Now that LLVM 12 has been released we no longer have any need to
bootstrap LLVM to get the desired featureset. LLVM 12 is available
widely, including in Homebrew across multiple platforms and in the
GitHub action runners.
Sadly, the Linux distribution builds of LLVM-12 are largely broken and
not as useful for us. The Homebrew Linux install was also broken
originally, but I've worked extensively with the Homebrew folks to get
the Linux install into a really good shape. It should now work reliably.
There are two primary bugs in Linux LLVM packages that need to be fixed
before we can just use them:
- https://bugs.llvm.org/show_bug.cgi?id=43604
- https://bugs.llvm.org/show_bug.cgi?id=46321
Once those are addressed and point releases with the fixes widely
available we can further simplify things.
Even with the need to use Homebrew installs, using the released LLVM has
the extra advantage of making it easy to properly support Darwin ARM and
I've added that configuration so that I can test things there.
Last but not least, this will significantly shrink our build outputs
which should allow building much more in continuous integration on
GitHub actions without exceeding the action cache size limits. I've even
added several tweaks and adjustments to the compile and build flags to
improve the build performance and reduce the build output size.
Once this is landed and stable, we can consider adding the refactoring
tooling back to our CI.
One of the biggest downsides of this path is that our CI has to download
and install the LLVM toolchain from Homebrew on each run. This is pretty
slow (takes a couple of minutes). But it is a fixed overhead -- it won't
get worse over time. Eventually, we can either look at a much fancier
action configuration to avoid this or hopefully the Debian packages will
get updated and we can move back to those.
The bootstrapping has served us long enough at this point. We can
resurrect it if we ever find a compelling reason for breaking off of the
latest LLVM release as our host toolchain.
Co-authored-by: Jon Meow <46229924+jonmeow@users.noreply.github.com>
This matches the version on Ubuntu LTS and other OSes. The only problem
I found with it in our testing is that Bazel confusingly sets the locale
to use `LANG=en_US` by default which breaks UTF-8 support. We may need
to shift this on Windows, but this seems like a reasonable first step.
Co-authored-by: Jon Meow <46229924+jonmeow@users.noreply.github.com>
Notes versus what jsiek wrote:
- This adopts Bazel for building.
- System-local versions of bison/flex are used. I found https://github.com/jmillikin/rules_bison, but those print a lot of warnings (things like -Wsign-compare IIRC) which makes builds hard to read. Plus I think the underlying bison_cc_library rule didn't work, so this would really only get a hermetic bison/flex build (helpful, but didn't seem worth more time).
- I'm adding in a .bazeliskrc to push a somewhat more standard choice of bazel versions. I noticed I was getting unstable versions by default, possible Google-specific, but seemed good to include.
- The `-lpthread` kludge.
- Turn all of the examples into golden tests.
- Including adding a golden test rule.
- Fixed various style guide issues. For example:
- Fixing function names to be CamelCase instead of snake_case (https://google.github.io/styleguide/cppguide.html#Function_Names)
- Removed exception use (https://google.github.io/styleguide/cppguide.html#Exceptions)
- File name fixes (https://github.com/carbon-language/carbon-lang/blob/trunk/docs/project/cpp_style_guide.md#file-names)
- Dropped `using` of `std` names -- I believe this is preferred (maybe we should be explicit about this in the Carbon style guide)
- Switched `enum` uses to `enum class` for ease-of-identification.
- Spent some time breaking out files to hopefully be easier to read/edit pieces, and understand relations between structs.
- Added `code requires` to `syntax.ypp` to address include issues
Possibly other things -- but the fundamental structure is, I believe, unchanged. I put in the golden tests pretty early to ensure I wasn't mutating output/results.
Per chandlerc's comment:
First, this builds inside the Bazel tree rather than in the source
repository. This ensures we start in a clean directory each time the
repository rule is run again. We don't need to detect an existing build
with this, and it will only be rebuilt when the workspace file or the
repository rule implementation is changed. This can be forced by using:
```
bazel sync --configure
```
Second, we use an implicit dependency on the `WORKSPACE` file to locate
the workspace directory automatically, and the `HEAD` file from the
`llvm-project` submodule to trigger a rebuild if the submodule is
updated.
Third, teach the CMake script to try to use a system-installed `clang`
if installed and not overridden by the `CC` environment variable. This
is very different from the prior logic -- this is only used with the
CMake build, and so should work with any system C++ compiler that can
build Clang and LLVM.
Lastly, this tweaks the CMake options to tune this build given that we
now fully control it and it will only be used in this context. This
still results in a 1.5gb build for me. =/ But its as small as I can make
it really. It's a frustrating long list, but I couldn't find a more
brief way of representing this.
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
- bazel/bazelisk because it's kinda needed
- buildifier per #236
- Clang/LLVM I know a number of people are familiar with, but I wasn't...
- `go get` and `pip` because it's feeling more and more appropriate to separate out package managers vs other tools
Adopts new copyright and markdown toc checks.
The new toc check generates the toc header, so that's why all the md files changed (this had felt better to me for the long-term, more auto-generated content)
We're running into issues with md handlers that expect this kind of 4-space indent. It should be cross-compatible with GH, so switch, even though it feels a little churny.
Manual edits are to:
- .prettierrc.yaml:
- rename from .prettierrc
- add tabWidth (primary change)
- add trailingComma (fix vimPrettier skew)
- contribution_tools.md: Fix remarks about .prettierrc.yaml
- pre-commit-toc.js: indent, bullets
- pre-commit-proposal-list.py: indent of output
The rest is the result of `pre-commit run --all-files`
Unfortunately this'll probably depend on the change being propagated into PR branches, so I wouldn't be surprised if we see regressions for a bit. We'll also need to nudge people to update .vimrc's. Hopefully the pre-commit GH action helps catch issues.
This catches some common spelling errors, but is *not* an exhaustive spell-checker. The only false positive is "rouge" in Gemfile.lock, which is why I'm excluding that file.
True positives are in the change, and it does catch the "langauge" typo I keep making, which zygoloid fixed for me in a few spots. False negatives are:
- virmc
- Announcemented
- propsal
For comparison:
- cspell (https://www.npmjs.com/package/cspell) is too aggressive and has a small dictionary
- Caught the false negatives, but many false positives, including 'LLVM', 'roadmap', 'Carruth'
- https://github.com/lorenzwalthert/precommit has a spellcheck, but config looks ruby-specific
Added here:
- .pre-commit-config.yaml
- docs/project/contribution_tools.md
- src/scripts/pre-commit-toc.js
- CONTRIBUTING.md
- proposals/* (just to switch TOC formats)
The rest consists of auto-generated fixes.
The switch from doctoc to markdown-toc is because doctoc wants to put a TOC in every file, whereas markdown-toc only does it if you have an insertion point.
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Jon Meow
Chandler CarruthandJon Meow
Dave Abrahams
Matt Godbolt
Richard Smith