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Support demangling the new Rust mangling scheme (v0). #23

Merged
merged 4 commits into from Apr 12, 2019
Merged

Support demangling the new Rust mangling scheme (v0). #23

merged 4 commits into from Apr 12, 2019

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eddyb
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@eddyb eddyb commented Jan 29, 2019 •
edited

This PR complements rust-lang/rust#57967 (ideally, they should be reviewed/merged in tandem).
See rust-lang/rfcs#2603 (comment) for details on the implemented mangling scheme.

Aside from testing on every symbol from a Rust stage1 build (of std, rustc and cargo), I've also confirmed this builds with Rust 1.6 (AFAICT the earliest stable version supporting #![no_std]).

There are some debatable decisions, such as the value of SMALL_PUNYCODE_LEN, or how to print certain details, I'm not sure whether this PR or the RFC is a good place to discuss those.

cc @nikomatsakis @michaelwoerister

This was referenced Jan 29, 2019
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bors added a commit to rust-lang/rust that referenced this pull request Jan 29, 2019
@bors
Auto merge of #57967 - eddyb:rmangle, r=<try>
20533a4 
Introduce Rust symbol mangling scheme.

This is an implementation of a "feature-complete" Rust mangling scheme, in the vein of rust-lang/rfcs#2603 - but with some differences, see rust-lang/rfcs#2603 (comment) for details.

The demangling implementation PR is rust-lang/rustc-demangle#23
(this PR already uses it via a git dependency, to allow testing).

Discussion of the *design* of the mangling scheme should still happen on the RFC, but this PR's specific implementation details can be reviewed in parallel.

<hr/>

*Notes for reviewers*:
* only the last 4 commits are specific to this branch, if necessary I can open a separate PR for everything else (it was meant to be its own small refactoring, but it got a bit out of hand)
* the "TEMPORARY" commit is only there because it does some extra validation (comparing the demangling from `rustc-demangle` to the compiler's pretty-printing, adjusted slightly to produce the same output), that I would like to try on crater
* there is the question of whether we should turn on the new mangling now, wait for tools to support it (I'm working on that), and/or have it under a `-Z` flag for now

r? @nikomatsakis / @michaelwoerister cc @rust-lang/compiler
@alexcrichton
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This looks fantastic to me, thanks so much for doing this @eddyb! No need to get it working that far back, but works either way :)

I'll give the new pieces a closer review as well when the Rust PR is closer to landing

bors added a commit to rust-lang/rust that referenced this pull request Jan 29, 2019
@bors
Auto merge of #57967 - eddyb:rmangle, r=<try>
7fea022 
Introduce Rust symbol mangling scheme.

This is an implementation of a "feature-complete" Rust mangling scheme, in the vein of rust-lang/rfcs#2603 - but with some differences, see rust-lang/rfcs#2603 (comment) for details.

The demangling implementation PR is rust-lang/rustc-demangle#23
(this PR already uses it via a git dependency, to allow testing).

Discussion of the *design* of the mangling scheme should still happen on the RFC, but this PR's specific implementation details can be reviewed in parallel.

<hr/>

*Notes for reviewers*:
* only the last 6 commits are specific to this branch, if necessary I can open a separate PR for everything else (it was meant to be its own small refactoring, but it got a bit out of hand)
* the "TEMPORARY" commit is only there because it does some extra validation (comparing the demangling from `rustc-demangle` to the compiler's pretty-printing, adjusted slightly to produce the same output), that I would like to try on crater
* there is the question of whether we should turn on the new mangling now, wait for tools to support it (I'm working on that), and/or have it under a `-Z` flag for now

r? @nikomatsakis / @michaelwoerister cc @rust-lang/compiler
@eddyb
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eddyb commented Apr 11, 2019

@alexcrichton We want to land the PR soon, and I've updated the naming of the new mangling scheme from modern to v0 (see rust-lang/rust#57967 (comment)).

