Source/JavaScriptCore/bytecode/CodeBlock.cpp

   1 /*
   2  * Copyright (C) 2008-2017 Apple Inc. All rights reserved.
   3  * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1.  Redistributions of source code must retain the above copyright
  10  *     notice, this list of conditions and the following disclaimer.
  11  * 2.  Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
  15  *     its contributors may be used to endorse or promote products derived
  16  *     from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  22  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include "config.h"
  31 #include "CodeBlock.h"
  32
  33 #include "ArithProfile.h"
  34 #include "BasicBlockLocation.h"
  35 #include "BytecodeDumper.h"
  36 #include "BytecodeGenerator.h"
  37 #include "BytecodeLivenessAnalysis.h"
  38 #include "BytecodeUseDef.h"
  39 #include "CallLinkStatus.h"
  40 #include "CodeBlockSet.h"
  41 #include "DFGCapabilities.h"
  42 #include "DFGCommon.h"
  43 #include "DFGDriver.h"
  44 #include "DFGJITCode.h"
  45 #include "DFGWorklist.h"
  46 #include "Debugger.h"
  47 #include "EvalCodeBlock.h"
  48 #include "FullCodeOrigin.h"
  49 #include "FunctionCodeBlock.h"
  50 #include "FunctionExecutableDump.h"
  51 #include "GetPutInfo.h"
  52 #include "InlineCallFrame.h"
  53 #include "InterpreterInlines.h"
  54 #include "JIT.h"
  55 #include "JITMathIC.h"
  56 #include "JSCInlines.h"
  57 #include "JSCJSValue.h"
  58 #include "JSFunction.h"
  59 #include "JSLexicalEnvironment.h"
  60 #include "JSModuleEnvironment.h"
  61 #include "JSSet.h"
  62 #include "JSString.h"
  63 #include "LLIntData.h"
  64 #include "LLIntEntrypoint.h"
  65 #include "LLIntPrototypeLoadAdaptiveStructureWatchpoint.h"
  66 #include "LowLevelInterpreter.h"
  67 #include "ModuleProgramCodeBlock.h"
  68 #include "PCToCodeOriginMap.h"
  69 #include "PolymorphicAccess.h"
  70 #include "ProfilerDatabase.h"
  71 #include "ProgramCodeBlock.h"
  72 #include "ReduceWhitespace.h"
  73 #include "Repatch.h"
  74 #include "SlotVisitorInlines.h"
  75 #include "StackVisitor.h"
  76 #include "StructureStubInfo.h"
  77 #include "TypeLocationCache.h"
  78 #include "TypeProfiler.h"
  79 #include "UnlinkedInstructionStream.h"
  80 #include "VMInlines.h"
  81 #include <wtf/BagToHashMap.h>
  82 #include <wtf/CommaPrinter.h>
  83 #include <wtf/SimpleStats.h>
  84 #include <wtf/StringExtras.h>
  85 #include <wtf/StringPrintStream.h>
  86 #include <wtf/text/UniquedStringImpl.h>
  87
  88 #if ENABLE(JIT)
  89 #include "RegisterAtOffsetList.h"
  90 #endif
  91
  92 #if ENABLE(DFG_JIT)
  93 #include "DFGOperations.h"
  94 #endif
  95
  96 #if ENABLE(FTL_JIT)
  97 #include "FTLJITCode.h"
  98 #endif
  99
 100 namespace JSC {
 101
 102 const ClassInfo CodeBlock::s_info = {
 103     "CodeBlock", 0, 0,
 104     CREATE_METHOD_TABLE(CodeBlock)
 105 };
 106
 107 CString CodeBlock::inferredName() const
 108 {
 109     switch (codeType()) {
 110     case GlobalCode:
 111         return "<global>";
 112     case EvalCode:
 113         return "<eval>";
 114     case FunctionCode:
 115         return jsCast<FunctionExecutable*>(ownerExecutable())->inferredName().utf8();
 116     case ModuleCode:
 117         return "<module>";
 118     default:
 119         CRASH();
 120         return CString("", 0);
 121     }
 122 }
 123
 124 bool CodeBlock::hasHash() const
 125 {
 126     return !!m_hash;
 127 }
 128
 129 bool CodeBlock::isSafeToComputeHash() const
 130 {
 131     return !isCompilationThread();
 132 }
 133
 134 CodeBlockHash CodeBlock::hash() const
 135 {
 136     if (!m_hash) {
 137         RELEASE_ASSERT(isSafeToComputeHash());
 138         m_hash = CodeBlockHash(ownerScriptExecutable()->source(), specializationKind());
 139     }
 140     return m_hash;
 141 }
 142
 143 CString CodeBlock::sourceCodeForTools() const
 144 {
 145     if (codeType() != FunctionCode)
 146         return ownerScriptExecutable()->source().toUTF8();
 147
 148     SourceProvider* provider = source();
 149     FunctionExecutable* executable = jsCast<FunctionExecutable*>(ownerExecutable());
 150     UnlinkedFunctionExecutable* unlinked = executable->unlinkedExecutable();
 151     unsigned unlinkedStartOffset = unlinked->startOffset();
 152     unsigned linkedStartOffset = executable->source().startOffset();
 153     int delta = linkedStartOffset - unlinkedStartOffset;
 154     unsigned rangeStart = delta + unlinked->unlinkedFunctionNameStart();
 155     unsigned rangeEnd = delta + unlinked->startOffset() + unlinked->sourceLength();
 156     return toCString(
 157         "function ",
 158         provider->source().substring(rangeStart, rangeEnd - rangeStart).utf8());
 159 }
 160
 161 CString CodeBlock::sourceCodeOnOneLine() const
 162 {
 163     return reduceWhitespace(sourceCodeForTools());
 164 }
 165
 166 CString CodeBlock::hashAsStringIfPossible() const
 167 {
 168     if (hasHash() || isSafeToComputeHash())
 169         return toCString(hash());
 170     return "<no-hash>";
 171 }
 172
 173 void CodeBlock::dumpAssumingJITType(PrintStream& out, JITCode::JITType jitType) const
 174 {
 175     out.print(inferredName(), "#", hashAsStringIfPossible());
 176     out.print(":[", RawPointer(this), "->");
 177     if (!!m_alternative)
 178         out.print(RawPointer(alternative()), "->");
 179     out.print(RawPointer(ownerExecutable()), ", ", jitType, codeType());
 180
 181     if (codeType() == FunctionCode)
 182         out.print(specializationKind());
 183     out.print(", ", instructionCount());
 184     if (this->jitType() == JITCode::BaselineJIT && m_shouldAlwaysBeInlined)
 185         out.print(" (ShouldAlwaysBeInlined)");
 186     if (ownerScriptExecutable()->neverInline())
 187         out.print(" (NeverInline)");
 188     if (ownerScriptExecutable()->neverOptimize())
 189         out.print(" (NeverOptimize)");
 190     else if (ownerScriptExecutable()->neverFTLOptimize())
 191         out.print(" (NeverFTLOptimize)");
 192     if (ownerScriptExecutable()->didTryToEnterInLoop())
 193         out.print(" (DidTryToEnterInLoop)");
 194     if (ownerScriptExecutable()->isStrictMode())
 195         out.print(" (StrictMode)");
 196     if (m_didFailJITCompilation)
 197         out.print(" (JITFail)");
 198     if (this->jitType() == JITCode::BaselineJIT && m_didFailFTLCompilation)
 199         out.print(" (FTLFail)");
 200     if (this->jitType() == JITCode::BaselineJIT && m_hasBeenCompiledWithFTL)
 201         out.print(" (HadFTLReplacement)");
 202     out.print("]");
 203 }
 204
 205 void CodeBlock::dump(PrintStream& out) const
 206 {
 207     dumpAssumingJITType(out, jitType());
 208 }
 209
 210 void CodeBlock::dumpSource()
 211 {
 212     dumpSource(WTF::dataFile());
 213 }
 214
 215 void CodeBlock::dumpSource(PrintStream& out)
 216 {
 217     ScriptExecutable* executable = ownerScriptExecutable();
 218     if (executable->isFunctionExecutable()) {
 219         FunctionExecutable* functionExecutable = reinterpret_cast<FunctionExecutable*>(executable);
 220         StringView source = functionExecutable->source().provider()->getRange(
 221             functionExecutable->parametersStartOffset(),
 222             functionExecutable->typeProfilingEndOffset() + 1); // Type profiling end offset is the character before the '}'.
 223
 224         out.print("function ", inferredName(), source);
 225         return;
 226     }
 227     out.print(executable->source().view());
 228 }
 229
 230 void CodeBlock::dumpBytecode()
 231 {
 232     dumpBytecode(WTF::dataFile());
 233 }
 234
 235 void CodeBlock::dumpBytecode(PrintStream& out)
 236 {
 237     StubInfoMap stubInfos;
 238     CallLinkInfoMap callLinkInfos;
 239     getStubInfoMap(stubInfos);
 240     getCallLinkInfoMap(callLinkInfos);
 241     BytecodeDumper<CodeBlock>::dumpBlock(this, instructions(), out, stubInfos, callLinkInfos);
 242 }
 243
 244 void CodeBlock::dumpBytecode(PrintStream& out, const Instruction* begin, const Instruction*& it, const StubInfoMap& stubInfos, const CallLinkInfoMap& callLinkInfos)
 245 {
 246     BytecodeDumper<CodeBlock>::dumpBytecode(this, out, begin, it, stubInfos, callLinkInfos);
 247 }
 248
 249 void CodeBlock::dumpBytecode(
 250     PrintStream& out, unsigned bytecodeOffset,
 251     const StubInfoMap& stubInfos, const CallLinkInfoMap& callLinkInfos)
 252 {
 253     const Instruction* it = instructions().begin() + bytecodeOffset;
 254     dumpBytecode(out, instructions().begin(), it, stubInfos, callLinkInfos);
 255 }
 256
 257 #define FOR_EACH_MEMBER_VECTOR(macro) \
 258     macro(instructions) \
 259     macro(callLinkInfos) \
 260     macro(linkedCallerList) \
 261     macro(identifiers) \
 262     macro(functionExpressions) \
 263     macro(constantRegisters)
 264
 265 template<typename T>
 266 static size_t sizeInBytes(const Vector<T>& vector)
 267 {
 268     return vector.capacity() * sizeof(T);
 269 }
 270
 271 namespace {
 272
 273 class PutToScopeFireDetail : public FireDetail {
 274 public:
 275     PutToScopeFireDetail(CodeBlock* codeBlock, const Identifier& ident)
 276         : m_codeBlock(codeBlock)
 277         , m_ident(ident)
 278     {
 279     }
 280
 281     void dump(PrintStream& out) const override
 282     {
 283         out.print("Linking put_to_scope in ", FunctionExecutableDump(jsCast<FunctionExecutable*>(m_codeBlock->ownerExecutable())), " for ", m_ident);
 284     }
 285
 286 private:
 287     CodeBlock* m_codeBlock;
 288     const Identifier& m_ident;
 289 };
 290
 291 } // anonymous namespace
 292
 293 CodeBlock::CodeBlock(VM* vm, Structure* structure, CopyParsedBlockTag, CodeBlock& other)
 294     : JSCell(*vm, structure)
 295     , m_globalObject(other.m_globalObject)
 296     , m_numCalleeLocals(other.m_numCalleeLocals)
 297     , m_numVars(other.m_numVars)
 298     , m_shouldAlwaysBeInlined(true)
 299 #if ENABLE(JIT)
 300     , m_capabilityLevelState(DFG::CapabilityLevelNotSet)
 301 #endif
 302     , m_didFailJITCompilation(false)
 303     , m_didFailFTLCompilation(false)
 304     , m_hasBeenCompiledWithFTL(false)
 305     , m_isConstructor(other.m_isConstructor)
 306     , m_isStrictMode(other.m_isStrictMode)
 307     , m_codeType(other.m_codeType)
 308     , m_unlinkedCode(*other.m_vm, this, other.m_unlinkedCode.get())
 309     , m_numberOfArgumentsToSkip(other.m_numberOfArgumentsToSkip)
 310     , m_hasDebuggerStatement(false)
 311     , m_steppingMode(SteppingModeDisabled)
 312     , m_numBreakpoints(0)
 313     , m_ownerExecutable(*other.m_vm, this, other.m_ownerExecutable.get())
 314     , m_vm(other.m_vm)
 315     , m_instructions(other.m_instructions)
 316     , m_thisRegister(other.m_thisRegister)
 317     , m_scopeRegister(other.m_scopeRegister)
 318     , m_hash(other.m_hash)
 319     , m_source(other.m_source)
 320     , m_sourceOffset(other.m_sourceOffset)
 321     , m_firstLineColumnOffset(other.m_firstLineColumnOffset)
 322     , m_constantRegisters(other.m_constantRegisters)
 323     , m_constantsSourceCodeRepresentation(other.m_constantsSourceCodeRepresentation)
 324     , m_functionDecls(other.m_functionDecls)
 325     , m_functionExprs(other.m_functionExprs)
 326     , m_osrExitCounter(0)
 327     , m_optimizationDelayCounter(0)
 328     , m_reoptimizationRetryCounter(0)
 329     , m_creationTime(std::chrono::steady_clock::now())
 330 {
 331     m_visitWeaklyHasBeenCalled = false;
 332
 333     ASSERT(heap()->isDeferred());
 334     ASSERT(m_scopeRegister.isLocal());
 335
 336     setNumParameters(other.numParameters());
 337 }
 338
 339 void CodeBlock::finishCreation(VM& vm, CopyParsedBlockTag, CodeBlock& other)
 340 {
 341     Base::finishCreation(vm);
 342
 343     optimizeAfterWarmUp();
 344     jitAfterWarmUp();
 345
 346     if (other.m_rareData) {
 347         createRareDataIfNecessary();
 348
 349         m_rareData->m_exceptionHandlers = other.m_rareData->m_exceptionHandlers;
 350         m_rareData->m_constantBuffers = other.m_rareData->m_constantBuffers;
 351         m_rareData->m_switchJumpTables = other.m_rareData->m_switchJumpTables;
 352         m_rareData->m_stringSwitchJumpTables = other.m_rareData->m_stringSwitchJumpTables;
 353     }
 354
 355     heap()->m_codeBlocks->add(this);
 356 }
 357
 358 CodeBlock::CodeBlock(VM* vm, Structure* structure, ScriptExecutable* ownerExecutable, UnlinkedCodeBlock* unlinkedCodeBlock,
 359     JSScope* scope, RefPtr<SourceProvider>&& sourceProvider, unsigned sourceOffset, unsigned firstLineColumnOffset)
 360     : JSCell(*vm, structure)
 361     , m_globalObject(scope->globalObject()->vm(), this, scope->globalObject())
 362     , m_numCalleeLocals(unlinkedCodeBlock->m_numCalleeLocals)
 363     , m_numVars(unlinkedCodeBlock->m_numVars)
 364     , m_shouldAlwaysBeInlined(true)
 365 #if ENABLE(JIT)
 366     , m_capabilityLevelState(DFG::CapabilityLevelNotSet)
 367 #endif
 368     , m_didFailJITCompilation(false)
 369     , m_didFailFTLCompilation(false)
 370     , m_hasBeenCompiledWithFTL(false)
 371     , m_isConstructor(unlinkedCodeBlock->isConstructor())
 372     , m_isStrictMode(unlinkedCodeBlock->isStrictMode())
 373     , m_codeType(unlinkedCodeBlock->codeType())
 374     , m_unlinkedCode(m_globalObject->vm(), this, unlinkedCodeBlock)
 375     , m_hasDebuggerStatement(false)
 376     , m_steppingMode(SteppingModeDisabled)
 377     , m_numBreakpoints(0)
 378     , m_ownerExecutable(m_globalObject->vm(), this, ownerExecutable)
 379     , m_vm(unlinkedCodeBlock->vm())
 380     , m_thisRegister(unlinkedCodeBlock->thisRegister())
 381     , m_scopeRegister(unlinkedCodeBlock->scopeRegister())
 382     , m_source(WTFMove(sourceProvider))
 383     , m_sourceOffset(sourceOffset)
 384     , m_firstLineColumnOffset(firstLineColumnOffset)
 385     , m_osrExitCounter(0)
 386     , m_optimizationDelayCounter(0)
 387     , m_reoptimizationRetryCounter(0)
 388     , m_creationTime(std::chrono::steady_clock::now())
 389 {
 390     m_visitWeaklyHasBeenCalled = false;
 391
 392     ASSERT(heap()->isDeferred());
 393     ASSERT(m_scopeRegister.isLocal());
 394
 395     ASSERT(m_source);
 396     setNumParameters(unlinkedCodeBlock->numParameters());
 397 }
 398
 399 bool CodeBlock::finishCreation(VM& vm, ScriptExecutable* ownerExecutable, UnlinkedCodeBlock* unlinkedCodeBlock,
 400     JSScope* scope)
 401 {
 402     Base::finishCreation(vm);
 403
 404     if (vm.typeProfiler() || vm.controlFlowProfiler())
 405         vm.functionHasExecutedCache()->removeUnexecutedRange(ownerExecutable->sourceID(), ownerExecutable->typeProfilingStartOffset(), ownerExecutable->typeProfilingEndOffset());
 406
 407     setConstantRegisters(unlinkedCodeBlock->constantRegisters(), unlinkedCodeBlock->constantsSourceCodeRepresentation());
 408     if (!setConstantIdentifierSetRegisters(vm, unlinkedCodeBlock->constantIdentifierSets()))
 409         return false;
 410     if (unlinkedCodeBlock->usesGlobalObject())
 411         m_constantRegisters[unlinkedCodeBlock->globalObjectRegister().toConstantIndex()].set(*m_vm, this, m_globalObject.get());
 412
 413     for (unsigned i = 0; i < LinkTimeConstantCount; i++) {
 414         LinkTimeConstant type = static_cast<LinkTimeConstant>(i);
 415         if (unsigned registerIndex = unlinkedCodeBlock->registerIndexForLinkTimeConstant(type))
 416             m_constantRegisters[registerIndex].set(*m_vm, this, m_globalObject->jsCellForLinkTimeConstant(type));
 417     }
 418
 419     // We already have the cloned symbol table for the module environment since we need to instantiate
 420     // the module environments before linking the code block. We replace the stored symbol table with the already cloned one.
