MIPS glibc-2.3.2 build failure with gcc-3.4

MIPS glibc-2.3.2 build failure with gcc-3.4

[Michael Eager]

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I'm building glibc-2.3.2 for mips with the gcc-3.4-20040114 snapshot.

I'm getting an error building sigaction.c:
   ../sysdeps/unix/sysv/linux/mips/sigaction.c:83: error: $1 cannot be used in asm here

This code compiles using gcc-3.3.1.

The error is in global_alloc (global.c:355), in code which was added to 
fix PR 13169 (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169)

I've attached a cutdown version of sigaction.c.

Command line is "mips-gcc -O2 -c sigaction.c".

Suggestions?


--
Michael Eager     eager@mvista.com	408-328-8426	
MontaVista Software, Inc. 1237 E. Arques Ave., Sunnyvale, CA  94085

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extern int *__errno_location (void) __attribute__ ((__const__));

int
__libc_sigaction (sig, act, oact)
     int sig;
     int *act;
     int *oact;
{
  int result;
    {
      int kact, koact;
      if (act)
      result = (
	{ 
	  long err; 
	  long result_var = (
	    { 	
	     	long _sys_result; 
		{ 
		  register long __v0 asm("$2"); 
		  register long __a0 asm("$4") = (long) sig; 
		  register long __a1 asm("$5") = (long) act ? (&kact) : ((void *)0); 
		  register long __a2 asm("$6") = (long) oact ? (&koact) : ((void *)0); 
		  register long __a3 asm("$7") = (long) sizeof (int); 
		  __asm__ volatile ( 
			".set\tnoreorder\n\t" 
			"li\t$2, %5\t\t\t# "
			"rt_sigaction" "\n\t" 
			"syscall\n\t" 
			".set\treorder" 
			: "=r" (__v0), "+r" (__a3) 
			: "r" (__a0), "r" (__a1), "r" (__a2), "i" ((4000 + 194)) 
			: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24", "$25");
		   err = __a3;
		   _sys_result = __v0;
		   } _sys_result; 
		});
	      if ( ((long) (err)) ) 
		{ ((*__errno_location ()) = ((result_var))); 
		  result_var = -1L; 
	        } result_var; 
	});

 {
   return result;
 }
}
}

Re: MIPS glibc-2.3.2 build failure with gcc-3.4

[Eric Christopher]

On Wed, 2004-01-21 at 18:08, Michael Eager wrote:
> I'm building glibc-2.3.2 for mips with the gcc-3.4-20040114 snapshot.
> 
> I'm getting an error building sigaction.c:
>    ../sysdeps/unix/sysv/linux/mips/sigaction.c:83: error: $1 cannot be used in asm here
> 
> This code compiles using gcc-3.3.1.
> 
> The error is in global_alloc (global.c:355), in code which was added to 
> fix PR 13169 (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169)
> 
> I've attached a cutdown version of sigaction.c.
> 
> Command line is "mips-gcc -O2 -c sigaction.c".
> 
> Suggestions?

.set at

or don't use $1 there and actually use the instructions you want.

-eric

-- 
Eric Christopher <echristo@redhat.com>

Re: MIPS glibc-2.3.2 build failure with gcc-3.4

[Richard Sandiford]

Michael Eager <eager@mvista.com> writes:
> I'm building glibc-2.3.2 for mips with the gcc-3.4-20040114 snapshot.
>
> I'm getting an error building sigaction.c:
>    ../sysdeps/unix/sysv/linux/mips/sigaction.c:83: error: $1 cannot be used in asm here
>
> This code compiles using gcc-3.3.1.

This is a side-effect of a "cute" trick in the MIPS port.
Since it doesn't use $1 for anything, it reuses register 1 for
FRAME_POINTER_REGNUM.

I guess this was a good idea at one time (it reduced the number of hard
registers so could have reduced memory requirements or compile time).
But these days we have several hard registers that aren't being used for
anything.  We might as well use one of them as the frame pointer.

I've just tried the quick hack below and it seems to make
your test case pass.  I'll try to clean it up and test it later.

In the meantime, can you file a bug report for this so that
we don't lose track of it?  Thanks.

