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Re: recursive bug in dwarf2read.c
- From: Gaius Mulley <gaius at glam dot ac dot uk>
- To: gdb-patches at sourceware dot org
- Cc: drow at false dot org
- Date: Thu, 10 Dec 2009 19:39:02 +0000
- Subject: Re: recursive bug in dwarf2read.c
- References: <878wdcto0t.fsf@j228-gm.comp.glam.ac.uk> <20091209185157.GA29691@caradoc.them.org>
Daniel Jacobowitz <drow@false.org> writes:
> On Wed, Dec 09, 2009 at 10:55:30AM +0000, Gaius Mulley wrote:
>>
>> Hi,
>>
>> I think there is a bug in dwarf2read.c which can be exposed by
>> attempting to set a break point at RealIO_WriteFixed in this
>> executable.
>>
>> I acknowledge the (gnu modula-2 generated executable) could probably
>> be at fault, nevertheless it does contain cyclic data structures which
>> are not explicitly created in the same way as C. For example:
>>
>>
>> TYPE
>> ScanState = PROCEDURE (CHAR, VAR ScanClass, VAR ScanState);
>
> See e.g. this from read_structure_type:
>
> /* We need to add the type field to the die immediately so we don't
> infinitely recurse when dealing with pointers to the structure
> type within the structure itself. */
> set_die_type (die, type, cu);
>
> It looks as if read_subroutine_type does not do that, but now has to.
Hi Daniel,
here is a patch which fixes the bug above. Embarrassingly after
checking my private gdb directories I found I fixed this last year
and sat on and forgot the patch. Guess there is a moral here
somewhere..
2009-12-10 Gaius Mulley <gaius@glam.ac.uk>
* dwarf2read.c (read_subroutine_type): Add the subroutine
type to the die immediately to allow a parameter type to be
the same subroutine type.
--- src-orig/gdb/dwarf2read.c 2009-12-10 16:41:40.000000000 +0000
+++ src/gdb/dwarf2read.c 2009-12-10 17:04:16.000000000 +0000
@@ -5879,6 +5879,11 @@
the default value DW_CC_normal. */
attr = dwarf2_attr (die, DW_AT_calling_convention, cu);
TYPE_CALLING_CONVENTION (ftype) = attr ? DW_UNSND (attr) : DW_CC_normal;
+
+ /* We need to add the subroutine type to the die immediately so
+ we don't infinitely recurse when dealing with parameters
+ declared as the same subroutine type. */
+ set_die_type (die, ftype, cu);
if (die->child != NULL)
{
I've ran the testsuite on a AMD64 debian stable (lenny) system and and
it doesn't appear to cause any regression. I've also some minor
Modula-2 language support improvement patches which I wrote in Sept
which I'll now push out to the mailing list..
regards,
Gaius