Bug Summary

File:src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support/Alignment.h
Warning:line 85, column 47
The result of the left shift is undefined due to shifting by '255', which is greater or equal to the width of type 'uint64_t'

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name AssumeBundleBuilder.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Analysis -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ASMParser -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/BinaryFormat -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitcode -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitcode -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitstream -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /include/llvm/CodeGen -I /include/llvm/CodeGen/PBQP -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/IR -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IR -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Coroutines -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData/Coverage -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/CodeView -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/DWARF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/MSF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/PDB -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Demangle -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/JITLink -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/Orc -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenACC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenMP -I /include/llvm/CodeGen/GlobalISel -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IRReader -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/LTO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Linker -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC/MCParser -I /include/llvm/CodeGen/MIRParser -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Object -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Option -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Passes -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Scalar -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ADT -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/Symbolize -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Target -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Utils -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Vectorize -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/IPO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libLLVM/../include -I /usr/src/gnu/usr.bin/clang/libLLVM/obj -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -D PIC -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -D_RET_PROTECTOR -ret-protector -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp

→
1//===- AssumeBundleBuilder.cpp - tools to preserve informations -*- 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#include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
10#include "llvm/ADT/DepthFirstIterator.h"
11#include "llvm/ADT/MapVector.h"
12#include "llvm/ADT/Statistic.h"
13#include "llvm/Analysis/AssumeBundleQueries.h"
14#include "llvm/Analysis/AssumptionCache.h"
15#include "llvm/Analysis/ValueTracking.h"
16#include "llvm/IR/Dominators.h"
17#include "llvm/IR/Function.h"
18#include "llvm/IR/InstIterator.h"
19#include "llvm/IR/IntrinsicInst.h"
20#include "llvm/IR/Module.h"
21#include "llvm/InitializePasses.h"
22#include "llvm/Support/CommandLine.h"
23#include "llvm/Support/DebugCounter.h"
24#include "llvm/Transforms/Utils/Local.h"
25
26using namespace llvm;
27
28namespace llvm {
29cl::opt<bool> ShouldPreserveAllAttributes(
30 "assume-preserve-all", cl::init(false), cl::Hidden,
31 cl::desc("enable preservation of all attrbitues. even those that are "
32 "unlikely to be usefull"));
33
34cl::opt<bool> EnableKnowledgeRetention(
35 "enable-knowledge-retention", cl::init(false), cl::Hidden,
36 cl::desc(
37 "enable preservation of attributes throughout code transformation"));
38} // namespace llvm
39
40#define DEBUG_TYPE"assume-builder" "assume-builder"
41
42STATISTIC(NumAssumeBuilt, "Number of assume built by the assume builder")static llvm::Statistic NumAssumeBuilt = {"assume-builder", "NumAssumeBuilt"
, "Number of assume built by the assume builder"};
43STATISTIC(NumBundlesInAssumes, "Total number of Bundles in the assume built")static llvm::Statistic NumBundlesInAssumes = {"assume-builder"
, "NumBundlesInAssumes", "Total number of Bundles in the assume built"
};
44STATISTIC(NumAssumesMerged,static llvm::Statistic NumAssumesMerged = {"assume-builder", "NumAssumesMerged"
, "Number of assume merged by the assume simplify pass"}
45 "Number of assume merged by the assume simplify pass")static llvm::Statistic NumAssumesMerged = {"assume-builder", "NumAssumesMerged"
, "Number of assume merged by the assume simplify pass"};
46STATISTIC(NumAssumesRemoved,static llvm::Statistic NumAssumesRemoved = {"assume-builder",
"NumAssumesRemoved", "Number of assume removed by the assume simplify pass"
}
47 "Number of assume removed by the assume simplify pass")static llvm::Statistic NumAssumesRemoved = {"assume-builder",
"NumAssumesRemoved", "Number of assume removed by the assume simplify pass"
};
48
49DEBUG_COUNTER(BuildAssumeCounter, "assume-builder-counter",static const unsigned BuildAssumeCounter = DebugCounter::registerCounter
("assume-builder-counter", "Controls which assumes gets created"
)
50 "Controls which assumes gets created")static const unsigned BuildAssumeCounter = DebugCounter::registerCounter
("assume-builder-counter", "Controls which assumes gets created"
);
51
52namespace {
53
54bool isUsefullToPreserve(Attribute::AttrKind Kind) {
55 switch (Kind) {
56 case Attribute::NonNull:
57 case Attribute::NoUndef:
58 case Attribute::Alignment:
59 case Attribute::Dereferenceable:
60 case Attribute::DereferenceableOrNull:
61 case Attribute::Cold:
62 return true;
63 default:
64 return false;
65 }
66}
67
68/// This function will try to transform the given knowledge into a more
69/// canonical one. the canonical knowledge maybe the given one.
70RetainedKnowledge canonicalizedKnowledge(RetainedKnowledge RK, DataLayout DL) {
71 switch (RK.AttrKind) {
72 default:
73 return RK;
74 case Attribute::NonNull:
75 RK.WasOn = getUnderlyingObject(RK.WasOn);
76 return RK;
77 case Attribute::Alignment: {
78 Value *V = RK.WasOn->stripInBoundsOffsets([&](const Value *Strip) {
79 if (auto *GEP = dyn_cast<GEPOperator>(Strip))
80 RK.ArgValue =
81 MinAlign(RK.ArgValue, GEP->getMaxPreservedAlignment(DL).value());
82 });
83 RK.WasOn = V;
84 return RK;
85 }
86 case Attribute::Dereferenceable:
87 case Attribute::DereferenceableOrNull: {
88 int64_t Offset = 0;
89 Value *V = GetPointerBaseWithConstantOffset(RK.WasOn, Offset, DL,
90 /*AllowNonInBounds*/ false);
91 if (Offset < 0)
92 return RK;
93 RK.ArgValue = RK.ArgValue + Offset;
94 RK.WasOn = V;
95 }
96 }
97 return RK;
98}
99
100/// This class contain all knowledge that have been gather while building an
101/// llvm.assume and the function to manipulate it.
