SelectionDAG.h revision 2d86ea21dd76647cb054fd5d27df9e49efc672b6
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 TargetLowering &TLI; 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(TargetLowering &tli, MachineFunction &mf) : TLI(tli), MF(mf) { 49 EntryNode = Root = getNode(ISD::EntryToken, MVT::Other); 50 } 51 ~SelectionDAG(); 52 53 MachineFunction &getMachineFunction() const { return MF; } 54 const TargetMachine &getTarget() const; 55 TargetLowering &getTargetLoweringInfo() const { return TLI; } 56 57 /// viewGraph - Pop up a ghostview window with the DAG rendered using 'dot'. 58 /// 59 void viewGraph(); 60 61 62 typedef std::vector<SDNode*>::const_iterator allnodes_iterator; 63 allnodes_iterator allnodes_begin() const { return AllNodes.begin(); } 64 allnodes_iterator allnodes_end() const { return AllNodes.end(); } 65 66 /// getRoot - Return the root tag of the SelectionDAG. 67 /// 68 const SDOperand &getRoot() const { return Root; } 69 70 /// getEntryNode - Return the token chain corresponding to the entry of the 71 /// function. 72 const SDOperand &getEntryNode() const { return EntryNode; } 73 74 /// setRoot - Set the current root tag of the SelectionDAG. 75 /// 76 const SDOperand &setRoot(SDOperand N) { return Root = N; } 77 78 /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is 79 /// compatible with the target instruction selector, as indicated by the 80 /// TargetLowering object. 81 /// 82 /// Note that this is an involved process that may invalidate pointers into 83 /// the graph. 84 void Legalize(); 85 86 /// RemoveDeadNodes - This method deletes all unreachable nodes in the 87 /// SelectionDAG, including nodes (like loads) that have uses of their token 88 /// chain but no other uses and no side effect. If a node is passed in as an 89 /// argument, it is used as the seed for node deletion. 90 void RemoveDeadNodes(SDNode *N = 0); 91 92 SDOperand getConstant(uint64_t Val, MVT::ValueType VT); 93 SDOperand getConstantFP(double Val, MVT::ValueType VT); 94 SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT); 95 SDOperand getFrameIndex(int FI, MVT::ValueType VT); 96 SDOperand getConstantPool(unsigned CPIdx, MVT::ValueType VT); 97 SDOperand getBasicBlock(MachineBasicBlock *MBB); 98 SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT); 99 100 SDOperand getCopyToReg(SDOperand Chain, SDOperand N, unsigned Reg) { 101 // Note: these are auto-CSE'd because the caller doesn't make requests that 102 // could cause duplicates to occur. 103 SDNode *NN = new RegSDNode(ISD::CopyToReg, Chain, N, Reg); 104 NN->setValueTypes(MVT::Other); 105 AllNodes.push_back(NN); 106 return SDOperand(NN, 0); 107 } 108 109 SDOperand getCopyFromReg(unsigned Reg, MVT::ValueType VT, SDOperand Chain) { 110 // Note: These nodes are auto-CSE'd by the caller of this method. 111 SDNode *NN = new RegSDNode(ISD::CopyFromReg, Chain, Reg); 112 NN->setValueTypes(VT, MVT::Other); 113 AllNodes.push_back(NN); 114 return SDOperand(NN, 0); 115 } 116 117 SDOperand getImplicitDef(SDOperand Chain, unsigned Reg) { 118 // Note: These nodes are auto-CSE'd by the caller of this method. 119 SDNode *NN = new RegSDNode(ISD::ImplicitDef, Chain, Reg); 120 NN->setValueTypes(MVT::Other); 121 AllNodes.push_back(NN); 122 return SDOperand(NN, 0); 123 } 124 125 /// getCall - Note that this destroys the vector of RetVals passed in. 126 /// 127 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain, 128 SDOperand Callee) { 129 SDNode *NN = new SDNode(ISD::CALL, Chain, Callee); 130 NN->setValueTypes(RetVals); 131 AllNodes.push_back(NN); 132 return NN; 133 } 134 135 /// getCall - This is identical to the one above, and should be used for calls 136 /// where arguments are passed in physical registers. This destroys the 137 /// RetVals and ArgsInRegs vectors. 