Bug Summary

File:src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/GlobalMerge.cpp
Warning:line 631, column 29
Called C++ object pointer is null

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 GlobalMerge.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/CodeGen/GlobalMerge.cpp

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/GlobalMerge.cpp

1//===- GlobalMerge.cpp - Internal globals merging -------------------------===//
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 merges globals with internal linkage into one. This way all the
10// globals which were merged into a biggest one can be addressed using offsets
11// from the same base pointer (no need for separate base pointer for each of the
12// global). Such a transformation can significantly reduce the register pressure
13// when many globals are involved.
14//
15// For example, consider the code which touches several global variables at
16// once:
17//
18// static int foo[N], bar[N], baz[N];
19//
20// for (i = 0; i < N; ++i) {
21// foo[i] = bar[i] * baz[i];
22// }
23//
24// On ARM the addresses of 3 arrays should be kept in the registers, thus
25// this code has quite large register pressure (loop body):
26//
27// ldr r1, [r5], #4
28// ldr r2, [r6], #4
29// mul r1, r2, r1
30// str r1, [r0], #4
31//
32// Pass converts the code to something like:
33//
34// static struct {
35// int foo[N];
36// int bar[N];
37// int baz[N];
38// } merged;
39//
40// for (i = 0; i < N; ++i) {
41// merged.foo[i] = merged.bar[i] * merged.baz[i];
42// }
43//
44// and in ARM code this becomes:
45//
46// ldr r0, [r5, #40]
47// ldr r1, [r5, #80]
48// mul r0, r1, r0
49// str r0, [r5], #4
50//
51// note that we saved 2 registers here almostly "for free".
52//
53// However, merging globals can have tradeoffs:
54// - it confuses debuggers, tools, and users
55// - it makes linker optimizations less useful (order files, LOHs, ...)
56// - it forces usage of indexed addressing (which isn't necessarily "free")
57// - it can increase register pressure when the uses are disparate enough.
58//
59// We use heuristics to discover the best global grouping we can (cf cl::opts).
60//
61// ===---------------------------------------------------------------------===//
62
63#include "llvm/ADT/BitVector.h"
64#include "llvm/ADT/DenseMap.h"
65#include "llvm/ADT/SmallPtrSet.h"
66#include "llvm/ADT/SmallVector.h"
67#include "llvm/ADT/Statistic.h"
68#include "llvm/ADT/StringRef.h"
69#include "llvm/ADT/Triple.h"
70#include "llvm/ADT/Twine.h"
71#include "llvm/CodeGen/Passes.h"
72#include "llvm/IR/BasicBlock.h"
73#include "llvm/IR/Constants.h"
74#include "llvm/IR/DataLayout.h"
75#include "llvm/IR/DerivedTypes.h"
76#include "llvm/IR/Function.h"
77#include "llvm/IR/GlobalAlias.h"
78#include "llvm/IR/GlobalValue.h"
79#include "llvm/IR/GlobalVariable.h"
80#include "llvm/IR/Instruction.h"
81#include "llvm/IR/Module.h"
82#include "llvm/IR/Type.h"
83#include "llvm/IR/Use.h"
84#include "llvm/IR/User.h"
85#include "llvm/InitializePasses.h"
86#include "llvm/MC/SectionKind.h"
87#include "llvm/Pass.h"
88#include "llvm/Support/Casting.h"
89#include "llvm/Support/CommandLine.h"
90#include "llvm/Support/Debug.h"
91#include "llvm/Support/raw_ostream.h"
92#include "llvm/Target/TargetLoweringObjectFile.h"
93#include "llvm/Target/TargetMachine.h"
94#include <algorithm>
95#include <cassert>
96#include <cstddef>
97#include <cstdint>
98#include <string>
99#include <vector>
100
101using namespace llvm;
102
103#define DEBUG_TYPE"global-merge" "global-merge"
104
105// FIXME: This is only useful as a last-resort way to disable the pass.
106static cl::opt<bool>
107EnableGlobalMerge("enable-global-merge", cl::Hidden,
108 cl::desc("Enable the global merge pass"),
109 cl::init(true));
110
111static cl::opt<unsigned>
112GlobalMergeMaxOffset("global-merge-max-offset", cl::Hidden,
113 cl::desc("Set maximum offset for global merge pass"),
114 cl::init(0));
115
116static cl::opt<bool> GlobalMergeGroupByUse(
117 "global-merge-group-by-use", cl::Hidden,
118 cl::desc("Improve global merge pass to look at uses"), cl::init(true));
119
120static cl::opt<bool> GlobalMergeIgnoreSingleUse(
121 "global-merge-ignore-single-use", cl::Hidden,
122 cl::desc("Improve global merge pass to ignore globals only used alone"),
123 cl::init(true));
124
125static cl::opt<bool>
126EnableGlobalMergeOnConst("global-merge-on-const", cl::Hidden,
127 cl::desc("Enable global merge pass on constants"),
128 cl::init(false));
129
130// FIXME: this could be a transitional option, and we probably need to remove
131// it if only we are sure this optimization could always benefit all targets.
132static cl::opt<cl::boolOrDefault>
133EnableGlobalMergeOnExternal("global-merge-on-external", cl::Hidden,
134 cl::desc("Enable global merge pass on external linkage"));
135
136STATISTIC(NumMerged, "Number of globals merged")static llvm::Statistic NumMerged = {"global-merge", "NumMerged"
, "Number of globals merged"}
;
137
138namespace {
139
140 class GlobalMerge : public FunctionPass {
141 const TargetMachine *TM = nullptr;
142
143 // FIXME: Infer the maximum possible offset depending on the actual users
144 // (these max offsets are different for the users inside Thumb or ARM
145 // functions), see the code that passes in the offset in the ARM backend
146 // for more information.
147 unsigned MaxOffset;
148
149 /// Whether we should try to optimize for size only.
150 /// Currently, this applies a dead simple heuristic: only consider globals
151 /// used in minsize functions for merging.
152 /// FIXME: This could learn about optsize, and be used in the cost model.
153 bool OnlyOptimizeForSize = false;
154
155 /// Whether we should merge global variables that have external linkage.
156 bool MergeExternalGlobals = false;
157
158 bool IsMachO;
159
160 bool doMerge(SmallVectorImpl<GlobalVariable*> &Globals,
161 Module &M, bool isConst, unsigned AddrSpace) const;
162
163 /// Merge everything in \p Globals for which the corresponding bit
164 /// in \p GlobalSet is set.
165 bool doMerge(const SmallVectorImpl<GlobalVariable *> &Globals,
166 const BitVector &GlobalSet, Module &M, bool isConst,
167 unsigned AddrSpace) const;
168
169 /// Check if the given variable has been identified as must keep
170 /// \pre setMustKeepGlobalVariables must have been called on the Module that
171 /// contains GV
172 bool isMustKeepGlobalVariable(const GlobalVariable *GV) const {
173 return MustKeepGlobalVariables.count(GV);
174 }
175
176 /// Collect every variables marked as "used" or used in a landing pad
177 /// instruction for this Module.
178 void setMustKeepGlobalVariables(Module &M);
179
180 /// Collect every variables marked as "used"
181 void collectUsedGlobalVariables(Module &M, StringRef Name);
182
183 /// Keep track of the GlobalVariable that must not be merged away
184 SmallPtrSet<const GlobalVariable *, 16> MustKeepGlobalVariables;
185
186 public:
187 static char ID; // Pass identification, replacement for typeid.
