1 //===-- llvm/Target/TargetInstrInfo.h - Instruction Info --------*- 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 describes the target machine instructions to the code generator.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_TARGET_TARGETINSTRINFO_H
15 #define LLVM_TARGET_TARGETINSTRINFO_H
17 #include "llvm/CodeGen/MachineBasicBlock.h"
18 #include "llvm/Support/DataTypes.h"
31 class MachineCodeForInstruction;
32 class TargetRegisterClass;
34 //---------------------------------------------------------------------------
35 // Data types used to define information about a single machine instruction
36 //---------------------------------------------------------------------------
38 typedef short MachineOpCode;
39 typedef unsigned InstrSchedClass;
41 //---------------------------------------------------------------------------
42 // struct TargetInstrDescriptor:
43 // Predefined information about each machine instruction.
44 // Designed to initialized statically.
47 const unsigned M_NOP_FLAG = 1 << 0;
48 const unsigned M_BRANCH_FLAG = 1 << 1;
49 const unsigned M_CALL_FLAG = 1 << 2;
50 const unsigned M_RET_FLAG = 1 << 3;
51 const unsigned M_BARRIER_FLAG = 1 << 4;
52 const unsigned M_DELAY_SLOT_FLAG = 1 << 5;
53 const unsigned M_CC_FLAG = 1 << 6;
54 const unsigned M_LOAD_FLAG = 1 << 7;
55 const unsigned M_STORE_FLAG = 1 << 8;
57 // M_2_ADDR_FLAG - 3-addr instructions which really work like 2-addr ones.
58 const unsigned M_2_ADDR_FLAG = 1 << 9;
60 // M_CONVERTIBLE_TO_3_ADDR - This is a M_2_ADDR_FLAG instruction which can be
61 // changed into a 3-address instruction if the first two operands cannot be
62 // assigned to the same register. The target must implement the
63 // TargetInstrInfo::convertToThreeAddress method for this instruction.
64 const unsigned M_CONVERTIBLE_TO_3_ADDR = 1 << 10;
66 // This M_COMMUTABLE - is a 2- or 3-address instruction (of the form X = op Y,
67 // Z), which produces the same result if Y and Z are exchanged.
68 const unsigned M_COMMUTABLE = 1 << 11;
70 // M_TERMINATOR_FLAG - Is this instruction part of the terminator for a basic
71 // block? Typically this is things like return and branch instructions.
72 // Various passes use this to insert code into the bottom of a basic block, but
73 // before control flow occurs.
74 const unsigned M_TERMINATOR_FLAG = 1 << 12;
76 // M_USES_CUSTOM_DAG_SCHED_INSERTION - Set if this instruction requires custom
77 // insertion support when the DAG scheduler is inserting it into a machine basic
79 const unsigned M_USES_CUSTOM_DAG_SCHED_INSERTION = 1 << 13;
81 /// TargetOperandInfo - This holds information about one operand of a machine
82 /// instruction, indicating the register class for register operands, etc.
84 class TargetOperandInfo {
86 /// RegClass - This specifies the register class of the operand if the
87 /// operand is a register. If not, this contains null.
88 const TargetRegisterClass *RegClass;
90 /// Currently no other information.
94 class TargetInstrDescriptor {
96 const char * Name; // Assembly language mnemonic for the opcode.
97 int numOperands; // Number of args; -1 if variable #args
98 int resultPos; // Position of the result; -1 if no result
99 unsigned maxImmedConst; // Largest +ve constant in IMMED field or 0.
100 bool immedIsSignExtended; // Is IMMED field sign-extended? If so,
101 // smallest -ve value is -(maxImmedConst+1).
102 unsigned numDelaySlots; // Number of delay slots after instruction
103 unsigned latency; // Latency in machine cycles
104 InstrSchedClass schedClass; // enum identifying instr sched class
105 unsigned Flags; // flags identifying machine instr class
106 unsigned TSFlags; // Target Specific Flag values
107 const unsigned *ImplicitUses; // Registers implicitly read by this instr
108 const unsigned *ImplicitDefs; // Registers implicitly defined by this instr
109 const TargetOperandInfo *OpInfo; // 'numOperands' entries about operands.
113 //---------------------------------------------------------------------------
115 /// TargetInstrInfo - Interface to description of machine instructions
117 class TargetInstrInfo {
118 const TargetInstrDescriptor* desc; // raw array to allow static init'n
119 unsigned NumOpcodes; // number of entries in the desc array
120 unsigned numRealOpCodes; // number of non-dummy op codes
122 TargetInstrInfo(const TargetInstrInfo &); // DO NOT IMPLEMENT
123 void operator=(const TargetInstrInfo &); // DO NOT IMPLEMENT
125 TargetInstrInfo(const TargetInstrDescriptor *desc, unsigned NumOpcodes);
126 virtual ~TargetInstrInfo();
128 // Invariant: All instruction sets use opcode #0 as the PHI instruction
131 unsigned getNumOpcodes() const { return NumOpcodes; }
133 /// get - Return the machine instruction descriptor that corresponds to the
134 /// specified instruction opcode.
136 const TargetInstrDescriptor& get(MachineOpCode Opcode) const {
137 assert((unsigned)Opcode < NumOpcodes);
141 const char *getName(MachineOpCode Opcode) const {
142 return get(Opcode).Name;
145 int getNumOperands(MachineOpCode Opcode) const {
146 return get(Opcode).numOperands;
149 InstrSchedClass getSchedClass(MachineOpCode Opcode) const {
150 return get(Opcode).schedClass;
153 const unsigned *getImplicitUses(MachineOpCode Opcode) const {
154 return get(Opcode).ImplicitUses;
157 const unsigned *getImplicitDefs(MachineOpCode Opcode) const {
158 return get(Opcode).ImplicitDefs;
163 // Query instruction class flags according to the machine-independent
164 // flags listed above.
