Commit Graph
237 Commits
Author SHA1 Message Date
josh11bandJosh L 4f2b3b644c Support jj workspaces in suggested jj abandon-untagged alias (#7222)
`@` refers to the current workspace's working copy, but if we want the
command to respect the working copies of other workspaces, we should use
`working_copies()` instead; see
https://docs.jj-vcs.dev/latest/revsets/#functions .

Also remove `all() &` while here, since it is always redundant.

Assisted-by: Google Antigravity

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2026-05-17 23:03:22 +00:00
Chandler Carruth 2047e08635 Update examples throughout the design for p7016 (#7200)
Also updates a few spots with some subtle aspects changed in
`lambdas.md` and `namespace_cleanliness.md`.

Assisted-by: Antigravity with Gemini
2026-05-13 18:42:55 +00:00
9fb0e4a7ae Add sufficiency of declaration to the information accumulation principle (#7179)
Adding to the information accumulation principle instead of creating new
principle #5990.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2026-05-08 22:38:34 +00:00
Jon Ross-Perkins cd6ab7ce8e Switch jj settings to 'jj config set' because of repo (#7007)
jj moved the repo config outside the repo. The config.toml might exist
as a symlink in older repos (probably migration), but not clean repos.
So, overall, just switching the advice setup to make it a bit more
robust with config locations.

Also adding "trunk" to the repo config.

Assisted-by: Google Antigravity with Gemini
2026-04-01 21:36:56 +00:00
Richard SmithandJon Ross-Perkins 5b7c908e8b Add documentation for setting up jj b a. (#6996)
This gives a setup where `jj b a` / `jj bookmark advance` can reliably
be used to advance a bookmark for a github pull request, without
advancing other bookmarks such as `trunk` or pointing the bookmark at an
empty commit.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2026-04-01 16:46:14 +00:00
Chandler Carruth 2bbcfa5e1a Remove ASan from the default build mode (#7003)
Also increases the default optimization to `-Og` which is likely to give
faster turn-around time which is what we want to optimize for here. This
should also _substantially_ shrink binary sizes, etc.

ASan is still available via `--config=asan`, and is added to the CI
infrastructure. However, my current thought is to only run it after push
rather than in PRs and in the merge queue.
2026-04-01 16:45:53 +00:00
Nicholas Bishop 6ac561afe9 Add "Fixing conflicts with trunk" to code_review.md (#6889) 2026-03-11 19:30:20 +00:00
Jon Ross-Perkins 6786edd6ff Update action versions (#6848)
In addition to the general updates, this switches to a required python
3.10 for pre-commit (3.9 is losing support from black).

Note endpoints for build actions are expanding significantly: see
https://app.stepsecurity.io/github/carbon-language/carbon-lang/actions/runs/22779388360?tab=recommendations&jobId=66080970460
for example, I think just the sources are being increased as a
side-effect of updates (and possibly also things not performing as well
as they should have before).

Similarly allowing sudo in pre-commit because it was actually causing
errors in part of build setup, which used sudo to remove files.

Assisted-by: Google Antigravity with Gemini
2026-03-06 22:19:44 +00:00
Jon Ross-PerkinsandRichard Smith 2327b62b5f Add jj and AI notes to contribution tools (#6841)
Giving both of these their own sections under optional tools because I'm
mainly doing this to share example configs.

Assisted-by: Google Antigravity with Gemini

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2026-03-06 16:13:00 +00:00
Richard Smith bf6f21b8e9 Add a GEMINI.md. (#6838)
Assisted-by: Gemini 3 Pro via Antigravity
2026-03-05 19:56:13 +00:00
d8adcf93f5 Consolidate debugging documentation. (#6596)
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
2026-01-14 19:00:46 +00:00
Jon Ross-PerkinsandDana Jansens fb58a41b11 Add a note about iterative coding style (#6528)
Adding the note about recursion because it occasionally comes up, and
I'm thinking it'd be helpful to document why we prefer iterative
algorithms.

Also moves a few long style points to headers so that they're easier to
link (I wasn't sure it makes sense to do to all of "syntax and
formatting", but either way what's remaining is shorter if that _is_
linked for reference).