188
189 explicit GlobalMerge()
190 : FunctionPass(ID), MaxOffset(GlobalMergeMaxOffset) {
191 initializeGlobalMergePass(*PassRegistry::getPassRegistry());
192 }
193
194 explicit GlobalMerge(const TargetMachine *TM, unsigned MaximalOffset,
195 bool OnlyOptimizeForSize, bool MergeExternalGlobals)
196 : FunctionPass(ID), TM(TM), MaxOffset(MaximalOffset),
197 OnlyOptimizeForSize(OnlyOptimizeForSize),
198 MergeExternalGlobals(MergeExternalGlobals) {
199 initializeGlobalMergePass(*PassRegistry::getPassRegistry());
200 }
201
202 bool doInitialization(Module &M) override;
203 bool runOnFunction(Function &F) override;
204 bool doFinalization(Module &M) override;
205
206 StringRef getPassName() const override { return "Merge internal globals"; }
207
208 void getAnalysisUsage(AnalysisUsage &AU) const override {
209 AU.setPreservesCFG();
210 FunctionPass::getAnalysisUsage(AU);
211 }
212 };
213
214} // end anonymous namespace
215
216char GlobalMerge::ID = 0;
217
218INITIALIZE_PASS(GlobalMerge, DEBUG_TYPE, "Merge global variables", false, false)static void *initializeGlobalMergePassOnce(PassRegistry &
Registry) { PassInfo *PI = new PassInfo( "Merge global variables"
, "global-merge", &GlobalMerge::ID, PassInfo::NormalCtor_t
(callDefaultCtor<GlobalMerge>), false, false); Registry
.registerPass(*PI, true); return PI; } static llvm::once_flag
InitializeGlobalMergePassFlag; void llvm::initializeGlobalMergePass
(PassRegistry &Registry) { llvm::call_once(InitializeGlobalMergePassFlag
, initializeGlobalMergePassOnce, std::ref(Registry)); }
219
220bool GlobalMerge::doMerge(SmallVectorImpl<GlobalVariable*> &Globals,
221 Module &M, bool isConst, unsigned AddrSpace) const {
222 auto &DL = M.getDataLayout();
223 // FIXME: Find better heuristics
224 llvm::stable_sort(
225 Globals, [&DL](const GlobalVariable *GV1, const GlobalVariable *GV2) {
226 // We don't support scalable global variables.
227 return DL.getTypeAllocSize(GV1->getValueType()).getFixedSize() <
228 DL.getTypeAllocSize(GV2->getValueType()).getFixedSize();
229 });
230
231 // If we want to just blindly group all globals together, do so.
232 if (!GlobalMergeGroupByUse) {
233 BitVector AllGlobals(Globals.size());
234 AllGlobals.set();
235 return doMerge(Globals, AllGlobals, M, isConst, AddrSpace);
236 }
237
238 // If we want to be smarter, look at all uses of each global, to try to
239 // discover all sets of globals used together, and how many times each of
240 // these sets occurred.
241 //
242 // Keep this reasonably efficient, by having an append-only list of all sets
243 // discovered so far (UsedGlobalSet), and mapping each "together-ness" unit of
244 // code (currently, a Function) to the set of globals seen so far that are
245 // used together in that unit (GlobalUsesByFunction).
246 //
247 // When we look at the Nth global, we know that any new set is either:
248 // - the singleton set {N}, containing this global only, or
249 // - the union of {N} and a previously-discovered set, containing some
250 // combination of the previous N-1 globals.
251 // Using that knowledge, when looking at the Nth global, we can keep:
252 // - a reference to the singleton set {N} (CurGVOnlySetIdx)
253 // - a list mapping each previous set to its union with {N} (EncounteredUGS),
254 // if it actually occurs.
255
256 // We keep track of the sets of globals used together "close enough".
257 struct UsedGlobalSet {
258 BitVector Globals;
259 unsigned UsageCount = 1;
260
261 UsedGlobalSet(size_t Size) : Globals(Size) {}
262 };
263
264 // Each set is unique in UsedGlobalSets.
265 std::vector<UsedGlobalSet> UsedGlobalSets;
266
267 // Avoid repeating the create-global-set pattern.
268 auto CreateGlobalSet = [&]() -> UsedGlobalSet & {
269 UsedGlobalSets.emplace_back(Globals.size());
270 return UsedGlobalSets.back();
271 };
272
273 // The first set is the empty set.
274 CreateGlobalSet().UsageCount = 0;
275
276 // We define "close enough" to be "in the same function".
277 // FIXME: Grouping uses by function is way too aggressive, so we should have
278 // a better metric for distance between uses.
279 // The obvious alternative would be to group by BasicBlock, but that's in
280 // turn too conservative..
281 // Anything in between wouldn't be trivial to compute, so just stick with
282 // per-function grouping.
283
284 // The value type is an index into UsedGlobalSets.
285 // The default (0) conveniently points to the empty set.
286 DenseMap<Function *, size_t /*UsedGlobalSetIdx*/> GlobalUsesByFunction;
287
288 // Now, look at each merge-eligible global in turn.
289
290 // Keep track of the sets we already encountered to which we added the
291 // current global.
292 // Each element matches the same-index element in UsedGlobalSets.
293 // This lets us efficiently tell whether a set has already been expanded to
294 // include the current global.
295 std::vector<size_t> EncounteredUGS;
296
297 for (size_t GI = 0, GE = Globals.size(); GI != GE; ++GI) {
298 GlobalVariable *GV = Globals[GI];
299
300 // Reset the encountered sets for this global...
301 std::fill(EncounteredUGS.begin(), EncounteredUGS.end(), 0);
302 // ...and grow it in case we created new sets for the previous global.
303 EncounteredUGS.resize(UsedGlobalSets.size());
304
305 // We might need to create a set that only consists of the current global.
306 // Keep track of its index into UsedGlobalSets.
307 size_t CurGVOnlySetIdx = 0;
308
309 // For each global, look at all its Uses.
310 for (auto &U : GV->uses()) {
311 // This Use might be a ConstantExpr. We're interested in Instruction
312 // users, so look through ConstantExpr...
313 Use *UI, *UE;
314 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U.getUser())) {
315 if (CE->use_empty())
316 continue;
317 UI = &*CE->use_begin();
318 UE = nullptr;
319 } else if (isa<Instruction>(U.getUser())) {
320 UI = &U;
321 UE = UI->getNext();
322 } else {
323 continue;
324 }
325
326 // ...to iterate on all the instruction users of the global.
327 // Note that we iterate on Uses and not on Users to be able to getNext().
328 for (; UI != UE; UI = UI->getNext()) {
329 Instruction *I = dyn_cast<Instruction>(UI->getUser());
330 if (!I)
331 continue;
332
333 Function *ParentFn = I->getParent()->getParent();
334
335 // If we're only optimizing for size, ignore non-minsize functions.
336 if (OnlyOptimizeForSize && !ParentFn->hasMinSize())
337 continue;
338
339 size_t UGSIdx = GlobalUsesByFunction[ParentFn];
340
341 // If this is the first global the basic block uses, map it to the set
342 // consisting of this global only.
343 if (!UGSIdx) {
344 // If that set doesn't exist yet, create it.
345 if (!CurGVOnlySetIdx) {
346 CurGVOnlySetIdx = UsedGlobalSets.size();
347 CreateGlobalSet().Globals.set(GI);
348 } else {
349 ++UsedGlobalSets[CurGVOnlySetIdx].UsageCount;
350 }
351
352 GlobalUsesByFunction[ParentFn] = CurGVOnlySetIdx;
353 continue;
354 }
355
356 // If we already encountered this BB, just increment the counter.
357 if (UsedGlobalSets[UGSIdx].Globals.test(GI)) {
358 ++UsedGlobalSets[UGSIdx].UsageCount;
359 continue;
360 }
361
362 // If not, the previous set wasn't actually used in this function.
363 --UsedGlobalSets[UGSIdx].UsageCount;
364
365 // If we already expanded the previous set to include this global, just
366 // reuse that expanded set.
367 if (size_t ExpandedIdx = EncounteredUGS[UGSIdx]) {
368 ++UsedGlobalSets[ExpandedIdx].UsageCount;
369 GlobalUsesByFunction[ParentFn] = ExpandedIdx;
370 continue;
371 }
372
373 // If not, create a new set consisting of the union of the previous set
374 // and this global. Mark it as encountered, so we can reuse it later.
375 GlobalUsesByFunction[ParentFn] = EncounteredUGS[UGSIdx] =
376 UsedGlobalSets.size();
377
378 UsedGlobalSet &NewUGS = CreateGlobalSet();
379 NewUGS.Globals.set(GI);
380 NewUGS.Globals |= UsedGlobalSets[UGSIdx].Globals;
381 }
382 }
383 }
384
385 // Now we found a bunch of sets of globals used together. We accumulated
386 // the number of times we encountered the sets (i.e., the number of blocks
387 // that use that exact set of globals).
388 //
389 // Multiply that by the size of the set to give us a crude profitability
390 // metric.
