355 | Changed = true; | |||
| 356 | } | |||
| 357 | ||||
| 358 | } else if (Constant *C = dyn_cast<Constant>(U)) { | |||
| 359 | // If we have a chain of dead constantexprs or other things dangling from | |||
| 360 | // us, and if they are all dead, nuke them without remorse. | |||
| 361 | if (isSafeToDestroyConstant(C)) { | |||
| 362 | C->destroyConstant(); | |||
| 363 | CleanupConstantGlobalUsers(V, Init, DL, GetTLI); | |||
| 364 | return true; | |||
| 365 | } | |||
| 366 | } | |||
| 367 | } | |||
| 368 | return Changed; | |||
| 369 | } | |||
| 370 | ||||
| 371 | static bool isSafeSROAElementUse(Value *V); | |||
| 372 | ||||
| 373 | /// Return true if the specified GEP is a safe user of a derived | |||
| 374 | /// expression from a global that we want to SROA. | |||
| 375 | static bool isSafeSROAGEP(User *U) { | |||
| 376 | // Check to see if this ConstantExpr GEP is SRA'able. In particular, we | |||
| 377 | // don't like < 3 operand CE's, and we don't like non-constant integer | |||
| 378 | // indices. This enforces that all uses are 'gep GV, 0, C, ...' for some | |||
| 379 | // value of C. | |||
| 380 | if (U->getNumOperands() < 3 || !isa<Constant>(U->getOperand(1)) || | |||
| 381 | !cast<Constant>(U->getOperand(1))->isNullValue()) | |||
| 382 | return false; | |||
| 383 | ||||
| 384 | gep_type_iterator GEPI = gep_type_begin(U), E = gep_type_end(U); | |||
| 385 | ++GEPI; // Skip over the pointer index. | |||
| 386 | ||||
| 387 | // For all other level we require that the indices are constant and inrange. | |||
| 388 | // In particular, consider: A[0][i]. We cannot know that the user isn't doing | |||
| 389 | // invalid things like allowing i to index an out-of-range subscript that | |||
| 390 | // accesses A[1]. This can also happen between different members of a struct | |||
| 391 | // in llvm IR. | |||
| 392 | for (; GEPI != E; ++GEPI) { | |||
| 393 | if (GEPI.isStruct()) | |||
| 394 | continue; | |||
| 395 | ||||
| 396 | ConstantInt *IdxVal = dyn_cast<ConstantInt>(GEPI.getOperand()); | |||
| 397 | if (!IdxVal || (GEPI.isBoundedSequential() && | |||
| 398 | IdxVal->getZExtValue() >= GEPI.getSequentialNumElements())) | |||
| 399 | return false; | |||
| 400 | } | |||
| 401 | ||||
| 402 | return llvm::all_of(U->users(), | |||
| 403 | [](User *UU) { return isSafeSROAElementUse(UU); }); | |||
| 404 | } | |||
| 405 | ||||
| 406 | /// Return true if the specified instruction is a safe user of a derived | |||
| 407 | /// expression from a global that we want to SROA. | |||
| 408 | static bool isSafeSROAElementUse(Value *V) { | |||
| 409 | // We might have a dead and dangling constant hanging off of here. | |||
| 410 | if (Constant *C = dyn_cast<Constant>(V)) | |||
| 411 | return isSafeToDestroyConstant(C); | |||
| 412 | ||||
| 413 | Instruction *I = dyn_cast<Instruction>(V); | |||
| 414 | if (!I) return false; | |||
| 415 | ||||
| 416 | // Loads are ok. | |||
| 417 | if (isa<LoadInst>(I)) return true; | |||
| 418 | ||||
| 419 | // Stores *to* the pointer are ok. | |||
| 420 | if (StoreInst *SI = dyn_cast<StoreInst>(I)) | |||
| 421 | return SI->getOperand(0) != V; | |||
| 422 | ||||
| 423 | // Otherwise, it must be a GEP. Check it and its users are safe to SRA. | |||
| 424 | return isa<GetElementPtrInst>(I) && isSafeSROAGEP(I); | |||
| 425 | } | |||
| 426 | ||||
| 427 | /// Look at all uses of the global and decide whether it is safe for us to | |||
| 428 | /// perform this transformation. | |||
| 429 | static bool GlobalUsersSafeToSRA(GlobalValue *GV) { | |||
| 430 | for (User *U : GV->users()) { | |||
| 431 | // The user of the global must be a GEP Inst or a ConstantExpr GEP. | |||
| 432 | if (!isa<GetElementPtrInst>(U) && | |||
| 433 | (!isa<ConstantExpr>(U) || | |||
| 434 | cast<ConstantExpr>(U)->getOpcode() != Instruction::GetElementPtr)) | |||
| 435 | return false; | |||
| 436 | ||||
| 437 | // Check the gep and it's users are safe to SRA | |||
| 438 | if (!isSafeSROAGEP(U)) | |||
| 439 | return false; | |||
| 440 | } | |||
| 441 | ||||
| 442 | return true; | |||
| 443 | } | |||
| 444 | ||||
| 445 | static bool IsSRASequential(Type *T) { | |||
| 446 | return isa<ArrayType>(T) || isa<VectorType>(T); | |||
| 447 | } | |||
| 448 | static uint64_t GetSRASequentialNumElements(Type *T) { | |||
| 449 | if (ArrayType *AT = dyn_cast<ArrayType>(T)) | |||
| 450 | return AT->getNumElements(); | |||
| 451 | return cast<FixedVectorType>(T)->getNumElements(); | |||
| 452 | } | |||
| 453 | static Type *GetSRASequentialElementType(Type *T) { | |||
| 454 | if (ArrayType *AT = dyn_cast<ArrayType>(T)) | |||
| 455 | return AT->getElementType(); | |||
| 456 | return cast<VectorType>(T)->getElementType(); | |||
| 457 | } | |||
| 458 | static bool CanDoGlobalSRA(GlobalVariable *GV) { | |||
| 459 | Constant *Init = GV->getInitializer(); | |||
| 460 | ||||
| 461 | if (isa<StructType>(Init->getType())) { | |||
| 462 | // nothing to check | |||
| 463 | } else if (IsSRASequential(Init->getType())) { | |||
| 464 | if (GetSRASequentialNumElements(Init->getType()) > 16 && | |||
| 465 | GV->hasNUsesOrMore(16)) | |||
| 466 | return false; // It's not worth it. | |||
| 467 | } else | |||
| 468 | return false; | |||
| 469 | ||||
| 470 | return GlobalUsersSafeToSRA(GV); | |||
| 471 | } | |||
| 472 | ||||
| 473 | /// Copy over the debug info for a variable to its SRA replacements. | |||
| 474 | static void transferSRADebugInfo(GlobalVariable *GV, GlobalVariable *NGV, | |||
| 475 | uint64_t FragmentOffsetInBits, | |||
| 476 | uint64_t FragmentSizeInBits, | |||
| 477 | uint64_t VarSize) { | |||
| 478 | SmallVector<DIGlobalVariableExpression *, 1> GVs; | |||
| 479 | GV->getDebugInfo(GVs); | |||
| 480 | for (auto *GVE : GVs) { | |||
| 481 | DIVariable *Var = GVE->getVariable(); | |||
| 482 | DIExpression *Expr = GVE->getExpression(); | |||
| 483 | // If the FragmentSize is smaller than the variable, | |||
| 484 | // emit a fragment expression. | |||
| 485 | if (FragmentSizeInBits < VarSize) { | |||
| 486 | if (auto E = DIExpression::createFragmentExpression( | |||
| 487 | Expr, FragmentOffsetInBits, FragmentSizeInBits)) | |||
| 488 | Expr = *E; | |||
| 489 | else | |||
| 490 | return; | |||
| 491 | } | |||
| 492 | auto *NGVE = DIGlobalVariableExpression::get(GVE->getContext(), Var, Expr); | |||
| 493 | NGV->addDebugInfo(NGVE); | |||
| 494 | } | |||
| 495 | } | |||
| 496 | ||||
| 497 | /// Perform scalar replacement of aggregates on the specified global variable. | |||
| 498 | /// This opens the door for other optimizations by exposing the behavior of the | |||
| 499 | /// program in a more fine-grained way. We have determined that this | |||
| 500 | /// transformation is safe already. We return the first global variable we | |||
| 501 | /// insert so that the caller can reprocess it. | |||
| 502 | static GlobalVariable *SRAGlobal(GlobalVariable *GV, const DataLayout &DL) { | |||
| 503 | // Make sure this global only has simple uses that we can SRA. | |||
| 504 | if (!CanDoGlobalSRA(GV)) | |||
| 505 | return nullptr; | |||
| 506 | ||||
| 507 | assert(GV->hasLocalLinkage())((void)0); | |||
| 508 | Constant *Init = GV->getInitializer(); | |||
| 509 | Type *Ty = Init->getType(); | |||
| 510 | uint64_t VarSize = DL.getTypeSizeInBits(Ty); | |||
| 511 | ||||
| 512 | std::map<unsigned, GlobalVariable *> NewGlobals; | |||
| 513 | ||||
| 514 | // Get the alignment of the global, either explicit or target-specific. | |||
| 515 | Align StartAlignment = | |||
| 516 | DL.getValueOrABITypeAlignment(GV->getAlign(), GV->getType()); | |||
| 517 | ||||
| 518 | // Loop over all users and create replacement variables for used aggregate | |||
| 519 | // elements. | |||
| 520 | for (User *GEP : GV->users()) { | |||
| 521 | assert(((isa<ConstantExpr>(GEP) && cast<ConstantExpr>(GEP)->getOpcode() ==((void)0) | |||
| 522 | Instruction::GetElementPtr) ||((void)0) | |||
| 523 | isa<GetElementPtrInst>(GEP)) &&((void)0) | |||
| 524 | "NonGEP CE's are not SRAable!")((void)0); | |||
| 525 | ||||
| 526 | // Ignore the 1th operand, which has to be zero or else the program is quite | |||
| 527 | // broken (undefined). Get the 2nd operand, which is the structure or array | |||
| 528 | // index. | |||
| 529 | unsigned ElementIdx = cast<ConstantInt>(GEP->getOperand(2))->getZExtValue(); | |||
| 530 | if (NewGlobals.count(ElementIdx) == 1) | |||
| 531 | continue; // we`ve already created replacement variable | |||
| 532 | assert(NewGlobals.count(ElementIdx) == 0)((void)0); | |||
| 533 | ||||
| 534 | Type *ElTy = nullptr; | |||
| 535 | if (StructType *STy = dyn_cast<StructType>(Ty)) | |||
| 536 | ElTy = STy->getElementType(ElementIdx); | |||
| 537 | else | |||
| 538 | ElTy = GetSRASequentialElementType(Ty); | |||
| 539 | assert(ElTy)((void)0); | |||
| 540 | ||||
| 541 | Constant *In = Init->getAggregateElement(ElementIdx); | |||
| 542 | assert(In && "Couldn't get element of initializer?")((void)0); | |||
| 543 | ||||
| 544 | GlobalVariable *NGV = new GlobalVariable( | |||
| 545 | ElTy, false, GlobalVariable::InternalLinkage, In, | |||
| 546 | GV->getName() + "." + Twine(ElementIdx), GV->getThreadLocalMode(), | |||
| 547 | GV->getType()->getAddressSpace()); | |||
| 548 | NGV->setExternallyInitialized(GV->isExternallyInitialized()); | |||
| 549 | NGV->copyAttributesFrom(GV); | |||
| 550 | NewGlobals.insert(std::make_pair(ElementIdx, NGV)); | |||
| 551 | ||||
| 552 | if (StructType *STy = dyn_cast<StructType>(Ty)) { | |||
| 553 | const StructLayout &Layout = *DL.getStructLayout(STy); | |||
| 554 | ||||
| 555 | // Calculate the known alignment of the field. If the original aggregate | |||
| 556 | // had 256 byte alignment for example, something might depend on that: | |||
| 557 | // propagate info to each field. | |||
| 558 | uint64_t FieldOffset = Layout.getElementOffset(ElementIdx); | |||
| 559 | Align NewAlign = commonAlignment(StartAlignment, FieldOffset); | |||
| 560 | if (NewAlign > DL.getABITypeAlign(STy->getElementType(ElementIdx))) | |||
| 561 | NGV->setAlignment(NewAlign); | |||
| 562 | ||||
| 563 | // Copy over the debug info for the variable. | |||
| 564 | uint64_t Size = DL.getTypeAllocSizeInBits(NGV->getValueType()); | |||
| 565 | uint64_t FragmentOffsetInBits = Layout.getElementOffsetInBits(ElementIdx); | |||
| 566 | transferSRADebugInfo(GV, NGV, FragmentOffsetInBits, Size, VarSize); | |||
| 567 | } else { | |||
| 568 | uint64_t EltSize = DL.getTypeAllocSize(ElTy); | |||
| 569 | Align EltAlign = DL.getABITypeAlign(ElTy); | |||
| 570 | uint64_t FragmentSizeInBits = DL.getTypeAllocSizeInBits(ElTy); | |||
| 571 | ||||
| 572 | // Calculate the known alignment of the field. If the original aggregate | |||
| 573 | // had 256 byte alignment for example, something might depend on that: | |||
| 574 | // propagate info to each field. | |||
| 575 | Align NewAlign = commonAlignment(StartAlignment, EltSize * ElementIdx); | |||
| 576 | if (NewAlign > EltAlign) | |||
| 577 | NGV->setAlignment(NewAlign); | |||
| 578 | transferSRADebugInfo(GV, NGV, FragmentSizeInBits * ElementIdx, | |||
| 579 | FragmentSizeInBits, VarSize); | |||
| 580 | } | |||
| 581 | } | |||
| 582 | ||||
| 583 | if (NewGlobals.empty()) | |||
| 584 | return nullptr; | |||
| 585 | ||||
| 586 | Module::GlobalListType &Globals = GV->getParent()->getGlobalList(); | |||
| 587 | for (auto NewGlobalVar : NewGlobals) | |||
| 588 | Globals.push_back(NewGlobalVar.second); | |||
| 589 | ||||
| 590 | LLVM_DEBUG(dbgs() << "PERFORMING GLOBAL SRA ON: " << *GV << "\n")do { } while (false); | |||
| 591 | ||||
| 592 | Constant *NullInt =Constant::getNullValue(Type::getInt32Ty(GV->getContext())); | |||
| 593 | ||||
| 594 | // Loop over all of the uses of the global, replacing the constantexpr geps, | |||
| 595 | // with smaller constantexpr geps or direct references. | |||
| 596 | while (!GV->use_empty()) { | |||
| 597 | User *GEP = GV->user_back(); | |||
| 598 | assert(((isa<ConstantExpr>(GEP) &&((void)0) | |||
| 599 | cast<ConstantExpr>(GEP)->getOpcode()==Instruction::GetElementPtr)||((void)0) | |||
| 600 | isa<GetElementPtrInst>(GEP)) && "NonGEP CE's are not SRAable!")((void)0); | |||
| 601 | ||||
| 602 | // Ignore the 1th operand, which has to be zero or else the program is quite | |||
| 603 | // broken (undefined). Get the 2nd operand, which is the structure or array | |||
| 604 | // index. | |||
| 605 | unsigned ElementIdx = cast<ConstantInt>(GEP->getOperand(2))->getZExtValue(); | |||
| 606 | assert(NewGlobals.count(ElementIdx) == 1)((void)0); | |||
| 607 | ||||
| 608 | Value *NewPtr = NewGlobals[ElementIdx]; | |||
| 609 | Type *NewTy = NewGlobals[ElementIdx]->getValueType(); | |||
| 610 | ||||
| 611 | // Form a shorter GEP if needed. | |||
| 612 | if (GEP->getNumOperands() > 3) { | |||
| 613 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(GEP)) { | |||
| 614 | SmallVector<Constant*, 8> Idxs; | |||
| 615 | Idxs.push_back(NullInt); | |||
| 616 | for (unsigned i = 3, e = CE->getNumOperands(); i != e; ++i) | |||
| 617 | Idxs.push_back(CE->getOperand(i)); | |||
| 618 | NewPtr = | |||
| 619 | ConstantExpr::getGetElementPtr(NewTy, cast<Constant>(NewPtr), Idxs); | |||
| 620 | } else { | |||
| 621 | GetElementPtrInst *GEPI = cast<GetElementPtrInst>(GEP); | |||
| 622 | SmallVector<Value*, 8> Idxs; | |||
| 623 | Idxs.push_back(NullInt); | |||
| 624 | for (unsigned i = 3, e = GEPI->getNumOperands(); i != e; ++i) | |||
| 625 | Idxs.push_back(GEPI->getOperand(i)); | |||
| 626 | NewPtr = GetElementPtrInst::Create( | |||
| 627 | NewTy, NewPtr, Idxs, GEPI->getName() + "." + Twine(ElementIdx), | |||
| 628 | GEPI); | |||
| 629 | } | |||
| 630 | } | |||
| 631 | GEP->replaceAllUsesWith(NewPtr); | |||
| 632 | ||||
| 633 | // We changed the pointer of any memory access user. Recalculate alignments. | |||
| 634 | for (User *U : NewPtr->users()) { | |||
| 635 | if (auto *Load = dyn_cast<LoadInst>(U)) { | |||
| 636 | Align PrefAlign = DL.getPrefTypeAlign(Load->getType()); | |||
| 637 | Align NewAlign = getOrEnforceKnownAlignment(Load->getPointerOperand(), | |||
| 638 | PrefAlign, DL, Load); | |||
| 639 | Load->setAlignment(NewAlign); | |||
| 640 | } | |||
| 641 | if (auto *Store = dyn_cast<StoreInst>(U)) { | |||
| 642 | Align PrefAlign = | |||
| 643 | DL.getPrefTypeAlign(Store->getValueOperand()->getType()); | |||
| 644 | Align NewAlign = getOrEnforceKnownAlignment(Store->getPointerOperand(), | |||
| 645 | PrefAlign, DL, Store); | |||
| 646 | Store->setAlignment(NewAlign); | |||
| 647 | } | |||
| 648 | } | |||
| 649 | ||||
| 650 | if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(GEP)) | |||
| 651 | GEPI->eraseFromParent(); | |||
| 652 | else | |||
| 653 | cast<ConstantExpr>(GEP)->destroyConstant(); | |||
| 654 | } | |||
| 655 | ||||
| 656 | // Delete the old global, now that it is dead. | |||
| 657 | Globals.erase(GV); | |||
| 658 | ++NumSRA; | |||
| 659 | ||||
| 660 | assert(NewGlobals.size() > 0)((void)0); | |||
| 661 | return NewGlobals.begin()->second; | |||
| 662 | } | |||
| 663 | ||||
| 664 | /// Return true if all users of the specified value will trap if the value is | |||
| 665 | /// dynamically null. PHIs keeps track of any phi nodes we've seen to avoid | |||
| 666 | /// reprocessing them. | |||
| 667 | static bool AllUsesOfValueWillTrapIfNull(const Value *V, | |||
| 668 | SmallPtrSetImpl<const PHINode*> &PHIs) { | |||
| 669 | for (const User *U : V->users()) { | |||
| 670 | if (const Instruction *I = dyn_cast<Instruction>(U)) { | |||
| 671 | // If null pointer is considered valid, then all uses are non-trapping. | |||
| 672 | // Non address-space 0 globals have already been pruned by the caller. | |||
| 673 | if (NullPointerIsDefined(I->getFunction())) | |||
| 674 | return false; | |||
| 675 | } | |||
| 676 | if (isa<LoadInst>(U)) { | |||
| 677 | // Will trap. | |||
| 678 | } else if (const StoreInst *SI = dyn_cast<StoreInst>(U)) { | |||
| 679 | if (SI->getOperand(0) == V) { | |||
| 680 | //cerr << "NONTRAPPING USE: " << *U; | |||
| 681 | return false; // Storing the value. | |||
| 682 | } | |||
| 683 | } else if (const CallInst *CI = dyn_cast<CallInst>(U)) { | |||
| 684 | if (CI->getCalledOperand() != V) { | |||
| 685 | //cerr << "NONTRAPPING USE: " << *U; | |||
| 686 | return false; // Not calling the ptr | |||
| 687 | } | |||
| 688 | } else if (const InvokeInst *II = dyn_cast<InvokeInst>(U)) { | |||
| 689 | if (II->getCalledOperand() != V) { | |||
| 690 | //cerr << "NONTRAPPING USE: " << *U; | |||
| 691 | return false; // Not calling the ptr | |||
| 692 | } | |||
| 693 | } else if (const BitCastInst *CI = dyn_cast<BitCastInst>(U)) { | |||
| 694 | if (!AllUsesOfValueWillTrapIfNull(CI, PHIs)) return false; | |||
| 695 | } else if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(U)) { | |||
| 696 | if (!AllUsesOfValueWillTrapIfNull(GEPI, PHIs)) return false; | |||
| 697 | } else if (const PHINode *PN = dyn_cast<PHINode>(U)) { | |||
| 698 | // If we've already seen this phi node, ignore it, it has already been | |||
| 699 | // checked. | |||
| 700 | if (PHIs.insert(PN).second && !AllUsesOfValueWillTrapIfNull(PN, PHIs)) | |||
| 701 | return false; | |||
| 702 | } else if (isa<ICmpInst>(U) && | |||
| 703 | !ICmpInst::isSigned(cast<ICmpInst>(U)->getPredicate()) && | |||
| 704 | isa<LoadInst>(U->getOperand(0)) && | |||
| 705 | isa<ConstantPointerNull>(U->getOperand(1))) { | |||
| 706 | assert(isa<GlobalValue>(((void)0) | |||
| 707 | cast<LoadInst>(U->getOperand(0))->getPointerOperand()) &&((void)0) | |||
| 708 | "Should be GlobalVariable")((void)0); | |||
| 709 | // This and only this kind of non-signed ICmpInst is to be replaced with | |||
| 710 | // the comparing of the value of the created global init bool later in | |||
| 711 | // optimizeGlobalAddressOfMalloc for the global variable. | |||
| 712 | } else { | |||
| 713 | //cerr << "NONTRAPPING USE: " << *U; | |||
| 714 | return false; | |||
| 715 | } | |||
| 716 | } | |||
| 717 | return true; | |||
| 718 | } | |||
| 719 | ||||
| 720 | /// Return true if all uses of any loads from GV will trap if the loaded value | |||
| 721 | /// is null. Note that this also permits comparisons of the loaded value | |||
| 722 | /// against null, as a special case. | |||
| 723 | static bool AllUsesOfLoadedValueWillTrapIfNull(const GlobalVariable *GV) { | |||
| 724 | for (const User *U : GV->users()) | |||
| 725 | if (const LoadInst *LI = dyn_cast<LoadInst>(U)) { | |||
| 726 | SmallPtrSet<const PHINode*, 8> PHIs; | |||
| 727 | if (!AllUsesOfValueWillTrapIfNull(LI, PHIs)) | |||
| 728 | return false; | |||
| 729 | } else if (isa<StoreInst>(U)) { | |||
| 730 | // Ignore stores to the global. | |||
| 731 | } else { | |||
| 732 | // We don't know or understand this user, bail out. | |||
| 733 | //cerr << "UNKNOWN USER OF GLOBAL!: " << *U; | |||
| 734 | return false; | |||
| 735 | } | |||
| 736 | return true; | |||
| 737 | } | |||
| 738 | ||||
| 739 | static bool OptimizeAwayTrappingUsesOfValue(Value *V, Constant *NewV) { | |||
| 740 | bool Changed = false; | |||
| 741 | for (auto UI = V->user_begin(), E = V->user_end(); UI != E; ) { | |||
| 742 | Instruction *I = cast<Instruction>(*UI++); | |||
| 743 | // Uses are non-trapping if null pointer is considered valid. | |||
| 744 | // Non address-space 0 globals are already pruned by the caller. | |||
| 745 | if (NullPointerIsDefined(I->getFunction())) | |||
| 746 | return false; | |||
| 747 | if (LoadInst *LI = dyn_cast<LoadInst>(I)) { | |||
| 748 | LI->setOperand(0, NewV); | |||
| 749 | Changed = true; | |||
| 750 | } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) { | |||
| 751 | if (SI->getOperand(1) == V) { | |||
| 752 | SI->setOperand(1, NewV); | |||
| 753 | Changed = true; | |||
| 754 | } | |||
| 755 | } else if (isa<CallInst>(I) || isa<InvokeInst>(I)) { | |||
| 756 | CallBase *CB = cast<CallBase>(I); | |||
| 757 | if (CB->getCalledOperand() == V) { | |||
| 758 | // Calling through the pointer! Turn into a direct call, but be careful | |||
| 759 | // that the pointer is not also being passed as an argument. | |||
| 760 | CB->setCalledOperand(NewV); | |||
| 761 | Changed = true; | |||
| 762 | bool PassedAsArg = false; | |||
| 763 | for (unsigned i = 0, e = CB->arg_size(); i != e; ++i) | |||
| 764 | if (CB->getArgOperand(i) == V) { | |||
| 765 | PassedAsArg = true; | |||
| 766 | CB->setArgOperand(i, NewV); | |||
| 767 | } | |||
| 768 | ||||
| 769 | if (PassedAsArg) { | |||
| 770 | // Being passed as an argument also. Be careful to not invalidate UI! | |||
| 771 | UI = V->user_begin(); | |||
| 772 | } | |||
| 773 | } | |||
| 774 | } else if (CastInst *CI = dyn_cast<CastInst>(I)) { | |||
| 775 | Changed |= OptimizeAwayTrappingUsesOfValue(CI, | |||
| 776 | ConstantExpr::getCast(CI->getOpcode(), | |||
| 777 | NewV, CI->getType())); | |||
| 778 | if (CI->use_empty()) { | |||
| 779 | Changed = true; | |||
| 780 | CI->eraseFromParent(); | |||
| 781 | } | |||
| 782 | } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) { | |||
| 783 | // Should handle GEP here. | |||
| 784 | SmallVector<Constant*, 8> Idxs; | |||
