js/src/jit/BaselineIC.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef jit_BaselineIC_h
   8 #define jit_BaselineIC_h
   9
  10 #include "mozilla/Assertions.h"
  11 #include "mozilla/Attributes.h"
  12
  13 #include <stddef.h>
  14 #include <stdint.h>
  15
  16 #include "jit/ICState.h"
  17 #include "jit/JitCode.h"
  18 #include "jit/shared/Assembler-shared.h"
  19 #include "jit/TypeData.h"
  20 #include "js/TypeDecls.h"
  21
  22 class JS_PUBLIC_API JSTracer;
  23
  24 enum class JSOp : uint8_t;
  25
  26 namespace js {
  27
  28 MOZ_COLD void ReportOutOfMemory(JSContext* cx);
  29
  30 namespace jit {
  31
  32 class BaselineFrame;
  33 class CacheIRStubInfo;
  34 class ICScript;
  35
  36 enum class VMFunctionId;
  37
  38 // [SMDOC] JIT Inline Caches (ICs)
  39 //
  40 // Baseline Inline Caches are polymorphic caches that aggressively
  41 // share their stub code.
  42 //
  43 // Every polymorphic site contains a linked list of stubs which are
  44 // specific to that site.  These stubs are composed of a |StubData|
  45 // structure that stores parametrization information (e.g.
  46 // the shape pointer for a shape-check-and-property-get stub), any
  47 // dynamic information (e.g. warm-up counters), a pointer to the stub code,
  48 // and a pointer to the next stub state in the linked list.
  49 //
  50 // Every BaselineScript keeps an table of |CacheDescriptor| data
  51 // structures, which store the following:
  52 //      A pointer to the first StubData in the cache.
  53 //      The bytecode PC of the relevant IC.
  54 //      The machine-code PC where the call to the stubcode returns.
  55 //
  56 // A diagram:
  57 //
  58 //        Control flow                  Pointers
  59 //      =======#                     ----.     .---->
  60 //             #                         |     |
  61 //             #======>                  \-----/
  62 //
  63 //
  64 //                                   .---------------------------------------.
  65 //                                   |         .-------------------------.   |
  66 //                                   |         |         .----.          |   |
  67 //         Baseline                  |         |         |    |          |   |
  68 //         JIT Code              0   ^     1   ^     2   ^    |          |   |
  69 //     +--------------+    .-->+-----+   +-----+   +-----+    |          |   |
  70 //     |              |  #=|==>|     |==>|     |==>| FB  |    |          |   |
  71 //     |              |  # |   +-----+   +-----+   +-----+    |          |   |
  72 //     |              |  # |      #         #         #       |          |   |
  73 //     |==============|==# |      #         #         #       |          |   |
  74 //     |=== IC =======|    |      #         #         #       |          |   |
  75 //  .->|==============|<===|======#=========#=========#       |          |   |
  76 //  |  |              |    |                                  |          |   |
  77 //  |  |              |    |                                  |          |   |
  78 //  |  |              |    |                                  |          |   |
  79 //  |  |              |    |                                  v          |   |
  80 //  |  |              |    |                              +---------+    |   |
  81 //  |  |              |    |                              | Fallback|    |   |
  82 //  |  |              |    |                              | Stub    |    |   |
  83 //  |  |              |    |                              | Code    |    |   |
  84 //  |  |              |    |                              +---------+    |   |
  85 //  |  +--------------+    |                                             |   |
  86 //  |         |_______     |                              +---------+    |   |
  87 //  |                |     |                              | Stub    |<---/   |
  88 //  |        IC      |     \--.                           | Code    |        |
  89 //  |    Descriptor  |        |                           +---------+        |
  90 //  |      Table     v        |                                              |
  91 //  |  +-----------------+    |                           +---------+        |
  92 //  \--| Ins | PC | Stub |----/                           | Stub    |<-------/
  93 //     +-----------------+                                | Code    |
  94 //     |       ...       |                                +---------+
  95 //     +-----------------+
  96 //                                                          Shared
  97 //                                                          Stub Code
  98 //
  99
 100 class ICStub;
 101 class ICCacheIRStub;
 102 class ICFallbackStub;
 103
 104 #ifdef JS_JITSPEW
 105 void FallbackICSpew(JSContext* cx, ICFallbackStub* stub, const char* fmt, ...)
