Initial version of a go version of the compiler wrapper.

Still calls the old wrapper if one of the following flags is given:
- Xclang-path
- clang-syntax
- env WITH_TIDY
- env FORCE_DISABLE_WERROR
- env GETRUSAGE
- env BISECT_STAGE

BUG=chromium:773875
TEST=Unit tests that also verify the produced command against the
TEST=existing compiler wrapper.

Change-Id: I1e0a720ce9f485d8015deefb2682f2cb760d82e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1652057
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Tobias Bosch <tbosch@google.com>
Reviewed-by: George Burgess <gbiv@chromium.org>
Tested-by: Tobias Bosch <tbosch@google.com>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>

1 files changed, 56 insertions, 0 deletions

diff --git a/compiler_wrapper/main.go b/compiler_wrapper/main.go
new file mode 100644
index 00000000..5323a301
--- /dev/null
+++ b/compiler_wrapper/main.go
@@ -0,0 +1,56 @@
+// +build cros
+
+// This binary uses the following build tags:
+// - cros: Whether the wrapper should be built for ChromeOS
+// - nonhardened: For a non-hardened set of compiler flags
+// - hardened: For a hardened set of compiler flags
+//
+// There is a bash script for every meaningful combination.
+// E.g. ./build_cros_hardened_wrapper.sh will build the ChromeOS
+// hardened compiler wrapper.
+//
+// Test arguments:
+// - crosroot: Specifies the ChromeOS toolchain root directory (aka chroot).
+//   If this is given, tests will compare the produced commands against the
+//   old compiler wrapper.
+//
+// Examples:
+// - run all tests and compare output against old compiler wrapper:
+// 		go test third_party/toolchain-utils/compiler_wrapper/ -v --crosroot=$HOME/chromiumos/chroot/
+// - run all tests in isolation:
+// 		go test third_party/toolchain-utils/compiler_wrapper/ -v
+package main
+
+import (
+	"log"
+	"os/exec"
+	"syscall"
+)
+
+func main() {
+	wrapperCmd := newProcessCommand()
+	env, err := newProcessEnv()
+	if err != nil {
+		log.Fatal(err)
+	}
+	cfg := getRealConfig()
+	if shouldForwardToOldWrapper(env, wrapperCmd) {
+		err := forwardToOldWrapper(env, cfg, wrapperCmd)
+		if err != nil {
+			log.Fatal(err)
+		}
+		return
+	}
+
+	cmd, err := calcCompilerCommandAndCompareToOld(env, cfg, wrapperCmd)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := execCmd(newExecCmd(env, cmd)); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func execCmd(cmd *exec.Cmd) error {
+	return syscall.Exec(cmd.Path, cmd.Args, cmd.Env)
+}