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 (espind...@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 (<o_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, "%...@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, <o_file.symtab);
- if (n == 0)
- goto err;
-
- if (n > 1)
- resolve_conflicts (<o_file.symtab, <o_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 (espind...@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 (<o_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, "%...@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 = <o_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 (<o_file.symtab, <o_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)
{
