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 // Maps to auto-CSE operations.
49 std::map<std::pair<unsigned, std::pair<SDOperand, MVT::ValueType> >,
51 std::map<std::pair<unsigned, std::pair<SDOperand, SDOperand> >,
54 std::map<std::pair<std::pair<SDOperand, SDOperand>, ISD::CondCode>,
57 std::map<std::pair<SDOperand, std::pair<SDOperand, MVT::ValueType> >,
60 std::map<const GlobalValue*, SDNode*> GlobalValues;
61 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> Constants;
62 std::map<std::pair<double, MVT::ValueType>, SDNode*> ConstantFPs;
63 std::map<int, SDNode*> FrameIndices;
64 std::map<unsigned, SDNode*> ConstantPoolIndices;
65 std::map<MachineBasicBlock *, SDNode*> BBNodes;
66 std::map<std::string, SDNode*> ExternalSymbols;
68 SelectionDAG(const TargetMachine &tm, MachineFunction &mf) : TM(tm), MF(mf) {
69 EntryNode = Root = getNode(ISD::EntryToken, MVT::Other);
73 MachineFunction &getMachineFunction() const { return MF; }
74 const TargetMachine &getTarget() { return TM; }
76 /// viewGraph - Pop up a ghostview window with the DAG rendered using 'dot'.
81 typedef std::vector<SDNode*>::const_iterator allnodes_iterator;
82 allnodes_iterator allnodes_begin() const { return AllNodes.begin(); }
83 allnodes_iterator allnodes_end() const { return AllNodes.end(); }
85 /// getRoot - Return the root tag of the SelectionDAG.
87 const SDOperand &getRoot() const { return Root; }
89 /// getEntryNode - Return the token chain corresponding to the entry of the
91 const SDOperand &getEntryNode() const { return EntryNode; }
93 /// setRoot - Set the current root tag of the SelectionDAG.
95 const SDOperand &setRoot(SDOperand N) { return Root = N; }
97 /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
98 /// compatible with the target instruction selector, as indicated by the
99 /// TargetLowering object.
101 /// Note that this is an involved process that may invalidate pointers into
103 void Legalize(TargetLowering &TLI);
105 /// RemoveDeadNodes - This method deletes all unreachable nodes in the
106 /// SelectionDAG, including nodes (like loads) that have uses of their token
107 /// chain but no other uses and no side effect. If a node is passed in as an
108 /// argument, it is used as the seed for node deletion.
109 void RemoveDeadNodes(SDNode *N = 0);
111 SDOperand getConstant(uint64_t Val, MVT::ValueType VT);
112 SDOperand getConstantFP(double Val, MVT::ValueType VT);
113 SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT);
114 SDOperand getFrameIndex(int FI, MVT::ValueType VT);
115 SDOperand getConstantPool(unsigned CPIdx, MVT::ValueType VT);
116 SDOperand getBasicBlock(MachineBasicBlock *MBB);
117 SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT);
119 SDOperand getCopyToReg(SDOperand Chain, SDOperand N, unsigned Reg) {
120 // Note: these are auto-CSE'd because the caller doesn't make requests that
121 // could cause duplicates to occur.
122 SDNode *NN = new CopyRegSDNode(Chain, N, Reg);
123 AllNodes.push_back(NN);
124 return SDOperand(NN, 0);
127 SDOperand getCopyFromReg(unsigned Reg, MVT::ValueType VT) {
128 // Note: These nodes are auto-CSE'd by the caller of this method.
129 SDNode *NN = new CopyRegSDNode(Reg, VT);
130 AllNodes.push_back(NN);
131 return SDOperand(NN, 0);
134 /// getCall - Note that this destroys the vector of RetVals passed in.
136 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
138 SDNode *NN = new SDNode(ISD::CALL, Chain, Callee);
139 NN->setValueTypes(RetVals);
140 AllNodes.push_back(NN);
144 SDOperand getSetCC(ISD::CondCode, SDOperand LHS, SDOperand RHS);
146 /// getNode - Gets or creates the specified node.
148 SDOperand getNode(unsigned Opcode, MVT::ValueType VT);
149 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N);
150 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
151 SDOperand N1, SDOperand N2);
152 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
153 SDOperand N1, SDOperand N2, SDOperand N3);
154 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
155 std::vector<SDOperand> &Children);
157 /// getLoad - Loads are not normal binary operators: their result type is not
158 /// determined by their operands, and they produce a value AND a token chain.
160 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr);
162 void replaceAllUsesWith(SDOperand Old, SDOperand New) {
163 assert(Old != New && "RAUW self!");
164 assert(0 && "Unimplemented!");
170 void DeleteNodeIfDead(SDNode *N, void *NodeSet);
173 template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
174 typedef SelectionDAG::allnodes_iterator nodes_iterator;
175 static nodes_iterator nodes_begin(SelectionDAG *G) {
176 return G->allnodes_begin();
178 static nodes_iterator nodes_end(SelectionDAG *G) {
179 return G->allnodes_end();