[PATCH] No memcpy for copy ctor with -fsanitize-address-field-padding=1

[Kostya Serebryany]

Hi thakis,

When -fsanitize-address-field-padding=1 is present
don't emit memcpy for copy constructor.
Thanks Nico for the extra test case.

http://reviews.llvm.org/D6515

Files:
  lib/CodeGen/CGClass.cpp
  test/CodeGen/sanitize-address-field-padding.cpp

Index: lib/CodeGen/CGClass.cpp
===================================================================
--- lib/CodeGen/CGClass.cpp
+++ lib/CodeGen/CGClass.cpp
@@ -1735,7 +1735,7 @@
                                              bool Delegating, llvm::Value *This,
                                              const CXXConstructExpr *E) {
   // If this is a trivial constructor, just emit what's needed.
-  if (D->isTrivial()) {
+  if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding()) {
     if (E->getNumArgs() == 0) {
       // Trivial default constructor, no codegen required.
       assert(D->isDefaultConstructor() &&
@@ -1785,7 +1785,8 @@
 CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
                                         llvm::Value *This, llvm::Value *Src,
                                         const CXXConstructExpr *E) {
-  if (D->isTrivial()) {
+  if (D->isTrivial() &&
+      !D->getParent()->mayInsertExtraPadding()) {
     assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
     assert(D->isCopyOrMoveConstructor() &&
            "trivial 1-arg ctor not a copy/move ctor");
Index: test/CodeGen/sanitize-address-field-padding.cpp
===================================================================
--- test/CodeGen/sanitize-address-field-padding.cpp
+++ test/CodeGen/sanitize-address-field-padding.cpp
@@ -229,6 +229,7 @@
 
 void MakeTrivialCopy(ClassWithTrivialCopy *s1, ClassWithTrivialCopy *s2) {
   *s1 = *s2;
+  ClassWithTrivialCopy s3(*s2);
 }
 
 // CHECK-LABEL: define void @_Z15MakeTrivialCopyP20ClassWithTrivialCopyS0_

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