| /* |
| * Copyright (C) 2011-2019 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "config.h" |
| #include "DFGOSREntry.h" |
| |
| #if ENABLE(DFG_JIT) |
| |
| #include "BytecodeStructs.h" |
| #include "CallFrame.h" |
| #include "CodeBlock.h" |
| #include "DFGJITCode.h" |
| #include "DFGNode.h" |
| #include "JSCJSValueInlines.h" |
| #include "RegisterAtOffsetList.h" |
| #include "VMInlines.h" |
| #include <wtf/CommaPrinter.h> |
| |
| namespace JSC { namespace DFG { |
| |
| void OSREntryData::dumpInContext(PrintStream& out, DumpContext* context) const |
| { |
| out.print(m_bytecodeIndex, ", machine code = ", RawPointer(m_machineCode.executableAddress())); |
| out.print(", stack rules = ["); |
| |
| auto printOperand = [&] (VirtualRegister reg) { |
| out.print(inContext(m_expectedValues.operand(reg), context), " ("); |
| VirtualRegister toReg; |
| bool overwritten = false; |
| for (OSREntryReshuffling reshuffling : m_reshufflings) { |
| if (reg == VirtualRegister(reshuffling.fromOffset)) { |
| toReg = VirtualRegister(reshuffling.toOffset); |
| break; |
| } |
| if (reg == VirtualRegister(reshuffling.toOffset)) |
| overwritten = true; |
| } |
| if (!overwritten && !toReg.isValid()) |
| toReg = reg; |
| if (toReg.isValid()) { |
| if (toReg.isLocal() && !m_machineStackUsed.get(toReg.toLocal())) |
| out.print("ignored"); |
| else |
| out.print("maps to ", toReg); |
| } else |
| out.print("overwritten"); |
| if (reg.isLocal() && m_localsForcedDouble.get(reg.toLocal())) |
| out.print(", forced double"); |
| if (reg.isLocal() && m_localsForcedAnyInt.get(reg.toLocal())) |
| out.print(", forced machine int"); |
| out.print(")"); |
| }; |
| |
| CommaPrinter comma; |
| for (size_t argumentIndex = m_expectedValues.numberOfArguments(); argumentIndex--;) { |
| out.print(comma, "arg", argumentIndex, ":"); |
| printOperand(virtualRegisterForArgumentIncludingThis(argumentIndex)); |
| } |
| for (size_t localIndex = 0; localIndex < m_expectedValues.numberOfLocals(); ++localIndex) { |
| out.print(comma, "loc", localIndex, ":"); |
| printOperand(virtualRegisterForLocal(localIndex)); |
| } |
| |
| out.print("], machine stack used = ", m_machineStackUsed); |
| } |
| |
| void OSREntryData::dump(PrintStream& out) const |
| { |
| dumpInContext(out, nullptr); |
| } |
| |
| SUPPRESS_ASAN |
| void* prepareOSREntry(VM& vm, CallFrame* callFrame, CodeBlock* codeBlock, BytecodeIndex bytecodeIndex) |
| { |
| ASSERT(JITCode::isOptimizingJIT(codeBlock->jitType())); |
| ASSERT(codeBlock->alternative()); |
| ASSERT(codeBlock->alternative()->jitType() == JITType::BaselineJIT); |
| ASSERT(!codeBlock->jitCodeMap()); |
| ASSERT(codeBlock->jitCode()->dfgCommon()->isStillValid); |
| |
| if (!Options::useOSREntryToDFG()) |
| return nullptr; |
| |
| dataLogLnIf(Options::verboseOSR(), |
| "DFG OSR in ", *codeBlock->alternative(), " -> ", *codeBlock, |
| " from ", bytecodeIndex); |
| |
| sanitizeStackForVM(vm); |
| |
| if (bytecodeIndex) |
| codeBlock->ownerExecutable()->setDidTryToEnterInLoop(true); |
| |
| if (codeBlock->jitType() != JITType::DFGJIT) { |
| RELEASE_ASSERT(codeBlock->jitType() == JITType::FTLJIT); |
| |
| // When will this happen? We could have: |
| // |
| // - An exit from the FTL JIT into the baseline JIT followed by an attempt |
| // to reenter. We're fine with allowing this to fail. If it happens |
| // enough we'll just reoptimize. It basically means that the OSR exit cost |
| // us dearly and so reoptimizing is the right thing to do. |
| // |
| // - We have recursive code with hot loops. Consider that foo has a hot loop |
| // that calls itself. We have two foo's on the stack, lets call them foo1 |
| // and foo2, with foo1 having called foo2 from foo's hot loop. foo2 gets |
