Modified: trunk/Source/_javascript_Core/runtime/SymbolTable.h (149233 => 149234)
--- trunk/Source/_javascript_Core/runtime/SymbolTable.h 2013-04-27 05:44:33 UTC (rev 149233)
+++ trunk/Source/_javascript_Core/runtime/SymbolTable.h 2013-04-27 06:28:59 UTC (rev 149234)
@@ -37,369 +37,369 @@
namespace JSC {
- class Watchpoint;
- class WatchpointSet;
+class Watchpoint;
+class WatchpointSet;
- struct SlowArgument {
- enum Status {
- Normal = 0,
- Captured = 1,
- Deleted = 2
- };
-
- SlowArgument()
- : status(Normal)
- , index(0)
- {
- }
-
- Status status;
- int index; // If status is 'Deleted', index is bogus.
+struct SlowArgument {
+ enum Status {
+ Normal = 0,
+ Captured = 1,
+ Deleted = 2
};
- static ALWAYS_INLINE int missingSymbolMarker() { return std::numeric_limits<int>::max(); }
+ SlowArgument()
+ : status(Normal)
+ , index(0)
+ {
+ }
- // The bit twiddling in this class assumes that every register index is a
- // reasonably small positive or negative number, and therefore has its high
- // four bits all set or all unset.
+ Status status;
+ int index; // If status is 'Deleted', index is bogus.
+};
- // In addition to implementing semantics-mandated variable attributes and
- // implementation-mandated variable indexing, this class also implements
- // watchpoints to be used for JIT optimizations. Because watchpoints are
- // meant to be relatively rare, this class optimizes heavily for the case
- // that they are not being used. To that end, this class uses the thin-fat
- // idiom: either it is thin, in which case it contains an in-place encoded
- // word that consists of attributes, the index, and a bit saying that it is
- // thin; or it is fat, in which case it contains a pointer to a malloc'd
- // data structure and a bit saying that it is fat. The malloc'd data
- // structure will be malloced a second time upon copy, to preserve the
- // property that in-place edits to SymbolTableEntry do not manifest in any
- // copies. However, the malloc'd FatEntry data structure contains a ref-
- // counted pointer to a shared WatchpointSet. Thus, in-place edits of the
- // WatchpointSet will manifest in all copies. Here's a picture:
- //
- // SymbolTableEntry --> FatEntry --> WatchpointSet
- //
- // If you make a copy of a SymbolTableEntry, you will have:
- //
- // original: SymbolTableEntry --> FatEntry --> WatchpointSet
- // copy: SymbolTableEntry --> FatEntry -----^
+static ALWAYS_INLINE int missingSymbolMarker() { return std::numeric_limits<int>::max(); }
- struct SymbolTableEntry {
- // Use the SymbolTableEntry::Fast class, either via implicit cast or by calling
- // getFast(), when you (1) only care about isNull(), getIndex(), and isReadOnly(),
- // and (2) you are in a hot path where you need to minimize the number of times
- // that you branch on isFat() when getting the bits().
- class Fast {
- public:
- Fast()
- : m_bits(SlimFlag)
- {
- }
-
- ALWAYS_INLINE Fast(const SymbolTableEntry& entry)
- : m_bits(entry.bits())
- {
- }
-
- bool isNull() const
- {
- return !(m_bits & ~SlimFlag);
- }
+// The bit twiddling in this class assumes that every register index is a
+// reasonably small positive or negative number, and therefore has its high
+// four bits all set or all unset.
