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-rw-r--r--Source/JavaScriptCore/dfg/DFGOSREntry.cpp272
1 files changed, 218 insertions, 54 deletions
diff --git a/Source/JavaScriptCore/dfg/DFGOSREntry.cpp b/Source/JavaScriptCore/dfg/DFGOSREntry.cpp
index 9b75e70ab..80e688027 100644
--- a/Source/JavaScriptCore/dfg/DFGOSREntry.cpp
+++ b/Source/JavaScriptCore/dfg/DFGOSREntry.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2011 Apple Inc. All rights reserved.
+ * Copyright (C) 2011, 2013, 2014, 2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -30,31 +30,121 @@
#include "CallFrame.h"
#include "CodeBlock.h"
+#include "DFGJITCode.h"
#include "DFGNode.h"
#include "JIT.h"
-#include "Operations.h"
+#include "JSStackInlines.h"
+#include "JSCInlines.h"
+#include <wtf/CommaPrinter.h>
namespace JSC { namespace DFG {
+void OSREntryData::dumpInContext(PrintStream& out, DumpContext* context) const
+{
+ out.print("bc#", m_bytecodeIndex, ", machine code offset = ", m_machineCodeOffset);
+ 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_localsForcedMachineInt.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(virtualRegisterForArgument(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(ExecState* exec, CodeBlock* codeBlock, unsigned bytecodeIndex)
{
-#if DFG_ENABLE(OSR_ENTRY)
- ASSERT(codeBlock->getJITType() == JITCode::DFGJIT);
+ ASSERT(JITCode::isOptimizingJIT(codeBlock->jitType()));
ASSERT(codeBlock->alternative());
- ASSERT(codeBlock->alternative()->getJITType() == JITCode::BaselineJIT);
+ ASSERT(codeBlock->alternative()->jitType() == JITCode::BaselineJIT);
ASSERT(!codeBlock->jitCodeMap());
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLog("OSR in ", *codeBlock->alternative(), " -> ", *codeBlock, " from bc#", bytecodeIndex, "\n");
-#endif
+ if (!Options::useOSREntryToDFG())
+ return 0;
+
+ if (Options::verboseOSR()) {
+ dataLog(
+ "DFG OSR in ", *codeBlock->alternative(), " -> ", *codeBlock,
+ " from bc#", bytecodeIndex, "\n");
+ }
VM* vm = &exec->vm();
- OSREntryData* entry = codeBlock->dfgOSREntryDataForBytecodeIndex(bytecodeIndex);
+
+ sanitizeStackForVM(vm);
+
+ if (bytecodeIndex)
+ codeBlock->ownerScriptExecutable()->setDidTryToEnterInLoop(true);
+
+ if (codeBlock->jitType() != JITCode::DFGJIT) {
+ RELEASE_ASSERT(codeBlock->jitType() == JITCode::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.
+
+ if (Options::verboseOSR())
+ dataLog(" OSR failed because the target code block is not DFG.\n");
+ return 0;
+ }
+
+ JITCode* jitCode = codeBlock->jitCode()->dfg();
+ OSREntryData* entry = jitCode->osrEntryDataForBytecodeIndex(bytecodeIndex);
if (!entry) {
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLogF(" OSR failed because the entrypoint was optimized out.\n");
-#endif
+ if (Options::verboseOSR())
+ dataLogF(" OSR failed because the entrypoint was optimized out.\n");
return 0;
}
@@ -86,42 +176,62 @@ void* prepareOSREntry(ExecState* exec, CodeBlock* codeBlock, unsigned bytecodeIn
for (size_t argument = 0; argument < entry->m_expectedValues.numberOfArguments(); ++argument) {
if (argument >= exec->argumentCountIncludingThis()) {
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLogF(" OSR failed because argument %zu was not passed, expected ", argument);
- entry->m_expectedValues.argument(argument).dump(WTF::dataFile());
- dataLogF(".\n");
-#endif
+ if (Options::verboseOSR()) {
+ dataLogF(" OSR failed because argument %zu was not passed, expected ", argument);
+ entry->m_expectedValues.argument(argument).dump(WTF::dataFile());
+ dataLogF(".\n");
+ }
return 0;
}
JSValue value;
if (!argument)
- value = exec->hostThisValue();
+ value = exec->thisValue();
else
value = exec->argument(argument - 1);
if (!entry->m_expectedValues.argument(argument).validate(value)) {
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLog(" OSR failed because argument ", argument, " is ", value, ", expected ", entry->m_expectedValues.argument(argument), ".\n");
-#endif
+ if (Options::verboseOSR()) {
+ dataLog(
+ " OSR failed because argument ", argument, " is ", value,
+ ", expected ", entry->m_expectedValues.argument(argument), ".\n");
+ }
return 0;
}
}
for (size_t local = 0; local < entry->m_expectedValues.numberOfLocals(); ++local) {
+ int localOffset = virtualRegisterForLocal(local).offset();
if (entry->m_localsForcedDouble.get(local)) {
- if (!exec->registers()[local].jsValue().isNumber()) {
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLog(" OSR failed because variable ", local, " is ", exec->registers()[local].jsValue(), ", expected number.\n");
-#endif
+ if (!exec->registers()[localOffset].asanUnsafeJSValue().isNumber()) {
+ if (Options::verboseOSR()) {
+ dataLog(
+ " OSR failed because variable ", localOffset, " is ",
+ exec->registers()[localOffset].asanUnsafeJSValue(), ", expected number.\n");
+ }
return 0;
}
continue;
}
- if (!entry->m_expectedValues.local(local).isTop() && !entry->m_expectedValues.local(local).validate(exec->registers()[local].jsValue())) {
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLog(" OSR failed because variable ", local, " is ", exec->registers()[local].jsValue(), ", expected ", entry->m_expectedValues.local(local), ".\n");
-#endif
+ if (entry->m_localsForcedMachineInt.get(local)) {
+ if (!exec->registers()[localOffset].asanUnsafeJSValue().isMachineInt()) {
+ if (Options::verboseOSR()) {
+ dataLog(
+ " OSR failed because variable ", localOffset, " is ",
+ exec->registers()[localOffset].asanUnsafeJSValue(), ", expected ",
+ "machine int.\n");
+ }
+ return 0;
+ }
+ continue;
+ }
+ if (!entry->m_expectedValues.local(local).validate(exec->registers()[localOffset].asanUnsafeJSValue())) {
+ if (Options::verboseOSR()) {
+ dataLog(
+ " OSR failed because variable ", localOffset, " is ",
+ exec->registers()[localOffset].asanUnsafeJSValue(), ", expected ",
+ entry->m_expectedValues.local(local), ".\n");
+ }
return 0;
}
}
@@ -133,42 +243,96 @@ void* prepareOSREntry(ExecState* exec, CodeBlock* codeBlock, unsigned bytecodeIn
// it seems silly: you'd be diverting the program to error handling when it
// would have otherwise just kept running albeit less quickly.
