Ignore:
Timestamp:
Jan 29, 2015, 12:33:45 PM (11 years ago)
Author:
[email protected]
Message:

Polymorphic call inlining should be based on polymorphic call inline caching rather than logging
https://bugs.webkit.org/show_bug.cgi?id=140660

Reviewed by Geoffrey Garen.

When we first implemented polymorphic call inlining, we did the profiling based on a call
edge log. The idea was to store each call edge (a tuple of call site and callee) into a
global log that was processed lazily. Processing the log would give precise counts of call
edges, and could be used to drive well-informed inlining decisions - polymorphic or not.
This was a speed-up on throughput tests but a slow-down for latency tests. It was a net win
nonetheless.

Experience with this code shows three things. First, the call edge profiler is buggy and
complex. It would take work to fix the bugs. Second, the call edge profiler incurs lots of
overhead for latency code that we care deeply about. Third, it's not at all clear that
having call edge counts for every possible callee is any better than just having call edge
counts for the limited number of callees that an inline cache would catch.

So, this patch removes the call edge profiler and replaces it with a polymorphic call inline
cache. If we miss the basic call inline cache, we inflate the cache to be a jump to an
out-of-line stub that cases on the previously known callees. If that misses again, then we
rewrite that stub to include the new callee. We do this up to some number of callees. If we
hit the limit then we switch to using a plain virtual call.

Substantial speed-up on V8Spider; undoes the slow-down that the original call edge profiler
caused. Might be a SunSpider speed-up (below 1%), depending on hardware.

(JSC::CallEdge::count):
(JSC::CallEdge::CallEdge):

  • bytecode/CallEdgeProfile.cpp: Removed.
  • bytecode/CallEdgeProfile.h: Removed.
  • bytecode/CallEdgeProfileInlines.h: Removed.
  • bytecode/CallLinkInfo.cpp:

(JSC::CallLinkInfo::unlink):
(JSC::CallLinkInfo::visitWeak):

  • bytecode/CallLinkInfo.h:
  • bytecode/CallLinkStatus.cpp:

(JSC::CallLinkStatus::CallLinkStatus):
(JSC::CallLinkStatus::computeFor):
(JSC::CallLinkStatus::computeFromCallLinkInfo):
(JSC::CallLinkStatus::isClosureCall):
(JSC::CallLinkStatus::makeClosureCall):
(JSC::CallLinkStatus::dump):
(JSC::CallLinkStatus::computeFromCallEdgeProfile): Deleted.

  • bytecode/CallLinkStatus.h:

(JSC::CallLinkStatus::CallLinkStatus):
(JSC::CallLinkStatus::isSet):
(JSC::CallLinkStatus::variants):
(JSC::CallLinkStatus::size):
(JSC::CallLinkStatus::at):
(JSC::CallLinkStatus::operator[]):
(JSC::CallLinkStatus::canOptimize):
(JSC::CallLinkStatus::edges): Deleted.
(JSC::CallLinkStatus::canTrustCounts): Deleted.

  • bytecode/CallVariant.cpp:

(JSC::variantListWithVariant):
(JSC::despecifiedVariantList):

  • bytecode/CallVariant.h:
  • bytecode/CodeBlock.cpp:

(JSC::CodeBlock::~CodeBlock):
(JSC::CodeBlock::linkIncomingPolymorphicCall):
(JSC::CodeBlock::unlinkIncomingCalls):
(JSC::CodeBlock::noticeIncomingCall):

  • bytecode/CodeBlock.h:

(JSC::CodeBlock::isIncomingCallAlreadyLinked): Deleted.

  • dfg/DFGAbstractInterpreterInlines.h:

(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):

  • dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::addCallWithoutSettingResult):
(JSC::DFG::ByteCodeParser::handleCall):
(JSC::DFG::ByteCodeParser::handleInlining):

  • dfg/DFGClobberize.h:

(JSC::DFG::clobberize):

  • dfg/DFGConstantFoldingPhase.cpp:

(JSC::DFG::ConstantFoldingPhase::foldConstants):

  • dfg/DFGDoesGC.cpp:

(JSC::DFG::doesGC):

  • dfg/DFGDriver.cpp:

(JSC::DFG::compileImpl):

  • dfg/DFGFixupPhase.cpp:

(JSC::DFG::FixupPhase::fixupNode):

  • dfg/DFGNode.h:

(JSC::DFG::Node::hasHeapPrediction):

  • dfg/DFGNodeType.h:
  • dfg/DFGOperations.cpp:
  • dfg/DFGPredictionPropagationPhase.cpp:

(JSC::DFG::PredictionPropagationPhase::propagate):

  • dfg/DFGSafeToExecute.h:

(JSC::DFG::safeToExecute):

  • dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::SpeculativeJIT::emitCall):
(JSC::DFG::SpeculativeJIT::compile):

  • dfg/DFGSpeculativeJIT64.cpp:

(JSC::DFG::SpeculativeJIT::emitCall):
(JSC::DFG::SpeculativeJIT::compile):

  • dfg/DFGTierUpCheckInjectionPhase.cpp:

(JSC::DFG::TierUpCheckInjectionPhase::run):
(JSC::DFG::TierUpCheckInjectionPhase::removeFTLProfiling): Deleted.

  • ftl/FTLCapabilities.cpp:

(JSC::FTL::canCompile):

  • heap/Heap.cpp:

(JSC::Heap::collect):

  • jit/BinarySwitch.h:
  • jit/ClosureCallStubRoutine.cpp: Removed.
  • jit/ClosureCallStubRoutine.h: Removed.
  • jit/JITCall.cpp:

(JSC::JIT::compileOpCall):

  • jit/JITCall32_64.cpp:

(JSC::JIT::compileOpCall):

  • jit/JITOperations.cpp:
  • jit/JITOperations.h:

(JSC::operationLinkPolymorphicCallFor):
(JSC::operationLinkClosureCallFor): Deleted.

