[BOLT][DWARF][NFC] Fix DebugStrOffsetsWriter so updateAddressMap can't be called after it is finalized

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Differential Revision: https://phabricator.intern.facebook.com/D60293063

Author: sayhaan

bolt/include/bolt/Core/DebugData.h

@@ -503,10 +503,15 @@ class DebugStrOffsetsWriter {
     return StrOffsetSectionWasModified;
   }
 
+  std::unordered_map<uint64_t, bool> &getDebugStrOffsetFinalized() {
+    return DebugStrOffsetFinalized;
+  }
+
 private:
   std::unique_ptr<DebugStrOffsetsBufferVector> StrOffsetsBuffer;
   std::unique_ptr<raw_svector_ostream> StrOffsetsStream;
   std::map<uint32_t, uint32_t> IndexToAddressMap;
+  std::unordered_map<uint64_t, bool> DebugStrOffsetFinalized;
   SmallVector<uint32_t, 5> StrOffsets;
   std::unordered_map<uint64_t, uint64_t> ProcessedBaseOffsets;
   bool StrOffsetSectionWasModified = false;

bolt/lib/Core/DIEBuilder.cpp

@@ -77,6 +77,9 @@ static void addStringHelper(DebugStrOffsetsWriter &StrOffstsWriter,
                             DIEValue &DIEAttrInfo, StringRef Str) {
   uint32_t NewOffset = StrWriter.addString(Str);
   if (Unit.getVersion() >= 5) {
+    assert(StrOffstsWriter.getDebugStrOffsetFinalized().count(
+               Unit.getOffset()) == 0 &&
+           "debug_str_offsets was already finalized.");
     StrOffstsWriter.updateAddressMap(DIEAttrInfo.getDIEInteger().getValue(),
                                      NewOffset);
     return;

bolt/lib/Core/DebugData.cpp

@@ -906,6 +906,7 @@ void DebugStrOffsetsWriter::finalizeSection(DWARFUnit &Unit,
   }
 
   StrOffsetSectionWasModified = false;
+  DebugStrOffsetFinalized[Unit.getOffset()] = true;
   clear();
 }
 

bolt/lib/Rewrite/DWARFRewriter.cpp

@@ -757,6 +757,8 @@ void DWARFRewriter::updateDebugInfo() {
               : std::optional<std::string>(opts::DwarfOutputPath.c_str());
       std::string DWOName = DIEBlder.updateDWONameCompDir(
           *StrOffstsWriter, *StrWriter, *CU, DwarfOutputPath, std::nullopt);
+      if (CU->getVersion() >= 5)
+        StrOffstsWriter->finalizeSection(*CU, DIEBlder);
       processSplitCU(*CU, **SplitCU, DIEBlder, *TempRangesSectionWriter,
                      AddressWriter, DWOName, DwarfOutputPath);
     }

bolt/test/X86/dwarf5-df-input-lowpc-ranges-cus.test

@@ -6,7 +6,7 @@
 ; RUN: llvm-mc -dwarf-version=5 -filetype=obj -triple x86_64-unknown-linux %p/Inputs/dwarf5-df-input-lowpc-ranges-other.s \
 ; RUN: -split-dwarf-file=mainOther.dwo -o other.o
 ; RUN: %clang %cflags main.o other.o -o main.exe
-; RUN: llvm-bolt main.exe -o main.exe.bolt --update-debug-sections
+; RUN: llvm-bolt main.exe -o main.exe.bolt --update-debug-sections --cu-processing-batch-size=2
 ; RUN: llvm-dwarfdump --show-form --verbose --debug-rnglists main.exe.bolt &> %t/foo.txt
 ; RUN: llvm-dwarfdump --show-form --verbose --debug-addr main.exe.bolt >> %t/foo.txt
 ; RUN: llvm-dwarfdump --show-form --verbose --debug-info main.exe.bolt >> %t/foo.txt