1 files changed, 57 insertions, 3 deletions

diff --git a/include/llvm/MC/MCFixup.h b/include/llvm/MC/MCFixup.h
index b83086c327f2..5f301eafc556 100644
--- a/include/llvm/MC/MCFixup.h
+++ b/include/llvm/MC/MCFixup.h
@@ -19,7 +19,7 @@
 namespace llvm {
 class MCExpr;
 
-/// \brief Extensible enumeration to represent the type of a fixup.
+/// Extensible enumeration to represent the type of a fixup.
 enum MCFixupKind {
   FK_Data_1 = 0, ///< A one-byte fixup.
   FK_Data_2,     ///< A two-byte fixup.
@@ -41,6 +41,14 @@ enum MCFixupKind {
   FK_SecRel_2,   ///< A two-byte section relative fixup.
   FK_SecRel_4,   ///< A four-byte section relative fixup.
   FK_SecRel_8,   ///< A eight-byte section relative fixup.
+  FK_Data_Add_1, ///< A one-byte add fixup.
+  FK_Data_Add_2, ///< A two-byte add fixup.
+  FK_Data_Add_4, ///< A four-byte add fixup.
+  FK_Data_Add_8, ///< A eight-byte add fixup.
+  FK_Data_Sub_1, ///< A one-byte sub fixup.
+  FK_Data_Sub_2, ///< A two-byte sub fixup.
+  FK_Data_Sub_4, ///< A four-byte sub fixup.
+  FK_Data_Sub_8, ///< A eight-byte sub fixup.
 
   FirstTargetFixupKind = 128,
 
@@ -49,7 +57,7 @@ enum MCFixupKind {
   MaxTargetFixupKind = (1 << 8)
 };
 
-/// \brief Encode information on a single operation to perform on a byte
+/// Encode information on a single operation to perform on a byte
 /// sequence (e.g., an encoded instruction) which requires assemble- or run-
 /// time patching.
 ///
@@ -90,6 +98,28 @@ public:
     return FI;
   }
 
+  /// Return a fixup corresponding to the add half of a add/sub fixup pair for
+  /// the given Fixup.
+  static MCFixup createAddFor(const MCFixup &Fixup) {
+    MCFixup FI;
+    FI.Value = Fixup.getValue();
+    FI.Offset = Fixup.getOffset();
+    FI.Kind = (unsigned)getAddKindForKind(Fixup.getKind());
+    FI.Loc = Fixup.getLoc();
+    return FI;
+  }
+
+  /// Return a fixup corresponding to the sub half of a add/sub fixup pair for
+  /// the given Fixup.
+  static MCFixup createSubFor(const MCFixup &Fixup) {
+    MCFixup FI;
+    FI.Value = Fixup.getValue();
+    FI.Offset = Fixup.getOffset();
+    FI.Kind = (unsigned)getSubKindForKind(Fixup.getKind());
+    FI.Loc = Fixup.getLoc();
+    return FI;
+  }
+
   MCFixupKind getKind() const { return MCFixupKind(Kind); }
 
   uint32_t getOffset() const { return Offset; }
@@ -97,7 +127,7 @@ public:
 
   const MCExpr *getValue() const { return Value; }
 
-  /// \brief Return the generic fixup kind for a value with the given size. It
+  /// Return the generic fixup kind for a value with the given size. It
   /// is an error to pass an unsupported size.
   static MCFixupKind getKindForSize(unsigned Size, bool isPCRel) {
     switch (Size) {
@@ -109,6 +139,30 @@ public:
     }
   }
 
+  /// Return the generic fixup kind for an addition with a given size. It
+  /// is an error to pass an unsupported size.
+  static MCFixupKind getAddKindForKind(unsigned Kind) {
+    switch (Kind) {
+    default: llvm_unreachable("Unknown type to convert!");
+    case FK_Data_1: return FK_Data_Add_1;
+    case FK_Data_2: return FK_Data_Add_2;
+    case FK_Data_4: return FK_Data_Add_4;
+    case FK_Data_8: return FK_Data_Add_8;
+    }
+  }
+
+  /// Return the generic fixup kind for an subtraction with a given size. It
+  /// is an error to pass an unsupported size.
+  static MCFixupKind getSubKindForKind(unsigned Kind) {
+    switch (Kind) {
+    default: llvm_unreachable("Unknown type to convert!");
+    case FK_Data_1: return FK_Data_Sub_1;
+    case FK_Data_2: return FK_Data_Sub_2;
+    case FK_Data_4: return FK_Data_Sub_4;
+    case FK_Data_8: return FK_Data_Sub_8;
+    }
+  }
+
   SMLoc getLoc() const { return Loc; }
 };