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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 #include "src/v8.h" | |
6 | |
7 #if V8_TARGET_ARCH_ARM64 | |
8 | |
9 #include "src/codegen.h" | |
10 #include "src/debug.h" | |
11 | |
12 namespace v8 { | |
13 namespace internal { | |
14 | |
15 #define __ ACCESS_MASM(masm) | |
16 | |
17 | |
18 void EmitDebugBreakSlot(Assembler* masm) { | |
19 Label check_size; | |
20 __ bind(&check_size); | |
21 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) { | |
22 __ nop(Assembler::DEBUG_BREAK_NOP); | |
23 } | |
24 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions, | |
25 static_cast<int>(masm->InstructionsGeneratedSince(&check_size))); | |
26 } | |
27 | |
28 | |
29 void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode, | |
30 int call_argc) { | |
31 // Generate enough nop's to make space for a call instruction. Avoid emitting | |
32 // the constant pool in the debug break slot code. | |
33 InstructionAccurateScope scope(masm, Assembler::kDebugBreakSlotInstructions); | |
34 masm->RecordDebugBreakSlot(mode, call_argc); | |
35 EmitDebugBreakSlot(masm); | |
36 } | |
37 | |
38 | |
39 void DebugCodegen::ClearDebugBreakSlot(Address pc) { | |
40 PatchingAssembler patcher(reinterpret_cast<Instruction*>(pc), | |
41 Assembler::kDebugBreakSlotInstructions); | |
42 EmitDebugBreakSlot(&patcher); | |
43 } | |
44 | |
45 | |
46 void DebugCodegen::PatchDebugBreakSlot(Address pc, Handle<Code> code) { | |
47 DCHECK_EQ(Code::BUILTIN, code->kind()); | |
48 PatchingAssembler patcher(reinterpret_cast<Instruction*>(pc), | |
49 Assembler::kDebugBreakSlotInstructions); | |
50 // Patch the code emitted by DebugCodegen::GenerateSlots, changing the debug | |
51 // break slot code from | |
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 // mov x0, x0 @ nop DEBUG_BREAK_NOP | |
57 // to a call to the debug slot code. | |
58 // ldr ip0, [pc, #(2 * kInstructionSize)] | |
59 // blr ip0 | |
60 // b skip | |
61 // <debug break slot code entry point address (64 bits)> | |
62 // skip: | |
63 | |
64 Label skip_constant; | |
65 // The first instruction of a patched debug break slot must be a load literal | |
66 // loading the address of the debug break slot code. | |
67 patcher.ldr_pcrel(ip0, (2 * kInstructionSize) >> kLoadLiteralScaleLog2); | |
68 patcher.b(&skip_constant); | |
69 patcher.dc64(reinterpret_cast<int64_t>(code->entry())); | |
70 patcher.bind(&skip_constant); | |
71 // TODO(all): check the following is correct. | |
72 // The debug break slot code will push a frame and call statically compiled | |
73 // code. By using blr, this call site will be registered in the frame. | |
74 // The debugger can now iterate on the frames to find this call. | |
75 patcher.blr(ip0); | |
76 } | |
77 | |
78 | |
79 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm, | |
80 DebugBreakCallHelperMode mode) { | |
81 __ RecordComment("Debug break"); | |
82 Register scratch = x10; | |
83 { | |
84 FrameScope scope(masm, StackFrame::INTERNAL); | |
85 | |
86 // Load padding words on stack. | |
87 __ Mov(scratch, Smi::FromInt(LiveEdit::kFramePaddingValue)); | |
88 __ PushMultipleTimes(scratch, LiveEdit::kFramePaddingInitialSize); | |
89 __ Mov(scratch, Smi::FromInt(LiveEdit::kFramePaddingInitialSize)); | |
90 __ Push(scratch); | |
91 | |
92 if (mode == SAVE_RESULT_REGISTER) __ Push(x0); | |
93 | |
94 __ Mov(x0, 0); // No arguments. | |
95 __ Mov(x1, ExternalReference(Runtime::FunctionForId(Runtime::kDebugBreak), | |
96 masm->isolate())); | |
97 | |
98 CEntryStub stub(masm->isolate(), 1); | |
99 __ CallStub(&stub); | |
100 | |
101 if (FLAG_debug_code) { | |
102 for (int i = 0; i < kNumJSCallerSaved; i++) { | |
103 Register reg = Register::XRegFromCode(JSCallerSavedCode(i)); | |
104 __ Mov(reg, Operand(kDebugZapValue)); | |
105 } | |
106 } | |
107 | |
108 // Restore the register values from the expression stack. | |
109 if (mode == SAVE_RESULT_REGISTER) __ Pop(x0); | |
110 | |
111 // Don't bother removing padding bytes pushed on the stack | |
112 // as the frame is going to be restored right away. | |
113 | |
114 // Leave the internal frame. | |
115 } | |
116 | |
117 // Now that the break point has been handled, resume normal execution by | |
118 // jumping to the target address intended by the caller and that was | |
119 // overwritten by the address of DebugBreakXXX. | |
120 ExternalReference after_break_target = | |
121 ExternalReference::debug_after_break_target_address(masm->isolate()); | |
122 __ Mov(scratch, after_break_target); | |
123 __ Ldr(scratch, MemOperand(scratch)); | |
124 __ Br(scratch); | |
125 } | |
126 | |
127 | |
128 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) { | |
129 __ Ret(); | |
130 } | |
131 | |
132 | |
133 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) { | |
134 ExternalReference restarter_frame_function_slot = | |
135 ExternalReference::debug_restarter_frame_function_pointer_address( | |
136 masm->isolate()); | |
137 UseScratchRegisterScope temps(masm); | |
138 Register scratch = temps.AcquireX(); | |
139 | |
140 __ Mov(scratch, restarter_frame_function_slot); | |
141 __ Str(xzr, MemOperand(scratch)); | |
142 | |
143 // We do not know our frame height, but set sp based on fp. | |
144 __ Sub(masm->StackPointer(), fp, kPointerSize); | |
145 __ AssertStackConsistency(); | |
146 | |
147 __ Pop(x1, fp, lr); // Function, Frame, Return address. | |
148 | |
149 // Load context from the function. | |
150 __ Ldr(cp, FieldMemOperand(x1, JSFunction::kContextOffset)); | |
151 | |
152 // Get function code. | |
153 __ Ldr(scratch, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset)); | |
154 __ Ldr(scratch, FieldMemOperand(scratch, SharedFunctionInfo::kCodeOffset)); | |
155 __ Add(scratch, scratch, Code::kHeaderSize - kHeapObjectTag); | |
156 | |
157 // Re-run JSFunction, x1 is function, cp is context. | |
158 __ Br(scratch); | |
159 } | |
160 | |
161 | |
162 const bool LiveEdit::kFrameDropperSupported = true; | |
163 | |
164 } // namespace internal | |
165 } // namespace v8 | |
166 | |
167 #endif // V8_TARGET_ARCH_ARM64 | |
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