Create a new InstrEmitter class for translating SelectionDAG nodes

into MachineInstrs. This is mostly just moving the code from
ScheduleDAGSDNodesEmit.cpp into a new class. This decouples MachineInstr
emitting from scheduling.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83699 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 119 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.h b/lib/CodeGen/SelectionDAG/InstrEmitter.h
new file mode 100644
index 0000000000..bb4634d04b
--- /dev/null
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.h
@@ -0,0 +1,119 @@
+//===---- InstrEmitter.h - Emit MachineInstrs for the SelectionDAG class ---==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This declares the Emit routines for the SelectionDAG class, which creates
+// MachineInstrs based on the decisions of the SelectionDAG instruction
+// selection.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef INSTREMITTER_H
+#define INSTREMITTER_H
+
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/ADT/DenseMap.h"
+
+namespace llvm {
+
+class TargetInstrDesc;
+
+class InstrEmitter {
+  MachineFunction *MF;
+  MachineRegisterInfo *MRI;
+  const TargetMachine *TM;
+  const TargetInstrInfo *TII;
+  const TargetRegisterInfo *TRI;
+  const TargetLowering *TLI;
+
+  MachineBasicBlock *MBB;
+  MachineBasicBlock::iterator InsertPos;
+
+  /// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
+  /// implicit physical register output.
+  void EmitCopyFromReg(SDNode *Node, unsigned ResNo,
+                       bool IsClone, bool IsCloned,
+                       unsigned SrcReg,
+                       DenseMap<SDValue, unsigned> &VRBaseMap);
+
+  /// getDstOfCopyToRegUse - If the only use of the specified result number of
+  /// node is a CopyToReg, return its destination register. Return 0 otherwise.
+  unsigned getDstOfOnlyCopyToRegUse(SDNode *Node,
+                                    unsigned ResNo) const;
+
+  void CreateVirtualRegisters(SDNode *Node, MachineInstr *MI,
+                              const TargetInstrDesc &II,
+                              bool IsClone, bool IsCloned,
+                              DenseMap<SDValue, unsigned> &VRBaseMap);
+
+  /// getVR - Return the virtual register corresponding to the specified result
+  /// of the specified node.
+  unsigned getVR(SDValue Op,
+                 DenseMap<SDValue, unsigned> &VRBaseMap);
+
+  /// AddRegisterOperand - Add the specified register as an operand to the
+  /// specified machine instr. Insert register copies if the register is
+  /// not in the required register class.
+  void AddRegisterOperand(MachineInstr *MI, SDValue Op,
+                          unsigned IIOpNum,
+                          const TargetInstrDesc *II,
+                          DenseMap<SDValue, unsigned> &VRBaseMap);
+
+  /// AddOperand - Add the specified operand to the specified machine instr.  II
+  /// specifies the instruction information for the node, and IIOpNum is the
+  /// operand number (in the II) that we are adding. IIOpNum and II are used for
+  /// assertions only.
+  void AddOperand(MachineInstr *MI, SDValue Op,
+                  unsigned IIOpNum,
+                  const TargetInstrDesc *II,
+                  DenseMap<SDValue, unsigned> &VRBaseMap);
+
+  /// EmitSubregNode - Generate machine code for subreg nodes.
+  ///
+  void EmitSubregNode(SDNode *Node, DenseMap<SDValue, unsigned> &VRBaseMap);
+
+  /// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes.
+  /// COPY_TO_REGCLASS is just a normal copy, except that the destination
+  /// register is constrained to be in a particular register class.
+  ///
+  void EmitCopyToRegClassNode(SDNode *Node,
+                              DenseMap<SDValue, unsigned> &VRBaseMap);
+
+public:
+  /// CountResults - The results of target nodes have register or immediate
+  /// operands first, then an optional chain, and optional flag operands
+  /// (which do not go into the machine instrs.)
+  static unsigned CountResults(SDNode *Node);
+
+  /// CountOperands - The inputs to target nodes have any actual inputs first,
+  /// followed by an optional chain operand, then flag operands.  Compute
+  /// the number of actual operands that will go into the resulting
+  /// MachineInstr.
+  static unsigned CountOperands(SDNode *Node);
+
+  /// EmitNode - Generate machine code for an node and needed dependencies.
+  ///
+  void EmitNode(SDNode *Node, bool IsClone, bool IsCloned,
+                DenseMap<SDValue, unsigned> &VRBaseMap,
+                DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM);
+
+  /// getBlock - Return the current basic block.
+  MachineBasicBlock *getBlock() { return MBB; }
+
+  /// getInsertPos - Return the current insertion position.
+  MachineBasicBlock::iterator getInsertPos() { return InsertPos; }
+
+  /// InstrEmitter - Construct an InstrEmitter and set it to start inserting
+  /// at the given position in the given block.
+  InstrEmitter(MachineBasicBlock *mbb, MachineBasicBlock::iterator insertpos);
+};
+
+}
+
+#endif