Consider the modified str and offsets in the buffer.

Author: Sockke

bolt/include/bolt/Core/DebugData.h

@@ -471,6 +471,11 @@ class DebugStrOffsetsWriter {
     return std::move(StrOffsetsBuffer);
   }
 
+  StringRef bufferStr() {
+    return StringRef(reinterpret_cast<const char *>(StrOffsetsBuffer->data()),
+                     StrOffsetsBuffer->size());
+  }
+
   /// Initializes Buffer and Stream.
   void initialize(DWARFUnit &Unit);
 
@@ -507,6 +512,11 @@ class DebugStrWriter {
     return std::move(StrBuffer);
   }
 
+  StringRef bufferStr() {
+    return StringRef(reinterpret_cast<const char *>(StrBuffer->data()),
+                     StrBuffer->size());
+  }
+
   /// Adds string to .debug_str.
   /// On first invocation it initializes internal data structures.
   uint32_t addString(StringRef Str);

bolt/lib/Rewrite/DWARFRewriter.cpp

@@ -1831,6 +1831,8 @@ std::optional<StringRef> updateDebugData(
       errs() << "BOLT-WARNING: unsupported debug section: " << SectionName
              << "\n";
     if (StrWriter.isInitialized()) {
+      if (CUDWOEntry)
+        return StrWriter.bufferStr();
       OutputBuffer = StrWriter.releaseBuffer();
       return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
                        OutputBuffer->size());
@@ -1845,6 +1847,8 @@ std::optional<StringRef> updateDebugData(
   }
   case DWARFSectionKind::DW_SECT_STR_OFFSETS: {
     if (StrOffstsWriter.isFinalized()) {
+      if (CUDWOEntry)
+        return StrOffstsWriter.bufferStr();
       OutputBuffer = StrOffstsWriter.releaseBuffer();
       return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
                        OutputBuffer->size());
@@ -1959,7 +1963,10 @@ void DWARFRewriter::writeDWOFiles(
     Expected<StringRef> ContentsExp = Section.getContents();
     assert(ContentsExp && "Invalid contents.");
     if (IsDWP && SectionName == "debug_str.dwo") {
-      StrDWOContent = *ContentsExp;
+      if (StrWriter.isInitialized())
+        StrDWOContent = StrWriter.bufferStr();
+      else
+        StrDWOContent = *ContentsExp;
       continue;
     }
     if (std::optional<StringRef> OutData = updateDebugData(