Bug 1319222 - Support compiling *.s with yasm; r=chmanchester

The moz.build files that specify USE_YASM = True will get the value of
AS_DASH_C_FLAG and AS overwritten in PassthruVariables. We can save
those in the BackendTupfile and use them in place of the configure or
default settings as appropriate. This enables compilation of those .s
files that are built with yasm.

MozReview-Commit-ID: J66q8nKQ0an

--HG--
extra : rebase_source : 0ee97ef7a2122b42f1d21c473539a2e6352bd9ab

python/mozbuild/mozbuild/backend/tup.py

@@ -35,6 +35,7 @@ from ..frontend.data import (
     ObjdirFiles,
     PerSourceFlag,
     Sources,
+    VariablePassthru,
 )
 from ..util import (
     FileAvoidWrite,
@@ -65,6 +66,7 @@ class BackendTupfile(object):
         self.local_flags = defaultdict(list)
         self.sources = defaultdict(list)
         self.host_sources = defaultdict(list)
+        self.variables = {}
 
         self.fh = FileAvoidWrite(self.name, capture_diff=True)
         self.fh.write('# THIS FILE WAS AUTOMATICALLY GENERATED. DO NOT EDIT.\n')
@@ -121,21 +123,24 @@ class BackendTupfile(object):
     def gen_sources_rules(self, extra_inputs):
         sources = self.sources
         host_sources = self.host_sources
+        as_dash_c = self.variables.get('AS_DASH_C_FLAG', self.environment.substs['AS_DASH_C_FLAG'])
         compilers = [
-            (sources['.S'], 'AS', 'ASFLAGS', ''),
-            (sources['.cpp'], 'CXX', 'CXXFLAGS', ''),
-            (sources['.c'], 'CC', 'CFLAGS', ''),
-            (host_sources['.cpp'], 'HOST_CXX', 'HOST_CXXFLAGS', 'host_'),
-            (host_sources['.c'], 'HOST_CC', 'HOST_CFLAGS', 'host_'),
+            (sources['.S'], 'AS', 'SFLAGS', '-c', ''),
+            (sources['.s'], 'AS', 'ASFLAGS', as_dash_c, ''),
+            (sources['.cpp'], 'CXX', 'CXXFLAGS', '-c', ''),
+            (sources['.c'], 'CC', 'CFLAGS', '-c', ''),
+            (host_sources['.cpp'], 'HOST_CXX', 'HOST_CXXFLAGS', '-c', 'host_'),
+            (host_sources['.c'], 'HOST_CC', 'HOST_CFLAGS', '-c', 'host_'),
         ]
-        for srcs, compiler, flags, prefix in compilers:
+        for srcs, compiler, flags, dash_c, prefix in compilers:
             for src in sorted(srcs):
                 # AS can be set to $(CC), so we need to call expand_variables on
                 # the compiler to get the real value.
-                cmd = [expand_variables(self.environment.substs[compiler], self.environment.substs)]
+                compiler_value = self.variables.get(compiler, self.environment.substs[compiler])
+                cmd = [expand_variables(compiler_value, self.environment.substs)]
                 cmd.extend(shell_quote(f) for f in self.local_flags[flags])
                 cmd.extend(shell_quote(f) for f in self.per_source_flags[src])
-                cmd.extend(['-c', '%f', '-o', '%o'])
+                cmd.extend([dash_c, '%f', '-o', '%o'])
                 self.rule(
                     cmd=cmd,
                     inputs=[src],
@@ -280,6 +285,8 @@ class TupOnly(CommonBackend, PartialBackend):
                 backend_file.sources[obj.canonical_suffix].extend(obj.files)
         elif isinstance(obj, HostSources):
             backend_file.host_sources[obj.canonical_suffix].extend(obj.files)
+        elif isinstance(obj, VariablePassthru):
+            backend_file.variables = obj.variables
 
         return True