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1 // Copyright 2010 the V8 project authors. All rights reserved. | |
2 // Redistribution and use in source and binary forms, with or without | |
3 // modification, are permitted provided that the following conditions are | |
4 // met: | |
5 // | |
6 // * Redistributions of source code must retain the above copyright | |
7 // notice, this list of conditions and the following disclaimer. | |
8 // * Redistributions in binary form must reproduce the above | |
9 // copyright notice, this list of conditions and the following | |
10 // disclaimer in the documentation and/or other materials provided | |
11 // with the distribution. | |
12 // * Neither the name of Google Inc. nor the names of its | |
13 // contributors may be used to endorse or promote products derived | |
14 // from this software without specific prior written permission. | |
15 // | |
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
27 | |
28 | |
29 #ifndef V8_MIPS_VIRTUAL_FRAME_MIPS_H_ | |
30 #define V8_MIPS_VIRTUAL_FRAME_MIPS_H_ | |
31 | |
32 #include "register-allocator.h" | |
33 | |
34 namespace v8 { | |
35 namespace internal { | |
36 | |
37 // This dummy class is only used to create invalid virtual frames. | |
38 extern class InvalidVirtualFrameInitializer {}* kInvalidVirtualFrameInitializer; | |
39 | |
40 | |
41 // ------------------------------------------------------------------------- | |
42 // Virtual frames | |
43 // | |
44 // The virtual frame is an abstraction of the physical stack frame. It | |
45 // encapsulates the parameters, frame-allocated locals, and the expression | |
46 // stack. It supports push/pop operations on the expression stack, as well | |
47 // as random access to the expression stack elements, locals, and | |
48 // parameters. | |
49 | |
50 class VirtualFrame : public ZoneObject { | |
51 public: | |
52 class RegisterAllocationScope; | |
53 // A utility class to introduce a scope where the virtual frame is | |
54 // expected to remain spilled. The constructor spills the code | |
55 // generator's current frame, and keeps it spilled. | |
56 class SpilledScope BASE_EMBEDDED { | |
57 public: | |
58 explicit SpilledScope(VirtualFrame* frame) | |
59 : old_is_spilled_( | |
60 Isolate::Current()->is_virtual_frame_in_spilled_scope()) { | |
61 if (frame != NULL) { | |
62 if (!old_is_spilled_) { | |
63 frame->SpillAll(); | |
64 } else { | |
65 frame->AssertIsSpilled(); | |
66 } | |
67 } | |
68 Isolate::Current()->set_is_virtual_frame_in_spilled_scope(true); | |
69 } | |
70 ~SpilledScope() { | |
71 Isolate::Current()->set_is_virtual_frame_in_spilled_scope( | |
72 old_is_spilled_); | |
73 } | |
74 static bool is_spilled() { | |
75 return Isolate::Current()->is_virtual_frame_in_spilled_scope(); | |
76 } | |
77 | |
78 private: | |
79 int old_is_spilled_; | |
80 | |
81 SpilledScope() {} | |
82 | |
83 friend class RegisterAllocationScope; | |
84 }; | |
85 | |
86 class RegisterAllocationScope BASE_EMBEDDED { | |
87 public: | |
88 // A utility class to introduce a scope where the virtual frame | |
89 // is not spilled, ie. where register allocation occurs. Eventually | |
90 // when RegisterAllocationScope is ubiquitous it can be removed | |
91 // along with the (by then unused) SpilledScope class. | |
92 inline explicit RegisterAllocationScope(CodeGenerator* cgen); | |
93 inline ~RegisterAllocationScope(); | |
94 | |
95 private: | |
96 CodeGenerator* cgen_; | |
97 bool old_is_spilled_; | |
98 | |
99 RegisterAllocationScope() {} | |
100 }; | |
101 | |
102 // An illegal index into the virtual frame. | |
103 static const int kIllegalIndex = -1; | |
104 | |
105 // Construct an initial virtual frame on entry to a JS function. | |
106 inline VirtualFrame(); | |
107 | |
108 // Construct an invalid virtual frame, used by JumpTargets. | |
109 explicit inline VirtualFrame(InvalidVirtualFrameInitializer* dummy); | |
110 | |
111 // Construct a virtual frame as a clone of an existing one. | |
112 explicit inline VirtualFrame(VirtualFrame* original); | |
113 | |
114 inline CodeGenerator* cgen() const; | |
115 inline MacroAssembler* masm(); | |
116 | |
117 // The number of elements on the virtual frame. | |
