From: Kostya Serebryany <kcc@google.com>
Date: Fri, 31 Oct 2014 19:01:02 +0000 (+0000)
Subject: ignore -mconstructor-aliases when adding field paddings for asan
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=083a9aac147fbf437d4f9079d6dd7acfbbdc71b5;p=clang

ignore -mconstructor-aliases when adding field paddings for asan

Summary:
When we are adding field paddings for asan even an empty dtor has to remain in the code,
so we ignore -mconstructor-aliases if the paddings are going to be added.

Test Plan: added a test

Reviewers: rsmith, rnk, rafael

Reviewed By: rafael

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D6038

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220986 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index a590afae0b..e467891d10 100644
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -46,6 +46,11 @@ bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
 
   const CXXRecordDecl *Class = D->getParent();
 
+  // We are going to instrument this destructor, so give up even if it is
+  // currently empty.
+  if (Class->mayInsertExtraPadding())
+    return true;
+
   // If we need to manipulate a VTT parameter, give up.
   if (Class->getNumVBases()) {
     // Extra Credit:  passing extra parameters is perfectly safe
diff --git a/test/CodeGen/sanitize-address-field-padding.cpp b/test/CodeGen/sanitize-address-field-padding.cpp
index 5f049bb005..0d09a133d4 100644
--- a/test/CodeGen/sanitize-address-field-padding.cpp
+++ b/test/CodeGen/sanitize-address-field-padding.cpp
@@ -2,6 +2,7 @@
 // RUN: echo 'type:SomeNamespace::BlacklistedByName=field-padding' > %t.type.blacklist
 // RUN: echo 'src:*sanitize-address-field-padding.cpp=field-padding' > %t.file.blacklist
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsanitize=address -fsanitize-address-field-padding=1 -fsanitize-blacklist=%t.type.blacklist -Rsanitize-address -emit-llvm -o - %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsanitize=address -fsanitize-address-field-padding=1 -fsanitize-blacklist=%t.type.blacklist -Rsanitize-address -emit-llvm -o - %s -O1 -mconstructor-aliases 2>&1 | FileCheck %s --check-prefix=WITH_CTOR_ALIASES
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsanitize=address -fsanitize-address-field-padding=1 -fsanitize-blacklist=%t.file.blacklist -Rsanitize-address -emit-llvm -o - %s 2>&1 | FileCheck %s --check-prefix=FILE_BLACKLIST
 // RUN: %clang_cc1 -fsanitize=address -emit-llvm -o - %s 2>&1 | FileCheck %s --check-prefix=NO_PADDING
 // REQUIRES: shell
@@ -193,3 +194,27 @@ ExternCStruct extern_C_struct;
 // CHECK-NOT: __asan_poison_intra_object_redzone
 // CHECK: ret void
 //
+
+struct WithVirtualDtor {
+  virtual ~WithVirtualDtor();
+  int x, y;
+};
+struct InheritsFrom_WithVirtualDtor: WithVirtualDtor {
+  int a, b;
+  InheritsFrom_WithVirtualDtor() {}
+  ~InheritsFrom_WithVirtualDtor() {}
+};
+
+void Create_InheritsFrom_WithVirtualDtor() {
+  InheritsFrom_WithVirtualDtor x;
+}
+
+
+// Make sure the dtor of InheritsFrom_WithVirtualDtor remains in the code,
+// i.e. we ignore -mconstructor-aliases when field paddings are added
+// because the paddings in InheritsFrom_WithVirtualDtor needs to be unpoisoned
+// in the dtor.
+// WITH_CTOR_ALIASES-LABEL: define void @_Z35Create_InheritsFrom_WithVirtualDtor
+// WITH_CTOR_ALIASES-NOT: call void @_ZN15WithVirtualDtorD2Ev
+// WITH_CTOR_ALIASES: call void @_ZN28InheritsFrom_WithVirtualDtorD2Ev
+// WITH_CTOR_ALIASES: ret void