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1 // Copyright 2009 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 #ifndef V8_VIRTUAL_FRAME_ARM_H_ | |
29 #define V8_VIRTUAL_FRAME_ARM_H_ | |
30 | |
31 #include "register-allocator.h" | |
32 | |
33 namespace v8 { namespace internal { | |
34 | |
35 // ------------------------------------------------------------------------- | |
36 // Virtual frames | |
37 // | |
38 // The virtual frame is an abstraction of the physical stack frame. It | |
39 // encapsulates the parameters, frame-allocated locals, and the expression | |
40 // stack. It supports push/pop operations on the expression stack, as well | |
41 // as random access to the expression stack elements, locals, and | |
42 // parameters. | |
43 | |
44 class VirtualFrame : public Malloced { | |
45 public: | |
46 // A utility class to introduce a scope where the virtual frame is | |
47 // expected to remain spilled. The constructor spills the code | |
48 // generator's current frame, but no attempt is made to require it | |
49 // to stay spilled. It is intended as documentation while the code | |
50 // generator is being transformed. | |
51 class SpilledScope BASE_EMBEDDED { | |
52 public: | |
53 explicit SpilledScope(CodeGenerator* cgen); | |
54 | |
55 ~SpilledScope(); | |
56 | |
57 private: | |
58 CodeGenerator* cgen_; | |
59 bool previous_state_; | |
60 }; | |
61 | |
62 // An illegal index into the virtual frame. | |
63 static const int kIllegalIndex = -1; | |
64 | |
65 // Construct an initial virtual frame on entry to a JS function. | |
66 explicit VirtualFrame(CodeGenerator* cgen); | |
67 | |
68 // Construct a virtual frame as a clone of an existing one. | |
69 explicit VirtualFrame(VirtualFrame* original); | |
70 | |
71 // Create a duplicate of an existing valid frame element. | |
72 FrameElement CopyElementAt(int index); | |
73 | |
74 // The height of the virtual expression stack. | |
75 int height() const { | |
76 return elements_.length() - expression_base_index(); | |
77 } | |
78 | |
79 int register_index(Register reg) { | |
80 return register_locations_[reg.code()]; | |
81 } | |
82 | |
83 bool is_used(int reg_code) { | |
84 return register_locations_[reg_code] != kIllegalIndex; | |
85 } | |
86 | |
87 bool is_used(Register reg) { | |
88 return is_used(reg.code()); | |
89 } | |
90 | |
91 // Add extra in-memory elements to the top of the frame to match an actual | |
92 // frame (eg, the frame after an exception handler is pushed). No code is | |
93 // emitted. | |
94 void Adjust(int count); | |
95 | |
96 // Forget elements from the top of the frame to match an actual frame (eg, | |
97 // the frame after a runtime call). No code is emitted. | |
98 void Forget(int count); | |
99 | |
100 // Forget count elements from the top of the frame without adjusting | |
101 // the stack pointer downward. This is used, for example, before | |
102 // merging frames at break, continue, and return targets. | |
103 void ForgetElements(int count); | |
104 | |
105 // Spill all values from the frame to memory. | |
106 void SpillAll(); | |
107 | |
108 // Spill all occurrences of a specific register from the frame. | |
109 void Spill(Register reg); | |
110 | |
111 // Spill all occurrences of an arbitrary register if possible. Return the | |
112 // register spilled or no_reg if it was not possible to free any register | |
113 // (ie, they all have frame-external references). | |
114 Register SpillAnyRegister(); | |
115 | |
116 // Prepare this virtual frame for merging to an expected frame by | |
117 // performing some state changes that do not require generating | |
118 // code. It is guaranteed that no code will be generated. | |
119 void PrepareMergeTo(VirtualFrame* expected); | |
120 | |
121 // Make this virtual frame have a state identical to an expected virtual | |
122 // frame. As a side effect, code may be emitted to make this frame match | |
