[cfe-commits] r162254 - in /cfe/trunk: include/clang/AST/ASTContext.h lib/AST/ASTContext.cpp lib/CodeGen/CGExprAgg.cpp test/CodeGenObjCXX/implicit-copy-assign-operator.mm
John McCall
rjmccall at apple.com
Mon Aug 20 21:10:00 PDT 2012
Author: rjmccall
Date: Mon Aug 20 23:10:00 2012
New Revision: 162254
URL: http://llvm.org/viewvc/llvm-project?rev=162254&view=rev
Log:
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.
Modified:
cfe/trunk/include/clang/AST/ASTContext.h
cfe/trunk/lib/AST/ASTContext.cpp
cfe/trunk/lib/CodeGen/CGExprAgg.cpp
cfe/trunk/test/CodeGenObjCXX/implicit-copy-assign-operator.mm
Modified: cfe/trunk/include/clang/AST/ASTContext.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ASTContext.h?rev=162254&r1=162253&r2=162254&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/ASTContext.h (original)
+++ cfe/trunk/include/clang/AST/ASTContext.h Mon Aug 20 23:10:00 2012
@@ -1427,6 +1427,10 @@
/// characters. This method does not work on incomplete types.
CharUnits getTypeAlignInChars(QualType T) const;
CharUnits getTypeAlignInChars(const Type *T) const;
+
+ // getTypeInfoDataSizeInChars - Return the size of a type, in chars. If the
+ // type is a record, its data size is returned.
+ std::pair<CharUnits, CharUnits> getTypeInfoDataSizeInChars(QualType T) const;
std::pair<CharUnits, CharUnits> getTypeInfoInChars(const Type *T) const;
std::pair<CharUnits, CharUnits> getTypeInfoInChars(QualType T) const;
Modified: cfe/trunk/lib/AST/ASTContext.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=162254&r1=162253&r2=162254&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ASTContext.cpp (original)
+++ cfe/trunk/lib/AST/ASTContext.cpp Mon Aug 20 23:10:00 2012
@@ -1080,6 +1080,27 @@
return toCharUnitsFromBits(Align);
}
+// getTypeInfoDataSizeInChars - Return the size of a type, in
+// chars. If the type is a record, its data size is returned. This is
+// the size of the memcpy that's performed when assigning this type
+// using a trivial copy/move assignment operator.
+std::pair<CharUnits, CharUnits>
+ASTContext::getTypeInfoDataSizeInChars(QualType T) const {
+ std::pair<CharUnits, CharUnits> sizeAndAlign = getTypeInfoInChars(T);
+
+ // In C++, objects can sometimes be allocated into the tail padding
+ // of a base-class subobject. We decide whether that's possible
+ // during class layout, so here we can just trust the layout results.
+ if (getLangOpts().CPlusPlus) {
+ if (const RecordType *RT = T->getAs<RecordType>()) {
+ const ASTRecordLayout &layout = getASTRecordLayout(RT->getDecl());
+ sizeAndAlign.first = layout.getDataSize();
+ }
+ }
+
+ return sizeAndAlign;
+}
+
std::pair<CharUnits, CharUnits>
ASTContext::getTypeInfoInChars(const Type *T) const {
std::pair<uint64_t, unsigned> Info = getTypeInfo(T);
Modified: cfe/trunk/lib/CodeGen/CGExprAgg.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprAgg.cpp?rev=162254&r1=162253&r2=162254&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprAgg.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprAgg.cpp Mon Aug 20 23:10:00 2012
@@ -1300,9 +1300,9 @@
// implementation handles this case safely. If there is a libc that does not
// safely handle this, we can add a target hook.
- // Get size and alignment info for this aggregate.
+ // Get data size and alignment info for this aggregate.
std::pair<CharUnits, CharUnits> TypeInfo =
- getContext().getTypeInfoInChars(Ty);
+ getContext().getTypeInfoDataSizeInChars(Ty);
if (alignment.isZero())
alignment = TypeInfo.second;
Modified: cfe/trunk/test/CodeGenObjCXX/implicit-copy-assign-operator.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjCXX/implicit-copy-assign-operator.mm?rev=162254&r1=162253&r2=162254&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenObjCXX/implicit-copy-assign-operator.mm (original)
+++ cfe/trunk/test/CodeGenObjCXX/implicit-copy-assign-operator.mm Mon Aug 20 23:10:00 2012
@@ -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 @@
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;
+ };
+}
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