gh-130956: emit AArch64 trampolines only for long jumps #131041
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Emit the AArch64 trampoline only if the address is more than 27 bits range. Enable the PLT for Linux AArch64: without it no trampolines are emitted at all and symbols are referenced via the GOT.
diegorusso
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diegorusso
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Mar 10, 2025
| @@ -507,6 +507,7 @@ def get_target(host: str) -> _COFF | _ELF | _MachO: | |||
| # On aarch64 Linux, intrinsics were being emitted and this flag | |||
| # was required to disable them. | |||
| "-mno-outline-atomics", | |||
| "-fplt", | |||
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This is needed otherwise trampolines are not generated at all and everything is referenced via the GOT. if you prefer, we can have this as separate PR.
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Yeah, this seems like this slows Linux down. Let's drop it.
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brandtbucher
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Yep, looks good!
Looks like it's ~0.4% slower on Linux, and ~0.8% faster on macOS (with 20-25% faster startup!). Maybe, given the results, we should roll back the new -fplt option for Linux? Otherwise, I think this makes sense to land.
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Emit the AArch64 trampoline only if the address is more than 27 bits range.
Enable the PLT for Linux AArch64: without it no trampolines are emitted at all and symbols are referenced via the GOT.