[asan] don't instrument globals that we've created ourselves (reduces the binary size a bit)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167230 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 25 insertions, 3 deletions

diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index adf7f0f200..0c6a406203 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -215,6 +215,7 @@ struct AddressSanitizer : public FunctionPass {
   Function *AsanErrorCallback[2][kNumberOfAccessSizes];
   InlineAsm *EmptyAsm;
   SmallSet<GlobalValue*, 32> DynamicallyInitializedGlobals;
+  SmallSet<GlobalValue*, 32> GlobalsCreatedByAsan;
 };
 
 }  // namespace
@@ -508,6 +509,7 @@ bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
   if (BL->isIn(*G)) return false;
   if (!Ty->isSized()) return false;
   if (!G->hasInitializer()) return false;
+  if (GlobalsCreatedByAsan.count(G)) return false; // Our own global.
   // Touch only those globals that will not be defined in other modules.
   // Don't handle ODR type linkages since other modules may be built w/o asan.
   if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
@@ -1090,9 +1092,10 @@ bool AddressSanitizer::poisonStackInFunction(Function &F) {
   Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
                                    ConstantInt::get(IntptrTy, LongSize/8));
   BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
-  Value *Description = IRB.CreatePointerCast(
-      createPrivateGlobalForString(*F.getParent(), StackDescription.str()),
-      IntptrTy);
+  GlobalVariable *StackDescriptionGlobal = 
+      createPrivateGlobalForString(*F.getParent(), StackDescription.str());
+  GlobalsCreatedByAsan.insert(StackDescriptionGlobal);
+  Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
   IRB.CreateStore(Description, BasePlus1);
 
   // Poison the stack redzones at the entry.
diff --git a/test/Instrumentation/AddressSanitizer/do-not-instrument-internal-globals.ll b/test/Instrumentation/AddressSanitizer/do-not-instrument-internal-globals.ll
new file mode 100644
index 0000000000..28d4ac0c0f
--- /dev/null
+++ b/test/Instrumentation/AddressSanitizer/do-not-instrument-internal-globals.ll
@@ -0,0 +1,19 @@
+; This test checks that we are not instrumenting globals
+; that we created ourselves.
+; RUN: opt < %s -asan -S | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @_Z3barv() uwtable address_safety {
+entry:
+  %a = alloca i32, align 4
+  call void @_Z3fooPi(i32* %a)
+  ret void
+}
+
+declare void @_Z3fooPi(i32*)
+; We create one global string constant for the stack frame above.
+; Make sure we don't create any other global constants.
+; CHECK: = private constant
+; CHECK-NOT: = private constant