When performing a trivial copy of a C++ type, we must be careful not

to overwrite objects that might have been allocated into the type's
tail padding.  This patch is missing some potential optimizations where
the destination is provably a complete object, but it's necessary for
correctness.

Patch by Jonathan Sauer.

llvm-svn: 162254

1 files changed, 81 insertions, 14 deletions

diff --git a/clang/test/CodeGenObjCXX/implicit-copy-assign-operator.mm b/clang/test/CodeGenObjCXX/implicit-copy-assign-operator.mm
index 29ec9acd381..a5ce7896091 100644
--- a/clang/test/CodeGenObjCXX/implicit-copy-assign-operator.mm
+++ b/clang/test/CodeGenObjCXX/implicit-copy-assign-operator.mm
@@ -1,4 +1,6 @@
-// RUN: %clang_cc1 -fobjc-gc -emit-llvm -triple x86_64-apple-darwin10.0.0 -fobjc-runtime=macosx-fragile-10.5 -o - %s | FileCheck %s
+// RUN: %clang_cc1 -fobjc-gc -emit-llvm -triple x86_64-apple-darwin10.0.0 -fobjc-runtime=macosx-fragile-10.5 -o - %s | FileCheck %s -check-prefix=CHECK-OBJ
+// RUN: %clang_cc1 -x c++    -emit-llvm -triple x86_64-apple-darwin10.0.0                                    -o - %s | FileCheck %s -check-prefix=CHECK-CPP
+#ifdef __OBJC__
 struct A { 
   A &operator=(const A&);
   A &operator=(A&);
@@ -41,17 +43,82 @@ void test_D(D d1, D d2) {
   d1 = d2;
 }
 
-// CHECK: define linkonce_odr %struct.D* @_ZN1DaSERS_
-// CHECK: {{call.*_ZN1AaSERS_}}
-// CHECK: {{call.*_ZN1BaSERS_}}
-// CHECK: {{call.*_ZN1CaSERKS_}}
-// CHECK: {{call void @llvm.memcpy.p0i8.p0i8.i64.*i64 24}}
-// CHECK: {{call.*_ZN1BaSERS_}}
-// CHECK: br
-// CHECK: {{call.*_ZN1CaSERKS_}}
-// CHECK: {{call.*@objc_memmove_collectable}}
-// CHECK: {{call void @llvm.memcpy.p0i8.p0i8.i64.*i64 12}}
-// CHECK: call void @_ZN11CopyByValueC1ERKS_
-// CHECK: {{call.*_ZN11CopyByValueaSES_}}
-// CHECK: ret
+// CHECK-OBJ: define linkonce_odr %struct.D* @_ZN1DaSERS_
+// CHECK-OBJ: {{call.*_ZN1AaSERS_}}
+// CHECK-OBJ: {{call.*_ZN1BaSERS_}}
+// CHECK-OBJ: {{call.*_ZN1CaSERKS_}}
+// CHECK-OBJ: {{call void @llvm.memcpy.p0i8.p0i8.i64.*i64 24}}
+// CHECK-OBJ: {{call.*_ZN1BaSERS_}}
+// CHECK-OBJ: br
+// CHECK-OBJ: {{call.*_ZN1CaSERKS_}}
+// CHECK-OBJ: {{call.*@objc_memmove_collectable}}
+// CHECK-OBJ: {{call void @llvm.memcpy.p0i8.p0i8.i64.*i64 12}}
+// CHECK-OBJ: call void @_ZN11CopyByValueC1ERKS_
+// CHECK-OBJ: {{call.*_ZN11CopyByValueaSES_}}
+// CHECK-OBJ: ret
+#endif
 
+namespace PR13329 {
+#ifndef __OBJC__
+  typedef void* id;
+#endif
+  struct POD {
+    id    i;
+    short s;
+  };
+  
+  struct NonPOD {
+    id    i;
+    short s;
+    
+    NonPOD();
+  };
+  
+  struct DerivedNonPOD: NonPOD {
+    char  c;
+  };
+  
+  struct DerivedPOD: POD {
+    char  c;
+  };
+  
+  void testPOD() {
+    POD a;
+    POD b;
+    // CHECK-OBJ: @objc_memmove_collectable{{.*}}i64 16
+    // CHECK-CPP: @llvm.memcpy{{.*}}i64 16
+    b = a;
+  }
+  
+  void testNonPOD() {
+    NonPOD a;
+    NonPOD b;
+    // CHECK-OBJ: @objc_memmove_collectable{{.*}}i64 10
+    // CHECK-CPP: @llvm.memcpy{{.*}}i64 10
+    b = a;
+  }
+  
+  void testDerivedNonPOD() {
+    DerivedNonPOD a;
+    NonPOD        b;
+    DerivedNonPOD c;
+    // CHECK-OBJ: @objc_memmove_collectable{{.*}}i64 10
+    // CHECK-CPP: @llvm.memcpy{{.*}}i64 10
+    (NonPOD&) a = b;
+    // CHECK-OBJ: @objc_memmove_collectable{{.*}}i64 11
+    // CHECK-CPP: @llvm.memcpy{{.*}}i64 11
+    a = c;
+  };
+  
+  void testDerivedPOD() {
+    DerivedPOD a;
+    POD        b;
+    DerivedPOD c;
+    // CHECK-OBJ: @objc_memmove_collectable{{.*}}i64 16
+    // CHECK-CPP: @llvm.memcpy{{.*}}i64 16
+    (POD&) a = b;
+    // CHECK-OBJ: @objc_memmove_collectable{{.*}}i64 17
+    // CHECK-CPP: @llvm.memcpy{{.*}}i64 17
+    a = c;
+  };
+}