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| author | John McCall <rjmccall@apple.com> | 2012-09-25 10:10:39 +0000 |
|---|---|---|
| committer | John McCall <rjmccall@apple.com> | 2012-09-25 10:10:39 +0000 |
| commit | ecd03b447bb0e2ed1954c77441d49a4a17ca8138 (patch) | |
| tree | b634a656ca4ac8a9086c5afdc2443c25faaf9f80 /test/CodeGenCXX/delete.cpp | |
| parent | 0e33dcda5c0f642da737c00e65bcdea6b988ce0b (diff) | |
When performing a ::delete of an object with a virtual destructor,
be sure to delete the complete object pointer, not the original
pointer. This is necessary if the base being deleted is at a
non-zero offset in the complete object. This is only required
for objects with virtual destructors because deleting an object
via a base-class subobject when the base does not have a virtual
destructor is undefined behavior.
Noticed while reviewing the last four years of cxx-abi-dev
activity.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164597 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CodeGenCXX/delete.cpp')
| -rw-r--r-- | test/CodeGenCXX/delete.cpp | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/test/CodeGenCXX/delete.cpp b/test/CodeGenCXX/delete.cpp index 5a88f9f924..7a91ca8146 100644 --- a/test/CodeGenCXX/delete.cpp +++ b/test/CodeGenCXX/delete.cpp @@ -113,12 +113,23 @@ namespace test4 { // CHECK: define void @_ZN5test421global_delete_virtualEPNS_1XE void global_delete_virtual(X *xp) { - // CHECK: [[VTABLE:%.*]] = load void ([[X:%.*]])*** - // CHECK-NEXT: [[VFN:%.*]] = getelementptr inbounds void ([[X]])** [[VTABLE]], i64 0 - // CHECK-NEXT: [[VFNPTR:%.*]] = load void ([[X]])** [[VFN]] - // CHECK-NEXT: call void [[VFNPTR]]([[X]] [[OBJ:%.*]]) - // CHECK-NEXT: [[OBJVOID:%.*]] = bitcast [[X]] [[OBJ]] to i8* - // CHECK-NEXT: call void @_ZdlPv(i8* [[OBJVOID]]) nounwind + // Load the offset-to-top from the vtable and apply it. + // This has to be done first because the dtor can mess it up. + // CHECK: [[T0:%.*]] = bitcast [[X:%.*]]* [[XP:%.*]] to i64** + // CHECK-NEXT: [[VTABLE:%.*]] = load i64** [[T0]] + // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds i64* [[VTABLE]], i64 -2 + // CHECK-NEXT: [[OFFSET:%.*]] = load i64* [[T0]], align 8 + // CHECK-NEXT: [[T0:%.*]] = bitcast [[X]]* [[XP]] to i8* + // CHECK-NEXT: [[ALLOCATED:%.*]] = getelementptr inbounds i8* [[T0]], i64 [[OFFSET]] + // Load the complete-object destructor (not the deleting destructor) + // and call it. + // CHECK-NEXT: [[T0:%.*]] = bitcast [[X:%.*]]* [[XP:%.*]] to void ([[X]]*)*** + // CHECK-NEXT: [[VTABLE:%.*]] = load void ([[X]]*)*** [[T0]] + // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds void ([[X]]*)** [[VTABLE]], i64 0 + // CHECK-NEXT: [[DTOR:%.*]] = load void ([[X]]*)** [[T0]] + // CHECK-NEXT: call void [[DTOR]]([[X]]* [[OBJ:%.*]]) + // Call the global operator delete. + // CHECK-NEXT: call void @_ZdlPv(i8* [[ALLOCATED]]) nounwind ::delete xp; } } |