build: add option to disable -Werror flag

This commit adds possibility to disable treating warnings as errors.
In CrOS EC, define NO_ERRORS=1 as make parameter.
In Zephyr, use --no-errors flag when configuring using zmake.

BRANCH=main
BUG=b:197888003
TEST=Add unused static function.
     Build without flags, compilation should fail.
     Build with no-errors flags, only warning should be visible.

Change-Id: I7f873b7530317b74ff2865f420c4c248b4a95360
Signed-off-by: Michał Barnaś <mb@semihalf.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3264191
Reviewed-by: Keith Short <keithshort@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>

4 files changed, 22 insertions, 2 deletions

diff --git a/Makefile.toolchain b/Makefile.toolchain
index a79f248ea2..a56193201a 100644
--- a/Makefile.toolchain
+++ b/Makefile.toolchain
@@ -59,15 +59,19 @@ GCOV=$(CROSS_COMPILE)gcov
 HOSTGCOV=$(CURDIR)/util/llvm-gcov.sh
 
 C_WARN = -Wstrict-prototypes -Wdeclaration-after-statement -Wno-pointer-sign
-COMMON_WARN = -Wall -Wundef -Werror -Werror-implicit-function-declaration \
+COMMON_WARN = -Wall -Wundef -Werror-implicit-function-declaration \
 	-Wno-trigraphs -Wno-format-security -Wno-address-of-packed-member \
 	-fno-common -fno-strict-aliasing -fno-strict-overflow
+
+ifndef ALLOW_WARNINGS
+COMMON_WARN+=-Werror
 ifeq ($(cc-name),clang)
 COMMON_WARN+=-Werror=uninitialized
 endif
 ifeq ($(cc-name),gcc)
 COMMON_WARN+=-Werror=maybe-uninitialized
 endif
+endif
 
 ifeq ($(cc-name),clang)
 # TODO(b/172020503): Re-enabling this warning requires a large CL.
diff --git a/zephyr/CMakeLists.txt b/zephyr/CMakeLists.txt
index 0ff7f890be..a8b2168c79 100644
--- a/zephyr/CMakeLists.txt
+++ b/zephyr/CMakeLists.txt
@@ -40,7 +40,10 @@ if(DEFINED CONFIG_PLATFORM_EC)
   zephyr_compile_definitions("CONFIG_ZEPHYR")
 
   # Force compiler warnings to generate errors
-  zephyr_compile_options(-Werror)
+  option(ALLOW_WARNINGS "Do not treat warnings as errors")
+  if (NOT ALLOW_WARNINGS)
+    zephyr_compile_options(-Werror)
+  endif()
 
   include(fpu.cmake)
 
diff --git a/zephyr/zmake/zmake/__main__.py b/zephyr/zmake/zmake/__main__.py
index ad4a7d96f0..f776c1dbaa 100644
--- a/zephyr/zmake/zmake/__main__.py
+++ b/zephyr/zmake/zmake/__main__.py
@@ -184,6 +184,12 @@ def main(argv=None):
         help="Enable bringup debugging features",
     )
     configure.add_argument(
+        "--allow-warnings",
+        action="store_true",
+        default=False,
+        help="Do not treat warnings as errors",
+    )
+    configure.add_argument(
         "-B", "--build-dir", type=pathlib.Path, help="Build directory"
     )
     configure.add_argument(
diff --git a/zephyr/zmake/zmake/zmake.py b/zephyr/zmake/zmake/zmake.py
index c924196caa..a5c3cb62a5 100644
--- a/zephyr/zmake/zmake/zmake.py
+++ b/zephyr/zmake/zmake/zmake.py
@@ -214,6 +214,7 @@ class Zmake:
         test_after_configure=False,
         bringup=False,
         coverage=False,
+        allow_warnings=False,
     ):
         """Locate a project by name or directory and then call _configure."""
         root_dir = pathlib.Path(project_name_or_dir)
@@ -238,6 +239,7 @@ class Zmake:
             test_after_configure=test_after_configure,
             bringup=bringup,
             coverage=coverage,
+            allow_warnings=allow_warnings,
         )
 
     def _configure(
@@ -250,6 +252,7 @@ class Zmake:
         test_after_configure=False,
         bringup=False,
         coverage=False,
+        allow_warnings=False,
     ):
         """Set up a build directory to later be built by "zmake build"."""
         supported_version = util.parse_zephyr_version(project.config.zephyr_version)
@@ -319,6 +322,10 @@ class Zmake:
             base_config |= zmake.build_config.BuildConfig(
                 kconfig_defs={"CONFIG_COVERAGE": "y"}
             )
+        if allow_warnings:
+            base_config |= zmake.build_config.BuildConfig(
+                cmake_defs={"ALLOW_WARNINGS": "ON"}
+            )
 
         if not build_dir.exists():
             build_dir = build_dir.mkdir()