Re: other/7114: ICE building strcoll.op from glibc-2.2.5

[Alan Modra <amodra@bigpond.net.au>]

The following reply was made to PR other/7114; it has been noted by GNATS.

From: Alan Modra <amodra@bigpond.net.au>
To: Geoff Keating <geoffk@redhat.com>
Cc: d.mueller@elsoft.ch, gcc-gnats@gcc.gnu.org, gcc-patches@gcc.gnu.org,
  dje@watson.ibm.com
Subject: Re: other/7114: ICE building strcoll.op from glibc-2.2.5
Date: Wed, 17 Jul 2002 18:30:49 +0930

 On Wed, Jul 17, 2002 at 12:07:11AM -0700, Geoff Keating wrote:
 > So, why don't we go back to the push/pop implementation, but this time
 > do it properly?  We'd only need to push/pop in the (rare)
 > nested-function case.
 
 I wasn't aware that powerpc used that scheme previously, and therefore
 was worried that some mcount implementation might peek at the stack.
 
 Here we go.
 
 	* config/rs6000/r6000.c (first_reg_to_save): Remove bogus
 	adjustments to first_reg for profiling case.
 	(output_function_profiler): Correct lr save slot for ABI_AIX_NODESC.
 	Disable profiling for 64 bit code on both ABI_V4 and ABI_AIX_NODESC.
 	Save static chain reg to sp + 12 on ABI_AIX_NODESC.
 	* config/rs6000/sysv4.h (ASM_OUTPUT_REG_PUSH): Define.
 	(ASM_OUTPUT_REG_POP): Define.
 	* config/rs6000/linux64.h (ASM_OUTPUT_REG_PUSH): Undef.
 	(ASM_OUTPUT_REG_POP): Undef.
 
 Rationale:
 
 	* config/rs6000/r6000.c (first_reg_to_save): Remove bogus
 	adjustments to first_reg for profiling case.
 first_reg_to_save doesn't need to do anything special for any of these
 registers as profiling is done via PROFILE_HOOK when ABI_AIX or
 ABI_DARWIN.  The normal register allocation code will set up
 regs_ever_live for us.  We're also not trying to use a reg when ABI_V4.
 
 	(output_function_profiler): Correct lr save slot for ABI_AIX_NODESC.
 ABI_AIX_NODESC saves lr to sp + 8.  This change is perhaps a little
 contentious as existing mcount implementations may take into account
 the current ABI breakage.
 
 	Disable profiling for 64 bit code on both ABI_V4 and ABI_AIX_NODESC.
 The instructions emitted here are 32 bit ones.  Fix this with a later
 patch.
 
 	Save static chain reg to sp + 12 on ABI_AIX_NODESC.
 We need to save it somewhere.  This seems a likely spot.
 
 	* config/rs6000/sysv4.h (ASM_OUTPUT_REG_PUSH): Define.
 	(ASM_OUTPUT_REG_POP): Define.
 Code resurrected from prior to Mon Mar 15 22:45:25 1999 delta, but
 with DEFAULT_ABI == ABI_V4 test added.
 
 
 powerpc-linux bootstrap on mainline seems to be broken at the moment.
 
 internal compiler error: Internal compiler error
  in tree_low_cst, at tree.c:3312
 
 so I'm in the process of bootstrapping this one on the 3.1 branch.
 
 -- 
 Alan Modra
 IBM OzLabs - Linux Technology Centre
 
 Index: gcc/config/rs6000/rs6000.c
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/config/rs6000/rs6000.c,v
 retrieving revision 1.344
 diff -u -p -r1.344 rs6000.c
 --- gcc/config/rs6000/rs6000.c	16 Jul 2002 20:59:03 -0000	1.344
 +++ gcc/config/rs6000/rs6000.c	17 Jul 2002 08:19:35 -0000
 @@ -7356,53 +7356,6 @@ first_reg_to_save ()
  		    || (DEFAULT_ABI == ABI_DARWIN && flag_pic)))))
        break;
  
