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Update for review

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This commit is contained in:
matt rice 2024-06-14 07:53:37 -07:00
parent a85700a1a8
commit 1de046fa24
1 changed files with 17 additions and 2 deletions
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19
compiler/rustc_hir_analysis/src/check/mod.rs
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@ -160,20 +160,35 @@ fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: LocalDefId) {
}
// For the wasm32 target statics with `#[link_section]` other than `.init_array`
// are placed into custom sections of the final output file, but this isn't link
// are placed into custom sections of the final output file, but this isn't like
// custom sections of other executable formats. Namely we can only embed a list
// of bytes, nothing with provenance (pointers to anything else). If any
// provenance show up, reject it here.
// `#[link_section]` may contain arbitrary, or even undefined bytes, but it is
// the consumer's responsibility to ensure all bytes that have been read
// have defined values.
//
// The `.init_array` section is left to go through the normal custom section code path.
// When dealing with `.init_array` wasm-ld currently has several limitations. This manifests
// in workarounds in user-code.
//
// * The linker fails to merge multiple items in a crate into the .init_array section.
// To work around this, a single array can be used placing multiple items in the array.
// #[link_section = ".init_array"]
// static FOO: [unsafe extern "C" fn(); 2] = [ctor, ctor];
// * Even symbols marked used get gc'd from dependant crates unless at least one symbol
// in the crate is marked with an `#[export_name]`
//
// Once `.init_array` support in wasm-ld is complete, the user code workarounds should
// continue to work, but would no longer be necessary.
if let Ok(alloc) = tcx.eval_static_initializer(id.to_def_id())
&& alloc.inner().provenance().ptrs().len() != 0
{
if attrs
.link_section
.map(|link_section| !link_section.as_str().starts_with(".init_array"))
.unwrap_or(true)
.unwrap()
{
let msg = "statics with a custom `#[link_section]` must be a \
simple list of bytes on the wasm target with no \