1 //===-- llvm/MC/MachineLocation.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 // The MachineLocation class is used to represent a simple location in a machine
10 // frame.  Locations will be one of two forms; a register or an address formed
11 // from a base address plus an offset.  Register indirection can be specified by
12 // using an offset of zero.
13 //
14 // The MachineMove class is used to represent abstract move operations in the
15 // prolog/epilog of a compiled function.  A collection of these objects can be
16 // used by a debug consumer to track the location of values when unwinding stack
17 // frames.
18 //===----------------------------------------------------------------------===//
19 
20 
21 #ifndef LLVM_MC_MACHINELOCATION_H
22 #define LLVM_MC_MACHINELOCATION_H
23 
24 namespace llvm {
25   class MCSymbol;
26 
27 class MachineLocation {
28 private:
29   bool IsRegister;                      // True if location is a register.
30   unsigned Register;                    // gcc/gdb register number.
31   int Offset;                           // Displacement if not register.
32 public:
33   enum {
34     // The target register number for an abstract frame pointer. The value is
35     // an arbitrary value that doesn't collide with any real target register.
36     VirtualFP = ~0U
37   };
38   MachineLocation()
39     : IsRegister(false), Register(0), Offset(0) {}
40   explicit MachineLocation(unsigned R)
41     : IsRegister(true), Register(R), Offset(0) {}
42   MachineLocation(unsigned R, int O)
43     : IsRegister(false), Register(R), Offset(O) {}
44 
45   bool operator==(const MachineLocation &Other) const {
46       return IsRegister == Other.IsRegister && Register == Other.Register &&
47         Offset == Other.Offset;
48   }
49 
50   // Accessors
51   bool isReg()           const { return IsRegister; }
52   unsigned getReg()      const { return Register; }
53   int getOffset()        const { return Offset; }
54   void setIsRegister(bool Is)  { IsRegister = Is; }
55   void setRegister(unsigned R) { Register = R; }
56   void setOffset(int O)        { Offset = O; }
57   void set(unsigned R) {
58     IsRegister = true;
59     Register = R;
60     Offset = 0;
61   }
62   void set(unsigned R, int O) {
63     IsRegister = false;
64     Register = R;
65     Offset = O;
66   }
67 
68 #ifndef NDEBUG
69   void dump();
70 #endif
71 };
72 
73 /// MachineMove - This class represents the save or restore of a callee saved
74 /// register that exception or debug info needs to know about.
75 class MachineMove {
76 private:
77   /// Label - Symbol for post-instruction address when result of move takes
78   /// effect.
79   MCSymbol *Label;
80 
81   // Move to & from location.
82   MachineLocation Destination, Source;
83 public:
84   MachineMove() : Label(0) {}
85 
86   MachineMove(MCSymbol *label, const MachineLocation &D,
87               const MachineLocation &S)
88   : Label(label), Destination(D), Source(S) {}
89 
90   // Accessors
91   MCSymbol *getLabel()                    const { return Label; }
92   const MachineLocation &getDestination() const { return Destination; }
93   const MachineLocation &getSource()      const { return Source; }
94 };
95 
96 } // End llvm namespace
97 
98 #endif
99