SelectionDAG.h revision 1cff05c7c216eea0e9173738c2a60b70c2b3c013
1//===-- llvm/CodeGen/SelectionDAG.h - InstSelection DAG ---------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file declares the SelectionDAG class, and transitively defines the 11// SDNode class and subclasses. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef LLVM_CODEGEN_SELECTIONDAG_H 16#define LLVM_CODEGEN_SELECTIONDAG_H 17 18#include "llvm/CodeGen/SelectionDAGNodes.h" 19#include <map> 20#include <string> // FIXME remove eventually, turning map into const char* map. 21 22namespace llvm { 23 class TargetLowering; 24 class TargetMachine; 25 class MachineFunction; 26 27/// SelectionDAG class - This is used to represent a portion of an LLVM function 28/// in a low-level Data Dependence DAG representation suitable for instruction 29/// selection. This DAG is constructed as the first step of instruction 30/// selection in order to allow implementation of machine specific optimizations 31/// and code simplifications. 32/// 33/// The representation used by the SelectionDAG is a target-independent 34/// representation, which has some similarities to the GCC RTL representation, 35/// but is significantly more simple, powerful, and is a graph form instead of a 36/// linear form. 37/// 38class SelectionDAG { 39 const TargetMachine &TM; 40 MachineFunction &MF; 41 42 // Root - The root of the entire DAG. EntryNode - The starting token. 43 SDOperand Root, EntryNode; 44 45 // AllNodes - All of the nodes in the DAG 46 std::vector<SDNode*> AllNodes; 47public: 48 SelectionDAG(const TargetMachine &tm, MachineFunction &mf) : TM(tm), MF(mf) { 49 EntryNode = Root = getNode(ISD::EntryToken, MVT::Other); 50 } 51 ~SelectionDAG(); 52 53 MachineFunction &getMachineFunction() const { return MF; } 54 const TargetMachine &getTarget() { return TM; } 55 56 /// viewGraph - Pop up a ghostview window with the DAG rendered using 'dot'. 57 /// 58 void viewGraph(); 59 60 61 typedef std::vector<SDNode*>::const_iterator allnodes_iterator; 62 allnodes_iterator allnodes_begin() const { return AllNodes.begin(); } 63 allnodes_iterator allnodes_end() const { return AllNodes.end(); } 64 65 /// getRoot - Return the root tag of the SelectionDAG. 66 /// 67 const SDOperand &getRoot() const { return Root; } 68 69 /// getEntryNode - Return the token chain corresponding to the entry of the 70 /// function. 71 const SDOperand &getEntryNode() const { return EntryNode; } 72 73 /// setRoot - Set the current root tag of the SelectionDAG. 74 /// 75 const SDOperand &setRoot(SDOperand N) { return Root = N; } 76 77 /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is 78 /// compatible with the target instruction selector, as indicated by the 79 /// TargetLowering object. 80 /// 81 /// Note that this is an involved process that may invalidate pointers into 82 /// the graph. 83 void Legalize(TargetLowering &TLI); 84 85 /// RemoveDeadNodes - This method deletes all unreachable nodes in the 86 /// SelectionDAG, including nodes (like loads) that have uses of their token 87 /// chain but no other uses and no side effect. If a node is passed in as an 88 /// argument, it is used as the seed for node deletion. 89 void RemoveDeadNodes(SDNode *N = 0); 90 91 SDOperand getConstant(uint64_t Val, MVT::ValueType VT); 92 SDOperand getConstantFP(double Val, MVT::ValueType VT); 93 SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT); 94 SDOperand getFrameIndex(int FI, MVT::ValueType VT); 95 SDOperand getConstantPool(unsigned CPIdx, MVT::ValueType VT); 96 SDOperand getBasicBlock(MachineBasicBlock *MBB); 97 SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT); 98 99 SDOperand getCopyToReg(SDOperand Chain, SDOperand N, unsigned Reg) { 100 // Note: these are auto-CSE'd because the caller doesn't make requests that 101 // could cause duplicates to occur. 