1 // Copyright 2014 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_PPC
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_trampoline_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 //
50 // ori r3, r3, 0
51 // ori r3, r3, 0
52 // ori r3, r3, 0
53 // ori r3, r3, 0
54 // ori r3, r3, 0
55 //
56 // to a call to the debug break code, using a FIXED_SEQUENCE.
57 //
58 // mov r0, <address>
59 // mtlr r0
60 // blrl
61 //
62 Assembler::BlockTrampolinePoolScope block_trampoline_pool(patcher.masm());
63 patcher.masm()->mov(v8::internal::r0,
64 Operand(reinterpret_cast<intptr_t>(code->entry())));
65 patcher.masm()->mtctr(v8::internal::r0);
66 patcher.masm()->bctrl();
67 }
68
DebugBreakSlotIsPatched(Address pc)69 bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
70 Instr current_instr = Assembler::instr_at(pc);
71 return !Assembler::IsNop(current_instr, Assembler::DEBUG_BREAK_NOP);
72 }
73
GenerateDebugBreakStub(MacroAssembler * masm,DebugBreakCallHelperMode mode)74 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
75 DebugBreakCallHelperMode mode) {
76 __ RecordComment("Debug break");
77 {
78 FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
79
80 // Load padding words on stack.
81 __ LoadSmiLiteral(ip, Smi::FromInt(LiveEdit::kFramePaddingValue));
82 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
83 __ push(ip);
84 }
85 __ LoadSmiLiteral(ip, Smi::FromInt(LiveEdit::kFramePaddingInitialSize));
86 __ push(ip);
87
88 // Push arguments for DebugBreak call.
89 if (mode == SAVE_RESULT_REGISTER) {
90 // Break on return.
91 __ push(r3);
92 } else {
93 // Non-return breaks.
94 __ Push(masm->isolate()->factory()->the_hole_value());
95 }
96 __ mov(r3, Operand(1));
97 __ mov(r4,
98 Operand(ExternalReference(
99 Runtime::FunctionForId(Runtime::kDebugBreak), masm->isolate())));
100
101 CEntryStub ceb(masm->isolate(), 1);
102 __ CallStub(&ceb);
103
104 if (FLAG_debug_code) {
105 for (int i = 0; i < kNumJSCallerSaved; i++) {
106 Register reg = {JSCallerSavedCode(i)};
107 // Do not clobber r3 if mode is SAVE_RESULT_REGISTER. It will
108 // contain return value of the function.
109 if (!(reg.is(r3) && (mode == SAVE_RESULT_REGISTER))) {
110 __ mov(reg, Operand(kDebugZapValue));
111 }
112 }
113 }
114
115 // Don't bother removing padding bytes pushed on the stack
116 // as the frame is going to be restored right away.
117
118 // Leave the internal frame.
119 }
120
121 // Now that the break point has been handled, resume normal execution by
122 // jumping to the target address intended by the caller and that was
123 // overwritten by the address of DebugBreakXXX.
124 ExternalReference after_break_target =
125 ExternalReference::debug_after_break_target_address(masm->isolate());
126 __ mov(ip, Operand(after_break_target));
127 __ LoadP(ip, MemOperand(ip));
128 __ JumpToJSEntry(ip);
129 }
130
131
GenerateFrameDropperLiveEdit(MacroAssembler * masm)132 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
133 // Load the function pointer off of our current stack frame.
134 __ LoadP(r4, MemOperand(fp, FrameDropperFrameConstants::kFunctionOffset));
135
136 // Pop return address and frame
137 __ LeaveFrame(StackFrame::INTERNAL);
138
139 ParameterCount dummy(0);
140 __ FloodFunctionIfStepping(r4, no_reg, dummy, dummy);
141
142 // Load context from the function.
143 __ LoadP(cp, FieldMemOperand(r4, JSFunction::kContextOffset));
144
145 // Clear new.target as a safety measure.
146 __ LoadRoot(r6, Heap::kUndefinedValueRootIndex);
147
148 // Get function code.
149 __ LoadP(ip, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
150 __ LoadP(ip, FieldMemOperand(ip, SharedFunctionInfo::kCodeOffset));
151 __ addi(ip, ip, Operand(Code::kHeaderSize - kHeapObjectTag));
152
153 // Re-run JSFunction, r4 is function, cp is context.
154 __ Jump(ip);
155 }
156
157
158 const bool LiveEdit::kFrameDropperSupported = true;
159
160 #undef __
161 } // namespace internal
162 } // namespace v8
163
164 #endif // V8_TARGET_ARCH_PPC
165