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Auto merge of #122671 - Mark-Simulacrum:const-panic-msg, r=Nilstrieb

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Codegen const panic messages as function calls

This skips emitting extra arguments at every callsite (of which there
can be many). For a librustc_driver build with overflow checks enabled,
this cuts 0.7MB from the resulting shared library (see [perf]).

A sample improvement from nightly:

```
        leaq    str.0(%rip), %rdi
        leaq    .Lalloc_d6aeb8e2aa19de39a7f0e861c998af13(%rip), %rdx
        movl    $25, %esi
        callq   *_ZN4core9panicking5panic17h17cabb89c5bcc999E@GOTPCREL(%rip)
```

to this PR:

```
        leaq    .Lalloc_d6aeb8e2aa19de39a7f0e861c998af13(%rip), %rdi
        callq   *_RNvNtNtCsduqIKoij8JB_4core9panicking11panic_const23panic_const_div_by_zero@GOTPCREL(%rip)
```

[perf]: https://perf.rust-lang.org/compare.html?start=a7e4de13c1785819f4d61da41f6704ed69d5f203&end=64fbb4f0b2d621ff46d559d1e9f5ad89a8d7789b&stat=instructions:u
This commit is contained in:
bors 2024-03-29 00:24:01 +00:00
commit db2f9759f4
12 changed files with 253 additions and 61 deletions
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21
compiler/rustc_monomorphize/src/collector.rs
View file

@ -971,16 +971,17 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
}
}
}
mir::TerminatorKind::Assert { ref msg, .. } => {
let lang_item = match &**msg {
mir::AssertKind::BoundsCheck { .. } => LangItem::PanicBoundsCheck,
mir::AssertKind::MisalignedPointerDereference { .. } => {
LangItem::PanicMisalignedPointerDereference
}
_ => LangItem::Panic,
};
push_mono_lang_item(self, lang_item);
}
mir::TerminatorKind::Assert { ref msg, .. } => match &**msg {
mir::AssertKind::BoundsCheck { .. } => {
push_mono_lang_item(self, LangItem::PanicBoundsCheck);
}
mir::AssertKind::MisalignedPointerDereference { .. } => {
push_mono_lang_item(self, LangItem::PanicMisalignedPointerDereference);
}
_ => {
push_mono_lang_item(self, msg.panic_function());
}
},
mir::TerminatorKind::UnwindTerminate(reason) => {
push_mono_lang_item(self, reason.lang_item());
}