Add support for generating and inserting build IDs into COFF binaries.

	* peXXigen.c (pe_print_debugdata): New function: Displays the
	contents of the debug directory and decodes codeview entries.
	(_bfd_XXi_swap_debugdir_in, _bfd_XXi_swap_debugdir_out)
	(_bfd_XXi_slurp_codeview_record, _bfd_XXi_write_codeview_record):
	Add functions for reading and writing debugdir and codeview
	records.
	* libpei.h (_bfd_XXi_swap_debugdir_in, _bfd_XXi_swap_debugdir_out)
	(_bfd_XXi_write_codeview_record): Add prototypes and macros.
	* libcoff-in.h (pe_tdata): Add build-id data.
	* libcoff.h: Regenerate.
	* coffcode.h (coff_write_object_contents): Run build_id
	after_write_object_contents hook.

	* pe.h (external_IMAGE_DEBUG_DIRECTORY, _CV_INFO_PDB70)
	(_CV_INFO_PDB20): Add structures and constants for debug directory
	and codeview records.
	* internal.h (internal_IMAGE_DEBUG_DIRECTORY, CODEVIEW_INFO):
	Add structures and constants for internal representation of debug
	directory and codeview records.

	* emultempl/elf32.em (id_note_section_size, read_hex, write_build_id):
	Move code for parsing build-id option and calculating the build-id to...
	* ldbuildid.c: New file.
	* ldbuildid.h: New file.
	* Makefile.am (CFILES, HFILES, OFILES, ld_new_SOURCES): Add new
	files.
	* Makefile.in: Regenerate.
	* ld.texinfo: Update --build-id description to mention COFF
	support.
	* NEWS: Mention support for COFF build ids.
	* emultempl/pe.em (gld${EMULATION_NAME}_handle_option):
	(pecoff_checksum_contents, write_build_id, setup_build_id)
	(gld_${EMULATION_NAME}_after_open):  Handle and implement
	build-id option.
	* emultempl/pep.em: Likewise.

3 files changed, 447 insertions, 116 deletions

diff --git a/ld/emultempl/elf32.em b/ld/emultempl/elf32.em
index de460a2..0173b66 100644
--- a/ld/emultempl/elf32.em
+++ b/ld/emultempl/elf32.em
@@ -39,10 +39,7 @@ fragment <<EOF
 #include "bfd.h"
 #include "libiberty.h"
 #include "filenames.h"
-#include "safe-ctype.h"
 #include "getopt.h"
-#include "md5.h"
-#include "sha1.h"
 #include <fcntl.h>
 
 #include "bfdlink.h"
@@ -54,6 +51,7 @@ fragment <<EOF
 #include "ldlang.h"
 #include "ldfile.h"
 #include "ldemul.h"
+#include "ldbuildid.h"
 #include <ldgram.h>
 #include "elf/common.h"
 #include "elf-bfd.h"
@@ -895,53 +893,20 @@ id_note_section_size (bfd *abfd ATTRIBUTE_UNUSED)
 {
   const char *style = emit_note_gnu_build_id;
   bfd_size_type size;
+  bfd_size_type build_id_size;
 
   size = offsetof (Elf_External_Note, name[sizeof "GNU"]);
   size = (size + 3) & -(bfd_size_type) 4;
 
-  if (!strcmp (style, "md5") || !strcmp (style, "uuid"))
-    size += 128 / 8;
-  else if (!strcmp (style, "sha1"))
-    size += 160 / 8;
-  else if (!strncmp (style, "0x", 2))
-    {
-      /* ID is in string form (hex).  Convert to bits.  */
-      const char *id = style + 2;
-      do
-	{
-	  if (ISXDIGIT (id[0]) && ISXDIGIT (id[1]))
-	    {
-	      ++size;
-	      id += 2;
-	    }
-	  else if (*id == '-' || *id == ':')
-	    ++id;
-	  else
-	    {
-	      size = 0;
-	      break;
-	    }
-	} while (*id != '\0');
-    }
+  build_id_size = compute_build_id_size (style);
+  if (build_id_size)
+    size += build_id_size;
   else
     size = 0;
 
