Re: [lto][patch] Add initial gold plugin

["Rafael Espindola" <espindola at google dot com>]

> An updated version is attached. Could you please take another look?

Now it is ...

Cheers,
-- 
Rafael Avila de Espindola

Google | Gordon House | Barrow Street | Dublin 4 | Ireland
Registered in Dublin, Ireland | Registration Number: 368047

diff --git a/lto-plugin/Makefile.am b/lto-plugin/Makefile.am
index db159bd..acc0565 100644
--- a/lto-plugin/Makefile.am
+++ b/lto-plugin/Makefile.am
@@ -1,4 +1,13 @@
 AM_CPPFLAGS = -I$(top_srcdir)/../include
+
+AM_CFLAGS = -Wall -Werror
+
 bin_PROGRAMS = ltosymtab
+
 ltosymtab_SOURCES = lto-symtab.c
-ltosymtab_LDADD = -lelf
+ltosymtab_LDADD = -ldl
+
+lib_LTLIBRARIES = liblto_plugin.la
+
+liblto_plugin_la_SOURCES = lto-plugin.c
+liblto_plugin_la_LIBADD = -lelf
diff --git a/lto-plugin/acinclude.m4 b/lto-plugin/acinclude.m4
index 9302f26..655ba7a 100644
--- a/lto-plugin/acinclude.m4
+++ b/lto-plugin/acinclude.m4
@@ -1,3 +1,6 @@
-m4_include(../config/acx.m4)
-m4_include(../config/no-executables.m4)
 m4_include([../config/libelf.m4])
+m4_include([../ltsugar.m4])
+m4_include([../ltoptions.m4])
+m4_include([../ltversion.m4])
+
+sinclude(../libtool.m4)
diff --git a/lto-plugin/configure.ac b/lto-plugin/configure.ac
index e967a22..c2c9ea5 100644
--- a/lto-plugin/configure.ac
+++ b/lto-plugin/configure.ac
@@ -4,5 +4,6 @@ GCC_TOPLEV_SUBDIRS
 AM_INIT_AUTOMAKE([foreign])
 AC_PROG_CC
 AC_CHECK_GELF
+AM_PROG_LIBTOOL
 AC_CONFIG_FILES(Makefile)
 AC_OUTPUT
diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
new file mode 100644
index 0000000..bd4b2f4
--- /dev/null
+++ b/lto-plugin/lto-plugin.c
@@ -0,0 +1,247 @@
+/* LTO plugin for gold.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   Contributed by Rafael Avila de Espindola (espindola@google.com).
+
+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.  */
+
+/* The plugin has only one external function: onload. Gold passes it an array of
+   function that the plugin uses to communicate back to gold.
+
+   With the functions provided by gold, the plugin can be notified when
+   gold first analyzes a file and pass a symbol table back to gold. The plugin
+   is also notified when all symbols have been read and it is time to generate
+   machine code for the necessary symbols.
+
+   More information at http://gcc.gnu.org/wiki/whopr/driver.
+*/
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+
+#ifdef HAVE_GELF_H
+# include <gelf.h>
+#else
+# if defined(HAVE_LIBELF_GELF_H)
+#   include <libelf/gelf.h>
+# else
+#  error "gelf.h not available"
+# endif
+#endif
+
+#include "plugin-api.h"
+
+static ld_plugin_register_claim_file register_claim_file;
+static ld_plugin_add_symbols add_symbols;
+
+/* Parse an entry of the IL symbol table. The data to be parsed is pointed
+   by P and the result is written in ENTRY. The slot number is stored in SLOT.
+   Returns the address of the next entry. */
+
+static char *
+parse_table_entry (char *p, struct ld_plugin_symbol *entry, uint32_t *slot)
+{
+  unsigned char t;
+  enum ld_plugin_symbol_kind translate_kind[] =
+    {
+      LDPK_DEF,
+      LDPK_WEAKDEF,
+      LDPK_UNDEF,
+      LDPK_WEAKUNDEF,
+      LDPK_COMMON
+    };
+
+  enum ld_plugin_symbol_visibility translate_visibility[] =
+    {
+      LDPV_DEFAULT,
+      LDPV_PROTECTED,
+      LDPV_INTERNAL,
+      LDPV_HIDDEN
+    };
+
+  entry->name = p;
+  while (*p)
+    p++;
+  p++;
+
+  entry->version = NULL;
+
+  entry->comdat_key = p;
+  while (*p)
+    p++;
+  p++;
+
+  if (strcmp (entry->comdat_key, "") == 0)
+    entry->comdat_key = NULL;
+
+  t = *p;
+  assert (t <= 4);
+  entry->def = translate_kind[t];
+  p++;
+
+  t = *p;
+  assert (t <= 3);
+  entry->visibility = translate_visibility[t];
+  p++;
+
