move GetOrCreateFunctionComdat to Instrumentation.cpp/Instrumentation.h

[kcc]

Summary

GetOrCreateFunctionComdat is currently used in SanitizerCoverage,
where it's defined. I'm planing to use it in HWASAN as well,
so moving it into a common location.
NFC

[morehouse]

include/llvm/Transforms/Instrumentation.h

46

Otherwise

include/llvm/Transforms/Instrumentation.h

 #include <string>
 #include <vector>
 
 namespace llvm {
 
 class FunctionPass;
 class ModulePass;
 class OptimizationRemarkEmitter;
+class Comdat;
 
 /// Instrumentation passes often insert conditional checks into entry blocks.
 /// Call this function before splitting the entry block to move instructions
 /// that must remain in the entry block up before the split point. Static
 /// allocas and llvm.localescape calls, for example, must remain in the entry
 /// block.
 BasicBlock::iterator PrepareToSplitEntryBlock(BasicBlock &BB,
                                               BasicBlock::iterator IP);
 
 // Create a constant for Str so that we can pass it to the run-time lib.
 GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,
                                              bool AllowMerging,
                                              const char *NamePrefix = "");
 
+// Returns F.getComdat() if it exists.
+// Otherwie creates a new comdat, sets F's comdat, and returns it.
+// Returns nullptr on failure.
+Comdat *GetOrCreateFunctionComdat(Function &F, const std::string &ModuleId);
+
 // Insert GCOV profiling instrumentation
 struct GCOVOptions {
   static GCOVOptions getDefault();
 
   // Specify whether to emit .gcno files.
   bool EmitNotes;
 
   // Specify whether to modify the program to emit .gcda files when run.

lib/Transforms/Instrumentation/Instrumentation.cpp

GlobalVariable *GV =
       new GlobalVariable(M, StrConst->getType(), true,
                          GlobalValue::PrivateLinkage, StrConst, NamePrefix);
   if (AllowMerging)
     GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
   GV->setAlignment(1);  // Strings may not be merged w/o setting align 1.
   return GV;
 }
 
+Comdat *llvm::GetOrCreateFunctionComdat(Function &F,
+                                        const std::string &ModuleId) {
+  if (auto Comdat = F.getComdat()) return Comdat;
+  assert(F.hasName());
+  Module *M = F.getParent();
+  std::string Name = F.getName();
+  if (F.hasLocalLinkage()) {
+    if (ModuleId.empty())
+      return nullptr;
+    Name += ModuleId;
+  }
+  F.setComdat(M->getOrInsertComdat(Name));
+  return F.getComdat();
+}
+
 /// initializeInstrumentation - Initialize all passes in the TransformUtils
 /// library.
 void llvm::initializeInstrumentation(PassRegistry &Registry) {
   initializeAddressSanitizerLegacyPassPass(Registry);
   initializeAddressSanitizerModuleLegacyPassPass(Registry);
   initializeBoundsCheckingLegacyPassPass(Registry);
   initializeControlHeightReductionLegacyPassPass(Registry);
   initializeGCOVProfilerLegacyPassPass(Registry);

lib/Transforms/Instrumentation/SanitizerCoverage.cpp

private:
   std::pair<GlobalVariable *, GlobalVariable *>
   CreateSecStartEnd(Module &M, const char *Section, Type *Ty);
 
   void SetNoSanitizeMetadata(Instruction *I) {
     I->setMetadata(I->getModule()->getMDKindID("nosanitize"),
                    MDNode::get(*C, None));
   }
 
-  Comdat *GetOrCreateFunctionComdat(Function &F);
-
   std::string getSectionName(const std::string &Section) const;
   std::string getSectionStart(const std::string &Section) const;
   std::string getSectionEnd(const std::string &Section) const;
   Function *SanCovTracePCIndir;
   Function *SanCovTracePC, *SanCovTracePCGuard;
   Function *SanCovTraceCmpFunction[4];
   Function *SanCovTraceConstCmpFunction[4];
   Function *SanCovTraceDivFunction[2];
bool SanitizerCoverageModule::runOnFunction(Function &F) {
   InjectCoverageForIndirectCalls(F, IndirCalls);
   InjectTraceForCmp(F, CmpTraceTargets);
   InjectTraceForSwitch(F, SwitchTraceTargets);
   InjectTraceForDiv(F, DivTraceTargets);
   InjectTraceForGep(F, GepTraceTargets);
   return true;
 }
 
-Comdat *SanitizerCoverageModule::GetOrCreateFunctionComdat(Function &F) {
-  if (auto Comdat = F.getComdat()) return Comdat;
-  if (!TargetTriple.isOSBinFormatELF()) return nullptr;
-  assert(F.hasName());
-  std::string Name = F.getName();
-  if (F.hasLocalLinkage()) {
-    if (CurModuleUniqueId.empty()) return nullptr;
-    Name += CurModuleUniqueId;
-  }
-  auto Comdat = CurModule->getOrInsertComdat(Name);
-  F.setComdat(Comdat);
-  return Comdat;
-}
-
 GlobalVariable *SanitizerCoverageModule::CreateFunctionLocalArrayInSection(
     size_t NumElements, Function &F, Type *Ty, const char *Section) {
   ArrayType *ArrayTy = ArrayType::get(Ty, NumElements);
   auto Array = new GlobalVariable(
       *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
       Constant::getNullValue(ArrayTy), "__sancov_gen_");
-  if (auto Comdat = GetOrCreateFunctionComdat(F))
+
+  if (TargetTriple.isOSBinFormatELF())
+    if (auto Comdat = GetOrCreateFunctionComdat(F, CurModuleUniqueId))
       Array->setComdat(Comdat);
   Array->setSection(getSectionName(Section));
   Array->setAlignment(Ty->isPointerTy() ? DL->getPointerSize()
                                         : Ty->getPrimitiveSizeInBits() / 8);
   GlobalsToAppendToUsed.push_back(Array);
   GlobalsToAppendToCompilerUsed.push_back(Array);
   MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F));
   Array->addMetadata(LLVMContext::MD_associated, *MD);