From: Naomi Musgrave <nmusgrave@google.com>
Date: Thu, 30 Jul 2015 17:59:46 +0000 (+0000)
Subject: repress tail call optimization when performing use-after-dtor sanitization
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a9e7bb515f202e59464c011dc3b4bfab19a8ba21;p=clang

repress tail call optimization when performing use-after-dtor sanitization

Reviewers: eugenis, kcc

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D11613

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@243668 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGClass.cpp b/lib/CodeGen/CGClass.cpp
index ac96afe31b..a078beb9da 100644
--- a/lib/CodeGen/CGClass.cpp
+++ b/lib/CodeGen/CGClass.cpp
@@ -1369,6 +1369,8 @@ static bool CanSkipVTablePointerInitialization(ASTContext &Context,
 
 // Generates function call for handling object poisoning, passing in
 // references to 'this' and its size as arguments.
+// Disables tail call elimination, to save emitted callback from
+// being optimized away.
 static void EmitDtorSanitizerCallback(CodeGenFunction &CGF,
                                       const CXXDestructorDecl *Dtor) {
   const ASTRecordLayout &Layout =
@@ -1383,6 +1385,8 @@ static void EmitDtorSanitizerCallback(CodeGenFunction &CGF,
       llvm::FunctionType::get(CGF.VoidTy, ArgTypes, false);
   llvm::Value *Fn =
       CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback");
+
+  CGF.CurFn->addFnAttr("disable-tail-calls", "true");
   CGF.EmitNounwindRuntimeCall(Fn, Args);
 }
 
diff --git a/test/CodeGenCXX/sanitize-dtor-tail-call.cpp b/test/CodeGenCXX/sanitize-dtor-tail-call.cpp
new file mode 100644
index 0000000000..c82f074638
--- /dev/null
+++ b/test/CodeGenCXX/sanitize-dtor-tail-call.cpp
@@ -0,0 +1,20 @@
+// Test -fsanitize-memory-use-after-dtor
+// RUN: %clang_cc1 -O1 -fsanitize=memory -fsanitize-memory-use-after-dtor -std=c++11 -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s
+
+struct Simple {
+  int x_;
+  Simple() {
+    x_ = 5;
+  }
+  ~Simple() {
+    x_ += 1;
+  }
+};
+
+Simple s;
+// Simple internal member is poisoned by compiler-generated dtor
+// CHECK-LABEL: define {{.*}}SimpleD2Ev
+// CHECK: {{\s*}}call void @__sanitizer_dtor_callback
+// CHECK-NOT: {{\s*}}call void @__sanitizer_dtor_callback
+// CHECK-NOT: {{\s*}}tail call void @__sanitizer_dtor_callback
+// CHECK: ret void