123 // the expected one. | |
124 void MergeTo(VirtualFrame* expected); | |
125 | |
126 // Detach a frame from its code generator, perhaps temporarily. This | |
127 // tells the register allocator that it is free to use frame-internal | |
128 // registers. Used when the code generator's frame is switched from this | |
129 // one to NULL by an unconditional jump. | |
130 void DetachFromCodeGenerator(); | |
131 | |
132 // (Re)attach a frame to its code generator. This informs the register | |
133 // allocator that the frame-internal register references are active again. | |
134 // Used when a code generator's frame is switched from NULL to this one by | |
135 // binding a label. | |
136 void AttachToCodeGenerator(); | |
137 | |
138 // Emit code for the physical JS entry and exit frame sequences. After | |
139 // calling Enter, the virtual frame is ready for use; and after calling | |
140 // Exit it should not be used. Note that Enter does not allocate space in | |
141 // the physical frame for storing frame-allocated locals. | |
142 void Enter(); | |
143 void Exit(); | |
144 | |
145 // Prepare for returning from the frame by spilling locals and | |
146 // dropping all non-locals elements in the virtual frame. This | |
147 // avoids generating unnecessary merge code when jumping to the | |
148 // shared return site. Emits code for spills. | |
149 void PrepareForReturn(); | |
150 | |
151 // Allocate and initialize the frame-allocated locals. | |
152 void AllocateStackSlots(int count); | |
153 | |
154 // The current top of the expression stack as an assembly operand. | |
155 MemOperand Top() const { return MemOperand(sp, 0); } | |
156 | |
157 // An element of the expression stack as an assembly operand. | |
158 MemOperand ElementAt(int index) const { | |
159 return MemOperand(sp, index * kPointerSize); | |
160 } | |
161 | |
162 // Random-access store to a frame-top relative frame element. The result | |
163 // becomes owned by the frame and is invalidated. | |
164 void SetElementAt(int index, Result* value); | |
165 | |
166 // Set a frame element to a constant. The index is frame-top relative. | |
167 void SetElementAt(int index, Handle<Object> value) { | |
168 Result temp(value, cgen_); | |
169 SetElementAt(index, &temp); | |
170 } | |
171 | |
172 void PushElementAt(int index) { | |
173 PushFrameSlotAt(elements_.length() - index - 1); | |
174 } | |
175 | |
176 // A frame-allocated local as an assembly operand. | |
177 MemOperand LocalAt(int index) const { | |
178 ASSERT(0 <= index); | |
179 ASSERT(index < local_count_); | |
180 return MemOperand(fp, kLocal0Offset - index * kPointerSize); | |
181 } | |
182 | |
183 // Push a copy of the value of a local frame slot on top of the frame. | |
184 void PushLocalAt(int index) { | |
185 PushFrameSlotAt(local0_index() + index); | |
186 } | |
187 | |
188 // Push the value of a local frame slot on top of the frame and invalidate | |
189 // the local slot. The slot should be written to before trying to read | |
190 // from it again. | |
191 void TakeLocalAt(int index) { | |
192 TakeFrameSlotAt(local0_index() + index); | |
193 } | |
194 | |
195 // Store the top value on the virtual frame into a local frame slot. The | |
196 // value is left in place on top of the frame. | |
197 void StoreToLocalAt(int index) { | |
198 StoreToFrameSlotAt(local0_index() + index); | |
199 } | |
200 | |
201 // Push the address of the receiver slot on the frame. | |
202 void PushReceiverSlotAddress(); | |
203 | |
204 // The function frame slot. | |
205 MemOperand Function() const { return MemOperand(fp, kFunctionOffset); } | |
206 | |
207 // Push the function on top of the frame. | |
208 void PushFunction() { PushFrameSlotAt(function_index()); } | |
209 | |
210 // The context frame slot. | |
211 MemOperand Context() const { return MemOperand(fp, kContextOffset); } | |