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
2025-12-19 21:00:14 +00:00
Jon Ross-Perkins 31d88633e3 Add some autoassigner notes (#6154) 2025-10-01 20:35:14 +00:00
Geoff RomerandRichard Smith c713279a3d Keep design documents current (#5606)
Require language design proposals to either update the design documents
to
reflect the proposed changes, or add "TODO" comments to mark where those
changes
will be needed, with links back to the proposal. This is intended to
ensure that
the design documentation accurately informs readers about the current
language
design, without excessively burdening the proposal process.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-10-01 20:12:05 +00:00
Jon Ross-PerkinsandDana Jansens f27ccbf76e Add CODEOWNERS for review assignment (#6153)
This disables the autoassign action so that the codeowners approach can
be tested without interference.

Trying this out because it might be a path for vacation handling. See
[GitHub
docs](https://docs.github.com/en/organizations/organizing-members-into-teams/managing-code-review-settings-for-your-team)
and
[#infra](https://discord.com/channels/655572317891461132/707150492370862090/1422985757311635620)

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
2025-10-01 17:50:53 +00:00
David Blaikie 7bfd26b06e Disallow using "request changes" as it's proven problematic (#6121)
I wasn't sure exactly in what way it was problematic, so I was a bit
vague in the justification (though justifications aren't generally
needed/provided here anyway - so I'm not sure it'd be net helpful to add
one anyway).
2025-09-24 21:26:07 +00:00
223d0397c0 Updating Carbon's safety strategy (#5914)
Carbon is accelerating and adjusting its safety strategy, specifically
to flesh out its memory safety strategy and reflect simplifying
developments in the safety space.

This proposal replaces the previous directional safety strategy with a
new concrete and updated framework for the safety design. It includes a
specific framework for memory safety, simplified build modes, specific
"safety modes", and terminology.

This proposal also provides a _directional_ suggestion for temporal and
data-race safety specifically.

In addition to fully building out the above directional component, there
are several other aspects of our safety design that will follow in
subsequent proposals. The hope is to establish the initial framework
here.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Mike Forster <michael@forster.pro>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-08-20 23:31:30 +00:00
Dana JansensandJon Ross-Perkins 5dc299f58b Note we are using Clang 16+ in the contribution tools docs (#5861)
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2025-07-28 18:25:04 +00:00
Dana Jansens 13e2268783 Add a dump command in lldb for dumping from ids (#5824)
The command is:
```
dump <context> [<ID>|<TYPE><ID>|<TYPE> <ID>|-- <ID>]

TYPE can be "inst", "entity_name", etc.
```

This saves a lot of typing of `SemIR::MakeInstId()` in a debugger, and
allows copy-pasting ids from dump output, as they take the form
`inst33`, etc.
2025-07-28 17:14:37 +00:00
Geoff Romer 12fbf9c9c2 Progressive disclosure principle (#5661)
This proposal codifies our preference for designs that support
"progressive
disclosure", meaning that programmers can ignore a given language
concept (or
even be unaware of it) until it is directly relevant to the task they're
doing.
2025-06-30 19:02:01 +00:00
Chandler CarruthandDana Jansens 9a4a9a9730 Introduce a benchmark running script (#5706)
This script runs benchmarks written using Google Benchmark repeatedly,
and collects the results from JSON to render them nicely and provide
statistical information across the runs.

Because this runs the binaries repeatedly, this can help account for
run-to-run variations that are pervasive in many of Carbon's benchmarks,
such as ASLR and other process-specific differences.

It's most basic mode runs a benchmark multiple times and shows both
median and confidence intervals.

It also supports two comparison modes:

1) Regular expressions can be provided that describe collections of
   related benchmarks where one is the "main" benchmark and the others
   are comparable. For example, Carbon's data structure vs. data
   structures from LLVM or Abseil. These will be rendered with the main
   benchmark first, followed by a comparison relative to a "baseline" of
   each comparable benchmark.

2) A baseline benchmark binary, and potentially different command line
   flags, can be provided to run two benchmark binaries and compute
   a comparison for each benchmark within them.

