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/* Support for the generic parts of most COFF variants, for BFD.

   Copyright (C) 1990-2015 Free Software Foundation, Inc.

   Written by Cygnus Support.

   This file is part of BFD, the Binary File Descriptor library.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, write to the Free Software

   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,

   MA 02110-1301, USA.  */

/* Most of this hacked by  Steve Chamberlain,

			sac@cygnus.com.  */

/*

SECTION

	coff backends

	BFD supports a number of different flavours of coff format.

	The major differences between formats are the sizes and

	alignments of fields in structures on disk, and the occasional

	extra field.

	Coff in all its varieties is implemented with a few common

	files and a number of implementation specific files. For

	example, The 88k bcs coff format is implemented in the file

	@file{coff-m88k.c}. This file @code{#include}s

	@file{coff/m88k.h} which defines the external structure of the

	coff format for the 88k, and @file{coff/internal.h} which

	defines the internal structure. @file{coff-m88k.c} also

	defines the relocations used by the 88k format

	@xref{Relocations}.

	The Intel i960 processor version of coff is implemented in

	@file{coff-i960.c}. This file has the same structure as

	@file{coff-m88k.c}, except that it includes @file{coff/i960.h}

	rather than @file{coff-m88k.h}.

SUBSECTION

	Porting to a new version of coff

	The recommended method is to select from the existing

	implementations the version of coff which is most like the one

	you want to use.  For example, we'll say that i386 coff is

	the one you select, and that your coff flavour is called foo.

	Copy @file{i386coff.c} to @file{foocoff.c}, copy

	@file{../include/coff/i386.h} to @file{../include/coff/foo.h},

	and add the lines to @file{targets.c} and @file{Makefile.in}

	so that your new back end is used. Alter the shapes of the

	structures in @file{../include/coff/foo.h} so that they match

	what you need. You will probably also have to add

	@code{#ifdef}s to the code in @file{coff/internal.h} and

	@file{coffcode.h} if your version of coff is too wild.

	You can verify that your new BFD backend works quite simply by

	building @file{objdump} from the @file{binutils} directory,

	and making sure that its version of what's going on and your

	host system's idea (assuming it has the pretty standard coff

	dump utility, usually called @code{att-dump} or just

	@code{dump}) are the same.  Then clean up your code, and send

	what you've done to Cygnus. Then your stuff will be in the

	next release, and you won't have to keep integrating it.

SUBSECTION

	How the coff backend works

SUBSUBSECTION

	File layout

	The Coff backend is split into generic routines that are

	applicable to any Coff target and routines that are specific

	to a particular target.  The target-specific routines are

	further split into ones which are basically the same for all

	Coff targets except that they use the external symbol format

	or use different values for certain constants.

	The generic routines are in @file{coffgen.c}.  These routines

	work for any Coff target.  They use some hooks into the target

	specific code; the hooks are in a @code{bfd_coff_backend_data}

	structure, one of which exists for each target.

	The essentially similar target-specific routines are in

	@file{coffcode.h}.  This header file includes executable C code.

	The various Coff targets first include the appropriate Coff

	header file, make any special defines that are needed, and

	then include @file{coffcode.h}.

	Some of the Coff targets then also have additional routines in

	the target source file itself.

	For example, @file{coff-i960.c} includes

	@file{coff/internal.h} and @file{coff/i960.h}.  It then

	defines a few constants, such as @code{I960}, and includes

	@file{coffcode.h}.  Since the i960 has complex relocation

	types, @file{coff-i960.c} also includes some code to

	manipulate the i960 relocs.  This code is not in

	@file{coffcode.h} because it would not be used by any other

	target.

SUBSUBSECTION

	Coff long section names

	In the standard Coff object format, section names are limited to

	the eight bytes available in the @code{s_name} field of the

	@code{SCNHDR} section header structure.  The format requires the

	field to be NUL-padded, but not necessarily NUL-terminated, so

	the longest section names permitted are a full eight characters.

	The Microsoft PE variants of the Coff object file format add

	an extension to support the use of long section names.  This

	extension is defined in section 4 of the Microsoft PE/COFF

	specification (rev 8.1).  If a section name is too long to fit

	into the section header's @code{s_name} field, it is instead

	placed into the string table, and the @code{s_name} field is

	filled with a slash ("/") followed by the ASCII decimal

	representation of the offset of the full name relative to the

	string table base.

	Note that this implies that the extension can only be used in object

	files, as executables do not contain a string table.  The standard

	specifies that long section names from objects emitted into executable

	images are to be truncated.

