Demangle Rust's Y<type><path> production for passably simple <type>s.
PiperOrigin-RevId: 633229582
Change-Id: Ibda908d261b52b1af766304992edd77a5bdd56b5
diff --git a/absl/debugging/internal/demangle_rust.cc b/absl/debugging/internal/demangle_rust.cc
index 7086cab..f2a411d 100644
--- a/absl/debugging/internal/demangle_rust.cc
+++ b/absl/debugging/internal/demangle_rust.cc
@@ -37,6 +37,33 @@
bool IsAlpha(char c) { return IsLower(c) || IsUpper(c); }
bool IsIdentifierChar(char c) { return IsAlpha(c) || IsDigit(c) || c == '_'; }
+const char* BasicTypeName(char c) {
+ switch (c) {
+ case 'a': return "i8";
+ case 'b': return "bool";
+ case 'c': return "char";
+ case 'd': return "f64";
+ case 'e': return "str";
+ case 'f': return "f32";
+ case 'h': return "u8";
+ case 'i': return "isize";
+ case 'j': return "usize";
+ case 'l': return "i32";
+ case 'm': return "u32";
+ case 'n': return "i128";
+ case 'o': return "u128";
+ case 'p': return "_";
+ case 's': return "i16";
+ case 't': return "u16";
+ case 'u': return "()";
+ case 'v': return "...";
+ case 'x': return "i64";
+ case 'y': return "u64";
+ case 'z': return "!";
+ }
+ return nullptr;
+}
+
// Parser for Rust symbol mangling v0, whose grammar is defined here:
//
// https://doc.rust-lang.org/rustc/symbol-mangling/v0.html#symbol-grammar-summary
@@ -115,12 +142,16 @@
// path -> crate-root | inherent-impl | trait-impl | trait-definition |
// nested-path | generic-args | backref
+ //
+ // Note that ABSL_DEMANGLER_RECURSE does not work inside a nested switch
+ // (which would hide the generated case label). Thus we jump out of the
+ // inner switch with gotos before performing any fake recursion.
path:
switch (Take()) {
case 'C': goto crate_root;
case 'M': return false; // inherent-impl not yet implemented
case 'X': return false; // trait-impl not yet implemented
- case 'Y': return false; // trait-definition not yet implemented
+ case 'Y': goto trait_definition;
case 'N': goto nested_path;
case 'I': return false; // generic-args not yet implemented
case 'B': return false; // backref not yet implemented
@@ -132,7 +163,16 @@
if (!ParseIdentifier()) return false;
continue;
- // nested-path -> N namespace path identifier (N consumed above)
+ // trait-definition -> Y type path (Y already consumed)
+ trait_definition:
+ if (!Emit("<")) return false;
+ ABSL_DEMANGLER_RECURSE(type, kTraitDefinitionInfix);
+ if (!Emit(" as ")) return false;
+ ABSL_DEMANGLER_RECURSE(path, kTraitDefinitionEnding);
+ if (!Emit(">")) return false;
+ continue;
+
+ // nested-path -> N namespace path identifier (N already consumed)
// namespace -> lower | upper
nested_path:
// Uppercase namespaces must be saved on the stack so we can print
@@ -156,6 +196,98 @@
// Neither upper or lower
return false;
+
+ // type -> basic-type | array-type | slice-type | tuple-type |
+ // ref-type | mut-ref-type | const-ptr-type | mut-ptr-type |
+ // fn-type | dyn-trait-type | path | backref
+ //
+ // We use ifs instead of switch (Take()) because the default case jumps
+ // to path, which will need to see the first character not yet Taken
+ // from the input. Because we do not use a nested switch here,
+ // ABSL_DEMANGLER_RECURSE works fine in the 'S' case.
