[Mono-bugs] [Bug 77787][Wis] Changed - Mono fails on Itanium-machine

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Changed by yury at serdyuk.botik.ru.

http://bugzilla.ximian.com/show_bug.cgi?id=77787

--- shadow/77787	2006-05-11 09:51:35.000000000 -0400
+++ shadow/77787.tmp.13601	2006-05-12 04:13:00.000000000 -0400
@@ -1061,6 +1061,89 @@
 
 ------- Additional Comments From vargaz at gmail.com  2006-05-11 09:51 -------
 So the problem here is that GC_base(obj) returns 0, which it shouldn't.
 Could you step into the GC_base () call with gdb to see why it
 returns that ?
 
+
+------- Additional Comments From Yury at serdyuk.botik.ru  2006-05-12 04:12 -------
+I did not understand how GC_base was run.
+Is it consequence of optimization ?
+
+Starting program: /home/users/gramuser2/m-1.1.14/bin/mono
+/home/users/gramuser2/m-1.1.14/lib/mono/1.0/mcs.exe
+[Thread debugging using libthread_db enabled]
+[New Thread 2305843009219573216 (LWP 11785)]
+[Switching to Thread 2305843009219573216 (LWP 11785)]
+
+Breakpoint 3, GC_base (p=<value optimized out>) at misc.c:395
+395         r = (word)p;
+(gdb) l
+390         register struct hblk *h;
+391         register bottom_index *bi;
+392         register hdr *candidate_hdr;
+393         register word limit;
+394
+395         r = (word)p;
+396         if (!GC_is_initialized) return 0;
+397         h = HBLKPTR(r);
+398         GET_BI(r, bi);
+399         candidate_hdr = HDR_FROM_BI(bi, r);
+(gdb)
+400         if (candidate_hdr == 0) return(0);
+401         /* If it's a pointer to the middle of a large object, move
+it       */
+402         /* to the beginning.                                     
+          */
+403             while (IS_FORWARDING_ADDR_OR_NIL(candidate_hdr)) {
+404                h = FORWARDED_ADDR(h,candidate_hdr);
+405                r = (word)h;
+406                candidate_hdr = HDR(h);
+407             }
+408         if (candidate_hdr -> hb_map == GC_invalid_map) return(0);
+409         /* Make sure r points to the beginning of the object */
+(gdb)
+410             r &= ~(WORDS_TO_BYTES(1) - 1);
+411             {
+412                 register int offset = HBLKDISPL(r);
+413                 register signed_word sz = candidate_hdr -> hb_sz;
+414                 register signed_word map_entry;
+415
+416                 map_entry = MAP_ENTRY((candidate_hdr -> hb_map),
+offset);
+417                 if (map_entry > CPP_MAX_OFFSET) {
+418                     map_entry =
+(signed_word)(BYTES_TO_WORDS(offset)) % sz;
+419                 }
+(gdb)
+420                 r -= WORDS_TO_BYTES(map_entry);
+421                 limit = r + WORDS_TO_BYTES(sz);
+422                 if (limit > (word)(h + 1)
+423                     && sz <= BYTES_TO_WORDS(HBLKSIZE)) {
+424                     return(0);
+425                 }
+426                 if ((word)p >= limit) return(0);
+427             }
+428         return((GC_PTR)r);
+429     }
+(gdb) display r
+1: r = 6917529027641185568
+(gdb) n
+398         GET_BI(r, bi);
+1: r = 6917529027641185568
+(gdb) n
+396         if (!GC_is_initialized) return 0;
+1: r = 6917529027641185568
+(gdb) n
+397         h = HBLKPTR(r);
+1: r = 6917529027641185568
+(gdb) n
+396         if (!GC_is_initialized) return 0;
+1: r = 6917529027641185568
+(gdb) n
+424                     return(0);
+1: r = 6917529027641185568
+(gdb) n
+429     }
+1: r = 6917529027641185568
+(gdb)
+