Pass the old wrapper path as a linker argument

BUG=chromium:773875
TEST=unit test and comparison to old wrapper

Change-Id: I97cff81f2b42a01f82ba66668693b17a27c14672
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1754130
Tested-by: Tobias Bosch <tbosch@google.com>
Reviewed-by: George Burgess <gbiv@chromium.org>

9 files changed, 53 insertions, 26 deletions

diff --git a/compiler_wrapper/build.py b/compiler_wrapper/build.py
index 33259281..40e8aa64 100755
--- a/compiler_wrapper/build.py
+++ b/compiler_wrapper/build.py
@@ -21,6 +21,7 @@ def parse_args():
       required=True,
       choices=['cros.hardened', 'cros.nonhardened', 'cros.host'])
   parser.add_argument('--use_ccache', required=True, choices=['true', 'false'])
+  parser.add_argument('--old_wrapper_path', required=True)
   parser.add_argument('--output_file', required=True, type=str)
   return parser.parse_args()
 
@@ -30,7 +31,8 @@ def calc_go_args(args):
   # build a fully static binary in go.
   ldFlags = [
       '-X', 'main.ConfigName=' + args.config, '-X',
-      'main.UseCCache=' + args.use_ccache, "-extldflags '-static'"
+      'main.UseCCache=' + args.use_ccache, '-X',
+      'main.OldWrapperPath=' + args.old_wrapper_path, "-extldflags '-static'"
   ]
   return [
       'go', 'build', '-o',
diff --git a/compiler_wrapper/bundle.README b/compiler_wrapper/bundle.README
index a969d934..530d04ea 100644
--- a/compiler_wrapper/bundle.README
+++ b/compiler_wrapper/bundle.README
@@ -5,7 +5,8 @@ found in the LICENSE file.
 Toolchain utils compiler wrapper sources.
 
 Build the wrapper:
-./build --config=<config name> --use_ccache=<bool> --output_file=<file>
+./build --config=<config name> --use_ccache=<bool> \
+  --old_wrapper_path=<path> --output_file=<file>
 
 ATTENTION:
 The files in this folder are generated. Do not modify manually!
diff --git a/compiler_wrapper/config.go b/compiler_wrapper/config.go
index 7567d0e2..70d08c15 100644
--- a/compiler_wrapper/config.go
+++ b/compiler_wrapper/config.go
@@ -29,6 +29,10 @@ type config struct {
 	newWarningsDir string
 }
 
+// OldWrapperPath can be set via a linker flag.
+// Value fills config.oldWrapperPath.
+var OldWrapperPath = ""
+
 // UseCCache can be set via a linker flag.
 // Value will be passed to strconv.ParseBool.
 // E.g. go build -ldflags '-X config.UseCCache=true'.
@@ -46,33 +50,33 @@ func getRealConfig() (*config, error) {
 	if err != nil {
 		return nil, wrapErrorwithSourceLocf(err, "invalid format for UseCCache")
 	}
-	config, err := getConfig(useCCache, ConfigName)
+	config, err := getConfig(useCCache, ConfigName, OldWrapperPath)
 	if err != nil {
 		return nil, err
 	}
 	return config, nil
 }
 
-func getConfig(useCCache bool, configName string) (*config, error) {
+func getConfig(useCCache bool, configName string, oldWrapperPath string) (*config, error) {
 	switch configName {
 	case "cros.hardened":
-		return getCrosHardenedConfig(useCCache), nil
+		return getCrosHardenedConfig(useCCache, oldWrapperPath), nil
 	case "cros.nonhardened":
-		return getCrosNonHardenedConfig(useCCache), nil
+		return getCrosNonHardenedConfig(useCCache, oldWrapperPath), nil
 	case "cros.host":
-		return getCrosHostConfig(), nil
+		return getCrosHostConfig(oldWrapperPath), nil
 	default:
 		return nil, newErrorwithSourceLocf("unknown config name: %s", configName)
 	}
 }
 
 // Full hardening.
-func getCrosHardenedConfig(useCCache bool) *config {
+func getCrosHardenedConfig(useCCache bool, oldWrapperPath string) *config {
 	// Temporarily disable function splitting because of chromium:434751.
 	return &config{
 		useCCache:      useCCache,
 		rootRelPath:    "../../../../..",
-		oldWrapperPath: "./sysroot_wrapper.hardened.old",
+		oldWrapperPath: oldWrapperPath,
 		commonFlags: []string{
 			"-fstack-protector-strong",
 			"-fPIE",
@@ -104,11 +108,11 @@ func getCrosHardenedConfig(useCCache bool) *config {
 }
 
 // Flags to be added to non-hardened toolchain.
-func getCrosNonHardenedConfig(useCCache bool) *config {
+func getCrosNonHardenedConfig(useCCache bool, oldWrapperPath string) *config {
 	return &config{
 		useCCache:      useCCache,
 		rootRelPath:    "../../../../..",
-		oldWrapperPath: "./sysroot_wrapper.old",
+		oldWrapperPath: oldWrapperPath,
 		commonFlags:    []string{},
 		gccFlags: []string{
 			"-Wno-maybe-uninitialized",
@@ -132,12 +136,12 @@ func getCrosNonHardenedConfig(useCCache bool) *config {
 }
 
