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debuginfo: Support fat pointers to unsized tuples. #94050

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Merged
bors merged 1 commit into from
Feb 19, 2022
+27 −9
Merged

debuginfo: Support fat pointers to unsized tuples. #94050

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13 changes: 4 additions & 9 deletions compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ use super::CrateDebugContext;
use rustc_hir::def_id::DefId;
use rustc_middle::ty::layout::LayoutOf;
use rustc_middle::ty::{self, DefIdTree, Ty};
use rustc_target::abi::VariantIdx;
use rustc_target::abi::Variants;

use crate::common::CodegenCx;
use crate::llvm;
Expand Down Expand Up @@ -72,20 +72,15 @@ pub(crate) fn fat_pointer_kind<'ll, 'tcx>(
match *pointee_ty.kind() {
ty::Str | ty::Slice(_) => Some(FatPtrKind::Slice),
ty::Dynamic(..) => Some(FatPtrKind::Dyn),
ty::Adt(adt_def, _) => {
assert!(adt_def.is_struct());
assert!(adt_def.variants.len() == 1);
let variant = &adt_def.variants[VariantIdx::from_usize(0)];
assert!(!variant.fields.is_empty());
let last_field_index = variant.fields.len() - 1;

ty::Adt(..) | ty::Tuple(..) if matches!(layout.variants, Variants::Single { .. }) => {
let last_field_index = layout.fields.count() - 1;
debug_assert!(
(0..last_field_index)
.all(|field_index| { !layout.field(cx, field_index).is_unsized() })
);

let unsized_field = layout.field(cx, last_field_index);
assert!(unsized_field.is_unsized());
debug_assert!(unsized_field.is_unsized());
fat_pointer_kind(cx, unsized_field.ty)
}
ty::Foreign(_) => {
Expand Down
23 changes: 23 additions & 0 deletions src/test/debuginfo/unsized.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,14 @@
// gdbg-check:$3 = {pointer = [...], vtable = [...]}
// gdbr-check:$3 = &unsized::Foo<dyn core::fmt::Debug> {pointer: [...], vtable: [...]}

// gdb-command:print tuple_slice
// gdbg-check:$4 = {data_ptr = [...], length = 2}
// gdbr-check:$4 = &(i32, i32, [i32]) {data_ptr: [...], length: 2}

// gdb-command:print tuple_dyn
// gdbg-check:$5 = {pointer = [...], vtable = [...]}
// gdbr-check:$5 = &(i32, i32, dyn core::fmt::Debug) {pointer: [...], vtable: [...]}

// === CDB TESTS ===================================================================================

// cdb-command: g
Expand All @@ -34,6 +42,17 @@
// cdb-check: [+0x000] pointer : 0x[...] [Type: unsized::Foo<dyn$<core::fmt::Debug> > *]
// cdb-check: [...] vtable : 0x[...] [Type: unsigned [...]int[...] (*)[3]]

// cdb-command:dx tuple_slice
// cdb-check:tuple_slice [Type: ref$<tuple$<i32,i32,slice$<i32> > >]
// cdb-check: [+0x000] data_ptr : 0x[...] [Type: tuple$<i32,i32,slice$<i32> > *]
// cdb-check: [...] length : 0x2 [Type: unsigned [...]int[...]

// cdb-command:dx tuple_dyn
// cdb-check:tuple_dyn [Type: ref$<tuple$<i32,i32,dyn$<core::fmt::Debug> > >]
// cdb-check: [+0x000] pointer : 0x[...] [Type: tuple$<i32,i32,dyn$<core::fmt::Debug> > *]
// cdb-check: [...] vtable : 0x[...] [Type: unsigned [...]int[...] (*)[3]]

#![feature(unsized_tuple_coercion)]
#![feature(omit_gdb_pretty_printer_section)]
#![omit_gdb_pretty_printer_section]

Expand All @@ -51,6 +70,10 @@ fn main() {
let b: &Foo<Foo<[u8]>> = &foo;
let c: &Foo<dyn std::fmt::Debug> = &Foo { value: 7i32 };

// Also check unsized tuples
let tuple_slice: &(i32, i32, [i32]) = &(0, 1, [2, 3]);
let tuple_dyn: &(i32, i32, dyn std::fmt::Debug) = &(0, 1, &3u64);

zzz(); // #break
}

Expand Down