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BFD: Catch & report unhandled PE section flags.

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LD: Catch BFD errors whilst loading symbols and do not produce an executable.
This commit is contained in:
Nick Clifton
2001-02-27 01:38:06 +00:00
parent fa7cd6d20a
commit 1276aefac0
7 changed files with 790 additions and 643 deletions
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654
bfd/coffcode.h
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@@ -339,6 +339,9 @@ static long coff_canonicalize_reloc
#ifndef coff_mkobject_hook
static PTR coff_mkobject_hook PARAMS ((bfd *, PTR, PTR));
#endif
#ifdef COFF_WITH_PE
static flagword handle_COMDAT PARAMS ((bfd *, flagword, PTR, const char *, asection *));
#endif
/* void warning(); */
@@ -698,6 +701,261 @@ styp_to_sec_flags (abfd, hdr, name, section)
#else /* COFF_WITH_PE */
static flagword
handle_COMDAT (abfd, sec_flags, hdr, name, section)
bfd * abfd;
flagword sec_flags;
PTR hdr;
const char *name;
asection *section;
{
struct internal_scnhdr *internal_s = (struct internal_scnhdr *) hdr;
bfd_byte *esymstart, *esym, *esymend;
int seen_state = 0;
char *target_name = NULL;
sec_flags |= SEC_LINK_ONCE;
/* Unfortunately, the PE format stores essential information in
the symbol table, of all places. We need to extract that
information now, so that objdump and the linker will know how
to handle the section without worrying about the symbols. We
can't call slurp_symtab, because the linker doesn't want the
swapped symbols. */
/* COMDAT sections are special. The first symbol is the section
symbol, which tells what kind of COMDAT section it is. The
second symbol is the "comdat symbol" - the one with the
unique name. GNU uses the section symbol for the unique
name; MS uses ".text" for every comdat section. Sigh. - DJ */
/* This is not mirrored in sec_to_styp_flags(), but there
doesn't seem to be a need to, either, and it would at best be
rather messy. */
if (! _bfd_coff_get_external_symbols (abfd))
return sec_flags;
esymstart = esym = (bfd_byte *) obj_coff_external_syms (abfd);
esymend = esym + obj_raw_syment_count (abfd) * bfd_coff_symesz (abfd);
while (esym < esymend)
{
struct internal_syment isym;
char buf[SYMNMLEN + 1];
const char *symname;
bfd_coff_swap_sym_in (abfd, (PTR) esym, (PTR) &isym);
if (sizeof (internal_s->s_name) > SYMNMLEN)
{
/* This case implies that the matching
symbol name will be in the string table. */
abort ();
}
if (isym.n_scnum == section->target_index)
{
/* 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. 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 $) as the comdat symbol. */
/* All 3 branches use this */
symname = _bfd_coff_internal_syment_name (abfd, &isym, buf);
if (symname == NULL)
abort ();
switch (seen_state)
{
case 0:
{
/* The first time we've seen the symbol. */
union internal_auxent aux;
seen_state = 1;
/* If it isn't the stuff we're expecting, die;
The MS documentation is vague, but it
appears that the second entry serves BOTH
as the comdat symbol and the defining
symbol record (either C_STAT or C_EXT,
possibly with an aux entry with debug
information if it's a function.) It
appears the only way to find the second one
is to count. (On Intel, they appear to be
adjacent, but on Alpha, they have been
found separated.)