Across all of these, the script works to present the best text UI it can
in the console. I may have gotten a bit obsessed with rendering the
benchmark results in a way that is really pretty. There are lots of
fancy color coding and progress bars, etc., when run in in the terminal.

For the basic mode without any comparisons, the results look like:

```
Computing statistically significant deltas only wherethe P-value < 𝛂 of 0.05
Metric key:
   BenchmarkName...  <median> ± <% at 95th conf>

 Benchmark                                             ┃        CPU Time         ┃    bytes_per_second
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━
 BM_LatencyHash<RandValues<uint8_t>, CarbonHashBench>. │    3.051 ns ±   2.721%  │  327.8   M ±   2.765%
 BM_LatencyHash<RandValues<uint8_t>, AbseilHashBench>. │    3.395 ns ±   4.377%  │  294.6   M ±   4.572%
 BM_LatencyHash<RandValues<uint8_t>, LLVMHashBench>... │    6.125 ns ±   2.662%  │  163.3   M ±   2.726%
 BM_LatencyHash<RandValues<uint16_t>, CarbonHashBench> │    3.105 ns ±   3.947%  │  644.1   M ±   4.109%
 BM_LatencyHash<RandValues<uint16_t>, AbseilHashBench> │    3.433 ns ±   4.308%  │  582.6   M ±   4.502%
 BM_LatencyHash<RandValues<uint16_t>, LLVMHashBench>.. │    6.127 ns ±   2.540%  │  326.5   M ±   2.587%
 BM_LatencyHash<RandValues<uint32_t>, CarbonHashBench> │    3.082 ns ±   2.846%  │    1.298 G ±   2.923%
 BM_LatencyHash<RandValues<uint32_t>, AbseilHashBench> │    3.401 ns ±   3.611%  │    1.176 G ±   3.739%
 BM_LatencyHash<RandValues<uint32_t>, LLVMHashBench>.. │    6.209 ns ±   4.064%  │  644.3   M ±   4.236%
 BM_LatencyHash<RandValues<uint64_t>, CarbonHashBench> │    3.122 ns ±   2.871%  │    2.563 G ±   2.956%
 BM_LatencyHash<RandValues<uint64_t>, AbseilHashBench> │    3.426 ns ±   2.811%  │    2.335 G ±   2.892%
 BM_LatencyHash<RandValues<uint64_t>, LLVMHashBench>.. │    6.497 ns ±   3.081%  │    1.231 G ±   3.179%
```

For the first comparison mode on one of Carbon's benchmarks, the results
look like:

```
Computing statistically significant deltas only wherethe P-value < 𝛂 of 0.05
Metric key:
   BenchmarkName...    <median> ± <% at 95th conf>
     vs Comparable: 👍 <delta>    p=<U-test P-value>
                       <median> ± <% at 95th conf>

 Benchmark                                             ┃          CPU Time          ┃     bytes_per_second
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━
 BM_LatencyHash<RandValues<uint8_t>, CarbonHashBench>. │      3.037 ns ±   1.781%   │    329.2   M ±   1.813%
                                            vs Abseil: │ 👍  -8.200%     p=0.000183 │ 👍   8.933%    p=0.000183
                                                       │      3.309 ns ±   2.064%   │    302.2   M ±   2.022%
                                              vs LLVM: │ 👍 -49.401%     p=0.000183 │ 👍  97.632%    p=0.000183
                                                       │      6.003 ns ±   1.502%   │    166.6   M ±   1.480%
                                                       │                            │
 BM_LatencyHash<RandValues<uint16_t>, CarbonHashBench> │      3.026 ns ±   1.816%   │    661     M ±   1.784%
                                            vs Abseil: │ 👍  -8.599%     p=0.000183 │ 👍   9.408%    p=0.000183
                                                       │      3.311 ns ±   1.873%   │    604.1   M ±   1.839%
                                              vs LLVM: │ 👍 -49.829%     p=0.000183 │ 👍  99.319%    p=0.000183
                                                       │      6.031 ns ±   2.806%   │    331.6   M ±   2.730%
                                                       │                            │
 BM_LatencyHash<RandValues<uint32_t>, CarbonHashBench> │      3.017 ns ±   2.696%   │      1.326 G ±   2.625%
                                            vs Abseil: │ 👍  -9.754%     p=0.000183 │ 👍  10.808%    p=0.000183
                                                       │      3.344 ns ±   1.537%   │      1.196 G ±   1.514%
                                              vs LLVM: │ 👍 -49.857%     p=0.000183 │ 👍  99.427%    p=0.000183
                                                       │      6.018 ns ±   3.269%   │    664.7   M ±   3.167%
                                                       │                            │
 BM_LatencyHash<RandValues<uint64_t>, CarbonHashBench> │      3.025 ns ±   3.395%   │      2.644 G ±   3.284%
                                            vs Abseil: │ 👍  -9.812%     p=0.000183 │ 👍  10.879%    p=0.000183
                                                       │      3.354 ns ±   2.640%   │      2.385 G ±   2.572%
                                              vs LLVM: │ 👍   0.476x     p=0.000183 │ 👍   2.101x    p=0.000183
                                                       │      6.357 ns ±   2.477%   │      1.258 G ±   2.418%
                                                       │                            │
```

