TargetInstrInfo.h revision e4d32f6cf96566f8d37e50212e4f67330150ee20 
1//===-- llvm/Target/TargetInstrInfo.h - Instruction Info --------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
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.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file describes the target machine instructions to the code generator.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_TARGET_TARGETINSTRINFO_H
15#define LLVM_TARGET_TARGETINSTRINFO_H
16
17#include "llvm/CodeGen/MachineBasicBlock.h"
18#include "Support/DataTypes.h"
19#include <vector>
20#include <cassert>
21
22namespace llvm {
23
24class MachineInstr;
25class TargetMachine;
26class Value;
27class Type;
28class Instruction;
29class Constant;
30class Function;
31class MachineCodeForInstruction;
32
33//---------------------------------------------------------------------------
34// Data types used to define information about a single machine instruction
35//---------------------------------------------------------------------------
36
37typedef short MachineOpCode;
38typedef unsigned InstrSchedClass;
39
40//---------------------------------------------------------------------------
41// struct TargetInstrDescriptor:
42//	Predefined information about each machine instruction.
43//	Designed to initialized statically.
44//
45
46const unsigned M_NOP_FLAG		= 1 << 0;
47const unsigned M_BRANCH_FLAG		= 1 << 1;
48const unsigned M_CALL_FLAG		= 1 << 2;
49const unsigned M_RET_FLAG		= 1 << 3;
50const unsigned M_BARRIER_FLAG           = 1 << 4;
51const unsigned M_CC_FLAG		= 1 << 6;
52const unsigned M_LOAD_FLAG		= 1 << 10;
53const unsigned M_STORE_FLAG		= 1 << 12;
54const unsigned M_DUMMY_PHI_FLAG	= 1 << 13;
55const unsigned M_PSEUDO_FLAG           = 1 << 14;       // Pseudo instruction
56// 3-addr instructions which really work like 2-addr ones, eg. X86 add/sub
57const unsigned M_2_ADDR_FLAG           = 1 << 15;
58
59// M_TERMINATOR_FLAG - Is this instruction part of the terminator for a basic
60// block?  Typically this is things like return and branch instructions.
61// Various passes use this to insert code into the bottom of a basic block, but
62// before control flow occurs.
63const unsigned M_TERMINATOR_FLAG       = 1 << 16;
64
65struct TargetInstrDescriptor {
66  const char *    Name;          // Assembly language mnemonic for the opcode.
67  int             numOperands;   // Number of args; -1 if variable #args
68  int             resultPos;     // Position of the result; -1 if no result
69  unsigned        maxImmedConst; // Largest +ve constant in IMMED field or 0.
70  bool	          immedIsSignExtended; // Is IMMED field sign-extended? If so,
71                                 //   smallest -ve value is -(maxImmedConst+1).
72  unsigned        numDelaySlots; // Number of delay slots after instruction
73  unsigned        latency;       // Latency in machine cycles
74  InstrSchedClass schedClass;    // enum  identifying instr sched class
75  unsigned        Flags;         // flags identifying machine instr class
76  unsigned        TSFlags;       // Target Specific Flag values
77  const unsigned *ImplicitUses;  // Registers implicitly read by this instr
78  const unsigned *ImplicitDefs;  // Registers implicitly defined by this instr
79};
80
81
82//---------------------------------------------------------------------------
83///
84/// TargetInstrInfo - Interface to description of machine instructions
85///
86class TargetInstrInfo {
87  const TargetInstrDescriptor* desc;    // raw array to allow static init'n
88  unsigned NumOpcodes;                  // number of entries in the desc array
89  unsigned numRealOpCodes;              // number of non-dummy op codes
90
91  TargetInstrInfo(const TargetInstrInfo &);  // DO NOT IMPLEMENT
92  void operator=(const TargetInstrInfo &);   // DO NOT IMPLEMENT
93public:
94  TargetInstrInfo(const TargetInstrDescriptor *desc, unsigned NumOpcodes);
95  virtual ~TargetInstrInfo();
96
97  // Invariant: All instruction sets use opcode #0 as the PHI instruction
98  enum { PHI = 0 };
99
100  unsigned getNumOpcodes() const { return NumOpcodes; }
101
102  /// get - Return the machine instruction descriptor that corresponds to the
103  /// specified instruction opcode.
104  ///
105  const TargetInstrDescriptor& get(MachineOpCode Opcode) const {
106    assert((unsigned)Opcode < NumOpcodes);
107    return desc[Opcode];
108  }
109
110  const char *getName(MachineOpCode Opcode) const {
111    return get(Opcode).Name;
112  }
113
114  int getNumOperands(MachineOpCode Opcode) const {
115    return get(Opcode).numOperands;
116  }
117
118
119  InstrSchedClass getSchedClass(MachineOpCode Opcode) const {
120    return get(Opcode).schedClass;
121  }
122
123  const unsigned *getImplicitUses(MachineOpCode Opcode) const {
124    return get(Opcode).ImplicitUses;
125  }
126
127  const unsigned *getImplicitDefs(MachineOpCode Opcode) const {
128    return get(Opcode).ImplicitDefs;
129  }
130
131
132  //
133  // Query instruction class flags according to the machine-independent
134  // flags listed above.