Here, we think we've found the first one,
but there's some checking we can do to be
sure. */
if (! (isym.n_sclass == C_STAT
&& isym.n_type == T_NULL
&& isym.n_value == 0))
abort ();
/* FIXME LATER: MSVC generates section names
like .text for comdats. Gas generates
names like .text$foo__Fv (in the case of a
function). See comment above for more. */
if (strcmp (name, symname) != 0)
abort ();
/* This is the section symbol. */
bfd_coff_swap_aux_in (abfd, (PTR) (esym + bfd_coff_symesz (abfd)),
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;
#endif
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_EXACT_MATCH:
/* Not yet fully implemented ??? */
sec_flags |= SEC_LINK_DUPLICATES_SAME_CONTENTS;
break;
/* debug$S gets this case; other
implications ??? */
/* There may be no symbol... we'll search
the whole table... Is this the right
place to play this game? Or should we do
it when reading it in. */
case IMAGE_COMDAT_SELECT_ASSOCIATIVE:
#ifdef STRICT_PE_FORMAT
/* FIXME: This is not currently implemented. */
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
#else
sec_flags &= ~SEC_LINK_ONCE;
#endif
break;
default: /* 0 means "no symbol" */
/* debug$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) * bfd_coff_symesz (abfd);
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) / bfd_coff_symesz (abfd);
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) * bfd_coff_symesz (abfd);
}
breakloop:
return sec_flags;
}
/* The PE version; see above for the general comments.
Since to set the SEC_LINK_ONCE and associated flags, we have to
@@ -709,318 +967,116 @@ styp_to_sec_flags (abfd, hdr, name, section)
static flagword
styp_to_sec_flags (abfd, hdr, name, section)
bfd *abfd ATTRIBUTE_UNUSED;
bfd *abfd;
PTR hdr;
const char *name;
asection *section;
{
struct internal_scnhdr *internal_s = (struct internal_scnhdr *) hdr;
long styp_flags = internal_s->s_flags;
flagword sec_flags = 0;
flagword sec_flags;
if (styp_flags & STYP_DSECT)
abort (); /* Don't know what to do */
#ifdef SEC_NEVER_LOAD
if (styp_flags & STYP_NOLOAD)
sec_flags |= SEC_NEVER_LOAD;
#endif
if (styp_flags & STYP_GROUP)
abort (); /* Don't know what to do */
/* skip IMAGE_SCN_TYPE_NO_PAD */
if (styp_flags & STYP_COPY)
abort (); /* Don't know what to do */
if (styp_flags & IMAGE_SCN_CNT_CODE)
sec_flags |= SEC_CODE | SEC_ALLOC | SEC_LOAD;
if (styp_flags & IMAGE_SCN_CNT_INITIALIZED_DATA)
sec_flags |= SEC_DATA | SEC_ALLOC | SEC_LOAD;
if (styp_flags & IMAGE_SCN_CNT_UNINITIALIZED_DATA)
sec_flags |= SEC_ALLOC;
if (styp_flags & IMAGE_SCN_LNK_OTHER)
abort (); /* Don't know what to do */
if (styp_flags & IMAGE_SCN_LNK_INFO)
/* Assume read only unless IMAGE_SCN_MEM_WRITE is specified. */
sec_flags = SEC_READONLY;
/* Process each flag bit in styp_flags in turn. */
while (styp_flags)
{
/* We mark these as SEC_DEBUGGING, but only if COFF_PAGE_SIZE is
defined. coff_compute_section_file_positions uses
COFF_PAGE_SIZE to ensure that the low order bits of the
section VMA and the file offset match. If we don't know
COFF_PAGE_SIZE, we can't ensure the correct correspondence,
and demand page loading of the file will fail. */
#ifdef COFF_PAGE_SIZE
sec_flags |= SEC_DEBUGGING;
#endif
}
if (styp_flags & STYP_OVER)
abort (); /* Don't know what to do */
if (styp_flags & IMAGE_SCN_LNK_REMOVE)
sec_flags |= SEC_EXCLUDE;