212 | |
213 // Save the value of the esi register to the context frame slot. | |
214 void SaveContextRegister(); | |
215 | |
216 // Restore the esi register from the value of the context frame | |
217 // slot. | |
218 void RestoreContextRegister(); | |
219 | |
220 // A parameter as an assembly operand. | |
221 MemOperand ParameterAt(int index) const { | |
222 // Index -1 corresponds to the receiver. | |
223 ASSERT(-1 <= index && index <= parameter_count_); | |
224 return MemOperand(fp, (1 + parameter_count_ - index) * kPointerSize); | |
225 } | |
226 | |
227 // Push a copy of the value of a parameter frame slot on top of the frame. | |
228 void PushParameterAt(int index) { | |
229 PushFrameSlotAt(param0_index() + index); | |
230 } | |
231 | |
232 // Push the value of a paramter frame slot on top of the frame and | |
233 // invalidate the parameter slot. The slot should be written to before | |
234 // trying to read from it again. | |
235 void TakeParameterAt(int index) { | |
236 TakeFrameSlotAt(param0_index() + index); | |
237 } | |
238 | |
239 // Store the top value on the virtual frame into a parameter frame slot. | |
240 // The value is left in place on top of the frame. | |
241 void StoreToParameterAt(int index) { | |
242 StoreToFrameSlotAt(param0_index() + index); | |
243 } | |
244 | |
245 // The receiver frame slot. | |
246 MemOperand Receiver() const { return ParameterAt(-1); } | |
247 | |
248 // Push a try-catch or try-finally handler on top of the virtual frame. | |
249 void PushTryHandler(HandlerType type); | |
250 | |
251 // Call stub given the number of arguments it expects on (and | |
252 // removes from) the stack. | |
253 Result CallStub(CodeStub* stub, int arg_count); | |
254 | |
255 // Call stub that expects its argument in r0. The argument is given | |
256 // as a result which must be the register r0. | |
257 Result CallStub(CodeStub* stub, Result* arg); | |
258 | |
259 // Call stub that expects its arguments in r1 and r0. The arguments | |
260 // are given as results which must be the appropriate registers. | |
261 Result CallStub(CodeStub* stub, Result* arg0, Result* arg1); | |
262 | |
263 // Call runtime given the number of arguments expected on (and | |
264 // removed from) the stack. | |
265 Result CallRuntime(Runtime::Function* f, int arg_count); | |
266 Result CallRuntime(Runtime::FunctionId id, int arg_count); | |
267 | |
268 // Invoke builtin given the number of arguments it expects on (and | |
269 // removes from) the stack. | |
270 Result InvokeBuiltin(Builtins::JavaScript id, | |
271 InvokeJSFlags flag, | |
272 Result* arg_count_register, | |
273 int arg_count); | |
274 | |
275 // Call into an IC stub given the number of arguments it removes | |
276 // from the stack. Register arguments are passed as results and | |
277 // consumed by the call. | |
278 Result CallCodeObject(Handle<Code> ic, | |
279 RelocInfo::Mode rmode, | |
280 int dropped_args); | |
281 Result CallCodeObject(Handle<Code> ic, | |
282 RelocInfo::Mode rmode, | |
283 Result* arg, | |
284 int dropped_args); | |
285 Result CallCodeObject(Handle<Code> ic, | |
286 RelocInfo::Mode rmode, | |
287 Result* arg0, | |
288 Result* arg1, | |
289 int dropped_args); | |
290 | |
291 // Drop a number of elements from the top of the expression stack. May | |
292 // emit code to affect the physical frame. Does not clobber any registers | |
293 // excepting possibly the stack pointer. | |
294 void Drop(int count); | |
295 | |
296 // Drop one element. | |
297 void Drop() { Drop(1); } | |
298 | |
299 // Duplicate the top element of the frame. | |
300 void Dup() { PushFrameSlotAt(elements_.length() - 1); } | |
301 | |
302 // Pop an element from the top of the expression stack. Returns a | |
303 // Result, which may be a constant or a register. | |
304 Result Pop(); | |
305 | |
306 // Pop and save an element from the top of the expression stack and | |
