Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2013 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 | #if V8_TARGET_ARCH_ARM64 |
| 6 | |
| 7 | #include "src/arm64/frames-arm64.h" |
| 8 | #include "src/codegen.h" |
| 9 | #include "src/debug/debug.h" |
| 10 | |
| 11 | namespace v8 { |
| 12 | namespace internal { |
| 13 | |
| 14 | #define __ ACCESS_MASM(masm) |
| 15 | |
| 16 | |
| 17 | void EmitDebugBreakSlot(Assembler* masm) { |
| 18 | Label check_size; |
| 19 | __ bind(&check_size); |
| 20 | for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) { |
| 21 | __ nop(Assembler::DEBUG_BREAK_NOP); |
| 22 | } |
| 23 | DCHECK_EQ(Assembler::kDebugBreakSlotInstructions, |
| 24 | static_cast<int>(masm->InstructionsGeneratedSince(&check_size))); |
| 25 | } |
| 26 | |
| 27 | |
| 28 | void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode) { |
| 29 | // Generate enough nop's to make space for a call instruction. Avoid emitting |
| 30 | // the constant pool in the debug break slot code. |
| 31 | InstructionAccurateScope scope(masm, Assembler::kDebugBreakSlotInstructions); |
| 32 | masm->RecordDebugBreakSlot(mode); |
| 33 | EmitDebugBreakSlot(masm); |
| 34 | } |
| 35 | |
| 36 | |
| 37 | void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) { |
| 38 | PatchingAssembler patcher(isolate, reinterpret_cast<Instruction*>(pc), |
| 39 | Assembler::kDebugBreakSlotInstructions); |
| 40 | EmitDebugBreakSlot(&patcher); |
| 41 | } |
| 42 | |
| 43 | |
| 44 | void DebugCodegen::PatchDebugBreakSlot(Isolate* isolate, Address pc, |
| 45 | Handle<Code> code) { |
| 46 | DCHECK_EQ(Code::BUILTIN, code->kind()); |
| 47 | PatchingAssembler patcher(isolate, reinterpret_cast<Instruction*>(pc), |
| 48 | Assembler::kDebugBreakSlotInstructions); |
| 49 | // Patch the code emitted by DebugCodegen::GenerateSlots, changing the debug |
| 50 | // break slot code from |
| 51 | // mov x0, x0 @ nop DEBUG_BREAK_NOP |
| 52 | // mov x0, x0 @ nop DEBUG_BREAK_NOP |
| 53 | // mov x0, x0 @ nop DEBUG_BREAK_NOP |
| 54 | // mov x0, x0 @ nop DEBUG_BREAK_NOP |
| 55 | // mov x0, x0 @ nop DEBUG_BREAK_NOP |
| 56 | // to a call to the debug slot code. |
| 57 | // ldr ip0, [pc, #(2 * kInstructionSize)] |
| 58 | // blr ip0 |
| 59 | // b skip |
| 60 | // <debug break slot code entry point address (64 bits)> |
| 61 | // skip: |
| 62 | |
| 63 | Label skip_constant; |
| 64 | // The first instruction of a patched debug break slot must be a load literal |
| 65 | // loading the address of the debug break slot code. |
| 66 | patcher.ldr_pcrel(ip0, (2 * kInstructionSize) >> kLoadLiteralScaleLog2); |
| 67 | patcher.b(&skip_constant); |
| 68 | patcher.dc64(reinterpret_cast<int64_t>(code->entry())); |
| 69 | patcher.bind(&skip_constant); |
| 70 | // TODO(all): check the following is correct. |
| 71 | // The debug break slot code will push a frame and call statically compiled |
| 72 | // code. By using blr, this call site will be registered in the frame. |
| 73 | // The debugger can now iterate on the frames to find this call. |
| 74 | patcher.blr(ip0); |
| 75 | } |
| 76 | |
| 77 | |
| 78 | void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm, |
| 79 | DebugBreakCallHelperMode mode) { |