| 785 | Idxs.reserve(GEPI->getNumOperands()-1); | |||
| 786 | for (User::op_iterator i = GEPI->op_begin() + 1, e = GEPI->op_end(); | |||
| 787 | i != e; ++i) | |||
| 788 | if (Constant *C = dyn_cast<Constant>(*i)) | |||
| 789 | Idxs.push_back(C); | |||
| 790 | else | |||
| 791 | break; | |||
| 792 | if (Idxs.size() == GEPI->getNumOperands()-1) | |||
| 793 | Changed |= OptimizeAwayTrappingUsesOfValue( | |||
| 794 | GEPI, ConstantExpr::getGetElementPtr(GEPI->getSourceElementType(), | |||
| 795 | NewV, Idxs)); | |||
| 796 | if (GEPI->use_empty()) { | |||
| 797 | Changed = true; | |||
| 798 | GEPI->eraseFromParent(); | |||
| 799 | } | |||
| 800 | } | |||
| 801 | } | |||
| 802 | ||||
| 803 | return Changed; | |||
| 804 | } | |||
| 805 | ||||
| 806 | /// The specified global has only one non-null value stored into it. If there | |||
| 807 | /// are uses of the loaded value that would trap if the loaded value is | |||
| 808 | /// dynamically null, then we know that they cannot be reachable with a null | |||
| 809 | /// optimize away the load. | |||
| 810 | static bool OptimizeAwayTrappingUsesOfLoads( | |||
| 811 | GlobalVariable *GV, Constant *LV, const DataLayout &DL, | |||
| 812 | function_ref<TargetLibraryInfo &(Function &)> GetTLI) { | |||
| 813 | bool Changed = false; | |||
| 814 | ||||
| 815 | // Keep track of whether we are able to remove all the uses of the global | |||
| 816 | // other than the store that defines it. | |||
| 817 | bool AllNonStoreUsesGone = true; | |||
| 818 | ||||
| 819 | // Replace all uses of loads with uses of uses of the stored value. | |||
| 820 | for (Value::user_iterator GUI = GV->user_begin(), E = GV->user_end(); GUI != E;){ | |||
| 821 | User *GlobalUser = *GUI++; | |||
| 822 | if (LoadInst *LI = dyn_cast<LoadInst>(GlobalUser)) { | |||
| 823 | Changed |= OptimizeAwayTrappingUsesOfValue(LI, LV); | |||
| 824 | // If we were able to delete all uses of the loads | |||
| 825 | if (LI->use_empty()) { | |||
| 826 | LI->eraseFromParent(); | |||
| 827 | Changed = true; | |||
| 828 | } else { | |||
| 829 | AllNonStoreUsesGone = false; | |||
| 830 | } | |||
| 831 | } else if (isa<StoreInst>(GlobalUser)) { | |||
| 832 | // Ignore the store that stores "LV" to the global. | |||
| 833 | assert(GlobalUser->getOperand(1) == GV &&((void)0) | |||
| 834 | "Must be storing *to* the global")((void)0); | |||
| 835 | } else { | |||
| 836 | AllNonStoreUsesGone = false; | |||
| 837 | ||||
| 838 | // If we get here we could have other crazy uses that are transitively | |||
| 839 | // loaded. | |||
| 840 | assert((isa<PHINode>(GlobalUser) || isa<SelectInst>(GlobalUser) ||((void)0) | |||
| 841 | isa<ConstantExpr>(GlobalUser) || isa<CmpInst>(GlobalUser) ||((void)0) | |||
| 842 | isa<BitCastInst>(GlobalUser) ||((void)0) | |||
| 843 | isa<GetElementPtrInst>(GlobalUser)) &&((void)0) | |||
| 844 | "Only expect load and stores!")((void)0); | |||
| 845 | } | |||
| 846 | } | |||
| 847 | ||||
| 848 | if (Changed) { | |||
| 849 | LLVM_DEBUG(dbgs() << "OPTIMIZED LOADS FROM STORED ONCE POINTER: " << *GVdo { } while (false) | |||
| 850 | << "\n")do { } while (false); | |||
| 851 | ++NumGlobUses; | |||
| 852 | } | |||
| 853 | ||||
| 854 | // If we nuked all of the loads, then none of the stores are needed either, | |||
| 855 | // nor is the global. | |||
| 856 | if (AllNonStoreUsesGone) { | |||
| 857 | if (isLeakCheckerRoot(GV)) { | |||
| 858 | Changed |= CleanupPointerRootUsers(GV, GetTLI); | |||
| 859 | } else { | |||
| 860 | Changed = true; | |||
| 861 | CleanupConstantGlobalUsers(GV, nullptr, DL, GetTLI); | |||
| 862 | } | |||
| 863 | if (GV->use_empty()) { | |||
| 864 | LLVM_DEBUG(dbgs() << " *** GLOBAL NOW DEAD!\n")do { } while (false); | |||
| 865 | Changed = true; | |||
| 866 | GV->eraseFromParent(); | |||
| 867 | ++NumDeleted; | |||
| 868 | } | |||
| 869 | } | |||
| 870 | return Changed; | |||
| 871 | } | |||
| 872 | ||||
| 873 | /// Walk the use list of V, constant folding all of the instructions that are | |||
| 874 | /// foldable. | |||
| 875 | static void ConstantPropUsersOf(Value *V, const DataLayout &DL, | |||
| 876 | TargetLibraryInfo *TLI) { | |||
| 877 | for (Value::user_iterator UI = V->user_begin(), E = V->user_end(); UI != E; ) | |||
| 878 | if (Instruction *I = dyn_cast<Instruction>(*UI++)) | |||
| 879 | if (Constant *NewC = ConstantFoldInstruction(I, DL, TLI)) { | |||
| 880 | I->replaceAllUsesWith(NewC); | |||
| 881 | ||||
| 882 | // Advance UI to the next non-I use to avoid invalidating it! | |||
| 883 | // Instructions could multiply use V. | |||
| 884 | while (UI != E && *UI == I) | |||
| 885 | ++UI; | |||
| 886 | if (isInstructionTriviallyDead(I, TLI)) | |||
| 887 | I->eraseFromParent(); | |||
| 888 | } | |||
| 889 | } | |||
| 890 | ||||
| 891 | /// This function takes the specified global variable, and transforms the | |||
| 892 | /// program as if it always contained the result of the specified malloc. | |||
| 893 | /// Because it is always the result of the specified malloc, there is no reason | |||
| 894 | /// to actually DO the malloc. Instead, turn the malloc into a global, and any | |||
| 895 | /// loads of GV as uses of the new global. | |||
| 896 | static GlobalVariable * | |||
| 897 | OptimizeGlobalAddressOfMalloc(GlobalVariable *GV, CallInst *CI, Type *AllocTy, | |||
| 898 | ConstantInt *NElements, const DataLayout &DL, | |||
| 899 | TargetLibraryInfo *TLI) { | |||
| 900 | LLVM_DEBUG(errs() << "PROMOTING GLOBAL: " << *GV << " CALL = " << *CIdo { } while (false) | |||
| 901 | << '\n')do { } while (false); | |||
| 902 | ||||
| 903 | Type *GlobalType; | |||
| 904 | if (NElements->getZExtValue() == 1) | |||
| 905 | GlobalType = AllocTy; | |||
| 906 | else | |||
| 907 | // If we have an array allocation, the global variable is of an array. | |||
| 908 | GlobalType = ArrayType::get(AllocTy, NElements->getZExtValue()); | |||
| 909 | ||||
| 910 | // Create the new global variable. The contents of the malloc'd memory is | |||
| 911 | // undefined, so initialize with an undef value. | |||
| 912 | GlobalVariable *NewGV = new GlobalVariable( | |||
| 913 | *GV->getParent(), GlobalType, false, GlobalValue::InternalLinkage, | |||
| 914 | UndefValue::get(GlobalType), GV->getName() + ".body", nullptr, | |||
| 915 | GV->getThreadLocalMode()); | |||
| 916 | ||||
| 917 | // If there are bitcast users of the malloc (which is typical, usually we have | |||
| 918 | // a malloc + bitcast) then replace them with uses of the new global. Update | |||
| 919 | // other users to use the global as well. | |||
| 920 | BitCastInst *TheBC = nullptr; | |||
| 921 | while (!CI->use_empty()) { | |||
| 922 | Instruction *User = cast<Instruction>(CI->user_back()); | |||
| 923 | if (BitCastInst *BCI = dyn_cast<BitCastInst>(User)) { | |||
| 924 | if (BCI->getType() == NewGV->getType()) { | |||
| 925 | BCI->replaceAllUsesWith(NewGV); | |||
| 926 | BCI->eraseFromParent(); | |||
| 927 | } else { | |||
| 928 | BCI->setOperand(0, NewGV); | |||
| 929 | } | |||
| 930 | } else { | |||
| 931 | if (!TheBC) | |||
| 932 | TheBC = new BitCastInst(NewGV, CI->getType(), "newgv", CI); | |||
| 933 | User->replaceUsesOfWith(CI, TheBC); | |||
| 934 | } | |||
| 935 | } | |||
| 936 | ||||
| 937 | Constant *RepValue = NewGV; | |||
| 938 | if (NewGV->getType() != GV->getValueType()) | |||
| 939 | RepValue = ConstantExpr::getBitCast(RepValue, GV->getValueType()); | |||
| 940 | ||||
| 941 | // If there is a comparison against null, we will insert a global bool to | |||
| 942 | // keep track of whether the global was initialized yet or not. | |||
| 943 | GlobalVariable *InitBool = | |||
| 944 | new GlobalVariable(Type::getInt1Ty(GV->getContext()), false, | |||
| 945 | GlobalValue::InternalLinkage, | |||
| 946 | ConstantInt::getFalse(GV->getContext()), | |||
| 947 | GV->getName()+".init", GV->getThreadLocalMode()); | |||
| 948 | bool InitBoolUsed = false; | |||
| 949 | ||||
| 950 | // Loop over all uses of GV, processing them in turn. | |||
| 951 | while (!GV->use_empty()) { | |||
| 952 | if (StoreInst *SI = dyn_cast<StoreInst>(GV->user_back())) { | |||
| 953 | // The global is initialized when the store to it occurs. If the stored | |||
| 954 | // value is null value, the global bool is set to false, otherwise true. | |||
| 955 | new StoreInst(ConstantInt::getBool( | |||
| 956 | GV->getContext(), | |||
| 957 | !isa<ConstantPointerNull>(SI->getValueOperand())), | |||
| 958 | InitBool, false, Align(1), SI->getOrdering(), | |||
| 959 | SI->getSyncScopeID(), SI); | |||
| 960 | SI->eraseFromParent(); | |||
| 961 | continue; | |||
| 962 | } | |||
| 963 | ||||
| 964 | LoadInst *LI = cast<LoadInst>(GV->user_back()); | |||
| 965 | while (!LI->use_empty()) { | |||
| 966 | Use &LoadUse = *LI->use_begin(); | |||
| 967 | ICmpInst *ICI = dyn_cast<ICmpInst>(LoadUse.getUser()); | |||
| 968 | if (!ICI) { | |||
| 969 | LoadUse = RepValue; | |||
| 970 | continue; | |||
| 971 | } | |||
| 972 | ||||
| 973 | // Replace the cmp X, 0 with a use of the bool value. | |||
| 974 | Value *LV = new LoadInst(InitBool->getValueType(), InitBool, | |||
| 975 | InitBool->getName() + ".val", false, Align(1), | |||
| 976 | LI->getOrdering(), LI->getSyncScopeID(), LI); | |||
| 977 | InitBoolUsed = true; | |||
| 978 | switch (ICI->getPredicate()) { | |||
| 979 | default: llvm_unreachable("Unknown ICmp Predicate!")__builtin_unreachable(); | |||
| 980 | case ICmpInst::ICMP_ULT: // X < null -> always false | |||
| 981 | LV = ConstantInt::getFalse(GV->getContext()); | |||
| 982 | break; | |||
| 983 | case ICmpInst::ICMP_UGE: // X >= null -> always true | |||
| 984 | LV = ConstantInt::getTrue(GV->getContext()); | |||
| 985 | break; | |||
| 986 | case ICmpInst::ICMP_ULE: | |||
| 987 | case ICmpInst::ICMP_EQ: | |||
| 988 | LV = BinaryOperator::CreateNot(LV, "notinit", ICI); | |||
| 989 | break; | |||
| 990 | case ICmpInst::ICMP_NE: | |||
| 991 | case ICmpInst::ICMP_UGT: | |||
| 992 | break; // no change. | |||
| 993 | } | |||
| 994 | ICI->replaceAllUsesWith(LV); | |||
| 995 | ICI->eraseFromParent(); | |||
| 996 | } | |||
| 997 | LI->eraseFromParent(); | |||
| 998 | } | |||
| 999 | ||||
| 1000 | // If the initialization boolean was used, insert it, otherwise delete it. | |||
| 1001 | if (!InitBoolUsed) { | |||
| 1002 | while (!InitBool->use_empty()) // Delete initializations | |||
| 1003 | cast<StoreInst>(InitBool->user_back())->eraseFromParent(); | |||
| 1004 | delete InitBool; | |||
| 1005 | } else | |||
| 1006 | GV->getParent()->getGlobalList().insert(GV->getIterator(), InitBool); | |||
| 1007 | ||||
| 1008 | // Now the GV is dead, nuke it and the malloc.. | |||
| 1009 | GV->eraseFromParent(); | |||
| 1010 | CI->eraseFromParent(); | |||
| 1011 | ||||
| 1012 | // To further other optimizations, loop over all users of NewGV and try to | |||
| 1013 | // constant prop them. This will promote GEP instructions with constant | |||
| 1014 | // indices into GEP constant-exprs, which will allow global-opt to hack on it. | |||
| 1015 | ConstantPropUsersOf(NewGV, DL, TLI); | |||
| 1016 | if (RepValue != NewGV) | |||
| 1017 | ConstantPropUsersOf(RepValue, DL, TLI); | |||
| 1018 | ||||
| 1019 | return NewGV; | |||
| 1020 | } | |||
| 1021 | ||||
| 1022 | /// Scan the use-list of V checking to make sure that there are no complex uses | |||
| 1023 | /// of V. We permit simple things like dereferencing the pointer, but not | |||
| 1024 | /// storing through the address, unless it is to the specified global. | |||
| 1025 | static bool | |||
| 1026 | valueIsOnlyUsedLocallyOrStoredToOneGlobal(const Instruction *V, | |||
| 1027 | const GlobalVariable *GV) { | |||
| 1028 | for (const User *U : V->users()) { | |||
| 1029 | const Instruction *Inst = cast<Instruction>(U); | |||
| 1030 | ||||
| 1031 | if (isa<LoadInst>(Inst) || isa<CmpInst>(Inst)) { | |||
| 1032 | continue; // Fine, ignore. | |||
| 1033 | } | |||
| 1034 | ||||
| 1035 | if (const StoreInst *SI = dyn_cast<StoreInst>(Inst)) { | |||
| 1036 | if (SI->getOperand(0) == V && SI->getOperand(1) != GV) | |||
| 1037 | return false; // Storing the pointer itself... bad. | |||
| 1038 | continue; // Otherwise, storing through it, or storing into GV... fine. | |||
| 1039 | } | |||
| 1040 | ||||
| 1041 | if (const BitCastInst *BCI = dyn_cast<BitCastInst>(Inst)) { | |||
| 1042 | if (!valueIsOnlyUsedLocallyOrStoredToOneGlobal(BCI, GV)) | |||
| 1043 | return false; | |||
| 1044 | continue; | |||
| 1045 | } | |||
| 1046 | ||||
| 1047 | return false; | |||
| 1048 | } | |||
| 1049 | return true; | |||
| 1050 | } | |||
| 1051 | ||||
| 1052 | /// This function is called when we see a pointer global variable with a single | |||
| 1053 | /// value stored it that is a malloc or cast of malloc. | |||
| 1054 | static bool tryToOptimizeStoreOfMallocToGlobal(GlobalVariable *GV, CallInst *CI, | |||
| 1055 | Type *AllocTy, | |||
| 1056 | AtomicOrdering Ordering, | |||
| 1057 | const DataLayout &DL, | |||
| 1058 | TargetLibraryInfo *TLI) { | |||
| 1059 | // If this is a malloc of an abstract type, don't touch it. | |||
| 1060 | if (!AllocTy->isSized()) | |||
| 1061 | return false; | |||
| 1062 | ||||
| 1063 | // We can't optimize this global unless all uses of it are *known* to be | |||
| 1064 | // of the malloc value, not of the null initializer value (consider a use | |||
| 1065 | // that compares the global's value against zero to see if the malloc has | |||
| 1066 | // been reached). To do this, we check to see if all uses of the global | |||
| 1067 | // would trap if the global were null: this proves that they must all | |||
| 1068 | // happen after the malloc. | |||
| 1069 | if (!AllUsesOfLoadedValueWillTrapIfNull(GV)) | |||
| 1070 | return false; | |||
| 1071 | ||||
| 1072 | // We can't optimize this if the malloc itself is used in a complex way, | |||
| 1073 | // for example, being stored into multiple globals. This allows the | |||
| 1074 | // malloc to be stored into the specified global, loaded icmp'd. | |||
| 1075 | // These are all things we could transform to using the global for. | |||
| 1076 | if (!valueIsOnlyUsedLocallyOrStoredToOneGlobal(CI, GV)) | |||
| 1077 | return false; | |||
| 1078 | ||||
| 1079 | // If we have a global that is only initialized with a fixed size malloc, | |||
| 1080 | // transform the program to use global memory instead of malloc'd memory. | |||
| 1081 | // This eliminates dynamic allocation, avoids an indirection accessing the | |||
| 1082 | // data, and exposes the resultant global to further GlobalOpt. | |||
| 1083 | // We cannot optimize the malloc if we cannot determine malloc array size. | |||
| 1084 | Value *NElems = getMallocArraySize(CI, DL, TLI, true); | |||
| 1085 | if (!NElems) | |||
| 1086 | return false; | |||
| 1087 | ||||
| 1088 | if (ConstantInt *NElements = dyn_cast<ConstantInt>(NElems)) | |||
| 1089 | // Restrict this transformation to only working on small allocations | |||
| 1090 | // (2048 bytes currently), as we don't want to introduce a 16M global or | |||
| 1091 | // something. | |||
| 1092 | if (NElements->getZExtValue() * DL.getTypeAllocSize(AllocTy) < 2048) { | |||
| 1093 | OptimizeGlobalAddressOfMalloc(GV, CI, AllocTy, NElements, DL, TLI); | |||
| 1094 | return true; | |||
| 1095 | } | |||
| 1096 | ||||
| 1097 | return false; | |||
| 1098 | } | |||
| 1099 | ||||
| 1100 | // Try to optimize globals based on the knowledge that only one value (besides | |||
| 1101 | // its initializer) is ever stored to the global. | |||
| 1102 | static bool | |||
| 1103 | optimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal, | |||
| 1104 | AtomicOrdering Ordering, const DataLayout &DL, | |||
| 1105 | function_ref<TargetLibraryInfo &(Function &)> GetTLI) { | |||
| 1106 | // Ignore no-op GEPs and bitcasts. | |||
| 1107 | StoredOnceVal = StoredOnceVal->stripPointerCasts(); | |||
| 1108 | ||||
| 1109 | // If we are dealing with a pointer global that is initialized to null and | |||
| 1110 | // only has one (non-null) value stored into it, then we can optimize any | |||
| 1111 | // users of the loaded value (often calls and loads) that would trap if the | |||
| 1112 | // value was null. | |||
| 1113 | if (GV->getInitializer()->getType()->isPointerTy() && | |||
| 1114 | GV->getInitializer()->isNullValue() && | |||
| 1115 | !NullPointerIsDefined( | |||
| 1116 | nullptr /* F */, | |||
| 1117 | GV->getInitializer()->getType()->getPointerAddressSpace())) { | |||
| 1118 | if (Constant *SOVC = dyn_cast<Constant>(StoredOnceVal)) { | |||
| 1119 | if (GV->getInitializer()->getType() != SOVC->getType()) | |||
| 1120 | SOVC = ConstantExpr::getBitCast(SOVC, GV->getInitializer()->getType()); | |||
| 1121 | ||||
| 1122 | // Optimize away any trapping uses of the loaded value. | |||
| 1123 | if (OptimizeAwayTrappingUsesOfLoads(GV, SOVC, DL, GetTLI)) | |||
| 1124 | return true; | |||
| 1125 | } else if (CallInst *CI = extractMallocCall(StoredOnceVal, GetTLI)) { | |||
| 1126 | auto *TLI = &GetTLI(*CI->getFunction()); | |||
| 1127 | Type *MallocType = getMallocAllocatedType(CI, TLI); | |||
| 1128 | if (MallocType && tryToOptimizeStoreOfMallocToGlobal(GV, CI, MallocType, | |||
| 1129 | Ordering, DL, TLI)) | |||
| 1130 | return true; | |||
| 1131 | } | |||
| 1132 | } | |||
| 1133 | ||||
| 1134 | return false; | |||
| 1135 | } | |||
| 1136 | ||||
| 1137 | /// At this point, we have learned that the only two values ever stored into GV | |||
| 1138 | /// are its initializer and OtherVal. See if we can shrink the global into a | |||
| 1139 | /// boolean and select between the two values whenever it is used. This exposes | |||
| 1140 | /// the values to other scalar optimizations. | |||
| 1141 | static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { | |||
| 1142 | Type *GVElType = GV->getValueType(); | |||
| 1143 | ||||
| 1144 | // If GVElType is already i1, it is already shrunk. If the type of the GV is | |||
| 1145 | // an FP value, pointer or vector, don't do this optimization because a select | |||
| 1146 | // between them is very expensive and unlikely to lead to later | |||
| 1147 | // simplification. In these cases, we typically end up with "cond ? v1 : v2" | |||
| 1148 | // where v1 and v2 both require constant pool loads, a big loss. | |||
| 1149 | if (GVElType == Type::getInt1Ty(GV->getContext()) || | |||
| 1150 | GVElType->isFloatingPointTy() || | |||
| 1151 | GVElType->isPointerTy() || GVElType->isVectorTy()) | |||
| 1152 | return false; | |||
| 1153 | ||||
| 1154 | // Walk the use list of the global seeing if all the uses are load or store. | |||
| 1155 | // If there is anything else, bail out. | |||
| 1156 | for (User *U : GV->users()) | |||
| 1157 | if (!isa<LoadInst>(U) && !isa<StoreInst>(U)) | |||
| 1158 | return false; | |||
| 1159 | ||||
| 1160 | LLVM_DEBUG(dbgs() << " *** SHRINKING TO BOOL: " << *GV << "\n")do { } while (false); | |||
| 1161 | ||||
| 1162 | // Create the new global, initializing it to false. | |||
| 1163 | GlobalVariable *NewGV = new GlobalVariable(Type::getInt1Ty(GV->getContext()), | |||
| 1164 | false, | |||
| 1165 | GlobalValue::InternalLinkage, | |||
| 1166 | ConstantInt::getFalse(GV->getContext()), | |||
| 1167 | GV->getName()+".b", | |||
| 1168 | GV->getThreadLocalMode(), | |||
| 1169 | GV->getType()->getAddressSpace()); | |||
| 1170 | NewGV->copyAttributesFrom(GV); | |||
| 1171 | GV->getParent()->getGlobalList().insert(GV->getIterator(), NewGV); | |||
| 1172 | ||||
| 1173 | Constant *InitVal = GV->getInitializer(); | |||
| 1174 | assert(InitVal->getType() != Type::getInt1Ty(GV->getContext()) &&((void)0) | |||
| 1175 | "No reason to shrink to bool!")((void)0); | |||
| 1176 | ||||
| 1177 | SmallVector<DIGlobalVariableExpression *, 1> GVs; | |||
| 1178 | GV->getDebugInfo(GVs); | |||
| 1179 | ||||
| 1180 | // If initialized to zero and storing one into the global, we can use a cast | |||
| 1181 | // instead of a select to synthesize the desired value. | |||
| 1182 | bool IsOneZero = false; | |||
| 1183 | bool EmitOneOrZero = true; | |||
| 1184 | auto *CI = dyn_cast<ConstantInt>(OtherVal); | |||
| 1185 | if (CI && CI->getValue().getActiveBits() <= 64) { | |||
| 1186 | IsOneZero = InitVal->isNullValue() && CI->isOne(); | |||
| 1187 | ||||
| 1188 | auto *CIInit = dyn_cast<ConstantInt>(GV->getInitializer()); | |||
| 1189 | if (CIInit && CIInit->getValue().getActiveBits() <= 64) { | |||
| 1190 | uint64_t ValInit = CIInit->getZExtValue(); | |||
| 1191 | uint64_t ValOther = CI->getZExtValue(); | |||
| 1192 | uint64_t ValMinus = ValOther - ValInit; | |||
| 1193 | ||||
| 1194 | for(auto *GVe : GVs){ | |||
| 1195 | DIGlobalVariable *DGV = GVe->getVariable(); | |||
| 1196 | DIExpression *E = GVe->getExpression(); | |||
| 1197 | const DataLayout &DL = GV->getParent()->getDataLayout(); | |||
| 1198 | unsigned SizeInOctets = | |||
| 1199 | DL.getTypeAllocSizeInBits(NewGV->getValueType()) / 8; | |||
| 1200 | ||||
| 1201 | // It is expected that the address of global optimized variable is on | |||
| 1202 | // top of the stack. After optimization, value of that variable will | |||
