Merge lto branch into trunk.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@152434 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 689 insertions, 0 deletions

diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
new file mode 100644
index 00000000000..a0c1a54e0e2
--- /dev/null
+++ b/lto-plugin/lto-plugin.c
@@ -0,0 +1,689 @@
+/* LTO plugin for gold.
+   Copyright (C) 2009 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/>.  */
+
+/* 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.
+
+   This plugin should be passed the lto-wrapper options and will forward them.
+   It also has 2 options of its own:
+   -debug: Print the command line used to run lto-wrapper.
+   -nop: Instead of running lto-wrapper, pass the original to the plugin. This
+   only works if the input files are hybrid.  */
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include <ar.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdbool.h>
+#include <libiberty.h>
+
+/* The presence of gelf.h is checked by the toplevel configure script.  */
+#include <gelf.h>
+
+#include "plugin-api.h"
+#include "../gcc/lto/common.h"
+
+/* 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 plugin_symtab
+{
+  int nsyms;
+  uint32_t *slots;
+  struct ld_plugin_symbol *syms;
+};
+
+/* All that we have to remember about a file. */
+
+struct plugin_file_info
+{
+  char *name;
+  void *handle;
+  struct plugin_symtab symtab;
+  unsigned char temp;
+};
+
+
+static char *temp_obj_dir_name;
+static ld_plugin_register_claim_file register_claim_file;
+static ld_plugin_add_symbols add_symbols;
+static ld_plugin_register_all_symbols_read register_all_symbols_read;
+static ld_plugin_get_symbols get_symbols;
+static ld_plugin_register_cleanup register_cleanup;
+static ld_plugin_add_input_file add_input_file;
+
+static struct plugin_file_info *claimed_files = NULL;
+static unsigned int num_claimed_files = 0;
+
+static char **output_files = NULL;
+static unsigned int num_output_files = 0;
+
+static char **lto_wrapper_argv;
+static int lto_wrapper_num_args;
+
+static char **pass_through_items = NULL;
+static unsigned int num_pass_through_items;
+
+static bool debug;
+static bool nop;
+
+/* 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 = strdup (p);
+  while (*p)
+    p++;
+  p++;
+
+  entry->version = NULL;
+
+  entry->comdat_key = p;
+  while (*p)
+    p++;
+  p++;
+
+  if (strlen (entry->comdat_key) == 0)
+    entry->comdat_key = NULL;
+  else
+    entry->comdat_key = strdup (entry->comdat_key);
+
+  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;
+}
+
+/* Return the section in ELF that is named NAME. */
+
+static Elf_Scn *
+get_section (Elf *elf, const char *name)
+{
+  Elf_Scn *section = 0;
+  GElf_Ehdr header;
+  GElf_Ehdr *t = gelf_getehdr (elf, &header);
+  if (t == NULL)
+    return NULL;
+  assert (t == &header);
+
+  while ((section = elf_nextscn(elf, section)) != 0)
+    {
+      GElf_Shdr shdr;
+      GElf_Shdr *tshdr = gelf_getshdr (section, &shdr);
+      const char *t;
+      assert (tshdr == &shdr);
+      t = elf_strptr (elf, header.e_shstrndx, shdr.sh_name);
+      assert (t != NULL);
+      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 table SYMTAB. Write the slots and symbols in OUT. */
+
+static void
+translate (Elf_Data *symtab, struct plugin_symtab *out)
+{
+  uint32_t *slots = NULL;
+  char *data = symtab->d_buf;
+  char *end = data + symtab->d_size;
+  struct ld_plugin_symbol *syms = NULL;
+  int n = 0;
+
+  while (data < end)
+    {
+      n++;