   return size;
 }
 
-static unsigned char
-read_hex (const char xdigit)
-{
-  if (ISDIGIT (xdigit))
-    return xdigit - '0';
-  if (ISUPPER (xdigit))
-    return xdigit - 'A' + 0xa;
-  if (ISLOWER (xdigit))
-    return xdigit - 'a' + 0xa;
-  abort ();
-  return 0;
-}
-
 static bfd_boolean
 write_build_id (bfd *abfd)
 {
@@ -954,7 +919,6 @@ write_build_id (bfd *abfd)
   bfd_size_type size;
   file_ptr position;
   Elf_External_Note *e_note;
-  typedef void (*sum_fn) (const void *, size_t, void *);
 
   style = t->o->build_id.style;
   asec = t->o->build_id.sec;
@@ -986,55 +950,7 @@ write_build_id (bfd *abfd)
   bfd_h_put_32 (abfd, NT_GNU_BUILD_ID, &e_note->type);
   memcpy (e_note->name, "GNU", sizeof "GNU");
 
-  if (strcmp (style, "md5") == 0)
-    {
-      struct md5_ctx ctx;
-
-      md5_init_ctx (&ctx);
-      if (!bed->s->checksum_contents (abfd, (sum_fn) &md5_process_bytes, &ctx))
-	return FALSE;
-      md5_finish_ctx (&ctx, id_bits);
-    }
-  else if (strcmp (style, "sha1") == 0)
-    {
-      struct sha1_ctx ctx;
-
-      sha1_init_ctx (&ctx);
-      if (!bed->s->checksum_contents (abfd, (sum_fn) &sha1_process_bytes, &ctx))
-	return FALSE;
-      sha1_finish_ctx (&ctx, id_bits);
-    }
-  else if (strcmp (style, "uuid") == 0)
-    {
-      int n;
-      int fd = open ("/dev/urandom", O_RDONLY);
-      if (fd < 0)
-	return FALSE;
-      n = read (fd, id_bits, size);
-      close (fd);
-      if (n < (int) size)
-	return FALSE;
-    }
-  else if (strncmp (style, "0x", 2) == 0)
-    {
-      /* ID is in string form (hex).  Convert to bits.  */
-      const char *id = style + 2;
-      size_t n = 0;
-      do
-	{
-	  if (ISXDIGIT (id[0]) && ISXDIGIT (id[1]))
-	    {
-	      id_bits[n] = read_hex (*id++) << 4;
-	      id_bits[n++] |= read_hex (*id++);
-	    }
-	  else if (*id == '-' || *id == ':')
-	    ++id;
-	  else
-	    abort ();		/* Should have been validated earlier.  */
-	} while (*id != '\0');
-    }
-  else
-    abort ();			/* Should have been validated earlier.  */
+  generate_build_id (abfd, style, bed->s->checksum_contents, id_bits, size);
 
   position = i_shdr->sh_offset + asec->output_offset;
   size = asec->size;
diff --git a/ld/emultempl/pe.em b/ld/emultempl/pe.em
index c18cb26..ba51cc0 100644
--- a/ld/emultempl/pe.em
+++ b/ld/emultempl/pe.em
@@ -66,6 +66,7 @@ fragment <<EOF
 #include "ldlex.h"
 #include "ldmisc.h"
 #include "ldctor.h"
+#include "ldbuildid.h"
 #include "coff/internal.h"
 
 /* FIXME: See bfd/peXXigen.c for why we include an architecture specific
@@ -73,9 +74,10 @@ fragment <<EOF
 #include "coff/i386.h"
 #include "coff/pe.h"
 
-/* FIXME: This is a BFD internal header file, and we should not be
+/* FIXME: These are BFD internal header files, and we should not be
    using it here.  */
 #include "../bfd/libcoff.h"
+#include "../bfd/libpei.h"
 
 #include "deffile.h"
 #include "pe-dll.h"
@@ -131,6 +133,7 @@ static char * thumb_entry_symbol = NULL;
 static lang_assignment_statement_type *image_base_statement = 0;
 static unsigned short pe_dll_characteristics = 0;
 static bfd_boolean insert_timestamp = FALSE;
+static const char *emit_build_id;
 
