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 #include "src/v8.h"
6
7 #if V8_TARGET_ARCH_ARM
8
9 #include "src/codegen.h"
10 #include "src/debug.h"
11
12 namespace v8 {
13 namespace internal {
14
IsDebugBreakAtReturn()15 bool BreakLocationIterator::IsDebugBreakAtReturn() {
16 return Debug::IsDebugBreakAtReturn(rinfo());
17 }
18
19
SetDebugBreakAtReturn()20 void BreakLocationIterator::SetDebugBreakAtReturn() {
21 // Patch the code changing the return from JS function sequence from
22 // mov sp, fp
23 // ldmia sp!, {fp, lr}
24 // add sp, sp, #4
25 // bx lr
26 // to a call to the debug break return code.
27 // ldr ip, [pc, #0]
28 // blx ip
29 // <debug break return code entry point address>
30 // bkpt 0
31 CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
32 patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
33 patcher.masm()->blx(v8::internal::ip);
34 patcher.Emit(
35 debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry());
36 patcher.masm()->bkpt(0);
37 }
38
39
40 // Restore the JS frame exit code.
ClearDebugBreakAtReturn()41 void BreakLocationIterator::ClearDebugBreakAtReturn() {
42 rinfo()->PatchCode(original_rinfo()->pc(),
43 Assembler::kJSReturnSequenceInstructions);
44 }
45
46
47 // A debug break in the frame exit code is identified by the JS frame exit code
48 // having been patched with a call instruction.
IsDebugBreakAtReturn(RelocInfo * rinfo)49 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
50 DCHECK(RelocInfo::IsJSReturn(rinfo->rmode()));
51 return rinfo->IsPatchedReturnSequence();
52 }
53
54
IsDebugBreakAtSlot()55 bool BreakLocationIterator::IsDebugBreakAtSlot() {
56 DCHECK(IsDebugBreakSlot());
57 // Check whether the debug break slot instructions have been patched.
58 return rinfo()->IsPatchedDebugBreakSlotSequence();
59 }
60
61
SetDebugBreakAtSlot()62 void BreakLocationIterator::SetDebugBreakAtSlot() {
63 DCHECK(IsDebugBreakSlot());
64 // Patch the code changing the debug break slot code from
65 // mov r2, r2
66 // mov r2, r2
67 // mov r2, r2
68 // to a call to the debug break slot code.
69 // ldr ip, [pc, #0]
70 // blx ip
71 // <debug break slot code entry point address>
72 CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
73 patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
74 patcher.masm()->blx(v8::internal::ip);
75 patcher.Emit(
76 debug_info_->GetIsolate()->builtins()->Slot_DebugBreak()->entry());
77 }
78
79
ClearDebugBreakAtSlot()80 void BreakLocationIterator::ClearDebugBreakAtSlot() {
81 DCHECK(IsDebugBreakSlot());
82 rinfo()->PatchCode(original_rinfo()->pc(),
83 Assembler::kDebugBreakSlotInstructions);
84 }
85
86
87 #define __ ACCESS_MASM(masm)
88
89
Generate_DebugBreakCallHelper(MacroAssembler * masm,RegList object_regs,RegList non_object_regs)90 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
91 RegList object_regs,
92 RegList non_object_regs) {
93 {
94 FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
95
96 // Load padding words on stack.
97 __ mov(ip, Operand(Smi::FromInt(LiveEdit::kFramePaddingValue)));
98 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
99 __ push(ip);
100 }
101 __ mov(ip, Operand(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
102 __ push(ip);
103
104 // Store the registers containing live values on the expression stack to
105 // make sure that these are correctly updated during GC. Non object values
106 // are stored as a smi causing it to be untouched by GC.
