1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___CONFIGURATION_ABI_H
11#define _LIBCPP___CONFIGURATION_ABI_H
12
13#include <__config_site>
14#include <__configuration/compiler.h>
15#include <__configuration/platform.h>
16
17#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
18# pragma GCC system_header
19#endif
20
21// FIXME: ABI detection should be done via compiler builtin macros. This
22// is just a placeholder until Clang implements such macros. For now assume
23// that Windows compilers pretending to be MSVC++ target the Microsoft ABI,
24// and allow the user to explicitly specify the ABI to handle cases where this
25// heuristic falls short.
26#if _LIBCPP_ABI_FORCE_ITANIUM && _LIBCPP_ABI_FORCE_MICROSOFT
27# error "Only one of _LIBCPP_ABI_FORCE_ITANIUM and _LIBCPP_ABI_FORCE_MICROSOFT can be true"
28#elif _LIBCPP_ABI_FORCE_ITANIUM
29# define _LIBCPP_ABI_ITANIUM
30#elif _LIBCPP_ABI_FORCE_MICROSOFT
31# define _LIBCPP_ABI_MICROSOFT
32#else
33# if defined(_WIN32) && defined(_MSC_VER)
34# define _LIBCPP_ABI_MICROSOFT
35# else
36# define _LIBCPP_ABI_ITANIUM
37# endif
38#endif
39
40#if _LIBCPP_ABI_VERSION >= 2
41// TODO: Move the description of the remaining ABI flags to ABIGuarantees.rst or remove them.
42
43// Override the default return value of exception::what() for bad_function_call::what()
44// with a string that is specific to bad_function_call (see http://wg21.link/LWG2233).
45// This is an ABI break on platforms that sign and authenticate vtable function pointers
46// because it changes the mangling of the virtual function located in the vtable, which
47// changes how it gets signed.
48# define _LIBCPP_ABI_BAD_FUNCTION_CALL_GOOD_WHAT_MESSAGE
49// According to the Standard, `bitset::operator[] const` returns bool
50# define _LIBCPP_ABI_BITSET_VECTOR_BOOL_CONST_SUBSCRIPT_RETURN_BOOL
51
52// In LLVM 20, we've changed to take these ABI breaks unconditionally. These flags only exist in case someone is running
53// into the static_asserts we added to catch the ABI break and don't care that it is one.
54// TODO(LLVM 22): Remove these flags
55# define _LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB
56# define _LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB
57# define _LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB
58# define _LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB
59
60// These flags are documented in ABIGuarantees.rst
61# define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
62# define _LIBCPP_ABI_DO_NOT_EXPORT_BASIC_STRING_COMMON
63# define _LIBCPP_ABI_DO_NOT_EXPORT_VECTOR_BASE_COMMON
64# define _LIBCPP_ABI_DO_NOT_EXPORT_TO_CHARS_BASE_10
65# define _LIBCPP_ABI_ENABLE_SHARED_PTR_TRIVIAL_ABI
66# define _LIBCPP_ABI_ENABLE_UNIQUE_PTR_TRIVIAL_ABI
67# define _LIBCPP_ABI_FIX_CITYHASH_IMPLEMENTATION
68# define _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
69# define _LIBCPP_ABI_INCOMPLETE_TYPES_IN_DEQUE
70# define _LIBCPP_ABI_IOS_ALLOW_ARBITRARY_FILL_VALUE
71# define _LIBCPP_ABI_NO_COMPRESSED_PAIR_PADDING
72# define _LIBCPP_ABI_NO_FILESYSTEM_INLINE_NAMESPACE
73# define _LIBCPP_ABI_NO_ITERATOR_BASES
74# define _LIBCPP_ABI_NO_RANDOM_DEVICE_COMPATIBILITY_LAYOUT
75# define _LIBCPP_ABI_OPTIMIZED_FUNCTION
76# define _LIBCPP_ABI_REGEX_CONSTANTS_NONZERO
77# define _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
78# define _LIBCPP_ABI_USE_WRAP_ITER_IN_STD_ARRAY
79# define _LIBCPP_ABI_USE_WRAP_ITER_IN_STD_STRING_VIEW
80# define _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
81
82#elif _LIBCPP_ABI_VERSION == 1
83# if !(defined(_LIBCPP_OBJECT_FORMAT_COFF) || defined(_LIBCPP_OBJECT_FORMAT_XCOFF))
84// Enable compiling copies of now inline methods into the dylib to support
85// applications compiled against older libraries. This is unnecessary with
86// COFF dllexport semantics, since dllexport forces a non-inline definition
87// of inline functions to be emitted anyway. Our own non-inline copy would
88// conflict with the dllexport-emitted copy, so we disable it. For XCOFF,
89// the linker will take issue with the symbols in the shared object if the
90// weak inline methods get visibility (such as from -fvisibility-inlines-hidden),
91// so disable it.
92# define _LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS
93# endif
94// Feature macros for disabling pre ABI v1 features. All of these options
95// are deprecated.
96# if defined(__FreeBSD__)
97# define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
98# endif
99#endif
100
101// We had some bugs where we use [[no_unique_address]] together with construct_at,
102// which causes UB as the call on construct_at could write to overlapping subobjects
103//
104// https://github.com/llvm/llvm-project/issues/70506
105// https://github.com/llvm/llvm-project/issues/70494
106//
107// To fix the bug we had to change the ABI of some classes to remove [[no_unique_address]] under certain conditions.
108// The macro below is used for all classes whose ABI have changed as part of fixing these bugs.
109#define _LIBCPP_ABI_LLVM18_NO_UNIQUE_ADDRESS __attribute__((__abi_tag__("llvm18_nua")))
110
111// [[msvc::no_unique_address]] seems to mostly affect empty classes, so the padding scheme for Itanium doesn't work.
112#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_ABI_NO_COMPRESSED_PAIR_PADDING)
113# define _LIBCPP_ABI_NO_COMPRESSED_PAIR_PADDING
114#endif
115
116// Tracks the bounds of the array owned by std::unique_ptr<T[]>, allowing it to trap when accessed out-of-bounds.
117// Note that limited bounds checking is also available outside of this ABI configuration, but only some categories
118// of types can be checked.
119//
120// ABI impact: This causes the layout of std::unique_ptr<T[]> to change and its size to increase.
121// This also affects the representation of a few library types that use std::unique_ptr
122// internally, such as the unordered containers.
123// #define _LIBCPP_ABI_BOUNDED_UNIQUE_PTR
124
125#if defined(_LIBCPP_COMPILER_CLANG_BASED)
126# if defined(__APPLE__)
127# if defined(__i386__) || defined(__x86_64__)
128// use old string layout on x86_64 and i386
129# elif defined(__arm__)
130// use old string layout on arm (which does not include aarch64/arm64), except on watch ABIs
131# if defined(__ARM_ARCH_7K__) && __ARM_ARCH_7K__ >= 2
132# define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
133# endif
134# else
135# define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
136# endif
137# endif
138#endif
139
140#endif // _LIBCPP___CONFIGURATION_ABI_H
141