r221739 - [clang/asan] Do not emit memcpy for trivial operator= when -fsanitize-address-field-padding >= 1

[Kostya Serebryany]

Author: kcc
Date: Tue Nov 11 17:38:13 2014
New Revision: 221739

URL: http://llvm.org/viewvc/llvm-project?rev=221739&view=rev
Log:
[clang/asan] Do not emit memcpy for trivial operator= when -fsanitize-address-field-padding >= 1

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

Modified:
    cfe/trunk/lib/CodeGen/CGExprCXX.cpp
    cfe/trunk/test/CodeGen/sanitize-address-field-padding.cpp

Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=221739&r1=221738&r2=221739&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Tue Nov 11 17:38:13 2014
@@ -318,7 +318,7 @@ CodeGenFunction::EmitCXXOperatorMemberCa
   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);

Modified: cfe/trunk/test/CodeGen/sanitize-address-field-padding.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/sanitize-address-field-padding.cpp?rev=221739&r1=221738&r2=221739&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/sanitize-address-field-padding.cpp (original)
+++ cfe/trunk/test/CodeGen/sanitize-address-field-padding.cpp Tue Nov 11 17:38:13 2014
@@ -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