Skippable v0 symbol name sections (MCP 737) Proof-of-concept impl

Cargo.lock

@@ -293,7 +293,7 @@ dependencies = [
  "libc",
  "miniz_oxide",
  "object 0.32.2",
- "rustc-demangle",
+ "rustc-demangle 0.1.24",
 ]
 
 [[package]]
@@ -840,7 +840,7 @@ dependencies = [
  "md-5",
  "miniz_oxide",
  "regex",
- "rustc-demangle",
+ "rustc-demangle 0.1.25",
 ]
 
 [[package]]
@@ -3246,7 +3246,7 @@ name = "rust-demangler"
 version = "0.0.1"
 dependencies = [
  "regex",
- "rustc-demangle",
+ "rustc-demangle 0.1.24",
 ]
 
 [[package]]
@@ -3280,6 +3280,11 @@ dependencies = [
  "rustc-std-workspace-core",
 ]
 
+[[package]]
+name = "rustc-demangle"
+version = "0.1.25"
+source = "git+https://github.com/michaelwoerister/rustc-demangle.git?branch=skip_unknown#7e674e483a7c61803edc8d59f2641a4ad52a1a30"
+
 [[package]]
 name = "rustc-hash"
 version = "1.1.0"
@@ -3551,7 +3556,7 @@ dependencies = [
  "libc",
  "measureme",
  "object 0.32.2",
- "rustc-demangle",
+ "rustc-demangle 0.1.25",
  "rustc_ast",
  "rustc_attr",
  "rustc_codegen_ssa",
@@ -4553,7 +4558,7 @@ name = "rustc_symbol_mangling"
 version = "0.0.0"
 dependencies = [
  "punycode",
- "rustc-demangle",
+ "rustc-demangle 0.1.25",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
@@ -5147,7 +5152,7 @@ dependencies = [
  "r-efi-alloc",
  "rand",
  "rand_xorshift",
- "rustc-demangle",
+ "rustc-demangle 0.1.24",
  "std_detect",
  "unwind",
  "wasi",

compiler/rustc_codegen_llvm/Cargo.toml

@@ -13,7 +13,7 @@ itertools = "0.12"
 libc = "0.2"
 measureme = "11"
 object = { version = "0.32.0", default-features = false, features = ["std", "read"] }
-rustc-demangle = "0.1.21"
+rustc-demangle = { git = "https://github.com/michaelwoerister/rustc-demangle.git", branch = "skip_unknown" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_attr = { path = "../rustc_attr" }
 rustc_codegen_ssa = { path = "../rustc_codegen_ssa" }

compiler/rustc_symbol_mangling/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 [dependencies]
 # tidy-alphabetical-start
 punycode = "0.4.0"
-rustc-demangle = "0.1.21"
+rustc-demangle = { git = "https://github.com/michaelwoerister/rustc-demangle.git", branch = "skip_unknown" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_hir = { path = "../rustc_hir" }

compiler/rustc_symbol_mangling/src/v0.rs

@@ -39,6 +39,7 @@ pub(super) fn mangle<'tcx>(
         consts: FxHashMap::default(),
         binders: vec![],
         out: String::from(prefix),
+        wrapper_level: GrammarFeatureLevel::BASE_LINE,
     };
 
     // Append `::{shim:...#0}` to shims that can coexist with a non-shim instance.
@@ -79,11 +80,13 @@ pub(super) fn mangle_typeid_for_trait_ref<'tcx>(
         consts: FxHashMap::default(),
         binders: vec![],
         out: String::new(),
+        wrapper_level: GrammarFeatureLevel::BASE_LINE,
     };
     cx.print_def_path(trait_ref.def_id(), &[]).unwrap();
     std::mem::take(&mut cx.out)
 }
 
+#[derive(Clone)]
 struct BinderLevel {
     /// The range of distances from the root of what's
     /// being printed, to the lifetimes in a binder.
@@ -98,6 +101,15 @@ struct BinderLevel {
     lifetime_depths: Range<u32>,
 }
 