102struct AssumeBuilderState {
103 Module *M;
104
105 using MapKey = std::pair<Value *, Attribute::AttrKind>;
106 SmallMapVector<MapKey, unsigned, 8> AssumedKnowledgeMap;
107 Instruction *InstBeingModified = nullptr;
108 AssumptionCache* AC = nullptr;
109 DominatorTree* DT = nullptr;
110
111 AssumeBuilderState(Module *M, Instruction *I = nullptr,
112 AssumptionCache *AC = nullptr, DominatorTree *DT = nullptr)
113 : M(M), InstBeingModified(I), AC(AC), DT(DT) {}
114
115 bool tryToPreserveWithoutAddingAssume(RetainedKnowledge RK) {
116 if (!InstBeingModified || !RK.WasOn)
117 return false;
118 bool HasBeenPreserved = false;
119 Use* ToUpdate = nullptr;
120 getKnowledgeForValue(
121 RK.WasOn, {RK.AttrKind}, AC,
122 [&](RetainedKnowledge RKOther, Instruction *Assume,
123 const CallInst::BundleOpInfo *Bundle) {
124 if (!isValidAssumeForContext(Assume, InstBeingModified, DT))
125 return false;
126 if (RKOther.ArgValue >= RK.ArgValue) {
127 HasBeenPreserved = true;
128 return true;
129 } else if (isValidAssumeForContext(InstBeingModified, Assume, DT)) {
130 HasBeenPreserved = true;
131 IntrinsicInst *Intr = cast<IntrinsicInst>(Assume);
132 ToUpdate = &Intr->op_begin()[Bundle->Begin + ABA_Argument];
133 return true;
134 }
135 return false;
136 });
137 if (ToUpdate)
138 ToUpdate->set(
139 ConstantInt::get(Type::getInt64Ty(M->getContext()), RK.ArgValue));
140 return HasBeenPreserved;
141 }
142
143 bool isKnowledgeWorthPreserving(RetainedKnowledge RK) {
144 if (!RK)
145 return false;
146 if (!RK.WasOn)
147 return true;
148 if (RK.WasOn->getType()->isPointerTy()) {
149 Value *UnderlyingPtr = getUnderlyingObject(RK.WasOn);
150 if (isa<AllocaInst>(UnderlyingPtr) || isa<GlobalValue>(UnderlyingPtr))
151 return false;
152 }
153 if (auto *Arg = dyn_cast<Argument>(RK.WasOn)) {
154 if (Arg->hasAttribute(RK.AttrKind) &&
155 (!Attribute::isIntAttrKind(RK.AttrKind) ||
156 Arg->getAttribute(RK.AttrKind).getValueAsInt() >= RK.ArgValue))
157 return false;
158 return true;
159 }
160 if (auto *Inst = dyn_cast<Instruction>(RK.WasOn))
161 if (wouldInstructionBeTriviallyDead(Inst)) {
162 if (RK.WasOn->use_empty())
163 return false;
164 Use *SingleUse = RK.WasOn->getSingleUndroppableUse();
165 if (SingleUse && SingleUse->getUser() == InstBeingModified)
166 return false;
167 }
168 return true;
169 }
170
171 void addKnowledge(RetainedKnowledge RK) {
172 RK = canonicalizedKnowledge(RK, M->getDataLayout());
173
174 if (!isKnowledgeWorthPreserving(RK))
175 return;
176
177 if (tryToPreserveWithoutAddingAssume(RK))
178 return;
179 MapKey Key{RK.WasOn, RK.AttrKind};
180 auto Lookup = AssumedKnowledgeMap.find(Key);
181 if (Lookup == AssumedKnowledgeMap.end()) {
182 AssumedKnowledgeMap[Key] = RK.ArgValue;
183 return;
184 }
185 assert(((Lookup->second == 0 && RK.ArgValue == 0) ||((void)0)
186 (Lookup->second != 0 && RK.ArgValue != 0)) &&((void)0)
187 "inconsistent argument value")((void)0);
188
189 /// This is only desirable because for all attributes taking an argument
190 /// higher is better.
191 Lookup->second = std::max(Lookup->second, RK.ArgValue);
192 }
193
194 void addAttribute(Attribute Attr, Value *WasOn) {
195 if (Attr.isTypeAttribute() || Attr.isStringAttribute() ||
196 (!ShouldPreserveAllAttributes &&
197 !isUsefullToPreserve(Attr.getKindAsEnum())))
198 return;
199 unsigned AttrArg = 0;
200 if (Attr.isIntAttribute())
201 AttrArg = Attr.getValueAsInt();
202 addKnowledge({Attr.getKindAsEnum(), AttrArg, WasOn});
203 }
204
205 void addCall(const CallBase *Call) {
206 auto addAttrList = [&](AttributeList AttrList) {
207 for (unsigned Idx = AttributeList::FirstArgIndex;
208 Idx < AttrList.getNumAttrSets(); Idx++)
209 for (Attribute Attr : AttrList.getAttributes(Idx)) {
210 bool IsPoisonAttr = Attr.hasAttribute(Attribute::NonNull) ||
211 Attr.hasAttribute(Attribute::Alignment);
212 if (!IsPoisonAttr || Call->isPassingUndefUB(Idx - 1))
213 addAttribute(Attr, Call->getArgOperand(Idx - 1));
214 }
215 for (Attribute Attr : AttrList.getFnAttributes())
216 addAttribute(Attr, nullptr);
217 };
218 addAttrList(Call->getAttributes());
219 if (Function *Fn = Call->getCalledFunction())
220 addAttrList(Fn->getAttributes());
221 }
222
223 AssumeInst *build() {
224 if (AssumedKnowledgeMap.empty())
225 return nullptr;
226 if (!DebugCounter::shouldExecute(BuildAssumeCounter))
227 return nullptr;
228 Function *FnAssume = Intrinsic::getDeclaration(M, Intrinsic::assume);
229 LLVMContext &C = M->getContext();
230 SmallVector<OperandBundleDef, 8> OpBundle;
231 for (auto &MapElem : AssumedKnowledgeMap) {
232 SmallVector<Value *, 2> Args;
233 if (MapElem.first.first)
234 Args.push_back(MapElem.first.first);
235
236 /// This is only valid because for all attribute that currently exist a
237 /// value of 0 is useless. and should not be preserved.
