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
6
7 #include "src/v8.h"
8
9 #if V8_TARGET_ARCH_MIPS64
10
11 #include "src/codegen.h"
12 #include "src/debug.h"
13
14 namespace v8 {
15 namespace internal {
16
IsDebugBreakAtReturn()17 bool BreakLocationIterator::IsDebugBreakAtReturn() {
18 return Debug::IsDebugBreakAtReturn(rinfo());
19 }
20
21
SetDebugBreakAtReturn()22 void BreakLocationIterator::SetDebugBreakAtReturn() {
23 // Mips return sequence:
24 // mov sp, fp
25 // lw fp, sp(0)
26 // lw ra, sp(4)
27 // addiu sp, sp, 8
28 // addiu sp, sp, N
29 // jr ra
30 // nop (in branch delay slot)
31
32 // Make sure this constant matches the number if instructions we emit.
33 DCHECK(Assembler::kJSReturnSequenceInstructions == 7);
34 CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
35 // li and Call pseudo-instructions emit 6 + 2 instructions.
36 patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int64_t>(
37 debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry())),
38 ADDRESS_LOAD);
39 patcher.masm()->Call(v8::internal::t9);
40 // Place nop to match return sequence size.
41 patcher.masm()->nop();
42 // TODO(mips): Open issue about using breakpoint instruction instead of nops.
43 // patcher.masm()->bkpt(0);
44 }
45
46
47 // Restore the JS frame exit code.
ClearDebugBreakAtReturn()48 void BreakLocationIterator::ClearDebugBreakAtReturn() {
49 rinfo()->PatchCode(original_rinfo()->pc(),
50 Assembler::kJSReturnSequenceInstructions);
51 }
52
53
54 // A debug break in the exit code is identified by the JS frame exit code
55 // having been patched with li/call psuedo-instrunction (liu/ori/jalr).
IsDebugBreakAtReturn(RelocInfo * rinfo)56 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
57 DCHECK(RelocInfo::IsJSReturn(rinfo->rmode()));
58 return rinfo->IsPatchedReturnSequence();
59 }
60
61
IsDebugBreakAtSlot()62 bool BreakLocationIterator::IsDebugBreakAtSlot() {
63 DCHECK(IsDebugBreakSlot());
64 // Check whether the debug break slot instructions have been patched.
65 return rinfo()->IsPatchedDebugBreakSlotSequence();
66 }
67
68
SetDebugBreakAtSlot()69 void BreakLocationIterator::SetDebugBreakAtSlot() {
70 DCHECK(IsDebugBreakSlot());
71 // Patch the code changing the debug break slot code from:
72 // nop(DEBUG_BREAK_NOP) - nop(1) is sll(zero_reg, zero_reg, 1)
73 // nop(DEBUG_BREAK_NOP)
74 // nop(DEBUG_BREAK_NOP)
75 // nop(DEBUG_BREAK_NOP)
76 // nop(DEBUG_BREAK_NOP)
77 // nop(DEBUG_BREAK_NOP)
78 // to a call to the debug break slot code.
79 // li t9, address (4-instruction sequence on mips64)
80 // call t9 (jalr t9 / nop instruction pair)
81 CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
82 patcher.masm()->li(v8::internal::t9,
83 Operand(reinterpret_cast<int64_t>(
84 debug_info_->GetIsolate()->builtins()->Slot_DebugBreak()->entry())),
85 ADDRESS_LOAD);
86 patcher.masm()->Call(v8::internal::t9);
87 }
88
89
ClearDebugBreakAtSlot()90 void BreakLocationIterator::ClearDebugBreakAtSlot() {
91 DCHECK(IsDebugBreakSlot());
92 rinfo()->PatchCode(original_rinfo()->pc(),
93 Assembler::kDebugBreakSlotInstructions);
94 }
95
96
97 #define __ ACCESS_MASM(masm)
98
99
100
Generate_DebugBreakCallHelper(MacroAssembler * masm,RegList object_regs,RegList non_object_regs)101 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
102 RegList object_regs,
103 RegList non_object_regs) {
104 {
105 FrameScope scope(masm, StackFrame::INTERNAL);
106
107 // Load padding words on stack.
