1//===-- llvm/CodeGen/SelectionDAGISel.h - Common Base Class------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the SelectionDAGISel class, which is used as the common
11// base class for SelectionDAG-based instruction selectors.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CODEGEN_SELECTIONDAG_ISEL_H
16#define LLVM_CODEGEN_SELECTIONDAG_ISEL_H
17
18#include "llvm/BasicBlock.h"
19#include "llvm/Pass.h"
20#include "llvm/CodeGen/SelectionDAG.h"
21#include "llvm/CodeGen/MachineFunctionPass.h"
22
23namespace llvm {
24  class FastISel;
25  class SelectionDAGBuilder;
26  class SDValue;
27  class MachineRegisterInfo;
28  class MachineBasicBlock;
29  class MachineFunction;
30  class MachineInstr;
31  class TargetLowering;
32  class TargetLibraryInfo;
33  class TargetInstrInfo;
34  class FunctionLoweringInfo;
35  class ScheduleHazardRecognizer;
36  class GCFunctionInfo;
37  class ScheduleDAGSDNodes;
38  class LoadInst;
39
40/// SelectionDAGISel - This is the common base class used for SelectionDAG-based
41/// pattern-matching instruction selectors.
42class SelectionDAGISel : public MachineFunctionPass {
43public:
44  const TargetMachine &TM;
45  const TargetLowering &TLI;
46  const TargetLibraryInfo *LibInfo;
47  FunctionLoweringInfo *FuncInfo;
48  MachineFunction *MF;
49  MachineRegisterInfo *RegInfo;
50  SelectionDAG *CurDAG;
51  SelectionDAGBuilder *SDB;
52  AliasAnalysis *AA;
53  GCFunctionInfo *GFI;
54  CodeGenOpt::Level OptLevel;
55  static char ID;
56
57  explicit SelectionDAGISel(const TargetMachine &tm,
58                            CodeGenOpt::Level OL = CodeGenOpt::Default);
59  virtual ~SelectionDAGISel();
60
61  const TargetLowering &getTargetLowering() { return TLI; }
62
63  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
64
65  virtual bool runOnMachineFunction(MachineFunction &MF);
66
67  virtual void EmitFunctionEntryCode() {}
68
69  /// PreprocessISelDAG - This hook allows targets to hack on the graph before
70  /// instruction selection starts.
71  virtual void PreprocessISelDAG() {}
72
73  /// PostprocessISelDAG() - This hook allows the target to hack on the graph
74  /// right after selection.
75  virtual void PostprocessISelDAG() {}
76
77  /// Select - Main hook targets implement to select a node.
78  virtual SDNode *Select(SDNode *N) = 0;
79
80  /// SelectInlineAsmMemoryOperand - Select the specified address as a target
81  /// addressing mode, according to the specified constraint code.  If this does
82  /// not match or is not implemented, return true.  The resultant operands
83  /// (which will appear in the machine instruction) should be added to the
84  /// OutOps vector.
85  virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
86                                            char ConstraintCode,
87                                            std::vector<SDValue> &OutOps) {
88    return true;
89  }
90
91  /// IsProfitableToFold - Returns true if it's profitable to fold the specific
92  /// operand node N of U during instruction selection that starts at Root.
93  virtual bool IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const;
94
95  /// IsLegalToFold - Returns true if the specific operand node N of
96  /// U can be folded during instruction selection that starts at Root.
97  /// FIXME: This is a static member function because the MSP430/X86
98  /// targets, which uses it during isel.  This could become a proper member.