 #ifdef DLL_SUPPORT
 static int pe_enable_stdcall_fixup = -1; /* 0=disable 1=enable.  */
@@ -269,6 +272,7 @@ fragment <<EOF
 #define OPTION_TERMINAL_SERVER_AWARE	(OPTION_WDM_DRIVER + 1)
 /* Determinism.  */
 #define OPTION_INSERT_TIMESTAMP		(OPTION_TERMINAL_SERVER_AWARE + 1)
+#define OPTION_BUILD_ID			(OPTION_INSERT_TIMESTAMP + 1)
 
 static void
 gld${EMULATION_NAME}_add_options
@@ -347,6 +351,7 @@ gld${EMULATION_NAME}_add_options
     {"no-bind", no_argument, NULL, OPTION_NO_BIND},
     {"wdmdriver", no_argument, NULL, OPTION_WDM_DRIVER},
     {"tsaware", no_argument, NULL, OPTION_TERMINAL_SERVER_AWARE},
+    {"build-id", optional_argument, NULL, OPTION_BUILD_ID},
     {NULL, no_argument, NULL, 0}
   };
 
@@ -386,7 +391,7 @@ typedef struct
 #define U_SIZE(CSTR) \
   (sizeof (CSTR) + (is_underscoring () == 0 ? 0 : 1))
 
-#define D(field,symbol,def,usc)  {&pe.field,sizeof(pe.field), def, symbol, 0, usc}
+#define D(field,symbol,def,usc)  {&pe.field, sizeof (pe.field), def, symbol, 0, usc}
 
 static definfo init[] =
 {
@@ -495,6 +500,7 @@ gld_${EMULATION_NAME}_list_options (FILE *file)
   fprintf (file, _("  --no-bind			 Do not bind this image\n"));
   fprintf (file, _("  --wdmdriver		 Driver uses the WDM model\n"));
   fprintf (file, _("  --tsaware                  Image is Terminal Server aware\n"));
+  fprintf (file, _("  --build-id[=STYLE]         Generate build ID\n"));
 }
 
 
@@ -689,6 +695,7 @@ set_pe_stack_heap (char *resname, char *comname)
     einfo (_("%P%F: strange hex info for PE parameter '%s'\n"), optarg);
 }
 
+#define DEFAULT_BUILD_ID_STYLE	"md5"
 
 static bfd_boolean
 gld${EMULATION_NAME}_handle_option (int optc)
@@ -807,7 +814,7 @@ gld${EMULATION_NAME}_handle_option (int optc)
       if (optarg && *optarg)
 	{
 	  char *end;
-	  pe_auto_image_base = strtoul(optarg, &end, 0);
+	  pe_auto_image_base = strtoul (optarg, &end, 0);
 	  /* XXX should check that we actually parsed something */
 	}
       break;
@@ -880,6 +887,17 @@ gld${EMULATION_NAME}_handle_option (int optc)
     case OPTION_TERMINAL_SERVER_AWARE:
       pe_dll_characteristics |= IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE;
       break;
+    case OPTION_BUILD_ID:
+      if (emit_build_id != NULL)
+	{
+	  free ((char *) emit_build_id);
+	  emit_build_id = NULL;
+	}
+      if (optarg == NULL)
+	optarg = DEFAULT_BUILD_ID_STYLE;
+      if (strcmp (optarg, "none"))
+	emit_build_id = xstrdup (optarg);
+      break;
     }
 
   /*  Set DLLCharacteristics bits  */
@@ -1235,6 +1253,169 @@ debug_section_p (bfd *abfd ATTRIBUTE_UNUSED, asection *sect, void *obj)
     *found = 1;
 }
 
