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_MIPS
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 instrucntions we emit.
33 DCHECK(Assembler::kJSReturnSequenceInstructions == 7);
34 CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
35 // li and Call pseudo-instructions emit two instructions each.
36 patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int32_t>(
37 debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry())));
38 patcher.masm()->Call(v8::internal::t9);
39 patcher.masm()->nop();
40 patcher.masm()->nop();
41 patcher.masm()->nop();
42
43 // TODO(mips): Open issue about using breakpoint instruction instead of nops.
44 // patcher.masm()->bkpt(0);
45 }
46
47
48 // Restore the JS frame exit code.
ClearDebugBreakAtReturn()49 void BreakLocationIterator::ClearDebugBreakAtReturn() {
50 rinfo()->PatchCode(original_rinfo()->pc(),
51 Assembler::kJSReturnSequenceInstructions);
52 }
53
54
55 // A debug break in the exit code is identified by the JS frame exit code
56 // having been patched with li/call psuedo-instrunction (liu/ori/jalr).
IsDebugBreakAtReturn(RelocInfo * rinfo)57 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
58 DCHECK(RelocInfo::IsJSReturn(rinfo->rmode()));
59 return rinfo->IsPatchedReturnSequence();
60 }
61
62
IsDebugBreakAtSlot()63 bool BreakLocationIterator::IsDebugBreakAtSlot() {
64 DCHECK(IsDebugBreakSlot());
65 // Check whether the debug break slot instructions have been patched.
66 return rinfo()->IsPatchedDebugBreakSlotSequence();
67 }
68
69
SetDebugBreakAtSlot()70 void BreakLocationIterator::SetDebugBreakAtSlot() {
71 DCHECK(IsDebugBreakSlot());
72 // Patch the code changing the debug break slot code from:
73 // nop(DEBUG_BREAK_NOP) - nop(1) is sll(zero_reg, zero_reg, 1)
74 // nop(DEBUG_BREAK_NOP)
75 // nop(DEBUG_BREAK_NOP)
76 // nop(DEBUG_BREAK_NOP)
77 // to a call to the debug break slot code.
78 // li t9, address (lui t9 / ori t9 instruction pair)
79 // call t9 (jalr t9 / nop instruction pair)
80 CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
81 patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int32_t>(
82 debug_info_->GetIsolate()->builtins()->Slot_DebugBreak()->entry())));
83 patcher.masm()->Call(v8::internal::t9);
84 }
85
86
ClearDebugBreakAtSlot()87 void BreakLocationIterator::ClearDebugBreakAtSlot() {
88 DCHECK(IsDebugBreakSlot());
89 rinfo()->PatchCode(original_rinfo()->pc(),
90 Assembler::kDebugBreakSlotInstructions);
91 }
92
93
94 #define __ ACCESS_MASM(masm)
95
96
97
Generate_DebugBreakCallHelper(MacroAssembler * masm,RegList object_regs,RegList non_object_regs)98 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
99 RegList object_regs,
100 RegList non_object_regs) {
101 {
102 FrameScope scope(masm, StackFrame::INTERNAL);
103
104 // Load padding words on stack.
105 __ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingValue)));
106 __ Subu(sp, sp,
107 Operand(kPointerSize * LiveEdit::kFramePaddingInitialSize));
108 for (int i = LiveEdit::kFramePaddingInitialSize - 1; i >= 0; i--) {
109 __ sw(at, MemOperand(sp, kPointerSize * i));
110 }
111 __ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
112 __ push(at);
113
114 // Store the registers containing live values on the expression stack to
115 // make sure that these are correctly updated during GC. Non object values
116 // are stored as a smi causing it to be untouched by GC.