 -  if (current_function_profile)
 -    {
 -      /* AIX must save/restore every register that contains a parameter
 -	 before/after the .__mcount call plus an additional register
 -	 for the static chain, if needed; use registers from 30 down to 22
 -	 to do this.  */
 -      if (DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_DARWIN)
 -	{
 -	  int last_parm_reg, profile_first_reg;
 -
 -	  /* Figure out last used parameter register.  The proper thing
 -	     to do is to walk incoming args of the function.  A function
 -	     might have live parameter registers even if it has no
 -	     incoming args.  */
 -	  for (last_parm_reg = 10;
 -	       last_parm_reg > 2 && ! regs_ever_live [last_parm_reg];
 -	       last_parm_reg--)
 -	    ;
 -
 -	  /* Calculate first reg for saving parameter registers
 -	     and static chain.
 -	     Skip reg 31 which may contain the frame pointer.  */
 -	  profile_first_reg = (33 - last_parm_reg
 -			       - (current_function_needs_context ? 1 : 0));
 -#if TARGET_MACHO
 -          /* Need to skip another reg to account for R31 being PICBASE
 -             (when flag_pic is set) or R30 being used as the frame
 -             pointer (when flag_pic is not set).  */
 -          --profile_first_reg;
 -#endif
 -	  /* Do not save frame pointer if no parameters needs to be saved.  */
 -	  if (profile_first_reg == 31)
 -	    profile_first_reg = 32;
 -
 -	  if (first_reg > profile_first_reg)
 -	    first_reg = profile_first_reg;
 -	}
 -
 -      /* SVR4 may need one register to preserve the static chain.  */
 -      else if (current_function_needs_context)
 -	{
 -	  /* Skip reg 31 which may contain the frame pointer.  */
 -	  if (first_reg > 30)
 -	    first_reg = 30;
 -	}
 -    }
 -
  #if TARGET_MACHO
    if (flag_pic && current_function_uses_pic_offset_table &&
        (first_reg > RS6000_PIC_OFFSET_TABLE_REGNUM))
 @@ -10429,6 +10382,7 @@ output_function_profiler (file, labelno)
    int labelno;
  {
    char buf[100];
 +  int save_lr = 8;
  
    ASM_GENERATE_INTERNAL_LABEL (buf, "LP", labelno);
    switch (DEFAULT_ABI)
 @@ -10437,13 +10391,21 @@ output_function_profiler (file, labelno)
        abort ();
  
      case ABI_V4:
 +      save_lr = 4;
 +      /* Fall through.  */
 +
      case ABI_AIX_NODESC:
 +      if (!TARGET_32BIT)
 +	{
 +	  warning ("no profiling of 64-bit code for this ABI");
 +	  return;
 +	}
        fprintf (file, "\tmflr %s\n", reg_names[0]);
        if (flag_pic == 1)
  	{
  	  fputs ("\tbl _GLOBAL_OFFSET_TABLE_@local-4\n", file);
 -	  asm_fprintf (file, "\t{st|stw} %s,4(%s)\n",
 -		       reg_names[0], reg_names[1]);
 +	  asm_fprintf (file, "\t{st|stw} %s,%d(%s)\n",
 +		       reg_names[0], save_lr, reg_names[1]);
  	  asm_fprintf (file, "\tmflr %s\n", reg_names[12]);
  	  asm_fprintf (file, "\t{l|lwz} %s,", reg_names[0]);
  	  assemble_name (file, buf);
 @@ -10451,8 +10413,8 @@ output_function_profiler (file, labelno)
  	}
        else if (flag_pic > 1)
  	{
 -	  asm_fprintf (file, "\t{st|stw} %s,4(%s)\n",
 -		       reg_names[0], reg_names[1]);
 +	  asm_fprintf (file, "\t{st|stw} %s,%d(%s)\n",
 +		       reg_names[0], save_lr, reg_names[1]);
  	  /* Now, we need to get the address of the label.  */
  	  fputs ("\tbl 1f\n\t.long ", file);
  	  assemble_name (file, buf);
 @@ -10468,27 +10430,32 @@ output_function_profiler (file, labelno)
  	  asm_fprintf (file, "\t{liu|lis} %s,", reg_names[12]);
  	  assemble_name (file, buf);
  	  fputs ("@ha\n", file);
 -	  asm_fprintf (file, "\t{st|stw} %s,4(%s)\n",
 -		       reg_names[0], reg_names[1]);
 +	  asm_fprintf (file, "\t{st|stw} %s,%d(%s)\n",
 +		       reg_names[0], save_lr, reg_names[1]);
  	  asm_fprintf (file, "\t{cal|la} %s,", reg_names[0]);
  	  assemble_name (file, buf);
  	  asm_fprintf (file, "@l(%s)\n", reg_names[12]);
  	}
  
