/*
- * Copyright (C) 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2012-2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
#include "config.h"
#include "CallLinkStatus.h"
+#include "CallLinkInfo.h"
#include "CodeBlock.h"
+#include "DFGJITCode.h"
#include "LLIntCallLinkInfo.h"
+#include "JSCInlines.h"
+#include <wtf/CommaPrinter.h>
+#include <wtf/ListDump.h>
namespace JSC {
-CallLinkStatus CallLinkStatus::computeFromLLInt(CodeBlock* profiledBlock, unsigned bytecodeIndex)
+static const bool verbose = false;
+
+CallLinkStatus::CallLinkStatus(JSValue value)
+ : m_couldTakeSlowPath(false)
+ , m_isProved(false)
+{
+ if (!value || !value.isCell()) {
+ m_couldTakeSlowPath = true;
+ return;
+ }
+
+ m_variants.append(CallVariant(value.asCell()));
+}
+
+CallLinkStatus CallLinkStatus::computeFromLLInt(const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, unsigned bytecodeIndex)
{
UNUSED_PARAM(profiledBlock);
UNUSED_PARAM(bytecodeIndex);
-#if ENABLE(LLINT)
+#if ENABLE(DFG_JIT)
+ if (profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadCell))) {
+ // We could force this to be a closure call, but instead we'll just assume that it
+ // takes slow path.
+ return takesSlowPath();
+ }
+#else
+ UNUSED_PARAM(locker);
+#endif
+
+ VM& vm = *profiledBlock->vm();
+
Instruction* instruction = profiledBlock->instructions().begin() + bytecodeIndex;
- LLIntCallLinkInfo* callLinkInfo = instruction[4].u.callLinkInfo;
+ OpcodeID op = vm.interpreter->getOpcodeID(instruction[0].u.opcode);
+ if (op != op_call && op != op_construct)
+ return CallLinkStatus();
+
+ LLIntCallLinkInfo* callLinkInfo = instruction[5].u.callLinkInfo;
+
+ return CallLinkStatus(callLinkInfo->lastSeenCallee.get());
+}
+
+CallLinkStatus CallLinkStatus::computeFor(
+ CodeBlock* profiledBlock, unsigned bytecodeIndex, const CallLinkInfoMap& map)
+{
+ ConcurrentJITLocker locker(profiledBlock->m_lock);
+
+ UNUSED_PARAM(profiledBlock);
+ UNUSED_PARAM(bytecodeIndex);
+ UNUSED_PARAM(map);
+#if ENABLE(DFG_JIT)
+ ExitSiteData exitSiteData = computeExitSiteData(locker, profiledBlock, bytecodeIndex);
+
+ CallLinkInfo* callLinkInfo = map.get(CodeOrigin(bytecodeIndex));
+ if (!callLinkInfo) {
+ if (exitSiteData.m_takesSlowPath)
+ return takesSlowPath();
+ return computeFromLLInt(locker, profiledBlock, bytecodeIndex);
+ }
- return CallLinkStatus(callLinkInfo->lastSeenCallee.get(), false);
+ return computeFor(locker, profiledBlock, *callLinkInfo, exitSiteData);
#else
- return CallLinkStatus(0, false);
+ return CallLinkStatus();
#endif
}
-CallLinkStatus CallLinkStatus::computeFor(CodeBlock* profiledBlock, unsigned bytecodeIndex)
+CallLinkStatus::ExitSiteData CallLinkStatus::computeExitSiteData(
+ const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, unsigned bytecodeIndex)
{
+ ExitSiteData exitSiteData;
+
+#if ENABLE(DFG_JIT)
+ exitSiteData.m_takesSlowPath =
+ profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadType))
+ || profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadExecutable));
+ exitSiteData.m_badFunction =
+ profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadCell));
+#else
+ UNUSED_PARAM(locker);
UNUSED_PARAM(profiledBlock);
UNUSED_PARAM(bytecodeIndex);
-#if ENABLE(JIT) && ENABLE(VALUE_PROFILER)
- if (!profiledBlock->numberOfCallLinkInfos())
- return computeFromLLInt(profiledBlock, bytecodeIndex);
+#endif
+
+ return exitSiteData;
+}
+
+#if ENABLE(JIT)
+CallLinkStatus CallLinkStatus::computeFor(
+ const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, CallLinkInfo& callLinkInfo)
+{
+ // We don't really need this, but anytime we have to debug this code, it becomes indispensable.
