Re: Discussion about merging Go frontend

[Dave Korn <dave dot korn dot cygwin at gmail dot com>]

On 29/10/2010 02:31, Ian Lance Taylor wrote:

> This implements an object file reader/writer which does everything
> required by LTO and gccgo.  The ELF code works.  I have not tested the
> Mach-O and COFF code at all beyond compiling it; I hope that somebody
> else can test those targets and fix them.
> 
> With this patch, libelf is no longer needed.

  Almost, but not quite!  The attached patch switches the lto-plugin over to
use the new objfile reader as well.

lto-plugin/ChangeLog:

	* configure.ac: Don't use libelf, don't source config.gcc.
	(LIBELFLIBS): Delete.
	(LIBELFINC): Delete.
	(LTO_FORMAT): Delete.
	(SYM_STYLE): New AC_SUBST var set based on $target.
	* Makefile.am (LIBELFLIBS): Delete.
	(LIBELFINC): Delete.
	(LTO_FORMAT): Delete.
	(SYM_STYLE): Import.
	(AM_CPPFLAGS): Use it.  Don't use LIBELFINC.
	(liblto_plugin_la_SOURCES): Don't use LTO_FORMAT, don't include
	any object-format-specific source file in the link.
	(liblto_plugin_la_LIBADD): Don't use LIBELFLIBS.
	* configure: Regenerate.
	* Makefile.in: Regenerate.
	* lto-plugin-elf.c: Delete.
	* lto-plugin-coff.c: Delete.
	* lto-plugin.h: Delete.
	* lto-plugin.c (O_BINARY): Definition moved here from lto-plugin.h.
	(LTO_SEGMENT_NAME): New definition.
	(LTO_SECTION_PREFIX): Definition moved here from lto-plugin.h.
	(LTO_SECTION_PREFIX_LEN): New definition.
	(struct sym_aux): Struct definition moved here from lto-plugin.h.
	(struct plugin_symtab): Likewise.
	(struct plugin_objfile): Likewise.
	(struct plugin_objfile): New struct def.
	(enum symbol_style): New enum type.
	(add_symbols): Make static.
	(claimed_files): Likewise.
	(num_claimed_files): Likewise.
	(sym_style): New global.
	(check): Make static.
	(parse_table_entry): Likewise.  Respect sym_style when extracting
	symbol from symtab entry.
	(translate): Make static.
	(resolve_conflicts): Likewise.
	(process_symtab): New function, per-section callback version of
	old object-format-specific handling from deleted lto-plugin-elf.c.
	(claim_file_handler): Convert ELF-specific version from deleted
	lto-plugin-elf.c to objfile interface and move here.
	(process_options): Allow new '-sym-style=' option.
	(onload): Don't call deleted onload_format_checks hook.

  Bootstrapped and tested all languages except java and ada on
x86_64-unknown-linux-gnu, no regressions.  There are still a couple of bugs to
iron out of the COFF-specific part of the objfile reader which I'll have fixed
later today.

  OK for trunk (once the objfile changes have gone in)?

