This commit is contained in:
bjorn3 2024-10-10 16:13:20 +00:00
commit 3cf701c845
8 changed files with 22 additions and 37 deletions

View file

@ -8,6 +8,7 @@ use rustc_ast::InlineAsmOptions;
use rustc_codegen_ssa::base::is_call_from_compiler_builtins_to_upstream_monomorphization;
use rustc_index::IndexVec;
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::mir::InlineAsmMacro;
use rustc_middle::ty::TypeVisitableExt;
use rustc_middle::ty::adjustment::PointerCoercion;
use rustc_middle::ty::layout::FnAbiOf;
@ -57,6 +58,7 @@ pub(crate) fn codegen_fn<'tcx>(
match &mir.basic_blocks[START_BLOCK].terminator().kind {
TerminatorKind::InlineAsm {
asm_macro: InlineAsmMacro::NakedAsm,
template,
operands,
options,
@ -498,6 +500,7 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
"tail calls are not yet supported in `rustc_codegen_cranelift` backend"
),
TerminatorKind::InlineAsm {
asm_macro: _,
template,
operands,
options,
@ -713,17 +716,17 @@ fn codegen_stmt<'tcx>(
let from_ty = operand.layout().ty;
let to_ty = fx.monomorphize(to_ty);
fn is_fat_ptr<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> bool {
fn is_wide_ptr<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> bool {
ty.builtin_deref(true)
.is_some_and(|pointee_ty| has_ptr_meta(fx.tcx, pointee_ty))
}
if is_fat_ptr(fx, from_ty) {
if is_fat_ptr(fx, to_ty) {
// fat-ptr -> fat-ptr
if is_wide_ptr(fx, from_ty) {
if is_wide_ptr(fx, to_ty) {
// wide-ptr -> wide-ptr
lval.write_cvalue(fx, operand.cast_pointer_to(dest_layout));
} else {
// fat-ptr -> thin-ptr
// wide-ptr -> thin-ptr
let (ptr, _extra) = operand.load_scalar_pair(fx);
lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
}

View file

@ -101,7 +101,7 @@ fn clif_pair_type_from_ty<'tcx>(
})
}
/// Is a pointer to this type a fat ptr?
/// Is a pointer to this type a wide ptr?
pub(crate) fn has_ptr_meta<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
if ty.is_sized(tcx, ParamEnv::reveal_all()) {
return false;

View file

@ -139,7 +139,7 @@ impl DebugContext {
pointer_type_id
} else {
// FIXME implement debuginfo for fat pointers
// FIXME implement debuginfo for wide pointers
self.placeholder_for_type(tcx, type_dbg, ptr_type)
}
}

View file

@ -2,6 +2,7 @@
//!
//! [`PointerCoercion::Unsize`]: `rustc_middle::ty::adjustment::PointerCoercion::Unsize`
use rustc_codegen_ssa::base::validate_trivial_unsize;
use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
use crate::base::codegen_panic_nounwind;
@ -34,20 +35,8 @@ pub(crate) fn unsized_info<'tcx>(
let old_info =
old_info.expect("unsized_info: missing old info for trait upcasting coercion");
if data_a.principal_def_id() == data_b.principal_def_id() {
// Codegen takes advantage of the additional assumption, where if the
// principal trait def id of what's being casted doesn't change,
// then we don't need to adjust the vtable at all. This
// corresponds to the fact that `dyn Tr<A>: Unsize<dyn Tr<B>>`
// requires that `A = B`; we don't allow *upcasting* objects
// between the same trait with different args. If we, for
// some reason, were to relax the `Unsize` trait, it could become
// unsound, so let's assert here that the trait refs are *equal*.
//
// We can use `assert_eq` because the binders should have been anonymized,
// and because higher-ranked equality now requires the binders are equal.
debug_assert_eq!(
data_a.principal(),
data_b.principal(),
debug_assert!(
validate_trivial_unsize(fx.tcx, data_a, data_b),
"NOP unsize vtable changed principal trait ref: {data_a} -> {data_b}"
);
return old_info;