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[asan] Fix dynamic allocas unpoisoning on PowerPC64.

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For PowerPC64 we cannot just pass SP extracted from @llvm.stackrestore to
_asan_allocas_unpoison due to specific ABI requirements
(http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#DYNAM-STACK).
This patch adds the value returned by @llvm.get.dynamic.area.offset to
extracted from @llvm.stackrestore stack pointer, so dynamic allocas unpoisoning
stuff would work correctly on PowerPC64.

Patch by Max Ostapenko.

Differential Revision: http://reviews.llvm.org/D15108


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254707 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Yury Gribov 2015-12-04 09:19:14 +00:00
parent 9ce890e1fe
commit 008021cd33
1 changed files with 17 additions and 2 deletions
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19
lib/Transforms/Instrumentation/AddressSanitizer.cpp
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@ -624,9 +624,24 @@ struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
void unpoisonDynamicAllocasBeforeInst(Instruction *InstBefore,
Value *SavedStack) {
IRBuilder<> IRB(InstBefore);
Value *DynamicAreaPtr = IRB.CreatePtrToInt(SavedStack, IntptrTy);
// When we insert _asan_allocas_unpoison before @llvm.stackrestore, we
// need to adjust extracted SP to compute the address of the most recent
// alloca. We have a special @llvm.get.dynamic.area.offset intrinsic for
// this purpose.
if (!isa<ReturnInst>(InstBefore)) {
Function *DynamicAreaOffsetFunc = Intrinsic::getDeclaration(
InstBefore->getModule(), Intrinsic::get_dynamic_area_offset,
{IntptrTy});
Value *DynamicAreaOffset = IRB.CreateCall(DynamicAreaOffsetFunc, {});
DynamicAreaPtr = IRB.CreateAdd(IRB.CreatePtrToInt(SavedStack, IntptrTy),
DynamicAreaOffset);
}
IRB.CreateCall(AsanAllocasUnpoisonFunc,
{IRB.CreateLoad(DynamicAllocaLayout),
IRB.CreatePtrToInt(SavedStack, IntptrTy)});
{IRB.CreateLoad(DynamicAllocaLayout), DynamicAreaPtr});
}
// Unpoison dynamic allocas redzones.