prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  apple clang does not have visibility "protected"
  This results in the attribute check function returning false on apple clang, but symbol visibility otherwise working.
  
  so something like:
  ```meson
  args = []
  if cc.has_function_attribute('visibility')
    args += '-DEXPORT=__attribute__((visibility("default")))
  endif
  
  library(
    'foo.c',
    c_args : args,
    gnu_symbol_visibility : 'hidden',
  )
  ```
  
  will fail with missing symbols because args is `[]`
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `mesonbuild/compilers/c_function_attributes.py`
  Content:
  ```
  1 # These functions are based on the following code:
  2 # https://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_gcc_func_attribute.m4,
  3 # which is licensed under the following terms:
  4 #
  5 #   Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>
  6 #
  7 #   Copying and distribution of this file, with or without modification, are
  8 #   permitted in any medium without royalty provided the copyright notice
  9 #   and this notice are preserved.  This file is offered as-is, without any
  10 #   warranty.
  11 #
  12 
  13 C_FUNC_ATTRIBUTES = {
  14     'alias': '''
  15         int foo(void) { return 0; }
  16         int bar(void) __attribute__((alias("foo")));''',
  17     'aligned':
  18         'int foo(void) __attribute__((aligned(32)));',
  19     'alloc_size':
  20         'void *foo(int a) __attribute__((alloc_size(1)));',
  21     'always_inline':
  22         'inline __attribute__((always_inline)) int foo(void) { return 0; }',
  23     'artificial':
  24         'inline __attribute__((artificial)) int foo(void) { return 0; }',
  25     'cold':
  26         'int foo(void) __attribute__((cold));',
  27     'const':
  28         'int foo(void) __attribute__((const));',
  29     'constructor':
  30         'int foo(void) __attribute__((constructor));',
  31     'constructor_priority':
  32         'int foo( void ) __attribute__((__constructor__(65535/2)));',
  33     'deprecated':
  34         'int foo(void) __attribute__((deprecated("")));',
  35     'destructor':
  36         'int foo(void) __attribute__((destructor));',
  37     'dllexport':
  38         '__declspec(dllexport) int foo(void) { return 0; }',
  39     'dllimport':
  40         '__declspec(dllimport) int foo(void);',
  41     'error':
  42         'int foo(void) __attribute__((error("")));',
  43     'externally_visible':
  44         'int foo(void) __attribute__((externally_visible));',
  45     'fallthrough': '''
  46         int foo( void ) {
  47           switch (0) {
  48             case 1: __attribute__((fallthrough));
  49             case 2: break;
  50           }
  51           return 0;
  52         };''',
  53     'flatten':
  54         'int foo(void) __attribute__((flatten));',
  55     'format':
  56         'int foo(const char * p, ...) __attribute__((format(printf, 1, 2)));',
  57     'format_arg':
  58         'char * foo(const char * p) __attribute__((format_arg(1)));',
  59     'gnu_inline':
  60         'inline __attribute__((gnu_inline)) int foo(void) { return 0; }',
  61     'hot':
  62         'int foo(void) __attribute__((hot));',
  63     'ifunc':
  64         ('int my_foo(void) { return 0; }'
  65          'static int (*resolve_foo(void))(void) { return my_foo; }'
  66          'int foo(void) __attribute__((ifunc("resolve_foo")));'),
  67     'leaf':
  68         '__attribute__((leaf)) int foo(void) { return 0; }',
  69     'malloc':
  70         'int *foo(void) __attribute__((malloc));',
  71     'noclone':
  72         'int foo(void) __attribute__((noclone));',
  73     'noinline':
  74         '__attribute__((noinline)) int foo(void) { return 0; }',
  75     'nonnull':
  76         'int foo(char * p) __attribute__((nonnull(1)));',
  77     'noreturn':
  78         'int foo(void) __attribute__((noreturn));',
  79     'nothrow':
  80         'int foo(void) __attribute__((nothrow));',
  81     'optimize':
  82         '__attribute__((optimize(3))) int foo(void) { return 0; }',
  83     'packed':
  84         'struct __attribute__((packed)) foo { int bar; };',
  85     'pure':
  86         'int foo(void) __attribute__((pure));',
  87     'returns_nonnull':
  88         'int *foo(void) __attribute__((returns_nonnull));',
  89     'unused':
  90         'int foo(void) __attribute__((unused));',
  91     'used':
  92         'int foo(void) __attribute__((used));',
  93     'visibility': '''
  94         int foo_def(void) __attribute__((visibility("default")));
