Re: Strange error message from gdb

[Andrew Haley <aph at redhat dot com>]

Daniel Jacobowitz writes:
 > On Wed, Dec 19, 2007 at 05:54:10PM +0000, Andrew Haley wrote:
 > >  > That DIE doesn't have any content.  It says "I am a declartion of an
 > >  > interface".  But not which interface or what it's called or what the
 > >  > type is.
 > > 
 > > Well, the type is the interface: there's nothing else it might be.
 > 
 > >From the DWARF standard:
 > 
 >  Interface types are represented by debugging information entries with
 >  the tag DW_TAG_interface_type.
 > 
 >  An interface type entry has a DW_AT_name attribute, whose value is a
 >  null-terminated string containing the type name as it appears in the
 >  source program.
 > 
 >  The members of an interface are represented by debugging information
 >  entries that are owned by the interface type entry and that appear in
 >  the same order as the corresponding declarations in the source
 >  program.

OK, so the name is missing, and that's wrong.  I should find out why.

 > So this is a declaration of an interface, but without a name.  GDB is
 > doing the wrong thing with it, but it still seems wrong to me.  Or do
 > Java interfaces have no name?
 > 
 > > Anyway, on inspection it seems like read_type_die() in dwarf2read.c
 > > doesn't know how to handle DW_TAG_interface_type.  This is rather odd,
 > > given that dwarf_tag_name() does know about interface types.
 > 
 > That's just a complete transcription of the DWARF tags (at some point
 > in history).

Right, so read_type_die() doesn't know how to handle
DW_TAG_interface_type.  The weird thing is that I have never seen this
error mesage before today, and AFAIAA gcj has been generating these
interface types for a long while.

It seems to me that even if gcj did generate the name for the
interface, gdb would still die because it doesn't have any handlers
for DW_TAG_interface_type in dwarf2read.c

Andrew.

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