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_BRANCH_FLAG = 1 << 0;
48 const unsigned M_CALL_FLAG = 1 << 1;
49 const unsigned M_RET_FLAG = 1 << 2;
50 const unsigned M_BARRIER_FLAG = 1 << 3;
51 const unsigned M_DELAY_SLOT_FLAG = 1 << 4;
52 const unsigned M_LOAD_FLAG = 1 << 5;
53 const unsigned M_STORE_FLAG = 1 << 6;
55 // M_2_ADDR_FLAG - 3-addr instructions which really work like 2-addr ones.
56 const unsigned M_2_ADDR_FLAG = 1 << 7;
58 // M_CONVERTIBLE_TO_3_ADDR - This is a M_2_ADDR_FLAG instruction which can be
59 // changed into a 3-address instruction if the first two operands cannot be
60 // assigned to the same register. The target must implement the
61 // TargetInstrInfo::convertToThreeAddress method for this instruction.
62 const unsigned M_CONVERTIBLE_TO_3_ADDR = 1 << 8;
64 // This M_COMMUTABLE - is a 2- or 3-address instruction (of the form X = op Y,
65 // Z), which produces the same result if Y and Z are exchanged.
66 const unsigned M_COMMUTABLE = 1 << 9;
68 // M_TERMINATOR_FLAG - Is this instruction part of the terminator for a basic
69 // block? Typically this is things like return and branch instructions.
70 // Various passes use this to insert code into the bottom of a basic block, but
71 // before control flow occurs.
72 const unsigned M_TERMINATOR_FLAG = 1 << 10;
74 // M_USES_CUSTOM_DAG_SCHED_INSERTION - Set if this instruction requires custom
75 // insertion support when the DAG scheduler is inserting it into a machine basic
77 const unsigned M_USES_CUSTOM_DAG_SCHED_INSERTION = 1 << 11;
79 // M_VARIABLE_OPS - Set if this instruction can have a variable number of extra
80 // operands in addition to the minimum number operands specified.
81 const unsigned M_VARIABLE_OPS = 1 << 12;
83 // Machine operand flags
84 // M_LOOK_UP_PTR_REG_CLASS - Set if this operand is a pointer value and it
85 // requires a callback to look up its register class.
86 const unsigned M_LOOK_UP_PTR_REG_CLASS = 1 << 0;
88 /// TargetOperandInfo - This holds information about one operand of a machine
89 /// instruction, indicating the register class for register operands, etc.
91 class TargetOperandInfo {
93 /// RegClass - This specifies the register class enumeration of the operand
94 /// if the operand is a register. If not, this contains 0.
95 unsigned short RegClass;
97 /// Currently no other information.
101 class TargetInstrDescriptor {
103 const char * Name; // Assembly language mnemonic for the opcode.
104 unsigned numOperands; // Num of args (may be more if variable_ops).
105 InstrSchedClass schedClass; // enum identifying instr sched class
106 unsigned Flags; // flags identifying machine instr class
107 unsigned TSFlags; // Target Specific Flag values
108 const unsigned *ImplicitUses; // Registers implicitly read by this instr
109 const unsigned *ImplicitDefs; // Registers implicitly defined by this instr
110 const TargetOperandInfo *OpInfo; // 'numOperands' entries about operands.
114 //---------------------------------------------------------------------------
116 /// TargetInstrInfo - Interface to description of machine instructions
118 class TargetInstrInfo {
119 const TargetInstrDescriptor* desc; // raw array to allow static init'n
120 unsigned NumOpcodes; // number of entries in the desc array
121 unsigned numRealOpCodes; // number of non-dummy op codes
123 TargetInstrInfo(const TargetInstrInfo &); // DO NOT IMPLEMENT
124 void operator=(const TargetInstrInfo &); // DO NOT IMPLEMENT
126 TargetInstrInfo(const TargetInstrDescriptor *desc, unsigned NumOpcodes);
127 virtual ~TargetInstrInfo();
129 // Invariant opcodes: All instruction sets have these as their low opcodes.
135 unsigned getNumOpcodes() const { return NumOpcodes; }
137 /// get - Return the machine instruction descriptor that corresponds to the
138 /// specified instruction opcode.
140 const TargetInstrDescriptor& get(MachineOpCode Opcode) const {
141 assert((unsigned)Opcode < NumOpcodes);
145 const char *getName(MachineOpCode Opcode) const {
146 return get(Opcode).Name;
149 int getNumOperands(MachineOpCode Opcode) const {
150 return get(Opcode).numOperands;
153 InstrSchedClass getSchedClass(MachineOpCode Opcode) const {
154 return get(Opcode).schedClass;
157 const unsigned *getImplicitUses(MachineOpCode Opcode) const {
158 return get(Opcode).ImplicitUses;
161 const unsigned *getImplicitDefs(MachineOpCode Opcode) const {
162 return get(Opcode).ImplicitDefs;
167 // Query instruction class flags according to the machine-independent
168 // flags listed above.
170 bool isReturn(MachineOpCode Opcode) const {
171 return get(Opcode).Flags & M_RET_FLAG;
174 bool isTwoAddrInstr(MachineOpCode Opcode) const {
175 return get(Opcode).Flags & M_2_ADDR_FLAG;
177 bool isCommutableInstr(MachineOpCode Opcode) const {
178 return get(Opcode).Flags & M_COMMUTABLE;
180 bool isTerminatorInstr(unsigned Opcode) const {
181 return get(Opcode).Flags & M_TERMINATOR_FLAG;
184 bool isBranch(MachineOpCode Opcode) const {
185 return get(Opcode).Flags & M_BRANCH_FLAG;
188 /// isBarrier - Returns true if the specified instruction stops control flow
189 /// from executing the instruction immediately following it. Examples include
190 /// unconditional branches and return instructions.