+  entry->size = *(uint64_t *) p;
+  p += 8;
+
+  *slot = *(uint32_t *) p;
+  p += 4;
+
+  entry->resolution = LDPR_UNKNOWN;
+
+  return p;
+}
+
+/* Returns the string table of file ELF. */
+
+static const char *
+get_string_table (Elf *elf)
+{
+  GElf_Ehdr header;
+  GElf_Ehdr *t = gelf_getehdr (elf, &header);
+  assert (t == &header);
+  Elf_Scn *section = elf_getscn (elf, header.e_shstrndx);
+  assert (section);
+  Elf_Data *data = 0;
+  data = elf_getdata (section, data);
+  assert (data);
+  assert (data->d_buf);
+  return (const char *) data->d_buf;
+}
+
+
+/* Return the section in ELF that is named NAME. */
+
+static Elf_Scn *
+get_section (Elf *elf, const char *name)
+{
+  const char *string_table = get_string_table (elf);
+  Elf_Scn *section = 0;
+  while ((section = elf_nextscn(elf, section)) != 0)
+    {
+      GElf_Shdr shdr;
+      GElf_Shdr *tshdr = gelf_getshdr (section, &shdr);
+      const char *t;
+      assert (tshdr == &shdr);
+      t = string_table + shdr.sh_name;
+      if (strcmp (t, name) == 0)
+	return section;
+    }
+  return NULL;
+}
+
+/* Returns the IL symbol table of file ELF. */
+
+static Elf_Data *
+get_symtab (Elf *elf)
+{
+  Elf_Data *data = 0;
+  Elf_Scn *section = get_section (elf, ".gnu.lto_.symtab");
+  if (!section)
+    return NULL;
+
+  data = elf_getdata (section, data);
+  assert (data);
+  return data;
+}
+
+/* Translate the IL symbol tabel SYMTAB into an array of ld_plugin_symbol
+   and return it. Write the array size in SIZE. */
+
+static struct ld_plugin_symbol *
+translate (Elf_Data *symtab, int *size)
+{
+  char *data = symtab->d_buf;
+  char *end = data + symtab->d_size;
+  struct ld_plugin_symbol *ret = NULL;
+  int n = 0;
+  while (data < end)
+    {
+      uint32_t slot;
+      n++;
+      ret = realloc (ret, n * sizeof (struct ld_plugin_symbol));
+      assert (ret);
+      data = parse_table_entry (data, &ret[n - 1], &slot);
+    }
+  *size = n;
+  return ret;
+}
+
+/* Callback used by gold to check if the plugin will claim FILE. Writes
+   the result in CLAIMED. */
+
+static enum ld_plugin_status
+claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
+{
+  enum ld_plugin_status status;
+  Elf *elf = elf_begin (file->fd, ELF_C_READ, NULL);
+  int num;
+  Elf_Data *symtab;
+  struct ld_plugin_symbol *syms;
+
+  *claimed = 0;
+
+  if (!elf)
+    return LDPS_OK;
+
+  symtab = get_symtab (elf);
+  if (!symtab)
+    return LDPS_OK;
+
+  syms = translate (symtab, &num);
+
+  status = add_symbols (file->handle, num, syms);
+  assert (status == LDPS_OK);
+
+  *claimed = 1;
+  return LDPS_OK;
+}
+
+/* Called by gold after loading the plugin. TV is the transfer vector. */
+
+void
+onload (struct ld_plugin_tv *tv)
+{
+  struct ld_plugin_tv *p;
+  enum ld_plugin_status status;
+
+  unsigned version = elf_version (EV_CURRENT);
+  assert (version != EV_NONE);
+
+  p = tv;
+  while (p->tv_tag)
+    {
+      switch (p->tv_tag)
+	{
+	case LDPT_REGISTER_CLAIM_FILE_HOOK:
+	  register_claim_file = p->tv_u.tv_register_claim_file;
+	  break;
+	case LDPT_ADD_SYMBOLS:
+	  add_symbols = p->tv_u.tv_add_symbols;
+	  break;
+	default:
+	  break;
+	}
+      p++;
+    }
+
+  assert (register_claim_file);
+  assert (add_symbols);
+  status = register_claim_file (claim_file_handler);
+  assert (status == LDPS_OK);
+}
diff --git a/lto-plugin/lto-symtab.c b/lto-plugin/lto-symtab.c
index 82253f2..126c563 100644
--- a/lto-plugin/lto-symtab.c
+++ b/lto-plugin/lto-symtab.c
@@ -1,10 +1,10 @@
 /* Program to read the IL symbol table.
-   Copyright (C) 1999, 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
-   Contributed by Vladimir Makarov (vmakarov@cygnus.com).
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   Contributed by Rafael Avila de Espindola (espindola@google.com).
 
