It's fairly common on Linux and *BSD platforms to check for these attributes existence, so it makes sense to me to have this checking build into meson itself. Autotools also has a builtin for handling these, and by building them in we can short circuit cases that we know that these don't exist (MSVC). Additionally this adds support for two common MSVC __declspec attributes, dllimport and dllexport. This implements the declspec version (even though GCC has an __attribute__ version that both it and clang support), since GCC and Clang support the MSVC version as well. Thus it seems reasonable to assume that most projects will use the __declspec version over teh __attribute__ version.pull/3986/head
Dylan Baker
8 years ago
committed by
Nirbheek Chauhan
parent
8ca463f9f1
commit
51e9db370a
9 changed files with 388 additions and 1 deletions
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## Helper methods added for checking GNU style attributes: __attribute__(...) |
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|
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A set of new helpers have been added to the C and C++ compiler objects for |
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checking GNU style function attributes. These are not just simpler to use, they |
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may be optimized to return fast on compilers that don't support these |
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attributes. Currently this is true for MSVC. |
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|
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```meson |
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cc = meson.get_compiler('c') |
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if cc.has_function_attribute('aligned') |
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add_project_arguments('-DHAVE_ALIGNED', language : 'c') |
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endif |
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``` |
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|
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Would replace code like: |
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|
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```meson |
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if cc.compiles('''into foo(void) __attribute__((aligned(32)))''') |
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add_project_arguments('-DHAVE_ALIGNED', language : 'c') |
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endif |
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``` |
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|
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Additionally, a multi argument version has been added: |
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|
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```meson |
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foreach s : cc.get_supported_function_attributes(['hidden', 'alias']) |
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add_project_arguments('-DHAVE_@0@'.format(s.to_upper()), language : 'c') |
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endforeach |
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``` |
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@ -0,0 +1,123 @@ |
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# These functions are based on the following code: |
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# https://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_gcc_func_attribute.m4, |
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# which is licensed under the following terms: |
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# |
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# Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com> |
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# |
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# Copying and distribution of this file, with or without modification, are |
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# permitted in any medium without royalty provided the copyright notice |
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# and this notice are preserved. This file is offered as-is, without any |
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# warranty. |
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# |
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|
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C_FUNC_ATTRIBUTES = { |
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'alias': ''' |
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int foo(void) { return 0; } |
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int bar(void) __attribute__((alias("foo")));''', |
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'aligned': |
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'int foo(void) __attribute__((aligned(32)));', |
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'alloc_size': |
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'void *foo(int a) __attribute__((alloc_size(1)));', |
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'always_inline': |
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'inline __attribute__((always_inline)) int foo(void) { return 0; }', |
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'artificial': |
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'inline __attribute__((artificial)) int foo(void) { return 0; }', |
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'cold': |
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'int foo(void) __attribute__((cold));', |
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'const': |
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'int foo(void) __attribute__((const));', |
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'constructor': |
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'int foo(void) __attribute__((constructor));', |
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'constructor_priority': |
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'int foo( void ) __attribute__((__constructor__(65535/2)));', |
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'deprecated': |
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'int foo(void) __attribute__((deprecated("")));', |
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'destructor': |
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'int foo(void) __attribute__((destructor));', |
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'dllexport': |
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'__declspec(dllexport) int foo(void) { return 0; }', |
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'dllimport': |
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'__declspec(dllimport) int foo(void);', |
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'error': |
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'int foo(void) __attribute__((error("")));', |
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'externally_visible': |
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'int foo(void) __attribute__((externally_visible));', |
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'fallthrough': ''' |
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int foo( void ) { |
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switch (0) { |
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case 1: __attribute__((fallthrough)); |
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case 2: break; |
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} |
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return 0; |
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};''', |
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'flatten': |
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'int foo(void) __attribute__((flatten));', |
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'format': |
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'int foo(const char * p, ...) __attribute__((format(printf, 1, 2)));', |
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'format_arg': |
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'char * foo(const char * p) __attribute__((format_arg(1)));', |
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'gnu_inline': |
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'inline __attribute__((gnu_inline)) int foo(void) { return 0; }', |
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'hot': |
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'int foo(void) __attribute__((hot));', |
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'ifunc': |
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('int my_foo(void) { return 0; }' |
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'static int (*resolve_foo(void))(void) { return my_foo; }' |
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'int foo(void) __attribute__((ifunc("resolve_foo")));'), |
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'leaf': |
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'__attribute__((leaf)) int foo(void) { return 0; }', |
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'malloc': |
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'int *foo(void) __attribute__((malloc));', |
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'noclone': |
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'int foo(void) __attribute__((noclone));', |
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'noinline': |
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'__attribute__((noinline)) int foo(void) { return 0; }', |
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'nonnull': |
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'int foo(char * p) __attribute__((nonnull(1)));', |
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'noreturn': |
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'int foo(void) __attribute__((noreturn));', |
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'nothrow': |
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'int foo(void) __attribute__((nothrow));', |
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'optimize': |
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'__attribute__((optimize(3))) int foo(void) { return 0; }', |
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'packed': |
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'struct __attribute__((packed)) foo { int bar; };', |
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'pure': |
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'int foo(void) __attribute__((pure));', |
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'returns_nonnull': |
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'int *foo(void) __attribute__((returns_nonnull));', |
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'unused': |