| 1203 | // be ether 0 for initial value or 1 for other value. The following | |||
| 1204 | // expression should return constant integer value depending on the | |||
| 1205 | // value at global object address: | |||
| 1206 | // val * (ValOther - ValInit) + ValInit: | |||
| 1207 | // DW_OP_deref DW_OP_constu <ValMinus> | |||
| 1208 | // DW_OP_mul DW_OP_constu <ValInit> DW_OP_plus DW_OP_stack_value | |||
| 1209 | SmallVector<uint64_t, 12> Ops = { | |||
| 1210 | dwarf::DW_OP_deref_size, SizeInOctets, | |||
| 1211 | dwarf::DW_OP_constu, ValMinus, | |||
| 1212 | dwarf::DW_OP_mul, dwarf::DW_OP_constu, ValInit, | |||
| 1213 | dwarf::DW_OP_plus}; | |||
| 1214 | bool WithStackValue = true; | |||
| 1215 | E = DIExpression::prependOpcodes(E, Ops, WithStackValue); | |||
| 1216 | DIGlobalVariableExpression *DGVE = | |||
| 1217 | DIGlobalVariableExpression::get(NewGV->getContext(), DGV, E); | |||
| 1218 | NewGV->addDebugInfo(DGVE); | |||
| 1219 | } | |||
| 1220 | EmitOneOrZero = false; | |||
| 1221 | } | |||
| 1222 | } | |||
| 1223 | ||||
| 1224 | if (EmitOneOrZero) { | |||
| 1225 | // FIXME: This will only emit address for debugger on which will | |||
| 1226 | // be written only 0 or 1. | |||
| 1227 | for(auto *GV : GVs) | |||
| 1228 | NewGV->addDebugInfo(GV); | |||
| 1229 | } | |||
| 1230 | ||||
| 1231 | while (!GV->use_empty()) { | |||
| 1232 | Instruction *UI = cast<Instruction>(GV->user_back()); | |||
| 1233 | if (StoreInst *SI = dyn_cast<StoreInst>(UI)) { | |||
| 1234 | // Change the store into a boolean store. | |||
| 1235 | bool StoringOther = SI->getOperand(0) == OtherVal; | |||
| 1236 | // Only do this if we weren't storing a loaded value. | |||
| 1237 | Value *StoreVal; | |||
| 1238 | if (StoringOther || SI->getOperand(0) == InitVal) { | |||
| 1239 | StoreVal = ConstantInt::get(Type::getInt1Ty(GV->getContext()), | |||
| 1240 | StoringOther); | |||
| 1241 | } else { | |||
| 1242 | // Otherwise, we are storing a previously loaded copy. To do this, | |||
| 1243 | // change the copy from copying the original value to just copying the | |||
| 1244 | // bool. | |||
| 1245 | Instruction *StoredVal = cast<Instruction>(SI->getOperand(0)); | |||
| 1246 | ||||
| 1247 | // If we've already replaced the input, StoredVal will be a cast or | |||
| 1248 | // select instruction. If not, it will be a load of the original | |||
| 1249 | // global. | |||
| 1250 | if (LoadInst *LI = dyn_cast<LoadInst>(StoredVal)) { | |||
| 1251 | assert(LI->getOperand(0) == GV && "Not a copy!")((void)0); | |||
| 1252 | // Insert a new load, to preserve the saved value. | |||
| 1253 | StoreVal = new LoadInst(NewGV->getValueType(), NewGV, | |||
| 1254 | LI->getName() + ".b", false, Align(1), | |||
| 1255 | LI->getOrdering(), LI->getSyncScopeID(), LI); | |||
| 1256 | } else { | |||
| 1257 | assert((isa<CastInst>(StoredVal) || isa<SelectInst>(StoredVal)) &&((void)0) | |||
| 1258 | "This is not a form that we understand!")((void)0); | |||
| 1259 | StoreVal = StoredVal->getOperand(0); | |||
| 1260 | assert(isa<LoadInst>(StoreVal) && "Not a load of NewGV!")((void)0); | |||
| 1261 | } | |||
| 1262 | } | |||
| 1263 | StoreInst *NSI = | |||
| 1264 | new StoreInst(StoreVal, NewGV, false, Align(1), SI->getOrdering(), | |||
| 1265 | SI->getSyncScopeID(), SI); | |||
| 1266 | NSI->setDebugLoc(SI->getDebugLoc()); | |||
| 1267 | } else { | |||
| 1268 | // Change the load into a load of bool then a select. | |||
| 1269 | LoadInst *LI = cast<LoadInst>(UI); | |||
| 1270 | LoadInst *NLI = new LoadInst(NewGV->getValueType(), NewGV, | |||
| 1271 | LI->getName() + ".b", false, Align(1), | |||
| 1272 | LI->getOrdering(), LI->getSyncScopeID(), LI); | |||
| 1273 | Instruction *NSI; | |||
| 1274 | if (IsOneZero) | |||
| 1275 | NSI = new ZExtInst(NLI, LI->getType(), "", LI); | |||
| 1276 | else | |||
| 1277 | NSI = SelectInst::Create(NLI, OtherVal, InitVal, "", LI); | |||
| 1278 | NSI->takeName(LI); | |||
| 1279 | // Since LI is split into two instructions, NLI and NSI both inherit the | |||
| 1280 | // same DebugLoc | |||
| 1281 | NLI->setDebugLoc(LI->getDebugLoc()); | |||
| 1282 | NSI->setDebugLoc(LI->getDebugLoc()); | |||
| 1283 | LI->replaceAllUsesWith(NSI); | |||
| 1284 | } | |||
| 1285 | UI->eraseFromParent(); | |||
| 1286 | } | |||
| 1287 | ||||
| 1288 | // Retain the name of the old global variable. People who are debugging their | |||
| 1289 | // programs may expect these variables to be named the same. | |||
| 1290 | NewGV->takeName(GV); | |||
| 1291 | GV->eraseFromParent(); | |||
| 1292 | return true; | |||
| 1293 | } | |||
| 1294 | ||||
| 1295 | static bool deleteIfDead( | |||
| 1296 | GlobalValue &GV, SmallPtrSetImpl<const Comdat *> &NotDiscardableComdats) { | |||
| 1297 | GV.removeDeadConstantUsers(); | |||
| 1298 | ||||
| 1299 | if (!GV.isDiscardableIfUnused() && !GV.isDeclaration()) | |||
| 1300 | return false; | |||
| 1301 | ||||
| 1302 | if (const Comdat *C = GV.getComdat()) | |||
| 1303 | if (!GV.hasLocalLinkage() && NotDiscardableComdats.count(C)) | |||
| 1304 | return false; | |||
| 1305 | ||||
| 1306 | bool Dead; | |||
| 1307 | if (auto *F = dyn_cast<Function>(&GV)) | |||
| 1308 | Dead = (F->isDeclaration() && F->use_empty()) || F->isDefTriviallyDead(); | |||
| 1309 | else | |||
| 1310 | Dead = GV.use_empty(); | |||
| 1311 | if (!Dead) | |||
| 1312 | return false; | |||
| 1313 | ||||
| 1314 | LLVM_DEBUG(dbgs() << "GLOBAL DEAD: " << GV << "\n")do { } while (false); | |||
| 1315 | GV.eraseFromParent(); | |||
| 1316 | ++NumDeleted; | |||
| 1317 | return true; | |||
| 1318 | } | |||
| 1319 | ||||
| 1320 | static bool isPointerValueDeadOnEntryToFunction( | |||
| 1321 | const Function *F, GlobalValue *GV, | |||
| 1322 | function_ref<DominatorTree &(Function &)> LookupDomTree) { | |||
| 1323 | // Find all uses of GV. We expect them all to be in F, and if we can't | |||
| 1324 | // identify any of the uses we bail out. | |||
| 1325 | // | |||
| 1326 | // On each of these uses, identify if the memory that GV points to is | |||
| 1327 | // used/required/live at the start of the function. If it is not, for example | |||
| 1328 | // if the first thing the function does is store to the GV, the GV can | |||
| 1329 | // possibly be demoted. | |||
| 1330 | // | |||
| 1331 | // We don't do an exhaustive search for memory operations - simply look | |||
| 1332 | // through bitcasts as they're quite common and benign. | |||
| 1333 | const DataLayout &DL = GV->getParent()->getDataLayout(); | |||
| 1334 | SmallVector<LoadInst *, 4> Loads; | |||
| 1335 | SmallVector<StoreInst *, 4> Stores; | |||
| 1336 | for (auto *U : GV->users()) { | |||
| 1337 | if (Operator::getOpcode(U) == Instruction::BitCast) { | |||
| 1338 | for (auto *UU : U->users()) { | |||
| 1339 | if (auto *LI = dyn_cast<LoadInst>(UU)) | |||
| 1340 | Loads.push_back(LI); | |||
| 1341 | else if (auto *SI = dyn_cast<StoreInst>(UU)) | |||
| 1342 | Stores.push_back(SI); | |||
| 1343 | else | |||
| 1344 | return false; | |||
| 1345 | } | |||
| 1346 | continue; | |||
| 1347 | } | |||
| 1348 | ||||
| 1349 | Instruction *I = dyn_cast<Instruction>(U); | |||
| 1350 | if (!I) | |||
| 1351 | return false; | |||
| 1352 | assert(I->getParent()->getParent() == F)((void)0); | |||
| 1353 | ||||
| 1354 | if (auto *LI = dyn_cast<LoadInst>(I)) | |||
| 1355 | Loads.push_back(LI); | |||
| 1356 | else if (auto *SI = dyn_cast<StoreInst>(I)) | |||
| 1357 | Stores.push_back(SI); | |||
| 1358 | else | |||
| 1359 | return false; | |||
| 1360 | } | |||
| 1361 | ||||
| 1362 | // We have identified all uses of GV into loads and stores. Now check if all | |||
| 1363 | // of them are known not to depend on the value of the global at the function | |||
| 1364 | // entry point. We do this by ensuring that every load is dominated by at | |||
| 1365 | // least one store. | |||
| 1366 | auto &DT = LookupDomTree(*const_cast<Function *>(F)); | |||
| 1367 | ||||
| 1368 | // The below check is quadratic. Check we're not going to do too many tests. | |||
| 1369 | // FIXME: Even though this will always have worst-case quadratic time, we | |||
| 1370 | // could put effort into minimizing the average time by putting stores that | |||
| 1371 | // have been shown to dominate at least one load at the beginning of the | |||
| 1372 | // Stores array, making subsequent dominance checks more likely to succeed | |||
| 1373 | // early. | |||
| 1374 | // | |||
| 1375 | // The threshold here is fairly large because global->local demotion is a | |||
| 1376 | // very powerful optimization should it fire. | |||
| 1377 | const unsigned Threshold = 100; | |||
| 1378 | if (Loads.size() * Stores.size() > Threshold) | |||
| 1379 | return false; | |||
| 1380 | ||||
| 1381 | for (auto *L : Loads) { | |||
| 1382 | auto *LTy = L->getType(); | |||
| 1383 | if (none_of(Stores, [&](const StoreInst *S) { | |||
| 1384 | auto *STy = S->getValueOperand()->getType(); | |||
| 1385 | // The load is only dominated by the store if DomTree says so | |||
| 1386 | // and the number of bits loaded in L is less than or equal to | |||
| 1387 | // the number of bits stored in S. | |||
| 1388 | return DT.dominates(S, L) && | |||
| 1389 | DL.getTypeStoreSize(LTy).getFixedSize() <= | |||
| 1390 | DL.getTypeStoreSize(STy).getFixedSize(); | |||
| 1391 | })) | |||
| 1392 | return false; | |||
| 1393 | } | |||
| 1394 | // All loads have known dependences inside F, so the global can be localized. | |||
| 1395 | return true; | |||
| 1396 | } | |||
| 1397 | ||||
| 1398 | /// C may have non-instruction users. Can all of those users be turned into | |||
| 1399 | /// instructions? | |||
| 1400 | static bool allNonInstructionUsersCanBeMadeInstructions(Constant *C) { | |||
| 1401 | // We don't do this exhaustively. The most common pattern that we really need | |||
| 1402 | // to care about is a constant GEP or constant bitcast - so just looking | |||
| 1403 | // through one single ConstantExpr. | |||
| 1404 | // | |||
| 1405 | // The set of constants that this function returns true for must be able to be | |||
| 1406 | // handled by makeAllConstantUsesInstructions. | |||
| 1407 | for (auto *U : C->users()) { | |||
| 1408 | if (isa<Instruction>(U)) | |||
| 1409 | continue; | |||
| 1410 | if (!isa<ConstantExpr>(U)) | |||
| 1411 | // Non instruction, non-constantexpr user; cannot convert this. | |||
| 1412 | return false; | |||
| 1413 | for (auto *UU : U->users()) | |||
| 1414 | if (!isa<Instruction>(UU)) | |||
| 1415 | // A constantexpr used by another constant. We don't try and recurse any | |||
| 1416 | // further but just bail out at this point. | |||
| 1417 | return false; | |||
| 1418 | } | |||
| 1419 | ||||
| 1420 | return true; | |||
| 1421 | } | |||
| 1422 | ||||
| 1423 | /// C may have non-instruction users, and | |||
| 1424 | /// allNonInstructionUsersCanBeMadeInstructions has returned true. Convert the | |||
| 1425 | /// non-instruction users to instructions. | |||
| 1426 | static void makeAllConstantUsesInstructions(Constant *C) { | |||
| 1427 | SmallVector<ConstantExpr*,4> Users; | |||
| 1428 | for (auto *U : C->users()) { | |||
| 1429 | if (isa<ConstantExpr>(U)) | |||
| 1430 | Users.push_back(cast<ConstantExpr>(U)); | |||
| 1431 | else | |||
| 1432 | // We should never get here; allNonInstructionUsersCanBeMadeInstructions | |||
| 1433 | // should not have returned true for C. | |||
| 1434 | assert(((void)0) | |||
| 1435 | isa<Instruction>(U) &&((void)0) | |||
| 1436 | "Can't transform non-constantexpr non-instruction to instruction!")((void)0); | |||
| 1437 | } | |||
| 1438 | ||||
| 1439 | SmallVector<Value*,4> UUsers; | |||
| 1440 | for (auto *U : Users) { | |||
| 1441 | UUsers.clear(); | |||
| 1442 | append_range(UUsers, U->users()); | |||
| 1443 | for (auto *UU : UUsers) { | |||
| 1444 | Instruction *UI = cast<Instruction>(UU); | |||
| 1445 | Instruction *NewU = U->getAsInstruction(); | |||
| 1446 | NewU->insertBefore(UI); | |||
| 1447 | UI->replaceUsesOfWith(U, NewU); | |||
| 1448 | } | |||
| 1449 | // We've replaced all the uses, so destroy the constant. (destroyConstant | |||
| 1450 | // will update value handles and metadata.) | |||
| 1451 | U->destroyConstant(); | |||
| 1452 | } | |||
| 1453 | } | |||
| 1454 | ||||
| 1455 | /// Analyze the specified global variable and optimize | |||
| 1456 | /// it if possible. If we make a change, return true. | |||
| 1457 | static bool | |||
| 1458 | processInternalGlobal(GlobalVariable *GV, const GlobalStatus &GS, | |||
| 1459 | function_ref<TargetLibraryInfo &(Function &)> GetTLI, | |||
| 1460 | function_ref<DominatorTree &(Function &)> LookupDomTree) { | |||
| 1461 | auto &DL = GV->getParent()->getDataLayout(); | |||
| 1462 | // If this is a first class global and has only one accessing function and | |||
| 1463 | // this function is non-recursive, we replace the global with a local alloca | |||
| 1464 | // in this function. | |||
| 1465 | // | |||
| 1466 | // NOTE: It doesn't make sense to promote non-single-value types since we | |||
| 1467 | // are just replacing static memory to stack memory. | |||
| 1468 | // | |||
| 1469 | // If the global is in different address space, don't bring it to stack. | |||
| 1470 | if (!GS.HasMultipleAccessingFunctions && | |||
| 1471 | GS.AccessingFunction && | |||
| 1472 | GV->getValueType()->isSingleValueType() && | |||
| 1473 | GV->getType()->getAddressSpace() == 0 && | |||
| 1474 | !GV->isExternallyInitialized() && | |||
| 1475 | allNonInstructionUsersCanBeMadeInstructions(GV) && | |||
| 1476 | GS.AccessingFunction->doesNotRecurse() && | |||
| 1477 | isPointerValueDeadOnEntryToFunction(GS.AccessingFunction, GV, | |||
| 1478 | LookupDomTree)) { | |||
| 1479 | const DataLayout &DL = GV->getParent()->getDataLayout(); | |||
| 1480 | ||||
| 1481 | LLVM_DEBUG(dbgs() << "LOCALIZING GLOBAL: " << *GV << "\n")do { } while (false); | |||
| 1482 | Instruction &FirstI = const_cast<Instruction&>(*GS.AccessingFunction | |||
| 1483 | ->getEntryBlock().begin()); | |||
| 1484 | Type *ElemTy = GV->getValueType(); | |||
| 1485 | // FIXME: Pass Global's alignment when globals have alignment | |||
| 1486 | AllocaInst *Alloca = new AllocaInst(ElemTy, DL.getAllocaAddrSpace(), nullptr, | |||
| 1487 | GV->getName(), &FirstI); | |||
| 1488 | if (!isa<UndefValue>(GV->getInitializer())) | |||
| 1489 | new StoreInst(GV->getInitializer(), Alloca, &FirstI); | |||
| 1490 | ||||
| 1491 | makeAllConstantUsesInstructions(GV); | |||
| 1492 | ||||
| 1493 | GV->replaceAllUsesWith(Alloca); | |||
| 1494 | GV->eraseFromParent(); | |||
| 1495 | ++NumLocalized; | |||
| 1496 | return true; | |||
| 1497 | } | |||
| 1498 | ||||
| 1499 | bool Changed = false; | |||
| 1500 | ||||
| 1501 | // If the global is never loaded (but may be stored to), it is dead. | |||
| 1502 | // Delete it now. | |||
| 1503 | if (!GS.IsLoaded) { | |||
| 1504 | LLVM_DEBUG(dbgs() << "GLOBAL NEVER LOADED: " << *GV << "\n")do { } while (false); | |||
| 1505 | ||||
| 1506 | if (isLeakCheckerRoot(GV)) { | |||
| 1507 | // Delete any constant stores to the global. | |||
| 1508 | Changed = CleanupPointerRootUsers(GV, GetTLI); | |||
| 1509 | } else { | |||
| 1510 | // Delete any stores we can find to the global. We may not be able to | |||
| 1511 | // make it completely dead though. | |||
| 1512 | Changed = | |||
| 1513 | CleanupConstantGlobalUsers(GV, GV->getInitializer(), DL, GetTLI); | |||
| 1514 | } | |||
| 1515 | ||||
| 1516 | // If the global is dead now, delete it. | |||
| 1517 | if (GV->use_empty()) { | |||
| 1518 | GV->eraseFromParent(); | |||
| 1519 | ++NumDeleted; | |||
| 1520 | Changed = true; | |||
| 1521 | } | |||
| 1522 | return Changed; | |||
| 1523 | ||||
| 1524 | } | |||
| 1525 | if (GS.StoredType <= GlobalStatus::InitializerStored) { | |||
| 1526 | LLVM_DEBUG(dbgs() << "MARKING CONSTANT: " << *GV << "\n")do { } while (false); | |||
| 1527 | ||||
| 1528 | // Don't actually mark a global constant if it's atomic because atomic loads | |||
| 1529 | // are implemented by a trivial cmpxchg in some edge-cases and that usually | |||
| 1530 | // requires write access to the variable even if it's not actually changed. | |||
| 1531 | if (GS.Ordering == AtomicOrdering::NotAtomic) { | |||
| 1532 | assert(!GV->isConstant() && "Expected a non-constant global")((void)0); | |||
| 1533 | GV->setConstant(true); | |||
| 1534 | Changed = true; | |||
| 1535 | } | |||
| 1536 | ||||
| 1537 | // Clean up any obviously simplifiable users now. | |||
| 1538 | Changed |= CleanupConstantGlobalUsers(GV, GV->getInitializer(), DL, GetTLI); | |||
| 1539 | ||||
| 1540 | // If the global is dead now, just nuke it. | |||
| 1541 | if (GV->use_empty()) { | |||
| 1542 | LLVM_DEBUG(dbgs() << " *** Marking constant allowed us to simplify "do { } while (false) | |||
| 1543 | << "all users and delete global!\n")do { } while (false); | |||
| 1544 | GV->eraseFromParent(); | |||
| 1545 | ++NumDeleted; | |||
| 1546 | return true; | |||
| 1547 | } | |||
| 1548 | ||||
| 1549 | // Fall through to the next check; see if we can optimize further. | |||
| 1550 | ++NumMarked; | |||
| 1551 | } | |||
| 1552 | if (!GV->getInitializer()->getType()->isSingleValueType()) { | |||
| 1553 | const DataLayout &DL = GV->getParent()->getDataLayout(); | |||
| 1554 | if (SRAGlobal(GV, DL)) | |||
| 1555 | return true; | |||
| 1556 | } | |||
| 1557 | if (GS.StoredType == GlobalStatus::StoredOnce && GS.StoredOnceValue) { | |||
| 1558 | // If the initial value for the global was an undef value, and if only | |||
| 1559 | // one other value was stored into it, we can just change the | |||
| 1560 | // initializer to be the stored value, then delete all stores to the | |||
| 1561 | // global. This allows us to mark it constant. | |||
| 1562 | if (Constant *SOVConstant = dyn_cast<Constant>(GS.StoredOnceValue)) | |||
| 1563 | if (isa<UndefValue>(GV->getInitializer())) { | |||
| 1564 | // Change the initial value here. | |||
| 1565 | GV->setInitializer(SOVConstant); | |||
| 1566 | ||||
| 1567 | // Clean up any obviously simplifiable users now. | |||
| 1568 | CleanupConstantGlobalUsers(GV, GV->getInitializer(), DL, GetTLI); | |||
| 1569 | ||||
| 1570 | if (GV->use_empty()) { | |||
| 1571 | LLVM_DEBUG(dbgs() << " *** Substituting initializer allowed us to "do { } while (false) | |||
| 1572 | << "simplify all users and delete global!\n")do { } while (false); | |||
| 1573 | GV->eraseFromParent(); | |||
| 1574 | ++NumDeleted; | |||
| 1575 | } | |||
| 1576 | ++NumSubstitute; | |||
| 1577 | return true; | |||
| 1578 | } | |||
| 1579 | ||||
| 1580 | // Try to optimize globals based on the knowledge that only one value | |||
| 1581 | // (besides its initializer) is ever stored to the global. | |||
| 1582 | if (optimizeOnceStoredGlobal(GV, GS.StoredOnceValue, GS.Ordering, DL, | |||
| 1583 | GetTLI)) | |||
| 1584 | return true; | |||
| 1585 | ||||
| 1586 | // Otherwise, if the global was not a boolean, we can shrink it to be a | |||
| 1587 | // boolean. | |||
| 1588 | if (Constant *SOVConstant = dyn_cast<Constant>(GS.StoredOnceValue)) { | |||
| 1589 | if (GS.Ordering == AtomicOrdering::NotAtomic) { | |||
| 1590 | if (TryToShrinkGlobalToBoolean(GV, SOVConstant)) { | |||
| 1591 | ++NumShrunkToBool; | |||
| 1592 | return true; | |||
| 1593 | } | |||
| 1594 | } | |||
| 1595 | } | |||
| 1596 | } | |||
| 1597 | ||||
| 1598 | return Changed; | |||
| 1599 | } | |||
| 1600 | ||||
| 1601 | /// Analyze the specified global variable and optimize it if possible. If we | |||
| 1602 | /// make a change, return true. | |||
| 1603 | static bool | |||
| 1604 | processGlobal(GlobalValue &GV, | |||
| 1605 | function_ref<TargetLibraryInfo &(Function &)> GetTLI, | |||
| 1606 | function_ref<DominatorTree &(Function &)> LookupDomTree) { | |||
| 1607 | if (GV.getName().startswith("llvm.")) | |||
| 1608 | return false; | |||
| 1609 | ||||
| 1610 | GlobalStatus GS; | |||
| 1611 | ||||
| 1612 | if (GlobalStatus::analyzeGlobal(&GV, GS)) | |||
| 1613 | return false; | |||
| 1614 | ||||
| 1615 | bool Changed = false; | |||
| 1616 | if (!GS.IsCompared && !GV.hasGlobalUnnamedAddr()) { | |||
| 1617 | auto NewUnnamedAddr = GV.hasLocalLinkage() ? GlobalValue::UnnamedAddr::Global | |||
| 1618 | : GlobalValue::UnnamedAddr::Local; | |||
| 1619 | if (NewUnnamedAddr != GV.getUnnamedAddr()) { | |||
| 1620 | GV.setUnnamedAddr(NewUnnamedAddr); | |||
| 1621 | NumUnnamed++; | |||
| 1622 | Changed = true; | |||
| 1623 | } | |||
| 1624 | } | |||
| 1625 | ||||
| 1626 | // Do more involved optimizations if the global is internal. | |||
| 1627 | if (!GV.hasLocalLinkage()) | |||
| 1628 | return Changed; | |||
| 1629 | ||||
| 1630 | auto *GVar = dyn_cast<GlobalVariable>(&GV); | |||
| 1631 | if (!GVar) | |||
| 1632 | return Changed; | |||
| 1633 | ||||
| 1634 | if (GVar->isConstant() || !GVar->hasInitializer()) | |||
| 1635 | return Changed; | |||
| 1636 | ||||
| 1637 | return processInternalGlobal(GVar, GS, GetTLI, LookupDomTree) || Changed; | |||
| 1638 | } | |||
| 1639 | ||||
| 1640 | /// Walk all of the direct calls of the specified function, changing them to | |||
| 1641 | /// FastCC. | |||