+static bfd_boolean
+pecoff_checksum_contents (bfd *abfd,
+			  void (*process) (const void *, size_t, void *),
+			  void *arg)
+{
+  file_ptr filepos = (file_ptr) 0;
+
+  while (1)
+    {
+      unsigned char b;
+      int status;
+
+      if (bfd_seek (abfd, filepos, SEEK_SET) != 0)
+	return 0;
+
+      status = bfd_bread (&b, (bfd_size_type) 1, abfd);
+      if (status < 1)
+        {
+          break;
+        }
+
+      (*process) (&b, 1, arg);
+      filepos += 1;
+    }
+
+  return TRUE;
+}
+
+static bfd_boolean
+write_build_id (bfd *abfd)
+{
+  struct pe_tdata *t = pe_data (abfd);
+  asection *asec;
+  struct bfd_link_order *link_order = NULL;
+  unsigned char *contents;
+  bfd_size_type size;
+  bfd_size_type build_id_size;
+  unsigned char *build_id;
+
+  /* Find the section the .build-id output section has been merged info.  */
+  for (asec = abfd->sections; asec != NULL; asec = asec->next)
+    {
+      struct bfd_link_order *l = NULL;
+      for (l = asec->map_head.link_order; l != NULL; l = l->next)
+        {
+          if ((l->type == bfd_indirect_link_order))
+            {
+              if (l->u.indirect.section == t->build_id.sec)
+                {
+                  link_order = l;
+                  break;
+                }
+            }
+        }
+
+      if (link_order)
+        break;
+    }
+
+  if (!link_order)
+    {
+      einfo (_("%P: warning: .build-id section discarded,"
+               " --build-id ignored.\n"));
+      return TRUE;
+    }
+
+  if (t->build_id.sec->contents == NULL)
+    t->build_id.sec->contents = (unsigned char *) xmalloc (t->build_id.sec->size);
+  contents = t->build_id.sec->contents;
+  size = t->build_id.sec->size;
+
+  build_id_size = compute_build_id_size (t->build_id.style);
+  build_id = xmalloc (build_id_size);
+  generate_build_id (abfd, t->build_id.style, pecoff_checksum_contents, build_id, build_id_size);
+
+  bfd_vma ib = pe_data (link_info.output_bfd)->pe_opthdr.ImageBase;
+
+  /* Construct a debug directory entry which points to an immediately following CodeView record.  */
+  struct internal_IMAGE_DEBUG_DIRECTORY idd;
+  idd.Characteristics = 0;
+  idd.TimeDateStamp = 0;
+  idd.MajorVersion = 0;
+  idd.MinorVersion = 0;
+  idd.Type = PE_IMAGE_DEBUG_TYPE_CODEVIEW;
+  idd.SizeOfData = sizeof (CV_INFO_PDB70) + 1;
+  idd.AddressOfRawData = asec->vma - ib + link_order->offset
+    + sizeof (struct external_IMAGE_DEBUG_DIRECTORY);
+  idd.PointerToRawData = asec->filepos + link_order->offset
+    + sizeof (struct external_IMAGE_DEBUG_DIRECTORY);
+
+  struct external_IMAGE_DEBUG_DIRECTORY *ext = (struct external_IMAGE_DEBUG_DIRECTORY *)contents;
+  _bfd_XXi_swap_debugdir_out (abfd, &idd, ext);
+
+  /* Write the debug directory entry.  */
+  if (bfd_seek (abfd, asec->filepos + link_order->offset, SEEK_SET) != 0)
+    return 0;
+
+  if ((bfd_bwrite (contents, size, abfd) != size))
+    return 0;
+
+  /* Construct the CodeView record.  */
+  CODEVIEW_INFO cvinfo;
+  cvinfo.CVSignature = CVINFO_PDB70_CVSIGNATURE;
+  cvinfo.Age = 1;
+
+  /* Zero pad or truncate the generated build_id to fit in the CodeView record.  */
+  memset (&(cvinfo.Signature), 0, CV_INFO_SIGNATURE_LENGTH);
+  memcpy (&(cvinfo.Signature), build_id, (build_id_size > CV_INFO_SIGNATURE_LENGTH)
+	  ? CV_INFO_SIGNATURE_LENGTH :  build_id_size);
+
+  free (build_id);
+
+  /* Write the codeview record.  */
+  if (_bfd_XXi_write_codeview_record (abfd, idd.PointerToRawData, &cvinfo) == 0)
+    return 0;
+
+  /* Record the location of the debug directory in the data directory.  */
+  pe_data (link_info.output_bfd)->pe_opthdr.DataDirectory[PE_DEBUG_DATA].VirtualAddress
+    = asec->vma  - ib + link_order->offset;
+  pe_data (link_info.output_bfd)->pe_opthdr.DataDirectory[PE_DEBUG_DATA].Size
+    = sizeof (struct external_IMAGE_DEBUG_DIRECTORY);
+
+  return TRUE;
+}
+
+/* Make .build-id section, and set up coff_tdata->build_id. */
+static bfd_boolean
+setup_build_id (bfd *ibfd)
+{
+  asection *s;
+  flagword flags;
+
+  if (!validate_build_id_style (emit_build_id))
+    {
+      einfo ("%P: warning: unrecognized --build-id style ignored.\n");
+      return FALSE;
+    }
+
+  flags = (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_IN_MEMORY
+	   | SEC_LINKER_CREATED | SEC_READONLY | SEC_DATA);
+  s = bfd_make_section_anyway_with_flags (ibfd, ".build-id", flags);
+  if (s != NULL)
+    {
+      struct pe_tdata *t = pe_data (link_info.output_bfd);
+      t->build_id.after_write_object_contents = &write_build_id;
+      t->build_id.style = emit_build_id;
+      t->build_id.sec = s;
+
+      /* Section is a fixed size:
+	 One IMAGE_DEBUG_DIRECTORY entry, of type IMAGE_DEBUG_TYPE_CODEVIEW,
+	 pointing at a CV_INFO_PDB70 record containing the build-id, with a
+	 null byte for PdbFileName.  */
+      s->size = sizeof (struct external_IMAGE_DEBUG_DIRECTORY)
+	+ sizeof (CV_INFO_PDB70) + 1;
+
+      return TRUE;
+    }
+
+  einfo ("%P: warning: Cannot create .build-id section,"
+	 " --build-id ignored.\n");
+  return FALSE;
+}
+
 static void
 gld_${EMULATION_NAME}_after_open (void)
 {
@@ -1257,6 +1438,26 @@ gld_${EMULATION_NAME}_after_open (void)
     }
 #endif
 