+ type:
+ if (IsLower(Peek())) {
+ const char* type_name = BasicTypeName(Take());
+ if (type_name == nullptr || !Emit(type_name)) return false;
+ continue;
+ }
+ if (Eat('A')) return false; // array-type not yet implemented
+ if (Eat('S')) {
+ if (!Emit("[")) return false;
+ ABSL_DEMANGLER_RECURSE(type, kSliceEnding);
+ if (!Emit("]")) return false;
+ continue;
+ }
+ if (Eat('T')) goto tuple_type;
+ if (Eat('R')) {
+ if (!Emit("&")) return false;
+ if (Eat('L')) return false; // lifetime not yet implemented
+ goto type;
+ }
+ if (Eat('Q')) {
+ if (!Emit("&mut ")) return false;
+ if (Eat('L')) return false; // lifetime not yet implemented
+ goto type;
+ }
+ if (Eat('P')) {
+ if (!Emit("*const ")) return false;
+ goto type;
+ }
+ if (Eat('O')) {
+ if (!Emit("*mut ")) return false;
+ goto type;
+ }
+ if (Eat('F')) return false; // fn-type not yet implemented
+ if (Eat('D')) return false; // dyn-trait-type not yet implemented
+ if (Eat('B')) return false; // backref not yet implemented
+ goto path;
+
+ // tuple-type -> T type* E (T already consumed)
+ tuple_type:
+ if (!Emit("(")) return false;
+
+ // The toolchain should call the unit type u instead of TE, but the
+ // grammar and other demanglers also recognize TE, so we do too.
+ if (Eat('E')) {
+ if (!Emit(")")) return false;
+ continue;
+ }
+
+ // A tuple with one element is rendered (type,) instead of (type).
+ ABSL_DEMANGLER_RECURSE(type, kAfterFirstTupleElement);
+ if (Eat('E')) {
+ if (!Emit(",)")) return false;
+ continue;
+ }
+
+ // A tuple with two elements is of course (x, y).
+ if (!Emit(", ")) return false;
+ ABSL_DEMANGLER_RECURSE(type, kAfterSecondTupleElement);
+ if (Eat('E')) {
+ if (!Emit(")")) return false;
+ continue;
+ }
+
+ // And (x, y, z) for three elements.
+ if (!Emit(", ")) return false;
+ ABSL_DEMANGLER_RECURSE(type, kAfterThirdTupleElement);
+ if (Eat('E')) {
+ if (!Emit(")")) return false;
+ continue;
+ }
+
+ // For longer tuples we write (x, y, z, ...), printing none of the
+ // content of the fourth and later types. Thus we avoid exhausting
+ // output buffers and human readers' patience when some library has a
+ // long tuple as an implementation detail, without having to
+ // completely obfuscate all tuples.
+ if (!Emit(", ...)")) return false;
+ ++silence_depth_;
+ while (!Eat('E')) {
+ ABSL_DEMANGLER_RECURSE(type, kAfterSubsequentTupleElement);
+ }
+ --silence_depth_;
+ continue;
}
}
@@ -169,6 +301,13 @@
kVendorSpecificSuffix,
kIdentifierInUppercaseNamespace,
kIdentifierInLowercaseNamespace,
+ kTraitDefinitionInfix,
+ kTraitDefinitionEnding,
+ kSliceEnding,
+ kAfterFirstTupleElement,
+ kAfterSecondTupleElement,
+ kAfterThirdTupleElement,
+ kAfterSubsequentTupleElement,
};
// Element count for the stack_ array. A larger kStackSize accommodates more
@@ -320,6 +459,8 @@
// Emit the beginnings of braced forms like {shim:vtable#0}.
if (uppercase_namespace == '\0') {
+ // Decoding of Punycode is not yet implemented. For now we emit
+ // "{Punycode ...}" with the raw encoding inside.
if (is_punycoded && !Emit("{Punycode ")) return false;
} else {
switch (uppercase_namespace) {
diff --git a/absl/debugging/internal/demangle_rust.h b/absl/debugging/internal/demangle_rust.h
index 8e9060b..1c19815 100644
--- a/absl/debugging/internal/demangle_rust.h
+++ b/absl/debugging/internal/demangle_rust.h
@@ -33,10 +33,8 @@
// call-stack space. It is suitable for symbolizing stack traces in a signal
// handler.
//
-// The demangling logic is under development. In this version of Abseil,
-// DemangleRustSymbolEncoding parses a few simple kinds of symbol names, but
-// nothing having backreferences in the input or angle brackets in the
-// demangling, and it emits raw Punycode instead of the UTF-8 represented by it.
