Debugger: Handle DW_TAG_GNU_template_template_param.

This is a GNU extension for identifying the case of a template parameter
that is itself a template. We don't currently make use of it, but this
allows us to parse/skip it correctly.

With this change, webcore is loadable/debuggable on x86-64 when built
with -gdwarf-4, with the caveat that ~3-4GB of RAM are currently required.

src/apps/debugger/dwarf/DebugInfoEntries.cpp

@@ -2573,6 +2573,39 @@ DIETypeUnit::Tag() const
 }
 
 
+// #pragma mark - DIETemplateTemplateParameter
+
+
+DIETemplateTemplateParameter::DIETemplateTemplateParameter()
+	:
+	fName(NULL)
+{
+}
+
+
+uint16
+DIETemplateTemplateParameter::Tag() const
+{
+	return DW_TAG_GNU_template_template_param;
+}
+
+
+const char*
+DIETemplateTemplateParameter::Name() const
+{
+	return fName;
+}
+
+
+status_t
+DIETemplateTemplateParameter::AddAttribute_name(uint16 attributeName,
+	const AttributeValue& value)
+{
+	fName = value.string;
+	return B_OK;
+}
+
+
 // #pragma mark - DIETemplateTypeParameterPack
 
 
@@ -2936,6 +2969,9 @@ DebugInfoEntryFactory::CreateDebugInfoEntry(uint16 tag, DebugInfoEntry*& _entry)
 		case DW_TAG_type_unit:
 			entry = new(std::nothrow) DIETypeUnit;
 			break;
+		case DW_TAG_GNU_template_template_param:
+			entry = new(std::nothrow) DIETemplateTemplateParameter;
+			break;
 		case DW_TAG_GNU_template_parameter_pack:
 			entry = new(std::nothrow) DIETemplateTypeParameterPack;
 			break;

src/apps/debugger/dwarf/DebugInfoEntries.h

@@ -1633,6 +1633,22 @@ public:
 };
 
 
+class DIETemplateTemplateParameter : public DIEDeclaredBase {
+public:
+								DIETemplateTemplateParameter();
+
+	virtual	uint16				Tag() const;
+
+	virtual	const char*			Name() const;
+
+	virtual	status_t			AddAttribute_name(uint16 attributeName,
+									const AttributeValue& value);
+
+private:
+			const char*			fName;
+};
+
+
 class DIETemplateTypeParameterPack : public DIEDeclaredBase {
 public:
 								DIETemplateTypeParameterPack();

src/apps/debugger/dwarf/Dwarf.h

@@ -69,6 +69,8 @@ enum {
 	DW_TAG_rvalue_reference_type	= 0x42,
 	DW_TAG_template_alias			= 0x43,
 	DW_TAG_lo_user					= 0x4080,
+	DW_TAG_GNU_template_template_param
+									= 0x4106,
 	DW_TAG_GNU_template_parameter_pack
 									= 0x4107,
 	DW_TAG_GNU_formal_parameter_pack