I don't think I want to change it any further now, so it should be fine to review now.

@alexcrichton
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The code all here looks great to me, thanks again for this @eddyb!

My main comment would be that I don't really know how to verify the correctness of this or otherwise take a look at a reference somewhere. Is there reference documentation to put somewhere? Or otherwise could comments be inserted in the code namely around some match statements and such?

Other than that I think this is good to merge and publish!

@eddyb
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eddyb commented Apr 12, 2019

@alexcrichton So rust-lang/rfcs#2603 (comment) has a grammar for this mangling scheme, which @michaelwoerister added to the RFC itself, and I could put comments on relevant functions containing the respective grammar rules, if you think it would help.

@eddyb
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eddyb commented Apr 12, 2019 •
edited

As for correctness: this implementation was verified against an expected demangling (see the dump.rs file added by a commit, and removed by another, in rust-lang/rust#57967), over std+rustc+Cargo (locally) and then all of crater. Some bugs were found, but mostly/only in the compiler side, IIRC.

Also, a C implementation (which we might want to host in this repo, not sure) was also verified against the stc+rustc+Cargo dataset (1M symbols), and found to produce identical results.

EDIT: none of this, of course, means the mangler+demangler obey the spec, only that if one of them does, the other one likely does too.

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Ok that all sounds good to me, thanks!

@alexcrichton alexcrichton merged commit 1c50dca into rust-lang:master Apr 12, 2019
bors added a commit to rust-lang/rust that referenced this pull request May 31, 2019
@bors
Auto merge of #57967 - eddyb:rmangle, r=michaelwoerister
7840a0b 
Introduce Rust symbol mangling scheme.

This is an implementation of a "feature-complete" Rust mangling scheme, in the vein of rust-lang/rfcs#2603 ~~- but with some differences, see rust-lang/rfcs#2603 (comment) for details~~ (@michaelwoerister integrated my proposed changes into the RFC itself).

On nightly, you can now control the mangling scheme with `-Z symbol-mangling-version`, which can be:
* `legacy`: the older mangling version, still the default currently
* `v0`: the new RFC mangling version, as implemented by this PR

To test the new mangling, set `RUSTFLAGS=-Zsymbol-mangling-version=v0` (or change [`rustflags` in `.cargo/config.toml`](https://doc.rust-lang.org/cargo/reference/config.html#configuration-keys)). Please note that only symbols from crates built with that flag will use the new mangling, and that tool support (e.g. debuggers) will be limited initially, and it may take a while for everything to be upstreamed. However, `RUST_BACKTRACE` should work out of the box with either mangling version.

<hr/>

The demangling implementation PR is rust-lang/rustc-demangle#23
~~(this PR already uses it via a git dependency, to allow testing)~~.

Discussion of the *design* of the mangling scheme should still happen on the RFC, but this PR's specific implementation details can be reviewed in parallel.

*Notes for reviewers*:
* ~~only the last 6 commits are specific to this branch, if necessary I can open a separate PR for everything else (it was meant to be its own small refactoring, but it got a bit out of hand)~~
~~based on #58140~~
* the "harness" commit is only there because it does some extra validation (comparing the demangling from `rustc-demangle` to the compiler's pretty-printing, adjusted slightly to produce the same output), that I would like to try on crater
* ~~there is the question of whether we should turn on the new mangling now, wait for tools to support it (I'm working on that), and/or have it under a `-Z` flag for now~~ (we're gating this on `-Z symbol-mangling-version=v0`, see above)

r? @nikomatsakis / @michaelwoerister cc @rust-lang/compiler
@cuviper cuviper mentioned this pull request Jun 11, 2019
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@eddyb eddyb changed the title Support demangling the new Rust mangling scheme. Support demangling the new Rust mangling scheme (v0). Mar 13, 2020
@Centril Centril mentioned this pull request Mar 13, 2020
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kraj pushed a commit to kraj/gcc that referenced this pull request Nov 13, 2020
@eddyb @jwakely
libiberty: Support the new ("v0") mangling scheme in rust-demangle
8409649 
This is the libiberty (mainly for binutils/gdb) counterpart of
rust-lang/rustc-demangle#23.

