/* BFD back-end for mmo objects (MMIX-specific object-format).
- Copyright (C) 2001-2014 Free Software Foundation, Inc.
+ Copyright (C) 2001-2015 Free Software Foundation, Inc.
Written by Hans-Peter Nilsson (hp@bitrange.com).
Infrastructure and other bits originally copied from srec.c and
binary.c.
The mmo object format is used exclusively together with Professor
Donald E.@: Knuth's educational 64-bit processor MMIX. The simulator
@command{mmix} which is available at
- @url{http://www-cs-faculty.stanford.edu/~knuth/programs/mmix.tar.gz}
+ @url{http://mmix.cs.hm.edu/src/index.html}
understands this format. That package also includes a combined
assembler and linker called @command{mmixal}. The mmo format has
no advantages feature-wise compared to e.g. ELF. It is a simple
non-relocatable object format with no support for archives or
debugging information, except for symbol value information and
line numbers (which is not yet implemented in BFD). See
- @url{http://www-cs-faculty.stanford.edu/~knuth/mmix.html} for more
+ @url{http://mmix.cs.hm.edu/} for more
information about MMIX. The ELF format is used for intermediate
object files in the BFD implementation.
two remaining bytes, called the @samp{Y} and @samp{Z} fields, or
the @samp{YZ} field (a 16-bit big-endian number), are used for
various purposes different for each lopcode. As documented in
- @url{http://www-cs-faculty.stanford.edu/~knuth/mmixal-intro.ps.gz},
+ @url{http://mmix.cs.hm.edu/doc/mmixal.pdf},
the lopcodes are:
@table @code
directive, setting the location for the next data to the next
32-bit word (for @math{Z = 1}) or 64-bit word (for @math{Z = 2}),
plus @math{Y * 2^56}. Normally @samp{Y} is 0 for the text segment
- and 2 for the data segment.
+ and 2 for the data segment. Beware that the low bits of non-
+ tetrabyte-aligned values are silently discarded when being
+ automatically incremented and when storing contents (in contrast
+ to e.g. its use as current location when followed by lop_fixo
+ et al before the next possibly-quoted tetrabyte contents).
@item lop_skip
0x9802YYZZ. Increase the current location by @samp{YZ} bytes.
if (len)
{
+ /* We must have flushed a previous remainder if we get one from
+ this chunk too. */
+ BFD_ASSERT (mmop->byte_no == 0);
memcpy (mmop->buf, loc, len);
mmop->byte_no = len;
}
mmo_write_loc_chunk (bfd *abfd, bfd_vma vma, const bfd_byte *loc,
unsigned int len, bfd_vma *last_vmap)
{
- /* Find an initial and trailing section of zero tetras; we don't need to
- write out zeros. FIXME: When we do this, we should emit section size
- and address specifiers, else objcopy can't always perform an identity
- translation. Only do this if we *don't* have left-over data from a
- previous write or the vma of this chunk is *not* the next address,
- because then data isn't tetrabyte-aligned and we're concatenating to
- that left-over data. */
-
- if (abfd->tdata.mmo_data->byte_no == 0 || vma != *last_vmap)
+ /* Find an initial and trailing section of zero (aligned) tetras; we don't
+ need to write out zeros. FIXME: When we do this, we should emit
+ section size and address specifiers, else objcopy can't always perform
+ an identity translation. Only do this if we *don't* have left-over
+ data from a previous write (and will not add any) or else the vma of
+ this chunk is *not* the next address, because then data isn't
+ tetrabyte-aligned and we're concatenating to that left-over data. */
+
+ if ((vma & 3) == 0
+ && (abfd->tdata.mmo_data->byte_no == 0 || vma != *last_vmap))
{
- while (len >= 4 && bfd_get_32 (abfd, loc) == 0)
+ while (len > 4 && bfd_get_32 (abfd, loc) == 0)
{
vma += 4;
len -= 4;
loc += 4;
}
- while (len >= 4 && bfd_get_32 (abfd, loc + len - 4) == 0)
- len -= 4;
+ if ((len & 3) == 0)
+ while (len > 4 && bfd_get_32 (abfd, loc + len - 4) == 0)
+ len -= 4;
}
/* Only write out the location if it's different than the one the caller
/* We might be in the middle of a sequence. */
mmo_flush_chunk (abfd);
+ /* This should not happen during normal usage, but can presumably
+ happen with an erroneous linker-script, so handle gracefully.
