compiler_wrapper: disable -Wno-error on conftest-y files

There are some ebuilds that (unfortunately) run configure steps inside
of their regular `make` invocations. Rather than trying to fix those as
they pop up, add a heuristic to our -Wno-error bits. This is similar to
a heuristic goma added a while back when experimenting with full builds
of CrOS using goma.

BUG=None
TEST=unittests

Change-Id: I23efdc8ad5ea29621b105040bc33786896f6e486
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2132722
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>

2 files changed, 48 insertions, 1 deletions

diff --git a/compiler_wrapper/disable_werror_flag.go b/compiler_wrapper/disable_werror_flag.go
index 3decbf29..2800c5fa 100644
--- a/compiler_wrapper/disable_werror_flag.go
+++ b/compiler_wrapper/disable_werror_flag.go
@@ -41,6 +41,20 @@ func disableWerrorFlags(originalArgs []string) []string {
 	return noErrors
 }
 
+func isLikelyAConfTest(cfg *config, cmd *command) bool {
+	// Android doesn't do mid-build `configure`s, so we don't need to worry about this there.
+	if cfg.isAndroidWrapper {
+		return false
+	}
+
+	for _, a := range cmd.Args {
+		if strings.HasPrefix(a, "conftest.c") {
+			return true
+		}
+	}
+	return false
+}
+
 func doubleBuildWithWNoError(env env, cfg *config, newWarningsDir string, originalCmd *command) (exitCode int, err error) {
 	originalStdoutBuffer := &bytes.Buffer{}
 	originalStderrBuffer := &bytes.Buffer{}
@@ -62,7 +76,7 @@ func doubleBuildWithWNoError(env env, cfg *config, newWarningsDir string, origin
 	}
 	// The only way we can do anything useful is if it looks like the failure
 	// was -Werror-related.
-	if originalExitCode == 0 || !bytes.Contains(originalStderrBuffer.Bytes(), []byte("-Werror")) {
+	if originalExitCode == 0 || !bytes.Contains(originalStderrBuffer.Bytes(), []byte("-Werror")) || isLikelyAConfTest(cfg, originalCmd) {
 		originalStdoutBuffer.WriteTo(env.stdout())
 		originalStderrBuffer.WriteTo(env.stderr())
 		return originalExitCode, nil
diff --git a/compiler_wrapper/disable_werror_flag_test.go b/compiler_wrapper/disable_werror_flag_test.go
index bd4d376e..9d762599 100644
--- a/compiler_wrapper/disable_werror_flag_test.go
+++ b/compiler_wrapper/disable_werror_flag_test.go
@@ -71,6 +71,39 @@ func TestDoubleBuildWithWNoErrorFlag(t *testing.T) {
 	})
 }
 
+func TestKnownConfigureFileParsing(t *testing.T) {
+	withTestContext(t, func(ctx *testContext) {
+		for _, f := range []string{"conftest.c", "conftest.cpp"} {
+			if !isLikelyAConfTest(ctx.cfg, ctx.newCommand(clangX86_64, f)) {
+				t.Errorf("%q isn't considered a conf test file", f)
+			}
+		}
+	})
+}
+
+func TestDoubleBuildWithKnownConfigureFile(t *testing.T) {
+	withForceDisableWErrorTestContext(t, func(ctx *testContext) {
+		ctx.cmdMock = func(cmd *command, stdin io.Reader, stdout io.Writer, stderr io.Writer) error {
+			switch ctx.cmdCount {
+			case 1:
+				if err := verifyArgCount(cmd, 0, "-Wno-error"); err != nil {
+					return err
+				}
+				fmt.Fprint(stderr, "-Werror originalerror")
+				return newExitCodeError(1)
+			default:
+				t.Fatalf("unexpected command: %#v", cmd)
+				return nil
+			}
+		}
+
+		ctx.mustFail(callCompiler(ctx, ctx.cfg, ctx.newCommand(clangX86_64, "conftest.c")))
+		if ctx.cmdCount != 1 {
+			t.Errorf("expected 1 call. Got: %d", ctx.cmdCount)
+		}
+	})
+}
+
 func TestDoubleBuildWithWNoErrorAndCCache(t *testing.T) {
 	withForceDisableWErrorTestContext(t, func(ctx *testContext) {
 		ctx.cfg.useCCache = true