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
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(code->is_debug_stub());
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
DebugBreakSlotIsPatched(Address pc)53 bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
54 return !Assembler::IsNop(pc);
55 }
56
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)57 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
58 DebugBreakCallHelperMode mode) {
59 __ RecordComment("Debug break");
60
61 // Enter an internal frame.
62 {
63 FrameScope scope(masm, StackFrame::INTERNAL);
64
65 // Load padding words on stack.
66 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
67 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingValue)));
68 }
69 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
70
71 // Push arguments for DebugBreak call.
72 if (mode == SAVE_RESULT_REGISTER) {
73 // Break on return.
74 __ push(eax);
75 } else {
76 // Non-return breaks.
77 __ Push(masm->isolate()->factory()->the_hole_value());
78 }
79 __ Move(eax, Immediate(1));
80 __ mov(ebx,
81 Immediate(ExternalReference(
82 Runtime::FunctionForId(Runtime::kDebugBreak), masm->isolate())));
83
84 CEntryStub ceb(masm->isolate(), 1);
85 __ CallStub(&ceb);
86
87 if (FLAG_debug_code) {
88 for (int i = 0; i < kNumJSCallerSaved; ++i) {
89 Register reg = {JSCallerSavedCode(i)};
90 // Do not clobber eax if mode is SAVE_RESULT_REGISTER. It will
91 // contain return value of the function.
92 if (!(reg.is(eax) && (mode == SAVE_RESULT_REGISTER))) {
93 __ Move(reg, Immediate(kDebugZapValue));
94 }
95 }
96 }
97
98 __ pop(ebx);
99 // We divide stored value by 2 (untagging) and multiply it by word's size.
100 STATIC_ASSERT(kSmiTagSize == 1 && kSmiShiftSize == 0);
101 __ lea(esp, Operand(esp, ebx, times_half_pointer_size, 0));
102
103 // Get rid of the internal frame.
104 }
105
106 // This call did not replace a call , so there will be an unwanted
107 // return address left on the stack. Here we get rid of that.
108 __ add(esp, Immediate(kPointerSize));
109
110 // Now that the break point has been handled, resume normal execution by
111 // jumping to the target address intended by the caller and that was
112 // overwritten by the address of DebugBreakXXX.
113 ExternalReference after_break_target =
114 ExternalReference::debug_after_break_target_address(masm->isolate());
115 __ jmp(Operand::StaticVariable(after_break_target));
116 }
117
118
GenerateFrameDropperLiveEdit(MacroAssembler * masm)119 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
120 // We do not know our frame height, but set esp based on ebp.
121 __ lea(esp, Operand(ebp, FrameDropperFrameConstants::kFunctionOffset));
122 __ pop(edi); // Function.
123 __ add(esp, Immediate(-FrameDropperFrameConstants::kCodeOffset)); // INTERNAL
124 // frame
125 // marker
126 // and code
127 __ pop(ebp);
128
129 ParameterCount dummy(0);
130 __ FloodFunctionIfStepping(edi, no_reg, dummy, dummy);
131
132 // Load context from the function.
133 __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
134
135 // Clear new.target register as a safety measure.
136 __ mov(edx, masm->isolate()->factory()->undefined_value());
137
138 // Get function code.
139 __ mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
140 __ mov(ebx, FieldOperand(ebx, SharedFunctionInfo::kCodeOffset));
141 __ lea(ebx, FieldOperand(ebx, Code::kHeaderSize));
142
143 // Re-run JSFunction, edi is function, esi is context.
144 __ jmp(ebx);
145 }
146
147
148 const bool LiveEdit::kFrameDropperSupported = true;
149
150 #undef __
151
152 } // namespace internal
153 } // namespace v8
154
155 #endif // V8_TARGET_ARCH_X87
156