Changeset 47571 in webkit for trunk/JavaScriptCore/parser/ParserArena.h

Timestamp:

Aug 20, 2009, 7:24:49 AM (16 years ago)

Author:

Darin Adler

Message:

Syntax tree nodes should use arena allocation
​https://bugs.webkit.org/show_bug.cgi?id=25674

Patch by Darin Adler <Darin Adler> on 2009-08-20
Reviewed by Gavin Barraclough.

Use an actual arena now. 0.7% speedup on SunSpider.

• JavaScriptCore.exp: Removed FunctionBodyNode::create, which no

longer needs to be used outside JavaScriptCore.

• JavaScriptCore.xcodeproj/project.pbxproj: Made Nodes.h and

Executable.h project-internal instead of "private".

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::BytecodeGenerator): Updated since VarStack
contains const Identifier* now.

• parser/Grammar.y: Made identifiers from the lexer be const

Identifier* and updated since VarStack contains const Identifier* now.

• parser/Lexer.cpp:

(JSC::Lexer::setCode): Pass in ParserArena, used for identifiers.
(JSC::Lexer::makeIdentifier): Changed return type to const Identifier*
and changed to call ParserArena.
(JSC::Lexer::clear): Removed the code to manage m_identifiers and
added code to set m_arena to 0.

• parser/Lexer.h: Updated for changes above.

• parser/NodeConstructors.h:

(JSC::ParserArenaFreeable::operator new): Added. Calls allocateFreeable
on the arena.
(JSC::ParserArenaDeletable::operator new): Changed to call the
allocateDeletable function on the arena instead of deleteWithArena.
(JSC::PropertyNode::PropertyNode): Added new constructor that makes
numeric identifiers. Some day we might want to optimize this for
integers so it doesn't create a string for each one.
(JSC::ContinueNode::ContinueNode): Initialize m_ident to nullIdentifier
since it's now a const Identifier& so it can't be left uninitialized.
(JSC::BreakNode::BreakNode): Ditto.
(JSC::CaseClauseNode::CaseClauseNode): Updated to use SourceElements*
to keep track of the statements rather than a separate statement vector.
(JSC::BlockNode::BlockNode): Ditto.
(JSC::ForInNode::ForInNode): Initialize m_ident to nullIdentifier.

• parser/Nodes.cpp: Moved the comment explaining emitBytecode in here.

It seemed strangely out of place in the header.
(JSC::ThrowableExpressionData::emitThrowError): Added an overload for
UString as well as Identifier.
(JSC::SourceElements::singleStatement): Added.
(JSC::SourceElements::lastStatement): Added.
(JSC::RegExpNode::emitBytecode): Changed the throwError code to use
the substitution mechanism instead of doing a string append.
(JSC::SourceElements::emitBytecode): Added. Replaces the old
statementListEmitCode function, since we now keep the SourceElements
objects around.
(JSC::BlockNode::lastStatement): Added.
(JSC::BlockNode::emitBytecode): Changed to use emitBytecode instead of
statementListEmitCode.
(JSC::CaseClauseNode::emitBytecode): Added.
(JSC::CaseBlockNode::emitBytecodeForBlock): Changed to use emitBytecode
instead of statementListEmitCode.
(JSC::ScopeNodeData::ScopeNodeData): Changed to store the
SourceElements* instead of using releaseContentsIntoVector.
(JSC::ScopeNode::emitStatementsBytecode): Added.
(JSC::ScopeNode::singleStatement): Added.
(JSC::ProgramNode::emitBytecode): Call emitStatementsBytecode instead
of statementListEmitCode.
(JSC::EvalNode::emitBytecode): Ditto.
(JSC::FunctionBodyNode::emitBytecode): Call emitStatementsBytecode
insetad of statementListEmitCode and check for the return node using
the new functions.

• parser/Nodes.h: Changed VarStack to store const Identifier* instead

of Identifier and rely on the arena to control lifetime. Added a new
ParserArenaFreeable class. Made ParserArenaDeletable inherit from
FastAllocBase instead of having its own operator new. Base the Node
class on ParserArenaFreeable. Changed the various Node classes
to use const Identifier& instead of Identifier to avoid the need to
call their destructors and allow them to function as "freeable" in the
arena. Removed extraneous JSC_FAST_CALL on definitions of inline functions.
Changed ElementNode, PropertyNode, ArgumentsNode, ParameterNode,
CaseClauseNode, ClauseListNode, and CaseBlockNode to use ParserArenaFreeable
as a base class since they do not descend from Node. Eliminated the
StatementVector type and instead have various classes use SourceElements*
instead of StatementVector. This prevents those classes from having to
use ParserArenaDeletable to make sure the vector destructor is called.

• parser/Parser.cpp:

(JSC::Parser::parse): Pass the arena to the lexer.

• parser/Parser.h: Added an include of ParserArena.h, which is no longer

included by Nodes.h.
(JSC::Parser::parseFunctionFromGlobalCode): Changed to use the
singleStatement function, since there is no longer any children function.
Removed some unneeded use of RefPtr.

• parser/ParserArena.cpp:

(JSC::ParserArena::ParserArena): Added. Initializes the new members,
m_freeableMemory, m_freeablePoolEnd, and m_identifiers.
(JSC::ParserArena::freeablePool): Added. Computes the pool pointer,
since we store only the current pointer and the end of pool pointer.
(JSC::ParserArena::deallocateObjects): Added. Contains the common
memory-deallocation logic used by both the destructor and the
reset function.
(JSC::ParserArena::~ParserArena): Changed to call deallocateObjects.
(JSC::ParserArena::reset): Ditto. Also added code to zero out the
new structures, and switched to use clear() instead of shrink(0) since
we don't really reuse arenas.
(JSC::ParserArena::makeNumericIdentifier): Added.
(JSC::ParserArena::allocateFreeablePool): Added. Used when the pool
is empty.
(JSC::ParserArena::isEmpty): Added. No longer inline, which is fine
since this is used only for assertions at the moment.

