shrinkToFit() is often not called for Vectors in CodeBlock
https://bugs.webkit.org/show_bug.cgi?id=86436
Source/JavaScriptCore:
Reviewed by Oliver Hunt.
The vectors in CodeBlock are often appended to during various stages of
compilation, but we neglect to shrink them after compilation finishes. This
patch takes the most brutal possible approach: shrink all the vectors after
the bytecompile phase, and then shrink them again after the appropriate
JITing phase. The two shrinks are necessary because the JIT may append more
stuff, but may also generate code that directly references things in other
vectors; hence some can only be shrunk before JIT and some after. Also,
we may allow a CodeBlock to sit around for a long time - possibly forever -
before invoking the JIT, hence it makes sense to have two shrinks.
This is performance neutral on the major benchmarks we track.
(JSC::CodeBlock::shrinkToFit):
(CodeBlock):
(JSC::CodeBlock::appendWeakReferenceTransition):
- bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::generate):
(JSC::DFG::compile):
(JSC::DFG::JITCompiler::link):
(JSC::JIT::privateCompile):
Source/WTF:
Reviewed by NOBODY (OOPS!).
Gave SegmentedVector a shrinkToFit() method. This only shrinks the segment
lookup table, which is likely to not be hugely profitable, but it is better
than nothing.
(SegmentedVector):
(WTF::SegmentedVector::shrinkToFit):
