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      1 // Copyright 2006-2008 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     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 
     31 namespace v8 {
     32 namespace 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:
     38 static const 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
     43 static const int kNumRegs = 16;
     44 
     45 
     46 // Caller-saved/arguments registers
     47 static const RegList kJSCallerSaved =
     48   1 << 0 |  // r0 a1
     49   1 << 1 |  // r1 a2
     50   1 << 2 |  // r2 a3
     51   1 << 3;   // r3 a4
     52 
     53 static const int kNumJSCallerSaved = 4;
     54 
     55 typedef 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
     59 int JSCallerSavedCode(int n);
     60 
     61 
     62 // Callee-saved registers preserved when switching from C to JavaScript
     63 static const 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 static const int kNumCalleeSaved = 7 + kR9Available;
     74 
     75 // Double registers d8 to d15 are callee-saved.
     76 static const int kNumDoubleCalleeSaved = 8;
     77 
     78 
     79 // Number of registers for which space is reserved in safepoints. Must be a
     80 // multiple of 8.
     81 // TODO(regis): Only 8 registers may actually be sufficient. Revisit.
     82 static const int kNumSafepointRegisters = 16;
     83 
     84 // Define the list of registers actually saved at safepoints.
     85 // Note that the number of saved registers may be smaller than the reserved
     86 // space, i.e. kNumSafepointSavedRegisters <= kNumSafepointRegisters.
     87 static const RegList kSafepointSavedRegisters = kJSCallerSaved | kCalleeSaved;
     88 static const int kNumSafepointSavedRegisters =
     89     kNumJSCallerSaved + kNumCalleeSaved;
     90 
     91 // ----------------------------------------------------
     92 
     93 
     94 class StackHandlerConstants : public AllStatic {
     95  public:
     96   static const int kNextOffset  = 0 * kPointerSize;
     97   static const int kStateOffset = 1 * kPointerSize;
     98   static const int kFPOffset    = 2 * kPointerSize;
     99   static const int kPCOffset    = 3 * kPointerSize;
    100 
    101   static const int kSize = kPCOffset + kPointerSize;
    102 };
    103 
    104 
    105 class EntryFrameConstants : public AllStatic {
    106  public:
    107   static const int kCallerFPOffset      = -3 * kPointerSize;
    108 };
    109 
    110 
    111 class ExitFrameConstants : public AllStatic {
    112  public:
    113   static const int kCodeOffset = -2 * kPointerSize;
    114   static const int kSPOffset = -1 * kPointerSize;
    115 
    116   // The caller fields are below the frame pointer on the stack.
    117   static const int kCallerFPOffset = 0 * kPointerSize;
    118   // The calling JS function is below FP.
    119   static const int kCallerPCOffset = 1 * kPointerSize;
    120 
    121   // FP-relative displacement of the caller's SP.  It points just
    122   // below the saved PC.
    123   static const int kCallerSPDisplacement = 2 * kPointerSize;
    124 };
    125 
    126 
    127 class StandardFrameConstants : public AllStatic {
    128  public:
    129   static const int kExpressionsOffset = -3 * kPointerSize;
    130   static const int kMarkerOffset      = -2 * kPointerSize;
    131   static const int kContextOffset     = -1 * kPointerSize;
    132   static const int kCallerFPOffset    =  0 * kPointerSize;
    133   static const int kCallerPCOffset    =  1 * kPointerSize;
    134   static const int kCallerSPOffset    =  2 * kPointerSize;
    135 };
    136 
    137 
    138 class JavaScriptFrameConstants : public AllStatic {
    139  public:
    140   // FP-relative.
    141   static const int kLocal0Offset = StandardFrameConstants::kExpressionsOffset;
    142   static const int kLastParameterOffset = +2 * kPointerSize;
    143   static const int kFunctionOffset = StandardFrameConstants::kMarkerOffset;
    144 
    145   // Caller SP-relative.
    146   static const int kParam0Offset   = -2 * kPointerSize;
    147   static const int kReceiverOffset = -1 * kPointerSize;
    148 };
    149 
    150 
    151 class ArgumentsAdaptorFrameConstants : public AllStatic {
    152  public:
    153   static const int kLengthOffset = StandardFrameConstants::kExpressionsOffset;
    154 };
    155 
    156 
    157 class InternalFrameConstants : public AllStatic {
    158  public:
    159   static const int kCodeOffset = StandardFrameConstants::kExpressionsOffset;
    160 };
    161 
    162 
    163 inline Object* JavaScriptFrame::function_slot_object() const {
    164   const int offset = JavaScriptFrameConstants::kFunctionOffset;
    165   return Memory::Object_at(fp() + offset);
    166 }
    167 
    168 
    169 } }  // namespace v8::internal
    170 
    171 #endif  // V8_ARM_FRAMES_ARM_H_
    172