238 if (MapElem.second)
239 Args.push_back(ConstantInt::get(Type::getInt64Ty(M->getContext()),
240 MapElem.second));
241 OpBundle.push_back(OperandBundleDefT<Value *>(
242 std::string(Attribute::getNameFromAttrKind(MapElem.first.second)),
243 Args));
244 NumBundlesInAssumes++;
245 }
246 NumAssumeBuilt++;
247 return cast<AssumeInst>(CallInst::Create(
248 FnAssume, ArrayRef<Value *>({ConstantInt::getTrue(C)}), OpBundle));
249 }
250
251 void addAccessedPtr(Instruction *MemInst, Value *Pointer, Type *AccType,
252 MaybeAlign MA) {
253 unsigned DerefSize = MemInst->getModule()
254 ->getDataLayout()
255 .getTypeStoreSize(AccType)
256 .getKnownMinSize();
257 if (DerefSize != 0) {
10
←
Assuming 'DerefSize' is equal to 0
→
11
←
Taking false branch
→
258 addKnowledge({Attribute::Dereferenceable, DerefSize, Pointer});
259 if (!NullPointerIsDefined(MemInst->getFunction(),
260 Pointer->getType()->getPointerAddressSpace()))
261 addKnowledge({Attribute::NonNull, 0u, Pointer});
262 }
263 if (MA.valueOrOne() > 1)
12
←
Calling 'MaybeAlign::valueOrOne'
→
15
←
Returning from 'MaybeAlign::valueOrOne'
→
16
←
Calling 'operator>'
→
264 addKnowledge(
265 {Attribute::Alignment, unsigned(MA.valueOrOne().value()), Pointer});
266 }
267
268 void addInstruction(Instruction *I) {
269 if (auto *Call
5.1
'Call' is null
5.1
'Call' is null
 = dyn_cast<CallBase>(I))
5
←
Assuming 'I' is not a 'CallBase'
→
6
←
Taking false branch
→
270 return addCall(Call);
271 if (auto *Load
7.1
'Load' is non-null
7.1
'Load' is non-null
 = dyn_cast<LoadInst>(I))
7
←
Assuming 'I' is a 'LoadInst'
→
8
←
Taking true branch
→
272 return addAccessedPtr(I, Load->getPointerOperand(), Load->getType(),
9
←
Calling 'AssumeBuilderState::addAccessedPtr'
→
273 Load->getAlign());
274 if (auto *Store = dyn_cast<StoreInst>(I))
275 return addAccessedPtr(I, Store->getPointerOperand(),
276 Store->getValueOperand()->getType(),
277 Store->getAlign());
278 // TODO: Add support for the other Instructions.
279 // TODO: Maybe we should look around and merge with other llvm.assume.
280 }
281};
282
283} // namespace
284
285AssumeInst *llvm::buildAssumeFromInst(Instruction *I) {
286 if (!EnableKnowledgeRetention)
287 return nullptr;
288 AssumeBuilderState Builder(I->getModule());
289 Builder.addInstruction(I);
290 return Builder.build();
291}
292
293void llvm::salvageKnowledge(Instruction *I, AssumptionCache *AC,
294 DominatorTree *DT) {
295 if (!EnableKnowledgeRetention || I->isTerminator())
2
←
Assuming the condition is false
→
3
←
Taking false branch
→
296 return;
297 AssumeBuilderState Builder(I->getModule(), I, AC, DT);
298 Builder.addInstruction(I);
4
←
Calling 'AssumeBuilderState::addInstruction'
→
299 if (auto *Intr = Builder.build()) {
300 Intr->insertBefore(I);
301 if (AC)
302 AC->registerAssumption(Intr);
303 }
304}
305
306AssumeInst *
307llvm::buildAssumeFromKnowledge(ArrayRef<RetainedKnowledge> Knowledge,
308 Instruction *CtxI, AssumptionCache *AC,
309 DominatorTree *DT) {
310 AssumeBuilderState Builder(CtxI->getModule(), CtxI, AC, DT);
311 for (const RetainedKnowledge &RK : Knowledge)
312 Builder.addKnowledge(RK);
313 return Builder.build();
314}
315
316RetainedKnowledge llvm::simplifyRetainedKnowledge(AssumeInst *Assume,
317 RetainedKnowledge RK,
318 AssumptionCache *AC,
319 DominatorTree *DT) {
320 AssumeBuilderState Builder(Assume->getModule(), Assume, AC, DT);
321 RK = canonicalizedKnowledge(RK, Assume->getModule()->getDataLayout());
322
323 if (!Builder.isKnowledgeWorthPreserving(RK))
324 return RetainedKnowledge::none();
325
326 if (Builder.tryToPreserveWithoutAddingAssume(RK))
327 return RetainedKnowledge::none();
328 return RK;
329}
330
331namespace {
332
333struct AssumeSimplify {
334 Function &F;
335 AssumptionCache &AC;
336 DominatorTree *DT;
337 LLVMContext &C;
338 SmallDenseSet<IntrinsicInst *> CleanupToDo;
339 StringMapEntry<uint32_t> *IgnoreTag;
340 SmallDenseMap<BasicBlock *, SmallVector<IntrinsicInst *, 4>, 8> BBToAssume;
341 bool MadeChange = false;
342
343 AssumeSimplify(Function &F, AssumptionCache &AC, DominatorTree *DT,
344 LLVMContext &C)
345 : F(F), AC(AC), DT(DT), C(C),
346 IgnoreTag(C.getOrInsertBundleTag(IgnoreBundleTag)) {}
347
348 void buildMapping(bool FilterBooleanArgument) {
349 BBToAssume.clear();
350 for (Value *V : AC.assumptions()) {
351 if (!V)
352 continue;
353 IntrinsicInst *Assume = cast<IntrinsicInst>(V);
354 if (FilterBooleanArgument) {
355 auto *Arg = dyn_cast<ConstantInt>(Assume->getOperand(0));
356 if (!Arg || Arg->isZero())
357 continue;
358 }
359 BBToAssume[Assume->getParent()].push_back(Assume);
360 }
361
362 for (auto &Elem : BBToAssume) {
363 llvm::sort(Elem.second,
364 [](const IntrinsicInst *LHS, const IntrinsicInst *RHS) {
365 return LHS->comesBefore(RHS);
366 });
367 }
368 }
369
370 /// Remove all asumes in CleanupToDo if there boolean argument is true and
371 /// ForceCleanup is set or the assume doesn't hold valuable knowledge.
