[libcxx-commits] [libcxx] [Clang] Fix missing diagnostic for non-standard layout type in `offsetof` (PR #65246)
via libcxx-commits
libcxx-commits at lists.llvm.org
Sun Oct 1 17:57:17 PDT 2023
https://github.com/kasuga-fj updated https://github.com/llvm/llvm-project/pull/65246
>From 7d59f47b9b18ee5db90bb9fd69a1f73f68569ae4 Mon Sep 17 00:00:00 2001
From: "kasuga.ryotaro" <kasuga.ryotaro at fujitsu.com>
Date: Wed, 30 Aug 2023 13:26:31 +0900
Subject: [PATCH 01/10] [Clang] Fix missing diagnostic for non-standard layout
type in `offsetof`
Fixes #64619
Clang warns diagnostic for non-standard layout types in `offsetof` only
if they are in evaluated context. With this patch, you'll also get
diagnostic if you use `offsetof` on non-standard layout types in any
other contexts
---
clang/lib/Sema/SemaExpr.cpp | 9 ++++-----
clang/test/SemaCXX/class-layout.cpp | 30 ++++++++++++++---------------
clang/test/SemaCXX/ms_struct.cpp | 5 ++---
clang/test/SemaCXX/offsetof.cpp | 10 +++++-----
4 files changed, 26 insertions(+), 28 deletions(-)
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 92496b03ecabe54..6537b085aa46c5b 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -16766,12 +16766,11 @@ ExprResult Sema::BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
LangOpts.CPlusPlus11? diag::ext_offsetof_non_standardlayout_type
: diag::ext_offsetof_non_pod_type;
- if (!IsSafe && !DidWarnAboutNonPOD &&
- DiagRuntimeBehavior(BuiltinLoc, nullptr,
- PDiag(DiagID)
- << SourceRange(Components[0].LocStart, OC.LocEnd)
- << CurrentType))
+ if (!IsSafe && !DidWarnAboutNonPOD) {
+ Diag(BuiltinLoc, DiagID)
+ << SourceRange(Components[0].LocStart, OC.LocEnd) << CurrentType;
DidWarnAboutNonPOD = true;
+ }
}
// Look for the field.
diff --git a/clang/test/SemaCXX/class-layout.cpp b/clang/test/SemaCXX/class-layout.cpp
index 9782ff08100b2d6..23b3dbe24249378 100644
--- a/clang/test/SemaCXX/class-layout.cpp
+++ b/clang/test/SemaCXX/class-layout.cpp
@@ -1,18 +1,18 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-c++11-extensions
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
-// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
-// RUN: %clang_cc1 -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
-// RUN: %clang_cc1 -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=6 -DCLANG_ABI_COMPAT=6
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=14 -DCLANG_ABI_COMPAT=14
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=16 -DCLANG_ABI_COMPAT=16
-// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
-// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
-// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
-// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
-// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
-// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-invalid-offsetof -Wno-c++11-extensions
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
+// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=15
+// RUN: %clang_cc1 -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=6
+// RUN: %clang_cc1 -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=6
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=6 -DCLANG_ABI_COMPAT=6
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=14 -DCLANG_ABI_COMPAT=14
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=16 -DCLANG_ABI_COMPAT=16
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=15
+// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
+// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=15
+// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
+// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
+// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-c++11-extensions
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
diff --git a/clang/test/SemaCXX/ms_struct.cpp b/clang/test/SemaCXX/ms_struct.cpp
index e6f0a25b38ea80c..0d1a3d5259475d9 100644
--- a/clang/test/SemaCXX/ms_struct.cpp
+++ b/clang/test/SemaCXX/ms_struct.cpp
@@ -25,6 +25,7 @@ struct B : public A {
static_assert(__builtin_offsetof(B, d) == 12,
"We can't allocate the bitfield into the padding under ms_struct");
+// expected-warning at -2 {{offset of on non-standard-layout type 'B'}}
struct C {
#ifdef TEST_FOR_ERROR
@@ -38,6 +39,4 @@ struct C {
static_assert(__builtin_offsetof(C, n) == 8,
"long long field in ms_struct should be 8-byte aligned");
-#if !defined(TEST_FOR_ERROR) && !defined(TEST_FOR_WARNING)
-// expected-no-diagnostics
-#endif
+// expected-warning at -2 {{offset of on non-standard-layout type 'C'}}
\ No newline at end of file
diff --git a/clang/test/SemaCXX/offsetof.cpp b/clang/test/SemaCXX/offsetof.cpp
index c984657ebe1f0ed..a1e42d3d6802ff3 100644
--- a/clang/test/SemaCXX/offsetof.cpp
+++ b/clang/test/SemaCXX/offsetof.cpp
@@ -18,7 +18,7 @@ struct Base { int x; };
struct Derived : Base { int y; };
int o = __builtin_offsetof(Derived, x); // expected-warning{{offset of on non-POD type}}
-const int o2 = sizeof(__builtin_offsetof(Derived, x));
+const int o2 = sizeof(__builtin_offsetof(Derived, x)); // expected-warning{{offset of on non-POD type 'Derived'}}
struct HasArray {
int array[17];
@@ -51,9 +51,9 @@ struct Derived2 : public Base1, public Base2 {
int z;
};
-int derived1[__builtin_offsetof(Derived2, x) == 0? 1 : -1];
-int derived2[__builtin_offsetof(Derived2, y) == 4? 1 : -1];
-int derived3[__builtin_offsetof(Derived2, z) == 8? 1 : -1];
+int derived1[__builtin_offsetof(Derived2, x) == 0? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
+int derived2[__builtin_offsetof(Derived2, y) == 4? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
+int derived3[__builtin_offsetof(Derived2, z) == 8? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
// offsetof referring to anonymous struct in base.
// PR7769
@@ -66,7 +66,7 @@ struct foo {
struct bar : public foo {
};
-int anonstruct[__builtin_offsetof(bar, x) == 0 ? 1 : -1];
+int anonstruct[__builtin_offsetof(bar, x) == 0 ? 1 : -1]; // expected-warning{{offset of on non-POD type 'bar'}}
struct LtoRCheck {
int a[10];
>From e44041dc1ce0c9f75aba64560c8cfd5e1fe5ee88 Mon Sep 17 00:00:00 2001
From: "kasuga.ryotaro" <kasuga.ryotaro at fujitsu.com>
Date: Mon, 4 Sep 2023 16:06:56 +0900
Subject: [PATCH 02/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
---
clang/docs/ReleaseNotes.rst | 2 ++
1 file changed, 2 insertions(+)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8f5a67e14c9aba3..09497adbafb68d6 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -208,6 +208,8 @@ Improvements to Clang's diagnostics
(`#54678: <https://github.com/llvm/llvm-project/issues/54678>`_).
- Clang now prints its 'note' diagnostic in cyan instead of black, to be more compatible
with terminals with dark background colors. This is also more consistent with GCC.
+- Clang now always diagnoses when using non-standard layout types in ``offsetof`` .
