[DebugInfo][NFC] Use function_ref consistently in debug line parsing

[jhenderson]

Summary

This patch fixes an inconsistency where we were using std::function in some places and function_ref in others to pass around the error handling callback.

[MaskRay]

llvm::function_ref is more common and more efficient (std::function has a heap allocation). These callbacks are not supposed to be stored. LG

llvm/include/llvm/DebugInfo/DWARF/DWARFContext.h

public:
   /// Get a pointer to a parsed line table corresponding to a compile unit.
   /// Report any parsing issues as warnings on stderr.
   const DWARFDebugLine::LineTable *getLineTableForUnit(DWARFUnit *U);
 
   /// Get a pointer to a parsed line table corresponding to a compile unit.
   /// Report any recoverable parsing problems using the callback.
   Expected<const DWARFDebugLine::LineTable *>
   getLineTableForUnit(DWARFUnit *U,
-                      std::function<void(Error)> RecoverableErrorCallback);
+                      function_ref<void(Error)> RecoverableErrorCallback);
 
   DataExtractor getStringExtractor() const {
     return DataExtractor(DObj->getStrSection(), false, 0);
   }
   DataExtractor getLineStringExtractor() const {
     return DataExtractor(DObj->getLineStrSection(), false, 0);
   }
 

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h

bool getFileLineInfoForAddress(object::SectionedAddress Address,
                                    const char *CompDir,
                                    DILineInfoSpecifier::FileLineInfoKind Kind,
                                    DILineInfo &Result) const;
 
     void dump(raw_ostream &OS, DIDumpOptions DumpOptions) const;
     void clear();
 
     /// Parse prologue and all rows.
-    Error parse(
-        DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
+    Error parse(DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
                 const DWARFContext &Ctx, const DWARFUnit *U,
-        std::function<void(Error)> RecoverableErrorCallback,
+                function_ref<void(Error)> RecoverableErrorCallback,
                 raw_ostream *OS = nullptr);
 
     using RowVector = std::vector<Row>;
     using RowIter = RowVector::const_iterator;
     using SequenceVector = std::vector<Sequence>;
     using SequenceIter = SequenceVector::const_iterator;
 
     struct Prologue Prologue;
     RowVector Rows;
     SequenceVector Sequences;
 
   private:
     uint32_t findRowInSeq(const DWARFDebugLine::Sequence &Seq,
                           object::SectionedAddress Address) const;
     Optional<StringRef>
     getSourceByIndex(uint64_t FileIndex,
                      DILineInfoSpecifier::FileLineInfoKind Kind) const;
 
     uint32_t lookupAddressImpl(object::SectionedAddress Address) const;
 
     bool lookupAddressRangeImpl(object::SectionedAddress Address, uint64_t Size,
                                 std::vector<uint32_t> &Result) const;
   };
 
   const LineTable *getLineTable(uint64_t Offset) const;
-  Expected<const LineTable *> getOrParseLineTable(
-      DWARFDataExtractor &DebugLineData, uint64_t Offset,
+  Expected<const LineTable *>
+  getOrParseLineTable(DWARFDataExtractor &DebugLineData, uint64_t Offset,
                       const DWARFContext &Ctx, const DWARFUnit *U,
-      std::function<void(Error)> RecoverableErrorCallback);
+                      function_ref<void(Error)> RecoverableErrorCallback);
 
   /// Helper to allow for parsing of an entire .debug_line section in sequence.
   class SectionParser {
   public:
     using cu_range = DWARFUnitVector::iterator_range;
     using tu_range = DWARFUnitVector::iterator_range;
     using LineToUnitMap = std::map<uint64_t, DWARFUnit *>;
 

llvm/lib/DebugInfo/DWARF/DWARFContext.cpp

DWARFContext::getLineTableForUnit(DWARFUnit *U) {
   if (!ExpectedLineTable) {
     dumpWarning(ExpectedLineTable.takeError());
     return nullptr;
   }
   return *ExpectedLineTable;
 }
 
 Expected<const DWARFDebugLine::LineTable *> DWARFContext::getLineTableForUnit(
-    DWARFUnit *U, std::function<void(Error)> RecoverableErrorCallback) {
+    DWARFUnit *U, function_ref<void(Error)> RecoverableErrorCallback) {
   if (!Line)
     Line.reset(new DWARFDebugLine);
 
   auto UnitDIE = U->getUnitDIE();
   if (!UnitDIE)
     return nullptr;
 
   auto Offset = toSectionOffset(UnitDIE.find(DW_AT_stmt_list));

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

DWARFDebugLine::getLineTable(uint64_t Offset) const {
   LineTableConstIter Pos = LineTableMap.find(Offset);
   if (Pos != LineTableMap.end())
     return &Pos->second;
   return nullptr;
 }
 
 Expected<const DWARFDebugLine::LineTable *> DWARFDebugLine::getOrParseLineTable(
     DWARFDataExtractor &DebugLineData, uint64_t Offset, const DWARFContext &Ctx,
-    const DWARFUnit *U, std::function<void(Error)> RecoverableErrorCallback) {
+    const DWARFUnit *U, function_ref<void(Error)> RecoverableErrorCallback) {
   if (!DebugLineData.isValidOffset(Offset))
     return createStringError(errc::invalid_argument, "offset 0x%8.8" PRIx64
                        " is not a valid debug line section offset",
                        Offset);
 
   std::pair<LineTableIter, bool> Pos =
       LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
   LineTable *LT = &Pos.first->second;
   if (Pos.second) {
     if (Error Err =
             LT->parse(DebugLineData, &Offset, Ctx, U, RecoverableErrorCallback))
       return std::move(Err);
     return LT;
   }
   return LT;
 }
 
 Error DWARFDebugLine::LineTable::parse(
     DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
     const DWARFContext &Ctx, const DWARFUnit *U,
-    std::function<void(Error)> RecoverableErrorCallback, raw_ostream *OS) {
+    function_ref<void(Error)> RecoverableErrorCallback, raw_ostream *OS) {
   const uint64_t DebugLineOffset = *OffsetPtr;
 
   clear();
 
   Error PrologueErr = Prologue.parse(DebugLineData, OffsetPtr, Ctx, U);
 
   if (OS) {
     // The presence of OS signals verbose dumping.