[clang/asan] Do not emit memcpy for trivial operator= when -fsanitize-address-field...

Summary: If we've added poisoned paddings to a type do not emit memcpy for operator=.

Test Plan: regression tests.

Reviewers: majnemer, rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D6160

llvm-svn: 221739

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 3d1283f..39c77eb 100644 (file)
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -318,7 +318,7 @@ CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
   llvm::Value *This = LV.getAddress();
 
   if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
-      MD->isTrivial()) {
+      MD->isTrivial() && !MD->getParent()->mayInsertExtraPadding()) {
     llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress();
     QualType Ty = E->getType();
     EmitAggregateAssign(This, Src, Ty);

diff --git a/clang/test/CodeGen/sanitize-address-field-padding.cpp b/clang/test/CodeGen/sanitize-address-field-padding.cpp
index 9066a5e..0683089 100644 (file)
--- a/clang/test/CodeGen/sanitize-address-field-padding.cpp
+++ b/clang/test/CodeGen/sanitize-address-field-padding.cpp
@@ -217,3 +217,20 @@ void Create_InheritsFrom_WithVirtualDtor() {
 // WITH_CTOR_ALIASES-NOT: call void @_ZN15WithVirtualDtorD2Ev
 // WITH_CTOR_ALIASES: call void @_ZN28InheritsFrom_WithVirtualDtorD2Ev
 // WITH_CTOR_ALIASES: ret void
+
+// Make sure we don't emit memcpy for operator= if paddings are inserted.
+struct ClassWithTrivialCopy {
+  ClassWithTrivialCopy();
+  ~ClassWithTrivialCopy();
+  void *a;
+ private:
+  void *c;
+};
+
+void MakeTrivialCopy(ClassWithTrivialCopy *s1, ClassWithTrivialCopy *s2) {
+  *s1 = *s2;
+}
+
+// CHECK-LABEL: define void @_Z15MakeTrivialCopyP20ClassWithTrivialCopyS0_
+// CHECK-NOT: memcpy
+// CHECK: ret void