1 //===-- llvm/Instruction.h - Instruction class definition -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the declaration of the Instruction class, which is the
11 // base class for all of the LLVM instructions.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_INSTRUCTION_H
16 #define LLVM_INSTRUCTION_H
18 #include "llvm/User.h"
19 #include "llvm/ADT/ilist_node.h"
25 class MetadataContextImpl;
27 template<typename ValueSubClass, typename ItemParentClass>
28 class SymbolTableListTraits;
30 class Instruction : public User, public ilist_node<Instruction> {
31 void operator=(const Instruction &); // Do not implement
32 Instruction(const Instruction &); // Do not implement
36 // FIXME: Bitfieldize this.
38 friend class MetadataContextImpl;
40 friend class SymbolTableListTraits<Instruction, BasicBlock>;
41 void setParent(BasicBlock *P);
43 Instruction(const Type *Ty, unsigned iType, Use *Ops, unsigned NumOps,
44 Instruction *InsertBefore = 0);
45 Instruction(const Type *Ty, unsigned iType, Use *Ops, unsigned NumOps,
46 BasicBlock *InsertAtEnd);
47 virtual Instruction *clone_impl() const = 0;
49 // Out of line virtual method, so the vtable, etc has a home.
52 /// use_back - Specialize the methods defined in Value, as we know that an
53 /// instruction can only be used by other instructions.
54 Instruction *use_back() { return cast<Instruction>(*use_begin());}
55 const Instruction *use_back() const { return cast<Instruction>(*use_begin());}
57 inline const BasicBlock *getParent() const { return Parent; }
58 inline BasicBlock *getParent() { return Parent; }
60 /// removeFromParent - This method unlinks 'this' from the containing basic
61 /// block, but does not delete it.
63 void removeFromParent();
65 /// eraseFromParent - This method unlinks 'this' from the containing basic
66 /// block and deletes it.
68 void eraseFromParent();
70 /// insertBefore - Insert an unlinked instructions into a basic block
71 /// immediately before the specified instruction.
72 void insertBefore(Instruction *InsertPos);
74 /// insertAfter - Insert an unlinked instructions into a basic block
75 /// immediately after the specified instruction.
76 void insertAfter(Instruction *InsertPos);
78 /// moveBefore - Unlink this instruction from its current basic block and
79 /// insert it into the basic block that MovePos lives in, right before
81 void moveBefore(Instruction *MovePos);
83 //===--------------------------------------------------------------------===//
84 // Subclass classification.
85 //===--------------------------------------------------------------------===//
87 /// getOpcode() returns a member of one of the enums like Instruction::Add.
88 unsigned getOpcode() const { return getValueID() - InstructionVal; }
90 const char *getOpcodeName() const { return getOpcodeName(getOpcode()); }
91 bool isTerminator() const { return isTerminator(getOpcode()); }
92 bool isBinaryOp() const { return isBinaryOp(getOpcode()); }
93 bool isShift() { return isShift(getOpcode()); }
94 bool isCast() const { return isCast(getOpcode()); }
96 static const char* getOpcodeName(unsigned OpCode);
98 static inline bool isTerminator(unsigned OpCode) {
99 return OpCode >= TermOpsBegin && OpCode < TermOpsEnd;
102 static inline bool isBinaryOp(unsigned Opcode) {
103 return Opcode >= BinaryOpsBegin && Opcode < BinaryOpsEnd;
106 /// @brief Determine if the Opcode is one of the shift instructions.
107 static inline bool isShift(unsigned Opcode) {
108 return Opcode >= Shl && Opcode <= AShr;
111 /// isLogicalShift - Return true if this is a logical shift left or a logical
113 inline bool isLogicalShift() const {
114 return getOpcode() == Shl || getOpcode() == LShr;
117 /// isArithmeticShift - Return true if this is an arithmetic shift right.
118 inline bool isArithmeticShift() const {
119 return getOpcode() == AShr;
122 /// @brief Determine if the OpCode is one of the CastInst instructions.