+// The demangling logic is under development; search for "not yet implemented"
+// in the .cc file to see where the gaps are.
bool DemangleRustSymbolEncoding(const char* mangled, char* out,
std::size_t out_size);
diff --git a/absl/debugging/internal/demangle_rust_test.cc b/absl/debugging/internal/demangle_rust_test.cc
index 2841576..d42700f 100644
--- a/absl/debugging/internal/demangle_rust_test.cc
+++ b/absl/debugging/internal/demangle_rust_test.cc
@@ -209,6 +209,90 @@
"crate_name::{Y:y#2}::{X:x#3}::{closure#4}");
}
+TEST(DemangleRust, TraitDefinition) {
+ EXPECT_DEMANGLING(
+ "_RNvYNvC7crate_a9my_structNvC7crate_b8my_trait1f",
+ "<crate_a::my_struct as crate_b::my_trait>::f");
+}
+
+TEST(DemangleRust, BasicTypeNames) {
+ EXPECT_DEMANGLING("_RNvYaNvC1c1t1f", "<i8 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYbNvC1c1t1f", "<bool as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYcNvC1c1t1f", "<char as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYdNvC1c1t1f", "<f64 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYeNvC1c1t1f", "<str as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYfNvC1c1t1f", "<f32 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYhNvC1c1t1f", "<u8 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYiNvC1c1t1f", "<isize as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYjNvC1c1t1f", "<usize as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYlNvC1c1t1f", "<i32 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYmNvC1c1t1f", "<u32 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYnNvC1c1t1f", "<i128 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYoNvC1c1t1f", "<u128 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYpNvC1c1t1f", "<_ as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYsNvC1c1t1f", "<i16 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYtNvC1c1t1f", "<u16 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYuNvC1c1t1f", "<() as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYvNvC1c1t1f", "<... as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYxNvC1c1t1f", "<i64 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYyNvC1c1t1f", "<u64 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYzNvC1c1t1f", "<! as c::t>::f");
+
+ EXPECT_DEMANGLING_FAILS("_RNvYkNvC1c1t1f");
+}
+
+TEST(DemangleRust, SliceTypes) {
+ EXPECT_DEMANGLING("_RNvYSlNvC1c1t1f", "<[i32] as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYSNvC1d1sNvC1c1t1f", "<[d::s] as c::t>::f");
+}
+
+TEST(DemangleRust, ImmutableReferenceTypes) {
+ EXPECT_DEMANGLING("_RNvYRlNvC1c1t1f", "<&i32 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYRNvC1d1sNvC1c1t1f", "<&d::s as c::t>::f");
+}
+
+TEST(DemangleRust, MutableReferenceTypes) {
+ EXPECT_DEMANGLING("_RNvYQlNvC1c1t1f", "<&mut i32 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYQNvC1d1sNvC1c1t1f", "<&mut d::s as c::t>::f");
+}
+
+TEST(DemangleRust, ConstantRawPointerTypes) {
+ EXPECT_DEMANGLING("_RNvYPlNvC1c1t1f", "<*const i32 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYPNvC1d1sNvC1c1t1f", "<*const d::s as c::t>::f");
+}
+
+TEST(DemangleRust, MutableRawPointerTypes) {
+ EXPECT_DEMANGLING("_RNvYOlNvC1c1t1f", "<*mut i32 as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYONvC1d1sNvC1c1t1f", "<*mut d::s as c::t>::f");
+}
+
+TEST(DemangleRust, TupleLength0) {
+ EXPECT_DEMANGLING("_RNvYTENvC1c1t1f", "<() as c::t>::f");
+}
+
+TEST(DemangleRust, TupleLength1) {
+ EXPECT_DEMANGLING("_RNvYTlENvC1c1t1f", "<(i32,) as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYTNvC1d1sENvC1c1t1f", "<(d::s,) as c::t>::f");
+}
+
+TEST(DemangleRust, TupleLength2) {
+ EXPECT_DEMANGLING("_RNvYTlmENvC1c1t1f", "<(i32, u32) as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYTNvC1d1xNvC1e1yENvC1c1t1f",
+ "<(d::x, e::y) as c::t>::f");
+}
+
+TEST(DemangleRust, TupleLength3) {
+ EXPECT_DEMANGLING("_RNvYTlmnENvC1c1t1f", "<(i32, u32, i128) as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYTNvC1d1xNvC1e1yNvC1f1zENvC1c1t1f",
+ "<(d::x, e::y, f::z) as c::t>::f");
+}
+
+TEST(DemangleRust, LongerTuplesAbbreviated) {
+ EXPECT_DEMANGLING("_RNvYTlmnoENvC1c1t1f",
+ "<(i32, u32, i128, ...) as c::t>::f");
+ EXPECT_DEMANGLING("_RNvYTlmnNvC1d1xNvC1e1yENvC1c1t1f",
+ "<(i32, u32, i128, ...) as c::t>::f");
+}
} // namespace
} // namespace debugging_internal
