[lldb][NFCI] Redefine dw_attr_t typedef with llvm::dwarf::Attribute

[bulbazord]

Summary

Similar to dw_form_t, dw_attr_t is typedef'd to be a uint16_t. LLVM
defines their type llvm::dwarf::Attribute as an enum backed by a
uint16_t. Switching to the LLVM type buys us type checking and the
requirement of explicit casts.

[fdeazeve]

LGTM! Sorry for the delay!

lldb/include/lldb/Core/dwarf.h

 #include "llvm/BinaryFormat/Dwarf.h"
 
 namespace lldb_private {
 namespace dwarf {
   using namespace llvm::dwarf;
 }
 }
 
-typedef uint16_t dw_attr_t;
+typedef llvm::dwarf::Attribute dw_attr_t;
 typedef llvm::dwarf::Form dw_form_t;
 typedef llvm::dwarf::Tag dw_tag_t;
 typedef uint64_t dw_addr_t; // Dwarf address define that must be big enough for
                             // any addresses in the compile units that get
                             // parsed
 
 typedef uint64_t dw_offset_t; // Dwarf Debug Information Entry offset for any
                               // offset into the file

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

ParsedDWARFTypeAttributes::ParsedDWARFTypeAttributes(const DWARFDIE &die) {
   DWARFAttributes attributes;
   size_t num_attributes = die.GetAttributes(attributes);
   for (size_t i = 0; i < num_attributes; ++i) {
     dw_attr_t attr = attributes.AttributeAtIndex(i);
     DWARFFormValue form_value;
     if (!attributes.ExtractFormValueAtIndex(i, form_value))
       continue;
     switch (attr) {
+    default:
+      break;
     case DW_AT_abstract_origin:
       abstract_origin = form_value;
       break;
 
     case DW_AT_accessibility:
       accessibility = DWARFASTParser::GetAccessTypeFromDWARF(form_value.Unsigned());
       break;
 

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

DWARFAbbreviationDeclaration::extract(const DWARFDataExtractor &data,
   m_tag = static_cast<dw_tag_t>(data.GetULEB128(offset_ptr));
   if (m_tag == DW_TAG_null)
     return llvm::make_error<llvm::object::GenericBinaryError>(
         "abbrev decl requires non-null tag.");
 
   m_has_children = data.GetU8(offset_ptr);
 
   while (data.ValidOffset(*offset_ptr)) {
-    dw_attr_t attr = data.GetULEB128(offset_ptr);
+    auto attr = static_cast<dw_attr_t>(data.GetULEB128(offset_ptr));
     auto form = static_cast<dw_form_t>(data.GetULEB128(offset_ptr));
 
     // This is the last attribute for this abbrev decl, but there may still be
     // more abbrev decls, so return MoreItems to indicate to the caller that
     // they should call this function again.
     if (!attr && !form)
       return DWARFEnumState::MoreItems;
 

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

void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
   }
 
   for (size_t i = 0; i < num_attributes; ++i) {
     dw_attr_t attr = attributes.AttributeAtIndex(i);
     DWARFFormValue form_value;
     if (!attributes.ExtractFormValueAtIndex(i, form_value))
       continue;
     switch (attr) {
+    default:
+      break;
     case DW_AT_loclists_base:
       SetLoclistsBase(form_value.Unsigned());
       break;
     case DW_AT_rnglists_base:
       SetRangesBase(form_value.Unsigned());
       break;
     case DW_AT_str_offsets_base:
       SetStrOffsetsBase(form_value.Unsigned());

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

for (const DWARFDebugInfoEntry &die : unit.dies()) {
 
     DWARFFormValue specification_die_form;
     const size_t num_attributes = die.GetAttributes(&unit, attributes);
     if (num_attributes > 0) {
       for (uint32_t i = 0; i < num_attributes; ++i) {
         dw_attr_t attr = attributes.AttributeAtIndex(i);
         DWARFFormValue form_value;
         switch (attr) {
+        default:
+          break;
         case DW_AT_name:
           if (attributes.ExtractFormValueAtIndex(i, form_value))
             name = form_value.AsCString();
           break;
 
         case DW_AT_declaration:
           if (attributes.ExtractFormValueAtIndex(i, form_value))
             is_declaration = form_value.Unsigned() != 0;