[fpc-devel] Re: Debugger for FPC

[Jonas Maebe]

Michael Schnell wrote on di, 17 mrt 2009:

> I still did not yet get any discussion rolling on the issue of "pure"
> read functions (that have no side-effect).

I did discuss it in my first mail to this thread. It first requires  
the following two problems to be solved, and none is particularly easy:

***
There are also multiple reasons for this:
a) we, nor anyone else, has defined an extension for DWARF to support  
Object Pascal properties, let alone implemented support for it in a  
debugger (although that may not even be necessary, it's quite possible  
that current gdb features combined with a to be developed Lazarus  
DWARF reader would be enough)
b) by default, FPC uses the (completely non-standard, afaik) Delphi  
calling convention on i386 (different from GCC's fastcall), which is  
not supported by gdb (until someone adds support for it). Hence, once  
you add property support to the debugging format (and possibly the  
debugger), you still have to teach the debugger about how this calling  
convention works so it can properly evaluate expressions containing  
calls. This is fortunately less of a problem on other architectures.
***

a) could also be reformulated as "nobody has defined an extension for  
DWARF to describe calling functions", although that's more general  
(since the possible signatures of getters/setters are limited).


Jonas

Jonas

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