372 void RunCleanup(bool ForceCleanup) {
373 for (IntrinsicInst *Assume : CleanupToDo) {
374 auto *Arg = dyn_cast<ConstantInt>(Assume->getOperand(0));
375 if (!Arg || Arg->isZero() ||
376 (!ForceCleanup &&
377 !isAssumeWithEmptyBundle(cast<AssumeInst>(*Assume))))
378 continue;
379 MadeChange = true;
380 if (ForceCleanup)
381 NumAssumesMerged++;
382 else
383 NumAssumesRemoved++;
384 Assume->eraseFromParent();
385 }
386 CleanupToDo.clear();
387 }
388
389 /// Remove knowledge stored in assume when it is already know by an attribute
390 /// or an other assume. This can when valid update an existing knowledge in an
391 /// attribute or an other assume.
392 void dropRedundantKnowledge() {
393 struct MapValue {
394 IntrinsicInst *Assume;
395 unsigned ArgValue;
396 CallInst::BundleOpInfo *BOI;
397 };
398 buildMapping(false);
399 SmallDenseMap<std::pair<Value *, Attribute::AttrKind>,
400 SmallVector<MapValue, 2>, 16>
401 Knowledge;
402 for (BasicBlock *BB : depth_first(&F))
403 for (Value *V : BBToAssume[BB]) {
404 if (!V)
405 continue;
406 IntrinsicInst *Assume = cast<IntrinsicInst>(V);
407 for (CallInst::BundleOpInfo &BOI : Assume->bundle_op_infos()) {
408 auto RemoveFromAssume = [&]() {
409 CleanupToDo.insert(Assume);
410 if (BOI.Begin != BOI.End) {
411 Use *U = &Assume->op_begin()[BOI.Begin + ABA_WasOn];
412 U->set(UndefValue::get(U->get()->getType()));
413 }
414 BOI.Tag = IgnoreTag;
415 };
416 if (BOI.Tag == IgnoreTag) {
417 CleanupToDo.insert(Assume);
418 continue;
419 }
420 RetainedKnowledge RK =
421 getKnowledgeFromBundle(cast<AssumeInst>(*Assume), BOI);
422 if (auto *Arg = dyn_cast_or_null<Argument>(RK.WasOn)) {
423 bool HasSameKindAttr = Arg->hasAttribute(RK.AttrKind);
424 if (HasSameKindAttr)
425 if (!Attribute::isIntAttrKind(RK.AttrKind) ||
426 Arg->getAttribute(RK.AttrKind).getValueAsInt() >=
427 RK.ArgValue) {
428 RemoveFromAssume();
429 continue;
430 }
431 if (isValidAssumeForContext(
432 Assume, &*F.getEntryBlock().getFirstInsertionPt()) ||
433 Assume == &*F.getEntryBlock().getFirstInsertionPt()) {
434 if (HasSameKindAttr)
435 Arg->removeAttr(RK.AttrKind);
436 Arg->addAttr(Attribute::get(C, RK.AttrKind, RK.ArgValue));
437 MadeChange = true;
438 RemoveFromAssume();
439 continue;
440 }
441 }
442 auto &Lookup = Knowledge[{RK.WasOn, RK.AttrKind}];
443 for (MapValue &Elem : Lookup) {
444 if (!isValidAssumeForContext(Elem.Assume, Assume, DT))
445 continue;
446 if (Elem.ArgValue >= RK.ArgValue) {
447 RemoveFromAssume();
448 continue;
449 } else if (isValidAssumeForContext(Assume, Elem.Assume, DT)) {
450 Elem.Assume->op_begin()[Elem.BOI->Begin + ABA_Argument].set(
451 ConstantInt::get(Type::getInt64Ty(C), RK.ArgValue));
452 MadeChange = true;
453 RemoveFromAssume();
454 continue;
455 }
456 }
457 Lookup.push_back({Assume, RK.ArgValue, &BOI});
458 }
459 }
460 }
461
462 using MergeIterator = SmallVectorImpl<IntrinsicInst *>::iterator;
463
464 /// Merge all Assumes from Begin to End in and insert the resulting assume as
465 /// high as possible in the basicblock.
466 void mergeRange(BasicBlock *BB, MergeIterator Begin, MergeIterator End) {
467 if (Begin == End || std::next(Begin) == End)
468 return;
469 /// Provide no additional information so that AssumeBuilderState doesn't
470 /// try to do any punning since it already has been done better.
471 AssumeBuilderState Builder(F.getParent());
472
473 /// For now it is initialized to the best value it could have
474 Instruction *InsertPt = BB->getFirstNonPHI();
475 if (isa<LandingPadInst>(InsertPt))
476 InsertPt = InsertPt->getNextNode();
477 for (IntrinsicInst *I : make_range(Begin, End)) {
478 CleanupToDo.insert(I);
479 for (CallInst::BundleOpInfo &BOI : I->bundle_op_infos()) {
480 RetainedKnowledge RK =
481 getKnowledgeFromBundle(cast<AssumeInst>(*I), BOI);
482 if (!RK)
483 continue;
484 Builder.addKnowledge(RK);
485 if (auto *I = dyn_cast_or_null<Instruction>(RK.WasOn))
486 if (I->getParent() == InsertPt->getParent() &&
487 (InsertPt->comesBefore(I) || InsertPt == I))
488 InsertPt = I->getNextNode();
489 }
490 }
491
492 /// Adjust InsertPt if it is before Begin, since mergeAssumes only
493 /// guarantees we can place the resulting assume between Begin and End.
494 if (InsertPt->comesBefore(*Begin))
495 for (auto It = (*Begin)->getIterator(), E = InsertPt->getIterator();
496 It != E; --It)
497 if (!isGuaranteedToTransferExecutionToSuccessor(&*It)) {
498 InsertPt = It->getNextNode();
499 break;
500 }
501 auto *MergedAssume = Builder.build();
502 if (!MergedAssume)
503 return;
504 MadeChange = true;
505 MergedAssume->insertBefore(InsertPt);
506 AC.registerAssumption(MergedAssume);
507 }
508
509 /// Merge assume when they are in the same BasicBlock and for all instruction
510 /// between them isGuaranteedToTransferExecutionToSuccessor returns true.