+ UNUSED_PARAM(profiledBlock);
+
+ CallLinkStatus result = computeFromCallLinkInfo(locker, callLinkInfo);
+ result.m_maxNumArguments = callLinkInfo.maxNumArguments();
+ return result;
+}
+
+CallLinkStatus CallLinkStatus::computeFromCallLinkInfo(
+ const ConcurrentJITLocker&, CallLinkInfo& callLinkInfo)
+{
+ if (callLinkInfo.clearedByGC())
+ return takesSlowPath();
- if (profiledBlock->couldTakeSlowCase(bytecodeIndex))
- return CallLinkStatus(0, true);
+ // Note that despite requiring that the locker is held, this code is racy with respect
+ // to the CallLinkInfo: it may get cleared while this code runs! This is because
+ // CallLinkInfo::unlink() may be called from a different CodeBlock than the one that owns
+ // the CallLinkInfo and currently we save space by not having CallLinkInfos know who owns
+ // them. So, there is no way for either the caller of CallLinkInfo::unlock() or unlock()
+ // itself to figure out which lock to lock.
+ //
+ // Fortunately, that doesn't matter. The only things we ask of CallLinkInfo - the slow
+ // path count, the stub, and the target - can all be asked racily. Stubs and targets can
+ // only be deleted at next GC, so if we load a non-null one, then it must contain data
+ // that is still marginally valid (i.e. the pointers ain't stale). This kind of raciness
+ // is probably OK for now.
- JSFunction* target = profiledBlock->getCallLinkInfo(bytecodeIndex).lastSeenCallee.get();
- if (!target)
- return computeFromLLInt(profiledBlock, bytecodeIndex);
+ // PolymorphicCallStubRoutine is a GCAwareJITStubRoutine, so if non-null, it will stay alive
+ // until next GC even if the CallLinkInfo is concurrently cleared. Also, the variants list is
+ // never mutated after the PolymorphicCallStubRoutine is instantiated. We have some conservative
+ // fencing in place to make sure that we see the variants list after construction.
+ if (PolymorphicCallStubRoutine* stub = callLinkInfo.stub()) {
+ WTF::loadLoadFence();
+
+ CallEdgeList edges = stub->edges();
+
+ // Now that we've loaded the edges list, there are no further concurrency concerns. We will
+ // just manipulate and prune this list to our liking - mostly removing entries that are too
+ // infrequent and ensuring that it's sorted in descending order of frequency.
+
+ RELEASE_ASSERT(edges.size());
+
+ std::sort(
+ edges.begin(), edges.end(),
+ [] (CallEdge a, CallEdge b) {
+ return a.count() > b.count();
+ });
+ RELEASE_ASSERT(edges.first().count() >= edges.last().count());
+
+ double totalCallsToKnown = 0;
+ double totalCallsToUnknown = callLinkInfo.slowPathCount();
+ CallVariantList variants;
+ for (size_t i = 0; i < edges.size(); ++i) {
+ CallEdge edge = edges[i];
+ // If the call is at the tail of the distribution, then we don't optimize it and we
+ // treat it as if it was a call to something unknown. We define the tail as being either
+ // a call that doesn't belong to the N most frequent callees (N =
+ // maxPolymorphicCallVariantsForInlining) or that has a total call count that is too
+ // small.
+ if (i >= Options::maxPolymorphicCallVariantsForInlining()
+ || edge.count() < Options::frequentCallThreshold())
+ totalCallsToUnknown += edge.count();
+ else {
+ totalCallsToKnown += edge.count();
+ variants.append(edge.callee());
+ }
+ }
+
+ // Bail if we didn't find any calls that qualified.
+ RELEASE_ASSERT(!!totalCallsToKnown == !!variants.size());
+ if (variants.isEmpty())
+ return takesSlowPath();
+
+ // We require that the distribution of callees is skewed towards a handful of common ones.
