private:
void initializeCallbacks(Module &M);
- bool InstrumentGlobals(IRBuilder<> &IRB, Module &M);
+ bool InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool *CtorComdat);
void InstrumentGlobalsCOFF(IRBuilder<> &IRB, Module &M,
ArrayRef<GlobalVariable *> ExtendedGlobals,
ArrayRef<Constant *> MetadataInitializers);
Function *AsanUnregisterGlobals;
Function *AsanRegisterImageGlobals;
Function *AsanUnregisterImageGlobals;
+
+ Function *AsanCtorFunction = nullptr;
+ Function *AsanDtorFunction = nullptr;
};
// Stack poisoning does not play well with exception handling.
void AddressSanitizerModule::createInitializerPoisonCalls(
Module &M, GlobalValue *ModuleName) {
GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
+ if (!GV)
+ return;
+
+ ConstantArray *CA = dyn_cast<ConstantArray>(GV->getInitializer());
+ if (!CA)
+ return;
- ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
for (Use &OP : CA->operands()) {
if (isa<ConstantAggregateZero>(OP)) continue;
ConstantStruct *CS = cast<ConstantStruct>(OP);
}
IRBuilder<> AddressSanitizerModule::CreateAsanModuleDtor(Module &M) {
- Function *AsanDtorFunction =
+ AsanDtorFunction =
Function::Create(FunctionType::get(Type::getVoidTy(*C), false),
GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
- appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
return IRBuilder<>(ReturnInst::Create(*C, AsanDtorBB));
}
// This function replaces all global variables with new variables that have
// trailing redzones. It also creates a function that poisons
// redzones and inserts this function into llvm.global_ctors.
-bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
+// Sets *CtorComdat to true if the global registration code emitted into the
+// asan constructor is comdat-compatible.
+bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool *CtorComdat) {
+ *CtorComdat = false;
GlobalsMD.init(M);
SmallVector<GlobalVariable *, 16> GlobalsToChange;
}
size_t n = GlobalsToChange.size();
- if (n == 0) return false;
+ if (n == 0) {
+ *CtorComdat = true;
+ return false;
+ }
auto &DL = M.getDataLayout();
if (CompileKernel)
return false;
- Function *AsanCtorFunction;
+ // Create a module constructor. A destructor is created lazily because not all
+ // platforms, and not all modules need it.
std::tie(AsanCtorFunction, std::ignore) = createSanitizerCtorAndInitFunctions(
M, kAsanModuleCtorName, kAsanInitName, /*InitArgTypes=*/{},
/*InitArgs=*/{}, kAsanVersionCheckName);
- appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
+ bool CtorComdat = true;
bool Changed = false;
// TODO(glider): temporarily disabled globals instrumentation for KASan.
if (ClGlobals) {
IRBuilder<> IRB(AsanCtorFunction->getEntryBlock().getTerminator());
- Changed |= InstrumentGlobals(IRB, M);
+ Changed |= InstrumentGlobals(IRB, M, &CtorComdat);
+ }
+
+ // Put the constructor and destructor in comdat if both
+ // (1) global instrumentation is not TU-specific
+ // (2) target is ELF.
+ if (TargetTriple.isOSBinFormatELF() && CtorComdat) {
+ AsanCtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleCtorName));
+ appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority,
+ AsanCtorFunction);
+ if (AsanDtorFunction) {
+ AsanDtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleDtorName));
+ appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority,
+ AsanDtorFunction);
+ }
+ } else {
+ appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
+ if (AsanDtorFunction)
+ appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
}
return Changed;