117 DCHECK((object_regs & ~kJSCallerSaved) == 0);
118 DCHECK((non_object_regs & ~kJSCallerSaved) == 0);
119 DCHECK((object_regs & non_object_regs) == 0);
120 if ((object_regs | non_object_regs) != 0) {
121 for (int i = 0; i < kNumJSCallerSaved; i++) {
122 int r = JSCallerSavedCode(i);
123 Register reg = { r };
124 if ((non_object_regs & (1 << r)) != 0) {
125 if (FLAG_debug_code) {
126 __ And(at, reg, 0xc0000000);
127 __ Assert(eq, kUnableToEncodeValueAsSmi, at, Operand(zero_reg));
128 }
129 __ sll(reg, reg, kSmiTagSize);
130 }
131 }
132 __ MultiPush(object_regs | non_object_regs);
133 }
134
135 #ifdef DEBUG
136 __ RecordComment("// Calling from debug break to runtime - come in - over");
137 #endif
138 __ PrepareCEntryArgs(0); // No arguments.
139 __ PrepareCEntryFunction(ExternalReference::debug_break(masm->isolate()));
140
141 CEntryStub ceb(masm->isolate(), 1);
142 __ CallStub(&ceb);
143
144 // Restore the register values from the expression stack.
145 if ((object_regs | non_object_regs) != 0) {
146 __ MultiPop(object_regs | non_object_regs);
147 for (int i = 0; i < kNumJSCallerSaved; i++) {
148 int r = JSCallerSavedCode(i);
149 Register reg = { r };
150 if ((non_object_regs & (1 << r)) != 0) {
151 __ srl(reg, reg, kSmiTagSize);
152 }
153 if (FLAG_debug_code &&
154 (((object_regs |non_object_regs) & (1 << r)) == 0)) {
155 __ li(reg, kDebugZapValue);
156 }
157 }
158 }
159
160 // Don't bother removing padding bytes pushed on the stack
161 // as the frame is going to be restored right away.
162
163 // Leave the internal frame.
164 }
165
166 // Now that the break point has been handled, resume normal execution by
167 // jumping to the target address intended by the caller and that was
168 // overwritten by the address of DebugBreakXXX.
169 ExternalReference after_break_target =
170 ExternalReference::debug_after_break_target_address(masm->isolate());
171 __ li(t9, Operand(after_break_target));
172 __ lw(t9, MemOperand(t9));
173 __ Jump(t9);
174 }
175
176
GenerateCallICStubDebugBreak(MacroAssembler * masm)177 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
178 // Register state for CallICStub
179 // ----------- S t a t e -------------
180 // -- a1 : function
181 // -- a3 : slot in feedback array (smi)
182 // -----------------------------------
183 Generate_DebugBreakCallHelper(masm, a1.bit() | a3.bit(), 0);
184 }
185
186
GenerateLoadICDebugBreak(MacroAssembler * masm)187 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
188 Register receiver = LoadDescriptor::ReceiverRegister();
189 Register name = LoadDescriptor::NameRegister();
190 Generate_DebugBreakCallHelper(masm, receiver.bit() | name.bit(), 0);
191 }
192
193
GenerateStoreICDebugBreak(MacroAssembler * masm)194 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
195 // Calling convention for IC store (from ic-mips.cc).
196 Register receiver = StoreDescriptor::ReceiverRegister();
197 Register name = StoreDescriptor::NameRegister();
198 Register value = StoreDescriptor::ValueRegister();
199 Generate_DebugBreakCallHelper(
200 masm, receiver.bit() | name.bit() | value.bit(), 0);
201 }
202
203
GenerateKeyedLoadICDebugBreak(MacroAssembler * masm)204 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
205 // Calling convention for keyed IC load (from ic-mips.cc).
206 GenerateLoadICDebugBreak(masm);
207 }
208
209
GenerateKeyedStoreICDebugBreak(MacroAssembler * masm)210 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
211 // Calling convention for IC keyed store call (from ic-mips.cc).