 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 of the License, or
+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,
@@ -18,146 +18,126 @@ Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
 
 #include <fcntl.h>
 #include <assert.h>
-#ifdef HAVE_GELF_H
-# include <gelf.h>
-#else
-# if defined(HAVE_LIBELF_GELF_H)
-#   include <libelf/gelf.h>
-# else
-#  error "gelf.h not available"
-# endif
-#endif
+#include <dlfcn.h>
 #include <stdio.h>
-#include <string.h>
-#include "lto-symtab.h"
+#include <inttypes.h>
 
-/* Return the string table of ELF. */
 
-const char *
-get_string_table (Elf *elf)
+
+#include "plugin-api.h"
+
+ld_plugin_claim_file_handler claim_file_handler;
+void *current_file_handle;
+
+/* Register HANDLER as the callback for claiming a file. */
+
+enum ld_plugin_status
+register_claim_file(ld_plugin_claim_file_handler handler)
 {
-  GElf_Ehdr header;
-  GElf_Ehdr *t = gelf_getehdr (elf, &header);
-  assert (t == &header);
-  Elf_Scn *section = elf_getscn (elf, header.e_shstrndx);
-  assert (section);
-  Elf_Data *data = 0;
-  data = elf_getdata (section, data);
-  assert (data);
-  assert (data->d_buf);
-  return (const char *) data->d_buf;
+  claim_file_handler = handler;
+  return LDPS_OK;
 }
 
-/* Return the section in ELF that is named NAME. */
+/* For a file identified by HANDLE, add NSYMS symbols from SYMS. */
 