99  static bool IsLegalToFold(SDValue N, SDNode *U, SDNode *Root,
100                            CodeGenOpt::Level OptLevel,
101                            bool IgnoreChains = false);
102
103  // Opcodes used by the DAG state machine:
104  enum BuiltinOpcodes {
105    OPC_Scope,
106    OPC_RecordNode,
107    OPC_RecordChild0, OPC_RecordChild1, OPC_RecordChild2, OPC_RecordChild3,
108    OPC_RecordChild4, OPC_RecordChild5, OPC_RecordChild6, OPC_RecordChild7,
109    OPC_RecordMemRef,
110    OPC_CaptureGlueInput,
111    OPC_MoveChild,
112    OPC_MoveParent,
113    OPC_CheckSame,
114    OPC_CheckPatternPredicate,
115    OPC_CheckPredicate,
116    OPC_CheckOpcode,
117    OPC_SwitchOpcode,
118    OPC_CheckType,
119    OPC_SwitchType,
120    OPC_CheckChild0Type, OPC_CheckChild1Type, OPC_CheckChild2Type,
121    OPC_CheckChild3Type, OPC_CheckChild4Type, OPC_CheckChild5Type,
122    OPC_CheckChild6Type, OPC_CheckChild7Type,
123    OPC_CheckInteger,
124    OPC_CheckCondCode,
125    OPC_CheckValueType,
126    OPC_CheckComplexPat,
127    OPC_CheckAndImm, OPC_CheckOrImm,
128    OPC_CheckFoldableChainNode,
129
130    OPC_EmitInteger,
131    OPC_EmitRegister,
132    OPC_EmitRegister2,
133    OPC_EmitConvertToTarget,
134    OPC_EmitMergeInputChains,
135    OPC_EmitMergeInputChains1_0,
136    OPC_EmitMergeInputChains1_1,
137    OPC_EmitCopyToReg,
138    OPC_EmitNodeXForm,
139    OPC_EmitNode,
140    OPC_MorphNodeTo,
141    OPC_MarkGlueResults,
142    OPC_CompleteMatch
143  };
144
145  enum {
146    OPFL_None       = 0,  // Node has no chain or glue input and isn't variadic.
147    OPFL_Chain      = 1,     // Node has a chain input.
148    OPFL_GlueInput  = 2,     // Node has a glue input.
149    OPFL_GlueOutput = 4,     // Node has a glue output.
150    OPFL_MemRefs    = 8,     // Node gets accumulated MemRefs.
151    OPFL_Variadic0  = 1<<4,  // Node is variadic, root has 0 fixed inputs.
152    OPFL_Variadic1  = 2<<4,  // Node is variadic, root has 1 fixed inputs.
153    OPFL_Variadic2  = 3<<4,  // Node is variadic, root has 2 fixed inputs.
154    OPFL_Variadic3  = 4<<4,  // Node is variadic, root has 3 fixed inputs.
155    OPFL_Variadic4  = 5<<4,  // Node is variadic, root has 4 fixed inputs.
156    OPFL_Variadic5  = 6<<4,  // Node is variadic, root has 5 fixed inputs.
157    OPFL_Variadic6  = 7<<4,  // Node is variadic, root has 6 fixed inputs.
158
159    OPFL_VariadicInfo = OPFL_Variadic6
160  };
161
162  /// getNumFixedFromVariadicInfo - Transform an EmitNode flags word into the
163  /// number of fixed arity values that should be skipped when copying from the
164  /// root.
165  static inline int getNumFixedFromVariadicInfo(unsigned Flags) {
166    return ((Flags&OPFL_VariadicInfo) >> 4)-1;
167  }
168
169
170protected:
171  /// DAGSize - Size of DAG being instruction selected.
172  ///
173  unsigned DAGSize;
174
175  /// ISelPosition - Node iterator marking the current position of
176  /// instruction selection as it procedes through the topologically-sorted
177  /// node list.
178  SelectionDAG::allnodes_iterator ISelPosition;
179
180
181  /// ISelUpdater - helper class to handle updates of the
182  /// instruction selection graph.
183  class ISelUpdater : public SelectionDAG::DAGUpdateListener {
184    virtual void anchor();
185    SelectionDAG::allnodes_iterator &ISelPosition;
186  public:
187    explicit ISelUpdater(SelectionDAG::allnodes_iterator &isp)
188      : ISelPosition(isp) {}
189
190    /// NodeDeleted - Handle nodes deleted from the graph. If the
191    /// node being deleted is the current ISelPosition node, update
192    /// ISelPosition.
193    ///
194    virtual void NodeDeleted(SDNode *N, SDNode *E) {
195      if (ISelPosition == SelectionDAG::allnodes_iterator(N))
196        ++ISelPosition;
197    }
198
199    /// NodeUpdated - Ignore updates for now.
200    virtual void NodeUpdated(SDNode *N) {}
201  };
202
203  /// ReplaceUses - replace all uses of the old node F with the use
204  /// of the new node T.
205  void ReplaceUses(SDValue F, SDValue T) {
206    ISelUpdater ISU(ISelPosition);
207    CurDAG->ReplaceAllUsesOfValueWith(F, T, &ISU);
208  }
209
210  /// ReplaceUses - replace all uses of the old nodes F with the use
211  /// of the new nodes T.