107 DCHECK((object_regs & ~kJSCallerSaved) == 0);
108 DCHECK((non_object_regs & ~kJSCallerSaved) == 0);
109 DCHECK((object_regs & non_object_regs) == 0);
110 if ((object_regs | non_object_regs) != 0) {
111 for (int i = 0; i < kNumJSCallerSaved; i++) {
112 int r = JSCallerSavedCode(i);
113 Register reg = { r };
114 if ((non_object_regs & (1 << r)) != 0) {
115 if (FLAG_debug_code) {
116 __ tst(reg, Operand(0xc0000000));
117 __ Assert(eq, kUnableToEncodeValueAsSmi);
118 }
119 __ SmiTag(reg);
120 }
121 }
122 __ stm(db_w, sp, object_regs | non_object_regs);
123 }
124
125 #ifdef DEBUG
126 __ RecordComment("// Calling from debug break to runtime - come in - over");
127 #endif
128 __ mov(r0, Operand::Zero()); // no arguments
129 __ mov(r1, Operand(ExternalReference::debug_break(masm->isolate())));
130
131 CEntryStub ceb(masm->isolate(), 1);
132 __ CallStub(&ceb);
133
134 // Restore the register values from the expression stack.
135 if ((object_regs | non_object_regs) != 0) {
136 __ ldm(ia_w, sp, object_regs | non_object_regs);
137 for (int i = 0; i < kNumJSCallerSaved; i++) {
138 int r = JSCallerSavedCode(i);
139 Register reg = { r };
140 if ((non_object_regs & (1 << r)) != 0) {
141 __ SmiUntag(reg);
142 }
143 if (FLAG_debug_code &&
144 (((object_regs |non_object_regs) & (1 << r)) == 0)) {
145 __ mov(reg, Operand(kDebugZapValue));
146 }
147 }
148 }
149
150 // Don't bother removing padding bytes pushed on the stack
151 // as the frame is going to be restored right away.
152
153 // Leave the internal frame.
154 }
155
156 // Now that the break point has been handled, resume normal execution by
157 // jumping to the target address intended by the caller and that was
158 // overwritten by the address of DebugBreakXXX.
159 ExternalReference after_break_target =
160 ExternalReference::debug_after_break_target_address(masm->isolate());
161 __ mov(ip, Operand(after_break_target));
162 __ ldr(ip, MemOperand(ip));
163 __ Jump(ip);
164 }
165
166
GenerateCallICStubDebugBreak(MacroAssembler * masm)167 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
168 // Register state for CallICStub
169 // ----------- S t a t e -------------
170 // -- r1 : function
171 // -- r3 : slot in feedback array (smi)
172 // -----------------------------------
173 Generate_DebugBreakCallHelper(masm, r1.bit() | r3.bit(), 0);
174 }
175
176
GenerateLoadICDebugBreak(MacroAssembler * masm)177 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
178 // Calling convention for IC load (from ic-arm.cc).
179 Register receiver = LoadDescriptor::ReceiverRegister();
180 Register name = LoadDescriptor::NameRegister();
181 Generate_DebugBreakCallHelper(masm, receiver.bit() | name.bit(), 0);
182 }
183
184
GenerateStoreICDebugBreak(MacroAssembler * masm)185 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
186 // Calling convention for IC store (from ic-arm.cc).
187 Register receiver = StoreDescriptor::ReceiverRegister();
188 Register name = StoreDescriptor::NameRegister();
189 Register value = StoreDescriptor::ValueRegister();
190 Generate_DebugBreakCallHelper(
191 masm, receiver.bit() | name.bit() | value.bit(), 0);
192 }
193
194
GenerateKeyedLoadICDebugBreak(MacroAssembler * masm)195 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
196 // Calling convention for keyed IC load (from ic-arm.cc).
197 GenerateLoadICDebugBreak(masm);
198 }
199
200
GenerateKeyedStoreICDebugBreak(MacroAssembler * masm)201 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
202 // Calling convention for IC keyed store call (from ic-arm.cc).
203 Register receiver = StoreDescriptor::ReceiverRegister();
204 Register name = StoreDescriptor::NameRegister();
205 Register value = StoreDescriptor::ValueRegister();
206 Generate_DebugBreakCallHelper(
207 masm, receiver.bit() | name.bit() | value.bit(), 0);
208 }
209
210
GenerateCompareNilICDebugBreak(MacroAssembler * masm)211 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
212 // Register state for CompareNil IC
213 // ----------- S t a t e -------------
214 // -- r0 : value
215 // -----------------------------------
216 Generate_DebugBreakCallHelper(masm, r0.bit(), 0);
217 }
218
219
GenerateReturnDebugBreak(MacroAssembler * masm)220 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
221 // In places other than IC call sites it is expected that r0 is TOS which
222 // is an object - this is not generally the case so this should be used with
223 // care.
