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codegen #[naked] functions using global_asm!

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Folkert 2024-08-08 10:20:40 +02:00 • committed by Folkert de Vries
parent 9c707a8b76
commit bd8f8e0631
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18 changed files with 624 additions and 102 deletions
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8
compiler/rustc_codegen_llvm/src/asm.rs
View file

@ -442,6 +442,14 @@ impl<'tcx> AsmCodegenMethods<'tcx> for CodegenCx<'_, 'tcx> {
);
}
}
fn mangled_name(&self, instance: Instance<'tcx>) -> String {
let llval = self.get_fn(instance);
llvm::build_string(|s| unsafe {
llvm::LLVMRustGetMangledName(llval, s);
})
.expect("symbol is not valid UTF-8")
}
}
pub(crate) fn inline_asm_call<'ll>(

14
compiler/rustc_codegen_llvm/src/attributes.rs
View file

@ -395,17 +395,9 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
to_add.push(MemoryEffects::None.create_attr(cx.llcx));
}
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
to_add.push(AttributeKind::Naked.create_attr(cx.llcx));
// HACK(jubilee): "indirect branch tracking" works by attaching prologues to functions.
// And it is a module-level attribute, so the alternative is pulling naked functions into
// new LLVM modules. Otherwise LLVM's "naked" functions come with endbr prefixes per
// https://github.com/rust-lang/rust/issues/98768
to_add.push(AttributeKind::NoCfCheck.create_attr(cx.llcx));
if llvm_util::get_version() < (19, 0, 0) {
// Prior to LLVM 19, branch-target-enforcement was disabled by setting the attribute to
// the string "false". Now it is disabled by absence of the attribute.
to_add.push(llvm::CreateAttrStringValue(cx.llcx, "branch-target-enforcement", "false"));
}
// do nothing; a naked function is converted into an extern function
// and a global assembly block. LLVM's support for naked functions is
// not used.
} else {
// Do not set sanitizer attributes for naked functions.
to_add.extend(sanitize_attrs(cx, codegen_fn_attrs.no_sanitize));