391 llvm::stable_sort(UsedGlobalSets,
392 [](const UsedGlobalSet &UGS1, const UsedGlobalSet &UGS2) {
393 return UGS1.Globals.count() * UGS1.UsageCount <
394 UGS2.Globals.count() * UGS2.UsageCount;
395 });
396
397 // We can choose to merge all globals together, but ignore globals never used
398 // with another global. This catches the obviously non-profitable cases of
399 // having a single global, but is aggressive enough for any other case.
400 if (GlobalMergeIgnoreSingleUse) {
401 BitVector AllGlobals(Globals.size());
402 for (size_t i = 0, e = UsedGlobalSets.size(); i != e; ++i) {
403 const UsedGlobalSet &UGS = UsedGlobalSets[e - i - 1];
404 if (UGS.UsageCount == 0)
405 continue;
406 if (UGS.Globals.count() > 1)
407 AllGlobals |= UGS.Globals;
408 }
409 return doMerge(Globals, AllGlobals, M, isConst, AddrSpace);
410 }
411
412 // Starting from the sets with the best (=biggest) profitability, find a
413 // good combination.
414 // The ideal (and expensive) solution can only be found by trying all
415 // combinations, looking for the one with the best profitability.
416 // Don't be smart about it, and just pick the first compatible combination,
417 // starting with the sets with the best profitability.
418 BitVector PickedGlobals(Globals.size());
419 bool Changed = false;
420
421 for (size_t i = 0, e = UsedGlobalSets.size(); i != e; ++i) {
422 const UsedGlobalSet &UGS = UsedGlobalSets[e - i - 1];
423 if (UGS.UsageCount == 0)
424 continue;
425 if (PickedGlobals.anyCommon(UGS.Globals))
426 continue;
427 PickedGlobals |= UGS.Globals;
428 // If the set only contains one global, there's no point in merging.
429 // Ignore the global for inclusion in other sets though, so keep it in
430 // PickedGlobals.
431 if (UGS.Globals.count() < 2)
432 continue;
433 Changed |= doMerge(Globals, UGS.Globals, M, isConst, AddrSpace);
434 }
435
436 return Changed;
437}
438
439bool GlobalMerge::doMerge(const SmallVectorImpl<GlobalVariable *> &Globals,
440 const BitVector &GlobalSet, Module &M, bool isConst,
441 unsigned AddrSpace) const {
442 assert(Globals.size() > 1)((void)0);
443
444 Type *Int32Ty = Type::getInt32Ty(M.getContext());
445 Type *Int8Ty = Type::getInt8Ty(M.getContext());
446 auto &DL = M.getDataLayout();
447
448 LLVM_DEBUG(dbgs() << " Trying to merge set, starts with #"do { } while (false)
449 << GlobalSet.find_first() << "\n")do { } while (false);
450
451 bool Changed = false;
452 ssize_t i = GlobalSet.find_first();
453 while (i != -1) {
454 ssize_t j = 0;
455 uint64_t MergedSize = 0;
456 std::vector<Type*> Tys;
457 std::vector<Constant*> Inits;
458 std::vector<unsigned> StructIdxs;
459
460 bool HasExternal = false;
461 StringRef FirstExternalName;
462 Align MaxAlign;
463 unsigned CurIdx = 0;
464 for (j = i; j != -1; j = GlobalSet.find_next(j)) {
465 Type *Ty = Globals[j]->getValueType();
466
467 // Make sure we use the same alignment AsmPrinter would use.
468 Align Alignment = DL.getPreferredAlign(Globals[j]);
469 unsigned Padding = alignTo(MergedSize, Alignment) - MergedSize;
470 MergedSize += Padding;
471 MergedSize += DL.getTypeAllocSize(Ty);
472 if (MergedSize > MaxOffset) {
473 break;
474 }
475 if (Padding) {
476 Tys.push_back(ArrayType::get(Int8Ty, Padding));
477 Inits.push_back(ConstantAggregateZero::get(Tys.back()));
478 ++CurIdx;
479 }
480 Tys.push_back(Ty);
481 Inits.push_back(Globals[j]->getInitializer());
482 StructIdxs.push_back(CurIdx++);
483
484 MaxAlign = std::max(MaxAlign, Alignment);
485
486 if (Globals[j]->hasExternalLinkage() && !HasExternal) {
487 HasExternal = true;
488 FirstExternalName = Globals[j]->getName();
489 }
490 }
491
492 // Exit early if there is only one global to merge.
493 if (Tys.size() < 2) {
494 i = j;
495 continue;
496 }
497
498 // If merged variables doesn't have external linkage, we needn't to expose
499 // the symbol after merging.
500 GlobalValue::LinkageTypes Linkage = HasExternal
501 ? GlobalValue::ExternalLinkage
502 : GlobalValue::InternalLinkage;
503 // Use a packed struct so we can control alignment.
504 StructType *MergedTy = StructType::get(M.getContext(), Tys, true);
505 Constant *MergedInit = ConstantStruct::get(MergedTy, Inits);
506
507 // On Darwin external linkage needs to be preserved, otherwise
508 // dsymutil cannot preserve the debug info for the merged
509 // variables. If they have external linkage, use the symbol name
510 // of the first variable merged as the suffix of global symbol
511 // name. This avoids a link-time naming conflict for the
512 // _MergedGlobals symbols.
513 Twine MergedName =
514 (IsMachO && HasExternal)
515 ? "_MergedGlobals_" + FirstExternalName
516 : "_MergedGlobals";
517 auto MergedLinkage = IsMachO ? Linkage : GlobalValue::PrivateLinkage;
518 auto *MergedGV = new GlobalVariable(
519 M, MergedTy, isConst, MergedLinkage, MergedInit, MergedName, nullptr,
520 GlobalVariable::NotThreadLocal, AddrSpace);
521
522 MergedGV->setAlignment(MaxAlign);
523 MergedGV->setSection(Globals[i]->getSection());
524
525 const StructLayout *MergedLayout = DL.getStructLayout(MergedTy);
526 for (ssize_t k = i, idx = 0; k != j; k = GlobalSet.find_next(k), ++idx) {
527 GlobalValue::LinkageTypes Linkage = Globals[k]->getLinkage();
528 std::string Name(Globals[k]->getName());
529 GlobalValue::VisibilityTypes Visibility = Globals[k]->getVisibility();
530 GlobalValue::DLLStorageClassTypes DLLStorage =
531 Globals[k]->getDLLStorageClass();
532
533 // Copy metadata while adjusting any debug info metadata by the original
534 // global's offset within the merged global.
535 MergedGV->copyMetadata(Globals[k],
536 MergedLayout->getElementOffset(StructIdxs[idx]));
537
538 Constant *Idx[2] = {
539 ConstantInt::get(Int32Ty, 0),
540 ConstantInt::get(Int32Ty, StructIdxs[idx]),
541 };
542 Constant *GEP =
543 ConstantExpr::getInBoundsGetElementPtr(MergedTy, MergedGV, Idx);
544 Globals[k]->replaceAllUsesWith(GEP);
545 Globals[k]->eraseFromParent();
546
547 // When the linkage is not internal we must emit an alias for the original
548 // variable name as it may be accessed from another object. On non-Mach-O
549 // we can also emit an alias for internal linkage as it's safe to do so.
550 // It's not safe on Mach-O as the alias (and thus the portion of the
551 // MergedGlobals variable) may be dead stripped at link time.
552 if (Linkage != GlobalValue::InternalLinkage || !IsMachO) {
553 GlobalAlias *GA = GlobalAlias::create(Tys[StructIdxs[idx]], AddrSpace,
554 Linkage, Name, GEP, &M);
555 GA->setVisibility(Visibility);
556 GA->setDLLStorageClass(DLLStorage);
557 }
558
559 NumMerged++;
560 }
561 Changed = true;
562 i = j;
563 }
564
565 return Changed;
566}
567
568void GlobalMerge::collectUsedGlobalVariables(Module &M, StringRef Name) {
569 // Extract global variables from llvm.used array
570 const GlobalVariable *GV = M.getGlobalVariable(Name);
571 if (!GV || !GV->hasInitializer()) return;
572
573 // Should be an array of 'i8*'.
