GDB 7.6.50

libiberty/simple-object-xcoff.c

Index: libiberty/simple-object-xcoff.c
diff --git a/libiberty/simple-object-xcoff.c b/libiberty/simple-object-xcoff.c
new file mode 100644
index 0000000000000000000000000000000000000000..ff1dc18079eb3a510362d494cf590a55d9262997
--- /dev/null
+++ b/libiberty/simple-object-xcoff.c
@@ -0,0 +1,898 @@
+/* simple-object-coff.c -- routines to manipulate XCOFF object files.
+   Copyright 2013 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor, Google and David Edelsohn, IBM.
+
+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 2, 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, 51 Franklin Street - Fifth Floor,
+Boston, MA 02110-1301, USA.  */
+
+#include "config.h"
+#include "libiberty.h"
+#include "simple-object.h"
+
+#include <errno.h>
+#include <stddef.h>
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
+
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+
+#ifdef HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+
+#include "simple-object-common.h"
+
+/* XCOFF structures and constants.  */
+
+/* XCOFF file header.  */
+
+struct external_filehdr
+{
+  unsigned char f_magic[2];	/* magic number			*/
+  unsigned char f_nscns[2];	/* number of sections		*/
+  unsigned char f_timdat[4];	/* time & date stamp		*/
+  union
+  {
+    struct
+    {
+      unsigned char f_symptr[4];	/* file pointer to symtab	*/
+      unsigned char f_nsyms[4];	/* number of symtab entries	*/
+      unsigned char f_opthdr[2];	/* sizeof(optional hdr)		*/
+      unsigned char f_flags[2];	/* flags			*/
+    } xcoff32;
+    struct
+    {
+      unsigned char f_symptr[8];	/* file pointer to symtab	*/
+      unsigned char f_opthdr[2];	/* sizeof(optional hdr)		*/
+      unsigned char f_flags[2];	/* flags			*/
+      unsigned char f_nsyms[4];	/* number of symtab entries	*/
+    } xcoff64;
+  } u;
+};
+
+/* Bits for filehdr f_flags field.  */
+
+#define F_EXEC			(0x0002)
+
+/* The known values of f_magic in an XCOFF file header.  */
+
+#define U802WRMAGIC 0730        /* Writeable text segments.  */
+#define U802ROMAGIC 0735        /* Readonly sharable text segments.  */
+#define U802TOCMAGIC 0737       /* Readonly text segments and TOC.  */
+#define U803XTOCMAGIC 0757      /* Aix 4.3 64-bit XCOFF.  */
+#define U64_TOCMAGIC 0767       /* AIX 5+ 64-bit XCOFF.  */
+
+/* XCOFF section header.  */
+
+struct external_scnhdr
+{
+  unsigned char s_name[8];	/* section name				*/
+  union
+  {
+    struct
+    {
+      unsigned char s_paddr[4];	/* physical address, aliased s_nlib 	*/
+      unsigned char s_vaddr[4];	/* virtual address			*/
+      unsigned char s_size[4];	/* section size				*/
+      unsigned char s_scnptr[4];	/* file ptr to raw data for section */
+      unsigned char s_relptr[4];	/* file ptr to relocation	*/
+      unsigned char s_lnnoptr[4];	/* file ptr to line numbers	*/
+      unsigned char s_nreloc[2];	/* number of relocation entries	*/
+      unsigned char s_nlnno[2];	/* number of line number entries	*/
+      unsigned char s_flags[4];	/* flags				*/
+    } xcoff32;
+    struct
+    {
+      unsigned char s_paddr[8];	/* physical address, aliased s_nlib 	*/
+      unsigned char s_vaddr[8];	/* virtual address			*/
+      unsigned char s_size[8];	/* section size				*/
