[asan] Fix dynamic allocas unpoisoning on PowerPC64.

[oota-llvm.git] / lib / Transforms / Instrumentation / AddressSanitizer.cpp

diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 8eb82e39b8a689d9906b2a97415fd1b6d389d9cf..dea94a514fe8ffcf6450914c93626f4f7cbac72a 100644 (file)
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -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.