+      syms = realloc (syms, n * sizeof (struct ld_plugin_symbol));
+      assert (syms);
+      slots = realloc (slots, n * sizeof (uint32_t));
+      assert (slots);
+      data = parse_table_entry (data, &syms[n - 1], &slots[n - 1]);
+    }
+
+  out->nsyms = n;
+  out->syms = syms;
+  out->slots = slots;
+}
+
+/* Free all memory that is no longer needed at the beginning of all_symbols_read. */
+
+static void
+free_1 (void)
+{
+  unsigned int i;
+  for (i = 0; i < num_claimed_files; i++)
+    {
+      struct plugin_file_info *info = &claimed_files[i];
+      struct plugin_symtab *symtab = &info->symtab;
+      unsigned int j;
+      for (j = 0; j < symtab->nsyms; j++)
+	{
+	  struct ld_plugin_symbol *s = &symtab->syms[j];
+	  free (s->name);
+	  if (s->comdat_key)
+	    free (s->comdat_key);
+	}
+      free (symtab->syms);
+      symtab->syms = NULL;
+    }
+}
+
+/* Free all remaining memory. */
+
+static void
+free_2 (void)
+{
+  unsigned int i;
+  for (i = 0; i < num_claimed_files; i++)
+    {
+      struct plugin_file_info *info = &claimed_files[i];
+      struct plugin_symtab *symtab = &info->symtab;
+      free (symtab->slots);
+      free (info->name);
+    }
+
+  for (i = 0; i < num_output_files; i++)
+    free (output_files[i]);
+  free (output_files);
+
+  free (claimed_files);
+  claimed_files = NULL;
+  num_claimed_files = 0;
+
+  free (temp_obj_dir_name);
+  temp_obj_dir_name = NULL;
+}
+
+/*  Writes the relocations to disk. */
+
+static void
+write_resolution (void)
+{
+  unsigned int i;
+  FILE *f;
+  /* FIXME: Disabled for now since we are not using the resolution file. */
+  return;
+
+
+  /* FIXME: This should be a temporary file. */
+  f = fopen ("resolution", "w");
+
+  fprintf (f, "%d\n", num_claimed_files);
+
+  for (i = 0; i < num_claimed_files; i++)
+    {
+      struct plugin_file_info *info = &claimed_files[i];
+      struct plugin_symtab *symtab = &info->symtab;
+      struct ld_plugin_symbol *syms = calloc (symtab->nsyms,
+					      sizeof (struct ld_plugin_symbol));
+      unsigned j;
+
+      assert (syms);
+      get_symbols (info->handle, symtab->nsyms, syms);
+
+      fprintf (f, "%s %d\n", info->name, info->symtab.nsyms);
+
+      for (j = 0; j < info->symtab.nsyms; j++)
+	{
+	  uint32_t slot = symtab->slots[j];
+	  unsigned int resolution = syms[j].resolution;
+	  fprintf (f, "%d %s\n", slot, lto_resolution_str[resolution]);
+	}
+      free (syms);
+    }
+  fclose (f);
+}
+
+/* Pass files generated by the lto-wrapper to the linker. FD is lto-wrapper's
+   stdout. */
+
+static void
+add_output_files (FILE *f)
+{
+  char fname[1000]; /* FIXME: Is this big enough? */
+
+  for (;;)
+    {
+      size_t len;
+      char *s = fgets (fname, sizeof (fname), f);
+      if (!s)
+	break;
+
+      len = strlen (s);
+      assert (s[len - 1] == '\n');
+      s[len - 1] = '\0';
+
+      num_output_files++;
+      output_files = realloc (output_files, num_output_files * sizeof (char *));
+      output_files[num_output_files - 1] = strdup (s);
+      add_input_file (output_files[num_output_files - 1]);
+    }
+}
+
+/* Execute the lto-wrapper. ARGV[0] is the binary. The rest of ARGV is the
+   argument list. */
+
+static void
+exec_lto_wrapper (char *argv[])
+{
+  int t;
+  int status;
+  char *at_args;
+  char *args_name;
+  FILE *args;
+  FILE *wrapper_output;
+  char *new_argv[3];
+  struct pex_obj *pex;
+  const char *errmsg;
+
+  /* Write argv to a file to avoid a command line that is too long. */
+  t = asprintf (&at_args, "@%s/arguments", temp_obj_dir_name);
