I had some trouble with random build failures in a large LTO project
and it turned out to be random seed collisions in a highly parallel build
(thanks to Honza for suggesting that)
There were multiple problems:
- The way to generate the random seed is not very random (milliseconds time plus pid)
and prone to collisions on highly parallel builds
- It's only 32bit
- Several users take the existing ascii seed and re-CRC32 it again, which
doesn't exactly improve it.
This patch changes that to:
- Always use 64bit seeds as numbers (no re-crcing)
- Change all users to use HOST_WIDE_INT
- When the user specifies a random seed it's still crc32ed, but only in
this case.
Passes bootstrap + testsuite on x86_64-linux.
gcc/cp:
2011-09-26 Andi Kleen <ak@linux.intel.com>
* repo.c (finish_repo): Use HOST_WIDE_INT_PRINT_HEX_PURE.
gcc/:
2011-09-26 Andi Kleen <ak@linux.intel.com>
* hwint.h (HOST_WIDE_INT_PRINT_HEX_PURE): Add.
* lto-streamer.c (lto_get_section_name): Remove crc32_string.
Handle numerical random seed.
* lto-streamer.h (lto_file_decl_data): Change id to unsigned HOST_WIDE_INT.
* toplev.c (random_seed): Add.
(init_random_seed): Change for numerical random seed.
(get_random_seed): Return as HOST_WIDE_INT.
(set_random_seed): Crc32 existing string.
* toplev.h (get_random_seed): Change to numercal return.
* tree.c (get_file_function_name): Remove CRC. Handle numerical random seed.
gcc/lto/:
2011-09-26 Andi Kleen <ak@linux.intel.com>
* lto.c (lto_resolution_read): Remove id dumping.
(lto_section_with_id): Turn id HOST_WIDE_ID.
(create_subid_section_table): Dito.
From-SVN: r179347
+2011-09-26 Andi Kleen <ak@linux.intel.com>
+
+ * hwint.h (HOST_WIDE_INT_PRINT_HEX_PURE): Add.
+ * lto-streamer.c (lto_get_section_name): Remove crc32_string.
+ Handle numerical random seed.
+ * lto-streamer.h (lto_file_decl_data): Change id to unsigned HOST_WIDE_INT.
+ * toplev.c (random_seed): Add.
+ (init_random_seed): Change for numerical random seed.
+ (get_random_seed): Return as HOST_WIDE_INT.
+ (set_random_seed): Crc32 existing string.
+ * toplev.h (get_random_seed): Change to numercal return.
+ * tree.c (get_file_function_name): Remove CRC. Handle numerical random seed.
+
2011-09-29 Georg-Johann Lay <avr@gjlay.de>
PR target/50566
+2011-09-26 Andi Kleen <ak@linux.intel.com>
+
+ * repo.c (finish_repo): Use HOST_WIDE_INT_PRINT_HEX_PURE.
+
2011-09-28 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/45278
anonymous namespaces will get the same mangling when this
file is recompiled. */
if (!strstr (args, "'-frandom-seed="))
- fprintf (repo_file, " '-frandom-seed=%s'", get_random_seed (false));
+ fprintf (repo_file, " '-frandom-seed=" HOST_WIDE_INT_PRINT_HEX_PURE "'",
+ get_random_seed (false));
fprintf (repo_file, "\n");
}
#define HOST_WIDE_INT_PRINT_DEC_C HOST_WIDE_INT_PRINT_DEC HOST_WIDE_INT_PRINT_C
#define HOST_WIDE_INT_PRINT_UNSIGNED "%" HOST_WIDE_INT_PRINT "u"
#define HOST_WIDE_INT_PRINT_HEX "%#" HOST_WIDE_INT_PRINT "x"
+#define HOST_WIDE_INT_PRINT_HEX_PURE "%" HOST_WIDE_INT_PRINT "x"
/* Set HOST_WIDEST_INT. This is a 64-bit type unless the compiler
in use has no 64-bit type at all; in that case it's 32 bits. */
doesn't confuse the reader with merged sections.
For options don't add a ID, the option reader cannot deal with them
- and merging should be ok here.
-
- XXX: use crc64 to minimize collisions? */
+ and merging should be ok here. */
if (section_type == LTO_section_opts)
strcpy (post, "");
+ else if (f != NULL)
+ sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, f->id);
else
- sprintf (post, ".%x", f ? f->id : crc32_string(0, get_random_seed (false)));
+ sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, get_random_seed (false));
return concat (LTO_SECTION_NAME_PREFIX, sep, add, post, NULL);
}
struct lto_file_decl_data *next;
/* Sub ID for merged objects. */
- unsigned id;
+ unsigned HOST_WIDE_INT id;
/* Symbol resolutions for this file */
VEC(ld_plugin_symbol_resolution_t,heap) * GTY((skip)) resolutions;
+2011-09-26 Andi Kleen <ak@linux.intel.com>
+
+ * lto.c (lto_resolution_read): Remove id dumping.
