As a follow-up to https://skia-review.googlesource.com/c/skia/+/476219,
this sketches out how we can maybe use cc_library for the things
in //modules to make sure something in //src doesn't depend on
anything in //modules, for example.
The following succeeds:
bazel build //modules/skparagraph:skparagraph --config=clang \
--shaper_backend=harfbuzz_shaper --with_icu
As does `make bazel_canvaskit_debug` in //modules/canvaskit
Suggested Review Order:
- third_party/BUILD.bazel for ICU and harfbuzz rules. Pay
special attention to the genrules used to call the python
script for turning the icu .dat file into .S or .cpp.
- bazelrc and bazel/ for new flags and defines that control
use of ICU and harfbuzz. Unlike GN, with the public_defines
that get added in automatically if icu or harfbuzz is
depended upon, we need to set the defines at the top level.
This necessity might go away if we change the atoms to
depend on //modules/skshaper, which could define that flag.
- Top level BUILD.bazel files in //modules/skparagraph,
//modules/skshaper, //modules/skunicode, //modules/canvaskit
- All other .bazel file changes are automatic.
Bug: skia:12541
Change-Id: I38a9e0a9261d7e142eeb271c2ddb23f362f91473
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/478116
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
Importantly, this adds options for encoding using
certain codecs, not just decoding.
Change-Id: I4a610ebf985b67d4545c71b3f3eed4c7807e6a26
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/472277
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
This re-works src/ports/BUILD.bazel to work like our other
BUILD files, i.e. one rule "srcs" that brings in the necessary
private filegroups.
To work around an abort with LLVM [1], we have to go back to an
earlier version of emscripten (temporarily?).
Future work should look at using transitions [2] to allow various
executables (e.g. CanvasKit, DM) to set their own set of Bazel
flags, w/o the build invokers having to specify them.
These transitions might be able to handle more complex cases
that we currently use if statements in GN to deal with.
The Freetype build rule was created by taking the BUILD.gn
rule, adding in all the sources listed there and then playing
compile-whack-a-mole to add in all the headers and included
.c files.
Suggested Review Order:
- third_party/BUILD.bazel to see freetype build rules
- bazel/common_config_settings/ to see treatment of fontmgr
like codecs (many possible) and fontmgr_factory (only one).
- src/ports/BUILD.bazel
- BUILD.bazel
- modules/canvaskit/BUILD.bazel. Take note of the gen_rule that
calls tools/embed_resources.py to produce the .cpp file
containing the embedded font data.
- Everything else.
[1] https://github.com/emscripten-core/emscripten/issues/15528
[2] https://github.com/bazelbuild/examples/tree/main/rules/starlark_configurations/cc_binary_selectable_copts
Bug: skia:12541
Change-Id: I08dab82a901d80507007b354ca20cbfad2c2388f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/471636
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
This ports the third_party BUILD.gn files related to codecs
(with a best-effort on arm/SIMD stuff). This includes:
- libpng
- libjpeg-turbo
- libwebp
- wuffs (gif)
- libgifcodec
- dng_sdk and piex (raw codec)
This expands the string_flag_with_values macro to allow
multiple values to be set at once. This was added in Bazel 5.0.0,
however the latest pre-release version of that has a bug [1]
which slows down compilation dramatically. This was fixed at
ToT, but not released. As a result, I started using the Bazel
6 pre-release (via bazelisk).
The macro select_multi makes writing select() where multiple
elements could be on possible/easier.
One can try compiling certain codecs by running:
bazel build :skia-core --config clang --include_codec=raw_codec --include_codec=png_codec
Suggested Review Order:
- bazel/macros.bzl
- bazel/common_config_settings/defs.bzl and its BUILD.bazel
to see how the codec options are defined.
- BUILD.bazel to see how the codec settings are used.
- src/codec/BUILD.bazel to see the inclusion of Skia files to
deal with specific codecs.
- third_party/BUILD.bazel (while referencing the corresponding
BUILD.gn files, such as third_party/libwebp/BUILD.gn)
- Everything else.
Change-Id: I797375a35fa345d9835e7b2a2ab23371c45953c3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/469456
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
These rules can be used to build our GMs on WASM+WebGL and
libskia.a with just the CPU backend (and most other features
turned off).