| 1642 | static void ChangeCalleesToFastCall(Function *F) { | |||
| 1643 | for (User *U : F->users()) { | |||
| 1644 | if (isa<BlockAddress>(U)) | |||
| 1645 | continue; | |||
| 1646 | cast<CallBase>(U)->setCallingConv(CallingConv::Fast); | |||
| 1647 | } | |||
| 1648 | } | |||
| 1649 | ||||
| 1650 | static AttributeList StripAttr(LLVMContext &C, AttributeList Attrs, | |||
| 1651 | Attribute::AttrKind A) { | |||
| 1652 | unsigned AttrIndex; | |||
| 1653 | if (Attrs.hasAttrSomewhere(A, &AttrIndex)) | |||
| 1654 | return Attrs.removeAttribute(C, AttrIndex, A); | |||
| 1655 | return Attrs; | |||
| 1656 | } | |||
| 1657 | ||||
| 1658 | static void RemoveAttribute(Function *F, Attribute::AttrKind A) { | |||
| 1659 | F->setAttributes(StripAttr(F->getContext(), F->getAttributes(), A)); | |||
| 1660 | for (User *U : F->users()) { | |||
| 1661 | if (isa<BlockAddress>(U)) | |||
| 1662 | continue; | |||
| 1663 | CallBase *CB = cast<CallBase>(U); | |||
| 1664 | CB->setAttributes(StripAttr(F->getContext(), CB->getAttributes(), A)); | |||
| 1665 | } | |||
| 1666 | } | |||
| 1667 | ||||
| 1668 | /// Return true if this is a calling convention that we'd like to change. The | |||
| 1669 | /// idea here is that we don't want to mess with the convention if the user | |||
| 1670 | /// explicitly requested something with performance implications like coldcc, | |||
| 1671 | /// GHC, or anyregcc. | |||
| 1672 | static bool hasChangeableCC(Function *F) { | |||
| 1673 | CallingConv::ID CC = F->getCallingConv(); | |||
| 1674 | ||||
| 1675 | // FIXME: Is it worth transforming x86_stdcallcc and x86_fastcallcc? | |||
| 1676 | if (CC != CallingConv::C && CC != CallingConv::X86_ThisCall) | |||
| 1677 | return false; | |||
| 1678 | ||||
| 1679 | // FIXME: Change CC for the whole chain of musttail calls when possible. | |||
| 1680 | // | |||
| 1681 | // Can't change CC of the function that either has musttail calls, or is a | |||
| 1682 | // musttail callee itself | |||
| 1683 | for (User *U : F->users()) { | |||
| 1684 | if (isa<BlockAddress>(U)) | |||
| 1685 | continue; | |||
| 1686 | CallInst* CI = dyn_cast<CallInst>(U); | |||
| 1687 | if (!CI) | |||
| 1688 | continue; | |||
| 1689 | ||||
| 1690 | if (CI->isMustTailCall()) | |||
| 1691 | return false; | |||
| 1692 | } | |||
| 1693 | ||||
| 1694 | for (BasicBlock &BB : *F) | |||
| 1695 | if (BB.getTerminatingMustTailCall()) | |||
| 1696 | return false; | |||
| 1697 | ||||
| 1698 | return true; | |||
| 1699 | } | |||
| 1700 | ||||
| 1701 | /// Return true if the block containing the call site has a BlockFrequency of | |||
| 1702 | /// less than ColdCCRelFreq% of the entry block. | |||
| 1703 | static bool isColdCallSite(CallBase &CB, BlockFrequencyInfo &CallerBFI) { | |||
| 1704 | const BranchProbability ColdProb(ColdCCRelFreq, 100); | |||
| 1705 | auto *CallSiteBB = CB.getParent(); | |||
| 1706 | auto CallSiteFreq = CallerBFI.getBlockFreq(CallSiteBB); | |||
| 1707 | auto CallerEntryFreq = | |||
| 1708 | CallerBFI.getBlockFreq(&(CB.getCaller()->getEntryBlock())); | |||
| 1709 | return CallSiteFreq < CallerEntryFreq * ColdProb; | |||
| 1710 | } | |||
| 1711 | ||||
| 1712 | // This function checks if the input function F is cold at all call sites. It | |||
| 1713 | // also looks each call site's containing function, returning false if the | |||
| 1714 | // caller function contains other non cold calls. The input vector AllCallsCold | |||
| 1715 | // contains a list of functions that only have call sites in cold blocks. | |||
| 1716 | static bool | |||
| 1717 | isValidCandidateForColdCC(Function &F, | |||
| 1718 | function_ref<BlockFrequencyInfo &(Function &)> GetBFI, | |||
| 1719 | const std::vector<Function *> &AllCallsCold) { | |||
| 1720 | ||||
| 1721 | if (F.user_empty()) | |||
| 1722 | return false; | |||
| 1723 | ||||
| 1724 | for (User *U : F.users()) { | |||
| 1725 | if (isa<BlockAddress>(U)) | |||
| 1726 | continue; | |||
| 1727 | ||||
| 1728 | CallBase &CB = cast<CallBase>(*U); | |||
| 1729 | Function *CallerFunc = CB.getParent()->getParent(); | |||
| 1730 | BlockFrequencyInfo &CallerBFI = GetBFI(*CallerFunc); | |||
| 1731 | if (!isColdCallSite(CB, CallerBFI)) | |||
| 1732 | return false; | |||
| 1733 | if (!llvm::is_contained(AllCallsCold, CallerFunc)) | |||
| 1734 | return false; | |||
| 1735 | } | |||
| 1736 | return true; | |||
| 1737 | } | |||
| 1738 | ||||
| 1739 | static void changeCallSitesToColdCC(Function *F) { | |||
| 1740 | for (User *U : F->users()) { | |||
| 1741 | if (isa<BlockAddress>(U)) | |||
| 1742 | continue; | |||
| 1743 | cast<CallBase>(U)->setCallingConv(CallingConv::Cold); | |||
| 1744 | } | |||
| 1745 | } | |||
| 1746 | ||||
| 1747 | // This function iterates over all the call instructions in the input Function | |||
| 1748 | // and checks that all call sites are in cold blocks and are allowed to use the | |||
| 1749 | // coldcc calling convention. | |||
| 1750 | static bool | |||
| 1751 | hasOnlyColdCalls(Function &F, | |||
| 1752 | function_ref<BlockFrequencyInfo &(Function &)> GetBFI) { | |||
| 1753 | for (BasicBlock &BB : F) { | |||
| 1754 | for (Instruction &I : BB) { | |||
| 1755 | if (CallInst *CI = dyn_cast<CallInst>(&I)) { | |||
| 1756 | // Skip over isline asm instructions since they aren't function calls. | |||
| 1757 | if (CI->isInlineAsm()) | |||
| 1758 | continue; | |||
| 1759 | Function *CalledFn = CI->getCalledFunction(); | |||
| 1760 | if (!CalledFn) | |||
| 1761 | return false; | |||
| 1762 | if (!CalledFn->hasLocalLinkage()) | |||
| 1763 | return false; | |||
| 1764 | // Skip over instrinsics since they won't remain as function calls. | |||
| 1765 | if (CalledFn->getIntrinsicID() != Intrinsic::not_intrinsic) | |||
| 1766 | continue; | |||
| 1767 | // Check if it's valid to use coldcc calling convention. | |||
| 1768 | if (!hasChangeableCC(CalledFn) || CalledFn->isVarArg() || | |||
| 1769 | CalledFn->hasAddressTaken()) | |||
| 1770 | return false; | |||
| 1771 | BlockFrequencyInfo &CallerBFI = GetBFI(F); | |||
| 1772 | if (!isColdCallSite(*CI, CallerBFI)) | |||
| 1773 | return false; | |||
| 1774 | } | |||
| 1775 | } | |||
| 1776 | } | |||
| 1777 | return true; | |||
| 1778 | } | |||
| 1779 | ||||
| 1780 | static bool hasMustTailCallers(Function *F) { | |||
| 1781 | for (User *U : F->users()) { | |||
| 1782 | CallBase *CB = dyn_cast<CallBase>(U); | |||
| 1783 | if (!CB) { | |||
| 1784 | assert(isa<BlockAddress>(U) &&((void)0) | |||
| 1785 | "Expected either CallBase or BlockAddress")((void)0); | |||
| 1786 | continue; | |||
| 1787 | } | |||
| 1788 | if (CB->isMustTailCall()) | |||
| 1789 | return true; | |||
| 1790 | } | |||
| 1791 | return false; | |||
| 1792 | } | |||
| 1793 | ||||
| 1794 | static bool hasInvokeCallers(Function *F) { | |||
| 1795 | for (User *U : F->users()) | |||
| 1796 | if (isa<InvokeInst>(U)) | |||
| 1797 | return true; | |||
| 1798 | return false; | |||
| 1799 | } | |||
| 1800 | ||||
| 1801 | static void RemovePreallocated(Function *F) { | |||
| 1802 | RemoveAttribute(F, Attribute::Preallocated); | |||
| 1803 | ||||
| 1804 | auto *M = F->getParent(); | |||
| 1805 | ||||
| 1806 | IRBuilder<> Builder(M->getContext()); | |||
| 1807 | ||||
| 1808 | // Cannot modify users() while iterating over it, so make a copy. | |||
| 1809 | SmallVector<User *, 4> PreallocatedCalls(F->users()); | |||
| 1810 | for (User *U : PreallocatedCalls) { | |||
| 1811 | CallBase *CB = dyn_cast<CallBase>(U); | |||
| 1812 | if (!CB) | |||
| 1813 | continue; | |||
| 1814 | ||||
| 1815 | assert(((void)0) | |||
| 1816 | !CB->isMustTailCall() &&((void)0) | |||
| 1817 | "Shouldn't call RemotePreallocated() on a musttail preallocated call")((void)0); | |||
| 1818 | // Create copy of call without "preallocated" operand bundle. | |||
| 1819 | SmallVector<OperandBundleDef, 1> OpBundles; | |||
| 1820 | CB->getOperandBundlesAsDefs(OpBundles); | |||
| 1821 | CallBase *PreallocatedSetup = nullptr; | |||
| 1822 | for (auto *It = OpBundles.begin(); It != OpBundles.end(); ++It) { | |||
| 1823 | if (It->getTag() == "preallocated") { | |||
| 1824 | PreallocatedSetup = cast<CallBase>(*It->input_begin()); | |||
| 1825 | OpBundles.erase(It); | |||
| 1826 | break; | |||
| 1827 | } | |||
| 1828 | } | |||
| 1829 | assert(PreallocatedSetup && "Did not find preallocated bundle")((void)0); | |||
| 1830 | uint64_t ArgCount = | |||
| 1831 | cast<ConstantInt>(PreallocatedSetup->getArgOperand(0))->getZExtValue(); | |||
| 1832 | ||||
| 1833 | assert((isa<CallInst>(CB) || isa<InvokeInst>(CB)) &&((void)0) | |||
| 1834 | "Unknown indirect call type")((void)0); | |||
| 1835 | CallBase *NewCB = CallBase::Create(CB, OpBundles, CB); | |||
| 1836 | CB->replaceAllUsesWith(NewCB); | |||
| 1837 | NewCB->takeName(CB); | |||
| 1838 | CB->eraseFromParent(); | |||
| 1839 | ||||
| 1840 | Builder.SetInsertPoint(PreallocatedSetup); | |||
| 1841 | auto *StackSave = | |||
| 1842 | Builder.CreateCall(Intrinsic::getDeclaration(M, Intrinsic::stacksave)); | |||
| 1843 | ||||
| 1844 | Builder.SetInsertPoint(NewCB->getNextNonDebugInstruction()); | |||
| 1845 | Builder.CreateCall(Intrinsic::getDeclaration(M, Intrinsic::stackrestore), | |||
| 1846 | StackSave); | |||
| 1847 | ||||
| 1848 | // Replace @llvm.call.preallocated.arg() with alloca. | |||
| 1849 | // Cannot modify users() while iterating over it, so make a copy. | |||
| 1850 | // @llvm.call.preallocated.arg() can be called with the same index multiple | |||
| 1851 | // times. So for each @llvm.call.preallocated.arg(), we see if we have | |||
| 1852 | // already created a Value* for the index, and if not, create an alloca and | |||
| 1853 | // bitcast right after the @llvm.call.preallocated.setup() so that it | |||
| 1854 | // dominates all uses. | |||
| 1855 | SmallVector<Value *, 2> ArgAllocas(ArgCount); | |||
| 1856 | SmallVector<User *, 2> PreallocatedArgs(PreallocatedSetup->users()); | |||
| 1857 | for (auto *User : PreallocatedArgs) { | |||
| 1858 | auto *UseCall = cast<CallBase>(User); | |||
| 1859 | assert(UseCall->getCalledFunction()->getIntrinsicID() ==((void)0) | |||
| 1860 | Intrinsic::call_preallocated_arg &&((void)0) | |||
| 1861 | "preallocated token use was not a llvm.call.preallocated.arg")((void)0); | |||
| 1862 | uint64_t AllocArgIndex = | |||
| 1863 | cast<ConstantInt>(UseCall->getArgOperand(1))->getZExtValue(); | |||
| 1864 | Value *AllocaReplacement = ArgAllocas[AllocArgIndex]; | |||
| 1865 | if (!AllocaReplacement) { | |||
| 1866 | auto AddressSpace = UseCall->getType()->getPointerAddressSpace(); | |||
| 1867 | auto *ArgType = UseCall | |||
| 1868 | ->getAttribute(AttributeList::FunctionIndex, | |||
| 1869 | Attribute::Preallocated) | |||
| 1870 | .getValueAsType(); | |||
| 1871 | auto *InsertBefore = PreallocatedSetup->getNextNonDebugInstruction(); | |||
| 1872 | Builder.SetInsertPoint(InsertBefore); | |||
| 1873 | auto *Alloca = | |||
| 1874 | Builder.CreateAlloca(ArgType, AddressSpace, nullptr, "paarg"); | |||
| 1875 | auto *BitCast = Builder.CreateBitCast( | |||
| 1876 | Alloca, Type::getInt8PtrTy(M->getContext()), UseCall->getName()); | |||
| 1877 | ArgAllocas[AllocArgIndex] = BitCast; | |||
| 1878 | AllocaReplacement = BitCast; | |||
| 1879 | } | |||
| 1880 | ||||
| 1881 | UseCall->replaceAllUsesWith(AllocaReplacement); | |||
| 1882 | UseCall->eraseFromParent(); | |||
| 1883 | } | |||
| 1884 | // Remove @llvm.call.preallocated.setup(). | |||
| 1885 | cast<Instruction>(PreallocatedSetup)->eraseFromParent(); | |||
| 1886 | } | |||
| 1887 | } | |||
| 1888 | ||||
| 1889 | static bool | |||
| 1890 | OptimizeFunctions(Module &M, | |||
| 1891 | function_ref<TargetLibraryInfo &(Function &)> GetTLI, | |||
| 1892 | function_ref<TargetTransformInfo &(Function &)> GetTTI, | |||
| 1893 | function_ref<BlockFrequencyInfo &(Function &)> GetBFI, | |||
| 1894 | function_ref<DominatorTree &(Function &)> LookupDomTree, | |||
| 1895 | SmallPtrSetImpl<const Comdat *> &NotDiscardableComdats) { | |||
| 1896 | ||||
| 1897 | bool Changed = false; | |||
| 1898 | ||||
| 1899 | std::vector<Function *> AllCallsCold; | |||
| 1900 | for (Module::iterator FI = M.begin(), E = M.end(); FI != E;) { | |||
| 1901 | Function *F = &*FI++; | |||
| 1902 | if (hasOnlyColdCalls(*F, GetBFI)) | |||
| 1903 | AllCallsCold.push_back(F); | |||
| 1904 | } | |||
| 1905 | ||||
| 1906 | // Optimize functions. | |||
| 1907 | for (Module::iterator FI = M.begin(), E = M.end(); FI != E; ) { | |||
| 1908 | Function *F = &*FI++; | |||
| 1909 | ||||
| 1910 | // Don't perform global opt pass on naked functions; we don't want fast | |||
| 1911 | // calling conventions for naked functions. | |||
| 1912 | if (F->hasFnAttribute(Attribute::Naked)) | |||
| 1913 | continue; | |||
| 1914 | ||||
| 1915 | // Functions without names cannot be referenced outside this module. | |||
| 1916 | if (!F->hasName() && !F->isDeclaration() && !F->hasLocalLinkage()) | |||
| 1917 | F->setLinkage(GlobalValue::InternalLinkage); | |||
| 1918 | ||||
| 1919 | if (deleteIfDead(*F, NotDiscardableComdats)) { | |||
| 1920 | Changed = true; | |||
| 1921 | continue; | |||
| 1922 | } | |||
| 1923 | ||||
| 1924 | // LLVM's definition of dominance allows instructions that are cyclic | |||
| 1925 | // in unreachable blocks, e.g.: | |||
| 1926 | // %pat = select i1 %condition, @global, i16* %pat | |||
| 1927 | // because any instruction dominates an instruction in a block that's | |||
| 1928 | // not reachable from entry. | |||
| 1929 | // So, remove unreachable blocks from the function, because a) there's | |||
| 1930 | // no point in analyzing them and b) GlobalOpt should otherwise grow | |||
| 1931 | // some more complicated logic to break these cycles. | |||
| 1932 | // Removing unreachable blocks might invalidate the dominator so we | |||
| 1933 | // recalculate it. | |||
| 1934 | if (!F->isDeclaration()) { | |||
| 1935 | if (removeUnreachableBlocks(*F)) { | |||
| 1936 | auto &DT = LookupDomTree(*F); | |||
| 1937 | DT.recalculate(*F); | |||
| 1938 | Changed = true; | |||
| 1939 | } | |||
| 1940 | } | |||
| 1941 | ||||
| 1942 | Changed |= processGlobal(*F, GetTLI, LookupDomTree); | |||
| 1943 | ||||
| 1944 | if (!F->hasLocalLinkage()) | |||
| 1945 | continue; | |||
| 1946 | ||||
| 1947 | // If we have an inalloca parameter that we can safely remove the | |||
| 1948 | // inalloca attribute from, do so. This unlocks optimizations that | |||
| 1949 | // wouldn't be safe in the presence of inalloca. | |||
| 1950 | // FIXME: We should also hoist alloca affected by this to the entry | |||
| 1951 | // block if possible. | |||
| 1952 | if (F->getAttributes().hasAttrSomewhere(Attribute::InAlloca) && | |||
| 1953 | !F->hasAddressTaken() && !hasMustTailCallers(F)) { | |||
| 1954 | RemoveAttribute(F, Attribute::InAlloca); | |||
| 1955 | Changed = true; | |||
| 1956 | } | |||
| 1957 | ||||
| 1958 | // FIXME: handle invokes | |||
| 1959 | // FIXME: handle musttail | |||
| 1960 | if (F->getAttributes().hasAttrSomewhere(Attribute::Preallocated)) { | |||
| 1961 | if (!F->hasAddressTaken() && !hasMustTailCallers(F) && | |||
| 1962 | !hasInvokeCallers(F)) { | |||
| 1963 | RemovePreallocated(F); | |||
| 1964 | Changed = true; | |||
| 1965 | } | |||
| 1966 | continue; | |||
| 1967 | } | |||
| 1968 | ||||
| 1969 | if (hasChangeableCC(F) && !F->isVarArg() && !F->hasAddressTaken()) { | |||
| 1970 | NumInternalFunc++; | |||
| 1971 | TargetTransformInfo &TTI = GetTTI(*F); | |||
| 1972 | // Change the calling convention to coldcc if either stress testing is | |||
| 1973 | // enabled or the target would like to use coldcc on functions which are | |||
| 1974 | // cold at all call sites and the callers contain no other non coldcc | |||
| 1975 | // calls. | |||
| 1976 | if (EnableColdCCStressTest || | |||
| 1977 | (TTI.useColdCCForColdCall(*F) && | |||
| 1978 | isValidCandidateForColdCC(*F, GetBFI, AllCallsCold))) { | |||
| 1979 | F->setCallingConv(CallingConv::Cold); | |||
| 1980 | changeCallSitesToColdCC(F); | |||
| 1981 | Changed = true; | |||
| 1982 | NumColdCC++; | |||
| 1983 | } | |||
| 1984 | } | |||
| 1985 | ||||
| 1986 | if (hasChangeableCC(F) && !F->isVarArg() && | |||
| 1987 | !F->hasAddressTaken()) { | |||
| 1988 | // If this function has a calling convention worth changing, is not a | |||
| 1989 | // varargs function, and is only called directly, promote it to use the | |||
| 1990 | // Fast calling convention. | |||
| 1991 | F->setCallingConv(CallingConv::Fast); | |||
| 1992 | ChangeCalleesToFastCall(F); | |||
| 1993 | ++NumFastCallFns; | |||
| 1994 | Changed = true; | |||
| 1995 | } | |||
| 1996 | ||||
| 1997 | if (F->getAttributes().hasAttrSomewhere(Attribute::Nest) && | |||
| 1998 | !F->hasAddressTaken()) { | |||
| 1999 | // The function is not used by a trampoline intrinsic, so it is safe | |||
| 2000 | // to remove the 'nest' attribute. | |||
| 2001 | RemoveAttribute(F, Attribute::Nest); | |||
| 2002 | ++NumNestRemoved; | |||
| 2003 | Changed = true; | |||
| 2004 | } | |||
| 2005 | } | |||
| 2006 | return Changed; | |||
| 2007 | } | |||
| 2008 | ||||
| 2009 | static bool | |||
| 2010 | OptimizeGlobalVars(Module &M, | |||
| 2011 | function_ref<TargetLibraryInfo &(Function &)> GetTLI, | |||
| 2012 | function_ref<DominatorTree &(Function &)> LookupDomTree, | |||
| 2013 | SmallPtrSetImpl<const Comdat *> &NotDiscardableComdats) { | |||
| 2014 | bool Changed = false; | |||
| 2015 | ||||
| 2016 | for (Module::global_iterator GVI = M.global_begin(), E = M.global_end(); | |||
| 2017 | GVI != E; ) { | |||
| 2018 | GlobalVariable *GV = &*GVI++; | |||
| 2019 | // Global variables without names cannot be referenced outside this module. | |||
| 2020 | if (!GV->hasName() && !GV->isDeclaration() && !GV->hasLocalLinkage()) | |||
| 2021 | GV->setLinkage(GlobalValue::InternalLinkage); | |||
| 2022 | // Simplify the initializer. | |||
| 2023 | if (GV->hasInitializer()) | |||
| 2024 | if (auto *C = dyn_cast<Constant>(GV->getInitializer())) { | |||
| 2025 | auto &DL = M.getDataLayout(); | |||
| 2026 | // TLI is not used in the case of a Constant, so use default nullptr | |||
| 2027 | // for that optional parameter, since we don't have a Function to | |||
| 2028 | // provide GetTLI anyway. | |||
| 2029 | Constant *New = ConstantFoldConstant(C, DL, /*TLI*/ nullptr); | |||
| 2030 | if (New != C) | |||
| 2031 | GV->setInitializer(New); | |||
| 2032 | } | |||
| 2033 | ||||
| 2034 | if (deleteIfDead(*GV, NotDiscardableComdats)) { | |||
| 2035 | Changed = true; | |||
| 2036 | continue; | |||
| 2037 | } | |||
| 2038 | ||||
| 2039 | Changed |= processGlobal(*GV, GetTLI, LookupDomTree); | |||
| 2040 | } | |||
| 2041 | return Changed; | |||
| 2042 | } | |||
| 2043 | ||||
| 2044 | /// Evaluate a piece of a constantexpr store into a global initializer. This | |||
| 2045 | /// returns 'Init' modified to reflect 'Val' stored into it. At this point, the | |||
| 2046 | /// GEP operands of Addr [0, OpNo) have been stepped into. | |||
| 2047 | static Constant *EvaluateStoreInto(Constant *Init, Constant *Val, | |||
| 2048 | ConstantExpr *Addr, unsigned OpNo) { | |||
| 2049 | // Base case of the recursion. | |||
| 2050 | if (OpNo == Addr->getNumOperands()) { | |||
| 2051 | assert(Val->getType() == Init->getType() && "Type mismatch!")((void)0); | |||
| 2052 | return Val; | |||
| 2053 | } | |||
| 2054 | ||||
| 2055 | SmallVector<Constant*, 32> Elts; | |||
| 2056 | if (StructType *STy = dyn_cast<StructType>(Init->getType())) { | |||
| 2057 | // Break up the constant into its elements. | |||
| 2058 | for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) | |||
| 2059 | Elts.push_back(Init->getAggregateElement(i)); | |||
| 2060 | ||||
| 2061 | // Replace the element that we are supposed to. | |||
| 2062 | ConstantInt *CU = cast<ConstantInt>(Addr->getOperand(OpNo)); | |||
| 2063 | unsigned Idx = CU->getZExtValue(); | |||
| 2064 | assert(Idx < STy->getNumElements() && "Struct index out of range!")((void)0); | |||
| 2065 | Elts[Idx] = EvaluateStoreInto(Elts[Idx], Val, Addr, OpNo+1); | |||
| 2066 | ||||
| 2067 | // Return the modified struct. | |||
| 2068 | return ConstantStruct::get(STy, Elts); | |||
| 2069 | } | |||
| 2070 | ||||
| 2071 | ConstantInt *CI = cast<ConstantInt>(Addr->getOperand(OpNo)); | |||
| 2072 | uint64_t NumElts; | |||
| 2073 | if (ArrayType *ATy = dyn_cast<ArrayType>(Init->getType())) | |||
| 2074 | NumElts = ATy->getNumElements(); | |||
| 2075 | else | |||
| 2076 | NumElts = cast<FixedVectorType>(Init->getType())->getNumElements(); | |||
| 2077 | ||||
| 2078 | // Break up the array into elements. | |||
| 2079 | for (uint64_t i = 0, e = NumElts; i != e; ++i) | |||
| 2080 | Elts.push_back(Init->getAggregateElement(i)); | |||
| 2081 | ||||
| 2082 | assert(CI->getZExtValue() < NumElts)((void)0); | |||
| 2083 | Elts[CI->getZExtValue()] = | |||
| 2084 | EvaluateStoreInto(Elts[CI->getZExtValue()], Val, Addr, OpNo+1); | |||
| 2085 | ||||
| 2086 | if (Init->getType()->isArrayTy()) | |||
| 2087 | return ConstantArray::get(cast<ArrayType>(Init->getType()), Elts); | |||
| 2088 | return ConstantVector::get(Elts); | |||
| 2089 | } | |||
| 2090 | ||||