118 int element_count() const { return element_count_; } | |
119 | |
120 // The height of the virtual expression stack. | |
121 inline int height() const; | |
122 | |
123 bool is_used(int num) { | |
124 switch (num) { | |
125 case 0: { // a0. | |
126 return kA0InUse[top_of_stack_state_]; | |
127 } | |
128 case 1: { // a1. | |
129 return kA1InUse[top_of_stack_state_]; | |
130 } | |
131 case 2: | |
132 case 3: | |
133 case 4: | |
134 case 5: | |
135 case 6: { // a2 to a3, t0 to t2. | |
136 ASSERT(num - kFirstAllocatedRegister < kNumberOfAllocatedRegisters); | |
137 ASSERT(num >= kFirstAllocatedRegister); | |
138 if ((register_allocation_map_ & | |
139 (1 << (num - kFirstAllocatedRegister))) == 0) { | |
140 return false; | |
141 } else { | |
142 return true; | |
143 } | |
144 } | |
145 default: { | |
146 ASSERT(num < kFirstAllocatedRegister || | |
147 num >= kFirstAllocatedRegister + kNumberOfAllocatedRegisters); | |
148 return false; | |
149 } | |
150 } | |
151 } | |
152 | |
153 // Add extra in-memory elements to the top of the frame to match an actual | |
154 // frame (eg, the frame after an exception handler is pushed). No code is | |
155 // emitted. | |
156 void Adjust(int count); | |
157 | |
158 // Forget elements from the top of the frame to match an actual frame (eg, | |
159 // the frame after a runtime call). No code is emitted except to bring the | |
160 // frame to a spilled state. | |
161 void Forget(int count); | |
162 | |
163 | |
164 // Spill all values from the frame to memory. | |
165 void SpillAll(); | |
166 | |
167 void AssertIsSpilled() const { | |
168 ASSERT(top_of_stack_state_ == NO_TOS_REGISTERS); | |
169 ASSERT(register_allocation_map_ == 0); | |
170 } | |
171 | |
172 void AssertIsNotSpilled() { | |
173 ASSERT(!SpilledScope::is_spilled()); | |
174 } | |
175 | |
176 // Spill all occurrences of a specific register from the frame. | |
177 void Spill(Register reg) { | |
178 UNIMPLEMENTED(); | |
179 } | |
180 | |
181 // Spill all occurrences of an arbitrary register if possible. Return the | |
182 // register spilled or no_reg if it was not possible to free any register | |
183 // (ie, they all have frame-external references). Unimplemented. | |
184 Register SpillAnyRegister(); | |
185 | |
186 // Make this virtual frame have a state identical to an expected virtual | |
187 // frame. As a side effect, code may be emitted to make this frame match | |
188 // the expected one. | |
189 void MergeTo(const VirtualFrame* expected, | |
190 Condition cond = al, | |
191 Register r1 = no_reg, | |
192 const Operand& r2 = Operand(no_reg)); | |
193 | |
194 void MergeTo(VirtualFrame* expected, | |
195 Condition cond = al, | |
196 Register r1 = no_reg, | |
197 const Operand& r2 = Operand(no_reg)); | |
198 | |
199 // Checks whether this frame can be branched to by the other frame. | |
200 bool IsCompatibleWith(const VirtualFrame* other) const { | |
201 return (tos_known_smi_map_ & (~other->tos_known_smi_map_)) == 0; | |
202 } | |
203 | |
204 inline void ForgetTypeInfo() { | |
205 tos_known_smi_map_ = 0; | |
206 } | |
207 | |
208 // Detach a frame from its code generator, perhaps temporarily. This | |
209 // tells the register allocator that it is free to use frame-internal | |
210 // registers. Used when the code generator's frame is switched from this | |
211 // one to NULL by an unconditional jump. | |
212 void DetachFromCodeGenerator() { | |
213 } | |
214 | |
215 // (Re)attach a frame to its code generator. This informs the register | |
216 // allocator that the frame-internal register references are active again. | |
217 // Used when a code generator's frame is switched from NULL to this one by | |
218 // binding a label. | |
219 void AttachToCodeGenerator() { | |
220 } | |
221 | |
222 // Emit code for the physical JS entry and exit frame sequences. After | |
223 // calling Enter, the virtual frame is ready for use; and after calling | |
224 // Exit it should not be used. Note that Enter does not allocate space in | |
225 // the physical frame for storing frame-allocated locals. | |
226 void Enter(); | |
227 void Exit(); | |
228 | |
229 // Prepare for returning from the frame by elements in the virtual frame. | |