+  if (emit_build_id != NULL)
+    {
+      bfd *abfd;
+
+      /* Find a COFF input.  */
+      for (abfd = link_info.input_bfds;
+	   abfd != (bfd *) NULL; abfd = abfd->link_next)
+	if (bfd_get_flavour (abfd) == bfd_target_coff_flavour)
+	  break;
+
+      /* If there are no COFF input files do not try to
+	 add a build-id section.  */
+      if (abfd == NULL
+	  || !setup_build_id (abfd))
+	{
+	  free ((char *) emit_build_id);
+	  emit_build_id = NULL;
+	}
+    }
+
   /* Pass the wacky PE command line options into the output bfd.
      FIXME: This should be done via a function, rather than by
      including an internal BFD header.  */
@@ -1279,17 +1480,23 @@ gld_${EMULATION_NAME}_after_open (void)
      find it, so enable it in that case.  */
   if (pe_use_coff_long_section_names < 0 && link_info.strip == strip_none)
     {
-      /* Iterate over all sections of all input BFDs, checking
-         for any that begin 'debug_' and are long names.  */
-      LANG_FOR_EACH_INPUT_STATEMENT (is)
+      if (link_info.relocatable)
+	pe_use_coff_long_section_names = 1;
+      else
 	{
-	  int found_debug = 0;
-	  bfd_map_over_sections (is->the_bfd, debug_section_p, &found_debug);
-	  if (found_debug)
-	    {
-	      pe_use_coff_long_section_names = 1;
-	      break;
-	    }
+	  /* Iterate over all sections of all input BFDs, checking
+	     for any that begin 'debug_' and are long names.  */
+	  LANG_FOR_EACH_INPUT_STATEMENT (is)
+	  {
+	    int found_debug = 0;
+
+	    bfd_map_over_sections (is->the_bfd, debug_section_p, &found_debug);
+	    if (found_debug)
+	      {
+		pe_use_coff_long_section_names = 1;
+		break;
+	      }
+	  }
 	}
     }
 
diff --git a/ld/emultempl/pep.em b/ld/emultempl/pep.em
index dca36cc..d1575e2 100644
--- a/ld/emultempl/pep.em
+++ b/ld/emultempl/pep.em
@@ -64,6 +64,7 @@ fragment <<EOF
 #include "ldlex.h"
 #include "ldmisc.h"
 #include "ldctor.h"
+#include "ldbuildid.h"
 #include "coff/internal.h"
 