- int getIndex() const
- {
- return static_cast<int>(m_bits >> FlagBits);
- }
-
- bool isReadOnly() const
- {
- return m_bits & ReadOnlyFlag;
- }
-
- unsigned getAttributes() const
- {
- unsigned attributes = 0;
- if (m_bits & ReadOnlyFlag)
- attributes |= ReadOnly;
- if (m_bits & DontEnumFlag)
- attributes |= DontEnum;
- return attributes;
- }
+// In addition to implementing semantics-mandated variable attributes and
+// implementation-mandated variable indexing, this class also implements
+// watchpoints to be used for JIT optimizations. Because watchpoints are
+// meant to be relatively rare, this class optimizes heavily for the case
+// that they are not being used. To that end, this class uses the thin-fat
+// idiom: either it is thin, in which case it contains an in-place encoded
+// word that consists of attributes, the index, and a bit saying that it is
+// thin; or it is fat, in which case it contains a pointer to a malloc'd
+// data structure and a bit saying that it is fat. The malloc'd data
+// structure will be malloced a second time upon copy, to preserve the
+// property that in-place edits to SymbolTableEntry do not manifest in any
+// copies. However, the malloc'd FatEntry data structure contains a ref-
+// counted pointer to a shared WatchpointSet. Thus, in-place edits of the
+// WatchpointSet will manifest in all copies. Here's a picture:
+//
+// SymbolTableEntry --> FatEntry --> WatchpointSet
+//
+// If you make a copy of a SymbolTableEntry, you will have:
+//
+// original: SymbolTableEntry --> FatEntry --> WatchpointSet
+// copy: SymbolTableEntry --> FatEntry -----^
- bool isFat() const
- {
- return !(m_bits & SlimFlag);
- }
-
- private:
- friend struct SymbolTableEntry;
- intptr_t m_bits;
- };
-
- SymbolTableEntry()
+struct SymbolTableEntry {
+ // Use the SymbolTableEntry::Fast class, either via implicit cast or by calling
+ // getFast(), when you (1) only care about isNull(), getIndex(), and isReadOnly(),
+ // and (2) you are in a hot path where you need to minimize the number of times
+ // that you branch on isFat() when getting the bits().
+ class Fast {
+ public:
+ Fast()
: m_bits(SlimFlag)
{
}
-
- SymbolTableEntry(int index)
- : m_bits(SlimFlag)
- {
- ASSERT(isValidIndex(index));
- pack(index, false, false);
- }
-
- SymbolTableEntry(int index, unsigned attributes)
- : m_bits(SlimFlag)
- {
- ASSERT(isValidIndex(index));
- pack(index, attributes & ReadOnly, attributes & DontEnum);
- }
- ~SymbolTableEntry()
+ ALWAYS_INLINE Fast(const SymbolTableEntry& entry)
+ : m_bits(entry.bits())
{
- freeFatEntry();
}
-
- SymbolTableEntry(const SymbolTableEntry& other)
- : m_bits(SlimFlag)
- {
- *this = other;
- }
-
- SymbolTableEntry& operator=(const SymbolTableEntry& other)
- {
- if (UNLIKELY(other.isFat()))
- return copySlow(other);
- freeFatEntry();
- m_bits = other.m_bits;
- return *this;
- }
-
+
bool isNull() const
{
- return !(bits() & ~SlimFlag);
+ return !(m_bits & ~SlimFlag);
}
int getIndex() const
{
- return static_cast<int>(bits() >> FlagBits);
+ return static_cast<int>(m_bits >> FlagBits);
}
-
- ALWAYS_INLINE Fast getFast() const
+
+ bool isReadOnly() const
{
- return Fast(*this);
+ return m_bits & ReadOnlyFlag;
}
- ALWAYS_INLINE Fast getFast(bool& wasFat) const
- {
- Fast result;
- wasFat = isFat();
- if (wasFat)
- result.m_bits = fatEntry()->m_bits | SlimFlag;
- else
- result.m_bits = m_bits;
- return result;
- }
-
unsigned getAttributes() const
{
- return getFast().getAttributes();
+ unsigned attributes = 0;
+ if (m_bits & ReadOnlyFlag)
+ attributes |= ReadOnly;
+ if (m_bits & DontEnumFlag)
+ attributes |= DontEnum;
+ return attributes;
}
- void setAttributes(unsigned attributes)
- {
- pack(getIndex(), attributes & ReadOnly, attributes & DontEnum);
- }
-
- bool isReadOnly() const
- {
- return bits() & ReadOnlyFlag;
- }
-
- bool couldBeWatched();
-
- // Notify an opportunity to create a watchpoint for a variable. This is
- // idempotent and fail-silent. It is idempotent in the sense that if
- // a watchpoint set had already been created, then another one will not
- // be created. Hence two calls to this method have the same effect as
- // one call. It is also fail-silent, in the sense that if a watchpoint
- // set had been created and had already been invalidated, then this will
- // just return. This means that couldBeWatched() may return false even
- // immediately after a call to attemptToWatch().
- void attemptToWatch();
-
- bool* addressOfIsWatched();
-
- void addWatchpoint(Watchpoint*);
-
- WatchpointSet* watchpointSet()
- {
- return fatEntry()->m_watchpoints.get();
- }
-
- ALWAYS_INLINE void notifyWrite()
- {
- if (LIKELY(!isFat()))
- return;
- notifyWriteSlow();
- }
-
- private:
- static const intptr_t SlimFlag = 0x1;
- static const intptr_t ReadOnlyFlag = 0x2;
- static const intptr_t DontEnumFlag = 0x4;
- static const intptr_t NotNullFlag = 0x8;
- static const intptr_t FlagBits = 4;
-
- class FatEntry {
- WTF_MAKE_FAST_ALLOCATED;
- public:
- FatEntry(intptr_t bits)
- : m_bits(bits & ~SlimFlag)
- {
- }
-
- intptr_t m_bits; // always has FatFlag set and exactly matches what the bits would have been if this wasn't fat.
