1 //===-- llvm/CodeGen/SelectionDAGISel.h - Common Base Class------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the SelectionDAGISel class, which is used as the common
11 // base class for SelectionDAG-based instruction selectors.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_SELECTIONDAGISEL_H
16 #define LLVM_CODEGEN_SELECTIONDAGISEL_H
18 #include "llvm/CodeGen/MachineFunctionPass.h"
19 #include "llvm/CodeGen/SelectionDAG.h"
20 #include "llvm/IR/BasicBlock.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Target/TargetSubtargetInfo.h"
26 class SelectionDAGBuilder;
28 class MachineRegisterInfo;
29 class MachineBasicBlock;
30 class MachineFunction;
33 class TargetLibraryInfo;
34 class FunctionLoweringInfo;
35 class ScheduleHazardRecognizer;
37 class ScheduleDAGSDNodes;
40 /// SelectionDAGISel - This is the common base class used for SelectionDAG-based
41 /// pattern-matching instruction selectors.
42 class SelectionDAGISel : public MachineFunctionPass {
45 const TargetLibraryInfo *LibInfo;
46 FunctionLoweringInfo *FuncInfo;
48 MachineRegisterInfo *RegInfo;
50 SelectionDAGBuilder *SDB;
53 CodeGenOpt::Level OptLevel;
54 const TargetInstrInfo *TII;
55 const TargetLowering *TLI;
59 explicit SelectionDAGISel(TargetMachine &tm,
60 CodeGenOpt::Level OL = CodeGenOpt::Default);
61 ~SelectionDAGISel() override;
63 const TargetLowering *getTargetLowering() const { return TLI; }
65 void getAnalysisUsage(AnalysisUsage &AU) const override;
67 bool runOnMachineFunction(MachineFunction &MF) override;
69 virtual void EmitFunctionEntryCode() {}
71 /// PreprocessISelDAG - This hook allows targets to hack on the graph before
72 /// instruction selection starts.
73 virtual void PreprocessISelDAG() {}
75 /// PostprocessISelDAG() - This hook allows the target to hack on the graph
76 /// right after selection.
77 virtual void PostprocessISelDAG() {}
79 /// Main hook for targets to transform nodes into machine nodes.
80 virtual void Select(SDNode *N) = 0;
82 /// SelectInlineAsmMemoryOperand - Select the specified address as a target
83 /// addressing mode, according to the specified constraint. If this does
84 /// not match or is not implemented, return true. The resultant operands
85 /// (which will appear in the machine instruction) should be added to the
87 virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
88 unsigned ConstraintID,
89 std::vector<SDValue> &OutOps) {
93 /// IsProfitableToFold - Returns true if it's profitable to fold the specific
94 /// operand node N of U during instruction selection that starts at Root.
95 virtual bool IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const;
97 /// IsLegalToFold - Returns true if the specific operand node N of
98 /// U can be folded during instruction selection that starts at Root.
99 /// FIXME: This is a static member function because the MSP430/X86
100 /// targets, which uses it during isel. This could become a proper member.
