Re: [patch] Can't build ppc32 GDB

[Mark Kettenis <mark.kettenis@xs4all.nl>]

> From: PAUL GILLIAM <pgilliam@us.ibm.com>
> Date: Fri, 05 May 2006 11:32:18 -0700
> 
> OK, How about this?  I tried to make everyone happy :-)
> 
> Here is an excerpt:
> 
> #ifdef HAVE_STDINT_H
> #include <stdint.h>
> #define CORE_ADDR_CAST (uintptr_t)
> #else
> #define CORE_ADDR_CAST (CORE_ADDR)(unsigned long)
> #endif
> . . .
>   last_stopped_data_address = CORE_ADDR_CAST siginfo.si_addr;
> 
> Then when there is a gdb_stdint.h, I'll submit another patch to include
> it and replace CORE_ADDR_CAST with just (uintptr_t).
> 
> Ok to commit?

Sorry Paul, this is silly.  Just include <stdint.h> and use uintptr_t
unconditionally.  Or use unsigned long (the extra CORE_ADDR cast isn't
necessary) if you're really scared that someone will try to compile
GDB on a system with glibc 2.0.x.

Mark

> On Fri, 2006-05-05 at 18:49 +0200, Mark Kettenis wrote:
> > > Date: Fri, 5 May 2006 12:29:55 -0400
> > > From: Daniel Jacobowitz <drow@false.org>
> > > 
> > > On Thu, May 04, 2006 at 09:12:14AM +0200, Mark Kettenis wrote:
> > > > This is where the new ISO C99 <stdint.h> types come in handy.  Instead of
> > > > casting to CORE_ADDR, try casting to uintptr_t.
> > > 
> > > Can we rely on <stdint.h> on GNU/Linux?  I know we can't in general.
> > > Conveniently, I have a patch on one of my pending branches that
> > > provides a gdb_stdint.h.
> > 
> > Having a gdb_stdint.h would be cool ;-).
> > 
> > > But for this case there's an easier solution, which IIRC is roughly
> > > what Paul did: I can pretty much promise you that sizeof (long) ==
> > > sizeof (void *) on any GNU/Linux system.  So either I can merge
> > > gdb_stdint.h and we can start using that, which might be a nice idea in
> > > general, or for now I think "long" is fine.
> > 
> > Well, we already use uintptr_t in linux-thread-db.c, and
> > gdb_thread_db.h errors out if it isn't available (and has been doing
> > so for ages).  So we can be pretty sure that nobody is trying to
> > compile on systems with libc5 or really old glibc versions.
> > 
> > That said, it is probably safe to assume that all (powerpc) Linux
> > ports are either ILP32 or LP64, so casting to (unsigned long) should
> > be perfectly safe.  It's just that I think that a uintptr_t cast
> > better expresses what's happening here.  But either way is fine with
> > me.
> > 
> > Mark
> 
> --=-+yu21rc4iHrvNYe3G7+v
> Content-Disposition: attachment; filename=ppc-linux-nat.diff
> Content-Type: text/x-patch; name=ppc-linux-nat.diff; charset=utf-8
> Content-Transfer-Encoding: 7bit
> 
> 2006-04-26:  Paul Gilliam  <pgilliam@us.ibm.com>
> 
> 	* ppc-linux-nat.c: Clean up types for ptrace.
> 	New macro 'CORE_ADDR_CAST' accounts for the size difference between
> 	a CORE_ADDR and a void* on ppc64 systems compiled for 32-bits.
> 
> Index: ppc-linux-nat.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/ppc-linux-nat.c,v
> retrieving revision 1.60
> diff -a -u -r1.60 ppc-linux-nat.c
> --- ppc-linux-nat.c	24 Mar 2006 23:08:16 -0000	1.60
> +++ ppc-linux-nat.c	5 May 2006 18:15:28 -0000
> @@ -30,6 +30,13 @@
>  #include "target.h"
>  #include "linux-nat.h"
>  
> +#ifdef HAVE_STDINT_H
> +#include <stdint.h>
> +#define CORE_ADDR_CAST (uintptr_t)
> +#else
> +#define CORE_ADDR_CAST (CORE_ADDR)(unsigned long)
> +#endif
> +
>  #include <sys/types.h>
>  #include <sys/param.h>
>  #include <signal.h>
> @@ -44,18 +51,6 @@
>  #include "gregset.h"
>  #include "ppc-tdep.h"
>  
> -#ifndef PT_READ_U
> -#define PT_READ_U PTRACE_PEEKUSR
> -#endif
> -#ifndef PT_WRITE_U
> -#define PT_WRITE_U PTRACE_POKEUSR
> -#endif
> -
> -/* Default the type of the ptrace transfer to int.  */
> -#ifndef PTRACE_XFER_TYPE
> -#define PTRACE_XFER_TYPE int
> -#endif
> -
>  /* Glibc's headers don't define PTRACE_GETVRREGS so we cannot use a
>     configure time check.  Some older glibc's (for instance 2.2.1)
>     don't have a specific powerpc version of ptrace.h, and fall back on
> @@ -126,13 +121,12 @@
>  
>  /* On PPC processors that support the the Signal Processing Extension
>     (SPE) APU, the general-purpose registers are 64 bits long.
> -   However, the ordinary Linux kernel PTRACE_PEEKUSR / PTRACE_POKEUSR
> -   / PT_READ_U / PT_WRITE_U ptrace calls only access the lower half of
> -   each register, to allow them to behave the same way they do on
> -   non-SPE systems.  There's a separate pair of calls,
> -   PTRACE_GETEVRREGS / PTRACE_SETEVRREGS, that read and write the top
> -   halves of all the general-purpose registers at once, along with