 106     MOZ_FORMAT_PRINTF(3, 4);
 107 #else
 108 #  define FallbackICSpew(...)
 109 #endif
 110
 111 // An entry in the ICScript IC table. There's one ICEntry per IC.
 112 class ICEntry {
 113   // A pointer to the first IC stub for this instruction.
 114   ICStub* firstStub_;
 115
 116  public:
 117   explicit ICEntry(ICStub* firstStub) : firstStub_(firstStub) {}
 118
 119   ICStub* firstStub() const {
 120     MOZ_ASSERT(firstStub_);
 121     return firstStub_;
 122   }
 123
 124   void setFirstStub(ICStub* stub) { firstStub_ = stub; }
 125
 126   static constexpr size_t offsetOfFirstStub() {
 127     return offsetof(ICEntry, firstStub_);
 128   }
 129
 130   void trace(JSTracer* trc);
 131   bool traceWeak(JSTracer* trc);
 132 };
 133
 134 //
 135 // Base class for all IC stubs.
 136 //
 137 class ICStub {
 138   friend class ICFallbackStub;
 139
 140  protected:
 141   // The raw jitcode to call for this stub.
 142   uint8_t* stubCode_;
 143
 144   // Counts the number of times the stub was entered
 145   //
 146   // See Bug 1494473 comment 6 for a mechanism to handle overflow if overflow
 147   // becomes a concern.
 148   uint32_t enteredCount_ = 0;
 149
 150   // Tracks input types for some CacheIR stubs, to help optimize
 151   // polymorphic cases. Stored in the base class to make use of
 152   // padding bytes.
 153   TypeData typeData_;
 154
 155   // Whether this is an ICFallbackStub or an ICCacheIRStub.
 156   bool isFallback_;
 157
 158   ICStub(uint8_t* stubCode, bool isFallback)
 159       : stubCode_(stubCode), isFallback_(isFallback) {
 160     MOZ_ASSERT(stubCode != nullptr);
 161   }
 162
 163  public:
 164   inline bool isFallback() const { return isFallback_; }
 165
 166   inline ICStub* maybeNext() const;
 167
 168   inline const ICFallbackStub* toFallbackStub() const {
 169     MOZ_ASSERT(isFallback());
 170     return reinterpret_cast<const ICFallbackStub*>(this);
 171   }
 172
 173   inline ICFallbackStub* toFallbackStub() {
 174     MOZ_ASSERT(isFallback());
 175     return reinterpret_cast<ICFallbackStub*>(this);
 176   }
 177
 178   ICCacheIRStub* toCacheIRStub() {
 179     MOZ_ASSERT(!isFallback());
 180     return reinterpret_cast<ICCacheIRStub*>(this);
 181   }
 182   const ICCacheIRStub* toCacheIRStub() const {
 183     MOZ_ASSERT(!isFallback());
 184     return reinterpret_cast<const ICCacheIRStub*>(this);
 185   }
 186
 187   bool usesTrampolineCode() const {
 188     // All fallback code is stored in a single JitCode instance, so we can't
 189     // call JitCode::FromExecutable on the raw pointer.
