aboutsummaryrefslogtreecommitdiff
path: root/lib/Target/Mips/MipsMachineFunction.h
blob: 325619313dee451f5c2346583ee97be2c8196c1e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
//===-- MipsMachineFunctionInfo.h - Private data used for Mips ----*- C++ -*-=//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the Mips specific subclass of MachineFunctionInfo.
//
//===----------------------------------------------------------------------===//

#ifndef MIPS_MACHINE_FUNCTION_INFO_H
#define MIPS_MACHINE_FUNCTION_INFO_H

#include <utility>
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/VectorExtras.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"

namespace llvm {

/// MipsFunctionInfo - This class is derived from MachineFunction private
/// Mips target-specific information for each MachineFunction.
class MipsFunctionInfo : public MachineFunctionInfo {

private:
  /// Holds for each function where on the stack the Frame Pointer must be
  /// saved. This is used on Prologue and Epilogue to emit FP save/restore
  int FPStackOffset;

  /// Holds for each function where on the stack the Return Address must be
  /// saved. This is used on Prologue and Epilogue to emit RA save/restore
  int RAStackOffset;

  /// At each function entry, two special bitmask directives must be emitted
  /// to help debugging, for CPU and FPU callee saved registers. Both need
  /// the negative offset from the final stack size and its higher registers
  /// location on the stack.
  int CPUTopSavedRegOff;
  int FPUTopSavedRegOff;

  /// MipsFIHolder - Holds a FrameIndex and it's Stack Pointer Offset
  struct MipsFIHolder {

    int FI;
    int SPOffset;

    MipsFIHolder(int FrameIndex, int StackPointerOffset)
      : FI(FrameIndex), SPOffset(StackPointerOffset) {}
  };

  /// When PIC is used the GP must be saved on the stack on the function
  /// prologue and must be reloaded from this stack location after every
  /// call. A reference to its stack location and frame index must be kept
  /// to be used on emitPrologue and processFunctionBeforeFrameFinalized.
  MipsFIHolder GPHolder;

  /// On LowerFormalArguments the stack size is unknown, so the Stack
  /// Pointer Offset calculation of "not in register arguments" must be
  /// postponed to emitPrologue.
  SmallVector<MipsFIHolder, 16> FnLoadArgs;
  bool HasLoadArgs;

  // When VarArgs, we must write registers back to caller stack, preserving
  // on register arguments. Since the stack size is unknown on
  // LowerFormalArguments, the Stack Pointer Offset calculation must be
  // postponed to emitPrologue.
  SmallVector<MipsFIHolder, 4> FnStoreVarArgs;
  bool HasStoreVarArgs;

  /// SRetReturnReg - Some subtargets require that sret lowering includes
  /// returning the value of the returned struct in a register. This field
  /// holds the virtual register into which the sret argument is passed.
  unsigned SRetReturnReg;

  /// GlobalBaseReg - keeps track of the virtual register initialized for
  /// use as the global base register. This is used for PIC in some PIC
  /// relocation models.
  unsigned GlobalBaseReg;

  /// VarArgsFrameIndex - FrameIndex for start of varargs area.
  int VarArgsFrameIndex;

  // Range of frame object indices.
  // InArgFIRange: Range of indices of all frame objects created during call to
  //               LowerFormalArguments.
  // OutArgFIRange: Range of indices of all frame objects created during call to
  //                LowerCall except for the frame object for restoring $gp. 
  std::pair<int, int> InArgFIRange, OutArgFIRange;
  int GPFI; // Index of the frame object for restoring $gp 
  bool HasCall; // True if function has a function call.
public:
  MipsFunctionInfo(MachineFunction& MF)
  : FPStackOffset(0), RAStackOffset(0), CPUTopSavedRegOff(0),
    FPUTopSavedRegOff(0), GPHolder(-1,-1), HasLoadArgs(false),
    HasStoreVarArgs(false), SRetReturnReg(0), GlobalBaseReg(0),
    VarArgsFrameIndex(0), InArgFIRange(std::make_pair(-1, 0)),
    OutArgFIRange(std::make_pair(-1, 0)), GPFI(0), HasCall(false)
  {}

  int getFPStackOffset() const { return FPStackOffset; }
  void setFPStackOffset(int Off) { FPStackOffset = Off; }

  int getRAStackOffset() const { return RAStackOffset; }
  void setRAStackOffset(int Off) { RAStackOffset = Off; }

  int getCPUTopSavedRegOff() const { return CPUTopSavedRegOff; }
  void setCPUTopSavedRegOff(int Off) { CPUTopSavedRegOff = Off; }

  int getFPUTopSavedRegOff() const { return FPUTopSavedRegOff; }
  void setFPUTopSavedRegOff(int Off) { FPUTopSavedRegOff = Off; }

  bool isInArgFI(int FI) const {
    return FI <= InArgFIRange.first && FI >= InArgFIRange.second;
  }
  void setLastInArgFI(int FI) { InArgFIRange.second = FI; }

  bool isOutArgFI(int FI) const { 
    return FI <= OutArgFIRange.first && FI >= OutArgFIRange.second;
  }
  void extendOutArgFIRange(int FirstFI, int LastFI) {
    if (!OutArgFIRange.second)
      // this must be the first time this function was called.
      OutArgFIRange.first = FirstFI;
    OutArgFIRange.second = LastFI;
  }

  int getGPStackOffset() const { return GPHolder.SPOffset; }
  int getGPFI() const { return GPHolder.FI; }
  void setGPStackOffset(int Off) { GPHolder.SPOffset = Off; }
  void setGPFI(int FI) { GPHolder.FI = FI; }
  bool needGPSaveRestore() const { return GPHolder.SPOffset != -1; }
  bool isGPFI(int FI) const { return GPFI && GPFI == FI; }

  bool hasLoadArgs() const { return HasLoadArgs; }
  bool hasStoreVarArgs() const { return HasStoreVarArgs; }

  void recordLoadArgsFI(int FI, int SPOffset) {
    if (!HasLoadArgs) HasLoadArgs=true;
    FnLoadArgs.push_back(MipsFIHolder(FI, SPOffset));
  }
  void recordStoreVarArgsFI(int FI, int SPOffset) {
    if (!HasStoreVarArgs) HasStoreVarArgs=true;
    FnStoreVarArgs.push_back(MipsFIHolder(FI, SPOffset));
  }

  void adjustLoadArgsFI(MachineFrameInfo *MFI) const {
    if (!hasLoadArgs()) return;
    for (unsigned i = 0, e = FnLoadArgs.size(); i != e; ++i)
      MFI->setObjectOffset( FnLoadArgs[i].FI, FnLoadArgs[i].SPOffset );
  }
  void adjustStoreVarArgsFI(MachineFrameInfo *MFI) const {
    if (!hasStoreVarArgs()) return;
    for (unsigned i = 0, e = FnStoreVarArgs.size(); i != e; ++i)
      MFI->setObjectOffset( FnStoreVarArgs[i].FI, FnStoreVarArgs[i].SPOffset );
  }

  unsigned getSRetReturnReg() const { return SRetReturnReg; }
  void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }

  unsigned getGlobalBaseReg() const { return GlobalBaseReg; }
  void setGlobalBaseReg(unsigned Reg) { GlobalBaseReg = Reg; }

  int getVarArgsFrameIndex() const { return VarArgsFrameIndex; }
  void setVarArgsFrameIndex(int Index) { VarArgsFrameIndex = Index; }

  bool hasCall() const { return HasCall; }
  void setHasCall() { HasCall = true; }
};

} // end of namespace llvm

#endif // MIPS_MACHINE_FUNCTION_INFO_H