- Add pkg rules to the search, specifically so that we can pull the full
release tar instead of the busybox binary.
- Shift the tree_sitter exclusion to the script, so that it's easier to
use the script.
- tcmalloc_if_linux_opt isn't really interesting (it's referenced by
.bazelrc).
- Misc tiny changes to the query, just to simplify it.
Rules executed by bazel don't necessarily have the right environment to
find the symbolizer, which was the intent of `cc_env` setting
`LLVM_SYMBOLIZER_PATH`. So far, this has kind of been a case-by-case
fix, but every so often I'm trying to debug a crash in a test that
doesn't provide it. Rather continuing down this route, instead add
drop-in wrappers for cc rules so that it's hard to forget.
Note `bazel/cc_rules` is intended to mirror `bazel/carbon_rules` and
`bazel/cc_toolchains`, rather than `@rules_cc`.
AFAICT there isn't a great way to add this as a default for the `bazel
run` environment. It's not typically going to be set on its own,
forwarding `$PATH` would be too broad, and the [action
`env_sets`](https://bazel.build/docs/cc-toolchain-config-reference#using-action-config)
I think are not quite what we need (I think those don't include output
execution, only compilation).
I'm doing this separately from removing the explorer/ and installers/
directories so that it's easier to review the side-effects.
Note for the main README, I didn't think it was worth keeping a mention
of "used to have a prototype interpreter, now archived" versus focusing
on the existing toolchain (for "Currently, we have fleshed out").
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Inconsistent execution environments make using a path-as-define
difficult, so switch to an embedded file.
Also fixes the lldb launch so that passing tests run cleanly, and adds
TEST_TARGET to gdb (but without testing there). I'm dropping `sourceMap`
because it's not handled quite correctly (also not great to be trying to
pass source mappings in two different ways), and `env` didn't seem to be
working as intended either; maybe specifying `initCommands` causes other
things to not be evaluated. But the straight `initCommands` looks like
it's working. I used lldb to validate execution of these changes.
```
Running initCommands:
(lldb) command script import external/+llvm_project+llvm-project/llvm/utils/lldbDataFormatters.py
(lldb) settings set target.source-map "." "/usr/local/google/home/jperkins/dev/carbon-lang"
(lldb) settings set target.source-map "/proc/self/cwd" "/usr/local/google/home/jperkins/dev/carbon-lang"
(lldb) env TEST_TARGET=//toolchain/testing:file_test
(lldb) env TEST_TMPDIR=/tmp
Running tests with 128 thread(s)
.
Done!
Note: Google Test filter = ToolchainFileTest.toolchain/check/testdata/const/collapse.carbon
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from ToolchainFileTest
[ RUN ] ToolchainFileTest.toolchain/check/testdata/const/collapse.carbon
[ OK ] ToolchainFileTest.toolchain/check/testdata/const/collapse.carbon (0 ms)
[----------] 1 test from ToolchainFileTest (0 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (1 ms total)
[ PASSED ] 1 test.
Process 3869310 exited with status = 0 (0x00000000)
```
- The actual reason I started this: minor lowering updates in the golden
LLVM IR
- Process.inc changed enough to need a patch context update.
- https://github.com/llvm/llvm-project/pull/123126 added `proto_library`
uses without a `load`, which is broken in bazel 8
- Just commenting these out because we don't use them. I'll follow up
separately about a possible fix, but continuing to use `WORKSPACE` is a
bigger issue LLVM probably should address.
- Note this update is also triggering removal of `migrate_cpp`, in #4887
Although migration tooling is intended for Carbon, this tooling was
primarily a proof-of-concept prototype. The last time it got significant
work was in 2022
(https://github.com/carbon-language/carbon-lang/commits/trunk/migrate_cpp);
since then, we've mainly been doing small cleanups to keep it building.
We're now hitting an issue in #4886 that `TypeNodes.inc` isn't exposed
as a `#include`.
We already had thoughts about rewriting this as a `RecursiveASTVisitor`,
per `rewriter.cpp`/`rewriter.h`. That may justify a significantly
different approach than had been set up in `cpp_refactoring`. But, it's
hard to tell.
Either way, my sense is that rather than incrementally trying to keep
this code building, we should revisit it when we're ready and have a
long-term strategy for how migration should work.
The WORKSPACE file is deprecated; support is already off by default, and
it'll be removed in the next major bazel release. Our main dependency is
tree-sitter, and I'm trying to address that here.
We're currently using https://github.com/elliottt/rules_tree_sitter, but
that hasn't been updated in a couple years, meaning it lacks
MODULE.bazel support. In the registry, there's
https://registry.bazel.build/modules/tree-sitter-bazel, but this is only
the *parser* libraries of tree-sitter, not the *generator*. I'm using it
for that much, at least.
