Allow to pass in the use_ccache via go build.

Removes usage of go build tags in favor of passing in
configuration via -ldflags -X ...

BUG=chromium:773875
TEST=unit test

Change-Id: I4e8a58e1679b2858e9d4620d6b9c7a35ad08a6ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1670987
Reviewed-by: George Burgess <gbiv@chromium.org>
Tested-by: Tobias Bosch <tbosch@google.com>

1 files changed, 97 insertions, 49 deletions

diff --git a/compiler_wrapper/config.go b/compiler_wrapper/config.go
index 909edf0a..1e78fbef 100644
--- a/compiler_wrapper/config.go
+++ b/compiler_wrapper/config.go
@@ -1,6 +1,13 @@
 package main
 
+import (
+	"fmt"
+	"strconv"
+)
+
 type config struct {
+	// Whether to use ccache.
+	useCCache bool
 	// Flags to add to gcc and clang.
 	commonFlags []string
 	// Flags to add to gcc only.
@@ -14,57 +21,98 @@ type config struct {
 	overrideOldWrapperConfig bool
 }
 
+// UseCCache can be set via a linker flag.
+// Value will be passed to strconv.ParseBool.
+// E.g. go build -ldflags '-X config.UseCCache=true'.
+var UseCCache = "unknown"
+
+// ConfigName can be set via a linker flag.
+// Value has to be one of:
+// - "cros.hardened"
+// - "cros.nonhardened"
+var ConfigName = "unknown"
+
+// Returns the configuration matching the UseCCache and ConfigName.
+func getRealConfig() (*config, error) {
+	useCCache, err := strconv.ParseBool(UseCCache)
+	if err != nil {
+		return nil, fmt.Errorf("Parse error for UseCCache: %s", err)
+	}
+	config, err := getConfig(useCCache, ConfigName)
+	if err != nil {
+		return nil, err
+	}
+	return config, nil
+}
+
+func getConfig(useCCache bool, configName string) (*config, error) {
+	switch configName {
+	case "cros.hardened":
+		return getCrosHardenedConfig(useCCache), nil
+	case "cros.nonhardened":
+		return getCrosNonHardenedConfig(useCCache), nil
+	default:
+		return nil, fmt.Errorf("Unknown config name: %s", configName)
+	}
+}
+
 // Full hardening.
-// Temporarily disable function splitting because of chromium:434751.
-var crosHardenedConfig = config{
-	rootRelPath:    "../../../../..",
-	oldWrapperPath: "./sysroot_wrapper.hardened.old",
-	commonFlags: []string{
-		"-fPIE",
-		"-D_FORTIFY_SOURCE=2",
-		"-fstack-protector-strong",
-		"-pie",
-		"-fno-omit-frame-pointer",
-	},
-	gccFlags: []string{
-		"-Wno-unused-local-typedefs",
-		"-Wno-maybe-uninitialized",
-		"-fno-reorder-blocks-and-partition",
-	},
-	// Temporarily disable tautological-*-compare chromium:778316.
-	// Temporarily add no-unknown-warning-option to deal with old clang versions.
-	// Temporarily disable Wsection since kernel gets a bunch of these. chromium:778867
-	// Disable "-faddrsig" since it produces object files that strip doesn't understand, chromium:915742.
-	clangFlags: []string{
-		"-Wno-tautological-unsigned-enum-zero-compare",
-		"-Qunused-arguments",
-		"-grecord-gcc-switches",
-		"-Wno-section",
-		"-Wno-unknown-warning-option",
-		"-fno-addrsig",
-		"-Wno-tautological-constant-compare",
-	},
+func getCrosHardenedConfig(useCCache bool) *config {
+	// Temporarily disable function splitting because of chromium:434751.
+	return &config{
+		useCCache:      useCCache,
+		rootRelPath:    "../../../../..",
+		oldWrapperPath: "./sysroot_wrapper.hardened.old",
+		commonFlags: []string{
+			"-fPIE",
+			"-D_FORTIFY_SOURCE=2",
+			"-fstack-protector-strong",
+			"-pie",
+			"-fno-omit-frame-pointer",
+		},
+		gccFlags: []string{
+			"-Wno-unused-local-typedefs",
+			"-Wno-maybe-uninitialized",
+			"-fno-reorder-blocks-and-partition",
+		},
+		// Temporarily disable tautological-*-compare chromium:778316.
+		// Temporarily add no-unknown-warning-option to deal with old clang versions.
+		// Temporarily disable Wsection since kernel gets a bunch of these. chromium:778867
+		// Disable "-faddrsig" since it produces object files that strip doesn't understand, chromium:915742.
+		clangFlags: []string{
+			"-Wno-tautological-unsigned-enum-zero-compare",
+			"-Qunused-arguments",
+			"-grecord-gcc-switches",
+			"-Wno-section",
+			"-Wno-unknown-warning-option",
+			"-fno-addrsig",
+			"-Wno-tautological-constant-compare",
+		},
+	}
 }
 
 // Flags to be added to non-hardened toolchain.
-var crosNonHardenedConfig = config{
-	rootRelPath:    "../../../../..",
-	oldWrapperPath: "./sysroot_wrapper.old",
-	commonFlags:    []string{},
-	gccFlags: []string{
-		"-Wno-unused-local-typedefs",
-		"-Wno-maybe-uninitialized",
-		"-Wtrampolines",
-		"-Wno-deprecated-declarations",
-	},
-	// Temporarily disable tautological-*-compare chromium:778316.
-	// Temporarily add no-unknown-warning-option to deal with old clang versions.
-	// Temporarily disable Wsection since kernel gets a bunch of these. chromium:778867
-	clangFlags: []string{
-		"-Wno-unknown-warning-option",
-		"-Qunused-arguments",
-		"-Wno-section",
-		"-Wno-tautological-unsigned-enum-zero-compare",
-		"-Wno-tautological-constant-compare",
-	},
+func getCrosNonHardenedConfig(useCCache bool) *config {
+	return &config{
+		useCCache:      useCCache,
+		rootRelPath:    "../../../../..",
+		oldWrapperPath: "./sysroot_wrapper.old",
+		commonFlags:    []string{},
+		gccFlags: []string{
+			"-Wno-unused-local-typedefs",
+			"-Wno-maybe-uninitialized",
+			"-Wtrampolines",
+			"-Wno-deprecated-declarations",
+		},
+		// Temporarily disable tautological-*-compare chromium:778316.
+		// Temporarily add no-unknown-warning-option to deal with old clang versions.
+		// Temporarily disable Wsection since kernel gets a bunch of these. chromium:778867
+		clangFlags: []string{
+			"-Wno-unknown-warning-option",
+			"-Qunused-arguments",
+			"-Wno-section",
+			"-Wno-tautological-unsigned-enum-zero-compare",
+			"-Wno-tautological-constant-compare",
+		},
+	}
 }