GNU3 demangler: fix type names to match Itanium ABI spec

- n/o: use "__int128"/"unsigned __int128" (was "int128_t"/"uint128_t")
- Dd/Df/De: use "decimal64"/"decimal32"/"decimal128" (were mapped to
  binary float types double/float/float128)
- Dp: always show "..." for pack expansion (was only shown for auto types)
- Add altName support to FloatType (DemangledTypeNode + Finalize path)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: plafosse

demangler/gnu3/demangle_gnu3.cpp

@@ -722,8 +722,8 @@ DemangledTypeNode DemangleGNU3::DemangleType()
 	case 'v': type = DemangledTypeNode::VoidType(); break;
 	case 'w': type = DemangledTypeNode::IntegerType(4, false, "wchar_t"); break; //TODO: verify
 	case 'b': type = DemangledTypeNode::BoolType(); break;
-	case 'c': type = DemangledTypeNode::IntegerType(1, true); break;
-	case 'a': type = DemangledTypeNode::IntegerType(1, true); break;
+	case 'c': type = DemangledTypeNode::IntegerType(1, true, "char"); break;
+	case 'a': type = DemangledTypeNode::IntegerType(1, true, "signed char"); break;
 	case 'h': type = DemangledTypeNode::IntegerType(1, false); break;
 	case 's': type = DemangledTypeNode::IntegerType(2, true); break;
 	case 't': type = DemangledTypeNode::IntegerType(2, false); break;
@@ -756,9 +756,9 @@ DemangledTypeNode DemangleGNU3::DemangleType()
 	case 'D':
 		switch (m_reader.Read())
 		{
-		case 'd': type = DemangledTypeNode::FloatType(8); break;
-		case 'e': type = DemangledTypeNode::FloatType(16); break;
-		case 'f': type = DemangledTypeNode::FloatType(4); break;
+		case 'd': type = DemangledTypeNode::FloatType(8, "decimal64"); break;
+		case 'e': type = DemangledTypeNode::FloatType(16, "decimal128"); break;
+		case 'f': type = DemangledTypeNode::FloatType(4, "decimal32"); break;
 		case 'h': type = DemangledTypeNode::FloatType(2); break;
 		case 'i': type = DemangledTypeNode::IntegerType(4, true, "char32_t"); break;
 		case 's': type = DemangledTypeNode::IntegerType(2, true, "char16_t"); break;
@@ -773,13 +773,7 @@ DemangledTypeNode DemangleGNU3::DemangleType()
 		case 'p':
 		{
 			DemangledTypeNode inner = DemangleType();
-			string inner_str = inner.GetString();
-			// Only show "..." for abstract pack expansions (e.g. auto&&...) not for
-			// concrete instantiations like thread_task*&& which have been fully expanded.
-			if (inner_str.find("auto") != string::npos)
-				type = CreateUnknownType(inner_str + "...");
-			else
-				type = CreateUnknownType(inner_str);
+			type = CreateUnknownType(inner.GetString() + "...");
 			break;
 		}
 		case 't':

demangler/gnu3/demangled_type_node.cpp

@@ -62,11 +62,12 @@ DemangledTypeNode DemangledTypeNode::IntegerType(size_t width, bool isSigned, co
 }
 
 
-DemangledTypeNode DemangledTypeNode::FloatType(size_t width)
+DemangledTypeNode DemangledTypeNode::FloatType(size_t width, const string& altName)
 {
 	DemangledTypeNode n;
 	n.m_typeClass = FloatTypeClass;
 	n.m_width = width;
+	n.m_altName = altName;
 	return n;
 }
 
@@ -273,7 +274,9 @@ void DemangledTypeNode::AppendBeforeName(string& out, const DemangledTypeNode* p
 		break;
 
 	case FloatTypeClass:
-		switch (m_width)
+		if (!m_altName.empty())
+			out += m_altName;
+		else switch (m_width)
 		{
 		case 2: out += "float16"; break;
 		case 4: out += "float"; break;
@@ -463,8 +466,8 @@ Ref<Type> DemangledTypeNode::Finalize() const
 	case FloatTypeClass:
 	{
 		if (!m_const && !m_volatile)
-			return Type::FloatType(m_width);
-		TypeBuilder tb = TypeBuilder::FloatType(m_width);
+			return Type::FloatType(m_width, m_altName);
+		TypeBuilder tb = TypeBuilder::FloatType(m_width, m_altName);
 		tb.SetConst(m_const);
 		tb.SetVolatile(m_volatile);
 		return tb.Finalize();

demangler/gnu3/demangled_type_node.h

@@ -72,7 +72,7 @@ class DemangledTypeNode
 	static DemangledTypeNode VoidType();
 	static DemangledTypeNode BoolType();
 	static DemangledTypeNode IntegerType(size_t width, bool isSigned, const _STD_STRING& altName = "");
-	static DemangledTypeNode FloatType(size_t width);
+	static DemangledTypeNode FloatType(size_t width, const _STD_STRING& altName = "");
 	static DemangledTypeNode VarArgsType();
 	static DemangledTypeNode PointerType(BN::Architecture* arch, DemangledTypeNode child,
 		bool cnst, bool vltl, BNReferenceType refType);