lib/Target/PIC16/PIC16ISelDAGToDAG.cpp

   1 //===-- PIC16ISelDAGToDAG.cpp - A dag to dag inst selector for PIC16 ------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file defines an instruction selector for the PIC16 target.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #define DEBUG_TYPE "pic16-isel"
  15
  16 #include "PIC16ISelDAGToDAG.h"
  17 #include "llvm/Support/Debug.h"
  18
  19 using namespace llvm;
  20
  21 /// createPIC16ISelDag - This pass converts a legalized DAG into a
  22 /// PIC16-specific DAG, ready for instruction scheduling.
  23 FunctionPass *llvm::createPIC16ISelDag(PIC16TargetMachine &TM) {
  24   return new PIC16DAGToDAGISel(TM);
  25 }
  26
  27
  28 /// InstructionSelect - This callback is invoked by
  29 /// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
  30 void PIC16DAGToDAGISel::InstructionSelect() {
  31   DEBUG(BB->dump());
  32   SelectRoot(*CurDAG);
  33   CurDAG->RemoveDeadNodes();
  34 }
  35
  36 /// Select - Select instructions not customized! Used for
  37 /// expanded, promoted and normal instructions.
  38 SDNode* PIC16DAGToDAGISel::Select(SDValue N) {
  39
  40   // Select the default instruction.
  41   SDNode *ResNode = SelectCode(N);
  42
  43   return ResNode;
  44 }
  45
  46
  47 // SelectDirectAddr - Match a direct address for DAG.
  48 // A direct address could be a globaladdress or externalsymbol.
  49 bool PIC16DAGToDAGISel::SelectDirectAddr(SDValue Op, SDValue N,
  50                                       SDValue &Address) {
  51   // Return true if TGA or ES.
  52   if (N.getOpcode() == ISD::TargetGlobalAddress
  53       || N.getOpcode() == ISD::TargetExternalSymbol) {
  54     Address = N;
  55     return true;
  56   }
  57
  58   return false;
  59 }