    cheers,
      DaveK

Index: lto-plugin/lto-plugin-elf.c
===================================================================
--- lto-plugin/lto-plugin-elf.c	(revision 166059)
+++ lto-plugin/lto-plugin-elf.c	(working copy)
@@ -1,157 +0,0 @@
-/* LTO plugin for gold.
-   Copyright (C) 2009, 2010 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, 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; see the file COPYING3.  If not see
-<http://www.gnu.org/licenses/>.  */
-
-#include <assert.h>
-#include <string.h>
-#include <stdio.h>
-#include <libiberty.h>
-#include <stdlib.h>
-#include <inttypes.h>
-
-/* The presence of gelf.h is checked by the toplevel configure script.  */
-#include <gelf.h>
-
-/* Common definitions that the object format dependent code needs.  */
-#include "lto-plugin.h"
-
-/* Process all lto symtabs of file ELF. */
-
-static int
-process_symtab (Elf *elf, struct plugin_symtab *out)
-{
-  int found = 0;
-  Elf_Scn *section = 0;
-  GElf_Ehdr header;
-  GElf_Ehdr *t = gelf_getehdr (elf, &header);
-  if (t == NULL)
-    return 0;
-  assert (t == &header);
-
-  while ((section = elf_nextscn(elf, section)) != 0)
-    {
-      GElf_Shdr shdr;
-      GElf_Shdr *tshdr = gelf_getshdr (section, &shdr);
-      Elf_Data *symtab;
-      const char *t;
-      assert (tshdr == &shdr);
-      t = elf_strptr (elf, header.e_shstrndx, shdr.sh_name);
-      assert (t != NULL);
-      if (strncmp (t, LTO_SECTION_PREFIX, strlen (LTO_SECTION_PREFIX)) == 0)
-	{
-	  char *s = strrchr (t, '.');
-	  if (s)
-	      sscanf (s, ".%x", &out->id);
-	  symtab = elf_getdata (section, NULL);
-	  translate (symtab->d_buf, symtab->d_buf + symtab->d_size, out);
-	  found++;
-	}
-    }
-  return found;
-}
-
-/* Callback used by gold to check if the plugin will claim FILE. Writes
-   the result in CLAIMED. */
-
-enum ld_plugin_status
-claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
-{
-  enum ld_plugin_status status;
-  Elf *elf;
-  struct plugin_file_info lto_file;
-  int n;
-
-  memset (&lto_file, 0, sizeof (struct plugin_file_info));
-
-  if (file->offset != 0)
-    {
-      char *objname;
-      Elf *archive;
-      off_t offset;
-      /* We pass the offset of the actual file, not the archive header. */
-      int t = asprintf (&objname, "%s@0x%" PRIx64, file->name,
-                        (int64_t) file->offset);
-      check (t >= 0, LDPL_FATAL, "asprintf failed");
-      lto_file.name = objname;
-
-      archive = elf_begin (file->fd, ELF_C_READ, NULL);
-      check (elf_kind (archive) == ELF_K_AR, LDPL_FATAL,
-             "Not an archive and offset not 0");
-
-      /* elf_rand expects the offset to point to the ar header, not the
-         object itself. Subtract the size of the ar header (60 bytes).
-         We don't uses sizeof (struct ar_hd) to avoid including ar.h */
-
-      offset = file->offset - 60;
-      check (offset == elf_rand (archive, offset), LDPL_FATAL,
-             "could not seek in archive");
-      elf = elf_begin (file->fd, ELF_C_READ, archive);
-      check (elf != NULL, LDPL_FATAL, "could not find archive member");
-      elf_end (archive);
-    }
-  else
-    {
-      lto_file.name = xstrdup (file->name);
-      elf = elf_begin (file->fd, ELF_C_READ, NULL);
-    }
-  lto_file.handle = file->handle;
-
-  *claimed = 0;
-
-  if (!elf)
-    goto err;
-
-  n = process_symtab (elf, &lto_file.symtab);
-  if (n == 0)
-    goto err;
-
-  if (n > 1)
-    resolve_conflicts (&lto_file.symtab, &lto_file.conflicts);
-
-  status = add_symbols (file->handle, lto_file.symtab.nsyms,
-			lto_file.symtab.syms);
-  check (status == LDPS_OK, LDPL_FATAL, "could not add symbols");
-
-  *claimed = 1;
-  num_claimed_files++;
-  claimed_files =
-    xrealloc (claimed_files,
-	      num_claimed_files * sizeof (struct plugin_file_info));
-  claimed_files[num_claimed_files - 1] = lto_file;
-
-  goto cleanup;
-
- err:
-  free (lto_file.name);
-
- cleanup:
-  if (elf)
-    elf_end (elf);
-
-  return LDPS_OK;
-}
-
-/* Method called first thing at onload time to perform sanity checks.  */
-
-enum ld_plugin_status
-onload_format_checks (struct ld_plugin_tv *tv)
-{
-  unsigned version = elf_version (EV_CURRENT);
-  check (version != EV_NONE, LDPL_FATAL, "invalid ELF version");
-  return LDPS_OK;
-}
-
Index: lto-plugin/lto-plugin.h
===================================================================
