compilers: Cache compiler checks where we don't want the output

This caching is only for a single run, so it doesn't help reconfigure.
However, it is useful for subproject setups where different subprojects
will run the same compiler checks.

The cache is also per compiler instance and is not used for functions
that want to read or run the outputted object file or binary.

For gst-build, this halves the number of compiler checks that are run
and reduces configuration time by 20%.

1 files changed, 5 insertions, 5 deletions

diff --git a/mesonbuild/compilers/c.py b/mesonbuild/compilers/c.py
index 27cf43a..dee5125 100644
--- a/mesonbuild/compilers/c.py
+++ b/mesonbuild/compilers/c.py
@@ -319,16 +319,16 @@ class CCompiler(Compiler):
         args += extra_args
         return args
 
-    def compiles(self, code, env, extra_args=None, dependencies=None, mode='compile'):
+    def compiles(self, code, env, extra_args=None, dependencies=None, mode='compile', want_output=False):
         args = self._get_compiler_check_args(env, extra_args, dependencies, mode)
         # We only want to compile; not link
         with self.compile(code, args.to_native(), mode) as p:
             return p.returncode == 0
 
-    def _links_wrapper(self, code, env, extra_args, dependencies):
+    def _links_wrapper(self, code, env, extra_args, dependencies, want_output=False):
         "Shares common code between self.links and self.run"
         args = self._get_compiler_check_args(env, extra_args, dependencies, mode='link')
-        return self.compile(code, args)
+        return self.compile(code, args, want_output=want_output)
 
     def links(self, code, env, extra_args=None, dependencies=None):
         with self._links_wrapper(code, env, extra_args, dependencies) as p:
@@ -337,7 +337,7 @@ class CCompiler(Compiler):
     def run(self, code, env, extra_args=None, dependencies=None):
         if self.is_cross and self.exe_wrapper is None:
             raise CrossNoRunException('Can not run test applications in this cross environment.')
-        with self._links_wrapper(code, env, extra_args, dependencies) as p:
+        with self._links_wrapper(code, env, extra_args, dependencies, True) as p:
             if p.returncode != 0:
                 mlog.debug('Could not compile test file %s: %d\n' % (
                     p.input_name,
@@ -736,7 +736,7 @@ class CCompiler(Compiler):
         args = self.get_cross_extra_flags(env, link=False)
         args += self.get_compiler_check_args()
         n = 'symbols_have_underscore_prefix'
-        with self.compile(code, args, 'compile') as p:
+        with self.compile(code, args, 'compile', want_output=True) as p:
             if p.returncode != 0:
                 m = 'BUG: Unable to compile {!r} check: {}'
                 raise RuntimeError(m.format(n, p.stdo))