Op Mon, 4 Mar 2013, schreef luiz americo pereira camara:
Is the bigger code just a side effect of a cross platform RTL or the
generated code is really bigger / slower?
There are again multiple reasons. One is indeed that the code is
multiple-platform and therefore some abstraction exist in the RTL. For
example, widestring and threat managers mean more code, but make things
more flexible.
Further: FPC tries to implement every Delphi feature, but also has unique
features. Some of these unique features require runtime overhead and thus
cause a bigger RTL.
Assembler implementations can reduce the size of the RTL, but FPC tries to
focus on portability and has therefore relatively less assembler in the
RTL.
Code generation quality is another factor. While FPC has in absolute terms
more optimization power than Delphi, it misses a few crucial
optimizations. For example, we don't have loop induction, which allows
Delphi to beat FPC in code that stresses this.
Further, especially regarding Lazarus, the design of the LCL simply means
that a lot of code is pulled into the executable. The Delphi VCL offers
more possibilities for smart linking away unneeded code.
Daniël
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