 /* FIXME: See bfd/peXXigen.c for why we include an architecture specific
@@ -71,9 +72,10 @@ fragment <<EOF
 #include "coff/x86_64.h"
 #include "coff/pe.h"
 
-/* FIXME: This is a BFD internal header file, and we should not be
+/* FIXME: These are BFD internal header files, and we should not be
    using it here.  */
 #include "../bfd/libcoff.h"
+#include "../bfd/libpei.h"
 
 #undef  AOUTSZ
 #define AOUTSZ		PEPAOUTSZ
@@ -146,6 +148,7 @@ static int support_old_code = 0;
 static lang_assignment_statement_type *image_base_statement = 0;
 static unsigned short pe_dll_characteristics = 0;
 static bfd_boolean insert_timestamp = FALSE;
+static const char *emit_build_id;
 
 #ifdef DLL_SUPPORT
 static int    pep_enable_stdcall_fixup = 1; /* 0=disable 1=enable (default).  */
@@ -242,7 +245,8 @@ enum options
   OPTION_NO_BIND,
   OPTION_WDM_DRIVER,
   OPTION_INSERT_TIMESTAMP,
-  OPTION_TERMINAL_SERVER_AWARE
+  OPTION_TERMINAL_SERVER_AWARE,
+  OPTION_BUILD_ID
 };
 
 static void
@@ -318,6 +322,7 @@ gld${EMULATION_NAME}_add_options
     {"wdmdriver", no_argument, NULL, OPTION_WDM_DRIVER},
     {"tsaware", no_argument, NULL, OPTION_TERMINAL_SERVER_AWARE},
     {"insert-timestamp", no_argument, NULL, OPTION_INSERT_TIMESTAMP},
+    {"build-id", optional_argument, NULL, OPTION_BUILD_ID},
     {NULL, no_argument, NULL, 0}
   };
 
@@ -355,7 +360,7 @@ typedef struct
 #define U_SIZE(CSTR) \
   (sizeof (CSTR) + (is_underscoring () == 0 ? 0 : 1))
 
-#define D(field,symbol,def,usc)  {&pep.field,sizeof(pep.field), def, symbol,0, usc}
+#define D(field,symbol,def,usc)  {&pep.field, sizeof (pep.field), def, symbol, 0, usc}
 
 static definfo init[] =
 {
@@ -453,6 +458,7 @@ gld_${EMULATION_NAME}_list_options (FILE *file)
   fprintf (file, _("  --no-bind			 Do not bind this image\n"));
   fprintf (file, _("  --wdmdriver		 Driver uses the WDM model\n"));
   fprintf (file, _("  --tsaware                  Image is Terminal Server aware\n"));
+  fprintf (file, _("  --build-id[=STYLE]         Generate build ID\n"));
 #endif
 }
 
@@ -643,6 +649,7 @@ set_pep_stack_heap (char *resname, char *comname)
     einfo (_("%P%F: strange hex info for PE parameter '%s'\n"), optarg);
 }
 
+#define DEFAULT_BUILD_ID_STYLE	"md5"
 
 static bfd_boolean
 gld${EMULATION_NAME}_handle_option (int optc)
@@ -816,6 +823,17 @@ gld${EMULATION_NAME}_handle_option (int optc)
     case OPTION_TERMINAL_SERVER_AWARE:
       pe_dll_characteristics |= IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE;
       break;
+    case OPTION_BUILD_ID:
+      if (emit_build_id != NULL)
+	{
+	  free ((char *) emit_build_id);
+	  emit_build_id = NULL;
+	}
+      if (optarg == NULL)
+	optarg = DEFAULT_BUILD_ID_STYLE;
+      if (strcmp (optarg, "none"))
+	emit_build_id = xstrdup (optarg);
+      break;
     }
 
   /*  Set DLLCharacteristics bits  */
@@ -1187,10 +1205,174 @@ static void
 debug_section_p (bfd *abfd ATTRIBUTE_UNUSED, asection *sect, void *obj)
 {
   int *found = (int *) obj;
+
   if (strncmp (".debug_", sect->name, sizeof (".debug_") - 1) == 0)
     *found = 1;
 }
 