 190     return isFallback();
 191   }
 192   JitCode* jitCode() {
 193     MOZ_ASSERT(!usesTrampolineCode());
 194     return JitCode::FromExecutable(stubCode_);
 195   }
 196
 197   uint32_t enteredCount() const { return enteredCount_; }
 198   inline void incrementEnteredCount() { enteredCount_++; }
 199   void resetEnteredCount() { enteredCount_ = 0; }
 200
 201   static constexpr size_t offsetOfStubCode() {
 202     return offsetof(ICStub, stubCode_);
 203   }
 204   static constexpr size_t offsetOfEnteredCount() {
 205     return offsetof(ICStub, enteredCount_);
 206   }
 207 };
 208
 209 class ICFallbackStub final : public ICStub {
 210   friend class ICStubConstIterator;
 211
 212  protected:
 213   // The PC offset of this IC's bytecode op within the JSScript.
 214   uint32_t pcOffset_;
 215
 216   // The state of this IC.
 217   ICState state_{};
 218
 219  public:
 220   explicit ICFallbackStub(uint32_t pcOffset, TrampolinePtr stubCode)
 221       : ICStub(stubCode.value, /* isFallback = */ true), pcOffset_(pcOffset) {}
 222
 223   inline size_t numOptimizedStubs() const { return state_.numOptimizedStubs(); }
 224
 225   bool newStubIsFirstStub() const { return state_.newStubIsFirstStub(); }
 226
 227   ICState& state() { return state_; }
 228
 229   uint32_t pcOffset() const { return pcOffset_; }
 230
 231   // Add a new stub to the IC chain terminated by this fallback stub.
 232   inline void addNewStub(ICEntry* icEntry, ICCacheIRStub* stub);
 233
 234   void discardStubs(JSContext* cx, ICEntry* icEntry);
 235
 236   void clearUsedByTranspiler() { state_.clearUsedByTranspiler(); }
 237   void setUsedByTranspiler() { state_.setUsedByTranspiler(); }
 238   bool usedByTranspiler() const { return state_.usedByTranspiler(); }
 239
 240   void clearHasFoldedStub() { state_.clearHasFoldedStub(); }
 241   void setHasFoldedStub() { state_.setHasFoldedStub(); }
 242   bool hasFoldedStub() const { return state_.hasFoldedStub(); }
 243
 244   TrialInliningState trialInliningState() const {
 245     return state_.trialInliningState();
 246   }
 247   void setTrialInliningState(TrialInliningState state) {
 248     state_.setTrialInliningState(state);
 249   }
 250
 251   void trackNotAttached();
 252
 253   void unlinkStub(Zone* zone, ICEntry* icEntry, ICCacheIRStub* prev,
 254                   ICCacheIRStub* stub);
 255   void unlinkStubUnbarriered(ICEntry* icEntry, ICCacheIRStub* prev,
 256                              ICCacheIRStub* stub);
 257 };
 258
 259 class ICCacheIRStub final : public ICStub {
 260   // Pointer to next IC stub.
 261   ICStub* next_ = nullptr;
 262
 263   const CacheIRStubInfo* stubInfo_;
 264
 265 #ifndef JS_64BIT
 266   // Ensure stub data is 8-byte aligned on 32-bit.
 267   uintptr_t padding_ = 0;
 268 #endif
 269
 270  public:
 271   ICCacheIRStub(JitCode* stubCode, const CacheIRStubInfo* stubInfo)
 272       : ICStub(stubCode->raw(), /* isFallback = */ false),
 273         stubInfo_(stubInfo) {}
 274
 275   ICStub* next() const { return next_; }
 276   void setNext(ICStub* stub) { next_ = stub; }
 277
 278   ICCacheIRStub* nextCacheIR() const {
 279     return next_->isFallback() ? nullptr : next_->toCacheIRStub();
 280   }
 281
 282   const CacheIRStubInfo* stubInfo() const { return stubInfo_; }
 283   uint8_t* stubDataStart();
 284
 285   void trace(JSTracer* trc);
 286   bool traceWeak(JSTracer* trc);
 287
 288   // Optimized stubs get purged on GC.  But some stubs can be active on the
 289   // stack during GC - specifically the ones that can make calls.  To ensure
 290   // that these do not get purged, all stubs that can make calls are allocated
 291   // in the fallback stub space.
