Re: [PATCH] Fix jit.exp on most 32-bit targets.

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

> Date: Mon, 10 Oct 2011 22:58:47 -0400 (EDT)
> From: David Miller <davem@davemloft.net>
> 
> Outside of i386, most 32-bit targets align long long types on a 64-bit
> boundary.  But the JIT support code reading in the descriptor from the
> target just assumes that the size field will come right after the
> first three pointer sized fields.
> 
> This makes jit.exp fail.
> 
> Ok to commit?

Somehow this feels wrong to me.  But I guess it is too late to make
the JIT people change the design of their interface :(.

> 2011-10-10  David S. Miller  <davem@davemloft.net>
> 
> 	* gdbarch.sh: New field 'long_long_align_bit'.
> 	* gdbarch.c, gdbarch.h: Regenerate.
> 	* i386-tdep.c (i386_gdbarch_init): Set long_long_align_bit to 32.
> 	* jit.c (jit_read_code_entry): Use it to determine correct size offset.
> 
> diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
> index 2b892b6..ea48fa7 100644
> --- a/gdb/gdbarch.c
> +++ b/gdb/gdbarch.c
> @@ -145,6 +145,7 @@ struct gdbarch
>    int int_bit;
>    int long_bit;
>    int long_long_bit;
> +  int long_long_align_bit;
>    int half_bit;
>    const struct floatformat ** half_format;
>    int float_bit;
> @@ -299,6 +300,7 @@ struct gdbarch startup_gdbarch =
>    8 * sizeof (int),  /* int_bit */
>    8 * sizeof (long),  /* long_bit */
>    8 * sizeof (LONGEST),  /* long_long_bit */
> +  8 * sizeof (LONGEST),  /* long_long_align_bit */
>    16,  /* half_bit */
>    0,  /* half_format */
>    8 * sizeof (float),  /* float_bit */
> @@ -463,6 +465,7 @@ gdbarch_alloc (const struct gdbarch_info *info,
>    gdbarch->int_bit = 4*TARGET_CHAR_BIT;
>    gdbarch->long_bit = 4*TARGET_CHAR_BIT;
>    gdbarch->long_long_bit = 2*gdbarch->long_bit;
> +  gdbarch->long_long_align_bit = 2*gdbarch->long_bit;
>    gdbarch->half_bit = 2*TARGET_CHAR_BIT;
>    gdbarch->float_bit = 4*TARGET_CHAR_BIT;
>    gdbarch->double_bit = 8*TARGET_CHAR_BIT;
> @@ -576,6 +579,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
>    /* Skip verify of int_bit, invalid_p == 0 */
>    /* Skip verify of long_bit, invalid_p == 0 */
>    /* Skip verify of long_long_bit, invalid_p == 0 */
> +  /* Skip verify of long_long_align_bit, invalid_p == 0 */
>    /* Skip verify of half_bit, invalid_p == 0 */
>    if (gdbarch->half_format == 0)
>      gdbarch->half_format = floatformats_ieee_half;
> @@ -1020,6 +1024,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
>                        "gdbarch_dump: long_double_format = %s\n",
>                        pformat (gdbarch->long_double_format));
>    fprintf_unfiltered (file,
> +                      "gdbarch_dump: long_long_align_bit = %s\n",
> +                      plongest (gdbarch->long_long_align_bit));
> +  fprintf_unfiltered (file,
>                        "gdbarch_dump: long_long_bit = %s\n",
>                        plongest (gdbarch->long_long_bit));
>    fprintf_unfiltered (file,
> @@ -1424,6 +1431,23 @@ set_gdbarch_long_long_bit (struct gdbarch *gdbarch,
>  }
>  
>  int
> +gdbarch_long_long_align_bit (struct gdbarch *gdbarch)
> +{
> +  gdb_assert (gdbarch != NULL);
> +  /* Skip verify of long_long_align_bit, invalid_p == 0 */
> +  if (gdbarch_debug >= 2)
> +    fprintf_unfiltered (gdb_stdlog, "gdbarch_long_long_align_bit called\n");
> +  return gdbarch->long_long_align_bit;
> +}
> +
> +void
> +set_gdbarch_long_long_align_bit (struct gdbarch *gdbarch,
> +                                 int long_long_align_bit)
> +{
> +  gdbarch->long_long_align_bit = long_long_align_bit;
> +}
> +
> +int
>  gdbarch_half_bit (struct gdbarch *gdbarch)
>  {
>    gdb_assert (gdbarch != NULL);
> diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
