Change XCoreAsmPrinter to lower MachineInstrs to MCInsts before emission.

This change adds XCoreMCInstLower to do the lowering to MCInst and
XCoreInstPrinter to print the MCInsts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170288 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/XCore/XCoreMCInstLower.cpp

@@ -0,0 +1,116 @@
+//===-- XCoreMCInstLower.cpp - Convert XCore MachineInstr to MCInst -------===//
+//
+//                     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 XCore MachineInstrs to their corresponding
+// MCInst records.
+//
+//===----------------------------------------------------------------------===//
+#include "XCoreMCInstLower.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/Target/Mangler.h"
+
+using namespace llvm;
+
+XCoreMCInstLower::XCoreMCInstLower(class AsmPrinter &asmprinter)
+: Printer(asmprinter) {}
+
+void XCoreMCInstLower::Initialize(Mangler *M, MCContext *C) {
+  Mang = M;
+  Ctx = C;
+}
+
+MCOperand XCoreMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
+                                               MachineOperandType MOTy,
+                                               unsigned Offset) const {
+  MCSymbolRefExpr::VariantKind Kind = MCSymbolRefExpr::VK_None;
+  const MCSymbol *Symbol;
+
+  switch (MOTy) {
+    case MachineOperand::MO_MachineBasicBlock:
+      Symbol = MO.getMBB()->getSymbol();
+      break;
+    case MachineOperand::MO_GlobalAddress:
+      Symbol = Mang->getSymbol(MO.getGlobal());
+      Offset += MO.getOffset();
+      break;
+    case MachineOperand::MO_BlockAddress:
+      Symbol = Printer.GetBlockAddressSymbol(MO.getBlockAddress());
+      Offset += MO.getOffset();
+      break;
+    case MachineOperand::MO_ExternalSymbol:
+      Symbol = Printer.GetExternalSymbolSymbol(MO.getSymbolName());
+      Offset += MO.getOffset();
+      break;
+    case MachineOperand::MO_JumpTableIndex:
+      Symbol = Printer.GetJTISymbol(MO.getIndex());
+      break;
+    case MachineOperand::MO_ConstantPoolIndex:
+      Symbol = Printer.GetCPISymbol(MO.getIndex());
+      Offset += MO.getOffset();
+      break;
+    default:
+      llvm_unreachable("<unknown operand type>");
+  }
+
+  const MCSymbolRefExpr *MCSym = MCSymbolRefExpr::Create(Symbol, Kind, *Ctx);
+
+  if (!Offset)
+    return MCOperand::CreateExpr(MCSym);
+
+  // Assume offset is never negative.
+  assert(Offset > 0);
+
+  const MCConstantExpr *OffsetExpr =  MCConstantExpr::Create(Offset, *Ctx);
+  const MCBinaryExpr *Add = MCBinaryExpr::CreateAdd(MCSym, OffsetExpr, *Ctx);
+  return MCOperand::CreateExpr(Add);
+}
+
+MCOperand XCoreMCInstLower::LowerOperand(const MachineOperand &MO,
+                                         unsigned offset) const {
+  MachineOperandType MOTy = MO.getType();
+
+  switch (MOTy) {
+    default: llvm_unreachable("unknown operand type");
+    case MachineOperand::MO_Register:
+      // Ignore all implicit register operands.
+      if (MO.isImplicit()) break;
+      return MCOperand::CreateReg(MO.getReg());
+    case MachineOperand::MO_Immediate:
+      return MCOperand::CreateImm(MO.getImm() + offset);
+    case MachineOperand::MO_MachineBasicBlock:
+    case MachineOperand::MO_GlobalAddress:
+    case MachineOperand::MO_ExternalSymbol:
+    case MachineOperand::MO_JumpTableIndex:
+    case MachineOperand::MO_ConstantPoolIndex:
+    case MachineOperand::MO_BlockAddress:
+      return LowerSymbolOperand(MO, MOTy, offset);
+    case MachineOperand::MO_RegisterMask:
+      break;
+  }
+
+  return MCOperand();
+}
+
+void XCoreMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
+  OutMI.setOpcode(MI->getOpcode());
+
+  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &MO = MI->getOperand(i);
+    MCOperand MCOp = LowerOperand(MO);
+
+    if (MCOp.isValid())
+      OutMI.addOperand(MCOp);
+  }
+}