r235613 - Don't emit lifetime markers when msan is enabled

[Reid Kleckner]

Author: rnk
Date: Thu Apr 23 13:07:13 2015
New Revision: 235613

URL: http://llvm.org/viewvc/llvm-project?rev=235613&view=rev
Log:
Don't emit lifetime markers when msan is enabled

In r235553, Clang started emitting lifetime markers more often. This
caused false negative in MSan, because MSan only poisons all allocas
once at function entry. Eventually, MSan should poison allocas at
lifetime start and probably also lifetime end, but until then, let's not
emit markers that aren't going to be useful.

Modified:
    cfe/trunk/lib/CodeGen/CGDecl.cpp
    cfe/trunk/test/CodeGen/cleanup-destslot-simple.c

Modified: cfe/trunk/lib/CodeGen/CGDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDecl.cpp?rev=235613&r1=235612&r2=235613&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDecl.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGDecl.cpp Thu Apr 23 13:07:13 2015
@@ -856,6 +856,11 @@ llvm::Value *CodeGenFunction::EmitLifeti
   if (CGM.getCodeGenOpts().OptimizationLevel == 0)
     return nullptr;
 
+  // Disable lifetime markers in msan builds.
+  // FIXME: Remove this when msan works with lifetime markers.
+  if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
+    return nullptr;
+
   llvm::Value *SizeV = llvm::ConstantInt::get(Int64Ty, Size);
   llvm::Value *Args[] = {
       SizeV,

Modified: cfe/trunk/test/CodeGen/cleanup-destslot-simple.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/cleanup-destslot-simple.c?rev=235613&r1=235612&r2=235613&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/cleanup-destslot-simple.c (original)
+++ cfe/trunk/test/CodeGen/cleanup-destslot-simple.c Thu Apr 23 13:07:13 2015
@@ -1,4 +1,8 @@
-// RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s
+// RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=LIFETIME
+
+// We shouldn't have markers at -O0 or with msan.
+// RUN: %clang_cc1 -O0 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s --check-prefix=CHECK
+// RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - -fsanitize=memory | FileCheck %s --check-prefix=CHECK
 
 // There is no exception to handle here, lifetime.end is not a destructor,
 // so there is no need have cleanup dest slot related code
@@ -9,7 +13,7 @@ int test() {
   return *p;
 // CHECK: [[X:%.*]] = alloca i32
 // CHECK: [[P:%.*]] = alloca i32*
-// CHECK: call void @llvm.lifetime.start(i64 4, i8* %{{.*}})
-// CHECK: call void @llvm.lifetime.start(i64 8, i8* %{{.*}})
+// LIFETIME: call void @llvm.lifetime.start(i64 4, i8* %{{.*}})
+// LIFETIME: call void @llvm.lifetime.start(i64 8, i8* %{{.*}})
 // CHECK-NOT: store i32 %{{.*}}, i32* %cleanup.dest.slot
 }