Introduce infrastructure for calling and testing nested

commands, error messages and exit codes.

Also:
- implements the -Xclang-path= flag as use case of calling
  a nested command.
- adds tests for forwarding errors, comparing against the
  old wrapper, and exit codes.
- captures the source locations of errors in error messages.
- compares exit codes of new wrapper and old wrapper.

BUG=chromium:773875
TEST=unit test

Change-Id: I919e58091d093d68939809f676f799a68ec7a34e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1676833
Reviewed-by: George Burgess <gbiv@chromium.org>
Tested-by: Tobias Bosch <tbosch@google.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler_wrapper/gcc_flags.go b/compiler_wrapper/gcc_flags.go
index 352b38e4..ffbde316 100644
--- a/compiler_wrapper/gcc_flags.go
+++ b/compiler_wrapper/gcc_flags.go
@@ -12,13 +12,13 @@ func processGccFlags(builder *commandBuilder) {
 	}
 
 	builder.transformArgs(func(arg builderArg) string {
-		if unsupported[arg.Value] {
+		if unsupported[arg.value] {
 			return ""
 		}
-		if mapped, ok := clangToGcc[arg.Value]; ok {
+		if mapped, ok := clangToGcc[arg.value]; ok {
 			return mapped
 		}
-		return arg.Value
+		return arg.value
 	})
 
 	builder.path += ".real"