230 // This avoids generating unnecessary merge code when jumping to the shared | |
231 // return site. No spill code emitted. Value to return should be in v0. | |
232 inline void PrepareForReturn(); | |
233 | |
234 // Number of local variables after when we use a loop for allocating. | |
235 static const int kLocalVarBound = 5; | |
236 | |
237 // Allocate and initialize the frame-allocated locals. | |
238 void AllocateStackSlots(); | |
239 | |
240 // The current top of the expression stack as an assembly operand. | |
241 MemOperand Top() { | |
242 AssertIsSpilled(); | |
243 return MemOperand(sp, 0); | |
244 } | |
245 | |
246 // An element of the expression stack as an assembly operand. | |
247 MemOperand ElementAt(int index) { | |
248 int adjusted_index = index - kVirtualElements[top_of_stack_state_]; | |
249 ASSERT(adjusted_index >= 0); | |
250 return MemOperand(sp, adjusted_index * kPointerSize); | |
251 } | |
252 | |
253 bool KnownSmiAt(int index) { | |
254 if (index >= kTOSKnownSmiMapSize) return false; | |
255 return (tos_known_smi_map_ & (1 << index)) != 0; | |
256 } | |
257 // A frame-allocated local as an assembly operand. | |
258 inline MemOperand LocalAt(int index); | |
259 | |
260 // Push the address of the receiver slot on the frame. | |
261 void PushReceiverSlotAddress(); | |
262 | |
263 // The function frame slot. | |
264 MemOperand Function() { return MemOperand(fp, kFunctionOffset); } | |
265 | |
266 // The context frame slot. | |
267 MemOperand Context() { return MemOperand(fp, kContextOffset); } | |
268 | |
269 // A parameter as an assembly operand. | |
270 inline MemOperand ParameterAt(int index); | |
271 | |
272 // The receiver frame slot. | |
273 inline MemOperand Receiver(); | |
274 | |
275 // Push a try-catch or try-finally handler on top of the virtual frame. | |
276 void PushTryHandler(HandlerType type); | |
277 | |
278 // Call stub given the number of arguments it expects on (and | |
279 // removes from) the stack. | |
280 inline void CallStub(CodeStub* stub, int arg_count); | |
281 | |
282 // Call JS function from top of the stack with arguments | |
283 // taken from the stack. | |
284 void CallJSFunction(int arg_count); | |
285 | |
286 // Call runtime given the number of arguments expected on (and | |
287 // removed from) the stack. | |
288 void CallRuntime(const Runtime::Function* f, int arg_count); | |
289 void CallRuntime(Runtime::FunctionId id, int arg_count); | |
290 | |
291 #ifdef ENABLE_DEBUGGER_SUPPORT | |
292 void DebugBreak(); | |
293 #endif | |
294 | |
295 // Invoke builtin given the number of arguments it expects on (and | |
296 // removes from) the stack. | |
297 void InvokeBuiltin(Builtins::JavaScript id, | |
298 InvokeFlag flag, | |
299 int arg_count); | |
300 | |
301 // Call load IC. Receiver is on the stack and is consumed. Result is returned | |
302 // in v0. | |
303 void CallLoadIC(Handle<String> name, RelocInfo::Mode mode); | |
304 | |
305 // Call store IC. If the load is contextual, value is found on top of the | |
306 // frame. If not, value and receiver are on the frame. Both are consumed. | |
307 // Result is returned in v0. | |
308 void CallStoreIC(Handle<String> name, bool is_contextual); | |
309 | |
310 // Call keyed load IC. Key and receiver are on the stack. Both are consumed. | |
311 // Result is returned in v0. | |
312 void CallKeyedLoadIC(); | |
313 | |
314 // Call keyed store IC. Value, key and receiver are on the stack. All three | |
315 // are consumed. Result is returned in v0 (and a0). | |
316 void CallKeyedStoreIC(); | |
317 | |
318 // Call into an IC stub given the number of arguments it removes | |
319 // from the stack. Register arguments to the IC stub are implicit, | |
320 // and depend on the type of IC stub. | |
321 void CallCodeObject(Handle<Code> ic, | |
322 RelocInfo::Mode rmode, | |
323 int dropped_args); | |
324 | |
325 // Drop a number of elements from the top of the expression stack. May | |
326 // emit code to affect the physical frame. Does not clobber any registers | |
327 // excepting possibly the stack pointer. | |
328 void Drop(int count); | |
329 | |
330 // Drop one element. | |
331 void Drop() { Drop(1); } | |
332 | |
