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Auto merge of #136410 - saethlin:clean-up-cgu-internal-copy, r=compiler-errors

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Remove InstanceKind::generates_cgu_internal_copy

This PR should not contain any behavior changes. Before this PR, the logic for selecting instantiation mode is spread across all of
* `instantiation_mode`
* `cross_crate_inlinable`
* `generates_cgu_internal_copy`
* `requires_inline`

The last two of those functions are not well-designed. The function that actually decides if we generate a CGU-internal copy is `instantiation_mode`, _not_ `generates_cgu_internal_copy`. The function `requires_inline` documents that it is about the LLVM `inline` attribute and that it is a hint. The LLVM attribute is called `inlinehint`, this function is also used by other codegen backends, and since it is part of instantiation mode selection it is *not* a hint.

The goal of this PR is to start cleaning up the logic into a sequence of checks that have a more logical flow and are easier to customize in the future (to do things like improve incrementality or improve optimizations without causing obscure linker errors because you forgot to update another part of the compiler).
This commit is contained in:
bors 2025-03-25 06:36:41 +00:00
commit 7d49ae9731
3 changed files with 68 additions and 64 deletions
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13
compiler/rustc_codegen_ssa/src/back/symbol_export.rs
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@ -95,16 +95,11 @@ fn reachable_non_generics_provider(tcx: TyCtxt<'_>, _: LocalCrate) -> DefIdMap<S
return None;
}
// Functions marked with #[inline] are codegened with "internal"
// linkage and are not exported unless marked with an extern
// indicator
if !Instance::mono(tcx, def_id.to_def_id()).def.generates_cgu_internal_copy(tcx)
|| tcx.codegen_fn_attrs(def_id.to_def_id()).contains_extern_indicator()
{
Some(def_id)
} else {
None
if Instance::mono(tcx, def_id.into()).def.requires_inline(tcx) {
return None;
}
if tcx.cross_crate_inlinable(def_id) { None } else { Some(def_id) }
})
.map(|def_id| {
// We won't link right if this symbol is stripped during LTO.