https://bugs.webkit.org/show_bug.cgi?id=115594

Reviewed by Geoffrey Garen.

This makes it possible to have the currently-being-compiled CodeBlock not be
installed in Executable, while also allowing it to point to its intended
alternative(). So long as we were using ownership and not reference counting, it
would have been difficult to have both CodeBlock::m_alternative and
Executable::m_codeBlockForBlah point to the previous CodeBlock.

I also took the opportunity to clean up a bunch of code that appears to have
rotted.

* assembler/MacroAssemblerCodeRef.h:
(MacroAssemblerCodePtr):
(JSC::MacroAssemblerCodePtr::operator==):
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::CodeBlock):
* bytecode/CodeBlock.h:
(JSC::CodeBlock::releaseAlternative):
(JSC::CodeBlock::setAlternative):
(CodeBlock):
(JSC::GlobalCodeBlock::GlobalCodeBlock):
(JSC::ProgramCodeBlock::ProgramCodeBlock):
(JSC::EvalCodeBlock::EvalCodeBlock):
(JSC::FunctionCodeBlock::FunctionCodeBlock):
* heap/DFGCodeBlocks.cpp:
(JSC::DFGCodeBlocks::~DFGCodeBlocks):
(JSC::DFGCodeBlocks::jettison):
(JSC::DFGCodeBlocks::deleteUnmarkedJettisonedCodeBlocks):
* heap/DFGCodeBlocks.h:
(DFGCodeBlocks):
* heap/Heap.cpp:
(JSC::Heap::jettisonDFGCodeBlock):
* heap/Heap.h:
* jit/JITDriver.h:
(JSC::jitCompileIfAppropriate):
(JSC::jitCompileFunctionIfAppropriate):
* runtime/Executable.cpp:
(JSC::jettisonCodeBlock):
(JSC::EvalExecutable::jitCompile):
(JSC::EvalExecutable::compileInternal):
(JSC::ProgramExecutable::jitCompile):
(JSC::ProgramExecutable::compileInternal):
(JSC::FunctionExecutable::jitCompileForCall):
(JSC::FunctionExecutable::jitCompileForConstruct):
(JSC::FunctionExecutable::produceCodeBlockFor):
(JSC::FunctionExecutable::compileForCallInternal):
(JSC::FunctionExecutable::compileForConstructInternal):
* runtime/Executable.h:
(EvalExecutable):
(FunctionExecutable):
(JSC::FunctionExecutable::codeBlockFor):
* runtime/ExecutionHarness.h:
(JSC::prepareForExecution):
(JSC::prepareFunctionForExecution):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153147 268f45cc-cd09-0410-ab3c-d52691b4dbfc