101 static bool IsLegalToFold(SDValue N, SDNode *U, SDNode *Root,
102 CodeGenOpt::Level OptLevel,
103 bool IgnoreChains = false);
105 // Opcodes used by the DAG state machine:
106 enum BuiltinOpcodes {
109 OPC_RecordChild0, OPC_RecordChild1, OPC_RecordChild2, OPC_RecordChild3,
110 OPC_RecordChild4, OPC_RecordChild5, OPC_RecordChild6, OPC_RecordChild7,
112 OPC_CaptureGlueInput,
114 OPC_MoveChild0, OPC_MoveChild1, OPC_MoveChild2, OPC_MoveChild3,
115 OPC_MoveChild4, OPC_MoveChild5, OPC_MoveChild6, OPC_MoveChild7,
118 OPC_CheckChild0Same, OPC_CheckChild1Same,
119 OPC_CheckChild2Same, OPC_CheckChild3Same,
120 OPC_CheckPatternPredicate,
126 OPC_CheckChild0Type, OPC_CheckChild1Type, OPC_CheckChild2Type,
127 OPC_CheckChild3Type, OPC_CheckChild4Type, OPC_CheckChild5Type,
128 OPC_CheckChild6Type, OPC_CheckChild7Type,
130 OPC_CheckChild0Integer, OPC_CheckChild1Integer, OPC_CheckChild2Integer,
131 OPC_CheckChild3Integer, OPC_CheckChild4Integer,
135 OPC_CheckAndImm, OPC_CheckOrImm,
136 OPC_CheckFoldableChainNode,
141 OPC_EmitConvertToTarget,
142 OPC_EmitMergeInputChains,
143 OPC_EmitMergeInputChains1_0,
144 OPC_EmitMergeInputChains1_1,
145 OPC_EmitMergeInputChains1_2,
149 // Space-optimized forms that implicitly encode number of result VTs.
150 OPC_EmitNode0, OPC_EmitNode1, OPC_EmitNode2,
152 // Space-optimized forms that implicitly encode number of result VTs.
153 OPC_MorphNodeTo0, OPC_MorphNodeTo1, OPC_MorphNodeTo2,
158 OPFL_None = 0, // Node has no chain or glue input and isn't variadic.
159 OPFL_Chain = 1, // Node has a chain input.
160 OPFL_GlueInput = 2, // Node has a glue input.
161 OPFL_GlueOutput = 4, // Node has a glue output.
162 OPFL_MemRefs = 8, // Node gets accumulated MemRefs.
163 OPFL_Variadic0 = 1<<4, // Node is variadic, root has 0 fixed inputs.
164 OPFL_Variadic1 = 2<<4, // Node is variadic, root has 1 fixed inputs.
165 OPFL_Variadic2 = 3<<4, // Node is variadic, root has 2 fixed inputs.
166 OPFL_Variadic3 = 4<<4, // Node is variadic, root has 3 fixed inputs.
167 OPFL_Variadic4 = 5<<4, // Node is variadic, root has 4 fixed inputs.
168 OPFL_Variadic5 = 6<<4, // Node is variadic, root has 5 fixed inputs.
169 OPFL_Variadic6 = 7<<4, // Node is variadic, root has 6 fixed inputs.
171 OPFL_VariadicInfo = OPFL_Variadic6
174 /// getNumFixedFromVariadicInfo - Transform an EmitNode flags word into the
175 /// number of fixed arity values that should be skipped when copying from the
177 static inline int getNumFixedFromVariadicInfo(unsigned Flags) {
178 return ((Flags&OPFL_VariadicInfo) >> 4)-1;
183 /// DAGSize - Size of DAG being instruction selected.
187 /// ReplaceUses - replace all uses of the old node F with the use
188 /// of the new node T.
189 void ReplaceUses(SDValue F, SDValue T) {
190 CurDAG->ReplaceAllUsesOfValueWith(F, T);
193 /// ReplaceUses - replace all uses of the old nodes F with the use
194 /// of the new nodes T.
195 void ReplaceUses(const SDValue *F, const SDValue *T, unsigned Num) {
196 CurDAG->ReplaceAllUsesOfValuesWith(F, T, Num);
199 /// ReplaceUses - replace all uses of the old node F with the use
200 /// of the new node T.
201 void ReplaceUses(SDNode *F, SDNode *T) {
202 CurDAG->ReplaceAllUsesWith(F, T);
205 /// Replace all uses of \c F with \c T, then remove \c F from the DAG.
206 void ReplaceNode(SDNode *F, SDNode *T) {
207 CurDAG->ReplaceAllUsesWith(F, T);
208 CurDAG->RemoveDeadNode(F);
211 /// SelectInlineAsmMemoryOperands - Calls to this are automatically generated
212 /// by tblgen. Others should not call it.
