bazel run //example:hello_world --config=clang
causes a window to open and draws a circle and a square.
Text to follow in a future CL.
To make this work, I had to get rid of musl and use glibc.
All the shared libraries (.so files) that were pre-built
and available for download (e.g. from https://packages.debian.org/bullseye/amd64/libgl1/download)
were compiled against glibc. When I tried to run a
program statically linked with musl and dynamically linked
against things using glibc, I got a segmentation fault
on things like calloc().
Initial attempts to use glibc had failed because it was thought
that the libc.so.6 file could only be referred to by absolute
path (and thus Bazel would not be happy about it). As it turns out,
that was simply a misconfiguration of the builtin_sysroot
parameter to cc_common.create_cc_toolchain_config_info
(see //toolchain/clang_toolchain_config.bzl). By setting that
to `external/clang_linux_amd64` and not
`external/clang_linux_amd64/usr`, the libc binary which had
been extracted to `external/clang_linux_amd64/lib/x86_64-linux-gnu`
was perfectly reachable from
`external/clang_linux_amd64/usr/usr/lib/x86_64-linux-gnu/libc.so`
To bring in the shared libraries to link against (e.g. X11, GL)
I made build_toolchain.bzl easier to modify in that we simply need
to add a debian download url and sha256 hash to a list (rather than
having to plumb this through via arguments).
Recommended Review Order:
- example/BUILD.bazel (not sure if we always want to set bare
link arguments like that or if we want to use "features" to
pass those along to the toolchain).
- tools/sk_app/BUILD.bazel to see initial cc_library for
wrapping sk_app code.
- toolchain/build_toolchain.bzl to see removal of musl and
new list of debs.
- toolchain/clang_toolchain_config.bzl (where use of the
no-canonical-prefixes was key to compilation success).
Notice also that we statically linked libc++ (I did not
have any shared libraries for it locally, so I guessed
a typical developer might not either).
- Rest of toolchain/ for trivial renames.
- bazel/Makefile to see extra docs on those targets and
a new target that compiles all the exes so far for a
quick way to test the build.
- third_party/BUILD.bazel and src/gpu/BUILD.bazel which have
non-generated changes. (all other BUILD.bazel files do).
- go.mod, which needed to update the infra repo version in
order to pick up http://review.skia.org/491736).
Change-Id: I8687bd227353040eca2dffa9465798d8bd395027
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/492117
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
To make the atomic rules a bit easier to work with, in many
of the folders, this adds in cc_library rules to group
together the sources from that folder (and subfolders
where prudent). We only needs sources because those atoms
should have their headers as deps.
One issue that was pointed out is that there is currently
no way to restrict the inclusion of certain packages,
a la, `gn check`. For example, there is no mechanism from
stopping a dev from adding
#include "modules/canvaskit/WasmCommon.h"
to something in //src/core (except circular dependencies).
We can probably address that using Bazel's visibility
rules as needed:
https://docs.bazel.build/versions/main/visibility.htmlhttps://docs.bazel.build/versions/main/be/functions.html#package_group
It is recommended to look at this CL patchset by patchset.
PS1: Update gazelle command to generate rules in more folders.
PS2: A few changes to make generation work better.
PS3: The result of running make generate in //bazel
PS4: Adding the rules to build sksllex, the simplest binary I
could find in the Skia repo.
PS5: Adding the rules to build skdiff, a more complex binary.
I tried a few approaches, but ended up gravitating back
towards the layout where we have each folder/package
group up the sources. I imagine at some point, we'll have
skdiff depend on skia_core or something, which will
have things like //src/core, //src/codecs, //src/pathops
all bundled together.
PS7: Added in the groupings of sources, similar to what we had
earlier. I liked these for readability. These helped fix
up the //:skia_core build, and by extension, the CanvasKit
build.
Change-Id: I3faa7c4e821c876b243617aacf0246efa524cbde
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/476219
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
This adds a simple go program to test the installed go
toolchain, and a Make rule to codify the arguments to
our gazelle binary, built with extensions.
I could not figure out how to get the .json file to work
with the gazelle() Bazel rule, but this works ok for now.
Bug: skia:12541
Change-Id: I5067b15c7518951aeb69559d3871799d3b5745f4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/475716
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
This uses the gazelle extension from
https://skia-review.googlesource.com/c/buildbot/+/473357
Review Tips:
- Ignore any changes to .h or .cpp files. Those have been
pulled out into their own CLs.
- Start with bazel/macros.bzl.
- Read the CL with the generation code, if you haven't already.
- Look at third_party/file_map_for_bazel.json.
- See experimental/bazel_test for an idea of how a cc_binary
would be made.
- Spot check one or two of the BUILD.bazel files.
This CL generates the "atomic" rules for src/, include/ and
modules/skshaper, as a starting point.
`bazel build --config clang //include/...` works
`bazel build --config clang //src/...` starts compiling,
(which verifies that the BUILD.bazel files are all valid),
but runs into errors because not all third_party deps have
been resolved, and there are some files missing from the
toolchain still (e.g. EGL headers).
Change-Id: Ib7e0fb0efdb9f08655f06cbc56e9bb4cf416294b
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/474240
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
This makes use of Bazel's pre-defined platforms
https://github.com/bazelbuild/platforms
and some of our own defined values (see
//bazel/common_config_settings/BUILD.bazel) to customize
the build rules.
I verified this by building bazel_test locally for
linux x64 as well as using the third_party deps for
a WASM build (using build files not seen in this CL).
Suggested Review Order:
- https://docs.bazel.build/versions/main/platforms.html if not
already familiar with Bazel Platforms
- third_party/BUILD.bazel to see that 1) all globs have
been removed and 2) select() targets various
platform constants or groups of constants to control
sources, headers, and local_defines.
- common_config_settings/ to see the groups of constraints
created, as well as new constraint_settings defined
(skdebug_impl)
- supported_combinations/ to see how we can define supported
sets of the constraint values (aka Bazel platforms).
I imagine expanding this more, so we might have platforms
named "linux_x64_emptyfontmgr_vulkan" or such.
- //BUILD.bazel and bazel_test.cpp to see use of SkDebugf.
- Everything else.
Change-Id: I49e4abdbcf7b76f0674efdbb1f53dc8823d110ee
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/463517
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>