123 static inline bool isCast(unsigned OpCode) {
124 return OpCode >= CastOpsBegin && OpCode < CastOpsEnd;
127 //===--------------------------------------------------------------------===//
128 // Metadata manipulation.
129 //===--------------------------------------------------------------------===//
131 /// hasMetadata() - Return true if this instruction has any metadata attached
133 bool hasMetadata() const {
137 /// getMetadata - Get the metadata of given kind attached to this Instruction.
138 /// If the metadata is not found then return null.
139 MDNode *getMetadata(unsigned KindID) const {
140 if (!hasMetadata()) return 0;
141 return getMetadataImpl(KindID);
144 /// getMetadata - Get the metadata of given kind attached to this Instruction.
145 /// If the metadata is not found then return null.
146 MDNode *getMetadata(const char *Kind) const {
147 if (!hasMetadata()) return 0;
148 return getMetadataImpl(Kind);
151 /// getAllMetadata - Get all metadata attached to this Instruction. The first
152 /// element of each pair returned is the KindID, the second element is the
153 /// metadata value. This list is returned sorted by the KindID.
154 void getAllMetadata(SmallVectorImpl<std::pair<unsigned, MDNode*> > &MDs)const{
156 getAllMetadataImpl(MDs);
159 /// setMetadata - Set the metadata of of the specified kind to the specified
160 /// node. This updates/replaces metadata if already present, or removes it if
162 void setMetadata(unsigned KindID, MDNode *Node);
163 void setMetadata(const char *Kind, MDNode *Node);
166 // These are all implemented in Metadata.cpp.
167 MDNode *getMetadataImpl(unsigned KindID) const;
168 MDNode *getMetadataImpl(const char *Kind) const;
169 void getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,MDNode*> > &)const;
171 //===--------------------------------------------------------------------===//
172 // Predicates and helper methods.
173 //===--------------------------------------------------------------------===//
176 /// isAssociative - Return true if the instruction is associative:
178 /// Associative operators satisfy: x op (y op z) === (x op y) op z
180 /// In LLVM, the Add, Mul, And, Or, and Xor operators are associative, when
181 /// not applied to floating point types.
183 bool isAssociative() const { return isAssociative(getOpcode(), getType()); }
184 static bool isAssociative(unsigned op, const Type *Ty);
186 /// isCommutative - Return true if the instruction is commutative:
188 /// Commutative operators satisfy: (x op y) === (y op x)
190 /// In LLVM, these are the associative operators, plus SetEQ and SetNE, when
191 /// applied to any type.
193 bool isCommutative() const { return isCommutative(getOpcode()); }
194 static bool isCommutative(unsigned op);
196 /// mayWriteToMemory - Return true if this instruction may modify memory.
198 bool mayWriteToMemory() const;
200 /// mayReadFromMemory - Return true if this instruction may read memory.
202 bool mayReadFromMemory() const;
204 /// mayThrow - Return true if this instruction may throw an exception.
206 bool mayThrow() const;
208 /// mayHaveSideEffects - Return true if the instruction may have side effects.
210 /// Note that this does not consider malloc and alloca to have side
211 /// effects because the newly allocated memory is completely invisible to
212 /// instructions which don't used the returned value. For cases where this
213 /// matters, isSafeToSpeculativelyExecute may be more appropriate.
214 bool mayHaveSideEffects() const {
215 return mayWriteToMemory() || mayThrow();
218 /// isSafeToSpeculativelyExecute - Return true if the instruction does not
219 /// have any effects besides calculating the result and does not have
220 /// undefined behavior.
222 /// This method never returns true for an instruction that returns true for
223 /// mayHaveSideEffects; however, this method also does some other checks in
224 /// addition. It checks for undefined behavior, like dividing by zero or
225 /// loading from an invalid pointer (but not for undefined results, like a
226 /// shift with a shift amount larger than the width of the result). It checks
227 /// for malloc and alloca because speculatively executing them might cause a
228 /// memory leak. It also returns false for instructions related to control
229 /// flow, specifically terminators and PHI nodes.
