#define LLVM_INSTRUCTION_H
#include "llvm/User.h"
+#include "llvm/ADT/ilist_node.h"
namespace llvm {
-struct AssemblyAnnotationWriter;
-class BinaryOperator;
+class LLVMContext;
template<typename ValueSubClass, typename ItemParentClass>
class SymbolTableListTraits;
-class Instruction : public User {
+class Instruction : public User, public ilist_node<Instruction> {
void operator=(const Instruction &); // Do not implement
Instruction(const Instruction &); // Do not implement
BasicBlock *Parent;
- Instruction *Prev, *Next; // Next and Prev links for our intrusive linked list
-
- void setNext(Instruction *N) { Next = N; }
- void setPrev(Instruction *N) { Prev = N; }
friend class SymbolTableListTraits<Instruction, BasicBlock>;
void setParent(BasicBlock *P);
// Out of line virtual method, so the vtable, etc has a home.
~Instruction();
- /// mayWriteToMemory - Return true if this instruction may modify memory.
- ///
- bool mayWriteToMemory() const;
-
/// clone() - Create a copy of 'this' instruction that is identical in all
/// ways except the following:
/// * The instruction has no parent
/// * The instruction has no name
///
- virtual Instruction *clone() const = 0;
+ virtual Instruction *clone(LLVMContext &Context) const = 0;
/// isIdenticalTo - Return true if the specified instruction is exactly
/// identical to the current one. This means that all operands match and any
/// extra information (e.g. load is volatile) agree.
- bool isIdenticalTo(Instruction *I) const;
+ bool isIdenticalTo(const Instruction *I) const;
/// This function determines if the specified instruction executes the same
/// operation as the current one. This means that the opcodes, type, operand
/// @returns true if the specified instruction is the same operation as
/// the current one.
/// @brief Determine if one instruction is the same operation as another.
- bool isSameOperationAs(Instruction *I) const;
+ bool isSameOperationAs(const Instruction *I) const;
+ /// isUsedOutsideOfBlock - Return true if there are any uses of this
+ /// instruction in blocks other than the specified block. Note that PHI nodes
+ /// are considered to evaluate their operands in the corresponding predecessor
+ /// block.
+ bool isUsedOutsideOfBlock(const BasicBlock *BB) const;
+
+
/// use_back - Specialize the methods defined in Value, as we know that an
/// instruction can only be used by other instructions.
Instruction *use_back() { return cast<Instruction>(*use_begin());}
///
void eraseFromParent();
+ /// insertBefore - Insert an unlinked instructions into a basic block
+ /// immediately before the specified instruction.
+ void insertBefore(Instruction *InsertPos);
+
+ /// insertAfter - Insert an unlinked instructions into a basic block
+ /// immediately after the specified instruction.
+ void insertAfter(Instruction *InsertPos);
+
/// moveBefore - Unlink this instruction from its current basic block and
/// insert it into the basic block that MovePos lives in, right before
/// MovePos.
return getOpcode() == Shl || getOpcode() == LShr;
}
- /// isLogicalShift - Return true if this is a logical shift left or a logical
- /// shift right.
+ /// isArithmeticShift - Return true if this is an arithmetic shift right.
inline bool isArithmeticShift() const {
return getOpcode() == AShr;
}
bool isCommutative() const { return isCommutative(getOpcode()); }
static bool isCommutative(unsigned op);
- /// isTrappingInstruction - Return true if the instruction may trap.
+ /// mayWriteToMemory - Return true if this instruction may modify memory.
+ ///
+ bool mayWriteToMemory() const;
+
+ /// mayReadFromMemory - Return true if this instruction may read memory.
+ ///
+ bool mayReadFromMemory() const;
+
+ /// mayThrow - Return true if this instruction may throw an exception.
///
- bool isTrapping() const {
- return isTrapping(getOpcode());
+ bool mayThrow() const;
+
+ /// mayHaveSideEffects - Return true if the instruction may have side effects.
+ ///
+ /// Note that this does not consider malloc and alloca to have side
+ /// effects because the newly allocated memory is completely invisible to
+ /// instructions which don't used the returned value. For cases where this
+ /// matters, isSafeToSpeculativelyExecute may be more appropriate.
+ bool mayHaveSideEffects() const {
+ return mayWriteToMemory() || mayThrow();
}
- static bool isTrapping(unsigned op);
- virtual void print(std::ostream &OS) const { print(OS, 0); }
- void print(std::ostream *OS) const { if (OS) print(*OS); }
- void print(std::ostream &OS, AssemblyAnnotationWriter *AAW) const;
+ /// isSafeToSpeculativelyExecute - Return true if the instruction does not
+ /// have any effects besides calculating the result and does not have
+ /// undefined behavior.
+ ///
+ /// This method never returns true for an instruction that returns true for
+ /// mayHaveSideEffects; however, this method also does some other checks in
+ /// addition. It checks for undefined behavior, like dividing by zero or
+ /// loading from an invalid pointer (but not for undefined results, like a
+ /// shift with a shift amount larger than the width of the result). It checks
+ /// for malloc and alloca because speculatively executing them might cause a
+ /// memory leak. It also returns false for instructions related to control
+ /// flow, specifically terminators and PHI nodes.
+ ///
+ /// This method only looks at the instruction itself and its operands, so if
+ /// this method returns true, it is safe to move the instruction as long as
+ /// the correct dominance relationships for the operands and users hold.
+ /// However, this method can return true for instructions that read memory;
+ /// for such instructions, moving them may change the resulting value.
+ bool isSafeToSpeculativelyExecute() const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Instruction *) { return true; }
#define LAST_OTHER_INST(N) OtherOpsEnd = N+1
#include "llvm/Instruction.def"
};
-
-private:
- // getNext/Prev - Return the next or previous instruction in the list. The
- // last node in the list is a terminator instruction.
- Instruction *getNext() { return Next; }
- const Instruction *getNext() const { return Next; }
- Instruction *getPrev() { return Prev; }
- const Instruction *getPrev() const { return Prev; }
};
+// Instruction* is only 4-byte aligned.
+template<>
+class PointerLikeTypeTraits<Instruction*> {
+ typedef Instruction* PT;
+public:
+ static inline void *getAsVoidPointer(PT P) { return P; }
+ static inline PT getFromVoidPointer(void *P) {
+ return static_cast<PT>(P);
+ }
+ enum { NumLowBitsAvailable = 2 };
+};
+
} // End llvm namespace
#endif
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