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+struct GrammarFeatureLevel(usize);
+
+impl GrammarFeatureLevel {
+    const BASE_LINE: GrammarFeatureLevel = GrammarFeatureLevel(0);
+    const COMPLEX_CONST_GENERICS: GrammarFeatureLevel = GrammarFeatureLevel(1);
+}
+
+#[derive(Clone)]
 struct SymbolMangler<'tcx> {
     tcx: TyCtxt<'tcx>,
     binders: Vec<BinderLevel>,
@@ -109,6 +121,8 @@ struct SymbolMangler<'tcx> {
     paths: FxHashMap<(DefId, &'tcx [GenericArg<'tcx>]), usize>,
     types: FxHashMap<Ty<'tcx>, usize>,
     consts: FxHashMap<ty::Const<'tcx>, usize>,
+
+    wrapper_level: GrammarFeatureLevel,
 }
 
 impl<'tcx> SymbolMangler<'tcx> {
@@ -192,6 +206,75 @@ impl<'tcx> SymbolMangler<'tcx> {
 
         Ok(())
     }
+
+    fn required_feature_level_for_const(&self, ct: ty::Const<'tcx>) -> GrammarFeatureLevel {
+        let ct = ct.normalize(self.tcx, ty::ParamEnv::reveal_all());
+        match ct.kind() {
+            ty::ConstKind::Value(_) => {}
+
+            ty::ConstKind::Unevaluated(_)
+            | ty::ConstKind::Expr(_)
+            | ty::ConstKind::Param(_)
+            | ty::ConstKind::Infer(_)
+            | ty::ConstKind::Bound(..)
+            | ty::ConstKind::Placeholder(_)
+            | ty::ConstKind::Error(_) => {
+                return GrammarFeatureLevel::BASE_LINE;
+            }
+        }
+
+        let ty = ct.ty();
+
+        match ty.kind() {
+            ty::Uint(_) | ty::Int(_) | ty::Bool | ty::Char => GrammarFeatureLevel::BASE_LINE,
+            _ => GrammarFeatureLevel::COMPLEX_CONST_GENERICS,
+        }
+    }
+
+    fn wrapped(
+        &mut self,
+        level: GrammarFeatureLevel,
+        f: &mut dyn FnMut(&mut Self) -> Result<(), PrintError>,
+    ) -> Result<(), PrintError> {
+        if self.wrapper_level >= level {
+            return f(self);
+        }
+
+        self.out.push('C');
+        let backup = self.clone();
+
+        let mut digit_count = 2;
+
+        for _iteration in 0..10 {
+            self.wrapper_level = level;
+            let digit_range = self.out.len()..self.out.len() + digit_count;
+            for _ in 0..digit_count {
+                self.out.push('#');
+            }
+
+            self.out.push('_');
+
+            let start = self.out.len();
+
+            f(self)?;
+
+            let end = self.out.len();
+            let fragment_length = format!("{}", end - start);
+
+            // FIXME: Add check if any back references to interior were made. If
+            //        not, we can just shift everything without remangling.
+            if fragment_length.len() == digit_count {
+                self.out.replace_range(digit_range, &fragment_length);
+                self.wrapper_level = backup.wrapper_level;
+                return Ok(());
+            }
+
+            *self = backup.clone();
+            digit_count = fragment_length.len();
+        }
+
+        Err(PrintError::default())
+    }
 }
 
 impl<'tcx> Printer<'tcx> for SymbolMangler<'tcx> {
@@ -813,8 +896,12 @@ impl<'tcx> Printer<'tcx> for SymbolMangler<'tcx> {
                     ty.print(self)?;
                 }
                 GenericArgKind::Const(c) => {
-                    self.push("K");
-                    c.print(self)?;
+                    let required_feature_level = self.required_feature_level_for_const(c);
+
+                    self.wrapped(required_feature_level, &mut |this| {
+                        this.push("K");
+                        c.print(this)
+                    })?;
                 }
             }
         }

