compiler_wrapper: add a --version_suffix flag to build.py

This allows us to provide more information about the compiler being
wrapped to the wrapper. The intended use of this is to embed hashes of
the compiler being wrapped into the wrapper itself, so as the compiler
changes, the wrapper's SHA changes with it.

While I'm in the area, fix up a comment, and apply this flag to our
manual wrapper installation script.

BUG=b:222321317
TEST=`emerge llvm`

Change-Id: I20380722e1e539d51fe7ea708c63dad696d84c87
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/3696434
Reviewed-by: Denis Nikitin <denik@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>

3 files changed, 45 insertions, 9 deletions

diff --git a/compiler_wrapper/build.py b/compiler_wrapper/build.py
index 44c398bf..d004b553 100755
--- a/compiler_wrapper/build.py
+++ b/compiler_wrapper/build.py
@@ -23,7 +23,12 @@ def parse_args():
       choices=['cros.hardened', 'cros.nonhardened', 'cros.host', 'android'])
   parser.add_argument('--use_ccache', required=True, choices=['true', 'false'])
   parser.add_argument(
-      '--use_llvm_next', required=True, choices=['true', 'false'])
+      '--version_suffix',
+      help='A string appended to the computed version of the wrapper. This '
+      'is appeneded directly without any delimiter.')
+  parser.add_argument('--use_llvm_next',
+                      required=True,
+                      choices=['true', 'false'])
   parser.add_argument('--output_file', required=True, type=str)
   parser.add_argument(
       '--static',
@@ -41,6 +46,11 @@ def parse_args():
 
 
 def calc_go_args(args, version, build_dir):
+  # These seem unnecessary, and might lead to breakages with Go's ldflag
+  # parsing. Don't allow them.
+  if "'" in version:
+    raise ValueError('`version` should not contain single quotes')
+
   ldFlags = [
       '-X',
       'main.ConfigName=' + args.config,
@@ -49,7 +59,8 @@ def calc_go_args(args, version, build_dir):
       '-X',
       'main.UseLlvmNext=' + args.use_llvm_next,
       '-X',
-      'main.Version=' + version,
+      # Quote this, as `version` may have spaces in it.
+      "'main.Version=" + version + "'",
   ]
 
   # If the wrapper is intended for ChromeOS, we need to use libc's exec.
@@ -60,8 +71,8 @@ def calc_go_args(args, version, build_dir):
   if args.config == 'android':
     # If android_llvm_next_flags.go DNE, we'll get an obscure "no
     # llvmNextFlags" build error; complaining here is clearer.
-    if not os.path.exists(
-        os.path.join(build_dir, 'android_llvm_next_flags.go')):
+    if not os.path.exists(os.path.join(build_dir,
+                                       'android_llvm_next_flags.go')):
       sys.exit('In order to build the Android wrapper, you must have a local '
                'android_llvm_next_flags.go file; please see '
                'cros_llvm_next_flags.go.')
@@ -92,6 +103,8 @@ def main():
   args = parse_args()
   build_dir = os.path.dirname(__file__)
   version = read_version(build_dir)
+  if args.version_suffix:
+    version += args.version_suffix
   # Note: Go does not support using absolute package names.
   # So we run go inside the directory of the the build file.
   sys.exit(
diff --git a/compiler_wrapper/config.go b/compiler_wrapper/config.go
index c275ae9f..25df476f 100644
--- a/compiler_wrapper/config.go
+++ b/compiler_wrapper/config.go
@@ -34,7 +34,7 @@ type config struct {
 	triciumNitsDir string
 	// Directory to store crash artifacts in.
 	crashArtifactsDir string
-	// Version. Only used for printing via -print-cmd.
+	// Version. Only exposed via -print-config.
 	version string
 }
 
diff --git a/compiler_wrapper/install_compiler_wrapper.sh b/compiler_wrapper/install_compiler_wrapper.sh
index f05f2b4c..a503895f 100755
--- a/compiler_wrapper/install_compiler_wrapper.sh
+++ b/compiler_wrapper/install_compiler_wrapper.sh
@@ -11,18 +11,41 @@ if [[ ! -e /etc/cros_chroot_version ]]; then
   exit 1
 fi
 set -e
+
+# Use a unique value here, since folks doing wrapper dev _likely_ want builds
+# to always be redone.
+version_suffix="manually_installed_wrapper_at_unix_$(date +%s.%6N)"
+echo "Using toolchain hash: ${version_suffix}"
 cd "$(dirname "$(readlink -m "$0")")"
+
+build_py() {
+  ./build.py --version_suffix="${version_suffix}" "$@"
+}
+
 echo "Updated files:"
 # Update the host wrapper
-./build.py --config=cros.host --use_ccache=false --use_llvm_next=false --output_file=./clang_host_wrapper
+build_py \
+  --config=cros.host \
+  --use_ccache=false \
+  --use_llvm_next=false \
+  --output_file=./clang_host_wrapper
 sudo mv ./clang_host_wrapper /usr/bin/clang_host_wrapper
 echo "/usr/bin/clang_host_wrapper"
 sudo cp ../binary_search_tool/bisect_driver.py /usr/bin
 echo "/usr/bin/clang_host_wrapper/bisect_driver.py"
 
 # Update the target wrappers
-./build.py --config=cros.hardened --use_ccache=false --use_llvm_next=false --output_file=./sysroot_wrapper.hardened.noccache
-./build.py --config=cros.hardened --use_ccache=true --use_llvm_next=false --output_file=./sysroot_wrapper.hardened.ccache
+build_py \
+  --config=cros.hardened \
+  --use_ccache=false \
+  --use_llvm_next=false \
+  --output_file=./sysroot_wrapper.hardened.noccache
+build_py \
+  --config=cros.hardened \
+  --use_ccache=true \
+  --use_llvm_next=false \
+  --output_file=./sysroot_wrapper.hardened.ccache
+
 # Update clang target wrappers.
 sudo cp ./sysroot_wrapper.hardened.noccache ./sysroot_wrapper.hardened.ccache /usr/bin
 echo "Updated clang wrapper /usr/bin/sysroot_wrapper.hardened.noccache"
@@ -30,7 +53,7 @@ echo "Updated clang wrapper /usr/bin/sysroot_wrapper.hardened.ccache"
 
 # Update GCC target wrappers.
 for GCC in cross-x86_64-cros-linux-gnu/gcc cross-armv7a-cros-linux-gnueabihf/gcc cross-aarch64-cros-linux-gnu/gcc; do
-  if ! FILES="$(equery f ${GCC})"; then
+  if ! FILES="$(equery f "${GCC}")"; then
     if [[ $(equery l "${GCC}" 2>&1 | wc -c) -eq 0 ]]; then
       echo "no ${GCC} package found; skipping" >&2
       continue