dbxout.c stabs output problem

[Ian Lance Taylor]

   Date: Tue, 14 Jul 1998 14:27:50 -0700
   From: Henry Sobotka <sobotka@axess.com>

   Compiled with -g -S, gcc 2.7 produces the following stabs for longlong:

   .stabs
   "longlong:t20=s8lo:3,0,32;hi:3,32,32;$_0::21=##22=*20;:__3$_0;2A.23=##22;:__3$_0RC3$_0;2A.;__as::24=##25=&20;:3$_0RC3$_0;2A.;;",128,0,3,0

   which can easily be parsed based on the info in the stabs manual. But
   with ecgs/pgcc (gcc 2.8 stabs) we get:

   .stabs
   "longlong:t24=s8lo:3,0,32;hi:3,32,32;__as::25=#24,26=&24,27=*24,28=&29=s8lo:3,0,32;hi:3,32,32;__as::25:__as__3$_0RC3$_0;2A.;$_0::30=#24,27,27,28,20;:__3$_0RC3$_0;2A.31=#24,27,27,20;:__3$_0;2A.;;,20;:__as__3$_0RC3$_0;2A.;$_0::30:__3$_0RC3$_0;2A.31:__3$_0;2A.;;",128,0,3,0

   Fed this stabs, emxomf breaks on the last 20 (in the ";;,20;:__as__"
   sequence) with an "invalid type for member function __as" message. t20
   here is the basic void type, i.e.

   .stabs "void:t20=20",128,0,0,0

   The front end is clearly doing a lot more with struct longlong than it
   did before.

I think the basic change is that g++ is now generating parameter
information for the automatically generated assignment and copy
constructors.  I'm not sure where emxomf is breaking down, but this
string can be parsed by gdb and by objdump --debugging.

This string is using two things which are not documented in
stabs.texinfo.  The single '#' stab ends at the next ';', not the next
'#' as stated by stabs.texinfo.  If a function described in this
manner is *not* a varargs function, then the last argument type will
be void.  This last is really a consequence of internal gcc argument
handling, and I tend to think that it is a bug that gcc outputs stabs
in this manner.

Here is the break down of your string:

longlong:			Name longlong defined as
 t24=				 type 24 defined as
  s8				  structure of size 8
  lo:3,0,32;			  field lo, type 3, bitpos 0, bitsize 32
  hi:3,32,32;			  field hi, type 3, bitpos 32, bitsize 32
  __as::			  member function __as of
   25=#				   type 25 defined as method
    24,				    class type 24 (the type being defined)
    26=&24,			    return type 26 = reference to 24
    27=*24,			    first argument 27 = pointer to 24
    28=&29=			    second argument 28 = reference to 29 =
     s8				      structure of size 8
     lo:3,0,32;			      field lo, type 3, bitpos 0, bitsize 32
     hi:3,32,32;		      field hi, type 3, bitpos 32, bitsize 32
     __as::25:			      member function __as of type 25
      __as__3$_0RC3$_0;		       real name $_0::operator=($_0 const &)
      2A.;			       public, non-const, non-virtual
     $_0::30=			      member function $_0 of type 30 =
      #24,			       method, class type 24
       27,			       return type 27
       27,			       first argument type 27
       28,			       second argment type 28
       20;			       void last argument means non-varargs
      :__3$_0RC3$_0;		       real name $_0::$_0($_0 const &)
      2A.			       public, non-const, non-virtual
      31=			      another member function $_0, type 31 =
       #24,			       method, class type 24
       27,			       return type 27
       27,			       first argument type 27
       20;			       void last argument means non-varargs
       :__3$_0;			       real name $_0::$_0(void)
       2A.;			       public, non-const, non-virtual
     ;				    end definition of type 28
   ,20;				    void last argument means non-varargs
   :__as__3$_0RC3$_0;		    real name $_0::operator=($_0 const &)
   2A.;				    public, non-const, non-virtual
  $_0::30:			  member function $_0 of type 30
   __3$_0RC3$_0;		   real name $_0::$_0($_0 const &)
   2A.				   public, non-const, non-virtual
   31:				  another member function $_0, type 31
    __3$_0;			   real name $_0::$_0(void)
    2A.;			   public, non-const, non-virtual
  ;				  end definition of type 24