src/tools/coverage-dump/Cargo.toml

@@ -11,4 +11,4 @@ leb128 = "0.2.5"
 md5 = { package = "md-5" , version = "0.10.5" }
 miniz_oxide = "0.7.1"
 regex = "1.8.4"
-rustc-demangle = "0.1.23"
+rustc-demangle = { git = "https://github.com/michaelwoerister/rustc-demangle.git", branch = "skip_unknown" }

tests/ui/symbol-names/const-generics-str-demangling.stderr

@@ -1,4 +1,4 @@
-error: symbol-name(_RMCsCRATE_HASH_1cINtB<REF>_3StrKRe616263_E)
+error: symbol-name(_RMCsCRATE_HASH_1cINtB<REF>_3StrC10_KRe616263_E)
   --> $DIR/const-generics-str-demangling.rs:9:1
    |
 LL | #[rustc_symbol_name]
@@ -16,7 +16,7 @@ error: demangling-alt(<c::Str<"abc">>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs_CsCRATE_HASH_1cINtB<REF>_3StrKRe27_E)
+error: symbol-name(_RMs_CsCRATE_HASH_1cINtB<REF>_3StrC6_KRe27_E)
   --> $DIR/const-generics-str-demangling.rs:15:1
    |
 LL | #[rustc_symbol_name]
@@ -34,7 +34,7 @@ error: demangling-alt(<c::Str<"'">>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs0_CsCRATE_HASH_1cINtB<REF>_3StrKRe090a_E)
+error: symbol-name(_RMs0_CsCRATE_HASH_1cINtB<REF>_3StrC8_KRe090a_E)
   --> $DIR/const-generics-str-demangling.rs:21:1
    |
 LL | #[rustc_symbol_name]
@@ -52,7 +52,7 @@ error: demangling-alt(<c::Str<"\t\n">>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs1_CsCRATE_HASH_1cINtB<REF>_3StrKRee28882c3bc_E)
+error: symbol-name(_RMs1_CsCRATE_HASH_1cINtB<REF>_3StrC14_KRee28882c3bc_E)
   --> $DIR/const-generics-str-demangling.rs:27:1
    |
 LL | #[rustc_symbol_name]
@@ -70,7 +70,7 @@ error: demangling-alt(<c::Str<"∂ü">>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs2_CsCRATE_HASH_1cINtB<REF>_3StrKRee183a1e18390e183ade1839be18394e1839ae18390e183935fe18392e18394e1839be183a0e18398e18394e1839ae183985fe183a1e18390e18393e18398e1839ae18398_E)
+error: symbol-name(_RMs2_CsCRATE_HASH_1cINtB<REF>_3StrC140_KRee183a1e18390e183ade1839be18394e1839ae18390e183935fe18392e18394e1839be183a0e18398e18394e1839ae183985fe183a1e18390e18393e18398e1839ae18398_E)
   --> $DIR/const-generics-str-demangling.rs:33:1
    |
 LL | #[rustc_symbol_name]
@@ -88,7 +88,7 @@ error: demangling-alt(<c::Str<"საჭმელად_გემრიელი
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs3_CsCRATE_HASH_1cINtB<REF>_3StrKRef09f908af09fa688f09fa686f09f90ae20c2a720f09f90b6f09f9192e29895f09f94a520c2a720f09fa7a1f09f929bf09f929af09f9299f09f929c_E)
+error: symbol-name(_RMs3_CsCRATE_HASH_1cINtB<REF>_3StrC122_KRef09f908af09fa688f09fa686f09f90ae20c2a720f09f90b6f09f9192e29895f09f94a520c2a720f09fa7a1f09f929bf09f929af09f9299f09f929c_E)
   --> $DIR/const-generics-str-demangling.rs:39:1
    |
 LL | #[rustc_symbol_name]

