[Bug preprocessor/14699] New: abort() in hashtable.c in approx_sqrt() with -fmem-report

[Bug preprocessor/14699] New: abort() in hashtable.c in approx_sqrt() with -fmem-report

[1319 at bot dot ru]

$ echo 'int ' > bug.c
$ tr '\0' a < /dev/zero | head -c 65536 >> bug.c
$ echo ';' >> bug.c
$ gcc-3.3 -S -fmem-report bug.c

Tree                 Number            Bytes    % Total
Total                     0               0 

RTX                  Number            Bytes    % Total
Total                     0               0 

Size   Allocated        Used    Overhead
8           8192        7824         184 
16          4096          64          60 
32          8192        5952          88 
64            36k         33k        324 
256         4096        1792          28 
512           28k         26k        196 
1024        8192        7168          56 
112           84k         80k        672 
20            16k         12k        208 
12          8192        5976         136 
44          4096         528          36 
Total        208k        181k       1988 

String pool
entries         532
identifiers     532 (100.00%)
slots           16384
bytes           69k (2353  overhead)
table size      64k
coll/search     0.0182
ins/search      0.8061
bug.c:2: internal compiler error: Aborted
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.


The bug is actually in function ht_dump_statistics() in very broken code that
calculates average entry size deviation. The code is broken because it does not
takes into account 32 bit wide size_t (sum_of_squares += n * n and n here >=
65536), and it calculates standart deviation of entry size using wrong formula.

Here is a patch (against 3_4-branch or mainline):

diff -u hashtable.c.~1.16.~ hashtable.c
--- hashtable.c.~1.16.~	2003-08-23 02:29:17.000000000 +0400
+++ hashtable.c	2004-03-24 00:59:56.975755952 +0300
@@ -228,11 +228,11 @@
 ht_dump_statistics (hash_table *table)
 {
   size_t nelts, nids, overhead, headers;
-  size_t total_bytes, longest, sum_of_squares;
-  double exp_len, exp_len2, exp2_len;
+  size_t longest;
+  double total_bytes, sum_of_squares, exp2_sd;
   hashnode *p, *limit;
 
-#define SCALE(x) ((unsigned long) ((x) < 1024*10 \
+#define SCALE(x) (((x) < 1024*10 \
 		  ? (x) \
 		  : ((x) < 1024*1024*10 \
 		     ? (x) / 1024 \
@@ -247,16 +247,19 @@
       {
 	size_t n = HT_LEN (*p);
 
-	total_bytes += n;
-	sum_of_squares += n * n;
+	total_bytes += (double) n;
+	sum_of_squares += (double) n * (double) n;
 	if (n > longest)
 	  longest = n;
 	nids++;
       }
   while (++p < limit);
-
+  
+  exp2_sd = (sum_of_squares - total_bytes * total_bytes / nids)
+	  / (double) (nids - 1);
+  
   nelts = table->nelements;
-  overhead = obstack_memory_used (&table->stack) - total_bytes;
+  overhead = obstack_memory_used (&table->stack) - (size_t) total_bytes;
   headers = table->nslots * sizeof (hashnode);
 
   fprintf (stderr, "\nString pool\nentries\t\t%lu\n",
@@ -265,22 +268,17 @@
 	   (unsigned long) nids, nids * 100.0 / nelts);
   fprintf (stderr, "slots\t\t%lu\n",
 	   (unsigned long) table->nslots);
-  fprintf (stderr, "bytes\t\t%lu%c (%lu%c overhead)\n",
+  fprintf (stderr, "bytes\t\t%.0f%c (%lu%c overhead)\n",
 	   SCALE (total_bytes), LABEL (total_bytes),
-	   SCALE (overhead), LABEL (overhead));
+	   (unsigned long) SCALE (overhead), LABEL (overhead));
   fprintf (stderr, "table size\t%lu%c\n",
-	   SCALE (headers), LABEL (headers));
-
-  exp_len = (double)total_bytes / (double)nelts;
-  exp2_len = exp_len * exp_len;
-  exp_len2 = (double) sum_of_squares / (double) nelts;
-
+	   (unsigned long) SCALE (headers), LABEL (headers));
   fprintf (stderr, "coll/search\t%.4f\n",
 	   (double) table->collisions / (double) table->searches);
   fprintf (stderr, "ins/search\t%.4f\n",
 	   (double) nelts / (double) table->searches);
   fprintf (stderr, "avg. entry\t%.2f bytes (+/- %.2f)\n",
-	   exp_len, approx_sqrt (exp_len2 - exp2_len));
+	   total_bytes / nids, approx_sqrt (exp2_sd));
   fprintf (stderr, "longest entry\t%lu\n",
 	   (unsigned long) longest);
 #undef SCALE

