Added functionality to pick the first supported argument from a list. Closes #583.

mesonbuild/compilers.py

@@ -293,7 +293,7 @@ class Compiler():
     def get_library_dirs(self):
         return []
 
-    def has_arg(self, arg):
+    def has_argument(self, arg):
         raise EnvironmentException('Language {} does not support has_arg.'.format(self.language))
 
 class CCompiler(Compiler):
@@ -824,7 +824,7 @@ void bar() {
     def thread_link_flags(self):
         return ['-pthread']
 
-    def has_arg(self, arg):
+    def has_argument(self, arg):
         return self.compiles('int i;\n', extra_args=arg)
 
 class CPPCompiler(CCompiler):

mesonbuild/interpreter.py

@@ -583,7 +583,8 @@ class CompilerHolder(InterpreterObject):
                              'version' : self.version_method,
                              'cmd_array' : self.cmd_array_method,
                              'find_library': self.find_library_method,
-                             'has_arg' : self.has_arg_method,
+                             'has_argument' : self.has_argument_method,
+                             'first_supported_argument' : self.first_supported_argument_method,
                             })
 
     def version_method(self, args, kwargs):
@@ -790,11 +791,25 @@ class CompilerHolder(InterpreterObject):
         lib = dependencies.ExternalLibrary(libname, linkargs)
         return ExternalLibraryHolder(lib)
 
-    def has_arg_method(self, args, kwargs):
+    def has_argument_method(self, args, kwargs):
         args = mesonlib.stringlistify(args)
         if len(args) != 1:
             raise InterpreterException('Has_arg takes exactly one argument.')
-        return self.compiler.has_arg(args[0])
+        result = self.compiler.has_argument(args[0])
+        if result:
+            h = mlog.green('YES')
+        else:
+            h = mlog.red('NO')
+        mlog.log('Compiler for {} supports argument {}:'.format(self.compiler.language, args[0]), h)
+        return result
+
+    def first_supported_argument_method(self, args, kwargs):
+        for i in mesonlib.stringlistify(args):
+            if self.compiler.has_argument(i):
+                mlog.log('First supported argument:', mlog.bold(i))
+                return [i]
+        mlog.log('First supported argument:', mlog.red('None'))
+        return []
 
 class ModuleState:
     pass

test cases/common/112 has arg/meson.build

@@ -4,11 +4,21 @@ cc = meson.get_compiler('c')
 
 if cc.get_id() == 'msvc'
   is_arg = '/O2'
+  useless = '/DFOO'
 else
   is_arg = '-O2'
+  useless = '-DFOO'
 endif
 
 isnt_arg = '-fiambroken'
 
-assert(cc.has_arg(is_arg), 'Arg that should have worked does not work.')
-assert(not cc.has_arg(isnt_arg), 'Arg that should be broken is not.')
+assert(cc.has_argument(is_arg), 'Arg that should have worked does not work.')
+assert(not cc.has_argument(isnt_arg), 'Arg that should be broken is not.')
+
+# Have useless at the end to ensure that the search goes from front to back.
+l1 = cc.first_supported_argument([isnt_arg, is_arg, isnt_arg, useless])
+l2 = cc.first_supported_argument(isnt_arg, isnt_arg, isnt_arg)
+
+assert(l1.length() == 1, 'First supported returned wrong result.')
+assert(l1.get(0) == is_arg, 'First supported returned wrong argument.')
+assert(l2.length() == 0, 'First supported did not return empty array.')