tests/ui/symbol-names/const-generics-structural-demangling.stderr

@@ -1,4 +1,4 @@
-error: symbol-name(_RMCsCRATE_HASH_1cINtB<REF>_7RefByteKRh7b_E)
+error: symbol-name(_RMCsCRATE_HASH_1cINtB<REF>_7RefByteC6_KRh7b_E)
   --> $DIR/const-generics-structural-demangling.rs:13:1
    |
 LL | #[rustc_symbol_name]
@@ -16,7 +16,7 @@ error: demangling-alt(<c::RefByte<{&123}>>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs_CsCRATE_HASH_1cINtB<REF>_6RefZstKRAEE)
+error: symbol-name(_RMs_CsCRATE_HASH_1cINtB<REF>_6RefZstC4_KRAEE)
   --> $DIR/const-generics-structural-demangling.rs:23:1
    |
 LL | #[rustc_symbol_name]
@@ -34,7 +34,7 @@ error: demangling-alt(<c::RefZst<{&[]}>>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs0_CsCRATE_HASH_1cINtB<REF>_11Array3BytesKAh1_h2_h3_EE)
+error: symbol-name(_RMs0_CsCRATE_HASH_1cINtB<REF>_11Array3BytesC12_KAh1_h2_h3_EE)
   --> $DIR/const-generics-structural-demangling.rs:31:1
    |
 LL | #[rustc_symbol_name]
@@ -52,7 +52,7 @@ error: demangling-alt(<c::Array3Bytes<{[1, 2, 3]}>>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs1_CsCRATE_HASH_1cINtB<REF>_13TupleByteBoolKTh1_b0_EE)
+error: symbol-name(_RMs1_CsCRATE_HASH_1cINtB<REF>_13TupleByteBoolC9_KTh1_b0_EE)
   --> $DIR/const-generics-structural-demangling.rs:39:1
    |
 LL | #[rustc_symbol_name]
@@ -70,7 +70,7 @@ error: demangling-alt(<c::TupleByteBool<{(1, false)}>>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs2_CsCRATE_HASH_1cINtB<REF>_11OptionUsizeKVNtINtB<REF>_8MyOptionjE4NoneUE)
+error: symbol-name(_RMs2_CsCRATE_HASH_1cINtB<REF>_11OptionUsizeC27_KVNtINtB<REF>_8MyOptionjE4NoneUE)
   --> $DIR/const-generics-structural-demangling.rs:55:1
    |
 LL | #[rustc_symbol_name]
@@ -88,7 +88,7 @@ error: demangling-alt(<c::OptionUsize<{c::MyOption::<usize>::None}>>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs3_CsCRATE_HASH_1cINtB<REF>_11OptionUsizeKVNtINtB<REF>_8MyOptionjE4SomeTj0_EE)
+error: symbol-name(_RMs3_CsCRATE_HASH_1cINtB<REF>_11OptionUsizeC31_KVNtINtB<REF>_8MyOptionjE4SomeTj0_EE)
   --> $DIR/const-generics-structural-demangling.rs:63:1
    |
 LL | #[rustc_symbol_name]
@@ -106,7 +106,7 @@ error: demangling-alt(<c::OptionUsize<{c::MyOption::<usize>::Some(0)}>>)
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMs4_CsCRATE_HASH_1cINtB<REF>_4Foo_KVNtB<REF>_3FooS1sRe616263_2chc78_5sliceRAh1_h2_h3_EEE)
+error: symbol-name(_RMs4_CsCRATE_HASH_1cINtB<REF>_4Foo_C49_KVNtB<REF>_3FooS1sRe616263_2chc78_5sliceRAh1_h2_h3_EEE)
   --> $DIR/const-generics-structural-demangling.rs:77:1
    |
 LL | #[rustc_symbol_name]
@@ -124,7 +124,7 @@ error: demangling-alt(<c::Foo_<{c::Foo { s: "abc", ch: 'x', slice: &[1, 2, 3] }}
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RMsd_CsCRATE_HASH_1cINtB<REF>_4Bar_KVNtB<REF>_3BarS1xh7b_s_1xt1000_EE)
+error: symbol-name(_RMsd_CsCRATE_HASH_1cINtB<REF>_4Bar_C29_KVNtB<REF>_3BarS1xh7b_s_1xt1000_EE)
   --> $DIR/const-generics-structural-demangling.rs:93:5
    |
 LL |     #[rustc_symbol_name]