135  //
136  bool isReturn(MachineOpCode Opcode) const {
137    return get(Opcode).Flags & M_RET_FLAG;
138  }
139
140  bool isPseudoInstr(MachineOpCode Opcode) const {
141    return get(Opcode).Flags & M_PSEUDO_FLAG;
142  }
143  bool isTwoAddrInstr(MachineOpCode Opcode) const {
144    return get(Opcode).Flags & M_2_ADDR_FLAG;
145  }
146  bool isTerminatorInstr(unsigned Opcode) const {
147    return get(Opcode).Flags & M_TERMINATOR_FLAG;
148  }
149
150  /// Return true if the instruction is a register to register move
151  /// and leave the source and dest operands in the passed parameters.
152  virtual bool isMoveInstr(const MachineInstr& MI,
153                           unsigned& sourceReg,
154                           unsigned& destReg) const {
155    return false;
156  }
157
158  /// Insert a goto (unconditional branch) sequence to TMBB, at the
159  /// end of MBB
160  virtual void insertGoto(MachineBasicBlock& MBB,
161                          MachineBasicBlock& TMBB) const {
162    assert(0 && "Target didn't implement insertGoto!");
163  }
164
165  /// Reverses the branch condition of the MachineInstr pointed by
166  /// MI. The instruction is replaced and the new MI is returned.
167  virtual MachineBasicBlock::iterator
168  reverseBranchCondition(MachineBasicBlock::iterator MI) const {
169    assert(0 && "Target didn't implement reverseBranchCondition!");
170  }
171
172  //-------------------------------------------------------------------------
173  // Code generation support for creating individual machine instructions
174  //
175  // WARNING: These methods are Sparc specific
176  //
177  // DO NOT USE ANY OF THESE METHODS THEY ARE DEPRECATED!
178  //
179  //-------------------------------------------------------------------------
180
181  int getResultPos(MachineOpCode Opcode) const {
182    return get(Opcode).resultPos;
183  }
184  unsigned getNumDelaySlots(MachineOpCode Opcode) const {
185    return get(Opcode).numDelaySlots;
186  }
187  bool isCCInstr(MachineOpCode Opcode) const {
188    return get(Opcode).Flags & M_CC_FLAG;
189  }
190  bool isNop(MachineOpCode Opcode) const {
191    return get(Opcode).Flags & M_NOP_FLAG;
192  }
193  bool isBranch(MachineOpCode Opcode) const {
194    return get(Opcode).Flags & M_BRANCH_FLAG;
195  }
196  /// isBarrier - Returns true if the specified instruction stops control flow
197  /// from executing the instruction immediately following it.  Examples include
198  /// unconditional branches and return instructions.
199  bool isBarrier(MachineOpCode Opcode) const {
200    return get(Opcode).Flags & M_BARRIER_FLAG;
201  }
202  bool isCall(MachineOpCode Opcode) const {
203    return get(Opcode).Flags & M_CALL_FLAG;
204  }
205  bool isLoad(MachineOpCode Opcode) const {
206    return get(Opcode).Flags & M_LOAD_FLAG;
207  }
208  bool isStore(MachineOpCode Opcode) const {
209    return get(Opcode).Flags & M_STORE_FLAG;
210  }
211  bool isDummyPhiInstr(MachineOpCode Opcode) const {
212    return get(Opcode).Flags & M_DUMMY_PHI_FLAG;
213  }
214
215  virtual bool hasResultInterlock(MachineOpCode Opcode) const {
216    return true;
217  }
218
219  //
220  // Latencies for individual instructions and instruction pairs
221  //
222  virtual int minLatency(MachineOpCode Opcode) const {
223    return get(Opcode).latency;
224  }
225
226  virtual int maxLatency(MachineOpCode Opcode) const {
227    return get(Opcode).latency;
228  }
229
230  //
231  // Which operand holds an immediate constant?  Returns -1 if none
232  //
233  virtual int getImmedConstantPos(MachineOpCode Opcode) const {
234    return -1; // immediate position is machine specific, so say -1 == "none"
235  }
236
237  // Check if the specified constant fits in the immediate field
238  // of this machine instruction
239  //
240  virtual bool constantFitsInImmedField(MachineOpCode Opcode,
241					int64_t intValue) const;
242
243  // Return the largest positive constant that can be held in the IMMED field
244  // of this machine instruction.
245  // isSignExtended is set to true if the value is sign-extended before use
246  // (this is true for all immediate fields in SPARC instructions).
247  // Return 0 if the instruction has no IMMED field.
248  //
249  virtual uint64_t maxImmedConstant(MachineOpCode Opcode,
250				    bool &isSignExtended) const {
251    isSignExtended = get(Opcode).immedIsSignExtended;
252    return get(Opcode).maxImmedConst;
253  }
254};
255
256} // End llvm namespace
257
258#endif
259