-- 
           Summary: abort() in hashtable.c in approx_sqrt() with -fmem-
                    report
           Product: gcc
           Version: 3.3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: 1319 at bot dot ru
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[1319 at bot dot ru]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |3.3.4 3.4.0 3.5.0 tree-ssa
                   |                            |lno


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[1319 at bot dot ru]

------- Additional Comments From 1319 at bot dot ru  2004-03-23 22:23 -------
Created an attachment (id=5984)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5984&action=view)
same patch generated by cvs diff


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-23 22:59 -------
Confirmed. Could you send your patch gcc-patches@gcc.gnu.org ___after___ reading http://
gcc.gnu.org/contribute.html.  Thanks.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
      Known to fail|3.3.4 3.4.0 3.5.0 tree-ssa  |3.3.4 3.4.0 3.5.0 tree-ssa
                   |lno                         |lno 3.3.1 3.2.3 3.0.4
   Last reconfirmed|0000-00-00 00:00:00         |2004-03-23 22:59:04
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[1319 at bot dot ru]

------- Additional Comments From 1319 at bot dot ru  2004-03-24 04:26 -------
patch here: <http://gcc.gnu.org/ml/gcc-patches/2004-03/msg01961.html>

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-09-06 14:44 -------
Fixed now, thakns Serge for the patch and Paolo for committing it.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-09-06 13:22 -------
Subject: Bug 14699

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	bonzini@gcc.gnu.org	2004-09-06 13:22:49

Modified files:
	libcpp         : ChangeLog symtab.c 

Log message:
	2004-09-06  Serge Belyshev  <belyshev@lubercy.com>
	
	PR preprocessor/14699
	* symtab.c (ht_dump_statistics): Change type of sum_of_squares
	from size_t to double.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libcpp/ChangeLog.diff?cvsroot=gcc&r1=1.24&r2=1.25
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libcpp/symtab.c.diff?cvsroot=gcc&r1=1.3&r2=1.4



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[belyshev at lubercy dot com]

------- Additional Comments From belyshev at lubercy dot com  2004-06-26 14:08 -------
updated patch: http://gcc.gnu.org/ml/gcc-patches/2004-06/msg02184.html

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699

[Bug preprocessor/14699] abort() in hashtable.c in approx_sqrt() with -fmem-report

[belyshev at lubercy dot com]

------- Additional Comments From belyshev at lubercy dot com  2004-05-04 16:56 -------
An updated patch here: http://gcc.gnu.org/ml/gcc-patches/2004-03/msg02049.html


2004-05-04  Serge Belyshev  <belyshev@lubercy.com>

	PR 14699
        * hashtable.c (ht_dump_statistics): Change type of sum_of_squares
        from size_t to double.

diff -u hashtable.c.~1.16.~ hashtable.c
--- hashtable.c.~1.16.~	2003-08-23 02:29:17.000000000 +0400
+++ hashtable.c	2004-03-25 01:37:01.998704560 +0300
@@ -228,8 +228,8 @@
 ht_dump_statistics (hash_table *table)
 {
   size_t nelts, nids, overhead, headers;
-  size_t total_bytes, longest, sum_of_squares;
-  double exp_len, exp_len2, exp2_len;
+  size_t total_bytes, longest;
+  double exp_len, exp_len2, exp2_len, sum_of_squares;
   hashnode *p, *limit;
 
 #define SCALE(x) ((unsigned long) ((x) < 1024*10 \
@@ -248,7 +248,7 @@
 	size_t n = HT_LEN (*p);
 
 	total_bytes += n;
-	sum_of_squares += n * n;
+	sum_of_squares += (double) n * n;
 	if (n > longest)
 	  longest = n;
 	nids++;


Can anyone apply it as it was approved by Zack in
http://gcc.gnu.org/ml/gcc-patches/2004-03/msg02117.html ?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14699