307 // emit a corresponding pop instruction. | |
308 void EmitPop(Register reg); | |
309 | |
310 // Push an element on top of the expression stack and emit a | |
311 // corresponding push instruction. | |
312 void EmitPush(Register reg); | |
313 | |
314 // Push an element on the virtual frame. | |
315 void Push(Register reg, StaticType static_type = StaticType()); | |
316 void Push(Handle<Object> value); | |
317 void Push(Smi* value) { Push(Handle<Object>(value)); } | |
318 | |
319 // Pushing a result invalidates it (its contents become owned by the frame). | |
320 void Push(Result* result); | |
321 | |
322 // Nip removes zero or more elements from immediately below the top | |
323 // of the frame, leaving the previous top-of-frame value on top of | |
324 // the frame. Nip(k) is equivalent to x = Pop(), Drop(k), Push(x). | |
325 void Nip(int num_dropped); | |
326 | |
327 private: | |
328 static const int kLocal0Offset = JavaScriptFrameConstants::kLocal0Offset; | |
329 static const int kFunctionOffset = JavaScriptFrameConstants::kFunctionOffset; | |
330 static const int kContextOffset = StandardFrameConstants::kContextOffset; | |
331 | |
332 static const int kHandlerSize = StackHandlerConstants::kSize / kPointerSize; | |
333 static const int kPreallocatedElements = 5 + 8; // 8 expression stack slots. | |
334 | |
335 CodeGenerator* cgen_; | |
336 MacroAssembler* masm_; | |
337 | |
338 List<FrameElement> elements_; | |
339 | |
340 // The number of frame-allocated locals and parameters respectively. | |
341 int parameter_count_; | |
342 int local_count_; | |
343 | |
344 // The index of the element that is at the processor's stack pointer | |
345 // (the sp register). | |
346 int stack_pointer_; | |
347 | |
348 // The index of the element that is at the processor's frame pointer | |
349 // (the fp register). | |
350 int frame_pointer_; | |
351 | |
352 // The index of the register frame element using each register, or | |
353 // kIllegalIndex if a register is not on the frame. | |
354 int register_locations_[kNumRegisters]; | |
355 | |
356 // The index of the first parameter. The receiver lies below the first | |
357 // parameter. | |
358 int param0_index() const { return 1; } | |
359 | |
360 // The index of the context slot in the frame. | |
361 int context_index() const { | |
362 ASSERT(frame_pointer_ != kIllegalIndex); | |
363 return frame_pointer_ - 1; | |
364 } | |
365 | |
366 // The index of the function slot in the frame. It lies above the context | |
367 // slot. | |
368 int function_index() const { | |
369 ASSERT(frame_pointer_ != kIllegalIndex); | |
370 return frame_pointer_ - 2; | |
371 } | |
372 | |
373 // The index of the first local. Between the parameters and the locals | |
374 // lie the return address, the saved frame pointer, the context, and the | |
375 // function. | |
376 int local0_index() const { | |
377 ASSERT(frame_pointer_ != kIllegalIndex); | |
378 return frame_pointer_ + 2; | |
379 } | |
380 | |
381 // The index of the base of the expression stack. | |
382 int expression_base_index() const { return local0_index() + local_count_; } | |
383 | |
384 // Convert a frame index into a frame pointer relative offset into the | |
385 // actual stack. | |
386 int fp_relative(int index) const { | |
387 return (frame_pointer_ - index) * kPointerSize; | |
388 } | |
389 | |
390 // Record an occurrence of a register in the virtual frame. This has the | |
391 // effect of incrementing the register's external reference count and | |
392 // of updating the index of the register's location in the frame. | |
393 void Use(Register reg, int index); | |
394 | |
395 // Record that a register reference has been dropped from the frame. This | |
396 // decrements the register's external reference count and invalidates the | |
397 // index of the register's location in the frame. | |