-
- RefPtr<WatchpointSet> m_watchpoints;
- };
-
- SymbolTableEntry& copySlow(const SymbolTableEntry&);
- JS_EXPORT_PRIVATE void notifyWriteSlow();
-
bool isFat() const
{
return !(m_bits & SlimFlag);
}
- const FatEntry* fatEntry() const
+ private:
+ friend struct SymbolTableEntry;
+ intptr_t m_bits;
+ };
+
+ SymbolTableEntry()
+ : m_bits(SlimFlag)
+ {
+ }
+
+ SymbolTableEntry(int index)
+ : m_bits(SlimFlag)
+ {
+ ASSERT(isValidIndex(index));
+ pack(index, false, false);
+ }
+
+ SymbolTableEntry(int index, unsigned attributes)
+ : m_bits(SlimFlag)
+ {
+ ASSERT(isValidIndex(index));
+ pack(index, attributes & ReadOnly, attributes & DontEnum);
+ }
+
+ ~SymbolTableEntry()
+ {
+ freeFatEntry();
+ }
+
+ SymbolTableEntry(const SymbolTableEntry& other)
+ : m_bits(SlimFlag)
+ {
+ *this = other;
+ }
+
+ SymbolTableEntry& operator=(const SymbolTableEntry& other)
+ {
+ if (UNLIKELY(other.isFat()))
+ return copySlow(other);
+ freeFatEntry();
+ m_bits = other.m_bits;
+ return *this;
+ }
+
+ bool isNull() const
+ {
+ return !(bits() & ~SlimFlag);
+ }
+
+ int getIndex() const
+ {
+ return static_cast<int>(bits() >> FlagBits);
+ }
+
+ ALWAYS_INLINE Fast getFast() const
+ {
+ return Fast(*this);
+ }
+
+ ALWAYS_INLINE Fast getFast(bool& wasFat) const
+ {
+ Fast result;
+ wasFat = isFat();
+ if (wasFat)
+ result.m_bits = fatEntry()->m_bits | SlimFlag;
+ else
+ result.m_bits = m_bits;
+ return result;
+ }
+
+ unsigned getAttributes() const
+ {
+ return getFast().getAttributes();
+ }
+
+ void setAttributes(unsigned attributes)
+ {
+ pack(getIndex(), attributes & ReadOnly, attributes & DontEnum);
+ }
+
+ bool isReadOnly() const
+ {
+ return bits() & ReadOnlyFlag;
+ }
+
+ bool couldBeWatched();
+
+ // Notify an opportunity to create a watchpoint for a variable. This is
+ // idempotent and fail-silent. It is idempotent in the sense that if
+ // a watchpoint set had already been created, then another one will not
+ // be created. Hence two calls to this method have the same effect as
+ // one call. It is also fail-silent, in the sense that if a watchpoint
+ // set had been created and had already been invalidated, then this will
+ // just return. This means that couldBeWatched() may return false even
+ // immediately after a call to attemptToWatch().
+ void attemptToWatch();
+
+ bool* addressOfIsWatched();
+
+ void addWatchpoint(Watchpoint*);
+
+ WatchpointSet* watchpointSet()
+ {
+ return fatEntry()->m_watchpoints.get();
+ }
+
+ ALWAYS_INLINE void notifyWrite()
+ {
+ if (LIKELY(!isFat()))
+ return;
+ notifyWriteSlow();
+ }
+
+private:
+ static const intptr_t SlimFlag = 0x1;
+ static const intptr_t ReadOnlyFlag = 0x2;
+ static const intptr_t DontEnumFlag = 0x4;
+ static const intptr_t NotNullFlag = 0x8;
+ static const intptr_t FlagBits = 4;
+
+ class FatEntry {
+ WTF_MAKE_FAST_ALLOCATED;
+ public:
+ FatEntry(intptr_t bits)
+ : m_bits(bits & ~SlimFlag)
{
- ASSERT(isFat());
- return bitwise_cast<const FatEntry*>(m_bits);
}
- FatEntry* fatEntry()
- {
- ASSERT(isFat());
- return bitwise_cast<FatEntry*>(m_bits);
- }
+ intptr_t m_bits; // always has FatFlag set and exactly matches what the bits would have been if this wasn't fat.
