[perl #36852] [PATCH] imcc/main.c - to fix segmentation fault on "-E (--pre-process-only)" option

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Objective:
   Parrot stops for segmentation fault when "-E (--pre-process-only)"
option is specified.
   This patch fixes this bug.

Detail:
   The bug is following:

~/projects/parrot$ cat macro.pir
.macro hello(name)
        print "Hello,"
        print .name
        print "!\n"
.endm
.sub main
        .hello("world")
        .hello("Parrot")
.end
~/projects/parrot$ gdb --args ./parrot -E macro.pir
GNU gdb 6.3-debian
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-linux"...Using host libthread_db
library "/lib/libthread_db.so.1".

(gdb) run
Starting program: /home/tom/projects/parrot/parrot -E macro.pir
[Thread debugging using libthread_db enabled]
[New Thread 16384 (LWP 26420)]
[New Thread 32769 (LWP 26421)]
[New Thread 16386 (LWP 26422)]
[New Thread 32771 (LWP 26423)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 16384 (LWP 26420)]
0x0813ac12 in yylex (valp=0xbffffa50, interp=0x826fdc8) at imcc.l:122
122             if (frames->s.pasm_file && YYSTATE == INITIAL && !in_pod) {
(gdb) p frames
$1 = (struct macro_frame_t *) 0x0
(gdb) list
117             /* for emacs "*/
118             if (expect_pasm == 1 && !in_pod) {
119                 expect_pasm = 2;
120                 BEGIN(emit);
121             }
122             if (frames->s.pasm_file && YYSTATE == INITIAL && !in_pod) {
123                 if (0)
124                     yy_top_state(); /* silent warning */
125                 if (frames->s.pasm_file == 1) {
126                     BEGIN(emit);
(gdb) where
#0  0x0813ac12 in yylex (valp=0xbffffa50, interp=0x826fdc8) at imcc.l:122
#1  0x080847f6 in do_pre_process (interp=0x826fdc8) at imcc/main.c:371
#2  0x08084ef4 in main (argc=1, argv=0xbffffb0c) at imcc/main.c:502
(gdb) quit
The program is running.  Exit anyway? (y or n) y

   I guess that a variable "frames" in imcc/imclexer.c is prepared
before yylex() is called, likely attached patch.
   Frankly speaking, I don't understand imcc/imclexer.c much, so you can
probably take better ways than this patch...

--- imcc/main.c.orig	2005-08-10 10:31:31.000000000 +0900
+++ imcc/main.c	2005-08-10 10:55:00.000000000 +0900
@@ -368,6 +368,7 @@
     int c;
     YYSTYPE val;
 
+    IMCC_push_parser_state(interp);
     while ( (c = yylex(&val, interp)) ) {
         switch (c) {
             case EMIT:          printf(".emit\n"); break;