 421     if (UnlinkedModuleProgramCodeBlock* unlinkedModuleProgramCodeBlock = jsDynamicCast<UnlinkedModuleProgramCodeBlock*>(vm, unlinkedCodeBlock)) {
 422         SymbolTable* clonedSymbolTable = jsCast<ModuleProgramExecutable*>(ownerExecutable)->moduleEnvironmentSymbolTable();
 423         if (m_vm->typeProfiler()) {
 424             ConcurrentJSLocker locker(clonedSymbolTable->m_lock);
 425             clonedSymbolTable->prepareForTypeProfiling(locker);
 426         }
 427         replaceConstant(unlinkedModuleProgramCodeBlock->moduleEnvironmentSymbolTableConstantRegisterOffset(), clonedSymbolTable);
 428     }
 429
 430     bool shouldUpdateFunctionHasExecutedCache = vm.typeProfiler() || vm.controlFlowProfiler();
 431     m_functionDecls = RefCountedArray<WriteBarrier<FunctionExecutable>>(unlinkedCodeBlock->numberOfFunctionDecls());
 432     for (size_t count = unlinkedCodeBlock->numberOfFunctionDecls(), i = 0; i < count; ++i) {
 433         UnlinkedFunctionExecutable* unlinkedExecutable = unlinkedCodeBlock->functionDecl(i);
 434         if (shouldUpdateFunctionHasExecutedCache)
 435             vm.functionHasExecutedCache()->insertUnexecutedRange(ownerExecutable->sourceID(), unlinkedExecutable->typeProfilingStartOffset(), unlinkedExecutable->typeProfilingEndOffset());
 436         m_functionDecls[i].set(*m_vm, this, unlinkedExecutable->link(*m_vm, ownerExecutable->source()));
 437     }
 438
 439     m_functionExprs = RefCountedArray<WriteBarrier<FunctionExecutable>>(unlinkedCodeBlock->numberOfFunctionExprs());
 440     for (size_t count = unlinkedCodeBlock->numberOfFunctionExprs(), i = 0; i < count; ++i) {
 441         UnlinkedFunctionExecutable* unlinkedExecutable = unlinkedCodeBlock->functionExpr(i);
 442         if (shouldUpdateFunctionHasExecutedCache)
 443             vm.functionHasExecutedCache()->insertUnexecutedRange(ownerExecutable->sourceID(), unlinkedExecutable->typeProfilingStartOffset(), unlinkedExecutable->typeProfilingEndOffset());
 444         m_functionExprs[i].set(*m_vm, this, unlinkedExecutable->link(*m_vm, ownerExecutable->source()));
 445     }
 446
 447     if (unlinkedCodeBlock->hasRareData()) {
 448         createRareDataIfNecessary();
 449         if (size_t count = unlinkedCodeBlock->constantBufferCount()) {
 450             m_rareData->m_constantBuffers.grow(count);
 451             for (size_t i = 0; i < count; i++) {
 452                 const UnlinkedCodeBlock::ConstantBuffer& buffer = unlinkedCodeBlock->constantBuffer(i);
 453                 m_rareData->m_constantBuffers[i] = buffer;
 454             }
 455         }
 456         if (size_t count = unlinkedCodeBlock->numberOfExceptionHandlers()) {
 457             m_rareData->m_exceptionHandlers.resizeToFit(count);
 458             for (size_t i = 0; i < count; i++) {
 459                 const UnlinkedHandlerInfo& unlinkedHandler = unlinkedCodeBlock->exceptionHandler(i);
 460                 HandlerInfo& handler = m_rareData->m_exceptionHandlers[i];
 461 #if ENABLE(JIT)
 462                 handler.initialize(unlinkedHandler, CodeLocationLabel(MacroAssemblerCodePtr::createFromExecutableAddress(LLInt::getCodePtr(op_catch))));
 463 #else
 464                 handler.initialize(unlinkedHandler);
 465 #endif
 466             }
 467         }
 468
 469         if (size_t count = unlinkedCodeBlock->numberOfStringSwitchJumpTables()) {
 470             m_rareData->m_stringSwitchJumpTables.grow(count);
 471             for (size_t i = 0; i < count; i++) {
 472                 UnlinkedStringJumpTable::StringOffsetTable::iterator ptr = unlinkedCodeBlock->stringSwitchJumpTable(i).offsetTable.begin();
 473                 UnlinkedStringJumpTable::StringOffsetTable::iterator end = unlinkedCodeBlock->stringSwitchJumpTable(i).offsetTable.end();
 474                 for (; ptr != end; ++ptr) {
 475                     OffsetLocation offset;
 476                     offset.branchOffset = ptr->value.branchOffset;
 477                     m_rareData->m_stringSwitchJumpTables[i].offsetTable.add(ptr->key, offset);
 478                 }
 479             }
 480         }
 481
 482         if (size_t count = unlinkedCodeBlock->numberOfSwitchJumpTables()) {
 483             m_rareData->m_switchJumpTables.grow(count);
 484             for (size_t i = 0; i < count; i++) {
 485                 UnlinkedSimpleJumpTable& sourceTable = unlinkedCodeBlock->switchJumpTable(i);
 486                 SimpleJumpTable& destTable = m_rareData->m_switchJumpTables[i];
 487                 destTable.branchOffsets = sourceTable.branchOffsets;
 488                 destTable.min = sourceTable.min;
 489             }
 490         }
 491     }
 492
 493     // Allocate metadata buffers for the bytecode
 494     if (size_t size = unlinkedCodeBlock->numberOfLLintCallLinkInfos())
 495         m_llintCallLinkInfos = RefCountedArray<LLIntCallLinkInfo>(size);
 496     if (size_t size = unlinkedCodeBlock->numberOfArrayProfiles())
 497         m_arrayProfiles.grow(size);
 498     if (size_t size = unlinkedCodeBlock->numberOfArrayAllocationProfiles())
 499         m_arrayAllocationProfiles = RefCountedArray<ArrayAllocationProfile>(size);
 500     if (size_t size = unlinkedCodeBlock->numberOfValueProfiles())
 501         m_valueProfiles = RefCountedArray<ValueProfile>(size);
 502     if (size_t size = unlinkedCodeBlock->numberOfObjectAllocationProfiles())
 503         m_objectAllocationProfiles = RefCountedArray<ObjectAllocationProfile>(size);
 504
 505 #if ENABLE(JIT)
 506     setCalleeSaveRegisters(RegisterSet::llintBaselineCalleeSaveRegisters());
 507 #endif
 508
 509     // Copy and translate the UnlinkedInstructions
 510     unsigned instructionCount = unlinkedCodeBlock->instructions().count();
 511     UnlinkedInstructionStream::Reader instructionReader(unlinkedCodeBlock->instructions());
 512
 513     // Bookkeep the strongly referenced module environments.
 514     HashSet<JSModuleEnvironment*> stronglyReferencedModuleEnvironments;
 515
 516     RefCountedArray<Instruction> instructions(instructionCount);
 517
 518     unsigned valueProfileCount = 0;
 519     auto linkValueProfile = [&](unsigned bytecodeOffset, unsigned opLength) {
 520         unsigned valueProfileIndex = valueProfileCount++;
 521         ValueProfile* profile = &m_valueProfiles[valueProfileIndex];
 522         ASSERT(profile->m_bytecodeOffset == -1);
 523         profile->m_bytecodeOffset = bytecodeOffset;
 524         instructions[bytecodeOffset + opLength - 1] = profile;
 525     };
 526
 527     for (unsigned i = 0; !instructionReader.atEnd(); ) {
 528         const UnlinkedInstruction* pc = instructionReader.next();
 529
 530         unsigned opLength = opcodeLength(pc[0].u.opcode);
 531
 532         instructions[i] = vm.interpreter->getOpcode(pc[0].u.opcode);
 533         for (size_t j = 1; j < opLength; ++j) {
 534             if (sizeof(int32_t) != sizeof(intptr_t))
 535                 instructions[i + j].u.pointer = 0;
 536             instructions[i + j].u.operand = pc[j].u.operand;
 537         }
 538         switch (pc[0].u.opcode) {
 539         case op_has_indexed_property: {
 540             int arrayProfileIndex = pc[opLength - 1].u.operand;
 541             m_arrayProfiles[arrayProfileIndex] = ArrayProfile(i);
 542
 543             instructions[i + opLength - 1] = &m_arrayProfiles[arrayProfileIndex];
 544             break;
 545         }
 546         case op_call_varargs:
 547         case op_tail_call_varargs:
 548         case op_tail_call_forward_arguments:
 549         case op_construct_varargs:
 550         case op_get_by_val: {
 551             int arrayProfileIndex = pc[opLength - 2].u.operand;
 552             m_arrayProfiles[arrayProfileIndex] = ArrayProfile(i);
 553
 554             instructions[i + opLength - 2] = &m_arrayProfiles[arrayProfileIndex];
 555             FALLTHROUGH;
 556         }
 557         case op_get_direct_pname:
 558         case op_get_by_id:
 559         case op_get_by_id_with_this:
 560         case op_try_get_by_id:
 561         case op_get_by_val_with_this:
 562         case op_get_from_arguments:
 563         case op_to_number:
 564         case op_get_argument: {
 565             linkValueProfile(i, opLength);
 566             break;
 567         }
 568
 569         case op_in:
 570         case op_put_by_val:
 571         case op_put_by_val_direct: {
 572             int arrayProfileIndex = pc[opLength - 1].u.operand;
 573             m_arrayProfiles[arrayProfileIndex] = ArrayProfile(i);
 574             instructions[i + opLength - 1] = &m_arrayProfiles[arrayProfileIndex];
 575             break;
 576         }
 577
 578         case op_new_array:
 579         case op_new_array_buffer:
 580         case op_new_array_with_size: {
 581             int arrayAllocationProfileIndex = pc[opLength - 1].u.operand;
 582             instructions[i + opLength - 1] = &m_arrayAllocationProfiles[arrayAllocationProfileIndex];
 583             break;
 584         }
 585         case op_new_object: {
 586             int objectAllocationProfileIndex = pc[opLength - 1].u.operand;
 587             ObjectAllocationProfile* objectAllocationProfile = &m_objectAllocationProfiles[objectAllocationProfileIndex];
 588             int inferredInlineCapacity = pc[opLength - 2].u.operand;
 589
 590             instructions[i + opLength - 1] = objectAllocationProfile;
 591             objectAllocationProfile->initialize(vm,
 592                 m_globalObject.get(), this, m_globalObject->objectPrototype(), inferredInlineCapacity);
 593             break;
 594         }
 595
 596         case op_call:
 597         case op_tail_call:
 598         case op_call_eval: {
 599             linkValueProfile(i, opLength);
 600             int arrayProfileIndex = pc[opLength - 2].u.operand;
 601             m_arrayProfiles[arrayProfileIndex] = ArrayProfile(i);
 602             instructions[i + opLength - 2] = &m_arrayProfiles[arrayProfileIndex];
 603             instructions[i + 5] = &m_llintCallLinkInfos[pc[5].u.operand];
 604             break;
 605         }
 606         case op_construct: {
 607             instructions[i + 5] = &m_llintCallLinkInfos[pc[5].u.operand];
 608             linkValueProfile(i, opLength);
 609             break;
 610         }
 611         case op_get_array_length:
 612             CRASH();
 613
 614         case op_resolve_scope: {
 615             const Identifier& ident = identifier(pc[3].u.operand);
 616             ResolveType type = static_cast<ResolveType>(pc[4].u.operand);
 617             RELEASE_ASSERT(type != LocalClosureVar);
 618             int localScopeDepth = pc[5].u.operand;
 619
 620             ResolveOp op = JSScope::abstractResolve(m_globalObject->globalExec(), localScopeDepth, scope, ident, Get, type, InitializationMode::NotInitialization);
 621             instructions[i + 4].u.operand = op.type;
 622             instructions[i + 5].u.operand = op.depth;
 623             if (op.lexicalEnvironment) {
 624                 if (op.type == ModuleVar) {
 625                     // Keep the linked module environment strongly referenced.
 626                     if (stronglyReferencedModuleEnvironments.add(jsCast<JSModuleEnvironment*>(op.lexicalEnvironment)).isNewEntry)
 627                         addConstant(op.lexicalEnvironment);
 628                     instructions[i + 6].u.jsCell.set(vm, this, op.lexicalEnvironment);
 629                 } else
 630                     instructions[i + 6].u.symbolTable.set(vm, this, op.lexicalEnvironment->symbolTable());
 631             } else if (JSScope* constantScope = JSScope::constantScopeForCodeBlock(op.type, this))
 632                 instructions[i + 6].u.jsCell.set(vm, this, constantScope);
 633             else
 634                 instructions[i + 6].u.pointer = nullptr;
 635             break;
 636         }
 637
 638         case op_get_from_scope: {
 639             linkValueProfile(i, opLength);
 640
 641             // get_from_scope dst, scope, id, GetPutInfo, Structure, Operand
 642
 643             int localScopeDepth = pc[5].u.operand;
 644             instructions[i + 5].u.pointer = nullptr;
 645
 646             GetPutInfo getPutInfo = GetPutInfo(pc[4].u.operand);
 647             ASSERT(!isInitialization(getPutInfo.initializationMode()));
 648             if (getPutInfo.resolveType() == LocalClosureVar) {
 649                 instructions[i + 4] = GetPutInfo(getPutInfo.resolveMode(), ClosureVar, getPutInfo.initializationMode()).operand();
 650                 break;
 651             }
 652
 653             const Identifier& ident = identifier(pc[3].u.operand);
 654             ResolveOp op = JSScope::abstractResolve(m_globalObject->globalExec(), localScopeDepth, scope, ident, Get, getPutInfo.resolveType(), InitializationMode::NotInitialization);
 655
 656             instructions[i + 4].u.operand = GetPutInfo(getPutInfo.resolveMode(), op.type, getPutInfo.initializationMode()).operand();
 657             if (op.type == ModuleVar)
 658                 instructions[i + 4].u.operand = GetPutInfo(getPutInfo.resolveMode(), ClosureVar, getPutInfo.initializationMode()).operand();
 659             if (op.type == GlobalVar || op.type == GlobalVarWithVarInjectionChecks || op.type == GlobalLexicalVar || op.type == GlobalLexicalVarWithVarInjectionChecks)
 660                 instructions[i + 5].u.watchpointSet = op.watchpointSet;
 661             else if (op.structure)
 662                 instructions[i + 5].u.structure.set(vm, this, op.structure);
 663             instructions[i + 6].u.pointer = reinterpret_cast<void*>(op.operand);
 664             break;
 665         }
 666
 667         case op_put_to_scope: {
 668             // put_to_scope scope, id, value, GetPutInfo, Structure, Operand
 669             GetPutInfo getPutInfo = GetPutInfo(pc[4].u.operand);
 670             if (getPutInfo.resolveType() == LocalClosureVar) {
 671                 // Only do watching if the property we're putting to is not anonymous.
 672                 if (static_cast<unsigned>(pc[2].u.operand) != UINT_MAX) {
 673                     int symbolTableIndex = pc[5].u.operand;
 674                     SymbolTable* symbolTable = jsCast<SymbolTable*>(getConstant(symbolTableIndex));
 675                     const Identifier& ident = identifier(pc[2].u.operand);
 676                     ConcurrentJSLocker locker(symbolTable->m_lock);
 677                     auto iter = symbolTable->find(locker, ident.impl());
 678                     ASSERT(iter != symbolTable->end(locker));
 679                     iter->value.prepareToWatch();
 680                     instructions[i + 5].u.watchpointSet = iter->value.watchpointSet();
 681                 } else
 682                     instructions[i + 5].u.watchpointSet = nullptr;
 683                 break;
 684             }
 685
 686             const Identifier& ident = identifier(pc[2].u.operand);
 687             int localScopeDepth = pc[5].u.operand;
 688             instructions[i + 5].u.pointer = nullptr;
 689             ResolveOp op = JSScope::abstractResolve(m_globalObject->globalExec(), localScopeDepth, scope, ident, Put, getPutInfo.resolveType(), getPutInfo.initializationMode());
 690
 691             instructions[i + 4].u.operand = GetPutInfo(getPutInfo.resolveMode(), op.type, getPutInfo.initializationMode()).operand();
 692             if (op.type == GlobalVar || op.type == GlobalVarWithVarInjectionChecks || op.type == GlobalLexicalVar || op.type == GlobalLexicalVarWithVarInjectionChecks)
 693                 instructions[i + 5].u.watchpointSet = op.watchpointSet;
 694             else if (op.type == ClosureVar || op.type == ClosureVarWithVarInjectionChecks) {
 695                 if (op.watchpointSet)
 696                     op.watchpointSet->invalidate(vm, PutToScopeFireDetail(this, ident));
 697             } else if (op.structure)
 698                 instructions[i + 5].u.structure.set(vm, this, op.structure);
 699             instructions[i + 6].u.pointer = reinterpret_cast<void*>(op.operand);
 700
 701             break;
 702         }
 703
 704         case op_profile_type: {
 705             RELEASE_ASSERT(vm.typeProfiler());
 706             // The format of this instruction is: op_profile_type regToProfile, TypeLocation*, flag, identifier?, resolveType?
 707             size_t instructionOffset = i + opLength - 1;
 708             unsigned divotStart, divotEnd;
 709             GlobalVariableID globalVariableID = 0;
 710             RefPtr<TypeSet> globalTypeSet;
 711             bool shouldAnalyze = m_unlinkedCode->typeProfilerExpressionInfoForBytecodeOffset(instructionOffset, divotStart, divotEnd);
 712             VirtualRegister profileRegister(pc[1].u.operand);
 713             ProfileTypeBytecodeFlag flag = static_cast<ProfileTypeBytecodeFlag>(pc[3].u.operand);
 714             SymbolTable* symbolTable = nullptr;
 715
 716             switch (flag) {
 717             case ProfileTypeBytecodeClosureVar: {
 718                 const Identifier& ident = identifier(pc[4].u.operand);
 719                 int localScopeDepth = pc[2].u.operand;
 720                 ResolveType type = static_cast<ResolveType>(pc[5].u.operand);
 721                 // Even though type profiling may be profiling either a Get or a Put, we can always claim a Get because
 722                 // we're abstractly "read"ing from a JSScope.
 723                 ResolveOp op = JSScope::abstractResolve(m_globalObject->globalExec(), localScopeDepth, scope, ident, Get, type, InitializationMode::NotInitialization);
 724
 725                 if (op.type == ClosureVar || op.type == ModuleVar)
 726                     symbolTable = op.lexicalEnvironment->symbolTable();
 727                 else if (op.type == GlobalVar)
 728                     symbolTable = m_globalObject.get()->symbolTable();
 729
 730                 UniquedStringImpl* impl = (op.type == ModuleVar) ? op.importedName.get() : ident.impl();
 731                 if (symbolTable) {
 732                     ConcurrentJSLocker locker(symbolTable->m_lock);
 733                     // If our parent scope was created while profiling was disabled, it will not have prepared for profiling yet.
 734                     symbolTable->prepareForTypeProfiling(locker);
 735                     globalVariableID = symbolTable->uniqueIDForVariable(locker, impl, vm);
 736                     globalTypeSet = symbolTable->globalTypeSetForVariable(locker, impl, vm);
 737                 } else
 738                     globalVariableID = TypeProfilerNoGlobalIDExists;
 739
 740                 break;
 741             }
 742             case ProfileTypeBytecodeLocallyResolved: {
 743                 int symbolTableIndex = pc[2].u.operand;
 744                 SymbolTable* symbolTable = jsCast<SymbolTable*>(getConstant(symbolTableIndex));
 745                 const Identifier& ident = identifier(pc[4].u.operand);
 746                 ConcurrentJSLocker locker(symbolTable->m_lock);
 747                 // If our parent scope was created while profiling was disabled, it will not have prepared for profiling yet.
 748                 globalVariableID = symbolTable->uniqueIDForVariable(locker, ident.impl(), vm);
 749                 globalTypeSet = symbolTable->globalTypeSetForVariable(locker, ident.impl(), vm);
 750
 751                 break;
 752             }
 753             case ProfileTypeBytecodeDoesNotHaveGlobalID:
 754             case ProfileTypeBytecodeFunctionArgument: {
 755                 globalVariableID = TypeProfilerNoGlobalIDExists;
 756                 break;
 757             }
 758             case ProfileTypeBytecodeFunctionReturnStatement: {
 759                 RELEASE_ASSERT(ownerExecutable->isFunctionExecutable());
 760                 globalTypeSet = jsCast<FunctionExecutable*>(ownerExecutable)->returnStatementTypeSet();
 761                 globalVariableID = TypeProfilerReturnStatement;
 762                 if (!shouldAnalyze) {
 763                     // Because a return statement can be added implicitly to return undefined at the end of a function,
 764                     // and these nodes don't emit expression ranges because they aren't in the actual source text of
 765                     // the user's program, give the type profiler some range to identify these return statements.
 766                     // Currently, the text offset that is used as identification is "f" in the function keyword
 767                     // and is stored on TypeLocation's m_divotForFunctionOffsetIfReturnStatement member variable.
 768                     divotStart = divotEnd = ownerExecutable->typeProfilingStartOffset();
 769                     shouldAnalyze = true;
 770                 }
 771                 break;
 772             }
 773             }
 774
 775             std::pair<TypeLocation*, bool> locationPair = vm.typeProfiler()->typeLocationCache()->getTypeLocation(globalVariableID,
 776                 ownerExecutable->sourceID(), divotStart, divotEnd, WTFMove(globalTypeSet), &vm);
 777             TypeLocation* location = locationPair.first;
 778             bool isNewLocation = locationPair.second;
 779
 780             if (flag == ProfileTypeBytecodeFunctionReturnStatement)
 781                 location->m_divotForFunctionOffsetIfReturnStatement = ownerExecutable->typeProfilingStartOffset();
 782
 783             if (shouldAnalyze && isNewLocation)
 784                 vm.typeProfiler()->insertNewLocation(location);
 785
 786             instructions[i + 2].u.location = location;
 787             break;
 788         }
 789
 790         case op_debug: {
 791             if (pc[1].u.unsignedValue == DidReachBreakpoint)
 792                 m_hasDebuggerStatement = true;
 793             break;
 794         }
 795
 796         case op_create_rest: {
 797             int numberOfArgumentsToSkip = instructions[i + 3].u.operand;
 798             ASSERT_UNUSED(numberOfArgumentsToSkip, numberOfArgumentsToSkip >= 0);
 799             // This is used when rematerializing the rest parameter during OSR exit in the FTL JIT.");
 800             m_numberOfArgumentsToSkip = numberOfArgumentsToSkip;
 801             break;
 802         }
 803
 804         default:
 805             break;
 806         }
 807         i += opLength;
 808     }
 809
 810     if (vm.controlFlowProfiler())
 811         insertBasicBlockBoundariesForControlFlowProfiler(instructions);
 812
 813     m_instructions = WTFMove(instructions);
 814
 815     // Set optimization thresholds only after m_instructions is initialized, since these
 816     // rely on the instruction count (and are in theory permitted to also inspect the
 817     // instruction stream to more accurate assess the cost of tier-up).
 818     optimizeAfterWarmUp();
 819     jitAfterWarmUp();
 820
 821     // If the concurrent thread will want the code block's hash, then compute it here
 822     // synchronously.
 823     if (Options::alwaysComputeHash())
 824         hash();
 825
 826     if (Options::dumpGeneratedBytecodes())
 827         dumpBytecode();
 828
 829     heap()->m_codeBlocks->add(this);
 830     heap()->reportExtraMemoryAllocated(m_instructions.size() * sizeof(Instruction));
 831
 832     return true;
 833 }
 834
 835 CodeBlock::~CodeBlock()
 836 {
 837     if (m_vm->m_perBytecodeProfiler)
 838         m_vm->m_perBytecodeProfiler->notifyDestruction(this);
 839
 840     if (unlinkedCodeBlock()->didOptimize() == MixedTriState)
 841         unlinkedCodeBlock()->setDidOptimize(FalseTriState);
 842
 843 #if ENABLE(VERBOSE_VALUE_PROFILE)
 844     dumpValueProfiles();
 845 #endif
 846
 847     // We may be destroyed before any CodeBlocks that refer to us are destroyed.
 848     // Consider that two CodeBlocks become unreachable at the same time. There
 849     // is no guarantee about the order in which the CodeBlocks are destroyed.
 850     // So, if we don't remove incoming calls, and get destroyed before the
 851     // CodeBlock(s) that have calls into us, then the CallLinkInfo vector's
 852     // destructor will try to remove nodes from our (no longer valid) linked list.
 853     unlinkIncomingCalls();
 854
 855     // Note that our outgoing calls will be removed from other CodeBlocks'
 856     // m_incomingCalls linked lists through the execution of the ~CallLinkInfo
 857     // destructors.
 858
 859 #if ENABLE(JIT)
 860     for (Bag<StructureStubInfo>::iterator iter = m_stubInfos.begin(); !!iter; ++iter) {
 861         StructureStubInfo* stub = *iter;
 862         stub->aboutToDie();
 863         stub->deref();
 864     }
 865 #endif // ENABLE(JIT)
 866 }
 867
 868 bool CodeBlock::setConstantIdentifierSetRegisters(VM& vm, const Vector<ConstantIndentifierSetEntry>& constants)
 869 {
 870     auto scope = DECLARE_THROW_SCOPE(vm);
 871     JSGlobalObject* globalObject = m_globalObject.get();
 872     ExecState* exec = globalObject->globalExec();
 873
 874     for (const auto& entry : constants) {
 875         Structure* setStructure = globalObject->setStructure();
 876         RETURN_IF_EXCEPTION(scope, false);
 877         JSSet* jsSet = JSSet::create(exec, vm, setStructure);
 878         RETURN_IF_EXCEPTION(scope, false);
 879
 880         const IdentifierSet& set = entry.first;
 881         for (auto& setEntry : set) {
 882             JSString* jsString = jsOwnedString(&vm, setEntry.get());
 883             jsSet->add(exec, JSValue(jsString));
 884             RETURN_IF_EXCEPTION(scope, false);
 885         }
 886         m_constantRegisters[entry.second].set(vm, this, JSValue(jsSet));
 887     }
 888
 889     scope.release();
 890     return true;
 891 }
 892
 893 void CodeBlock::setConstantRegisters(const Vector<WriteBarrier<Unknown>>& constants, const Vector<SourceCodeRepresentation>& constantsSourceCodeRepresentation)
 894 {
 895     ASSERT(constants.size() == constantsSourceCodeRepresentation.size());
 896     size_t count = constants.size();
 897     m_constantRegisters.resizeToFit(count);
 898     bool hasTypeProfiler = !!m_vm->typeProfiler();
 899     for (size_t i = 0; i < count; i++) {
 900         JSValue constant = constants[i].get();
 901
 902         if (!constant.isEmpty()) {
 903             if (SymbolTable* symbolTable = jsDynamicCast<SymbolTable*>(*vm(), constant)) {
 904                 if (hasTypeProfiler) {
 905                     ConcurrentJSLocker locker(symbolTable->m_lock);
 906                     symbolTable->prepareForTypeProfiling(locker);
 907                 }
 908
 909                 SymbolTable* clone = symbolTable->cloneScopePart(*m_vm);
 910                 if (wasCompiledWithDebuggingOpcodes())
 911                     clone->setRareDataCodeBlock(this);
 912
 913                 constant = clone;
 914             }
 915         }
 916
 917         m_constantRegisters[i].set(*m_vm, this, constant);
 918     }
 919
 920     m_constantsSourceCodeRepresentation = constantsSourceCodeRepresentation;
 921 }
 922
 923 void CodeBlock::setAlternative(VM& vm, CodeBlock* alternative)
 924 {
 925     m_alternative.set(vm, this, alternative);
 926 }
 927
 928 void CodeBlock::setNumParameters(int newValue)
 929 {
 930     m_numParameters = newValue;
 931
 932     m_argumentValueProfiles = RefCountedArray<ValueProfile>(newValue);
 933 }
 934
 935 CodeBlock* CodeBlock::specialOSREntryBlockOrNull()
 936 {
 937 #if ENABLE(FTL_JIT)
 938     if (jitType() != JITCode::DFGJIT)
 939         return 0;
 940     DFG::JITCode* jitCode = m_jitCode->dfg();
 941     return jitCode->osrEntryBlock();
 942 #else // ENABLE(FTL_JIT)
 943     return 0;
 944 #endif // ENABLE(FTL_JIT)
 945 }
 946
 947 void CodeBlock::visitWeakly(SlotVisitor& visitor)
 948 {
 949     ConcurrentJSLocker locker(m_lock);
 950     if (m_visitWeaklyHasBeenCalled)
 951         return;
 952
 953     m_visitWeaklyHasBeenCalled = true;
 954
 955     if (Heap::isMarkedConcurrently(this))
 956         return;
 957
 958     if (shouldVisitStrongly(locker)) {
 959         visitor.appendUnbarriered(this);
 960         return;
 961     }
 962
 963     // There are two things that may use unconditional finalizers: inline cache clearing
 964     // and jettisoning. The probability of us wanting to do at least one of those things
 965     // is probably quite close to 1. So we add one no matter what and when it runs, it
 966     // figures out whether it has any work to do.
 967     visitor.addUnconditionalFinalizer(&m_unconditionalFinalizer);
 968
 969     if (!JITCode::isOptimizingJIT(jitType()))
 970         return;
 971
 972     // If we jettison ourselves we'll install our alternative, so make sure that it
 973     // survives GC even if we don't.
 974     visitor.append(m_alternative);
 975
 976     // There are two things that we use weak reference harvesters for: DFG fixpoint for
 977     // jettisoning, and trying to find structures that would be live based on some
 978     // inline cache. So it makes sense to register them regardless.
 979     visitor.addWeakReferenceHarvester(&m_weakReferenceHarvester);
 980
 981 #if ENABLE(DFG_JIT)
 982     // We get here if we're live in the sense that our owner executable is live,
 983     // but we're not yet live for sure in another sense: we may yet decide that this
 984     // code block should be jettisoned based on its outgoing weak references being
 985     // stale. Set a flag to indicate that we're still assuming that we're dead, and
 986     // perform one round of determining if we're live. The GC may determine, based on
 987     // either us marking additional objects, or by other objects being marked for
 988     // other reasons, that this iteration should run again; it will notify us of this
 989     // decision by calling harvestWeakReferences().
 990
 991     m_allTransitionsHaveBeenMarked = false;
 992     propagateTransitions(locker, visitor);
 993
 994     m_jitCode->dfgCommon()->livenessHasBeenProved = false;
 995     determineLiveness(locker, visitor);
 996 #endif // ENABLE(DFG_JIT)
 997 }
 998
 999 size_t CodeBlock::estimatedSize(JSCell* cell)
1000 {
1001     CodeBlock* thisObject = jsCast<CodeBlock*>(cell);
1002     size_t extraMemoryAllocated = thisObject->m_instructions.size() * sizeof(Instruction);
1003     if (thisObject->m_jitCode)
1004         extraMemoryAllocated += thisObject->m_jitCode->size();
1005     return Base::estimatedSize(cell) + extraMemoryAllocated;
1006 }
1007
1008 void CodeBlock::visitChildren(JSCell* cell, SlotVisitor& visitor)
1009 {
1010     CodeBlock* thisObject = jsCast<CodeBlock*>(cell);
1011     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
1012     JSCell::visitChildren(thisObject, visitor);
1013     thisObject->visitChildren(visitor);
1014 }
1015
1016 void CodeBlock::visitChildren(SlotVisitor& visitor)
1017 {
1018     ConcurrentJSLocker locker(m_lock);
1019     // There are two things that may use unconditional finalizers: inline cache clearing
1020     // and jettisoning. The probability of us wanting to do at least one of those things
1021     // is probably quite close to 1. So we add one no matter what and when it runs, it
1022     // figures out whether it has any work to do.
1023     visitor.addUnconditionalFinalizer(&m_unconditionalFinalizer);
1024
1025     if (CodeBlock* otherBlock = specialOSREntryBlockOrNull())
1026         visitor.appendUnbarriered(otherBlock);
1027
1028     if (m_jitCode)
1029         visitor.reportExtraMemoryVisited(m_jitCode->size());
1030     if (m_instructions.size()) {
1031         unsigned refCount = m_instructions.refCount();
1032         if (!refCount) {
1033             dataLog("CodeBlock: ", RawPointer(this), "\n");
1034             dataLog("m_instructions.data(): ", RawPointer(m_instructions.data()), "\n");
1035             dataLog("refCount: ", refCount, "\n");
1036             RELEASE_ASSERT_NOT_REACHED();
1037         }
1038         visitor.reportExtraMemoryVisited(m_instructions.size() * sizeof(Instruction) / refCount);
1039     }
1040
1041     stronglyVisitStrongReferences(locker, visitor);
1042     stronglyVisitWeakReferences(locker, visitor);
1043
1044     m_allTransitionsHaveBeenMarked = false;
1045     propagateTransitions(locker, visitor);
1046 }
1047
1048 bool CodeBlock::shouldVisitStrongly(const ConcurrentJSLocker& locker)
1049 {
1050     if (Options::forceCodeBlockLiveness())
1051         return true;
1052
1053     if (shouldJettisonDueToOldAge(locker))
1054         return false;
1055
1056     // Interpreter and Baseline JIT CodeBlocks don't need to be jettisoned when
1057     // their weak references go stale. So if a basline JIT CodeBlock gets
1058     // scanned, we can assume that this means that it's live.
1059     if (!JITCode::isOptimizingJIT(jitType()))
1060         return true;
1061
1062     return false;
1063 }
1064
1065 bool CodeBlock::shouldJettisonDueToWeakReference()
1066 {
1067     if (!JITCode::isOptimizingJIT(jitType()))
1068         return false;
1069     return !Heap::isMarked(this);
1070 }
1071
1072 static std::chrono::milliseconds timeToLive(JITCode::JITType jitType)
1073 {
1074     if (UNLIKELY(Options::useEagerCodeBlockJettisonTiming())) {
1075         switch (jitType) {
1076         case JITCode::InterpreterThunk:
1077             return std::chrono::milliseconds(10);
1078         case JITCode::BaselineJIT:
1079             return std::chrono::milliseconds(10 + 20);
1080         case JITCode::DFGJIT:
1081             return std::chrono::milliseconds(40);
1082         case JITCode::FTLJIT:
1083             return std::chrono::milliseconds(120);
1084         default:
1085             return std::chrono::milliseconds::max();
1086         }
1087     }
1088
1089     switch (jitType) {
1090     case JITCode::InterpreterThunk:
1091         return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::seconds(5));
1092     case JITCode::BaselineJIT:
1093         // Effectively 10 additional seconds, since BaselineJIT and
1094         // InterpreterThunk share a CodeBlock.
1095         return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::seconds(5 + 10));
1096     case JITCode::DFGJIT:
1097         return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::seconds(20));
1098     case JITCode::FTLJIT:
1099         return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::seconds(60));
1100     default:
1101         return std::chrono::milliseconds::max();
1102     }
1103 }
1104
1105 bool CodeBlock::shouldJettisonDueToOldAge(const ConcurrentJSLocker&)
1106 {
1107     if (Heap::isMarkedConcurrently(this))
1108         return false;
1109
1110     if (UNLIKELY(Options::forceCodeBlockToJettisonDueToOldAge()))
1111         return true;
1112
1113     if (timeSinceCreation() < timeToLive(jitType()))
1114         return false;
1115
1116     return true;
1117 }
1118
1119 #if ENABLE(DFG_JIT)
1120 static bool shouldMarkTransition(DFG::WeakReferenceTransition& transition)
1121 {
1122     if (transition.m_codeOrigin && !Heap::isMarkedConcurrently(transition.m_codeOrigin.get()))
1123         return false;
1124
1125     if (!Heap::isMarkedConcurrently(transition.m_from.get()))
1126         return false;
1127
1128     return true;
1129 }
1130 #endif // ENABLE(DFG_JIT)
1131
1132 void CodeBlock::propagateTransitions(const ConcurrentJSLocker&, SlotVisitor& visitor)
1133 {
1134     UNUSED_PARAM(visitor);
1135
1136     if (m_allTransitionsHaveBeenMarked)
1137         return;
1138
1139     bool allAreMarkedSoFar = true;
1140
1141     Interpreter* interpreter = m_vm->interpreter;
1142     if (jitType() == JITCode::InterpreterThunk) {
1143         const Vector<unsigned>& propertyAccessInstructions = m_unlinkedCode->propertyAccessInstructions();
1144         for (size_t i = 0; i < propertyAccessInstructions.size(); ++i) {
1145             Instruction* instruction = &instructions()[propertyAccessInstructions[i]];
1146             switch (interpreter->getOpcodeID(instruction[0])) {
1147             case op_put_by_id: {
1148                 StructureID oldStructureID = instruction[4].u.structureID;
1149                 StructureID newStructureID = instruction[6].u.structureID;
1150                 if (!oldStructureID || !newStructureID)
1151                     break;
1152                 Structure* oldStructure =
1153                     m_vm->heap.structureIDTable().get(oldStructureID);
1154                 Structure* newStructure =
1155                     m_vm->heap.structureIDTable().get(newStructureID);
1156                 if (Heap::isMarkedConcurrently(oldStructure))
1157                     visitor.appendUnbarriered(newStructure);
1158                 else
1159                     allAreMarkedSoFar = false;
1160                 break;
1161             }
1162             default:
1163                 break;
1164             }
1165         }
1166     }
1167
1168 #if ENABLE(JIT)
1169     if (JITCode::isJIT(jitType())) {
1170         for (Bag<StructureStubInfo>::iterator iter = m_stubInfos.begin(); !!iter; ++iter)
1171             allAreMarkedSoFar &= (*iter)->propagateTransitions(visitor);
1172     }
1173 #endif // ENABLE(JIT)
1174
1175 #if ENABLE(DFG_JIT)
1176     if (JITCode::isOptimizingJIT(jitType())) {
1177         DFG::CommonData* dfgCommon = m_jitCode->dfgCommon();
1178         for (auto& weakReference : dfgCommon->weakStructureReferences)
1179             allAreMarkedSoFar &= weakReference->markIfCheap(visitor);
1180
1181         for (auto& transition : dfgCommon->transitions) {
1182             if (shouldMarkTransition(transition)) {
1183                 // If the following three things are live, then the target of the
1184                 // transition is also live:
1185                 //
1186                 // - This code block. We know it's live already because otherwise
1187                 //   we wouldn't be scanning ourselves.
1188                 //
1189                 // - The code origin of the transition. Transitions may arise from
1190                 //   code that was inlined. They are not relevant if the user's
1191                 //   object that is required for the inlinee to run is no longer
1192                 //   live.
1193                 //
1194                 // - The source of the transition. The transition checks if some
1195                 //   heap location holds the source, and if so, stores the target.
1196                 //   Hence the source must be live for the transition to be live.
1197                 //
1198                 // We also short-circuit the liveness if the structure is harmless
1199                 // to mark (i.e. its global object and prototype are both already
1200                 // live).
1201
1202                 visitor.append(transition.m_to);
1203             } else
1204                 allAreMarkedSoFar = false;
1205         }
1206     }
1207 #endif // ENABLE(DFG_JIT)
1208
1209     if (allAreMarkedSoFar)
1210         m_allTransitionsHaveBeenMarked = true;
1211 }
1212
1213 void CodeBlock::determineLiveness(const ConcurrentJSLocker&, SlotVisitor& visitor)
1214 {
1215     UNUSED_PARAM(visitor);
1216
1217 #if ENABLE(DFG_JIT)
1218     // Check if we have any remaining work to do.
1219     DFG::CommonData* dfgCommon = m_jitCode->dfgCommon();
1220     if (dfgCommon->livenessHasBeenProved)
1221         return;
1222
1223     // Now check all of our weak references. If all of them are live, then we
1224     // have proved liveness and so we scan our strong references. If at end of
1225     // GC we still have not proved liveness, then this code block is toast.
1226     bool allAreLiveSoFar = true;
1227     for (unsigned i = 0; i < dfgCommon->weakReferences.size(); ++i) {
1228         JSCell* reference = dfgCommon->weakReferences[i].get();
1229         ASSERT(!jsDynamicCast<CodeBlock*>(*reference->vm(), reference));
1230         if (!Heap::isMarkedConcurrently(reference)) {
1231             allAreLiveSoFar = false;
1232             break;
1233         }
1234     }
1235     if (allAreLiveSoFar) {
1236         for (unsigned i = 0; i < dfgCommon->weakStructureReferences.size(); ++i) {
1237             if (!Heap::isMarkedConcurrently(dfgCommon->weakStructureReferences[i].get())) {
1238                 allAreLiveSoFar = false;
1239                 break;
1240             }
1241         }
1242     }
1243
1244     // If some weak references are dead, then this fixpoint iteration was
1245     // unsuccessful.
1246     if (!allAreLiveSoFar)
1247         return;
1248
1249     // All weak references are live. Record this information so we don't
1250     // come back here again, and scan the strong references.
1251     dfgCommon->livenessHasBeenProved = true;
1252     visitor.appendUnbarriered(this);
1253 #endif // ENABLE(DFG_JIT)
1254 }
1255
1256 void CodeBlock::WeakReferenceHarvester::visitWeakReferences(SlotVisitor& visitor)
1257 {
1258     CodeBlock* codeBlock =
1259         bitwise_cast<CodeBlock*>(
1260             bitwise_cast<char*>(this) - OBJECT_OFFSETOF(CodeBlock, m_weakReferenceHarvester));
1261
1262     codeBlock->propagateTransitions(NoLockingNecessary, visitor);
1263     codeBlock->determineLiveness(NoLockingNecessary, visitor);
1264 }
1265
1266 void CodeBlock::clearLLIntGetByIdCache(Instruction* instruction)
1267 {
1268     instruction[0].u.opcode = LLInt::getOpcode(op_get_by_id);
1269     instruction[4].u.pointer = nullptr;
1270     instruction[5].u.pointer = nullptr;
1271     instruction[6].u.pointer = nullptr;
1272 }
1273
1274 void CodeBlock::finalizeLLIntInlineCaches()
1275 {
1276     Interpreter* interpreter = m_vm->interpreter;
1277     const Vector<unsigned>& propertyAccessInstructions = m_unlinkedCode->propertyAccessInstructions();
1278     for (size_t size = propertyAccessInstructions.size(), i = 0; i < size; ++i) {
1279         Instruction* curInstruction = &instructions()[propertyAccessInstructions[i]];
1280         switch (interpreter->getOpcodeID(curInstruction[0])) {
1281         case op_get_by_id:
1282         case op_get_by_id_proto_load:
1283         case op_get_by_id_unset: {
1284             StructureID oldStructureID = curInstruction[4].u.structureID;
1285             if (!oldStructureID || Heap::isMarked(m_vm->heap.structureIDTable().get(oldStructureID)))
1286                 break;
1287             if (Options::verboseOSR())
1288                 dataLogF("Clearing LLInt property access.\n");
1289             clearLLIntGetByIdCache(curInstruction);
1290             break;
1291         }
1292         case op_put_by_id: {
1293             StructureID oldStructureID = curInstruction[4].u.structureID;
1294             StructureID newStructureID = curInstruction[6].u.structureID;
1295             StructureChain* chain = curInstruction[7].u.structureChain.get();
1296             if ((!oldStructureID || Heap::isMarked(m_vm->heap.structureIDTable().get(oldStructureID))) &&
1297                 (!newStructureID || Heap::isMarked(m_vm->heap.structureIDTable().get(newStructureID))) &&
1298                 (!chain || Heap::isMarked(chain)))
1299                 break;
1300             if (Options::verboseOSR())
1301                 dataLogF("Clearing LLInt put transition.\n");
1302             curInstruction[4].u.structureID = 0;
1303             curInstruction[5].u.operand = 0;
1304             curInstruction[6].u.structureID = 0;
1305             curInstruction[7].u.structureChain.clear();
1306             break;
1307         }
1308         case op_get_array_length:
1309             break;
1310         case op_to_this:
1311             if (!curInstruction[2].u.structure || Heap::isMarked(curInstruction[2].u.structure.get()))
1312                 break;
1313             if (Options::verboseOSR())
1314                 dataLogF("Clearing LLInt to_this with structure %p.\n", curInstruction[2].u.structure.get());
1315             curInstruction[2].u.structure.clear();
1316             curInstruction[3].u.toThisStatus = merge(
1317                 curInstruction[3].u.toThisStatus, ToThisClearedByGC);
1318             break;
1319         case op_create_this: {
1320             auto& cacheWriteBarrier = curInstruction[4].u.jsCell;
1321             if (!cacheWriteBarrier || cacheWriteBarrier.unvalidatedGet() == JSCell::seenMultipleCalleeObjects())
1322                 break;
1323             JSCell* cachedFunction = cacheWriteBarrier.get();
1324             if (Heap::isMarked(cachedFunction))
1325                 break;
1326             if (Options::verboseOSR())
1327                 dataLogF("Clearing LLInt create_this with cached callee %p.\n", cachedFunction);
1328             cacheWriteBarrier.clear();
1329             break;
1330         }
1331         case op_resolve_scope: {
1332             // Right now this isn't strictly necessary. Any symbol tables that this will refer to
1333             // are for outer functions, and we refer to those functions strongly, and they refer
1334             // to the symbol table strongly. But it's nice to be on the safe side.
1335             WriteBarrierBase<SymbolTable>& symbolTable = curInstruction[6].u.symbolTable;
1336             if (!symbolTable || Heap::isMarked(symbolTable.get()))
1337                 break;
1338             if (Options::verboseOSR())
1339                 dataLogF("Clearing dead symbolTable %p.\n", symbolTable.get());
1340             symbolTable.clear();
1341             break;
1342         }
1343         case op_get_from_scope:
1344         case op_put_to_scope: {
1345             GetPutInfo getPutInfo = GetPutInfo(curInstruction[4].u.operand);
1346             if (getPutInfo.resolveType() == GlobalVar || getPutInfo.resolveType() == GlobalVarWithVarInjectionChecks
1347                 || getPutInfo.resolveType() == LocalClosureVar || getPutInfo.resolveType() == GlobalLexicalVar || getPutInfo.resolveType() == GlobalLexicalVarWithVarInjectionChecks)
1348                 continue;
1349             WriteBarrierBase<Structure>& structure = curInstruction[5].u.structure;
1350             if (!structure || Heap::isMarked(structure.get()))
1351                 break;
1352             if (Options::verboseOSR())
1353                 dataLogF("Clearing scope access with structure %p.\n", structure.get());
1354             structure.clear();
1355             break;
1356         }
1357         default:
1358             OpcodeID opcodeID = interpreter->getOpcodeID(curInstruction[0]);
1359             ASSERT_WITH_MESSAGE_UNUSED(opcodeID, false, "Unhandled opcode in CodeBlock::finalizeUnconditionally, %s(%d) at bc %u", opcodeNames[opcodeID], opcodeID, propertyAccessInstructions[i]);
1360         }
1361     }
1362
1363     // We can't just remove all the sets when we clear the caches since we might have created a watchpoint set
1364     // then cleared the cache without GCing in between.
1365     m_llintGetByIdWatchpointMap.removeIf([](const StructureWatchpointMap::KeyValuePairType& pair) -> bool {
1366         return !Heap::isMarked(pair.key);
1367     });
1368
1369     for (unsigned i = 0; i < m_llintCallLinkInfos.size(); ++i) {
1370         if (m_llintCallLinkInfos[i].isLinked() && !Heap::isMarked(m_llintCallLinkInfos[i].callee.get())) {
1371             if (Options::verboseOSR())
1372                 dataLog("Clearing LLInt call from ", *this, "\n");
1373             m_llintCallLinkInfos[i].unlink();
1374         }
1375         if (!!m_llintCallLinkInfos[i].lastSeenCallee && !Heap::isMarked(m_llintCallLinkInfos[i].lastSeenCallee.get()))
1376             m_llintCallLinkInfos[i].lastSeenCallee.clear();
1377     }
1378 }
1379
1380 void CodeBlock::finalizeBaselineJITInlineCaches()
1381 {
1382 #if ENABLE(JIT)
1383     for (auto iter = callLinkInfosBegin(); !!iter; ++iter)
1384         (*iter)->visitWeak(*vm());
1385
1386     for (Bag<StructureStubInfo>::iterator iter = m_stubInfos.begin(); !!iter; ++iter) {
1387         StructureStubInfo& stubInfo = **iter;
1388         stubInfo.visitWeakReferences(this);
1389     }
1390 #endif
1391 }
1392
1393 void CodeBlock::UnconditionalFinalizer::finalizeUnconditionally()
1394 {
1395     CodeBlock* codeBlock = bitwise_cast<CodeBlock*>(
1396         bitwise_cast<char*>(this) - OBJECT_OFFSETOF(CodeBlock, m_unconditionalFinalizer));
1397
1398     codeBlock->updateAllPredictions();
1399
1400     if (!Heap::isMarked(codeBlock)) {
1401         if (codeBlock->shouldJettisonDueToWeakReference())
1402             codeBlock->jettison(Profiler::JettisonDueToWeakReference);
1403         else
1404             codeBlock->jettison(Profiler::JettisonDueToOldAge);
1405         return;
1406     }
1407
1408     if (JITCode::couldBeInterpreted(codeBlock->jitType()))
1409         codeBlock->finalizeLLIntInlineCaches();
1410
1411 #if ENABLE(JIT)
1412     if (!!codeBlock->jitCode())
1413         codeBlock->finalizeBaselineJITInlineCaches();
1414 #endif
1415 }
1416
1417 void CodeBlock::getStubInfoMap(const ConcurrentJSLocker&, StubInfoMap& result)
1418 {
1419 #if ENABLE(JIT)
1420     if (JITCode::isJIT(jitType()))
1421         toHashMap(m_stubInfos, getStructureStubInfoCodeOrigin, result);
1422 #else
1423     UNUSED_PARAM(result);
1424 #endif
1425 }
1426
1427 void CodeBlock::getStubInfoMap(StubInfoMap& result)
1428 {
1429     ConcurrentJSLocker locker(m_lock);
1430     getStubInfoMap(locker, result);
1431 }
1432
1433 void CodeBlock::getCallLinkInfoMap(const ConcurrentJSLocker&, CallLinkInfoMap& result)
1434 {
1435 #if ENABLE(JIT)
1436     if (JITCode::isJIT(jitType()))
1437         toHashMap(m_callLinkInfos, getCallLinkInfoCodeOrigin, result);
1438 #else
1439     UNUSED_PARAM(result);
1440 #endif
1441 }
1442
1443 void CodeBlock::getCallLinkInfoMap(CallLinkInfoMap& result)
1444 {
1445     ConcurrentJSLocker locker(m_lock);
1446     getCallLinkInfoMap(locker, result);
1447 }
1448
1449 void CodeBlock::getByValInfoMap(const ConcurrentJSLocker&, ByValInfoMap& result)
1450 {
1451 #if ENABLE(JIT)
1452     if (JITCode::isJIT(jitType())) {
1453         for (auto* byValInfo : m_byValInfos)
1454             result.add(CodeOrigin(byValInfo->bytecodeIndex), byValInfo);
1455     }
1456 #else
1457     UNUSED_PARAM(result);
1458 #endif
1459 }
1460
1461 void CodeBlock::getByValInfoMap(ByValInfoMap& result)
1462 {
1463     ConcurrentJSLocker locker(m_lock);
1464     getByValInfoMap(locker, result);
1465 }
1466
1467 #if ENABLE(JIT)
1468 StructureStubInfo* CodeBlock::addStubInfo(AccessType accessType)
1469 {
1470     ConcurrentJSLocker locker(m_lock);
1471     return m_stubInfos.add(accessType);
1472 }
1473
1474 JITAddIC* CodeBlock::addJITAddIC(ArithProfile* arithProfile)
1475 {
1476     return m_addICs.add(arithProfile);
1477 }
1478
1479 JITMulIC* CodeBlock::addJITMulIC(ArithProfile* arithProfile)
1480 {
1481     return m_mulICs.add(arithProfile);
1482 }
1483
1484 JITSubIC* CodeBlock::addJITSubIC(ArithProfile* arithProfile)
1485 {
1486     return m_subICs.add(arithProfile);
1487 }
1488
1489 JITNegIC* CodeBlock::addJITNegIC(ArithProfile* arithProfile)
1490 {
1491     return m_negICs.add(arithProfile);
1492 }
1493
1494 StructureStubInfo* CodeBlock::findStubInfo(CodeOrigin codeOrigin)
1495 {
1496     for (StructureStubInfo* stubInfo : m_stubInfos) {
1497         if (stubInfo->codeOrigin == codeOrigin)
1498             return stubInfo;
1499     }
1500     return nullptr;
1501 }
1502
1503 ByValInfo* CodeBlock::addByValInfo()
1504 {
1505     ConcurrentJSLocker locker(m_lock);
1506     return m_byValInfos.add();
1507 }
1508
1509 CallLinkInfo* CodeBlock::addCallLinkInfo()
1510 {
1511     ConcurrentJSLocker locker(m_lock);
1512     return m_callLinkInfos.add();
1513 }
1514
1515 CallLinkInfo* CodeBlock::getCallLinkInfoForBytecodeIndex(unsigned index)
1516 {
1517     for (auto iter = m_callLinkInfos.begin(); !!iter; ++iter) {
1518         if ((*iter)->codeOrigin() == CodeOrigin(index))
1519             return *iter;
1520     }
1521     return nullptr;
1522 }
1523
1524 void CodeBlock::resetJITData()
1525 {
1526     RELEASE_ASSERT(!JITCode::isJIT(jitType()));
1527     ConcurrentJSLocker locker(m_lock);
1528
1529     // We can clear these because no other thread will have references to any stub infos, call
1530     // link infos, or by val infos if we don't have JIT code. Attempts to query these data
1531     // structures using the concurrent API (getStubInfoMap and friends) will return nothing if we
1532     // don't have JIT code.