511 void mergeAssumes() {
512 buildMapping(true);
513
514 SmallVector<MergeIterator, 4> SplitPoints;
515 for (auto &Elem : BBToAssume) {
516 SmallVectorImpl<IntrinsicInst *> &AssumesInBB = Elem.second;
517 if (AssumesInBB.size() < 2)
518 continue;
519 /// AssumesInBB is already sorted by order in the block.
520
521 BasicBlock::iterator It = AssumesInBB.front()->getIterator();
522 BasicBlock::iterator E = AssumesInBB.back()->getIterator();
523 SplitPoints.push_back(AssumesInBB.begin());
524 MergeIterator LastSplit = AssumesInBB.begin();
525 for (; It != E; ++It)
526 if (!isGuaranteedToTransferExecutionToSuccessor(&*It)) {
527 for (; (*LastSplit)->comesBefore(&*It); ++LastSplit)
528 ;
529 if (SplitPoints.back() != LastSplit)
530 SplitPoints.push_back(LastSplit);
531 }
532 SplitPoints.push_back(AssumesInBB.end());
533 for (auto SplitIt = SplitPoints.begin();
534 SplitIt != std::prev(SplitPoints.end()); SplitIt++) {
535 mergeRange(Elem.first, *SplitIt, *(SplitIt + 1));
536 }
537 SplitPoints.clear();
538 }
539 }
540};
541
542bool simplifyAssumes(Function &F, AssumptionCache *AC, DominatorTree *DT) {
543 AssumeSimplify AS(F, *AC, DT, F.getContext());
544
545 /// Remove knowledge that is already known by a dominating other assume or an
546 /// attribute.
547 AS.dropRedundantKnowledge();
548
549 /// Remove assume that are empty.
550 AS.RunCleanup(false);
551
552 /// Merge assume in the same basicblock when possible.
553 AS.mergeAssumes();
554
555 /// Remove assume that were merged.
556 AS.RunCleanup(true);
557 return AS.MadeChange;
558}
559
560} // namespace
561
562PreservedAnalyses AssumeSimplifyPass::run(Function &F,
563 FunctionAnalysisManager &AM) {
564 if (!EnableKnowledgeRetention)
565 return PreservedAnalyses::all();
566 simplifyAssumes(F, &AM.getResult<AssumptionAnalysis>(F),
567 AM.getCachedResult<DominatorTreeAnalysis>(F));
568 return PreservedAnalyses::all();
569}
570
571namespace {
572class AssumeSimplifyPassLegacyPass : public FunctionPass {
573public:
574 static char ID;
575
576 AssumeSimplifyPassLegacyPass() : FunctionPass(ID) {
577 initializeAssumeSimplifyPassLegacyPassPass(
578 *PassRegistry::getPassRegistry());
579 }
580 bool runOnFunction(Function &F) override {
581 if (skipFunction(F) || !EnableKnowledgeRetention)
582 return false;
583 AssumptionCache &AC =
584 getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
585 DominatorTreeWrapperPass *DTWP =
586 getAnalysisIfAvailable<DominatorTreeWrapperPass>();
587 return simplifyAssumes(F, &AC, DTWP ? &DTWP->getDomTree() : nullptr);
588 }
589
590 void getAnalysisUsage(AnalysisUsage &AU) const override {
591 AU.addRequired<AssumptionCacheTracker>();
592
593 AU.setPreservesAll();
594 }
595};
596} // namespace
597
598char AssumeSimplifyPassLegacyPass::ID = 0;
599
600INITIALIZE_PASS_BEGIN(AssumeSimplifyPassLegacyPass, "assume-simplify",static void *initializeAssumeSimplifyPassLegacyPassPassOnce(PassRegistry
&Registry) {
601 "Assume Simplify", false, false)static void *initializeAssumeSimplifyPassLegacyPassPassOnce(PassRegistry
&Registry) {
602INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
603INITIALIZE_PASS_END(AssumeSimplifyPassLegacyPass, "assume-simplify",PassInfo *PI = new PassInfo( "Assume Simplify", "assume-simplify"
, &AssumeSimplifyPassLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<AssumeSimplifyPassLegacyPass>), false,
false); Registry.registerPass(*PI, true); return PI; } static
llvm::once_flag InitializeAssumeSimplifyPassLegacyPassPassFlag
; void llvm::initializeAssumeSimplifyPassLegacyPassPass(PassRegistry
&Registry) { llvm::call_once(InitializeAssumeSimplifyPassLegacyPassPassFlag
, initializeAssumeSimplifyPassLegacyPassPassOnce, std::ref(Registry
)); }
604 "Assume Simplify", false, false)PassInfo *PI = new PassInfo( "Assume Simplify", "assume-simplify"
, &AssumeSimplifyPassLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<AssumeSimplifyPassLegacyPass>), false,
false); Registry.registerPass(*PI, true); return PI; } static
llvm::once_flag InitializeAssumeSimplifyPassLegacyPassPassFlag
; void llvm::initializeAssumeSimplifyPassLegacyPassPass(PassRegistry
&Registry) { llvm::call_once(InitializeAssumeSimplifyPassLegacyPassPassFlag
, initializeAssumeSimplifyPassLegacyPassPassOnce, std::ref(Registry
)); }
605
606FunctionPass *llvm::createAssumeSimplifyPass() {
607 return new AssumeSimplifyPassLegacyPass();
608}
609
610PreservedAnalyses AssumeBuilderPass::run(Function &F,
611 FunctionAnalysisManager &AM) {
612 AssumptionCache *AC = &AM.getResult<AssumptionAnalysis>(F);
613 DominatorTree* DT = AM.getCachedResult<DominatorTreeAnalysis>(F);
614 for (Instruction &I : instructions(F))
615 salvageKnowledge(&I, AC, DT);
1
Calling 'salvageKnowledge'
→
616 return PreservedAnalyses::all();
617}
618
619namespace {
620class AssumeBuilderPassLegacyPass : public FunctionPass {
621public:
622 static char ID;
623
624 AssumeBuilderPassLegacyPass() : FunctionPass(ID) {
625 initializeAssumeBuilderPassLegacyPassPass(*PassRegistry::getPassRegistry());
626 }
627 bool runOnFunction(Function &F) override {
628 AssumptionCache &AC =
629 getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
630 DominatorTreeWrapperPass *DTWP =
631 getAnalysisIfAvailable<DominatorTreeWrapperPass>();
632 for (Instruction &I : instructions(F))
633 salvageKnowledge(&I, &AC, DTWP ? &DTWP->getDomTree() : nullptr);