--- lto-plugin/lto-plugin.h	(revision 166059)
+++ lto-plugin/lto-plugin.h	(working copy)
@@ -1,84 +0,0 @@
-/* Common declarations for LTO plugin for gold and/or GNU ld.
-   Copyright (C) 2009, 2010 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, 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; see the file COPYING3.  If not see
-<http://www.gnu.org/licenses/>.  */
-
-#include <stdbool.h>
-#include "plugin-api.h"
-
-/* LTO magic section name.  */
-
-#define LTO_SECTION_PREFIX ".gnu.lto_.symtab"
-
-/* The part of the symbol table the plugin has to keep track of. Note that we
-   must keep SYMS until all_symbols_read is called to give the linker time to
-   copy the symbol information. */
-
-struct sym_aux
-{
-  uint32_t slot;
-  unsigned id;
-  unsigned next_conflict;
-};
-
-struct plugin_symtab
-{
-  int nsyms;
-  struct sym_aux *aux;
-  struct ld_plugin_symbol *syms;
-  unsigned id;
-};
-
-/* All that we have to remember about a file. */
-
-struct plugin_file_info
-{
-  char *name;
-  void *handle;
-  struct plugin_symtab symtab;
-  struct plugin_symtab conflicts;
-};
-
-/* These are the methods supplied by one of the object format
-   dependent files lto-plugin-elf.c or lto-plugin-coff.c  */
-
-extern enum ld_plugin_status claim_file_handler
-		(const struct ld_plugin_input_file *file, int *claimed);
-
-extern enum ld_plugin_status onload_format_checks (struct ld_plugin_tv *tv);
-
-/* These methods are made available to the object format
-   dependent files.  */
-
-extern void check (bool gate, enum ld_plugin_level level, const char *text);
-
-extern void translate (char *data, char *end, struct plugin_symtab *out);
-
-extern char *parse_table_entry (char *p, struct ld_plugin_symbol *entry,
-			struct sym_aux *aux);
-
-extern void resolve_conflicts (struct plugin_symtab *t,
-			struct plugin_symtab *conflicts);
-
-/* And this callback function is exposed.  */
-
-extern ld_plugin_add_symbols add_symbols;
-
-/* Along with these two variables.  */
-
-extern struct plugin_file_info *claimed_files;
-extern unsigned int num_claimed_files;
-
Index: lto-plugin/configure.ac
===================================================================
--- lto-plugin/configure.ac	(revision 166059)
+++ lto-plugin/configure.ac	(working copy)
@@ -6,18 +6,21 @@
 AM_MAINTAINER_MODE
 AC_PROG_CC
 AC_SYS_LARGEFILE
-AC_ARG_VAR(LIBELFLIBS,[How to link libelf])
-AC_ARG_VAR(LIBELFINC,[How to find libelf include files])
 AM_PROG_LIBTOOL
 AC_SUBST(target_noncanonical)
-. ${srcdir}/../gcc/config.gcc
-case ${lto_binary_reader} in
-  *coff*) LTO_FORMAT=coff ;;
-  *elf*)  LTO_FORMAT=elf ;;
-  *) AC_MSG_ERROR([LTO plugin is not supported on this target.]) ;;
+# Trying to get this information from gcc's config is tricky.
+case $target in
+  x86_64*-mingw*)
+    SYM_STYLE=-DSYM_STYLE=ss_none
+    ;;
+  *-cygwin* | i?86*-mingw* )
+    SYM_STYLE=-DSYM_STYLE=ss_win32
+    ;;
+  *)
+    SYM_STYLE=-DSYM_STYLE=ss_none
+    ;;
 esac
-
-AC_SUBST(LTO_FORMAT)
+AC_SUBST(SYM_STYLE)
 AC_TYPE_UINT64_T
 AC_CONFIG_FILES(Makefile)
 AC_OUTPUT
Index: lto-plugin/lto-plugin-coff.c
===================================================================
--- lto-plugin/lto-plugin-coff.c	(revision 166059)
+++ lto-plugin/lto-plugin-coff.c	(working copy)
@@ -1,38 +0,0 @@
-/* LTO plugin for gold.
-   Copyright (C) 2010 Free Software Foundation, Inc.
-
-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, 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; see the file COPYING3.  If not see
-<http://www.gnu.org/licenses/>.  */
-
-/* Common definitions that the object format dependent code needs.  */
-#include "lto-plugin.h"
-
-/* Callback used by gold to check if the plugin will claim FILE. Writes
-   the result in CLAIMED. */
-
-enum ld_plugin_status
-claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
-{
-  /* To be implemented; for now, simply do nothing.  */
-  return LDPS_OK;
-}
-
-/* Method called first thing at onload time to perform sanity checks.  */
-
-enum ld_plugin_status
-onload_format_checks (struct ld_plugin_tv *tv)
-{
-  return LDPS_OK;
-}
-
Index: lto-plugin/Makefile.am
===================================================================
--- lto-plugin/Makefile.am	(revision 166059)
+++ lto-plugin/Makefile.am	(working copy)
@@ -7,20 +7,16 @@
 target_noncanonical := @target_noncanonical@
 libexecsubdir := $(libexecdir)/gcc/$(target_noncanonical)/$(gcc_version)

