[libcxx-commits] [libcxx] [libc++] Remove potential 0-sized array in __compressed_pair_padding (PR #109028)
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libcxx-commits at lists.llvm.org
Mon Sep 30 00:03:56 PDT 2024
https://github.com/serge-sans-paille updated https://github.com/llvm/llvm-project/pull/109028
>From 1df4ef53007dd69e859cb3b9412a60ed3337c708 Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Tue, 17 Sep 2024 20:39:05 +0200
Subject: [PATCH 1/4] [libc++] Remove potential 0-sized array in
__compressed_pair_padding
---
libcxx/include/__memory/compressed_pair.h | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/libcxx/include/__memory/compressed_pair.h b/libcxx/include/__memory/compressed_pair.h
index 629e3ad8848ffa..77928af434f1f4 100644
--- a/libcxx/include/__memory/compressed_pair.h
+++ b/libcxx/include/__memory/compressed_pair.h
@@ -52,13 +52,16 @@ _LIBCPP_BEGIN_NAMESPACE_STD
#ifndef _LIBCPP_ABI_NO_COMPRESSED_PAIR_PADDING
-template <class _ToPad>
+template <class _ToPad,
+ bool _Empty = ((is_empty<_ToPad>::value && !__libcpp_is_final<_ToPad>::value) ||
+ is_reference<_ToPad>::value || sizeof(_ToPad) - __datasizeof_v<_ToPad> == 0)>
class __compressed_pair_padding {
- char __padding_[((is_empty<_ToPad>::value && !__libcpp_is_final<_ToPad>::value) || is_reference<_ToPad>::value)
- ? 0
- : sizeof(_ToPad) - __datasizeof_v<_ToPad>];
+ char __padding_[sizeof(_ToPad) - __datasizeof_v<_ToPad>];
};
+template <class _ToPad>
+class __compressed_pair_padding<_ToPad, true> {};
+
# define _LIBCPP_COMPRESSED_PAIR(T1, Initializer1, T2, Initializer2) \
_LIBCPP_NO_UNIQUE_ADDRESS __attribute__((__aligned__(_LIBCPP_ALIGNOF(T2)))) T1 Initializer1; \
_LIBCPP_NO_UNIQUE_ADDRESS ::std::__compressed_pair_padding<T1> _LIBCPP_CONCAT3(__padding1_, __LINE__, _); \
>From 55765d09969455128446310a1042c14bde95e227 Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Wed, 18 Sep 2024 11:25:18 +0200
Subject: [PATCH 2/4] [libc++] Remove potential 0-sized array in
__packed_format_arg_store
---
libcxx/include/__format/format_arg_store.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/libcxx/include/__format/format_arg_store.h b/libcxx/include/__format/format_arg_store.h
index 68e936acecade7..9a4a41df6d4e68 100644
--- a/libcxx/include/__format/format_arg_store.h
+++ b/libcxx/include/__format/format_arg_store.h
@@ -234,6 +234,11 @@ struct __packed_format_arg_store {
uint64_t __types_ = 0;
};
+template <class _Context>
+struct __packed_format_arg_store<_Context, 0> {
+ uint64_t __types_ = 0;
+};
+
template <class _Context, size_t _Np>
struct __unpacked_format_arg_store {
basic_format_arg<_Context> __args_[_Np];
>From 1112cfd95b9840fcf44f04cb73aedcf480146e4f Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Wed, 18 Sep 2024 16:51:50 +0200
Subject: [PATCH 3/4] fixup! [libc++] Remove potential 0-sized array in
__compressed_pair_padding
---
libcxx/include/__memory/compressed_pair.h | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/libcxx/include/__memory/compressed_pair.h b/libcxx/include/__memory/compressed_pair.h
index 77928af434f1f4..d955aebad63e31 100644
--- a/libcxx/include/__memory/compressed_pair.h
+++ b/libcxx/include/__memory/compressed_pair.h
@@ -52,15 +52,11 @@ _LIBCPP_BEGIN_NAMESPACE_STD
#ifndef _LIBCPP_ABI_NO_COMPRESSED_PAIR_PADDING
-template <class _ToPad,
- bool _Empty = ((is_empty<_ToPad>::value && !__libcpp_is_final<_ToPad>::value) ||