634 return true;
635 }
636
637 void getAnalysisUsage(AnalysisUsage &AU) const override {
638 AU.addRequired<AssumptionCacheTracker>();
639
640 AU.setPreservesAll();
641 }
642};
643} // namespace
644
645char AssumeBuilderPassLegacyPass::ID = 0;
646
647INITIALIZE_PASS_BEGIN(AssumeBuilderPassLegacyPass, "assume-builder",static void *initializeAssumeBuilderPassLegacyPassPassOnce(PassRegistry
&Registry) {
648 "Assume Builder", false, false)static void *initializeAssumeBuilderPassLegacyPassPassOnce(PassRegistry
&Registry) {
649INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
650INITIALIZE_PASS_END(AssumeBuilderPassLegacyPass, "assume-builder",PassInfo *PI = new PassInfo( "Assume Builder", "assume-builder"
, &AssumeBuilderPassLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<AssumeBuilderPassLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeAssumeBuilderPassLegacyPassPassFlag; void
llvm::initializeAssumeBuilderPassLegacyPassPass(PassRegistry
&Registry) { llvm::call_once(InitializeAssumeBuilderPassLegacyPassPassFlag
, initializeAssumeBuilderPassLegacyPassPassOnce, std::ref(Registry
)); }
651 "Assume Builder", false, false)PassInfo *PI = new PassInfo( "Assume Builder", "assume-builder"
, &AssumeBuilderPassLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<AssumeBuilderPassLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeAssumeBuilderPassLegacyPassPassFlag; void
llvm::initializeAssumeBuilderPassLegacyPassPass(PassRegistry
&Registry) { llvm::call_once(InitializeAssumeBuilderPassLegacyPassPassFlag
, initializeAssumeBuilderPassLegacyPassPassOnce, std::ref(Registry
)); }
←

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support/Alignment.h

1//===-- llvm/Support/Alignment.h - Useful alignment functions ---*- 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 contains types to represent alignments.
10// They are instrumented to guarantee some invariants are preserved and prevent
11// invalid manipulations.
12//
13// - Align represents an alignment in bytes, it is always set and always a valid
14// power of two, its minimum value is 1 which means no alignment requirements.
15//
16// - MaybeAlign is an optional type, it may be undefined or set. When it's set
17// you can get the underlying Align type by using the getValue() method.
18//
19//===----------------------------------------------------------------------===//
20
21#ifndef LLVM_SUPPORT_ALIGNMENT_H_
22#define LLVM_SUPPORT_ALIGNMENT_H_
23
24#include "llvm/ADT/Optional.h"
25#include "llvm/Support/MathExtras.h"
26#include <cassert>
27#ifndef NDEBUG1
28#include <string>
29#endif // NDEBUG
30
31namespace llvm {
32
33#define ALIGN_CHECK_ISPOSITIVE(decl) \
34 assert(decl > 0 && (#decl " should be defined"))((void)0)
35
36/// This struct is a compact representation of a valid (non-zero power of two)
37/// alignment.
38/// It is suitable for use as static global constants.
39struct Align {
40private:
41 uint8_t ShiftValue = 0; /// The log2 of the required alignment.
42 /// ShiftValue is less than 64 by construction.
43
44 friend struct MaybeAlign;
45 friend unsigned Log2(Align);
46 friend bool operator==(Align Lhs, Align Rhs);
47 friend bool operator!=(Align Lhs, Align Rhs);
48 friend bool operator<=(Align Lhs, Align Rhs);
49 friend bool operator>=(Align Lhs, Align Rhs);
50 friend bool operator<(Align Lhs, Align Rhs);
51 friend bool operator>(Align Lhs, Align Rhs);
52 friend unsigned encode(struct MaybeAlign A);
53 friend struct MaybeAlign decodeMaybeAlign(unsigned Value);
54
55 /// A trivial type to allow construction of constexpr Align.
56 /// This is currently needed to workaround a bug in GCC 5.3 which prevents
57 /// definition of constexpr assign operators.
58 /// https://stackoverflow.com/questions/46756288/explicitly-defaulted-function-cannot-be-declared-as-constexpr-because-the-implic
59 /// FIXME: Remove this, make all assign operators constexpr and introduce user
60 /// defined literals when we don't have to support GCC 5.3 anymore.
61 /// https://llvm.org/docs/GettingStarted.html#getting-a-modern-host-c-toolchain
62 struct LogValue {
63 uint8_t Log;
64 };
65
66public:
67 /// Default is byte-aligned.
68 constexpr Align() = default;
69 /// Do not perform checks in case of copy/move construct/assign, because the
70 /// checks have been performed when building `Other`.
71 constexpr Align(const Align &Other) = default;
72 constexpr Align(Align &&Other) = default;
73 Align &operator=(const Align &Other) = default;
74 Align &operator=(Align &&Other) = default;
75
76 explicit Align(uint64_t Value) {
77 assert(Value > 0 && "Value must not be 0")((void)0);
78 assert(llvm::isPowerOf2_64(Value) && "Alignment is not a power of 2")((void)0);
79 ShiftValue = Log2_64(Value);
80 assert(ShiftValue < 64 && "Broken invariant")((void)0);
81 }
82
83 /// This is a hole in the type system and should not be abused.
84 /// Needed to interact with C for instance.
85 uint64_t value() const { return uint64_t(1) << ShiftValue; }
18
←
The result of the left shift is undefined due to shifting by '255', which is greater or equal to the width of type 'uint64_t'
86
87 /// Allow constructions of constexpr Align.
88 template <size_t kValue> constexpr static LogValue Constant() {
89 return LogValue{static_cast<uint8_t>(CTLog2<kValue>())};
90 }
91
92 /// Allow constructions of constexpr Align from types.