 292   bool makesGCCalls() const;
 293   bool allocatedInFallbackSpace() const { return makesGCCalls(); }
 294
 295   static constexpr size_t offsetOfNext() {
 296     return offsetof(ICCacheIRStub, next_);
 297   }
 298
 299   void setTypeData(TypeData data) { typeData_ = data; }
 300   TypeData typeData() const { return typeData_; }
 301 };
 302
 303 // Assert stub size is what we expect to catch regressions.
 304 #ifdef JS_64BIT
 305 static_assert(sizeof(ICFallbackStub) == 3 * sizeof(uintptr_t));
 306 static_assert(sizeof(ICCacheIRStub) == 4 * sizeof(uintptr_t));
 307 #else
 308 static_assert(sizeof(ICFallbackStub) == 5 * sizeof(uintptr_t));
 309 static_assert(sizeof(ICCacheIRStub) == 6 * sizeof(uintptr_t));
 310 #endif
 311
 312 inline ICStub* ICStub::maybeNext() const {
 313   return isFallback() ? nullptr : toCacheIRStub()->next();
 314 }
 315
 316 inline void ICFallbackStub::addNewStub(ICEntry* icEntry, ICCacheIRStub* stub) {
 317   MOZ_ASSERT(stub->next() == nullptr);
 318   stub->setNext(icEntry->firstStub());
 319   icEntry->setFirstStub(stub);
 320   state_.trackAttached();
 321 }
 322
 323 AllocatableGeneralRegisterSet BaselineICAvailableGeneralRegs(size_t numInputs);
 324
 325 bool ICSupportsPolymorphicTypeData(JSOp op);
 326
 327 struct IonOsrTempData;
 328
 329 extern bool DoCallFallback(JSContext* cx, BaselineFrame* frame,
 330                            ICFallbackStub* stub, uint32_t argc, Value* vp,
 331                            MutableHandleValue res);
 332
 333 extern bool DoSpreadCallFallback(JSContext* cx, BaselineFrame* frame,
 334                                  ICFallbackStub* stub, Value* vp,
 335                                  MutableHandleValue res);
 336
 337 extern bool DoToBoolFallback(JSContext* cx, BaselineFrame* frame,
 338                              ICFallbackStub* stub, HandleValue arg,
 339                              MutableHandleValue ret);
 340
 341 extern bool DoGetElemSuperFallback(JSContext* cx, BaselineFrame* frame,
 342                                    ICFallbackStub* stub, HandleValue lhs,
 343                                    HandleValue rhs, HandleValue receiver,
 344                                    MutableHandleValue res);
 345
 346 extern bool DoGetElemFallback(JSContext* cx, BaselineFrame* frame,
 347                               ICFallbackStub* stub, HandleValue lhs,
 348                               HandleValue rhs, MutableHandleValue res);
 349
 350 extern bool DoSetElemFallback(JSContext* cx, BaselineFrame* frame,
 351                               ICFallbackStub* stub, Value* stack,
 352                               HandleValue objv, HandleValue index,
 353                               HandleValue rhs);
 354
 355 extern bool DoInFallback(JSContext* cx, BaselineFrame* frame,
 356                          ICFallbackStub* stub, HandleValue key,
 357                          HandleValue objValue, MutableHandleValue res);
 358
 359 extern bool DoHasOwnFallback(JSContext* cx, BaselineFrame* frame,
 360                              ICFallbackStub* stub, HandleValue keyValue,
 361                              HandleValue objValue, MutableHandleValue res);
 362
 363 extern bool DoCheckPrivateFieldFallback(JSContext* cx, BaselineFrame* frame,
 364                                         ICFallbackStub* stub,
 365                                         HandleValue objValue,
 366                                         HandleValue keyValue,
 367                                         MutableHandleValue res);
 368
 369 extern bool DoGetNameFallback(JSContext* cx, BaselineFrame* frame,
 370                               ICFallbackStub* stub, HandleObject envChain,
 371                               MutableHandleValue res);
 372
