[patch] Fix resolution file generation

[Rafael Espindola <espindola at google dot com>]

This patch fixes some of the issues noted on PR 41550. In particular,
it changes from using a file with a hard coded name to using a plugin
argument. It also fixes a bug: get_symbols reads the syms argument to
find if a symbol is a definition or a use. Because of this, we must
pass it the original symbols, not a freshly allocated table.

I tested this by writing the resolution file for a simple case with 2
files. Is there anyway of adding tests like this to the testsuite?
What it has to do is

*) Compile two C files with -flto
*) Run gold with -plugin-opt=-resolution=foo
*) Run grep on foo

I will update the gcc driver in a next patch. Since nothing is using
the resolution file right now, this shouldn't be a problem.

2009-10-14  Rafael Avila de Espindola  <espindola@google.com>

	* lto-plugin.c (resolution_file): New.
	(free_1): Update comment.
	(write_resolution): Write resolution to specified file. Use the
	syms array from the symbol table.
	(all_symbols_read_handler): Delay call to free_1 past call to
	write_resolution.
	(process_option): Add a -resolution option.

Cheers,
-- 
Rafael Ãvila de EspÃndola

diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
index 71b4961..2a18543 100644
--- a/lto-plugin/lto-plugin.c
+++ b/lto-plugin/lto-plugin.c
@@ -97,6 +97,7 @@ static unsigned int num_pass_through_items;
 
 static bool debug;
 static bool nop;
+static char *resolution_file = NULL;
 
 /* 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.
@@ -228,7 +229,8 @@ translate (Elf_Data *symtab, struct plugin_symtab *out)
   out->slots = slots;
 }
 
-/* Free all memory that is no longer needed at the beginning of all_symbols_read. */
+/* Free all memory that is no longer needed after writing the symbol
+   resolution. */
 
 static void
 free_1 (void)
@@ -284,12 +286,11 @@ write_resolution (void)
 {
   unsigned int i;
   FILE *f;
-  /* FIXME: Disabled for now since we are not using the resolution file. */
-  return;
 
+  if (!resolution_file)
+    return;
 
-  /* FIXME: This should be a temporary file. */
-  f = fopen ("resolution", "w");
+  f = fopen (resolution_file, "w");
 
   fprintf (f, "%d\n", num_claimed_files);
 
@@ -297,8 +298,7 @@ write_resolution (void)
     {
       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));
+      struct ld_plugin_symbol *syms = symtab->syms;
       unsigned j;
 
       assert (syms);
@@ -312,7 +312,6 @@ write_resolution (void)
 	  unsigned int resolution = syms[j].resolution;
 	  fprintf (f, "%d %s\n", slot, lto_resolution_str[resolution]);
 	}
-      free (syms);
     }
   fclose (f);
 }
@@ -434,8 +433,6 @@ all_symbols_read_handler (void)
   if (num_claimed_files == 0)
     return LDPS_OK;
 
-  free_1 ();
-
   if (nop)
     {
       use_original_files ();
@@ -448,6 +445,8 @@ all_symbols_read_handler (void)
 
   write_resolution ();
 
+  free_1 ();
+
   for (i = 0; i < lto_wrapper_num_args; i++)
     *lto_arg_ptr++ = lto_wrapper_argv[i];
 
@@ -608,6 +607,10 @@ process_option (const char *option)
     debug = 1;
   else if (strcmp (option, "-nop") == 0)
     nop = 1;
+  else if (!strncmp (option, "-resolution=", strlen("-resolution=")))
+    {
+      resolution_file = strdup (option + strlen("-resolution="));
+    }
   else if (!strncmp (option, "-pass-through=", strlen("-pass-through=")))
     {
       num_pass_through_items++;