1 files changed, 65 insertions, 3 deletions

diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp b/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
index 9460731..a464dfe 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -13,7 +13,6 @@
 //
 #define DEBUG_TYPE "mccodeemitter"
 #include "MCTargetDesc/MipsBaseInfo.h"
-#include "MCTargetDesc/MipsDirectObjLower.h"
 #include "MCTargetDesc/MipsFixupKinds.h"
 #include "MCTargetDesc/MipsMCTargetDesc.h"
 #include "llvm/ADT/APFloat.h"
@@ -114,6 +113,69 @@ MCCodeEmitter *llvm::createMipsMCCodeEmitterEL(const MCInstrInfo &MCII,
   return new MipsMCCodeEmitter(MCII, Ctx, STI, true);
 }
 
+
+// If the D<shift> instruction has a shift amount that is greater
+// than 31 (checked in calling routine), lower it to a D<shift>32 instruction
+static void LowerLargeShift(MCInst& Inst) {
+
+  assert(Inst.getNumOperands() == 3 && "Invalid no. of operands for shift!");
+  assert(Inst.getOperand(2).isImm());
+
+  int64_t Shift = Inst.getOperand(2).getImm();
+  if (Shift <= 31)
+    return; // Do nothing
+  Shift -= 32;
+
+  // saminus32
+  Inst.getOperand(2).setImm(Shift);
+
+  switch (Inst.getOpcode()) {
+  default:
+    // Calling function is not synchronized
+    llvm_unreachable("Unexpected shift instruction");
+  case Mips::DSLL:
+    Inst.setOpcode(Mips::DSLL32);
+    return;
+  case Mips::DSRL:
+    Inst.setOpcode(Mips::DSRL32);
+    return;
+  case Mips::DSRA:
+    Inst.setOpcode(Mips::DSRA32);
+    return;
+  }
+}
+
+// Pick a DEXT or DINS instruction variant based on the pos and size operands
+static void LowerDextDins(MCInst& InstIn) {
+  int Opcode = InstIn.getOpcode();
+
+  if (Opcode == Mips::DEXT)
+    assert(InstIn.getNumOperands() == 4 &&
+           "Invalid no. of machine operands for DEXT!");
+  else // Only DEXT and DINS are possible
+    assert(InstIn.getNumOperands() == 5 &&
+           "Invalid no. of machine operands for DINS!");
+
+  assert(InstIn.getOperand(2).isImm());
+  int64_t pos = InstIn.getOperand(2).getImm();
+  assert(InstIn.getOperand(3).isImm());
+  int64_t size = InstIn.getOperand(3).getImm();
+
+  if (size <= 32) {
+    if (pos < 32)  // DEXT/DINS, do nothing
+      return;
+    // DEXTU/DINSU
+    InstIn.getOperand(2).setImm(pos - 32);
+    InstIn.setOpcode((Opcode == Mips::DEXT) ? Mips::DEXTU : Mips::DINSU);
+    return;
+  }
+  // DEXTM/DINSM
+  assert(pos < 32 && "DEXT/DINS cannot have both size and pos > 32");
+  InstIn.getOperand(3).setImm(size - 32);
+  InstIn.setOpcode((Opcode == Mips::DEXT) ? Mips::DEXTM : Mips::DINSM);
+  return;
+}
+
 /// EncodeInstruction - Emit the instruction.
 /// Size the instruction (currently only 4 bytes
 void MipsMCCodeEmitter::
@@ -131,12 +193,12 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS,
   case Mips::DSLL:
   case Mips::DSRL:
   case Mips::DSRA:
-    Mips::LowerLargeShift(TmpInst);
+    LowerLargeShift(TmpInst);
     break;
     // Double extract instruction is chosen by pos and size operands
   case Mips::DEXT:
   case Mips::DINS:
-    Mips::LowerDextDins(TmpInst);
+    LowerDextDins(TmpInst);
   }
 
   uint32_t Binary = getBinaryCodeForInstr(TmpInst, Fixups);