	However, as a GNU extension, BFD can generate executable images

	that contain a string table and long section names.  This

	would appear to be technically valid, as the standard only says

	that Coff debugging information is deprecated, not forbidden,

	and in practice it works, although some tools that parse PE files

	expecting the MS standard format may become confused; @file{PEview} is

	one known example.

	The functionality is supported in BFD by code implemented under

	the control of the macro @code{COFF_LONG_SECTION_NAMES}.  If not

	defined, the format does not support long section names in any way.

	If defined, it is used to initialise a flag,

	@code{_bfd_coff_long_section_names}, and a hook function pointer,

	@code{_bfd_coff_set_long_section_names}, in the Coff backend data

	structure.  The flag controls the generation of long section names

	in output BFDs at runtime; if it is false, as it will be by default

	when generating an executable image, long section names are truncated;

	if true, the long section names extension is employed.  The hook

	points to a function that allows the value of the flag to be altered

	at runtime, on formats that support long section names at all; on

	other formats it points to a stub that returns an error indication.

	With input BFDs, the flag is set according to whether any long section

	names are detected while reading the section headers.  For a completely

	new BFD, the flag is set to the default for the target format.  This

	information can be used by a client of the BFD library when deciding

	what output format to generate, and means that a BFD that is opened

	for read and subsequently converted to a writeable BFD and modified

	in-place will retain whatever format it had on input.

	If @code{COFF_LONG_SECTION_NAMES} is simply defined (blank), or is

	defined to the value "1", then long section names are enabled by

	default; if it is defined to the value zero, they are disabled by

	default (but still accepted in input BFDs).  The header @file{coffcode.h}

	defines a macro, @code{COFF_DEFAULT_LONG_SECTION_NAMES}, which is

	used in the backends to initialise the backend data structure fields

	appropriately; see the comments for further detail.

SUBSUBSECTION

	Bit twiddling

	Each flavour of coff supported in BFD has its own header file

	describing the external layout of the structures. There is also

	an internal description of the coff layout, in

	@file{coff/internal.h}. A major function of the

	coff backend is swapping the bytes and twiddling the bits to

	translate the external form of the structures into the normal

	internal form. This is all performed in the

	@code{bfd_swap}_@i{thing}_@i{direction} routines. Some

	elements are different sizes between different versions of

	coff; it is the duty of the coff version specific include file

	to override the definitions of various packing routines in

	@file{coffcode.h}. E.g., the size of line number entry in coff is

	sometimes 16 bits, and sometimes 32 bits. @code{#define}ing

	@code{PUT_LNSZ_LNNO} and @code{GET_LNSZ_LNNO} will select the

	correct one. No doubt, some day someone will find a version of

	coff which has a varying field size not catered to at the

	moment. To port BFD, that person will have to add more @code{#defines}.

	Three of the bit twiddling routines are exported to

	@code{gdb}; @code{coff_swap_aux_in}, @code{coff_swap_sym_in}

	and @code{coff_swap_lineno_in}. @code{GDB} reads the symbol

	table on its own, but uses BFD to fix things up.  More of the

	bit twiddlers are exported for @code{gas};

	@code{coff_swap_aux_out}, @code{coff_swap_sym_out},

	@code{coff_swap_lineno_out}, @code{coff_swap_reloc_out},

	@code{coff_swap_filehdr_out}, @code{coff_swap_aouthdr_out},

	@code{coff_swap_scnhdr_out}. @code{Gas} currently keeps track

	of all the symbol table and reloc drudgery itself, thereby

	saving the internal BFD overhead, but uses BFD to swap things

	on the way out, making cross ports much safer.  Doing so also

	allows BFD (and thus the linker) to use the same header files

	as @code{gas}, which makes one avenue to disaster disappear.

SUBSUBSECTION

	Symbol reading

	The simple canonical form for symbols used by BFD is not rich

	enough to keep all the information available in a coff symbol

	table. The back end gets around this problem by keeping the original

	symbol table around, "behind the scenes".

	When a symbol table is requested (through a call to

	@code{bfd_canonicalize_symtab}), a request gets through to

	@code{coff_get_normalized_symtab}. This reads the symbol table from

	the coff file and swaps all the structures inside into the

	internal form. It also fixes up all the pointers in the table

	(represented in the file by offsets from the first symbol in

	the table) into physical pointers to elements in the new

	internal table. This involves some work since the meanings of

	fields change depending upon context: a field that is a

	pointer to another structure in the symbol table at one moment

	may be the size in bytes of a structure at the next.  Another

	pass is made over the table. All symbols which mark file names

	(<> symbols) are modified so that the internal

	string points to the value in the auxent (the real filename)

	rather than the normal text associated with the symbol

	(@code{".file"}).