+static bfd_boolean
+pecoff_checksum_contents (bfd *abfd,
+			  void (*process) (const void *, size_t, void *),
+			  void *arg)
+{
+  file_ptr filepos = (file_ptr) 0;
+
+  while (1)
+    {
+      unsigned char b;
+      int status;
+
+      if (bfd_seek (abfd, filepos, SEEK_SET) != 0)
+	return 0;
+
+      status = bfd_bread (&b, (bfd_size_type) 1, abfd);
+      if (status < 1)
+        {
+          break;
+        }
+
+      (*process) (&b, 1, arg);
+      filepos += 1;
+    }
+
+  return TRUE;
+}
+
+static bfd_boolean
+write_build_id (bfd *abfd)
+{
+  struct pe_tdata *t = pe_data (abfd);
+  asection *asec;
+  struct bfd_link_order *link_order = NULL;
+  unsigned char *contents;
+  bfd_size_type size;
+  bfd_size_type build_id_size;
+  unsigned char *build_id;
+
+  /* Find the section the .build-id output section has been merged info.  */
+  for (asec = abfd->sections; asec != NULL; asec = asec->next)
+    {
+      struct bfd_link_order *l = NULL;
+      for (l = asec->map_head.link_order; l != NULL; l = l->next)
+        {
+          if ((l->type == bfd_indirect_link_order))
+            {
+              if (l->u.indirect.section == t->build_id.sec)
+                {
+                  link_order = l;
+                  break;
+                }
+            }
+        }
+
+      if (link_order)
+        break;
+    }
+
+  if (!link_order)
+    {
+      einfo (_("%P: warning: .build-id section discarded,"
+               " --build-id ignored.\n"));
+      return TRUE;
+    }
+
+  if (t->build_id.sec->contents == NULL)
+    t->build_id.sec->contents = (unsigned char *) xmalloc (t->build_id.sec->size);
+  contents = t->build_id.sec->contents;
+  size = t->build_id.sec->size;
+
+  build_id_size = compute_build_id_size (t->build_id.style);
+  build_id = xmalloc (build_id_size);
+  generate_build_id (abfd, t->build_id.style, pecoff_checksum_contents, build_id, build_id_size);
+
+  bfd_vma ib = pe_data (link_info.output_bfd)->pe_opthdr.ImageBase;
+
+  /* Construct a debug directory entry which points to an immediately following CodeView record.  */
+  struct internal_IMAGE_DEBUG_DIRECTORY idd;
+  idd.Characteristics = 0;
+  idd.TimeDateStamp = 0;
+  idd.MajorVersion = 0;
+  idd.MinorVersion = 0;
+  idd.Type = PE_IMAGE_DEBUG_TYPE_CODEVIEW;
+  idd.SizeOfData = sizeof (CV_INFO_PDB70) + 1;
+  idd.AddressOfRawData = asec->vma - ib + link_order->offset
+    + sizeof (struct external_IMAGE_DEBUG_DIRECTORY);
+  idd.PointerToRawData = asec->filepos + link_order->offset
+    + sizeof (struct external_IMAGE_DEBUG_DIRECTORY);
+
+  struct external_IMAGE_DEBUG_DIRECTORY *ext = (struct external_IMAGE_DEBUG_DIRECTORY *)contents;
+  _bfd_XXi_swap_debugdir_out (abfd, &idd, ext);
+
+  /* Write the debug directory enttry */
+  if (bfd_seek (abfd, asec->filepos + link_order->offset, SEEK_SET) != 0)
+    return 0;
+
+  if ((bfd_bwrite (contents, size, abfd) != size))
+    return 0;
+
+  /* Construct the CodeView record.  */
+  CODEVIEW_INFO cvinfo;
+  cvinfo.CVSignature = CVINFO_PDB70_CVSIGNATURE;
+  cvinfo.Age = 1;
+
+  /* Zero pad or truncate the generated build_id to fit in the CodeView record.  */
+  memset (&(cvinfo.Signature), 0, CV_INFO_SIGNATURE_LENGTH);
+  memcpy (&(cvinfo.Signature), build_id, (build_id_size > CV_INFO_SIGNATURE_LENGTH)
+	  ? CV_INFO_SIGNATURE_LENGTH :  build_id_size);
+
+  free (build_id);
+
+  /* Write the codeview record.  */
+  if (_bfd_XXi_write_codeview_record (abfd, idd.PointerToRawData, &cvinfo) == 0)
+    return 0;
+
+  /* Record the location of the debug directory in the data directory.  */
+  pe_data (link_info.output_bfd)->pe_opthdr.DataDirectory[PE_DEBUG_DATA].VirtualAddress
+    = asec->vma  - ib + link_order->offset;
+  pe_data (link_info.output_bfd)->pe_opthdr.DataDirectory[PE_DEBUG_DATA].Size
+    = sizeof (struct external_IMAGE_DEBUG_DIRECTORY);
+
+  return TRUE;
+}
+
+/* Make .build-id section, and set up coff_tdata->build_id. */
+static bfd_boolean
+setup_build_id (bfd *ibfd)
+{
+  asection *s;
+  flagword flags;
+
+  if (!validate_build_id_style (emit_build_id))
+    {
+      einfo ("%P: warning: unrecognized --build-id style ignored.\n");
+      return FALSE;
+    }
+
+  flags = (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_IN_MEMORY
+	   | SEC_LINKER_CREATED | SEC_READONLY | SEC_DATA);
+  s = bfd_make_section_anyway_with_flags (ibfd, ".build-id", flags);
+  if (s != NULL)
+    {
+      struct pe_tdata *t = pe_data (link_info.output_bfd);
+      t->build_id.after_write_object_contents = &write_build_id;
+      t->build_id.style = emit_build_id;
+      t->build_id.sec = s;
+
+      /* Section is a fixed size:
+	 One IMAGE_DEBUG_DIRECTORY entry, of type IMAGE_DEBUG_TYPE_CODEVIEW,
+	 pointing at a CV_INFO_PDB70 record containing the build-id, with a
+	 null byte for PdbFileName.  */
+      s->size = sizeof (struct external_IMAGE_DEBUG_DIRECTORY)
+	+ sizeof (CV_INFO_PDB70) + 1;
+
+      return TRUE;
+    }
+
+  einfo ("%P: warning: Cannot create .build-id section,"
+	 " --build-id ignored.\n");
+  return FALSE;
+}
+
 static void
 gld_${EMULATION_NAME}_after_open (void)
 {
@@ -1214,6 +1396,26 @@ gld_${EMULATION_NAME}_after_open (void)
     }
 #endif
 