+  assert (t >= 0);
+
+  args_name = at_args + 1;
+  args = fopen (args_name, "w");
+  assert (args);
+
+  t = writeargv (&argv[1], args);
+  assert (t == 0);
+  t = fclose (args);
+  assert (t == 0);
+
+  new_argv[0] = argv[0];
+  new_argv[1] = at_args;
+  new_argv[2] = NULL;
+
+  if (debug)
+    {
+      int i;
+      for (i = 0; new_argv[i]; i++)
+	fprintf (stderr, "%s ", new_argv[i]);
+      fprintf (stderr, "\n");
+    }
+
+
+  pex = pex_init (PEX_USE_PIPES, "lto-wrapper", NULL);
+  assert (pex != NULL);
+
+  errmsg = pex_run (pex, 0, new_argv[0], new_argv, NULL, NULL, &t);
+  assert (errmsg == NULL);
+  assert (t == 0);
+
+  wrapper_output = pex_read_output (pex, 0);
+  assert (wrapper_output);
+
+  add_output_files (wrapper_output);
+
+  t = pex_get_status (pex, 1, &status);
+  assert (t == 1);
+  assert (WIFEXITED (status) && WEXITSTATUS (status) == 0);
+
+  pex_free (pex);
+
+  t = unlink (args_name);
+  assert (t == 0);
+  free (at_args);
+}
+
+/* Pass the original files back to the linker. */
+
+static void
+use_original_files (void)
+{
+  unsigned i;
+  for (i = 0; i < num_claimed_files; i++)
+    {
+      struct plugin_file_info *info = &claimed_files[i];
+      add_input_file (info->name);
+    }
+}
+
+
+/* Called by the linker once all symbols have been read. */
+
+static enum ld_plugin_status
+all_symbols_read_handler (void)
+{
+  unsigned i;
+  unsigned num_lto_args = num_claimed_files + lto_wrapper_num_args + 1;
+  char **lto_argv;
+  const char **lto_arg_ptr;
+  if (num_claimed_files == 0)
+    return LDPS_OK;
+
+  free_1 ();
+
+  if (nop)
+    {
+      use_original_files ();
+      return LDPS_OK;
+    }
+
+  lto_argv = (char **) calloc (sizeof (char *), num_lto_args);
+  lto_arg_ptr = (const char **) lto_argv;
+  assert (lto_wrapper_argv);
+
+  write_resolution ();
+
+  for (i = 0; i < lto_wrapper_num_args; i++)
+    *lto_arg_ptr++ = lto_wrapper_argv[i];
+
+  for (i = 0; i < num_claimed_files; i++)
+    {
+      struct plugin_file_info *info = &claimed_files[i];
+
+      *lto_arg_ptr++ = info->name;
+    }
+
+  *lto_arg_ptr++ = NULL;
+  exec_lto_wrapper (lto_argv);
+
+  free (lto_argv);
+
+  if (pass_through_items)
+    {
+      unsigned int i;
+      for (i = 0; i < num_pass_through_items; i++)
+        {
+          add_input_file (pass_through_items[i]);
+          free (pass_through_items[i]);
+          pass_through_items[i] = NULL;
+        }
+      free (pass_through_items);
+      pass_through_items = NULL;
+    }
+
+  return LDPS_OK;
+}
+
+/* Remove temporary files at the end of the link. */
+
+static enum ld_plugin_status
+cleanup_handler (void)
+{
+  int t;
+  unsigned i;
+
+  for (i = 0; i < num_claimed_files; i++)
+    {
+      struct plugin_file_info *info = &claimed_files[i];
+      if (info->temp)
+	{
+	  t = unlink (info->name);
+	  assert (t == 0);
+	}
+    }
+  t = rmdir (temp_obj_dir_name);
+  assert (t == 0);
+
+  free_2 ();
+  return LDPS_OK;
+}
+
+/* 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;
+  struct plugin_file_info lto_file;
+  Elf_Data *symtab;
+  int lto_file_fd;
+
+  if (file->offset != 0)
+    {
+      /* FIXME lto: lto1 should know how to handle archives. */
+      int fd;
+      off_t size = file->filesize;
+      off_t offset;
+
+      static int objnum = 0;
+      char *objname;
+      int t = asprintf (&objname, "%s/obj%d.o",
+			temp_obj_dir_name, objnum);
+      assert (t >= 0);
+      objnum++;
+
+      fd = open (objname, O_RDWR | O_CREAT, 0666);
+      assert (fd > 0);
+      offset = lseek (file->fd, file->offset, SEEK_SET);