| 2091 | /// We have decided that Addr (which satisfies the predicate | |||
| 2092 | /// isSimpleEnoughPointerToCommit) should get Val as its value. Make it happen. | |||
| 2093 | static void CommitValueTo(Constant *Val, Constant *Addr) { | |||
| 2094 | if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) { | |||
| 2095 | assert(GV->hasInitializer())((void)0); | |||
| 2096 | GV->setInitializer(Val); | |||
| 2097 | return; | |||
| 2098 | } | |||
| 2099 | ||||
| 2100 | ConstantExpr *CE = cast<ConstantExpr>(Addr); | |||
| 2101 | GlobalVariable *GV = cast<GlobalVariable>(CE->getOperand(0)); | |||
| 2102 | GV->setInitializer(EvaluateStoreInto(GV->getInitializer(), Val, CE, 2)); | |||
| 2103 | } | |||
| 2104 | ||||
| 2105 | /// Given a map of address -> value, where addresses are expected to be some form | |||
| 2106 | /// of either a global or a constant GEP, set the initializer for the address to | |||
| 2107 | /// be the value. This performs mostly the same function as CommitValueTo() | |||
| 2108 | /// and EvaluateStoreInto() but is optimized to be more efficient for the common | |||
| 2109 | /// case where the set of addresses are GEPs sharing the same underlying global, | |||
| 2110 | /// processing the GEPs in batches rather than individually. | |||
| 2111 | /// | |||
| 2112 | /// To give an example, consider the following C++ code adapted from the clang | |||
| 2113 | /// regression tests: | |||
| 2114 | /// struct S { | |||
| 2115 | /// int n = 10; | |||
| 2116 | /// int m = 2 * n; | |||
| 2117 | /// S(int a) : n(a) {} | |||
| 2118 | /// }; | |||
| 2119 | /// | |||
| 2120 | /// template<typename T> | |||
| 2121 | /// struct U { | |||
| 2122 | /// T *r = &q; | |||
| 2123 | /// T q = 42; | |||
| 2124 | /// U *p = this; | |||
| 2125 | /// }; | |||
| 2126 | /// | |||
| 2127 | /// U<S> e; | |||
| 2128 | /// | |||
| 2129 | /// The global static constructor for 'e' will need to initialize 'r' and 'p' of | |||
| 2130 | /// the outer struct, while also initializing the inner 'q' structs 'n' and 'm' | |||
| 2131 | /// members. This batch algorithm will simply use general CommitValueTo() method | |||
| 2132 | /// to handle the complex nested S struct initialization of 'q', before | |||
| 2133 | /// processing the outermost members in a single batch. Using CommitValueTo() to | |||
| 2134 | /// handle member in the outer struct is inefficient when the struct/array is | |||
| 2135 | /// very large as we end up creating and destroy constant arrays for each | |||
| 2136 | /// initialization. | |||
| 2137 | /// For the above case, we expect the following IR to be generated: | |||
| 2138 | /// | |||
| 2139 | /// %struct.U = type { %struct.S*, %struct.S, %struct.U* } | |||
| 2140 | /// %struct.S = type { i32, i32 } | |||
| 2141 | /// @e = global %struct.U { %struct.S* gep inbounds (%struct.U, %struct.U* @e, | |||
| 2142 | /// i64 0, i32 1), | |||
| 2143 | /// %struct.S { i32 42, i32 84 }, %struct.U* @e } | |||
| 2144 | /// The %struct.S { i32 42, i32 84 } inner initializer is treated as a complex | |||
| 2145 | /// constant expression, while the other two elements of @e are "simple". | |||
| 2146 | static void BatchCommitValueTo(const DenseMap<Constant*, Constant*> &Mem) { | |||
| 2147 | SmallVector<std::pair<GlobalVariable*, Constant*>, 32> GVs; | |||
| 2148 | SmallVector<std::pair<ConstantExpr*, Constant*>, 32> ComplexCEs; | |||
| 2149 | SmallVector<std::pair<ConstantExpr*, Constant*>, 32> SimpleCEs; | |||
| 2150 | SimpleCEs.reserve(Mem.size()); | |||
| 2151 | ||||
| 2152 | for (const auto &I : Mem) { | |||
| 2153 | if (auto *GV = dyn_cast<GlobalVariable>(I.first)) { | |||
| 2154 | GVs.push_back(std::make_pair(GV, I.second)); | |||
| 2155 | } else { | |||
| 2156 | ConstantExpr *GEP = cast<ConstantExpr>(I.first); | |||
| 2157 | // We don't handle the deeply recursive case using the batch method. | |||
| 2158 | if (GEP->getNumOperands() > 3) | |||
| 2159 | ComplexCEs.push_back(std::make_pair(GEP, I.second)); | |||
| 2160 | else | |||
| 2161 | SimpleCEs.push_back(std::make_pair(GEP, I.second)); | |||
| 2162 | } | |||
| 2163 | } | |||
| 2164 | ||||
| 2165 | // The algorithm below doesn't handle cases like nested structs, so use the | |||
| 2166 | // slower fully general method if we have to. | |||
| 2167 | for (auto ComplexCE : ComplexCEs) | |||
| 2168 | CommitValueTo(ComplexCE.second, ComplexCE.first); | |||
| 2169 | ||||
| 2170 | for (auto GVPair : GVs) { | |||
| 2171 | assert(GVPair.first->hasInitializer())((void)0); | |||
| 2172 | GVPair.first->setInitializer(GVPair.second); | |||
| 2173 | } | |||
| 2174 | ||||
| 2175 | if (SimpleCEs.empty()) | |||
| 2176 | return; | |||
| 2177 | ||||
| 2178 | // We cache a single global's initializer elements in the case where the | |||
| 2179 | // subsequent address/val pair uses the same one. This avoids throwing away and | |||
| 2180 | // rebuilding the constant struct/vector/array just because one element is | |||
| 2181 | // modified at a time. | |||
| 2182 | SmallVector<Constant *, 32> Elts; | |||
| 2183 | Elts.reserve(SimpleCEs.size()); | |||
| 2184 | GlobalVariable *CurrentGV = nullptr; | |||
| 2185 | ||||
| 2186 | auto commitAndSetupCache = [&](GlobalVariable *GV, bool Update) { | |||
| 2187 | Constant *Init = GV->getInitializer(); | |||
| ||||
| 2188 | Type *Ty = Init->getType(); | |||
| 2189 | if (Update) { | |||
| 2190 | if (CurrentGV) { | |||
| 2191 | assert(CurrentGV && "Expected a GV to commit to!")((void)0); | |||
| 2192 | Type *CurrentInitTy = CurrentGV->getInitializer()->getType(); | |||
| 2193 | // We have a valid cache that needs to be committed. | |||
| 2194 | if (StructType *STy = dyn_cast<StructType>(CurrentInitTy)) | |||
| 2195 | CurrentGV->setInitializer(ConstantStruct::get(STy, Elts)); | |||
| 2196 | else if (ArrayType *ArrTy = dyn_cast<ArrayType>(CurrentInitTy)) | |||
| 2197 | CurrentGV->setInitializer(ConstantArray::get(ArrTy, Elts)); | |||
| 2198 | else | |||
| 2199 | CurrentGV->setInitializer(ConstantVector::get(Elts)); | |||
| 2200 | } | |||
| 2201 | if (CurrentGV == GV) | |||
| 2202 | return; | |||
| 2203 | // Need to clear and set up cache for new initializer. | |||
| 2204 | CurrentGV = GV; | |||
| 2205 | Elts.clear(); | |||
| 2206 | unsigned NumElts; | |||
| 2207 | if (auto *STy = dyn_cast<StructType>(Ty)) | |||
| 2208 | NumElts = STy->getNumElements(); | |||
| 2209 | else if (auto *ATy = dyn_cast<ArrayType>(Ty)) | |||
| 2210 | NumElts = ATy->getNumElements(); | |||
| 2211 | else | |||
| 2212 | NumElts = cast<FixedVectorType>(Ty)->getNumElements(); | |||
| 2213 | for (unsigned i = 0, e = NumElts; i != e; ++i) | |||
| 2214 | Elts.push_back(Init->getAggregateElement(i)); | |||
| 2215 | } | |||
| 2216 | }; | |||
| 2217 | ||||
| 2218 | for (auto CEPair : SimpleCEs) { | |||
| 2219 | ConstantExpr *GEP = CEPair.first; | |||
| 2220 | Constant *Val = CEPair.second; | |||
| 2221 | ||||
| 2222 | GlobalVariable *GV = cast<GlobalVariable>(GEP->getOperand(0)); | |||
| 2223 | commitAndSetupCache(GV, GV != CurrentGV); | |||
| 2224 | ConstantInt *CI = cast<ConstantInt>(GEP->getOperand(2)); | |||
| 2225 | Elts[CI->getZExtValue()] = Val; | |||
| 2226 | } | |||
| 2227 | // The last initializer in the list needs to be committed, others | |||
| 2228 | // will be committed on a new initializer being processed. | |||
| 2229 | commitAndSetupCache(CurrentGV, true); | |||
| 2230 | } | |||
| 2231 | ||||
| 2232 | /// Evaluate static constructors in the function, if we can. Return true if we | |||
| 2233 | /// can, false otherwise. | |||
| 2234 | static bool EvaluateStaticConstructor(Function *F, const DataLayout &DL, | |||
| 2235 | TargetLibraryInfo *TLI) { | |||
| 2236 | // Call the function. | |||
| 2237 | Evaluator Eval(DL, TLI); | |||
| 2238 | Constant *RetValDummy; | |||
| 2239 | bool EvalSuccess = Eval.EvaluateFunction(F, RetValDummy, | |||
| 2240 | SmallVector<Constant*, 0>()); | |||
| 2241 | ||||
| 2242 | if (EvalSuccess) { | |||
| 2243 | ++NumCtorsEvaluated; | |||
| 2244 | ||||
| 2245 | // We succeeded at evaluation: commit the result. | |||
| 2246 | LLVM_DEBUG(dbgs() << "FULLY EVALUATED GLOBAL CTOR FUNCTION '"do { } while (false) | |||
| 2247 | << F->getName() << "' to "do { } while (false) | |||
| 2248 | << Eval.getMutatedMemory().size() << " stores.\n")do { } while (false); | |||
| 2249 | BatchCommitValueTo(Eval.getMutatedMemory()); | |||
| 2250 | for (GlobalVariable *GV : Eval.getInvariants()) | |||
| 2251 | GV->setConstant(true); | |||
| 2252 | } | |||
| 2253 | ||||
| 2254 | return EvalSuccess; | |||
| 2255 | } | |||
| 2256 | ||||
| 2257 | static int compareNames(Constant *const *A, Constant *const *B) { | |||
| 2258 | Value *AStripped = (*A)->stripPointerCasts(); | |||
| 2259 | Value *BStripped = (*B)->stripPointerCasts(); | |||
| 2260 | return AStripped->getName().compare(BStripped->getName()); | |||
| 2261 | } | |||
| 2262 | ||||
| 2263 | static void setUsedInitializer(GlobalVariable &V, | |||
| 2264 | const SmallPtrSetImpl<GlobalValue *> &Init) { | |||
| 2265 | if (Init.empty()) { | |||
| 2266 | V.eraseFromParent(); | |||
| 2267 | return; | |||
| 2268 | } | |||
| 2269 | ||||
| 2270 | // Type of pointer to the array of pointers. | |||
| 2271 | PointerType *Int8PtrTy = Type::getInt8PtrTy(V.getContext(), 0); | |||
| 2272 | ||||
| 2273 | SmallVector<Constant *, 8> UsedArray; | |||
| 2274 | for (GlobalValue *GV : Init) { | |||
| 2275 | Constant *Cast | |||
| 2276 | = ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, Int8PtrTy); | |||
| 2277 | UsedArray.push_back(Cast); | |||
| 2278 | } | |||
| 2279 | // Sort to get deterministic order. | |||
| 2280 | array_pod_sort(UsedArray.begin(), UsedArray.end(), compareNames); | |||
| 2281 | ArrayType *ATy = ArrayType::get(Int8PtrTy, UsedArray.size()); | |||
| 2282 | ||||
| 2283 | Module *M = V.getParent(); | |||
| 2284 | V.removeFromParent(); | |||
| 2285 | GlobalVariable *NV = | |||
| 2286 | new GlobalVariable(*M, ATy, false, GlobalValue::AppendingLinkage, | |||
| 2287 | ConstantArray::get(ATy, UsedArray), ""); | |||
| 2288 | NV->takeName(&V); | |||
| 2289 | NV->setSection("llvm.metadata"); | |||
| 2290 | delete &V; | |||
| 2291 | } | |||
| 2292 | ||||
| 2293 | namespace { | |||
| 2294 | ||||
| 2295 | /// An easy to access representation of llvm.used and llvm.compiler.used. | |||
| 2296 | class LLVMUsed { | |||
| 2297 | SmallPtrSet<GlobalValue *, 4> Used; | |||
| 2298 | SmallPtrSet<GlobalValue *, 4> CompilerUsed; | |||
| 2299 | GlobalVariable *UsedV; | |||
| 2300 | GlobalVariable *CompilerUsedV; | |||
| 2301 | ||||
| 2302 | public: | |||
| 2303 | LLVMUsed(Module &M) { | |||
| 2304 | SmallVector<GlobalValue *, 4> Vec; | |||
| 2305 | UsedV = collectUsedGlobalVariables(M, Vec, false); | |||
| 2306 | Used = {Vec.begin(), Vec.end()}; | |||
| 2307 | Vec.clear(); | |||
| 2308 | CompilerUsedV = collectUsedGlobalVariables(M, Vec, true); | |||
| 2309 | CompilerUsed = {Vec.begin(), Vec.end()}; | |||
| 2310 | } | |||
| 2311 | ||||
| 2312 | using iterator = SmallPtrSet<GlobalValue *, 4>::iterator; | |||
| 2313 | using used_iterator_range = iterator_range<iterator>; | |||
| 2314 | ||||
| 2315 | iterator usedBegin() { return Used.begin(); } | |||
| 2316 | iterator usedEnd() { return Used.end(); } | |||
| 2317 | ||||
| 2318 | used_iterator_range used() { | |||
| 2319 | return used_iterator_range(usedBegin(), usedEnd()); | |||
| 2320 | } | |||
| 2321 | ||||
| 2322 | iterator compilerUsedBegin() { return CompilerUsed.begin(); } | |||
| 2323 | iterator compilerUsedEnd() { return CompilerUsed.end(); } | |||
| 2324 | ||||
| 2325 | used_iterator_range compilerUsed() { | |||
| 2326 | return used_iterator_range(compilerUsedBegin(), compilerUsedEnd()); | |||
| 2327 | } | |||
| 2328 | ||||
| 2329 | bool usedCount(GlobalValue *GV) const { return Used.count(GV); } | |||
| 2330 | ||||
| 2331 | bool compilerUsedCount(GlobalValue *GV) const { | |||
| 2332 | return CompilerUsed.count(GV); | |||
| 2333 | } | |||
| 2334 | ||||
| 2335 | bool usedErase(GlobalValue *GV) { return Used.erase(GV); } | |||
| 2336 | bool compilerUsedErase(GlobalValue *GV) { return CompilerUsed.erase(GV); } | |||
| 2337 | bool usedInsert(GlobalValue *GV) { return Used.insert(GV).second; } | |||
| 2338 | ||||
| 2339 | bool compilerUsedInsert(GlobalValue *GV) { | |||
| 2340 | return CompilerUsed.insert(GV).second; | |||
| 2341 | } | |||
| 2342 | ||||
| 2343 | void syncVariablesAndSets() { | |||
| 2344 | if (UsedV) | |||
| 2345 | setUsedInitializer(*UsedV, Used); | |||
| 2346 | if (CompilerUsedV) | |||
| 2347 | setUsedInitializer(*CompilerUsedV, CompilerUsed); | |||
| 2348 | } | |||
| 2349 | }; | |||
| 2350 | ||||
| 2351 | } // end anonymous namespace | |||
| 2352 | ||||
| 2353 | static bool hasUseOtherThanLLVMUsed(GlobalAlias &GA, const LLVMUsed &U) { | |||
| 2354 | if (GA.use_empty()) // No use at all. | |||
| 2355 | return false; | |||
| 2356 | ||||
| 2357 | assert((!U.usedCount(&GA) || !U.compilerUsedCount(&GA)) &&((void)0) | |||
| 2358 | "We should have removed the duplicated "((void)0) | |||
| 2359 | "element from llvm.compiler.used")((void)0); | |||
| 2360 | if (!GA.hasOneUse()) | |||
| 2361 | // Strictly more than one use. So at least one is not in llvm.used and | |||
| 2362 | // llvm.compiler.used. | |||
| 2363 | return true; | |||
| 2364 | ||||
| 2365 | // Exactly one use. Check if it is in llvm.used or llvm.compiler.used. | |||
| 2366 | return !U.usedCount(&GA) && !U.compilerUsedCount(&GA); | |||
| 2367 | } | |||
| 2368 | ||||
| 2369 | static bool hasMoreThanOneUseOtherThanLLVMUsed(GlobalValue &V, | |||
| 2370 | const LLVMUsed &U) { | |||
| 2371 | unsigned N = 2; | |||
| 2372 | assert((!U.usedCount(&V) || !U.compilerUsedCount(&V)) &&((void)0) | |||
| 2373 | "We should have removed the duplicated "((void)0) | |||
| 2374 | "element from llvm.compiler.used")((void)0); | |||
| 2375 | if (U.usedCount(&V) || U.compilerUsedCount(&V)) | |||
| 2376 | ++N; | |||
| 2377 | return V.hasNUsesOrMore(N); | |||
| 2378 | } | |||
| 2379 | ||||
| 2380 | static bool mayHaveOtherReferences(GlobalAlias &GA, const LLVMUsed &U) { | |||
| 2381 | if (!GA.hasLocalLinkage()) | |||
| 2382 | return true; | |||
| 2383 | ||||
| 2384 | return U.usedCount(&GA) || U.compilerUsedCount(&GA); | |||
| 2385 | } | |||
| 2386 | ||||
| 2387 | static bool hasUsesToReplace(GlobalAlias &GA, const LLVMUsed &U, | |||
| 2388 | bool &RenameTarget) { | |||
| 2389 | RenameTarget = false; | |||
| 2390 | bool Ret = false; | |||
| 2391 | if (hasUseOtherThanLLVMUsed(GA, U)) | |||
| 2392 | Ret = true; | |||
| 2393 | ||||
| 2394 | // If the alias is externally visible, we may still be able to simplify it. | |||
| 2395 | if (!mayHaveOtherReferences(GA, U)) | |||
| 2396 | return Ret; | |||
| 2397 | ||||
| 2398 | // If the aliasee has internal linkage, give it the name and linkage | |||
| 2399 | // of the alias, and delete the alias. This turns: | |||
| 2400 | // define internal ... @f(...) | |||
| 2401 | // @a = alias ... @f | |||
| 2402 | // into: | |||
| 2403 | // define ... @a(...) | |||
| 2404 | Constant *Aliasee = GA.getAliasee(); | |||
| 2405 | GlobalValue *Target = cast<GlobalValue>(Aliasee->stripPointerCasts()); | |||
| 2406 | if (!Target->hasLocalLinkage()) | |||
| 2407 | return Ret; | |||
| 2408 | ||||
| 2409 | // Do not perform the transform if multiple aliases potentially target the | |||
| 2410 | // aliasee. This check also ensures that it is safe to replace the section | |||
| 2411 | // and other attributes of the aliasee with those of the alias. | |||
| 2412 | if (hasMoreThanOneUseOtherThanLLVMUsed(*Target, U)) | |||
| 2413 | return Ret; | |||
| 2414 | ||||
| 2415 | RenameTarget = true; | |||
| 2416 | return true; | |||
| 2417 | } | |||
| 2418 | ||||
| 2419 | static bool | |||
| 2420 | OptimizeGlobalAliases(Module &M, | |||
| 2421 | SmallPtrSetImpl<const Comdat *> &NotDiscardableComdats) { | |||
| 2422 | bool Changed = false; | |||
| 2423 | LLVMUsed Used(M); | |||
| 2424 | ||||
| 2425 | for (GlobalValue *GV : Used.used()) | |||
| 2426 | Used.compilerUsedErase(GV); | |||
| 2427 | ||||
| 2428 | for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end(); | |||
| 2429 | I != E;) { | |||
| 2430 | GlobalAlias *J = &*I++; | |||
| 2431 | ||||
| 2432 | // Aliases without names cannot be referenced outside this module. | |||
| 2433 | if (!J->hasName() && !J->isDeclaration() && !J->hasLocalLinkage()) | |||
| 2434 | J->setLinkage(GlobalValue::InternalLinkage); | |||
| 2435 | ||||
| 2436 | if (deleteIfDead(*J, NotDiscardableComdats)) { | |||
| 2437 | Changed = true; | |||
| 2438 | continue; | |||
| 2439 | } | |||
| 2440 | ||||
| 2441 | // If the alias can change at link time, nothing can be done - bail out. | |||
| 2442 | if (J->isInterposable()) | |||
| 2443 | continue; | |||
| 2444 | ||||
| 2445 | Constant *Aliasee = J->getAliasee(); | |||
| 2446 | GlobalValue *Target = dyn_cast<GlobalValue>(Aliasee->stripPointerCasts()); | |||
| 2447 | // We can't trivially replace the alias with the aliasee if the aliasee is | |||
| 2448 | // non-trivial in some way. We also can't replace the alias with the aliasee | |||
| 2449 | // if the aliasee is interposable because aliases point to the local | |||
| 2450 | // definition. | |||
| 2451 | // TODO: Try to handle non-zero GEPs of local aliasees. | |||
| 2452 | if (!Target || Target->isInterposable()) | |||
| 2453 | continue; | |||
| 2454 | Target->removeDeadConstantUsers(); | |||
| 2455 | ||||
| 2456 | // Make all users of the alias use the aliasee instead. | |||
| 2457 | bool RenameTarget; | |||
| 2458 | if (!hasUsesToReplace(*J, Used, RenameTarget)) | |||
| 2459 | continue; | |||
| 2460 | ||||
| 2461 | J->replaceAllUsesWith(ConstantExpr::getBitCast(Aliasee, J->getType())); | |||
| 2462 | ++NumAliasesResolved; | |||
| 2463 | Changed = true; | |||
| 2464 | ||||
| 2465 | if (RenameTarget) { | |||
| 2466 | // Give the aliasee the name, linkage and other attributes of the alias. | |||
| 2467 | Target->takeName(&*J); | |||
| 2468 | Target->setLinkage(J->getLinkage()); | |||
| 2469 | Target->setDSOLocal(J->isDSOLocal()); | |||
| 2470 | Target->setVisibility(J->getVisibility()); | |||
| 2471 | Target->setDLLStorageClass(J->getDLLStorageClass()); | |||
| 2472 | ||||
| 2473 | if (Used.usedErase(&*J)) | |||
| 2474 | Used.usedInsert(Target); | |||
| 2475 | ||||
| 2476 | if (Used.compilerUsedErase(&*J)) | |||
| 2477 | Used.compilerUsedInsert(Target); | |||
| 2478 | } else if (mayHaveOtherReferences(*J, Used)) | |||
| 2479 | continue; | |||
| 2480 | ||||
| 2481 | // Delete the alias. | |||
| 2482 | M.getAliasList().erase(J); | |||
| 2483 | ++NumAliasesRemoved; | |||
| 2484 | Changed = true; | |||
| 2485 | } | |||
| 2486 | ||||
| 2487 | Used.syncVariablesAndSets(); | |||
| 2488 | ||||
| 2489 | return Changed; | |||
| 2490 | } | |||
| 2491 | ||||
| 2492 | static Function * | |||
| 2493 | FindCXAAtExit(Module &M, function_ref<TargetLibraryInfo &(Function &)> GetTLI) { | |||
| 2494 | // Hack to get a default TLI before we have actual Function. | |||
| 2495 | auto FuncIter = M.begin(); | |||
| 2496 | if (FuncIter == M.end()) | |||
| 2497 | return nullptr; | |||
| 2498 | auto *TLI = &GetTLI(*FuncIter); | |||
| 2499 | ||||
| 2500 | LibFunc F = LibFunc_cxa_atexit; | |||
| 2501 | if (!TLI->has(F)) | |||
| 2502 | return nullptr; | |||
| 2503 | ||||
| 2504 | Function *Fn = M.getFunction(TLI->getName(F)); | |||
| 2505 | if (!Fn) | |||
| 2506 | return nullptr; | |||
| 2507 | ||||
| 2508 | // Now get the actual TLI for Fn. | |||
| 2509 | TLI = &GetTLI(*Fn); | |||
| 2510 | ||||
| 2511 | // Make sure that the function has the correct prototype. | |||
| 2512 | if (!TLI->getLibFunc(*Fn, F) || F != LibFunc_cxa_atexit) | |||
| 2513 | return nullptr; | |||
| 2514 | ||||
| 2515 | return Fn; | |||
| 2516 | } | |||
| 2517 | ||||
| 2518 | /// Returns whether the given function is an empty C++ destructor and can | |||
| 2519 | /// therefore be eliminated. | |||
| 2520 | /// Note that we assume that other optimization passes have already simplified | |||
| 2521 | /// the code so we simply check for 'ret'. | |||
| 2522 | static bool cxxDtorIsEmpty(const Function &Fn) { | |||
| 2523 | // FIXME: We could eliminate C++ destructors if they're readonly/readnone and | |||
| 2524 | // nounwind, but that doesn't seem worth doing. | |||
| 2525 | if (Fn.isDeclaration()) | |||
| 2526 | return false; | |||
| 2527 | ||||
| 2528 | for (auto &I : Fn.getEntryBlock()) { | |||
| 2529 | if (isa<DbgInfoIntrinsic>(I)) | |||
| 2530 | continue; | |||
| 2531 | if (isa<ReturnInst>(I)) | |||
| 2532 | return true; | |||
| 2533 | break; | |||
| 2534 | } | |||
| 2535 | return false; | |||
| 2536 | } | |||
| 2537 | ||||
| 2538 | static bool OptimizeEmptyGlobalCXXDtors(Function *CXAAtExitFn) { | |||
| 2539 | /// Itanium C++ ABI p3.3.5: | |||
| 2540 | /// | |||
| 2541 | /// After constructing a global (or local static) object, that will require | |||
| 2542 | /// destruction on exit, a termination function is registered as follows: | |||
| 2543 | /// | |||
| 2544 | /// extern "C" int __cxa_atexit ( void (*f)(void *), void *p, void *d ); | |||