• parser/ParserArena.h: Added an actual arena of "freeable" objects,

ones that don't need destructors to be called. Also added a separate
IdentifierArena object, a segmented vector of identifiers that used
to be in the Lexer.

• runtime/Executable.h: Moved the definition of the

FunctionExecutable::make function here. It can't go in JSFunction.h
since that header has to be used outside JavaScriptCore and so can't
include this, which includes Nodes.h. The function could be moved
elswhere if we don't want to include JSFunction.h in this header, but
for now this seems to be the best place.

• runtime/JSFunction.h: Removed the include of Executable.h and

definition of the FunctionExecutable::make function.

• wtf/FastMalloc.cpp: Fixed an incorrect comment.

File:

• trunk/JavaScriptCore/parser/ParserArena.h (modified) (2 diffs)

trunk/JavaScriptCore/parser/ParserArena.h

@@ -27 +27 @@
 #define ParserArena_h
 
-#include <wtf/PassRefPtr.h>
-#include <wtf/RefPtr.h>
-#include <wtf/Vector.h>
+#include "Identifier.h"
+#include <wtf/SegmentedVector.h>
 
 namespace JSC {
@@ -36 +35 @@
     class ParserArenaRefCounted;
 
-    class ParserArena {
+    class IdentifierArena {
     public:
+        ALWAYS_INLINE const Identifier& makeIdentifier(JSGlobalData*, const UChar* characters, size_t length);
+        const Identifier& makeNumericIdentifier(JSGlobalData*, double number);
+
+        void clear() { m_identifiers.clear(); }
+        bool isEmpty() const { return m_identifiers.isEmpty(); }
+
+    private:
+        typedef SegmentedVector<Identifier, 64> IdentifierVector;
+        IdentifierVector m_identifiers;
+    };
+
+    ALWAYS_INLINE const Identifier& IdentifierArena::makeIdentifier(JSGlobalData* globalData, const UChar* characters, size_t length)
+    {
+        m_identifiers.append(Identifier(globalData, characters, length));
+        return m_identifiers.last();
+    }
+
+    inline const Identifier& IdentifierArena::makeNumericIdentifier(JSGlobalData* globalData, double number)
+    {
+        m_identifiers.append(Identifier(globalData, UString::from(number)));
+        return m_identifiers.last();
+    }
+
+    class ParserArena : Noncopyable {
+    public:
+        ParserArena();
+        ~ParserArena();
+
         void swap(ParserArena& otherArena)
         {
+            std::swap(m_freeableMemory, otherArena.m_freeableMemory);
+            std::swap(m_freeablePoolEnd, otherArena.m_freeablePoolEnd);
+            m_identifierArena.swap(otherArena.m_identifierArena);
+            m_freeablePools.swap(otherArena.m_freeablePools);
             m_deletableObjects.swap(otherArena.m_deletableObjects);
             m_refCountedObjects.swap(otherArena.m_refCountedObjects);
         }
-        ~ParserArena();
 
-        void deleteWithArena(ParserArenaDeletable* object) { m_deletableObjects.append(object); }
+        void* allocateFreeable(size_t size)
+        {
+            ASSERT(size);
+            ASSERT(size <= freeablePoolSize);
+            size_t alignedSize = alignSize(size);
+            ASSERT(alignedSize <= freeablePoolSize);
+            if (UNLIKELY(static_cast<size_t>(m_freeablePoolEnd - m_freeableMemory) < alignedSize))
+                allocateFreeablePool();
+            void* block = m_freeableMemory;
+            m_freeableMemory += alignedSize;
+            return block;
+        }
+
+        void* allocateDeletable(size_t size)
+        {
+            ParserArenaDeletable* deletable = static_cast<ParserArenaDeletable*>(fastMalloc(size));
+            m_deletableObjects.append(deletable);
+            return deletable;
+        }
+
         void derefWithArena(PassRefPtr<ParserArenaRefCounted> object) { m_refCountedObjects.append(object); }
-
         bool contains(ParserArenaRefCounted*) const;
         ParserArenaRefCounted* last() const;
         void removeLast();
 
-        bool isEmpty() const { return m_deletableObjects.isEmpty() && m_refCountedObjects.isEmpty(); }
+        bool isEmpty() const;
         void reset();
 
+        IdentifierArena& identifierArena() { return *m_identifierArena; }
+
     private:
+        static const size_t freeablePoolSize = 8000;
+
+        static size_t alignSize(size_t size)
+        {
+            return (size + sizeof(WTF::AllocAlignmentInteger) - 1) & ~(sizeof(WTF::AllocAlignmentInteger) - 1);
+        }
+
+        void* freeablePool();
+        void allocateFreeablePool();
+        void deallocateObjects();
+
+        char* m_freeableMemory;
+        char* m_freeablePoolEnd;
+
+        OwnPtr<IdentifierArena> m_identifierArena;
+        Vector<void*> m_freeablePools;
         Vector<ParserArenaDeletable*> m_deletableObjects;
         Vector<RefPtr<ParserArenaRefCounted> > m_refCountedObjects;