This patches bazel_clang_tidy handling of headers. I found an equivalent
change at https://github.com/erenon/bazel_clang_tidy/pull/13, but that
was [already
rejected](https://github.com/erenon/bazel_clang_tidy/pull/13#issuecomment-1047007424).
Per the criticism, this will result in redundant processing of headers.
The project instead uses `HeaderFilterRegex: ".*"`, but that results in
two problems:
1. When running with `-k`, errors are repeated when a header is included
more than once, which is common.
2. clang-tidy including errors from headers that are included from other
modules (e.g., abseil-cpp); filtering correctly is difficult.
Given the trade-offs and options (including forking), I thought patching
was preferable so long as it remains narrow.
This sets things up to use `bazel` to run `clang-tidy` using
https://github.com/erenon/bazel_clang_tidy.
I'm fixing issues outside of explorer, and disabling clang-tidy for
targets in explorer that have legacy issues. I was going to disable
clang-tidy for targets in explorer such as interpreter anyways, because
they're slow to parse, and just extended that to the currently failing
targets.
Per their documentation, the `llvm::Initialize*` functions are only
supposed to be called by the main program, not by a library like
toolchain/codegen. Fixes a hang due to a data race in multithreaded
autoupdate.
Add a utility class `Carbon::InitLLVM` to do the common LLVM
initialization shared by all Carbon tools, optionally including
initializing the LLVM targets. Because the LLVM targets add a lot of
binary size, only initialize them for binaries that opt in by depending
on a new target `//common:all_llvm_targets`.
Also fix `//explorer:file_test` and `//explorer:file_test.trace` to
share a binary rather than linking an identical binary twice.
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Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Jon Ross-Perkins
Richard SmithandJon Ross-Perkins