| 2545 | /// | |||
| 2546 | /// This registration, e.g. __cxa_atexit(f,p,d), is intended to cause the | |||
| 2547 | /// call f(p) when DSO d is unloaded, before all such termination calls | |||
| 2548 | /// registered before this one. It returns zero if registration is | |||
| 2549 | /// successful, nonzero on failure. | |||
| 2550 | ||||
| 2551 | // This pass will look for calls to __cxa_atexit where the function is trivial | |||
| 2552 | // and remove them. | |||
| 2553 | bool Changed = false; | |||
| 2554 | ||||
| 2555 | for (auto I = CXAAtExitFn->user_begin(), E = CXAAtExitFn->user_end(); | |||
| 2556 | I != E;) { | |||
| 2557 | // We're only interested in calls. Theoretically, we could handle invoke | |||
| 2558 | // instructions as well, but neither llvm-gcc nor clang generate invokes | |||
| 2559 | // to __cxa_atexit. | |||
| 2560 | CallInst *CI = dyn_cast<CallInst>(*I++); | |||
| 2561 | if (!CI) | |||
| 2562 | continue; | |||
| 2563 | ||||
| 2564 | Function *DtorFn = | |||
| 2565 | dyn_cast<Function>(CI->getArgOperand(0)->stripPointerCasts()); | |||
| 2566 | if (!DtorFn || !cxxDtorIsEmpty(*DtorFn)) | |||
| 2567 | continue; | |||
| 2568 | ||||
| 2569 | // Just remove the call. | |||
| 2570 | CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); | |||
| 2571 | CI->eraseFromParent(); | |||
| 2572 | ||||
| 2573 | ++NumCXXDtorsRemoved; | |||
| 2574 | ||||
| 2575 | Changed |= true; | |||
| 2576 | } | |||
| 2577 | ||||
| 2578 | return Changed; | |||
| 2579 | } | |||
| 2580 | ||||
| 2581 | static bool optimizeGlobalsInModule( | |||
| 2582 | Module &M, const DataLayout &DL, | |||
| 2583 | function_ref<TargetLibraryInfo &(Function &)> GetTLI, | |||
| 2584 | function_ref<TargetTransformInfo &(Function &)> GetTTI, | |||
| 2585 | function_ref<BlockFrequencyInfo &(Function &)> GetBFI, | |||
| 2586 | function_ref<DominatorTree &(Function &)> LookupDomTree) { | |||
| 2587 | SmallPtrSet<const Comdat *, 8> NotDiscardableComdats; | |||
| 2588 | bool Changed = false; | |||
| 2589 | bool LocalChange = true; | |||
| 2590 | while (LocalChange) { | |||
| 2591 | LocalChange = false; | |||
| 2592 | ||||
| 2593 | NotDiscardableComdats.clear(); | |||
| 2594 | for (const GlobalVariable &GV : M.globals()) | |||
| 2595 | if (const Comdat *C = GV.getComdat()) | |||
| 2596 | if (!GV.isDiscardableIfUnused() || !GV.use_empty()) | |||
| 2597 | NotDiscardableComdats.insert(C); | |||
| 2598 | for (Function &F : M) | |||
| 2599 | if (const Comdat *C = F.getComdat()) | |||
| 2600 | if (!F.isDefTriviallyDead()) | |||
| 2601 | NotDiscardableComdats.insert(C); | |||
| 2602 | for (GlobalAlias &GA : M.aliases()) | |||
| 2603 | if (const Comdat *C = GA.getComdat()) | |||
| 2604 | if (!GA.isDiscardableIfUnused() || !GA.use_empty()) | |||
| 2605 | NotDiscardableComdats.insert(C); | |||
| 2606 | ||||
| 2607 | // Delete functions that are trivially dead, ccc -> fastcc | |||
| 2608 | LocalChange |= OptimizeFunctions(M, GetTLI, GetTTI, GetBFI, LookupDomTree, | |||
| 2609 | NotDiscardableComdats); | |||
| 2610 | ||||
| 2611 | // Optimize global_ctors list. | |||
| 2612 | LocalChange |= optimizeGlobalCtorsList(M, [&](Function *F) { | |||
| 2613 | return EvaluateStaticConstructor(F, DL, &GetTLI(*F)); | |||
| ||||
| 2614 | }); | |||
| 2615 | ||||
| 2616 | // Optimize non-address-taken globals. | |||
| 2617 | LocalChange |= | |||
| 2618 | OptimizeGlobalVars(M, GetTLI, LookupDomTree, NotDiscardableComdats); | |||
| 2619 | ||||
| 2620 | // Resolve aliases, when possible. | |||
| 2621 | LocalChange |= OptimizeGlobalAliases(M, NotDiscardableComdats); | |||
| 2622 | ||||
| 2623 | // Try to remove trivial global destructors if they are not removed | |||
| 2624 | // already. | |||
| 2625 | Function *CXAAtExitFn = FindCXAAtExit(M, GetTLI); | |||
| 2626 | if (CXAAtExitFn) | |||
| 2627 | LocalChange |= OptimizeEmptyGlobalCXXDtors(CXAAtExitFn); | |||
| 2628 | ||||
| 2629 | Changed |= LocalChange; | |||
| 2630 | } | |||
| 2631 | ||||
| 2632 | // TODO: Move all global ctors functions to the end of the module for code | |||
| 2633 | // layout. | |||
| 2634 | ||||
| 2635 | return Changed; | |||
| 2636 | } | |||
| 2637 | ||||
| 2638 | PreservedAnalyses GlobalOptPass::run(Module &M, ModuleAnalysisManager &AM) { | |||
| 2639 | auto &DL = M.getDataLayout(); | |||
| 2640 | auto &FAM = | |||
| 2641 | AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); | |||
| 2642 | auto LookupDomTree = [&FAM](Function &F) -> DominatorTree &{ | |||
| 2643 | return FAM.getResult<DominatorTreeAnalysis>(F); | |||
| 2644 | }; | |||
| 2645 | auto GetTLI = [&FAM](Function &F) -> TargetLibraryInfo & { | |||
| 2646 | return FAM.getResult<TargetLibraryAnalysis>(F); | |||
| 2647 | }; | |||
| 2648 | auto GetTTI = [&FAM](Function &F) -> TargetTransformInfo & { | |||
| 2649 | return FAM.getResult<TargetIRAnalysis>(F); | |||
| 2650 | }; | |||
| 2651 | ||||
| 2652 | auto GetBFI = [&FAM](Function &F) -> BlockFrequencyInfo & { | |||
| 2653 | return FAM.getResult<BlockFrequencyAnalysis>(F); | |||
| 2654 | }; | |||
| 2655 | ||||
| 2656 | if (!optimizeGlobalsInModule(M, DL, GetTLI, GetTTI, GetBFI, LookupDomTree)) | |||
| 2657 | return PreservedAnalyses::all(); | |||
| 2658 | return PreservedAnalyses::none(); | |||
| 2659 | } | |||
| 2660 | ||||
| 2661 | namespace { | |||
| 2662 | ||||
| 2663 | struct GlobalOptLegacyPass : public ModulePass { | |||
| 2664 | static char ID; // Pass identification, replacement for typeid | |||
| 2665 | ||||
| 2666 | GlobalOptLegacyPass() : ModulePass(ID) { | |||
| 2667 | initializeGlobalOptLegacyPassPass(*PassRegistry::getPassRegistry()); | |||
| 2668 | } | |||
| 2669 | ||||
| 2670 | bool runOnModule(Module &M) override { | |||
| 2671 | if (skipModule(M)) | |||
| 2672 | return false; | |||
| 2673 | ||||
| 2674 | auto &DL = M.getDataLayout(); | |||
| 2675 | auto LookupDomTree = [this](Function &F) -> DominatorTree & { | |||
| 2676 | return this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); | |||
| 2677 | }; | |||
| 2678 | auto GetTLI = [this](Function &F) -> TargetLibraryInfo & { | |||
| 2679 | return this->getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F); | |||
| 2680 | }; | |||
| 2681 | auto GetTTI = [this](Function &F) -> TargetTransformInfo & { | |||
| 2682 | return this->getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F); | |||
| 2683 | }; | |||
| 2684 | ||||
| 2685 | auto GetBFI = [this](Function &F) -> BlockFrequencyInfo & { | |||
| 2686 | return this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI(); | |||
| 2687 | }; | |||
| 2688 | ||||
| 2689 | return optimizeGlobalsInModule(M, DL, GetTLI, GetTTI, GetBFI, | |||
| 2690 | LookupDomTree); | |||
| 2691 | } | |||
| 2692 | ||||
| 2693 | void getAnalysisUsage(AnalysisUsage &AU) const override { | |||
| 2694 | AU.addRequired<TargetLibraryInfoWrapperPass>(); | |||
| 2695 | AU.addRequired<TargetTransformInfoWrapperPass>(); | |||
| 2696 | AU.addRequired<DominatorTreeWrapperPass>(); | |||
| 2697 | AU.addRequired<BlockFrequencyInfoWrapperPass>(); | |||
| 2698 | } | |||
| 2699 | }; | |||
| 2700 | ||||
| 2701 | } // end anonymous namespace | |||
| 2702 | ||||
| 2703 | char GlobalOptLegacyPass::ID = 0; | |||
| 2704 | ||||
| 2705 | INITIALIZE_PASS_BEGIN(GlobalOptLegacyPass, "globalopt",static void *initializeGlobalOptLegacyPassPassOnce(PassRegistry &Registry) { | |||
| 2706 | "Global Variable Optimizer", false, false)static void *initializeGlobalOptLegacyPassPassOnce(PassRegistry &Registry) { | |||
| 2707 | INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry); | |||
| 2708 | INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry); | |||
| 2709 | INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)initializeBlockFrequencyInfoWrapperPassPass(Registry); | |||
| 2710 | INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry); | |||
| 2711 | INITIALIZE_PASS_END(GlobalOptLegacyPass, "globalopt",PassInfo *PI = new PassInfo( "Global Variable Optimizer", "globalopt" , &GlobalOptLegacyPass::ID, PassInfo::NormalCtor_t(callDefaultCtor <GlobalOptLegacyPass>), false, false); Registry.registerPass (*PI, true); return PI; } static llvm::once_flag InitializeGlobalOptLegacyPassPassFlag ; void llvm::initializeGlobalOptLegacyPassPass(PassRegistry & Registry) { llvm::call_once(InitializeGlobalOptLegacyPassPassFlag , initializeGlobalOptLegacyPassPassOnce, std::ref(Registry)); } | |||
| 2712 | "Global Variable Optimizer", false, false)PassInfo *PI = new PassInfo( "Global Variable Optimizer", "globalopt" , &GlobalOptLegacyPass::ID, PassInfo::NormalCtor_t(callDefaultCtor <GlobalOptLegacyPass>), false, false); Registry.registerPass (*PI, true); return PI; } static llvm::once_flag InitializeGlobalOptLegacyPassPassFlag ; void llvm::initializeGlobalOptLegacyPassPass(PassRegistry & Registry) { llvm::call_once(InitializeGlobalOptLegacyPassPassFlag , initializeGlobalOptLegacyPassPassOnce, std::ref(Registry)); } | |||
| 2713 | ||||
| 2714 | ModulePass *llvm::createGlobalOptimizerPass() { | |||
| 2715 | return new GlobalOptLegacyPass(); | |||
| 2716 | } |
| 1 | //===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // |
| 9 | // This file defines the SmallVector class. |
| 10 | // |
| 11 | //===----------------------------------------------------------------------===// |
| 12 | |
| 13 | #ifndef LLVM_ADT_SMALLVECTOR_H |
| 14 | #define LLVM_ADT_SMALLVECTOR_H |
| 15 | |
| 16 | #include "llvm/ADT/iterator_range.h" |
| 17 | #include "llvm/Support/Compiler.h" |
| 18 | #include "llvm/Support/ErrorHandling.h" |
| 19 | #include "llvm/Support/MemAlloc.h" |
| 20 | #include "llvm/Support/type_traits.h" |
| 21 | #include <algorithm> |
| 22 | #include <cassert> |
| 23 | #include <cstddef> |
| 24 | #include <cstdlib> |
| 25 | #include <cstring> |
| 26 | #include <functional> |
| 27 | #include <initializer_list> |
| 28 | #include <iterator> |
| 29 | #include <limits> |
| 30 | #include <memory> |
| 31 | #include <new> |
| 32 | #include <type_traits> |
| 33 | #include <utility> |
| 34 | |
| 35 | namespace llvm { |
| 36 | |
| 37 | /// This is all the stuff common to all SmallVectors. |
| 38 | /// |
| 39 | /// The template parameter specifies the type which should be used to hold the |
| 40 | /// Size and Capacity of the SmallVector, so it can be adjusted. |
| 41 | /// Using 32 bit size is desirable to shrink the size of the SmallVector. |
| 42 | /// Using 64 bit size is desirable for cases like SmallVector<char>, where a |
| 43 | /// 32 bit size would limit the vector to ~4GB. SmallVectors are used for |
| 44 | /// buffering bitcode output - which can exceed 4GB. |
| 45 | template <class Size_T> class SmallVectorBase { |
| 46 | protected: |
| 47 | void *BeginX; |
| 48 | Size_T Size = 0, Capacity; |
| 49 | |
| 50 | /// The maximum value of the Size_T used. |
| 51 | static constexpr size_t SizeTypeMax() { |
| 52 | return std::numeric_limits<Size_T>::max(); |
| 53 | } |
| 54 | |
| 55 | SmallVectorBase() = delete; |
| 56 | SmallVectorBase(void *FirstEl, size_t TotalCapacity) |
| 57 | : BeginX(FirstEl), Capacity(TotalCapacity) {} |
| 58 | |
| 59 | /// This is a helper for \a grow() that's out of line to reduce code |
| 60 | /// duplication. This function will report a fatal error if it can't grow at |
| 61 | /// least to \p MinSize. |
| 62 | void *mallocForGrow(size_t MinSize, size_t TSize, size_t &NewCapacity); |
| 63 | |
| 64 | /// This is an implementation of the grow() method which only works |
| 65 | /// on POD-like data types and is out of line to reduce code duplication. |
| 66 | /// This function will report a fatal error if it cannot increase capacity. |
| 67 | void grow_pod(void *FirstEl, size_t MinSize, size_t TSize); |
| 68 | |
| 69 | public: |
| 70 | size_t size() const { return Size; } |
| 71 | size_t capacity() const { return Capacity; } |
| 72 | |
| 73 | LLVM_NODISCARD[[clang::warn_unused_result]] bool empty() const { return !Size; } |
| 74 | |
| 75 | /// Set the array size to \p N, which the current array must have enough |
| 76 | /// capacity for. |
| 77 | /// |
| 78 | /// This does not construct or destroy any elements in the vector. |
| 79 | /// |
| 80 | /// Clients can use this in conjunction with capacity() to write past the end |
| 81 | /// of the buffer when they know that more elements are available, and only |
| 82 | /// update the size later. This avoids the cost of value initializing elements |
| 83 | /// which will only be overwritten. |
| 84 | void set_size(size_t N) { |
| 85 | assert(N <= capacity())((void)0); |
| 86 | Size = N; |
| 87 | } |
| 88 | }; |
| 89 | |
| 90 | template <class T> |
| 91 | using SmallVectorSizeType = |
| 92 | typename std::conditional<sizeof(T) < 4 && sizeof(void *) >= 8, uint64_t, |
| 93 | uint32_t>::type; |
| 94 | |
| 95 | /// Figure out the offset of the first element. |
| 96 | template <class T, typename = void> struct SmallVectorAlignmentAndSize { |
| 97 | alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof( |
| 98 | SmallVectorBase<SmallVectorSizeType<T>>)]; |
| 99 | alignas(T) char FirstEl[sizeof(T)]; |
| 100 | }; |
| 101 | |
| 102 | /// This is the part of SmallVectorTemplateBase which does not depend on whether |
| 103 | /// the type T is a POD. The extra dummy template argument is used by ArrayRef |
| 104 | /// to avoid unnecessarily requiring T to be complete. |
| 105 | template <typename T, typename = void> |
| 106 | class SmallVectorTemplateCommon |
| 107 | : public SmallVectorBase<SmallVectorSizeType<T>> { |
| 108 | using Base = SmallVectorBase<SmallVectorSizeType<T>>; |
| 109 | |
| 110 | /// Find the address of the first element. For this pointer math to be valid |
| 111 | /// with small-size of 0 for T with lots of alignment, it's important that |
| 112 | /// SmallVectorStorage is properly-aligned even for small-size of 0. |
| 113 | void *getFirstEl() const { |
| 114 | return const_cast<void *>(reinterpret_cast<const void *>( |
| 115 | reinterpret_cast<const char *>(this) + |
| 116 | offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)__builtin_offsetof(SmallVectorAlignmentAndSize<T>, FirstEl ))); |
| 117 | } |
| 118 | // Space after 'FirstEl' is clobbered, do not add any instance vars after it. |
| 119 | |
| 120 | protected: |
| 121 | SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {} |
| 122 | |
| 123 | void grow_pod(size_t MinSize, size_t TSize) { |
| 124 | Base::grow_pod(getFirstEl(), MinSize, TSize); |
| 125 | } |
| 126 | |
| 127 | /// Return true if this is a smallvector which has not had dynamic |
| 128 | /// memory allocated for it. |
| 129 | bool isSmall() const { return this->BeginX == getFirstEl(); } |
| 130 | |
| 131 | /// Put this vector in a state of being small. |
| 132 | void resetToSmall() { |
| 133 | this->BeginX = getFirstEl(); |
| 134 | this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect. |
| 135 | } |
| 136 | |
| 137 | /// Return true if V is an internal reference to the given range. |
| 138 | bool isReferenceToRange(const void *V, const void *First, const void *Last) const { |
| 139 | // Use std::less to avoid UB. |
| 140 | std::less<> LessThan; |
| 141 | return !LessThan(V, First) && LessThan(V, Last); |
| 142 | } |
| 143 | |
| 144 | /// Return true if V is an internal reference to this vector. |
| 145 | bool isReferenceToStorage(const void *V) const { |
| 146 | return isReferenceToRange(V, this->begin(), this->end()); |
| 147 | } |
| 148 | |
| 149 | /// Return true if First and Last form a valid (possibly empty) range in this |
| 150 | /// vector's storage. |
| 151 | bool isRangeInStorage(const void *First, const void *Last) const { |
| 152 | // Use std::less to avoid UB. |
| 153 | std::less<> LessThan; |
| 154 | return !LessThan(First, this->begin()) && !LessThan(Last, First) && |
| 155 | !LessThan(this->end(), Last); |
| 156 | } |
| 157 | |
| 158 | /// Return true unless Elt will be invalidated by resizing the vector to |
| 159 | /// NewSize. |
| 160 | bool isSafeToReferenceAfterResize(const void *Elt, size_t NewSize) { |
| 161 | // Past the end. |
| 162 | if (LLVM_LIKELY(!isReferenceToStorage(Elt))__builtin_expect((bool)(!isReferenceToStorage(Elt)), true)) |
| 163 | return true; |
| 164 | |
| 165 | // Return false if Elt will be destroyed by shrinking. |
| 166 | if (NewSize <= this->size()) |
| 167 | return Elt < this->begin() + NewSize; |
| 168 | |
| 169 | // Return false if we need to grow. |
| 170 | return NewSize <= this->capacity(); |
| 171 | } |
| 172 | |
| 173 | /// Check whether Elt will be invalidated by resizing the vector to NewSize. |
| 174 | void assertSafeToReferenceAfterResize(const void *Elt, size_t NewSize) { |
| 175 | assert(isSafeToReferenceAfterResize(Elt, NewSize) &&((void)0) |
| 176 | "Attempting to reference an element of the vector in an operation "((void)0) |
| 177 | "that invalidates it")((void)0); |
| 178 | } |
| 179 | |
| 180 | /// Check whether Elt will be invalidated by increasing the size of the |
| 181 | /// vector by N. |
| 182 | void assertSafeToAdd(const void *Elt, size_t N = 1) { |
| 183 | this->assertSafeToReferenceAfterResize(Elt, this->size() + N); |
| 184 | } |
| 185 | |
| 186 | /// Check whether any part of the range will be invalidated by clearing. |
| 187 | void assertSafeToReferenceAfterClear(const T *From, const T *To) { |
| 188 | if (From == To) |
| 189 | return; |
| 190 | this->assertSafeToReferenceAfterResize(From, 0); |
| 191 | this->assertSafeToReferenceAfterResize(To - 1, 0); |
| 192 | } |
| 193 | template < |
| 194 | class ItTy, |
| 195 | std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value, |
| 196 | bool> = false> |
| 197 | void assertSafeToReferenceAfterClear(ItTy, ItTy) {} |
| 198 | |
| 199 | /// Check whether any part of the range will be invalidated by growing. |
| 200 | void assertSafeToAddRange(const T *From, const T *To) { |
| 201 | if (From == To) |
| 202 | return; |
| 203 | this->assertSafeToAdd(From, To - From); |
| 204 | this->assertSafeToAdd(To - 1, To - From); |
| 205 | } |
| 206 | template < |
| 207 | class ItTy, |
| 208 | std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value, |
| 209 | bool> = false> |
| 210 | void assertSafeToAddRange(ItTy, ItTy) {} |
| 211 | |
| 212 | /// Reserve enough space to add one element, and return the updated element |
| 213 | /// pointer in case it was a reference to the storage. |
| 214 | template <class U> |
| 215 | static const T *reserveForParamAndGetAddressImpl(U *This, const T &Elt, |
| 216 | size_t N) { |
| 217 | size_t NewSize = This->size() + N; |
| 218 | if (LLVM_LIKELY(NewSize <= This->capacity())__builtin_expect((bool)(NewSize <= This->capacity()), true )) |
| 219 | return &Elt; |
| 220 | |
| 221 | bool ReferencesStorage = false; |
| 222 | int64_t Index = -1; |
| 223 | if (!U::TakesParamByValue) { |
| 224 | if (LLVM_UNLIKELY(This->isReferenceToStorage(&Elt))__builtin_expect((bool)(This->isReferenceToStorage(&Elt )), false)) { |
| 225 | ReferencesStorage = true; |
| 226 | Index = &Elt - This->begin(); |
| 227 | } |
| 228 | } |
| 229 | This->grow(NewSize); |
| 230 | return ReferencesStorage ? This->begin() + Index : &Elt; |
| 231 | } |
| 232 | |
| 233 | public: |
| 234 | using size_type = size_t; |
| 235 | using difference_type = ptrdiff_t; |
| 236 | using value_type = T; |
| 237 | using iterator = T *; |
| 238 | using const_iterator = const T *; |
| 239 | |
| 240 | using const_reverse_iterator = std::reverse_iterator<const_iterator>; |
| 241 | using reverse_iterator = std::reverse_iterator<iterator>; |
| 242 | |
| 243 | using reference = T &; |
| 244 | using const_reference = const T &; |
| 245 | using pointer = T *; |
| 246 | using const_pointer = const T *; |
| 247 | |
| 248 | using Base::capacity; |
| 249 | using Base::empty; |
| 250 | using Base::size; |
| 251 | |
| 252 | // forward iterator creation methods. |
| 253 | iterator begin() { return (iterator)this->BeginX; } |
| 254 | const_iterator begin() const { return (const_iterator)this->BeginX; } |
| 255 | iterator end() { return begin() + size(); } |
| 256 | const_iterator end() const { return begin() + size(); } |
| 257 | |
| 258 | // reverse iterator creation methods. |
| 259 | reverse_iterator rbegin() { return reverse_iterator(end()); } |
| 260 | const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); } |
| 261 | reverse_iterator rend() { return reverse_iterator(begin()); } |
| 262 | const_reverse_iterator rend() const { return const_reverse_iterator(begin());} |
| 263 | |
| 264 | size_type size_in_bytes() const { return size() * sizeof(T); } |
| 265 | size_type max_size() const { |
| 266 | return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T)); |
| 267 | } |
| 268 | |
| 269 | size_t capacity_in_bytes() const { return capacity() * sizeof(T); } |
| 270 | |
| 271 | /// Return a pointer to the vector's buffer, even if empty(). |
| 272 | pointer data() { return pointer(begin()); } |
| 273 | /// Return a pointer to the vector's buffer, even if empty(). |
| 274 | const_pointer data() const { return const_pointer(begin()); } |
| 275 | |
| 276 | reference operator[](size_type idx) { |