+      unsigned char s_scnptr[8];	/* file ptr to raw data for section */
+      unsigned char s_relptr[8];	/* file ptr to relocation	*/
+      unsigned char s_lnnoptr[8];	/* file ptr to line numbers	*/
+      unsigned char s_nreloc[4];	/* number of relocation entries	*/
+      unsigned char s_nlnno[4];	/* number of line number entries	*/
+      unsigned char s_flags[4];	/* flags				*/
+    } xcoff64;
+  } u;
+};
+
+#define SCNHSZ32	(40)
+#define SCNHSZ64	(68)
+
+/* The length of the s_name field in struct external_scnhdr.  */
+
+#define SCNNMLEN	(8)
+
+/* Bits for scnhdr s_flags field.  */
+
+#define STYP_DATA			0x40
+
+/* XCOFF symbol table entry.  */
+
+
+#define N_SYMNMLEN	(8)	/* # characters in a symbol name	*/
+
+/* The format of an XCOFF symbol-table entry.  */
+struct external_syment
+{
+  union {
+    struct {
+      union {
+        /* The name of the symbol.  There is an implicit null character
+           after the end of the array.  */
+        char n_name[N_SYMNMLEN];
+        struct {
+          /* If n_zeroes is zero, n_offset is the offset the name from
+             the start of the string table.  */
+          unsigned char n_zeroes[4];
+          unsigned char n_offset[4];
+        } n;
+      } n;
+
+      /* The symbol's value.  */
+      unsigned char n_value[4];
+    } xcoff32;
+    struct {
+      /* The symbol's value.  */
+      unsigned char n_value[8];
+
+      /* The offset of the symbol from the start of the string table.  */
+      unsigned char n_offset[4];
+    } xcoff64;
+  } u;
+
+  /* The number of the section to which this symbol belongs.  */
+  unsigned char n_scnum[2];
+
+  /* The type of symbol.  (It can be interpreted as an n_lang
+     and an n_cpu byte, but we don't care about that here.)  */
+  unsigned char n_type[2];
+
+  /* The class of symbol (a C_* value).  */
+  unsigned char n_sclass[1];
+
+  /* The number of auxiliary symbols attached to this entry.  */
+  unsigned char n_numaux[1];
+};
+
+#define SYMESZ		(18)
+
+/* Length allowed for filename in aux sym format 4.  */
+
+#define FILNMLEN	(14)
+
+/* Omits x_sym and other unused variants.  */
+
+union external_auxent
+{
+  /* Aux sym format 4: file.  */
+  union
+  {
+    char x_fname[FILNMLEN];
+    struct
+    {
+      unsigned char x_zeroes[4];
+      unsigned char x_offset[4];
+      unsigned char x_pad[FILNMLEN-8];
+      unsigned char x_ftype;
+    } _x;
+  } x_file;
+  /* Aux sym format 5: section.  */
+  struct
+  {
+    unsigned char x_scnlen[4];		/* section length		*/
+    unsigned char x_nreloc[2];		/* # relocation entries		*/
+    unsigned char x_nlinno[2];		/* # line numbers		*/
+  } x_scn;
+  /* CSECT auxiliary entry.  */
+  union
+  {
+    struct
+    {
+      struct
+      {
+	unsigned char x_scnlen[4];	/* csect length */
+	unsigned char x_parmhash[4];	/* parm type hash index */
+	unsigned char x_snhash[2];	/* sect num with parm hash */
+	unsigned char x_smtyp;		/* symbol align and type */
+	unsigned char x_smclas;		/* storage mapping class */
+	unsigned char x_stab;		/* dbx stab info index */
+	unsigned char x_snstab[2];	/* sect num with dbx stab */
+      } x_csect;
+    } xcoff32;
+    struct
+    {
+      struct
+      {
+	unsigned char x_scnlen_lo[4];	/* csect length */
+	unsigned char x_parmhash[4];	/* parm type hash index */
