Re: [PATCH] gcc: Adjust gdbhooks.py VecPrinter for vec layout changes

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Mar 03, 2023 at 05:45:59PM +0100, Jakub Jelinek via Gcc-patches wrote:
> On Fri, Mar 03, 2023 at 04:44:39PM +0000, Jonathan Wakely via Gcc-patches wrote:
> > OK for trunk?
> > 
> > gcc/ChangeLog:
> > 
> 
> Please add
> 	PR middle-end/109006
> here
> > 	* gdbhooks.py (VecPrinter): Adjust for new vec layout.
> 
> Ok with that, thanks.

Though, trying it on another vector it doesn't work in that case.
Testcase:
int
foo (void)
{
  return 1;
}
gdb ./cc1 -quiet -O2 test.c
b pass_reassoc::execute
r
p debug_bb_n (2)
p $1->preds
(gdb) p $1->preds
$2 = 0x7fffea2d1f50 = {<error reading variable: Cannot access memory at address 0x100000058>}
(gdb) p $1->succs
$3 = 0x7fffea3010a0 = {<edge 0x0>}

But if I try to print it the hard way:
(gdb) p ((edge_def**)(&$1->preds.m_vecpfx+1))[0]
$4 = <edge 0x7fffea2fcdb0 (ENTRY -> 2)>
(gdb) p ((edge_def**)(&$1->succs.m_vecpfx+1))[0]
$5 = <edge 0x7fffea2fce70 (2 -> EXIT)>

> > diff --git a/gcc/gdbhooks.py b/gcc/gdbhooks.py
> > index c9dea9bf828..78e6c97c30d 100644
> > --- a/gcc/gdbhooks.py
> > +++ b/gcc/gdbhooks.py
> > @@ -461,7 +461,11 @@ class VecPrinter:
> >              return
> >          m_vecpfx = self.gdbval['m_vecpfx']
> >          m_num = m_vecpfx['m_num']
> > -        m_vecdata = self.gdbval['m_vecdata']
> > +        typ = self.gdbval.type
> > +        if typ.code == gdb.TYPE_CODE_PTR:
> > +            typ = typ.target()
> > +        typ = typ.template_argument(0) # the type T
> > +        m_vecdata = (self.gdbval.address + 1).cast(typ.pointer())
> >          for i in range(m_num):
> >              yield ('[%d]' % i, m_vecdata[i])

	Jakub