Cleanup getRelocationAddend.

Realistically, this will be returning ErrorOr for some time as refactoring the
user code to check once per section will take some time.

Given that, use it for checking if a relocation has addend or not.

While at it, add ELFRelocationRef to simplify the users.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241028 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Object/ELFObjectFile.h

@@ -37,10 +37,12 @@ namespace object {
 
 class elf_symbol_iterator;
 class ELFSymbolRef;
+class ELFRelocationRef;
 
 class ELFObjectFileBase : public ObjectFile {
   friend class ELFSymbolRef;
   friend class ELFSectionRef;
+  friend class ELFRelocationRef;
 
 protected:
   ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source);
@@ -52,12 +54,8 @@ protected:
   virtual uint32_t getSectionType(DataRefImpl Sec) const = 0;
   virtual uint64_t getSectionFlags(DataRefImpl Sec) const = 0;
 
-public:
   virtual ErrorOr<int64_t> getRelocationAddend(DataRefImpl Rel) const = 0;
-
-  // FIXME: This is a bit of a hack. Every caller should know if it expecting
-  // and addend or not.
-  virtual bool hasRelocationAddend(DataRefImpl Rel) const = 0;
+public:
 
   typedef iterator_range<elf_symbol_iterator> elf_symbol_iterator_range;
   virtual elf_symbol_iterator_range getDynamicSymbolIterators() const = 0;
@@ -139,6 +137,38 @@ public:
   }
 };
 
+class ELFRelocationRef : public RelocationRef {
+public:
+  ELFRelocationRef(const RelocationRef &B) : RelocationRef(B) {
+    assert(isa<ELFObjectFileBase>(RelocationRef::getObject()));
+  }
+
+  const ELFObjectFileBase *getObject() const {
+    return cast<ELFObjectFileBase>(RelocationRef::getObject());
+  }
+
+  ErrorOr<int64_t> getAddend() const {
+    return getObject()->getRelocationAddend(getRawDataRefImpl());
+  }
+};
+
+class elf_relocation_iterator : public relocation_iterator {
+public:
+  elf_relocation_iterator(const relocation_iterator &B)
+      : relocation_iterator(RelocationRef(
+            B->getRawDataRefImpl(), cast<ELFObjectFileBase>(B->getObject()))) {}
+
+  const ELFRelocationRef *operator->() const {
+    return static_cast<const ELFRelocationRef *>(
+        relocation_iterator::operator->());
+  }
+
+  const ELFRelocationRef &operator*() const {
+    return static_cast<const ELFRelocationRef &>(
+        relocation_iterator::operator*());
+  }
+};
+
 inline ELFObjectFileBase::elf_symbol_iterator_range
 ELFObjectFileBase::symbols() const {
   return elf_symbol_iterator_range(symbol_begin(), symbol_end());
@@ -295,7 +325,6 @@ public:
   section_iterator section_end() const override;
 
   ErrorOr<int64_t> getRelocationAddend(DataRefImpl Rel) const override;
-  bool hasRelocationAddend(DataRefImpl Rel) const override;
 
   uint8_t getBytesInAddress() const override;
   StringRef getFileFormatName() const override;
@@ -733,11 +762,6 @@ ELFObjectFile<ELFT>::getRelocationAddend(DataRefImpl Rel) const {
   return (int64_t)getRela(Rel)->r_addend;
 }
 
-template <class ELFT>
-bool ELFObjectFile<ELFT>::hasRelocationAddend(DataRefImpl Rel) const {
-  return getRelSection(Rel)->sh_type == ELF::SHT_RELA;
-}
-
 template <class ELFT>
 const typename ELFFile<ELFT>::Elf_Sym *
 ELFObjectFile<ELFT>::getSymbol(DataRefImpl Symb) const {

include/llvm/Object/RelocVisitor.h

@@ -240,9 +240,7 @@ private:
   }
 
   int64_t getELFAddend(RelocationRef R) {
-    const auto *Obj = cast<ELFObjectFileBase>(R.getObject());
-    DataRefImpl DRI = R.getRawDataRefImpl();
-    ErrorOr<int64_t> AddendOrErr = Obj->getRelocationAddend(DRI);
+    ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(R).getAddend();
     if (std::error_code EC = AddendOrErr.getError())
       report_fatal_error(EC.message());
     return *AddendOrErr;

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

@@ -767,8 +767,8 @@ void RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
     if (RelSectionName != ".opd")
       continue;
 
-    for (relocation_iterator i = si->relocation_begin(),
-                             e = si->relocation_end();
+    for (elf_relocation_iterator i = si->relocation_begin(),
+                                 e = si->relocation_end();
          i != e;) {
       // The R_PPC64_ADDR64 relocation indicates the first field
       // of a .opd entry
@@ -781,8 +781,7 @@ void RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
 
       uint64_t TargetSymbolOffset = i->getOffset();
       symbol_iterator TargetSymbol = i->getSymbol();
-      ErrorOr<int64_t> AddendOrErr =
-          Obj.getRelocationAddend(i->getRawDataRefImpl());
+      ErrorOr<int64_t> AddendOrErr = i->getAddend();
       Check(AddendOrErr.getError());
       int64_t Addend = *AddendOrErr;
 
@@ -1062,9 +1061,8 @@ relocation_iterator RuntimeDyldELF::processRelocationRef(
   const auto &Obj = cast<ELFObjectFileBase>(O);
   uint64_t RelType;
   Check(RelI->getType(RelType));
-  int64_t Addend = 0;
-  if (Obj.hasRelocationAddend(RelI->getRawDataRefImpl()))
-    Addend = *Obj.getRelocationAddend(RelI->getRawDataRefImpl());
+  ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend();
+  int64_t Addend = AddendOrErr ? *AddendOrErr : 0;
   elf_symbol_iterator Symbol = RelI->getSymbol();
 
   // Obtain the symbol name which is referenced in the relocation

lib/Target/X86/MCTargetDesc/X86ELFRelocationInfo.cpp

@@ -31,9 +31,8 @@ public:
 
     StringRef SymName; SymI->getName(SymName);
     uint64_t  SymAddr; SymI->getAddress(SymAddr);
-    auto *Obj = cast<ELFObjectFileBase>(Rel.getObject());
     uint64_t SymSize = SymI->getSize();
-    int64_t Addend = *Obj->getRelocationAddend(Rel.getRawDataRefImpl());
+    int64_t Addend = *ELFRelocationRef(Rel).getAddend();
 
     MCSymbol *Sym = Ctx.getOrCreateSymbol(SymName);
     // FIXME: check that the value is actually the same.