Bug 86435 – CodeBlock::CodeBlock() wastes a lot of Vector capacity in the m_argumentValueProfiles vector

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: JavaScriptCore

[Simon Fraser (smfr)]

Data collected via bug 86281 show that a lot of vector capacity is wasted via the Vector allocated here:


1996 vectors, 134.75KB used of 998.00KB, 863.25KB wasted at:
1   0x1069acb15 WTF::Vector<JSC::ValueProfile, 0ul>::Vector()
2   0x10699c7c5 WTF::Vector<JSC::ValueProfile, 0ul>::Vector()
3   0x106995898 JSC::CodeBlock::CodeBlock(JSC::ScriptExecutable*, JSC::CodeType, JSC::JSGlobalObject*, WTF::PassRefPtr<JSC::SourceProvider>, unsigned int, WTF::HashMap<WTF::RefPtr<WTF::StringImpl>, JSC::SymbolTableEntry, JSC::IdentifierRepHash, WTF::HashTraits<WTF::RefPtr<WTF::StringImpl> >, JSC::SymbolTableIndexHashTraits>*, bool, WTF::PassOwnPtr<JSC::CodeBlock>)
4   0x106a9ea22 JSC::FunctionCodeBlock::FunctionCodeBlock(JSC::FunctionExecutable*, JSC::CodeType, JSC::JSGlobalObject*, WTF::PassRefPtr<JSC::SourceProvider>, unsigned int, bool, WTF::PassOwnPtr<JSC::CodeBlock>)
5   0x106a97ab8 JSC::FunctionCodeBlock::FunctionCodeBlock(JSC::FunctionExecutable*, JSC::CodeType, JSC::JSGlobalObject*, WTF::PassRefPtr<JSC::SourceProvider>, unsigned int, bool, WTF::PassOwnPtr<JSC::CodeBlock>)

[Filip Pizlo]

I am tempted to relate this to https://bugs.webkit.org/show_bug.cgi?id=86436, but I need to investigate this more.  It appears that the pattern we're using to add parameters in the bytecode generator makes it really had to get the capacity of the m_argumentValueProfiles vector right.

[Filip Pizlo]

Yup, it's an easy fix so I'll dup it and fix in one patch along with the other CodeBlock vector capacity bugs.

*** This bug has been marked as a duplicate of bug 86436 ***