574 const ConstantArray *InitList = cast<ConstantArray>(GV->getInitializer());
575
576 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
577 if (const GlobalVariable *G =
578 dyn_cast<GlobalVariable>(InitList->getOperand(i)->stripPointerCasts()))
579 MustKeepGlobalVariables.insert(G);
580}
581
582void GlobalMerge::setMustKeepGlobalVariables(Module &M) {
583 collectUsedGlobalVariables(M, "llvm.used");
584 collectUsedGlobalVariables(M, "llvm.compiler.used");
585
586 for (Function &F : M) {
587 for (BasicBlock &BB : F) {
588 Instruction *Pad = BB.getFirstNonPHI();
589 if (!Pad->isEHPad())
590 continue;
591
592 // Keep globals used by landingpads and catchpads.
593 for (const Use &U : Pad->operands()) {
594 if (const GlobalVariable *GV =
595 dyn_cast<GlobalVariable>(U->stripPointerCasts()))
596 MustKeepGlobalVariables.insert(GV);
597 }
598 }
599 }
600}
601
602bool GlobalMerge::doInitialization(Module &M) {
603 if (!EnableGlobalMerge)
1
Assuming the condition is false
2
Taking false branch
604 return false;
605
606 IsMachO = Triple(M.getTargetTriple()).isOSBinFormatMachO();
607
608 auto &DL = M.getDataLayout();
609 DenseMap<std::pair<unsigned, StringRef>, SmallVector<GlobalVariable *, 16>>
610 Globals, ConstGlobals, BSSGlobals;
611 bool Changed = false;
612 setMustKeepGlobalVariables(M);
613
614 // Grab all non-const globals.
615 for (auto &GV : M.globals()) {
616 // Merge is safe for "normal" internal or external globals only
617 if (GV.isDeclaration() || GV.isThreadLocal() || GV.hasImplicitSection())
3
Assuming the condition is false
4
Calling 'GlobalValue::isThreadLocal'
7
Returning from 'GlobalValue::isThreadLocal'
8
Calling 'GlobalVariable::hasImplicitSection'
13
Returning from 'GlobalVariable::hasImplicitSection'
14
Assuming the condition is false
15
Taking false branch
618 continue;
619
620 // It's not safe to merge globals that may be preempted
621 if (TM && !TM->shouldAssumeDSOLocal(M, &GV))
16
Assuming field 'TM' is null
622 continue;
623
624 if (!(MergeExternalGlobals && GV.hasExternalLinkage()) &&
17
Assuming field 'MergeExternalGlobals' is false
25
Taking false branch
625 !GV.hasInternalLinkage())
18
Calling 'GlobalValue::hasInternalLinkage'
24
Returning from 'GlobalValue::hasInternalLinkage'
626 continue;
627
628 PointerType *PT = dyn_cast<PointerType>(GV.getType());
26
Assuming the object is not a 'PointerType'
27
'PT' initialized to a null pointer value
629 assert(PT && "Global variable is not a pointer!")((void)0);
630
631 unsigned AddressSpace = PT->getAddressSpace();
28
Called C++ object pointer is null
632 StringRef Section = GV.getSection();
633
634 // Ignore all 'special' globals.
635 if (GV.getName().startswith("llvm.") ||
636 GV.getName().startswith(".llvm."))
637 continue;
638
639 // Ignore all "required" globals:
640 if (isMustKeepGlobalVariable(&GV))
641 continue;
642
643 Type *Ty = GV.getValueType();
644 if (DL.getTypeAllocSize(Ty) < MaxOffset) {
645 if (TM &&
646 TargetLoweringObjectFile::getKindForGlobal(&GV, *TM).isBSS())
647 BSSGlobals[{AddressSpace, Section}].push_back(&GV);
648 else if (GV.isConstant())
649 ConstGlobals[{AddressSpace, Section}].push_back(&GV);
650 else
651 Globals[{AddressSpace, Section}].push_back(&GV);
652 }
653 }
654
655 for (auto &P : Globals)
656 if (P.second.size() > 1)
657 Changed |= doMerge(P.second, M, false, P.first.first);
658
659 for (auto &P : BSSGlobals)
660 if (P.second.size() > 1)
661 Changed |= doMerge(P.second, M, false, P.first.first);
662
663 if (EnableGlobalMergeOnConst)
664 for (auto &P : ConstGlobals)
665 if (P.second.size() > 1)
666 Changed |= doMerge(P.second, M, true, P.first.first);
667
668 return Changed;
669}
670
671bool GlobalMerge::runOnFunction(Function &F) {
672 return false;
673}
674
675bool GlobalMerge::doFinalization(Module &M) {
676 MustKeepGlobalVariables.clear();
677 return false;
678}
679
680Pass *llvm::createGlobalMergePass(const TargetMachine *TM, unsigned Offset,
681 bool OnlyOptimizeForSize,
682 bool MergeExternalByDefault) {
683 bool MergeExternal = (EnableGlobalMergeOnExternal == cl::BOU_UNSET) ?
684 MergeExternalByDefault : (EnableGlobalMergeOnExternal == cl::BOU_TRUE);
685 return new GlobalMerge(TM, Offset, OnlyOptimizeForSize, MergeExternal);
686}

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IR/GlobalValue.h

1//===-- llvm/GlobalValue.h - Class to represent a global value --*- 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 is a common base class of all globally definable objects. As such,
10// it is subclassed by GlobalVariable, GlobalAlias and by Function. This is
11// used because you can do certain things with these global objects that you
12// can't do to anything else. For example, use the address of one as a
13// constant.
14//
15//===----------------------------------------------------------------------===//
16
17#ifndef LLVM_IR_GLOBALVALUE_H
18#define LLVM_IR_GLOBALVALUE_H
19
20#include "llvm/ADT/StringRef.h"
21#include "llvm/ADT/Twine.h"
22#include "llvm/IR/Constant.h"
23#include "llvm/IR/DerivedTypes.h"
24#include "llvm/IR/Value.h"
25#include "llvm/Support/Casting.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/MD5.h"
28#include <cassert>
29#include <cstdint>
30#include <string>
31
32namespace llvm {
33
34class Comdat;
35class ConstantRange;
36class Error;
37class GlobalObject;
38class Module;
39
40namespace Intrinsic {
41typedef unsigned ID;
42} // end namespace Intrinsic
43
44class GlobalValue : public Constant {
45public:
46 /// An enumeration for the kinds of linkage for global values.
47 enum LinkageTypes {
48 ExternalLinkage = 0,///< Externally visible function
49 AvailableExternallyLinkage, ///< Available for inspection, not emission.
50 LinkOnceAnyLinkage, ///< Keep one copy of function when linking (inline)
51 LinkOnceODRLinkage, ///< Same, but only replaced by something equivalent.
52 WeakAnyLinkage, ///< Keep one copy of named function when linking (weak)
53 WeakODRLinkage, ///< Same, but only replaced by something equivalent.
54 AppendingLinkage, ///< Special purpose, only applies to global arrays
55 InternalLinkage, ///< Rename collisions when linking (static functions).
56 PrivateLinkage, ///< Like Internal, but omit from symbol table.
57 ExternalWeakLinkage,///< ExternalWeak linkage description.
58 CommonLinkage ///< Tentative definitions.
59 };
60
61 /// An enumeration for the kinds of visibility of global values.
62 enum VisibilityTypes {
63 DefaultVisibility = 0, ///< The GV is visible
64 HiddenVisibility, ///< The GV is hidden
65 ProtectedVisibility ///< The GV is protected
66 };
67
68 /// Storage classes of global values for PE targets.
69 enum DLLStorageClassTypes {
70 DefaultStorageClass = 0,
71 DLLImportStorageClass = 1, ///< Function to be imported from DLL
72 DLLExportStorageClass = 2 ///< Function to be accessible from DLL.
73 };
74
75protected:
76 GlobalValue(Type *Ty, ValueTy VTy, Use *Ops, unsigned NumOps,
77 LinkageTypes Linkage, const Twine &Name, unsigned AddressSpace)
78 : Constant(PointerType::get(Ty, AddressSpace), VTy, Ops, NumOps),
79 ValueType(Ty), Visibility(DefaultVisibility),
80 UnnamedAddrVal(unsigned(UnnamedAddr::None)),
81 DllStorageClass(DefaultStorageClass), ThreadLocal(NotThreadLocal),
82 HasLLVMReservedName(false), IsDSOLocal(false), HasPartition(false),
83 IntID((Intrinsic::ID)0U), Parent(nullptr) {
84 setLinkage(Linkage);
85 setName(Name);
86 }
87
88 Type *ValueType;
89
90 static const unsigned GlobalValueSubClassDataBits = 16;
91
92 // All bitfields use unsigned as the underlying type so that MSVC will pack
93 // them.