> -   some SPE-specific registers.
> +   However, the ordinary Linux kernel PTRACE_PEEKUSER / PTRACE_POKEUSER
> +   ptrace calls only access the lower half of each register, to allow
> +   them to behave the same way they do on non-SPE systems.  There's a
> +   separate pair of calls, PTRACE_GETEVRREGS / PTRACE_SETEVRREGS, that
> +   read and write the top halves of all the general-purpose registers
> +   at once, along with some SPE-specific registers.
>  
>     GDB itself continues to claim the general-purpose registers are 32
>     bits long.  It has unnamed raw registers that hold the upper halves
> @@ -190,7 +184,7 @@
>    struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
>    /* NOTE: cagney/2003-11-25: This is the word size used by the ptrace
>       interface, and not the wordsize of the program's ABI.  */
> -  int wordsize = sizeof (PTRACE_XFER_TYPE);
> +  int wordsize = sizeof (long);
>  
>    /* General purpose registers occupy 1 slot each in the buffer */
>    if (regno >= tdep->ppc_gp0_regnum 
> @@ -384,17 +378,17 @@
>        return;
>      }
>  
> -  /* Read the raw register using PTRACE_XFER_TYPE sized chunks.  On a
> +  /* Read the raw register using sizeof(long) sized chunks.  On a
>       32-bit platform, 64-bit floating-point registers will require two
>       transfers.  */
>    for (bytes_transferred = 0;
>         bytes_transferred < register_size (current_gdbarch, regno);
> -       bytes_transferred += sizeof (PTRACE_XFER_TYPE))
> +       bytes_transferred += sizeof (long))
>      {
>        errno = 0;
> -      *(PTRACE_XFER_TYPE *) & buf[bytes_transferred]
> -        = ptrace (PT_READ_U, tid, (PTRACE_ARG3_TYPE) regaddr, 0);
> -      regaddr += sizeof (PTRACE_XFER_TYPE);
> +      *(long *) & buf[bytes_transferred]
> +        = ptrace (PTRACE_PEEKUSER, tid, (PTRACE_TYPE_ARG3) regaddr, 0);
> +      regaddr += sizeof (long);
>        if (errno != 0)
>  	{
>            char message[128];
> @@ -406,7 +400,7 @@
>  
>    /* Now supply the register.  Keep in mind that the regcache's idea
>       of the register's size may not be a multiple of sizeof
> -     (PTRACE_XFER_TYPE).  */
> +     (long).  */
>    if (gdbarch_byte_order (current_gdbarch) == BFD_ENDIAN_LITTLE)
>      {
>        /* Little-endian values are always found at the left end of the
> @@ -668,10 +662,10 @@
>  
>    /* First collect the register.  Keep in mind that the regcache's
>       idea of the register's size may not be a multiple of sizeof
> -     (PTRACE_XFER_TYPE).  */
> +     (long).  */
>    memset (buf, 0, sizeof buf);
>    bytes_to_transfer = align_up (register_size (current_gdbarch, regno),
> -                                sizeof (PTRACE_XFER_TYPE));
> +                                sizeof (long));
>    if (TARGET_BYTE_ORDER == BFD_ENDIAN_LITTLE)
>      {
>        /* Little-endian values always sit at the left end of the buffer.  */
> @@ -685,12 +679,12 @@
>        regcache_raw_collect (current_regcache, regno, buf + padding);
>      }
>  
> -  for (i = 0; i < bytes_to_transfer; i += sizeof (PTRACE_XFER_TYPE))
> +  for (i = 0; i < bytes_to_transfer; i += sizeof (long))
>      {
>        errno = 0;
> -      ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,
> -	      *(PTRACE_XFER_TYPE *) & buf[i]);
> -      regaddr += sizeof (PTRACE_XFER_TYPE);
> +      ptrace (PTRACE_POKEUSER, tid, (PTRACE_TYPE_ARG3) regaddr,
> +	      *(long *) & buf[i]);
> +      regaddr += sizeof (long);
>  
>        if (errno == EIO 
>            && regno == tdep->ppc_fpscr_regnum)
> @@ -901,7 +895,7 @@
>        (siginfo.si_code & 0xffff) != 0x0004)
>      return 0;
>  
> -  last_stopped_data_address = (CORE_ADDR) siginfo.si_addr;
> +  last_stopped_data_address = CORE_ADDR_CAST siginfo.si_addr;
>    return 1;
>  }
>  
> @@ -926,7 +920,7 @@
>  {
>    /* NOTE: cagney/2003-11-25: This is the word size used by the ptrace
>       interface, and not the wordsize of the program's ABI.  */
> -  int wordsize = sizeof (PTRACE_XFER_TYPE);
> +  int wordsize = sizeof (long);
>    ppc_linux_supply_gregset (current_regcache, -1, gregsetp,
>  			    sizeof (gdb_gregset_t), wordsize);
>  }
> @@ -936,7 +930,7 @@
>  {
>    /* NOTE: cagney/2003-11-25: This is the word size used by the ptrace
>       interface, and not the wordsize of the program's ABI.  */
> -  int wordsize = sizeof (PTRACE_XFER_TYPE);
> +  int wordsize = sizeof (long);
>    /* Right fill the register.  */
>    regcache_raw_collect (current_regcache, regnum,
>  			((bfd_byte *) reg
> 
> --=-+yu21rc4iHrvNYe3G7+v--
> 
>