213 void SelectInlineAsmMemoryOperands(std::vector<SDValue> &Ops,
217 // Calls to these predicates are generated by tblgen.
218 bool CheckAndMask(SDValue LHS, ConstantSDNode *RHS,
219 int64_t DesiredMaskS) const;
220 bool CheckOrMask(SDValue LHS, ConstantSDNode *RHS,
221 int64_t DesiredMaskS) const;
224 /// CheckPatternPredicate - This function is generated by tblgen in the
225 /// target. It runs the specified pattern predicate and returns true if it
226 /// succeeds or false if it fails. The number is a private implementation
227 /// detail to the code tblgen produces.
228 virtual bool CheckPatternPredicate(unsigned PredNo) const {
229 llvm_unreachable("Tblgen should generate the implementation of this!");
232 /// CheckNodePredicate - This function is generated by tblgen in the target.
233 /// It runs node predicate number PredNo and returns true if it succeeds or
234 /// false if it fails. The number is a private implementation
235 /// detail to the code tblgen produces.
236 virtual bool CheckNodePredicate(SDNode *N, unsigned PredNo) const {
237 llvm_unreachable("Tblgen should generate the implementation of this!");
240 virtual bool CheckComplexPattern(SDNode *Root, SDNode *Parent, SDValue N,
242 SmallVectorImpl<std::pair<SDValue, SDNode*> > &Result) {
243 llvm_unreachable("Tblgen should generate the implementation of this!");
246 virtual SDValue RunSDNodeXForm(SDValue V, unsigned XFormNo) {
247 llvm_unreachable("Tblgen should generate this!");
250 void SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
253 /// \brief Return true if complex patterns for this target can mutate the
255 virtual bool ComplexPatternFuncMutatesDAG() const {
261 // Calls to these functions are generated by tblgen.
262 void Select_INLINEASM(SDNode *N);
263 void Select_READ_REGISTER(SDNode *N);
264 void Select_WRITE_REGISTER(SDNode *N);
265 void Select_UNDEF(SDNode *N);
266 void CannotYetSelect(SDNode *N);
269 void DoInstructionSelection();
270 SDNode *MorphNode(SDNode *Node, unsigned TargetOpc, SDVTList VTs,
271 ArrayRef<SDValue> Ops, unsigned EmitNodeInfo);
273 /// Prepares the landing pad to take incoming values or do other EH
274 /// personality specific tasks. Returns true if the block should be
275 /// instruction selected, false if no code should be emitted for it.
276 bool PrepareEHLandingPad();
278 /// \brief Perform instruction selection on all basic blocks in the function.
279 void SelectAllBasicBlocks(const Function &Fn);
281 /// \brief Perform instruction selection on a single basic block, for
282 /// instructions between \p Begin and \p End. \p HadTailCall will be set
283 /// to true if a call in the block was translated as a tail call.
284 void SelectBasicBlock(BasicBlock::const_iterator Begin,
285 BasicBlock::const_iterator End,
287 void FinishBasicBlock();
289 void CodeGenAndEmitDAG();
291 /// \brief Generate instructions for lowering the incoming arguments of the
293 void LowerArguments(const Function &F);
295 void ComputeLiveOutVRegInfo();
297 /// Create the scheduler. If a specific scheduler was specified
298 /// via the SchedulerRegistry, use it, otherwise select the
299 /// one preferred by the target.
301 ScheduleDAGSDNodes *CreateScheduler();
303 /// OpcodeOffset - This is a cache used to dispatch efficiently into isel
304 /// state machines that start with a OPC_SwitchOpcode node.
305 std::vector<unsigned> OpcodeOffset;
307 void UpdateChains(SDNode *NodeToMatch, SDValue InputChain,
308 SmallVectorImpl<SDNode *> &ChainNodesMatched,
314 #endif /* LLVM_CODEGEN_SELECTIONDAGISEL_H */