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);
103 SDOperand getValueType(MVT::ValueType);
105 SDOperand getCopyToReg(SDOperand Chain, SDOperand N, unsigned Reg) {
106 // Note: these are auto-CSE'd because the caller doesn't make requests that
107 // could cause duplicates to occur.
108 SDNode *NN = new RegSDNode(ISD::CopyToReg, Chain, N, Reg);
109 NN->setValueTypes(MVT::Other);
110 AllNodes.push_back(NN);
111 return SDOperand(NN, 0);
114 SDOperand getCopyFromReg(unsigned Reg, MVT::ValueType VT, SDOperand Chain) {
115 // Note: These nodes are auto-CSE'd by the caller of this method.
116 SDNode *NN = new RegSDNode(ISD::CopyFromReg, Chain, Reg);
117 NN->setValueTypes(VT, MVT::Other);
118 AllNodes.push_back(NN);
119 return SDOperand(NN, 0);
122 SDOperand getImplicitDef(SDOperand Chain, unsigned Reg) {
123 // Note: These nodes are auto-CSE'd by the caller of this method.
124 SDNode *NN = new RegSDNode(ISD::ImplicitDef, Chain, Reg);
125 NN->setValueTypes(MVT::Other);
126 AllNodes.push_back(NN);
127 return SDOperand(NN, 0);
130 /// getCall - Note that this destroys the vector of RetVals passed in.
132 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
133 SDOperand Callee, bool isTailCall = false) {
134 SDNode *NN = new SDNode(isTailCall ? ISD::TAILCALL : ISD::CALL, Chain,
136 NN->setValueTypes(RetVals);
137 AllNodes.push_back(NN);
141 /// getCall - This is identical to the one above, and should be used for calls
142 /// where arguments are passed in physical registers. This destroys the
143 /// RetVals and ArgsInRegs vectors.
144 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
145 SDOperand Callee, std::vector<SDOperand> &ArgsInRegs,
146 bool isTailCall = false) {
147 ArgsInRegs.insert(ArgsInRegs.begin(), Callee);
148 ArgsInRegs.insert(ArgsInRegs.begin(), Chain);
149 SDNode *NN = new SDNode(isTailCall ? ISD::TAILCALL : ISD::CALL, ArgsInRegs);
150 NN->setValueTypes(RetVals);
151 AllNodes.push_back(NN);
155 SDOperand getCondCode(ISD::CondCode Cond);
157 /// getZeroExtendInReg - Return the expression required to zero extend the Op
158 /// value assuming it was the smaller SrcTy value.
159 SDOperand getZeroExtendInReg(SDOperand Op, MVT::ValueType SrcTy);
161 /// getNode - Gets or creates the specified node.
163 SDOperand getNode(unsigned Opcode, MVT::ValueType VT);
164 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N);
165 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
166 SDOperand N1, SDOperand N2);
167 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
168 SDOperand N1, SDOperand N2, SDOperand N3);
169 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
170 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4);
171 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
172 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4,
174 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
175 std::vector<SDOperand> &Children);
176 SDOperand getNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
177 std::vector<SDOperand> &Ops);
179 /// getSetCC - Helper function to make it easier to build SetCC's if you just
180 /// have an ISD::CondCode instead of an SDOperand.
182 SDOperand getSetCC(MVT::ValueType VT, SDOperand LHS, SDOperand RHS,
183 ISD::CondCode Cond) {
184 return getNode(ISD::SETCC, VT, LHS, RHS, getCondCode(Cond));
187 /// getSelectCC - Helper function to make it easier to build SelectCC's if you
188 /// just have an ISD::CondCode instead of an SDOperand.
190 SDOperand getSelectCC(SDOperand LHS, SDOperand RHS,
191 SDOperand True, SDOperand False, ISD::CondCode Cond) {
192 MVT::ValueType VT = True.getValueType();
193 assert(LHS.getValueType() == RHS.getValueType() &&
194 "LHS and RHS of condition must have same type!");
195 assert(True.getValueType() == False.getValueType() &&
196 "True and False arms of SelectCC must have same type!");
197 return getNode(ISD::SELECT_CC, VT, LHS, RHS, True, False,getCondCode(Cond));
200 /// getLoad - Loads are not normal binary operators: their result type is not
201 /// determined by their operands, and they produce a value AND a token chain.
203 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
205 SDOperand getExtLoad(unsigned Opcode, MVT::ValueType VT, SDOperand Chain,
206 SDOperand Ptr, SDOperand SV, MVT::ValueType EVT);
208 // getSrcValue - construct a node to track a Value* through the backend
209 SDOperand getSrcValue(const Value* I, int offset = 0);
211 void replaceAllUsesWith(SDOperand Old, SDOperand New) {
212 assert(Old != New && "RAUW self!");
213 assert(0 && "Unimplemented!");
219 void DeleteNodeIfDead(SDNode *N, void *NodeSet);
221 // Try to simplify a setcc built with the specified operands and cc. If
222 // unable to simplify it, return a null SDOperand.
223 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N1,
224 SDOperand N2, ISD::CondCode Cond);
227 // Maps to auto-CSE operations.
228 std::map<std::pair<unsigned, std::pair<SDOperand, MVT::ValueType> >,
230 std::map<std::pair<unsigned, std::pair<SDOperand, SDOperand> >,
233 std::vector<CondCodeSDNode*> CondCodeNodes;
235 std::map<std::pair<SDOperand, std::pair<SDOperand, MVT::ValueType> >,
238 std::map<const GlobalValue*, SDNode*> GlobalValues;
239 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> Constants;
240 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> ConstantFPs;
241 std::map<int, SDNode*> FrameIndices;
242 std::map<unsigned, SDNode*> ConstantPoolIndices;
243 std::map<MachineBasicBlock *, SDNode*> BBNodes;
244 std::vector<SDNode*> ValueTypeNodes;
245 std::map<std::string, SDNode*> ExternalSymbols;
246 std::map<std::pair<unsigned,
247 std::pair<MVT::ValueType, std::vector<SDOperand> > >,
248 SDNode*> OneResultNodes;
249 std::map<std::pair<unsigned,
250 std::pair<std::vector<MVT::ValueType>,
251 std::vector<SDOperand> > >,
252 SDNode*> ArbitraryNodes;
255 template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
256 typedef SelectionDAG::allnodes_iterator nodes_iterator;
257 static nodes_iterator nodes_begin(SelectionDAG *G) {
258 return G->allnodes_begin();
260 static nodes_iterator nodes_end(SelectionDAG *G) {
261 return G->allnodes_end();