-Elf_Scn *
-get_section (Elf *elf, const char *name)
+static enum ld_plugin_status
+add_symbols (const void *handle, int nsyms,
+	     const struct ld_plugin_symbol *syms)
 {
-  const char *string_table = get_string_table (elf);
-  Elf_Scn *section = 0;
-  while ((section = elf_nextscn(elf, section)) != 0)
+  const char *kind_str[] = {"DEF", "WEAKDEF", "UNDEF",
+			    "WEAKUNDEF", "COMMON"};
+  const char *visibility_str[] = {"DEFAULT", "PROTECTED",
+				  "INTERNAL", "HIDDEN"};
+  const char *resolution_str[] = {"UNKNOWN", "UNDEF",
+				  "PREVAILING_DEF",
+				  "PREVAILING_DEF_IRONLY",
+				  "PREEMPTED_REG",
+				  "PREEMPTED_IR",
+				  "RESOLVED_IR",
+				  "RESOLVED_EXEC",
+				  "RESOLVED_DYN"};
+
+  int i;
+  assert (handle == current_file_handle);
+
+  for (i = 0; i < nsyms; i++)
     {
-      GElf_Shdr shdr;
-      GElf_Shdr *tshdr = gelf_getshdr (section, &shdr);
-      const char *t;
-      assert (tshdr == &shdr);
-      t = string_table + shdr.sh_name;
-      if (strcmp (t, name) == 0)
-	return section;
+      printf("name: %s; ", syms[i].name);
+      if (syms[i].version)
+	printf("version: %s;", syms[i].version);
+      else
+	printf("not versioned; ");
+      printf("kind: %s; ", kind_str[syms[i].def]);
+      printf("visibility: %s; ", visibility_str[syms[i].visibility]);
+      printf("size: %" PRId64 "; ", syms[i].size);
+      if (syms[i].comdat_key)
+	printf("comdat_key: %s; ", syms[i].comdat_key);
+      else
+	printf("no comdat_key; ");
+      printf ("resolution: %s\n", resolution_str[syms[i].resolution]);
     }
-  return NULL;
+  return LDPS_OK;
 }
 
-/* Return the IL symbol table of ELF. */
+struct ld_plugin_tv tv[] = {
+  {LDPT_REGISTER_CLAIM_FILE_HOOK,
+   {.tv_register_claim_file = register_claim_file}
+  },
+  {LDPT_ADD_SYMBOLS,
+   {.tv_add_symbols = add_symbols}
+  },
 
-Elf_Data *
-get_symtab (Elf *elf)
-{
-  Elf_Scn *section = get_section (elf, ".gnu.lto_.symtab");
-  assert (section);
-  Elf_Data *data = 0;
-  data = elf_getdata (section, data);
-  assert (data);
-  return data;
-}
-
-struct table_entry
-{
-  char *name;
-  char *comdat;
-  enum gcc_plugin_symbol_kind kind;
-  enum gcc_plugin_symbol_visibility visibility;
-  uint64_t size;
-  uint32_t slot_num;
+  {0, {0}}
 };
 
-/* Parse an entry of the IL symbol table. The data to be parsed is pointed
-   by P and the result is written in ENTRY. Returs the address of the next
-   entry. */
+/* Load a plugin from a file named NAME. */
 
-char *parse_table_entry (char *p, struct table_entry *entry)
+static void
+load_plugin (const char *name)
 {
-  entry->name = p;
-  while (*p)
-    p++;
-  p++;
-
-  entry->comdat = p;
-  while (*p)
-    p++;
-  p++;
+  ld_plugin_onload onload;
+  void *lib = dlopen (name, RTLD_LAZY);
+
+  assert (lib != NULL);
+  onload = dlsym (lib, "onload");
+  assert (onload);
+  onload (tv);
+  assert (claim_file_handler);
+}
 
-  entry->kind = *p;
-  assert (entry->kind <= 4);
-  p++;
+/* Send file named NAME to the plugin. */
 
-  entry->visibility = *p;
-  assert (entry->visibility <= 3);
-  p++;
+static void
+register_file (const char *name)
+{
+ int claimed;
+ struct ld_plugin_input_file file;
+ int fd = open (name, O_RDONLY);
+ assert (fd >= 0);
 
-  entry->size = *(uint64_t *) p;
-  p += 8;
+ file.name = (char *) name;
+ file.fd = fd;
+ file.offset = 0; /* Used only in archives. */
+ file.filesize = 0; /* Used only in archives. */
 
