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      1 //===-- llvm/CodeGen/PseudoSourceValue.h ------------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file contains the declaration of the PseudoSourceValue class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CODEGEN_PSEUDOSOURCEVALUE_H
     15 #define LLVM_CODEGEN_PSEUDOSOURCEVALUE_H
     16 
     17 #include "llvm/Value.h"
     18 
     19 namespace llvm {
     20   class MachineFrameInfo;
     21   class raw_ostream;
     22 
     23   /// PseudoSourceValue - Special value supplied for machine level alias
     24   /// analysis. It indicates that a memory access references the functions
     25   /// stack frame (e.g., a spill slot), below the stack frame (e.g., argument
     26   /// space), or constant pool.
     27   class PseudoSourceValue : public Value {
     28   private:
     29     /// printCustom - Implement printing for PseudoSourceValue. This is called
     30     /// from Value::print or Value's operator<<.
     31     ///
     32     virtual void printCustom(raw_ostream &O) const;
     33 
     34   public:
     35     explicit PseudoSourceValue(enum ValueTy Subclass = PseudoSourceValueVal);
     36 
     37     /// isConstant - Test whether the memory pointed to by this
     38     /// PseudoSourceValue has a constant value.
     39     ///
     40     virtual bool isConstant(const MachineFrameInfo *) const;
     41 
     42     /// isAliased - Test whether the memory pointed to by this
     43     /// PseudoSourceValue may also be pointed to by an LLVM IR Value.
     44     virtual bool isAliased(const MachineFrameInfo *) const;
     45 
     46     /// mayAlias - Return true if the memory pointed to by this
     47     /// PseudoSourceValue can ever alias a LLVM IR Value.
     48     virtual bool mayAlias(const MachineFrameInfo *) const;
     49 
     50     /// classof - Methods for support type inquiry through isa, cast, and
     51     /// dyn_cast:
     52     ///
     53     static inline bool classof(const PseudoSourceValue *) { return true; }
     54     static inline bool classof(const Value *V) {
     55       return V->getValueID() == PseudoSourceValueVal ||
     56              V->getValueID() == FixedStackPseudoSourceValueVal;
     57     }
     58 
     59     /// A pseudo source value referencing a fixed stack frame entry,
     60     /// e.g., a spill slot.
     61     static const PseudoSourceValue *getFixedStack(int FI);
     62 
     63     /// A pseudo source value referencing the area below the stack frame of
     64     /// a function, e.g., the argument space.
     65     static const PseudoSourceValue *getStack();
     66 
     67     /// A pseudo source value referencing the global offset table
     68     /// (or something the like).
     69     static const PseudoSourceValue *getGOT();
     70 
     71     /// A pseudo source value referencing the constant pool. Since constant
     72     /// pools are constant, this doesn't need to identify a specific constant
     73     /// pool entry.
     74     static const PseudoSourceValue *getConstantPool();
     75 
     76     /// A pseudo source value referencing a jump table. Since jump tables are
     77     /// constant, this doesn't need to identify a specific jump table.
     78     static const PseudoSourceValue *getJumpTable();
     79   };
     80 
     81   /// FixedStackPseudoSourceValue - A specialized PseudoSourceValue
     82   /// for holding FixedStack values, which must include a frame
     83   /// index.
     84   class FixedStackPseudoSourceValue : public PseudoSourceValue {
     85     const int FI;
     86   public:
     87     explicit FixedStackPseudoSourceValue(int fi) :
     88         PseudoSourceValue(FixedStackPseudoSourceValueVal), FI(fi) {}
     89 
     90     /// classof - Methods for support type inquiry through isa, cast, and
     91     /// dyn_cast:
     92     ///
     93     static inline bool classof(const FixedStackPseudoSourceValue *) {
     94       return true;
     95     }
     96     static inline bool classof(const Value *V) {
     97       return V->getValueID() == FixedStackPseudoSourceValueVal;
     98     }
     99 
    100     virtual bool isConstant(const MachineFrameInfo *MFI) const;
    101 
    102     virtual bool isAliased(const MachineFrameInfo *MFI) const;
    103 
    104     virtual bool mayAlias(const MachineFrameInfo *) const;
    105 
    106     virtual void printCustom(raw_ostream &OS) const;
    107 
    108     int getFrameIndex() const { return FI; }
    109   };
    110 } // End llvm namespace
    111 
    112 #endif
    113