 // Flags to be added to host toolchain.
-func getCrosHostConfig() *config {
+func getCrosHostConfig(oldWrapperPath string) *config {
 	return &config{
 		isHostWrapper:  true,
 		useCCache:      false,
 		rootRelPath:    "../..",
-		oldWrapperPath: "./host_wrapper.old",
+		oldWrapperPath: oldWrapperPath,
 		commonFlags:    []string{},
 		gccFlags: []string{
 			"-Wno-maybe-uninitialized",
diff --git a/compiler_wrapper/config_test.go b/compiler_wrapper/config_test.go
index 6b2deff7..bdcf5069 100644
--- a/compiler_wrapper/config_test.go
+++ b/compiler_wrapper/config_test.go
@@ -77,6 +77,23 @@ func TestRealConfigWithConfigNameFlag(t *testing.T) {
 	}
 }
 
+func TestRealConfigWithOldWrapperPath(t *testing.T) {
+	resetGlobals()
+	defer resetGlobals()
+	UseCCache = "false"
+	ConfigName = "cros.hardened"
+
+	OldWrapperPath = "somepath"
+
+	cfg, err := getRealConfig()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.oldWrapperPath != "somepath" {
+		t.Fatalf("OldWrapperPath: Expected somepath, got %s", cfg.oldWrapperPath)
+	}
+}
+
 func isSysrootHardened(cfg *config) bool {
 	for _, arg := range cfg.commonFlags {
 		if arg == "-pie" {
@@ -88,6 +105,7 @@ func isSysrootHardened(cfg *config) bool {
 
 func resetGlobals() {
 	// Set all global variables to a defined state.
+	OldWrapperPath = ""
 	ConfigName = "unknown"
 	UseCCache = "unknown"
 }
diff --git a/compiler_wrapper/cros_hardened_config_test.go b/compiler_wrapper/cros_hardened_config_test.go
index 5ae2f7e1..b87320b5 100644
--- a/compiler_wrapper/cros_hardened_config_test.go
+++ b/compiler_wrapper/cros_hardened_config_test.go
@@ -14,14 +14,14 @@ import (
 	"testing"
 )
 
-const oldHardenedWrapperPathForTest = "/usr/x86_64-pc-linux-gnu/x86_64-cros-linux-gnu/gcc-bin/4.9.x/sysroot_wrapper.hardened"
+const oldHardenedWrapperPathForTest = "$CHROOT/usr/x86_64-pc-linux-gnu/x86_64-cros-linux-gnu/gcc-bin/4.9.x/sysroot_wrapper.hardened"
 const crosHardenedGoldenDir = "testdata/cros_hardened_golden"
 const crosHardenedNoCCacheGoldenDir = "testdata/cros_hardened_noccache_golden"
 
 func TestCrosHardenedConfig(t *testing.T) {
 	withTestContext(t, func(ctx *testContext) {
 		useCCache := true
-		ctx.updateConfig(oldHardenedWrapperPathForTest, getCrosHardenedConfig(useCCache))
+		ctx.updateConfig(getCrosHardenedConfig(useCCache, oldHardenedWrapperPathForTest))
 
 		runGoldenRecords(ctx, crosHardenedGoldenDir, createSyswrapperGoldenInputs(ctx))
 	})
@@ -30,7 +30,7 @@ func TestCrosHardenedConfig(t *testing.T) {
 func TestCrosHardenedConfigWithoutCCache(t *testing.T) {
 	withTestContext(t, func(ctx *testContext) {
 		useCCache := false
-		ctx.updateConfig(oldHardenedWrapperPathForTest, getCrosHardenedConfig(useCCache))
+		ctx.updateConfig(getCrosHardenedConfig(useCCache, oldHardenedWrapperPathForTest))
 
 		// Create a copy of the old wrapper where the CCACHE_DEFAULT is false.
 		if ctx.cfg.oldWrapperPath != "" {
diff --git a/compiler_wrapper/cros_host_config_test.go b/compiler_wrapper/cros_host_config_test.go
index a68cedd7..61f1b867 100644
--- a/compiler_wrapper/cros_host_config_test.go
+++ b/compiler_wrapper/cros_host_config_test.go
@@ -9,14 +9,14 @@ import (
 	"testing"
 )
 