102 SDNode *NN = new RegSDNode(ISD::CopyToReg, MVT::Other, Chain, N, Reg); 103 AllNodes.push_back(NN); 104 return SDOperand(NN, 0); 105 } 106 107 SDOperand getCopyFromReg(unsigned Reg, MVT::ValueType VT) { 108 // Note: These nodes are auto-CSE'd by the caller of this method. 109 SDNode *NN = new RegSDNode(ISD::CopyFromReg, VT, Reg); 110 AllNodes.push_back(NN); 111 return SDOperand(NN, 0); 112 } 113 114 SDOperand getImplicitDef(SDOperand Chain, unsigned Reg) { 115 // Note: These nodes are auto-CSE'd by the caller of this method. 116 SDNode *NN = new RegSDNode(ISD::ImplicitDef, MVT::Other, Chain, Reg); 117 AllNodes.push_back(NN); 118 return SDOperand(NN, 0); 119 } 120 121 /// getCall - Note that this destroys the vector of RetVals passed in. 122 /// 123 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain, 124 SDOperand Callee) { 125 SDNode *NN = new SDNode(ISD::CALL, Chain, Callee); 126 NN->setValueTypes(RetVals); 127 AllNodes.push_back(NN); 128 return NN; 129 } 130 131 SDOperand getSetCC(ISD::CondCode, SDOperand LHS, SDOperand RHS); 132 133 /// getNode - Gets or creates the specified node. 134 /// 135 SDOperand getNode(unsigned Opcode, MVT::ValueType VT); 136 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N); 137 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 138 SDOperand N1, SDOperand N2); 139 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 140 SDOperand N1, SDOperand N2, SDOperand N3); 141 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 142 std::vector<SDOperand> &Children); 143 144 // getNode - These versions take an extra value type for extending and 145 // truncating loads and stores. 146 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N1, 147 SDOperand N2, MVT::ValueType EVT); 148 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N1, 149 SDOperand N2, SDOperand N3, MVT::ValueType EVT); 150 151 /// getLoad - Loads are not normal binary operators: their result type is not 152 /// determined by their operands, and they produce a value AND a token chain. 153 /// 154 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr); 155 156 void replaceAllUsesWith(SDOperand Old, SDOperand New) { 157 assert(Old != New && "RAUW self!"); 158 assert(0 && "Unimplemented!"); 159 } 160 161 void dump() const; 162 163private: 164 void DeleteNodeIfDead(SDNode *N, void *NodeSet); 165 166 // Maps to auto-CSE operations. 167 std::map<std::pair<unsigned, std::pair<SDOperand, MVT::ValueType> >, 168 SDNode *> UnaryOps; 169 std::map<std::pair<unsigned, std::pair<SDOperand, SDOperand> >, 170 SDNode *> BinaryOps; 171 172 std::map<std::pair<std::pair<SDOperand, SDOperand>, ISD::CondCode>, 173 SetCCSDNode*> SetCCs; 174 175 std::map<std::pair<SDOperand, std::pair<SDOperand, MVT::ValueType> >, 176 SDNode *> Loads; 177 178 std::map<const GlobalValue*, SDNode*> GlobalValues; 179 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> Constants; 180 std::map<std::pair<double, MVT::ValueType>, SDNode*> ConstantFPs; 181 std::map<int, SDNode*> FrameIndices; 182 std::map<unsigned, SDNode*> ConstantPoolIndices; 183 std::map<MachineBasicBlock *, SDNode*> BBNodes; 184 std::map<std::string, SDNode*> ExternalSymbols; 185 struct EVTStruct { 186 unsigned Opcode; 187 MVT::ValueType VT, EVT; 188 std::vector<SDOperand> Ops; 189 bool operator<(const EVTStruct &RHS) const { 190 if (Opcode < RHS.Opcode) return true; 191 if (Opcode > RHS.Opcode) return false; 192 if (VT < RHS.VT) return true; 193 if (VT > RHS.VT) return false; 194 if (EVT < RHS.EVT) return true; 195 if (EVT > RHS.EVT) return false; 196 return Ops < RHS.Ops; 197 } 198 }; 199 std::map<EVTStruct, SDNode*> MVTSDNodes; 200}; 201 202template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> { 203 typedef SelectionDAG::allnodes_iterator nodes_iterator; 204 static nodes_iterator nodes_begin(SelectionDAG *G) { 205 return G->allnodes_begin(); 206 } 207 static nodes_iterator nodes_end(SelectionDAG *G) { 208 return G->allnodes_end(); 209 } 210}; 211 212} 213 214#endif 215