- is_reference<_ToPad>::value || sizeof(_ToPad) - __datasizeof_v<_ToPad> == 0)>
-class __compressed_pair_padding {
- char __padding_[sizeof(_ToPad) - __datasizeof_v<_ToPad>];
-};
-
template <class _ToPad>
-class __compressed_pair_padding<_ToPad, true> {};
+using __compressed_pair_padding =
+ __padding<((is_empty<_ToPad>::value && !__libcpp_is_final<_ToPad>::value) || is_reference<_ToPad>::value)
+ ? 0
+ : (sizeof(_ToPad) - __datasizeof_v<_ToPad>)>;
# define _LIBCPP_COMPRESSED_PAIR(T1, Initializer1, T2, Initializer2) \
_LIBCPP_NO_UNIQUE_ADDRESS __attribute__((__aligned__(_LIBCPP_ALIGNOF(T2)))) T1 Initializer1; \
>From 2269e8de5ff77462696284ca3d9572a056956901 Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Mon, 30 Sep 2024 09:03:21 +0200
Subject: [PATCH 4/4] fixup! fixup! [libc++] Remove potential 0-sized array in
__compressed_pair_padding
---
libcxx/include/CMakeLists.txt | 1 +
libcxx/include/__memory/compressed_pair.h | 1 +
libcxx/include/__memory/padding.h | 32 +++++++++++++++++++++++
libcxx/include/string | 9 +------
4 files changed, 35 insertions(+), 8 deletions(-)
create mode 100644 libcxx/include/__memory/padding.h
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 8c61009167ddce..d1f4e2acc705db 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -546,6 +546,7 @@ set(files
__memory/inout_ptr.h
__memory/noexcept_move_assign_container.h
__memory/out_ptr.h
+ __memory/padding.h
__memory/pointer_traits.h
__memory/ranges_construct_at.h
__memory/ranges_uninitialized_algorithms.h
diff --git a/libcxx/include/__memory/compressed_pair.h b/libcxx/include/__memory/compressed_pair.h
index d955aebad63e31..6717da0208e1c2 100644
--- a/libcxx/include/__memory/compressed_pair.h
+++ b/libcxx/include/__memory/compressed_pair.h
@@ -11,6 +11,7 @@
#define _LIBCPP___MEMORY_COMPRESSED_PAIR_H
#include <__config>
+#include <__memory/padding.h>
#include <__type_traits/datasizeof.h>
#include <__type_traits/is_empty.h>
#include <__type_traits/is_final.h>
diff --git a/libcxx/include/__memory/padding.h b/libcxx/include/__memory/padding.h
new file mode 100644
index 00000000000000..081bb4c6c7c281
--- /dev/null
+++ b/libcxx/include/__memory/padding.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_PADDING_H
+#define _LIBCPP___MEMORY_PADDING_H
+
+#include <__config>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <size_t _PaddingSize>
+struct __padding {
+ char __padding_[_PaddingSize];
+};
+
+template <>
+struct __padding<0> {};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_PADDING_H
diff --git a/libcxx/include/string b/libcxx/include/string
index fdb189016bfbac..781af5f1f27f48 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -610,6 +610,7 @@ basic_string<char32_t> operator""s( const char32_t *str, size_t len );
#include <__memory/compressed_pair.h>
#include <__memory/construct_at.h>
#include <__memory/noexcept_move_assign_container.h>
+#include <__memory/padding.h>
#include <__memory/pointer_traits.h>
#include <__memory/swap_allocator.h>
#include <__memory_resource/polymorphic_allocator.h>
@@ -749,14 +750,6 @@ struct __can_be_converted_to_string_view
struct __uninitialized_size_tag {};
struct __init_with_sentinel_tag {};
-template <size_t _PaddingSize>
-struct __padding {
- char __padding_[_PaddingSize];
-};
-
-template <>
-struct __padding<0> {};
-
template <class _CharT, class _Traits, class _Allocator>
class basic_string {
private:
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