+ (`#64619: <https://github.com/llvm/llvm-project/issues/64619>`_)
Bug Fixes in This Version
-------------------------
>From 8402bf31bc257b8b3521aeafab554177ed30e27a Mon Sep 17 00:00:00 2001
From: "kasuga.ryotaro" <kasuga.ryotaro at fujitsu.com>
Date: Mon, 4 Sep 2023 18:22:06 +0900
Subject: [PATCH 03/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
---
clang/test/SemaCXX/ms_struct.cpp | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/clang/test/SemaCXX/ms_struct.cpp b/clang/test/SemaCXX/ms_struct.cpp
index 0d1a3d5259475d9..995e424d1f87640 100644
--- a/clang/test/SemaCXX/ms_struct.cpp
+++ b/clang/test/SemaCXX/ms_struct.cpp
@@ -39,4 +39,5 @@ struct C {
static_assert(__builtin_offsetof(C, n) == 8,
"long long field in ms_struct should be 8-byte aligned");
-// expected-warning at -2 {{offset of on non-standard-layout type 'C'}}
\ No newline at end of file
+// expected-warning at -2 {{offset of on non-standard-layout type 'C'}}
+
>From b2dfb9f3c7aa681de631f3f33b19f470601bea49 Mon Sep 17 00:00:00 2001
From: "kasuga.ryotaro" <kasuga.ryotaro at fujitsu.com>
Date: Tue, 5 Sep 2023 13:39:12 +0900
Subject: [PATCH 05/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
---
clang/test/SemaCXX/offsetof.cpp | 1 +
1 file changed, 1 insertion(+)
diff --git a/clang/test/SemaCXX/offsetof.cpp b/clang/test/SemaCXX/offsetof.cpp
index a1e42d3d6802ff3..bf8a064859915b8 100644
--- a/clang/test/SemaCXX/offsetof.cpp
+++ b/clang/test/SemaCXX/offsetof.cpp
@@ -68,6 +68,7 @@ struct bar : public foo {
int anonstruct[__builtin_offsetof(bar, x) == 0 ? 1 : -1]; // expected-warning{{offset of on non-POD type 'bar'}}
+
struct LtoRCheck {
int a[10];
int f();
>From 894b3f96d3fa9ec20e2c8e1f23914f521cde51a0 Mon Sep 17 00:00:00 2001
From: "kasuga.ryotaro" <kasuga.ryotaro at fujitsu.com>
Date: Wed, 6 Sep 2023 10:23:56 +0900
Subject: [PATCH 06/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
---
clang/lib/Sema/SemaExpr.cpp | 2 +-
clang/test/SemaCXX/offsetof.cpp | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 6537b085aa46c5b..fedea932c5e15fe 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -16766,7 +16766,7 @@ ExprResult Sema::BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
LangOpts.CPlusPlus11? diag::ext_offsetof_non_standardlayout_type
: diag::ext_offsetof_non_pod_type;
- if (!IsSafe && !DidWarnAboutNonPOD) {
+ if (!IsSafe && !DidWarnAboutNonPOD && !isUnevaluatedContext()) {
Diag(BuiltinLoc, DiagID)
<< SourceRange(Components[0].LocStart, OC.LocEnd) << CurrentType;
DidWarnAboutNonPOD = true;
diff --git a/clang/test/SemaCXX/offsetof.cpp b/clang/test/SemaCXX/offsetof.cpp
index bf8a064859915b8..c4e86369f007dcb 100644
--- a/clang/test/SemaCXX/offsetof.cpp
+++ b/clang/test/SemaCXX/offsetof.cpp
@@ -18,7 +18,7 @@ struct Base { int x; };
struct Derived : Base { int y; };
int o = __builtin_offsetof(Derived, x); // expected-warning{{offset of on non-POD type}}
-const int o2 = sizeof(__builtin_offsetof(Derived, x)); // expected-warning{{offset of on non-POD type 'Derived'}}
+const int o2 = sizeof(__builtin_offsetof(Derived, x));
struct HasArray {
int array[17];
>From 67df2b7ba361cc724a70d8f8b140abbc27bc8e24 Mon Sep 17 00:00:00 2001
From: kasuga-fj <kasuga.ryotaro at fujitsu.com>
Date: Thu, 28 Sep 2023 18:10:15 +0900
Subject: [PATCH 07/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
---
libcxx/include/__type_traits/datasizeof.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/libcxx/include/__type_traits/datasizeof.h b/libcxx/include/__type_traits/datasizeof.h