231 /// This method only looks at the instruction itself and its operands, so if
232 /// this method returns true, it is safe to move the instruction as long as
233 /// the correct dominance relationships for the operands and users hold.
234 /// However, this method can return true for instructions that read memory;
235 /// for such instructions, moving them may change the resulting value.
236 bool isSafeToSpeculativelyExecute() const;
238 /// clone() - Create a copy of 'this' instruction that is identical in all
239 /// ways except the following:
240 /// * The instruction has no parent
241 /// * The instruction has no name
243 Instruction *clone() const;
245 /// isIdenticalTo - Return true if the specified instruction is exactly
246 /// identical to the current one. This means that all operands match and any
247 /// extra information (e.g. load is volatile) agree.
248 bool isIdenticalTo(const Instruction *I) const;
250 /// isIdenticalToWhenDefined - This is like isIdenticalTo, except that it
251 /// ignores the SubclassOptionalData flags, which specify conditions
252 /// under which the instruction's result is undefined.
253 bool isIdenticalToWhenDefined(const Instruction *I) const;
255 /// This function determines if the specified instruction executes the same
256 /// operation as the current one. This means that the opcodes, type, operand
257 /// types and any other factors affecting the operation must be the same. This
258 /// is similar to isIdenticalTo except the operands themselves don't have to
260 /// @returns true if the specified instruction is the same operation as
262 /// @brief Determine if one instruction is the same operation as another.
263 bool isSameOperationAs(const Instruction *I) const;
265 /// isUsedOutsideOfBlock - Return true if there are any uses of this
266 /// instruction in blocks other than the specified block. Note that PHI nodes
267 /// are considered to evaluate their operands in the corresponding predecessor
269 bool isUsedOutsideOfBlock(const BasicBlock *BB) const;
272 /// Methods for support type inquiry through isa, cast, and dyn_cast:
273 static inline bool classof(const Instruction *) { return true; }
274 static inline bool classof(const Value *V) {
275 return V->getValueID() >= Value::InstructionVal;
278 //----------------------------------------------------------------------
279 // Exported enumerations.
281 enum TermOps { // These terminate basic blocks
282 #define FIRST_TERM_INST(N) TermOpsBegin = N,
283 #define HANDLE_TERM_INST(N, OPC, CLASS) OPC = N,
284 #define LAST_TERM_INST(N) TermOpsEnd = N+1
285 #include "llvm/Instruction.def"
289 #define FIRST_BINARY_INST(N) BinaryOpsBegin = N,
290 #define HANDLE_BINARY_INST(N, OPC, CLASS) OPC = N,
291 #define LAST_BINARY_INST(N) BinaryOpsEnd = N+1
292 #include "llvm/Instruction.def"
296 #define FIRST_MEMORY_INST(N) MemoryOpsBegin = N,
297 #define HANDLE_MEMORY_INST(N, OPC, CLASS) OPC = N,
298 #define LAST_MEMORY_INST(N) MemoryOpsEnd = N+1
299 #include "llvm/Instruction.def"
303 #define FIRST_CAST_INST(N) CastOpsBegin = N,
304 #define HANDLE_CAST_INST(N, OPC, CLASS) OPC = N,
305 #define LAST_CAST_INST(N) CastOpsEnd = N+1
306 #include "llvm/Instruction.def"
310 #define FIRST_OTHER_INST(N) OtherOpsBegin = N,
311 #define HANDLE_OTHER_INST(N, OPC, CLASS) OPC = N,
312 #define LAST_OTHER_INST(N) OtherOpsEnd = N+1
313 #include "llvm/Instruction.def"
317 // Instruction* is only 4-byte aligned.
319 class PointerLikeTypeTraits<Instruction*> {
320 typedef Instruction* PT;
322 static inline void *getAsVoidPointer(PT P) { return P; }
323 static inline PT getFromVoidPointer(void *P) {
324 return static_cast<PT>(P);
326 enum { NumLowBitsAvailable = 2 };
329 } // End llvm namespace