For the *generator*, which transforms grammar.js to parser.c/h, I'm just
requiring a non-hermetic invocation (i.e., people who want to work on it
will need to install tree-sitter; see the README.md updates). I tried
running it manually, but parser.c is about 600 KB; pre-commit rejects
files that large and I don't think an exception makes sense to override
for this (it'd probably also grow substantially if the grammar were
updated to cover more syntax). In order to make the non-hermetic call
not break "bazel build //..." for most developers, I'm marking most
targets in the package as manual.
Note, I did look long and hard at using `aspect_rules_js`/`rules_nodejs`
to invoke npm. This took a lot of time, and I have a commit that's
mostly working, except I hit a point where it uses `declare_symlink`
which we disallow for compatibility reasons (commit "Lots of work for
figuring out rule_js uses declare_symlink" on the PR). As a consequence,
I think we can't use the primary supported ways to have hermetic npm
calls.
Also, `treesitter` -> `tree_sitter` because it's generally called
`tree-sitter`, two words. We even had a `treesitter/src/tree_sitter`
directory so it's a bit inconsistent.
As far as bugs here, the parser library breaks bazel queries, e.g. the
error:
```
ERROR: Evaluation of query "somepath(//..., @llvm-project//third-party/unittest:gtest)" failed: preloading transitive closure failed: no such package '@@[unknown repo 'platforms' requested from @@tree-sitter-bazel+]//': The repository '@@[unknown repo 'platforms' requested from @@tree-sitter-bazel+]' could not be resolved: No repository visible as '@platforms' from repository '@@tree-sitter-bazel+'
```
I'm just excluding tree_sitter from queries where I can to work around
the error.
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.
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.
As part of migrating to the latest bazel configurations in #4729, I'm
running into proto toolchain issues. For example:
"Error: <target @@protobuf+//:cc_toolchain> (rule
'proto_lang_toolchain') doesn't contain declared provider
'ProtoLangToolchainInfo'"
Although we may eventually want more use of proto, right now the only
use is for the explorer fuzzer. The explorer codebase is essentially
frozen, so continuing to run it isn't gaining us much (in fact, we've
already disabled autofuzzing for it).
So, rather than trying to fix the proto setup, this change:
1. Deletes `explorer/fuzzing`
2. Removes proto portions of `testing/fuzzing`, which were only in-use
by the explorer
3. Removes some ancillary proto support, which would otherwise break
from the bazel changes and would be difficult to validate as "still
working"
This change is partly isolated in order to make it easier to revive bits
of (3).
Instead of treating `Core.Int` as the toolchain's builtin `IntType`,
model it as a class that adapts the builtin type. This aligns us better
with the intended language model, gives an associated library for
`impl`s involving `Core.Int` to live within, and opens the door adding
member functions to `Core.Int` if we decide that is desirable.
Remarkably it also seems to make the formatted SemIR a little smaller,
because a call to a generic class generates less IR than a call to a
function.
Also make `-gsimple-template-names` lldb-only due to it tripping up gdb
in some cases (I came across it breaking SmallVector pretty printing
where gdb wouldn't associate a simplified type named declaration with a
simplified type named definition in another translation unit - seems gdb
can associate a type decl/def when it sees both (if you step into both
translation units or otherwise trigger gdb loading/parsing them) but it
doesn't seem able to /search/ for the type definition). Filed
https://sourceware.org/bugzilla/show_bug.cgi?id=32421 for this.
A couple of other things I'd like to do, but don't know how:
* It might be nice to allow opting into or out of gdb_index (with the
default being 'on' for gdb_flags, but you could opt out). But doesn't
seem super important.
* We should turn off fission by default, it seems - bazel has trouble
making the .dwo files available at the same path as is in the binary
especially on partial rebuilds. (not sure if we can do that, I guess
we can make fission a no-op/doesn't add any flags, even if we can't
change the fission default in bazel itself)
* can we have gdb_flags imply/disable lldb_flags? (so you can use
--features=gdb_flags without always having to add
--features=-lldb_flags)
In llvm 17 the _LIBCPP_ENABLE_ASSERTIONS flag was split into two:
- _LIBCPP_ENABLE_HARDENED_MODE for fast checks
- _LIBCPP_ENABLE_DEBUG_MODE for expensive checks
We kept HARDENED_MODE enabled in debug, but we can also turn it on for
opt builds.
