[fpc-devel] (patch) Rework of string literals codegeneration
sergei_gorelkin at mail.ru
Sun Aug 24 23:44:31 CEST 2008
The attached patch contains three improvements of code generation for
1) Replaces linear search through assembler list by the hash lookup.
This considerably improves performance on large projects (one example is
winunits-jedi package, in which tcgstringconstnode.pass_generate_code
was top #1 in calltree, consuming about 12% IRefs).
2) Enables reusing memory locations for widestring constants (and in
general, the same approach may be used for any other type of constants).
3) Saves a sizeof(pointer) bytes per constant, by removing a location
which points to the string. This location is necessary for the typed
consts which may be modified, but redundant for string literals because
the language does not allow to modify string literals in any way.
The patch may break Darwin targets - I am not sure how the assembler
reference directives generated for Darwin should be handled, and
unfortunately I'm unable to test it. Hope it wouldn't be much trouble to
fix if necessary.
TFPHashList wasn't suitable for the task because of its ShortString
limitation, therefore I introduced another container named THashSet. It
has no indexed access, but uses arbitrary data (which it may own or
reference, depending on the flag passed to constructor) for keys.
The patch also contains a speed improvement fix to TCmdStrList.Find.
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 5160 bytes
Desc: not available
More information about the fpc-devel