usr.bin/clang: use -mxgot for MIPS
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Authored by kevans on Sep 18 2019, 2:19 AM.

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emaste
dim
arichardson

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rS353018: clang: use -mxgot for 32-bit mips

Summary

Various clang bits will fail to compile without -mxgot due to truncated relocations. -mxgot entails a speed penalty, but I do not think we care as much for the compiler in MIPS-land.

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rS FreeBSD src repository - subversion

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Buildable 26545

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kevans created this revision.Sep 18 2019, 2:19 AM

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Harbormaster completed remote builds in B26544: Diff 62247.Sep 18 2019, 2:19 AM

Re-upload... forgot to squash my first stab at it with the second stab that extended it to all MIPS32 and excluded 64-bit variants.

Harbormaster completed remote builds in B26545: Diff 62248.Sep 18 2019, 2:22 AM

I guess this happens because some files have more static globals than can be accessed in the immediate. In general lld should be able to use the multi-GOT trick but in that case it won't work.
If we really care about performance we could track down the individual files that need mxgot and only add it there but asking it globally should be fine.

Does it work for mips64 without mxgot? If it does I'm probably wrong and something else about the 32-bit ABI is stopping multi-GOT from being used.

This revision is now accepted and ready to land.Sep 18 2019, 7:55 AM

Yeah, mips64 is fine without -mxgot it seemed

Closed by commit rS353018: clang: use -mxgot for 32-bit mips (authored by kevans). · Explain WhyOct 2 2019, 5:15 PM

This revision was automatically updated to reflect the committed changes.

kevans added a commit: rS353018: clang: use -mxgot for 32-bit mips.

dim mentioned this in rS356460: Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp.Jan 7 2020, 6:13 PM

dim mentioned this in rS360658: Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp.May 5 2020, 1:05 PM