X86InstrInfo.h revision 41e431ba045eb317ebf0ec45b563a5d96c212f5c 
1//===- X86InstrInfo.h - X86 Instruction Information ------------*- 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 contains the X86 implementation of the TargetInstrInfo class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef X86INSTRUCTIONINFO_H
15#define X86INSTRUCTIONINFO_H
16
17#include "llvm/Target/TargetInstrInfo.h"
18#include "X86RegisterInfo.h"
19
20namespace llvm {
21
22/// X86II - This namespace holds all of the target specific flags that
23/// instruction info tracks.
24///
25namespace X86II {
26  enum {
27    //===------------------------------------------------------------------===//
28    // Instruction types.  These are the standard/most common forms for X86
29    // instructions.
30    //
31
32    // PseudoFrm - This represents an instruction that is a pseudo instruction
33    // or one that has not been implemented yet.  It is illegal to code generate
34    // it, but tolerated for intermediate implementation stages.
35    Pseudo         = 0,
36
37    /// Raw - This form is for instructions that don't have any operands, so
38    /// they are just a fixed opcode value, like 'leave'.
39    RawFrm         = 1,
40
41    /// AddRegFrm - This form is used for instructions like 'push r32' that have
42    /// their one register operand added to their opcode.
43    AddRegFrm      = 2,
44
45    /// MRMDestReg - This form is used for instructions that use the Mod/RM byte
46    /// to specify a destination, which in this case is a register.
47    ///
48    MRMDestReg     = 3,
49
50    /// MRMDestMem - This form is used for instructions that use the Mod/RM byte
51    /// to specify a destination, which in this case is memory.
52    ///
53    MRMDestMem     = 4,
54
55    /// MRMSrcReg - This form is used for instructions that use the Mod/RM byte
56    /// to specify a source, which in this case is a register.
57    ///
58    MRMSrcReg      = 5,
59
60    /// MRMSrcMem - This form is used for instructions that use the Mod/RM byte
61    /// to specify a source, which in this case is memory.
62    ///
63    MRMSrcMem      = 6,
64
65    /// MRM[0-7][rm] - These forms are used to represent instructions that use
66    /// a Mod/RM byte, and use the middle field to hold extended opcode
67    /// information.  In the intel manual these are represented as /0, /1, ...
68    ///
69
70    // First, instructions that operate on a register r/m operand...
71    MRM0r = 16,  MRM1r = 17,  MRM2r = 18,  MRM3r = 19, // Format /0 /1 /2 /3
72    MRM4r = 20,  MRM5r = 21,  MRM6r = 22,  MRM7r = 23, // Format /4 /5 /6 /7
73
74    // Next, instructions that operate on a memory r/m operand...
75    MRM0m = 24,  MRM1m = 25,  MRM2m = 26,  MRM3m = 27, // Format /0 /1 /2 /3
76    MRM4m = 28,  MRM5m = 29,  MRM6m = 30,  MRM7m = 31, // Format /4 /5 /6 /7
77
78    FormMask       = 31,
79
80    //===------------------------------------------------------------------===//
81    // Actual flags...
82
83    // OpSize - Set if this instruction requires an operand size prefix (0x66),
84    // which most often indicates that the instruction operates on 16 bit data
85    // instead of 32 bit data.
86    OpSize      = 1 << 5,
87
88    // Op0Mask - There are several prefix bytes that are used to form two byte
89    // opcodes.  These are currently 0x0F, 0xF3, and 0xD8-0xDF.  This mask is
90    // used to obtain the setting of this field.  If no bits in this field is
91    // set, there is no prefix byte for obtaining a multibyte opcode.
92    //
93    Op0Shift    = 6,
94    Op0Mask     = 0xF << Op0Shift,
95
96    // TB - TwoByte - Set if this instruction has a two byte opcode, which
97    // starts with a 0x0F byte before the real opcode.
98    TB          = 1 << Op0Shift,
99
100    // REP - The 0xF3 prefix byte indicating repetition of the following
101    // instruction.
102    REP         = 2 << Op0Shift,
103
104    // D8-DF - These escape opcodes are used by the floating point unit.  These
105    // values must remain sequential.
106    D8 = 3 << Op0Shift,   D9 = 4 << Op0Shift,
107    DA = 5 << Op0Shift,   DB = 6 << Op0Shift,
108    DC = 7 << Op0Shift,   DD = 8 << Op0Shift,
109    DE = 9 << Op0Shift,   DF = 10 << Op0Shift,
110
111    //===------------------------------------------------------------------===//
112    // This two-bit field describes the size of an immediate operand.  Zero is
113    // unused so that we can tell if we forgot to set a value.
