[PATCH] Don't memcpy C++ structures.

[Akim Demaille]

        * data/lalr1-fusion.cc (b4_symbol_variant): Adjust additional
        arguments.
        (variant::build): New overload for
        copy-construction-that-destroys.
        (variant::swap): New.
        (parser::yypush_): Use it in variant mode.
---
 ChangeLog            |   10 ++++++++++
 data/lalr1-fusion.cc |   29 +++++++++++++++++++++++++----
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ea2c3d6..ba6b25f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
 2008-11-04  Akim Demaille  <address@hidden>
 
+       Don't memcpy C++ structures.
+       * data/lalr1-fusion.cc (b4_symbol_variant): Adjust additional
+       arguments.
+       (variant::build): New overload for
+       copy-construction-that-destroys.
+       (variant::swap): New.
+       (parser::yypush_): Use it in variant mode.
+
+2008-11-04  Akim Demaille  <address@hidden>
+
        Better defaults for bench.pl.
        * etc/bench.pl.in ($verbose, $cflags, $iterations): Change the
        default values.
diff --git a/data/lalr1-fusion.cc b/data/lalr1-fusion.cc
index e3cafff..f2659fb 100644
--- a/data/lalr1-fusion.cc
+++ b/data/lalr1-fusion.cc
@@ -85,13 +85,13 @@ m4_define([b4_symbol_action_],
 ])])
 
 
-# b4_symbol_variant(YYTYPE, YYVAL, ACTION)
-# ----------------------------------------
+# b4_symbol_variant(YYTYPE, YYVAL, ACTION, [ARGS])
+# ------------------------------------------------
 # Run some ACTION ("build", or "destroy") on YYVAL of symbol type
 # YYTYPE.
 m4_define([b4_symbol_variant],
 [m4_pushdef([b4_dollar_dollar],
-            [$2.$3<$][3>()])dnl
+            [$2.$3<$][3>(m4_shift3($@))])dnl
   switch ($1)
     {
 m4_map([b4_symbol_action_], m4_defn([b4_type_names]))
@@ -202,6 +202,24 @@ dnl FIXME: This is wrong, we want computed header guards.
       return reinterpret_cast<const T&>(buffer);
     }
 
+    /// Swap the content with \a other.
+    template <typename T>
+    inline void
+    swap(variant<S>& other)
+    {
+      std::swap(as<T>(), other.as<T>());
+    }
+
+    /// Assign the content of \a other to this.
+    /// Destroys \a other.
+    template <typename T>
+    inline void
+    build(variant<S>& other)
+    {
+      build<T>();
+      swap<T>(other);
+    }
+
     /// Destroy the stored \a T.
     template <typename T>
     inline void
@@ -683,7 +701,10 @@ do {                                       \
   ]b4_parser_class_name[::yypush_ (state_type s,
                            semantic_type& v, const location_type& l)
   {
-    yystack_.push (data_type (s, v, l));
+]b4_variant_if(
+[[    yystack_.push (data_type (s, semantic_type(), l));
+    ]b4_symbol_variant([[yystos_[s]]], [[yystack_[0].value]], [build], [v])],
+[    yystack_.push (data_type (s, v, l));])[
   }
 
   void
-- 
1.6.0.2.588.g3102