398 void Unuse(Register reg); | |
399 | |
400 // Spill the element at a particular index---write it to memory if | |
401 // necessary, free any associated register, and forget its value if | |
402 // constant. | |
403 void SpillElementAt(int index); | |
404 | |
405 // Sync the element at a particular index. If it is a register or | |
406 // constant that disagrees with the value on the stack, write it to memory. | |
407 // Keep the element type as register or constant, and clear the dirty bit. | |
408 void SyncElementAt(int index); | |
409 | |
410 // Sync the range of elements in [begin, end). | |
411 void SyncRange(int begin, int end); | |
412 | |
413 // Sync a single unsynced element that lies beneath or at the stack pointer. | |
414 void SyncElementBelowStackPointer(int index); | |
415 | |
416 // Sync a single unsynced element that lies just above the stack pointer. | |
417 void SyncElementByPushing(int index); | |
418 | |
419 // Push a copy of a frame slot (typically a local or parameter) on top of | |
420 // the frame. | |
421 void PushFrameSlotAt(int index); | |
422 | |
423 // Push a the value of a frame slot (typically a local or parameter) on | |
424 // top of the frame and invalidate the slot. | |
425 void TakeFrameSlotAt(int index); | |
426 | |
427 // Store the value on top of the frame to a frame slot (typically a local | |
428 // or parameter). | |
429 void StoreToFrameSlotAt(int index); | |
430 | |
431 // Spill all elements in registers. Spill the top spilled_args elements | |
432 // on the frame. Sync all other frame elements. | |
433 // Then drop dropped_args elements from the virtual frame, to match | |
434 // the effect of an upcoming call that will drop them from the stack. | |
435 void PrepareForCall(int spilled_args, int dropped_args); | |
436 | |
437 // Move frame elements currently in registers or constants, that | |
438 // should be in memory in the expected frame, to memory. | |
439 void MergeMoveRegistersToMemory(VirtualFrame* expected); | |
440 | |
441 // Make the register-to-register moves necessary to | |
442 // merge this frame with the expected frame. | |
443 // Register to memory moves must already have been made, | |
444 // and memory to register moves must follow this call. | |
445 // This is because some new memory-to-register moves are | |
446 // created in order to break cycles of register moves. | |
447 // Used in the implementation of MergeTo(). | |
448 void MergeMoveRegistersToRegisters(VirtualFrame* expected); | |
449 | |
450 // Make the memory-to-register and constant-to-register moves | |
451 // needed to make this frame equal the expected frame. | |
452 // Called after all register-to-memory and register-to-register | |
453 // moves have been made. After this function returns, the frames | |
454 // should be equal. | |
455 void MergeMoveMemoryToRegisters(VirtualFrame* expected); | |
456 | |
457 // Invalidates a frame slot (puts an invalid frame element in it). | |
458 // Copies on the frame are correctly handled, and if this slot was | |
459 // the backing store of copies, the index of the new backing store | |
460 // is returned. Otherwise, returns kIllegalIndex. | |
461 // Register counts are correctly updated. | |
462 int InvalidateFrameSlotAt(int index); | |
463 | |
464 // Call a code stub that has already been prepared for calling (via | |
465 // PrepareForCall). | |
466 Result RawCallStub(CodeStub* stub); | |
467 | |
468 // Calls a code object which has already been prepared for calling | |
469 // (via PrepareForCall). | |
470 Result RawCallCodeObject(Handle<Code> code, RelocInfo::Mode rmode); | |
471 | |
472 bool Equals(VirtualFrame* other); | |
473 | |
474 friend class JumpTarget; | |
475 }; | |
476 | |
477 | |
478 } } // namespace v8::internal | |
479 | |
480 #endif // V8_VIRTUAL_FRAME_ARM_H_ | |
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