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_IA32
6
7 #include "src/codegen.h"
8 #include "src/debug/debug.h"
9 #include "src/ia32/frames-ia32.h"
10
11 namespace v8 {
12 namespace internal {
13
14 #define __ ACCESS_MASM(masm)
15
16
EmitDebugBreakSlot(MacroAssembler * masm)17 void EmitDebugBreakSlot(MacroAssembler* masm) {
18 Label check_codesize;
19 __ bind(&check_codesize);
20 __ Nop(Assembler::kDebugBreakSlotLength);
21 DCHECK_EQ(Assembler::kDebugBreakSlotLength,
22 masm->SizeOfCodeGeneratedSince(&check_codesize));
23 }
24
25
GenerateSlot(MacroAssembler * masm,RelocInfo::Mode mode)26 void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode) {
27 // Generate enough nop's to make space for a call instruction.
28 masm->RecordDebugBreakSlot(mode);
29 EmitDebugBreakSlot(masm);
30 }
31
32
ClearDebugBreakSlot(Isolate * isolate,Address pc)33 void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) {
34 CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotLength);
35 EmitDebugBreakSlot(patcher.masm());
36 }
37
38
PatchDebugBreakSlot(Isolate * isolate,Address pc,Handle<Code> code)39 void DebugCodegen::PatchDebugBreakSlot(Isolate* isolate, Address pc,
40 Handle<Code> code) {
41 DCHECK_EQ(Code::BUILTIN, code->kind());
42 static const int kSize = Assembler::kDebugBreakSlotLength;
43 CodePatcher patcher(isolate, pc, kSize);
44
45 // Add a label for checking the size of the code used for returning.
46 Label check_codesize;
47 patcher.masm()->bind(&check_codesize);
48 patcher.masm()->call(code->entry(), RelocInfo::NONE32);
49 // Check that the size of the code generated is as expected.
50 DCHECK_EQ(kSize, patcher.masm()->SizeOfCodeGeneratedSince(&check_codesize));
51 }
52
53
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)54 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
55 DebugBreakCallHelperMode mode) {
56 __ RecordComment("Debug break");
57
58 // Enter an internal frame.
59 {
60 FrameScope scope(masm, StackFrame::INTERNAL);
61
62 // Load padding words on stack.
63 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
64 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingValue)));
65 }
66 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
67
68 if (mode == SAVE_RESULT_REGISTER) __ push(eax);
69
70 __ Move(eax, Immediate(0)); // No arguments.
71 __ mov(ebx,
72 Immediate(ExternalReference(
73 Runtime::FunctionForId(Runtime::kDebugBreak), masm->isolate())));
74
75 CEntryStub ceb(masm->isolate(), 1);
76 __ CallStub(&ceb);
77
78 if (FLAG_debug_code) {
79 for (int i = 0; i < kNumJSCallerSaved; ++i) {
80 Register reg = {JSCallerSavedCode(i)};
81 __ Move(reg, Immediate(kDebugZapValue));
82 }
83 }
84
85 if (mode == SAVE_RESULT_REGISTER) __ pop(eax);
86
87 __ pop(ebx);
88 // We divide stored value by 2 (untagging) and multiply it by word's size.
89 STATIC_ASSERT(kSmiTagSize == 1 && kSmiShiftSize == 0);
90 __ lea(esp, Operand(esp, ebx, times_half_pointer_size, 0));
91
92 // Get rid of the internal frame.
93 }
94
95 // This call did not replace a call , so there will be an unwanted
96 // return address left on the stack. Here we get rid of that.
97 __ add(esp, Immediate(kPointerSize));
98
99 // Now that the break point has been handled, resume normal execution by
100 // jumping to the target address intended by the caller and that was
101 // overwritten by the address of DebugBreakXXX.
102 ExternalReference after_break_target =
103 ExternalReference::debug_after_break_target_address(masm->isolate());
104 __ jmp(Operand::StaticVariable(after_break_target));
105 }
106
107
GenerateFrameDropperLiveEdit(MacroAssembler * masm)108 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
109 // We do not know our frame height, but set esp based on ebp.
110 __ lea(esp, Operand(ebp, -1 * kPointerSize));
111
112 __ pop(edi); // Function.
113 __ pop(ebp);
114
115 ParameterCount dummy(0);
116 __ FloodFunctionIfStepping(edi, no_reg, dummy, dummy);
117
118 // Load context from the function.
119 __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
120
121 // Clear new.target register as a safety measure.
122 __ mov(edx, masm->isolate()->factory()->undefined_value());
123
124 // Get function code.
125 __ mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
126 __ mov(ebx, FieldOperand(ebx, SharedFunctionInfo::kCodeOffset));
127 __ lea(ebx, FieldOperand(ebx, Code::kHeaderSize));
128
129 // Re-run JSFunction, edi is function, esi is context.
130 __ jmp(ebx);
131 }
132
133
134 const bool LiveEdit::kFrameDropperSupported = true;
135
136 #undef __
137
138 } // namespace internal
139 } // namespace v8
140
141 #endif // V8_TARGET_ARCH_IA32
142