Move InstrSelection into lib/Target/Sparc, as it's sparc specific.  This
makes the incestuous #include'ing of sparc internal headers much less
disturbing.  :)

llvm-svn: 10729
diff --git a/llvm/lib/Target/Sparc/InstrSelection/InstrSelectionSupport.cpp b/llvm/lib/Target/Sparc/InstrSelection/InstrSelectionSupport.cpp
new file mode 100644
index 0000000..e8b8785
--- /dev/null
+++ b/llvm/lib/Target/Sparc/InstrSelection/InstrSelectionSupport.cpp
@@ -0,0 +1,268 @@
+//===-- InstrSelectionSupport.cpp -----------------------------------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// Target-independent instruction selection code.  See SparcInstrSelection.cpp
+// for usage.
+// 
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/InstrSelectionSupport.h"
+#include "llvm/CodeGen/InstrSelection.h"
+#include "llvm/CodeGen/MachineInstrAnnot.h"
+#include "llvm/CodeGen/MachineCodeForInstruction.h"
+#include "llvm/CodeGen/InstrForest.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegInfo.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Constants.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/DerivedTypes.h"
+#include "../SparcInstrSelectionSupport.h"
+
+namespace llvm {
+
+// Generate code to load the constant into a TmpInstruction (virtual reg) and
+// returns the virtual register.
+// 
+static TmpInstruction*
+InsertCodeToLoadConstant(Function *F,
+                         Value* opValue,
+                         Instruction* vmInstr,
+                         std::vector<MachineInstr*>& loadConstVec,
+                         TargetMachine& target)
+{
+  // Create a tmp virtual register to hold the constant.
+  MachineCodeForInstruction &mcfi = MachineCodeForInstruction::get(vmInstr);
+  TmpInstruction* tmpReg = new TmpInstruction(mcfi, opValue);
+  
+  target.getInstrInfo().CreateCodeToLoadConst(target, F, opValue, tmpReg,
+                                              loadConstVec, mcfi);
+  
+  // Record the mapping from the tmp VM instruction to machine instruction.
+  // Do this for all machine instructions that were not mapped to any
+  // other temp values created by 
+  // tmpReg->addMachineInstruction(loadConstVec.back());
+  
+  return tmpReg;
+}
+
+
+MachineOperand::MachineOperandType
+ChooseRegOrImmed(int64_t intValue,
+                 bool isSigned,
+		 MachineOpCode opCode,
+		 const TargetMachine& target,
+		 bool canUseImmed,
+		 unsigned int& getMachineRegNum,
+		 int64_t& getImmedValue)
+{
+  MachineOperand::MachineOperandType opType=MachineOperand::MO_VirtualRegister;
+  getMachineRegNum = 0;
+  getImmedValue = 0;
+
+  if (canUseImmed &&
+      target.getInstrInfo().constantFitsInImmedField(opCode, intValue)) {
+      opType = isSigned? MachineOperand::MO_SignExtendedImmed
+                       : MachineOperand::MO_UnextendedImmed;
+      getImmedValue = intValue;
+  } else if (intValue == 0 && target.getRegInfo().getZeroRegNum() >= 0) {
+    opType = MachineOperand::MO_MachineRegister;
+    getMachineRegNum = target.getRegInfo().getZeroRegNum();
+  }
+
+  return opType;
+}
+
+
+MachineOperand::MachineOperandType
+ChooseRegOrImmed(Value* val,
+		 MachineOpCode opCode,
+		 const TargetMachine& target,
+		 bool canUseImmed,
+		 unsigned int& getMachineRegNum,
+		 int64_t& getImmedValue)
+{
+  getMachineRegNum = 0;
+  getImmedValue = 0;
+
+  // To use reg or immed, constant needs to be integer, bool, or a NULL pointer
+  // TargetInstrInfo::ConvertConstantToIntType() does the right conversions:
+  bool isValidConstant;
+  uint64_t valueToUse =
+    target.getInstrInfo().ConvertConstantToIntType(target, val, val->getType(),
+                                                   isValidConstant);
+  if (! isValidConstant)
+    return MachineOperand::MO_VirtualRegister;
+
+  // Now check if the constant value fits in the IMMED field.
+  // 
+  return ChooseRegOrImmed((int64_t) valueToUse, val->getType()->isSigned(),
+                          opCode, target, canUseImmed,
+                          getMachineRegNum, getImmedValue);
+}
+
+//---------------------------------------------------------------------------
+// Function: FixConstantOperandsForInstr
+// 
+// Purpose:
+// Special handling for constant operands of a machine instruction
+// -- if the constant is 0, use the hardwired 0 register, if any;
+// -- if the constant fits in the IMMEDIATE field, use that field;
+// -- else create instructions to put the constant into a register, either
+//    directly or by loading explicitly from the constant pool.
+// 
+// In the first 2 cases, the operand of `minstr' is modified in place.
+// Returns a vector of machine instructions generated for operands that
+// fall under case 3; these must be inserted before `minstr'.