For the second mode, in this case comparing a baseline build with `-Oz`
vs an experiment with `-Os`, the results look like:

```
Computing statistically significant deltas only wherethe P-value < 𝛂 of 0.05
Metric key:
   BenchmarkName... 👍 <delta>    p=<U-test P-value>
          baseline:    <median> ± <% at 95th conf>
        experiment:    <median> ± <% at 95th conf>

 Benchmark                                                                  ┃          CPU Time          ┃     bytes_per_second
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━
 BM_LatencyHash<RandValues<std::pair<uint32_t, uint32_t>>, CarbonHashBench> │ 👍 -35.870%     p=0.000557 │ 👍  55.930%    p=0.000557
                                                                  baseline: │      5.704 ns ±   1.877%   │      1.403 G ±   1.911%
                                                                experiment: │      3.658 ns ±   4.209%   │      2.187 G ±   4.039%
                                                                            │                            │
 BM_LatencyHash<RandValues<std::pair<uint32_t, uint64_t>>, CarbonHashBench> │ 👍 -19.475%     p=0.00119  │ 👍  24.186%    p=0.00119
                                                                  baseline: │      4.974 ns ±   3.029%   │      3.217 G ±   3.124%
                                                                experiment: │      4.005 ns ±   4.297%   │      3.995 G ±   4.120%
                                                                            │                            │
 BM_LatencyHash<RandValues<std::pair<uint32_t, int*>>, CarbonHashBench>.... │ 👍 -11.740%     p=0.00153  │ 👍  13.302%    p=0.00153
                                                                  baseline: │      4.634 ns ±   3.433%   │      3.453 G ±   3.555%
                                                                experiment: │      4.09  ns ±   2.999%   │      3.912 G ±   2.911%
                                                                            │                            │
```

The script itself uses a new tool for managing dependencies called `uv`:
https://docs.astral.sh/uv/ This tool allows for the script to contain an
inline set of dependencies that will be installed and cached for
subsequent runs. This seemed particularly important as dependencies like
SciPy and NumPy can be particularly difficult to manager or keep
installed in other ways, but are essential to this scripts statistical
analysis. So far, the `uv` system has been working remarkably well for
me and been a relatively pleasant experience on the whole.

I have included as much of the Python dependencies as have good type
information into the MyPy configuration to get good type checking in
pre-commit however.

Last but not least, this has been a pet project of mine for a quite a
while and so may be a bit rough around the edges as I added and tweaked
functionality based on specific benchmarks I was looking at. It feels
like its gotten useful enough to contribute somewhere, but totally open
to any refactoring or improvements needed. I tried to take a few passes
over it to organize and document the code before sending it, but I'm
sure there are still some things that could use improvement.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
2025-06-24 12:47:32 +00:00
Dana Jansens 4a96799e1f Document our practices around using auto and naming variable types (#5663)
We use `auto` for most local variables, and we put the type name into
the variable name in common cases, especially for our ID types.