+ if (totalCallsToKnown / totalCallsToUnknown < Options::minimumCallToKnownRate())
+ return takesSlowPath();
+
+ RELEASE_ASSERT(totalCallsToKnown);
+ RELEASE_ASSERT(variants.size());
+
+ CallLinkStatus result;
+ result.m_variants = variants;
+ result.m_couldTakeSlowPath = !!totalCallsToUnknown;
+ return result;
+ }
- return CallLinkStatus(target, false);
-#else
- return CallLinkStatus(0, false);
+ CallLinkStatus result;
+
+ if (JSFunction* target = callLinkInfo.lastSeenCallee()) {
+ CallVariant variant(target);
+ if (callLinkInfo.hasSeenClosure())
+ variant = variant.despecifiedClosure();
+ result.m_variants.append(variant);
+ }
+
+ result.m_couldTakeSlowPath = !!callLinkInfo.slowPathCount();
+
+ return result;
+}
+
+CallLinkStatus CallLinkStatus::computeFor(
+ const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, CallLinkInfo& callLinkInfo,
+ ExitSiteData exitSiteData)
+{
+ CallLinkStatus result = computeFor(locker, profiledBlock, callLinkInfo);
+ if (exitSiteData.m_badFunction)
+ result.makeClosureCall();
+ if (exitSiteData.m_takesSlowPath)
+ result.m_couldTakeSlowPath = true;
+
+ return result;
+}
#endif
+
+void CallLinkStatus::computeDFGStatuses(
+ CodeBlock* dfgCodeBlock, CallLinkStatus::ContextMap& map)
+{
+#if ENABLE(DFG_JIT)
+ RELEASE_ASSERT(dfgCodeBlock->jitType() == JITCode::DFGJIT);
+ CodeBlock* baselineCodeBlock = dfgCodeBlock->alternative();
+ for (auto iter = dfgCodeBlock->callLinkInfosBegin(); !!iter; ++iter) {
+ CallLinkInfo& info = **iter;
+ CodeOrigin codeOrigin = info.codeOrigin();
+
+ // Check if we had already previously made a terrible mistake in the FTL for this
+ // code origin. Note that this is approximate because we could have a monovariant
+ // inline in the FTL that ended up failing. We should fix that at some point by
+ // having data structures to track the context of frequent exits. This is currently
+ // challenging because it would require creating a CodeOrigin-based database in
+ // baseline CodeBlocks, but those CodeBlocks don't really have a place to put the
+ // InlineCallFrames.
+ CodeBlock* currentBaseline =
+ baselineCodeBlockForOriginAndBaselineCodeBlock(codeOrigin, baselineCodeBlock);
+ ExitSiteData exitSiteData;
+ {
+ ConcurrentJITLocker locker(currentBaseline->m_lock);
+ exitSiteData = computeExitSiteData(
+ locker, currentBaseline, codeOrigin.bytecodeIndex);
+ }
+
+ {
+ ConcurrentJITLocker locker(dfgCodeBlock->m_lock);
+ map.add(info.codeOrigin(), computeFor(locker, dfgCodeBlock, info, exitSiteData));
+ }
+ }
+#else
+ UNUSED_PARAM(dfgCodeBlock);
+#endif // ENABLE(DFG_JIT)
+
+ if (verbose) {
+ dataLog("Context map:\n");
+ ContextMap::iterator iter = map.begin();
+ ContextMap::iterator end = map.end();
+ for (; iter != end; ++iter) {
+ dataLog(" ", iter->key, ":\n");
+ dataLog(" ", iter->value, "\n");
+ }
+ }
+}
+
+CallLinkStatus CallLinkStatus::computeFor(
+ CodeBlock* profiledBlock, CodeOrigin codeOrigin,
+ const CallLinkInfoMap& baselineMap, const CallLinkStatus::ContextMap& dfgMap)
+{
+ auto iter = dfgMap.find(codeOrigin);
+ if (iter != dfgMap.end())
+ return iter->value;
+
+ return computeFor(profiledBlock, codeOrigin.bytecodeIndex, baselineMap);
+}
+
+void CallLinkStatus::setProvenConstantCallee(CallVariant variant)
+{
+ m_variants = CallVariantList{ variant };
+ m_couldTakeSlowPath = false;
+ m_isProved = true;
+}
+
+bool CallLinkStatus::isClosureCall() const
+{
+ for (unsigned i = m_variants.size(); i--;) {
+ if (m_variants[i].isClosureCall())
+ return true;
+ }
+ return false;
+}
+
+void CallLinkStatus::makeClosureCall()
+{
+ m_variants = despecifiedVariantList(m_variants);
+}
+
+void CallLinkStatus::dump(PrintStream& out) const
+{
+ if (!isSet()) {
+ out.print("Not Set");
+ return;
+ }
+
+ CommaPrinter comma;
+
+ if (m_isProved)
+ out.print(comma, "Statically Proved");
+
+ if (m_couldTakeSlowPath)
+ out.print(comma, "Could Take Slow Path");
+
+ if (!m_variants.isEmpty())
+ out.print(comma, listDump(m_variants));
+
+ if (m_maxNumArguments)
+ out.print(comma, "maxNumArguments = ", m_maxNumArguments);
}
} // namespace JSC
projects / apple / javascriptcore.git / blobdiff