+	unsigned char x_snhash[2];	/* sect num with parm hash */
+	unsigned char x_smtyp;		/* symbol align and type */
+	unsigned char x_smclas;		/* storage mapping class */
+	unsigned char x_scnlen_hi[4];
+	unsigned char pad;
+	unsigned char x_auxtype;
+      } x_csect;
+    } xcoff64;
+  } u;
+  /* SECTION/DWARF auxiliary entry.  */
+  struct
+  {
+    unsigned char x_scnlen[4];		/* section length */
+    unsigned char pad1[4];
+    unsigned char x_nreloc[4];		/* number RLDs */
+  } x_sect;
+};
+
+/* Symbol-related constants.  */
+
+#define N_DEBUG		(-2)
+#define IMAGE_SYM_TYPE_NULL	(0)
+#define IMAGE_SYM_DTYPE_NULL	(0)
+#define IMAGE_SYM_CLASS_STATIC	(3)
+#define IMAGE_SYM_CLASS_FILE	(103)
+
+#define IMAGE_SYM_TYPE \
+  ((IMAGE_SYM_DTYPE_NULL << 4) | IMAGE_SYM_TYPE_NULL)
+
+#define C_STAT		(3)
+#define C_FILE		(103)
+
+/* Private data for an simple_object_read.  */
+
+struct simple_object_xcoff_read
+{
+  /* Magic number.  */
+  unsigned short magic;
+  /* Number of sections.  */
+  unsigned short nscns;
+  /* File offset of symbol table.  */
+  off_t symptr;
+  /* Number of symbol table entries.  */
+  unsigned int nsyms;
+  /* Flags.  */
+  unsigned short flags;
+  /* Offset of section headers in file.  */
+  off_t scnhdr_offset;
+};
+
+/* Private data for an simple_object_attributes.  */
+
+struct simple_object_xcoff_attributes
+{
+  /* Magic number.  */
+  unsigned short magic;
+  /* Flags.  */
+  unsigned short flags;
+};
+
+/* See if we have a XCOFF file.  */
+
+static void *
+simple_object_xcoff_match (unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN],
+			   int descriptor, off_t offset,
+			   const char *segment_name ATTRIBUTE_UNUSED,
+			   const char **errmsg, int *err)
+{
+  unsigned short magic;
+  unsigned short (*fetch_16) (const unsigned char *);
+  unsigned int (*fetch_32) (const unsigned char *);
+  ulong_type (*fetch_64) (const unsigned char *);
+  unsigned char hdrbuf[sizeof (struct external_filehdr)];
+  struct simple_object_xcoff_read *ocr;
+  int u64;
+
+  magic = simple_object_fetch_big_16 (header);
+
+  if (magic != U802TOCMAGIC && magic != U64_TOCMAGIC)
+    {
+      *errmsg = NULL;
+      *err = 0;
+      return NULL;
+    }
+
+  fetch_16 = simple_object_fetch_big_16;
+  fetch_32 = simple_object_fetch_big_32;
+  fetch_64 = simple_object_fetch_big_64;
+
+  if (!simple_object_internal_read (descriptor, offset, hdrbuf, sizeof hdrbuf,
+				    errmsg, err))
+    return NULL;
+
+  u64 = magic == U64_TOCMAGIC;
+
+  ocr = XNEW (struct simple_object_xcoff_read);
+  ocr->magic = magic;
+  ocr->nscns = fetch_16 (hdrbuf + offsetof (struct external_filehdr, f_nscns));
+  if (u64)
+    {
+      ocr->symptr = fetch_64 (hdrbuf
+			      + offsetof (struct external_filehdr,
+					  u.xcoff64.f_symptr));
+      ocr->nsyms = fetch_32 (hdrbuf + offsetof (struct external_filehdr,
+						u.xcoff64.f_nsyms));
+      ocr->scnhdr_offset = (sizeof (struct external_filehdr)
+			    + fetch_16 (hdrbuf + offsetof (struct external_filehdr,
+							   u.xcoff64.f_opthdr)));
+
+    }
+  else
+    {
+      ocr->symptr = fetch_32 (hdrbuf
+			      + offsetof (struct external_filehdr,
+					  u.xcoff32.f_symptr));
+      ocr->nsyms = fetch_32 (hdrbuf + offsetof (struct external_filehdr,
+						u.xcoff32.f_nsyms));
+      ocr->scnhdr_offset = (sizeof (struct external_filehdr) - 4
