Completely rewrite ELFObjectWriter::RecordRelocation.

I started trying to fix a small issue, but this code has seen a small fix too
many.

The old code was fairly convoluted. Some of the issues it had:

* It failed to check if a symbol difference was in the some section when
  converting a relocation to pcrel.
* It failed to check if the relocation was already pcrel.
* The pcrel value computation was wrong in some cases (relocation-pc.s)
* It was missing quiet a few cases where it should not convert symbol
  relocations to section relocations, leaving the backends to patch it up.
* It would not propagate the fact that it had changed a relocation to pcrel,
  requiring a quiet nasty work around in ARM.
* It was missing comments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205076 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 9 insertions, 36 deletions

diff --git a/include/llvm/MC/MCAsmBackend.h b/include/llvm/MC/MCAsmBackend.h
index c5f6a66209..82b65fdaf5 100644
--- a/include/llvm/MC/MCAsmBackend.h
+++ b/include/llvm/MC/MCAsmBackend.h
@@ -97,7 +97,7 @@ public:
   /// data fragment, at the offset specified by the fixup and following the
   /// fixup kind as appropriate.
   virtual void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
-                          uint64_t Value) const = 0;
+                          uint64_t Value, bool IsPCRel) const = 0;
 
   /// @}
 
diff --git a/include/llvm/MC/MCAssembler.h b/include/llvm/MC/MCAssembler.h
index 506e555e48..6cb6fd232a 100644
--- a/include/llvm/MC/MCAssembler.h
+++ b/include/llvm/MC/MCAssembler.h
@@ -979,8 +979,8 @@ private:
   /// finishLayout - Finalize a layout, including fragment lowering.
   void finishLayout(MCAsmLayout &Layout);
 
-  uint64_t handleFixup(const MCAsmLayout &Layout,
-                       MCFragment &F, const MCFixup &Fixup);
+  std::pair<uint64_t, bool> handleFixup(const MCAsmLayout &Layout,
+                                        MCFragment &F, const MCFixup &Fixup);
 
 public:
   /// Compute the effective fragment size assuming it is laid out at the given
diff --git a/include/llvm/MC/MCELFObjectWriter.h b/include/llvm/MC/MCELFObjectWriter.h
index 78435e6f47..127f162487 100644
--- a/include/llvm/MC/MCELFObjectWriter.h
+++ b/include/llvm/MC/MCELFObjectWriter.h
@@ -20,30 +20,10 @@ class MCAssembler;
 class MCFixup;
 class MCFragment;
 class MCObjectWriter;
+class MCSectionData;
 class MCSymbol;
 class MCValue;
 
-/// @name Relocation Data
-/// @{
-
-struct ELFRelocationEntry {
-  // Make these big enough for both 32-bit and 64-bit
-  uint64_t r_offset;
-  int Index;
-  unsigned Type;
-  const MCSymbol *Symbol;
-  uint64_t r_addend;
-  const MCFixup *Fixup;
-
-  ELFRelocationEntry()
-    : r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0), Fixup(0) {}
-
-  ELFRelocationEntry(uint64_t RelocOffset, int Idx, unsigned RelType,
-                     const MCSymbol *Sym, uint64_t Addend, const MCFixup &Fixup)
-    : r_offset(RelocOffset), Index(Idx), Type(RelType), Symbol(Sym),
-      r_addend(Addend), Fixup(&Fixup) {}
-};
-
 class MCELFObjectTargetWriter {
   const uint8_t OSABI;
   const uint16_t EMachine;
@@ -73,17 +53,8 @@ public:
 
   virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
                                 bool IsPCRel) const = 0;
-  virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
-                                         const MCValue &Target,
-                                         const MCFragment &F,
-                                         const MCFixup &Fixup,
-                                         bool IsPCRel) const;
-  virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target,
-                                                  const MCFixup &Fixup,
-                                                  bool IsPCRel) const;
-
-  virtual void sortRelocs(const MCAssembler &Asm,
-                          std::vector<ELFRelocationEntry> &Relocs);
+
+  virtual bool needsRelocateWithSymbol(unsigned Type) const;
 
   /// @name Accessors
   /// @{
diff --git a/include/llvm/MC/MCMachObjectWriter.h b/include/llvm/MC/MCMachObjectWriter.h
index 644b44ecee..e7d5bbd5be 100644
--- a/include/llvm/MC/MCMachObjectWriter.h
+++ b/include/llvm/MC/MCMachObjectWriter.h
@@ -230,7 +230,8 @@ public:
 
   void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
                         const MCFragment *Fragment, const MCFixup &Fixup,
-                        MCValue Target, uint64_t &FixedValue) override;
+                        MCValue Target, bool &IsPCRel,
+                        uint64_t &FixedValue) override;
 
   void BindIndirectSymbols(MCAssembler &Asm);
 
diff --git a/include/llvm/MC/MCObjectWriter.h b/include/llvm/MC/MCObjectWriter.h
index 4939a3f1fb..55c828c6c1 100644
--- a/include/llvm/MC/MCObjectWriter.h
+++ b/include/llvm/MC/MCObjectWriter.h
@@ -80,6 +80,7 @@ public:
                                 const MCAsmLayout &Layout,
                                 const MCFragment *Fragment,
                                 const MCFixup &Fixup, MCValue Target,
+                                bool &IsPCRel,
                                 uint64_t &FixedValue) = 0;
 
   /// \brief Check whether the difference (A - B) between two symbol