+//---------------------------------------------------------------------------
+
+std::vector<MachineInstr*>
+FixConstantOperandsForInstr(Instruction* vmInstr,
+                            MachineInstr* minstr,
+                            TargetMachine& target)
+{
+  std::vector<MachineInstr*> MVec;
+  
+  MachineOpCode opCode = minstr->getOpCode();
+  const TargetInstrInfo& instrInfo = target.getInstrInfo();
+  int resultPos = instrInfo.getResultPos(opCode);
+  int immedPos = instrInfo.getImmedConstantPos(opCode);
+
+  Function *F = vmInstr->getParent()->getParent();
+
+  for (unsigned op=0; op < minstr->getNumOperands(); op++)
+    {
+      const MachineOperand& mop = minstr->getOperand(op);
+          
+      // Skip the result position, preallocated machine registers, or operands
+      // that cannot be constants (CC regs or PC-relative displacements)
+      if (resultPos == (int)op ||
+          mop.getType() == MachineOperand::MO_MachineRegister ||
+          mop.getType() == MachineOperand::MO_CCRegister ||
+          mop.getType() == MachineOperand::MO_PCRelativeDisp)
+        continue;
+
+      bool constantThatMustBeLoaded = false;
+      unsigned int machineRegNum = 0;
+      int64_t immedValue = 0;
+      Value* opValue = NULL;
+      MachineOperand::MachineOperandType opType =
+        MachineOperand::MO_VirtualRegister;
+
+      // Operand may be a virtual register or a compile-time constant
+      if (mop.getType() == MachineOperand::MO_VirtualRegister) {
+        assert(mop.getVRegValue() != NULL);
+        opValue = mop.getVRegValue();
+        if (Constant *opConst = dyn_cast<Constant>(opValue)) {
+          opType = ChooseRegOrImmed(opConst, opCode, target,
+                                    (immedPos == (int)op), machineRegNum,
+                                    immedValue);
+          if (opType == MachineOperand::MO_VirtualRegister)
+            constantThatMustBeLoaded = true;
+        }
+      } else {
+        //
+        // If the operand is from the constant pool, don't try to change it.
+        //
+        if (mop.getType() == MachineOperand::MO_ConstantPoolIndex) {
+          continue;
+        }
+        assert(mop.isImmediate());
+        bool isSigned = mop.getType() == MachineOperand::MO_SignExtendedImmed;
+
+        // Bit-selection flags indicate an instruction that is extracting
+        // bits from its operand so ignore this even if it is a big constant.
+        if (mop.isHiBits32() || mop.isLoBits32() ||
+            mop.isHiBits64() || mop.isLoBits64())
+          continue;
+
+        opType = ChooseRegOrImmed(mop.getImmedValue(), isSigned,
+                                  opCode, target, (immedPos == (int)op), 
+                                  machineRegNum, immedValue);
+
+        if (opType == MachineOperand::MO_SignExtendedImmed ||
+            opType == MachineOperand::MO_UnextendedImmed) {
+          // The optype is an immediate value
+          // This means we need to change the opcode, e.g. ADDr -> ADDi
+          unsigned newOpcode = convertOpcodeFromRegToImm(opCode);
+          minstr->setOpcode(newOpcode);
+        }
+
+        if (opType == mop.getType()) 
+          continue;           // no change: this is the most common case
+
+        if (opType == MachineOperand::MO_VirtualRegister) {
+          constantThatMustBeLoaded = true;
+          opValue = isSigned
+            ? (Value*)ConstantSInt::get(Type::LongTy, immedValue)
+            : (Value*)ConstantUInt::get(Type::ULongTy,(uint64_t)immedValue);
+        }
+      }
+
+      if (opType == MachineOperand::MO_MachineRegister)
+        minstr->SetMachineOperandReg(op, machineRegNum);
+      else if (opType == MachineOperand::MO_SignExtendedImmed ||
+               opType == MachineOperand::MO_UnextendedImmed) {
+        minstr->SetMachineOperandConst(op, opType, immedValue);
+        // The optype is or has become an immediate
+        // This means we need to change the opcode, e.g. ADDr -> ADDi
+        unsigned newOpcode = convertOpcodeFromRegToImm(opCode);
+        minstr->setOpcode(newOpcode);
+      } else if (constantThatMustBeLoaded ||
+               (opValue && isa<GlobalValue>(opValue)))
+        { // opValue is a constant that must be explicitly loaded into a reg
+          assert(opValue);
+          TmpInstruction* tmpReg = InsertCodeToLoadConstant(F, opValue, vmInstr,
+                                                            MVec, target);
+          minstr->SetMachineOperandVal(op, MachineOperand::MO_VirtualRegister,
+                                       tmpReg);
+        }
+    }
+  
+  // Also, check for implicit operands used by the machine instruction
+  // (no need to check those defined since they cannot be constants).
+  // These include:
+  // -- arguments to a Call
+  // -- return value of a Return
+  // Any such operand that is a constant value needs to be fixed also.
+  // The current instructions with implicit refs (viz., Call and Return)
+  // have no immediate fields, so the constant always needs to be loaded
+  // into a register.
+  // 
+  bool isCall = instrInfo.isCall(opCode);
+  unsigned lastCallArgNum = 0;          // unused if not a call
+  CallArgsDescriptor* argDesc = NULL;   // unused if not a call
+  if (isCall)
+    argDesc = CallArgsDescriptor::get(minstr);
+  
+  for (unsigned i=0, N=minstr->getNumImplicitRefs(); i < N; ++i)
+    if (isa<Constant>(minstr->getImplicitRef(i)) ||
+        isa<GlobalValue>(minstr->getImplicitRef(i)))
+      {
+        Value* oldVal = minstr->getImplicitRef(i);
+        TmpInstruction* tmpReg =
+          InsertCodeToLoadConstant(F, oldVal, vmInstr, MVec, target);
+        minstr->setImplicitRef(i, tmpReg);
+        
+        if (isCall) {
+          // find and replace the argument in the CallArgsDescriptor
+          unsigned i=lastCallArgNum;
+          while (argDesc->getArgInfo(i).getArgVal() != oldVal)
+            ++i;
+          assert(i < argDesc->getNumArgs() &&
+                 "Constant operands to a call *must* be in the arg list");
+          lastCallArgNum = i;
+          argDesc->getArgInfo(i).replaceArgVal(tmpReg);
+        }
+      }
+  
+  return MVec;
+}
+
+} // End llvm namespace