This was discussed in `#style`:
https://discord.com/channels/655572317891461132/821113559755784242/1380091326900469801
2025-06-18 14:10:01 +00:00
Jon Ross-Perkins 94d4ba682d Remove docker and devcontainer as unused (#5500)
As far as I'm aware, the the devcontainers aren't in frequent use, which
is why they fall out of date. Comparing with
https://github.com/llvm/llvm-project/, I don't see devcontainer configs
maintained as part of llvm
(https://github.com/llvm/llvm-project/issues?q=devcontainer doesn't have
much either) so I think we should trim these instead of investing in
maintenance.

These configs aren't being maintained. In the docker configs, note `RUN
bazel build //explorer` is broken. Also, #5496 noted the clang version
is out of date.

Closes #5496
2025-05-20 00:24:19 +00:00
Dana JansensandJon Ross-Perkins f5e69734d9 Bump clang version to 19 (#5440)
The version of clangd/clang-tidy on developer machines has slowly
diverged from the one on the CI builders, which is causing a slowly
increasing amount of pain as clang-tidy CI runs fail (incorrectly) over
things that a newer clangd/clang-tidy was perfectly fine with locally.
This bumps the Clang version used in the ubuntu builders to 19, which is
the most recent in Debian stable.

We use https://apt.llvm.org instead of LLVM's GitHub releases
(https://github.com/llvm/llvm-project/releases) as the former more
reliably has packages for newer Clang/LLVM versions on x64. The
community-build releases binaries on LLVM's GitHub have stopped
including Ubuntu packages that match the GitHub x64 Ubuntu workers for
some time (for at least the 18 and 19 releases).

By moving to apt.llvm.org packages we only download and install the
headers and libraries needed for development, rather than every output
of building llvm, which is much faster and saves lots of disk space. We
also remove the system installations of other versions of clang/llvm so
we should end up using negative disk space. We can no longer easily
cache the installation but apt.llvm.org is a reliable end point.

We bump the ubuntu image version for the github workers to 24.04, as
apt.llvm.org has stopped building images for 22.10 in 2022 at its end of
life.

The `pre_commit` workflow disabled sudo unlike the other workflows that
install Clang/LLVM, including the `clang-tidy` workflow (which is also
run on `pull_request`). We bring it into alignment with the other
workflows so that we can install the llvm packages. And we lock its
ubuntu image to 24.04 so that it can be moved in lockstep with the other
workflows that depend on Clang/LLVM.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2025-05-12 15:12:53 +00:00
Dana Jansens c3e112e664 Document and configure running lldb from the command line (#5324)
The docs explain that you must use `--local-lldbinit` in the command
line, and include an example of how to run a file_test under lldb from
the command line.

This PR includes `.lldbinit` file and `lldbinit.py` file which set up
our default options, copied from the VSCode launcher.

The instructions include settin the `max-string-summary-length`, and we
include this in the vscode launcher for lldb, as printing `Dump()`
output can easily get truncated otherwise when printing an InstBlockId.
2025-04-17 21:18:25 +00:00
Jon Ross-Perkins d6b6ba17fa Update pip3 mentions to pipx (#5065)
Install advice already says pipx.
2025-03-05 03:12:55 +00:00
Jon Ross-PerkinsandDana Jansens 467e510d40 Document abbreviation style things (#4996)
We had a long discussion of this, so trying to document what seems to be
the conclusion... and also clean up the exceptions that I could find.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
2025-02-27 02:13:17 +00:00
Chandler CarruthandRichard Smith b636065f53 Safety milestones and a 2025 roadmap (#4880)
We propose updating our milestones to accelerate design and
implementation of
memory safety in Carbon, and a roadmap for 2025 reflecting this change.
We also
provide a retrospective for 2024's progress.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-02-12 02:23:46 +00:00
Jon Ross-Perkins 2fef1cb713 Switch to trailing returns in toolchain and related code. (#4919)
Also makes the style guide explicitly comment on void, but this was the
intent IIRC because it matches Carbon's `-> ()` (and "always" versus
"except for void", which we definitely went back and forth on).

Includes adjusting function pointers, which I definitely forget this
syntax works sometimes.