In llvm 18, the _LIBCPP_ENABLE_HARDENED_MODE was further split into 4
settings, NONE, FAST, EXTENSIVE, DEBUG. As seen in the recent blog post
https://security.googleblog.com/2024/11/retrofitting-spatial-safety-to-hundreds.html
the FAST hardening mode is indeed very fast and has minimal impact,
while helping to catch a lot of bugs.
So we enable the FAST checks in opt builds, and EXTENSIVE checks in
debug builds.
The EXTENSIVE checks are the same that Chrome enables in every build
configuration, so we could consider enabling it in opt builds as well:
https://source.chromium.org/chromium/chromium/src/+/main:build/config/compiler/BUILD.gn;l=1127;drc=a8260dee097dde71ca4464c0c8d897a80c353db2
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>
Removes the separate language server binary; I'm not sure we need to
provide it. Instead, `carbon language-server` is added as a subcommand.
Moves //language_server to //toolchain/language_server. Splits into a
trivial language_server.h, and a substantive server.h. I wasn't sure
about a better name, but wanted the split similar to check/check.h,
lex/lex.h, etc. At the same time, the class is probably going to be a
little big so not a good fit to through into just a cpp file.
This fixes some style issues with the language server class, but
generally I'm trying to not address things here in order to keep it
simpler.
For reference, we're going down the busyboxing route because Carbon
depends on Clang, and we want both to be available as binaries.
Busyboxing allows this while avoiding duplicating symbols between
multiple binaries.
I'm removing the `cc_binary` for `driver:carbon` because I want to avoid
a significant increase in binary outputs; `bazel run //toolchain` still
works great.
This still doesn't have great test coverage (but non-zero:
`//examples:sieve` still builds/runs, for example). The problem is that
we want to avoid subprocessing for performance, but this mainly deals
with subprocessing. I'm still thinking about good approaches for that,
since we'll probably want more significant testing for `clang`
interaction... the solution might involve busyboxing `file_test` too.
Note development on this ran into the argv issue being fixed in #4405
I was looking at the documentation again, and I realized that while this
works, I think the intention is that `runfiles` is set _instead_ of both
fields (I was a little confused by the error I was getting when setting
`runfiles` _with_ `default_runfiles`)
I believe I've verified this works in necessary situations.
Use the diagnostic kind printing in #4425 to catch when we have
diagnostics with no tests.
This merges a couple other use-cases of filegroup manifests into a
common rule.
Note I do add a few tests for things, and also some things are
_actually_ unit tested (just not in the file_test structure). But I
stopped when I realized that dealing with merge conflicts is going to be
a pain. I might end up reverting test changes (as part of merge conflict
resolution) and doing narrow test additions in a separate PR, after both
this and #4425 are merged.
Undoes most of #4347, because of [performance
complaints](https://discord.com/channels/655572317891461132/707150492370862090/1295527235133898772).
With a 30-ish frame stack trace and `-c dbg`, my installed
`llvm-symbolizer` still seems slow (~6s), but the hermetic
`llvm-symbolizer` adds ~4s (i.e., ~10s total). I don't think we can
easily force the hermetic version to build in opt configuration, so I'm
backing it out.
@bazel_tools//tools/cpp:malloc is equivalent and comes from
https://bazel.build/reference/be/c-cpp#cc_binary.malloc. This also
avoids some confusion in the documentation, since while system_malloc
_can_ be used with `malloc`, it has no effect when it's used with
`--custom_malloc`. But, rather than trying to adjust that, maybe we can
just use @bazel_tools//tools/cpp:malloc
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.
Causes the default development (`fastbuild`) Bazel build and test to
both use ASan, minimal optimizations, and produce good backtraces with
source locations.
This also fixes all of the non-host configs that were deeply broken for
the latest releases of Bazel going back quite some time.
The intent of our our Bazel toolchain config was for a minimally
optimized, minimal debug info, and ASan + UBSan configuration to be the
`fastbuild`, or the default development build of the project. This
matches its inclusion of asserts, etc.
At some point quite some time ago, all of this stopped working. Bazel no
longer has a `nonhost` feature. This was disabled a long time ago,
briefly argued to be re-enabled, but has persistently been removed.
However, since then the host and non-host features have been separated
including the compilation mode, and so none of that is needed now.
Instead, we can use a much simpler and more principled approach to all
of the feature configuration now which this PR implements.
However, we added TCMalloc _after_ all of the ASan stuff became broken,
and so we never saw that it is fundamentally incompatible with ASan. So
this PR also reworks how TCMalloc is used to only apply to `-c opt`
builds on Linux, and it also explicitly disables it when using
`--config=asan`. I've not found a convenient way to tie the malloc
library choice to a toolchain feature in Bazel, so this relies on the
config being used rather than the feature in isolation.