333 // Pop an element from the top of the expression stack. Discards | |
334 // the result. | |
335 void Pop(); | |
336 | |
337 // Pop an element from the top of the expression stack. The register | |
338 // will be one normally used for the top of stack register allocation | |
339 // so you can't hold on to it if you push on the stack. | |
340 Register PopToRegister(Register but_not_to_this_one = no_reg); | |
341 | |
342 // Look at the top of the stack. The register returned is aliased and | |
343 // must be copied to a scratch register before modification. | |
344 Register Peek(); | |
345 | |
346 // Look at the value beneath the top of the stack. The register returned is | |
347 // aliased and must be copied to a scratch register before modification. | |
348 Register Peek2(); | |
349 | |
350 // Duplicate the top of stack. | |
351 void Dup(); | |
352 | |
353 // Duplicate the two elements on top of stack. | |
354 void Dup2(); | |
355 | |
356 // Flushes all registers, but it puts a copy of the top-of-stack in a0. | |
357 void SpillAllButCopyTOSToA0(); | |
358 | |
359 // Flushes all registers, but it puts a copy of the top-of-stack in a1. | |
360 void SpillAllButCopyTOSToA1(); | |
361 | |
362 // Flushes all registers, but it puts a copy of the top-of-stack in a1 | |
363 // and the next value on the stack in a0. | |
364 void SpillAllButCopyTOSToA1A0(); | |
365 | |
366 // Pop and save an element from the top of the expression stack and | |
367 // emit a corresponding pop instruction. | |
368 void EmitPop(Register reg); | |
369 // Same but for multiple registers | |
370 void EmitMultiPop(RegList regs); | |
371 void EmitMultiPopReversed(RegList regs); | |
372 | |
373 | |
374 // Takes the top two elements and puts them in a0 (top element) and a1 | |
375 // (second element). | |
376 void PopToA1A0(); | |
377 | |
378 // Takes the top element and puts it in a1. | |
379 void PopToA1(); | |
380 | |
381 // Takes the top element and puts it in a0. | |
382 void PopToA0(); | |
383 | |
384 // Push an element on top of the expression stack and emit a | |
385 // corresponding push instruction. | |
386 void EmitPush(Register reg, TypeInfo type_info = TypeInfo::Unknown()); | |
387 void EmitPush(Operand operand, TypeInfo type_info = TypeInfo::Unknown()); | |
388 void EmitPush(MemOperand operand, TypeInfo type_info = TypeInfo::Unknown()); | |
389 void EmitPushRoot(Heap::RootListIndex index); | |
390 | |
391 // Overwrite the nth thing on the stack. If the nth position is in a | |
392 // register then this turns into a Move, otherwise an sw. Afterwards | |
393 // you can still use the register even if it is a register that can be | |
394 // used for TOS (a0 or a1). | |
395 void SetElementAt(Register reg, int this_far_down); | |
396 | |
397 // Get a register which is free and which must be immediately used to | |
398 // push on the top of the stack. | |
399 Register GetTOSRegister(); | |
400 | |
401 // Same but for multiple registers. | |
402 void EmitMultiPush(RegList regs); | |
403 void EmitMultiPushReversed(RegList regs); | |
404 | |
405 static Register scratch0() { return t4; } | |
406 static Register scratch1() { return t5; } | |
407 static Register scratch2() { return t6; } | |
408 | |
409 private: | |
410 static const int kLocal0Offset = JavaScriptFrameConstants::kLocal0Offset; | |
411 static const int kFunctionOffset = JavaScriptFrameConstants::kFunctionOffset; | |
412 static const int kContextOffset = StandardFrameConstants::kContextOffset; | |
413 | |
414 static const int kHandlerSize = StackHandlerConstants::kSize / kPointerSize; | |
415 static const int kPreallocatedElements = 5 + 8; // 8 expression stack slots. | |
416 | |
417 // 5 states for the top of stack, which can be in memory or in a0 and a1. | |
418 enum TopOfStack { NO_TOS_REGISTERS, A0_TOS, A1_TOS, A1_A0_TOS, A0_A1_TOS, | |
419 TOS_STATES}; | |
420 static const int kMaxTOSRegisters = 2; | |
421 | |
422 static const bool kA0InUse[TOS_STATES]; | |
423 static const bool kA1InUse[TOS_STATES]; | |
424 static const int kVirtualElements[TOS_STATES]; | |
425 static const TopOfStack kStateAfterPop[TOS_STATES]; | |
426 static const TopOfStack kStateAfterPush[TOS_STATES]; | |
