[fpc-devel] New Windows gdb-binary

[Joost van der Sluis]

On Sun, 2011-10-02 at 14:29 +0100, Martin wrote:
> On 02/10/2011 14:05, Joost van der Sluis wrote:
> > On Sat, 2011-10-01 at 09:08 +0200, Joost van der Sluis wrote:
> >> On Sat, 2011-10-01 at 01:05 +0100, Martin wrote:
> >>> Ok, seems to have big issues with strings in fields. 
> >> Ow, man.. That's probably difficult again. While evaluating values, it
> >> does not 'recurse' into the structure, but uses all kinds of
> >> work-arounds. (For example: an array of strings wasn't working either)
> > It was easier then I thought. The recursive calls were ok, but you did a
> > 'ptype class.stringprop'. But when evaluating the type, there was
> > object-address set (which is logical)
> >
> > New version:
> > http://www.lazarussupport.com/gdb_lazarssupport_20111002.zip
> 
> Thanks, I will test.

(To test the function-calls you have to do 'set cp-abi gnu-v3' I forgot
to set that as the default. Will place a new version which does that
later)

> > There are more things that we need to discuss, though.
> >
> > For example, when I want to evaluate 'object.stringprop', Lazarus issues
> > a '-data-evaluate-expression object.stringprop^', which obviously won't
> > work with that '^' in the end.
> 
> Afaik it should fallback to omit it.
> 
> Anyway, those "gdb workarounds" that Lazarus does, will be updated, as 
> soon as the major gdb crashes are gone.

btw: I could not reproduce the external-linker and stabs crashes. Can
you give me some more info?

> IIRC, Lazarus uses the ptype result, to detect if the 
> variable/expression, is of an "internal pointer" type (object, 
> dyn-array, string). If so, it will attempt the "^" postfix.
> 
> This is important for:
> - objects, without the "^" gdb only reports the address, but with it, 
> all the values of all the fields are listed. (afaik this still aplies 
> iin dwarf 3)

Yes, when I changed that people started to complain. I don't know
anymore what the exact reason for those complaints was. Maybe because a
object really is a pointer, or that with this change it got impossible
to obtain the address.

>    And (also afaik) this behaviour is important, as it allows for 
> expressions like "Obj1=Obj2" to work the way it is pascal-expectation. 

Maybe that this was the reason...

> Such expression are used in breakpoint-conditions.
> - dyn array: to be tested under dwarf 3, probably no longer needing the 
> "^". with dwarf2 dyn array do need the "^"
> - strings: little tested, they are treated as dyn array of chars.
> 
> Obviously, with dwarf3 strings may be improved, and the IDE will get 
> better detection.
> 
> In dwarf2/stabs they are reported as "^(array of char)" which could also 
> be dyn-array.
> It is possible to get the type-name, but:
> - the user may have aliased it: "type MyAnsi = type Ansistring;"
> - the user may have a local type "type Ansistring = array of char;" 
> (0-based)

We should find a way to detect if -gw3 is used. Then you don't need
those adaptations for strings anymore. Just do 'p variable', it will
always give the right result.

Joost.

-- 
My Lazarus blog: http://www.lazarussupport.com/lazarus/weblog