long flag = styp_flags & - styp_flags;
char * unhandled = NULL;
styp_flags &= ~ flag;
if (styp_flags & IMAGE_SCN_MEM_SHARED)
sec_flags |= SEC_SHARED;
/* COMDAT: see below */
if (styp_flags & IMAGE_SCN_MEM_DISCARDABLE)
sec_flags |= SEC_DEBUGGING;
if (styp_flags & IMAGE_SCN_MEM_NOT_CACHED)
abort ();/* Don't know what to do */
if (styp_flags & IMAGE_SCN_MEM_NOT_PAGED)
abort (); /* Don't know what to do */
/* We infer from the distinct read/write/execute bits the settings
of some of the bfd flags; the actual values, should we need them,
are also in pei_section_data (abfd, section)->pe_flags. */
/* We infer from the distinct read/write/execute bits the settings
of some of the bfd flags; the actual values, should we need them,
are also in pei_section_data (abfd, section)->pe_flags. */
if (styp_flags & IMAGE_SCN_MEM_EXECUTE)
sec_flags |= SEC_CODE; /* Probably redundant */
/* IMAGE_SCN_MEM_READ is simply ignored, assuming it always to be true. */
if ((styp_flags & IMAGE_SCN_MEM_WRITE) == 0)
sec_flags |= SEC_READONLY;
/* COMDAT gets very special treatment. */
if (styp_flags & IMAGE_SCN_LNK_COMDAT)
{
sec_flags |= SEC_LINK_ONCE;
/* Unfortunately, the PE format stores essential information in
the symbol table, of all places. We need to extract that
information now, so that objdump and the linker will know how
to handle the section without worrying about the symbols. We
can't call slurp_symtab, because the linker doesn't want the
swapped symbols. */
/* COMDAT sections are special. The first symbol is the section
symbol, which tells what kind of COMDAT section it is. The
second symbol is the "comdat symbol" - the one with the
unique name. GNU uses the section symbol for the unique
name; MS uses ".text" for every comdat section. Sigh. - DJ */
/* This is not mirrored in sec_to_styp_flags(), but there
doesn't seem to be a need to, either, and it would at best be
rather messy. */
if (_bfd_coff_get_external_symbols (abfd))
switch (flag)
{
bfd_byte *esymstart, *esym, *esymend;
int seen_state = 0;
char *target_name = NULL;
esymstart = esym = (bfd_byte *) obj_coff_external_syms (abfd);
esymend = esym + obj_raw_syment_count (abfd) * bfd_coff_symesz (abfd);
while (esym < esymend)
{
struct internal_syment isym;
char buf[SYMNMLEN + 1];
const char *symname;
bfd_coff_swap_sym_in (abfd, (PTR) esym, (PTR) &isym);
if (sizeof (internal_s->s_name) > SYMNMLEN)
{
/* This case implies that the matching symbol name
will be in the string table. */
abort ();
}
if (isym.n_scnum == section->target_index)
{
/* 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. 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 $) as the comdat symbol. */
/* All 3 branches use this */
symname = _bfd_coff_internal_syment_name (abfd, &isym, buf);
if (symname == NULL)
abort ();
switch (seen_state)
{
case 0:
{
/* The first time we've seen the symbol. */
union internal_auxent aux;
seen_state = 1;
/* If it isn't the stuff we're expecting, die;
The MS documentation is vague, but it
appears that the second entry serves BOTH
as the comdat symbol and the defining
symbol record (either C_STAT or C_EXT,
possibly with an aux entry with debug
information if it's a function.) It
appears the only way to find the second one
is to count. (On Intel, they appear to be
adjacent, but on Alpha, they have been
found separated.)