| 277 | assert(idx < size())((void)0); |
| 278 | return begin()[idx]; |
| 279 | } |
| 280 | const_reference operator[](size_type idx) const { |
| 281 | assert(idx < size())((void)0); |
| 282 | return begin()[idx]; |
| 283 | } |
| 284 | |
| 285 | reference front() { |
| 286 | assert(!empty())((void)0); |
| 287 | return begin()[0]; |
| 288 | } |
| 289 | const_reference front() const { |
| 290 | assert(!empty())((void)0); |
| 291 | return begin()[0]; |
| 292 | } |
| 293 | |
| 294 | reference back() { |
| 295 | assert(!empty())((void)0); |
| 296 | return end()[-1]; |
| 297 | } |
| 298 | const_reference back() const { |
| 299 | assert(!empty())((void)0); |
| 300 | return end()[-1]; |
| 301 | } |
| 302 | }; |
| 303 | |
| 304 | /// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put |
| 305 | /// method implementations that are designed to work with non-trivial T's. |
| 306 | /// |
| 307 | /// We approximate is_trivially_copyable with trivial move/copy construction and |
| 308 | /// trivial destruction. While the standard doesn't specify that you're allowed |
| 309 | /// copy these types with memcpy, there is no way for the type to observe this. |
| 310 | /// This catches the important case of std::pair<POD, POD>, which is not |
| 311 | /// trivially assignable. |
| 312 | template <typename T, bool = (is_trivially_copy_constructible<T>::value) && |
| 313 | (is_trivially_move_constructible<T>::value) && |
| 314 | std::is_trivially_destructible<T>::value> |
| 315 | class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> { |
| 316 | friend class SmallVectorTemplateCommon<T>; |
| 317 | |
| 318 | protected: |
| 319 | static constexpr bool TakesParamByValue = false; |
| 320 | using ValueParamT = const T &; |
| 321 | |
| 322 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} |
| 323 | |
| 324 | static void destroy_range(T *S, T *E) { |
| 325 | while (S != E) { |
| 326 | --E; |
| 327 | E->~T(); |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | /// Move the range [I, E) into the uninitialized memory starting with "Dest", |
| 332 | /// constructing elements as needed. |
| 333 | template<typename It1, typename It2> |
| 334 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { |
| 335 | std::uninitialized_copy(std::make_move_iterator(I), |
| 336 | std::make_move_iterator(E), Dest); |
| 337 | } |
| 338 | |
| 339 | /// Copy the range [I, E) onto the uninitialized memory starting with "Dest", |
| 340 | /// constructing elements as needed. |
| 341 | template<typename It1, typename It2> |
| 342 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { |
| 343 | std::uninitialized_copy(I, E, Dest); |
| 344 | } |
| 345 | |
| 346 | /// Grow the allocated memory (without initializing new elements), doubling |
| 347 | /// the size of the allocated memory. Guarantees space for at least one more |
| 348 | /// element, or MinSize more elements if specified. |
| 349 | void grow(size_t MinSize = 0); |
| 350 | |
| 351 | /// Create a new allocation big enough for \p MinSize and pass back its size |
| 352 | /// in \p NewCapacity. This is the first section of \a grow(). |
| 353 | T *mallocForGrow(size_t MinSize, size_t &NewCapacity) { |
| 354 | return static_cast<T *>( |
| 355 | SmallVectorBase<SmallVectorSizeType<T>>::mallocForGrow( |
| 356 | MinSize, sizeof(T), NewCapacity)); |
| 357 | } |
| 358 | |
| 359 | /// Move existing elements over to the new allocation \p NewElts, the middle |
| 360 | /// section of \a grow(). |
| 361 | void moveElementsForGrow(T *NewElts); |
| 362 | |
| 363 | /// Transfer ownership of the allocation, finishing up \a grow(). |
| 364 | void takeAllocationForGrow(T *NewElts, size_t NewCapacity); |
| 365 | |
| 366 | /// Reserve enough space to add one element, and return the updated element |
| 367 | /// pointer in case it was a reference to the storage. |
| 368 | const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) { |
| 369 | return this->reserveForParamAndGetAddressImpl(this, Elt, N); |
| 370 | } |
| 371 | |
| 372 | /// Reserve enough space to add one element, and return the updated element |
| 373 | /// pointer in case it was a reference to the storage. |
| 374 | T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) { |
| 375 | return const_cast<T *>( |
| 376 | this->reserveForParamAndGetAddressImpl(this, Elt, N)); |
| 377 | } |
| 378 | |
| 379 | static T &&forward_value_param(T &&V) { return std::move(V); } |
| 380 | static const T &forward_value_param(const T &V) { return V; } |
| 381 | |
| 382 | void growAndAssign(size_t NumElts, const T &Elt) { |
| 383 | // Grow manually in case Elt is an internal reference. |
| 384 | size_t NewCapacity; |
| 385 | T *NewElts = mallocForGrow(NumElts, NewCapacity); |
| 386 | std::uninitialized_fill_n(NewElts, NumElts, Elt); |
| 387 | this->destroy_range(this->begin(), this->end()); |
| 388 | takeAllocationForGrow(NewElts, NewCapacity); |
| 389 | this->set_size(NumElts); |
| 390 | } |
| 391 | |
| 392 | template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) { |
| 393 | // Grow manually in case one of Args is an internal reference. |
| 394 | size_t NewCapacity; |
| 395 | T *NewElts = mallocForGrow(0, NewCapacity); |
| 396 | ::new ((void *)(NewElts + this->size())) T(std::forward<ArgTypes>(Args)...); |
| 397 | moveElementsForGrow(NewElts); |
| 398 | takeAllocationForGrow(NewElts, NewCapacity); |
| 399 | this->set_size(this->size() + 1); |
| 400 | return this->back(); |
| 401 | } |
| 402 | |
| 403 | public: |
| 404 | void push_back(const T &Elt) { |
| 405 | const T *EltPtr = reserveForParamAndGetAddress(Elt); |
| 406 | ::new ((void *)this->end()) T(*EltPtr); |
| 407 | this->set_size(this->size() + 1); |
| 408 | } |
| 409 | |
| 410 | void push_back(T &&Elt) { |
| 411 | T *EltPtr = reserveForParamAndGetAddress(Elt); |
| 412 | ::new ((void *)this->end()) T(::std::move(*EltPtr)); |
| 413 | this->set_size(this->size() + 1); |
| 414 | } |
| 415 | |
| 416 | void pop_back() { |
| 417 | this->set_size(this->size() - 1); |
| 418 | this->end()->~T(); |
| 419 | } |
| 420 | }; |
| 421 | |
| 422 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
| 423 | template <typename T, bool TriviallyCopyable> |
| 424 | void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) { |
| 425 | size_t NewCapacity; |
| 426 | T *NewElts = mallocForGrow(MinSize, NewCapacity); |
| 427 | moveElementsForGrow(NewElts); |
| 428 | takeAllocationForGrow(NewElts, NewCapacity); |
| 429 | } |
| 430 | |
| 431 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
| 432 | template <typename T, bool TriviallyCopyable> |
| 433 | void SmallVectorTemplateBase<T, TriviallyCopyable>::moveElementsForGrow( |
| 434 | T *NewElts) { |
| 435 | // Move the elements over. |
| 436 | this->uninitialized_move(this->begin(), this->end(), NewElts); |
| 437 | |
| 438 | // Destroy the original elements. |
| 439 | destroy_range(this->begin(), this->end()); |
| 440 | } |
| 441 | |
| 442 | // Define this out-of-line to dissuade the C++ compiler from inlining it. |
| 443 | template <typename T, bool TriviallyCopyable> |
| 444 | void SmallVectorTemplateBase<T, TriviallyCopyable>::takeAllocationForGrow( |
| 445 | T *NewElts, size_t NewCapacity) { |
| 446 | // If this wasn't grown from the inline copy, deallocate the old space. |
| 447 | if (!this->isSmall()) |
| 448 | free(this->begin()); |
| 449 | |
| 450 | this->BeginX = NewElts; |
| 451 | this->Capacity = NewCapacity; |
| 452 | } |
| 453 | |
| 454 | /// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put |
| 455 | /// method implementations that are designed to work with trivially copyable |
| 456 | /// T's. This allows using memcpy in place of copy/move construction and |
| 457 | /// skipping destruction. |
| 458 | template <typename T> |
| 459 | class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> { |
| 460 | friend class SmallVectorTemplateCommon<T>; |
| 461 | |
| 462 | protected: |
| 463 | /// True if it's cheap enough to take parameters by value. Doing so avoids |
| 464 | /// overhead related to mitigations for reference invalidation. |
| 465 | static constexpr bool TakesParamByValue = sizeof(T) <= 2 * sizeof(void *); |
| 466 | |
| 467 | /// Either const T& or T, depending on whether it's cheap enough to take |
| 468 | /// parameters by value. |
| 469 | using ValueParamT = |
| 470 | typename std::conditional<TakesParamByValue, T, const T &>::type; |
| 471 | |
| 472 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} |
| 473 | |
| 474 | // No need to do a destroy loop for POD's. |
| 475 | static void destroy_range(T *, T *) {} |
| 476 | |
| 477 | /// Move the range [I, E) onto the uninitialized memory |
| 478 | /// starting with "Dest", constructing elements into it as needed. |
| 479 | template<typename It1, typename It2> |
| 480 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { |
| 481 | // Just do a copy. |
| 482 | uninitialized_copy(I, E, Dest); |
| 483 | } |
| 484 | |
| 485 | /// Copy the range [I, E) onto the uninitialized memory |
| 486 | /// starting with "Dest", constructing elements into it as needed. |
| 487 | template<typename It1, typename It2> |
| 488 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { |
| 489 | // Arbitrary iterator types; just use the basic implementation. |
| 490 | std::uninitialized_copy(I, E, Dest); |
| 491 | } |
| 492 | |
| 493 | /// Copy the range [I, E) onto the uninitialized memory |
| 494 | /// starting with "Dest", constructing elements into it as needed. |
| 495 | template <typename T1, typename T2> |
| 496 | static void uninitialized_copy( |
| 497 | T1 *I, T1 *E, T2 *Dest, |
| 498 | std::enable_if_t<std::is_same<typename std::remove_const<T1>::type, |
| 499 | T2>::value> * = nullptr) { |
| 500 | // Use memcpy for PODs iterated by pointers (which includes SmallVector |
| 501 | // iterators): std::uninitialized_copy optimizes to memmove, but we can |
| 502 | // use memcpy here. Note that I and E are iterators and thus might be |
| 503 | // invalid for memcpy if they are equal. |
| 504 | if (I != E) |
| 505 | memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T)); |
| 506 | } |
| 507 | |
| 508 | /// Double the size of the allocated memory, guaranteeing space for at |
| 509 | /// least one more element or MinSize if specified. |
| 510 | void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); } |
| 511 | |
| 512 | /// Reserve enough space to add one element, and return the updated element |
| 513 | /// pointer in case it was a reference to the storage. |
| 514 | const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) { |
| 515 | return this->reserveForParamAndGetAddressImpl(this, Elt, N); |
| 516 | } |
| 517 | |
| 518 | /// Reserve enough space to add one element, and return the updated element |
| 519 | /// pointer in case it was a reference to the storage. |
| 520 | T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) { |
| 521 | return const_cast<T *>( |
| 522 | this->reserveForParamAndGetAddressImpl(this, Elt, N)); |
| 523 | } |
| 524 | |
| 525 | /// Copy \p V or return a reference, depending on \a ValueParamT. |
| 526 | static ValueParamT forward_value_param(ValueParamT V) { return V; } |
| 527 | |
| 528 | void growAndAssign(size_t NumElts, T Elt) { |
| 529 | // Elt has been copied in case it's an internal reference, side-stepping |
| 530 | // reference invalidation problems without losing the realloc optimization. |
| 531 | this->set_size(0); |
| 532 | this->grow(NumElts); |
| 533 | std::uninitialized_fill_n(this->begin(), NumElts, Elt); |
| 534 | this->set_size(NumElts); |
| 535 | } |
| 536 | |
| 537 | template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) { |
| 538 | // Use push_back with a copy in case Args has an internal reference, |
| 539 | // side-stepping reference invalidation problems without losing the realloc |
| 540 | // optimization. |
| 541 | push_back(T(std::forward<ArgTypes>(Args)...)); |
| 542 | return this->back(); |
| 543 | } |
| 544 | |
| 545 | public: |
| 546 | void push_back(ValueParamT Elt) { |
| 547 | const T *EltPtr = reserveForParamAndGetAddress(Elt); |
| 548 | memcpy(reinterpret_cast<void *>(this->end()), EltPtr, sizeof(T)); |
| 549 | this->set_size(this->size() + 1); |
| 550 | } |
| 551 | |
| 552 | void pop_back() { this->set_size(this->size() - 1); } |
| 553 | }; |
| 554 | |
| 555 | /// This class consists of common code factored out of the SmallVector class to |
| 556 | /// reduce code duplication based on the SmallVector 'N' template parameter. |
| 557 | template <typename T> |
| 558 | class SmallVectorImpl : public SmallVectorTemplateBase<T> { |
| 559 | using SuperClass = SmallVectorTemplateBase<T>; |
| 560 | |
| 561 | public: |
| 562 | using iterator = typename SuperClass::iterator; |
| 563 | using const_iterator = typename SuperClass::const_iterator; |
| 564 | using reference = typename SuperClass::reference; |
| 565 | using size_type = typename SuperClass::size_type; |
| 566 | |
| 567 | protected: |
| 568 | using SmallVectorTemplateBase<T>::TakesParamByValue; |
| 569 | using ValueParamT = typename SuperClass::ValueParamT; |
| 570 | |
| 571 | // Default ctor - Initialize to empty. |
| 572 | explicit SmallVectorImpl(unsigned N) |
| 573 | : SmallVectorTemplateBase<T>(N) {} |
| 574 | |
| 575 | public: |
| 576 | SmallVectorImpl(const SmallVectorImpl &) = delete; |
| 577 | |
| 578 | ~SmallVectorImpl() { |
| 579 | // Subclass has already destructed this vector's elements. |
| 580 | // If this wasn't grown from the inline copy, deallocate the old space. |
| 581 | if (!this->isSmall()) |
| 582 | free(this->begin()); |
| 583 | } |
| 584 | |
| 585 | void clear() { |
| 586 | this->destroy_range(this->begin(), this->end()); |
| 587 | this->Size = 0; |
| 588 | } |
| 589 | |
| 590 | private: |
| 591 | template <bool ForOverwrite> void resizeImpl(size_type N) { |
| 592 | if (N < this->size()) { |
| 593 | this->pop_back_n(this->size() - N); |
| 594 | } else if (N > this->size()) { |
| 595 | this->reserve(N); |
| 596 | for (auto I = this->end(), E = this->begin() + N; I != E; ++I) |
| 597 | if (ForOverwrite) |
| 598 | new (&*I) T; |
| 599 | else |
| 600 | new (&*I) T(); |
| 601 | this->set_size(N); |
| 602 | } |
| 603 | } |
| 604 | |
| 605 | public: |
| 606 | void resize(size_type N) { resizeImpl<false>(N); } |
| 607 | |
| 608 | /// Like resize, but \ref T is POD, the new values won't be initialized. |
| 609 | void resize_for_overwrite(size_type N) { resizeImpl<true>(N); } |
| 610 | |
| 611 | void resize(size_type N, ValueParamT NV) { |
| 612 | if (N == this->size()) |
| 613 | return; |
| 614 | |
| 615 | if (N < this->size()) { |
| 616 | this->pop_back_n(this->size() - N); |
| 617 | return; |
| 618 | } |
| 619 | |
| 620 | // N > this->size(). Defer to append. |
| 621 | this->append(N - this->size(), NV); |
| 622 | } |
| 623 | |
| 624 | void reserve(size_type N) { |
| 625 | if (this->capacity() < N) |
| 626 | this->grow(N); |
| 627 | } |
| 628 | |
| 629 | void pop_back_n(size_type NumItems) { |
| 630 | assert(this->size() >= NumItems)((void)0); |
| 631 | this->destroy_range(this->end() - NumItems, this->end()); |
| 632 | this->set_size(this->size() - NumItems); |
| 633 | } |
| 634 | |
| 635 | LLVM_NODISCARD[[clang::warn_unused_result]] T pop_back_val() { |
| 636 | T Result = ::std::move(this->back()); |
| 637 | this->pop_back(); |
| 638 | return Result; |
| 639 | } |
| 640 | |
| 641 | void swap(SmallVectorImpl &RHS); |
| 642 | |
| 643 | /// Add the specified range to the end of the SmallVector. |
| 644 | template <typename in_iter, |
| 645 | typename = std::enable_if_t<std::is_convertible< |
| 646 | typename std::iterator_traits<in_iter>::iterator_category, |
| 647 | std::input_iterator_tag>::value>> |
| 648 | void append(in_iter in_start, in_iter in_end) { |
| 649 | this->assertSafeToAddRange(in_start, in_end); |
| 650 | size_type NumInputs = std::distance(in_start, in_end); |
| 651 | this->reserve(this->size() + NumInputs); |
| 652 | this->uninitialized_copy(in_start, in_end, this->end()); |
| 653 | this->set_size(this->size() + NumInputs); |
| 654 | } |
| 655 | |
| 656 | /// Append \p NumInputs copies of \p Elt to the end. |
| 657 | void append(size_type NumInputs, ValueParamT Elt) { |
| 658 | const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumInputs); |
| 659 | std::uninitialized_fill_n(this->end(), NumInputs, *EltPtr); |
| 660 | this->set_size(this->size() + NumInputs); |
| 661 | } |
| 662 | |
| 663 | void append(std::initializer_list<T> IL) { |
| 664 | append(IL.begin(), IL.end()); |
| 665 | } |
| 666 | |
| 667 | void append(const SmallVectorImpl &RHS) { append(RHS.begin(), RHS.end()); } |
| 668 | |
| 669 | void assign(size_type NumElts, ValueParamT Elt) { |
| 670 | // Note that Elt could be an internal reference. |
| 671 | if (NumElts > this->capacity()) { |
| 672 | this->growAndAssign(NumElts, Elt); |
| 673 | return; |
| 674 | } |
| 675 | |
| 676 | // Assign over existing elements. |
| 677 | std::fill_n(this->begin(), std::min(NumElts, this->size()), Elt); |
| 678 | if (NumElts > this->size()) |
| 679 | std::uninitialized_fill_n(this->end(), NumElts - this->size(), Elt); |
| 680 | else if (NumElts < this->size()) |
| 681 | this->destroy_range(this->begin() + NumElts, this->end()); |
| 682 | this->set_size(NumElts); |
| 683 | } |
| 684 | |
| 685 | // FIXME: Consider assigning over existing elements, rather than clearing & |
| 686 | // re-initializing them - for all assign(...) variants. |
| 687 | |
| 688 | template <typename in_iter, |
| 689 | typename = std::enable_if_t<std::is_convertible< |
| 690 | typename std::iterator_traits<in_iter>::iterator_category, |
| 691 | std::input_iterator_tag>::value>> |
| 692 | void assign(in_iter in_start, in_iter in_end) { |
| 693 | this->assertSafeToReferenceAfterClear(in_start, in_end); |
| 694 | clear(); |
| 695 | append(in_start, in_end); |
| 696 | } |
| 697 | |
| 698 | void assign(std::initializer_list<T> IL) { |
| 699 | clear(); |
| 700 | append(IL); |
| 701 | } |
| 702 | |
| 703 | void assign(const SmallVectorImpl &RHS) { assign(RHS.begin(), RHS.end()); } |
| 704 | |
| 705 | iterator erase(const_iterator CI) { |
| 706 | // Just cast away constness because this is a non-const member function. |
| 707 | iterator I = const_cast<iterator>(CI); |
| 708 | |
| 709 | assert(this->isReferenceToStorage(CI) && "Iterator to erase is out of bounds.")((void)0); |
| 710 | |
| 711 | iterator N = I; |
| 712 | // Shift all elts down one. |
| 713 | std::move(I+1, this->end(), I); |
| 714 | // Drop the last elt. |
| 715 | this->pop_back(); |
| 716 | return(N); |
| 717 | } |
| 718 | |
| 719 | iterator erase(const_iterator CS, const_iterator CE) { |
| 720 | // Just cast away constness because this is a non-const member function. |
| 721 | iterator S = const_cast<iterator>(CS); |
| 722 | iterator E = const_cast<iterator>(CE); |
| 723 | |
| 724 | assert(this->isRangeInStorage(S, E) && "Range to erase is out of bounds.")((void)0); |
| 725 | |
| 726 | iterator N = S; |
| 727 | // Shift all elts down. |
| 728 | iterator I = std::move(E, this->end(), S); |
| 729 | // Drop the last elts. |
| 730 | this->destroy_range(I, this->end()); |
| 731 | this->set_size(I - this->begin()); |
| 732 | return(N); |
| 733 | } |
| 734 | |
| 735 | private: |
| 736 | template <class ArgType> iterator insert_one_impl(iterator I, ArgType &&Elt) { |
| 737 | // Callers ensure that ArgType is derived from T. |
| 738 | static_assert( |
| 739 | std::is_same<std::remove_const_t<std::remove_reference_t<ArgType>>, |
| 740 | T>::value, |
| 741 | "ArgType must be derived from T!"); |
| 742 | |
| 743 | if (I == this->end()) { // Important special case for empty vector. |
| 744 | this->push_back(::std::forward<ArgType>(Elt)); |
| 745 | return this->end()-1; |
| 746 | } |
| 747 | |
| 748 | assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0); |
| 749 | |
| 750 | // Grow if necessary. |
| 751 | size_t Index = I - this->begin(); |
| 752 | std::remove_reference_t<ArgType> *EltPtr = |
| 753 | this->reserveForParamAndGetAddress(Elt); |
| 754 | I = this->begin() + Index; |
| 755 | |
| 756 | ::new ((void*) this->end()) T(::std::move(this->back())); |
| 757 | // Push everything else over. |
| 758 | std::move_backward(I, this->end()-1, this->end()); |
| 759 | this->set_size(this->size() + 1); |
| 760 | |
| 761 | // If we just moved the element we're inserting, be sure to update |
| 762 | // the reference (never happens if TakesParamByValue). |
| 763 | static_assert(!TakesParamByValue || std::is_same<ArgType, T>::value, |
| 764 | "ArgType must be 'T' when taking by value!"); |
| 765 | if (!TakesParamByValue && this->isReferenceToRange(EltPtr, I, this->end())) |
| 766 | ++EltPtr; |
| 767 | |
| 768 | *I = ::std::forward<ArgType>(*EltPtr); |
| 769 | return I; |
| 770 | } |
| 771 | |
| 772 | public: |
| 773 | iterator insert(iterator I, T &&Elt) { |
| 774 | return insert_one_impl(I, this->forward_value_param(std::move(Elt))); |
| 775 | } |
| 776 | |
| 777 | iterator insert(iterator I, const T &Elt) { |
| 778 | return insert_one_impl(I, this->forward_value_param(Elt)); |
