[patch] Use LDPL_FATAL instead of assert

[Rafael Espindola <espindola at google dot com>]

The plugin currently asserts on all errors. This patch changes most of them
into calls to the message callback. The patch also makes the cleanup_handler
succeed when being called in consequence of an earlier error.

2009-10-15  Rafael Avila de Espindola  <espindola@google.com>

	* lto-plugin.c (message): New variable.
	(check): New function.
	(parse_table_entry, translate, write_resolution,add_output_files,
	exec_lto_wrapper,claim_file_handler, onload): Use check instead of
	assert.
	(cleanup_handler): Use check instead of assert. Remove the arguments
	file if it exists.

Cheers,
-- 
Rafael Ãvila de EspÃndola

diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
index ae484a9..bfb9925 100644
--- a/lto-plugin/lto-plugin.c
+++ b/lto-plugin/lto-plugin.c
@@ -82,6 +82,7 @@ static ld_plugin_get_symbols get_symbols;
 static ld_plugin_register_cleanup register_cleanup;
 static ld_plugin_add_input_file add_input_file;
 static ld_plugin_add_input_library add_input_library;
+static ld_plugin_message message;
 
 static struct plugin_file_info *claimed_files = NULL;
 static unsigned int num_claimed_files = 0;
@@ -99,6 +100,23 @@ static bool debug;
 static bool nop;
 static char *resolution_file = NULL;
 
+static void
+check (bool gate, enum ld_plugin_level level, const char *text)
+{
+  if (gate)
+    return;
+
+  if (message)
+    message (level, text);
+  else
+    {
+      /* If there is no nicer way to inform the user, fallback to stderr. */
+      fprintf (stderr, "%s\n", text);
+      if (level == LDPL_FATAL)
+	abort ();
+    }
+}
+
 /* 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. */
@@ -142,12 +160,12 @@ parse_table_entry (char *p, struct ld_plugin_symbol *entry, uint32_t *slot)
     entry->comdat_key = strdup (entry->comdat_key);
 
   t = *p;
-  assert (t <= 4);
+  check (t <= 4, LDPL_FATAL, "Invalid symbol kind found.");
   entry->def = translate_kind[t];
   p++;
 
   t = *p;
-  assert (t <= 3);
+  check (t <= 3, LDPL_FATAL, "Invalid symbol visibility found.");
   entry->visibility = translate_visibility[t];
   p++;
 
@@ -218,9 +236,9 @@ translate (Elf_Data *symtab, struct plugin_symtab *out)
     {
       n++;
       syms = realloc (syms, n * sizeof (struct ld_plugin_symbol));
-      assert (syms);
+      check (syms, LDPL_FATAL, "Could not allocate memory.");
       slots = realloc (slots, n * sizeof (uint32_t));
-      assert (slots);
+      check (slots, LDPL_FATAL, "Could not allocate memory.");
       data = parse_table_entry (data, &syms[n - 1], &slots[n - 1]);
     }
 
@@ -297,7 +315,7 @@ write_resolution (void)
     return;
 
   f = fopen (resolution_file, "w");
-  assert (f);
+  check (f, LDPL_FATAL, "Could not open file.");
 
   fprintf (f, "%d\n", num_claimed_files);
 
@@ -329,7 +347,7 @@ write_resolution (void)
 static void
 add_output_files (FILE *f)
 {
-  char fname[1000]; /* FIXME: Is this big enough? */
+  char fname[1000]; /* FIXME: Remove this restriction. */
 
   for (;;)
     {
@@ -339,7 +357,7 @@ add_output_files (FILE *f)
 	break;
 
       len = strlen (s);
-      assert (s[len - 1] == '\n');
+      check (s[len - 1] == '\n', LDPL_FATAL, "File name too long.");
       s[len - 1] = '\0';
 
       num_output_files++;
@@ -367,16 +385,16 @@ exec_lto_wrapper (char *argv[])
 
   /* 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);
+  check (t >= 0, LDPL_FATAL, "asprintf failed.");
 
   args_name = at_args + 1;
   args = fopen (args_name, "w");
-  assert (args);
+  check (args, LDPL_FATAL, "Could not open arguments file.");
 
   t = writeargv (&argv[1], args);
-  assert (t == 0);
+  check (t == 0, LDPL_FATAL, "Could not write arguments.");
   t = fclose (args);
-  assert (t == 0);
+  check (t == 0, LDPL_FATAL, "Could not close arguments file.");
 
   new_argv[0] = argv[0];
   new_argv[1] = at_args;
@@ -392,25 +410,26 @@ exec_lto_wrapper (char *argv[])
 
 
   pex = pex_init (PEX_USE_PIPES, "lto-wrapper", NULL);
-  assert (pex != NULL);
+  check (pex != NULL, LDPL_FATAL, "Could not pex_init lto-wrapper.");
 
   errmsg = pex_run (pex, 0, new_argv[0], new_argv, NULL, NULL, &t);
-  assert (errmsg == NULL);
-  assert (t == 0);
+  check (errmsg == NULL, LDPL_FATAL, "Could not run lto-wrapper.");
+  check (t == 0, LDPL_FATAL, "Could not run lto-wrapper.");
 
   wrapper_output = pex_read_output (pex, 0);
-  assert (wrapper_output);
+  check (wrapper_output, LDPL_FATAL, "Could not read lto-wrapper output.");
 
   add_output_files (wrapper_output);
 
   t = pex_get_status (pex, 1, &status);
-  assert (t == 1);
-  assert (WIFEXITED (status) && WEXITSTATUS (status) == 0);
+  check (t == 1, LDPL_FATAL, "Could not get lto-wrapper exit status.");
+  check (WIFEXITED (status) && WEXITSTATUS (status) == 0,
+	 LDPL_FATAL,          "lto-wrapper failed.");
 
   pex_free (pex);
 
   t = unlink (args_name);
-  assert (t == 0);
+  check (t == 0, LDPL_FATAL, "Could not unlink arguments file.");
   free (at_args);
 }
 