| // optimized all the way into the FTL. Then it returns into foo1, and then |
| // foo1 wants to get optimized. It might reach this conclusion from its |
| // hot loop and attempt to OSR enter. And we'll tell it that it can't. It |
| // might be worth addressing this case, but I just think this case will |
| // be super rare. For now, if it does happen, it'll cause some compilation |
| // thrashing. |
| |
| dataLogLnIf(Options::verboseOSR(), " OSR failed because the target code block is not DFG."); |
| return nullptr; |
| } |
| |
| JITCode* jitCode = codeBlock->jitCode()->dfg(); |
| OSREntryData* entry = jitCode->osrEntryDataForBytecodeIndex(bytecodeIndex); |
| |
| if (!entry) { |
| dataLogLnIf(Options::verboseOSR(), " OSR failed because the entrypoint was optimized out."); |
| return nullptr; |
| } |
| |
| 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) { |
| JSValue value; |
| if (!argument) |
| value = callFrame->thisValue(); |
| else |
| value = callFrame->argument(argument - 1); |
| |
| if (!entry->m_expectedValues.argument(argument).validateOSREntryValue(value, FlushedJSValue)) { |
| dataLogLnIf(Options::verboseOSR(), |
| " OSR failed because argument ", argument, " is ", value, |
| ", expected ", entry->m_expectedValues.argument(argument)); |
| return nullptr; |
| } |
| } |
| |
| for (size_t local = 0; local < entry->m_expectedValues.numberOfLocals(); ++local) { |
| int localOffset = virtualRegisterForLocal(local).offset(); |
| JSValue value = callFrame->registers()[localOffset].asanUnsafeJSValue(); |
| FlushFormat format = FlushedJSValue; |
| |
| if (entry->m_localsForcedAnyInt.get(local)) { |
| if (!value.isAnyInt()) { |
| dataLogLnIf(Options::verboseOSR(), |
| " OSR failed because variable ", localOffset, " is ", |
| value, ", expected ", |
| "machine int."); |
| return nullptr; |
| } |
| value = jsDoubleNumber(value.asAnyInt()); |
| format = FlushedInt52; |
| } |
| |
| if (entry->m_localsForcedDouble.get(local)) { |
| if (!value.isNumber()) { |
| dataLogLnIf(Options::verboseOSR(), |
| " OSR failed because variable ", localOffset, " is ", |
| value, ", expected number."); |
| return nullptr; |
| } |
| value = jsDoubleNumber(value.asNumber()); |
| format = FlushedDouble; |
| } |
| |
| if (!entry->m_expectedValues.local(local).validateOSREntryValue(value, format)) { |
| dataLogLnIf(Options::verboseOSR(), |
| " OSR failed because variable ", VirtualRegister(localOffset), " is ", |
| value, ", expected ", |
| entry->m_expectedValues.local(local), "."); |
| return nullptr; |
| } |
| } |
| |
| // 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. |
| |
| unsigned frameSizeForCheck = jitCode->common.requiredRegisterCountForExecutionAndExit(); |
| if (UNLIKELY(!vm.ensureStackCapacityFor(&callFrame->registers()[virtualRegisterForLocal(frameSizeForCheck - 1).offset()]))) { |
| dataLogLnIf(Options::verboseOSR(), " OSR failed because stack growth failed."); |
| return nullptr; |
| } |
| |
| dataLogLnIf(Options::verboseOSR(), " OSR should succeed."); |
| |
| // At this point we're committed to entering. We will do some work to set things up, |
| // but we also rely on our caller recognizing that when we return a non-null pointer, |
| // that means that we're already past the point of no return and we must succeed at |
| // entering. |
| |
| // 3) Set up the data in the scratch buffer and perform data format conversions. |
| |
| unsigned frameSize = jitCode->common.frameRegisterCount; |
| unsigned baselineFrameSize = entry->m_expectedValues.numberOfLocals(); |
| unsigned maxFrameSize = std::max(frameSize, baselineFrameSize); |
| |
| Register* scratch = bitwise_cast<Register*>(vm.scratchBufferForSize(sizeof(Register) * (2 + CallFrame::headerSizeInRegisters + maxFrameSize))->dataBuffer()); |
