[MC] Remove an overload of isSymbolRefDifferenceFullyResolvedImpl

e3a20f5 (2015) overloaded
isSymbolRefDifferenceFullyResolvedImpl with the IsPCRel parameter.
The overload without IsPCRel is only customized by Mach-O to
dsiable `.long L_var4 - L_var3` folding in
darwin-x86_64-diff-reloc-assign-2.s, but that seems unnecessary.

Author: MaskRay

llvm/include/llvm/MC/MCMachObjectWriter.h

@@ -254,11 +254,6 @@ class MachObjectWriter : public MCObjectWriter {
   void executePostLayoutBinding(MCAssembler &Asm,
                                 const MCAsmLayout &Layout) override;
 
-  bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
-                                              const MCSymbol &A,
-                                              const MCSymbol &B,
-                                              bool InSet) const override;
-
   bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
                                               const MCSymbol &SymA,
                                               const MCFragment &FB, bool InSet,

llvm/include/llvm/MC/MCObjectWriter.h

@@ -78,11 +78,6 @@ class MCObjectWriter {
                                           const MCSymbolRefExpr *B,
                                           bool InSet) const;
 
-  virtual bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
-                                                      const MCSymbol &A,
-                                                      const MCSymbol &B,
-                                                      bool InSet) const;
-
   virtual bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
                                                       const MCSymbol &SymA,
                                                       const MCFragment &FB,

llvm/lib/MC/MCObjectWriter.cpp

@@ -29,17 +29,11 @@ bool MCObjectWriter::isSymbolRefDifferenceFullyResolved(
   const MCSymbol &SA = A->getSymbol();
   const MCSymbol &SB = B->getSymbol();
   assert(!SA.isUndefined() && !SB.isUndefined());
-  if (!SA.getFragment() || !SB.getFragment())
+  MCFragment *FB = SB.getFragment();
+  if (!FB || !SA.getFragment())
     return false;
 
-  return isSymbolRefDifferenceFullyResolvedImpl(Asm, SA, SB, InSet);
-}
-
-bool MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
-    const MCAssembler &Asm, const MCSymbol &A, const MCSymbol &B,
-    bool InSet) const {
-  return isSymbolRefDifferenceFullyResolvedImpl(Asm, A, *B.getFragment(), InSet,
-                                                false);
+  return isSymbolRefDifferenceFullyResolvedImpl(Asm, SA, *FB, InSet, /*IsPCRel=*/false);
 }
 
 bool MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(

llvm/lib/MC/MachObjectWriter.cpp

@@ -661,18 +661,6 @@ void MachObjectWriter::executePostLayoutBinding(MCAssembler &Asm,
   bindIndirectSymbols(Asm);
 }
 
-bool MachObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
-    const MCAssembler &Asm, const MCSymbol &A, const MCSymbol &B,
-    bool InSet) const {
-  // FIXME: We don't handle things like
-  // foo = .
-  // creating atoms.
-  if (A.isVariable() || B.isVariable())
-    return false;
-  return MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(Asm, A, B,
-                                                                InSet);
-}
-
 bool MachObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
     const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB,
     bool InSet, bool IsPCRel) const {

llvm/test/MC/MachO/darwin-x86_64-diff-reloc-assign-2.s

@@ -9,20 +9,4 @@ L_var2:
 	.long L_var4 - L_var3
 
 // CHECK:      Relocations [
-// CHECK-NEXT:   Section __data {
-// CHECK-NEXT:     Relocation {
-// CHECK-NEXT:       Offset: 0x4
-// CHECK-NEXT:       PCRel: 0
-// CHECK-NEXT:       Length: 2
-// CHECK-NEXT:       Type: X86_64_RELOC_SUBTRACTOR (5)
-// CHECK-NEXT:       Section: __data (2)
-// CHECK-NEXT:     }
-// CHECK-NEXT:     Relocation {
-// CHECK-NEXT:       Offset: 0x4
-// CHECK-NEXT:       PCRel: 0
-// CHECK-NEXT:       Length: 2
-// CHECK-NEXT:       Type: X86_64_RELOC_UNSIGNED (0)
-// CHECK-NEXT:       Section: __data (2)
-// CHECK-NEXT:     }
-// CHECK-NEXT:   }
 // CHECK-NEXT: ]