| 80 | __ RecordComment("Debug break"); |
| 81 | Register scratch = x10; |
| 82 | { |
| 83 | FrameScope scope(masm, StackFrame::INTERNAL); |
| 84 | |
| 85 | // Load padding words on stack. |
| 86 | __ Mov(scratch, Smi::FromInt(LiveEdit::kFramePaddingValue)); |
| 87 | __ PushMultipleTimes(scratch, LiveEdit::kFramePaddingInitialSize); |
| 88 | __ Mov(scratch, Smi::FromInt(LiveEdit::kFramePaddingInitialSize)); |
| 89 | __ Push(scratch); |
| 90 | |
| 91 | if (mode == SAVE_RESULT_REGISTER) __ Push(x0); |
| 92 | |
| 93 | __ Mov(x0, 0); // No arguments. |
| 94 | __ Mov(x1, ExternalReference(Runtime::FunctionForId(Runtime::kDebugBreak), |
| 95 | masm->isolate())); |
| 96 | |
| 97 | CEntryStub stub(masm->isolate(), 1); |
| 98 | __ CallStub(&stub); |
| 99 | |
| 100 | if (FLAG_debug_code) { |
| 101 | for (int i = 0; i < kNumJSCallerSaved; i++) { |
| 102 | Register reg = Register::XRegFromCode(JSCallerSavedCode(i)); |
| 103 | __ Mov(reg, Operand(kDebugZapValue)); |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | // Restore the register values from the expression stack. |
| 108 | if (mode == SAVE_RESULT_REGISTER) __ Pop(x0); |
| 109 | |
| 110 | // Don't bother removing padding bytes pushed on the stack |
| 111 | // as the frame is going to be restored right away. |
| 112 | |
| 113 | // Leave the internal frame. |
| 114 | } |
| 115 | |
| 116 | // Now that the break point has been handled, resume normal execution by |
| 117 | // jumping to the target address intended by the caller and that was |
| 118 | // overwritten by the address of DebugBreakXXX. |
| 119 | ExternalReference after_break_target = |
| 120 | ExternalReference::debug_after_break_target_address(masm->isolate()); |
| 121 | __ Mov(scratch, after_break_target); |
| 122 | __ Ldr(scratch, MemOperand(scratch)); |
| 123 | __ Br(scratch); |
| 124 | } |
| 125 | |
| 126 | |
| 127 | void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) { |
| 128 | // We do not know our frame height, but set sp based on fp. |
| 129 | __ Sub(masm->StackPointer(), fp, kPointerSize); |
| 130 | __ AssertStackConsistency(); |
| 131 | |
| 132 | __ Pop(x1, fp, lr); // Function, Frame, Return address. |
| 133 | |
| 134 | ParameterCount dummy(0); |
| 135 | __ FloodFunctionIfStepping(x1, no_reg, dummy, dummy); |
| 136 | |
| 137 | UseScratchRegisterScope temps(masm); |
| 138 | Register scratch = temps.AcquireX(); |
| 139 | |
| 140 | // Load context from the function. |
| 141 | __ Ldr(cp, FieldMemOperand(x1, JSFunction::kContextOffset)); |
| 142 | |
| 143 | // Clear new.target as a safety measure. |
| 144 | __ LoadRoot(x3, Heap::kUndefinedValueRootIndex); |
| 145 | |
| 146 | // Get function code. |
| 147 | __ Ldr(scratch, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset)); |
| 148 | __ Ldr(scratch, FieldMemOperand(scratch, SharedFunctionInfo::kCodeOffset)); |
| 149 | __ Add(scratch, scratch, Code::kHeaderSize - kHeapObjectTag); |
| 150 | |
| 151 | // Re-run JSFunction, x1 is function, cp is context. |
| 152 | __ Br(scratch); |
| 153 | } |
| 154 | |
| 155 | |
| 156 | const bool LiveEdit::kFrameDropperSupported = true; |
| 157 | |
| 158 | } // namespace internal |
| 159 | } // namespace v8 |
| 160 | |
| 161 | #endif // V8_TARGET_ARCH_ARM64 |