| |
| *bitwise_cast<size_t*>(scratch + 0) = frameSize; |
| |
| void* targetPC = entry->m_machineCode.executableAddress(); |
| RELEASE_ASSERT(codeBlock->jitCode()->contains(entry->m_machineCode.untaggedExecutableAddress())); |
| dataLogLnIf(Options::verboseOSR(), " OSR using target PC ", RawPointer(targetPC)); |
| RELEASE_ASSERT(targetPC); |
| *bitwise_cast<void**>(scratch + 1) = tagCodePtrWithStackPointerForJITCall(untagCodePtr<OSREntryPtrTag>(targetPC), callFrame); |
| |
| Register* pivot = scratch + 2 + CallFrame::headerSizeInRegisters; |
| |
| for (int index = -CallFrame::headerSizeInRegisters; index < static_cast<int>(baselineFrameSize); ++index) { |
| VirtualRegister reg(-1 - index); |
| |
| if (reg.isLocal()) { |
| if (entry->m_localsForcedDouble.get(reg.toLocal())) { |
| *bitwise_cast<double*>(pivot + index) = callFrame->registers()[reg.offset()].asanUnsafeJSValue().asNumber(); |
| continue; |
| } |
| |
| if (entry->m_localsForcedAnyInt.get(reg.toLocal())) { |
| *bitwise_cast<int64_t*>(pivot + index) = callFrame->registers()[reg.offset()].asanUnsafeJSValue().asAnyInt() << JSValue::int52ShiftAmount; |
| continue; |
| } |
| } |
| |
| pivot[index] = callFrame->registers()[reg.offset()].asanUnsafeJSValue(); |
| } |
| |
| // 4) Reshuffle those registers that need reshuffling. |
| Vector<JSValue> temporaryLocals(entry->m_reshufflings.size()); |
| for (unsigned i = entry->m_reshufflings.size(); i--;) |
| temporaryLocals[i] = pivot[VirtualRegister(entry->m_reshufflings[i].fromOffset).toLocal()].asanUnsafeJSValue(); |
| for (unsigned i = entry->m_reshufflings.size(); i--;) |
| pivot[VirtualRegister(entry->m_reshufflings[i].toOffset).toLocal()] = temporaryLocals[i]; |
| |
| // 5) Clear those parts of the call frame that the DFG ain't using. This helps GC on |
| // some programs by eliminating some stale pointer pathologies. |
| for (unsigned i = frameSize; i--;) { |
| if (entry->m_machineStackUsed.get(i)) |
| continue; |
| pivot[i] = JSValue(); |
| } |
| |
| // 6) Copy our callee saves to buffer. |
| #if NUMBER_OF_CALLEE_SAVES_REGISTERS > 0 |
| const RegisterAtOffsetList* registerSaveLocations = codeBlock->calleeSaveRegisters(); |
| RegisterAtOffsetList* allCalleeSaves = RegisterSet::vmCalleeSaveRegisterOffsets(); |
| RegisterSet dontSaveRegisters = RegisterSet(RegisterSet::stackRegisters(), RegisterSet::allFPRs()); |
| |
| unsigned registerCount = registerSaveLocations->size(); |
| VMEntryRecord* record = vmEntryRecord(vm.topEntryFrame); |
| for (unsigned i = 0; i < registerCount; i++) { |
| RegisterAtOffset currentEntry = registerSaveLocations->at(i); |
| if (dontSaveRegisters.get(currentEntry.reg())) |
| continue; |
| RegisterAtOffset* calleeSavesEntry = allCalleeSaves->find(currentEntry.reg()); |
| |
| if constexpr (CallerFrameAndPC::sizeInRegisters == 2) |
| *(bitwise_cast<intptr_t*>(pivot - 1) - currentEntry.offsetAsIndex()) = record->calleeSaveRegistersBuffer[calleeSavesEntry->offsetAsIndex()]; |
| else { |
| // We need to adjust 4-bytes on 32-bits, otherwise we will clobber some parts of |
| // pivot[-1] when currentEntry.offsetAsIndex() returns -1. This region contains |
| // CallerFrameAndPC and if it is cloberred, we will have a corrupted stack. |
| // Also, we need to store callee-save registers swapped in pairs on scratch buffer, |
| // otherwise they will be swapped when copied to call frame during OSR Entry code. |
| // Here is how we would like to have the buffer configured: |
| // |
| // pivot[-4] = ArgumentCountIncludingThis |
| // pivot[-3] = Callee |
| // pivot[-2] = CodeBlock |
| // pivot[-1] = CallerFrameAndReturnPC |
| // pivot[0] = csr1/csr0 |
| // pivot[1] = csr3/csr2 |
| // ... |
| ASSERT(sizeof(intptr_t) == 4); |
| ASSERT(CallerFrameAndPC::sizeInRegisters == 1); |
