PR29626, Segfault when disassembling ARM code

	PR 29626
	* arm-dis.c (mapping_symbol_for_insn): Return false on zero
	symtab_size.  Delete later symtab_size test.

diff --git a/opcodes/arm-dis.c b/opcodes/arm-dis.c
index 684c74f7f20854dd9ac16eb2bc7b402e9bb28a24..caf3531ae3d5e1d556e8a586151e7e17925f5721 100644 (file)
--- a/opcodes/arm-dis.c
+++ b/opcodes/arm-dis.c
@@ -11865,77 +11865,75 @@ mapping_symbol_for_insn (bfd_vma pc, struct disassemble_info *info,
   struct arm_private_data *private_data;
 
   if (info->private_data == NULL
+      || info->symtab_size == 0
       || bfd_asymbol_flavour (*info->symtab) != bfd_target_elf_flavour)
     return false;
 
   private_data = info->private_data;
 
   /* First, look for mapping symbols.  */
-  if (info->symtab_size != 0)
-  {
-    if (pc <= private_data->last_mapping_addr)
-      private_data->last_mapping_sym = -1;
-
-    /* Start scanning at the start of the function, or wherever
-       we finished last time.  */
-    n = info->symtab_pos + 1;
-
-    /* If the last stop offset is different from the current one it means we
-       are disassembling a different glob of bytes.  As such the optimization
-       would not be safe and we should start over.  */
-    can_use_search_opt_p
-      = private_data->last_mapping_sym >= 0
-       && info->stop_offset == private_data->last_stop_offset;
-
-    if (n >= private_data->last_mapping_sym && can_use_search_opt_p)
-      n = private_data->last_mapping_sym;
-
-    /* Look down while we haven't passed the location being disassembled.
-       The reason for this is that there's no defined order between a symbol
-       and an mapping symbol that may be at the same address.  We may have to
-       look at least one position ahead.  */
-    for (; n < info->symtab_size; n++)
-      {
-       addr = bfd_asymbol_value (info->symtab[n]);
-       if (addr > pc)
-         break;
-       if (get_map_sym_type (info, n, &type))
-         {
-           last_sym = n;
-           found = true;
-         }
-      }
+  if (pc <= private_data->last_mapping_addr)
+    private_data->last_mapping_sym = -1;
+
+  /* Start scanning at the start of the function, or wherever
+     we finished last time.  */
+  n = info->symtab_pos + 1;
+
+  /* If the last stop offset is different from the current one it means we
+     are disassembling a different glob of bytes.  As such the optimization
+     would not be safe and we should start over.  */
+  can_use_search_opt_p
+    = (private_data->last_mapping_sym >= 0
+       && info->stop_offset == private_data->last_stop_offset);
+
+  if (n >= private_data->last_mapping_sym && can_use_search_opt_p)
+    n = private_data->last_mapping_sym;
+
+  /* Look down while we haven't passed the location being disassembled.
+     The reason for this is that there's no defined order between a symbol
+     and an mapping symbol that may be at the same address.  We may have to
+     look at least one position ahead.  */
+  for (; n < info->symtab_size; n++)
+    {
+      addr = bfd_asymbol_value (info->symtab[n]);
+      if (addr > pc)
+       break;
+      if (get_map_sym_type (info, n, &type))
+       {
+         last_sym = n;
+         found = true;
+       }
+    }
 
-    if (!found)
-      {
-       n = info->symtab_pos;
-       if (n >= private_data->last_mapping_sym && can_use_search_opt_p)
-         n = private_data->last_mapping_sym;
-
-       /* No mapping symbol found at this address.  Look backwards
-          for a preceeding one, but don't go pass the section start
-          otherwise a data section with no mapping symbol can pick up
-          a text mapping symbol of a preceeding section.  The documentation
-          says section can be NULL, in which case we will seek up all the
-          way to the top.  */
-       if (info->section)
-         section_vma = info->section->vma;
-
-       for (; n >= 0; n--)
-         {
-           addr = bfd_asymbol_value (info->symtab[n]);
-           if (addr < section_vma)
-             break;
+  if (!found)
+    {
+      n = info->symtab_pos;
+      if (n >= private_data->last_mapping_sym && can_use_search_opt_p)
+       n = private_data->last_mapping_sym;
+
+      /* No mapping symbol found at this address.  Look backwards
+        for a preceeding one, but don't go pass the section start
+        otherwise a data section with no mapping symbol can pick up
+        a text mapping symbol of a preceeding section.  The documentation
+        says section can be NULL, in which case we will seek up all the
+        way to the top.  */
+      if (info->section)
+       section_vma = info->section->vma;
+
+      for (; n >= 0; n--)
+       {
+         addr = bfd_asymbol_value (info->symtab[n]);
+         if (addr < section_vma)
+           break;
 
-           if (get_map_sym_type (info, n, &type))
-             {
-               last_sym = n;
-               found = true;
-               break;
-             }
-         }
-      }
-  }
+         if (get_map_sym_type (info, n, &type))
+           {
+             last_sym = n;
+             found = true;
+             break;
+           }
+       }
+    }
 
   /* If no mapping symbol was found, try looking up without a mapping
      symbol.  This is done by walking up from the current PC to the nearest