compilers: avoid one or more version_compare per target

version_compare can take a few milliseconds.  If you have a thousand object files
or a multiple thereof, it adds up.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>

mesonbuild/backend/ninjabackend.py

@@ -623,6 +623,7 @@ class NinjaBackend(backends.Backend):
         if ninja is None:
             raise MesonException('Could not detect Ninja v1.8.2 or newer')
         (self.ninja_command, self.ninja_version) = ninja
+        self.ninja_has_dyndeps = mesonlib.version_compare(self.ninja_version, '>=1.10.0')
         outfilename = os.path.join(self.environment.get_build_dir(), self.ninja_filename)
         tempfilename = outfilename + '~'
         with open(tempfilename, 'w', encoding='utf-8') as outfile:
@@ -1089,7 +1090,7 @@ class NinjaBackend(backends.Backend):
                 self.add_build(elem)
 
     def should_use_dyndeps_for_target(self, target: 'build.BuildTarget') -> bool:
-        if mesonlib.version_compare(self.ninja_version, '<1.10.0'):
+        if not self.ninja_has_dyndeps:
             return False
         if 'fortran' in target.compilers:
             return True
@@ -2451,7 +2452,7 @@ class NinjaBackend(backends.Backend):
         '''Use the new Ninja feature for scanning dependencies during build,
         rather than up front. Remove this and all old scanning code once Ninja
         minimum version is bumped to 1.10.'''
-        return mesonlib.version_compare(self.ninja_version, '>=1.10.0')
+        return self.ninja_has_dyndeps
 
     def generate_fortran_dep_hack(self, crstr: str) -> None:
         if self.use_dyndeps_for_fortran():

mesonbuild/compilers/mixins/gnu.py

@@ -550,16 +550,19 @@ class GnuCompiler(GnuLikeCompiler):
         super().__init__()
         self.defines = defines or {}
         self.base_options.update({OptionKey('b_colorout'), OptionKey('b_lto_threads')})
+        self._has_color_support = mesonlib.version_compare(self.version, '>=4.9.0')
+        self._has_wpedantic_support = mesonlib.version_compare(self.version, '>=4.8.0')
+        self._has_lto_auto_support = mesonlib.version_compare(self.version, '>=10.0')
 
     def get_colorout_args(self, colortype: str) -> T.List[str]:
-        if mesonlib.version_compare(self.version, '>=4.9.0'):
+        if self._has_color_support:
             return gnu_color_args[colortype][:]
         return []
 
     def get_warn_args(self, level: str) -> T.List[str]:
         # Mypy doesn't understand cooperative inheritance
         args = super().get_warn_args(level)
-        if mesonlib.version_compare(self.version, '<4.8.0') and '-Wpedantic' in args:
+        if not self._has_wpedantic_support and '-Wpedantic' in args:
             # -Wpedantic was added in 4.8.0
             # https://gcc.gnu.org/gcc-4.8/changes.html
             args[args.index('-Wpedantic')] = '-pedantic'
@@ -612,7 +615,7 @@ class GnuCompiler(GnuLikeCompiler):
 
     def get_lto_compile_args(self, *, threads: int = 0, mode: str = 'default') -> T.List[str]:
         if threads == 0:
-            if mesonlib.version_compare(self.version, '>= 10.0'):
+            if self._has_lto_auto_support:
                 return ['-flto=auto']
             # This matches clang's behavior of using the number of cpus
             return [f'-flto={multiprocessing.cpu_count()}']

mesonbuild/compilers/vala.py

@@ -31,6 +31,7 @@ class ValaCompiler(Compiler):
         self.version = version
         self.base_options = {OptionKey('b_colorout')}
         self.force_link = False
+        self._has_color_support = version_compare(self.version, '>=0.37.1')
 
     def needs_static_linker(self) -> bool:
         return False # Because compiles into C.
@@ -80,7 +81,7 @@ class ValaCompiler(Compiler):
         return ['--fatal-warnings']
 
     def get_colorout_args(self, colortype: str) -> T.List[str]:
-        if version_compare(self.version, '>=0.37.1'):
+        if self._has_color_support:
             return ['--color=' + colortype]
         return []