Here, we think we've found the first one,
but there's some checking we can do to be
sure. */
if (! (isym.n_sclass == C_STAT
&& isym.n_type == T_NULL
&& isym.n_value == 0))
abort ();
/* FIXME LATER: MSVC generates section names
like .text for comdats. Gas generates
names like .text$foo__Fv (in the case of a
function). See comment above for more. */
if (strcmp (name, symname) != 0)
abort ();
/* This is the section symbol. */
bfd_coff_swap_aux_in (abfd, (PTR) (esym + bfd_coff_symesz (abfd)),
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;
case STYP_DSECT:
unhandled = "STYP_DSECT";
break;
case STYP_GROUP:
unhandled = "STYP_GROUP";
break;
case STYP_COPY:
unhandled = "STYP_COPY";
break;
case STYP_OVER:
unhandled = "STYP_OVER";
break;
#ifdef SEC_NEVER_LOAD
case STYP_NOLOAD:
sec_flags |= SEC_NEVER_LOAD;
break;
#endif
case IMAGE_SCN_MEM_READ:
/* Ignored, assume it always to be true. */
break;
case IMAGE_SCN_TYPE_NO_PAD:
/* Skip. */
break;
case IMAGE_SCN_LNK_OTHER:
unhandled = "IMAGE_SCN_LNK_OTHER";
break;
case IMAGE_SCN_MEM_NOT_CACHED:
unhandled = "IMAGE_SCN_MEM_NOT_CACHED";
break;
case IMAGE_SCN_MEM_NOT_PAGED:
unhandled = "IMAGE_SCN_MEM_NOT_PAGED";
break;
case IMAGE_SCN_MEM_EXECUTE:
sec_flags |= SEC_CODE;
break;
case IMAGE_SCN_MEM_WRITE:
sec_flags &= ~ SEC_READONLY;
break;
case IMAGE_SCN_MEM_DISCARDABLE:
sec_flags |= SEC_DEBUGGING;
break;
case IMAGE_SCN_MEM_SHARED:
sec_flags |= SEC_SHARED;
break;
case IMAGE_SCN_LNK_REMOVE:
sec_flags |= SEC_EXCLUDE;
break;
case IMAGE_SCN_CNT_CODE:
sec_flags |= SEC_CODE | SEC_ALLOC | SEC_LOAD;
break;
case IMAGE_SCN_CNT_INITIALIZED_DATA:
sec_flags |= SEC_DATA | SEC_ALLOC | SEC_LOAD;
break;
case IMAGE_SCN_CNT_UNINITIALIZED_DATA:
sec_flags |= SEC_ALLOC;
break;
case IMAGE_SCN_LNK_INFO:
/* We mark these as SEC_DEBUGGING, but only if COFF_PAGE_SIZE is
defined. coff_compute_section_file_positions uses
COFF_PAGE_SIZE to ensure that the low order bits of the
section VMA and the file offset match. If we don't know
COFF_PAGE_SIZE, we can't ensure the correct correspondence,
and demand page loading of the file will fail. */
#ifdef COFF_PAGE_SIZE
sec_flags |= SEC_DEBUGGING;
#endif
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_EXACT_MATCH:
/* Not yet fully implemented ??? */
sec_flags |= SEC_LINK_DUPLICATES_SAME_CONTENTS;
break;
/* debug$S gets this case; other
implications ??? */
/* There may be no symbol... we'll search
the whole table... Is this the right
place to play this game? Or should we do
it when reading it in. */
case IMAGE_COMDAT_SELECT_ASSOCIATIVE:
#ifdef STRICT_PE_FORMAT
/* FIXME: This is not currently implemented. */
sec_flags |= SEC_LINK_DUPLICATES_DISCARD;
#else
sec_flags &= ~SEC_LINK_ONCE;
#endif
break;
default: /* 0 means "no symbol" */
/* debug$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) * bfd_coff_symesz (abfd);
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) / bfd_coff_symesz (abfd);
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) * bfd_coff_symesz (abfd);
}
breakloop:
/* SunOS requires a statement after any label. */
;
break;
case IMAGE_SCN_LNK_COMDAT:
/* COMDAT gets very special treatment. */
sec_flags = handle_COMDAT (abfd, sec_flags, hdr, name, section);
break;
default:
/* Silently ignore for now. */
break;
}
/* If the section flag was not handled, report it here. This will allow
users of the BFD library to report a problem but continue executing.
Tools which need to be aware of these problems (such as the linker)
can override the default bfd_error_handler to intercept these reports. */
if (unhandled != NULL)
(*_bfd_error_handler)
(_("%s (%s): Section flag %s (0x%x) ignored"),
bfd_get_filename (abfd), name, unhandled, flag);
}
#if defined (COFF_LONG_SECTION_NAMES) && defined (COFF_SUPPORT_GNU_LINKONCE)