Excludes utils/tree_sitter/src/scanner.c because it claims to be C, but
really we should probably fix that to be cpp.
2025-02-11 18:11:14 +00:00
Jon Ross-Perkins d005ac034a Add notes about PR labels (#4913)
Add a code review note for PRs. Background discussion of NFC happened [a
month
ago](https://docs.google.com/document/d/1Iut5f2TQBrtBNIduF4vJYOKfw7MbS8xH_J01_Q4e6Rk/edit?resourcekey=0-mc_vh5UzrzXfU4kO-3tOjA&tab=t.0#heading=h.brv2irjg39vf),
it just slipped my mind to update docs.
2025-02-07 22:13:19 +00:00
Richard SmithandChandler Carruth e257051612 No predeclared identifiers, Core is a keyword (#4864)
Introduce a principle that the Carbon language should not encroach on
the
developer's namespace. Satisfy this principle by making `Core` a
keyword.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2025-02-01 03:03:30 +00:00
Jon Ross-Perkins e348119feb Update a few faq questions which are showing their age (#4813)
Struck me I hadn't looked through this recently, although it feels it's
mostly held together.
2025-01-16 01:27:42 +00:00
Jon Ross-Perkins ccf51cef23 Update to bazel 8.0.0 (#4729)
This updates to bazel 8.0.0, also updating bazel mod deps and tools to
make that function. The release is a couple weeks old, and we haven't
updated in a while, and it's a major release. Note it includes some
incompatible flag flips that this is trying to update with respect to.
I'll try generally enabling incompatible support separately.

The most visible bazel behavior change here will be the change from `~`
to `+` in repo path names. (If you're curious,
https://github.com/bazelbuild/bazel/issues/23127 indicates this fixes a
Windows performance issue)

Note that this is building on top of both the action env update in #4728
(which got me started down this path) and the proto removal in #4731
(which would add significant work to this update). Only the commit
starting at "Work towards bazel 8.0.0" is specifically part of this PR.
2025-01-06 23:50:12 +00:00
Chandler CarruthandJon Ross-Perkins 13502b7c89 Replace #4505 with a different set of workarounds (#4527)
This restores the symlinks for the installation, but teaches the busybox
info search to look for a relative path to the busybox binary itself
before walking through symlinks. This let's it find the tree structure
when directly invoking `prefix_root/bin/carbon` or similar, either
inside of a Bazel rule or from the command line, and mirrors how we
expect the installed tree to look. This works even when Bazel resolves
the symlink target fully, and potentially to something nonsensical like
a CAS file.

In order to make a convenient Bazel target that can be used with `bazel
run //toolchain`, this adds an override to explicitly set the desired
argv[0] to use when selecting a mode for the busybox and a busybox
binary. Currently, the workaround uses an environment variable because
that required the least amount of plumbing, and seems a useful override
mechanism generally, but I'm open to other approaches.

This should allow a few things to work a bit more nicely:
- It should handle sibling symlinks like `clang++` to `clang` or
  `ld.lld` to `lld`, where that symlink in turn points at the busybox.
  We want to use *initial* `argv[0]` value to select the mode there.
- It avoids bouncing through Python (or other subprocesses) when
  invoking the `carbon` binary in Bazel rules, which will be nice for
  building the example code and benchmarking.

It does come at a cost of removing one feature: the initial symlink
can't be some unrelated alias like `my_carbon_symlink` -- we expect the
*first* argv[0] name to have the meaningful filename for selecting
a busybox mode.

It also trades the complexity of the Python script for some complexity
in the busybox search in order to look for a relative `carbon-busybox`
binary. On the whole, I think that tradeoff is worthwhile, but it isn't
free.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-12-20 00:33:29 +00:00
Jon Ross-Perkins ee4746c41c Add documentation for running GDB and LLDB (#4710)
After lots of fidgeting, LLDB seems to work. Not sure how reliable this
will be though -- fission seems a little hit and miss.
2024-12-19 00:32:25 +00:00
Jon Ross-Perkins cb4686bf21 Enable misc-non-private-member-variables-in-classes and adjust style to match (#4702)
Pursuant to discussion regarding #4699, turn on
`misc-non-private-member-variables-in-classes` using the
`IgnoreClassesWithAllMemberVariablesBeingPublic` flag (the check treats
structs as classes, so we need this for structs with all-public
members). Updates the style guide notes to match, which should be pretty
minor due to the scoping of test fixtures.