- FatEntry* inflate()
- {
- if (LIKELY(isFat()))
- return fatEntry();
- return inflateSlow();
- }
-
- FatEntry* inflateSlow();
-
- ALWAYS_INLINE intptr_t bits() const
- {
- if (isFat())
- return fatEntry()->m_bits;
- return m_bits;
- }
-
- ALWAYS_INLINE intptr_t& bits()
- {
- if (isFat())
- return fatEntry()->m_bits;
- return m_bits;
- }
-
- void freeFatEntry()
- {
- if (LIKELY(!isFat()))
- return;
- freeFatEntrySlow();
- }
+ RefPtr<WatchpointSet> m_watchpoints;
+ };
+
+ SymbolTableEntry& copySlow(const SymbolTableEntry&);
+ JS_EXPORT_PRIVATE void notifyWriteSlow();
+
+ bool isFat() const
+ {
+ return !(m_bits & SlimFlag);
+ }
+
+ const FatEntry* fatEntry() const
+ {
+ ASSERT(isFat());
+ return bitwise_cast<const FatEntry*>(m_bits);
+ }
+
+ FatEntry* fatEntry()
+ {
+ ASSERT(isFat());
+ return bitwise_cast<FatEntry*>(m_bits);
+ }
+
+ FatEntry* inflate()
+ {
+ if (LIKELY(isFat()))
+ return fatEntry();
+ return inflateSlow();
+ }
+
+ FatEntry* inflateSlow();
+
+ ALWAYS_INLINE intptr_t bits() const
+ {
+ if (isFat())
+ return fatEntry()->m_bits;
+ return m_bits;
+ }
+
+ ALWAYS_INLINE intptr_t& bits()
+ {
+ if (isFat())
+ return fatEntry()->m_bits;
+ return m_bits;
+ }
+
+ void freeFatEntry()
+ {
+ if (LIKELY(!isFat()))
+ return;
+ freeFatEntrySlow();
+ }
- JS_EXPORT_PRIVATE void freeFatEntrySlow();
+ JS_EXPORT_PRIVATE void freeFatEntrySlow();
- void pack(int index, bool readOnly, bool dontEnum)
- {
- ASSERT(!isFat());
- intptr_t& bitsRef = bits();
- bitsRef = (static_cast<intptr_t>(index) << FlagBits) | NotNullFlag | SlimFlag;
- if (readOnly)
- bitsRef |= ReadOnlyFlag;
- if (dontEnum)
- bitsRef |= DontEnumFlag;
- }
-
- bool isValidIndex(int index)
- {
- return ((static_cast<intptr_t>(index) << FlagBits) >> FlagBits) == static_cast<intptr_t>(index);
- }
+ void pack(int index, bool readOnly, bool dontEnum)
+ {
+ ASSERT(!isFat());
+ intptr_t& bitsRef = bits();
+ bitsRef = (static_cast<intptr_t>(index) << FlagBits) | NotNullFlag | SlimFlag;
+ if (readOnly)
+ bitsRef |= ReadOnlyFlag;
+ if (dontEnum)
+ bitsRef |= DontEnumFlag;
+ }
+
+ bool isValidIndex(int index)
+ {
+ return ((static_cast<intptr_t>(index) << FlagBits) >> FlagBits) == static_cast<intptr_t>(index);
+ }
- intptr_t m_bits;
- };
+ intptr_t m_bits;
+};
- struct SymbolTableIndexHashTraits : HashTraits<SymbolTableEntry> {
- static const bool needsDestruction = true;
- };
+struct SymbolTableIndexHashTraits : HashTraits<SymbolTableEntry> {
+ static const bool needsDestruction = true;
+};
- typedef HashMap<RefPtr<StringImpl>, SymbolTableEntry, IdentifierRepHash, HashTraits<RefPtr<StringImpl> >, SymbolTableIndexHashTraits> SymbolTable;
+typedef HashMap<RefPtr<StringImpl>, SymbolTableEntry, IdentifierRepHash, HashTraits<RefPtr<StringImpl> >, SymbolTableIndexHashTraits> SymbolTable;
- class SharedSymbolTable : public JSCell, public SymbolTable {
- public:
- typedef JSCell Base;
+class SharedSymbolTable : public JSCell, public SymbolTable {
+public:
+ typedef JSCell Base;
- static SharedSymbolTable* create(VM& vm)
- {
- SharedSymbolTable* sharedSymbolTable = new (NotNull, allocateCell<SharedSymbolTable>(vm.heap)) SharedSymbolTable(vm);
- sharedSymbolTable->finishCreation(vm);
- return sharedSymbolTable;
- }
- static const bool needsDestruction = true;
- static const bool hasImmortalStructure = true;
- static void destroy(JSCell*);
+ static SharedSymbolTable* create(VM& vm)
+ {