224 Generate_DebugBreakCallHelper(masm, r0.bit(), 0);
225 }
226
227
GenerateCallFunctionStubDebugBreak(MacroAssembler * masm)228 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
229 // Register state for CallFunctionStub (from code-stubs-arm.cc).
230 // ----------- S t a t e -------------
231 // -- r1 : function
232 // -----------------------------------
233 Generate_DebugBreakCallHelper(masm, r1.bit(), 0);
234 }
235
236
GenerateCallConstructStubDebugBreak(MacroAssembler * masm)237 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
238 // Calling convention for CallConstructStub (from code-stubs-arm.cc)
239 // ----------- S t a t e -------------
240 // -- r0 : number of arguments (not smi)
241 // -- r1 : constructor function
242 // -----------------------------------
243 Generate_DebugBreakCallHelper(masm, r1.bit(), r0.bit());
244 }
245
246
GenerateCallConstructStubRecordDebugBreak(MacroAssembler * masm)247 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
248 MacroAssembler* masm) {
249 // Calling convention for CallConstructStub (from code-stubs-arm.cc)
250 // ----------- S t a t e -------------
251 // -- r0 : number of arguments (not smi)
252 // -- r1 : constructor function
253 // -- r2 : feedback array
254 // -- r3 : feedback slot (smi)
255 // -----------------------------------
256 Generate_DebugBreakCallHelper(masm, r1.bit() | r2.bit() | r3.bit(), r0.bit());
257 }
258
259
GenerateSlot(MacroAssembler * masm)260 void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
261 // Generate enough nop's to make space for a call instruction. Avoid emitting
262 // the constant pool in the debug break slot code.
263 Assembler::BlockConstPoolScope block_const_pool(masm);
264 Label check_codesize;
265 __ bind(&check_codesize);
266 __ RecordDebugBreakSlot();
267 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
268 __ nop(MacroAssembler::DEBUG_BREAK_NOP);
269 }
270 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
271 masm->InstructionsGeneratedSince(&check_codesize));
272 }
273
274
GenerateSlotDebugBreak(MacroAssembler * masm)275 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) {
276 // In the places where a debug break slot is inserted no registers can contain
277 // object pointers.
278 Generate_DebugBreakCallHelper(masm, 0, 0);
279 }
280
281
GeneratePlainReturnLiveEdit(MacroAssembler * masm)282 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
283 __ Ret();
284 }
285
286
GenerateFrameDropperLiveEdit(MacroAssembler * masm)287 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
288 ExternalReference restarter_frame_function_slot =
289 ExternalReference::debug_restarter_frame_function_pointer_address(
290 masm->isolate());
291 __ mov(ip, Operand(restarter_frame_function_slot));
292 __ mov(r1, Operand::Zero());
293 __ str(r1, MemOperand(ip, 0));
294
295 // Load the function pointer off of our current stack frame.
296 __ ldr(r1, MemOperand(fp,
297 StandardFrameConstants::kConstantPoolOffset - kPointerSize));
298
299 // Pop return address, frame and constant pool pointer (if
300 // FLAG_enable_ool_constant_pool).
301 __ LeaveFrame(StackFrame::INTERNAL);
302
303 { ConstantPoolUnavailableScope constant_pool_unavailable(masm);
304 // Load context from the function.
305 __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
306
307 // Get function code.
308 __ ldr(ip, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
309 __ ldr(ip, FieldMemOperand(ip, SharedFunctionInfo::kCodeOffset));
310 __ add(ip, ip, Operand(Code::kHeaderSize - kHeapObjectTag));
311
312 // Re-run JSFunction, r1 is function, cp is context.
313 __ Jump(ip);
314 }
315 }
316
317
318 const bool LiveEdit::kFrameDropperSupported = true;
319
320 #undef __
321
322 } } // namespace v8::internal
323
324 #endif // V8_TARGET_ARCH_ARM
325