  95         int foo_hid(void) __attribute__((visibility("hidden")));
  96         int foo_int(void) __attribute__((visibility("internal")));
  97         int foo_pro(void) __attribute__((visibility("protected")));''',
  98     'warning':
  99         'int foo(void) __attribute__((warning("")));',
  100     'warn_unused_result':
  101         'int foo(void) __attribute__((warn_unused_result));',
  102     'weak':
  103         'int foo(void) __attribute__((weak));',
  104     'weakref': '''
  105         static int foo(void) { return 0; }
  106         static int var(void) __attribute__((weakref("foo")));''',
  107 }
  108 
  109 CXX_FUNC_ATTRIBUTES = {
  110     # Alias must be applied to the mangled name in C++
  111     'alias':
  112         ('extern "C" {'
  113          'int foo(void) { return 0; }'
  114          '}'
  115          'int bar(void) __attribute__((alias("foo")));'
  116          ),
  117     'ifunc':
  118         ('extern "C" {'
  119          'int my_foo(void) { return 0; }'
  120          'static int (*resolve_foo(void))(void) { return my_foo; }'
  121          '}'
  122          'int foo(void) __attribute__((ifunc("resolve_foo")));'),
  123 }
  124
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/mesonbuild/compilers/c_function_attributes.py b/mesonbuild/compilers/c_function_attributes.py
  --- a/mesonbuild/compilers/c_function_attributes.py
  +++ b/mesonbuild/compilers/c_function_attributes.py
  @@ -93,8 +93,15 @@
       'visibility': '''
           int foo_def(void) __attribute__((visibility("default")));
           int foo_hid(void) __attribute__((visibility("hidden")));
  -        int foo_int(void) __attribute__((visibility("internal")));
  -        int foo_pro(void) __attribute__((visibility("protected")));''',
  +        int foo_int(void) __attribute__((visibility("internal")));''',
  +    'visibility:default':
  +        'int foo(void) __attribute__((visibility("default")));',
  +    'visibility:hidden':
  +        'int foo(void) __attribute__((visibility("hidden")));',
  +    'visibility:internal':
  +        'int foo(void) __attribute__((visibility("internal")));',
  +    'visibility:protected':
  +        'int foo(void) __attribute__((visibility("protected")));',
       'warning':
           'int foo(void) __attribute__((warning("")));',
       'warn_unused_result':
  
verification_info: {"golden_diff": "diff --git a/mesonbuild/compilers/c_function_attributes.py b/mesonbuild/compilers/c_function_attributes.py\n--- a/mesonbuild/compilers/c_function_attributes.py\n+++ b/mesonbuild/compilers/c_function_attributes.py\n@@ -93,8 +93,15 @@\n     'visibility': '''\n         int foo_def(void) __attribute__((visibility(\"default\")));\n         int foo_hid(void) __attribute__((visibility(\"hidden\")));\n-        int foo_int(void) __attribute__((visibility(\"internal\")));\n-        int foo_pro(void) __attribute__((visibility(\"protected\")));''',\n+        int foo_int(void) __attribute__((visibility(\"internal\")));''',\n+    'visibility:default':\n+        'int foo(void) __attribute__((visibility(\"default\")));',\n+    'visibility:hidden':\n+        'int foo(void) __attribute__((visibility(\"hidden\")));',\n+    'visibility:internal':\n+        'int foo(void) __attribute__((visibility(\"internal\")));',\n+    'visibility:protected':\n+        'int foo(void) __attribute__((visibility(\"protected\")));',\n     'warning':\n         'int foo(void) __attribute__((warning(\"\")));',\n     'warn_unused_result':\n", "issue": "apple clang does not have visibility \"protected\"\nThis results in the attribute check function returning false on apple clang, but symbol visibility otherwise working.\r\n\r\nso something like:\r\n```meson\r\nargs = []\r\nif cc.has_function_attribute('visibility')\r\n  args += '-DEXPORT=__attribute__((visibility(\"default\")))\r\nendif\r\n\r\nlibrary(\r\n  'foo.c',\r\n  c_args : args,\r\n  gnu_symbol_visibility : 'hidden',\r\n)\r\n```\r\n\r\nwill fail with missing symbols because args is `[]`\n", "before_files": [{"content": "# These functions are based on the following code:\n# https://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_gcc_func_attribute.m4,\n# which is licensed under the following terms:\n#\n#   Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>\n#\n#   Copying and distribution of this file, with or without modification, are\n#   permitted in any medium without royalty provided the copyright notice\n#   and this notice are preserved.  This file is offered as-is, without any\n#   warranty.