[LLVM][DWARF] Chnage order for .debug_names abbrev print out (llvm#80229)

This stemps from conversatin in:
llvm#77457 (comment).
Right now Abbrev code for abbrev is combination of DIE TAG and other
attributes.
In the future it will be changed to be an index. Since DenseSet does not
preserve an order, added a sort based on abbrev code. Once change to
index is
made, it will print out abbrevs in the order they are stored.

Author: ayermolo

llvm/include/llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h

@@ -412,13 +412,15 @@ class DWARFDebugNames : public DWARFAcceleratorTable {
 
   /// Abbreviation describing the encoding of Name Index entries.
   struct Abbrev {
-    uint32_t Code;  ///< Abbreviation code
+    uint64_t AbbrevOffset; /// < Abbreviation offset in the .debug_names section
+    uint32_t Code;         ///< Abbreviation code
     dwarf::Tag Tag; ///< Dwarf Tag of the described entity.
     std::vector<AttributeEncoding> Attributes; ///< List of index attributes.
 
-    Abbrev(uint32_t Code, dwarf::Tag Tag,
+    Abbrev(uint32_t Code, dwarf::Tag Tag, uint64_t AbbrevOffset,
            std::vector<AttributeEncoding> Attributes)
-        : Code(Code), Tag(Tag), Attributes(std::move(Attributes)) {}
+        : AbbrevOffset(AbbrevOffset), Code(Code), Tag(Tag),
+          Attributes(std::move(Attributes)) {}
 
     void dump(ScopedPrinter &W) const;
   };

llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp

@@ -493,7 +493,7 @@ static bool isSentinel(const DWARFDebugNames::AttributeEncoding &AE) {
 }
 
 static DWARFDebugNames::Abbrev sentinelAbbrev() {
-  return DWARFDebugNames::Abbrev(0, dwarf::Tag(0), {});
+  return DWARFDebugNames::Abbrev(0, dwarf::Tag(0), 0, {});
 }
 
 static bool isSentinel(const DWARFDebugNames::Abbrev &Abbr) {
@@ -505,7 +505,7 @@ DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getEmptyKey() {
 }
 
 DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getTombstoneKey() {
-  return DWARFDebugNames::Abbrev(~0, dwarf::Tag(0), {});
+  return DWARFDebugNames::Abbrev(~0, dwarf::Tag(0), 0, {});
 }
 
 Expected<DWARFDebugNames::AttributeEncoding>
@@ -540,7 +540,7 @@ DWARFDebugNames::NameIndex::extractAbbrev(uint64_t *Offset) {
     return createStringError(errc::illegal_byte_sequence,
                              "Incorrectly terminated abbreviation table.");
   }
-
+  const uint64_t AbbrevOffset = *Offset;
   uint32_t Code = Section.AccelSection.getULEB128(Offset);
   if (Code == 0)
     return sentinelAbbrev();
@@ -549,7 +549,7 @@ DWARFDebugNames::NameIndex::extractAbbrev(uint64_t *Offset) {
   auto AttrEncOr = extractAttributeEncodings(Offset);
   if (!AttrEncOr)
     return AttrEncOr.takeError();
-  return Abbrev(Code, dwarf::Tag(Tag), std::move(*AttrEncOr));
+  return Abbrev(Code, dwarf::Tag(Tag), AbbrevOffset, std::move(*AttrEncOr));
 }
 
 Error DWARFDebugNames::NameIndex::extract() {
@@ -847,8 +847,14 @@ void DWARFDebugNames::NameIndex::dumpForeignTUs(ScopedPrinter &W) const {
 
 void DWARFDebugNames::NameIndex::dumpAbbreviations(ScopedPrinter &W) const {
   ListScope AbbrevsScope(W, "Abbreviations");
-  for (const auto &Abbr : Abbrevs)
-    Abbr.dump(W);
+  std::vector<const Abbrev *> AbbrevsVect;
+  for (const DWARFDebugNames::Abbrev &Abbr : Abbrevs)
+    AbbrevsVect.push_back(&Abbr);
+  llvm::sort(AbbrevsVect, [](const Abbrev *LHS, const Abbrev *RHS) {
+    return LHS->AbbrevOffset < RHS->AbbrevOffset;
+  });
+  for (const DWARFDebugNames::Abbrev *Abbr : AbbrevsVect)
+    Abbr->dump(W);
 }
 
 void DWARFDebugNames::NameIndex::dumpBucket(ScopedPrinter &W,