  • jit/JITStubRoutine.h:
  • jit/JITWriteBarrier.h:
  • jit/PolymorphicCallStubRoutine.cpp: Added.

(JSC::PolymorphicCallNode::~PolymorphicCallNode):
(JSC::PolymorphicCallNode::unlink):
(JSC::PolymorphicCallCase::dump):
(JSC::PolymorphicCallStubRoutine::PolymorphicCallStubRoutine):
(JSC::PolymorphicCallStubRoutine::~PolymorphicCallStubRoutine):
(JSC::PolymorphicCallStubRoutine::variants):
(JSC::PolymorphicCallStubRoutine::edges):
(JSC::PolymorphicCallStubRoutine::visitWeak):
(JSC::PolymorphicCallStubRoutine::markRequiredObjectsInternal):

  • jit/PolymorphicCallStubRoutine.h: Added.

(JSC::PolymorphicCallNode::PolymorphicCallNode):
(JSC::PolymorphicCallCase::PolymorphicCallCase):
(JSC::PolymorphicCallCase::variant):
(JSC::PolymorphicCallCase::codeBlock):

  • jit/Repatch.cpp:

(JSC::linkSlowFor):
(JSC::linkFor):
(JSC::revertCall):
(JSC::unlinkFor):
(JSC::linkVirtualFor):
(JSC::linkPolymorphicCall):
(JSC::linkClosureCall): Deleted.

  • jit/Repatch.h:
  • jit/ThunkGenerators.cpp:

(JSC::linkPolymorphicCallForThunkGenerator):
(JSC::linkPolymorphicCallThunkGenerator):
(JSC::linkPolymorphicCallThatPreservesRegsThunkGenerator):
(JSC::linkClosureCallForThunkGenerator): Deleted.
(JSC::linkClosureCallThunkGenerator): Deleted.
(JSC::linkClosureCallThatPreservesRegsThunkGenerator): Deleted.

  • jit/ThunkGenerators.h:

(JSC::linkPolymorphicCallThunkGeneratorFor):
(JSC::linkClosureCallThunkGeneratorFor): Deleted.

  • llint/LLIntSlowPaths.cpp:

(JSC::LLInt::jitCompileAndSetHeuristics):

  • runtime/Options.h:
  • runtime/VM.cpp:

(JSC::VM::prepareToDiscardCode):
(JSC::VM::ensureCallEdgeLog): Deleted.

  • runtime/VM.h:
File:
1 edited

Legend:

Unmodified
Added
Removed
  • trunk/Source/JavaScriptCore/bytecode/CallLinkStatus.h

    r173069 r179357  
    11/*
    2  * Copyright (C) 2012, 2013, 2014 Apple Inc. All rights reserved.
     2 * Copyright (C) 2012-2015 Apple Inc. All rights reserved.
    33 *
    44 * Redistribution and use in source and binary forms, with or without
     
    2828
    2929#include "CallLinkInfo.h"
     30#include "CallVariant.h"
    3031#include "CodeOrigin.h"
    3132#include "CodeSpecializationKind.h"
     
    4950        : m_couldTakeSlowPath(false)
    5051        , m_isProved(false)
    51         , m_canTrustCounts(false)
    5252    {
    5353    }
     
    6363   
    6464    CallLinkStatus(CallVariant variant)
    65         : m_edges(1, CallEdge(variant, 1))
     65        : m_variants(1, variant)
    6666        , m_couldTakeSlowPath(false)
    6767        , m_isProved(false)
    68         , m_canTrustCounts(false)
    6968    {
    7069    }
     
    110109        CodeBlock*, CodeOrigin, const CallLinkInfoMap&, const ContextMap&);
    111110   
    112     bool isSet() const { return !m_edges.isEmpty() || m_couldTakeSlowPath; }
     111    bool isSet() const { return !m_variants.isEmpty() || m_couldTakeSlowPath; }
    113112   
    114113    bool operator!() const { return !isSet(); }
     
    116115    bool couldTakeSlowPath() const { return m_couldTakeSlowPath; }
    117116   
    118     CallEdgeList edges() const { return m_edges; }
    119     unsigned size() const { return m_edges.size(); }
    120     CallEdge at(unsigned i) const { return m_edges[i]; }
    121     CallEdge operator[](unsigned i) const { return at(i); }
     117    CallVariantList variants() const { return m_variants; }
     118    unsigned size() const { return m_variants.size(); }
     119    CallVariant at(unsigned i) const { return m_variants[i]; }
     120    CallVariant operator[](unsigned i) const { return at(i); }
    122121    bool isProved() const { return m_isProved; }
    123     bool canOptimize() const { return !m_edges.isEmpty(); }
    124     bool canTrustCounts() const { return m_canTrustCounts; }
     122    bool canOptimize() const { return !m_variants.isEmpty(); }
    125123   
    126124    bool isClosureCall() const; // Returns true if any callee is a closure call.
     
    133131    static CallLinkStatus computeFromLLInt(const ConcurrentJITLocker&, CodeBlock*, unsigned bytecodeIndex);
    134132#if ENABLE(JIT)
    135     static CallLinkStatus computeFromCallEdgeProfile(CallEdgeProfile*);
    136133    static CallLinkStatus computeFromCallLinkInfo(
    137134        const ConcurrentJITLocker&, CallLinkInfo&);
    138135#endif
    139136   
    140     CallEdgeList m_edges;
     137    CallVariantList m_variants;
    141138    bool m_couldTakeSlowPath;
    142139    bool m_isProved;
    143     bool m_canTrustCounts;
    144140};
    145141
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