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From: "dje at google dot com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug symtab/17591] New: dwarf2read.c:find_slot_in_mapped_hash needs
 to handle "(anonymous namespace)"
Date: Wed, 12 Nov 2014 22:31:00 -0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=17591

            Bug ID: 17591
           Summary: dwarf2read.c:find_slot_in_mapped_hash needs to handle
                    "(anonymous namespace)"
           Product: gdb
           Version: 7.8
            Status: NEW
          Severity: normal
          Priority: P2
         Component: symtab
          Assignee: unassigned at sourceware dot org
          Reporter: dje at google dot com

I was debugging a perf issue and found this in find_slot_in_mapped_hash:

  if (current_language->la_language == language_cplus
      || current_language->la_language == language_java
      || current_language->la_language == language_fortran)
    {
      /* NAME is already canonical.  Drop any qualifiers as .gdb_index does     
         not contain any.  */
      const char *paren = strchr (name, '(');

      if (paren)
        {
          char *dup;

          dup = xmalloc (paren - name + 1);
          memcpy (dup, name, paren - name);
          dup[paren - name] = 0;

          make_cleanup (xfree, dup);
          name = dup;
        }
    }

What if name is "(anonymous namespace)" ?

For the program at hand, this results in symbol table entry 0 which has 1085
entries.

[  0] :
        4 [static, function]
        5 [static, function]
        6 [static, function]
... some global functions
        2737 [static, function]
        2739 [static, function]
        2743 [static, function]


None of the CUs for these entries define anonymous namespace, but since we're
looking up in VAR_DOMAIN the index returns a match and we expand the CU.

While we should fix find_slot_in_mapped_hash, there is a side issue of doing a
general purpose lookup (VAR_DOMAIN) when we have (or should have) enough
knowledge to do a more specific lookup (we're looking for a namespace(/type)
not a function).

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