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 #if V8_TARGET_ARCH_X64
6
7 #include "src/debug/debug.h"
8
9 #include "src/assembler.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(MacroAssembler * masm)19 void EmitDebugBreakSlot(MacroAssembler* masm) {
20 Label check_codesize;
21 __ bind(&check_codesize);
22 __ Nop(Assembler::kDebugBreakSlotLength);
23 DCHECK_EQ(Assembler::kDebugBreakSlotLength,
24 masm->SizeOfCodeGeneratedSince(&check_codesize));
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.
30 masm->RecordDebugBreakSlot(mode);
31 EmitDebugBreakSlot(masm);
32 }
33
34
ClearDebugBreakSlot(Isolate * isolate,Address pc)35 void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) {
36 CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotLength);
37 EmitDebugBreakSlot(patcher.masm());
38 }
39
40
PatchDebugBreakSlot(Isolate * isolate,Address pc,Handle<Code> code)41 void DebugCodegen::PatchDebugBreakSlot(Isolate* isolate, Address pc,
42 Handle<Code> code) {
43 DCHECK(code->is_debug_stub());
44 static const int kSize = Assembler::kDebugBreakSlotLength;
45 CodePatcher patcher(isolate, pc, kSize);
46 Label check_codesize;
47 patcher.masm()->bind(&check_codesize);
48 patcher.masm()->movp(kScratchRegister, reinterpret_cast<void*>(code->entry()),
49 Assembler::RelocInfoNone());
50 patcher.masm()->call(kScratchRegister);
51 // Check that the size of the code generated is as expected.
52 DCHECK_EQ(kSize, patcher.masm()->SizeOfCodeGeneratedSince(&check_codesize));
53 }
54
DebugBreakSlotIsPatched(Address pc)55 bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
56 return !Assembler::IsNop(pc);
57 }
58
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)59 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
60 DebugBreakCallHelperMode mode) {
61 __ RecordComment("Debug break");
62
63 // Enter an internal frame.
64 {
65 FrameScope scope(masm, StackFrame::INTERNAL);
66
67 // Load padding words on stack.
68 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
69 __ Push(Smi::FromInt(LiveEdit::kFramePaddingValue));
70 }
71 __ Push(Smi::FromInt(LiveEdit::kFramePaddingInitialSize));
72
73 // Push arguments for DebugBreak call.
74 if (mode == SAVE_RESULT_REGISTER) {
75 // Break on return.
76 __ Push(rax);
77 } else {
78 // Non-return breaks.
79 __ Push(masm->isolate()->factory()->the_hole_value());
80 }
81 __ Set(rax, 1);
82 __ Move(rbx, ExternalReference(Runtime::FunctionForId(Runtime::kDebugBreak),
83 masm->isolate()));
84
85 CEntryStub ceb(masm->isolate(), 1);
86 __ CallStub(&ceb);
87
88 if (FLAG_debug_code) {
89 for (int i = 0; i < kNumJSCallerSaved; ++i) {
90 Register reg = {JSCallerSavedCode(i)};
91 // Do not clobber rax if mode is SAVE_RESULT_REGISTER. It will
92 // contain return value of the function.
93 if (!(reg.is(rax) && (mode == SAVE_RESULT_REGISTER))) {
94 __ Set(reg, kDebugZapValue);
95 }
96 }
97 }
98
99 // Read current padding counter and skip corresponding number of words.
100 __ Pop(kScratchRegister);
101 __ SmiToInteger32(kScratchRegister, kScratchRegister);
102 __ leap(rsp, Operand(rsp, kScratchRegister, times_pointer_size, 0));
103
104 // Get rid of the internal frame.
105 }
106
107 // This call did not replace a call , so there will be an unwanted
108 // return address left on the stack. Here we get rid of that.
109 __ addp(rsp, Immediate(kPCOnStackSize));
110
111 // Now that the break point has been handled, resume normal execution by
112 // jumping to the target address intended by the caller and that was
113 // overwritten by the address of DebugBreakXXX.
114 ExternalReference after_break_target =
115 ExternalReference::debug_after_break_target_address(masm->isolate());
116 __ Move(kScratchRegister, after_break_target);
117 __ Jump(Operand(kScratchRegister, 0));
118 }
119
120
GenerateFrameDropperLiveEdit(MacroAssembler * masm)121 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
122 // We do not know our frame height, but set rsp based on rbp.
123 __ leap(rsp, Operand(rbp, FrameDropperFrameConstants::kFunctionOffset));
124 __ Pop(rdi); // Function.
125 __ addp(rsp,
126 Immediate(-FrameDropperFrameConstants::kCodeOffset)); // INTERNAL
127 // frame marker
128 // and code
129 __ popq(rbp);
130
131 ParameterCount dummy(0);
132 __ FloodFunctionIfStepping(rdi, no_reg, dummy, dummy);
133
134 // Load context from the function.
135 __ movp(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
136
137 // Clear new.target as a safety measure.
138 __ LoadRoot(rdx, Heap::kUndefinedValueRootIndex);
139
140 // Get function code.
141 __ movp(rbx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
142 __ movp(rbx, FieldOperand(rbx, SharedFunctionInfo::kCodeOffset));
143 __ leap(rbx, FieldOperand(rbx, Code::kHeaderSize));
144
145 // Re-run JSFunction, rdi is function, rsi is context.
146 __ jmp(rbx);
147 }
148
149 const bool LiveEdit::kFrameDropperSupported = true;
150
151 #undef __
152
153 } // namespace internal
154 } // namespace v8
155
156 #endif // V8_TARGET_ARCH_X64
157