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-rw-r--r--lto-plugin/lto-plugin.c689
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 000000000000..a0c1a54e0e2a
--- /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;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-10 16:52:48 +0000