212  void ReplaceUses(const SDValue *F, const SDValue *T, unsigned Num) {
213    ISelUpdater ISU(ISelPosition);
214    CurDAG->ReplaceAllUsesOfValuesWith(F, T, Num, &ISU);
215  }
216
217  /// ReplaceUses - replace all uses of the old node F with the use
218  /// of the new node T.
219  void ReplaceUses(SDNode *F, SDNode *T) {
220    ISelUpdater ISU(ISelPosition);
221    CurDAG->ReplaceAllUsesWith(F, T, &ISU);
222  }
223
224
225  /// SelectInlineAsmMemoryOperands - Calls to this are automatically generated
226  /// by tblgen.  Others should not call it.
227  void SelectInlineAsmMemoryOperands(std::vector<SDValue> &Ops);
228
229
230public:
231  // Calls to these predicates are generated by tblgen.
232  bool CheckAndMask(SDValue LHS, ConstantSDNode *RHS,
233                    int64_t DesiredMaskS) const;
234  bool CheckOrMask(SDValue LHS, ConstantSDNode *RHS,
235                    int64_t DesiredMaskS) const;
236
237
238  /// CheckPatternPredicate - This function is generated by tblgen in the
239  /// target.  It runs the specified pattern predicate and returns true if it
240  /// succeeds or false if it fails.  The number is a private implementation
241  /// detail to the code tblgen produces.
242  virtual bool CheckPatternPredicate(unsigned PredNo) const {
243    llvm_unreachable("Tblgen should generate the implementation of this!");
244  }
245
246  /// CheckNodePredicate - This function is generated by tblgen in the target.
247  /// It runs node predicate number PredNo and returns true if it succeeds or
248  /// false if it fails.  The number is a private implementation
249  /// detail to the code tblgen produces.
250  virtual bool CheckNodePredicate(SDNode *N, unsigned PredNo) const {
251    llvm_unreachable("Tblgen should generate the implementation of this!");
252  }
253
254  virtual bool CheckComplexPattern(SDNode *Root, SDNode *Parent, SDValue N,
255                                   unsigned PatternNo,
256                        SmallVectorImpl<std::pair<SDValue, SDNode*> > &Result) {
257    llvm_unreachable("Tblgen should generate the implementation of this!");
258  }
259
260  virtual SDValue RunSDNodeXForm(SDValue V, unsigned XFormNo) {
261    llvm_unreachable("Tblgen should generate this!");
262  }
263
264  SDNode *SelectCodeCommon(SDNode *NodeToMatch,
265                           const unsigned char *MatcherTable,
266                           unsigned TableSize);
267
268private:
269
270  // Calls to these functions are generated by tblgen.
271  SDNode *Select_INLINEASM(SDNode *N);
272  SDNode *Select_UNDEF(SDNode *N);
273  void CannotYetSelect(SDNode *N);
274
275private:
276  void DoInstructionSelection();
277  SDNode *MorphNode(SDNode *Node, unsigned TargetOpc, SDVTList VTs,
278                    const SDValue *Ops, unsigned NumOps, unsigned EmitNodeInfo);
279
280  void PrepareEHLandingPad();
281  void SelectAllBasicBlocks(const Function &Fn);
282  bool TryToFoldFastISelLoad(const LoadInst *LI, const Instruction *FoldInst,
283                             FastISel *FastIS);
284  void FinishBasicBlock();
285
286  void SelectBasicBlock(BasicBlock::const_iterator Begin,
287                        BasicBlock::const_iterator End,
288                        bool &HadTailCall);
289  void CodeGenAndEmitDAG();
290  void LowerArguments(const BasicBlock *BB);
291
292  void ComputeLiveOutVRegInfo();
293
294  /// Create the scheduler. If a specific scheduler was specified
295  /// via the SchedulerRegistry, use it, otherwise select the
296  /// one preferred by the target.
297  ///
298  ScheduleDAGSDNodes *CreateScheduler();
299
300  /// OpcodeOffset - This is a cache used to dispatch efficiently into isel
301  /// state machines that start with a OPC_SwitchOpcode node.
302  std::vector<unsigned> OpcodeOffset;
303
304  void UpdateChainsAndGlue(SDNode *NodeToMatch, SDValue InputChain,
305                           const SmallVectorImpl<SDNode*> &ChainNodesMatched,
306                           SDValue InputGlue, const SmallVectorImpl<SDNode*> &F,
307                           bool isMorphNodeTo);
308
309};
310
311}
312
313#endif /* LLVM_CODEGEN_SELECTIONDAG_ISEL_H */
314