> index 0117322..d8420cc 100644
> --- a/gdb/gdbarch.h
> +++ b/gdb/gdbarch.h
> @@ -120,6 +120,12 @@ extern void set_gdbarch_long_bit (struct gdbarch *gdbarch, int long_bit);
>  extern int gdbarch_long_long_bit (struct gdbarch *gdbarch);
>  extern void set_gdbarch_long_long_bit (struct gdbarch *gdbarch, int long_long_bit);
>  
> +/* Alignment of a long long or unsigned long long for the target
> +   machine. */
> +
> +extern int gdbarch_long_long_align_bit (struct gdbarch *gdbarch);
> +extern void set_gdbarch_long_long_align_bit (struct gdbarch *gdbarch, int long_long_align_bit);
> +
>  /* The ABI default bit-size and format for "half", "float", "double", and
>     "long double".  These bit/format pairs should eventually be combined
>     into a single object.  For the moment, just initialize them as a pair.
> @@ -586,7 +592,7 @@ extern void set_gdbarch_smash_text_address (struct gdbarch *gdbarch, gdbarch_sma
>     FIXME/cagney/2001-01-18: The logic is backwards.  It should be asking if the
>     target can single step.  If not, then implement single step using breakpoints.
>    
> -   A return value of 1 means that the software_single_step breakpoints
> +   A return value of 1 means that the software_single_step breakpoints 
>     were inserted; 0 means they were not. */
>  
>  extern int gdbarch_software_single_step_p (struct gdbarch *gdbarch);
> diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
> index dcf0343..bf78173 100755
> --- a/gdb/gdbarch.sh
> +++ b/gdb/gdbarch.sh
> @@ -362,6 +362,9 @@ v:int:long_bit:::8 * sizeof (long):4*TARGET_CHAR_BIT::0
>  # Number of bits in a long long or unsigned long long for the target
>  # machine.
>  v:int:long_long_bit:::8 * sizeof (LONGEST):2*gdbarch->long_bit::0
> +# Alignment of a long long or unsigned long long for the target
> +# machine.
> +v:int:long_long_align_bit:::8 * sizeof (LONGEST):2*gdbarch->long_bit::0
>  
>  # The ABI default bit-size and format for "half", "float", "double", and
>  # "long double".  These bit/format pairs should eventually be combined
> diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
> index 179bc45..2f0b6f5 100644
> --- a/gdb/i386-tdep.c
> +++ b/gdb/i386-tdep.c
> @@ -7281,6 +7281,8 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>  
>    tdep->record_regmap = i386_record_regmap;
>  
> +  set_gdbarch_long_long_align_bit (gdbarch, 32);
> +
>    /* The format used for `long double' on almost all i386 targets is
>       the i387 extended floating-point format.  In fact, of all targets
>       in the GCC 2.95 tree, only OSF/1 does it different, and insists
> diff --git a/gdb/jit.c b/gdb/jit.c
> index eb1bcc7..283ccdb 100644
> --- a/gdb/jit.c
> +++ b/gdb/jit.c
> @@ -205,10 +205,11 @@ static void
>  jit_read_code_entry (struct gdbarch *gdbarch,
>  		     CORE_ADDR code_addr, struct jit_code_entry *code_entry)
>  {
> -  int err;
> +  int err, off;
>    struct type *ptr_type;
>    int ptr_size;
>    int entry_size;
> +  int align_bytes;
>    gdb_byte *entry_buf;
>    enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
>  
> @@ -230,8 +231,13 @@ jit_read_code_entry (struct gdbarch *gdbarch,
>        extract_typed_address (&entry_buf[ptr_size], ptr_type);
>    code_entry->symfile_addr =
>        extract_typed_address (&entry_buf[2 * ptr_size], ptr_type);
> +
> +  align_bytes = gdbarch_long_long_align_bit (gdbarch) / 8;
> +  off = 3 * ptr_size;
> +  off = (off + (align_bytes - 1)) & ~(align_bytes - 1);
> +
>    code_entry->symfile_size =
> -      extract_unsigned_integer (&entry_buf[3 * ptr_size], 8, byte_order);
> +      extract_unsigned_integer (&entry_buf[off], 8, byte_order);
>  }
>  
>  /* This function registers code associated with a JIT code entry.  It uses the
>