	At this time the symbol names are moved around. Coff stores

	all symbols less than nine characters long physically

	within the symbol table; longer strings are kept at the end of

	the file in the string table. This pass moves all strings

	into memory and replaces them with pointers to the strings.

	The symbol table is massaged once again, this time to create

	the canonical table used by the BFD application. Each symbol

	is inspected in turn, and a decision made (using the

	@code{sclass} field) about the various flags to set in the

	@code{asymbol}.  @xref{Symbols}. The generated canonical table

	shares strings with the hidden internal symbol table.

	Any linenumbers are read from the coff file too, and attached

	to the symbols which own the functions the linenumbers belong to.

SUBSUBSECTION

	Symbol writing

	Writing a symbol to a coff file which didn't come from a coff

	file will lose any debugging information. The @code{asymbol}

	structure remembers the BFD from which the symbol was taken, and on

	output the back end makes sure that the same destination target as

	source target is present.

	When the symbols have come from a coff file then all the

	debugging information is preserved.

	Symbol tables are provided for writing to the back end in a

	vector of pointers to pointers. This allows applications like

	the linker to accumulate and output large symbol tables

	without having to do too much byte copying.

	This function runs through the provided symbol table and

	patches each symbol marked as a file place holder

	(@code{C_FILE}) to point to the next file place holder in the

	list. It also marks each @code{offset} field in the list with

	the offset from the first symbol of the current symbol.

	Another function of this procedure is to turn the canonical

	value form of BFD into the form used by coff. Internally, BFD

	expects symbol values to be offsets from a section base; so a

	symbol physically at 0x120, but in a section starting at

	0x100, would have the value 0x20. Coff expects symbols to

	contain their final value, so symbols have their values

	changed at this point to reflect their sum with their owning

	section.  This transformation uses the

	<> field of the @code{asymbol}'s

	@code{asection} @xref{Sections}.

	o <>

	This routine runs though the provided symbol table and uses

	the offsets generated by the previous pass and the pointers

	generated when the symbol table was read in to create the

	structured hierarchy required by coff. It changes each pointer

	to a symbol into the index into the symbol table of the asymbol.

	o <>

	This routine runs through the symbol table and patches up the

	symbols from their internal form into the coff way, calls the

	bit twiddlers, and writes out the table to the file.

*/

/*

INTERNAL_DEFINITION

	coff_symbol_type

DESCRIPTION

	The hidden information for an <> is described in a

	<>:

CODE_FRAGMENT

.

.typedef struct coff_ptr_struct

.{

.  {* Remembers the offset from the first symbol in the file for

.     this symbol. Generated by coff_renumber_symbols. *}

.  unsigned int offset;

.

.  {* Should the value of this symbol be renumbered.  Used for

.     XCOFF C_BSTAT symbols.  Set by coff_slurp_symbol_table.  *}

.  unsigned int fix_value : 1;

.

.  {* Should the tag field of this symbol be renumbered.

.     Created by coff_pointerize_aux. *}

.  unsigned int fix_tag : 1;

.

.  {* Should the endidx field of this symbol be renumbered.

.     Created by coff_pointerize_aux. *}

.  unsigned int fix_end : 1;

.

.  {* Should the x_csect.x_scnlen field be renumbered.

.     Created by coff_pointerize_aux. *}

.  unsigned int fix_scnlen : 1;

.

.  {* Fix up an XCOFF C_BINCL/C_EINCL symbol.  The value is the

.     index into the line number entries.  Set by coff_slurp_symbol_table.  *}

.  unsigned int fix_line : 1;

.

.  {* The container for the symbol structure as read and translated

.     from the file. *}

.  union

.  {

.    union internal_auxent auxent;

.    struct internal_syment syment;

.  } u;

.

. {* Selector for the union above.  *}

. bfd_boolean is_sym;

.} combined_entry_type;

.

.

.{* Each canonical asymbol really looks like this: *}

.

.typedef struct coff_symbol_struct

.{

.  {* The actual symbol which the rest of BFD works with *}

.  asymbol symbol;

.

.  {* A pointer to the hidden information for this symbol *}

.  combined_entry_type *native;

.

.  {* A pointer to the linenumber information for this symbol *}

.  struct lineno_cache_entry *lineno;

.

.  {* Have the line numbers been relocated yet ? *}

.  bfd_boolean done_lineno;

.} coff_symbol_type;

*/

#include "libiberty.h"

#ifdef COFF_WITH_PE

#include "peicode.h"

#else

#include "coffswap.h"

#endif

#define STRING_SIZE_SIZE 4

#define DOT_DEBUG	".debug"

#define DOT_ZDEBUG	".zdebug"

#define GNU_LINKONCE_WI ".gnu.linkonce.wi."