Richard


Index: config/mips/mips.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/mips/mips.c,v
retrieving revision 1.366
diff -u -p -F^\([(a-zA-Z0-9_]\|#define\) -r1.366 mips.c
--- config/mips/mips.c	20 Jan 2004 19:58:59 -0000	1.366
+++ config/mips/mips.c	22 Jan 2004 11:19:15 -0000
@@ -572,7 +572,7 @@ char mips_reg_names[][8] =
  "$f16", "$f17", "$f18", "$f19", "$f20", "$f21", "$f22", "$f23",
  "$f24", "$f25", "$f26", "$f27", "$f28", "$f29", "$f30", "$f31",
  "hi",   "lo",   "",     "$fcc0","$fcc1","$fcc2","$fcc3","$fcc4",
- "$fcc5","$fcc6","$fcc7","", "",     "",     "",     "$fakec",
+ "$fcc5","$fcc6","$fcc7","", "",     "",         "$frame", "$fakec",
  "$c0r0", "$c0r1", "$c0r2", "$c0r3", "$c0r4", "$c0r5", "$c0r6", "$c0r7",
  "$c0r8", "$c0r9", "$c0r10","$c0r11","$c0r12","$c0r13","$c0r14","$c0r15",
  "$c0r16","$c0r17","$c0r18","$c0r19","$c0r20","$c0r21","$c0r22","$c0r23",
@@ -601,7 +601,7 @@ char mips_sw_reg_names[][8] =
   "$f16", "$f17", "$f18", "$f19", "$f20", "$f21", "$f22", "$f23",
   "$f24", "$f25", "$f26", "$f27", "$f28", "$f29", "$f30", "$f31",
   "hi",   "lo",   "",     "$fcc0","$fcc1","$fcc2","$fcc3","$fcc4",
-  "$fcc5","$fcc6","$fcc7","$rap", "",     "",     "",     "$fakec",
+  "$fcc5","$fcc6","$fcc7","$rap", "",     "",     "$frame", "$fakec",
   "$c0r0", "$c0r1", "$c0r2", "$c0r3", "$c0r4", "$c0r5", "$c0r6", "$c0r7",
   "$c0r8", "$c0r9", "$c0r10","$c0r11","$c0r12","$c0r13","$c0r14","$c0r15",
   "$c0r16","$c0r17","$c0r18","$c0r19","$c0r20","$c0r21","$c0r22","$c0r23",
@@ -638,7 +638,7 @@ const enum reg_class mips_regno_to_class
   HI_REG,	LO_REG,		NO_REGS,	ST_REGS,
   ST_REGS,	ST_REGS,	ST_REGS,	ST_REGS,
   ST_REGS,	ST_REGS,	ST_REGS,	NO_REGS,
-  NO_REGS,	NO_REGS,	NO_REGS,	NO_REGS,
+  NO_REGS,	NO_REGS,	ALL_REGS,	NO_REGS,
   COP0_REGS,	COP0_REGS,	COP0_REGS,	COP0_REGS,
   COP0_REGS,	COP0_REGS,	COP0_REGS,	COP0_REGS,
   COP0_REGS,	COP0_REGS,	COP0_REGS,	COP0_REGS,
Index: config/mips/mips.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/mips/mips.h,v
retrieving revision 1.310
diff -u -p -F^\([(a-zA-Z0-9_]\|#define\) -r1.310 mips.h
--- config/mips/mips.h	7 Jan 2004 00:52:31 -0000	1.310
+++ config/mips/mips.h	22 Jan 2004 11:19:16 -0000
@@ -1665,7 +1665,7 @@ #define STACK_POINTER_REGNUM (GP_REG_FIR
    pretend that the frame pointer is $1, and then eliminate it to
    HARD_FRAME_POINTER_REGNUM.  We can get away with this because $1 is
    a fixed register, and will not be used for anything else.  */
-#define FRAME_POINTER_REGNUM (GP_REG_FIRST + 1)
+#define FRAME_POINTER_REGNUM 78
 
 /* $30 is not available on the mips16, so we use $17 as the frame
    pointer.  */

Re: MIPS glibc-2.3.2 build failure with gcc-3.4

[Richard Sandiford]

Richard Sandiford <rsandifo@redhat.com> writes:
> Since it doesn't use $1 for anything,

...in rtl, I mean.  Obviously some patterns will use $1 as a temporary
register internally.

Richard

Re: MIPS glibc-2.3.2 build failure with gcc-3.4

[Michael Eager]

Richard Sandiford wrote:
> Michael Eager <eager@mvista.com> writes:
> 
>>I'm building glibc-2.3.2 for mips with the gcc-3.4-20040114 snapshot.
>>
>>I'm getting an error building sigaction.c:
>>   ../sysdeps/unix/sysv/linux/mips/sigaction.c:83: error: $1 cannot be used in asm here
>>
>>This code compiles using gcc-3.3.1.
> 
> 
> This is a side-effect of a "cute" trick in the MIPS port.
> Since it doesn't use $1 for anything, it reuses register 1 for
> FRAME_POINTER_REGNUM.
> 
> I guess this was a good idea at one time (it reduced the number of hard
> registers so could have reduced memory requirements or compile time).
> But these days we have several hard registers that aren't being used for
> anything.  We might as well use one of them as the frame pointer.
> 
> I've just tried the quick hack below and it seems to make
> your test case pass.  I'll try to clean it up and test it later.

Yes, your patch fixes the problem.

> In the meantime, can you file a bug report for this so that
> we don't lose track of it?  Thanks.

Will do.



-- 
Michael Eager	 Eager Consulting     eager@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077