[ExecutionEngine] Remove unused function addCustomSectionParser

[kazu]

Summary

The last use was removed by:

commit 76aee8a389447409905c58b178b0554c9bae8a0a
Author: Lang Hames <[e-mail]>
Date:   Mon Nov 4 16:00:09 2019 -0800

Once I remove addCustomSectionParser, nobody adds anything to
CustomSectionParserFunctions, so this patch removes all the code
having to do with CustomSectionParserFunctions.

[lhames]

I need to have a think about this one -- these were placeholders and we might benefit from refactoring the current code to use them.

llvm/lib/ExecutionEngine/JITLink/MachOLinkGraphBuilder.h

protected:
   MachOLinkGraphBuilder(const object::MachOObjectFile &Obj, Triple TT,
                         LinkGraph::FeatureVector Features,
                         LinkGraph::GetEdgeKindNameFunction GetEdgeKindName);
 
   LinkGraph &getGraph() const { return *G; }
 
   const object::MachOObjectFile &getObject() const { return Obj; }
 
-  void addCustomSectionParser(StringRef SectionName,
-                              SectionParserFunction Parse);
-
   virtual Error addRelocations() = 0;
 
   /// Create a symbol.
   template <typename... ArgTs>
   NormalizedSymbol &createNormalizedSymbol(ArgTs &&... Args) {
     NormalizedSymbol *Sym = reinterpret_cast<NormalizedSymbol *>(
         Allocator.Allocate<NormalizedSymbol>());
     new (Sym) NormalizedSymbol(std::forward<ArgTs>(Args)...);
private:
   /// Create and return a graph symbol for the given normalized symbol.
   ///
   /// NSym's GraphSymbol member will be updated to point at the newly created
   /// symbol.
   Symbol &createStandardGraphSymbol(NormalizedSymbol &Sym, Block &B,
                                     size_t Size, bool IsText,
                                     bool IsNoDeadStrip, bool IsCanonical);
 
-  /// Create graph blocks and symbols for all sections.
-  Error graphifySectionsWithCustomParsers();
-
   /// Graphify cstring section.
   Error graphifyCStringSection(NormalizedSection &NSec,
                                std::vector<NormalizedSymbol *> NSyms);
 
   // Put the BumpPtrAllocator first so that we don't free any of the underlying
   // memory until the Symbol/Addressable destructors have been run.
   BumpPtrAllocator Allocator;
 
   const object::MachOObjectFile &Obj;
   std::unique_ptr<LinkGraph> G;
 
   bool SubsectionsViaSymbols = false;
   DenseMap<unsigned, NormalizedSection> IndexToSection;
   Section *CommonSection = nullptr;
 
   DenseMap<uint32_t, NormalizedSymbol *> IndexToSymbol;
-  StringMap<SectionParserFunction> CustomSectionParserFunctions;
 };
 
 /// A pass to split up __LD,__compact_unwind sections.
 class CompactUnwindSplitter {
 public:
   CompactUnwindSplitter(StringRef CompactUnwindSectionName)
       : CompactUnwindSectionName(CompactUnwindSectionName) {}
   Error operator()(LinkGraph &G);

llvm/lib/ExecutionEngine/JITLink/MachOLinkGraphBuilder.cpp

if (auto Err = createNormalizedSections())
     return std::move(Err);
 
   if (auto Err = createNormalizedSymbols())
     return std::move(Err);
 
   if (auto Err = graphifyRegularSymbols())
     return std::move(Err);
 
-  if (auto Err = graphifySectionsWithCustomParsers())
-    return std::move(Err);
-
   if (auto Err = addRelocations())
     return std::move(Err);
 
   return std::move(G);
 }
 
 MachOLinkGraphBuilder::MachOLinkGraphBuilder(
     const object::MachOObjectFile &Obj, Triple TT,
     LinkGraph::FeatureVector Features,
     LinkGraph::GetEdgeKindNameFunction GetEdgeKindName)
     : Obj(Obj),
       G(std::make_unique<LinkGraph>(std::string(Obj.getFileName()),
                                     std::move(TT), std::move(Features),
                                     getPointerSize(Obj), getEndianness(Obj),
                                     std::move(GetEdgeKindName))) {
   auto &MachHeader = Obj.getHeader64();
   SubsectionsViaSymbols = MachHeader.flags & MachO::MH_SUBSECTIONS_VIA_SYMBOLS;
 }
 
-void MachOLinkGraphBuilder::addCustomSectionParser(
-    StringRef SectionName, SectionParserFunction Parser) {
-  assert(!CustomSectionParserFunctions.count(SectionName) &&
-         "Custom parser for this section already exists");
-  CustomSectionParserFunctions[SectionName] = std::move(Parser);
-}
-
 Linkage MachOLinkGraphBuilder::getLinkage(uint16_t Desc) {
   if ((Desc & MachO::N_WEAK_DEF) || (Desc & MachO::N_WEAK_REF))
     return Linkage::Weak;
   return Linkage::Strong;
 }
 
 Scope MachOLinkGraphBuilder::getScope(StringRef Name, uint8_t Type) {
   if (Type & MachO::N_EXT) {
for (auto &KV : IndexToSection) {
     if (!NSec.GraphSection) {
       LLVM_DEBUG({
         dbgs() << "  " << NSec.SegName << "/" << NSec.SectName
                << " has no graph section. Skipping.\n";
       });
       continue;
     }
 
-    // Skip sections with custom parsers.
-    if (CustomSectionParserFunctions.count(NSec.GraphSection->getName())) {
-      LLVM_DEBUG({
-        dbgs() << "  Skipping section " << NSec.GraphSection->getName()
-               << " as it has a custom parser.\n";
-      });
-      continue;
-    } else if ((NSec.Flags & MachO::SECTION_TYPE) ==
+    if ((NSec.Flags & MachO::SECTION_TYPE) ==
                MachO::S_CSTRING_LITERALS) {
       if (auto Err = graphifyCStringSection(
               NSec, std::move(SecIndexToSymbols[SecIndex])))
         return Err;
       continue;
     } else
       LLVM_DEBUG({
         dbgs() << "  Graphifying regular section "
Symbol &MachOLinkGraphBuilder::createStandardGraphSymbol(NormalizedSymbol &NSym,
   NSym.GraphSymbol = &Sym;
 
   if (IsCanonical)
     setCanonicalSymbol(getSectionByIndex(NSym.Sect - 1), Sym);
 
   return Sym;
 }
 
-Error MachOLinkGraphBuilder::graphifySectionsWithCustomParsers() {
-  // Graphify special sections.
-  for (auto &KV : IndexToSection) {
-    auto &NSec = KV.second;
-
-    // Skip non-graph sections.
-    if (!NSec.GraphSection)
-      continue;
-
-    auto HI = CustomSectionParserFunctions.find(NSec.GraphSection->getName());
-    if (HI != CustomSectionParserFunctions.end()) {
-      auto &Parse = HI->second;
-      if (auto Err = Parse(NSec))
-        return Err;
-    }
-  }
-
-  return Error::success();
-}
-
 Error MachOLinkGraphBuilder::graphifyCStringSection(
     NormalizedSection &NSec, std::vector<NormalizedSymbol *> NSyms) {
   assert(NSec.GraphSection && "C string literal section missing graph section");
   assert(NSec.Data && "C string literal section has no data");
 
   LLVM_DEBUG({
     dbgs() << "  Graphifying C-string literal section "
            << NSec.GraphSection->getName() << "\n";