Review Request: Patch to reduce C++ memory consumption by removing DuContext* pointer from the AST

[Milian Wolff]

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shall we close this as discarded adymo?

- Milian


On 2010-02-15 11:48:01, Alexander Dymo wrote:
> 
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> http://reviewboard.kde.org/r/2938/
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> (Updated 2010-02-15 11:48:01)
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> 
> Review request for KDevelop.
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> 
> Summary
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> C++ parser's AST base class has "KDevelop::DUContext* ducontext" pointer which isn't used for most of the nodes. For example, the primary expression AST nodes do not open a new context and if your file is big, the memory is wasted.
> 
> This patch removes the context pointer from AST and instead fills a QMap<AST*, DuContext*> in the ParseSession class.
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> For me and my huge files this saves ~50M of memory.
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> Note, that the map will be ~2% slower than the pointer (when building uses for example). Performance testing results are below.
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> 
> Diffs
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> 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/cppduchain/contextbuilder.cpp 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/cppduchain/declarationbuilder.cpp 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/cppduchain/expressionparser.cpp 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/cppduchain/expressionvisitor.cpp 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/cppduchain/name_visitor.cpp 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/cppduchain/typebuilder.cpp 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/cppduchain/usebuilder.cpp 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/parser/ast.h 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/parser/parsesession.h 1090158 
>   /trunk/extragear/sdk/kdevelop/languages/cpp/parser/parsesession.cpp 1090158 
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> Diff: http://reviewboard.kde.org/r/2938/diff
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> 
> Testing
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> All tests pass.
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> Optimization results: my test files:
> before: 703M
> after: 655M
> 48M saved
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> 
> Performance testing:
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> kdevplatform:	peak memory	duchainify: visible-declarations	du: all-declarations-and-uses
> before:		150M		52					79.35
> after:		150M		52					81
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> kdevelop:	peak memory	duchainify: visible-declarations	du: all-declarations-and-uses
> before:		98M		22.86					41.77
> after:		98M		22.85					42.55
> 
> Performance regression for use-building is 2% due to this patch.
> For KDevelop and KDevplatform projects where there are no huge files, this patch doesn't save any memory.
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> 
> Thanks,
> 
> Alexander
> 
>