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
EmitDebugBreakSlot(Assembler * masm)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
GenerateSlot(MacroAssembler * masm,RelocInfo::Mode mode)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
ClearDebugBreakSlot(Isolate * isolate,Address pc)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
PatchDebugBreakSlot(Isolate * isolate,Address pc,Handle<Code> code)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
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)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
GenerateFrameDropperLiveEdit(MacroAssembler * masm)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
162