+			    + fetch_16 (hdrbuf + offsetof (struct external_filehdr,
+							   u.xcoff32.f_opthdr)));
+
+    }
+
+  return (void *) ocr;
+}
+
+/* Read the string table in a XCOFF file.  */
+
+static char *
+simple_object_xcoff_read_strtab (simple_object_read *sobj, size_t *strtab_size,
+				 const char **errmsg, int *err)
+{
+  struct simple_object_xcoff_read *ocr =
+    (struct simple_object_xcoff_read *) sobj->data;
+  off_t strtab_offset;
+  unsigned char strsizebuf[4];
+  size_t strsize;
+  char *strtab;
+
+  strtab_offset = sobj->offset + ocr->symptr
+    + ocr->nsyms * SYMESZ;
+  if (!simple_object_internal_read (sobj->descriptor, strtab_offset,
+				    strsizebuf, 4, errmsg, err))
+    return NULL;
+  strsize = simple_object_fetch_big_32 (strsizebuf);
+  strtab = XNEWVEC (char, strsize);
+  if (!simple_object_internal_read (sobj->descriptor, strtab_offset,
+				    (unsigned char *) strtab, strsize, errmsg,
+				    err))
+    {
+      XDELETEVEC (strtab);
+      return NULL;
+    }
+  *strtab_size = strsize;
+  return strtab;
+}
+
+/* Find all sections in a XCOFF file.  */
+
+static const char *
+simple_object_xcoff_find_sections (simple_object_read *sobj,
+				  int (*pfn) (void *, const char *,
+					      off_t offset, off_t length),
+				  void *data,
+				  int *err)
+{
+  struct simple_object_xcoff_read *ocr =
+    (struct simple_object_xcoff_read *) sobj->data;
+  int u64 = ocr->magic == U64_TOCMAGIC;
+  size_t scnhdr_size;
+  unsigned char *scnbuf;
+  const char *errmsg;
+  unsigned int (*fetch_32) (const unsigned char *);
+  ulong_type (*fetch_64) (const unsigned char *);
+  unsigned int nscns;
+  char *strtab;
+  size_t strtab_size;
+  unsigned int i;
+
+  scnhdr_size = u64 ? SCNHSZ64 : SCNHSZ32;
+  scnbuf = XNEWVEC (unsigned char, scnhdr_size * ocr->nscns);
+  if (!simple_object_internal_read (sobj->descriptor,
+				    sobj->offset + ocr->scnhdr_offset,
+				    scnbuf, scnhdr_size * ocr->nscns, &errmsg,
+				    err))
+    {
+      XDELETEVEC (scnbuf);
+      return errmsg;
+    }
+
+  fetch_32 = simple_object_fetch_big_32;
+  fetch_64 = simple_object_fetch_big_64;
+
+  nscns = ocr->nscns;
+  strtab = NULL;
+  strtab_size = 0;
+  for (i = 0; i < nscns; ++i)
+    {
+      unsigned char *scnhdr;
+      unsigned char *scnname;
+      char namebuf[SCNNMLEN + 1];
+      char *name;
+      off_t scnptr;
+      unsigned int size;
+
+      scnhdr = scnbuf + i * scnhdr_size;
+      scnname = scnhdr + offsetof (struct external_scnhdr, s_name);
+      memcpy (namebuf, scnname, SCNNMLEN);
+      namebuf[SCNNMLEN] = '\0';
+      name = &namebuf[0];
+      if (namebuf[0] == '/')
+	{
+	  size_t strindex;
+	  char *end;
+
+	  strindex = strtol (namebuf + 1, &end, 10);
+	  if (*end == '\0')
+	    {
+	      /* The real section name is found in the string
+		 table.  */
+	      if (strtab == NULL)
+		{
+		  strtab = simple_object_xcoff_read_strtab (sobj,
+							   &strtab_size,
+							   &errmsg, err);
+		  if (strtab == NULL)
+		    {
+		      XDELETEVEC (scnbuf);
+		      return errmsg;
+		    }
+		}
+
+	      if (strindex < 4 || strindex >= strtab_size)
+		{
+		  XDELETEVEC (strtab);
+		  XDELETEVEC (scnbuf);
+		  *err = 0;
+		  return "section string index out of range";
+		}
+
+	      name = strtab + strindex;
+	    }