| ASSERT(currentEntry.offsetAsIndex() < 0); |
| |
| int offsetAsIndex = currentEntry.offsetAsIndex(); |
| int properIndex = offsetAsIndex % 2 ? offsetAsIndex - 1 : offsetAsIndex + 1; |
| *(bitwise_cast<intptr_t*>(pivot - 1) + 1 - properIndex) = record->calleeSaveRegistersBuffer[calleeSavesEntry->offsetAsIndex()]; |
| } |
| } |
| #endif |
| |
| // 7) Fix the call frame to have the right code block. |
| |
| *bitwise_cast<CodeBlock**>(pivot - (CallFrameSlot::codeBlock + 1)) = codeBlock; |
| |
| dataLogLnIf(Options::verboseOSR(), " OSR returning data buffer ", RawPointer(scratch)); |
| return scratch; |
| } |
| |
| MacroAssemblerCodePtr<ExceptionHandlerPtrTag> prepareCatchOSREntry(VM& vm, CallFrame* callFrame, CodeBlock* baselineCodeBlock, CodeBlock* optimizedCodeBlock, BytecodeIndex bytecodeIndex) |
| { |
| ASSERT(optimizedCodeBlock->jitType() == JITType::DFGJIT || optimizedCodeBlock->jitType() == JITType::FTLJIT); |
| ASSERT(optimizedCodeBlock->jitCode()->dfgCommon()->isStillValid); |
| |
| if (!Options::useOSREntryToDFG() && optimizedCodeBlock->jitCode()->jitType() == JITType::DFGJIT) |
| return nullptr; |
| if (!Options::useOSREntryToFTL() && optimizedCodeBlock->jitCode()->jitType() == JITType::FTLJIT) |
| return nullptr; |
| |
| CommonData* dfgCommon = optimizedCodeBlock->jitCode()->dfgCommon(); |
| RELEASE_ASSERT(dfgCommon); |
| DFG::CatchEntrypointData* catchEntrypoint = dfgCommon->catchOSREntryDataForBytecodeIndex(bytecodeIndex); |
| if (!catchEntrypoint) { |
| // This can be null under some circumstances. The most common is that we didn't |
| // compile this op_catch as an entrypoint since it had never executed when starting |
| // the compilation. |
| return nullptr; |
| } |
| |
| // We're only allowed to OSR enter if we've proven we have compatible argument types. |
| for (unsigned argument = 0; argument < catchEntrypoint->argumentFormats.size(); ++argument) { |
| JSValue value = callFrame->uncheckedR(virtualRegisterForArgumentIncludingThis(argument)).jsValue(); |
| switch (catchEntrypoint->argumentFormats[argument]) { |
| case DFG::FlushedInt32: |
| if (!value.isInt32()) |
| return nullptr; |
| break; |
| case DFG::FlushedCell: |
| if (!value.isCell()) |
| return nullptr; |
| break; |
| case DFG::FlushedBoolean: |
| if (!value.isBoolean()) |
| return nullptr; |
| break; |
| case DFG::DeadFlush: |
| // This means the argument is not alive. Therefore, it's allowed to be any type. |
| break; |
| case DFG::FlushedJSValue: |
| // An argument is trivially a JSValue. |
| break; |
| default: |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| } |
| |
| unsigned frameSizeForCheck = dfgCommon->requiredRegisterCountForExecutionAndExit(); |
| if (UNLIKELY(!vm.ensureStackCapacityFor(&callFrame->registers()[virtualRegisterForLocal(frameSizeForCheck).offset()]))) |
| return nullptr; |
| |
| auto instruction = baselineCodeBlock->instructions().at(callFrame->bytecodeIndex()); |
| ASSERT(instruction->is<OpCatch>()); |
| ValueProfileAndVirtualRegisterBuffer* buffer = instruction->as<OpCatch>().metadata(baselineCodeBlock).m_buffer; |
| JSValue* dataBuffer = reinterpret_cast<JSValue*>(dfgCommon->catchOSREntryBuffer->dataBuffer()); |
| unsigned index = 0; |
| buffer->forEach([&] (ValueProfileAndVirtualRegister& profile) { |
| if (!VirtualRegister(profile.m_operand).isLocal()) |
| return; |
| dataBuffer[index] = callFrame->uncheckedR(profile.m_operand).jsValue(); |
| ++index; |
| }); |
| |
| // The active length of catchOSREntryBuffer will be zeroed by ClearCatchLocals node. |
| dfgCommon->catchOSREntryBuffer->setActiveLength(sizeof(JSValue) * index); |
| return catchEntrypoint->machineCode; |
| } |
| |
| } } // namespace JSC::DFG |
| |
| #endif // ENABLE(DFG_JIT) |
