PR10461: Probe identical functions only once

In C++ especially, a function definition in a header may be compiled
into multiple CUs, but the linker will merge those into a single output
function.  We don't want to place multiple probes on the same function.

The dupe-detection from the alias code (commit 1c6b77e5) already tracks
identical functions within a CU, so I've just lifted this to instead
track function entrypcs at the module level.

* dwflpp.cxx (dwflpp::iterate_over_functions): Remove dupe checks.
* tapsets.cxx (dwarf_query): Add alias_dupes set to the query.
  (dwarf_query::handle_query_module): Reset the dupes for each module.
  (query_dwarf_func): Check that we only probe each entrypc once.

1 files changed, 0 insertions, 10 deletions

diff --git a/dwflpp.cxx b/dwflpp.cxx
index c781ef7a..6a697de7 100644
--- a/dwflpp.cxx
+++ b/dwflpp.cxx
@@ -629,9 +629,6 @@ dwflpp::iterate_over_functions (int (* callback)(Dwarf_Die * func, base_query *
     }
   else if (name_has_wildcard (function))
     {
-      // track addresses we've already seen
-      set<Dwarf_Addr> alias_dupes;
-
       for (it = v->begin(); it != v->end(); it++)
         {
           if (pending_interrupts) return DWARF_CB_ABORT;
@@ -643,13 +640,6 @@ dwflpp::iterate_over_functions (int (* callback)(Dwarf_Die * func, base_query *
                 clog << "function cache " << key << " match " << func_name << " vs "
                      << function << endl;
 
-              // make sure that this function address hasn't
-              // already been matched under an aliased name
-              Dwarf_Addr addr;
-              if (dwarf_entrypc(&die, &addr) == 0 &&
-                  !alias_dupes.insert(addr).second)
-                continue;
-
               rc = (*callback)(& die, q);
               if (rc != DWARF_CB_OK) break;
             }