94 unsigned Linkage : 4; // The linkage of this global
95 unsigned Visibility : 2; // The visibility style of this global
96 unsigned UnnamedAddrVal : 2; // This value's address is not significant
97 unsigned DllStorageClass : 2; // DLL storage class
98
99 unsigned ThreadLocal : 3; // Is this symbol "Thread Local", if so, what is
100 // the desired model?
101
102 /// True if the function's name starts with "llvm.". This corresponds to the
103 /// value of Function::isIntrinsic(), which may be true even if
104 /// Function::intrinsicID() returns Intrinsic::not_intrinsic.
105 unsigned HasLLVMReservedName : 1;
106
107 /// If true then there is a definition within the same linkage unit and that
108 /// definition cannot be runtime preempted.
109 unsigned IsDSOLocal : 1;
110
111 /// True if this symbol has a partition name assigned (see
112 /// https://lld.llvm.org/Partitions.html).
113 unsigned HasPartition : 1;
114
115private:
116 // Give subclasses access to what otherwise would be wasted padding.
117 // (16 + 4 + 2 + 2 + 2 + 3 + 1 + 1 + 1) == 32.
118 unsigned SubClassData : GlobalValueSubClassDataBits;
119
120 friend class Constant;
121
122 void destroyConstantImpl();
123 Value *handleOperandChangeImpl(Value *From, Value *To);
124
125 /// Returns true if the definition of this global may be replaced by a
126 /// differently optimized variant of the same source level function at link
127 /// time.
128 bool mayBeDerefined() const {
129 switch (getLinkage()) {
130 case WeakODRLinkage:
131 case LinkOnceODRLinkage:
132 case AvailableExternallyLinkage:
133 return true;
134
135 case WeakAnyLinkage:
136 case LinkOnceAnyLinkage:
137 case CommonLinkage:
138 case ExternalWeakLinkage:
139 case ExternalLinkage:
140 case AppendingLinkage:
141 case InternalLinkage:
142 case PrivateLinkage:
143 return isInterposable();
144 }
145
146 llvm_unreachable("Fully covered switch above!")__builtin_unreachable();
147 }
148
149protected:
150 /// The intrinsic ID for this subclass (which must be a Function).
151 ///
152 /// This member is defined by this class, but not used for anything.
153 /// Subclasses can use it to store their intrinsic ID, if they have one.
154 ///
155 /// This is stored here to save space in Function on 64-bit hosts.
156 Intrinsic::ID IntID;
157
158 unsigned getGlobalValueSubClassData() const {
159 return SubClassData;
160 }
161 void setGlobalValueSubClassData(unsigned V) {
162 assert(V < (1 << GlobalValueSubClassDataBits) && "It will not fit")((void)0);
163 SubClassData = V;
164 }
165
166 Module *Parent; // The containing module.
167
168 // Used by SymbolTableListTraits.
169 void setParent(Module *parent) {
170 Parent = parent;
171 }
172
173 ~GlobalValue() {
174 removeDeadConstantUsers(); // remove any dead constants using this.
175 }
176
177public:
178 enum ThreadLocalMode {
179 NotThreadLocal = 0,
180 GeneralDynamicTLSModel,
181 LocalDynamicTLSModel,
182 InitialExecTLSModel,
183 LocalExecTLSModel
184 };
185
186 GlobalValue(const GlobalValue &) = delete;
187
188 unsigned getAddressSpace() const;
189
190 enum class UnnamedAddr {
191 None,
192 Local,
193 Global,
194 };
195
196 bool hasGlobalUnnamedAddr() const {
197 return getUnnamedAddr() == UnnamedAddr::Global;
198 }
199
200 /// Returns true if this value's address is not significant in this module.
201 /// This attribute is intended to be used only by the code generator and LTO
202 /// to allow the linker to decide whether the global needs to be in the symbol
203 /// table. It should probably not be used in optimizations, as the value may
204 /// have uses outside the module; use hasGlobalUnnamedAddr() instead.
205 bool hasAtLeastLocalUnnamedAddr() const {
206 return getUnnamedAddr() != UnnamedAddr::None;
207 }
208
209 UnnamedAddr getUnnamedAddr() const {
210 return UnnamedAddr(UnnamedAddrVal);
211 }
212 void setUnnamedAddr(UnnamedAddr Val) { UnnamedAddrVal = unsigned(Val); }
213
214 static UnnamedAddr getMinUnnamedAddr(UnnamedAddr A, UnnamedAddr B) {
215 if (A == UnnamedAddr::None || B == UnnamedAddr::None)
216 return UnnamedAddr::None;
217 if (A == UnnamedAddr::Local || B == UnnamedAddr::Local)
218 return UnnamedAddr::Local;
219 return UnnamedAddr::Global;
220 }
221
222 bool hasComdat() const { return getComdat() != nullptr; }
223 const Comdat *getComdat() const;
224 Comdat *getComdat() {
225 return const_cast<Comdat *>(
226 static_cast<const GlobalValue *>(this)->getComdat());
227 }
228
229 VisibilityTypes getVisibility() const { return VisibilityTypes(Visibility); }
230 bool hasDefaultVisibility() const { return Visibility == DefaultVisibility; }
231 bool hasHiddenVisibility() const { return Visibility == HiddenVisibility; }
232 bool hasProtectedVisibility() const {
233 return Visibility == ProtectedVisibility;
234 }
235 void setVisibility(VisibilityTypes V) {
236 assert((!hasLocalLinkage() || V == DefaultVisibility) &&((void)0)
237 "local linkage requires default visibility")((void)0);
238 Visibility = V;
239 if (isImplicitDSOLocal())
240 setDSOLocal(true);
241 }
242
243 /// If the value is "Thread Local", its value isn't shared by the threads.
244 bool isThreadLocal() const { return getThreadLocalMode() != NotThreadLocal; }
5
Assuming the condition is false
6
Returning zero, which participates in a condition later
245 void setThreadLocal(bool Val) {
246 setThreadLocalMode(Val ? GeneralDynamicTLSModel : NotThreadLocal);
247 }
248 void setThreadLocalMode(ThreadLocalMode Val) {
249 assert(Val == NotThreadLocal || getValueID() != Value::FunctionVal)((void)0);
250 ThreadLocal = Val;
251 }
252 ThreadLocalMode getThreadLocalMode() const {
253 return static_cast<ThreadLocalMode>(ThreadLocal);
254 }
255
256 DLLStorageClassTypes getDLLStorageClass() const {
257 return DLLStorageClassTypes(DllStorageClass);
258 }
259 bool hasDLLImportStorageClass() const {
260 return DllStorageClass == DLLImportStorageClass;
261 }
262 bool hasDLLExportStorageClass() const {
263 return DllStorageClass == DLLExportStorageClass;
264 }
265 void setDLLStorageClass(DLLStorageClassTypes C) { DllStorageClass = C; }
266
267 bool hasSection() const { return !getSection().empty(); }
268 StringRef getSection() const;
269
270 /// Global values are always pointers.