114    ImmShift = 10,
115    ImmMask  = 7 << ImmShift,
116    Imm8     = 1 << ImmShift,
117    Imm16    = 2 << ImmShift,
118    Imm32    = 3 << ImmShift,
119
120    //===------------------------------------------------------------------===//
121    // FP Instruction Classification...  Zero is non-fp instruction.
122
123    // FPTypeMask - Mask for all of the FP types...
124    FPTypeShift = 12,
125    FPTypeMask  = 7 << FPTypeShift,
126
127    // NotFP - The default, set for instructions that do not use FP registers.
128    NotFP      = 0 << FPTypeShift,
129
130    // ZeroArgFP - 0 arg FP instruction which implicitly pushes ST(0), f.e. fld0
131    ZeroArgFP  = 1 << FPTypeShift,
132
133    // OneArgFP - 1 arg FP instructions which implicitly read ST(0), such as fst
134    OneArgFP   = 2 << FPTypeShift,
135
136    // OneArgFPRW - 1 arg FP instruction which implicitly read ST(0) and write a
137    // result back to ST(0).  For example, fcos, fsqrt, etc.
138    //
139    OneArgFPRW = 3 << FPTypeShift,
140
141    // TwoArgFP - 2 arg FP instructions which implicitly read ST(0), and an
142    // explicit argument, storing the result to either ST(0) or the implicit
143    // argument.  For example: fadd, fsub, fmul, etc...
144    TwoArgFP   = 4 << FPTypeShift,
145
146    // CompareFP - 2 arg FP instructions which implicitly read ST(0) and an
147    // explicit argument, but have no destination.  Example: fucom, fucomi, ...
148    CompareFP  = 5 << FPTypeShift,
149
150    // CondMovFP - "2 operand" floating point conditional move instructions.
151    CondMovFP  = 6 << FPTypeShift,
152
153    // SpecialFP - Special instruction forms.  Dispatch by opcode explicitly.
154    SpecialFP  = 7 << FPTypeShift,
155
156    // Bit 15 is unused.
157    OpcodeShift   = 16,
158    OpcodeMask    = 0xFF << OpcodeShift,
159    // Bits 24 -> 31 are unused
160  };
161}
162
163class X86InstrInfo : public TargetInstrInfo {
164  const X86RegisterInfo RI;
165public:
166  X86InstrInfo();
167
168  /// getRegisterInfo - TargetInstrInfo is a superset of MRegister info.  As
169  /// such, whenever a client has an instance of instruction info, it should
170  /// always be able to get register info as well (through this method).
171  ///
172  virtual const MRegisterInfo &getRegisterInfo() const { return RI; }
173
174  //
175  // Return true if the instruction is a register to register move and
176  // leave the source and dest operands in the passed parameters.
177  //
178  virtual bool isMoveInstr(const MachineInstr& MI,
179                           unsigned& sourceReg,
180                           unsigned& destReg) const;
181
182  /// convertToThreeAddress - This method must be implemented by targets that
183  /// set the M_CONVERTIBLE_TO_3_ADDR flag.  When this flag is set, the target
184  /// may be able to convert a two-address instruction into a true
185  /// three-address instruction on demand.  This allows the X86 target (for
186  /// example) to convert ADD and SHL instructions into LEA instructions if they
187  /// would require register copies due to two-addressness.
188  ///
189  /// This method returns a null pointer if the transformation cannot be
190  /// performed, otherwise it returns the new instruction.
191  ///
192  virtual MachineInstr *convertToThreeAddress(MachineInstr *TA) const;
193
194  /// commuteInstruction - We have a few instructions that must be hacked on to
195  /// commute them.
196  ///
197  virtual MachineInstr *commuteInstruction(MachineInstr *MI) const;
198
199
200  /// Insert a goto (unconditional branch) sequence to TMBB, at the
201  /// end of MBB
202  virtual void insertGoto(MachineBasicBlock& MBB,
203                          MachineBasicBlock& TMBB) const;
204
205  /// Reverses the branch condition of the MachineInstr pointed by
206  /// MI. The instruction is replaced and the new MI is returned.
207  virtual MachineBasicBlock::iterator
208  reverseBranchCondition(MachineBasicBlock::iterator MI) const;
209
210  // getBaseOpcodeFor - This function returns the "base" X86 opcode for the
211  // specified opcode number.
212  //
213  unsigned char getBaseOpcodeFor(unsigned Opcode) const {
214    return get(Opcode).TSFlags >> X86II::OpcodeShift;
215  }
216};
217
218} // End llvm namespace
219
220#endif
221