427 static const Register kTopRegister[TOS_STATES]; | |
428 static const Register kBottomRegister[TOS_STATES]; | |
429 | |
430 // We allocate up to 5 locals in registers. | |
431 static const int kNumberOfAllocatedRegisters = 5; | |
432 // r2 to r6 are allocated to locals. | |
433 static const int kFirstAllocatedRegister = 2; | |
434 | |
435 static const Register kAllocatedRegisters[kNumberOfAllocatedRegisters]; | |
436 | |
437 static Register AllocatedRegister(int r) { | |
438 ASSERT(r >= 0 && r < kNumberOfAllocatedRegisters); | |
439 return kAllocatedRegisters[r]; | |
440 } | |
441 | |
442 // The number of elements on the stack frame. | |
443 int element_count_; | |
444 TopOfStack top_of_stack_state_:3; | |
445 int register_allocation_map_:kNumberOfAllocatedRegisters; | |
446 static const int kTOSKnownSmiMapSize = 4; | |
447 unsigned tos_known_smi_map_:kTOSKnownSmiMapSize; | |
448 | |
449 // The index of the element that is at the processor's stack pointer | |
450 // (the sp register). For now since everything is in memory it is given | |
451 // by the number of elements on the not-very-virtual stack frame. | |
452 int stack_pointer() { return element_count_ - 1; } | |
453 | |
454 // The number of frame-allocated locals and parameters respectively. | |
455 inline int parameter_count() const; | |
456 inline int local_count() const; | |
457 | |
458 // The index of the element that is at the processor's frame pointer | |
459 // (the fp register). The parameters, receiver, function, and context | |
460 // are below the frame pointer. | |
461 inline int frame_pointer() const; | |
462 | |
463 // The index of the first parameter. The receiver lies below the first | |
464 // parameter. | |
465 int param0_index() { return 1; } | |
466 | |
467 // The index of the context slot in the frame. It is immediately | |
468 // below the frame pointer. | |
469 inline int context_index(); | |
470 | |
471 // The index of the function slot in the frame. It is below the frame | |
472 // pointer and context slot. | |
473 inline int function_index(); | |
474 | |
475 // The index of the first local. Between the frame pointer and the | |
476 // locals lies the return address. | |
477 inline int local0_index() const; | |
478 | |
479 // The index of the base of the expression stack. | |
480 inline int expression_base_index() const; | |
481 | |
482 // Convert a frame index into a frame pointer relative offset into the | |
483 // actual stack. | |
484 inline int fp_relative(int index); | |
485 | |
486 // Spill all elements in registers. Spill the top spilled_args elements | |
487 // on the frame. Sync all other frame elements. | |
488 // Then drop dropped_args elements from the virtual frame, to match | |
489 // the effect of an upcoming call that will drop them from the stack. | |
490 void PrepareForCall(int spilled_args, int dropped_args); | |
491 | |
492 // If all top-of-stack registers are in use then the lowest one is pushed | |
493 // onto the physical stack and made free. | |
494 void EnsureOneFreeTOSRegister(); | |
495 | |
496 // Emit instructions to get the top of stack state from where we are to where | |
497 // we want to be. | |
498 void MergeTOSTo(TopOfStack expected_state, | |
499 Condition cond = al, | |
500 Register r1 = no_reg, | |
501 const Operand& r2 = Operand(no_reg)); | |
502 | |
503 inline bool Equals(const VirtualFrame* other); | |
504 | |
505 inline void LowerHeight(int count) { | |
506 element_count_ -= count; | |
507 if (count >= kTOSKnownSmiMapSize) { | |
508 tos_known_smi_map_ = 0; | |
509 } else { | |
510 tos_known_smi_map_ >>= count; | |
511 } | |
512 } | |
513 | |
514 inline void RaiseHeight(int count, unsigned known_smi_map = 0) { | |
515 ASSERT(known_smi_map < (1u << count)); | |
516 element_count_ += count; | |
517 if (count >= kTOSKnownSmiMapSize) { | |
518 tos_known_smi_map_ = known_smi_map; | |
519 } else { | |
520 tos_known_smi_map_ = ((tos_known_smi_map_ << count) | known_smi_map); | |
521 } | |
522 } | |
523 friend class JumpTarget; | |
524 }; | |
525 | |
526 | |
527 } } // namespace v8::internal | |
528 | |
529 #endif // V8_MIPS_VIRTUAL_FRAME_MIPS_H_ | |
530 | |
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