| 779 | } |
| 780 | |
| 781 | iterator insert(iterator I, size_type NumToInsert, ValueParamT Elt) { |
| 782 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() |
| 783 | size_t InsertElt = I - this->begin(); |
| 784 | |
| 785 | if (I == this->end()) { // Important special case for empty vector. |
| 786 | append(NumToInsert, Elt); |
| 787 | return this->begin()+InsertElt; |
| 788 | } |
| 789 | |
| 790 | assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0); |
| 791 | |
| 792 | // Ensure there is enough space, and get the (maybe updated) address of |
| 793 | // Elt. |
| 794 | const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumToInsert); |
| 795 | |
| 796 | // Uninvalidate the iterator. |
| 797 | I = this->begin()+InsertElt; |
| 798 | |
| 799 | // If there are more elements between the insertion point and the end of the |
| 800 | // range than there are being inserted, we can use a simple approach to |
| 801 | // insertion. Since we already reserved space, we know that this won't |
| 802 | // reallocate the vector. |
| 803 | if (size_t(this->end()-I) >= NumToInsert) { |
| 804 | T *OldEnd = this->end(); |
| 805 | append(std::move_iterator<iterator>(this->end() - NumToInsert), |
| 806 | std::move_iterator<iterator>(this->end())); |
| 807 | |
| 808 | // Copy the existing elements that get replaced. |
| 809 | std::move_backward(I, OldEnd-NumToInsert, OldEnd); |
| 810 | |
| 811 | // If we just moved the element we're inserting, be sure to update |
| 812 | // the reference (never happens if TakesParamByValue). |
| 813 | if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end()) |
| 814 | EltPtr += NumToInsert; |
| 815 | |
| 816 | std::fill_n(I, NumToInsert, *EltPtr); |
| 817 | return I; |
| 818 | } |
| 819 | |
| 820 | // Otherwise, we're inserting more elements than exist already, and we're |
| 821 | // not inserting at the end. |
| 822 | |
| 823 | // Move over the elements that we're about to overwrite. |
| 824 | T *OldEnd = this->end(); |
| 825 | this->set_size(this->size() + NumToInsert); |
| 826 | size_t NumOverwritten = OldEnd-I; |
| 827 | this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten); |
| 828 | |
| 829 | // If we just moved the element we're inserting, be sure to update |
| 830 | // the reference (never happens if TakesParamByValue). |
| 831 | if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end()) |
| 832 | EltPtr += NumToInsert; |
| 833 | |
| 834 | // Replace the overwritten part. |
| 835 | std::fill_n(I, NumOverwritten, *EltPtr); |
| 836 | |
| 837 | // Insert the non-overwritten middle part. |
| 838 | std::uninitialized_fill_n(OldEnd, NumToInsert - NumOverwritten, *EltPtr); |
| 839 | return I; |
| 840 | } |
| 841 | |
| 842 | template <typename ItTy, |
| 843 | typename = std::enable_if_t<std::is_convertible< |
| 844 | typename std::iterator_traits<ItTy>::iterator_category, |
| 845 | std::input_iterator_tag>::value>> |
| 846 | iterator insert(iterator I, ItTy From, ItTy To) { |
| 847 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() |
| 848 | size_t InsertElt = I - this->begin(); |
| 849 | |
| 850 | if (I == this->end()) { // Important special case for empty vector. |
| 851 | append(From, To); |
| 852 | return this->begin()+InsertElt; |
| 853 | } |
| 854 | |
| 855 | assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0); |
| 856 | |
| 857 | // Check that the reserve that follows doesn't invalidate the iterators. |
| 858 | this->assertSafeToAddRange(From, To); |
| 859 | |
| 860 | size_t NumToInsert = std::distance(From, To); |
| 861 | |
| 862 | // Ensure there is enough space. |
| 863 | reserve(this->size() + NumToInsert); |
| 864 | |
| 865 | // Uninvalidate the iterator. |
| 866 | I = this->begin()+InsertElt; |
| 867 | |
| 868 | // If there are more elements between the insertion point and the end of the |
| 869 | // range than there are being inserted, we can use a simple approach to |
| 870 | // insertion. Since we already reserved space, we know that this won't |
| 871 | // reallocate the vector. |
| 872 | if (size_t(this->end()-I) >= NumToInsert) { |
| 873 | T *OldEnd = this->end(); |
| 874 | append(std::move_iterator<iterator>(this->end() - NumToInsert), |
| 875 | std::move_iterator<iterator>(this->end())); |
| 876 | |
| 877 | // Copy the existing elements that get replaced. |
| 878 | std::move_backward(I, OldEnd-NumToInsert, OldEnd); |
| 879 | |
| 880 | std::copy(From, To, I); |
| 881 | return I; |
| 882 | } |
| 883 | |
| 884 | // Otherwise, we're inserting more elements than exist already, and we're |
| 885 | // not inserting at the end. |
| 886 | |
| 887 | // Move over the elements that we're about to overwrite. |
| 888 | T *OldEnd = this->end(); |
| 889 | this->set_size(this->size() + NumToInsert); |
| 890 | size_t NumOverwritten = OldEnd-I; |
| 891 | this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten); |
| 892 | |
| 893 | // Replace the overwritten part. |
| 894 | for (T *J = I; NumOverwritten > 0; --NumOverwritten) { |
| 895 | *J = *From; |
| 896 | ++J; ++From; |
| 897 | } |
| 898 | |
| 899 | // Insert the non-overwritten middle part. |
| 900 | this->uninitialized_copy(From, To, OldEnd); |
| 901 | return I; |
| 902 | } |
| 903 | |
| 904 | void insert(iterator I, std::initializer_list<T> IL) { |
| 905 | insert(I, IL.begin(), IL.end()); |
| 906 | } |
| 907 | |
| 908 | template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) { |
| 909 | if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity ()), false)) |
| 910 | return this->growAndEmplaceBack(std::forward<ArgTypes>(Args)...); |
| 911 | |
| 912 | ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...); |
| 913 | this->set_size(this->size() + 1); |
| 914 | return this->back(); |
| 915 | } |
| 916 | |
| 917 | SmallVectorImpl &operator=(const SmallVectorImpl &RHS); |
| 918 | |
| 919 | SmallVectorImpl &operator=(SmallVectorImpl &&RHS); |
| 920 | |
| 921 | bool operator==(const SmallVectorImpl &RHS) const { |
| 922 | if (this->size() != RHS.size()) return false; |
| 923 | return std::equal(this->begin(), this->end(), RHS.begin()); |
| 924 | } |
| 925 | bool operator!=(const SmallVectorImpl &RHS) const { |
| 926 | return !(*this == RHS); |
| 927 | } |
| 928 | |
| 929 | bool operator<(const SmallVectorImpl &RHS) const { |
| 930 | return std::lexicographical_compare(this->begin(), this->end(), |
| 931 | RHS.begin(), RHS.end()); |
| 932 | } |
| 933 | }; |
| 934 | |
| 935 | template <typename T> |
| 936 | void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) { |
| 937 | if (this == &RHS) return; |
| 938 | |
| 939 | // We can only avoid copying elements if neither vector is small. |
| 940 | if (!this->isSmall() && !RHS.isSmall()) { |
| 941 | std::swap(this->BeginX, RHS.BeginX); |
| 942 | std::swap(this->Size, RHS.Size); |
| 943 | std::swap(this->Capacity, RHS.Capacity); |
| 944 | return; |
| 945 | } |
| 946 | this->reserve(RHS.size()); |
| 947 | RHS.reserve(this->size()); |
| 948 | |
| 949 | // Swap the shared elements. |
| 950 | size_t NumShared = this->size(); |
| 951 | if (NumShared > RHS.size()) NumShared = RHS.size(); |
| 952 | for (size_type i = 0; i != NumShared; ++i) |
| 953 | std::swap((*this)[i], RHS[i]); |
| 954 | |
| 955 | // Copy over the extra elts. |
| 956 | if (this->size() > RHS.size()) { |
| 957 | size_t EltDiff = this->size() - RHS.size(); |
| 958 | this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end()); |
| 959 | RHS.set_size(RHS.size() + EltDiff); |
| 960 | this->destroy_range(this->begin()+NumShared, this->end()); |
| 961 | this->set_size(NumShared); |
| 962 | } else if (RHS.size() > this->size()) { |
| 963 | size_t EltDiff = RHS.size() - this->size(); |
| 964 | this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end()); |
| 965 | this->set_size(this->size() + EltDiff); |
| 966 | this->destroy_range(RHS.begin()+NumShared, RHS.end()); |
| 967 | RHS.set_size(NumShared); |
| 968 | } |
| 969 | } |
| 970 | |
| 971 | template <typename T> |
| 972 | SmallVectorImpl<T> &SmallVectorImpl<T>:: |
| 973 | operator=(const SmallVectorImpl<T> &RHS) { |
| 974 | // Avoid self-assignment. |
| 975 | if (this == &RHS) return *this; |
| 976 | |
| 977 | // If we already have sufficient space, assign the common elements, then |
| 978 | // destroy any excess. |
| 979 | size_t RHSSize = RHS.size(); |
| 980 | size_t CurSize = this->size(); |
| 981 | if (CurSize >= RHSSize) { |
| 982 | // Assign common elements. |
| 983 | iterator NewEnd; |
| 984 | if (RHSSize) |
| 985 | NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin()); |
| 986 | else |
| 987 | NewEnd = this->begin(); |
| 988 | |
| 989 | // Destroy excess elements. |
| 990 | this->destroy_range(NewEnd, this->end()); |
| 991 | |
| 992 | // Trim. |
| 993 | this->set_size(RHSSize); |
| 994 | return *this; |
| 995 | } |
| 996 | |
| 997 | // If we have to grow to have enough elements, destroy the current elements. |
| 998 | // This allows us to avoid copying them during the grow. |
| 999 | // FIXME: don't do this if they're efficiently moveable. |
| 1000 | if (this->capacity() < RHSSize) { |
| 1001 | // Destroy current elements. |
| 1002 | this->clear(); |
| 1003 | CurSize = 0; |
| 1004 | this->grow(RHSSize); |
| 1005 | } else if (CurSize) { |
| 1006 | // Otherwise, use assignment for the already-constructed elements. |
| 1007 | std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin()); |
| 1008 | } |
| 1009 | |
| 1010 | // Copy construct the new elements in place. |
| 1011 | this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(), |
| 1012 | this->begin()+CurSize); |
| 1013 | |
| 1014 | // Set end. |
| 1015 | this->set_size(RHSSize); |
| 1016 | return *this; |
| 1017 | } |
| 1018 | |
| 1019 | template <typename T> |
| 1020 | SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) { |
| 1021 | // Avoid self-assignment. |
| 1022 | if (this == &RHS) return *this; |
| 1023 | |
| 1024 | // If the RHS isn't small, clear this vector and then steal its buffer. |
| 1025 | if (!RHS.isSmall()) { |
| 1026 | this->destroy_range(this->begin(), this->end()); |
| 1027 | if (!this->isSmall()) free(this->begin()); |
| 1028 | this->BeginX = RHS.BeginX; |
| 1029 | this->Size = RHS.Size; |
| 1030 | this->Capacity = RHS.Capacity; |
| 1031 | RHS.resetToSmall(); |
| 1032 | return *this; |
| 1033 | } |
| 1034 | |
| 1035 | // If we already have sufficient space, assign the common elements, then |
| 1036 | // destroy any excess. |
| 1037 | size_t RHSSize = RHS.size(); |
| 1038 | size_t CurSize = this->size(); |
| 1039 | if (CurSize >= RHSSize) { |
| 1040 | // Assign common elements. |
| 1041 | iterator NewEnd = this->begin(); |
| 1042 | if (RHSSize) |
| 1043 | NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd); |
| 1044 | |
| 1045 | // Destroy excess elements and trim the bounds. |
| 1046 | this->destroy_range(NewEnd, this->end()); |
| 1047 | this->set_size(RHSSize); |
| 1048 | |
| 1049 | // Clear the RHS. |
| 1050 | RHS.clear(); |
| 1051 | |
| 1052 | return *this; |
| 1053 | } |
| 1054 | |
| 1055 | // If we have to grow to have enough elements, destroy the current elements. |
| 1056 | // This allows us to avoid copying them during the grow. |
| 1057 | // FIXME: this may not actually make any sense if we can efficiently move |
| 1058 | // elements. |
| 1059 | if (this->capacity() < RHSSize) { |
| 1060 | // Destroy current elements. |
| 1061 | this->clear(); |
| 1062 | CurSize = 0; |
| 1063 | this->grow(RHSSize); |
| 1064 | } else if (CurSize) { |
| 1065 | // Otherwise, use assignment for the already-constructed elements. |
| 1066 | std::move(RHS.begin(), RHS.begin()+CurSize, this->begin()); |
| 1067 | } |
| 1068 | |
| 1069 | // Move-construct the new elements in place. |
| 1070 | this->uninitialized_move(RHS.begin()+CurSize, RHS.end(), |
| 1071 | this->begin()+CurSize); |
| 1072 | |
| 1073 | // Set end. |
| 1074 | this->set_size(RHSSize); |
| 1075 | |
| 1076 | RHS.clear(); |
| 1077 | return *this; |
| 1078 | } |
| 1079 | |
| 1080 | /// Storage for the SmallVector elements. This is specialized for the N=0 case |
| 1081 | /// to avoid allocating unnecessary storage. |
| 1082 | template <typename T, unsigned N> |
| 1083 | struct SmallVectorStorage { |
| 1084 | alignas(T) char InlineElts[N * sizeof(T)]; |
| 1085 | }; |
| 1086 | |
| 1087 | /// We need the storage to be properly aligned even for small-size of 0 so that |
| 1088 | /// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is |
| 1089 | /// well-defined. |
| 1090 | template <typename T> struct alignas(T) SmallVectorStorage<T, 0> {}; |
| 1091 | |
| 1092 | /// Forward declaration of SmallVector so that |
| 1093 | /// calculateSmallVectorDefaultInlinedElements can reference |
| 1094 | /// `sizeof(SmallVector<T, 0>)`. |
| 1095 | template <typename T, unsigned N> class LLVM_GSL_OWNER[[gsl::Owner]] SmallVector; |
| 1096 | |
| 1097 | /// Helper class for calculating the default number of inline elements for |
| 1098 | /// `SmallVector<T>`. |
| 1099 | /// |
| 1100 | /// This should be migrated to a constexpr function when our minimum |
| 1101 | /// compiler support is enough for multi-statement constexpr functions. |
| 1102 | template <typename T> struct CalculateSmallVectorDefaultInlinedElements { |
| 1103 | // Parameter controlling the default number of inlined elements |
| 1104 | // for `SmallVector<T>`. |
| 1105 | // |
| 1106 | // The default number of inlined elements ensures that |
| 1107 | // 1. There is at least one inlined element. |
| 1108 | // 2. `sizeof(SmallVector<T>) <= kPreferredSmallVectorSizeof` unless |
| 1109 | // it contradicts 1. |
| 1110 | static constexpr size_t kPreferredSmallVectorSizeof = 64; |
| 1111 | |
| 1112 | // static_assert that sizeof(T) is not "too big". |
| 1113 | // |
| 1114 | // Because our policy guarantees at least one inlined element, it is possible |
| 1115 | // for an arbitrarily large inlined element to allocate an arbitrarily large |
| 1116 | // amount of inline storage. We generally consider it an antipattern for a |
| 1117 | // SmallVector to allocate an excessive amount of inline storage, so we want |
| 1118 | // to call attention to these cases and make sure that users are making an |
| 1119 | // intentional decision if they request a lot of inline storage. |
| 1120 | // |
| 1121 | // We want this assertion to trigger in pathological cases, but otherwise |
| 1122 | // not be too easy to hit. To accomplish that, the cutoff is actually somewhat |
| 1123 | // larger than kPreferredSmallVectorSizeof (otherwise, |
| 1124 | // `SmallVector<SmallVector<T>>` would be one easy way to trip it, and that |
| 1125 | // pattern seems useful in practice). |
| 1126 | // |
| 1127 | // One wrinkle is that this assertion is in theory non-portable, since |
| 1128 | // sizeof(T) is in general platform-dependent. However, we don't expect this |
| 1129 | // to be much of an issue, because most LLVM development happens on 64-bit |
| 1130 | // hosts, and therefore sizeof(T) is expected to *decrease* when compiled for |
| 1131 | // 32-bit hosts, dodging the issue. The reverse situation, where development |
| 1132 | // happens on a 32-bit host and then fails due to sizeof(T) *increasing* on a |
| 1133 | // 64-bit host, is expected to be very rare. |
| 1134 | static_assert( |
| 1135 | sizeof(T) <= 256, |
| 1136 | "You are trying to use a default number of inlined elements for " |
| 1137 | "`SmallVector<T>` but `sizeof(T)` is really big! Please use an " |
| 1138 | "explicit number of inlined elements with `SmallVector<T, N>` to make " |
| 1139 | "sure you really want that much inline storage."); |
| 1140 | |
| 1141 | // Discount the size of the header itself when calculating the maximum inline |
| 1142 | // bytes. |
| 1143 | static constexpr size_t PreferredInlineBytes = |
| 1144 | kPreferredSmallVectorSizeof - sizeof(SmallVector<T, 0>); |
| 1145 | static constexpr size_t NumElementsThatFit = PreferredInlineBytes / sizeof(T); |
| 1146 | static constexpr size_t value = |
| 1147 | NumElementsThatFit == 0 ? 1 : NumElementsThatFit; |
| 1148 | }; |
| 1149 | |
| 1150 | /// This is a 'vector' (really, a variable-sized array), optimized |
| 1151 | /// for the case when the array is small. It contains some number of elements |
| 1152 | /// in-place, which allows it to avoid heap allocation when the actual number of |
| 1153 | /// elements is below that threshold. This allows normal "small" cases to be |
| 1154 | /// fast without losing generality for large inputs. |
| 1155 | /// |
| 1156 | /// \note |
| 1157 | /// In the absence of a well-motivated choice for the number of inlined |
| 1158 | /// elements \p N, it is recommended to use \c SmallVector<T> (that is, |
| 1159 | /// omitting the \p N). This will choose a default number of inlined elements |
| 1160 | /// reasonable for allocation on the stack (for example, trying to keep \c |
| 1161 | /// sizeof(SmallVector<T>) around 64 bytes). |
| 1162 | /// |
| 1163 | /// \warning This does not attempt to be exception safe. |
| 1164 | /// |
| 1165 | /// \see https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h |
| 1166 | template <typename T, |
| 1167 | unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value> |
| 1168 | class LLVM_GSL_OWNER[[gsl::Owner]] SmallVector : public SmallVectorImpl<T>, |
| 1169 | SmallVectorStorage<T, N> { |
| 1170 | public: |
| 1171 | SmallVector() : SmallVectorImpl<T>(N) {} |
| 1172 | |
| 1173 | ~SmallVector() { |
| 1174 | // Destroy the constructed elements in the vector. |
| 1175 | this->destroy_range(this->begin(), this->end()); |
| 1176 | } |
| 1177 | |
| 1178 | explicit SmallVector(size_t Size, const T &Value = T()) |
| 1179 | : SmallVectorImpl<T>(N) { |
| 1180 | this->assign(Size, Value); |
| 1181 | } |
| 1182 | |
| 1183 | template <typename ItTy, |
| 1184 | typename = std::enable_if_t<std::is_convertible< |
| 1185 | typename std::iterator_traits<ItTy>::iterator_category, |
| 1186 | std::input_iterator_tag>::value>> |
| 1187 | SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) { |
| 1188 | this->append(S, E); |
| 1189 | } |
| 1190 | |
| 1191 | template <typename RangeTy> |
| 1192 | explicit SmallVector(const iterator_range<RangeTy> &R) |
| 1193 | : SmallVectorImpl<T>(N) { |
| 1194 | this->append(R.begin(), R.end()); |
| 1195 | } |
| 1196 | |
| 1197 | SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) { |
| 1198 | this->assign(IL); |
| 1199 | } |
| 1200 | |
| 1201 | SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) { |
| 1202 | if (!RHS.empty()) |
| 1203 | SmallVectorImpl<T>::operator=(RHS); |
| 1204 | } |
| 1205 | |
| 1206 | SmallVector &operator=(const SmallVector &RHS) { |
| 1207 | SmallVectorImpl<T>::operator=(RHS); |
| 1208 | return *this; |
| 1209 | } |
| 1210 | |
| 1211 | SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) { |
| 1212 | if (!RHS.empty()) |
| 1213 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
| 1214 | } |
| 1215 | |
| 1216 | SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) { |
| 1217 | if (!RHS.empty()) |
| 1218 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
| 1219 | } |
| 1220 | |
| 1221 | SmallVector &operator=(SmallVector &&RHS) { |
| 1222 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
| 1223 | return *this; |
| 1224 | } |
| 1225 | |
| 1226 | SmallVector &operator=(SmallVectorImpl<T> &&RHS) { |
| 1227 | SmallVectorImpl<T>::operator=(::std::move(RHS)); |
| 1228 | return *this; |
| 1229 | } |
| 1230 | |
| 1231 | SmallVector &operator=(std::initializer_list<T> IL) { |
| 1232 | this->assign(IL); |
| 1233 | return *this; |
| 1234 | } |
| 1235 | }; |
| 1236 | |
| 1237 | template <typename T, unsigned N> |
| 1238 | inline size_t capacity_in_bytes(const SmallVector<T, N> &X) { |
| 1239 | return X.capacity_in_bytes(); |
| 1240 | } |
| 1241 | |
| 1242 | /// Given a range of type R, iterate the entire range and return a |
| 1243 | /// SmallVector with elements of the vector. This is useful, for example, |
| 1244 | /// when you want to iterate a range and then sort the results. |
| 1245 | template <unsigned Size, typename R> |
| 1246 | SmallVector<typename std::remove_const<typename std::remove_reference< |
| 1247 | decltype(*std::begin(std::declval<R &>()))>::type>::type, |
| 1248 | Size> |
| 1249 | to_vector(R &&Range) { |
| 1250 | return {std::begin(Range), std::end(Range)}; |
| 1251 | } |
| 1252 | |
| 1253 | } // end namespace llvm |
| 1254 | |
| 1255 | namespace std { |
| 1256 | |
| 1257 | /// Implement std::swap in terms of SmallVector swap. |
| 1258 | template<typename T> |
| 1259 | inline void |
| 1260 | swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) { |
| 1261 | LHS.swap(RHS); |
| 1262 | } |
| 1263 | |
| 1264 | /// Implement std::swap in terms of SmallVector swap. |
| 1265 | template<typename T, unsigned N> |
| 1266 | inline void |
| 1267 | swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) { |
| 1268 | LHS.swap(RHS); |
| 1269 | } |
| 1270 | |
| 1271 | } // end namespace std |
| 1272 | |
| 1273 | #endif // LLVM_ADT_SMALLVECTOR_H |