[BOLT][DWARF] Remove patchLowHigh unused function.

[ayermolo]

Summary

Cleanup after removing caching mechanims for ranges/abbrevs.

[rafauler]

LGTM

bolt/include/bolt/Rewrite/DWARFRewriter.h

class DWARFRewriter {
 
   /// Update \p DIE that was using DW_AT_(low|high)_pc with DW_AT_ranges offset.
   /// Updates to the DIE should be synced with abbreviation updates using the
   /// function above.
   void convertToRangesPatchDebugInfo(DWARFDie DIE, uint64_t RangesSectionOffset,
                                      SimpleBinaryPatcher &DebugInfoPatcher,
                                      Optional<uint64_t> RangesBase = None);
 
-  /// Patch DW_AT_(low|high)_pc values for the \p DIE based on \p Range.
-  void patchLowHigh(DWARFDie DIE, DebugAddressRange Range,
-                    SimpleBinaryPatcher &DebugInfoPatcher,
-                    Optional<uint64_t> DWOId);
-
   /// Helper function for creating and returning per-DWO patchers/writers.
   template <class T, class Patcher>
   Patcher *getBinaryDWOPatcherHelper(T &BinaryPatchers, uint64_t DwoId) {
     std::lock_guard<std::mutex> Lock(DebugInfoPatcherMutex);
     auto Iter = BinaryPatchers.find(DwoId);
     if (Iter == BinaryPatchers.end()) {
       // Using make_pair instead of {} to work around bug in older version of
       // the library. https://timsong-cpp.github.io/lwg-issues/2354

bolt/lib/Rewrite/DWARFRewriter.cpp

errs() << "BOLT-WARNING: high_pc expected immediately after low_pc. "
            << "Cannot update DIE at offset 0x"
            << Twine::utohexstr(DIE.getOffset()) << '\n';
     return;
   }
 }
 
 } // namespace
 
-void DWARFRewriter::patchLowHigh(DWARFDie DIE, DebugAddressRange Range,
-                                 SimpleBinaryPatcher &DebugInfoPatcher,
-                                 Optional<uint64_t> DWOId) {
-  Optional<AttrInfo> LowPCVal = None;
-  Optional<AttrInfo> HighPCVal = None;
-  getRangeAttrData(DIE, LowPCVal, HighPCVal);
-  uint64_t LowPCOffset = LowPCVal->Offset;
-  uint64_t HighPCOffset = HighPCVal->Offset;
-  auto *TempDebugPatcher = &DebugInfoPatcher;
-  if (LowPCVal->V.getForm() == dwarf::DW_FORM_GNU_addr_index) {
-    uint32_t AddressIndex =
-        AddrWriter->getIndexFromAddress(Range.LowPC, *DWOId);
-    TempDebugPatcher = getBinaryDWODebugInfoPatcher(*DWOId);
-    TempDebugPatcher->addUDataPatch(LowPCOffset, AddressIndex, LowPCVal->Size);
-    // 2.17.2
-    // If the value of the DW_AT_high_pc is of class address, it is the
-    // relocated address of the first location past the last instruction
-    // associated with the entity; if it is of class constant, the value is
-    // an unsigned integer offset which when added to the low PC gives the
-    // address of the first location past the last instruction associated
-    // with the entity.
-    if (!HighPCVal->V.isFormClass(DWARFFormValue::FC_Constant)) {
-      AddressIndex = AddrWriter->getIndexFromAddress(Range.HighPC, *DWOId);
-      TempDebugPatcher->addUDataPatch(HighPCOffset, AddressIndex,
-                                      HighPCVal->Size);
-    }
-  } else {
-    TempDebugPatcher->addLE64Patch(LowPCOffset, Range.LowPC);
-  }
-
-  uint64_t HighPC = Range.HighPC;
-  // The DW_FORM_data* is delta between high and low pc
-  if (HighPCVal->V.getForm() != dwarf::Form::DW_FORM_addr)
-    HighPC -= Range.LowPC;
-
-  if (isHighPcFormEightBytes(HighPCVal->V.getForm()))
-    TempDebugPatcher->addLE64Patch(HighPCOffset, HighPC);
-  else
-    TempDebugPatcher->addLE32Patch(HighPCOffset, HighPC);
-}
-
 void DWARFRewriter::convertToRangesPatchAbbrev(
     const DWARFUnit &Unit, const DWARFAbbreviationDeclaration *Abbrev,
     DebugAbbrevWriter &AbbrevWriter, Optional<uint64_t> RangesBase) {
   auto getAttributeForm = [&Abbrev](const dwarf::Attribute Attr) {
     Optional<uint32_t> Index = Abbrev->findAttributeIndex(Attr);
     assert(Index && "attribute not found");
     return Abbrev->getFormByIndex(*Index);
   };