Changeset 108943 in webkit for trunk/Source/JavaScriptCore/runtime/Executable.cpp

Timestamp:

Feb 26, 2012, 6:07:34 PM (13 years ago)

Author:

[email protected]

Message:

Getting the instruction stream for a code block should not require two loads
​https://bugs.webkit.org/show_bug.cgi?id=79608

Reviewed by Sam Weinig.

Introduced the RefCountedArray class, which contains a single inline pointer
to a ref-counted non-resizeable vector backing store. This satisfies the
requirements of CodeBlock, which desires the ability to share instruction
streams with other CodeBlocks. It also reduces the number of loads required
for getting the instruction stream by one.

This patch also gets rid of the bytecode discarding logic, since we don't
use it anymore and it's unlikely to ever work right with DFG or LLInt. And
I didn't feel like porting dead code to use RefCountedArray.

• GNUmakefile.list.am:
• JavaScriptCore.xcodeproj/project.pbxproj:
• bytecode/CodeBlock.cpp:

(JSC::instructionOffsetForNth):
(JSC::CodeBlock::dump):
(JSC::CodeBlock::CodeBlock):
(JSC::CodeBlock::finalizeUnconditionally):
(JSC::CodeBlock::handlerForBytecodeOffset):
(JSC::CodeBlock::lineNumberForBytecodeOffset):
(JSC::CodeBlock::expressionRangeForBytecodeOffset):
(JSC::CodeBlock::shrinkToFit):

• bytecode/CodeBlock.h:

(CodeBlock):
(JSC::CodeBlock::numberOfInstructions):
(JSC::CodeBlock::instructions):
(JSC::CodeBlock::instructionCount):
(JSC::CodeBlock::valueProfileForBytecodeOffset):
(JSC):

• bytecompiler/BytecodeGenerator.cpp:

(JSC::Label::setLocation):
(JSC):
(JSC::BytecodeGenerator::generate):
(JSC::BytecodeGenerator::newLabel):

• bytecompiler/BytecodeGenerator.h:

(JSC):
(BytecodeGenerator):
(JSC::BytecodeGenerator::instructions):

• bytecompiler/Label.h:

(JSC::Label::Label):
(Label):

• dfg/DFGByteCodeCache.h:

(JSC::DFG::ByteCodeCache::~ByteCodeCache):
(JSC::DFG::ByteCodeCache::get):

• jit/JITExceptions.cpp:

(JSC::genericThrow):

• llint/LowLevelInterpreter32_64.asm:
• runtime/Executable.cpp:

(JSC::EvalExecutable::compileInternal):
(JSC::ProgramExecutable::compileInternal):
(JSC::FunctionExecutable::codeBlockWithBytecodeFor):
(JSC::FunctionExecutable::produceCodeBlockFor):

• wtf/RefCountedArray.h: Added.

(WTF):
(RefCountedArray):
(WTF::RefCountedArray::RefCountedArray):
(WTF::RefCountedArray::operator=):
(WTF::RefCountedArray::~RefCountedArray):
(WTF::RefCountedArray::size):
(WTF::RefCountedArray::data):
(WTF::RefCountedArray::begin):
(WTF::RefCountedArray::end):
(WTF::RefCountedArray::at):
(WTF::RefCountedArray::operator[]):
(Header):
(WTF::RefCountedArray::Header::size):
(WTF::RefCountedArray::Header::payload):
(WTF::RefCountedArray::Header::fromPayload):

• wtf/Platform.h:

File:

• trunk/Source/JavaScriptCore/runtime/Executable.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/runtime/Executable.cpp

@@ -211 +211 @@
     JSGlobalObject* lexicalGlobalObject = exec->lexicalGlobalObject();
     
-    if (!!m_evalCodeBlock && m_evalCodeBlock->canProduceCopyWithBytecode()) {
-        BytecodeDestructionBlocker blocker(m_evalCodeBlock.get());
+    if (!!m_evalCodeBlock) {
         OwnPtr<EvalCodeBlock> newCodeBlock = adoptPtr(new EvalCodeBlock(CodeBlock::CopyParsedBlock, *m_evalCodeBlock));
         newCodeBlock->setAlternative(static_pointer_cast<CodeBlock>(m_evalCodeBlock.release()));
@@ -347 +346 @@
     JSGlobalObject* lexicalGlobalObject = exec->lexicalGlobalObject();
     
-    if (!!m_programCodeBlock && m_programCodeBlock->canProduceCopyWithBytecode()) {
-        BytecodeDestructionBlocker blocker(m_programCodeBlock.get());
+    if (!!m_programCodeBlock) {
         OwnPtr<ProgramCodeBlock> newCodeBlock = adoptPtr(new ProgramCodeBlock(CodeBlock::CopyParsedBlock, *m_programCodeBlock));
         newCodeBlock->setAlternative(static_pointer_cast<CodeBlock>(m_programCodeBlock.release()));
@@ -495 +493 @@
 FunctionCodeBlock* FunctionExecutable::codeBlockWithBytecodeFor(CodeSpecializationKind kind)
 {
-    FunctionCodeBlock* codeBlock = baselineCodeBlockFor(kind);
-    if (codeBlock->canProduceCopyWithBytecode())
-        return codeBlock;
-    return 0;
+    return baselineCodeBlockFor(kind);
 }
 
 PassOwnPtr<FunctionCodeBlock> FunctionExecutable::produceCodeBlockFor(ScopeChainNode* scopeChainNode, CompilationKind compilationKind, CodeSpecializationKind specializationKind, JSObject*& exception)
 {
-    if (!!codeBlockFor(specializationKind) && codeBlockFor(specializationKind)->canProduceCopyWithBytecode()) {
-        BytecodeDestructionBlocker blocker(codeBlockFor(specializationKind).get());
+    if (!!codeBlockFor(specializationKind))
         return adoptPtr(new FunctionCodeBlock(CodeBlock::CopyParsedBlock, *codeBlockFor(specializationKind)));
-    }
     
     exception = 0;