+	}
+
+      if (u64)
+	{
+	  scnptr = fetch_64 (scnhdr + offsetof (struct external_scnhdr,
+						u.xcoff64.s_scnptr));
+	  size = fetch_64 (scnhdr + offsetof (struct external_scnhdr,
+					      u.xcoff64.s_size));
+	}
+      else
+	{
+	  scnptr = fetch_32 (scnhdr + offsetof (struct external_scnhdr,
+						u.xcoff32.s_scnptr));
+	  size = fetch_32 (scnhdr + offsetof (struct external_scnhdr,
+					      u.xcoff32.s_size));
+	}
+
+      if (!(*pfn) (data, name, scnptr, size))
+	break;
+    }
+
+  if (strtab != NULL)
+    XDELETEVEC (strtab);
+  XDELETEVEC (scnbuf);
+
+  return NULL;
+}
+
+/* Fetch the attributes for an simple_object_read.  */
+
+static void *
+simple_object_xcoff_fetch_attributes (simple_object_read *sobj,
+				     const char **errmsg ATTRIBUTE_UNUSED,
+				     int *err ATTRIBUTE_UNUSED)
+{
+  struct simple_object_xcoff_read *ocr =
+    (struct simple_object_xcoff_read *) sobj->data;
+  struct simple_object_xcoff_attributes *ret;
+
+  ret = XNEW (struct simple_object_xcoff_attributes);
+  ret->magic = ocr->magic;
+  ret->flags = ocr->flags;
+  return ret;
+}
+
+/* Release the private data for an simple_object_read.  */
+
+static void
+simple_object_xcoff_release_read (void *data)
+{
+  XDELETE (data);
+}
+
+/* Compare two attributes structures.  */
+
+static const char *
+simple_object_xcoff_attributes_merge (void *todata, void *fromdata, int *err)
+{
+  struct simple_object_xcoff_attributes *to =
+    (struct simple_object_xcoff_attributes *) todata;
+  struct simple_object_xcoff_attributes *from =
+    (struct simple_object_xcoff_attributes *) fromdata;
+
+  if (to->magic != from->magic)
+    {
+      *err = 0;
+      return "XCOFF object format mismatch";
+    }
+  return NULL;
+}
+
+/* Release the private data for an attributes structure.  */
+
+static void
+simple_object_xcoff_release_attributes (void *data)
+{
+  XDELETE (data);
+}
+
+/* Prepare to write out a file.  */
+
+static void *
+simple_object_xcoff_start_write (void *attributes_data,
+				const char **errmsg ATTRIBUTE_UNUSED,
+				int *err ATTRIBUTE_UNUSED)
+{
+  struct simple_object_xcoff_attributes *attrs =
+    (struct simple_object_xcoff_attributes *) attributes_data;
+  struct simple_object_xcoff_attributes *ret;
+
+  /* We're just going to record the attributes, but we need to make a
+     copy because the user may delete them.  */
+  ret = XNEW (struct simple_object_xcoff_attributes);
+  *ret = *attrs;
+  return ret;
+}
+
+/* Write out a XCOFF filehdr.  */
+
+static int
+simple_object_xcoff_write_filehdr (simple_object_write *sobj, int descriptor,
+				  unsigned int nscns, size_t symtab_offset,
+				  unsigned int nsyms, const char **errmsg,
+				  int *err)
+{
+  struct simple_object_xcoff_attributes *attrs =
+    (struct simple_object_xcoff_attributes *) sobj->data;
+  int u64 = attrs->magic == U64_TOCMAGIC;
+  unsigned char hdrbuf[sizeof (struct external_filehdr)];
+  unsigned char *hdr;
+  void (*set_16) (unsigned char *, unsigned short);
+  void (*set_32) (unsigned char *, unsigned int);
+  void (*set_64) (unsigned char *, ulong_type);
+
+  hdr = &hdrbuf[0];
+
+  set_16 = simple_object_set_big_16;
+  set_32 = simple_object_set_big_32;
+  set_64 = simple_object_set_big_64;
+
+  memset (hdr, 0, sizeof (struct external_filehdr));
+