271 PointerType *getType() const { return cast<PointerType>(User::getType()); }
272
273 Type *getValueType() const { return ValueType; }
274
275 bool isImplicitDSOLocal() const {
276 return hasLocalLinkage() ||
277 (!hasDefaultVisibility() && !hasExternalWeakLinkage());
278 }
279
280 void setDSOLocal(bool Local) { IsDSOLocal = Local; }
281
282 bool isDSOLocal() const {
283 return IsDSOLocal;
284 }
285
286 bool hasPartition() const {
287 return HasPartition;
288 }
289 StringRef getPartition() const;
290 void setPartition(StringRef Part);
291
292 static LinkageTypes getLinkOnceLinkage(bool ODR) {
293 return ODR ? LinkOnceODRLinkage : LinkOnceAnyLinkage;
294 }
295 static LinkageTypes getWeakLinkage(bool ODR) {
296 return ODR ? WeakODRLinkage : WeakAnyLinkage;
297 }
298
299 static bool isExternalLinkage(LinkageTypes Linkage) {
300 return Linkage == ExternalLinkage;
301 }
302 static bool isAvailableExternallyLinkage(LinkageTypes Linkage) {
303 return Linkage == AvailableExternallyLinkage;
304 }
305 static bool isLinkOnceODRLinkage(LinkageTypes Linkage) {
306 return Linkage == LinkOnceODRLinkage;
307 }
308 static bool isLinkOnceLinkage(LinkageTypes Linkage) {
309 return Linkage == LinkOnceAnyLinkage || Linkage == LinkOnceODRLinkage;
310 }
311 static bool isWeakAnyLinkage(LinkageTypes Linkage) {
312 return Linkage == WeakAnyLinkage;
313 }
314 static bool isWeakODRLinkage(LinkageTypes Linkage) {
315 return Linkage == WeakODRLinkage;
316 }
317 static bool isWeakLinkage(LinkageTypes Linkage) {
318 return isWeakAnyLinkage(Linkage) || isWeakODRLinkage(Linkage);
319 }
320 static bool isAppendingLinkage(LinkageTypes Linkage) {
321 return Linkage == AppendingLinkage;
322 }
323 static bool isInternalLinkage(LinkageTypes Linkage) {
324 return Linkage == InternalLinkage;
20
Assuming 'Linkage' is equal to InternalLinkage
21
Returning the value 1, which participates in a condition later
325 }
326 static bool isPrivateLinkage(LinkageTypes Linkage) {
327 return Linkage == PrivateLinkage;
328 }
329 static bool isLocalLinkage(LinkageTypes Linkage) {
330 return isInternalLinkage(Linkage) || isPrivateLinkage(Linkage);
331 }
332 static bool isExternalWeakLinkage(LinkageTypes Linkage) {
333 return Linkage == ExternalWeakLinkage;
334 }
335 static bool isCommonLinkage(LinkageTypes Linkage) {
336 return Linkage == CommonLinkage;
337 }
338 static bool isValidDeclarationLinkage(LinkageTypes Linkage) {
339 return isExternalWeakLinkage(Linkage) || isExternalLinkage(Linkage);
340 }
341
342 /// Whether the definition of this global may be replaced by something
343 /// non-equivalent at link time. For example, if a function has weak linkage
344 /// then the code defining it may be replaced by different code.
345 static bool isInterposableLinkage(LinkageTypes Linkage) {
346 switch (Linkage) {
347 case WeakAnyLinkage:
348 case LinkOnceAnyLinkage:
349 case CommonLinkage:
350 case ExternalWeakLinkage:
351 return true;
352
353 case AvailableExternallyLinkage:
354 case LinkOnceODRLinkage:
355 case WeakODRLinkage:
356 // The above three cannot be overridden but can be de-refined.
357
358 case ExternalLinkage:
359 case AppendingLinkage:
360 case InternalLinkage:
361 case PrivateLinkage:
362 return false;
363 }
364 llvm_unreachable("Fully covered switch above!")__builtin_unreachable();
365 }
366
367 /// Whether the definition of this global may be discarded if it is not used
368 /// in its compilation unit.
369 static bool isDiscardableIfUnused(LinkageTypes Linkage) {
370 return isLinkOnceLinkage(Linkage) || isLocalLinkage(Linkage) ||
371 isAvailableExternallyLinkage(Linkage);
372 }
373
374 /// Whether the definition of this global may be replaced at link time. NB:
375 /// Using this method outside of the code generators is almost always a
376 /// mistake: when working at the IR level use isInterposable instead as it
377 /// knows about ODR semantics.
378 static bool isWeakForLinker(LinkageTypes Linkage) {
379 return Linkage == WeakAnyLinkage || Linkage == WeakODRLinkage ||
380 Linkage == LinkOnceAnyLinkage || Linkage == LinkOnceODRLinkage ||
381 Linkage == CommonLinkage || Linkage == ExternalWeakLinkage;
382 }
383
384 /// Return true if the currently visible definition of this global (if any) is
385 /// exactly the definition we will see at runtime.
386 ///
387 /// Non-exact linkage types inhibits most non-inlining IPO, since a
388 /// differently optimized variant of the same function can have different
389 /// observable or undefined behavior than in the variant currently visible.
390 /// For instance, we could have started with
391 ///
392 /// void foo(int *v) {
393 /// int t = 5 / v[0];
394 /// (void) t;
395 /// }
396 ///
397 /// and "refined" it to
398 ///
399 /// void foo(int *v) { }
400 ///
401 /// However, we cannot infer readnone for `foo`, since that would justify
402 /// DSE'ing a store to `v[0]` across a call to `foo`, which can cause
403 /// undefined behavior if the linker replaces the actual call destination with
404 /// the unoptimized `foo`.
405 ///
406 /// Inlining is okay across non-exact linkage types as long as they're not
407 /// interposable (see \c isInterposable), since in such cases the currently
408 /// visible variant is *a* correct implementation of the original source
409 /// function; it just isn't the *only* correct implementation.
410 bool isDefinitionExact() const {
411 return !mayBeDerefined();
412 }
413
414 /// Return true if this global has an exact defintion.
415 bool hasExactDefinition() const {
416 // While this computes exactly the same thing as
417 // isStrongDefinitionForLinker, the intended uses are different. This
418 // function is intended to help decide if specific inter-procedural
419 // transforms are correct, while isStrongDefinitionForLinker's intended use
420 // is in low level code generation.
421 return !isDeclaration() && isDefinitionExact();
422 }
423
424 /// Return true if this global's definition can be substituted with an
425 /// *arbitrary* definition at link time or load time. We cannot do any IPO or
426 /// inlining across interposable call edges, since the callee can be
427 /// replaced with something arbitrary.
428 bool isInterposable() const;
429 bool canBenefitFromLocalAlias() const;
430
431 bool hasExternalLinkage() const { return isExternalLinkage(getLinkage()); }
432 bool hasAvailableExternallyLinkage() const {
433 return isAvailableExternallyLinkage(getLinkage());
434 }
435 bool hasLinkOnceLinkage() const { return isLinkOnceLinkage(getLinkage()); }
436 bool hasLinkOnceODRLinkage() const {
437 return isLinkOnceODRLinkage(getLinkage());
438 }
439 bool hasWeakLinkage() const { return isWeakLinkage(getLinkage()); }
440 bool hasWeakAnyLinkage() const { return isWeakAnyLinkage(getLinkage()); }
441 bool hasWeakODRLinkage() const { return isWeakODRLinkage(getLinkage()); }
442 bool hasAppendingLinkage() const { return isAppendingLinkage(getLinkage()); }
443 bool hasInternalLinkage() const { return isInternalLinkage(getLinkage()); }
19
Calling 'GlobalValue::isInternalLinkage'
22
Returning from 'GlobalValue::isInternalLinkage'
23
Returning the value 1, which participates in a condition later
444 bool hasPrivateLinkage() const { return isPrivateLinkage(getLinkage()); }
445 bool hasLocalLinkage() const { return isLocalLinkage(getLinkage()); }
446 bool hasExternalWeakLinkage() const {
447 return isExternalWeakLinkage(getLinkage());
448 }
449 bool hasCommonLinkage() const { return isCommonLinkage(getLinkage()); }
450 bool hasValidDeclarationLinkage() const {
451 return isValidDeclarationLinkage(getLinkage());
452 }
453
454 void setLinkage(LinkageTypes LT) {
455 if (isLocalLinkage(LT))
456 Visibility = DefaultVisibility;
457 Linkage = LT;
458 if (isImplicitDSOLocal())
459 setDSOLocal(true);
460 }
461 LinkageTypes getLinkage() const { return LinkageTypes(Linkage); }
462
463 bool isDiscardableIfUnused() const {
464 return isDiscardableIfUnused(getLinkage());
465 }
466
467 bool isWeakForLinker() const { return isWeakForLinker(getLinkage()); }
468
469protected:
470 /// Copy all additional attributes (those not needed to create a GlobalValue)
471 /// from the GlobalValue Src to this one.
