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_X87
6
7 #include "src/debug/debug.h"
8
9 #include "src/codegen.h"
10 #include "src/debug/liveedit.h"
11 #include "src/x87/frames-x87.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
47 // Add a label for checking the size of the code used for returning.
48 Label check_codesize;
49 patcher.masm()->bind(&check_codesize);
50 patcher.masm()->call(code->entry(), RelocInfo::NONE32);
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(Immediate(Smi::FromInt(LiveEdit::kFramePaddingValue)));
70 }
71 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
72
73 // Push arguments for DebugBreak call.
74 if (mode == SAVE_RESULT_REGISTER) {
75 // Break on return.
76 __ push(eax);
77 } else {
78 // Non-return breaks.
79 __ Push(masm->isolate()->factory()->the_hole_value());
80 }
81 __ Move(eax, Immediate(1));
82 __ mov(ebx,
83 Immediate(ExternalReference(
84 Runtime::FunctionForId(Runtime::kDebugBreak), masm->isolate())));
85
86 CEntryStub ceb(masm->isolate(), 1);
87 __ CallStub(&ceb);
88
89 if (FLAG_debug_code) {
90 for (int i = 0; i < kNumJSCallerSaved; ++i) {
91 Register reg = {JSCallerSavedCode(i)};
92 // Do not clobber eax if mode is SAVE_RESULT_REGISTER. It will
93 // contain return value of the function.
94 if (!(reg.is(eax) && (mode == SAVE_RESULT_REGISTER))) {
95 __ Move(reg, Immediate(kDebugZapValue));
96 }
97 }
98 }
99
100 __ pop(ebx);
101 // We divide stored value by 2 (untagging) and multiply it by word's size.
102 STATIC_ASSERT(kSmiTagSize == 1 && kSmiShiftSize == 0);
103 __ lea(esp, Operand(esp, ebx, times_half_pointer_size, 0));
104
105 // Get rid of the internal frame.
106 }
107
108 // This call did not replace a call , so there will be an unwanted
109 // return address left on the stack. Here we get rid of that.
110 __ add(esp, Immediate(kPointerSize));
111
112 // Now that the break point has been handled, resume normal execution by
113 // jumping to the target address intended by the caller and that was
114 // overwritten by the address of DebugBreakXXX.
115 ExternalReference after_break_target =
116 ExternalReference::debug_after_break_target_address(masm->isolate());
117 __ jmp(Operand::StaticVariable(after_break_target));
118 }
119
120
GenerateFrameDropperLiveEdit(MacroAssembler * masm)121 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
122 // We do not know our frame height, but set esp based on ebp.
123 __ lea(esp, Operand(ebp, FrameDropperFrameConstants::kFunctionOffset));
124 __ pop(edi); // Function.
125 __ add(esp, Immediate(-FrameDropperFrameConstants::kCodeOffset)); // INTERNAL
126 // frame
127 // marker
128 // and code
129 __ pop(ebp);
130
131 ParameterCount dummy(0);
132 __ CheckDebugHook(edi, no_reg, dummy, dummy);
133
134 // Load context from the function.
135 __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
136
137 // Clear new.target register as a safety measure.
138 __ mov(edx, masm->isolate()->factory()->undefined_value());
139
140 // Get function code.
141 __ mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
142 __ mov(ebx, FieldOperand(ebx, SharedFunctionInfo::kCodeOffset));
143 __ lea(ebx, FieldOperand(ebx, Code::kHeaderSize));
144
145 // Re-run JSFunction, edi is function, esi is context.
146 __ jmp(ebx);
147 }
148
149
150 const bool LiveEdit::kFrameDropperSupported = true;
151
152 #undef __
153
154 } // namespace internal
155 } // namespace v8
156
157 #endif // V8_TARGET_ARCH_X87
158