#define GNU_LINKONCE_WT ".gnu.linkonce.wt."

#define DOT_RELOC	".reloc"

#if defined (COFF_LONG_SECTION_NAMES)

/* Needed to expand the inputs to BLANKOR1TOODD.  */

#define COFFLONGSECTIONCATHELPER(x,y)    x ## y

/* If the input macro Y is blank or '1', return an odd number; if it is

   '0', return an even number.  Result undefined in all other cases.  */

#define BLANKOR1TOODD(y)                 COFFLONGSECTIONCATHELPER(1,y)

/* Defined to numerical 0 or 1 according to whether generation of long

   section names is disabled or enabled by default.  */

#define COFF_ENABLE_LONG_SECTION_NAMES   (BLANKOR1TOODD(COFF_LONG_SECTION_NAMES) & 1)

/* Where long section names are supported, we allow them to be enabled

   and disabled at runtime, so select an appropriate hook function for

   _bfd_coff_set_long_section_names.  */

#define COFF_LONG_SECTION_NAMES_SETTER   bfd_coff_set_long_section_names_allowed

#else /* !defined (COFF_LONG_SECTION_NAMES) */

/* If long section names are not supported, this stub disallows any

   attempt to enable them at run-time.  */

#define COFF_LONG_SECTION_NAMES_SETTER   bfd_coff_set_long_section_names_disallowed

#endif /* defined (COFF_LONG_SECTION_NAMES) */

/* Define a macro that can be used to initialise both the fields relating

   to long section names in the backend data struct simultaneously.  */

#if COFF_ENABLE_LONG_SECTION_NAMES

#define COFF_DEFAULT_LONG_SECTION_NAMES  (TRUE), COFF_LONG_SECTION_NAMES_SETTER

#else /* !COFF_ENABLE_LONG_SECTION_NAMES */

#define COFF_DEFAULT_LONG_SECTION_NAMES  (FALSE), COFF_LONG_SECTION_NAMES_SETTER

#endif /* COFF_ENABLE_LONG_SECTION_NAMES */

#if defined (COFF_LONG_SECTION_NAMES)

static bfd_boolean bfd_coff_set_long_section_names_allowed

  (bfd *, int);

#else /* !defined (COFF_LONG_SECTION_NAMES) */

static bfd_boolean bfd_coff_set_long_section_names_disallowed

  (bfd *, int);

#endif /* defined (COFF_LONG_SECTION_NAMES) */

static long sec_to_styp_flags

  (const char *, flagword);

static bfd_boolean styp_to_sec_flags

  (bfd *, void *, const char *, asection *, flagword *);

static bfd_boolean coff_bad_format_hook

  (bfd *, void *);

static void coff_set_custom_section_alignment

  (bfd *, asection *, const struct coff_section_alignment_entry *,

   const unsigned int);

static bfd_boolean coff_new_section_hook

  (bfd *, asection *);

static bfd_boolean coff_set_arch_mach_hook

  (bfd *, void *);

static bfd_boolean coff_write_relocs

  (bfd *, int);

static bfd_boolean coff_set_flags

  (bfd *, unsigned int *, unsigned short *);

static bfd_boolean coff_set_arch_mach

  (bfd *, enum bfd_architecture, unsigned long) ATTRIBUTE_UNUSED;

static bfd_boolean coff_compute_section_file_positions

  (bfd *);

static bfd_boolean coff_write_object_contents

  (bfd *) ATTRIBUTE_UNUSED;

static bfd_boolean coff_set_section_contents

  (bfd *, asection *, const void *, file_ptr, bfd_size_type);

static void * buy_and_read

  (bfd *, file_ptr, bfd_size_type);

static bfd_boolean coff_slurp_line_table

  (bfd *, asection *);

static bfd_boolean coff_slurp_symbol_table

  (bfd *);

static enum coff_symbol_classification coff_classify_symbol

  (bfd *, struct internal_syment *);

static bfd_boolean coff_slurp_reloc_table

  (bfd *, asection *, asymbol **);

static long coff_canonicalize_reloc

  (bfd *, asection *, arelent **, asymbol **);

#ifndef coff_mkobject_hook

static void * coff_mkobject_hook

  (bfd *, void *,  void *);

#endif

#ifdef COFF_WITH_PE

static flagword handle_COMDAT

  (bfd *, flagword, void *, const char *, asection *);