@@ -493,8 +512,12 @@ all_symbols_read_handler (void)
 static enum ld_plugin_status
 cleanup_handler (void)
 {
+  /* Note: we cannot use LDPL_FATAL in here as that would produce
+     an infinite loop. */
   int t;
   unsigned i;
+  char *arguments;
+  struct stat buf;
 
   for (i = 0; i < num_claimed_files; i++)
     {
@@ -502,11 +525,23 @@ cleanup_handler (void)
       if (info->temp)
 	{
 	  t = unlink (info->name);
-	  assert (t == 0);
+	  check (t == 0, LDPL_ERROR, "Could not unlink temporary file.");
 	}
     }
+
+  /* If we are being called from an error handler, it is possible
+     that the arguments file is still exists. */
+  t = asprintf (&arguments, "%s/arguments", temp_obj_dir_name);
+  check (t >= 0, LDPL_ERROR, "asprintf failed.");
+  if (stat(arguments, &buf) == 0)
+    {
+      t = unlink (arguments);
+      check (t == 0, LDPL_ERROR, "Could not unlink arguments file.");
+    }
+  free (arguments);
+
   t = rmdir (temp_obj_dir_name);
-  assert (t == 0);
+  check (t == 0, LDPL_ERROR, "Could not remove temporary directory.");
 
   free_2 ();
   return LDPS_OK;
@@ -535,13 +570,13 @@ claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
       char *objname;
       int t = asprintf (&objname, "%s/obj%d.o",
 			temp_obj_dir_name, objnum);
-      assert (t >= 0);
+      check (t >= 0, LDPL_FATAL, "asprintf failed.");
       objnum++;
 
       fd = open (objname, O_RDWR | O_CREAT, 0666);
-      assert (fd > 0);
+      check (fd > 0, LDPL_FATAL, "Could not open/create temporary file.");
       offset = lseek (file->fd, file->offset, SEEK_SET);
-      assert (offset == file->offset);
+      check (offset == file->offset, LDPL_FATAL, "Could not seek.");
       while (size > 0)
 	{
 	  ssize_t r, written;
@@ -549,7 +584,8 @@ claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
 	  off_t s = sizeof (buf) < size ? sizeof (buf) : size;
 	  r = read (file->fd, buf, s);
 	  written = write (fd, buf, r);
-	  assert (written = r);
+	  check (written == r, LDPL_FATAL,
+		 "Could not write to temporary file.");
 	  size -= r;
 	}
       lto_file.name = objname;
@@ -579,7 +615,7 @@ claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
 
   status = add_symbols (file->handle, lto_file.symtab.nsyms,
 			lto_file.symtab.syms);
-  assert (status == LDPS_OK);
+  check (status == LDPS_OK, LDPL_FATAL, "Could not add symbols.");
 
   *claimed = 1;
   num_claimed_files++;
@@ -594,7 +630,7 @@ claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
   if (file->offset != 0)
     {
       int t = unlink (lto_file.name);
-      assert (t == 0);
+      check (t == 0, LDPL_FATAL, "Could not unlink file.");
     }
   free (lto_file.name);
 
@@ -646,13 +682,16 @@ onload (struct ld_plugin_tv *tv)
   char *t;
 
   unsigned version = elf_version (EV_CURRENT);
-  assert (version != EV_NONE);
+  check (version != EV_NONE, LDPL_FATAL, "Invalid elf version.");
 
   p = tv;
   while (p->tv_tag)
     {
       switch (p->tv_tag)
 	{
+        case LDPT_MESSAGE:
+          message = p->tv_u.tv_message;
+          break;
 	case LDPT_REGISTER_CLAIM_FILE_HOOK:
 	  register_claim_file = p->tv_u.tv_register_claim_file;
 	  break;
@@ -683,22 +722,25 @@ onload (struct ld_plugin_tv *tv)
       p++;
     }
 
-  assert (register_claim_file);
-  assert (add_symbols);
+  check (register_claim_file, LDPL_FATAL, "register_claim_file not found.");
+  check (add_symbols, LDPL_FATAL, "add_symbols not found.");
   status = register_claim_file (claim_file_handler);
-  assert (status == LDPS_OK);
+  check (status == LDPS_OK, LDPL_FATAL,
+	 "Could not register the claim_file callback.");
 
   if (register_cleanup)
     {
       status = register_cleanup (cleanup_handler);
-      assert (status == LDPS_OK);
+      check (status == LDPS_OK, LDPL_FATAL,
+	     "Could not register the cleanup callback.");
     }
 
   if (register_all_symbols_read)
     {
-      assert (get_symbols);
+      check (get_symbols, LDPL_FATAL, "get_symbols not found.");
       status = register_all_symbols_read (all_symbols_read_handler);
-      assert (status == LDPS_OK);
+      check (status == LDPS_OK, LDPL_FATAL,
+	     "Could not register the all_symbols_read callback.");
     }
 
   temp_obj_dir_name = strdup ("tmp_objectsXXXXXX");