ld: Avoid overflows in string merging

as the bug report shows we had an overflow in the test if
hash table resizing is needed.  Reorder the expression to avoid
that.  There's still a bug somewhere in gracefully handling
failure in resizing (e.g. out of memory), but this pushes the
boundary for that occurring somewhen into the future and
immediately helps the reporter.

    bfd/

    PR ld/31009
    * merge.c (NEEDS_RESIZE): New macro avoiding overflow.
    (sec_merge_maybe_resize): Use it.
    (sec_merge_hash_insert): Ditto.

diff --git a/bfd/merge.c b/bfd/merge.c
index 722e665948627cbee4b5215d9011137713604f00..61ffab4d706c0e063097877e2578172a309e228d 100644 (file)
--- a/bfd/merge.c
+++ b/bfd/merge.c
@@ -94,6 +94,10 @@ struct sec_merge_hash
   struct sec_merge_hash_entry **values;
 };
 
+/* True when given NEWCOUNT and NBUCKETS indicate that the hash table needs
+   resizing.  */
+#define NEEDS_RESIZE(newcount, nbuckets) ((newcount) > (nbuckets) / 3 * 2)
+
 struct sec_merge_sec_info;
 
 /* Information per merged blob.  This is the unit of merging and is
@@ -167,7 +171,7 @@ static bool
 sec_merge_maybe_resize (struct sec_merge_hash *table, unsigned added)
 {
   struct bfd_hash_table *bfdtab = &table->table;
-  if (bfdtab->count + added > table->nbuckets * 2 / 3)
+  if (NEEDS_RESIZE (bfdtab->count + added, table->nbuckets))
     {
       unsigned i;
       unsigned long newnb = table->nbuckets * 2;
@@ -175,7 +179,7 @@ sec_merge_maybe_resize (struct sec_merge_hash *table, unsigned added)
       uint64_t *newl;
       unsigned long alloc;
 
-      while (bfdtab->count + added > newnb * 2 / 3)
+      while (NEEDS_RESIZE (bfdtab->count + added, newnb))
        {
          newnb *= 2;
          if (!newnb)
@@ -239,8 +243,8 @@ sec_merge_hash_insert (struct sec_merge_hash *table,
   hashp->alignment = 0;
   hashp->u.suffix = NULL;
   hashp->next = NULL;
-  // We must not need resizing, otherwise _index is wrong
-  BFD_ASSERT (bfdtab->count + 1 <= table->nbuckets * 2 / 3);
+  // We must not need resizing, otherwise the estimation was wrong
+  BFD_ASSERT (!NEEDS_RESIZE (bfdtab->count + 1, table->nbuckets));
   bfdtab->count++;
   table->key_lens[_index] = (hash << 32) | (uint32_t)len;
   table->values[_index] = hashp;