+  set_16 (hdr + offsetof (struct external_filehdr, f_magic), attrs->magic);
+  set_16 (hdr + offsetof (struct external_filehdr, f_nscns), nscns);
+  /* f_timdat left as zero.  */
+  if (u64)
+    {
+      set_64 (hdr + offsetof (struct external_filehdr, u.xcoff64.f_symptr),
+	      symtab_offset);
+      set_32 (hdr + offsetof (struct external_filehdr, u.xcoff64.f_nsyms),
+	      nsyms);
+      /* f_opthdr left as zero.  */
+      set_16 (hdr + offsetof (struct external_filehdr, u.xcoff64.f_flags),
+	      attrs->flags);
+    }
+  else
+    {
+      set_32 (hdr + offsetof (struct external_filehdr, u.xcoff64.f_symptr),
+	      symtab_offset);
+      set_32 (hdr + offsetof (struct external_filehdr, u.xcoff64.f_nsyms),
+	      nsyms);
+      /* f_opthdr left as zero.  */
+      set_16 (hdr + offsetof (struct external_filehdr, u.xcoff64.f_flags),
+	      attrs->flags);
+    }
+
+  return simple_object_internal_write (descriptor, 0, hdrbuf,
+				       sizeof (struct external_filehdr),
+				       errmsg, err);
+}
+
+/* Write out a XCOFF section header.  */
+
+static int
+simple_object_xcoff_write_scnhdr (simple_object_write *sobj,
+				  int descriptor,
+				  const char *name, size_t *name_offset,
+				  off_t scnhdr_offset, size_t scnsize,
+				  off_t offset, unsigned int align,
+				  const char **errmsg, int *err)
+{
+  struct simple_object_xcoff_read *ocr =
+    (struct simple_object_xcoff_read *) sobj->data;
+  int u64 = ocr->magic == U64_TOCMAGIC;
+  void (*set_32) (unsigned char *, unsigned int);
+  void (*set_64) (unsigned char *, unsigned int);
+  unsigned char hdrbuf[sizeof (struct external_scnhdr)];
+  unsigned char *hdr;
+  size_t namelen;
+  unsigned int flags;
+
+  set_32 = simple_object_set_big_32;
+  set_64 = simple_object_set_big_32;
+
+  memset (hdrbuf, 0, sizeof hdrbuf);
+  hdr = &hdrbuf[0];
+
+  namelen = strlen (name);
+  if (namelen <= SCNNMLEN)
+    strncpy ((char *) hdr + offsetof (struct external_scnhdr, s_name),
+	     name, SCNNMLEN);
+  else
+    {
+      snprintf ((char *) hdr + offsetof (struct external_scnhdr, s_name),
+		SCNNMLEN, "/%lu", (unsigned long) *name_offset);
+      *name_offset += namelen + 1;
+    }
+
+  /* s_paddr left as zero.  */
+  /* s_vaddr left as zero.  */
+  if (u64)
+    {
+      set_64 (hdr + offsetof (struct external_scnhdr, u.xcoff64.s_size),
+	      scnsize);
+      set_64 (hdr + offsetof (struct external_scnhdr, u.xcoff64.s_scnptr),
+	      offset);
+    }
+  else
+    {
+      set_32 (hdr + offsetof (struct external_scnhdr, u.xcoff32.s_size),
+	      scnsize);
+      set_32 (hdr + offsetof (struct external_scnhdr, u.xcoff32.s_scnptr),
+	      offset);
+    }
+  /* s_relptr left as zero.  */
+  /* s_lnnoptr left as zero.  */
+  /* s_nreloc left as zero.  */
+  /* s_nlnno left as zero.  */
+  flags = STYP_DATA;
+  if (align > 13)
+    align = 13;
+  if (u64)
+    set_32 (hdr + offsetof (struct external_scnhdr, u.xcoff64.s_flags), flags);
+  else
+    set_32 (hdr + offsetof (struct external_scnhdr, u.xcoff32.s_flags), flags);
+
+  return simple_object_internal_write (descriptor, scnhdr_offset, hdrbuf,
+				       u64 ? SCNHSZ64 : SCNHSZ32,
+				       errmsg, err);
+}
+
+/* Write out a complete XCOFF file.  */
+
+static const char *
+simple_object_xcoff_write_to_file (simple_object_write *sobj, int descriptor,