108 __ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingValue)));
109 __ Dsubu(sp, sp,
110 Operand(kPointerSize * LiveEdit::kFramePaddingInitialSize));
111 for (int i = LiveEdit::kFramePaddingInitialSize - 1; i >= 0; i--) {
112 __ sd(at, MemOperand(sp, kPointerSize * i));
113 }
114 __ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
115 __ push(at);
116
117
118 // TODO(plind): This needs to be revised to store pairs of smi's per
119 // the other 64-bit arch's.
120
121 // Store the registers containing live values on the expression stack to
122 // make sure that these are correctly updated during GC. Non object values
123 // are stored as a smi causing it to be untouched by GC.
124 DCHECK((object_regs & ~kJSCallerSaved) == 0);
125 DCHECK((non_object_regs & ~kJSCallerSaved) == 0);
126 DCHECK((object_regs & non_object_regs) == 0);
127 for (int i = 0; i < kNumJSCallerSaved; i++) {
128 int r = JSCallerSavedCode(i);
129 Register reg = { r };
130 if ((object_regs & (1 << r)) != 0) {
131 __ push(reg);
132 }
133 if ((non_object_regs & (1 << r)) != 0) {
134 __ PushRegisterAsTwoSmis(reg);
135 }
136 }
137
138 #ifdef DEBUG
139 __ RecordComment("// Calling from debug break to runtime - come in - over");
140 #endif
141 __ PrepareCEntryArgs(0); // No arguments.
142 __ PrepareCEntryFunction(ExternalReference::debug_break(masm->isolate()));
143
144 CEntryStub ceb(masm->isolate(), 1);
145 __ CallStub(&ceb);
146
147 // Restore the register values from the expression stack.
148 for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
149 int r = JSCallerSavedCode(i);
150 Register reg = { r };
151 if ((non_object_regs & (1 << r)) != 0) {
152 __ PopRegisterAsTwoSmis(reg, at);
153 }
154 if ((object_regs & (1 << r)) != 0) {
155 __ pop(reg);
156 }
157 if (FLAG_debug_code &&
158 (((object_regs |non_object_regs) & (1 << r)) == 0)) {
159 __ li(reg, kDebugZapValue);
160 }
161 }
162
163 // Don't bother removing padding bytes pushed on the stack
164 // as the frame is going to be restored right away.
165
166 // Leave the internal frame.
167 }
168
169 // Now that the break point has been handled, resume normal execution by
170 // jumping to the target address intended by the caller and that was
171 // overwritten by the address of DebugBreakXXX.
172 ExternalReference after_break_target =
173 ExternalReference::debug_after_break_target_address(masm->isolate());
174 __ li(t9, Operand(after_break_target));
175 __ ld(t9, MemOperand(t9));
176 __ Jump(t9);
177 }
178
179
GenerateCallICStubDebugBreak(MacroAssembler * masm)180 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
181 // Register state for CallICStub
182 // ----------- S t a t e -------------
183 // -- a1 : function
184 // -- a3 : slot in feedback array (smi)
185 // -----------------------------------
186 Generate_DebugBreakCallHelper(masm, a1.bit() | a3.bit(), 0);
187 }
188
189
GenerateLoadICDebugBreak(MacroAssembler * masm)190 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
191 Register receiver = LoadDescriptor::ReceiverRegister();
192 Register name = LoadDescriptor::NameRegister();
193 Generate_DebugBreakCallHelper(masm, receiver.bit() | name.bit(), 0);
194 }
195
196
GenerateStoreICDebugBreak(MacroAssembler * masm)197 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
198 Register receiver = StoreDescriptor::ReceiverRegister();
199 Register name = StoreDescriptor::NameRegister();
200 Register value = StoreDescriptor::ValueRegister();
201 Generate_DebugBreakCallHelper(
202 masm, receiver.bit() | name.bit() | value.bit(), 0);
203 }
204
205
GenerateKeyedLoadICDebugBreak(MacroAssembler * masm)206 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
207 // Calling convention for keyed IC load (from ic-mips64.cc).
208 GenerateLoadICDebugBreak(masm);
209 }
210
211
GenerateKeyedStoreICDebugBreak(MacroAssembler * masm)212 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
213 // Calling convention for IC keyed store call (from ic-mips64.cc).