-# How to find libelf
-LIBELFLIBS = @LIBELFLIBS@
-LIBELFINC = @LIBELFINC@
+# Which symbol format to use.
+SYM_STYLE = @SYM_STYLE@

-# Which object format to parse.
-LTO_FORMAT = @LTO_FORMAT@
-
-AM_CPPFLAGS = -I$(top_srcdir)/../include $(LIBELFINC)
+AM_CPPFLAGS = -I$(top_srcdir)/../include $(SYM_STYLE)
 AM_CFLAGS = -Wall -Werror

 libexecsub_LTLIBRARIES = liblto_plugin.la

-liblto_plugin_la_SOURCES = lto-plugin.c lto-plugin-$(LTO_FORMAT).c
-liblto_plugin_la_LIBADD = $(LIBELFLIBS) \
+liblto_plugin_la_SOURCES = lto-plugin.c
+liblto_plugin_la_LIBADD = \
 	$(if $(wildcard ../libiberty/pic/libiberty.a),../libiberty/pic/libiberty.a,)
 liblto_plugin_la_LDFLAGS = -no-undefined -bindir $(libexecsubdir) \
 	$(if $(wildcard ../libiberty/pic/libiberty.a),,-Wc,../libiberty/libiberty.a)
Index: lto-plugin/lto-plugin.c
===================================================================
--- lto-plugin/lto-plugin.c	(revision 166059)
+++ lto-plugin/lto-plugin.c	(working copy)
@@ -46,10 +46,73 @@
 #include <libiberty.h>
 #include <hashtab.h>
 #include "../gcc/lto/common.h"
+#include "objfile.h"
+#include "plugin-api.h"

-/* Common definitions for/from the object format dependent code.  */
-#include "lto-plugin.h"
+/* Handle opening elf files on hosts, such as Windows, that may use
+   text file handling that will break binary access.  */
+#ifndef O_BINARY
+# define O_BINARY 0
+#endif