1533     m_stubInfos.clear();
1534     m_callLinkInfos.clear();
1535     m_byValInfos.clear();
1536
1537     // We can clear this because the DFG's queries to these data structures are guarded by whether
1538     // there is JIT code.
1539     m_rareCaseProfiles.clear();
1540 }
1541 #endif
1542
1543 void CodeBlock::visitOSRExitTargets(const ConcurrentJSLocker&, SlotVisitor& visitor)
1544 {
1545     // We strongly visit OSR exits targets because we don't want to deal with
1546     // the complexity of generating an exit target CodeBlock on demand and
1547     // guaranteeing that it matches the details of the CodeBlock we compiled
1548     // the OSR exit against.
1549
1550     visitor.append(m_alternative);
1551
1552 #if ENABLE(DFG_JIT)
1553     DFG::CommonData* dfgCommon = m_jitCode->dfgCommon();
1554     if (dfgCommon->inlineCallFrames) {
1555         for (auto* inlineCallFrame : *dfgCommon->inlineCallFrames) {
1556             ASSERT(inlineCallFrame->baselineCodeBlock);
1557             visitor.append(inlineCallFrame->baselineCodeBlock);
1558         }
1559     }
1560 #endif
1561 }
1562
1563 void CodeBlock::stronglyVisitStrongReferences(const ConcurrentJSLocker& locker, SlotVisitor& visitor)
1564 {
1565     UNUSED_PARAM(locker);
1566
1567     visitor.append(m_globalObject);
1568     visitor.append(m_ownerExecutable);
1569     visitor.append(m_unlinkedCode);
1570     if (m_rareData)
1571         m_rareData->m_directEvalCodeCache.visitAggregate(visitor);
1572     visitor.appendValues(m_constantRegisters.data(), m_constantRegisters.size());
1573     for (auto& functionExpr : m_functionExprs)
1574         visitor.append(functionExpr);
1575     for (auto& functionDecl : m_functionDecls)
1576         visitor.append(functionDecl);
1577     for (auto& objectAllocationProfile : m_objectAllocationProfiles)
1578         objectAllocationProfile.visitAggregate(visitor);
1579
1580 #if ENABLE(JIT)
1581     for (ByValInfo* byValInfo : m_byValInfos)
1582         visitor.append(byValInfo->cachedSymbol);
1583 #endif
1584
1585 #if ENABLE(DFG_JIT)
1586     if (JITCode::isOptimizingJIT(jitType()))
1587         visitOSRExitTargets(locker, visitor);
1588 #endif
1589 }
1590
1591 void CodeBlock::stronglyVisitWeakReferences(const ConcurrentJSLocker&, SlotVisitor& visitor)
1592 {
1593     UNUSED_PARAM(visitor);
1594
1595 #if ENABLE(DFG_JIT)
1596     if (!JITCode::isOptimizingJIT(jitType()))
1597         return;
1598
1599     DFG::CommonData* dfgCommon = m_jitCode->dfgCommon();
1600
1601     for (auto& transition : dfgCommon->transitions) {
1602         if (!!transition.m_codeOrigin)
1603             visitor.append(transition.m_codeOrigin); // Almost certainly not necessary, since the code origin should also be a weak reference. Better to be safe, though.
1604         visitor.append(transition.m_from);
1605         visitor.append(transition.m_to);
1606     }
1607
1608     for (auto& weakReference : dfgCommon->weakReferences)
1609         visitor.append(weakReference);
1610
1611     for (auto& weakStructureReference : dfgCommon->weakStructureReferences)
1612         visitor.append(weakStructureReference);
1613
1614     dfgCommon->livenessHasBeenProved = true;
1615 #endif
1616 }
1617
1618 CodeBlock* CodeBlock::baselineAlternative()
1619 {
1620 #if ENABLE(JIT)
1621     CodeBlock* result = this;
1622     while (result->alternative())
1623         result = result->alternative();
1624     RELEASE_ASSERT(result);
1625     RELEASE_ASSERT(JITCode::isBaselineCode(result->jitType()) || result->jitType() == JITCode::None);
1626     return result;
1627 #else
1628     return this;
1629 #endif
1630 }
1631
1632 CodeBlock* CodeBlock::baselineVersion()
1633 {
1634 #if ENABLE(JIT)
1635     if (JITCode::isBaselineCode(jitType()))
1636         return this;
1637     CodeBlock* result = replacement();
1638     if (!result) {
1639         // This can happen if we're creating the original CodeBlock for an executable.
1640         // Assume that we're the baseline CodeBlock.
1641         RELEASE_ASSERT(jitType() == JITCode::None);
1642         return this;
1643     }
1644     result = result->baselineAlternative();
1645     return result;
1646 #else
1647     return this;
1648 #endif
1649 }
1650
1651 #if ENABLE(JIT)
1652 bool CodeBlock::hasOptimizedReplacement(JITCode::JITType typeToReplace)
1653 {
1654     return JITCode::isHigherTier(replacement()->jitType(), typeToReplace);
1655 }
1656
1657 bool CodeBlock::hasOptimizedReplacement()
1658 {
1659     return hasOptimizedReplacement(jitType());
1660 }
1661 #endif
1662
1663 HandlerInfo* CodeBlock::handlerForBytecodeOffset(unsigned bytecodeOffset, RequiredHandler requiredHandler)
1664 {
1665     RELEASE_ASSERT(bytecodeOffset < instructions().size());
1666     return handlerForIndex(bytecodeOffset, requiredHandler);
1667 }
1668
1669 HandlerInfo* CodeBlock::handlerForIndex(unsigned index, RequiredHandler requiredHandler)
1670 {
1671     if (!m_rareData)
1672         return 0;
1673     return HandlerInfo::handlerForIndex(m_rareData->m_exceptionHandlers, index, requiredHandler);
1674 }
1675
1676 CallSiteIndex CodeBlock::newExceptionHandlingCallSiteIndex(CallSiteIndex originalCallSite)
1677 {
1678 #if ENABLE(DFG_JIT)
1679     RELEASE_ASSERT(JITCode::isOptimizingJIT(jitType()));
1680     RELEASE_ASSERT(canGetCodeOrigin(originalCallSite));
1681     ASSERT(!!handlerForIndex(originalCallSite.bits()));
1682     CodeOrigin originalOrigin = codeOrigin(originalCallSite);
1683     return m_jitCode->dfgCommon()->addUniqueCallSiteIndex(originalOrigin);
1684 #else
1685     // We never create new on-the-fly exception handling
1686     // call sites outside the DFG/FTL inline caches.
1687     UNUSED_PARAM(originalCallSite);
1688     RELEASE_ASSERT_NOT_REACHED();
1689     return CallSiteIndex(0u);
1690 #endif
1691 }
1692
1693 void CodeBlock::removeExceptionHandlerForCallSite(CallSiteIndex callSiteIndex)
1694 {
1695     RELEASE_ASSERT(m_rareData);
1696     Vector<HandlerInfo>& exceptionHandlers = m_rareData->m_exceptionHandlers;
1697     unsigned index = callSiteIndex.bits();
1698     for (size_t i = 0; i < exceptionHandlers.size(); ++i) {
1699         HandlerInfo& handler = exceptionHandlers[i];
1700         if (handler.start <= index && handler.end > index) {
1701             exceptionHandlers.remove(i);
1702             return;
1703         }
1704     }
1705
1706     RELEASE_ASSERT_NOT_REACHED();
1707 }
1708
1709 unsigned CodeBlock::lineNumberForBytecodeOffset(unsigned bytecodeOffset)
1710 {
1711     RELEASE_ASSERT(bytecodeOffset < instructions().size());
1712     return ownerScriptExecutable()->firstLine() + m_unlinkedCode->lineNumberForBytecodeOffset(bytecodeOffset);
1713 }
1714
1715 unsigned CodeBlock::columnNumberForBytecodeOffset(unsigned bytecodeOffset)
1716 {
1717     int divot;
1718     int startOffset;
1719     int endOffset;
1720     unsigned line;
1721     unsigned column;
1722     expressionRangeForBytecodeOffset(bytecodeOffset, divot, startOffset, endOffset, line, column);
1723     return column;
1724 }
1725
1726 void CodeBlock::expressionRangeForBytecodeOffset(unsigned bytecodeOffset, int& divot, int& startOffset, int& endOffset, unsigned& line, unsigned& column) const
1727 {
1728     m_unlinkedCode->expressionRangeForBytecodeOffset(bytecodeOffset, divot, startOffset, endOffset, line, column);
1729     divot += m_sourceOffset;
1730     column += line ? 1 : firstLineColumnOffset();
1731     line += ownerScriptExecutable()->firstLine();
1732 }
1733
1734 bool CodeBlock::hasOpDebugForLineAndColumn(unsigned line, unsigned column)
1735 {
1736     Interpreter* interpreter = vm()->interpreter;
1737     const Instruction* begin = instructions().begin();
1738     const Instruction* end = instructions().end();
1739     for (const Instruction* it = begin; it != end;) {
1740         OpcodeID opcodeID = interpreter->getOpcodeID(*it);
1741         if (opcodeID == op_debug) {
1742             unsigned bytecodeOffset = it - begin;
1743             int unused;
1744             unsigned opDebugLine;
1745             unsigned opDebugColumn;
1746             expressionRangeForBytecodeOffset(bytecodeOffset, unused, unused, unused, opDebugLine, opDebugColumn);
1747             if (line == opDebugLine && (column == Breakpoint::unspecifiedColumn || column == opDebugColumn))
1748                 return true;
1749         }
1750         it += opcodeLengths[opcodeID];
1751     }
1752     return false;
1753 }
1754
1755 void CodeBlock::shrinkToFit(ShrinkMode shrinkMode)
1756 {
1757     ConcurrentJSLocker locker(m_lock);
1758
1759     m_rareCaseProfiles.shrinkToFit();
1760
1761     if (shrinkMode == EarlyShrink) {
1762         m_constantRegisters.shrinkToFit();
1763         m_constantsSourceCodeRepresentation.shrinkToFit();
1764
1765         if (m_rareData) {
1766             m_rareData->m_switchJumpTables.shrinkToFit();
1767             m_rareData->m_stringSwitchJumpTables.shrinkToFit();
1768         }
1769     } // else don't shrink these, because we would have already pointed pointers into these tables.
1770 }
1771
1772 #if ENABLE(JIT)
1773 void CodeBlock::linkIncomingCall(ExecState* callerFrame, CallLinkInfo* incoming)
1774 {
1775     noticeIncomingCall(callerFrame);
1776     m_incomingCalls.push(incoming);
1777 }
1778
1779 void CodeBlock::linkIncomingPolymorphicCall(ExecState* callerFrame, PolymorphicCallNode* incoming)
1780 {
1781     noticeIncomingCall(callerFrame);
1782     m_incomingPolymorphicCalls.push(incoming);
1783 }
1784 #endif // ENABLE(JIT)
1785
1786 void CodeBlock::unlinkIncomingCalls()
1787 {
1788     while (m_incomingLLIntCalls.begin() != m_incomingLLIntCalls.end())
1789         m_incomingLLIntCalls.begin()->unlink();
1790 #if ENABLE(JIT)
1791     while (m_incomingCalls.begin() != m_incomingCalls.end())
1792         m_incomingCalls.begin()->unlink(*vm());
1793     while (m_incomingPolymorphicCalls.begin() != m_incomingPolymorphicCalls.end())
1794         m_incomingPolymorphicCalls.begin()->unlink(*vm());
1795 #endif // ENABLE(JIT)
1796 }
1797
1798 void CodeBlock::linkIncomingCall(ExecState* callerFrame, LLIntCallLinkInfo* incoming)
1799 {
1800     noticeIncomingCall(callerFrame);
1801     m_incomingLLIntCalls.push(incoming);
1802 }
1803
1804 CodeBlock* CodeBlock::newReplacement()
1805 {
1806     return ownerScriptExecutable()->newReplacementCodeBlockFor(specializationKind());
1807 }
1808
1809 #if ENABLE(JIT)
1810 CodeBlock* CodeBlock::replacement()
1811 {
1812     const ClassInfo* classInfo = this->classInfo(*vm());
1813
1814     if (classInfo == FunctionCodeBlock::info())
1815         return jsCast<FunctionExecutable*>(ownerExecutable())->codeBlockFor(m_isConstructor ? CodeForConstruct : CodeForCall);
1816
1817     if (classInfo == EvalCodeBlock::info())
1818         return jsCast<EvalExecutable*>(ownerExecutable())->codeBlock();
1819
1820     if (classInfo == ProgramCodeBlock::info())
1821         return jsCast<ProgramExecutable*>(ownerExecutable())->codeBlock();
1822
1823     if (classInfo == ModuleProgramCodeBlock::info())
1824         return jsCast<ModuleProgramExecutable*>(ownerExecutable())->codeBlock();
1825
1826     RELEASE_ASSERT_NOT_REACHED();
1827     return nullptr;
1828 }
1829
1830 DFG::CapabilityLevel CodeBlock::computeCapabilityLevel()
1831 {
1832     const ClassInfo* classInfo = this->classInfo(*vm());
1833
1834     if (classInfo == FunctionCodeBlock::info()) {
1835         if (m_isConstructor)
1836             return DFG::functionForConstructCapabilityLevel(this);
1837         return DFG::functionForCallCapabilityLevel(this);
1838     }
1839
1840     if (classInfo == EvalCodeBlock::info())
1841         return DFG::evalCapabilityLevel(this);
1842
1843     if (classInfo == ProgramCodeBlock::info())
1844         return DFG::programCapabilityLevel(this);
1845
1846     if (classInfo == ModuleProgramCodeBlock::info())
1847         return DFG::programCapabilityLevel(this);
1848
1849     RELEASE_ASSERT_NOT_REACHED();
1850     return DFG::CannotCompile;
1851 }
1852
1853 #endif // ENABLE(JIT)
1854
1855 void CodeBlock::jettison(Profiler::JettisonReason reason, ReoptimizationMode mode, const FireDetail* detail)
1856 {
1857 #if !ENABLE(DFG_JIT)
1858     UNUSED_PARAM(mode);
1859     UNUSED_PARAM(detail);
1860 #endif
1861
1862     CODEBLOCK_LOG_EVENT(this, "jettison", ("due to ", reason, ", counting = ", mode == CountReoptimization, ", detail = ", pointerDump(detail)));
1863
1864     RELEASE_ASSERT(reason != Profiler::NotJettisoned);
1865
1866 #if ENABLE(DFG_JIT)
1867     if (DFG::shouldDumpDisassembly()) {
1868         dataLog("Jettisoning ", *this);
1869         if (mode == CountReoptimization)
1870             dataLog(" and counting reoptimization");
1871         dataLog(" due to ", reason);
1872         if (detail)
1873             dataLog(", ", *detail);
1874         dataLog(".\n");
1875     }
1876
1877     if (reason == Profiler::JettisonDueToWeakReference) {
1878         if (DFG::shouldDumpDisassembly()) {
1879             dataLog(*this, " will be jettisoned because of the following dead references:\n");
1880             DFG::CommonData* dfgCommon = m_jitCode->dfgCommon();
1881             for (auto& transition : dfgCommon->transitions) {
1882                 JSCell* origin = transition.m_codeOrigin.get();
1883                 JSCell* from = transition.m_from.get();
1884                 JSCell* to = transition.m_to.get();
1885                 if ((!origin || Heap::isMarked(origin)) && Heap::isMarked(from))
1886                     continue;
1887                 dataLog("    Transition under ", RawPointer(origin), ", ", RawPointer(from), " -> ", RawPointer(to), ".\n");
1888             }
1889             for (unsigned i = 0; i < dfgCommon->weakReferences.size(); ++i) {
1890                 JSCell* weak = dfgCommon->weakReferences[i].get();
1891                 if (Heap::isMarked(weak))
1892                     continue;
1893                 dataLog("    Weak reference ", RawPointer(weak), ".\n");
1894             }
1895         }
1896     }
1897 #endif // ENABLE(DFG_JIT)
1898
1899     DeferGCForAWhile deferGC(*heap());
1900
1901     // We want to accomplish two things here:
1902     // 1) Make sure that if this CodeBlock is on the stack right now, then if we return to it
1903     //    we should OSR exit at the top of the next bytecode instruction after the return.