93 /// Compile time equivalent to Align(alignof(T)).
94 template <typename T> constexpr static LogValue Of() {
95 return Constant<std::alignment_of<T>::value>();
96 }
97
98 /// Constexpr constructor from LogValue type.
99 constexpr Align(LogValue CA) : ShiftValue(CA.Log) {}
100};
101
102/// Treats the value 0 as a 1, so Align is always at least 1.
103inline Align assumeAligned(uint64_t Value) {
104 return Value ? Align(Value) : Align();
105}
106
107/// This struct is a compact representation of a valid (power of two) or
108/// undefined (0) alignment.
109struct MaybeAlign : public llvm::Optional<Align> {
110private:
111 using UP = llvm::Optional<Align>;
112
113public:
114 /// Default is undefined.
115 MaybeAlign() = default;
116 /// Do not perform checks in case of copy/move construct/assign, because the
117 /// checks have been performed when building `Other`.
118 MaybeAlign(const MaybeAlign &Other) = default;
119 MaybeAlign &operator=(const MaybeAlign &Other) = default;
120 MaybeAlign(MaybeAlign &&Other) = default;
121 MaybeAlign &operator=(MaybeAlign &&Other) = default;
122
123 /// Use llvm::Optional<Align> constructor.
124 using UP::UP;
125
126 explicit MaybeAlign(uint64_t Value) {
127 assert((Value == 0 || llvm::isPowerOf2_64(Value)) &&((void)0)
128 "Alignment is neither 0 nor a power of 2")((void)0);
129 if (Value)
130 emplace(Value);
131 }
132
133 /// For convenience, returns a valid alignment or 1 if undefined.
134 Align valueOrOne() const { return hasValue() ? getValue() : Align(); }
13
←
'?' condition is true
→
14
←
The value 255 is assigned to 'Lhs.ShiftValue'
→
135};
136
137/// Checks that SizeInBytes is a multiple of the alignment.
138inline bool isAligned(Align Lhs, uint64_t SizeInBytes) {
139 return SizeInBytes % Lhs.value() == 0;
140}
141
142/// Checks that Addr is a multiple of the alignment.
143inline bool isAddrAligned(Align Lhs, const void *Addr) {
144 return isAligned(Lhs, reinterpret_cast<uintptr_t>(Addr));
145}
146
147/// Returns a multiple of A needed to store `Size` bytes.
148inline uint64_t alignTo(uint64_t Size, Align A) {
149 const uint64_t Value = A.value();
150 // The following line is equivalent to `(Size + Value - 1) / Value * Value`.
151
152 // The division followed by a multiplication can be thought of as a right
153 // shift followed by a left shift which zeros out the extra bits produced in
154 // the bump; `~(Value - 1)` is a mask where all those bits being zeroed out
155 // are just zero.
156
157 // Most compilers can generate this code but the pattern may be missed when
158 // multiple functions gets inlined.
159 return (Size + Value - 1) & ~(Value - 1U);
160}
161
162/// If non-zero \p Skew is specified, the return value will be a minimal integer
163/// that is greater than or equal to \p Size and equal to \p A * N + \p Skew for
164/// some integer N. If \p Skew is larger than \p A, its value is adjusted to '\p
165/// Skew mod \p A'.
166///
167/// Examples:
168/// \code
169/// alignTo(5, Align(8), 7) = 7
170/// alignTo(17, Align(8), 1) = 17
171/// alignTo(~0LL, Align(8), 3) = 3
172/// \endcode
173inline uint64_t alignTo(uint64_t Size, Align A, uint64_t Skew) {
174 const uint64_t Value = A.value();
175 Skew %= Value;
176 return ((Size + Value - 1 - Skew) & ~(Value - 1U)) + Skew;
177}
178
179/// Returns a multiple of A needed to store `Size` bytes.
180/// Returns `Size` if current alignment is undefined.
181inline uint64_t alignTo(uint64_t Size, MaybeAlign A) {
182 return A ? alignTo(Size, A.getValue()) : Size;
183}
184
185/// Aligns `Addr` to `Alignment` bytes, rounding up.
186inline uintptr_t alignAddr(const void *Addr, Align Alignment) {
187 uintptr_t ArithAddr = reinterpret_cast<uintptr_t>(Addr);
188 assert(static_cast<uintptr_t>(ArithAddr + Alignment.value() - 1) >=((void)0)
189 ArithAddr &&((void)0)
190 "Overflow")((void)0);
191 return alignTo(ArithAddr, Alignment);
192}
193
194/// Returns the offset to the next integer (mod 2**64) that is greater than
195/// or equal to \p Value and is a multiple of \p Align.
196inline uint64_t offsetToAlignment(uint64_t Value, Align Alignment) {
197 return alignTo(Value, Alignment) - Value;
198}
199
200/// Returns the necessary adjustment for aligning `Addr` to `Alignment`
201/// bytes, rounding up.
202inline uint64_t offsetToAlignedAddr(const void *Addr, Align Alignment) {
203 return offsetToAlignment(reinterpret_cast<uintptr_t>(Addr), Alignment);
204}
205
206/// Returns the log2 of the alignment.
207inline unsigned Log2(Align A) { return A.ShiftValue; }
208
209/// Returns the alignment that satisfies both alignments.
210/// Same semantic as MinAlign.
211inline Align commonAlignment(Align A, Align B) { return std::min(A, B); }
212
213/// Returns the alignment that satisfies both alignments.
214/// Same semantic as MinAlign.
215inline Align commonAlignment(Align A, uint64_t Offset) {
216 return Align(MinAlign(A.value(), Offset));
217}
218
219/// Returns the alignment that satisfies both alignments.
220/// Same semantic as MinAlign.
221inline MaybeAlign commonAlignment(MaybeAlign A, MaybeAlign B) {
222 return A && B ? commonAlignment(*A, *B) : A ? A : B;
223}
224
225/// Returns the alignment that satisfies both alignments.
226/// Same semantic as MinAlign.
227inline MaybeAlign commonAlignment(MaybeAlign A, uint64_t Offset) {
228 return MaybeAlign(MinAlign((*A).value(), Offset));
229}
230
231/// Returns a representation of the alignment that encodes undefined as 0.
