1 // Copyright 2012 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef V8_ARM_FRAMES_ARM_H_ 6 #define V8_ARM_FRAMES_ARM_H_ 7 8 namespace v8 { 9 namespace internal { 10 11 12 // The ARM ABI does not specify the usage of register r9, which may be reserved 13 // as the static base or thread register on some platforms, in which case we 14 // leave it alone. Adjust the value of kR9Available accordingly: 15 const int kR9Available = 1; // 1 if available to us, 0 if reserved 16 17 18 // Register list in load/store instructions 19 // Note that the bit values must match those used in actual instruction encoding 20 const int kNumRegs = 16; 21 22 23 // Caller-saved/arguments registers 24 const RegList kJSCallerSaved = 25 1 << 0 | // r0 a1 26 1 << 1 | // r1 a2 27 1 << 2 | // r2 a3 28 1 << 3; // r3 a4 29 30 const int kNumJSCallerSaved = 4; 31 32 // Return the code of the n-th caller-saved register available to JavaScript 33 // e.g. JSCallerSavedReg(0) returns r0.code() == 0 34 int JSCallerSavedCode(int n); 35 36 37 // Callee-saved registers preserved when switching from C to JavaScript 38 const RegList kCalleeSaved = 39 1 << 4 | // r4 v1 40 1 << 5 | // r5 v2 41 1 << 6 | // r6 v3 42 1 << 7 | // r7 v4 (cp in JavaScript code) 43 1 << 8 | // r8 v5 (pp in JavaScript code) 44 kR9Available << 9 | // r9 v6 45 1 << 10 | // r10 v7 46 1 << 11; // r11 v8 (fp in JavaScript code) 47 48 // When calling into C++ (only for C++ calls that can't cause a GC). 49 // The call code will take care of lr, fp, etc. 50 const RegList kCallerSaved = 51 1 << 0 | // r0 52 1 << 1 | // r1 53 1 << 2 | // r2 54 1 << 3 | // r3 55 1 << 9; // r9 56 57 58 const int kNumCalleeSaved = 7 + kR9Available; 59 60 // Double registers d8 to d15 are callee-saved. 61 const int kNumDoubleCalleeSaved = 8; 62 63 64 // Number of registers for which space is reserved in safepoints. Must be a 65 // multiple of 8. 66 // TODO(regis): Only 8 registers may actually be sufficient. Revisit. 67 const int kNumSafepointRegisters = 16; 68 69 // The embedded constant pool pointer (r8/pp) is not included in the safepoint 70 // since it is not tagged. This register is preserved in the stack frame where 71 // its value will be updated if GC code movement occurs. Including it in the 72 // safepoint (where it will not be relocated) would cause a stale value to be 73 // restored. 74 const RegList kConstantPointerRegMask = 75 FLAG_enable_embedded_constant_pool ? (1 << 8) : 0; 76 const int kNumConstantPoolPointerReg = 77 FLAG_enable_embedded_constant_pool ? 1 : 0; 78 79 // Define the list of registers actually saved at safepoints. 80 // Note that the number of saved registers may be smaller than the reserved 81 // space, i.e. kNumSafepointSavedRegisters <= kNumSafepointRegisters. 82 const RegList kSafepointSavedRegisters = 83 kJSCallerSaved | (kCalleeSaved & ~kConstantPointerRegMask); 84 const int kNumSafepointSavedRegisters = 85 kNumJSCallerSaved + kNumCalleeSaved - kNumConstantPoolPointerReg; 86 87 // ---------------------------------------------------- 88 89 90 class EntryFrameConstants : public AllStatic { 91 public: 92 static const int kCallerFPOffset = 93 -(StandardFrameConstants::kFixedFrameSizeFromFp + kPointerSize); 94 }; 95 96 class ExitFrameConstants : public TypedFrameConstants { 97 public: 98 static const int kSPOffset = TYPED_FRAME_PUSHED_VALUE_OFFSET(0); 99 static const int kCodeOffset = TYPED_FRAME_PUSHED_VALUE_OFFSET(1); 100 DEFINE_TYPED_FRAME_SIZES(2); 101 102 // The caller fields are below the frame pointer on the stack. 103 static const int kCallerFPOffset = 0 * kPointerSize; 104 // The calling JS function is below FP. 105 static const int kCallerPCOffset = 1 * kPointerSize; 106 107 // FP-relative displacement of the caller's SP. It points just 108 // below the saved PC. 109 static const int kCallerSPDisplacement = 2 * kPointerSize; 110 }; 111 112 113 class JavaScriptFrameConstants : public AllStatic { 114 public: 115 // FP-relative. 116 static const int kLocal0Offset = StandardFrameConstants::kExpressionsOffset; 117 static const int kLastParameterOffset = +2 * kPointerSize; 118 static const int kFunctionOffset = StandardFrameConstants::kFunctionOffset; 119 120 // Caller SP-relative. 121 static const int kParam0Offset = -2 * kPointerSize; 122 static const int kReceiverOffset = -1 * kPointerSize; 123 }; 124 125 126 } // namespace internal 127 } // namespace v8 128 129 #endif // V8_ARM_FRAMES_ARM_H_ 130