\n#\n\nC_FUNC_ATTRIBUTES = {\n    'alias': '''\n        int foo(void) { return 0; }\n        int bar(void) __attribute__((alias(\"foo\")));''',\n    'aligned':\n        'int foo(void) __attribute__((aligned(32)));',\n    'alloc_size':\n        'void *foo(int a) __attribute__((alloc_size(1)));',\n    'always_inline':\n        'inline __attribute__((always_inline)) int foo(void) { return 0; }',\n    'artificial':\n        'inline __attribute__((artificial)) int foo(void) { return 0; }',\n    'cold':\n        'int foo(void) __attribute__((cold));',\n    'const':\n        'int foo(void) __attribute__((const));',\n    'constructor':\n        'int foo(void) __attribute__((constructor));',\n    'constructor_priority':\n        'int foo( void ) __attribute__((__constructor__(65535/2)));',\n    'deprecated':\n        'int foo(void) __attribute__((deprecated(\"\")));',\n    'destructor':\n        'int foo(void) __attribute__((destructor));',\n    'dllexport':\n        '__declspec(dllexport) int foo(void) { return 0; }',\n    'dllimport':\n        '__declspec(dllimport) int foo(void);',\n    'error':\n        'int foo(void) __attribute__((error(\"\")));',\n    'externally_visible':\n        'int foo(void) __attribute__((externally_visible));',\n    'fallthrough': '''\n        int foo( void ) {\n          switch (0) {\n            case 1: __attribute__((fallthrough));\n            case 2: break;\n          }\n          return 0;\n        };''',\n    'flatten':\n        'int foo(void) __attribute__((flatten));',\n    'format':\n        'int foo(const char * p, ...) __attribute__((format(printf, 1, 2)));',\n    'format_arg':\n        'char * foo(const char * p) __attribute__((format_arg(1)));',\n    'gnu_inline':\n        'inline __attribute__((gnu_inline)) int foo(void) { return 0; }',\n    'hot':\n        'int foo(void) __attribute__((hot));',\n    'ifunc':\n        ('int my_foo(void) { return 0; }'\n         'static int (*resolve_foo(void))(void) { return my_foo; }'\n         'int foo(void) __attribute__((ifunc(\"resolve_foo\")));'),\n    'leaf':\n        '__attribute__((leaf)) int foo(void) { return 0; }',\n    'malloc':\n        'int *foo(void) __attribute__((malloc));',\n    'noclone':\n        'int foo(void) __attribute__((noclone));',\n    'noinline':\n        '__attribute__((noinline)) int foo(void) { return 0; }',\n    'nonnull':\n        'int foo(char * p) __attribute__((nonnull(1)));',\n    'noreturn':\n        'int foo(void) __attribute__((noreturn));',\n    'nothrow':\n        'int foo(void) __attribute__((nothrow));',\n    'optimize':\n        '__attribute__((optimize(3))) int foo(void) { return 0; }',\n    'packed':\n        'struct __attribute__((packed)) foo { int bar; };',\n    'pure':\n        'int foo(void) __attribute__((pure));',\n    'returns_nonnull':\n        'int *foo(void) __attribute__((returns_nonnull));',\n    'unused':\n        'int foo(void) __attribute__((unused));',\n    'used':\n        'int foo(void) __attribute__((used));',\n    'visibility': '''\n        int foo_def(void) __attribute__((visibility(\"default\")));\n        int foo_hid(void) __attribute__((visibility(\"hidden\")));\n        int foo_int(void) __attribute__((visibility(\"internal\")));\n        int foo_pro(void) __attribute__((visibility(\"protected\")));''',\n    'warning':\n        'int foo(void) __attribute__((warning(\"\")));',\n    'warn_unused_result':\n        'int foo(void) __attribute__((warn_unused_result));',\n    'weak':\n        'int foo(void) __attribute__((weak));',\n    'weakref': '''\n        static int foo(void) { return 0; }\n        static int var(void) __attribute__((weakref(\"foo\")));''',\n}\n\nCXX_FUNC_ATTRIBUTES = {\n    # Alias must be applied to the mangled name in C++\n    'alias':\n        ('extern \"C\" {'\n         'int foo(void) { return 0; }'\n         '}'\n         'int bar(void) __attribute__((alias(\"foo\")));'\n         ),\n    'ifunc':\n        ('extern \"C\" {'\n         'int my_foo(void) { return 0; }'\n         'static int (*resolve_foo(void))(void) { return my_foo; }'\n         '}'\n         'int foo(void) __attribute__((ifunc(\"resolve_foo\")));'),\n}\n", "path": "mesonbuild/compilers/c_function_attributes.py"}], "after_files": [{"content": "# These functions are based on the following code:\n# https://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_gcc_func_attribute.m4,\n# which is licensed under the following terms:\n#\n#   Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>\n#\n#   Copying and distribution of this file, with or without modification, are\n#   permitted in any medium without royalty provided the copyright notice\n#   and this notice are preserved.  