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/codegen.h"
8#include "src/debug/debug.h"
9#include "src/x87/frames-x87.h"
10
11namespace v8 {
12namespace internal {
13
14#define __ ACCESS_MASM(masm)
15
16
17void 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
26void 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
33void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) {
34  CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotLength);
35  EmitDebugBreakSlot(patcher.masm());
36}
37
38
39void 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
54void 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
108void 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
134const bool LiveEdit::kFrameDropperSupported = true;
135
136#undef __
137
138}  // namespace internal
139}  // namespace v8
140
141#endif  // V8_TARGET_ARCH_X87
142