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| author | Nirbheek Chauhan <nirbheek@centricular.com> | 2018-06-03 16:57:29 +0530 |
|---|---|---|
| committer | Nirbheek Chauhan <nirbheek@centricular.com> | 2018-06-03 18:40:20 +0530 |
| commit | 3713c97ce9c1718fc25cf43cb6989c3a6118e3be (patch) | |
| tree | 12490926b1d65827106d8c560032834f8f9fd545 | |
| parent | 9e7b0dd70430cf0aa71869c46342cb908e99274f (diff) | |
| download | meson-3713c97ce9c1718fc25cf43cb6989c3a6118e3be.tar.gz | |
has_function: Improve built-in detection with headers
* __has_builtin(foo) is more correct and more reliable than
__has_builtin(__builtin_foo)
* If detection of built-ins with headers fails in the first check
because we can't take the address of a built-in, we can do an
ordinary check.
We can't always do this ordinary check because clang on macOS ld
removes the symbol when using -Wl,-no_weak_imports, which is needed
for being able to target the correct platform with XCode 8 and newer.
Closes https://github.com/mesonbuild/meson/issues/3672
| -rw-r--r-- | mesonbuild/compilers/c.py | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/mesonbuild/compilers/c.py b/mesonbuild/compilers/c.py index 4cc966054..99bdc6c52 100644 --- a/mesonbuild/compilers/c.py +++ b/mesonbuild/compilers/c.py @@ -656,7 +656,7 @@ class CCompiler(Compiler): # glibc defines functions that are not available on Linux as stubs that # fail with ENOSYS (such as e.g. lchmod). In this case we want to fail # instead of detecting the stub as a valid symbol. - # We already included limits.h earlier to ensure that these are defined + # We also include limits.h to ensure that these are defined # for stub functions. stubs_fail = ''' #if defined __stub_{func} || defined __stub___{func} @@ -693,9 +693,10 @@ class CCompiler(Compiler): # can just directly use the __has_builtin() macro. fargs['no_includes'] = '#include' not in prefix t = '''{prefix} + #include <limits.h> int main() {{ #ifdef __has_builtin - #if !__has_builtin(__builtin_{func}) + #if !__has_builtin({func}) #error "__builtin_{func} not found" #endif #elif ! defined({func}) @@ -706,8 +707,11 @@ class CCompiler(Compiler): * give them a workaround. */ #if {no_includes:d} __builtin_{func}; + // See above for why this is needed + #elif defined(__stub_{func}) || defined(_stub__{func}) + #error "unusable function {func}" #else - #error "No definition for __builtin_{func} found in the prefix" + {func}; #endif #endif }}''' |