This file is offered as-is, without any\n#   warranty.\n#\n\nC_FUNC_ATTRIBUTES = {\n    'alias': '''\n        int foo(void) { return 0; }\n        int bar(void) __attribute__((alias(\"foo\")));''',\n    'aligned':\n        'int foo(void) __attribute__((aligned(32)));',\n    'alloc_size':\n        'void *foo(int a) __attribute__((alloc_size(1)));',\n    'always_inline':\n        'inline __attribute__((always_inline)) int foo(void) { return 0; }',\n    'artificial':\n        'inline __attribute__((artificial)) int foo(void) { return 0; }',\n    'cold':\n        'int foo(void) __attribute__((cold));',\n    'const':\n        'int foo(void) __attribute__((const));',\n    'constructor':\n        'int foo(void) __attribute__((constructor));',\n    'constructor_priority':\n        'int foo( void ) __attribute__((__constructor__(65535/2)));',\n    'deprecated':\n        'int foo(void) __attribute__((deprecated(\"\")));',\n    'destructor':\n        'int foo(void) __attribute__((destructor));',\n    'dllexport':\n        '__declspec(dllexport) int foo(void) { return 0; }',\n    'dllimport':\n        '__declspec(dllimport) int foo(void);',\n    'error':\n        'int foo(void) __attribute__((error(\"\")));',\n    'externally_visible':\n        'int foo(void) __attribute__((externally_visible));',\n    'fallthrough': '''\n        int foo( void ) {\n          switch (0) {\n            case 1: __attribute__((fallthrough));\n            case 2: break;\n          }\n          return 0;\n        };''',\n    'flatten':\n        'int foo(void) __attribute__((flatten));',\n    'format':\n        'int foo(const char * p, ...) __attribute__((format(printf, 1, 2)));',\n    'format_arg':\n        'char * foo(const char * p) __attribute__((format_arg(1)));',\n    'gnu_inline':\n        'inline __attribute__((gnu_inline)) int foo(void) { return 0; }',\n    'hot':\n        'int foo(void) __attribute__((hot));',\n    'ifunc':\n        ('int my_foo(void) { return 0; }'\n         'static int (*resolve_foo(void))(void) { return my_foo; }'\n         'int foo(void) __attribute__((ifunc(\"resolve_foo\")));'),\n    'leaf':\n        '__attribute__((leaf)) int foo(void) { return 0; }',\n    'malloc':\n        'int *foo(void) __attribute__((malloc));',\n    'noclone':\n        'int foo(void) __attribute__((noclone));',\n    'noinline':\n        '__attribute__((noinline)) int foo(void) { return 0; }',\n    'nonnull':\n        'int foo(char * p) __attribute__((nonnull(1)));',\n    'noreturn':\n        'int foo(void) __attribute__((noreturn));',\n    'nothrow':\n        'int foo(void) __attribute__((nothrow));',\n    'optimize':\n        '__attribute__((optimize(3))) int foo(void) { return 0; }',\n    'packed':\n        'struct __attribute__((packed)) foo { int bar; };',\n    'pure':\n        'int foo(void) __attribute__((pure));',\n    'returns_nonnull':\n        'int *foo(void) __attribute__((returns_nonnull));',\n    'unused':\n        'int foo(void) __attribute__((unused));',\n    'used':\n        'int foo(void) __attribute__((used));',\n    'visibility': '''\n        int foo_def(void) __attribute__((visibility(\"default\")));\n        int foo_hid(void) __attribute__((visibility(\"hidden\")));\n        int foo_int(void) __attribute__((visibility(\"internal\")));''',\n    'visibility:default':\n        'int foo(void) __attribute__((visibility(\"default\")));',\n    'visibility:hidden':\n        'int foo(void) __attribute__((visibility(\"hidden\")));',\n    'visibility:internal':\n        'int foo(void) __attribute__((visibility(\"internal\")));',\n    'visibility:protected':\n        'int foo(void) __attribute__((visibility(\"protected\")));',\n    'warning':\n        'int foo(void) __attribute__((warning(\"\")));',\n    'warn_unused_result':\n        'int foo(void) __attribute__((warn_unused_result));',\n    'weak':\n        'int foo(void) __attribute__((weak));',\n    'weakref': '''\n        static int foo(void) { return 0; }\n        static int var(void) __attribute__((weakref(\"foo\")));''',\n}\n\nCXX_FUNC_ATTRIBUTES = {\n    # Alias must be applied to the mangled name in C++\n    'alias':\n        ('extern \"C\" {'\n         'int foo(void) { return 0; }'\n         '}'\n         'int bar(void) __attribute__((alias(\"foo\")));'\n         ),\n    'ifunc':\n        ('extern \"C\" {'\n         'int my_foo(void) { return 0; }'\n         'static int (*resolve_foo(void))(void) { return my_foo; }'\n         '}'\n         'int foo(void) __attribute__((ifunc(\"resolve_foo\")));'),\n}\n", "path": "mesonbuild/compilers/c_function_attributes.py"}]}