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_MIPS
6
7 #include "src/debug/debug.h"
8
9 #include "src/codegen.h"
10 #include "src/debug/liveedit.h"
11
12 namespace v8 {
13 namespace internal {
14
15 #define __ ACCESS_MASM(masm)
16
17
EmitDebugBreakSlot(MacroAssembler * masm)18 void EmitDebugBreakSlot(MacroAssembler* masm) {
19 Label check_size;
20 __ bind(&check_size);
21 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
22 __ nop(MacroAssembler::DEBUG_BREAK_NOP);
23 }
24 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
25 masm->InstructionsGeneratedSince(&check_size));
26 }
27
28
GenerateSlot(MacroAssembler * masm,RelocInfo::Mode mode)29 void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode) {
30 // Generate enough nop's to make space for a call instruction. Avoid emitting
31 // the trampoline pool in the debug break slot code.
32 Assembler::BlockTrampolinePoolScope block_pool(masm);
33 masm->RecordDebugBreakSlot(mode);
34 EmitDebugBreakSlot(masm);
35 }
36
37
ClearDebugBreakSlot(Isolate * isolate,Address pc)38 void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) {
39 CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotInstructions);
40 EmitDebugBreakSlot(patcher.masm());
41 }
42
43
PatchDebugBreakSlot(Isolate * isolate,Address pc,Handle<Code> code)44 void DebugCodegen::PatchDebugBreakSlot(Isolate* isolate, Address pc,
45 Handle<Code> code) {
46 DCHECK(code->is_debug_stub());
47 CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotInstructions);
48 // Patch the code changing the debug break slot code from:
49 // nop(DEBUG_BREAK_NOP) - nop(1) is sll(zero_reg, zero_reg, 1)
50 // nop(DEBUG_BREAK_NOP)
51 // nop(DEBUG_BREAK_NOP)
52 // nop(DEBUG_BREAK_NOP)
53 // to a call to the debug break slot code.
54 // li t9, address (lui t9 / ori t9 instruction pair)
55 // call t9 (jalr t9 / nop instruction pair)
56 patcher.masm()->li(v8::internal::t9,
57 Operand(reinterpret_cast<int32_t>(code->entry())));
58 patcher.masm()->Call(v8::internal::t9);
59 }
60
DebugBreakSlotIsPatched(Address pc)61 bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
62 Instr current_instr = Assembler::instr_at(pc);
63 return !Assembler::IsNop(current_instr, Assembler::DEBUG_BREAK_NOP);
64 }
65
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)66 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
67 DebugBreakCallHelperMode mode) {
68 __ RecordComment("Debug break");
69 {
70 FrameScope scope(masm, StackFrame::INTERNAL);
71
72 // Push arguments for DebugBreak call.
73 if (mode == SAVE_RESULT_REGISTER) {
74 // Break on return.
75 __ push(v0);
76 } else {
77 // Non-return breaks.
78 __ Push(masm->isolate()->factory()->the_hole_value());
79 }
80 __ PrepareCEntryArgs(1);
81 __ PrepareCEntryFunction(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 v0 if mode is SAVE_RESULT_REGISTER. It will
91 // contain return value of the function returned by DebugBreak.
92 if (!(reg.is(v0) && (mode == SAVE_RESULT_REGISTER))) {
93 __ li(reg, kDebugZapValue);
94 }
95 }
96 }
97 // Leave the internal frame.
98 }
99
100 __ MaybeDropFrames();
101
102 // Return to caller.
103 __ Ret();
104 }
105
GenerateHandleDebuggerStatement(MacroAssembler * masm)106 void DebugCodegen::GenerateHandleDebuggerStatement(MacroAssembler* masm) {
107 {
108 FrameScope scope(masm, StackFrame::INTERNAL);
109 __ CallRuntime(Runtime::kHandleDebuggerStatement, 0);
110 }
111 __ MaybeDropFrames();
112
113 // Return to caller.
114 __ Ret();
115 }
116
GenerateFrameDropperTrampoline(MacroAssembler * masm)117 void DebugCodegen::GenerateFrameDropperTrampoline(MacroAssembler* masm) {
118 // Frame is being dropped:
119 // - Drop to the target frame specified by a1.
120 // - Look up current function on the frame.
121 // - Leave the frame.
122 // - Restart the frame by calling the function.
123 __ mov(fp, a1);
124 __ lw(a1, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
125
126 // Pop return address and frame.
127 __ LeaveFrame(StackFrame::INTERNAL);
128
129 __ lw(a0, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
130 __ lw(a0,
131 FieldMemOperand(a0, SharedFunctionInfo::kFormalParameterCountOffset));
132 __ mov(a2, a0);
133
134 ParameterCount dummy1(a2);
135 ParameterCount dummy2(a0);
136 __ InvokeFunction(a1, dummy1, dummy2, JUMP_FUNCTION,
137 CheckDebugStepCallWrapper());
138 }
139
140
141 const bool LiveEdit::kFrameDropperSupported = true;
142
143 #undef __
144
145 } // namespace internal
146 } // namespace v8
147
148 #endif // V8_TARGET_ARCH_MIPS
149