Add support for mingw-gcc. #171
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| # Other windows toolchains have these by default | ||
| build:mingw_gcc --cxxopt=-DHAVE_UNISTD_H=1 --host_cxxopt=-DHAVE_UNISTD_H=1 |
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I could run builds (at least partially) using clang-cl and msvc without those on config.bzl - it seems they're picked by default?
Since only mingw needed them, I put them here instead. Wdyt? Or do you mean setting a bazel constraint set for when mingw is used?
(my compiler-foo-ness is subpar so bear with me if I'm missing something obvious :))
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Or do you mean setting a bazel constraint set for when mingw is used?
I meant this. This is ok though.
What we should really do is detect the machine capabilities and encode it that way. The current method is really just a shortcut because Bazel is not well-equipped for that.
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I tried doing what you asked, but bazel is really challenging. Trying to set select conditions on anything that's not @bazel_tools//src/conditions:os (eg @bazel_tools//tools/cpp:mingw, //:my_platform, //:my_constraint) yielded either a "Your target can't be found" or "Your BUILD file can't be found" or "invalid constraint key" :/
llvm-bazel/.bazelrc
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| build:mingw_gcc --linkopt=-lole32 --host_linkopt=-lole32 | ||
| build:mingw_gcc --linkopt=-luuid --host_linkopt=-luuid | ||
| build:mingw_gcc --linkopt=-lversion --host_linkopt=-lversion |
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I'm guessing these are deps of particular libraries? It would be nice to not have to add them globally
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I moved them into the specific libraries. I also tried compiling them with msvc, which would complain about LNK4044... I tried adding (host_)linkopt=/IGNORE:4044 but no luck, the warnings are still there.
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So as currently configured (with them on the specific targets), this adds LNK4044 warnings to MSVC? That's worse than having them in the bazelrc, I think. I can take a look next week about trying to detect mingw properly, but otherwise let's just leave things in the bazelrc as you had previously. @chandlerc thoughts?
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When trying to run with
bazelisk build --config=msvc --compiler=msvc @llvm-project//llvm:llvm-tblgen
...
LINK : warning LNK4044: unrecognized option '/lole32'; ignored
LINK : warning LNK4044: unrecognized option '/luuid'; ignored
...
I think these are safe, albeit annoyingly verbose?
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Yeah warning spam is IMO indirectly unsafe though because it makes people ignore other warnings. I think it's not fair to degrade the MSVC build experience to add support for mingw_gcc
Note that this is also blocked by #130. That error also affects @llvm-project/llvm:llvm-mca-headers. This doesn't build _everything_. Particularly, the last error I got through was on setenv not being declared in llvm/llvm/unittests/Support/ThreadPool.cpp. I imagine the issue might be related to some of the other headers that we're including for linux and posix only.
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Note that this is also blocked by #130.
That error also affects @llvm-project/llvm:llvm-mca-headers.
This doesn't build everything. Particularly, the last
error I got through was on setenv not being declared in
llvm/llvm/unittests/Support/ThreadPool.cpp. I imagine the issue might be
related to some of the other headers that we're including for linux and
posix only.
Note that I can't get mingw-gcc to work with RBE. GCC on windows
will try to canonize paths that look shorter than the original ones:
https://github.com/gcc-mirror/gcc/blob/16e2427f50c208dfe07d07f18009969502c25dc8/libcpp/files.c#L405.
That means that relative includes (eg "lib/Support/../../", eg [1]) are made
absolute, which end up showing an absolute path on the
.dfiles.[1] https://github.com/llvm/llvm-project/blob/main/llvm/lib/Support/AArch64TargetParser.cpp#L58