[Bug ada/49084] [4.7 regression] bootstrap failure with Ada enabled

["cestrauss at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49084

--- Comment #11 from Cesar Strauss <cestrauss at gmail dot com> 2011-11-27 20:55:15 UTC ---
Created attachment 25922
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25922
Debug log of PR49084

The cause of the access violation is due to an attempt to pass a null string
pointer to asprintf in internal_error_function
(gcc/ada/gcc-interface/misc.c:290):

(gdb) frame 2
#2  0x0042bfad in internal_error_function (context=0x1a15800, msgid=0x11e08df
"in %s, at %s:%d", ap=0x722faa4) at
../../../../gcc-svn-fixada/gcc/ada/gcc-interface/misc.c:290
290         asprintf (&loc, "%s:%d", s.file, s.line);

(gdb) l
286       s = expand_location (input_location);
287       if (context->show_column && s.column != 0)
288         asprintf (&loc, "%s:%d:%d", s.file, s.line, s.column);
289       else
290         asprintf (&loc, "%s:%d", s.file, s.line);
291       temp_loc.Low_Bound = 1;
292       temp_loc.High_Bound = strlen (loc);
293       fp_loc.Bounds = &temp_loc;
294       fp_loc.Array = loc;

(gdb) p input_location
$1 = 0

(gdb) p s
$2 = {file = 0x0, line = 0, column = 0, sysp = <optimized out>}

It remains to be seen why input_location is zero. Maybe it's too early in the
process execution?

Earlier in the stack trace, there is an assertion triggered in gigi
(ada/gcc-interface/trans.c:300):

(gdb) fr 6
#6  0x00491875 in gigi (gnat_root=1707, max_gnat_node=2431, number_name=1656,
nodes_ptr=0x7950020, next_node_ptr=0x78b52f8, prev_node_ptr=0x78e6050,
elists_ptr=0x7708e78, elmts_ptr=0x77094d0, strings_ptr=0x7734818,
string_chars_ptr=0x77320f0, list_headers_ptr=0x78a9760, number_file=3,
file_info_ptr=0x722fb9c, standard_boolean=12, standard_integer=27,
standard_character=72, standard_long_long_float=67,
standard_exception_type=1281, gigi_operating_mode=0) at
../../../../gcc-svn-fixada/gcc/ada/gcc-interface/trans.c:300
300       gcc_assert (Nkind (gnat_root) == N_Compilation_Unit);

(gdb) l
295       String_Chars_Ptr = string_chars_ptr;
296       List_Headers_Ptr = list_headers_ptr;
297
298       type_annotate_only = (gigi_operating_mode == 1);
299
300       gcc_assert (Nkind (gnat_root) == N_Compilation_Unit);
301
302       /* Declare the name of the compilation unit as the first global
303          name in order to make the middle-end fully deterministic.  */
304       t = create_concat_name (Defining_Entity (Unit (gnat_root)), NULL);

(gdb) p gnat_root
$3 = 1707

(gdb) p (Nodes_Ptr[(gnat_root) - 0].U.K.kind)
$4 = 17 '\021'

It seems Nkind (gnat_root) is N_Op_Add (17) for some reason.

BTW this is trunk (svn 181738), with the stage 2 compiler (this bug is not
manifest in the stage 1 compiler).

Full debug log is attached.