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/codegen.h"
8 #include "src/debug/debug.h"
9
10 namespace v8 {
11 namespace internal {
12
13 #define __ ACCESS_MASM(masm)
14
15
EmitDebugBreakSlot(MacroAssembler * masm)16 void EmitDebugBreakSlot(MacroAssembler* masm) {
17 Label check_size;
18 __ bind(&check_size);
19 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
20 __ nop(MacroAssembler::DEBUG_BREAK_NOP);
21 }
22 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
23 masm->InstructionsGeneratedSince(&check_size));
24 }
25
26
GenerateSlot(MacroAssembler * masm,RelocInfo::Mode mode)27 void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode) {
28 // Generate enough nop's to make space for a call instruction. Avoid emitting
29 // the constant pool in the debug break slot code.
30 Assembler::BlockConstPoolScope block_const_pool(masm);
31 masm->RecordDebugBreakSlot(mode);
32 EmitDebugBreakSlot(masm);
33 }
34
35
ClearDebugBreakSlot(Isolate * isolate,Address pc)36 void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) {
37 CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotInstructions);
38 EmitDebugBreakSlot(patcher.masm());
39 }
40
41
PatchDebugBreakSlot(Isolate * isolate,Address pc,Handle<Code> code)42 void DebugCodegen::PatchDebugBreakSlot(Isolate* isolate, Address pc,
43 Handle<Code> code) {
44 DCHECK_EQ(Code::BUILTIN, code->kind());
45 CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotInstructions);
46 // Patch the code changing the debug break slot code from
47 // mov r2, r2
48 // mov r2, r2
49 // mov r2, r2
50 // mov r2, r2
51 // to a call to the debug break slot code.
52 // ldr ip, [pc, #0]
53 // b skip
54 // <debug break slot code entry point address>
55 // skip:
56 // blx ip
57 Label skip_constant;
58 patcher.masm()->ldr(ip, MemOperand(v8::internal::pc, 0));
59 patcher.masm()->b(&skip_constant);
60 patcher.Emit(code->entry());
61 patcher.masm()->bind(&skip_constant);
62 patcher.masm()->blx(ip);
63 }
64
65
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)66 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
67 DebugBreakCallHelperMode mode) {
68 __ RecordComment("Debug break");
69 {
70 FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
71
72 // Load padding words on stack.
73 __ mov(ip, Operand(Smi::FromInt(LiveEdit::kFramePaddingValue)));
74 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
75 __ push(ip);
76 }
77 __ mov(ip, Operand(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
78 __ push(ip);
79
80 if (mode == SAVE_RESULT_REGISTER) __ push(r0);
81
82 __ mov(r0, Operand::Zero()); // no arguments
83 __ mov(r1,
84 Operand(ExternalReference(
85 Runtime::FunctionForId(Runtime::kDebugBreak), masm->isolate())));
86
87 CEntryStub ceb(masm->isolate(), 1);
88 __ CallStub(&ceb);
89
90 if (FLAG_debug_code) {
91 for (int i = 0; i < kNumJSCallerSaved; i++) {
92 Register reg = {JSCallerSavedCode(i)};
93 __ mov(reg, Operand(kDebugZapValue));
94 }
95 }
96
97 if (mode == SAVE_RESULT_REGISTER) __ pop(r0);
98
99 // Don't bother removing padding bytes pushed on the stack
100 // as the frame is going to be restored right away.
101
102 // Leave the internal frame.
103 }
104
105 // Now that the break point has been handled, resume normal execution by
106 // jumping to the target address intended by the caller and that was
107 // overwritten by the address of DebugBreakXXX.
108 ExternalReference after_break_target =
109 ExternalReference::debug_after_break_target_address(masm->isolate());
110 __ mov(ip, Operand(after_break_target));
111 __ ldr(ip, MemOperand(ip));
112 __ Jump(ip);
113 }
114
115
GenerateFrameDropperLiveEdit(MacroAssembler * masm)116 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
117 // Load the function pointer off of our current stack frame.
118 __ ldr(r1, MemOperand(fp,
119 StandardFrameConstants::kConstantPoolOffset - kPointerSize));
120
121 // Pop return address, frame and constant pool pointer (if
122 // FLAG_enable_embedded_constant_pool).
123 __ LeaveFrame(StackFrame::INTERNAL);
124
125 ParameterCount dummy(0);
126 __ FloodFunctionIfStepping(r1, no_reg, dummy, dummy);
127
128 { ConstantPoolUnavailableScope constant_pool_unavailable(masm);
129 // Load context from the function.
130 __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
131
132 // Clear new.target as a safety measure.
133 __ LoadRoot(r3, Heap::kUndefinedValueRootIndex);
134
135 // Get function code.
136 __ ldr(ip, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
137 __ ldr(ip, FieldMemOperand(ip, SharedFunctionInfo::kCodeOffset));
138 __ add(ip, ip, Operand(Code::kHeaderSize - kHeapObjectTag));
139
140 // Re-run JSFunction, r1 is function, cp is context.
141 __ Jump(ip);
142 }
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