 -      if (current_function_needs_context)
 -	asm_fprintf (file, "\tmr %s,%s\n",
 -		     reg_names[30], reg_names[STATIC_CHAIN_REGNUM]);
 -      fprintf (file, "\tbl %s\n", RS6000_MCOUNT);
 -      if (current_function_needs_context)
 -	asm_fprintf (file, "\tmr %s,%s\n",
 -		     reg_names[STATIC_CHAIN_REGNUM], reg_names[30]);
 +      if (current_function_needs_context && DEFAULT_ABI == ABI_AIX_NODESC)
 +	{
 +	  asm_fprintf (file, "\t{st|stw} %s,%d(%s)\n",
 +		       reg_names[STATIC_CHAIN_REGNUM],
 +		       12, reg_names[1]);
 +	  fprintf (file, "\tbl %s\n", RS6000_MCOUNT);
 +	  asm_fprintf (file, "\t{l|lwz} %s,%d(%s)\n",
 +		       reg_names[STATIC_CHAIN_REGNUM],
 +		       12, reg_names[1]);
 +	}
 +      else
 +	/* ABI_V4 saves the static chain reg with ASM_OUTPUT_REG_PUSH.  */
 +	fprintf (file, "\tbl %s\n", RS6000_MCOUNT);
        break;
  
      case ABI_AIX:
      case ABI_DARWIN:
        /* Don't do anything, done in output_profile_hook ().  */
        break;
 -
      }
  }
  
 Index: gcc/config/rs6000/sysv4.h
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/config/rs6000/sysv4.h,v
 retrieving revision 1.98
 diff -u -p -r1.98 sysv4.h
 --- gcc/config/rs6000/sysv4.h	10 Jul 2002 00:33:51 -0000	1.98
 +++ gcc/config/rs6000/sysv4.h	17 Jul 2002 08:19:36 -0000
 @@ -736,6 +736,38 @@ do {									\
    ASM_OUTPUT_ALIGNED_LOCAL (FILE, NAME, SIZE, ALIGN);			\
  } while (0)
  
 +/* This is how to output code to push a register on the stack.
 +   It need not be very fast code.
 +
 +   On the rs6000, we must keep the backchain up to date.  In order
 +   to simplify things, always allocate 16 bytes for a push (System V
 +   wants to keep stack aligned to a 16 byte boundary).  */
 +
 +#define	ASM_OUTPUT_REG_PUSH(FILE, REGNO)				\
 +do {									\
 +  if (DEFAULT_ABI == ABI_V4)						\
 +    asm_fprintf (FILE,							\
 +		 (TARGET_32BIT						\
 +		  ? "\t{stu|stwu} %s,-16(%s)\n\t{st|stw} %s,12(%s)\n"	\
 +		  : "\tstdu %s,-32(%s)\n\tstd %s,24(%s)\n"),		\
 +		 reg_names[1], reg_names[1], reg_names[REGNO],		\
 +		 reg_names[1]);						\
 +} while (0)
 +
 +/* This is how to output an insn to pop a register from the stack.
 +   It need not be very fast code.  */
 +
 +#define	ASM_OUTPUT_REG_POP(FILE, REGNO)					\
 +do {									\
 +  if (DEFAULT_ABI == ABI_V4)						\
 +    asm_fprintf (FILE,							\
 +		 (TARGET_32BIT						\
 +		  ? "\t{l|lwz} %s,12(%s)\n\t{ai|addic} %s,%s,16\n"	\
 +		  : "\tld %s,24(%s)\n\t{ai|addic} %s,%s,32\n"),		\
 +		 reg_names[REGNO], reg_names[1], reg_names[1],		\
 +		 reg_names[1]);						\
 +} while (0)
 +
  /* Switch  Recognition by gcc.c.  Add -G xx support.  */
  
  /* Override svr4.h definition.  */
 Index: gcc/config/rs6000/linux64.h
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/config/rs6000/linux64.h,v
 retrieving revision 1.21
 diff -u -p -r1.21 linux64.h
 --- gcc/config/rs6000/linux64.h	11 Jul 2002 00:23:16 -0000	1.21
 +++ gcc/config/rs6000/linux64.h	17 Jul 2002 08:19:25 -0000
 @@ -329,3 +329,7 @@ do									\
      sym_lineno += 1;							\
    }									\
  while (0)
 +
 +/* Override sysv4.h as these are ABI_V4 only.  */
 +#undef	ASM_OUTPUT_REG_PUSH
 +#undef	ASM_OUTPUT_REG_POP