472 void copyAttributesFrom(const GlobalValue *Src);
473
474public:
475 /// If the given string begins with the GlobalValue name mangling escape
476 /// character '\1', drop it.
477 ///
478 /// This function applies a specific mangling that is used in PGO profiles,
479 /// among other things. If you're trying to get a symbol name for an
480 /// arbitrary GlobalValue, this is not the function you're looking for; see
481 /// Mangler.h.
482 static StringRef dropLLVMManglingEscape(StringRef Name) {
483 if (!Name.empty() && Name[0] == '\1')
484 return Name.substr(1);
485 return Name;
486 }
487
488 /// Return the modified name for a global value suitable to be
489 /// used as the key for a global lookup (e.g. profile or ThinLTO).
490 /// The value's original name is \c Name and has linkage of type
491 /// \c Linkage. The value is defined in module \c FileName.
492 static std::string getGlobalIdentifier(StringRef Name,
493 GlobalValue::LinkageTypes Linkage,
494 StringRef FileName);
495
496 /// Return the modified name for this global value suitable to be
497 /// used as the key for a global lookup (e.g. profile or ThinLTO).
498 std::string getGlobalIdentifier() const;
499
500 /// Declare a type to represent a global unique identifier for a global value.
501 /// This is a 64 bits hash that is used by PGO and ThinLTO to have a compact
502 /// unique way to identify a symbol.
503 using GUID = uint64_t;
504
505 /// Return a 64-bit global unique ID constructed from global value name
506 /// (i.e. returned by getGlobalIdentifier()).
507 static GUID getGUID(StringRef GlobalName) { return MD5Hash(GlobalName); }
508
509 /// Return a 64-bit global unique ID constructed from global value name
510 /// (i.e. returned by getGlobalIdentifier()).
511 GUID getGUID() const { return getGUID(getGlobalIdentifier()); }
512
513 /// @name Materialization
514 /// Materialization is used to construct functions only as they're needed.
515 /// This
516 /// is useful to reduce memory usage in LLVM or parsing work done by the
517 /// BitcodeReader to load the Module.
518 /// @{
519
520 /// If this function's Module is being lazily streamed in functions from disk
521 /// or some other source, this method can be used to check to see if the
522 /// function has been read in yet or not.
523 bool isMaterializable() const;
524
525 /// Make sure this GlobalValue is fully read.
526 Error materialize();
527
528/// @}
529
530 /// Return true if the primary definition of this global value is outside of
531 /// the current translation unit.
532 bool isDeclaration() const;
533
534 bool isDeclarationForLinker() const {
535 if (hasAvailableExternallyLinkage())
536 return true;
537
538 return isDeclaration();
539 }
540
541 /// Returns true if this global's definition will be the one chosen by the
542 /// linker.
543 ///
544 /// NB! Ideally this should not be used at the IR level at all. If you're
545 /// interested in optimization constraints implied by the linker's ability to
546 /// choose an implementation, prefer using \c hasExactDefinition.
547 bool isStrongDefinitionForLinker() const {
548 return !(isDeclarationForLinker() || isWeakForLinker());
549 }
550
551 const GlobalObject *getBaseObject() const;
552 GlobalObject *getBaseObject() {
553 return const_cast<GlobalObject *>(
554 static_cast<const GlobalValue *>(this)->getBaseObject());
555 }
556
557 /// Returns whether this is a reference to an absolute symbol.
558 bool isAbsoluteSymbolRef() const;
559
560 /// If this is an absolute symbol reference, returns the range of the symbol,
561 /// otherwise returns None.
562 Optional<ConstantRange> getAbsoluteSymbolRange() const;
563
564 /// This method unlinks 'this' from the containing module, but does not delete
565 /// it.
566 void removeFromParent();
567
568 /// This method unlinks 'this' from the containing module and deletes it.
569 void eraseFromParent();
570
571 /// Get the module that this global value is contained inside of...
572 Module *getParent() { return Parent; }
573 const Module *getParent() const { return Parent; }
574
575 // Methods for support type inquiry through isa, cast, and dyn_cast:
576 static bool classof(const Value *V) {
577 return V->getValueID() == Value::FunctionVal ||
578 V->getValueID() == Value::GlobalVariableVal ||
579 V->getValueID() == Value::GlobalAliasVal ||
580 V->getValueID() == Value::GlobalIFuncVal;
581 }
582
583 /// True if GV can be left out of the object symbol table. This is the case
584 /// for linkonce_odr values whose address is not significant. While legal, it
585 /// is not normally profitable to omit them from the .o symbol table. Using
586 /// this analysis makes sense when the information can be passed down to the
587 /// linker or we are in LTO.
588 bool canBeOmittedFromSymbolTable() const;
589};
590
591} // end namespace llvm
592
593#endif // LLVM_IR_GLOBALVALUE_H

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IR/GlobalVariable.h

1//===-- llvm/GlobalVariable.h - GlobalVariable class ------------*- 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 the declaration of the GlobalVariable class, which
10// represents a single global variable (or constant) in the VM.
11//
12// Global variables are constant pointers that refer to hunks of space that are
13// allocated by either the VM, or by the linker in a static compiler. A global
14// variable may have an initial value, which is copied into the executables .data
15// area. Global Constants are required to have initializers.
16//
17//===----------------------------------------------------------------------===//
18
19#ifndef LLVM_IR_GLOBALVARIABLE_H
20#define LLVM_IR_GLOBALVARIABLE_H
21
22#include "llvm/ADT/Twine.h"
23#include "llvm/ADT/ilist_node.h"
24#include "llvm/IR/Attributes.h"
25#include "llvm/IR/GlobalObject.h"
26#include "llvm/IR/OperandTraits.h"
27#include "llvm/IR/Value.h"
28#include <cassert>
29#include <cstddef>
30
31namespace llvm {
32
33class Constant;
34class Module;
35
36template <typename ValueSubClass> class SymbolTableListTraits;
37class DIGlobalVariable;
38class DIGlobalVariableExpression;
39
40class GlobalVariable : public GlobalObject, public ilist_node<GlobalVariable> {
41 friend class SymbolTableListTraits<GlobalVariable>;
42
43 AttributeSet Attrs;
44 bool isConstantGlobal : 1; // Is this a global constant?
45 bool isExternallyInitializedConstant : 1; // Is this a global whose value
46 // can change from its initial
47 // value before global
48 // initializers are run?
49
50public:
51 /// GlobalVariable ctor - If a parent module is specified, the global is
52 /// automatically inserted into the end of the specified modules global list.
53 GlobalVariable(Type *Ty, bool isConstant, LinkageTypes Linkage,
54 Constant *Initializer = nullptr, const Twine &Name = "",
55 ThreadLocalMode = NotThreadLocal, unsigned AddressSpace = 0,
56 bool isExternallyInitialized = false);
57 /// GlobalVariable ctor - This creates a global and inserts it before the
58 /// specified other global.
59 GlobalVariable(Module &M, Type *Ty, bool isConstant, LinkageTypes Linkage,
60 Constant *Initializer, const Twine &Name = "",
61 GlobalVariable *InsertBefore = nullptr,
62 ThreadLocalMode = NotThreadLocal,
63 Optional<unsigned> AddressSpace = None,
64 bool isExternallyInitialized = false);
65 GlobalVariable(const GlobalVariable &) = delete;
66 GlobalVariable &operator=(const GlobalVariable &) = delete;
67
68 ~GlobalVariable() {
69 dropAllReferences();
70 }
71
72 // allocate space for exactly one operand
73 void *operator new(size_t s) {
74 return User::operator new(s, 1);
75 }
76
77 // delete space for exactly one operand as created in the corresponding new operator
78 void operator delete(void *ptr){
79 assert(ptr != nullptr && "must not be nullptr")((void)0);
80 User *Obj = static_cast<User *>(ptr);
81 // Number of operands can be set to 0 after construction and initialization. Make sure
82 // that number of operands is reset to 1, as this is needed in User::operator delete
83 Obj->setGlobalVariableNumOperands(1);
84 User::operator delete(Obj);
85 }
86
87 /// Provide fast operand accessors
88 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value)public: inline Value *getOperand(unsigned) const; inline void
setOperand(unsigned, Value*); inline op_iterator op_begin();
inline const_op_iterator op_begin() const; inline op_iterator
op_end(); inline const_op_iterator op_end() const; protected
: template <int> inline Use &Op(); template <int
> inline const Use &Op() const; public: inline unsigned
getNumOperands() const
;
89
90 /// Definitions have initializers, declarations don't.
