This shouldn't change any functionality, but simplifies (significantly)
the logic in the installed toolchain, and also provides a better
conceptual balance between these.
I've tried to minimize the changes beyond a pure refactoring, but it was
a bit tricky to get everything working so some things have been mixed
in...
Assisted-by: Antigravity with Gemini
This reverts commit 4babfdbf22.
This was a stacked PR that was merged by accident, losing the commit and
description of the base change. Reverting and will re-land
independently.
Without this, basic `bazel test //...` style wildcards would build
a bunch of extra configurations because of gaps excluding things. With
this, the action count of a normal build should be much more reasonable.
The switch from `target_compatible_with` to tagging is based on looking
at what ends up being most idiomatic and easiest -- trying to articulate
the complex and convoluted compatible with restrictions that would avoid
extraneous build configurations was really painful and this seems much
simpler and easier to deploy in a systematic way.
While here, also change the name of a rule that confused me to no end
while debugging this -- the rule that installs a `.bzl` file that
happens to be spelled `carbon_runtimes` is very different from all of
the other "installed carbon runtimes" kind of things in the tree. Adding
the file extension helps make that (much) more obvious.
Assisted-by: Antigravity with Gemini
This worked correctly in the system Clang toolchain, but was not
configured correctly in the Carbon toolchains. The test is designed to
let us cover all of these.
Assisted-by: Antigravity with Gemini
The runtimes and bootstrap Bazel logic was previously built around
defining custom Bazel platforms constrained with `constraint_settings`.
The use of platforms added significant complexity, including the need to
"save" and "restore" the original platform, and other complexity
stemming from changing the platform as a whole.
This PR switches to use the simpler tool of build settings, and
`target_settings` on the toolchain rather than platform compatibility.
This remove the entire need to save and restore the platform, and also
generally simplifies things.
This PR also fixes some bugs in the bootstrap that were hidden by the
use of platforms, such as the need to carefully manage the different
inputs to the runtimes build so that generated inputs pick up the
correct exec configuration -- the exec transition happened to do this
"automatically", but it seems better to handle explicitly. And it cleans
up an extraneous copy of `carbon_runtimes.bzl` that snuck in somehow.
Assisted-by: Antigravity with Gemini
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
This also switches to a more Bazel-based install layout, skipping the
FHS-based synthetic layout. The FHS-based layout is still reconstructed
explicitly when building an installable tar-ball.
The biggest change is to configure the just-built install as a Bazel
toolchain, including allowing it to build its own runtime libraries as
native Bazel libraries. This removes the need for a monolithic runtimes
build, all of that code logic is removed.
This should also pave the way to using the just-built toolchain for
doing a full 3-stage bootstrap. Building the 2nd stage is included here
as it was a particularly effective way to test that the Bazel
integration was fully working. Adding a 3rd-stage check for stability is
future work, but should be pretty easy.
There is a down-side: this uses the busybox to do the runtimes
compilation, which means they will be re-built after ~any change to
Carbon. However, the integration with Bazel should largely pay for this,
and we can continue to factor the tests away from depending on built
runtimes in most cases.
Now that we're building and testing the runtimes more directly, this
surfaced a problem with the layout of runtimes on macOS that is fixed
here. All of the Darwin OSes use a custom layout for their resource
directory compared to other targets. We now model this in both the C++
built runtimes and the Bazel built runtimes.
Assisted-by: Gemini via Antigravity
This let's you point Bazel at an installed toolchain or download one of
our release archives. When you do, it will configure itself as a C++
Bazel toolchain. This toolchain works reasonably well, but doesn't cache
the C++ runtimes, and so linking is inefficient. The next step will be
to pivot the runtimes from the implicitly on-demand (which can't cache
when using a sandboxed build system like Bazel) to _explicit_ on-demand
runtimes directly with Bazel support.
I've included an example Bazel project that uses this and provides a
bunch of documentation and an example script that should let folks try
this out easily.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: David Blaikie <dblaikie@gmail.com>
Uses bazel 8 flags since there's the update in #4729. bazelisk was used
to generate the list of flags (see bazelrc comment). The overall
approach is trying to do our best to follow
https://bazel.build/release/backward-compatibility, in particular since
`--incompatible_strict_action_env` had come up (essentially just
adopting as much as we can now).
The default visibility changes in `carbon_rules/BUILD` and
`cc_toolchains/BUILD` files are for
`--incompatible_config_setting_private_default_visibility`. That's
enough for fastbuild, but we use tcmalloc in opt, and it has an issue.
In `clang_toolchain.BUILD` it's for
`--incompatible_check_visibility_for_toolchains`, even though
`rules_shell` then breaks on it. `manifest/defs.bzl` changes are for
`--incompatible_disable_target_default_provider_fields` which
`rules_pkg` breaks on. Even though these flags are off, I'm keeping the
changes since we should eventually enable the flags.
I'm still looking at the tree sitter rules due to the WORKSPACE issue,
but I think that needs more substantial work.
LLVM_SYMBOLIZER_PATH is required if `llvm-symbolizer` isn't in the developer's PATH. This sets it via bazel instead of having a developer handle it. I noticed this because the apt install of clang doesn't put llvm-symbolizer in the PATH.
I'd like to make this the default without putting it everywhere, but I don't see a way to do this intrinsically through [the toolchain](https://bazel.build/docs/cc-toolchain-config-reference), and the [rules_cc/defs.bzl](https://github.com/bazelbuild/rules_cc/blob/main/cc/defs.bzl) remains a thin wrapper around the native cc_binary.
Since I'm adding another env, it seems undesirable to have the macos asan workaround separate. As a consequence, this merges it in. Note bazel doesn't support merging a dict and a select, so it's also necessary to have the two env vars at least mildly aware there's something up (and this could get worse if we end up having more selects).
The Bazel bits are collected into a directory and given less confusing
names (I hope). Other than names, everything is a direct copy from the
toolchain repository without any edits.
A few files needed to be merged in:
- `.gitignore`
- `.pre-commit-config.yaml`
Subsequent commits will add relevant C++ infrastructure and then the
source code itself.
Chandler Carruth
Jon Ross-Perkins