[demangler] Add co_await demangling

The demangler doesn't understand 'aw' as an operator name. This adds
the necessary smarts -- you may use this as an operator functionname,
but not as an expression operator.

Reviewed By: ChuanqiXu

Differential Revision: https://reviews.llvm.org/D120143

libcxxabi/src/demangle/ItaniumDemangle.h

@@ -2568,6 +2568,7 @@ template <typename Derived, typename Alloc> struct AbstractManglingParser {
       Call,        // Function call: expr (expr*)
       CCast,       // C cast: (type)expr
       Conditional, // Conditional: expr ? expr : expr
+      NameOnly,    // Overload only, not allowed in expression.
       // Below do not have operator names
       NamedCast, // Named cast, @<type>(expr)
       OfIdOp,    // alignof, sizeof, typeid
@@ -2877,6 +2878,7 @@ AbstractManglingParser<Derived, Alloc>::parseOperatorEncoding() {
       {"ad", OperatorInfo::Prefix, false, "operator&"},
       {"an", OperatorInfo::Binary, false, "operator&"},
       {"at", OperatorInfo::OfIdOp, /*Type*/ true, "alignof ("},
+      {"aw", OperatorInfo::NameOnly, false, "operator co_await"},
       {"az", OperatorInfo::OfIdOp, /*Type*/ false, "alignof ("},
       {"cc", OperatorInfo::NamedCast, false, "const_cast"},
       {"cl", OperatorInfo::Call, false, "operator()"},
@@ -4573,6 +4575,10 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExpr() {
         return nullptr;
       return make<EnclosingExpr>(Sym, Arg, ")");
     }
+    case OperatorInfo::NameOnly: {
+      // Not valid as an expression operand.
+      return nullptr;
+    }
     }
     DEMANGLE_UNREACHABLE;
   }

libcxxabi/test/test_demangle.pass.cpp

@@ -29865,6 +29865,8 @@ const char* cases[][2] =
     {"_ZN2FnIXdlLj4EEXgsdaLj4EEEEvv", "void Fn<delete 4u, ::delete[] 4u>()"},
 
     {"_Z3TPLIiET_S0_", "int TPL<int>(int)"},
+
+    {"_ZN1XawEv", "X::operator co_await()"},
 };
 
 const unsigned N = sizeof(cases) / sizeof(cases[0]);
@@ -29950,6 +29952,8 @@ const char* invalid_cases[] =
 
     "_ZN1fIiEEvNTUt_E",
     "_ZNDTUt_Ev",
+
+    "_ZN1fIXawLi0EEEEvv",
 };
 
 const unsigned NI = sizeof(invalid_cases) / sizeof(invalid_cases[0]);

llvm/include/llvm/Demangle/ItaniumDemangle.h

@@ -2568,6 +2568,7 @@ template <typename Derived, typename Alloc> struct AbstractManglingParser {
       Call,        // Function call: expr (expr*)
       CCast,       // C cast: (type)expr
       Conditional, // Conditional: expr ? expr : expr
+      NameOnly,    // Overload only, not allowed in expression.
       // Below do not have operator names
       NamedCast, // Named cast, @<type>(expr)
       OfIdOp,    // alignof, sizeof, typeid
@@ -2877,6 +2878,7 @@ AbstractManglingParser<Derived, Alloc>::parseOperatorEncoding() {
       {"ad", OperatorInfo::Prefix, false, "operator&"},
       {"an", OperatorInfo::Binary, false, "operator&"},
       {"at", OperatorInfo::OfIdOp, /*Type*/ true, "alignof ("},
+      {"aw", OperatorInfo::NameOnly, false, "operator co_await"},
       {"az", OperatorInfo::OfIdOp, /*Type*/ false, "alignof ("},
       {"cc", OperatorInfo::NamedCast, false, "const_cast"},
       {"cl", OperatorInfo::Call, false, "operator()"},
@@ -4573,6 +4575,10 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExpr() {
         return nullptr;
       return make<EnclosingExpr>(Sym, Arg, ")");
     }
+    case OperatorInfo::NameOnly: {
+      // Not valid as an expression operand.
+      return nullptr;
+    }
     }
     DEMANGLE_UNREACHABLE;
   }