Last but not least, with this change `fastbuild` creates substantially
larger output and so this change also passes several new flags to reduce
the size costs. One is a general improvement from outlining ASan
instrumentation. The others are in a special feature as they reduce the
error message quality for two of the more expensive UBSan checks in
favor of small generated code size. Keeping these last two separate
allows disabling this locally if needed to debug a failure.
This only sets the symbolizer for our more used targets; not sure if
there's a great way to set it everywhere (I suppose I could try wrapping
cc_binary etc rules if there's a strong preference).
There is a downside here, symbolizing a fastbuild crash seems to take
about 3s. Not sure if there's a good way to get a faster llvm-symbolizer
execution...?
I tried running with the new LLVM update without the
LLVM_SYMBOLIZER_PATH, and it looks like that's insufficient. With the
settings, I now get readable crashes:
```
#9 0x000055dc007d1724 void Carbon::Internal::CheckFail<Carbon::TemplateString<5>{"FATAL"}, Carbon::TemplateString<27>{"toolchain/driver/driver.cpp"}, 84, Carbon::TemplateString<0>{}, Carbon::TemplateString<3>{"err"}>() (/usr/local/google/home/jperkins/.cache/bazel/_bazel_jperkins/85deb7d9d96f7e0e80b42618a55969d7/sandbox/linux-sandbox/9383/execroot/_main/bazel-out/k8-fastbuild/bin/toolchain/testing/file_test.runfiles/_main/toolchain/testing/file_test+0x2894724)
```
Note the LLVM update is for
https://github.com/llvm/llvm-project/pull/109021
I think `paths.parents[2]` is easier to read than
`path.parent.parent.parent`, just applying uniformly. I'd noticed this
while looking at #4227
Also remove a couple `resolve()` calls that shouldn't be necessary since
`__file__` is absolute (elsewhere in the same files, `resolve()` is used
to resolve potentially relative paths)
This improve the toolchain's performance by about 10%.
It will also allow us to leverage TCMalloc's extensions to do heap
profiling and get other information about how efficiently we're using
the heap.
Note that currently this causes all of our builds to produce a warning
due to an issue with `rules_python` and multiple modules registering
python toolchains:
https://github.com/bazelbuild/rules_python/issues/1818
This is also only enabled on Linux as there is no support for other OSes
at the moment.
Most of this is enabled by default, but there is some that needs an
explicit flag.
Avoiding `-Wnon-virtual-dtor` itself for now because that warning can
require changes that carry overhead such as having an extra, unused
destructor entry in the vtable. Hopefully we don't have too many folks
who need our code to be `-Wnon-virtual-dtor` clean.
This switches from a macro that simply wraps genrules to a proper
Starlark rule that runs first compile and then link actions.
Most interestingly, this uses the rule structure to allow using the
Carbon toolchain built either in the target config or the exec config.
While the exec config is more principled and even necessary in a
cross-compile situaiton, it is dramatically less efficient when
developing Carbon as all the binaries and tests outside of our examples
will be built with the target config. This triggers a complete second
build of the toolchain in the exec config for examples before this PR.
It is tempting to try to keep the exec config but make it not cause
redundant actions, but the way Bazel sets up exec and target config
makes it essentially impossible to share their artifacts. There used to
be a hack in Bazel itself to force sharing but it was removed due to it
violating the principled design. Instead, these rules are explicit about
their intent to use the target config, much like a test would be.
I have rigged up a flag that is carefully threaded through a wrapper
macro with `select`s to allow easily switching to the exec configuration
in case it is desired or needed. But the the `.bazelrc` sets the default
to the target config. The `BUILD` file default is the principled `exec`
in case these rules are used by importing into some other Bazel
workspace where we might *only* need the exec config.
The net outcome of this is shaving over 2500 actions off of a clean
rebuild such as is triggered by a version bump to LLVM, including some
of the very slow and expensive compiles of LLVM and Clang themselves.
These would only be triggered if you built the examples so this may
mostly impact our CI latency.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Updating to 1.8.4 breaks the patch file, so I'm looking at solutions
that don't require maintaining a patch.
Verifying this is working with `bazel build
//toolchain/lex:tokenized_buffer_benchmark && strings
bazel-bin/toolchain/lex/tokenized_buffer_benchmark |& grep pfm`
I inadvertently didn't commit and push the actual fixes suggested and
made to that PR, and didn't notice this before putting it into the merge
queue. =[ Very sorry, these were supposed to be in that PR.
