Am 04.03.2013 13:46, schrieb Michael Van Canneyt:
On Mon, 4 Mar 2013, Sven Barth wrote:
Am 04.03.2013 13:38, schrieb Daniël Mantione:
1. Operator overloading
Operators are some of the most common tokens in source code. Without
operator overloading, if you parse an operator, you simply generate
a tree node.
With operator overloading, for each operator that you parse, you
have to traverse all loaded units to check if the operator is
overloaded. If there are 50 units loaded, this means 50 symtable
lookups, simply because the operator might be overloaded.
For each operator overload candidate that is found, the compiler has
need to check for many possible type conversions to see if the
candidate can actually be used.
The situation with Pascal type conversion has grown increasingly
complex over the years. For example almost any type can be converted
into a variant, and a variant can be converted into almost any type.
This requires all kinds of special handling, not only to do the
right thing, but also not to do ineffcient type conversions.
So even if you don't use operator overloading or variants at all,
they do affect the compiler speed.
Maybe we can improve this situation. For class helpers I added the
possibility to add flags to symtables (so that only units are checked
that really contain class helpers). Maybe we can add an additional
"has_operators" flag and ignore all units when searching for
overloads that don't have this flag set (the flag would propagate
from the symtable of e.g. advanced records up to the unit symtable
when parsing the record's declaration). As most units don't declare
operators this could result in a little speedup especially
considering that the lookup is done on each operator... and then we
might add some caching structures to improve this further.
That seems simple enough to implement and test ?
Yes, maybe I'll give it a try in the next couple days (if no one beats
me :) ).
Regards,
Sven
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