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1999-09-13 Donn Terry <donn@interix.com>

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* coffcode.h (styp_to_sec_flags): Further refinement of COMDAT
	handling to support both GNU and MS objects.
This commit is contained in:
Ian Lance Taylor 1999-09-13 23:55:22 +00:00
parent 361d94e768
commit e5db213db2
2 changed files with 178 additions and 91 deletions
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3
bfd/ChangeLog
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@ -1,5 +1,8 @@
1999-09-13 Donn Terry <donn@interix.com>
* coffcode.h (styp_to_sec_flags): Further refinement of COMDAT
handling to support both GNU and MS objects.
* coffcode.h (coff_write_object_contents): Don't check reloc_count
when determining whether to set F_RELFLG.

266
bfd/coffcode.h
View File

@ -759,6 +759,8 @@ styp_to_sec_flags (abfd, hdr, name, section)
if (_bfd_coff_get_external_symbols (abfd))
{
bfd_byte *esymstart, *esym, *esymend;
int seen_state = 0;
char *target_name;
esymstart = esym = (bfd_byte *) obj_coff_external_syms (abfd);
esymend = esym + obj_raw_syment_count (abfd) * SYMESZ;
@ -778,122 +780,204 @@ styp_to_sec_flags (abfd, hdr, name, section)
abort ();
}
/* The MS documentation is vague, but it appears to
require that n_sclass be C_STAT for both entries;
However, the Alpha compiler uses C_EXT for the one
with the "real" name, at least for string-pooled
constants. */
if (isym.n_scnum == section->target_index
&& (isym.n_sclass == C_STAT || isym.n_sclass == C_EXT)
&& isym.n_type == T_NULL
&& isym.n_value == 0)
if (isym.n_scnum == section->target_index)
{
/* The first TWO entries with the section # are both
of interest to us. The first one is the "section
/* According to the MSVC documentation, the first
TWO entries with the section # are both of
interest to us. The first one is the "section
symbol" (section name). The second is the comdat
symbol name. 'value' must be zero for it to
apply. Here, we've found a qualifying entry; we
distinguish the first from the second by numaux
(which should be 0 for the second). FIXME: We
should use the first one first rather than
counting on numaux. */
if (isym.n_numaux == 1)
symbol name. Here, we've found the first
qualifying entry; we distinguish it from the
second with a state flag.
In the case of gas-generated (at least until that
is fixed) .o files, it isn't necessarily the
second one. It may be some other later symbol.
Since gas also doesn't follow MS conventions and
emits the section similar to .text$<name>, where
<something> is the name we're looking for, we
distinguish the two as follows:
If the section name is simply a section name (no
$) we presume it's MS-generated, and look at
precisely the second symbol for the comdat name.
If the section name has a $, we assume it's
gas-generated, and look for <something> (whatever
follows the $) as the comdat symbol. */
/* All 3 branches use this */
symname = _bfd_coff_internal_syment_name (abfd, &isym, buf);
if (symname == NULL)
abort ();
switch (seen_state)
{
union internal_auxent aux;
case 0:
{
/* The first time we've seen the symbol. */
union internal_auxent aux;
symname = _bfd_coff_internal_syment_name (abfd, &isym,
buf);
if (symname == NULL)
abort ();
seen_state = 1;
if (strcmp (name, symname) != 0)
abort ();
/* If it isn't the stuff we're expecting, die;
The MS documentation is vague, but it
appears that the second entry serves BOTH
as the comdat symbol and the defining
symbol record (either C_STAT or C_EXT,
possibly with an aux entry with debug
information if it's a function.) It
appears the only way to find the second one
is to count. (On Intel, they appear to be
adjacent, but on Alpha, they have been
found separated.)
/* This is the section symbol. */
Here, we think we've found the first one,
but there's some checking we can do to be
sure. */
bfd_coff_swap_aux_in (abfd, (PTR) (esym + SYMESZ),
isym.n_type, isym.n_sclass,
0, isym.n_numaux, (PTR) &aux);
if (! (isym.n_sclass == C_STAT
&& isym.n_type == T_NULL
&& isym.n_value == 0))
abort ();
/* FIXME: Microsoft uses NODUPLICATES and
ASSOCIATIVE, but gnu uses ANY and SAME_SIZE.
Unfortunately, gnu doesn't do the comdat
symbols right. So, until we can fix it to do
the right thing, we are temporarily disabling
comdats for the MS types (they're used in
DLLs and C++, but we don't support *their*
C++ libraries anyway - DJ. */