+ SharedSymbolTable* sharedSymbolTable = new (NotNull, allocateCell<SharedSymbolTable>(vm.heap)) SharedSymbolTable(vm);
+ sharedSymbolTable->finishCreation(vm);
+ return sharedSymbolTable;
+ }
+ static const bool needsDestruction = true;
+ static const bool hasImmortalStructure = true;
+ static void destroy(JSCell*);
- static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
- {
- return Structure::create(vm, globalObject, prototype, TypeInfo(LeafType, StructureFlags), &s_info);
- }
+ static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+ {
+ return Structure::create(vm, globalObject, prototype, TypeInfo(LeafType, StructureFlags), &s_info);
+ }
- bool usesNonStrictEval() { return m_usesNonStrictEval; }
- void setUsesNonStrictEval(bool usesNonStrictEval) { m_usesNonStrictEval = usesNonStrictEval; }
+ bool usesNonStrictEval() { return m_usesNonStrictEval; }
+ void setUsesNonStrictEval(bool usesNonStrictEval) { m_usesNonStrictEval = usesNonStrictEval; }
- int captureStart() { return m_captureStart; }
- void setCaptureStart(int captureStart) { m_captureStart = captureStart; }
+ int captureStart() { return m_captureStart; }
+ void setCaptureStart(int captureStart) { m_captureStart = captureStart; }
- int captureEnd() { return m_captureEnd; }
- void setCaptureEnd(int captureEnd) { m_captureEnd = captureEnd; }
+ int captureEnd() { return m_captureEnd; }
+ void setCaptureEnd(int captureEnd) { m_captureEnd = captureEnd; }
- int captureCount() { return m_captureEnd - m_captureStart; }
+ int captureCount() { return m_captureEnd - m_captureStart; }
- int parameterCount() { return m_parameterCountIncludingThis - 1; }
- int parameterCountIncludingThis() { return m_parameterCountIncludingThis; }
- void setParameterCountIncludingThis(int parameterCountIncludingThis) { m_parameterCountIncludingThis = parameterCountIncludingThis; }
+ int parameterCount() { return m_parameterCountIncludingThis - 1; }
+ int parameterCountIncludingThis() { return m_parameterCountIncludingThis; }
+ void setParameterCountIncludingThis(int parameterCountIncludingThis) { m_parameterCountIncludingThis = parameterCountIncludingThis; }
- // 0 if we don't capture any arguments; parameterCount() in length if we do.
- const SlowArgument* slowArguments() { return m_slowArguments.get(); }
- void setSlowArguments(PassOwnArrayPtr<SlowArgument> slowArguments) { m_slowArguments = slowArguments; }
+ // 0 if we don't capture any arguments; parameterCount() in length if we do.
+ const SlowArgument* slowArguments() { return m_slowArguments.get(); }
+ void setSlowArguments(PassOwnArrayPtr<SlowArgument> slowArguments) { m_slowArguments = slowArguments; }
- static JS_EXPORTDATA const ClassInfo s_info;
+ static JS_EXPORTDATA const ClassInfo s_info;
- private:
- SharedSymbolTable(VM& vm)
- : JSCell(vm, vm.sharedSymbolTableStructure.get())
- , m_parameterCountIncludingThis(0)
- , m_usesNonStrictEval(false)
- , m_captureStart(0)
- , m_captureEnd(0)
- {
- }
+private:
+ SharedSymbolTable(VM& vm)
+ : JSCell(vm, vm.sharedSymbolTableStructure.get())
+ , m_parameterCountIncludingThis(0)
+ , m_usesNonStrictEval(false)
+ , m_captureStart(0)
+ , m_captureEnd(0)
+ {
+ }
- int m_parameterCountIncludingThis;
- bool m_usesNonStrictEval;
+ int m_parameterCountIncludingThis;
+ bool m_usesNonStrictEval;
- int m_captureStart;
- int m_captureEnd;
+ int m_captureStart;
+ int m_captureEnd;
- OwnArrayPtr<SlowArgument> m_slowArguments;
- };
+ OwnArrayPtr<SlowArgument> m_slowArguments;
+};
} // namespace JSC