91 ///
92 inline bool hasInitializer() const { return !isDeclaration(); }
93
94 /// hasDefinitiveInitializer - Whether the global variable has an initializer,
95 /// and any other instances of the global (this can happen due to weak
96 /// linkage) are guaranteed to have the same initializer.
97 ///
98 /// Note that if you want to transform a global, you must use
99 /// hasUniqueInitializer() instead, because of the *_odr linkage type.
100 ///
101 /// Example:
102 ///
103 /// @a = global SomeType* null - Initializer is both definitive and unique.
104 ///
105 /// @b = global weak SomeType* null - Initializer is neither definitive nor
106 /// unique.
107 ///
108 /// @c = global weak_odr SomeType* null - Initializer is definitive, but not
109 /// unique.
110 inline bool hasDefinitiveInitializer() const {
111 return hasInitializer() &&
112 // The initializer of a global variable may change to something arbitrary
113 // at link time.
114 !isInterposable() &&
115 // The initializer of a global variable with the externally_initialized
116 // marker may change at runtime before C++ initializers are evaluated.
117 !isExternallyInitialized();
118 }
119
120 /// hasUniqueInitializer - Whether the global variable has an initializer, and
121 /// any changes made to the initializer will turn up in the final executable.
122 inline bool hasUniqueInitializer() const {
123 return
124 // We need to be sure this is the definition that will actually be used
125 isStrongDefinitionForLinker() &&
126 // It is not safe to modify initializers of global variables with the
127 // external_initializer marker since the value may be changed at runtime
128 // before C++ initializers are evaluated.
129 !isExternallyInitialized();
130 }
131
132 /// getInitializer - Return the initializer for this global variable. It is
133 /// illegal to call this method if the global is external, because we cannot
134 /// tell what the value is initialized to!
135 ///
136 inline const Constant *getInitializer() const {
137 assert(hasInitializer() && "GV doesn't have initializer!")((void)0);
138 return static_cast<Constant*>(Op<0>().get());
139 }
140 inline Constant *getInitializer() {
141 assert(hasInitializer() && "GV doesn't have initializer!")((void)0);
142 return static_cast<Constant*>(Op<0>().get());
143 }
144 /// setInitializer - Sets the initializer for this global variable, removing
145 /// any existing initializer if InitVal==NULL. If this GV has type T*, the
146 /// initializer must have type T.
147 void setInitializer(Constant *InitVal);
148
149 /// If the value is a global constant, its value is immutable throughout the
150 /// runtime execution of the program. Assigning a value into the constant
151 /// leads to undefined behavior.
152 ///
153 bool isConstant() const { return isConstantGlobal; }
154 void setConstant(bool Val) { isConstantGlobal = Val; }
155
156 bool isExternallyInitialized() const {
157 return isExternallyInitializedConstant;
158 }
159 void setExternallyInitialized(bool Val) {
160 isExternallyInitializedConstant = Val;
161 }
162
163 /// copyAttributesFrom - copy all additional attributes (those not needed to
164 /// create a GlobalVariable) from the GlobalVariable Src to this one.
165 void copyAttributesFrom(const GlobalVariable *Src);
166
167 /// removeFromParent - This method unlinks 'this' from the containing module,
168 /// but does not delete it.
169 ///
170 void removeFromParent();
171
172 /// eraseFromParent - This method unlinks 'this' from the containing module
173 /// and deletes it.
174 ///
175 void eraseFromParent();
176
177 /// Drop all references in preparation to destroy the GlobalVariable. This
178 /// drops not only the reference to the initializer but also to any metadata.
179 void dropAllReferences();
180
181 /// Attach a DIGlobalVariableExpression.
182 void addDebugInfo(DIGlobalVariableExpression *GV);
183
184 /// Fill the vector with all debug info attachements.
185 void getDebugInfo(SmallVectorImpl<DIGlobalVariableExpression *> &GVs) const;
186
187 /// Add attribute to this global.
188 void addAttribute(Attribute::AttrKind Kind) {
189 Attrs = Attrs.addAttribute(getContext(), Kind);
190 }
191
192 /// Add attribute to this global.
193 void addAttribute(StringRef Kind, StringRef Val = StringRef()) {
194 Attrs = Attrs.addAttribute(getContext(), Kind, Val);
195 }
196
197 /// Return true if the attribute exists.
198 bool hasAttribute(Attribute::AttrKind Kind) const {
199 return Attrs.hasAttribute(Kind);
200 }
201
202 /// Return true if the attribute exists.
203 bool hasAttribute(StringRef Kind) const {
204 return Attrs.hasAttribute(Kind);
205 }
206
207 /// Return true if any attributes exist.
208 bool hasAttributes() const {
209 return Attrs.hasAttributes();
210 }
211
212 /// Return the attribute object.
213 Attribute getAttribute(Attribute::AttrKind Kind) const {
214 return Attrs.getAttribute(Kind);
215 }
216
217 /// Return the attribute object.
218 Attribute getAttribute(StringRef Kind) const {
219 return Attrs.getAttribute(Kind);
220 }
221
222 /// Return the attribute set for this global
223 AttributeSet getAttributes() const {
224 return Attrs;
225 }
226
227 /// Return attribute set as list with index.
228 /// FIXME: This may not be required once ValueEnumerators
229 /// in bitcode-writer can enumerate attribute-set.
230 AttributeList getAttributesAsList(unsigned index) const {
231 if (!hasAttributes())
232 return AttributeList();
233 std::pair<unsigned, AttributeSet> AS[1] = {{index, Attrs}};
234 return AttributeList::get(getContext(), AS);
235 }
236
237 /// Set attribute list for this global
238 void setAttributes(AttributeSet A) {
239 Attrs = A;
240 }
241
242 /// Check if section name is present
243 bool hasImplicitSection() const {
244 return getAttributes().hasAttribute("bss-section") ||
9
Assuming the condition is false
12
Returning value, which participates in a condition later
245 getAttributes().hasAttribute("data-section") ||
10
Assuming the condition is false
246 getAttributes().hasAttribute("relro-section") ||
11
Assuming the condition is false
247 getAttributes().hasAttribute("rodata-section");
248 }
249
250 // Methods for support type inquiry through isa, cast, and dyn_cast:
251 static bool classof(const Value *V) {
252 return V->getValueID() == Value::GlobalVariableVal;
253 }
254};
255
256template <>
257struct OperandTraits<GlobalVariable> :
258 public OptionalOperandTraits<GlobalVariable> {
259};
260
261DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalVariable, Value)GlobalVariable::op_iterator GlobalVariable::op_begin() { return
OperandTraits<GlobalVariable>::op_begin(this); } GlobalVariable
::const_op_iterator GlobalVariable::op_begin() const { return
OperandTraits<GlobalVariable>::op_begin(const_cast<
GlobalVariable*>(this)); } GlobalVariable::op_iterator GlobalVariable
::op_end() { return OperandTraits<GlobalVariable>::op_end
(this); } GlobalVariable::const_op_iterator GlobalVariable::op_end
() const { return OperandTraits<GlobalVariable>::op_end
(const_cast<GlobalVariable*>(this)); } Value *GlobalVariable
::getOperand(unsigned i_nocapture) const { ((void)0); return cast_or_null
<Value>( OperandTraits<GlobalVariable>::op_begin(
const_cast<GlobalVariable*>(this))[i_nocapture].get());
} void GlobalVariable::setOperand(unsigned i_nocapture, Value
*Val_nocapture) { ((void)0); OperandTraits<GlobalVariable
>::op_begin(this)[i_nocapture] = Val_nocapture; } unsigned
GlobalVariable::getNumOperands() const { return OperandTraits
<GlobalVariable>::operands(this); } template <int Idx_nocapture
> Use &GlobalVariable::Op() { return this->OpFrom<
Idx_nocapture>(this); } template <int Idx_nocapture>
const Use &GlobalVariable::Op() const { return this->
OpFrom<Idx_nocapture>(this); }
262
263} // end namespace llvm
264
265#endif // LLVM_IR_GLOBALVARIABLE_H