1904     // 2) Make sure that if we call the owner executable, then we shouldn't call this CodeBlock.
1905
1906 #if ENABLE(DFG_JIT)
1907     if (reason != Profiler::JettisonDueToOldAge) {
1908         if (Profiler::Compilation* compilation = jitCode()->dfgCommon()->compilation.get())
1909             compilation->setJettisonReason(reason, detail);
1910
1911         // This accomplishes (1), and does its own book-keeping about whether it has already happened.
1912         if (!jitCode()->dfgCommon()->invalidate()) {
1913             // We've already been invalidated.
1914             RELEASE_ASSERT(this != replacement() || (m_vm->heap.isCurrentThreadBusy() && !Heap::isMarked(ownerScriptExecutable())));
1915             return;
1916         }
1917     }
1918
1919     if (DFG::shouldDumpDisassembly())
1920         dataLog("    Did invalidate ", *this, "\n");
1921
1922     // Count the reoptimization if that's what the user wanted.
1923     if (mode == CountReoptimization) {
1924         // FIXME: Maybe this should call alternative().
1925         // https://bugs.webkit.org/show_bug.cgi?id=123677
1926         baselineAlternative()->countReoptimization();
1927         if (DFG::shouldDumpDisassembly())
1928             dataLog("    Did count reoptimization for ", *this, "\n");
1929     }
1930
1931     if (this != replacement()) {
1932         // This means that we were never the entrypoint. This can happen for OSR entry code
1933         // blocks.
1934         return;
1935     }
1936
1937     if (alternative())
1938         alternative()->optimizeAfterWarmUp();
1939
1940     if (reason != Profiler::JettisonDueToOldAge && reason != Profiler::JettisonDueToVMTraps)
1941         tallyFrequentExitSites();
1942 #endif // ENABLE(DFG_JIT)
1943
1944     // Jettison can happen during GC. We don't want to install code to a dead executable
1945     // because that would add a dead object to the remembered set.
1946     if (m_vm->heap.isCurrentThreadBusy() && !Heap::isMarked(ownerScriptExecutable()))
1947         return;
1948
1949     // This accomplishes (2).
1950     ownerScriptExecutable()->installCode(
1951         m_globalObject->vm(), alternative(), codeType(), specializationKind());
1952
1953 #if ENABLE(DFG_JIT)
1954     if (DFG::shouldDumpDisassembly())
1955         dataLog("    Did install baseline version of ", *this, "\n");
1956 #endif // ENABLE(DFG_JIT)
1957 }
1958
1959 JSGlobalObject* CodeBlock::globalObjectFor(CodeOrigin codeOrigin)
1960 {
1961     if (!codeOrigin.inlineCallFrame)
1962         return globalObject();
1963     return codeOrigin.inlineCallFrame->baselineCodeBlock->globalObject();
1964 }
1965
1966 class RecursionCheckFunctor {
1967 public:
1968     RecursionCheckFunctor(CallFrame* startCallFrame, CodeBlock* codeBlock, unsigned depthToCheck)
1969         : m_startCallFrame(startCallFrame)
1970         , m_codeBlock(codeBlock)
1971         , m_depthToCheck(depthToCheck)
1972         , m_foundStartCallFrame(false)
1973         , m_didRecurse(false)
1974     { }
1975
1976     StackVisitor::Status operator()(StackVisitor& visitor) const
1977     {
1978         CallFrame* currentCallFrame = visitor->callFrame();
1979
1980         if (currentCallFrame == m_startCallFrame)
1981             m_foundStartCallFrame = true;
1982
1983         if (m_foundStartCallFrame) {
1984             if (visitor->callFrame()->codeBlock() == m_codeBlock) {
1985                 m_didRecurse = true;
1986                 return StackVisitor::Done;
1987             }
1988
1989             if (!m_depthToCheck--)
1990                 return StackVisitor::Done;
1991         }
1992
1993         return StackVisitor::Continue;
1994     }
1995
1996     bool didRecurse() const { return m_didRecurse; }
1997
1998 private:
1999     CallFrame* m_startCallFrame;
2000     CodeBlock* m_codeBlock;
2001     mutable unsigned m_depthToCheck;
2002     mutable bool m_foundStartCallFrame;
2003     mutable bool m_didRecurse;
2004 };
2005
2006 void CodeBlock::noticeIncomingCall(ExecState* callerFrame)
2007 {
2008     CodeBlock* callerCodeBlock = callerFrame->codeBlock();
2009
2010     if (Options::verboseCallLink())
2011         dataLog("Noticing call link from ", pointerDump(callerCodeBlock), " to ", *this, "\n");
2012
2013 #if ENABLE(DFG_JIT)
2014     if (!m_shouldAlwaysBeInlined)
2015         return;
2016
2017     if (!callerCodeBlock) {
2018         m_shouldAlwaysBeInlined = false;
2019         if (Options::verboseCallLink())
2020             dataLog("    Clearing SABI because caller is native.\n");
2021         return;
2022     }
2023
2024     if (!hasBaselineJITProfiling())
2025         return;
2026
2027     if (!DFG::mightInlineFunction(this))
2028         return;
2029
2030     if (!canInline(capabilityLevelState()))
2031         return;
2032
2033     if (!DFG::isSmallEnoughToInlineCodeInto(callerCodeBlock)) {
2034         m_shouldAlwaysBeInlined = false;
2035         if (Options::verboseCallLink())
2036             dataLog("    Clearing SABI because caller is too large.\n");
2037         return;
2038     }
2039
2040     if (callerCodeBlock->jitType() == JITCode::InterpreterThunk) {
2041         // If the caller is still in the interpreter, then we can't expect inlining to
2042         // happen anytime soon. Assume it's profitable to optimize it separately. This
2043         // ensures that a function is SABI only if it is called no more frequently than
2044         // any of its callers.
2045         m_shouldAlwaysBeInlined = false;
2046         if (Options::verboseCallLink())
2047             dataLog("    Clearing SABI because caller is in LLInt.\n");
2048         return;
2049     }
2050
2051     if (JITCode::isOptimizingJIT(callerCodeBlock->jitType())) {
2052         m_shouldAlwaysBeInlined = false;
2053         if (Options::verboseCallLink())
2054             dataLog("    Clearing SABI bcause caller was already optimized.\n");
2055         return;
2056     }
2057
2058     if (callerCodeBlock->codeType() != FunctionCode) {
2059         // If the caller is either eval or global code, assume that that won't be
2060         // optimized anytime soon. For eval code this is particularly true since we
2061         // delay eval optimization by a *lot*.
2062         m_shouldAlwaysBeInlined = false;
2063         if (Options::verboseCallLink())
2064             dataLog("    Clearing SABI because caller is not a function.\n");
2065         return;
2066     }
2067
2068     // Recursive calls won't be inlined.
2069     RecursionCheckFunctor functor(callerFrame, this, Options::maximumInliningDepth());
2070     vm()->topCallFrame->iterate(functor);
2071
2072     if (functor.didRecurse()) {
2073         if (Options::verboseCallLink())
2074             dataLog("    Clearing SABI because recursion was detected.\n");
2075         m_shouldAlwaysBeInlined = false;
2076         return;
2077     }
2078
2079     if (callerCodeBlock->capabilityLevelState() == DFG::CapabilityLevelNotSet) {
2080         dataLog("In call from ", FullCodeOrigin(callerCodeBlock, callerFrame->codeOrigin()), " to ", *this, ": caller's DFG capability level is not set.\n");
2081         CRASH();
2082     }
2083
2084     if (canCompile(callerCodeBlock->capabilityLevelState()))
2085         return;
2086
2087     if (Options::verboseCallLink())
2088         dataLog("    Clearing SABI because the caller is not a DFG candidate.\n");
2089
2090     m_shouldAlwaysBeInlined = false;
2091 #endif
2092 }
2093
2094 unsigned CodeBlock::reoptimizationRetryCounter() const
2095 {
2096 #if ENABLE(JIT)
2097     ASSERT(m_reoptimizationRetryCounter <= Options::reoptimizationRetryCounterMax());
2098     return m_reoptimizationRetryCounter;
2099 #else
2100     return 0;
2101 #endif // ENABLE(JIT)
2102 }
2103
2104 #if ENABLE(JIT)
2105 void CodeBlock::setCalleeSaveRegisters(RegisterSet calleeSaveRegisters)
2106 {
2107     m_calleeSaveRegisters = std::make_unique<RegisterAtOffsetList>(calleeSaveRegisters);
2108 }
2109
2110 void CodeBlock::setCalleeSaveRegisters(std::unique_ptr<RegisterAtOffsetList> registerAtOffsetList)
2111 {
2112     m_calleeSaveRegisters = WTFMove(registerAtOffsetList);
2113 }
2114
2115 static size_t roundCalleeSaveSpaceAsVirtualRegisters(size_t calleeSaveRegisters)
2116 {
2117     static const unsigned cpuRegisterSize = sizeof(void*);
2118     return (WTF::roundUpToMultipleOf(sizeof(Register), calleeSaveRegisters * cpuRegisterSize) / sizeof(Register));
2119
2120 }
2121
2122 size_t CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters()
2123 {
2124     return roundCalleeSaveSpaceAsVirtualRegisters(numberOfLLIntBaselineCalleeSaveRegisters());
2125 }
2126
2127 size_t CodeBlock::calleeSaveSpaceAsVirtualRegisters()
2128 {
2129     return roundCalleeSaveSpaceAsVirtualRegisters(m_calleeSaveRegisters->size());
2130 }
2131
2132 void CodeBlock::countReoptimization()
2133 {
2134     m_reoptimizationRetryCounter++;
2135     if (m_reoptimizationRetryCounter > Options::reoptimizationRetryCounterMax())
2136         m_reoptimizationRetryCounter = Options::reoptimizationRetryCounterMax();
2137 }
2138
2139 unsigned CodeBlock::numberOfDFGCompiles()
2140 {
2141     ASSERT(JITCode::isBaselineCode(jitType()));
2142     if (Options::testTheFTL()) {
2143         if (m_didFailFTLCompilation)
2144             return 1000000;
2145         return (m_hasBeenCompiledWithFTL ? 1 : 0) + m_reoptimizationRetryCounter;
2146     }
2147     return (JITCode::isOptimizingJIT(replacement()->jitType()) ? 1 : 0) + m_reoptimizationRetryCounter;
2148 }
2149
2150 int32_t CodeBlock::codeTypeThresholdMultiplier() const
2151 {
2152     if (codeType() == EvalCode)
2153         return Options::evalThresholdMultiplier();
2154
2155     return 1;
2156 }
2157
2158 double CodeBlock::optimizationThresholdScalingFactor()
2159 {
2160     // This expression arises from doing a least-squares fit of
2161     //
2162     // F[x_] =: a * Sqrt[x + b] + Abs[c * x] + d
2163     //
2164     // against the data points:
2165     //
2166     //    x       F[x_]
2167     //    10       0.9          (smallest reasonable code block)
2168     //   200       1.0          (typical small-ish code block)
2169     //   320       1.2          (something I saw in 3d-cube that I wanted to optimize)
2170     //  1268       5.0          (something I saw in 3d-cube that I didn't want to optimize)
2171     //  4000       5.5          (random large size, used to cause the function to converge to a shallow curve of some sort)
2172     // 10000       6.0          (similar to above)
2173     //
2174     // I achieve the minimization using the following Mathematica code:
2175     //
2176     // MyFunctionTemplate[x_, a_, b_, c_, d_] := a*Sqrt[x + b] + Abs[c*x] + d
2177     //
2178     // samples = {{10, 0.9}, {200, 1}, {320, 1.2}, {1268, 5}, {4000, 5.5}, {10000, 6}}
2179     //
2180     // solution =
2181     //     Minimize[Plus @@ ((MyFunctionTemplate[#[[1]], a, b, c, d] - #[[2]])^2 & /@ samples),
2182     //         {a, b, c, d}][[2]]
2183     //
2184     // And the code below (to initialize a, b, c, d) is generated by:
2185     //
2186     // Print["const double " <> ToString[#[[1]]] <> " = " <>
2187     //     If[#[[2]] < 0.00001, "0.0", ToString[#[[2]]]] <> ";"] & /@ solution
2188     //
2189     // We've long known the following to be true:
2190     // - Small code blocks are cheap to optimize and so we should do it sooner rather
2191     //   than later.
2192     // - Large code blocks are expensive to optimize and so we should postpone doing so,
2193     //   and sometimes have a large enough threshold that we never optimize them.
2194     // - The difference in cost is not totally linear because (a) just invoking the
2195     //   DFG incurs some base cost and (b) for large code blocks there is enough slop
2196     //   in the correlation between instruction count and the actual compilation cost
2197     //   that for those large blocks, the instruction count should not have a strong
2198     //   influence on our threshold.
2199     //
2200     // I knew the goals but I didn't know how to achieve them; so I picked an interesting
2201     // example where the heuristics were right (code block in 3d-cube with instruction
2202     // count 320, which got compiled early as it should have been) and one where they were
2203     // totally wrong (code block in 3d-cube with instruction count 1268, which was expensive
2204     // to compile and didn't run often enough to warrant compilation in my opinion), and
2205     // then threw in additional data points that represented my own guess of what our
2206     // heuristics should do for some round-numbered examples.
2207     //
2208     // The expression to which I decided to fit the data arose because I started with an
2209     // affine function, and then did two things: put the linear part in an Abs to ensure
2210     // that the fit didn't end up choosing a negative value of c (which would result in
2211     // the function turning over and going negative for large x) and I threw in a Sqrt
2212     // term because Sqrt represents my intution that the function should be more sensitive
2213     // to small changes in small values of x, but less sensitive when x gets large.
2214
2215     // Note that the current fit essentially eliminates the linear portion of the
2216     // expression (c == 0.0).
2217     const double a = 0.061504;
2218     const double b = 1.02406;
2219     const double c = 0.0;
2220     const double d = 0.825914;
2221
2222     double instructionCount = this->instructionCount();
2223
2224     ASSERT(instructionCount); // Make sure this is called only after we have an instruction stream; otherwise it'll just return the value of d, which makes no sense.
2225
2226     double result = d + a * sqrt(instructionCount + b) + c * instructionCount;
2227
2228     result *= codeTypeThresholdMultiplier();
2229
2230     if (Options::verboseOSR()) {
2231         dataLog(
2232             *this, ": instruction count is ", instructionCount,
2233             ", scaling execution counter by ", result, " * ", codeTypeThresholdMultiplier(),
2234             "\n");
2235     }
2236     return result;
2237 }
2238
2239 static int32_t clipThreshold(double threshold)
2240 {
2241     if (threshold < 1.0)
2242         return 1;
2243
2244     if (threshold > static_cast<double>(std::numeric_limits<int32_t>::max()))
2245         return std::numeric_limits<int32_t>::max();
2246
2247     return static_cast<int32_t>(threshold);
2248 }
2249
2250 int32_t CodeBlock::adjustedCounterValue(int32_t desiredThreshold)
2251 {
2252     return clipThreshold(
2253         static_cast<double>(desiredThreshold) *
2254         optimizationThresholdScalingFactor() *
2255         (1 << reoptimizationRetryCounter()));
2256 }
2257
2258 bool CodeBlock::checkIfOptimizationThresholdReached()
2259 {
2260 #if ENABLE(DFG_JIT)
2261     if (DFG::Worklist* worklist = DFG::existingGlobalDFGWorklistOrNull()) {
2262         if (worklist->compilationState(DFG::CompilationKey(this, DFG::DFGMode))
2263             == DFG::Worklist::Compiled) {
2264             optimizeNextInvocation();
2265             return true;
2266         }
2267     }
2268 #endif
2269
2270     return m_jitExecuteCounter.checkIfThresholdCrossedAndSet(this);
2271 }
2272
2273 void CodeBlock::optimizeNextInvocation()
2274 {
2275     if (Options::verboseOSR())
2276         dataLog(*this, ": Optimizing next invocation.\n");
2277     m_jitExecuteCounter.setNewThreshold(0, this);
2278 }
2279
2280 void CodeBlock::dontOptimizeAnytimeSoon()
2281 {
2282     if (Options::verboseOSR())
2283         dataLog(*this, ": Not optimizing anytime soon.\n");
2284     m_jitExecuteCounter.deferIndefinitely();
2285 }
2286
2287 void CodeBlock::optimizeAfterWarmUp()
2288 {
2289     if (Options::verboseOSR())
2290         dataLog(*this, ": Optimizing after warm-up.\n");
2291 #if ENABLE(DFG_JIT)
2292     m_jitExecuteCounter.setNewThreshold(
2293         adjustedCounterValue(Options::thresholdForOptimizeAfterWarmUp()), this);
2294 #endif
2295 }
2296
2297 void CodeBlock::optimizeAfterLongWarmUp()
2298 {
2299     if (Options::verboseOSR())
2300         dataLog(*this, ": Optimizing after long warm-up.\n");
2301 #if ENABLE(DFG_JIT)
2302     m_jitExecuteCounter.setNewThreshold(
2303         adjustedCounterValue(Options::thresholdForOptimizeAfterLongWarmUp()), this);
2304 #endif
2305 }
2306
2307 void CodeBlock::optimizeSoon()
2308 {
2309     if (Options::verboseOSR())
2310         dataLog(*this, ": Optimizing soon.\n");
2311 #if ENABLE(DFG_JIT)
2312     m_jitExecuteCounter.setNewThreshold(
2313         adjustedCounterValue(Options::thresholdForOptimizeSoon()), this);
2314 #endif
2315 }
2316
2317 void CodeBlock::forceOptimizationSlowPathConcurrently()
2318 {
2319     if (Options::verboseOSR())
2320         dataLog(*this, ": Forcing slow path concurrently.\n");
2321     m_jitExecuteCounter.forceSlowPathConcurrently();
2322 }
2323
2324 #if ENABLE(DFG_JIT)
2325 void CodeBlock::setOptimizationThresholdBasedOnCompilationResult(CompilationResult result)
2326 {
2327     JITCode::JITType type = jitType();
2328     if (type != JITCode::BaselineJIT) {
2329         dataLog(*this, ": expected to have baseline code but have ", type, "\n");
2330         RELEASE_ASSERT_NOT_REACHED();
2331     }
2332
2333     CodeBlock* theReplacement = replacement();
2334     if ((result == CompilationSuccessful) != (theReplacement != this)) {
2335         dataLog(*this, ": we have result = ", result, " but ");
2336         if (theReplacement == this)
2337             dataLog("we are our own replacement.\n");
2338         else
2339             dataLog("our replacement is ", pointerDump(theReplacement), "\n");
2340         RELEASE_ASSERT_NOT_REACHED();
2341     }
2342
2343     switch (result) {
2344     case CompilationSuccessful:
2345         RELEASE_ASSERT(JITCode::isOptimizingJIT(replacement()->jitType()));
2346         optimizeNextInvocation();
2347         return;
2348     case CompilationFailed:
2349         dontOptimizeAnytimeSoon();
2350         return;
2351     case CompilationDeferred:
2352         // We'd like to do dontOptimizeAnytimeSoon() but we cannot because
2353         // forceOptimizationSlowPathConcurrently() is inherently racy. It won't
2354         // necessarily guarantee anything. So, we make sure that even if that
2355         // function ends up being a no-op, we still eventually retry and realize
2356         // that we have optimized code ready.