index 019099a9cf183b5..88a702470c3c15a 100644
--- a/libcxx/include/__type_traits/datasizeof.h
+++ b/libcxx/include/__type_traits/datasizeof.h
@@ -47,7 +47,11 @@ struct __libcpp_datasizeof {
};
#endif
+ _LIBCPP_DIAGNOSTIC_PUSH
+ _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
+ _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
static const size_t value = offsetof(_FirstPaddingByte<>, __first_padding_byte_);
+ _LIBCPP_DIAGNOSTIC_POP
};
_LIBCPP_END_NAMESPACE_STD
>From bf479bc77e927aaa7a90c765987020ad39c857a5 Mon Sep 17 00:00:00 2001
From: kasuga-fj <kasuga.ryotaro at fujitsu.com>
Date: Fri, 29 Sep 2023 13:04:08 +0900
Subject: [PATCH 08/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
---
libcxx/include/__type_traits/datasizeof.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/libcxx/include/__type_traits/datasizeof.h b/libcxx/include/__type_traits/datasizeof.h
index 88a702470c3c15a..a28be0e94e5b7ac 100644
--- a/libcxx/include/__type_traits/datasizeof.h
+++ b/libcxx/include/__type_traits/datasizeof.h
@@ -47,6 +47,8 @@ struct __libcpp_datasizeof {
};
#endif
+ // Disable warnings related to the use of `offsetof` on non-standard layout or non-POD types
+ // TODO : Find a way to replace `offsetof` ?
_LIBCPP_DIAGNOSTIC_PUSH
_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
>From b9e201a80ee7e79f8ddfe37fee097b8efddc0a8a Mon Sep 17 00:00:00 2001
From: kasuga-fj <143047127+kasuga-fj at users.noreply.github.com>
Date: Mon, 2 Oct 2023 09:52:37 +0900
Subject: [PATCH 09/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
Co-authored-by: philnik777 <nikolasklauser at berlin.de>
---
libcxx/include/__type_traits/datasizeof.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libcxx/include/__type_traits/datasizeof.h b/libcxx/include/__type_traits/datasizeof.h
index a28be0e94e5b7ac..cfdd8cbbcb982b1 100644
--- a/libcxx/include/__type_traits/datasizeof.h
+++ b/libcxx/include/__type_traits/datasizeof.h
@@ -47,7 +47,7 @@ struct __libcpp_datasizeof {
};
#endif
- // Disable warnings related to the use of `offsetof` on non-standard layout or non-POD types
+ // _FirstPaddingByte<> is sometimes non-standard layout. Using `offsetof` is UB in that case, but GCC and Clang allow the use as an extension.
// TODO : Find a way to replace `offsetof` ?
_LIBCPP_DIAGNOSTIC_PUSH
_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
>From bceac70fb5514d1c3583e690ec1b2bc3b2ee039c Mon Sep 17 00:00:00 2001
From: kasuga-fj <kasuga.ryotaro at fujitsu.com>
Date: Mon, 2 Oct 2023 09:56:55 +0900
Subject: [PATCH 10/10] fixup! [Clang] Fix missing diagnostic for non-standard
layout type in `offsetof`
---
libcxx/include/__type_traits/datasizeof.h | 2 --
1 file changed, 2 deletions(-)
diff --git a/libcxx/include/__type_traits/datasizeof.h b/libcxx/include/__type_traits/datasizeof.h
index cfdd8cbbcb982b1..8795bd7a7c57a86 100644
--- a/libcxx/include/__type_traits/datasizeof.h
+++ b/libcxx/include/__type_traits/datasizeof.h
@@ -48,10 +48,8 @@ struct __libcpp_datasizeof {
#endif
// _FirstPaddingByte<> is sometimes non-standard layout. Using `offsetof` is UB in that case, but GCC and Clang allow the use as an extension.
- // TODO : Find a way to replace `offsetof` ?
_LIBCPP_DIAGNOSTIC_PUSH
_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
- _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
static const size_t value = offsetof(_FirstPaddingByte<>, __first_padding_byte_);
_LIBCPP_DIAGNOSTIC_POP
};
More information about the libcxx-commits
mailing list