PR10572: Allow duplicate function names in a CU

We can't assume that a given function name will only appear once in a
CU.  In C++, two functions may have the same name in different classes
or namespaces, or even in the same scope with overloaded parameters.
Even in C, the compiler may generate multiple copies of a single
function with different optimizations.

We now use a multimap for function names, so we shouldn't miss any.

* dwflpp.h (cu_type_cache_t, mod_cu_type_cache_t): New typedef to keep a
  normal map for the global_alias_cache.
  (cu_function_cache_t): Use a multimap for function names.
* dwflpp.cxx (dwflpp::iterate_over_functions): Walk over the range of
  exactly-matching functions.
* tapsets.cxx (query_dwarf_func): Don't abort after seeing an exact
  match -- there could be more to come.

1 files changed, 17 insertions, 13 deletions

diff --git a/dwflpp.cxx b/dwflpp.cxx
index 3c6a106d..d55852ee 100644
--- a/dwflpp.cxx
+++ b/dwflpp.cxx
@@ -106,7 +106,7 @@ dwflpp::~dwflpp()
        it != cu_inl_function_cache.end(); ++it)
     delete it->second;
 
-  for (mod_cu_function_cache_t::iterator it = global_alias_cache.begin();
+  for (mod_cu_type_cache_t::iterator it = global_alias_cache.begin();
        it != global_alias_cache.end(); ++it)
     delete it->second;
 
@@ -594,7 +594,7 @@ dwflpp::iterate_over_inline_instances (int (* callback)(Dwarf_Die * die, void *
 int
 dwflpp::global_alias_caching_callback(Dwarf_Die *die, void *arg)
 {
-  cu_function_cache_t *cache = static_cast<cu_function_cache_t*>(arg);
+  cu_type_cache_t *cache = static_cast<cu_type_cache_t*>(arg);
   const char *name = dwarf_diename(die);
 
   if (!name)
@@ -616,10 +616,10 @@ dwflpp::declaration_resolve(const char *name)
   if (!name)
     return NULL;
 
-  cu_function_cache_t *v = global_alias_cache[cu->addr];
+  cu_type_cache_t *v = global_alias_cache[cu->addr];
   if (v == 0) // need to build the cache, just once per encountered module/cu
     {
-      v = new cu_function_cache_t;
+      v = new cu_type_cache_t;
       global_alias_cache[cu->addr] = v;
       iterate_over_globals(global_alias_caching_callback, v);
       if (sess.verbose > 4)
@@ -650,8 +650,7 @@ dwflpp::cu_function_caching_callback (Dwarf_Die* func, void *arg)
   if (!name)
     return DWARF_CB_OK;
 
-  string function_name = name;
-  (*v)[function_name] = * func;
+  v->insert(make_pair(string(name), *func));
   return DWARF_CB_OK;
 }
 
@@ -677,14 +676,19 @@ dwflpp::iterate_over_functions (int (* callback)(Dwarf_Die * func, base_query *
       mod_info->update_symtab(v);
     }
 
-  cu_function_cache_t::iterator it = v->find(function);
-  if (it != v->end())
+  cu_function_cache_t::iterator it;
+  cu_function_cache_range_t range = v->equal_range(function);
+  if (range.first != range.second)
     {
-      Dwarf_Die& die = it->second;
-      if (sess.verbose > 4)
-        clog << "function cache " << module_name << ":" << cu_name()
-             << " hit " << function << endl;
-      return (*callback)(& die, q);
+      for (it = range.first; it != range.second; ++it)
+        {
+          Dwarf_Die& die = it->second;
+          if (sess.verbose > 4)
+            clog << "function cache " << module_name << ":" << cu_name()
+              << " hit " << function << endl;
+          rc = (*callback)(& die, q);
+          if (rc != DWARF_CB_OK) break;
+        }
     }
   else if (name_has_wildcard (function))
     {