[asan] Delay creation of asan ctor.

Create the constructor in the module pass.
This in needed for the GC-friendly globals change, where the constructor can be
put in a comdat  in some cases, but we don't know about that in the function
pass.

This is a rebase of r298731 which was reverted due to a false alarm.

llvm-svn: 299695

1 files changed, 13 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
index 617c8f7175d..dbe42c201dd 100644
--- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -138,6 +138,17 @@ Function *llvm::checkSanitizerInterfaceFunction(Constant *FuncOrBitcast) {
   report_fatal_error(Err);
 }
 
+Function *llvm::declareSanitizerInitFunction(Module &M, StringRef InitName,
+                                             ArrayRef<Type *> InitArgTypes) {
+  assert(!InitName.empty() && "Expected init function name");
+  Function *F = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+      InitName,
+      FunctionType::get(Type::getVoidTy(M.getContext()), InitArgTypes, false),
+      AttributeList()));
+  F->setLinkage(Function::ExternalLinkage);
+  return F;
+}
+
 std::pair<Function *, Function *> llvm::createSanitizerCtorAndInitFunctions(
     Module &M, StringRef CtorName, StringRef InitName,
     ArrayRef<Type *> InitArgTypes, ArrayRef<Value *> InitArgs,
@@ -145,16 +156,13 @@ std::pair<Function *, Function *> llvm::createSanitizerCtorAndInitFunctions(
   assert(!InitName.empty() && "Expected init function name");
   assert(InitArgs.size() == InitArgTypes.size() &&
          "Sanitizer's init function expects different number of arguments");
+  Function *InitFunction =
+      declareSanitizerInitFunction(M, InitName, InitArgTypes);
   Function *Ctor = Function::Create(
       FunctionType::get(Type::getVoidTy(M.getContext()), false),
       GlobalValue::InternalLinkage, CtorName, &M);
   BasicBlock *CtorBB = BasicBlock::Create(M.getContext(), "", Ctor);
   IRBuilder<> IRB(ReturnInst::Create(M.getContext(), CtorBB));
-  Function *InitFunction =
-      checkSanitizerInterfaceFunction(M.getOrInsertFunction(
-          InitName, FunctionType::get(IRB.getVoidTy(), InitArgTypes, false),
-          AttributeList()));
-  InitFunction->setLinkage(Function::ExternalLinkage);
   IRB.CreateCall(InitFunction, InitArgs);
   if (!VersionCheckName.empty()) {
     Function *VersionCheckFunction =