-const oldClangHostWrapperPathForTest = "/usr/bin/clang_host_wrapper"
-const oldGccHostWrapperPathForTest = "../src/third_party/chromiumos-overlay/sys-devel/gcc/files/host_wrapper"
+const oldClangHostWrapperPathForTest = "$CHROOT/usr/bin/clang_host_wrapper"
+const oldGccHostWrapperPathForTest = "$CHROOT/../src/third_party/chromiumos-overlay/sys-devel/gcc/files/host_wrapper"
 const crosClangHostGoldenDir = "testdata/cros_clang_host_golden"
 const crosGccHostGoldenDir = "testdata/cros_gcc_host_golden"
 
 func TestCrosClangHostConfig(t *testing.T) {
 	withTestContext(t, func(ctx *testContext) {
-		ctx.updateConfig(oldClangHostWrapperPathForTest, getCrosHostConfig())
+		ctx.updateConfig(getCrosHostConfig(oldClangHostWrapperPathForTest))
 
 		gomaPath := path.Join(ctx.tempDir, "gomacc")
 		ctx.writeFile(gomaPath, "")
@@ -39,7 +39,7 @@ func TestCrosClangHostConfig(t *testing.T) {
 
 func TestCrosGccHostConfig(t *testing.T) {
 	withTestContext(t, func(ctx *testContext) {
-		ctx.updateConfig(oldGccHostWrapperPathForTest, getCrosHostConfig())
+		ctx.updateConfig(getCrosHostConfig(oldGccHostWrapperPathForTest))
 
 		gomaPath := path.Join(ctx.tempDir, "gomacc")
 		ctx.writeFile(gomaPath, "")
diff --git a/compiler_wrapper/cros_nonhardened_config_test.go b/compiler_wrapper/cros_nonhardened_config_test.go
index 41e3d7c9..e876d309 100644
--- a/compiler_wrapper/cros_nonhardened_config_test.go
+++ b/compiler_wrapper/cros_nonhardened_config_test.go
@@ -8,13 +8,13 @@ import (
 	"testing"
 )
 
-const oldNonHardenedWrapperPathForTest = "/usr/x86_64-pc-linux-gnu/arm-none-eabi/gcc-bin/4.9.x/sysroot_wrapper"
+const oldNonHardenedWrapperPathForTest = "$CHROOT/usr/x86_64-pc-linux-gnu/arm-none-eabi/gcc-bin/4.9.x/sysroot_wrapper"
 const crosNonHardenedGoldenDir = "testdata/cros_nonhardened_golden"
 
 func TestCrosNonHardenedConfig(t *testing.T) {
 	withTestContext(t, func(ctx *testContext) {
 		useCCache := true
-		ctx.updateConfig(oldNonHardenedWrapperPathForTest, getCrosNonHardenedConfig(useCCache))
+		ctx.updateConfig(getCrosNonHardenedConfig(useCCache, oldNonHardenedWrapperPathForTest))
 
 		runGoldenRecords(ctx, crosNonHardenedGoldenDir, createSyswrapperGoldenInputs(ctx))
 	})
diff --git a/compiler_wrapper/main.go b/compiler_wrapper/main.go
index 780e9155..3fcf3a66 100644
--- a/compiler_wrapper/main.go
+++ b/compiler_wrapper/main.go
@@ -6,6 +6,8 @@
 // - main.UseCCache: Whether to use ccache.
 // - main.ConfigName: Name of the configuration to use.
 //   See config.go for the supported values.
+// - main.OldWrapperPath: Path to the old wrapper to compare commands
+//   against. Comparison is deactivated if empty.
 //
 // The script ./build simplifies the call to `go build`.
 // E.g. ./build --use_ccache=true --config=cros.hardened will build a
diff --git a/compiler_wrapper/testutil_test.go b/compiler_wrapper/testutil_test.go
index fa321a07..0dbf817e 100644
--- a/compiler_wrapper/testutil_test.go
+++ b/compiler_wrapper/testutil_test.go
@@ -58,7 +58,7 @@ func withTestContext(t *testing.T, work func(ctx *testContext)) {
 		env:     nil,
 		cfg:     &config{},
 	}
-	ctx.updateConfig("", &config{})
+	ctx.updateConfig(&config{})
 
 	work(&ctx)
 }
@@ -140,12 +140,12 @@ func (ctx *testContext) mustFail(exitCode int) string {
 	return ctx.stderrString()
 }
 
-func (ctx *testContext) updateConfig(wrapperChrootPath string, cfg *config) {
+func (ctx *testContext) updateConfig(cfg *config) {
 	*ctx.cfg = *cfg
 	ctx.cfg.mockOldWrapperCmds = true
 	ctx.cfg.newWarningsDir = filepath.Join(ctx.tempDir, "fatal_clang_warnings")
-	if *crosRootDirFlag != "" && wrapperChrootPath != "" {
-		ctx.cfg.oldWrapperPath = filepath.Join(*crosRootDirFlag, wrapperChrootPath)
+	if *crosRootDirFlag != "" && ctx.cfg.oldWrapperPath != "" {
+		ctx.cfg.oldWrapperPath = strings.Replace(ctx.cfg.oldWrapperPath, "$CHROOT", *crosRootDirFlag, -1)
 	} else {
 		ctx.cfg.oldWrapperPath = ""
 	}