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/*
* Copyright (C) 2011 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.
*/
#ifndef DFGExitProfile_h
#define DFGExitProfile_h
#include <wtf/HashSet.h>
#include <wtf/OwnPtr.h>
#include <wtf/Vector.h>
namespace JSC { namespace DFG {
enum ExitKind {
ExitKindUnset,
BadType, // We exited because a type prediction was wrong.
BadCache, // We exited because an inline cache was wrong.
Overflow, // We exited because of overflow.
NegativeZero, // We exited because we encountered negative zero.
OutOfBounds, // We had an out-of-bounds access to an array.
InadequateCoverage, // We exited because we ended up in code that didn't have profiling coverage.
ArgumentsEscaped, // We exited because arguments escaped but we didn't expect them to.
Uncountable, // We exited for none of the above reasons, and we should not count it. Most uses of this should be viewed as a FIXME.
UncountableWatchpoint // We exited because of a watchpoint, which isn't counted because watchpoints do tracking themselves.
};
inline const char* exitKindToString(ExitKind kind)
{
switch (kind) {
case ExitKindUnset:
return "Unset";
case BadType:
return "BadType";
case BadCache:
return "BadCache";
case Overflow:
return "Overflow";
case NegativeZero:
return "NegativeZero";
case OutOfBounds:
return "OutOfBounds";
case InadequateCoverage:
return "InadequateCoverage";
case ArgumentsEscaped:
return "ArgumentsEscaped";
case Uncountable:
return "Uncountable";
case UncountableWatchpoint:
return "UncountableWatchpoint";
default:
return "Unknown";
}
}
inline bool exitKindIsCountable(ExitKind kind)
{
switch (kind) {
case ExitKindUnset:
ASSERT_NOT_REACHED();
case BadType:
case Uncountable:
case UncountableWatchpoint:
return false;
default:
return true;
}
}
class FrequentExitSite {
public:
FrequentExitSite()
: m_bytecodeOffset(0) // 0 = empty value
, m_kind(ExitKindUnset)
{
}
FrequentExitSite(WTF::HashTableDeletedValueType)
: m_bytecodeOffset(1) // 1 = deleted value
, m_kind(ExitKindUnset)
{
}
explicit FrequentExitSite(unsigned bytecodeOffset, ExitKind kind)
: m_bytecodeOffset(bytecodeOffset)
, m_kind(kind)
{
ASSERT(exitKindIsCountable(kind));
}
// Use this constructor if you wish for the exit site to be counted globally within its
// code block.
explicit FrequentExitSite(ExitKind kind)
: m_bytecodeOffset(0)
, m_kind(kind)
{
ASSERT(exitKindIsCountable(kind));
}
bool operator!() const
{
return m_kind == ExitKindUnset;
}
bool operator==(const FrequentExitSite& other) const
{
return m_bytecodeOffset == other.m_bytecodeOffset
&& m_kind == other.m_kind;
}
unsigned hash() const
{
return WTF::intHash(m_bytecodeOffset) + m_kind;
}
unsigned bytecodeOffset() const { return m_bytecodeOffset; }
ExitKind kind() const { return m_kind; }
bool isHashTableDeletedValue() const
{
return m_kind == ExitKindUnset && m_bytecodeOffset;
}
private:
unsigned m_bytecodeOffset;
ExitKind m_kind;
};
struct FrequentExitSiteHash {
static unsigned hash(const FrequentExitSite& key) { return key.hash(); }
static bool equal(const FrequentExitSite& a, const FrequentExitSite& b) { return a == b; }
static const bool safeToCompareToEmptyOrDeleted = true;
};
} } // namespace JSC::DFG
namespace WTF {
template<typename T> struct DefaultHash;
template<> struct DefaultHash<JSC::DFG::FrequentExitSite> {
typedef JSC::DFG::FrequentExitSiteHash Hash;
};
template<typename T> struct HashTraits;
template<> struct HashTraits<JSC::DFG::FrequentExitSite> : SimpleClassHashTraits<JSC::DFG::FrequentExitSite> { };
} // namespace WTF
namespace JSC { namespace DFG {
class QueryableExitProfile;
class ExitProfile {
public:
ExitProfile();
~ExitProfile();
// Add a new frequent exit site. Return true if this is a new one, or false
// if we already knew about it. This is an O(n) operation, because it errs
// on the side of keeping the data structure compact. Also, this will only
// be called a fixed number of times per recompilation. Recompilation is
// rare to begin with, and implies doing O(n) operations on the CodeBlock
// anyway.
bool add(const FrequentExitSite&);
private:
friend class QueryableExitProfile;
OwnPtr<Vector<FrequentExitSite> > m_frequentExitSites;
};
class QueryableExitProfile {
public:
explicit QueryableExitProfile(const ExitProfile&);
~QueryableExitProfile();
bool hasExitSite(const FrequentExitSite& site) const
{
return m_frequentExitSites.find(site) != m_frequentExitSites.end();
}
bool hasExitSite(ExitKind kind) const
{
return hasExitSite(FrequentExitSite(kind));
}
bool hasExitSite(unsigned bytecodeIndex, ExitKind kind) const
{
return hasExitSite(FrequentExitSite(bytecodeIndex, kind));
}
private:
HashSet<FrequentExitSite> m_frequentExitSites;
};
} } // namespace JSC::DFG
#endif // DFGExitProfile_h
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