[lldb][DWARF] Generalize logic to get encoding from a DWARF Type tag

[ljmf00]

Summary

This patch generalizes the logic to represent an EncodingDataType from a DWARF tag, decoupling from the current clang-specific DAWRF parser, allowing other languages to be integrated without code duplication.

[shafik]

LGTM

[shafik]

I think b/c you are indenting the text in your summary it is treating it as code.

[ljmf00]

In D115663#3190944, @shafik wrote:

I think b/c you are indenting the text in your summary it is treating it as code.

I copied it directly from git show. I'm going to try to take care of it next time :)

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h

 
 #include "DWARFDIE.h"
 #include "DWARFDefines.h"
 #include "DWARFFormValue.h"
 #include "lldb/Core/Declaration.h"
 #include "lldb/Utility/ConstString.h"
 #include "lldb/Core/PluginInterface.h"
 #include "lldb/Symbol/SymbolFile.h"
+#include "lldb/Symbol/Type.h"
 #include "lldb/Symbol/CompilerDecl.h"
 #include "lldb/Symbol/CompilerDeclContext.h"
 #include "lldb/lldb-enumerations.h"
 
 class DWARFDIE;
 namespace lldb_private {
 class CompileUnit;
 class ExecutionContext;
virtual void EnsureAllDIEsInDeclContextHaveBeenParsed(
       lldb_private::CompilerDeclContext decl_context) = 0;
 
   static llvm::Optional<lldb_private::SymbolFile::ArrayInfo>
   ParseChildArrayInfo(const DWARFDIE &parent_die,
                       const lldb_private::ExecutionContext *exe_ctx = nullptr);
 
   static lldb::AccessType GetAccessTypeFromDWARF(uint32_t dwarf_accessibility);
 
+  static lldb_private::Type::EncodingDataType GetEncodingFromDWARFTypeTag(dw_tag_t tag);
+
   /// If \p type_sp is valid, calculate and set its symbol context scope, and
   /// update the type list for its backing symbol file.
   ///
   /// Returns \p type_sp.
   lldb::TypeSP
   UpdateSymbolContextScopeForType(const lldb_private::SymbolContext &sc,
                                   const DWARFDIE &die, lldb::TypeSP type_sp);
 };

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.cpp

TypeSP DWARFASTParser::UpdateSymbolContextScopeForType(
 
   // We are ready to put this type into the uniqued list up at the module
   // level.
   type_list.Insert(type_sp);
 
   dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
   return type_sp;
 }
+
+lldb_private::Type::EncodingDataType DWARFASTParser::GetEncodingFromDWARFTypeTag(dw_tag_t tag)
+{
+  switch(tag) {
+    case DW_TAG_pointer_type:
+      return Type::eEncodingIsPointerUID;
+    case DW_TAG_reference_type:
+      return Type::eEncodingIsLValueReferenceUID;
+    case DW_TAG_rvalue_reference_type:
+      return Type::eEncodingIsRValueReferenceUID;
+    case DW_TAG_typedef:
+      return Type::eEncodingIsTypedefUID;
+    case DW_TAG_const_type:
+      return Type::eEncodingIsConstUID;
+    case DW_TAG_restrict_type:
+      return Type::eEncodingIsRestrictUID;
+    case DW_TAG_volatile_type:
+      return Type::eEncodingIsVolatileUID;
+    case DW_TAG_atomic_type:
+      return Type::eEncodingIsAtomicUID;
+    default:
+      return Type::eEncodingIsUID;
+  }
+}

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

DWARFASTParserClang::ParseTypeModifier(const SymbolContext &sc,
                                        const DWARFDIE &die,
                                        ParsedDWARFTypeAttributes &attrs) {
   Log *log(LogChannelDWARF::GetLogIfAny(DWARF_LOG_TYPE_COMPLETION |
                                         DWARF_LOG_LOOKUPS));
   SymbolFileDWARF *dwarf = die.GetDWARF();
   const dw_tag_t tag = die.Tag();
   LanguageType cu_language = SymbolFileDWARF::GetLanguage(*die.GetCU());
   Type::ResolveState resolve_state = Type::ResolveState::Unresolved;
-  Type::EncodingDataType encoding_data_type = Type::eEncodingIsUID;
+  Type::EncodingDataType encoding_data_type = GetEncodingFromDWARFTypeTag(tag);
   TypeSP type_sp;
   CompilerType clang_type;
 
   if (tag == DW_TAG_typedef) {
     // DeclContext will be populated when the clang type is materialized in
     // Type::ResolveCompilerType.
     PrepareContextToReceiveMembers(
         m_ast, GetClangASTImporter(),
case DW_TAG_unspecified_type:
     LLVM_FALLTHROUGH;
 
   case DW_TAG_base_type:
     resolve_state = Type::ResolveState::Full;
     clang_type = m_ast.GetBuiltinTypeForDWARFEncodingAndBitSize(
         attrs.name.GetStringRef(), attrs.encoding,
         attrs.byte_size.getValueOr(0) * 8);
     break;
-
-  case DW_TAG_pointer_type:
-    encoding_data_type = Type::eEncodingIsPointerUID;
-    break;
-  case DW_TAG_reference_type:
-    encoding_data_type = Type::eEncodingIsLValueReferenceUID;
-    break;
-  case DW_TAG_rvalue_reference_type:
-    encoding_data_type = Type::eEncodingIsRValueReferenceUID;
-    break;
-  case DW_TAG_typedef:
-    encoding_data_type = Type::eEncodingIsTypedefUID;
-    break;
-  case DW_TAG_const_type:
-    encoding_data_type = Type::eEncodingIsConstUID;
-    break;
-  case DW_TAG_restrict_type:
-    encoding_data_type = Type::eEncodingIsRestrictUID;
-    break;
-  case DW_TAG_volatile_type:
-    encoding_data_type = Type::eEncodingIsVolatileUID;
-    break;
-  case DW_TAG_atomic_type:
-    encoding_data_type = Type::eEncodingIsAtomicUID;
-    break;
   }
 
   if (!clang_type && (encoding_data_type == Type::eEncodingIsPointerUID ||
                       encoding_data_type == Type::eEncodingIsTypedefUID)) {
     if (tag == DW_TAG_pointer_type) {
       DWARFDIE target_die = die.GetReferencedDIE(DW_AT_type);
 
       if (target_die.GetAttributeValueAsUnsigned(DW_AT_APPLE_block, 0)) {