Also fixes some underscore uses in test files on the way. Basically this
is keeping the style for [class data member
naming](https://google.github.io/styleguide/cppguide.html#Variable_Names)
even while making them public.
2024-12-19 00:31:41 +00:00
8e8d570571 Proposal: Variadics (#2240)
Proposes a set of core features for declaring and implementing generic
variadic
functions.

A "pack expansion" is a syntactic unit beginning with `...`, which is a
kind of
compile-time loop over sequences called "packs". Packs are initialized
and
referred to using "pack bindings", which are marked with the `each`
keyword at
the point of declaration and the point of use.

The syntax and behavior of a pack expansion depends on its context, and
in some
cases by a keyword following the `...`:

- In a tuple literal expression (such as a function call argument list),
`...`
iteratively evaluates its operand expression, and treats the values as
    successive elements of the tuple.
- `...and` and `...or` iteratively evaluate a boolean expression,
combining
the values using `and` and `or`, and ending the loop early if the
underlying
    operator short-circuits.
-   In a statement context, `...` iteratively executes a statement.
- In a tuple literal pattern (such as a function parameter list), `...`
iteratively matches the elements of the scrutinee tuple. In conjunction
with
    pack bindings, this enables functions to take an arbitrary number of
    arguments.

---------

Co-authored-by: josh11b <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
2024-12-11 01:58:40 +00:00
Dana JansensandJon Ross-Perkins dc5edb88fb Explain bazel is an alias to bazelisk, and recommend that for linux (#4603)
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-12-03 21:30:56 +00:00
Jon Ross-Perkins 0c2ed1b14e Switch from bazeliskrc to bazelversion (#4612)
The only documentation I can find for `.bazelversion` is in
https://github.com/bazelbuild/bazelisk/blob/master/README.md. However,
`bazel` will error out if it doesn't match the `.bazelversion`. For
example:

```
╚╡/usr/bin/bazel build :all
ERROR: The project you're trying to build requires Bazel 7.3.0 (specified in [elided]/carbon-lang/.bazelversion), but it wasn't found in /usr/bin.
```

Switching to this because the `MODULE.bazel` requires tighter version
pinning in order to avoid churn, and this should help catch mistakes
early.

In `MODULE.bazel`, demote mention of the version issue because it should
only really occur now when the version is being deliberately changed, so
the connection should be more apparent.
2024-12-03 17:52:20 +00:00
Jon Ross-Perkins d8ecc72d9d Update pre-commit config (#4549)
Skipping prettier because the relevant repo is archived and not working
well. Issues being fixed are from codespell.
2024-11-18 21:29:30 +00:00
Jon Ross-Perkins 6dce164c49 Change the bazel-out structure to avoid busybox symlinks. (#4505)
As described in symlink_helpers.bzl, copied here for visibility:

Symlinking busybox things needs special logic.

This is because Bazel doesn't cache the actual symlink, resulting in
essentially resolved symlinks being produced in place of the expected
tool. As a consequence, we can't rely on the symlink name when dealing
with busybox entries.

An example repro of this using a local build cache is:

    bazel build //toolchain
    bazel clean
    bazel build //toolchain

We could in theory get reasonable behavior with
`ctx.actions.declare_symlink`, but that's disallowed in our `.bazelrc`
for cross-environment compatibility.

The particular approach here uses the Python script as a launching pad
so that the busybox still receives an appropriate location in argv[0],
allowing it to find other files in the lib directory. Arguments are
inserted to get equivalent behavior as if symlink resolution had
occurred.

