1 //===-- llvm/CodeGen/SelectionDAG.h - InstSelection DAG ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
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.
8 //===----------------------------------------------------------------------===//
10 // This file declares the SelectionDAG class, and transitively defines the
11 // SDNode class and subclasses.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_SELECTIONDAG_H
16 #define LLVM_CODEGEN_SELECTIONDAG_H
18 #include "llvm/CodeGen/SelectionDAGNodes.h"
20 #include <string> // FIXME remove eventually, turning map into const char* map.
25 class MachineFunction;
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.
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
39 const TargetMachine &TM;
42 // Root - The root of the entire DAG. EntryNode - The starting token.
43 SDOperand Root, EntryNode;
45 // AllNodes - All of the nodes in the DAG
46 std::vector<SDNode*> AllNodes;
48 SelectionDAG(const TargetMachine &tm, MachineFunction &mf) : TM(tm), MF(mf) {
49 EntryNode = Root = getNode(ISD::EntryToken, MVT::Other);
53 MachineFunction &getMachineFunction() const { return MF; }
54 const TargetMachine &getTarget() { return TM; }
56 /// viewGraph - Pop up a ghostview window with the DAG rendered using 'dot'.
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(); }
65 /// getRoot - Return the root tag of the SelectionDAG.
67 const SDOperand &getRoot() const { return Root; }
69 /// getEntryNode - Return the token chain corresponding to the entry of the
71 const SDOperand &getEntryNode() const { return EntryNode; }
73 /// setRoot - Set the current root tag of the SelectionDAG.
75 const SDOperand &setRoot(SDOperand N) { return Root = N; }
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.
81 /// Note that this is an involved process that may invalidate pointers into
83 void Legalize(TargetLowering &TLI);
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);
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);
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);
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);
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);
121 /// getCall - Note that this destroys the vector of RetVals passed in.
123 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
125 SDNode *NN = new SDNode(ISD::CALL, Chain, Callee);
126 NN->setValueTypes(RetVals);
127 AllNodes.push_back(NN);
131 SDOperand getSetCC(ISD::CondCode, SDOperand LHS, SDOperand RHS);
133 /// getNode - Gets or creates the specified node.
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);
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);
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.
154 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr);
156 void replaceAllUsesWith(SDOperand Old, SDOperand New) {
157 assert(Old != New && "RAUW self!");
158 assert(0 && "Unimplemented!");
164 void DeleteNodeIfDead(SDNode *N, void *NodeSet);
166 // Maps to auto-CSE operations.
167 std::map<std::pair<unsigned, std::pair<SDOperand, MVT::ValueType> >,
169 std::map<std::pair<unsigned, std::pair<SDOperand, SDOperand> >,
172 std::map<std::pair<std::pair<SDOperand, SDOperand>, ISD::CondCode>,
173 SetCCSDNode*> SetCCs;
175 std::map<std::pair<SDOperand, std::pair<SDOperand, MVT::ValueType> >,
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;
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;
199 std::map<EVTStruct, SDNode*> MVTSDNodes;
202 template <> 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();
207 static nodes_iterator nodes_end(SelectionDAG *G) {
208 return G->allnodes_end();