1 files changed, 81 insertions, 0 deletions
diff --git a/lib/Target/Mips/MCTargetDesc/MipsDirectObjLower.cpp b/lib/Target/Mips/MCTargetDesc/MipsDirectObjLower.cpp
new file mode 100644
index 0000000..15c4282
--- /dev/null
+++ b/lib/Target/Mips/MCTargetDesc/MipsDirectObjLower.cpp
@@ -0,0 +1,81 @@
+//===-- MipsDirectObjLower.cpp - Mips LLVM direct object lowering -----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains code to lower Mips MCInst records that are normally
+// left to the assembler to lower such as large shifts.
+//
+//===----------------------------------------------------------------------===//
+#include "MipsInstrInfo.h"
+#include "MCTargetDesc/MipsDirectObjLower.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCStreamer.h"
+
+using namespace llvm;
+
+// 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
+void Mips::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
+void Mips::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;
+}