bazel/buildrc - skia - Git at Google

 # This file contains the build configurations of Skia that we use for testing on the CI.
 # These allow a short-form reference for our supported combinations of build features.
 # https://bazel.build/docs/bazelrc#config
 #
 # For most build configurations, we will want to set the --cc_output_directory_tag [1]
 # with a unique identifier per configuration name.
 #
 # By default, Bazel's "unique target BuildConfiguration" [2] incorporates the compilation_mode,
 # the target platform, and some suffixes to avoid Bazel-caused and user-caused conflicts. [3] [4]
 # For example, a default output directory might look like "k8-fastbuild-ST-6a54c1377847".
 # Inside this output directory is a subfolder for the target (e.g. executable) name.
 #
 # Notably, the flags that we turn on and off via //bazel/common_config_settings do not affect
 # the output directory. The output directory is used to store compiled object files (.o files)
 # and generated dependency files (e.g. the output of clang --write-dependencies [5]), so having
 # these be overwritten unnecessarily will slow down incremental rebuilds when switching between
 # building different configurations of the same targets.
 #
 # [1] https://bazel.build/reference/command-line-reference#flag--cc_output_directory_tag
 # [2] https://bazel.build/docs/output_directories#layout-diagram
 # [3] https://github.com/bazelbuild/bazel/blob/ad37a3748c78e0ee903b56366322c70ab8b22187/CODEBASE.md#the-structure-of-the-output-directory
 # [4] https://github.com/bazelbuild/bazel/blob/e0e589658463beb9605030b4820dcc97e6a36f48/src/main/java/com/google/devtools/build/lib/analysis/config/OutputDirectories.java#L198-L236
 # [5] https://clang.llvm.org/docs/ClangCommandLineReference.html#dependency-file-generation

 # These are examples of the syntax to create build configurations. As of May 2022, our
 # Bazel configurations are still being made.
 build:release --compilation_mode=opt
 build:debug --compilation_mode=dbg

 # We use spawn_strategy=local for CanvasKit builds because emscripten assumes there
 # is a cache in the home directory that it needs to fill with compiled versions of libc etc.
 # https://emscripten.org/docs/tools_reference/emcc.html
 # By setting spawn_strategy=local, we can avoid recompiling all of this for every compilation
 # unit, by letting the cache be used (and not dropped from the sandbox), which gets expensive.
 # Local testing showed using the local strategy sped up a clean build from 9.5 minutes
 # to 1 minute. https://bazel.build/docs/user-manual#execution-strategy
 build:ck_release --config=release --spawn_strategy=local
 build:ck_debug --config=debug --spawn_strategy=local

 # We only want to enforce IWYU on debug builds because we have some things that are only
 # necessary to include in debug mode (e.g. SkDEBUGCODE), but very rarely something that is
 # only needed in release mode. Thus our C++ debug includes should be a superset of the
 # release includes.
 build:enforce_iwyu --features=skia_enforce_iwyu --cc_output_directory_tag=iwyu --compilation_mode=dbg
	# This file contains the build configurations of Skia that we use for testing on the CI.
	# These allow a short-form reference for our supported combinations of build features.
	# https://bazel.build/docs/bazelrc#config
	#
	# For most build configurations, we will want to set the --cc_output_directory_tag [1]
	# with a unique identifier per configuration name.
	#
	# By default, Bazel's "unique target BuildConfiguration" [2] incorporates the compilation_mode,
	# the target platform, and some suffixes to avoid Bazel-caused and user-caused conflicts. [3] [4]
	# For example, a default output directory might look like "k8-fastbuild-ST-6a54c1377847".
	# Inside this output directory is a subfolder for the target (e.g. executable) name.
	#
	# Notably, the flags that we turn on and off via //bazel/common_config_settings do not affect
	# the output directory. The output directory is used to store compiled object files (.o files)
	# and generated dependency files (e.g. the output of clang --write-dependencies [5]), so having
	# these be overwritten unnecessarily will slow down incremental rebuilds when switching between
	# building different configurations of the same targets.
	#
	# [1] https://bazel.build/reference/command-line-reference#flag--cc_output_directory_tag
	# [2] https://bazel.build/docs/output_directories#layout-diagram
	# [3] https://github.com/bazelbuild/bazel/blob/ad37a3748c78e0ee903b56366322c70ab8b22187/CODEBASE.md#the-structure-of-the-output-directory
	# [4] https://github.com/bazelbuild/bazel/blob/e0e589658463beb9605030b4820dcc97e6a36f48/src/main/java/com/google/devtools/build/lib/analysis/config/OutputDirectories.java#L198-L236
	# [5] https://clang.llvm.org/docs/ClangCommandLineReference.html#dependency-file-generation

	# These are examples of the syntax to create build configurations. As of May 2022, our
	# Bazel configurations are still being made.
	build:release --compilation_mode=opt
	build:debug --compilation_mode=dbg

	# We use spawn_strategy=local for CanvasKit builds because emscripten assumes there
	# is a cache in the home directory that it needs to fill with compiled versions of libc etc.
	# https://emscripten.org/docs/tools_reference/emcc.html
	# By setting spawn_strategy=local, we can avoid recompiling all of this for every compilation
	# unit, by letting the cache be used (and not dropped from the sandbox), which gets expensive.
	# Local testing showed using the local strategy sped up a clean build from 9.5 minutes
	# to 1 minute. https://bazel.build/docs/user-manual#execution-strategy
	build:ck_release --config=release --spawn_strategy=local
	build:ck_debug --config=debug --spawn_strategy=local

	# We only want to enforce IWYU on debug builds because we have some things that are only
	# necessary to include in debug mode (e.g. SkDEBUGCODE), but very rarely something that is
	# only needed in release mode. Thus our C++ debug includes should be a superset of the
	# release includes.
	build:enforce_iwyu --features=skia_enforce_iwyu --cc_output_directory_tag=iwyu --compilation_mode=dbg