Merge pull request #642 from Safety0ff/gcismarkedfix

Fix #10701 & 10838

Author: MartinNowak

src/gc/gc.d

@@ -1647,6 +1647,7 @@ struct Gcx
             else
             {
                 // we are in a B_FREE page
+                assert(bin == B_FREE);
                 return null;
             }
         }
@@ -2324,6 +2325,7 @@ struct Gcx
                     else
                     {
                         // Don't mark bits in B_FREE pages
+                        assert(bin == B_FREE);
                         continue;
                     }
 
@@ -2630,7 +2632,7 @@ struct Gcx
                                 toClear |= GCBits.BITS_1 << clearIndex;
 
                                 List *list = cast(List *)p;
-                                debug(PRINTF) printf("\tcollecting %p\n", list);
+                                debug(COLLECT_PRINTF) printf("\tcollecting %p\n", list);
                                 log_free(sentinel_add(list));
 
                                 debug (MEMSTOMP) memset(p, 0xF3, size);
@@ -2744,11 +2746,16 @@ struct Gcx
             {
                 biti = (offset & notbinsize[bins]) >> pool.shiftBy;
             }
-            else
+            else if(bins == B_PAGEPLUS)
             {
                 pn -= pool.bPageOffsets[pn];
                 biti = pn * (PAGESIZE >> pool.shiftBy);
             }
+            else // bins == B_FREE
+            {
+                assert(bins == B_FREE);
+                return IsMarked.no;
+            }
             return pool.mark.test(biti) ? IsMarked.yes : IsMarked.no;
         }
         return IsMarked.unknown;

src/rt/lifetime.d

@@ -421,6 +421,15 @@ void processGCMarks(BlkInfo* cache, scope rt.tlsgc.IsMarkedDg isMarked)
     }
 }
 
+unittest
+{
+    import core.memory;
+    // Bugzilla 10701 - segfault in GC
+    ubyte[] result; result.length = 4096;
+    GC.free(result.ptr);
+    GC.collect();
+}
+
 /**
   Get the cached block info of an interior pointer.  Returns null if the
   interior pointer's block is not cached.