This can be done with the following commands:
- bazel build //modules/canvaskit:gm-bindings-wasm --gpu_backend=gl_backend --with_gl_standard=webgl_standard
- bazel build :skia-core --config clang
This pivots slightly from http://review.skia.org/463517
by using config_settings [1] instead of platforms for
the optional features that we control. This pivot was
suggested in [2]
We have BUILD.bazel files in many of the subdirectories
that specify filegroups for the appropriate files. In
an effort to make //BUILD.bazel more readable, it is
the responsibility of these subfolders to deal with
conditionally including certain .h or .cpp files.
This is done using select statements and config_settings
or platform constraints as necessary.
For example, src/gpu/BUILD.bazel will different private
filegroups for each of the supported gpu backends [3]
and a more-visible filegroup called "srcs" that has
the right selection of the private files to be used
for compilation.
An effort has been made to avoid using glob() in our
BUILD.bazel files. These file lists were made by using
`ls -1` and some regex to add in quotes. We might want
to make a helper script to assist with that, if necessary.
To specify which options we have, the settings in
//bazel/common_config_settings/BUILD.bazel have been
redesigned. They make use of a macro `string_flag_with_values`
that removes the boilerplate. Patchset 36 shows what the
file looks like w/o the macro.
The top level BUILD.bazel file will still need to use
some logic to handle defines, because local_defines is
a list of strings, not a list of labels [4].
Suggested Review Order:
- WORKSPACE.bazel to see the new dependencies on the
emsdk toolchain and bazel_skylib
- bazel/common_config_settings/* to see the few settings
defined (we have more to define, see BUILD.gn and
//gn/skia.gni for ideas)
- BUILD.bazel to see the "skia-core" cc_library rule.
See also "gms" and "tests"
- modules/canvaskit/BUILD.bazel to see the use of
the emscripten "wasm_cc_binary" rule, which depends
on the "skia-core", "gms", and "tests" rule. Note that
it only builds some of the gms as a proof of concept.
- The other BUILD.bazel files. Some of these are not
platform or feature dependent (e.g. pathops). Others
are (e.g. gpu).
- All other files.
[1] https://docs.bazel.build/versions/4.2.1/skylark/config.html#user-defined-build-settings
[2] https://github.com/emscripten-core/emsdk/pull/920
[3] In this CL, that's just the webgl one.
[4] https://docs.bazel.build/versions/main/be/c-cpp.html#cc_library.local_defines
Change-Id: Ieecf9c106d5e3a6ae97d13d66be06b4b3c207089
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/458637
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
Owners-Override: Kevin Lubick <kjlubick@google.com>
This can successfully build a C library:
bazel build --config=clang //third_party:libpng
This can build and run a statically-linked executable:
bazel test --config=clang //:bazel_test
For more verbose compile and linking output, add the
`--features diagnostic`
flag to a Bazel command (see _make_diagnostic_flags() in
toolchain/clang_toolchain_config.bzl. Similarly, a
`--features print_search_dirs` can be used to show where
clang is looking for libraries etc to link against.
These features are made available for easier debugging.
Suggested review order:
- Read https://docs.bazel.build/versions/4.2.1/tutorial/cc-toolchain-config.html
if unfamiliar with setting up C++ toolchains in Bazel
- .bazelrc and WORKSPACE.bazel that configure use and download
of the toolchain (Clang 13, musl 1.2.2)
- toolchain/build_toolchain.bzl which downloads and assembles
the toolchain (w/o installing anything on the host machine)
- toolchain/BUILD.bazel and toolchain/*trampoline.sh to see
the setup of the toolchain rules.
- toolchain/clang_toolchain_config.bzl to see the configuration
of the toolchain. Pay special attention to the various
command line flags that are set.
- See that tools/bazel_test.cc has made a new home in
experimental/bazel_test/bazel_test.cpp, with a companion
BUILD.bazel. Note the addition of some function calls
that test use of the C++ standard library.
The number being used to test the PNG library is the latest
and greatest that verifies we are compiling the one brought
in via DEPS (and not a local one).
- third_party/* to see how png (and its dependent zlib) have
been built. Pay special attention to the musl_compat hack
to fix static linking (any idea what the real cause is?)
- //BUILD.bazel to see definition of the bazel_test executable.
Change-Id: I7b0922d0d45cb9be8df2fd5fa5a1f48492654d5f
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/461178
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