+ (lto_section_with_id): Turn id HOST_WIDE_ID.
+ (create_subid_section_table): Dito.
+
2011-08-28 Dodji Seketeli <dodji@redhat.com>
* lto-lang.c (lto_init): Likewise. Also, avoid calling
}
file_data = (struct lto_file_decl_data *)nd->value;
- if (cgraph_dump_file)
- fprintf (cgraph_dump_file, "Adding resolution %u %u to id %x\n",
- index, r, file_data->id);
VEC_safe_grow_cleared (ld_plugin_symbol_resolution_t, heap,
file_data->resolutions,
max_index + 1);
/* Is the name for a id'ed LTO section? */
static int
-lto_section_with_id (const char *name, unsigned *id)
+lto_section_with_id (const char *name, unsigned HOST_WIDE_INT *id)
{
const char *s;
if (strncmp (name, LTO_SECTION_NAME_PREFIX, strlen (LTO_SECTION_NAME_PREFIX)))
return 0;
s = strrchr (name, '.');
- return s && sscanf (s, ".%x", id) == 1;
+ return s && sscanf (s, "." HOST_WIDE_INT_PRINT_HEX_PURE, id) == 1;
}
/* Create file_data of each sub file id */
struct lto_section_slot s_slot, *new_slot;
struct lto_section_slot *ls = *(struct lto_section_slot **)slot;
splay_tree file_ids = (splay_tree)data;
- unsigned id;
+ unsigned HOST_WIDE_INT id;
splay_tree_node nd;
void **hash_slot;
char *new_name;
lto_file_finalize (file_data, lw->file);
if (cgraph_dump_file)
- fprintf (cgraph_dump_file, "Creating file %s with sub id %x\n",
+ fprintf (cgraph_dump_file, "Creating file %s with sub id " HOST_WIDE_INT_PRINT_HEX "\n",
file_data->file_name, file_data->id);
file_data->next = *lw->file_data;
*lw->file_data = file_data;
user has specified a particular random seed. */
unsigned local_tick;
+/* Random number for this compilation */
+HOST_WIDE_INT random_seed;
+
/* -f flags. */
/* Generate code for GNU or NeXT Objective-C runtime environment. */
}
}
-/* Initialize local_tick with the time of day, or -1 if
+/* Initialize local_tick with a random number or -1 if
flag_random_seed is set. */
static void
static void
init_random_seed (void)
{
- unsigned HOST_WIDE_INT value;
- static char random_seed[HOST_BITS_PER_WIDE_INT / 4 + 3];
-
- value = local_tick ^ getpid ();
+ if (flag_random_seed)
+ {
+ char *endp;
- sprintf (random_seed, HOST_WIDE_INT_PRINT_HEX, value);
- flag_random_seed = random_seed;
+ /* When the driver passed in a hex number don't crc it again */
+ random_seed = strtoul (flag_random_seed, &endp, 0);
+ if (!(endp > flag_random_seed && *endp == 0))
+ random_seed = crc32_string (0, flag_random_seed);
+ }
+ else if (!random_seed)
+ random_seed = local_tick ^ getpid (); /* Old racey fallback method */
}
-/* Obtain the random_seed string. Unless NOINIT, initialize it if
+/* Obtain the random_seed. Unless NOINIT, initialize it if
it's not provided in the command line. */
-const char *
+HOST_WIDE_INT
get_random_seed (bool noinit)
{
if (!flag_random_seed && !noinit)
init_random_seed ();
- return flag_random_seed;
+ return random_seed;
}
/* Modify the random_seed string to VAL. Return its previous
/* Functions used to manipulate the random seed. */
-extern const char *get_random_seed (bool);
+extern HOST_WIDE_INT get_random_seed (bool);
extern const char *set_random_seed (const char *);
#endif /* ! GCC_TOPLEV_H */
file = input_filename;
len = strlen (file);
- q = (char *) alloca (9 * 2 + len + 1);
+ q = (char *) alloca (9 + 17 + len + 1);
memcpy (q, file, len + 1);
- sprintf (q + len, "_%08X_%08X", crc32_string (0, name),
- crc32_string (0, get_random_seed (false)));
+ snprintf (q + len, 9 + 17 + 1, "_%08X_" HOST_WIDE_INT_PRINT_HEX,
+ crc32_string (0, name), get_random_seed (false));
p = q;
}
projects / thirdparty / gcc.git / commitdiff