#endif

#ifdef COFF_IMAGE_WITH_PE

static bfd_boolean coff_read_word

  (bfd *, unsigned int *);

static unsigned int coff_compute_checksum

  (bfd *);

static bfd_boolean coff_apply_checksum

  (bfd *);

#endif

#ifdef TICOFF

static bfd_boolean ticoff0_bad_format_hook

  (bfd *, void * );

static bfd_boolean ticoff1_bad_format_hook

  (bfd *, void * );

#endif

/* void warning(); */

#if defined (COFF_LONG_SECTION_NAMES)

static bfd_boolean

bfd_coff_set_long_section_names_allowed (bfd *abfd, int enable)

{

  coff_backend_info (abfd)->_bfd_coff_long_section_names = enable;

  return TRUE;

}

#else /* !defined (COFF_LONG_SECTION_NAMES) */

static bfd_boolean

bfd_coff_set_long_section_names_disallowed (bfd *abfd, int enable)

{

  (void) abfd;

  (void) enable;

  return FALSE;

}

#endif /* defined (COFF_LONG_SECTION_NAMES) */

/* Return a word with STYP_* (scnhdr.s_flags) flags set to represent

   the incoming SEC_* flags.  The inverse of this function is

   styp_to_sec_flags().  NOTE: If you add to/change this routine, you

   should probably mirror the changes in styp_to_sec_flags().  */

#ifndef COFF_WITH_PE

/* Macros for setting debugging flags.  */

#ifdef STYP_DEBUG

#define STYP_XCOFF_DEBUG STYP_DEBUG

#else

#define STYP_XCOFF_DEBUG STYP_INFO

#endif

#ifdef COFF_ALIGN_IN_S_FLAGS

#define STYP_DEBUG_INFO STYP_DSECT

#else

#define STYP_DEBUG_INFO STYP_INFO

#endif

static long

sec_to_styp_flags (const char *sec_name, flagword sec_flags)

{

  long styp_flags = 0;

  if (!strcmp (sec_name, _TEXT))

    {

      styp_flags = STYP_TEXT;

    }

  else if (!strcmp (sec_name, _DATA))

    {

      styp_flags = STYP_DATA;

    }

  else if (!strcmp (sec_name, _BSS))

    {

      styp_flags = STYP_BSS;

#ifdef _COMMENT

    }

  else if (!strcmp (sec_name, _COMMENT))

    {

      styp_flags = STYP_INFO;

#endif /* _COMMENT */

#ifdef _LIB

    }

  else if (!strcmp (sec_name, _LIB))

    {

      styp_flags = STYP_LIB;

#endif /* _LIB */

#ifdef _LIT

    }

  else if (!strcmp (sec_name, _LIT))

    {

      styp_flags = STYP_LIT;

#endif /* _LIT */

    }

  else if (CONST_STRNEQ (sec_name, DOT_DEBUG)

           || CONST_STRNEQ (sec_name, DOT_ZDEBUG))

    {

      /* Handle the XCOFF debug section and DWARF2 debug sections.  */

      if (!sec_name[6])

	styp_flags = STYP_XCOFF_DEBUG;

      else

	styp_flags = STYP_DEBUG_INFO;

    }

  else if (CONST_STRNEQ (sec_name, ".stab"))

    {

      styp_flags = STYP_DEBUG_INFO;

    }

#ifdef COFF_LONG_SECTION_NAMES

  else if (CONST_STRNEQ (sec_name, GNU_LINKONCE_WI)

  	   || CONST_STRNEQ (sec_name, GNU_LINKONCE_WT))

    {

      styp_flags = STYP_DEBUG_INFO;

    }

#endif

#ifdef RS6000COFF_C

  else if (!strcmp (sec_name, _PAD))

    {

      styp_flags = STYP_PAD;

    }

  else if (!strcmp (sec_name, _LOADER))

    {

      styp_flags = STYP_LOADER;

    }

  else if (!strcmp (sec_name, _EXCEPT))

    {

      styp_flags = STYP_EXCEPT;

    }

  else if (!strcmp (sec_name, _TYPCHK))

    {

      styp_flags = STYP_TYPCHK;

    }

  else if (sec_flags & SEC_DEBUGGING)

    {

      int i;

      for (i = 0; i < XCOFF_DWSECT_NBR_NAMES; i++)

        if (!strcmp (sec_name, xcoff_dwsect_names[i].name))

          {

            styp_flags = STYP_DWARF | xcoff_dwsect_names[i].flag;

            break;

          }

    }

#endif

  /* Try and figure out what it should be */

  else if (sec_flags & SEC_CODE)

    {

      styp_flags = STYP_TEXT;

    }

  else if (sec_flags & SEC_DATA)

    {

      styp_flags = STYP_DATA;