+      assert (offset == file->offset);
+      while (size > 0)
+	{
+	  ssize_t r, written;
+	  char buf[1000];
+	  off_t s = sizeof (buf) < size ? sizeof (buf) : size;
+	  r = read (file->fd, buf, s);
+	  written = write (fd, buf, r);
+	  assert (written = r);
+	  size -= r;
+	}
+      lto_file.name = objname;
+      lto_file_fd = fd;
+      lto_file.handle = file->handle;
+      lto_file.temp = 1;
+    }
+  else
+    {
+      lto_file.name = strdup (file->name);
+      lto_file_fd = file->fd;
+      lto_file.handle = file->handle;
+      lto_file.temp = 0;
+    }
+  elf = elf_begin (lto_file_fd, ELF_C_READ, NULL);
+
+  *claimed = 0;
+
+  if (!elf)
+    goto err;
+
+  symtab = get_symtab (elf);
+  if (!symtab)
+    goto err;
+
+  translate (symtab, &lto_file.symtab);
+
+  status = add_symbols (file->handle, lto_file.symtab.nsyms,
+			lto_file.symtab.syms);
+  assert (status == LDPS_OK);
+
+  *claimed = 1;
+  num_claimed_files++;
+  claimed_files =
+    realloc (claimed_files,
+	     num_claimed_files * sizeof (struct plugin_file_info));
+  claimed_files[num_claimed_files - 1] = lto_file;
+
+  goto cleanup;
+
+ err:
+  if (file->offset != 0)
+    {
+      int t = unlink (lto_file.name);
+      assert (t == 0);
+    }
+  free (lto_file.name);
+
+ cleanup:
+  if (elf)
+    elf_end (elf);
+
+  return LDPS_OK;
+}
+
+/* Parse the plugin options. */
+
+static void
+process_option (const char *option)
+{
+  if (strcmp (option, "-debug") == 0)
+    debug = 1;
+  else if (strcmp (option, "-nop") == 0)
+    nop = 1;
+  else if (!strncmp (option, "-pass-through=", strlen("-pass-through=")))
+    {
+      num_pass_through_items++;
+      pass_through_items = realloc (pass_through_items, num_pass_through_items * sizeof (char *));
+      pass_through_items[num_pass_through_items - 1] = strdup (option + strlen ("-pass-through="));
+    }
+  else
+    {
+      int size;
+      lto_wrapper_num_args += 1;
+      size = lto_wrapper_num_args * sizeof (char *);
+      lto_wrapper_argv = (char **) realloc (lto_wrapper_argv, size);
+      lto_wrapper_argv[lto_wrapper_num_args - 1] = strdup(option);
+    }
+}
+
+/* Called by gold after loading the plugin. TV is the transfer vector. */
+
+enum ld_plugin_status
+onload (struct ld_plugin_tv *tv)
+{
+  struct ld_plugin_tv *p;
+  enum ld_plugin_status status;
+  char *t;
+
+  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;
+	case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
+	  register_all_symbols_read = p->tv_u.tv_register_all_symbols_read;
+	  break;
+	case LDPT_GET_SYMBOLS:
+	  get_symbols = p->tv_u.tv_get_symbols;
+	  break;
+	case LDPT_REGISTER_CLEANUP_HOOK:
+	  register_cleanup = p->tv_u.tv_register_cleanup;
+	  break;
+	case LDPT_ADD_INPUT_FILE:
+	  add_input_file = p->tv_u.tv_add_input_file;
+	  break;
+	case LDPT_OPTION:
+	  process_option (p->tv_u.tv_string);
+	  break;
+	default:
+	  break;
+	}
+      p++;
+    }
+
+  assert (register_claim_file);
+  assert (add_symbols);
+  status = register_claim_file (claim_file_handler);
+  assert (status == LDPS_OK);
+
+  if (register_cleanup)
+    {
+      status = register_cleanup (cleanup_handler);
+      assert (status == LDPS_OK);
+    }
+
+  if (register_all_symbols_read)
+    {
+      assert (get_symbols);
+      status = register_all_symbols_read (all_symbols_read_handler);
+      assert (status == LDPS_OK);
+    }
+
+  temp_obj_dir_name = strdup ("tmp_objectsXXXXXX");
+  t = mkdtemp (temp_obj_dir_name);
+  assert (t == temp_obj_dir_name);
+  return LDPS_OK;
+}