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Tweak type inference for const operands in inline asm

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Previously these would be treated like integer literals and default to
`i32` if a type could not be determined. To allow for
forward-compatibility with `str` constants in the future, this PR
changes type inference to use an unbound type variable instead.

The actual type checking is deferred until after typeck where we still
ensure that the final type for the `const` operand is an integer type.
This commit is contained in:
Amanieu d'Antras 2024-05-26 00:11:32 +01:00
parent eb10639928
commit 4d747128eb
2 changed files with 24 additions and 9 deletions
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24
compiler/rustc_hir_analysis/src/check/intrinsicck.rs
View File

@ -455,10 +455,26 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
);
}
}
// No special checking is needed for these:
// - Typeck has checked that Const operands are integers.
// - AST lowering guarantees that SymStatic points to a static.
hir::InlineAsmOperand::Const { .. } | hir::InlineAsmOperand::SymStatic { .. } => {}
hir::InlineAsmOperand::Const { anon_const } => {
let ty = self.tcx.type_of(anon_const.def_id).instantiate_identity();
match ty.kind() {
ty::Error(_) => {}
ty::Int(_) | ty::Uint(_) => {}
_ => {
self.tcx
.dcx()
.struct_span_err(*op_sp, "invalid type for `const` operand")
.with_span_label(
self.tcx.def_span(anon_const.def_id),
format!("is {} `{}`", ty.kind().article(), ty),
)
.with_help("`const` operands must be of an integer type")
.emit();
}
};
}
// AST lowering guarantees that SymStatic points to a static.
hir::InlineAsmOperand::SymStatic { .. } => {}
// Check that sym actually points to a function. Later passes
// depend on this.
hir::InlineAsmOperand::SymFn { anon_const } => {

9
compiler/rustc_hir_typeck/src/lib.rs
View File

@ -264,11 +264,10 @@ fn infer_type_if_missing<'tcx>(fcx: &FnCtxt<'_, 'tcx>, node: Node<'tcx>) -> Opti
Node::Expr(&hir::Expr { kind: hir::ExprKind::InlineAsm(asm), span, .. })
| Node::Item(&hir::Item { kind: hir::ItemKind::GlobalAsm(asm), span, .. }) => {
asm.operands.iter().find_map(|(op, _op_sp)| match op {
hir::InlineAsmOperand::Const { anon_const } if anon_const.hir_id == id => {
// Inline assembly constants must be integers.
Some(fcx.next_int_var())
}
hir::InlineAsmOperand::SymFn { anon_const } if anon_const.hir_id == id => {
hir::InlineAsmOperand::Const { anon_const }
| hir::InlineAsmOperand::SymFn { anon_const }
if anon_const.hir_id == id =>
{
Some(fcx.next_ty_var(span))
}
_ => None,