    }

  else if (sec_flags & SEC_READONLY)

    {

#ifdef STYP_LIT			/* 29k readonly text/data section */

      styp_flags = STYP_LIT;

#else

      styp_flags = STYP_TEXT;

#endif /* STYP_LIT */

    }

  else if (sec_flags & SEC_LOAD)

    {

      styp_flags = STYP_TEXT;

    }

  else if (sec_flags & SEC_ALLOC)

    {

      styp_flags = STYP_BSS;

    }

#ifdef STYP_CLINK

  if (sec_flags & SEC_TIC54X_CLINK)

    styp_flags |= STYP_CLINK;

#endif

#ifdef STYP_BLOCK

  if (sec_flags & SEC_TIC54X_BLOCK)

    styp_flags |= STYP_BLOCK;

#endif

#ifdef STYP_NOLOAD

  if ((sec_flags & (SEC_NEVER_LOAD | SEC_COFF_SHARED_LIBRARY)) != 0)

    styp_flags |= STYP_NOLOAD;

#endif

  return styp_flags;

}

#else /* COFF_WITH_PE */

/* The PE version; see above for the general comments.  The non-PE

   case seems to be more guessing, and breaks PE format; specifically,

   .rdata is readonly, but it sure ain't text.  Really, all this

   should be set up properly in gas (or whatever assembler is in use),

   and honor whatever objcopy/strip, etc. sent us as input.  */

static long

sec_to_styp_flags (const char *sec_name, flagword sec_flags)

{

  long styp_flags = 0;

  bfd_boolean is_dbg = FALSE;

  if (CONST_STRNEQ (sec_name, DOT_DEBUG)

      || CONST_STRNEQ (sec_name, DOT_ZDEBUG)

#ifdef COFF_LONG_SECTION_NAMES

      || CONST_STRNEQ (sec_name, GNU_LINKONCE_WI)

      || CONST_STRNEQ (sec_name, GNU_LINKONCE_WT)

#endif

      || CONST_STRNEQ (sec_name, ".stab"))

    is_dbg = TRUE;

  /* caution: there are at least three groups of symbols that have

     very similar bits and meanings: IMAGE_SCN*, SEC_*, and STYP_*.

     SEC_* are the BFD internal flags, used for generic BFD

     information.  STYP_* are the COFF section flags which appear in

     COFF files.  IMAGE_SCN_* are the PE section flags which appear in

     PE files.  The STYP_* flags and the IMAGE_SCN_* flags overlap,

     but there are more IMAGE_SCN_* flags.  */

  /* FIXME: There is no gas syntax to specify the debug section flag.  */

  if (is_dbg)

    {

      sec_flags &= (SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD

      		    | SEC_LINK_DUPLICATES_SAME_CONTENTS

      		    | SEC_LINK_DUPLICATES_SAME_SIZE);

      sec_flags |= SEC_DEBUGGING | SEC_READONLY;

    }

  /* skip LOAD */

  /* READONLY later */

  /* skip RELOC */

  if ((sec_flags & SEC_CODE) != 0)

    styp_flags |= IMAGE_SCN_CNT_CODE;

  if ((sec_flags & (SEC_DATA | SEC_DEBUGGING)) != 0)

    styp_flags |= IMAGE_SCN_CNT_INITIALIZED_DATA;

  if ((sec_flags & SEC_ALLOC) != 0 && (sec_flags & SEC_LOAD) == 0)

    styp_flags |= IMAGE_SCN_CNT_UNINITIALIZED_DATA;  /* ==STYP_BSS */

  /* skip ROM */

  /* skip constRUCTOR */

  /* skip CONTENTS */

  if ((sec_flags & SEC_IS_COMMON) != 0)

    styp_flags |= IMAGE_SCN_LNK_COMDAT;

  if ((sec_flags & SEC_DEBUGGING) != 0)

    styp_flags |= IMAGE_SCN_MEM_DISCARDABLE;

  if ((sec_flags & SEC_EXCLUDE) != 0 && !is_dbg)

    styp_flags |= IMAGE_SCN_LNK_REMOVE;

  if ((sec_flags & SEC_NEVER_LOAD) != 0 && !is_dbg)

    styp_flags |= IMAGE_SCN_LNK_REMOVE;

  /* skip IN_MEMORY */

  /* skip SORT */

  if (sec_flags & SEC_LINK_ONCE)

    styp_flags |= IMAGE_SCN_LNK_COMDAT;

  if ((sec_flags

       & (SEC_LINK_DUPLICATES_DISCARD | SEC_LINK_DUPLICATES_SAME_CONTENTS

          | SEC_LINK_DUPLICATES_SAME_SIZE)) != 0)

    styp_flags |= IMAGE_SCN_LNK_COMDAT;