2357         optimizeAfterWarmUp();
2358         return;
2359     case CompilationInvalidated:
2360         // Retry with exponential backoff.
2361         countReoptimization();
2362         optimizeAfterWarmUp();
2363         return;
2364     }
2365
2366     dataLog("Unrecognized result: ", static_cast<int>(result), "\n");
2367     RELEASE_ASSERT_NOT_REACHED();
2368 }
2369
2370 #endif
2371
2372 uint32_t CodeBlock::adjustedExitCountThreshold(uint32_t desiredThreshold)
2373 {
2374     ASSERT(JITCode::isOptimizingJIT(jitType()));
2375     // Compute this the lame way so we don't saturate. This is called infrequently
2376     // enough that this loop won't hurt us.
2377     unsigned result = desiredThreshold;
2378     for (unsigned n = baselineVersion()->reoptimizationRetryCounter(); n--;) {
2379         unsigned newResult = result << 1;
2380         if (newResult < result)
2381             return std::numeric_limits<uint32_t>::max();
2382         result = newResult;
2383     }
2384     return result;
2385 }
2386
2387 uint32_t CodeBlock::exitCountThresholdForReoptimization()
2388 {
2389     return adjustedExitCountThreshold(Options::osrExitCountForReoptimization() * codeTypeThresholdMultiplier());
2390 }
2391
2392 uint32_t CodeBlock::exitCountThresholdForReoptimizationFromLoop()
2393 {
2394     return adjustedExitCountThreshold(Options::osrExitCountForReoptimizationFromLoop() * codeTypeThresholdMultiplier());
2395 }
2396
2397 bool CodeBlock::shouldReoptimizeNow()
2398 {
2399     return osrExitCounter() >= exitCountThresholdForReoptimization();
2400 }
2401
2402 bool CodeBlock::shouldReoptimizeFromLoopNow()
2403 {
2404     return osrExitCounter() >= exitCountThresholdForReoptimizationFromLoop();
2405 }
2406 #endif
2407
2408 ArrayProfile* CodeBlock::getArrayProfile(const ConcurrentJSLocker&, unsigned bytecodeOffset)
2409 {
2410     for (auto& m_arrayProfile : m_arrayProfiles) {
2411         if (m_arrayProfile.bytecodeOffset() == bytecodeOffset)
2412             return &m_arrayProfile;
2413     }
2414     return 0;
2415 }
2416
2417 ArrayProfile* CodeBlock::getArrayProfile(unsigned bytecodeOffset)
2418 {
2419     ConcurrentJSLocker locker(m_lock);
2420     return getArrayProfile(locker, bytecodeOffset);
2421 }
2422
2423 ArrayProfile* CodeBlock::addArrayProfile(const ConcurrentJSLocker&, unsigned bytecodeOffset)
2424 {
2425     m_arrayProfiles.append(ArrayProfile(bytecodeOffset));
2426     return &m_arrayProfiles.last();
2427 }
2428
2429 ArrayProfile* CodeBlock::addArrayProfile(unsigned bytecodeOffset)
2430 {
2431     ConcurrentJSLocker locker(m_lock);
2432     return addArrayProfile(locker, bytecodeOffset);
2433 }
2434
2435 ArrayProfile* CodeBlock::getOrAddArrayProfile(const ConcurrentJSLocker& locker, unsigned bytecodeOffset)
2436 {
2437     ArrayProfile* result = getArrayProfile(locker, bytecodeOffset);
2438     if (result)
2439         return result;
2440     return addArrayProfile(locker, bytecodeOffset);
2441 }
2442
2443 ArrayProfile* CodeBlock::getOrAddArrayProfile(unsigned bytecodeOffset)
2444 {
2445     ConcurrentJSLocker locker(m_lock);
2446     return getOrAddArrayProfile(locker, bytecodeOffset);
2447 }
2448
2449 #if ENABLE(DFG_JIT)
2450 Vector<CodeOrigin, 0, UnsafeVectorOverflow>& CodeBlock::codeOrigins()
2451 {
2452     return m_jitCode->dfgCommon()->codeOrigins;
2453 }
2454
2455 size_t CodeBlock::numberOfDFGIdentifiers() const
2456 {
2457     if (!JITCode::isOptimizingJIT(jitType()))
2458         return 0;
2459
2460     return m_jitCode->dfgCommon()->dfgIdentifiers.size();
2461 }
2462
2463 const Identifier& CodeBlock::identifier(int index) const
2464 {
2465     size_t unlinkedIdentifiers = m_unlinkedCode->numberOfIdentifiers();
2466     if (static_cast<unsigned>(index) < unlinkedIdentifiers)
2467         return m_unlinkedCode->identifier(index);
2468     ASSERT(JITCode::isOptimizingJIT(jitType()));
2469     return m_jitCode->dfgCommon()->dfgIdentifiers[index - unlinkedIdentifiers];
2470 }
2471 #endif // ENABLE(DFG_JIT)
2472
2473 void CodeBlock::updateAllPredictionsAndCountLiveness(unsigned& numberOfLiveNonArgumentValueProfiles, unsigned& numberOfSamplesInProfiles)
2474 {
2475     ConcurrentJSLocker locker(m_lock);
2476
2477     numberOfLiveNonArgumentValueProfiles = 0;
2478     numberOfSamplesInProfiles = 0; // If this divided by ValueProfile::numberOfBuckets equals numberOfValueProfiles() then value profiles are full.
2479     for (unsigned i = 0; i < totalNumberOfValueProfiles(); ++i) {
2480         ValueProfile* profile = getFromAllValueProfiles(i);
2481         unsigned numSamples = profile->totalNumberOfSamples();
2482         if (numSamples > ValueProfile::numberOfBuckets)
2483             numSamples = ValueProfile::numberOfBuckets; // We don't want profiles that are extremely hot to be given more weight.
2484         numberOfSamplesInProfiles += numSamples;
2485         if (profile->m_bytecodeOffset < 0) {
2486             profile->computeUpdatedPrediction(locker);
2487             continue;
2488         }
2489         if (profile->numberOfSamples() || profile->m_prediction != SpecNone)
2490             numberOfLiveNonArgumentValueProfiles++;
2491         profile->computeUpdatedPrediction(locker);
2492     }
2493
2494 #if ENABLE(DFG_JIT)
2495     m_lazyOperandValueProfiles.computeUpdatedPredictions(locker);
2496 #endif
2497 }
2498
2499 void CodeBlock::updateAllValueProfilePredictions()
2500 {
2501     unsigned ignoredValue1, ignoredValue2;
2502     updateAllPredictionsAndCountLiveness(ignoredValue1, ignoredValue2);
2503 }
2504
2505 void CodeBlock::updateAllArrayPredictions()
2506 {
2507     ConcurrentJSLocker locker(m_lock);
2508
2509     for (unsigned i = m_arrayProfiles.size(); i--;)
2510         m_arrayProfiles[i].computeUpdatedPrediction(locker, this);
2511
2512     // Don't count these either, for similar reasons.
2513     for (unsigned i = m_arrayAllocationProfiles.size(); i--;)
2514         m_arrayAllocationProfiles[i].updateIndexingType();
2515 }
2516
2517 void CodeBlock::updateAllPredictions()
2518 {
2519     updateAllValueProfilePredictions();
2520     updateAllArrayPredictions();
2521 }
2522
2523 bool CodeBlock::shouldOptimizeNow()
2524 {
2525     if (Options::verboseOSR())
2526         dataLog("Considering optimizing ", *this, "...\n");
2527
2528     if (m_optimizationDelayCounter >= Options::maximumOptimizationDelay())
2529         return true;
2530
2531     updateAllArrayPredictions();
2532
2533     unsigned numberOfLiveNonArgumentValueProfiles;
2534     unsigned numberOfSamplesInProfiles;
2535     updateAllPredictionsAndCountLiveness(numberOfLiveNonArgumentValueProfiles, numberOfSamplesInProfiles);
2536
2537     if (Options::verboseOSR()) {
2538         dataLogF(
2539             "Profile hotness: %lf (%u / %u), %lf (%u / %u)\n",
2540             (double)numberOfLiveNonArgumentValueProfiles / numberOfValueProfiles(),
2541             numberOfLiveNonArgumentValueProfiles, numberOfValueProfiles(),
2542             (double)numberOfSamplesInProfiles / ValueProfile::numberOfBuckets / numberOfValueProfiles(),
2543             numberOfSamplesInProfiles, ValueProfile::numberOfBuckets * numberOfValueProfiles());
2544     }
2545
2546     if ((!numberOfValueProfiles() || (double)numberOfLiveNonArgumentValueProfiles / numberOfValueProfiles() >= Options::desiredProfileLivenessRate())
2547         && (!totalNumberOfValueProfiles() || (double)numberOfSamplesInProfiles / ValueProfile::numberOfBuckets / totalNumberOfValueProfiles() >= Options::desiredProfileFullnessRate())
2548         && static_cast<unsigned>(m_optimizationDelayCounter) + 1 >= Options::minimumOptimizationDelay())
2549         return true;
2550
2551     ASSERT(m_optimizationDelayCounter < std::numeric_limits<uint8_t>::max());
2552     m_optimizationDelayCounter++;
2553     optimizeAfterWarmUp();
2554     return false;
2555 }
2556
2557 #if ENABLE(DFG_JIT)
2558 void CodeBlock::tallyFrequentExitSites()
2559 {
2560     ASSERT(JITCode::isOptimizingJIT(jitType()));
2561     ASSERT(alternative()->jitType() == JITCode::BaselineJIT);
2562
2563     CodeBlock* profiledBlock = alternative();
2564
2565     switch (jitType()) {
2566     case JITCode::DFGJIT: {
2567         DFG::JITCode* jitCode = m_jitCode->dfg();
2568         for (auto& exit : jitCode->osrExit)
2569             exit.considerAddingAsFrequentExitSite(profiledBlock);
2570         break;
2571     }
2572
2573 #if ENABLE(FTL_JIT)
2574     case JITCode::FTLJIT: {
2575         // There is no easy way to avoid duplicating this code since the FTL::JITCode::osrExit
2576         // vector contains a totally different type, that just so happens to behave like
2577         // DFG::JITCode::osrExit.
2578         FTL::JITCode* jitCode = m_jitCode->ftl();
2579         for (unsigned i = 0; i < jitCode->osrExit.size(); ++i) {
2580             FTL::OSRExit& exit = jitCode->osrExit[i];
2581             exit.considerAddingAsFrequentExitSite(profiledBlock);
2582         }
2583         break;
2584     }
2585 #endif
2586
2587     default:
2588         RELEASE_ASSERT_NOT_REACHED();
2589         break;
2590     }
2591 }
2592 #endif // ENABLE(DFG_JIT)
2593
2594 #if ENABLE(VERBOSE_VALUE_PROFILE)
2595 void CodeBlock::dumpValueProfiles()
2596 {
2597     dataLog("ValueProfile for ", *this, ":\n");
2598     for (unsigned i = 0; i < totalNumberOfValueProfiles(); ++i) {
2599         ValueProfile* profile = getFromAllValueProfiles(i);
2600         if (profile->m_bytecodeOffset < 0) {
2601             ASSERT(profile->m_bytecodeOffset == -1);
2602             dataLogF("   arg = %u: ", i);
2603         } else
2604             dataLogF("   bc = %d: ", profile->m_bytecodeOffset);
2605         if (!profile->numberOfSamples() && profile->m_prediction == SpecNone) {
2606             dataLogF("<empty>\n");
2607             continue;
2608         }
2609         profile->dump(WTF::dataFile());
2610         dataLogF("\n");
2611     }
2612     dataLog("RareCaseProfile for ", *this, ":\n");
2613     for (unsigned i = 0; i < numberOfRareCaseProfiles(); ++i) {
2614         RareCaseProfile* profile = rareCaseProfile(i);
2615         dataLogF("   bc = %d: %u\n", profile->m_bytecodeOffset, profile->m_counter);
2616     }
2617 }
2618 #endif // ENABLE(VERBOSE_VALUE_PROFILE)
2619
2620 unsigned CodeBlock::frameRegisterCount()
2621 {
2622     switch (jitType()) {
2623     case JITCode::InterpreterThunk:
2624         return LLInt::frameRegisterCountFor(this);
2625
2626 #if ENABLE(JIT)
2627     case JITCode::BaselineJIT:
2628         return JIT::frameRegisterCountFor(this);
2629 #endif // ENABLE(JIT)
2630
2631 #if ENABLE(DFG_JIT)
2632     case JITCode::DFGJIT:
2633     case JITCode::FTLJIT:
2634         return jitCode()->dfgCommon()->frameRegisterCount;
2635 #endif // ENABLE(DFG_JIT)
2636
2637     default:
2638         RELEASE_ASSERT_NOT_REACHED();
2639         return 0;
2640     }
2641 }
2642
2643 int CodeBlock::stackPointerOffset()
2644 {
2645     return virtualRegisterForLocal(frameRegisterCount() - 1).offset();
2646 }
2647
2648 size_t CodeBlock::predictedMachineCodeSize()
2649 {
2650     // This will be called from CodeBlock::CodeBlock before either m_vm or the
2651     // instructions have been initialized. It's OK to return 0 because what will really
2652     // matter is the recomputation of this value when the slow path is triggered.
2653     if (!m_vm)
2654         return 0;
2655
2656     if (!*m_vm->machineCodeBytesPerBytecodeWordForBaselineJIT)
2657         return 0; // It's as good of a prediction as we'll get.
2658
2659     // Be conservative: return a size that will be an overestimation 84% of the time.
2660     double multiplier = m_vm->machineCodeBytesPerBytecodeWordForBaselineJIT->mean() +
2661         m_vm->machineCodeBytesPerBytecodeWordForBaselineJIT->standardDeviation();
2662
2663     // Be paranoid: silently reject bogus multipiers. Silently doing the "wrong" thing
2664     // here is OK, since this whole method is just a heuristic.
2665     if (multiplier < 0 || multiplier > 1000)
2666         return 0;
2667
2668     double doubleResult = multiplier * m_instructions.size();
2669
2670     // Be even more paranoid: silently reject values that won't fit into a size_t. If
2671     // the function is so huge that we can't even fit it into virtual memory then we
2672     // should probably have some other guards in place to prevent us from even getting
2673     // to this point.
2674     if (doubleResult > std::numeric_limits<size_t>::max())
2675         return 0;
2676
2677     return static_cast<size_t>(doubleResult);
2678 }
2679
2680 bool CodeBlock::usesOpcode(OpcodeID opcodeID)
2681 {
2682     Interpreter* interpreter = vm()->interpreter;
2683     Instruction* instructionsBegin = instructions().begin();
2684     unsigned instructionCount = instructions().size();
2685
2686     for (unsigned bytecodeOffset = 0; bytecodeOffset < instructionCount; ) {
2687         switch (interpreter->getOpcodeID(instructionsBegin[bytecodeOffset])) {
2688 #define DEFINE_OP(curOpcode, length)        \
2689         case curOpcode:                     \
2690             if (curOpcode == opcodeID)      \
2691                 return true;                \
2692             bytecodeOffset += length;       \
2693             break;
2694             FOR_EACH_OPCODE_ID(DEFINE_OP)
2695 #undef DEFINE_OP
2696         default:
2697             RELEASE_ASSERT_NOT_REACHED();
2698             break;
2699         }
2700     }
2701
2702     return false;
2703 }
2704
2705 String CodeBlock::nameForRegister(VirtualRegister virtualRegister)
2706 {
2707     for (auto& constantRegister : m_constantRegisters) {
2708         if (constantRegister.get().isEmpty())
2709             continue;
2710         if (SymbolTable* symbolTable = jsDynamicCast<SymbolTable*>(*vm(), constantRegister.get())) {
2711             ConcurrentJSLocker locker(symbolTable->m_lock);
2712             auto end = symbolTable->end(locker);
2713             for (auto ptr = symbolTable->begin(locker); ptr != end; ++ptr) {
2714                 if (ptr->value.varOffset() == VarOffset(virtualRegister)) {
2715                     // FIXME: This won't work from the compilation thread.
