CSE2410 Fall 2014 Bounce

// Copyright 2012 the V8 project authors. All rights reserved.

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// modification, are permitted provided that the following conditions are

// met:

//

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//       from this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_ARM_FRAMES_ARM_H_

#define V8_ARM_FRAMES_ARM_H_

namespace v8 {

namespace internal {

// The ARM ABI does not specify the usage of register r9, which may be reserved

// as the static base or thread register on some platforms, in which case we

// leave it alone. Adjust the value of kR9Available accordingly:

const int kR9Available = 1;  // 1 if available to us, 0 if reserved

// Register list in load/store instructions

// Note that the bit values must match those used in actual instruction encoding

const int kNumRegs = 16;

// Caller-saved/arguments registers

const RegList kJSCallerSaved =

  1 << 0 |  // r0 a1

  1 << 1 |  // r1 a2

  1 << 2 |  // r2 a3

  1 << 3;   // r3 a4

const int kNumJSCallerSaved = 4;

typedef Object* JSCallerSavedBuffer[kNumJSCallerSaved];

// Return the code of the n-th caller-saved register available to JavaScript

// e.g. JSCallerSavedReg(0) returns r0.code() == 0

int JSCallerSavedCode(int n);

// Callee-saved registers preserved when switching from C to JavaScript

const RegList kCalleeSaved =

  1 <<  4 |  //  r4 v1

  1 <<  5 |  //  r5 v2

  1 <<  6 |  //  r6 v3

  1 <<  7 |  //  r7 v4 (pp in JavaScript code)

  1 <<  8 |  //  r8 v5 (cp in JavaScript code)

  kR9Available <<  9 |  //  r9 v6

  1 << 10 |  // r10 v7

  1 << 11;   // r11 v8 (fp in JavaScript code)

// When calling into C++ (only for C++ calls that can't cause a GC).

// The call code will take care of lr, fp, etc.

const RegList kCallerSaved =

  1 <<  0 |  // r0

  1 <<  1 |  // r1

  1 <<  2 |  // r2

  1 <<  3 |  // r3

  1 <<  9;   // r9

const int kNumCalleeSaved = 7 + kR9Available;

// Double registers d8 to d15 are callee-saved.

const int kNumDoubleCalleeSaved = 8;

// Number of registers for which space is reserved in safepoints. Must be a

// multiple of 8.

// TODO(regis): Only 8 registers may actually be sufficient. Revisit.

const int kNumSafepointRegisters = 16;

// Define the list of registers actually saved at safepoints.

// Note that the number of saved registers may be smaller than the reserved

// space, i.e. kNumSafepointSavedRegisters <= kNumSafepointRegisters.

const RegList kSafepointSavedRegisters = kJSCallerSaved | kCalleeSaved;

const int kNumSafepointSavedRegisters = kNumJSCallerSaved + kNumCalleeSaved;

// ----------------------------------------------------

class EntryFrameConstants : public AllStatic {

 public:

  static const int kCallerFPOffset      = -3 * kPointerSize;

};

class ExitFrameConstants : public AllStatic {

 public:

  static const int kCodeOffset = -2 * kPointerSize;

  static const int kSPOffset = -1 * kPointerSize;

  // The caller fields are below the frame pointer on the stack.

  static const int kCallerFPOffset = 0 * kPointerSize;

  // The calling JS function is below FP.

  static const int kCallerPCOffset = 1 * kPointerSize;

  // FP-relative displacement of the caller's SP.  It points just

  // below the saved PC.

  static const int kCallerSPDisplacement = 2 * kPointerSize;

};

class JavaScriptFrameConstants : public AllStatic {

 public:

  // FP-relative.

  static const int kLocal0Offset = StandardFrameConstants::kExpressionsOffset;

  static const int kLastParameterOffset = +2 * kPointerSize;

  static const int kFunctionOffset = StandardFrameConstants::kMarkerOffset;

  // Caller SP-relative.

  static const int kParam0Offset   = -2 * kPointerSize;

  static const int kReceiverOffset = -1 * kPointerSize;

};

class ArgumentsAdaptorFrameConstants : public AllStatic {

 public:

  // FP-relative.

  static const int kLengthOffset = StandardFrameConstants::kExpressionsOffset;

  static const int kFrameSize =

      StandardFrameConstants::kFixedFrameSize + kPointerSize;

};

class ConstructFrameConstants : public AllStatic {

 public:

  // FP-relative.

  static const int kImplicitReceiverOffset = -6 * kPointerSize;

  static const int kConstructorOffset      = -5 * kPointerSize;

  static const int kLengthOffset           = -4 * kPointerSize;

  static const int kCodeOffset = StandardFrameConstants::kExpressionsOffset;

  static const int kFrameSize =

      StandardFrameConstants::kFixedFrameSize + 4 * kPointerSize;

};

class InternalFrameConstants : public AllStatic {

 public:

  // FP-relative.

  static const int kCodeOffset = StandardFrameConstants::kExpressionsOffset;

};

inline Object* JavaScriptFrame::function_slot_object() const {

  const int offset = JavaScriptFrameConstants::kFunctionOffset;

  return Memory::Object_at(fp() + offset);

}

inline void StackHandler::SetFp(Address slot, Address fp) {

  Memory::Address_at(slot) = fp;

}

} }  // namespace v8::internal

#endif  // V8_ARM_FRAMES_ARM_H_