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_ARM
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 constant pool in the debug break slot code.
32 Assembler::BlockConstPoolScope block_const_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 // mov r2, r2
50 // mov r2, r2
51 // mov r2, r2
52 // mov r2, r2
53 // to a call to the debug break slot code.
54 // ldr ip, [pc, #0]
55 // b skip
56 // <debug break slot code entry point address>
57 // skip:
58 // blx ip
59 Label skip_constant;
60 patcher.masm()->ldr(ip, MemOperand(v8::internal::pc, 0));
61 patcher.masm()->b(&skip_constant);
62 patcher.Emit(code->entry());
63 patcher.masm()->bind(&skip_constant);
64 patcher.masm()->blx(ip);
65 }
66
DebugBreakSlotIsPatched(Address pc)67 bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
68 Instr current_instr = Assembler::instr_at(pc);
69 return !Assembler::IsNop(current_instr, Assembler::DEBUG_BREAK_NOP);
70 }
71
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)72 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
73 DebugBreakCallHelperMode mode) {
74 __ RecordComment("Debug break");
75 {
76 FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
77
78 // Push arguments for DebugBreak call.
79 if (mode == SAVE_RESULT_REGISTER) {
80 // Break on return.
81 __ push(r0);
82 } else {
83 // Non-return breaks.
84 __ Push(masm->isolate()->factory()->the_hole_value());
85 }
86 __ mov(r0, Operand(1));
87 __ mov(r1,
88 Operand(ExternalReference(
89 Runtime::FunctionForId(Runtime::kDebugBreak), masm->isolate())));
90
91 CEntryStub ceb(masm->isolate(), 1);
92 __ CallStub(&ceb);
93
94 if (FLAG_debug_code) {
95 for (int i = 0; i < kNumJSCallerSaved; i++) {
96 Register reg = {JSCallerSavedCode(i)};
97 // Do not clobber r0 if mode is SAVE_RESULT_REGISTER. It will
98 // contain return value of the function.
99 if (!(reg.is(r0) && (mode == SAVE_RESULT_REGISTER))) {
100 __ mov(reg, Operand(kDebugZapValue));
101 }
102 }
103 }
104 // Leave the internal frame.
105 }
106
107 __ MaybeDropFrames();
108
109 // Return to caller.
110 __ Ret();
111 }
112
GenerateHandleDebuggerStatement(MacroAssembler * masm)113 void DebugCodegen::GenerateHandleDebuggerStatement(MacroAssembler* masm) {
114 {
115 FrameScope scope(masm, StackFrame::INTERNAL);
116 __ CallRuntime(Runtime::kHandleDebuggerStatement, 0);
117 }
118 __ MaybeDropFrames();
119
120 // Return to caller.
121 __ Ret();
122 }
123
GenerateFrameDropperTrampoline(MacroAssembler * masm)124 void DebugCodegen::GenerateFrameDropperTrampoline(MacroAssembler* masm) {
125 // Frame is being dropped:
126 // - Drop to the target frame specified by r1.
127 // - Look up current function on the frame.
128 // - Leave the frame.
129 // - Restart the frame by calling the function.
130 __ mov(fp, r1);
131 __ ldr(r1, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
132 __ LeaveFrame(StackFrame::INTERNAL);
133
134 __ ldr(r0, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
135 __ ldr(r0,
136 FieldMemOperand(r0, SharedFunctionInfo::kFormalParameterCountOffset));
137 __ mov(r2, r0);
138
139 ParameterCount dummy1(r2);
140 ParameterCount dummy2(r0);
141 __ InvokeFunction(r1, dummy1, dummy2, JUMP_FUNCTION,
142 CheckDebugStepCallWrapper());
143 }
144
145
146 const bool LiveEdit::kFrameDropperSupported = true;
147
148 #undef __
149
150 } // namespace internal
151 } // namespace v8
152
153 #endif // V8_TARGET_ARCH_ARM
154