232inline unsigned encode(MaybeAlign A) { return A ? A->ShiftValue + 1 : 0; }
233
234/// Dual operation of the encode function above.
235inline MaybeAlign decodeMaybeAlign(unsigned Value) {
236 if (Value == 0)
237 return MaybeAlign();
238 Align Out;
239 Out.ShiftValue = Value - 1;
240 return Out;
241}
242
243/// Returns a representation of the alignment, the encoded value is positive by
244/// definition.
245inline unsigned encode(Align A) { return encode(MaybeAlign(A)); }
246
247/// Comparisons between Align and scalars. Rhs must be positive.
248inline bool operator==(Align Lhs, uint64_t Rhs) {
249 ALIGN_CHECK_ISPOSITIVE(Rhs);
250 return Lhs.value() == Rhs;
251}
252inline bool operator!=(Align Lhs, uint64_t Rhs) {
253 ALIGN_CHECK_ISPOSITIVE(Rhs);
254 return Lhs.value() != Rhs;
255}
256inline bool operator<=(Align Lhs, uint64_t Rhs) {
257 ALIGN_CHECK_ISPOSITIVE(Rhs);
258 return Lhs.value() <= Rhs;
259}
260inline bool operator>=(Align Lhs, uint64_t Rhs) {
261 ALIGN_CHECK_ISPOSITIVE(Rhs);
262 return Lhs.value() >= Rhs;
263}
264inline bool operator<(Align Lhs, uint64_t Rhs) {
265 ALIGN_CHECK_ISPOSITIVE(Rhs);
266 return Lhs.value() < Rhs;
267}
268inline bool operator>(Align Lhs, uint64_t Rhs) {
269 ALIGN_CHECK_ISPOSITIVE(Rhs);
270 return Lhs.value() > Rhs;
17
←
Calling 'Align::value'
→
271}
272
273/// Comparisons between MaybeAlign and scalars.
274inline bool operator==(MaybeAlign Lhs, uint64_t Rhs) {
275 return Lhs ? (*Lhs).value() == Rhs : Rhs == 0;
276}
277inline bool operator!=(MaybeAlign Lhs, uint64_t Rhs) {
278 return Lhs ? (*Lhs).value() != Rhs : Rhs != 0;
279}
280
281/// Comparisons operators between Align.
282inline bool operator==(Align Lhs, Align Rhs) {
283 return Lhs.ShiftValue == Rhs.ShiftValue;
284}
285inline bool operator!=(Align Lhs, Align Rhs) {
286 return Lhs.ShiftValue != Rhs.ShiftValue;
287}
288inline bool operator<=(Align Lhs, Align Rhs) {
289 return Lhs.ShiftValue <= Rhs.ShiftValue;
290}
291inline bool operator>=(Align Lhs, Align Rhs) {
292 return Lhs.ShiftValue >= Rhs.ShiftValue;
293}
294inline bool operator<(Align Lhs, Align Rhs) {
295 return Lhs.ShiftValue < Rhs.ShiftValue;
296}
297inline bool operator>(Align Lhs, Align Rhs) {
298 return Lhs.ShiftValue > Rhs.ShiftValue;
299}
300
301// Don't allow relational comparisons with MaybeAlign.
302bool operator<=(Align Lhs, MaybeAlign Rhs) = delete;
303bool operator>=(Align Lhs, MaybeAlign Rhs) = delete;
304bool operator<(Align Lhs, MaybeAlign Rhs) = delete;
305bool operator>(Align Lhs, MaybeAlign Rhs) = delete;
306
307bool operator<=(MaybeAlign Lhs, Align Rhs) = delete;
308bool operator>=(MaybeAlign Lhs, Align Rhs) = delete;
309bool operator<(MaybeAlign Lhs, Align Rhs) = delete;
310bool operator>(MaybeAlign Lhs, Align Rhs) = delete;
311
312bool operator<=(MaybeAlign Lhs, MaybeAlign Rhs) = delete;
313bool operator>=(MaybeAlign Lhs, MaybeAlign Rhs) = delete;
314bool operator<(MaybeAlign Lhs, MaybeAlign Rhs) = delete;
315bool operator>(MaybeAlign Lhs, MaybeAlign Rhs) = delete;
316
317inline Align operator*(Align Lhs, uint64_t Rhs) {
318 assert(Rhs > 0 && "Rhs must be positive")((void)0);
319 return Align(Lhs.value() * Rhs);
320}
321
322inline MaybeAlign operator*(MaybeAlign Lhs, uint64_t Rhs) {
323 assert(Rhs > 0 && "Rhs must be positive")((void)0);
324 return Lhs ? Lhs.getValue() * Rhs : MaybeAlign();
325}
326
327inline Align operator/(Align Lhs, uint64_t Divisor) {
328 assert(llvm::isPowerOf2_64(Divisor) &&((void)0)
329 "Divisor must be positive and a power of 2")((void)0);
330 assert(Lhs != 1 && "Can't halve byte alignment")((void)0);
331 return Align(Lhs.value() / Divisor);
332}
333
334inline MaybeAlign operator/(MaybeAlign Lhs, uint64_t Divisor) {
335 assert(llvm::isPowerOf2_64(Divisor) &&((void)0)
336 "Divisor must be positive and a power of 2")((void)0);
337 return Lhs ? Lhs.getValue() / Divisor : MaybeAlign();
338}
339
340inline Align max(MaybeAlign Lhs, Align Rhs) {
341 return Lhs && *Lhs > Rhs ? *Lhs : Rhs;
342}
343
344inline Align max(Align Lhs, MaybeAlign Rhs) {
345 return Rhs && *Rhs > Lhs ? *Rhs : Lhs;
346}
347
348#ifndef NDEBUG1
349// For usage in LLVM_DEBUG macros.
350inline std::string DebugStr(const Align &A) {
351 return std::to_string(A.value());
352}
353// For usage in LLVM_DEBUG macros.
354inline std::string DebugStr(const MaybeAlign &MA) {
355 if (MA)
356 return std::to_string(MA->value());
357 return "None";
358}
359#endif // NDEBUG
360
361#undef ALIGN_CHECK_ISPOSITIVE
362
363} // namespace llvm
364
365#endif // LLVM_SUPPORT_ALIGNMENT_H_