+/* Segment name for LTO sections.  This is only used for Mach-O.
+   FIXME: This needs to be kept in sync with darwin.c.  */
+
+#define LTO_SEGMENT_NAME "__GNU_LTO"
+
+/* LTO magic section name.  */
+
+#define LTO_SECTION_PREFIX	".gnu.lto_.symtab"
+#define LTO_SECTION_PREFIX_LEN	(sizeof (LTO_SECTION_PREFIX) - 1)
+
+/* The part of the symbol table the plugin has to keep track of. Note that we
+   must keep SYMS until all_symbols_read is called to give the linker time to
+   copy the symbol information. */
+
+struct sym_aux
+{
+  uint32_t slot;
+  unsigned id;
+  unsigned next_conflict;
+};
+
+struct plugin_symtab
+{
+  int nsyms;
+  struct sym_aux *aux;
+  struct ld_plugin_symbol *syms;
+  unsigned id;
+};
+
+/* Encapsulates object file data during symbol scan.  */
+struct plugin_objfile
+{
+  int found;
+  objfile_read *objfile;
+  struct plugin_symtab *out;
+  const struct ld_plugin_input_file *file;
+};
+
+/* All that we have to remember about a file. */
+
+struct plugin_file_info
+{
+  char *name;
+  void *handle;
+  struct plugin_symtab symtab;
+  struct plugin_symtab conflicts;
+};
+
+/* Until ASM_OUTPUT_LABELREF can be hookized and decoupled from
+   stdio file streams, we do simple label translation here.  */
+
+enum symbol_style
+{
+  ss_none,	/* No underscore prefix. */
+  ss_win32,	/* Underscore prefix any symbol not beginning with '@'.  */
+  ss_uscore,	/* Underscore prefix all symbols.  */
+};
+
 static char *arguments_file_name;
 static ld_plugin_register_claim_file register_claim_file;
 static ld_plugin_register_all_symbols_read register_all_symbols_read;
@@ -58,14 +121,11 @@
 static ld_plugin_add_input_file add_input_file;
 static ld_plugin_add_input_library add_input_library;
 static ld_plugin_message message;
+static ld_plugin_add_symbols add_symbols;

-/* These are not static because the object format dependent
-   claim_file hooks in lto-plugin-{coff,elf}.c need them.  */
-ld_plugin_add_symbols add_symbols;
+static struct plugin_file_info *claimed_files = NULL;
+static unsigned int num_claimed_files = 0;

-struct plugin_file_info *claimed_files = NULL;
-unsigned int num_claimed_files = 0;
-
 static char **output_files = NULL;
 static unsigned int num_output_files = 0;

@@ -79,7 +139,12 @@
 static bool nop;
 static char *resolution_file = NULL;

-void
+/* Set by default from configure.ac, but can be overridden at runtime
+   by using -plugin-opt=-sym-style={none,win32,underscore|uscore}
+   (in fact, only first letter of style arg is checked.)  */
+static enum symbol_style sym_style = SYM_STYLE;
+
+static void
 check (bool gate, enum ld_plugin_level level, const char *text)
 {
   if (gate)
@@ -100,7 +165,7 @@
    by P and the result is written in ENTRY. The slot number is stored in SLOT.
    Returns the address of the next entry. */

-char *
+static char *
 parse_table_entry (char *p, struct ld_plugin_symbol *entry,
 		   struct sym_aux *aux)
 {
@@ -122,7 +187,24 @@
       LDPV_HIDDEN
     };

-  entry->name = xstrdup (p);
+  switch (sym_style)
+    {
+    case ss_win32:
+      if (p[0] == '@')
+	{
+    /* cf. Duff's device.  */
+    case ss_none:
+	  entry->name = xstrdup (p);
+	  break;
+	}
+    /* FALL-THROUGH.  */
+    case ss_uscore:
+      entry->name = concat ("_", p, NULL);
+      break;
+    default:
+      check (false, LDPL_FATAL, "invalid symbol style requested");
+      break;
+    }
   while (*p)
     p++;
   p++;
@@ -165,7 +247,7 @@
 /* Translate the IL symbol table located between DATA and END. Append the
    slots and symbols to OUT. */

-void
+static void
 translate (char *data, char *end, struct plugin_symtab *out)
 {
   struct sym_aux *aux;
@@ -621,7 +703,7 @@

    XXX how to handle common? */

-void
+static void
 resolve_conflicts (struct plugin_symtab *t, struct plugin_symtab *conflicts)
 {
   htab_t symtab = htab_create (t->nsyms, hash_sym, eq_sym, NULL);
@@ -689,6 +771,120 @@
   htab_delete (symtab);
 }