/* FIXME LATER: MSVC generates section names
like .text for comdats. Gas generates
names like .text$foo__Fv (in the case of a
function). See comment above for more. */
switch (aux.x_scn.x_comdat)
{
case IMAGE_COMDAT_SELECT_NODUPLICATES:
#ifdef STRICT_PE_FORMAT
sec_flags |= SEC_LINK_DUPLICATES_ONE_ONLY;
if (strcmp (name, symname) != 0)
abort ();
/* This is the section symbol. */
bfd_coff_swap_aux_in (abfd, (PTR) (esym + SYMESZ),
isym.n_type, isym.n_sclass,
0, isym.n_numaux, (PTR) &aux);
target_name = strchr (name, '$');
if (target_name != NULL)
{
/* Gas mode. */
seen_state = 2;
/* Skip the `$'. */
target_name += 1;
}
/* FIXME: Microsoft uses NODUPLICATES and
ASSOCIATIVE, but gnu uses ANY and
SAME_SIZE. Unfortunately, gnu doesn't do
the comdat symbols right. So, until we can
fix it to do the right thing, we are
temporarily disabling comdats for the MS
types (they're used in DLLs and C++, but we
don't support *their* C++ libraries anyway
- DJ. */
/* Cygwin does not follow the MS style, and
uses ANY and SAME_SIZE where NODUPLICATES
and ASSOCIATIVE should be used. For
Interix, we just do the right thing up
front. */
switch (aux.x_scn.x_comdat)
{
case IMAGE_COMDAT_SELECT_NODUPLICATES:
#ifdef STRICT_PE_FORMAT
sec_flags |= SEC_LINK_DUPLICATES_ONE_ONLY;
#else
sec_flags &= ~SEC_LINK_ONCE;
sec_flags &= ~SEC_LINK_ONCE;
#endif
break;
break;
case IMAGE_COMDAT_SELECT_ANY:
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
break;
case IMAGE_COMDAT_SELECT_ANY:
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
break;
case IMAGE_COMDAT_SELECT_SAME_SIZE:
sec_flags |= SEC_LINK_DUPLICATES_SAME_SIZE;
break;
case IMAGE_COMDAT_SELECT_SAME_SIZE:
sec_flags |= SEC_LINK_DUPLICATES_SAME_SIZE;
break;
case IMAGE_COMDAT_SELECT_EXACT_MATCH:
/* Not yet fully implemented in the linker. */
sec_flags |= SEC_LINK_DUPLICATES_SAME_CONTENTS;
break;
case IMAGE_COMDAT_SELECT_EXACT_MATCH:
/* Not yet fully implemented ??? */
sec_flags |= SEC_LINK_DUPLICATES_SAME_CONTENTS;
break;
case IMAGE_COMDAT_SELECT_ASSOCIATIVE:
/* debug$S gets this case; other
implications ??? */
/* There may be no symbol... we'll search
the whole table... Is this the right
place to play this game? Or should we do
it when reading it in. */
case IMAGE_COMDAT_SELECT_ASSOCIATIVE:
#ifdef STRICT_PE_FORMAT
/* FIXME: This is not currently implemented. */
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
/* FIXME: This is not currently implemented. */
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
#else
sec_flags &= ~SEC_LINK_ONCE;
sec_flags &= ~SEC_LINK_ONCE;
#endif
break;
default:
/* FIXME: Shouldn't this be at least a
warning? */
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
break;
}
}
else
{
char *newname;
/* This should be the the second symbol with the
section #. It is the actual symbol name.
Intel puts the two adjacent, but Alpha (at
least) spreads them out. */
section->comdat =
bfd_alloc (abfd, sizeof (struct bfd_comdat_info));
if (section->comdat == NULL)
abort ();
section->comdat->symbol = (esym - esymstart) / SYMESZ;
symname = _bfd_coff_internal_syment_name (abfd, &isym,
buf);
if (symname == NULL)
abort ();
newname = bfd_alloc (abfd, strlen (symname) + 1);
if (newname == NULL)
abort ();
strcpy (newname, symname);
section->comdat->name = newname;
break;
default: /* 0 means "no symbol" */
/* debug$F gets this case; other
implications ??? */
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
break;
}
}
break;
case 2:
/* Gas mode: the first matching on partial name. */
#ifndef TARGET_UNDERSCORE
#define TARGET_UNDERSCORE 0
#endif
/* Is this the name we're looking for? */
if (strcmp (target_name,
symname + (TARGET_UNDERSCORE ? 1 : 0)) != 0)
{
/* Not the name we're looking for */
esym += (isym.n_numaux + 1) * SYMESZ;
continue;
}
/* Fall through. */
case 1:
/* MSVC mode: the lexically second symbol (or
drop through from the above). */
{
char *newname;
/* This must the the second symbol with the
section #. It is the actual symbol name.
Intel puts the two adjacent, but Alpha (at
least) spreads them out. */
section->comdat =
bfd_alloc (abfd, sizeof (struct bfd_comdat_info));
if (section->comdat == NULL)
abort ();
section->comdat->symbol =
(esym - esymstart) / SYMESZ;
newname = bfd_alloc (abfd, strlen (symname) + 1);
if (newname == NULL)
abort ();
strcpy (newname, symname);
section->comdat->name = newname;
}
goto breakloop;
}
}
esym += (isym.n_numaux + 1) * SYMESZ;
}
breakloop:
}
}