forked from Imagelibrary/binutils-gdb
b0dd661fa1
This patch rewrites the handling of slice types in Rust. More recent versions of the Rust compiler changed how unsized types were emitted, letting gdb inspect them more nicely. However, gdb did not do this, and in fact treated all such types as if they were slices of arrays, which is incorrect. This patch rewrites this handling and removes the restriction that unsized types must be array slices. I've added a comment explaining how unsized types are represented to rust-lang.c as well. I looked into a different approach, namely changing the DWARF reader to fix up slice types to have a dynamic type. However, the approach taken here turned out to be simpler. Tested on x86-64 Fedora 38 with a variety of Rust compiler versions. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30330
68 lines
2.1 KiB
Rust
68 lines
2.1 KiB
Rust
// Copyright (C) 2024 Free Software Foundation, Inc.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#![allow(dead_code)]
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#![allow(unused_variables)]
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#![allow(unused_assignments)]
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fn ignore<T>(x: T) { }
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// A generic struct that is unsized if T is unsized.
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pub struct MaybeUnsizedStruct<T: ?Sized> {
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pub regular: u32,
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pub rest: T,
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}
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// Same but without an ordinary part.
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pub struct MaybeUnsizedStruct2<T: ?Sized> {
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value: T,
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}
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fn main() {
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// This struct is still sized because T is a fixed-length array
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let sized_struct = &MaybeUnsizedStruct {
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regular: 23,
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rest: [5, 6, 7],
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};
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// This struct is still sized because T is sized
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let nested_sized_struct = &MaybeUnsizedStruct {
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regular: 91,
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rest: MaybeUnsizedStruct {
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regular: 23,
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rest: [5, 6, 7],
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},
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};
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// This will be a fat pointer, containing the length of the final
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// field.
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let unsized_struct: &MaybeUnsizedStruct<[u32]> = sized_struct;
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// This will also be a fat pointer, containing the length of the
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// final field.
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let nested_unsized_struct:
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&MaybeUnsizedStruct<MaybeUnsizedStruct<[u32]>> = nested_sized_struct;
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let alpha: MaybeUnsizedStruct2<[u8; 4]> = MaybeUnsizedStruct2 { value: *b"abc\0" };
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let beta: &MaybeUnsizedStruct2<[u8]> = α
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let reference = &unsized_struct;
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ignore(sized_struct); // set breakpoint here
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ignore(nested_sized_struct);
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ignore(unsized_struct);
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ignore(nested_unsized_struct);
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}
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