 373 extern bool DoBindNameFallback(JSContext* cx, BaselineFrame* frame,
 374                                ICFallbackStub* stub, HandleObject envChain,
 375                                MutableHandleValue res);
 376
 377 extern bool DoGetIntrinsicFallback(JSContext* cx, BaselineFrame* frame,
 378                                    ICFallbackStub* stub,
 379                                    MutableHandleValue res);
 380
 381 extern bool DoGetPropFallback(JSContext* cx, BaselineFrame* frame,
 382                               ICFallbackStub* stub, MutableHandleValue val,
 383                               MutableHandleValue res);
 384
 385 extern bool DoGetPropSuperFallback(JSContext* cx, BaselineFrame* frame,
 386                                    ICFallbackStub* stub, HandleValue receiver,
 387                                    MutableHandleValue val,
 388                                    MutableHandleValue res);
 389
 390 extern bool DoSetPropFallback(JSContext* cx, BaselineFrame* frame,
 391                               ICFallbackStub* stub, Value* stack,
 392                               HandleValue lhs, HandleValue rhs);
 393
 394 extern bool DoGetIteratorFallback(JSContext* cx, BaselineFrame* frame,
 395                                   ICFallbackStub* stub, HandleValue value,
 396                                   MutableHandleValue res);
 397
 398 extern bool DoOptimizeSpreadCallFallback(JSContext* cx, BaselineFrame* frame,
 399                                          ICFallbackStub* stub,
 400                                          HandleValue value,
 401                                          MutableHandleValue res);
 402
 403 extern bool DoInstanceOfFallback(JSContext* cx, BaselineFrame* frame,
 404                                  ICFallbackStub* stub, HandleValue lhs,
 405                                  HandleValue rhs, MutableHandleValue res);
 406
 407 extern bool DoTypeOfFallback(JSContext* cx, BaselineFrame* frame,
 408                              ICFallbackStub* stub, HandleValue val,
 409                              MutableHandleValue res);
 410
 411 extern bool DoToPropertyKeyFallback(JSContext* cx, BaselineFrame* frame,
 412                                     ICFallbackStub* stub, HandleValue val,
 413                                     MutableHandleValue res);
 414
 415 extern bool DoRestFallback(JSContext* cx, BaselineFrame* frame,
 416                            ICFallbackStub* stub, MutableHandleValue res);
 417
 418 extern bool DoUnaryArithFallback(JSContext* cx, BaselineFrame* frame,
 419                                  ICFallbackStub* stub, HandleValue val,
 420                                  MutableHandleValue res);
 421
 422 extern bool DoBinaryArithFallback(JSContext* cx, BaselineFrame* frame,
 423                                   ICFallbackStub* stub, HandleValue lhs,
 424                                   HandleValue rhs, MutableHandleValue ret);
 425
 426 extern bool DoNewArrayFallback(JSContext* cx, BaselineFrame* frame,
 427                                ICFallbackStub* stub, MutableHandleValue res);
 428
 429 extern bool DoNewObjectFallback(JSContext* cx, BaselineFrame* frame,
 430                                 ICFallbackStub* stub, MutableHandleValue res);
 431
 432 extern bool DoCompareFallback(JSContext* cx, BaselineFrame* frame,
 433                               ICFallbackStub* stub, HandleValue lhs,
 434                               HandleValue rhs, MutableHandleValue ret);
 435
 436 extern bool DoCloseIterFallback(JSContext* cx, BaselineFrame* frame,
 437                                 ICFallbackStub* stub, HandleObject iter);
 438
 439 }  // namespace jit
 440 }  // namespace js
 441
 442 #endif /* jit_BaselineIC_h */