1// Copyright 2012 the V8 project authors. All rights reserved.
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3// modification, are permitted provided that the following conditions are
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26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28#ifndef V8_ARM_FRAMES_ARM_H_
29#define V8_ARM_FRAMES_ARM_H_
30
31namespace v8 {
32namespace internal {
33
34
35// The ARM ABI does not specify the usage of register r9, which may be reserved
36// as the static base or thread register on some platforms, in which case we
37// leave it alone. Adjust the value of kR9Available accordingly:
38const int kR9Available = 1;  // 1 if available to us, 0 if reserved
39
40
41// Register list in load/store instructions
42// Note that the bit values must match those used in actual instruction encoding
43const int kNumRegs = 16;
44
45
46// Caller-saved/arguments registers
47const RegList kJSCallerSaved =
48  1 << 0 |  // r0 a1
49  1 << 1 |  // r1 a2
50  1 << 2 |  // r2 a3
51  1 << 3;   // r3 a4
52
53const int kNumJSCallerSaved = 4;
54
55typedef Object* JSCallerSavedBuffer[kNumJSCallerSaved];
56
57// Return the code of the n-th caller-saved register available to JavaScript
58// e.g. JSCallerSavedReg(0) returns r0.code() == 0
59int JSCallerSavedCode(int n);
60
61
62// Callee-saved registers preserved when switching from C to JavaScript
63const RegList kCalleeSaved =
64  1 <<  4 |  //  r4 v1
65  1 <<  5 |  //  r5 v2
66  1 <<  6 |  //  r6 v3
67  1 <<  7 |  //  r7 v4
68  1 <<  8 |  //  r8 v5 (cp in JavaScript code)
69  kR9Available <<  9 |  //  r9 v6
70  1 << 10 |  // r10 v7
71  1 << 11;   // r11 v8 (fp in JavaScript code)
72
73// When calling into C++ (only for C++ calls that can't cause a GC).
74// The call code will take care of lr, fp, etc.
75const RegList kCallerSaved =
76  1 <<  0 |  // r0
77  1 <<  1 |  // r1
78  1 <<  2 |  // r2
79  1 <<  3 |  // r3
80  1 <<  9;   // r9
81
82
83const int kNumCalleeSaved = 7 + kR9Available;
84
85// Double registers d8 to d15 are callee-saved.
86const int kNumDoubleCalleeSaved = 8;
87
88
89// Number of registers for which space is reserved in safepoints. Must be a
90// multiple of 8.
91// TODO(regis): Only 8 registers may actually be sufficient. Revisit.
92const int kNumSafepointRegisters = 16;
93
94// Define the list of registers actually saved at safepoints.
95// Note that the number of saved registers may be smaller than the reserved
96// space, i.e. kNumSafepointSavedRegisters <= kNumSafepointRegisters.
97const RegList kSafepointSavedRegisters = kJSCallerSaved | kCalleeSaved;
98const int kNumSafepointSavedRegisters = kNumJSCallerSaved + kNumCalleeSaved;
99
100// ----------------------------------------------------
101
102
103class StackHandlerConstants : public AllStatic {
104 public:
105  static const int kNextOffset     = 0 * kPointerSize;
106  static const int kCodeOffset     = 1 * kPointerSize;
107  static const int kStateOffset    = 2 * kPointerSize;
108  static const int kContextOffset  = 3 * kPointerSize;
109  static const int kFPOffset       = 4 * kPointerSize;
110
111  static const int kSize = kFPOffset + kPointerSize;
112};
113
114
115class EntryFrameConstants : public AllStatic {
116 public:
117  static const int kCallerFPOffset      = -3 * kPointerSize;
118};
119
120
121class ExitFrameConstants : public AllStatic {
122 public:
123  static const int kCodeOffset = -2 * kPointerSize;
124  static const int kSPOffset = -1 * kPointerSize;
125
126  // The caller fields are below the frame pointer on the stack.
127  static const int kCallerFPOffset = 0 * kPointerSize;
128  // The calling JS function is below FP.
129  static const int kCallerPCOffset = 1 * kPointerSize;
130
131  // FP-relative displacement of the caller's SP.  It points just
132  // below the saved PC.
133  static const int kCallerSPDisplacement = 2 * kPointerSize;
134};
135
136
137class StandardFrameConstants : public AllStatic {
138 public:
139  // Fixed part of the frame consists of return address, caller fp,
140  // context and function.
141  static const int kFixedFrameSize    =  4 * kPointerSize;
142  static const int kExpressionsOffset = -3 * kPointerSize;
143  static const int kMarkerOffset      = -2 * kPointerSize;
144  static const int kContextOffset     = -1 * kPointerSize;
145  static const int kCallerFPOffset    =  0 * kPointerSize;
146  static const int kCallerPCOffset    =  1 * kPointerSize;
147  static const int kCallerSPOffset    =  2 * kPointerSize;
148};
149
150
151class JavaScriptFrameConstants : public AllStatic {
152 public:
153  // FP-relative.
154  static const int kLocal0Offset = StandardFrameConstants::kExpressionsOffset;
155  static const int kLastParameterOffset = +2 * kPointerSize;
156  static const int kFunctionOffset = StandardFrameConstants::kMarkerOffset;
157
158  // Caller SP-relative.
159  static const int kParam0Offset   = -2 * kPointerSize;
160  static const int kReceiverOffset = -1 * kPointerSize;
161};
162
163
164class ArgumentsAdaptorFrameConstants : public AllStatic {
165 public:
166  static const int kLengthOffset = StandardFrameConstants::kExpressionsOffset;
167  static const int kFrameSize =
168      StandardFrameConstants::kFixedFrameSize + kPointerSize;
169};
170
171
172class InternalFrameConstants : public AllStatic {
173 public:
174  static const int kCodeOffset = StandardFrameConstants::kExpressionsOffset;
175};
176
177
178inline Object* JavaScriptFrame::function_slot_object() const {
179  const int offset = JavaScriptFrameConstants::kFunctionOffset;
180  return Memory::Object_at(fp() + offset);
181}
182
183
184} }  // namespace v8::internal
185
186#endif  // V8_ARM_FRAMES_ARM_H_
187