This adds a defined Carbon version to the Bazel build and codebase that
can be used both to implement features like version checks and to report
a meaningful version on the command line. This replaces a hard-coded
string and a TODO in the driver.
As part of this, it adds support for defining the version in Bazel, and
special build flags for overriding relevant parts such as the
pre-release marker used. The exact structure and meaning of our version
string, including the pre-release parts, is implemented here in line
with the draft proposal:
https://docs.google.com/document/d/11S5VAPe5Pm_BZPlajWrqDDVr9qc7-7tS2VshqO0wWkk/edit?resourcekey=0-2YFC9Uvl4puuDnWlr2MmYw
This also introduces a workspace status command to the repository to
extract the git commit SHA and other information when building, and the
logic to stamp that into binaries as part of the version string when
useful. The technique used leverages weak symbols with whole archive
linking to allow a link-time override of unstamped data with stamped
data in the leaf executable. This makes building with `--stamp` a
reasonable default, especially for development builds. The CI system is
explicitly opted out of this as there it has no benefit.
Last but not least, all of these are wired into the install rules so
that we build installable packages with the version number in a
conventional place in the directory and filename.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This uses a header-only extraction of the Boost unordered hashtable
project to allow a trivial Bazel build and for us to benchmark against
it effectively.
Most of these are places where we failed to include a header file and
simply never got an error about this. The fix is to include the header
file.
Most other cases are functions that should have been marked `static` but
were not. Finding all of these was a main motivation for me enabling the
warning despite how much work it is.
One complicating factor was that we weren't including the `handle.h` for
all the state-based handler functions. While this isn't a tiny amount of
code, it is just declarations and doesn't add any extra dependencies. It
also lets us have the checking for which functions need to be `static`
and which don't. For the `parse` library I had to add the `handle.h`
header as well, I tried to match the design of it in `check`.
I have also had to work around a bug in the warning, but given the value
it seems to be providing, that seems reasonable. I've filed the bug
upstream: https://github.com/llvm/llvm-project/issues/94138
I also had to use some hacks to work around limitations of Bazel rules
that wrap `cc_library` rules and don't expose `copts`. I filed a bug for
`cc_proto_library` specifically:
~https://github.com/bazelbuild/bazel/issues/22610~https://github.com/bazelbuild/bazel/issues/4446
Just spotted these while looking at warnings that seem to fire on our
code are probably are things we'd fix if we saw them. None of these seem
important FWIW.
Also removes a redundant flag that is part of `-Wall`.
I have a follow-up for the high-value warning I spotted that motivated
me to look at all of this. But it's noisy so kept it as a separate PR.
I misunderstood how this flag worked, which explains why it didn't work.
Oops. Sorry about that. So far we've been lucky to not bump into this,
but we've had to work around it with updating libraries, etc.
Moreover, there are quite a few warnings that seem useful for us to
enable, but doing so would cause lots of friction without this working.
The added warnings will be separate PRs along with their cleanups.
This removes the `data_dir` from the driver favoring the installation
abstraction for the both locating the prelude and linking utilities.
With this, an installed toolchain should also be able to compile and
link Carbon successfully, and the build of the examples should exercise
this path almost exactly. (The only difference is using the driver
`cc_binary` directly rather than relying on the symlink from inside the
install tree.)
The install directory contains the BUILD logic for creating an
installable tree of data files and executables for the toolchain, and
a library to facilitate toolchain code accessing the paths to their data
within this installation.
Then adds an installation of LLD in a synthetic LLVM installation, and
teaches the Clang runner to configure this and use it for linking
instead of the system linker.
Currently, the install paths only really manage access to the LLVM
binaries installed and used by the Clang runner for linking, but
eventually other data files like the prelude and runtime libraries will
be fleshed out as well. There are TODOs for moving more things over here
such as the prelude.
One interesting aspect of this is where to put helpers like parts of
LLVM in our install. This PR suggests nesting those files under
`lib/carbon`. While using a `lib` subdirectory isn't a perfect fit for
the FHS (Filesystem Hierarchy Standard), having a single location where
private data is collected is significantly superior to spreading them
across the system. This also matches similar patterns used by Clang
itself and several other language toolchains and standard libraries.
The install directory also provides a natural place for us to build out
packaging rules to create installable packages in various formats, but
that remains future work.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
The driver now looks for all files under core/prelude/ and considers
them all to be part of the prelude. The driver also now only processes
the prelude in `--phase=check` and later, when it would actually be
imported.
With that done, add a simple `carbon_binary` build rule and use it to
build the example in `//examples`. This should cause the example to be
built as part of our continuous integration.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Jon Ross-Perkins
David Blaikie
Dana Jansens