+  if (emit_build_id != NULL)
+    {
+      bfd *abfd;
+
+      /* Find a COFF input.  */
+      for (abfd = link_info.input_bfds;
+	   abfd != (bfd *) NULL; abfd = abfd->link_next)
+	if (bfd_get_flavour (abfd) == bfd_target_coff_flavour)
+	  break;
+
+      /* If there are no COFF input files do not try to
+	 add a build-id section.  */
+      if (abfd == NULL
+	  || !setup_build_id (abfd))
+	{
+	  free ((char *) emit_build_id);
+	  emit_build_id = NULL;
+	}
+    }
+
   /* Pass the wacky PE command line options into the output bfd.
      FIXME: This should be done via a function, rather than by
      including an internal BFD header.  */
@@ -1236,17 +1438,23 @@ gld_${EMULATION_NAME}_after_open (void)
      find it, so enable it in that case.  */
   if (pep_use_coff_long_section_names < 0 && link_info.strip == strip_none)
     {
-      /* Iterate over all sections of all input BFDs, checking
-         for any that begin 'debug_' and are long names.  */
-      LANG_FOR_EACH_INPUT_STATEMENT (is)
+      if (link_info.relocatable)
+	pep_use_coff_long_section_names = 1;
+      else
 	{
-	  int found_debug = 0;
-	  bfd_map_over_sections (is->the_bfd, debug_section_p, &found_debug);
-	  if (found_debug)
-	    {
-	      pep_use_coff_long_section_names = 1;
-	      break;
-	    }
+	  /* Iterate over all sections of all input BFDs, checking
+	     for any that begin 'debug_' and are long names.  */
+	  LANG_FOR_EACH_INPUT_STATEMENT (is)
+	  {
+	    int found_debug = 0;
+
+	    bfd_map_over_sections (is->the_bfd, debug_section_p, &found_debug);
+	    if (found_debug)
+	      {
+		pep_use_coff_long_section_names = 1;
+		break;
+	      }
+	  }
 	}
     }