+ Avoid Knuth-specific terms in the message, such as "tetrabyte".
+ Note that this function will get non-4-multiple lengths and
+ unaligned vmas but those come in tuples (mostly pairs) and are
+ continuous (i.e. the if-condition above false) and they are
+ group-wise aligned. */
+ if ((vma & 3) != 0)
+ {
+ (*_bfd_error_handler)
+ (_("%s: attempt to emit contents at non-multiple-of-4 address 0x%lx\n"),
+ bfd_get_filename (abfd), (unsigned long) vma);
+ bfd_set_error (bfd_error_bad_value);
+ return FALSE;
+ }
+
/* We always write the location as 64 bits; no use saving bytes
here. */
mmo_write_tetra_raw (abfd, (LOP << 24) | (LOP_LOC << 16) | 2);
SUBSECTION
Symbol table format
- From mmixal.w (or really, the generated mmixal.tex) in
- @url{http://www-cs-faculty.stanford.edu/~knuth/programs/mmix.tar.gz}):
+ From mmixal.w (or really, the generated mmixal.tex) in the
+ MMIXware package which also contains the @command{mmix} simulator:
``Symbols are stored and retrieved by means of a @samp{ternary
search trie}, following ideas of Bentley and Sedgewick. (See
ACM--SIAM Symp.@: on Discrete Algorithms @samp{8} (1997), 360--369;
if (bfd_bread (buf, 4, abfd) != 4)
goto error_return;
+ vma &= ~3;
mmo_xore_32 (sec, vma, bfd_get_32 (abfd, buf));
vma += 4;
- vma &= ~3;
lineno++;
break;
goto error_return;
}
- sec = mmo_decide_section (abfd, vma);
+ /* When we decide which section the data goes into, we might
+ create the section. If that happens, make sure the VMA at
+ creation time is tetra-aligned. */
+ sec = mmo_decide_section (abfd, vma & ~3);
if (sec == NULL)
goto error_return;
break;
count++;
}
- for (i = 0, serno = 1; i < count && table[i] != NULL; i++)
+ /* Don't bother inspecting symbols in plugin dummy objects; their
+ symbols aren't fully inspectable. */
+ if ((abfd->flags & BFD_PLUGIN) == 0)
{
- asymbol *s = table[i];
+ for (i = 0, serno = 1; i < count && table[i] != NULL; i++)
+ {
+ asymbol *s = table[i];
- /* It's not enough to consult bfd_is_local_label, since it does not
- mean "local" in the sense of linkable-and-observable-after-link.
- Let's just check the BSF_GLOBAL flag.
+ /* It's not enough to consult bfd_is_local_label, since it does not
+ mean "local" in the sense of linkable-and-observable-after-link.
+ Let's just check the BSF_GLOBAL flag.