Relevant links for the new Rust mangling scheme (aka "v0"):
* Rust RFC: rust-lang/rfcs#2603
* tracking issue: rust-lang/rust#60705
* implementation: rust-lang/rust#57967

This implementation includes full support for UTF-8 identifiers
via punycode, so I've included a testcase for that as well.

libiberty/ChangeLog:
	* rust-demangle.c (struct rust_demangler): Add
	skipping_printing and bound_lifetime_depth fields.
	(eat): Add (v0-only).
	(parse_integer_62): Add (v0-only).
	(parse_opt_integer_62): Add (v0-only).
	(parse_disambiguator): Add (v0-only).
	(struct rust_mangled_ident): Add punycode{,_len} fields.
	(parse_ident): Support v0 identifiers.
	(print_str): Respect skipping_printing.
	(print_uint64): Add (v0-only).
	(print_uint64_hex): Add (v0-only).
	(print_ident): Respect skipping_printing,
	Support v0 identifiers.
	(print_lifetime_from_index): Add (v0-only).
	(demangle_binder): Add (v0-only).
	(demangle_path): Add (v0-only).
	(demangle_generic_arg): Add (v0-only).
	(demangle_type): Add (v0-only).
	(demangle_path_maybe_open_generics): Add (v0-only).
	(demangle_dyn_trait): Add (v0-only).
	(demangle_const): Add (v0-only).
	(demangle_const_uint): Add (v0-only).
	(basic_type): Add (v0-only).
	(rust_demangle_callback): Support v0 symbols.
	* testsuite/rust-demangle-expected: Add v0 testcases.
saagarjha pushed a commit to ahjragaas/binutils-gdb that referenced this pull request Jan 16, 2021
@eddyb @tromey
libiberty: Support the new ("v0") mangling scheme in rust-demangle
f42f69f 
This is the libiberty (mainly for binutils/gdb) counterpart of
rust-lang/rustc-demangle#23.

Relevant links for the new Rust mangling scheme (aka "v0"):
* Rust RFC: rust-lang/rfcs#2603
* tracking issue: rust-lang/rust#60705
* implementation: rust-lang/rust#57967

This implementation includes full support for UTF-8 identifiers
via punycode, so I've included a testcase for that as well.

libiberty/ChangeLog
2021-01-16  Eduard-Mihai Burtescu  <eddyb@lyken.rs>

	* rust-demangle.c (struct rust_demangler): Add
	skipping_printing and bound_lifetime_depth fields.
	(eat): Add (v0-only).
	(parse_integer_62): Add (v0-only).
	(parse_opt_integer_62): Add (v0-only).
	(parse_disambiguator): Add (v0-only).
	(struct rust_mangled_ident): Add punycode{,_len} fields.
	(parse_ident): Support v0 identifiers.
	(print_str): Respect skipping_printing.
	(print_uint64): Add (v0-only).
	(print_uint64_hex): Add (v0-only).
	(print_ident): Respect skipping_printing,
	Support v0 identifiers.
	(print_lifetime_from_index): Add (v0-only).
	(demangle_binder): Add (v0-only).
	(demangle_path): Add (v0-only).
	(demangle_generic_arg): Add (v0-only).
	(demangle_type): Add (v0-only).
	(demangle_path_maybe_open_generics): Add (v0-only).
	(demangle_dyn_trait): Add (v0-only).
	(demangle_const): Add (v0-only).
	(demangle_const_uint): Add (v0-only).
	(basic_type): Add (v0-only).
	(rust_demangle_callback): Support v0 symbols.
	* testsuite/rust-demangle-expected: Add v0 testcases.
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@eddyb @alexcrichton