The underlying bug is noted at:
https://github.com/bazelbuild/bazel/issues/23620
2024-11-08 22:08:50 +00:00
Jon Ross-PerkinsandChandler Carruth 9af06cc988 Adjust some build troubleshooting notes (#4471)
Came up due to [libc++ install
issues](https://discord.com/channels/655572317891461132/655577725347561492/1302023663155023905)

We've discussed clang version verification, and adding that as long as
I'm in here. The more significant bit is the libc++ check, which if it's
not installed should fail like:

```
(tons of output)
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/llvm-16/lib/clang/16/include
 /usr/local/include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
/usr/local/google/home/jperkins/.cache/bazel/_bazel_jperkins/85deb7d9d96f7e0e80b42618a55969d7/external/_main~clang_toolchain_extension~bazel_cc_toolchain/_temp:6:2: error: "No libc++ install found!"
#error "No libc++ install found!"
 ^
1 error generated.
ERROR: Analysis of target '//toolchain:toolchain' failed; build aborted: Analysis failed
INFO: Elapsed time: 0.265s, Critical Path: 0.08s
INFO: 1 process: 1 internal.
ERROR: Build did NOT complete successfully
```

pre-commit runs bazel, and GitHub runners have an old clang by default
(caught by the new check), so I'm installing here for a consistent
version.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2024-11-04 16:03:09 +00:00
Céline Dedaj bb874f21f7 Update conduct team member list (#4394)
deleted @flysand7 from the conduct team member list after they left the
team
2024-10-10 20:02:05 +00:00
Chandler Carruth 33954d1f20 Improve -c dbg, enabling Split DWARF and other enhancements (#4382)
This should substantially reduce the total build size of `-c dbg`
builds, and especially improve cache hits during incremental
development. I'm seeing over 50% reduction total on Linux in just the
raw size of a complete debug build. Even on macOS where we can't use
split DWARF there are substantial reductions.

Note that LLDB and GDB want slightly different flags to have the best
experience with split debug information, and so the build and
documentation have been updated to enable LLDB's flags by default but
provide clear instructions for switching to GDB's flags, and they are
structured so that this can be done persistently for an individual
developer.
2024-10-09 03:58:47 +00:00
Jon Ross-PerkinsandChandler Carruth 434ee32515 Style notes on passing and storing object addresses (#4310)
[Context](https://discord.com/channels/655572317891461132/821113559755784242/1283516297686286377).
Some relevant Google C++ style is at [Inputs and
Outputs](https://google.github.io/styleguide/cppguide.html#Inputs_and_Outputs).
#4301 is an example application of the style.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2024-09-20 23:53:02 +00:00
Jon Ross-PerkinsandChandler Carruth 8b0154ce85 Getting commit access (#4246)
Establish a process for getting commit access. We will:

-   Grant access based on a developer's commit history.
- Someone with commit access should nominate, and a contributor may ask.
    -   A lead will approve nominations. Only one lead is needed.
-   Remove commit access once someone is idle for 6 months.
- "Idle" means no significant project activity on any of GitHub,
Discord,
        or in meetings.
    -   Access removed due to being idle will be restored on request.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2024-09-03 23:41:22 +00:00
Jon Ross-Perkins b9e9e66cee Update group documentation (#4250)
I'm trying to use this just to document the de facto state. This is
linked to #4246, but I'm trying to keep the two arranged to allow
independent merges.
2024-08-28 08:10:56 +00:00
Jon Ross-Perkins b73387fc84 Update workflows for security hardening. (#4192)
Also a small pass on workflow names.

Note, I'm a little concerned that the test/nightly release/pre-commit
endpoints may be fragile. At the same time, it's also where it may be
most useful, to prevent network access by arbitrary test code. I think
this is imperfect, but maybe we can try it out and see if it's much of
an issue.

Note, the discord wiki action is currently broken, this should fix it.
2024-08-06 23:14:23 +00:00
Brymer Meneses 70c20be91b docs: add a note on setting up clangd (#4135)
This PR adds a note on how to generate `compile_commands.json` which is
necessary for having `clangd` generate accurate diagnostics
2024-07-25 16:40:27 +00:00
Jon Ross-Perkins 407b9e4dcd Add a run_bazelisk wrapper script for linux. (#4129)
I was considering making a "/bazel" alias for this, but I'm really on
the fence about whether that's a good choice. However, I do think this
is good to have to simplify installs.

Fixes #3071 and #3896
2024-07-15 17:18:18 +00:00