-  entry->slot_num = *(uint32_t *) p;
-  p += 4;
+ /* Just to check that the plugin keeps it. */
+ file.handle = &file;
+ current_file_handle = file.handle;
 
-  return p;
+ claim_file_handler (&file, &claimed);
 }
 
-/* Print the symbol table SYMTAB to stdout. */
-
-void printTable (Elf_Data *symtab)
+int
+main(int argc, char *argv[])
 {
-  char *data = symtab->d_buf;
-  char *end = data + symtab->d_size;
-  while (data < end)
-    {
-      struct table_entry entry;
-      const char *kind_str[] = {"GCCPK_DEF", "GCCPK_WEAKDEF", "GCCPK_UNDEF",
-				"GCCPK_WEAKUNDEF", "GCCPK_COMMON"};
-      const char *visibility_str[] = {"GCCPV_DEFAULT", "GCCPV_PROTECTED",
-				      "GCCPV_INTERNAL", "GCCPV_HIDDEN"};
-      data = parse_table_entry (data, &entry);
-
-      printf("%s %s %s %s %lld %d\n", entry.name, entry.comdat,
-	     kind_str[entry.kind], visibility_str[entry.visibility],
-	     entry.size, entry.slot_num);
-    }
-}
+  const char *plugin;
+  const char *obj;
+  assert (argc == 3);
+  plugin = argv[1];
+  obj = argv[2];
+
+  load_plugin (plugin);
+  register_file (obj);
 