138 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain, 139 SDOperand Callee, std::vector<SDOperand> &ArgsInRegs) { 140 ArgsInRegs.insert(ArgsInRegs.begin(), Callee); 141 ArgsInRegs.insert(ArgsInRegs.begin(), Chain); 142 SDNode *NN = new SDNode(ISD::CALL, ArgsInRegs); 143 NN->setValueTypes(RetVals); 144 AllNodes.push_back(NN); 145 return NN; 146 } 147 148 149 SDOperand getSetCC(ISD::CondCode, MVT::ValueType VT, 150 SDOperand LHS, SDOperand RHS); 151 152 /// getZeroExtendInReg - Return the expression required to zero extend the Op 153 /// value assuming it was the smaller SrcTy value. 154 SDOperand getZeroExtendInReg(SDOperand Op, MVT::ValueType SrcTy); 155 156 /// getNode - Gets or creates the specified node. 157 /// 158 SDOperand getNode(unsigned Opcode, MVT::ValueType VT); 159 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N); 160 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 161 SDOperand N1, SDOperand N2); 162 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 163 SDOperand N1, SDOperand N2, SDOperand N3); 164 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 165 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4); 166 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 167 std::vector<SDOperand> &Children); 168 169 // getNode - These versions take an extra value type for extending and 170 // truncating loads, stores, rounds, extends etc. 171 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N1, 172 SDOperand N2, MVT::ValueType EVT); 173 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, 174 SDOperand N, MVT::ValueType EVT); 175 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N1, 176 SDOperand N2, SDOperand N3, MVT::ValueType EVT); 177 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N1, 178 SDOperand N2, SDOperand N3, SDOperand N4, MVT::ValueType EVT); 179 180 /// getLoad - Loads are not normal binary operators: their result type is not 181 /// determined by their operands, and they produce a value AND a token chain. 182 /// 183 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr, SDOperand SV); 184 185 // getSrcValue - construct a node to track a Value* through the backend 186 SDOperand getSrcValue(const Value* I); 187 188 void replaceAllUsesWith(SDOperand Old, SDOperand New) { 189 assert(Old != New && "RAUW self!"); 190 assert(0 && "Unimplemented!"); 191 } 192 193 void dump() const; 194 195private: 196 void DeleteNodeIfDead(SDNode *N, void *NodeSet); 197 198 // Maps to auto-CSE operations. 199 std::map<std::pair<unsigned, std::pair<SDOperand, MVT::ValueType> >, 200 SDNode *> UnaryOps; 201 std::map<std::pair<unsigned, std::pair<SDOperand, SDOperand> >, 202 SDNode *> BinaryOps; 203 204 std::map<std::pair<std::pair<SDOperand, SDOperand>, 205 std::pair<ISD::CondCode, MVT::ValueType> >, 206 SetCCSDNode*> SetCCs; 207 208 std::map<std::pair<SDOperand, std::pair<SDOperand, MVT::ValueType> >, 209 SDNode *> Loads; 210 211 std::map<const GlobalValue*, SDNode*> GlobalValues; 212 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> Constants; 213 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> ConstantFPs; 214 std::map<int, SDNode*> FrameIndices; 215 std::map<unsigned, SDNode*> ConstantPoolIndices; 216 std::map<MachineBasicBlock *, SDNode*> BBNodes; 217 std::map<std::string, SDNode*> ExternalSymbols; 218 struct EVTStruct { 219 unsigned Opcode; 220 MVT::ValueType VT, EVT; 221 std::vector<SDOperand> Ops; 222 bool operator<(const EVTStruct &RHS) const { 223 if (Opcode < RHS.Opcode) return true; 224 if (Opcode > RHS.Opcode) return false; 225 if (VT < RHS.VT) return true; 226 if (VT > RHS.VT) return false; 227 if (EVT < RHS.EVT) return true; 228 if (EVT > RHS.EVT) return false; 229 return Ops < RHS.Ops; 230 } 231 }; 232 std::map<EVTStruct, SDNode*> MVTSDNodes; 233}; 234 235template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> { 236 typedef SelectionDAG::allnodes_iterator nodes_iterator; 237 static nodes_iterator nodes_begin(SelectionDAG *G) { 238 return G->allnodes_begin(); 239 } 240 static nodes_iterator nodes_end(SelectionDAG *G) { 241 return G->allnodes_end(); 242 } 243}; 244 245} 246 247#endif 248