+				  int *err)
+{
+  struct simple_object_xcoff_read *ocr =
+    (struct simple_object_xcoff_read *) sobj->data;
+  int u64 = ocr->magic == U64_TOCMAGIC;
+  unsigned int nscns, secnum;
+  simple_object_write_section *section;
+  off_t scnhdr_offset;
+  size_t symtab_offset;
+  off_t secsym_offset;
+  unsigned int nsyms;
+  size_t offset;
+  size_t name_offset;
+  const char *errmsg;
+  unsigned char strsizebuf[4];
+  /* The interface doesn't give us access to the name of the input file
+     yet.  We want to use its basename for the FILE symbol.  This is
+     what 'gas' uses when told to assemble from stdin.  */
+  const char *source_filename = "fake";
+  size_t sflen;
+  union
+  {
+    struct external_syment sym;
+    union external_auxent aux;
+  } syms[2];
+  void (*set_16) (unsigned char *, unsigned short);
+  void (*set_32) (unsigned char *, unsigned int);
+
+  set_16 = simple_object_set_big_16;
+  set_32 = simple_object_set_big_32;
+
+  nscns = 0;
+  for (section = sobj->sections; section != NULL; section = section->next)
+    ++nscns;
+
+  scnhdr_offset = sizeof (struct external_filehdr) - (u64 ? 4 : 0);
+  offset = scnhdr_offset + nscns * (u64 ? SCNHSZ64 : SCNHSZ32);
+  name_offset = 4;
+  for (section = sobj->sections; section != NULL; section = section->next)
+    {
+      size_t mask;
+      size_t new_offset;
+      size_t scnsize;
+      struct simple_object_write_section_buffer *buffer;
+
+      mask = (1U << section->align) - 1;
+      new_offset = offset & mask;
+      new_offset &= ~ mask;
+      while (new_offset > offset)
+	{
+	  unsigned char zeroes[16];
+	  size_t write;
+
+	  memset (zeroes, 0, sizeof zeroes);
+	  write = new_offset - offset;
+	  if (write > sizeof zeroes)
+	    write = sizeof zeroes;
+	  if (!simple_object_internal_write (descriptor, offset, zeroes, write,
+					     &errmsg, err))
+	    return errmsg;
+	}
+
+      scnsize = 0;
+      for (buffer = section->buffers; buffer != NULL; buffer = buffer->next)
+	{
+	  if (!simple_object_internal_write (descriptor, offset + scnsize,
+					     ((const unsigned char *)
+					      buffer->buffer),
+					     buffer->size, &errmsg, err))
+	    return errmsg;
+	  scnsize += buffer->size;
+	}
+
+      if (!simple_object_xcoff_write_scnhdr (sobj, descriptor, section->name,
+					    &name_offset, scnhdr_offset,
+					    scnsize, offset, section->align,
+					    &errmsg, err))
+	return errmsg;
+
+      scnhdr_offset += u64 ? SCNHSZ64 : SCNHSZ32;
+      offset += scnsize;
+    }
+
+  /* Symbol table is always half-word aligned.  */
+  offset += (offset & 1);
+  /* There is a file symbol and a section symbol per section,
+     and each of these has a single auxiliary symbol following.  */
+  nsyms = 2 * (nscns + 1);
+  symtab_offset = offset;
+  /* Advance across space reserved for symbol table to locate
+     start of string table.  */
+  offset += nsyms * SYMESZ;
+
+  /* Write out file symbol.  */
+  memset (&syms[0], 0, sizeof (syms));
+  if (!u64)
+    strcpy ((char *)&syms[0].sym.u.xcoff32.n.n_name[0], ".file");
+  set_16 (&syms[0].sym.n_scnum[0], N_DEBUG);
+  set_16 (&syms[0].sym.n_type[0], IMAGE_SYM_TYPE);
+  syms[0].sym.n_sclass[0] = C_FILE;
+  syms[0].sym.n_numaux[0] = 1;
+  /* The name need not be nul-terminated if it fits into the x_fname field
