Merge "Define CLANG_TIDY_UNKNOWN_CFLAGS for build/make."

cc/config/tidy.go

@@ -19,6 +19,13 @@ import (
 	"strings"
 )
 
+// clang-tidy doesn't recognize every flag that clang does. This is unlikely to
+// be a complete list, but we can populate this with the ones we know to avoid
+// issues with clang-diagnostic-unused-command-line-argument.
+var ClangTidyUnknownCflags = sorted([]string{
+	"-Wa,%",
+})
+
 func init() {
 	// Most Android source files are not clang-tidy clean yet.
 	// Global tidy checks include only google*, performance*,

cc/makevars.go

@@ -75,6 +75,7 @@ func makeVarsProvider(ctx android.MakeVarsContext) {
 	ctx.Strict("LLVM_OBJCOPY", "${config.ClangBin}/llvm-objcopy")
 	ctx.Strict("LLVM_STRIP", "${config.ClangBin}/llvm-strip")
 	ctx.Strict("PATH_TO_CLANG_TIDY", "${config.ClangBin}/clang-tidy")
+	ctx.Strict("CLANG_TIDY_UNKNOWN_CFLAGS", strings.Join(config.ClangTidyUnknownCflags, " "))
 	ctx.StrictSorted("CLANG_CONFIG_UNKNOWN_CFLAGS", strings.Join(config.ClangUnknownCflags, " "))
 
 	ctx.Strict("RS_LLVM_PREBUILTS_VERSION", "${config.RSClangVersion}")