Auto merge of #57967 - eddyb:rmangle, r=michaelwoerister

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

Cargo.lock

@@ -120,7 +120,7 @@ dependencies = [
  "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-demangle 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -2023,6 +2023,11 @@ dependencies = [
  "unicase 2.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "punycode"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "quick-error"
 version = "1.2.2"
@@ -2492,7 +2497,7 @@ dependencies = [
 
 [[package]]
 name = "rustc-demangle"
-version = "0.1.10"
+version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2648,7 +2653,7 @@ dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "memmap 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-demangle 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_llvm 0.0.0",
 ]
 
@@ -2665,7 +2670,7 @@ dependencies = [
  "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
- "rustc-demangle 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_allocator 0.0.0",
  "rustc_apfloat 0.0.0",
  "rustc_codegen_utils 0.0.0",
@@ -2687,7 +2692,9 @@ version = "0.0.0"
 dependencies = [
  "flate2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "punycode 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
+ "rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_data_structures 0.0.0",
  "rustc_metadata 0.0.0",
  "rustc_mir 0.0.0",
@@ -4276,6 +4283,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum proptest 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "24f5844db2f839e97e3021980975f6ebf8691d9b9b2ca67ed3feb38dc3edb52c"
 "checksum pulldown-cmark 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d6fdf85cda6cadfae5428a54661d431330b312bc767ddbc57adbedc24da66e32"
 "checksum pulldown-cmark 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "051e60ace841b3bfecd402fe5051c06cb3bec4a6e6fdd060a37aa8eb829a1db3"
+"checksum punycode 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6ddd112cca70a4d30883b2d21568a1d376ff8be4758649f64f973c6845128ad3"
 "checksum quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9274b940887ce9addde99c4eee6b5c44cc494b182b97e73dc8ffdcb3397fd3f0"
 "checksum quine-mc_cluskey 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "07589615d719a60c8dd8a4622e7946465dfef20d1a428f969e3443e7386d5f45"
 "checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
@@ -4313,7 +4321,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum rustc-ap-serialize 407.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cf09c60aaee892b0fd107544cfe607d8d463e7f33da34aa823566b8fd2b17f53"
 "checksum rustc-ap-syntax 407.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "69f38cc120ff317678bbda8c4f58c1bbc1de64b615383ab01480482dde5e95a1"
 "checksum rustc-ap-syntax_pos 407.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "20a0a201141c5c416b1924b079eeefc7b013e34ece0740ce4997f358b3684a7f"
-"checksum rustc-demangle 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "82ae957aa1b3055d8e086486723c0ccd3d7b8fa190ae8fa2e35543b6171c810e"
+"checksum rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "a7f4dccf6f4891ebcc0c39f9b6eb1a83b9bf5d747cb439ec6fba4f3b977038af"
 "checksum rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7540fc8b0c49f096ee9c961cda096467dce8084bec6bdca2fc83895fd9b28cb8"
 "checksum rustc-rayon 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "8d98c51d9cbbe810c8b6693236d3412d8cd60513ff27a3e1b6af483dca0af544"
 "checksum rustc-rayon 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0d2e07e19601f21c59aad953c2632172ba70cb27e685771514ea66e4062b3363"

src/librustc/query/mod.rs

@@ -624,6 +624,10 @@ rustc_queries! {
             fatal_cycle
             desc { "test whether a crate has #![no_builtins]" }
         }
+        query symbol_mangling_version(_: CrateNum) -> SymbolManglingVersion {
+            fatal_cycle
+            desc { "query a crate's symbol mangling version" }
+        }
 
         query extern_crate(_: DefId) -> Option<&'tcx ExternCrate> {
             eval_always

src/librustc/session/config.rs

@@ -131,6 +131,14 @@ impl SwitchWithOptPath {
     }
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+pub enum SymbolManglingVersion {
+    Legacy,
+    V0,
+}
+
+impl_stable_hash_via_hash!(SymbolManglingVersion);
+
 #[derive(Clone, Copy, PartialEq, Hash)]
 pub enum DebugInfo {
     None,
@@ -838,11 +846,14 @@ macro_rules! options {
             Some("an optional path to the profiling data output directory");
         pub const parse_merge_functions: Option<&str> =
             Some("one of: `disabled`, `trampolines`, or `aliases`");
+        pub const parse_symbol_mangling_version: Option<&str> =
+            Some("either `legacy` or `v0` (RFC 2603)");
     }
 