- Also, don't export symbols with characters not in the allowed set. */
- if ((s->flags & (BSF_DEBUGGING|BSF_GLOBAL)) == BSF_GLOBAL
- && strspn (s->name,
- valid_mmo_symbol_character_set) == strlen (s->name))
- {
- struct mmo_symbol sym;
- memset (&sym, 0, sizeof (sym));
-
- /* Need to strip const here; strdup:ing would leak and the
- existing string must be safe to reuse. */
- sym.name = (char *) s->name;
- sym.value =
- s->value
- + s->section->output_section->vma
- + s->section->output_offset;
-
- if (bfd_is_und_section (s->section))
- sym.sym_type = mmo_undef_sym;
- else if (strcmp (s->section->name, MMO_DATA_SECTION_NAME) == 0
- /* The encoding of data symbols require that the "rest"
- of the value fits in 6 bytes, so the upper two bytes
- must be 0x2000. All other symbols get to be the
- absolute type. */
- && (sym.value >> 48) == 0x2000)
- sym.sym_type = mmo_data_sym;
- else if (strcmp (s->section->name, MMIX_REG_SECTION_NAME) == 0)
- sym.sym_type = mmo_reg_sym;
- else if (strcmp (s->section->name,
- MMIX_REG_CONTENTS_SECTION_NAME) == 0)
+ Also, don't export symbols with characters not in the
+ allowed set. */
+ if ((s->flags & (BSF_DEBUGGING|BSF_GLOBAL)) == BSF_GLOBAL
+ && strspn (s->name,
+ valid_mmo_symbol_character_set) == strlen (s->name))
{
- sym.sym_type = mmo_reg_sym;
- sym.value /= 8;
- }
- else
- sym.sym_type = mmo_abs_sym;
+ struct mmo_symbol sym;
+ memset (&sym, 0, sizeof (sym));
+
+ /* Need to strip const here; strdup:ing would leak and the
+ existing string must be safe to reuse. */
+ sym.name = (char *) s->name;
+ sym.value =
+ s->value
+ + s->section->output_section->vma
+ + s->section->output_offset;
+
+ if (bfd_is_und_section (s->section))
+ sym.sym_type = mmo_undef_sym;
+ else if (strcmp (s->section->name, MMO_DATA_SECTION_NAME) == 0
+ /* The encoding of data symbols require that the "rest"
+ of the value fits in 6 bytes, so the upper two bytes
+ must be 0x2000. All other symbols get to be the
+ absolute type. */
+ && (sym.value >> 48) == 0x2000)
+ sym.sym_type = mmo_data_sym;
+ else if (strcmp (s->section->name, MMIX_REG_SECTION_NAME) == 0)
+ sym.sym_type = mmo_reg_sym;
+ else if (strcmp (s->section->name,
+ MMIX_REG_CONTENTS_SECTION_NAME) == 0)
+ {
+ sym.sym_type = mmo_reg_sym;
+ sym.value /= 8;
+ }
+ else
+ sym.sym_type = mmo_abs_sym;
- /* FIXME: We assume the order of the received symbols is an
- ordered mapping of the serial numbers. This is not
- necessarily true if we e.g. objcopy a mmo file to another and
- there are gaps in the numbering. Not sure if this can
- happen. Not sure what to do. */
- sym.serno = serno++;
+ /* FIXME: We assume the order of the received symbols is an
+ ordered mapping of the serial numbers. This is not
+ necessarily true if we e.g. objcopy a mmo file to another and
+ there are gaps in the numbering. Not sure if this can
+ happen. Not sure what to do. */
+ sym.serno = serno++;
- if (! mmo_internal_add_3_sym (abfd, &root, &sym))
- return FALSE;
+ if (! mmo_internal_add_3_sym (abfd, &root, &sym))
+ return FALSE;
+ }
}
}
#define mmo_bfd_is_target_special_symbol \
((bfd_boolean (*) (bfd *, asymbol *)) bfd_false)
+#define mmo_get_symbol_version_string \
+ _bfd_nosymbols_get_symbol_version_string
+
/* Is this one really used or defined by anyone? */
#define mmo_get_lineno _bfd_nosymbols_get_lineno
/* FIXME: We can do better on this one, if we have a dwarf2 .debug_line
section or if MMO line numbers are implemented. */
#define mmo_find_nearest_line _bfd_nosymbols_find_nearest_line
+#define mmo_find_line _bfd_nosymbols_find_line
#define mmo_find_inliner_info _bfd_nosymbols_find_inliner_info
#define mmo_make_empty_symbol _bfd_generic_make_empty_symbol
#define mmo_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
#define mmo_bfd_gc_sections bfd_generic_gc_sections
#define mmo_bfd_lookup_section_flags bfd_generic_lookup_section_flags
#define mmo_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
-#define mmo_bfd_link_hash_table_free _bfd_generic_link_hash_table_free
#define mmo_bfd_link_add_symbols _bfd_generic_link_add_symbols
#define mmo_bfd_link_just_syms _bfd_generic_link_just_syms
#define mmo_bfd_copy_link_hash_symbol_type \
#define mmo_bfd_set_private_flags _bfd_generic_bfd_set_private_flags
#define mmo_bfd_print_private_bfd_data _bfd_generic_bfd_print_private_bfd_data
-const bfd_target bfd_mmo_vec =
+const bfd_target mmix_mmo_vec =
{
"mmo", /* name */
bfd_target_mmo_flavour,
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