- if (!vm->interpreter->stack().grow(&exec->registers()[codeBlock->m_numCalleeRegisters])) {
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLogF(" OSR failed because stack growth failed.\n");
-#endif
+ unsigned frameSizeForCheck = jitCode->common.requiredRegisterCountForExecutionAndExit();
+ if (!vm->interpreter->stack().ensureCapacityFor(&exec->registers()[virtualRegisterForLocal(frameSizeForCheck - 1).offset()])) {
+ if (Options::verboseOSR())
+ dataLogF(" OSR failed because stack growth failed.\n");
return 0;
}
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLogF(" OSR should succeed.\n");
-#endif
+ if (Options::verboseOSR())
+ dataLogF(" OSR should succeed.\n");
+
+ // 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) 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();
- }
+ // 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 + JSStack::CallFrameHeaderSize + maxFrameSize))->dataBuffer());
+
+ *bitwise_cast<size_t*>(scratch + 0) = frameSize;
- // 4) Fix the call frame.
+ void* targetPC = codeBlock->jitCode()->executableAddressAtOffset(entry->m_machineCodeOffset);
+ if (Options::verboseOSR())
+ dataLogF(" OSR using target PC %p.\n", targetPC);
+ RELEASE_ASSERT(targetPC);
+ *bitwise_cast<void**>(scratch + 1) = targetPC;
- exec->setCodeBlock(codeBlock);
+ Register* pivot = scratch + 2 + JSStack::CallFrameHeaderSize;
- // 5) Find and return the destination machine code address.
+ for (int index = -JSStack::CallFrameHeaderSize; 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) = exec->registers()[reg.offset()].asanUnsafeJSValue().asNumber();
+ continue;
+ }
+
+ if (entry->m_localsForcedMachineInt.get(reg.toLocal())) {
+ *bitwise_cast<int64_t*>(pivot + index) = exec->registers()[reg.offset()].asanUnsafeJSValue().asMachineInt() << JSValue::int52ShiftAmount;
+ continue;
+ }
+ }
+
+ pivot[index] = exec->registers()[reg.offset()].asanUnsafeJSValue();
+ }
- void* result = codeBlock->getJITCode().executableAddressAtOffset(entry->m_machineCodeOffset);
+ // 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];
-#if ENABLE(JIT_VERBOSE_OSR)
- dataLogF(" OSR returning machine code address %p.\n", result);
+ // 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
+ RegisterAtOffsetList* registerSaveLocations = codeBlock->calleeSaveRegisters();
+ RegisterAtOffsetList* allCalleeSaves = vm->getAllCalleeSaveRegisterOffsets();
+ RegisterSet dontSaveRegisters = RegisterSet(RegisterSet::stackRegisters(), RegisterSet::allFPRs());
+
+ unsigned registerCount = registerSaveLocations->size();
+ for (unsigned i = 0; i < registerCount; i++) {
+ RegisterAtOffset currentEntry = registerSaveLocations->at(i);
+ if (dontSaveRegisters.get(currentEntry.reg()))
+ continue;
+ RegisterAtOffset* vmCalleeSavesEntry = allCalleeSaves->find(currentEntry.reg());
+
+ *(bitwise_cast<intptr_t*>(pivot - 1) - currentEntry.offsetAsIndex()) = vm->calleeSaveRegistersBuffer[vmCalleeSavesEntry->offsetAsIndex()];
+ }
#endif
- return result;
-#else // DFG_ENABLE(OSR_ENTRY)
- UNUSED_PARAM(exec);
- UNUSED_PARAM(codeBlock);
- UNUSED_PARAM(bytecodeIndex);
- return 0;
-#endif
+ // 7) Fix the call frame to have the right code block.
+
+ *bitwise_cast<CodeBlock**>(pivot - 1 - JSStack::CodeBlock) = codeBlock;
+
+ if (Options::verboseOSR())
+ dataLogF(" OSR returning data buffer %p.\n", scratch);
+ return scratch;
}
} } // namespace JSC::DFG
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