+     directly, but must be if it has to be placed into the string table.  */
+  sflen = strlen (source_filename);
+  if (sflen <= FILNMLEN)
+    memcpy (&syms[1].aux.x_file.x_fname[0], source_filename, sflen);
+  else
+    {
+      set_32 (&syms[1].aux.x_file._x.x_offset[0], name_offset);
+      if (!simple_object_internal_write (descriptor, offset + name_offset,
+					 ((const unsigned char *)
+					  source_filename),
+					 sflen + 1, &errmsg, err))
+	return errmsg;
+      name_offset += strlen (source_filename) + 1;
+    }
+  if (!simple_object_internal_write (descriptor, symtab_offset,
+				     (const unsigned char *) &syms[0],
+				     sizeof (syms), &errmsg, err))
+    return errmsg;
+
+  /* Write the string table length, followed by the strings and section
+     symbols in step with each other.  */
+  set_32 (strsizebuf, name_offset);
+  if (!simple_object_internal_write (descriptor, offset, strsizebuf, 4,
+				     &errmsg, err))
+    return errmsg;
+
+  name_offset = 4;
+  secsym_offset = symtab_offset + sizeof (syms);
+  memset (&syms[0], 0, sizeof (syms));
+  set_16 (&syms[0].sym.n_type[0], IMAGE_SYM_TYPE);
+  syms[0].sym.n_sclass[0] = C_STAT;
+  syms[0].sym.n_numaux[0] = 1;
+  secnum = 1;
+
+  for (section = sobj->sections; section != NULL; section = section->next)
+    {
+      size_t namelen;
+      size_t scnsize;
+      struct simple_object_write_section_buffer *buffer;
+
+      namelen = strlen (section->name);
+      set_16 (&syms[0].sym.n_scnum[0], secnum++);
+      scnsize = 0;
+      for (buffer = section->buffers; buffer != NULL; buffer = buffer->next)
+	scnsize += buffer->size;
+      set_32 (&syms[1].aux.x_scn.x_scnlen[0], scnsize);
+      if (namelen > SCNNMLEN)
+	{
+	  set_32 (&syms[0].sym.u.xcoff32.n.n.n_zeroes[0], 0);
+	  set_32 (&syms[0].sym.u.xcoff32.n.n.n_offset[0], name_offset);
+	  if (!simple_object_internal_write (descriptor, offset + name_offset,
+					     ((const unsigned char *)
+					      section->name),
+					     namelen + 1, &errmsg, err))
+	    return errmsg;
+	  name_offset += namelen + 1;
+	}
+      else
+	{
+	  memcpy (&syms[0].sym.u.xcoff32.n.n_name[0], section->name,
+		  strlen (section->name));
+	  memset (&syms[0].sym.u.xcoff32.n.n_name[strlen (section->name)], 0,
+		  N_SYMNMLEN - strlen (section->name));
+	}
+
+      if (!simple_object_internal_write (descriptor, secsym_offset,
+					 (const unsigned char *) &syms[0],
+					 sizeof (syms), &errmsg, err))
+	return errmsg;
+      secsym_offset += sizeof (syms);
+    }
+
+  if (!simple_object_xcoff_write_filehdr (sobj, descriptor, nscns,
+					 symtab_offset, nsyms, &errmsg, err))
+    return errmsg;
+
+  return NULL;
+}
+
+/* Release the private data for an simple_object_write structure.  */
+
+static void
+simple_object_xcoff_release_write (void *data)
+{
+  XDELETE (data);
+}
+
+/* The XCOFF functions.  */
+
+const struct simple_object_functions simple_object_xcoff_functions =
+{
+  simple_object_xcoff_match,
+  simple_object_xcoff_find_sections,
+  simple_object_xcoff_fetch_attributes,
+  simple_object_xcoff_release_read,
+  simple_object_xcoff_attributes_merge,
+  simple_object_xcoff_release_attributes,
+  simple_object_xcoff_start_write,
+  simple_object_xcoff_write_to_file,
+  simple_object_xcoff_release_write
+};