java/1427: gcj should generate N_MAIN stab

java/1427: gcj should generate N_MAIN stab

[tromey]

>Number:         1427
>Category:       java
>Synopsis:       gcj should generate N_MAIN stab
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apbianco
>State:          analyzed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Dec 20 12:19:44 PST 2000
>Closed-Date:    
>Last-Modified:  Thu Apr 27 15:40:00 PDT 2000
>Originator:     Tom Tromey
>Release:        current cvs
>Organization:
>Environment:

>Description:
gcj should generate an N_MAIN stab which names
the "real" main function.  This will let gdb
present this to the user in an intelligent way,
so that users won't see the jvgenmain-generated
main() but will instead start the debug session
in their own code.
>How-To-Repeat:

>Fix:

>Release-Note:

>Audit-Trail:

Formerly PR gcj/49

State-Changed-From-To: open->analyzed
State-Changed-By: green
State-Changed-When: Sun Mar  5 09:39:50 2000
State-Changed-Why:
    I've submitted a patch for the GDB side of things.
    http://sourceware.cygnus.com/ml/gdb-patches/2000-q1/msg00527.html
    
    On the gcj side, all we really need to do is hack jvgenmain
    to emit:
    asm ( ".stabs \"myClass.main\", 0x2a, 0, 0, 0 " );
    ...at the top of the "main" source file.
    
    We should probably only do this on stabs systems.
    
    We will have to invent a DWARF2 way of doing this.  I
    don't think DWARF2 has anything like N_MAIN yet.

From: green@cygnus.com
To: apbianco@cygnus.com, java-gnats@sourceware.cygnus.com, jimb@cygnus.com,
  tromey@cygnus.com
Cc:  
Subject: Re: gcj/49
Date: 5 Mar 2000 17:39:50 -0000

 Synopsis: gcj should generate N_MAIN stab
 
 State-Changed-From-To: open->analyzed
 State-Changed-By: green
 State-Changed-When: Sun Mar  5 09:39:50 2000
 State-Changed-Why:
     I've submitted a patch for the GDB side of things.
     http://sourceware.cygnus.com/ml/gdb-patches/2000-q1/msg00527.html
     
     On the gcj side, all we really need to do is hack jvgenmain
     to emit:
     asm ( ".stabs \"myClass.main\", 0x2a, 0, 0, 0 " );
     ...at the top of the "main" source file.
     
     We should probably only do this on stabs systems.
     
     We will have to invent a DWARF2 way of doing this.  I
     don't think DWARF2 has anything like N_MAIN yet.
 
 http://sourceware.cygnus.com/cgi-bin/gnatsweb.pl?cmd=view&pr=49&database=java

From: Anthony Green <green@cygnus.com>
To: java-gnats@sourceware.cygnus.com, jimb@cygnus.com, apbianco@cygnus.com,
        tromey@cygnus.com
Cc:  
Subject: Re: gcj/49
Date: Sun, 23 Apr 2000 09:52:00 -0700

 I don't have a full patch for this yet. but this is very close.  All
 that's missing is a check to see whether or not we should actually
 emit it.  I think the compiler driver should pass this info down to
 jvgenmain.  Do any of you understand specs will enough to do this?
 
 Index: gcc/java/jvgenmain.c
 ===================================================================
 RCS file: /cvs/gcc/egcs/gcc/java/jvgenmain.c,v
 retrieving revision 1.15
 diff -c -r1.15 jvgenmain.c
 *** jvgenmain.c 2000/01/21 20:57:00 1.15
 --- jvgenmain.c 2000/04/23 16:45:03
 ***************
 *** 155,160 ****
 --- 155,165 ----
       }
     fprintf (stream, "  0\n};\n\n");
 
 +   /* Emit the N_MAIN stab.  */
 +   fprintf (stream, "asm ( \"/* Emit the N_MAIN stab identifying the
 program's `main'\n");
 +   fprintf (stream, "asm ( \".stabs \\\"%s.main\\\", 0x2a, 0, 0, 0 \"
 );\n\n",
 +     classname);
 +
     fprintf (stream, "extern struct Class %s%s;\n",
       class_mangling_prefix, mangled_classname);
     fprintf (stream, "int main (int argc, const char **argv)\n");
 
 
 http://sourceware.cygnus.com/cgi-bin/gnatsweb.pl?cmd=view&pr=49&database=java

From: Tom Tromey <tromey@cygnus.com>
To: green@cygnus.com
Cc: java-gnats@sourceware.cygnus.com, jimb@cygnus.com, apbianco@cygnus.com,
        tromey@cygnus.com
Subject: Re: gcj/49
Date: Sun, 23 Apr 2000 09:58:31 -0700 (PDT)

 Anthony> I don't have a full patch for this yet. but this is very
 Anthony> close.  All that's missing is a check to see whether or not
 Anthony> we should actually emit it.  I think the compiler driver
 Anthony> should pass this info down to jvgenmain.  Do any of you
 Anthony> understand specs will enough to do this?
 
 I could figure it out if I knew how to determine whether we need to
 emit this.  For instance, how do I know when the platform does not
 support stabs?  And how do I know whether or not it is needed?  Do I
 just check for -g?  (And how are we going to make this work with
 Dwarf?)
 
 Tom

From: Anthony Green <green@cygnus.com>
To: tromey@cygnus.com
Cc: java-gnats@sourceware.cygnus.com, jimb@cygnus.com, apbianco@cygnus.com,
        tromey@cygnus.com
Subject: Re: gcj/49
Date: Sun, 23 Apr 2000 10:09:14 -0700

 Tom wrote:
 > I could figure it out if I knew how to determine whether we need to
 > emit this.
 
 I think we only want to do it when `write_symbols == DBX_DEBUG' in
 toplev.c.  This probably doesn't help because we need to know in
 gcc.c.
 
 Jim - can gdb handle programs with both DWARF2 and STABS?  I think
 maybe it can.  
 
 In that case, maybe we just always emit it when any `-g' flag appears
 on the command line.
 
 > (And how are we going to make this work with Dwarf?)
 
 There's not dwarf way of doing it.  I think mixed stabs/dwarf will
 work for now.
 
 AG
 
 -- 
 Anthony Green                                                        Red Hat
                                                        Sunnyvale, California

From: Jim Blandy <jimb@zwingli.cygnus.com>
To: green@cygnus.com
Cc: tromey@cygnus.com, java-gnats@sourceware.cygnus.com, apbianco@cygnus.com
Subject: Re: gcj/49
Date: 27 Apr 2000 17:37:21 -0500

 > Jim - can gdb handle programs with both DWARF2 and STABS?  I think
 > maybe it can.  
 
 Yes, it can.
 
 > In that case, maybe we just always emit it when any `-g' flag appears
 > on the command line.
 
 Hmm.  Can every assembler handle the .stab pseudo-ops?
>Unformatted: