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/debug/debug.h"
8
9 #include "src/arm64/frames-arm64.h"
10 #include "src/codegen.h"
11 #include "src/debug/liveedit.h"
12
13 namespace v8 {
14 namespace internal {
15
16 #define __ ACCESS_MASM(masm)
17
18
EmitDebugBreakSlot(Assembler * masm)19 void EmitDebugBreakSlot(Assembler* masm) {
20 Label check_size;
21 __ bind(&check_size);
22 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
23 __ nop(Assembler::DEBUG_BREAK_NOP);
24 }
25 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
26 static_cast<int>(masm->InstructionsGeneratedSince(&check_size)));
27 }
28
29
GenerateSlot(MacroAssembler * masm,RelocInfo::Mode mode)30 void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode) {
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);
35 EmitDebugBreakSlot(masm);
36 }
37
38
ClearDebugBreakSlot(Isolate * isolate,Address pc)39 void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) {
40 PatchingAssembler patcher(isolate, reinterpret_cast<Instruction*>(pc),
41 Assembler::kDebugBreakSlotInstructions);
42 EmitDebugBreakSlot(&patcher);
43 }
44
45
PatchDebugBreakSlot(Isolate * isolate,Address pc,Handle<Code> code)46 void DebugCodegen::PatchDebugBreakSlot(Isolate* isolate, Address pc,
47 Handle<Code> code) {
48 DCHECK(code->is_debug_stub());
49 PatchingAssembler patcher(isolate, reinterpret_cast<Instruction*>(pc),
50 Assembler::kDebugBreakSlotInstructions);
51 // Patch the code emitted by DebugCodegen::GenerateSlots, changing the debug
52 // break slot code from
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 // mov x0, x0 @ nop DEBUG_BREAK_NOP
58 // to a call to the debug slot code.
59 // ldr ip0, [pc, #(2 * kInstructionSize)]
60 // blr ip0
61 // b skip
62 // <debug break slot code entry point address (64 bits)>
63 // skip:
64
65 Label skip_constant;
66 // The first instruction of a patched debug break slot must be a load literal
67 // loading the address of the debug break slot code.
68 patcher.ldr_pcrel(ip0, (2 * kInstructionSize) >> kLoadLiteralScaleLog2);
69 patcher.b(&skip_constant);
70 patcher.dc64(reinterpret_cast<int64_t>(code->entry()));
71 patcher.bind(&skip_constant);
72 // TODO(all): check the following is correct.
73 // The debug break slot code will push a frame and call statically compiled
74 // code. By using blr, this call site will be registered in the frame.
75 // The debugger can now iterate on the frames to find this call.
76 patcher.blr(ip0);
77 }
78
DebugBreakSlotIsPatched(Address pc)79 bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
80 Instruction* current_instr = reinterpret_cast<Instruction*>(pc);
81 return !current_instr->IsNop(Assembler::DEBUG_BREAK_NOP);
82 }
83
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)84 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
85 DebugBreakCallHelperMode mode) {
86 __ RecordComment("Debug break");
87 Register scratch = x10;
88 {
89 FrameScope scope(masm, StackFrame::INTERNAL);
90
91 // Push arguments for DebugBreak call.
92 if (mode == SAVE_RESULT_REGISTER) {
93 // Break on return.
94 __ Push(x0);
95 } else {
96 // Non-return breaks.
97 __ Push(masm->isolate()->factory()->the_hole_value());
98 }
99 __ Mov(x0, 1);
100 __ Mov(x1, ExternalReference(Runtime::FunctionForId(Runtime::kDebugBreak),
101 masm->isolate()));
102
103 CEntryStub stub(masm->isolate(), 1);
104 __ CallStub(&stub);
105
106 if (FLAG_debug_code) {
107 for (int i = 0; i < kNumJSCallerSaved; i++) {
108 Register reg = Register::XRegFromCode(JSCallerSavedCode(i));
109 // Do not clobber x0 if mode is SAVE_RESULT_REGISTER. It will
110 // contain return value of the function.
111 if (!(reg.is(x0) && (mode == SAVE_RESULT_REGISTER))) {
112 __ Mov(reg, Operand(kDebugZapValue));
113 }
114 }
115 }
116 // Leave the internal frame.
117 }
118
119 __ MaybeDropFrames();
120
121 // Return to caller.
122 __ Ret();
123 }
124
GenerateHandleDebuggerStatement(MacroAssembler * masm)125 void DebugCodegen::GenerateHandleDebuggerStatement(MacroAssembler* masm) {
126 {
127 FrameScope scope(masm, StackFrame::INTERNAL);
128 __ CallRuntime(Runtime::kHandleDebuggerStatement, 0);
129 }
130 __ MaybeDropFrames();
131
132 // Return to caller.
133 __ Ret();
134 }
135
GenerateFrameDropperTrampoline(MacroAssembler * masm)136 void DebugCodegen::GenerateFrameDropperTrampoline(MacroAssembler* masm) {
137 // Frame is being dropped:
138 // - Drop to the target frame specified by x1.
139 // - Look up current function on the frame.
140 // - Leave the frame.
141 // - Restart the frame by calling the function.
142 __ Mov(fp, x1);
143 __ AssertStackConsistency();
144 __ Ldr(x1, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
145
146 __ Mov(masm->StackPointer(), Operand(fp));
147 __ Pop(fp, lr); // Frame, Return address.
148
149 __ Ldr(x0, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
150 __ Ldr(x0,
151 FieldMemOperand(x0, SharedFunctionInfo::kFormalParameterCountOffset));
152 __ mov(x2, x0);
153
154 ParameterCount dummy1(x2);
155 ParameterCount dummy2(x0);
156 __ InvokeFunction(x1, dummy1, dummy2, JUMP_FUNCTION,
157 CheckDebugStepCallWrapper());
158 }
159
160
161 const bool LiveEdit::kFrameDropperSupported = true;
162
163 } // namespace internal
164 } // namespace v8
165
166 #endif // V8_TARGET_ARCH_ARM64
167