Subject: f77 -O causes optimizer to blow up (#81)
Index:	usr.bin/f77/{putdmr.c,dmrdefs} 2.11BSD

Description:
	Use of the -O switch with f77 causes the optimizer (/lib/c2)
	to die.

Repeat-By:
	Try using "f77 -O foo.f" with foo.f being approximately 400 lines
	long.  Observe the core dump of /lib/c2.

	The problem is that 'c2' optimizes blocks of code between ".globl"
	statements and f77 was not generating ".globl" statements between
	functions.  This was causing the generated code for the _entire_ Fortran
	program to appear as one block to be optimized.  Needless to say
	'c2' could not handle this except for trivial functions.

Fix:
	The fix is to cause f77 to generate ".globl name" (where "name" is
	the Fortran routine name being compiled.  Large functions will still
	be able to generate more code than 'c2' can handle (until such time
	as c2 is rewritten to use a workfile) but it will now be possible
	to turn on -O for many Fortran programs which previously caused
	the optimizer to crash.

	Also, the 'putc()' references were changed to 'fputc()' to save
	I space.  The 'fputc' function is currently implemented in pdp-11
	assembly, is almost as fast as the 'putc' macro and generates _far_
	less code.  Changing just the 5 references to 'putc' saved over
	500 bytes of code!  A few more space savings like that and the
	f77 compiler wouldn't have to be overlaid!

	A side effect of this fix is that after 'c2' optimizes the program
	the entry point to functions is at the top of the routine which
	makes debugging via 'adb' easier.

	Apply the patches below.  Recompile and install f77pass1.
	
	This and previous updates to 2.11BSD are available via anonymous
	FTP to FTP.IIPO.GTEGSC.COM in the directory /pub/2.11BSD.

=============================================================================
*** /usr/src/usr.bin/f77/putdmr.c.old	Mon Feb 16 16:57:40 1987
--- /usr/src/usr.bin/f77/putdmr.c	Thu Nov 12 21:57:38 1992
***************
*** 16,25 ****
  char *s;
  int class;
  {
  if( ! headerdone )
  	{
  	p2op2(P2SETREG, ARGREG-maxregvar);
! 	p2op(P2PROG);
  	headerdone = YES;
  #if TARGET == PDP11
  	/* fake jump to start the optimizer */
--- 16,40 ----
  char *s;
  int class;
  {
+ 
  if( ! headerdone )
  	{
  	p2op2(P2SETREG, ARGREG-maxregvar);
! 	p2op(P2PROG);	/* .text */
! /*
!  * 11/12/92, sms@192.26.147.1 
!  * The optimizer (/lib/c2) works on blocks of code delimited by .globl
!  * statements.  Without the addition below the fortran program ends up
!  * being one huge block which was causing the optimizer to blow up.  Large
!  * functions may still generate more code than /lib/c2 can handle, but for
!  * the most part it is now safe to use "f77 -O".
! */
! 	p2op(P2SYMDEF);	/* .globl */
! 	if (s)
! 		fprintf(textfile, "_%s", s);
! 	p2str("");
! /* end 11/12/92 change */
! 
  	headerdone = YES;
  #if TARGET == PDP11
  	/* fake jump to start the optimizer */
***************
*** 1198,1205 ****
  register char *s;
  s = &k;
  
! putc(*s++, textfile);
! putc(*s, textfile);
  }
  
  
--- 1213,1220 ----
  register char *s;
  s = &k;
  
! fputc(*s++, textfile);
! fputc(*s, textfile);
  }
  
  
***************
*** 1208,1215 ****
  p2op(op)
  int op;
  {
! putc(op, textfile);
! putc(0376, textfile);   /* MAGIC NUMBER */
  }
  
  
--- 1223,1230 ----
  p2op(op)
  int op;
  {
! fputc(op, textfile);
! fputc(0376, textfile);   /* MAGIC NUMBER */
  }
  
  
***************
*** 1219,1225 ****
  register char *s;
  {
  do
! 	putc(*s, textfile);
  		while(*s++);
  }
  
--- 1234,1240 ----
  register char *s;
  {
  do
! 	fputc(*s, textfile);
  		while(*s++);
  }
  
*** /usr/src/usr.bin/f77/dmrdefs.old	Sun Feb 22 00:46:20 1987
--- /usr/src/usr.bin/f77/dmrdefs	Thu Nov 12 20:46:44 1992
***************
*** 55,60 ****
--- 55,61 ----
  #define P2SETREG	105
  #define P2SETSTK	219
  #define P2PROG	202
+ #define	P2SYMDEF	207
  
  #define P2CHAR	1