-int main (int argc,  char *argv[])
-{
-  unsigned version = elf_version(EV_CURRENT);
-  assert (version != EV_NONE);
-  assert (argc == 2);
-  int fd = open (argv[1], O_RDONLY);
-  assert (fd >= 0);
-  Elf *elf = elf_begin(fd, ELF_C_READ, NULL);
-  assert (elf);
-
-  Elf_Data *symtab = get_symtab (elf);
-  printTable (symtab);
-
-  elf_end(elf);
   return 0;
 }
diff --git a/lto-plugin/plugin-api.h b/lto-plugin/plugin-api.h
new file mode 100644
index 0000000..7f96bbd
--- /dev/null
+++ b/lto-plugin/plugin-api.h
@@ -0,0 +1,237 @@
+/* plugin-api.h -- External plugin API for gold.  */
+
+/* Copyright 2008 Free Software Foundation, Inc.
+   Written by Cary Coutant <ccoutant@google.com>.
+
+   This file is part of gold.
+
+   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.  */
+
+/* This file defines the interface for writing a linker plugin, which is
+   described at < http://gcc.gnu.org/wiki/whopr/driver >.  */
+
+#ifndef GOLD_PLUGIN_API_H
+#define GOLD_PLUGIN_API_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+/* Status code returned by most API routines.  */
+
+enum ld_plugin_status {
+  LDPS_OK = 0,
+  LDPS_ERR,
+  /* Additional Error codes TBD.  */
+};
+
+/* The version of the API specification.  */
+
+enum ld_plugin_api_version
+{
+  LD_PLUGIN_API_VERSION = 1,
+};
+
+/* The type of output file being generated by the linker.  */
+
+enum ld_plugin_output_file_type
+{
+  LDPO_REL,
+  LDPO_EXEC,
+  LDPO_DYN,
+};
+
+/* An input file managed by the plugin library.  */
+
+struct ld_plugin_input_file
+{
+  const char *name;
+  int fd;
+  off_t offset;
+  off_t filesize;
+  void *handle;
+};
+
+/* A symbol belonging to an input file managed by the plugin library.  */
+
+struct ld_plugin_symbol
+{
+  char *name;
+  char *version;
+  int def;
+  int visibility;
+  uint64_t size;
+  char *comdat_key;
+  int resolution;
+};
+
+/* Whether the symbol is a definition, reference, or common, weak or not.  */
+
+enum ld_plugin_symbol_kind
+{
+  LDPK_DEF,
+  LDPK_WEAKDEF,
+  LDPK_UNDEF,
+  LDPK_WEAKUNDEF,
+  LDPK_COMMON,
+};
+
+/* The visibility of the symbol.  */
+
+enum ld_plugin_symbol_visibility
+{
+  LDPV_DEFAULT,
+  LDPV_PROTECTED,
+  LDPV_INTERNAL,
+  LDPV_HIDDEN,
+};
+
+/* How a symbol is resolved.  */
+
+enum ld_plugin_symbol_resolution
+{
+  LDPR_UNKNOWN = 0,
+  LDPR_UNDEF,
+  LDPR_PREVAILING_DEF,
+  LDPR_PREVAILING_DEF_IRONLY,
+  LDPR_PREEMPTED_REG,
+  LDPR_PREEMPTED_IR,
+  LDPR_RESOLVED_IR,
+  LDPR_RESOLVED_EXEC,
+  LDPR_RESOLVED_DYN,
+};
+
+/* The plugin library's "claim file" handler.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_claim_file_handler) (
+  const struct ld_plugin_input_file *file, int *claimed);
+
+/* The plugin library's "all symbols read" handler.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_all_symbols_read_handler) ();
+
+/* The plugin library's cleanup handler.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_cleanup_handler) ();
+
+/* The linker's interface for registering the "claim file" handler.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_register_claim_file) (ld_plugin_claim_file_handler handler);
+
+/* The linker's interface for registering the "all symbols read" handler.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_register_all_symbols_read) (
+  ld_plugin_all_symbols_read_handler handler);
+
+/* The linker's interface for registering the cleanup handler.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_register_cleanup) (ld_plugin_cleanup_handler handler);
+
+/* The linker's interface for adding symbols from a claimed input file.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_add_symbols) (const void *handle, int nsyms,
+                          const struct ld_plugin_symbol *syms);
+
+/* The linker's interface for retrieving symbol resolution information.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_get_symbols) (void *handle, int nsyms,
+                          struct ld_plugin_symbol *syms);
+
+/* The linker's interface for adding a compiled input file.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_add_input_file) (char *pathname);
+
+/* The linker's interface for issuing a warning or error message.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_message) (int level, char *format, ...);
+
+enum ld_plugin_level
+{
+  LDPL_INFO,
+  LDPL_WARNING,
+  LDPL_ERROR,
+  LDPL_FATAL,
+};
+
+/* Values for the tv_tag field of the transfer vector.  */
+
+enum ld_plugin_tag
+{
+  LDPT_NULL = 0,
+  LDPT_API_VERSION,
+  LDPT_GOLD_VERSION,
+  LDPT_LINKER_OUTPUT,
+  LDPT_OPTION,
+  LDPT_REGISTER_CLAIM_FILE_HOOK,
+  LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
+  LDPT_REGISTER_CLEANUP_HOOK,
+  LDPT_ADD_SYMBOLS,
+  LDPT_GET_SYMBOLS,
+  LDPT_ADD_INPUT_FILE,
+  LDPT_MESSAGE,
+};
+
+/* The plugin transfer vector.  */
+
+struct ld_plugin_tv
+{
+  enum ld_plugin_tag tv_tag;
+  union
+  {
+    int tv_val;
+    const char *tv_string;
+    ld_plugin_register_claim_file tv_register_claim_file;
+    ld_plugin_register_all_symbols_read tv_register_all_symbols_read;
+    ld_plugin_register_cleanup tv_register_cleanup;
+    ld_plugin_add_symbols tv_add_symbols;
+    ld_plugin_get_symbols tv_get_symbols;
+    ld_plugin_add_input_file tv_add_input_file;
+    ld_plugin_message tv_message;
+  } tv_u;
+};
+
+/* The plugin library's "onload" entry point.  */
+
+typedef
+enum ld_plugin_status
+(*ld_plugin_onload) (struct ld_plugin_tv *tv);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* !defined(GOLD_PLUGIN_API_H) */