Save deps when asflags contains -xassembler-with-cpp

Usually, ".S" files are processes with the c preprocessor, and ".s"
files are not, so they don't have any dependency information, since it
is generated by the preprocessor.

But with the -xassembler-with-cpp flag, ".s" files are processed with
the preprocessor, so we should ask for dependency information from them.

Test: NINJA_ARGS="-t deps out/soong/.intermediates/external/sonivox/arm-wt-22k/libsonivox/android_arm_armv7-a-neon_core_static/obj/external/sonivox/arm-wt-22k/lib_src/ARM-E_filter_gnu.o" m
Test: treehugger
Change-Id: Iee7baeebc2b205b5a2f33e7c1705ea4a5b4fc95a

cc/builder.go

@@ -271,6 +271,8 @@ type builderFlags struct {
 	sAbiDump        bool
 	emitXrefs       bool
 
+	assemblerWithCpp bool
+
 	systemIncludeFlags string
 
 	groupStaticLibs bool
@@ -428,7 +430,9 @@ func TransformSourceToObj(ctx android.ModuleContext, subdir string, srcFiles and
 
 		switch srcFile.Ext() {
 		case ".s":
+			if !flags.assemblerWithCpp {
 				rule = ccNoDeps
+			}
 			fallthrough
 		case ".S":
 			ccCmd = "clang"

cc/cc.go

@@ -174,6 +174,7 @@ type Flags struct {
 	CFlagsDeps  android.Paths // Files depended on by compiler flags
 	LdFlagsDeps android.Paths // Files depended on by linker flags
 
+	AssemblerWithCpp bool
 	GroupStaticLibs  bool
 
 	proto            android.ProtoFlags
@@ -1053,6 +1054,9 @@ func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 	if c.sabi != nil {
 		flags = c.sabi.flags(ctx, flags)
 	}
+
+	flags.AssemblerWithCpp = inList("-xassembler-with-cpp", flags.AsFlags)
+
 	// Optimization to reduce size of build.ninja
 	// Replace the long list of flags for each file with a module-local variable
 	ctx.Variable(pctx, "cflags", strings.Join(flags.CFlags, " "))

cc/util.go

@@ -79,6 +79,7 @@ func flagsToBuilderFlags(in Flags) builderFlags {
 
 		systemIncludeFlags: strings.Join(in.SystemIncludeFlags, " "),
 
+		assemblerWithCpp: in.AssemblerWithCpp,
 		groupStaticLibs:  in.GroupStaticLibs,
 
 		proto:            in.proto,