[PATCH] D14993: [ELF] - simplify Target interface, relocPointsToGot() removed.

[George Rimar via llvm-commits]

grimar created this revision.
grimar added reviewers: ruiu, rafael.
grimar added subscribers: grimar, llvm-commits.

relocPointsToGot() is used only for x86. I think we can remove it and move calculation to i386 code.

Description (https://docs.oracle.com/cd/E19683-01/817-3677/chapter6-26/index.html) says:
R_386_GOTPC
Resembles R_386_PC32, except that it uses the address of the global offset table in its calculation. The symbol referenced in this relocation normally is _GLOBAL_OFFSET_TABLE_, which also instructs the link-editor to create the global offset table.

Currently _GLOBAL_OFFSET_TABLE_ has value == zero. And we use GOT address to calculate the relocation. This patch does not changes that. It just removes the method which is used only for x86. So it is close to non functional change.

http://reviews.llvm.org/D14993

Files:
  ELF/InputSection.cpp
  ELF/Target.cpp
  ELF/Target.h

Index: ELF/Target.h
===================================================================
--- ELF/Target.h
+++ ELF/Target.h
@@ -24,7 +24,6 @@
   unsigned getPageSize() const { return PageSize; }
   uint64_t getVAStart() const;
   unsigned getCopyReloc() const { return CopyReloc; }
-  unsigned getPCRelReloc() const { return PCRelReloc; }
   unsigned getGotReloc() const { return GotReloc; }
   unsigned getPltReloc() const { return PltReloc; }
   unsigned getRelativeReloc() const { return RelativeReloc; }
@@ -55,7 +54,6 @@
   virtual bool isRelRelative(uint32_t Type) const;
   virtual bool relocNeedsCopy(uint32_t Type, const SymbolBody &S) const;
   virtual bool relocNeedsGot(uint32_t Type, const SymbolBody &S) const = 0;
-  virtual bool relocPointsToGot(uint32_t Type) const;
   virtual bool relocNeedsPlt(uint32_t Type, const SymbolBody &S) const = 0;
   virtual void relocateOne(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
                            uint64_t P, uint64_t SA) const = 0;
Index: ELF/Target.cpp
===================================================================
--- ELF/Target.cpp
+++ ELF/Target.cpp
@@ -53,7 +53,6 @@
                      uint64_t PltEntryAddr, int32_t Index) const override;
   bool relocNeedsCopy(uint32_t Type, const SymbolBody &S) const override;
   bool relocNeedsGot(uint32_t Type, const SymbolBody &S) const override;
-  bool relocPointsToGot(uint32_t Type) const override;
   bool relocNeedsPlt(uint32_t Type, const SymbolBody &S) const override;
   void relocateOne(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type, uint64_t P,
                    uint64_t SA) const override;
@@ -166,8 +165,6 @@
 
 unsigned TargetInfo::getPltRefReloc(unsigned Type) const { return PCRelReloc; }
 
-bool TargetInfo::relocPointsToGot(uint32_t Type) const { return false; }
-
 bool TargetInfo::isRelRelative(uint32_t Type) const { return true; }
 
 void TargetInfo::relocateTlsOptimize(uint8_t *Loc, uint8_t *BufEnd, uint64_t P,
@@ -209,10 +206,6 @@
   return Type == R_386_GOT32 || relocNeedsPlt(Type, S);
 }
 
-bool X86TargetInfo::relocPointsToGot(uint32_t Type) const {
-  return Type == R_386_GOTPC;
-}
-
 bool X86TargetInfo::relocNeedsPlt(uint32_t Type, const SymbolBody &S) const {
   return Type == R_386_PLT32 || (Type == R_386_PC32 && S.isShared());
 }
@@ -223,6 +216,9 @@
   case R_386_GOT32:
     add32le(Loc, SA - Out<ELF32LE>::Got->getVA());
     break;
+  case R_386_GOTPC:
+    add32le(Loc, SA + Out<ELF32LE>::Got->getVA() - P);
+    break;
   case R_386_PC32:
     add32le(Loc, SA - P);
     break;
Index: ELF/InputSection.cpp
===================================================================
--- ELF/InputSection.cpp
+++ ELF/InputSection.cpp
@@ -148,9 +148,6 @@
       SymVA = Out<ELFT>::Got->getEntryAddr(Body);
       Type = Body.isTLS() ? Target->getTlsGotReloc()
                           : Target->getGotRefReloc(Type);
-    } else if (Target->relocPointsToGot(Type)) {
-      SymVA = Out<ELFT>::Got->getVA();
-      Type = Target->getPCRelReloc();
     } else if (!Target->relocNeedsCopy(Type, Body) &&
                isa<SharedSymbol<ELFT>>(Body)) {
       continue;


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