  /* skip LINKER_CREATED */

  if ((sec_flags & SEC_COFF_NOREAD) == 0)

    styp_flags |= IMAGE_SCN_MEM_READ;     /* Invert NOREAD for read.  */

  if ((sec_flags & SEC_READONLY) == 0)

    styp_flags |= IMAGE_SCN_MEM_WRITE;    /* Invert READONLY for write.  */

  if (sec_flags & SEC_CODE)

    styp_flags |= IMAGE_SCN_MEM_EXECUTE;  /* CODE->EXECUTE.  */

  if (sec_flags & SEC_COFF_SHARED)

    styp_flags |= IMAGE_SCN_MEM_SHARED;   /* Shared remains meaningful.  */

  return styp_flags;

}

#endif /* COFF_WITH_PE */

/* Return a word with SEC_* flags set to represent the incoming STYP_*

   flags (from scnhdr.s_flags).  The inverse of this function is

   sec_to_styp_flags().  NOTE: If you add to/change this routine, you

   should probably mirror the changes in sec_to_styp_flags().  */

#ifndef COFF_WITH_PE

static bfd_boolean

styp_to_sec_flags (bfd *abfd ATTRIBUTE_UNUSED,

		   void * hdr,

		   const char *name,

		   asection *section ATTRIBUTE_UNUSED,

		   flagword *flags_ptr)

{

  struct internal_scnhdr *internal_s = (struct internal_scnhdr *) hdr;

  long styp_flags = internal_s->s_flags;

  flagword sec_flags = 0;

#ifdef STYP_BLOCK

  if (styp_flags & STYP_BLOCK)

    sec_flags |= SEC_TIC54X_BLOCK;

#endif

#ifdef STYP_CLINK

  if (styp_flags & STYP_CLINK)

    sec_flags |= SEC_TIC54X_CLINK;

#endif

#ifdef STYP_NOLOAD

  if (styp_flags & STYP_NOLOAD)

    sec_flags |= SEC_NEVER_LOAD;

#endif /* STYP_NOLOAD */

  /* For 386 COFF, at least, an unloadable text or data section is

     actually a shared library section.  */

  if (styp_flags & STYP_TEXT)

    {

      if (sec_flags & SEC_NEVER_LOAD)

	sec_flags |= SEC_CODE | SEC_COFF_SHARED_LIBRARY;

      else

	sec_flags |= SEC_CODE | SEC_LOAD | SEC_ALLOC;

    }

  else if (styp_flags & STYP_DATA)

    {

      if (sec_flags & SEC_NEVER_LOAD)

	sec_flags |= SEC_DATA | SEC_COFF_SHARED_LIBRARY;

      else

	sec_flags |= SEC_DATA | SEC_LOAD | SEC_ALLOC;

    }

  else if (styp_flags & STYP_BSS)

    {

#ifdef BSS_NOLOAD_IS_SHARED_LIBRARY

      if (sec_flags & SEC_NEVER_LOAD)

	sec_flags |= SEC_ALLOC | SEC_COFF_SHARED_LIBRARY;

      else

#endif

	sec_flags |= SEC_ALLOC;

    }

  else if (styp_flags & STYP_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.  */

#if defined (COFF_PAGE_SIZE) && !defined (COFF_ALIGN_IN_S_FLAGS)

      sec_flags |= SEC_DEBUGGING;

#endif

    }

  else if (styp_flags & STYP_PAD)

    sec_flags = 0;

#ifdef RS6000COFF_C

  else if (styp_flags & STYP_EXCEPT)

    sec_flags |= SEC_LOAD;

  else if (styp_flags & STYP_LOADER)

    sec_flags |= SEC_LOAD;

  else if (styp_flags & STYP_TYPCHK)

    sec_flags |= SEC_LOAD;

  else if (styp_flags & STYP_DWARF)

    sec_flags |= SEC_DEBUGGING;

#endif

  else if (strcmp (name, _TEXT) == 0)

    {

      if (sec_flags & SEC_NEVER_LOAD)

	sec_flags |= SEC_CODE | SEC_COFF_SHARED_LIBRARY;

      else

	sec_flags |= SEC_CODE | SEC_LOAD | SEC_ALLOC;

    }

  else if (strcmp (name, _DATA) == 0)

    {

      if (sec_flags & SEC_NEVER_LOAD)

	sec_flags |= SEC_DATA | SEC_COFF_SHARED_LIBRARY;

      else

	sec_flags |= SEC_DATA | SEC_LOAD | SEC_ALLOC;

