void* prepareOSREntry(ExecState* exec, CodeBlock* codeBlock, unsigned bytecodeIndex) { #if DFG_ENABLE(OSR_ENTRY) ASSERT(codeBlock->getJITType() == JITCode::DFGJIT); ASSERT(codeBlock->alternative()); ASSERT(codeBlock->alternative()->getJITType() == JITCode::BaselineJIT); ASSERT(!codeBlock->jitCodeMap()); ASSERT(codeBlock->numberOfDFGOSREntries()); #if ENABLE(JIT_VERBOSE_OSR) dataLog("OSR in %p(%p) from bc#%u\n", codeBlock, codeBlock->alternative(), bytecodeIndex); #endif JSGlobalData* globalData = &exec->globalData(); OSREntryData* entry = codeBlock->dfgOSREntryDataForBytecodeIndex(bytecodeIndex); ASSERT(entry->m_bytecodeIndex == bytecodeIndex); // The code below checks if it is safe to perform OSR entry. It may find // that it is unsafe to do so, for any number of reasons, which are documented // below. If the code decides not to OSR then it returns 0, and it's the caller's // responsibility to patch up the state in such a way as to ensure that it's // both safe and efficient to continue executing baseline code for now. This // should almost certainly include calling either codeBlock->optimizeAfterWarmUp() // or codeBlock->dontOptimizeAnytimeSoon(). // 1) Verify predictions. If the predictions are inconsistent with the actual // values, then OSR entry is not possible at this time. It's tempting to // assume that we could somehow avoid this case. We can certainly avoid it // for first-time loop OSR - that is, OSR into a CodeBlock that we have just // compiled. Then we are almost guaranteed that all of the predictions will // check out. It would be pretty easy to make that a hard guarantee. But // then there would still be the case where two call frames with the same // baseline CodeBlock are on the stack at the same time. The top one // triggers compilation and OSR. In that case, we may no longer have // accurate value profiles for the one deeper in the stack. Hence, when we // pop into the CodeBlock that is deeper on the stack, we might OSR and // realize that the predictions are wrong. Probably, in most cases, this is // just an anomaly in the sense that the older CodeBlock simply went off // into a less-likely path. So, the wisest course of action is to simply not // OSR at this time. for (size_t argument = 0; argument < entry->m_expectedValues.numberOfArguments(); ++argument) { if (argument >= exec->argumentCountIncludingThis()) { #if ENABLE(JIT_VERBOSE_OSR) dataLog(" OSR failed because argument %zu was not passed, expected ", argument); entry->m_expectedValues.argument(argument).dump(WTF::dataFile()); dataLog(".\n"); #endif return 0; } JSValue value; if (!argument) value = exec->hostThisValue(); else value = exec->argument(argument - 1); if (!entry->m_expectedValues.argument(argument).validate(value)) { #if ENABLE(JIT_VERBOSE_OSR) dataLog(" OSR failed because argument %zu is %s, expected ", argument, value.description()); entry->m_expectedValues.argument(argument).dump(WTF::dataFile()); dataLog(".\n"); #endif return 0; } } for (size_t local = 0; local < entry->m_expectedValues.numberOfLocals(); ++local) { if (entry->m_localsForcedDouble.get(local)) { if (!exec->registers()[local].jsValue().isNumber()) { #if ENABLE(JIT_VERBOSE_OSR) dataLog(" OSR failed because variable %zu is %s, expected number.\n", local, exec->registers()[local].jsValue().description()); #endif return 0; } continue; } if (!entry->m_expectedValues.local(local).validate(exec->registers()[local].jsValue())) { #if ENABLE(JIT_VERBOSE_OSR) dataLog(" OSR failed because variable %zu is %s, expected ", local, exec->registers()[local].jsValue().description()); entry->m_expectedValues.local(local).dump(WTF::dataFile()); dataLog(".