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[Bug symtab/11479] New: Stabs qualified function argument with opaque type not dispalyed correctly


If a function is using qualified arguments with opaque types,
the size of this qualified type is not set correctly when the type
is resolved.
  This leads to garbage output with GDB.

Example code:
struct dummy;

void *
test (const struct dummy *t)
{
  struct dummy *tt;
  tt = t;
  return t;
}

void *
test2 (struct dummy *t)
{
  struct dummy *tt;
  tt = t;
  return t;
}


struct dummy {
 int x;
 int y;
 double b;
} tag_dummy;


int
main ()
{
  struct dummy tt;
  tt.x = 5;
  tt.y = 25;
  tt.b = 2.5;
  test2 (&tt);
  return test (&tt);
}

  gcc  -gstabs+ -o test test.c
gives the following output:

Pierre@d620-muller ~/gdbcvs/build-norm/gdb
$ gdb71.exe ./test
GNU gdb (GDB) 7.1
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-pc-cygwin".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/local/src/gdbcvs/build-norm/gdb/test.exe...done.
Setting up the environment for debugging gdb.
Function "internal_error" not defined.
Make breakpoint pending on future shared library load? (y or [n]) [answered N; i
nput not from terminal]
Function "info_command" not defined.
Make breakpoint pending on future shared library load? (y or [n]) [answered N; i
nput not from terminal]
/usr/local/src/gdbcvs/build-norm/gdb/.gdbinit:8: Error in sourced command file:
No breakpoint number 0.
(gdb) rb test
Breakpoint 1 at 0x401056: file test.c, line 8.
void *test(const struct dummy *);
Breakpoint 2 at 0x401067: file test.c, line 16.
void *test2(struct dummy *);
(gdb) r
Starting program: /usr/local/src/gdbcvs/build-norm/gdb/test.exe
[New Thread 5388.0x774]
[New Thread 5388.0x1438]

Breakpoint 2, test2 (t=0x22cc80) at test.c:16
16        tt = t;
(gdb) p *t
$1 = {x = 5, y = 25, b = 2.5}
(gdb) c
Continuing.

Breakpoint 1, test (t=0x22cc80) at test.c:8
8         tt = t;
(gdb) p *t
$2 = {x = 0, y = 0, b = 5.3049894774131808e-313}

Using 'set debug target 1' 
explains better what happens:

Breakpoint 2, test2 (t=0x22cc80) at test.c:16
16        tt = t;
(gdb) set debug target 1
(gdb) p *t
child:target_xfer_partial (2, (null), 0x1edea50, 0x0, 0x22cc50, 4) = 4, bytes =
 80 cc 22 00
child:target_xfer_partial (2, (null), 0x1ede9d0, 0x0, 0x22cc80, 16) = 16, bytes
=
 05 00 00 00 19 00 00 00 00 00 00 00 00 00 04 40
$5 = {x = 5, y = 25, b = 2.5}
(gdb) set debug target 0
(gdb) c
Continuing.

Breakpoint 1, test (t=0x22cc80) at test.c:8
8         tt = t;
(gdb) set debug target 1
(gdb) p *t
child:target_xfer_partial (2, (null), 0x202fc20, 0x0, 0x22cc50, 4) = 4, bytes =
 80 cc 22 00
$6 = {x = 0, y = 0, b = 4.0317920028340174e-313}
(gdb) p sizeof (*t)
$7 = 0

  If fact, the const qualifier in test function declaration
triggers the generation of a new structure type. 
This new type does not get its size set when the structure
is resolved.

  Tested both on windows and linux (32 bit generated code).

-- 
           Summary: Stabs qualified function argument with opaque type not
                    dispalyed correctly
           Product: gdb
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: symtab
        AssignedTo: unassigned at sourceware dot org
        ReportedBy: muller at ics dot u-strasbg dot fr
                CC: gdb-prs at sourceware dot org


http://sourceware.org/bugzilla/show_bug.cgi?id=11479

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