191 bool isBarrier(MachineOpCode Opcode) const {
192 return get(Opcode).Flags & M_BARRIER_FLAG;
195 bool isCall(MachineOpCode Opcode) const {
196 return get(Opcode).Flags & M_CALL_FLAG;
198 bool isLoad(MachineOpCode Opcode) const {
199 return get(Opcode).Flags & M_LOAD_FLAG;
201 bool isStore(MachineOpCode Opcode) const {
202 return get(Opcode).Flags & M_STORE_FLAG;
205 /// hasDelaySlot - Returns true if the specified instruction has a delay slot
206 /// which must be filled by the code generator.
207 bool hasDelaySlot(unsigned Opcode) const {
208 return get(Opcode).Flags & M_DELAY_SLOT_FLAG;
211 /// usesCustomDAGSchedInsertionHook - Return true if this instruction requires
212 /// custom insertion support when the DAG scheduler is inserting it into a
213 /// machine basic block.
214 bool usesCustomDAGSchedInsertionHook(unsigned Opcode) const {
215 return get(Opcode).Flags & M_USES_CUSTOM_DAG_SCHED_INSERTION;
218 bool hasVariableOperands(MachineOpCode Opcode) const {
219 return get(Opcode).Flags & M_VARIABLE_OPS;
222 /// Return true if the instruction is a register to register move
223 /// and leave the source and dest operands in the passed parameters.
224 virtual bool isMoveInstr(const MachineInstr& MI,
226 unsigned& destReg) const {
230 /// isLoadFromStackSlot - If the specified machine instruction is a direct
231 /// load from a stack slot, return the virtual or physical register number of
232 /// the destination along with the FrameIndex of the loaded stack slot. If
233 /// not, return 0. This predicate must return 0 if the instruction has
234 /// any side effects other than loading from the stack slot.
235 virtual unsigned isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const{
239 /// isStoreToStackSlot - If the specified machine instruction is a direct
240 /// store to a stack slot, return the virtual or physical register number of
241 /// the source reg along with the FrameIndex of the loaded stack slot. If
242 /// not, return 0. This predicate must return 0 if the instruction has
243 /// any side effects other than storing to the stack slot.
244 virtual unsigned isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const {
248 /// convertToThreeAddress - This method must be implemented by targets that
249 /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
250 /// may be able to convert a two-address instruction into a true
251 /// three-address instruction on demand. This allows the X86 target (for
252 /// example) to convert ADD and SHL instructions into LEA instructions if they
253 /// would require register copies due to two-addressness.
255 /// This method returns a null pointer if the transformation cannot be
256 /// performed, otherwise it returns the new instruction.
258 virtual MachineInstr *convertToThreeAddress(MachineInstr *TA) const {
262 /// commuteInstruction - If a target has any instructions that are commutable,
263 /// but require converting to a different instruction or making non-trivial
264 /// changes to commute them, this method can overloaded to do this. The
265 /// default implementation of this method simply swaps the first two operands
266 /// of MI and returns it.
268 /// If a target wants to make more aggressive changes, they can construct and
269 /// return a new machine instruction. If an instruction cannot commute, it
270 /// can also return null.
272 virtual MachineInstr *commuteInstruction(MachineInstr *MI) const;
274 /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning
275 /// true if it cannot be understood (e.g. it's a switch dispatch or isn't
276 /// implemented for a target). Upon success, this returns false and returns
277 /// with the following information in various cases:
279 /// 1. If this block ends with only an unconditional branch, it sets TBB to be
280 /// the destination block.
281 /// 2. If this block ends with an conditional branch, it returns the 'true'
282 /// destination in TBB, the 'false' destination in FBB, and a list of
283 /// operands that evaluate the condition. These operands can be passed to
284 /// other TargetInstrInfo methods to create new branches.
286 /// Note that RemoveBranch and InsertBranch must be implemented to support
287 /// cases where this method returns success.
289 virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
290 MachineBasicBlock *&FBB,
291 std::vector<MachineOperand> &Cond) const {
295 /// RemoveBranch - Remove the branching code at the end of the specific MBB.
296 /// this is only invoked in cases where AnalyzeBranch returns success.
297 void RemoveBranch(MachineBasicBlock &MBB) const {
298 assert(0 && "Target didn't implement TargetInstrInfo::RemoveBranch!");
301 /// InsertBranch - Insert a branch into the end of the specified
302 /// MachineBasicBlock. This operands to this method are the same as those
303 /// returned by AnalyzeBranch. This nis invoked in cases where AnalyzeBranch
305 void InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
306 MachineBasicBlock *FBB,
307 const std::vector<MachineOperand> &Cond) const {
308 assert(0 && "Target didn't implement TargetInstrInfo::RemoveBranch!");
311 /// ReverseBranchCondition - Reverses the branch condition of the specified
312 /// condition list, returning false on success and true if it cannot be
314 virtual bool ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
318 /// insertNoop - Insert a noop into the instruction stream at the specified
320 virtual void insertNoop(MachineBasicBlock &MBB,
321 MachineBasicBlock::iterator MI) const {
322 assert(0 && "Target didn't implement insertNoop!");
326 /// getPointerRegClass - Returns a TargetRegisterClass used for pointer
328 virtual const TargetRegisterClass *getPointerRegClass() const {
329 assert(0 && "Target didn't implement getPointerRegClass!");
334 } // End llvm namespace