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