    }

  else if (strcmp (name, _BSS) == 0)

    {

#ifdef BSS_NOLOAD_IS_SHARED_LIBRARY

      if (sec_flags & SEC_NEVER_LOAD)

	sec_flags |= SEC_ALLOC | SEC_COFF_SHARED_LIBRARY;

      else

#endif

	sec_flags |= SEC_ALLOC;

    }

  else if (CONST_STRNEQ (name, DOT_DEBUG)

	   || CONST_STRNEQ (name, DOT_ZDEBUG)

#ifdef _COMMENT

	   || strcmp (name, _COMMENT) == 0

#endif

#ifdef COFF_LONG_SECTION_NAMES

	   || CONST_STRNEQ (name, GNU_LINKONCE_WI)

	   || CONST_STRNEQ (name, GNU_LINKONCE_WT)

#endif

	   || CONST_STRNEQ (name, ".stab"))

    {

#ifdef COFF_PAGE_SIZE

      sec_flags |= SEC_DEBUGGING;

#endif

    }

#ifdef _LIB

  else if (strcmp (name, _LIB) == 0)

    ;

#endif

#ifdef _LIT

  else if (strcmp (name, _LIT) == 0)

    sec_flags = SEC_LOAD | SEC_ALLOC | SEC_READONLY;

#endif

  else

    sec_flags |= SEC_ALLOC | SEC_LOAD;

#ifdef STYP_LIT			/* A29k readonly text/data section type.  */

  if ((styp_flags & STYP_LIT) == STYP_LIT)

    sec_flags = (SEC_LOAD | SEC_ALLOC | SEC_READONLY);

#endif /* STYP_LIT */

#ifdef STYP_OTHER_LOAD		/* Other loaded sections.  */

  if (styp_flags & STYP_OTHER_LOAD)

    sec_flags = (SEC_LOAD | SEC_ALLOC);

#endif /* STYP_SDATA */

#if defined (COFF_LONG_SECTION_NAMES) && defined (COFF_SUPPORT_GNU_LINKONCE)

  /* As a GNU extension, if the name begins with .gnu.linkonce, we

     only link a single copy of the section.  This is used to support

     g++.  g++ will emit each template expansion in its own section.

     The symbols will be defined as weak, so that multiple definitions

     are permitted.  The GNU linker extension is to actually discard

     all but one of the sections.  */

  if (CONST_STRNEQ (name, ".gnu.linkonce"))

    sec_flags |= SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD;

#endif

  if (flags_ptr == NULL)

    return FALSE;

  * flags_ptr = sec_flags;

  return TRUE;

}

#else /* COFF_WITH_PE */

static flagword

handle_COMDAT (bfd * abfd,

	       flagword sec_flags,

	       void * 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, esym, & isym);

      BFD_ASSERT (sizeof (internal_s->s_name) <= SYMNMLEN);

      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$, where

	      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  (whatever

	     follows the $) as the comdat symbol.  */

	  /* All 3 branches use this.  */

	  symname = _bfd_coff_internal_syment_name (abfd, &isym, buf);

	  /* PR 17512 file: 078-11867-0.004  */

	  if (symname == NULL)

	    {

	      _bfd_error_handler (_("%B: unable to load COMDAT section name"), abfd);

	      break;

	    }

	  switch (seen_state)

	    {

	    case 0:

	      {

		/* The first time we've seen the symbol.  */

		union internal_auxent aux;

		/* 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_sclass == C_EXT)

		       && BTYPE (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 (isym.n_sclass == C_STAT && strcmp (name, symname) != 0)

		  _bfd_error_handler (_("%B: warning: COMDAT symbol '%s' does not match section name '%s'"),

				      abfd, symname, name);

		seen_state = 1;

		/* PR 17512: file: e2cfe54f.  */

		if (esym + bfd_coff_symesz (abfd) >= esymend)

		  {

		    _bfd_error_handler (_("%B: warning: No symbol for section '%s' found"),

					abfd, symname);

		    break;

		  }

		/* This is the section symbol.  */

		bfd_coff_swap_aux_in (abfd, (esym + bfd_coff_symesz (abfd)),

				      isym.n_type, isym.n_sclass,

				      0, isym.n_numaux, & 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;

		bfd_size_type amt;

		/* This must the second symbol with the

		   section #.  It is the actual symbol name.

		   Intel puts the two adjacent, but Alpha (at

		   least) spreads them out.  */

		amt = sizeof (struct coff_comdat_info);

		coff_section_data (abfd, section)->comdat

		  = (struct coff_comdat_info *) bfd_alloc (abfd, amt);