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'int foo(void) __attribute__((unused));', |
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'used': |
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'int foo(void) __attribute__((used));', |
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'visibility': ''' |
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int foo_def(void) __attribute__((visibility(("default")))); |
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int foo_hid(void) __attribute__((visibility(("hidden")))); |
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int foo_int(void) __attribute__((visibility(("internal")))); |
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int foo_pro(void) __attribute__((visibility(("protected"))));''', |
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'warning': |
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'int foo(void) __attribute__((warning("")));', |
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'warn_unused_result': |
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'int foo(void) __attribute__((warn_unused_result));', |
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'weak': |
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'int foo(void) __attribute__((weak));', |
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'weakref': ''' |
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static int foo(void) { return 0; } |
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static int var(void) __attribute__((weakref("foo")));''', |
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} |
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|
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CXX_FUNC_ATTRIBUTES = { |
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# Alias must be applied to the mangled name in C++ |
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'alias': |
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('extern "C" {' |
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'int foo(void) { return 0; }' |
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'}' |
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'int bar(void) __attribute__((alias("foo")));' |
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), |
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'ifunc': |
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('extern "C" {' |
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'int my_foo(void) { return 0; }' |
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'static int (*resolve_foo(void))(void) { return my_foo; }' |
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'}' |
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'int foo(void) __attribute__((ifunc("resolve_foo")));'), |
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} |
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@ -0,0 +1,103 @@ |
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# Copyright © 2017-2018 Intel Corporation |
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# |
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# Licensed under the Apache License, Version 2.0 (the "License"); |
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# you may not use this file except in compliance with the License. |
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# You may obtain a copy of the License at |
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# |
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# http://www.apache.org/licenses/LICENSE-2.0 |
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# |
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# Unless required by applicable law or agreed to in writing, software |
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# distributed under the License is distributed on an "AS IS" BASIS, |
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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# See the License for the specific language governing permissions and |
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# limitations under the License. |
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project('gcc func attributes', ['c', 'cpp']) |
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# For msvc these will fail because msvc doesn't support __attribute__, for |
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# Clang and GCC, they should pass. |
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c = meson.get_compiler('c') |
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cpp = meson.get_compiler('cpp') |
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expected_result = c.get_id() != 'msvc' |
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# Q: Why is ifunc not in this list or any of the below lists? |
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# A: It's too damn hard to figure out if you actually support it, since it |
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# requires both compiler and libc support, and there isn't a good way to |
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# figure that out except by running the code we're trying to test. |
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attributes = [ |
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'aligned', |
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'alloc_size', |
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'always_inline', |
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'cold', |
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'const', |
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'constructor', |
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'constructor_priority', |
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'deprecated', |
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'destructor', |
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'flatten', |
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'format', |
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'format_arg', |
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'gnu_inline', |
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'hot', |
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'malloc', |
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'noinline', |
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'nonnull', |
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'noreturn', |
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'nothrow', |
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'pure', |
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'unused', |
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'used', |
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'warn_unused_result', |
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'weak', |
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'weakref', |
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] |
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|
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# These are unsupported on darwin with apple clang 9.1.0 |
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if host_machine.system() != 'darwin' |
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attributes += 'alias' |
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attributes += 'visibility' |
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endif |
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|
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if c.get_id() == 'gcc' |
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# not supported by clang as of 5.0.0 (at least up to 6.0.1) |
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attributes += 'artificial' |
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attributes += 'error' |
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attributes += 'externally_visible' |
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attributes += 'leaf' |
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attributes += 'noclone' |
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attributes += 'optimize' |
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attributes += 'warning' |
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if c.version().version_compare('>= 7.0.0') |
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attributes += 'fallthrough' |
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endif |
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endif |
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foreach a : attributes |
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x = c.has_function_attribute(a) |
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assert(x == expected_result, '@0@: @1@'.format(c.get_id(), a)) |
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x = cpp.has_function_attribute(a) |
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assert(x == expected_result, '@0@: @1@'.format(cpp.get_id(), a)) |
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endforeach |
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|
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win_expect = ['windows', 'cygwin'].contains(host_machine.system()) |
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foreach a : ['dllexport', 'dllimport'] |
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assert(c.has_function_attribute(a) == win_expect, |
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'@0@: @1@'.format(c.get_id(), a)) |
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assert(cpp.has_function_attribute(a) == win_expect, |
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'@0@: @1@'.format(cpp.get_id(), a)) |
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endforeach |
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|
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message('checking get_supported_function_attributes') |
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if c.get_id() != 'msvc' |
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multi_expected = attributes |
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else |
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multi_expected = [] |
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endif |
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multi_check = c.get_supported_function_attributes(attributes) |
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assert(multi_check == multi_expected, 'get_supported_function_arguments works (C)') |
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multi_check = cpp.get_supported_function_attributes(attributes) |
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assert(multi_check == multi_expected, 'get_supported_function_arguments works (C++)') |
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