     #[allow(dead_code)]
     mod $mod_set {
-        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath};
+        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath,
+            SymbolManglingVersion};
         use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
         use std::path::PathBuf;
         use std::str::FromStr;
@@ -1112,6 +1123,18 @@ macro_rules! options {
             }
             true
         }
+
+        fn parse_symbol_mangling_version(
+            slot: &mut SymbolManglingVersion,
+            v: Option<&str>,
+        ) -> bool {
+            *slot = match v {
+                Some("legacy") => SymbolManglingVersion::Legacy,
+                Some("v0") => SymbolManglingVersion::V0,
+                _ => return false,
+            };
+            true
+        }
     }
 ) }
 
@@ -1457,6 +1480,9 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "only allow the listed language features to be enabled in code (space separated)"),
     emit_artifact_notifications: bool = (false, parse_bool, [UNTRACKED],
         "emit notifications after each artifact has been output (only in the JSON format)"),
+    symbol_mangling_version: SymbolManglingVersion = (SymbolManglingVersion::Legacy,
+        parse_symbol_mangling_version, [TRACKED],
+        "which mangling version to use for symbol names"),
 }
 
 pub fn default_lib_output() -> CrateType {
@@ -2551,7 +2577,8 @@ mod dep_tracking {
     use std::path::PathBuf;
     use std::collections::hash_map::DefaultHasher;
     use super::{CrateType, DebugInfo, ErrorOutputType, OptLevel, OutputTypes,
-                Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath};
+                Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath,
+                SymbolManglingVersion};
     use syntax::feature_gate::UnstableFeatures;
     use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel, TargetTriple};
     use syntax::edition::Edition;
@@ -2620,6 +2647,7 @@ mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(Edition);
     impl_dep_tracking_hash_via_hash!(LinkerPluginLto);
     impl_dep_tracking_hash_via_hash!(SwitchWithOptPath);
+    impl_dep_tracking_hash_via_hash!(SymbolManglingVersion);
 
     impl_dep_tracking_hash_for_sortable_vec_of!(String);
     impl_dep_tracking_hash_for_sortable_vec_of!(PathBuf);
@@ -2693,7 +2721,7 @@ mod tests {
     use std::collections::{BTreeMap, BTreeSet};
     use std::iter::FromIterator;
     use std::path::PathBuf;
-    use super::{Externs, OutputType, OutputTypes};
+    use super::{Externs, OutputType, OutputTypes, SymbolManglingVersion};
     use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel};
     use syntax::symbol::sym;
     use syntax::edition::{Edition, DEFAULT_EDITION};
@@ -3367,6 +3395,10 @@ mod tests {
         opts = reference.clone();
         opts.debugging_opts.allow_features = Some(vec![String::from("lang_items")]);
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
+
+        opts = reference.clone();
+        opts.debugging_opts.symbol_mangling_version = SymbolManglingVersion::V0;
+        assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
     }
 
     #[test]

src/librustc/ty/query/mod.rs

@@ -20,7 +20,7 @@ use crate::mir::mono::CodegenUnit;
 use crate::mir;
 use crate::mir::interpret::GlobalId;
 use crate::session::CrateDisambiguator;
-use crate::session::config::{EntryFnType, OutputFilenames, OptLevel};
+use crate::session::config::{EntryFnType, OutputFilenames, OptLevel, SymbolManglingVersion};
 use crate::traits::{self, Vtable};
 use crate::traits::query::{
     CanonicalPredicateGoal, CanonicalProjectionGoal,

src/librustc_codegen_llvm/Cargo.toml

@@ -13,7 +13,7 @@ test = false
 [dependencies]
 cc = "1.0.1" # Used to locate MSVC
 num_cpus = "1.0"
-rustc-demangle = "0.1.4"
+rustc-demangle = "0.1.15"
 rustc_llvm = { path = "../librustc_llvm" }
 memmap = "0.6"
 

src/librustc_codegen_ssa/Cargo.toml

@@ -14,7 +14,7 @@ test = false
 bitflags = "1.0.4"
 cc = "1.0.1"
 num_cpus = "1.0"
-rustc-demangle = "0.1.4"
+rustc-demangle = "0.1.15"
 memmap = "0.6"
 log = "0.4.5"
 libc = "0.2.44"

src/librustc_codegen_utils/Cargo.toml

@@ -13,6 +13,8 @@ test = false
 [dependencies]
 flate2 = "1.0"
 log = "0.4"
+punycode = "0.4.0"
+rustc-demangle = "0.1.15"
 
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }

src/librustc_codegen_utils/lib.rs

@@ -7,7 +7,9 @@
 #![feature(arbitrary_self_types)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
+#![feature(core_intrinsics)]
 #![feature(custom_attribute)]
+#![feature(never_type)]
 #![feature(nll)]
 #![allow(unused_attributes)]
 #![feature(rustc_diagnostic_macros)]