[BOLT][DWARF][NFC] Remove unnecessary SectionOffset (llvm#97841)

Removes unnecessary SectionOffset variable from DebugData.

Author: sayhaan

bolt/include/bolt/Core/DebugData.h

@@ -233,10 +233,6 @@ class DebugRangesSectionWriter {
 
   std::mutex WriterMutex;
 
-  /// Current offset in the section (updated as new entries are written).
-  /// Starts with 16 since the first 16 bytes are reserved for an empty range.
-  uint32_t SectionOffset{0};
-
   /// Offset of an empty address ranges list.
   static constexpr uint64_t EmptyRangesOffset{0};
 

bolt/lib/Core/DebugData.cpp

@@ -138,8 +138,7 @@ DebugRangesSectionWriter::DebugRangesSectionWriter() {
   RangesStream = std::make_unique<raw_svector_ostream>(*RangesBuffer);
 
   // Add an empty range as the first entry;
-  SectionOffset +=
-      writeAddressRanges(*RangesStream.get(), DebugAddressRangesVector{});
+  writeAddressRanges(*RangesStream.get(), DebugAddressRangesVector{});
   Kind = RangesWriterKind::DebugRangesWriter;
 }
 
@@ -166,21 +165,20 @@ uint64_t DebugRangesSectionWriter::addRanges(DebugAddressRangesVector &Ranges) {
   // Reading the SectionOffset and updating it should be atomic to guarantee
   // unique and correct offsets in patches.
   std::lock_guard<std::mutex> Lock(WriterMutex);
-  const uint32_t EntryOffset = SectionOffset;
-  SectionOffset += writeAddressRanges(*RangesStream.get(), Ranges);
+  const uint32_t EntryOffset = RangesBuffer->size();
+  writeAddressRanges(*RangesStream.get(), Ranges);
 
   return EntryOffset;
 }
 
 uint64_t DebugRangesSectionWriter::getSectionOffset() {
   std::lock_guard<std::mutex> Lock(WriterMutex);
-  return SectionOffset;
+  return RangesBuffer->size();
 }
 
 void DebugRangesSectionWriter::appendToRangeBuffer(
     const DebugBufferVector &CUBuffer) {
   *RangesStream << CUBuffer;
-  SectionOffset = RangesBuffer->size();
 }
 
 DebugAddrWriter *DebugRangeListsSectionWriter::AddrWriter = nullptr;
@@ -327,7 +325,6 @@ void DebugRangeListsSectionWriter::finalizeSection() {
   *RangesStream << *Header;
   *RangesStream << *CUArrayBuffer;
   *RangesStream << *CUBodyBuffer;
-  SectionOffset = RangesBuffer->size();
 }
 
 void DebugRangeListsSectionWriter::initSection(DWARFUnit &Unit) {