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

[Sayhaan Siddiqui via llvm-commits]

https://github.com/sayhaan updated https://github.com/llvm/llvm-project/pull/97841

>From 6f0dfe61e43a62a4727f679b3e33232d223215d8 Mon Sep 17 00:00:00 2001
From: Sayhaan Siddiqui <sayhaan at meta.com>
Date: Fri, 28 Jun 2024 12:10:33 -0700
Subject: [PATCH 1/2] Remove unnecessary SectionOffset

Summary:

Test Plan:

Reviewers:

Subscribers:

Tasks:

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Differential Revision: https://phabricator.intern.facebook.com/D59175270
---
 bolt/include/bolt/Core/DebugData.h |  4 ----
 bolt/lib/Core/DebugData.cpp        | 15 +++++++++------
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/bolt/include/bolt/Core/DebugData.h b/bolt/include/bolt/Core/DebugData.h
index 144433ac78a37..cdcc8cd61f4fa 100644
--- a/bolt/include/bolt/Core/DebugData.h
+++ b/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};
 
diff --git a/bolt/lib/Core/DebugData.cpp b/bolt/lib/Core/DebugData.cpp
index 08d4c45aac791..dbf36ea3328a4 100644
--- a/bolt/lib/Core/DebugData.cpp
+++ b/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;
 }
 
@@ -166,15 +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;
 }
 
 void DebugRangesSectionWriter::appendToRangeBuffer(
@@ -327,7 +331,6 @@ void DebugRangeListsSectionWriter::finalizeSection() {
   *RangesStream << *Header;
   *RangesStream << *CUArrayBuffer;
   *RangesStream << *CUBodyBuffer;
-  SectionOffset = RangesBuffer->size();
 }
 
 void DebugRangeListsSectionWriter::initSection(DWARFUnit &Unit) {

>From c436409d51efbacc7720222763665955323e0092 Mon Sep 17 00:00:00 2001
From: Sayhaan Siddiqui <sayhaan at meta.com>
Date: Fri, 5 Jul 2024 10:55:05 -0700
Subject: [PATCH 2/2] Fix duplicated function

---
 bolt/lib/Core/DebugData.cpp | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/bolt/lib/Core/DebugData.cpp b/bolt/lib/Core/DebugData.cpp
index dbf36ea3328a4..579af3bce4eb8 100644
--- a/bolt/lib/Core/DebugData.cpp
+++ b/bolt/lib/Core/DebugData.cpp
@@ -181,12 +181,6 @@ void DebugRangesSectionWriter::appendToRangeBuffer(
   *RangesStream << CUBuffer;
 }
 
-void DebugRangesSectionWriter::appendToRangeBuffer(
-    const DebugBufferVector &CUBuffer) {
-  *RangesStream << CUBuffer;
-  SectionOffset = RangesBuffer->size();
-}
-
 DebugAddrWriter *DebugRangeListsSectionWriter::AddrWriter = nullptr;
 
 uint64_t DebugRangeListsSectionWriter::addRanges(