target/6522: Incorrect struct offset for unaligned 64-bit fields in debug information

[Jakub Jelinek]

On Thu, May 02, 2002 at 09:32:08PM -0400, Daniel Jacobowitz wrote:
> On Tue, Apr 30, 2002 at 11:30:38PM -0000, jakub@gcc.gnu.org wrote:
> > Synopsis: Incorrect struct offset for unaligned 64-bit fields in debug information
> > 
> > State-Changed-From-To: open->feedback
> > State-Changed-By: jakub
> > State-Changed-When: Tue Apr 30 16:30:37 2002
> > State-Changed-Why:
> >     You have not provided t64.cpp (or better t64.ii if t64.cpp
> >     includes some headers).
> > 
> > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6522
> 
> I can confirm this in 3.1.  It's present in 3.0, but worked in 2.95.3. 
> It's quite annoying, since GDB can't infer the right answer.

Reproduced, looking into it.

> Here's another example:
> 
> typedef __complex__ float cf;
> struct x { char c; cf f; } __attribute__ ((__packed__));
> struct unpacked_x { char c; cf f; };
> 
> Compile and compare the debug info; it does not respect __packed__.

This testcase has wrong debug info in 2.95.3 and
2.96-RH, but looks correct in 3.0 and 3.1:
        .ascii "f\0"    # DW_AT_name
        .byte   0x1     # DW_AT_decl_file
        .byte   0x2     # DW_AT_decl_line
        .long   0x4f    # DW_AT_type
        .byte   0x2     # DW_AT_data_member_location
        .byte   0x23    # DW_OP_plus_uconst
        .uleb128 0x1
^^^^^^^^^^^^^^^^^^^^
(this used to be 0x4 with older gcc's).

	Jakub