212 Register receiver = StoreDescriptor::ReceiverRegister();
213 Register name = StoreDescriptor::NameRegister();
214 Register value = StoreDescriptor::ValueRegister();
215 Generate_DebugBreakCallHelper(
216 masm, receiver.bit() | name.bit() | value.bit(), 0);
217 }
218
219
GenerateCompareNilICDebugBreak(MacroAssembler * masm)220 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
221 // Register state for CompareNil IC
222 // ----------- S t a t e -------------
223 // -- a0 : value
224 // -----------------------------------
225 Generate_DebugBreakCallHelper(masm, a0.bit(), 0);
226 }
227
228
GenerateReturnDebugBreak(MacroAssembler * masm)229 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
230 // In places other than IC call sites it is expected that v0 is TOS which
231 // is an object - this is not generally the case so this should be used with
232 // care.
233 Generate_DebugBreakCallHelper(masm, v0.bit(), 0);
234 }
235
236
GenerateCallFunctionStubDebugBreak(MacroAssembler * masm)237 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
238 // Register state for CallFunctionStub (from code-stubs-mips.cc).
239 // ----------- S t a t e -------------
240 // -- a1 : function
241 // -----------------------------------
242 Generate_DebugBreakCallHelper(masm, a1.bit(), 0);
243 }
244
245
GenerateCallConstructStubDebugBreak(MacroAssembler * masm)246 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
247 // Calling convention for CallConstructStub (from code-stubs-mips.cc).
248 // ----------- S t a t e -------------
249 // -- a0 : number of arguments (not smi)
250 // -- a1 : constructor function
251 // -----------------------------------
252 Generate_DebugBreakCallHelper(masm, a1.bit() , a0.bit());
253 }
254
255
GenerateCallConstructStubRecordDebugBreak(MacroAssembler * masm)256 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
257 MacroAssembler* masm) {
258 // Calling convention for CallConstructStub (from code-stubs-mips.cc).
259 // ----------- S t a t e -------------
260 // -- a0 : number of arguments (not smi)
261 // -- a1 : constructor function
262 // -- a2 : feedback array
263 // -- a3 : feedback slot (smi)
264 // -----------------------------------
265 Generate_DebugBreakCallHelper(masm, a1.bit() | a2.bit() | a3.bit(), a0.bit());
266 }
267
268
GenerateSlot(MacroAssembler * masm)269 void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
270 // Generate enough nop's to make space for a call instruction. Avoid emitting
271 // the trampoline pool in the debug break slot code.
272 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm);
273 Label check_codesize;
274 __ bind(&check_codesize);
275 __ RecordDebugBreakSlot();
276 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
277 __ nop(MacroAssembler::DEBUG_BREAK_NOP);
278 }
279 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
280 masm->InstructionsGeneratedSince(&check_codesize));
281 }
282
283
GenerateSlotDebugBreak(MacroAssembler * masm)284 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) {
285 // In the places where a debug break slot is inserted no registers can contain
286 // object pointers.
287 Generate_DebugBreakCallHelper(masm, 0, 0);
288 }
289
290
GeneratePlainReturnLiveEdit(MacroAssembler * masm)291 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
292 __ Ret();
293 }
294
295
GenerateFrameDropperLiveEdit(MacroAssembler * masm)296 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
297 ExternalReference restarter_frame_function_slot =
298 ExternalReference::debug_restarter_frame_function_pointer_address(
299 masm->isolate());
300 __ li(at, Operand(restarter_frame_function_slot));
301 __ sw(zero_reg, MemOperand(at, 0));
302
303 // We do not know our frame height, but set sp based on fp.
304 __ Subu(sp, fp, Operand(kPointerSize));
305
306 __ Pop(ra, fp, a1); // Return address, Frame, Function.
307
308 // Load context from the function.
309 __ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
310
311 // Get function code.
312 __ lw(at, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
313 __ lw(at, FieldMemOperand(at, SharedFunctionInfo::kCodeOffset));
314 __ Addu(t9, at, Operand(Code::kHeaderSize - kHeapObjectTag));
315
316 // Re-run JSFunction, a1 is function, cp is context.
317 __ Jump(t9);
318 }
319
320
321 const bool LiveEdit::kFrameDropperSupported = true;
322
323 #undef __
324
325 } } // namespace v8::internal
326
327 #endif // V8_TARGET_ARCH_MIPS
328