\n"); #endif return 0; } } // 2) Check the stack height. The DFG JIT may require a taller stack than the // baseline JIT, in some cases. If we can't grow the stack, then don't do // OSR right now. That's the only option we have unless we want basic block // boundaries to start throwing RangeErrors. Although that would be possible, // it seems silly: you'd be diverting the program to error handling when it // would have otherwise just kept running albeit less quickly. if (!globalData->interpreter->registerFile().grow(&exec->registers()[codeBlock->m_numCalleeRegisters])) { #if ENABLE(JIT_VERBOSE_OSR) dataLog(" OSR failed because stack growth failed.\n"); #endif return 0; } #if ENABLE(JIT_VERBOSE_OSR) dataLog(" OSR should succeed.\n"); #endif // 3) Perform data format conversions. for (size_t local = 0; local < entry->m_expectedValues.numberOfLocals(); ++local) { if (entry->m_localsForcedDouble.get(local)) *bitwise_cast<double*>(exec->registers() + local) = exec->registers()[local].jsValue().asNumber(); } // 4) Fix the call frame. exec->setCodeBlock(codeBlock); // 5) Find and return the destination machine code address. void* result = codeBlock->getJITCode().executableAddressAtOffset(entry->m_machineCodeOffset); #if ENABLE(JIT_VERBOSE_OSR) dataLog(" OSR returning machine code address %p.\n", result); #endif return result; #else // DFG_ENABLE(OSR_ENTRY) UNUSED_PARAM(exec); UNUSED_PARAM(codeBlock); UNUSED_PARAM(bytecodeIndex); return 0; #endif }
void Graph::dump(const char* prefix, NodeIndex nodeIndex) { Node& node = at(nodeIndex); NodeType op = node.op(); unsigned refCount = node.refCount(); bool skipped = !refCount; bool mustGenerate = node.mustGenerate(); if (mustGenerate) --refCount; dataLog("%s", prefix); printNodeWhiteSpace(node); // Example/explanation of dataflow dump output // // 14: <!2:7> GetByVal(@3, @13) // ^1 ^2 ^3 ^4 ^5 // // (1) The nodeIndex of this operation. // (2) The reference count. The number printed is the 'real' count, // not including the 'mustGenerate' ref. If the node is // 'mustGenerate' then the count it prefixed with '!'. // (3) The virtual register slot assigned to this node. // (4) The name of the operation. // (5) The arguments to the operation. The may be of the form: // @# - a NodeIndex referencing a prior node in the graph. // arg# - an argument number. // $# - the index in the CodeBlock of a constant { for numeric constants the value is displayed | for integers, in both decimal and hex }. // id# - the index in the CodeBlock of an identifier { if codeBlock is passed to dump(), the string representation is displayed }. // var# - the index of a var on the global object, used by GetGlobalVar/PutGlobalVar operations. dataLog("% 4d:%s<%c%u:", (int)nodeIndex, skipped ? " skipped " : " ", mustGenerate ? '!' : ' ', refCount); if (node.hasResult() && !skipped && node.hasVirtualRegister()) dataLog("%u", node.virtualRegister()); else dataLog("-"); dataLog(">\t%s(", opName(op)); bool hasPrinted = false; if (node.flags() & NodeHasVarArgs) { for (unsigned childIdx = node.firstChild(); childIdx < node.firstChild() + node.numChildren(); childIdx++) { if (hasPrinted) dataLog(", "); else hasPrinted = true; dataLog("%s@%u%s", useKindToString(m_varArgChildren[childIdx].useKind()), m_varArgChildren[childIdx].index(), speculationToAbbreviatedString( at(m_varArgChildren[childIdx]).prediction())); } } else { if (!!node.child1()) { dataLog("%s@%u%s", useKindToString(node.child1().useKind()), node.child1().index(), speculationToAbbreviatedString(at(node.child1()).prediction())); } if (!!node.child2()) { dataLog(", %s@%u%s", useKindToString(node.child2().useKind()), node.child2().index(), speculationToAbbreviatedString(at(node.child2()).prediction())); } if (!!node.child3()) { dataLog(", %s@%u%s", useKindToString(node.child3().useKind()), node.child3().index(), speculationToAbbreviatedString(at(node.child3()).prediction())); } hasPrinted = !!node.child1(); } if (strlen(nodeFlagsAsString(node.flags()))) { dataLog("%s%s", hasPrinted ? ", " : "", nodeFlagsAsString(node.flags())); hasPrinted = true; } if (node.hasArrayMode()) { dataLog("%s%s", hasPrinted ? ", " : "", modeToString(node.arrayMode())); hasPrinted = true; } if (node.hasVarNumber()) { dataLog("%svar%u", hasPrinted ? ", " : "", node.varNumber()); hasPrinted = true; } if (node.hasRegisterPointer()) { dataLog( "%sglobal%u(%p)", hasPrinted ? ", " : "", globalObjectFor(node.codeOrigin)->findRegisterIndex(node.registerPointer()), node.registerPointer()); hasPrinted = true; } if (node.hasIdentifier()) { dataLog("%sid%u{%s}", hasPrinted ? ", " : "", node.identifierNumber(), m_codeBlock->identifier(node.identifierNumber()).ustring().utf8().data()); hasPrinted = true; } if (node.hasStructureSet()) { for (size_t i = 0; i < node.structureSet().size(); ++i) { dataLog("%sstruct(%p)", hasPrinted ? ", " : "", node.structureSet()[i]); hasPrinted = true; } } if (node.hasStructure()) { dataLog("%sstruct(%p)", hasPrinted ? ", " : "", node.structure()); hasPrinted = true; } if (node.hasStructureTransitionData()) { dataLog("%sstruct(%p -> %p)", hasPrinted ? ", " : "", node.structureTransitionData().previousStructure, node.structureTransitionData().newStructure); hasPrinted = true; } if (node.hasStorageAccessData()) { StorageAccessData& storageAccessData = m_storageAccessData[node.storageAccessDataIndex()]; dataLog("%sid%u{%s}", hasPrinted ? ", " : "", storageAccessData.identifierNumber, m_codeBlock->identifier(storageAccessData.identifierNumber).ustring().utf8().data()); dataLog(", %lu", static_cast<unsigned long>(storageAccessData.offset)); hasPrinted = true; } ASSERT(node.hasVariableAccessData() == node.hasLocal()); if (node.hasVariableAccessData()) { VariableAccessData* variableAccessData = node.variableAccessData(); int operand = variableAccessData->operand(); if (operandIsArgument(operand)) dataLog("%sarg%u(%s)", hasPrinted ? ", " : "", operandToArgument(operand), nameOfVariableAccessData(variableAccessData)); else dataLog("%sr%u(%s)", hasPrinted ? ", " : "", operand, nameOfVariableAccessData(variableAccessData)); hasPrinted = true; } if (node.hasConstantBuffer()) { if (hasPrinted) dataLog(", "); dataLog("%u:[", node.startConstant()); for (unsigned i = 0; i < node.numConstants(); ++i) { if (i) dataLog(", "); dataLog("%s", m_codeBlock->constantBuffer(node.startConstant())[i].description()); } dataLog("]"); hasPrinted = true; } if (op == JSConstant) { dataLog("%s$%u", hasPrinted ? ", " : "", node.constantNumber()); JSValue value = valueOfJSConstant(nodeIndex); dataLog(" = %s", value.description()); hasPrinted = true; } if (op == WeakJSConstant) { dataLog("%s%p", hasPrinted ? ", " : "", node.weakConstant()); hasPrinted = true; } if (node.isBranch() || node.isJump()) { dataLog("%sT:#%u", hasPrinted ? ", " : "", node.takenBlockIndex()); hasPrinted = true; } if (node.isBranch()) { dataLog("%sF:#%u", hasPrinted ? ", " : "", node.notTakenBlockIndex()); hasPrinted = true; } dataLog("%sbc#%u", hasPrinted ? ", " : "", node.codeOrigin.bytecodeIndex); hasPrinted = true; (void)hasPrinted; dataLog(")"); if (!skipped) { if (node.hasVariableAccessData()) dataLog(" predicting %s%s", speculationToString(node.variableAccessData()->prediction()), node.variableAccessData()->shouldUseDoubleFormat() ? ", forcing double" : ""); else if (node.hasHeapPrediction()) dataLog(" predicting %s", speculationToString(node.getHeapPrediction())); } dataLog("\n"); }