214 Register receiver = StoreDescriptor::ReceiverRegister();
215 Register name = StoreDescriptor::NameRegister();
216 Register value = StoreDescriptor::ValueRegister();
217 Generate_DebugBreakCallHelper(
218 masm, receiver.bit() | name.bit() | value.bit(), 0);
219 }
220
221
GenerateCompareNilICDebugBreak(MacroAssembler * masm)222 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
223 // Register state for CompareNil IC
224 // ----------- S t a t e -------------
225 // -- a0 : value
226 // -----------------------------------
227 Generate_DebugBreakCallHelper(masm, a0.bit(), 0);
228 }
229
230
GenerateReturnDebugBreak(MacroAssembler * masm)231 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
232 // In places other than IC call sites it is expected that v0 is TOS which
233 // is an object - this is not generally the case so this should be used with
234 // care.
235 Generate_DebugBreakCallHelper(masm, v0.bit(), 0);
236 }
237
238
GenerateCallFunctionStubDebugBreak(MacroAssembler * masm)239 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
240 // Register state for CallFunctionStub (from code-stubs-mips.cc).
241 // ----------- S t a t e -------------
242 // -- a1 : function
243 // -----------------------------------
244 Generate_DebugBreakCallHelper(masm, a1.bit(), 0);
245 }
246
247
GenerateCallConstructStubDebugBreak(MacroAssembler * masm)248 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
249 // Calling convention for CallConstructStub (from code-stubs-mips.cc).
250 // ----------- S t a t e -------------
251 // -- a0 : number of arguments (not smi)
252 // -- a1 : constructor function
253 // -----------------------------------
254 Generate_DebugBreakCallHelper(masm, a1.bit() , a0.bit());
255 }
256
257
258
GenerateCallConstructStubRecordDebugBreak(MacroAssembler * masm)259 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
260 MacroAssembler* masm) {
261 // Calling convention for CallConstructStub (from code-stubs-mips.cc).
262 // ----------- S t a t e -------------
263 // -- a0 : number of arguments (not smi)
264 // -- a1 : constructor function
265 // -- a2 : feedback array
266 // -- a3 : feedback slot (smi)
267 // -----------------------------------
268 Generate_DebugBreakCallHelper(masm, a1.bit() | a2.bit() | a3.bit(), a0.bit());
269 }
270
271
GenerateSlot(MacroAssembler * masm)272 void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
273 // Generate enough nop's to make space for a call instruction. Avoid emitting
274 // the trampoline pool in the debug break slot code.
275 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm);
276 Label check_codesize;
277 __ bind(&check_codesize);
278 __ RecordDebugBreakSlot();
279 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
280 __ nop(MacroAssembler::DEBUG_BREAK_NOP);
281 }
282 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
283 masm->InstructionsGeneratedSince(&check_codesize));
284 }
285
286
GenerateSlotDebugBreak(MacroAssembler * masm)287 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) {
288 // In the places where a debug break slot is inserted no registers can contain
289 // object pointers.
290 Generate_DebugBreakCallHelper(masm, 0, 0);
291 }
292
293
GeneratePlainReturnLiveEdit(MacroAssembler * masm)294 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
295 __ Ret();
296 }
297
298
GenerateFrameDropperLiveEdit(MacroAssembler * masm)299 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
300 ExternalReference restarter_frame_function_slot =
301 ExternalReference::debug_restarter_frame_function_pointer_address(
302 masm->isolate());
303 __ li(at, Operand(restarter_frame_function_slot));
304 __ sw(zero_reg, MemOperand(at, 0));
305
306 // We do not know our frame height, but set sp based on fp.
307 __ Dsubu(sp, fp, Operand(kPointerSize));
308
309 __ Pop(ra, fp, a1); // Return address, Frame, Function.
310
311 // Load context from the function.
312 __ ld(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
313
314 // Get function code.
315 __ ld(at, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
316 __ ld(at, FieldMemOperand(at, SharedFunctionInfo::kCodeOffset));
317 __ Daddu(t9, at, Operand(Code::kHeaderSize - kHeapObjectTag));
318
319 // Re-run JSFunction, a1 is function, cp is context.
320 __ Jump(t9);
321 }
322
323
324 const bool LiveEdit::kFrameDropperSupported = true;
325
326 #undef __
327
328 } } // namespace v8::internal
329
330 #endif // V8_TARGET_ARCH_MIPS64
331