dwarflint: detect duplicate attributes in .debug_abbrev

diff --git a/dwarflint/check_debug_abbrev.cc b/dwarflint/check_debug_abbrev.cc
index 03e3726dc0e76508cc50206e162817456d51c879..0c0b3558dc10c8f06cc049106eb8e7fd800e7e35 100644 (file)
--- a/dwarflint/check_debug_abbrev.cc
+++ b/dwarflint/check_debug_abbrev.cc
@@ -295,18 +295,20 @@ namespace
        cur->has_children = has_children == DW_CHILDREN_yes;
 
        bool null_attrib;
-       uint64_t sibling_attr = 0;
        bool low_pc = false;
        bool high_pc = false;
        bool ranges = false;
+       std::map<unsigned, uint64_t> seen;
        do
          {
            uint64_t attr_off = read_ctx_get_offset (&ctx);
            uint64_t attrib_name, attrib_form;
            if (first_attr_off == 0)
              first_attr_off = attr_off;
+
            /* Shift to match elfutils reporting.  */
-           where_reset_3 (&where, attr_off - first_attr_off);
+           attr_off -= first_attr_off;
+           where_reset_3 (&where, attr_off);
 
            /* Load attribute name and form.  */
            if (!checked_read_uleb128 (&ctx, &attrib_name, &where,
@@ -337,6 +339,19 @@ namespace
                      << "invalid form " << pri::hex (attrib_form)
                      << '.' << std::endl;
                    throw check_base::failed ();
+               std::pair<std::map<unsigned, uint64_t>::iterator, bool> inserted
+                 = seen.insert (std::make_pair (attrib_name, attr_off));
+               if (!inserted.second)
+                 {
+                   wr_error (where)
+                     << "duplicate attribute " << pri::attr (attrib_name)
+                     << " (first was at " << pri::hex (inserted.first->second)
+                     << ")." << std::endl;
+                   // I think we may allow such files for high-level
+                   // consumption, so don't fail the check...
+                   if (attrib_name == DW_AT_sibling)
+                     // ... unless it's DW_AT_sibling.
+                     failed = true;
                  }
              }
 
@@ -347,27 +362,15 @@ namespace
 
            /* We do structural checking of sibling attribute, so make
               sure our assumptions in actual DIE-loading code are
-              right.  We expect at most one DW_AT_sibling attribute,
-              with form from reference class, but only CU-local, not
-              DW_FORM_ref_addr.  */
+              right.  We expect form from reference class, but only
+              CU-local, not DW_FORM_ref_addr.  */
            if (attrib_name == DW_AT_sibling)
              {
-               if (sibling_attr != 0)
-                 wr_error (where)
-                   << "another DW_AT_sibling attribute in one abbreviation "
-                   << "(first was " << pri::hex (sibling_attr) << ")."
+               if (!cur->has_children)
+                 wr_message (where,
+                             cat (mc_die_rel, mc_acc_bloat, mc_impact_1))
+                   << "excessive DW_AT_sibling attribute at childless abbrev."
                    << std::endl;
-               else
-                 {
-                   assert (attr_off > 0);
-                   sibling_attr = attr_off;
-
-                   if (!cur->has_children)
-                     wr_message (where,
-                                 cat (mc_die_rel, mc_acc_bloat, mc_impact_1))
-                       << "excessive DW_AT_sibling attribute at childless abbrev."
-                       << std::endl;
-                 }
 
                switch (check_sibling_form (ver, attrib_form))
                  {
@@ -383,6 +386,7 @@ namespace
                      << pri::form (attrib_form) << '.' << std::endl;
                  };
              }
+
            /* Similar for DW_AT_location and friends.  */
            else if (is_location_attrib (attrib_name))
              {
@@ -390,6 +394,7 @@ namespace
                  complain_invalid_form (where, attrib_name, attrib_form,
                                         "location attribute");
              }
+
            /* Similar for DW_AT_ranges.  */
            else if (attrib_name == DW_AT_ranges
                     || attrib_name == DW_AT_stmt_list)
@@ -402,6 +407,7 @@ namespace
                if (attrib_name == DW_AT_ranges)
                  ranges = true;
              }
+
            /* Similar for DW_AT_{low,high}_pc, plus also make sure we
               don't see high_pc without low_pc.  */
            else if (attrib_name == DW_AT_low_pc