+/* Process one section of an object file.  */
+
+static int
+process_symtab (void *data, const char *name, off_t offset, off_t length)
+{
+  struct plugin_objfile *obj = (struct plugin_objfile *)data;
+  char *s;
+  char *secdata;
+
+  if (strncmp (name, LTO_SECTION_PREFIX, LTO_SECTION_PREFIX_LEN) != 0)
+    return 1;
+
+  s = strrchr (name, '.');
+  if (s)
+    sscanf (s, ".%x", &obj->out->id);
+  secdata = xmalloc (length);
+  offset += obj->file->offset;
+  if (offset != lseek (obj->file->fd, offset, SEEK_SET)
+	|| length != read (obj->file->fd, secdata, length))
+    {
+      if (message)
+	message (LDPL_FATAL, "%s: corrupt object file", obj->file->name);
+      /* Force claim_file_handler to abandon this file.  */
+      obj->found = 0;
+      free (data);
+      return 0;
+    }
+
+  translate (secdata, secdata + length, obj->out);
+  obj->found++;
+  free (data);
+  return 1;
+}
+
+/* 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;
+  struct plugin_objfile obj;
+  struct plugin_file_info lto_file;
+  int err;
+  const char *errmsg;
+
+  memset (&lto_file, 0, sizeof (struct plugin_file_info));
+
+  if (file->offset != 0)
+    {
+      char *objname;
+      /* We pass the offset of the actual file, not the archive header. */
+      int t = asprintf (&objname, "%s@0x%" PRIx64, file->name,
+                        (int64_t) file->offset);
+      check (t >= 0, LDPL_FATAL, "asprintf failed");
+      lto_file.name = objname;
+    }
+  else
+    {
+      lto_file.name = xstrdup (file->name);
+    }
+  lto_file.handle = file->handle;
+
+  *claimed = 0;
+  obj.file = file;
+  obj.found = 0;
+  obj.out = &lto_file.symtab;
+  errmsg = NULL;
+  obj.objfile = objfile_open_read (file->fd, file->offset, LTO_SEGMENT_NAME,
+			&errmsg, &err);
+  if (obj.objfile)
+    errmsg = objfile_find_sections (obj.objfile, process_symtab, &obj, &err);
+
+  if (!obj.objfile || errmsg)
+    {
+      if (err && message)
+	message (LDPL_FATAL, "%s: %s: %s", file->name, errmsg,
+		xstrerror (err));
+      else if (message)
+	message (LDPL_FATAL, "%s: %s", file->name, errmsg);
+      goto err;
+    }
+
+  if (obj.found == 0)
+    goto err;
+
+  if (obj.found > 1)
+    resolve_conflicts (&lto_file.symtab, &lto_file.conflicts);
+
+  status = add_symbols (file->handle, lto_file.symtab.nsyms,
+			lto_file.symtab.syms);
+  check (status == LDPS_OK, LDPL_FATAL, "could not add symbols");
+
+  *claimed = 1;
+  num_claimed_files++;
+  claimed_files =
+    xrealloc (claimed_files,
+	      num_claimed_files * sizeof (struct plugin_file_info));
+  claimed_files[num_claimed_files - 1] = lto_file;
+
+  goto cleanup;
+
+ err:
+  free (lto_file.name);
+
+ cleanup:
+  if (obj.objfile)
+    objfile_release_read (obj.objfile);
+  if (file->fd >= 0)
+    close (file->fd);
+
+  return LDPS_OK;
+}
+
 /* Parse the plugin options. */

 static void
@@ -706,6 +902,21 @@
       pass_through_items[num_pass_through_items - 1] =
           xstrdup (option + strlen ("-pass-through="));
     }
+  else if (!strncmp (option, "-sym-style=", sizeof ("-sym-style=") - 1))
+    {
+      switch (option[sizeof ("-sym-style=")])
+	{
+	case 'w':
+	  sym_style = ss_win32;
+	  break;
+	case 'u':
+	  sym_style = ss_uscore;
+	  break;
+	default:
+	  sym_style = ss_none;
+	  break;
+	}
+    }
   else
     {
       int size;
@@ -727,10 +938,6 @@
   struct ld_plugin_tv *p;
   enum ld_plugin_status status;

-  status = onload_format_checks (tv);
-  if (status != LDPS_OK)
-    return status;
-
   p = tv;
   while (p->tv_tag)
     {