2716                     // https://bugs.webkit.org/show_bug.cgi?id=115300
2717                     return ptr->key.get();
2718                 }
2719             }
2720         }
2721     }
2722     if (virtualRegister == thisRegister())
2723         return ASCIILiteral("this");
2724     if (virtualRegister.isArgument())
2725         return String::format("arguments[%3d]", virtualRegister.toArgument());
2726
2727     return "";
2728 }
2729
2730 ValueProfile* CodeBlock::valueProfileForBytecodeOffset(int bytecodeOffset)
2731 {
2732     OpcodeID opcodeID = m_vm->interpreter->getOpcodeID(instructions()[bytecodeOffset]);
2733     unsigned length = opcodeLength(opcodeID);
2734     return instructions()[bytecodeOffset + length - 1].u.profile;
2735 }
2736
2737 void CodeBlock::validate()
2738 {
2739     BytecodeLivenessAnalysis liveness(this); // Compute directly from scratch so it doesn't effect CodeBlock footprint.
2740
2741     FastBitVector liveAtHead = liveness.getLivenessInfoAtBytecodeOffset(0);
2742
2743     if (liveAtHead.numBits() != static_cast<size_t>(m_numCalleeLocals)) {
2744         beginValidationDidFail();
2745         dataLog("    Wrong number of bits in result!\n");
2746         dataLog("    Result: ", liveAtHead, "\n");
2747         dataLog("    Bit count: ", liveAtHead.numBits(), "\n");
2748         endValidationDidFail();
2749     }
2750
2751     for (unsigned i = m_numCalleeLocals; i--;) {
2752         VirtualRegister reg = virtualRegisterForLocal(i);
2753
2754         if (liveAtHead[i]) {
2755             beginValidationDidFail();
2756             dataLog("    Variable ", reg, " is expected to be dead.\n");
2757             dataLog("    Result: ", liveAtHead, "\n");
2758             endValidationDidFail();
2759         }
2760     }
2761 }
2762
2763 void CodeBlock::beginValidationDidFail()
2764 {
2765     dataLog("Validation failure in ", *this, ":\n");
2766     dataLog("\n");
2767 }
2768
2769 void CodeBlock::endValidationDidFail()
2770 {
2771     dataLog("\n");
2772     dumpBytecode();
2773     dataLog("\n");
2774     dataLog("Validation failure.\n");
2775     RELEASE_ASSERT_NOT_REACHED();
2776 }
2777
2778 void CodeBlock::addBreakpoint(unsigned numBreakpoints)
2779 {
2780     m_numBreakpoints += numBreakpoints;
2781     ASSERT(m_numBreakpoints);
2782     if (JITCode::isOptimizingJIT(jitType()))
2783         jettison(Profiler::JettisonDueToDebuggerBreakpoint);
2784 }
2785
2786 void CodeBlock::setSteppingMode(CodeBlock::SteppingMode mode)
2787 {
2788     m_steppingMode = mode;
2789     if (mode == SteppingModeEnabled && JITCode::isOptimizingJIT(jitType()))
2790         jettison(Profiler::JettisonDueToDebuggerStepping);
2791 }
2792
2793 RareCaseProfile* CodeBlock::addRareCaseProfile(int bytecodeOffset)
2794 {
2795     m_rareCaseProfiles.append(RareCaseProfile(bytecodeOffset));
2796     return &m_rareCaseProfiles.last();
2797 }
2798
2799 RareCaseProfile* CodeBlock::rareCaseProfileForBytecodeOffset(int bytecodeOffset)
2800 {
2801     return tryBinarySearch<RareCaseProfile, int>(
2802         m_rareCaseProfiles, m_rareCaseProfiles.size(), bytecodeOffset,
2803         getRareCaseProfileBytecodeOffset);
2804 }
2805
2806 unsigned CodeBlock::rareCaseProfileCountForBytecodeOffset(int bytecodeOffset)
2807 {
2808     RareCaseProfile* profile = rareCaseProfileForBytecodeOffset(bytecodeOffset);
2809     if (profile)
2810         return profile->m_counter;
2811     return 0;
2812 }
2813
2814 ArithProfile* CodeBlock::arithProfileForBytecodeOffset(int bytecodeOffset)
2815 {
2816     return arithProfileForPC(instructions().begin() + bytecodeOffset);
2817 }
2818
2819 ArithProfile* CodeBlock::arithProfileForPC(Instruction* pc)
2820 {
2821     auto opcodeID = vm()->interpreter->getOpcodeID(pc[0]);
2822     switch (opcodeID) {
2823     case op_negate:
2824         return bitwise_cast<ArithProfile*>(&pc[3].u.operand);
2825     case op_bitor:
2826     case op_bitand:
2827     case op_bitxor:
2828     case op_add:
2829     case op_mul:
2830     case op_sub:
2831     case op_div:
2832         return bitwise_cast<ArithProfile*>(&pc[4].u.operand);
2833     default:
2834         break;
2835     }
2836
2837     return nullptr;
2838 }
2839
2840 bool CodeBlock::couldTakeSpecialFastCase(int bytecodeOffset)
2841 {
2842     if (!hasBaselineJITProfiling())
2843         return false;
2844     ArithProfile* profile = arithProfileForBytecodeOffset(bytecodeOffset);
2845     if (!profile)
2846         return false;
2847     return profile->tookSpecialFastPath();
2848 }
2849
2850 #if ENABLE(JIT)
2851 DFG::CapabilityLevel CodeBlock::capabilityLevel()
2852 {
2853     DFG::CapabilityLevel result = computeCapabilityLevel();
2854     m_capabilityLevelState = result;
2855     return result;
2856 }
2857 #endif
2858
2859 void CodeBlock::insertBasicBlockBoundariesForControlFlowProfiler(RefCountedArray<Instruction>& instructions)
2860 {
2861     if (!unlinkedCodeBlock()->hasOpProfileControlFlowBytecodeOffsets())
2862         return;
2863     const Vector<size_t>& bytecodeOffsets = unlinkedCodeBlock()->opProfileControlFlowBytecodeOffsets();
2864     for (size_t i = 0, offsetsLength = bytecodeOffsets.size(); i < offsetsLength; i++) {
2865         // Because op_profile_control_flow is emitted at the beginning of every basic block, finding
2866         // the next op_profile_control_flow will give us the text range of a single basic block.
2867         size_t startIdx = bytecodeOffsets[i];
2868         RELEASE_ASSERT(vm()->interpreter->getOpcodeID(instructions[startIdx]) == op_profile_control_flow);
2869         int basicBlockStartOffset = instructions[startIdx + 1].u.operand;
2870         int basicBlockEndOffset;
2871         if (i + 1 < offsetsLength) {
2872             size_t endIdx = bytecodeOffsets[i + 1];
2873             RELEASE_ASSERT(vm()->interpreter->getOpcodeID(instructions[endIdx]) == op_profile_control_flow);
2874             basicBlockEndOffset = instructions[endIdx + 1].u.operand - 1;
2875         } else {
2876             basicBlockEndOffset = m_sourceOffset + ownerScriptExecutable()->source().length() - 1; // Offset before the closing brace.
2877             basicBlockStartOffset = std::min(basicBlockStartOffset, basicBlockEndOffset); // Some start offsets may be at the closing brace, ensure it is the offset before.
2878         }
2879
2880         // The following check allows for the same textual JavaScript basic block to have its bytecode emitted more
2881         // than once and still play nice with the control flow profiler. When basicBlockStartOffset is larger than
2882         // basicBlockEndOffset, it indicates that the bytecode generator has emitted code for the same AST node
2883         // more than once (for example: ForInNode, Finally blocks in TryNode, etc). Though these are different
2884         // basic blocks at the bytecode level, they are generated from the same textual basic block in the JavaScript
2885         // program. The condition:
2886         // (basicBlockEndOffset < basicBlockStartOffset)
2887         // is encountered when op_profile_control_flow lies across the boundary of these duplicated bytecode basic
2888         // blocks and the textual offset goes from the end of the duplicated block back to the beginning. These
2889         // ranges are dummy ranges and are ignored. The duplicated bytecode basic blocks point to the same
2890         // internal data structure, so if any of them execute, it will record the same textual basic block in the
2891         // JavaScript program as executing.
2892         // At the bytecode level, this situation looks like:
2893         // j: op_profile_control_flow (from j->k, we have basicBlockEndOffset < basicBlockStartOffset)
2894         // ...
2895         // k: op_profile_control_flow (we want to skip over the j->k block and start fresh at offset k as the start of a new basic block k->m).
2896         // ...
2897         // m: op_profile_control_flow
2898         if (basicBlockEndOffset < basicBlockStartOffset) {
2899             RELEASE_ASSERT(i + 1 < offsetsLength); // We should never encounter dummy blocks at the end of a CodeBlock.
2900             instructions[startIdx + 1].u.basicBlockLocation = vm()->controlFlowProfiler()->dummyBasicBlock();
2901             continue;
2902         }
2903
2904         BasicBlockLocation* basicBlockLocation = vm()->controlFlowProfiler()->getBasicBlockLocation(ownerScriptExecutable()->sourceID(), basicBlockStartOffset, basicBlockEndOffset);
2905
2906         // Find all functions that are enclosed within the range: [basicBlockStartOffset, basicBlockEndOffset]
2907         // and insert these functions' start/end offsets as gaps in the current BasicBlockLocation.
2908         // This is necessary because in the original source text of a JavaScript program,
2909         // function literals form new basic blocks boundaries, but they aren't represented
2910         // inside the CodeBlock's instruction stream.
2911         auto insertFunctionGaps = [basicBlockLocation, basicBlockStartOffset, basicBlockEndOffset] (const WriteBarrier<FunctionExecutable>& functionExecutable) {
2912             const UnlinkedFunctionExecutable* executable = functionExecutable->unlinkedExecutable();
2913             int functionStart = executable->typeProfilingStartOffset();
2914             int functionEnd = executable->typeProfilingEndOffset();
2915             if (functionStart >= basicBlockStartOffset && functionEnd <= basicBlockEndOffset)
2916                 basicBlockLocation->insertGap(functionStart, functionEnd);
2917         };
2918
2919         for (const WriteBarrier<FunctionExecutable>& executable : m_functionDecls)
2920             insertFunctionGaps(executable);
2921         for (const WriteBarrier<FunctionExecutable>& executable : m_functionExprs)
2922             insertFunctionGaps(executable);
2923
2924         instructions[startIdx + 1].u.basicBlockLocation = basicBlockLocation;
2925     }
2926 }
2927
2928 #if ENABLE(JIT)
2929 void CodeBlock::setPCToCodeOriginMap(std::unique_ptr<PCToCodeOriginMap>&& map)
2930 {
2931     m_pcToCodeOriginMap = WTFMove(map);
2932 }
2933
2934 std::optional<CodeOrigin> CodeBlock::findPC(void* pc)
2935 {
2936     if (m_pcToCodeOriginMap) {
2937         if (std::optional<CodeOrigin> codeOrigin = m_pcToCodeOriginMap->findPC(pc))
2938             return codeOrigin;
2939     }
2940
2941     for (Bag<StructureStubInfo>::iterator iter = m_stubInfos.begin(); !!iter; ++iter) {
2942         StructureStubInfo* stub = *iter;
2943         if (stub->containsPC(pc))
2944             return std::optional<CodeOrigin>(stub->codeOrigin);
2945     }
2946
2947     if (std::optional<CodeOrigin> codeOrigin = m_jitCode->findPC(this, pc))
2948         return codeOrigin;
2949
2950     return std::nullopt;
2951 }
2952 #endif // ENABLE(JIT)
2953
2954 std::optional<unsigned> CodeBlock::bytecodeOffsetFromCallSiteIndex(CallSiteIndex callSiteIndex)
2955 {
2956     std::optional<unsigned> bytecodeOffset;
2957     JITCode::JITType jitType = this->jitType();
2958     if (jitType == JITCode::InterpreterThunk || jitType == JITCode::BaselineJIT) {
2959 #if USE(JSVALUE64)
2960         bytecodeOffset = callSiteIndex.bits();
2961 #else
2962         Instruction* instruction = bitwise_cast<Instruction*>(callSiteIndex.bits());
2963         bytecodeOffset = instruction - instructions().begin();
2964 #endif
2965     } else if (jitType == JITCode::DFGJIT || jitType == JITCode::FTLJIT) {
2966 #if ENABLE(DFG_JIT)
2967         RELEASE_ASSERT(canGetCodeOrigin(callSiteIndex));
2968         CodeOrigin origin = codeOrigin(callSiteIndex);
2969         bytecodeOffset = origin.bytecodeIndex;
2970 #else
2971         RELEASE_ASSERT_NOT_REACHED();
2972 #endif
2973     }
2974
2975     return bytecodeOffset;
2976 }
2977
2978 int32_t CodeBlock::thresholdForJIT(int32_t threshold)
2979 {
2980     switch (unlinkedCodeBlock()->didOptimize()) {
2981     case MixedTriState:
2982         return threshold;
2983     case FalseTriState:
2984         return threshold * 4;
2985     case TrueTriState:
2986         return threshold / 2;
2987     }
2988     ASSERT_NOT_REACHED();
2989     return threshold;
2990 }
2991
2992 void CodeBlock::jitAfterWarmUp()
2993 {
2994     m_llintExecuteCounter.setNewThreshold(thresholdForJIT(Options::thresholdForJITAfterWarmUp()), this);
2995 }
2996
2997 void CodeBlock::jitSoon()
2998 {
2999     m_llintExecuteCounter.setNewThreshold(thresholdForJIT(Options::thresholdForJITSoon()), this);
3000 }
3001
3002 bool CodeBlock::hasInstalledVMTrapBreakpoints() const
3003 {
3004 #if ENABLE(SIGNAL_BASED_VM_TRAPS)
3005
3006     // This function may be called from a signal handler. We need to be
3007     // careful to not call anything that is not signal handler safe, e.g.
3008     // we should not perturb the refCount of m_jitCode.
3009     if (!JITCode::isOptimizingJIT(jitType()))
3010         return false;
3011     return m_jitCode->dfgCommon()->hasInstalledVMTrapsBreakpoints();
3012 #else
3013     return false;
3014 #endif
3015 }
3016
3017 bool CodeBlock::installVMTrapBreakpoints()
3018 {
3019 #if ENABLE(SIGNAL_BASED_VM_TRAPS)
3020     // This function may be called from a signal handler. We need to be
3021     // careful to not call anything that is not signal handler safe, e.g.
3022     // we should not perturb the refCount of m_jitCode.
3023     if (!JITCode::isOptimizingJIT(jitType()))
3024         return false;
3025     m_jitCode->dfgCommon()->installVMTrapBreakpoints();
3026     return true;
3027 #else
3028     return false;
3029 #endif
3030 }
3031
3032 void CodeBlock::dumpMathICStats()
3033 {
3034 #if ENABLE(MATH_IC_STATS)
3035     double numAdds = 0.0;
3036     double totalAddSize = 0.0;
3037     double numMuls = 0.0;
3038     double totalMulSize = 0.0;
3039     double numNegs = 0.0;
3040     double totalNegSize = 0.0;
3041     double numSubs = 0.0;
3042     double totalSubSize = 0.0;
3043
3044     auto countICs = [&] (CodeBlock* codeBlock) {
3045         for (JITAddIC* addIC : codeBlock->m_addICs) {
3046             numAdds++;
3047             totalAddSize += addIC->codeSize();
3048         }
3049
3050         for (JITMulIC* mulIC : codeBlock->m_mulICs) {
3051             numMuls++;
3052             totalMulSize += mulIC->codeSize();
3053         }
3054
3055         for (JITNegIC* negIC : codeBlock->m_negICs) {
3056             numNegs++;
3057             totalNegSize += negIC->codeSize();
3058         }
3059
3060         for (JITSubIC* subIC : codeBlock->m_subICs) {
3061             numSubs++;
3062             totalSubSize += subIC->codeSize();
3063         }
3064
3065         return false;
3066     };
3067     heap()->forEachCodeBlock(countICs);
3068
3069     dataLog("Num Adds: ", numAdds, "\n");
3070     dataLog("Total Add size in bytes: ", totalAddSize, "\n");
3071     dataLog("Average Add size: ", totalAddSize / numAdds, "\n");
3072     dataLog("\n");
3073     dataLog("Num Muls: ", numMuls, "\n");
3074     dataLog("Total Mul size in bytes: ", totalMulSize, "\n");
3075     dataLog("Average Mul size: ", totalMulSize / numMuls, "\n");
3076     dataLog("\n");
3077     dataLog("Num Negs: ", numNegs, "\n");
3078     dataLog("Total Neg size in bytes: ", totalNegSize, "\n");
3079     dataLog("Average Neg size: ", totalNegSize / numNegs, "\n");
3080     dataLog("\n");
3081     dataLog("Num Subs: ", numSubs, "\n");
3082     dataLog("Total Sub size in bytes: ", totalSubSize, "\n");
3083     dataLog("Average Sub size: ", totalSubSize / numSubs, "\n");
3084
3085     dataLog("-----------------------\n");
3086 #endif
3087 }
3088
3089 BytecodeLivenessAnalysis& CodeBlock::livenessAnalysisSlow()
3090 {
3091     std::unique_ptr<BytecodeLivenessAnalysis> analysis = std::make_unique<BytecodeLivenessAnalysis>(this);
3092     {
3093         ConcurrentJSLocker locker(m_lock);
3094         if (!m_livenessAnalysis)
3095             m_livenessAnalysis = WTFMove(analysis);
3096         return *m_livenessAnalysis;
3097     }
3098 }
3099
3100
3101 } // namespace JSC