166 bool isReturn(MachineOpCode Opcode) const {
167 return get(Opcode).Flags & M_RET_FLAG;
170 bool isTwoAddrInstr(MachineOpCode Opcode) const {
171 return get(Opcode).Flags & M_2_ADDR_FLAG;
173 bool isTerminatorInstr(unsigned Opcode) const {
174 return get(Opcode).Flags & M_TERMINATOR_FLAG;
177 bool isBranch(MachineOpCode Opcode) const {
178 return get(Opcode).Flags & M_BRANCH_FLAG;
181 /// isBarrier - Returns true if the specified instruction stops control flow
182 /// from executing the instruction immediately following it. Examples include
183 /// unconditional branches and return instructions.
184 bool isBarrier(MachineOpCode Opcode) const {
185 return get(Opcode).Flags & M_BARRIER_FLAG;
188 bool isCall(MachineOpCode Opcode) const {
189 return get(Opcode).Flags & M_CALL_FLAG;
191 bool isLoad(MachineOpCode Opcode) const {
192 return get(Opcode).Flags & M_LOAD_FLAG;
194 bool isStore(MachineOpCode Opcode) const {
195 return get(Opcode).Flags & M_STORE_FLAG;
198 /// usesCustomDAGSchedInsertionHook - Return true if this instruction requires
199 /// custom insertion support when the DAG scheduler is inserting it into a
200 /// machine basic block.
201 bool usesCustomDAGSchedInsertionHook(unsigned Opcode) const {
202 return get(Opcode).Flags & M_USES_CUSTOM_DAG_SCHED_INSERTION;
205 /// Return true if the instruction is a register to register move
206 /// and leave the source and dest operands in the passed parameters.
207 virtual bool isMoveInstr(const MachineInstr& MI,
209 unsigned& destReg) const {
213 /// convertToThreeAddress - This method must be implemented by targets that
214 /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
215 /// may be able to convert a two-address instruction into a true
216 /// three-address instruction on demand. This allows the X86 target (for
217 /// example) to convert ADD and SHL instructions into LEA instructions if they
218 /// would require register copies due to two-addressness.
220 /// This method returns a null pointer if the transformation cannot be
221 /// performed, otherwise it returns the new instruction.
223 virtual MachineInstr *convertToThreeAddress(MachineInstr *TA) const {
227 /// commuteInstruction - If a target has any instructions that are commutable,
228 /// but require converting to a different instruction or making non-trivial
229 /// changes to commute them, this method can overloaded to do this. The
230 /// default implementation of this method simply swaps the first two operands
231 /// of MI and returns it.
233 /// If a target wants to make more aggressive changes, they can construct and
234 /// return a new machine instruction. If an instruction cannot commute, it
235 /// can also return null.
237 virtual MachineInstr *commuteInstruction(MachineInstr *MI) const;
239 /// Insert a goto (unconditional branch) sequence to TMBB, at the
241 virtual void insertGoto(MachineBasicBlock& MBB,
242 MachineBasicBlock& TMBB) const {
243 assert(0 && "Target didn't implement insertGoto!");
246 /// Reverses the branch condition of the MachineInstr pointed by
247 /// MI. The instruction is replaced and the new MI is returned.
248 virtual MachineBasicBlock::iterator
249 reverseBranchCondition(MachineBasicBlock::iterator MI) const {
250 assert(0 && "Target didn't implement reverseBranchCondition!");
256 //-------------------------------------------------------------------------
257 // Code generation support for creating individual machine instructions
259 // WARNING: These methods are Sparc specific
261 // DO NOT USE ANY OF THESE METHODS THEY ARE DEPRECATED!
263 //-------------------------------------------------------------------------
265 unsigned getNumDelaySlots(MachineOpCode Opcode) const {
266 return get(Opcode).numDelaySlots;
268 bool isCCInstr(MachineOpCode Opcode) const {
269 return get(Opcode).Flags & M_CC_FLAG;
271 bool isNop(MachineOpCode Opcode) const {
272 return get(Opcode).Flags & M_NOP_FLAG;
275 /// hasDelaySlot - Returns true if the specified instruction has a delay slot
276 /// which must be filled by the code generator.
277 bool hasDelaySlot(unsigned Opcode) const {
278 return get(Opcode).Flags & M_DELAY_SLOT_FLAG;
281 virtual bool hasResultInterlock(MachineOpCode Opcode) const {
286 // Latencies for individual instructions and instruction pairs
288 virtual int minLatency(MachineOpCode Opcode) const {
289 return get(Opcode).latency;
292 virtual int maxLatency(MachineOpCode Opcode) const {
293 return get(Opcode).latency;
297 // Which operand holds an immediate constant? Returns -1 if none
299 virtual int getImmedConstantPos(MachineOpCode Opcode) const {
300 return -1; // immediate position is machine specific, so say -1 == "none"
303 // Check if the specified constant fits in the immediate field
304 // of this machine instruction
306 virtual bool constantFitsInImmedField(MachineOpCode Opcode,
307 int64_t intValue) const;
309 // Return the largest positive constant that can be held in the IMMED field
310 // of this machine instruction.
311 // isSignExtended is set to true if the value is sign-extended before use
312 // (this is true for all immediate fields in SPARC instructions).
313 // Return 0 if the instruction has no IMMED field.
315 virtual uint64_t maxImmedConstant(MachineOpCode Opcode,
316 bool &isSignExtended) const {
317 isSignExtended = get(Opcode).immedIsSignExtended;
318 return get(Opcode).maxImmedConst;
322 } // End llvm namespace