From 7cf84b13a079740a638fed6b46634bc888bd2622 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim@lrde.epita.fr>
Date: Wed, 7 Jan 2015 10:24:53 +0100
Subject: c++: variants: comparing addresses of typeid.name() is undefined

Instead of storing and comparing pointers to names of types, store
pointers to the typeids, and compares the typeids.
Reported by Thomas Jahns.
<http://lists.gnu.org/archive/html/bug-bison/2014-03/msg00001.html>

* data/variant.hh (yytname_): Replace with...
(yytypeid_): this.
---
 THANKS          |  1 +
 data/variant.hh | 26 +++++++++++++-------------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/THANKS b/THANKS
index 2436f004..908498c7 100644
--- a/THANKS
+++ b/THANKS
@@ -132,6 +132,7 @@ Steve Murphy              murf@parsetree.com
 Sum Wu                    sum@geekhouse.org
 Théophile Ranquet         theophile.ranquet@gmail.com
 Thiru Ramakrishnan        thiru.ramakrishnan@gmail.com
+Thomas Jahns              jahns@dkrz.de
 Tim Josling               tej@melbpc.org.au
 Tim Landscheidt           tim@tim-landscheidt.de
 Tim Van Holder            tim.van.holder@pandora.be
diff --git a/data/variant.hh b/data/variant.hh
index 78c2f945..f918e34c 100644
--- a/data/variant.hh
+++ b/data/variant.hh
@@ -95,13 +95,13 @@ m4_define([b4_variant_define],
 
     /// Empty construction.
     variant ()]b4_parse_assert_if([
-      : yytname_ (YY_NULLPTR)])[
+      : yytypeid_ (YY_NULLPTR)])[
     {}
 
     /// Construct and fill.
     template <typename T>
     variant (const T& t)]b4_parse_assert_if([
-      : yytname_ (typeid (T).name ())])[
+      : yytypeid_ (&typeid (T))])[
     {
       YYASSERT (sizeof (T) <= S);
       new (yyas_<T> ()) T (t);
@@ -110,7 +110,7 @@ m4_define([b4_variant_define],
     /// Destruction, allowed only if empty.
     ~variant ()
     {]b4_parse_assert_if([
-      YYASSERT (!yytname_);
+      YYASSERT (!yytypeid_);
     ])[}
 
     /// Instantiate an empty \a T in here.
@@ -118,9 +118,9 @@ m4_define([b4_variant_define],
     T&
     build ()
     {]b4_parse_assert_if([
-      YYASSERT (!yytname_);
+      YYASSERT (!yytypeid_);
       YYASSERT (sizeof (T) <= S);
-      yytname_ = typeid (T).name ();])[
+      yytypeid_ = & typeid (T);])[
       return *new (yyas_<T> ()) T;
     }
 
@@ -129,9 +129,9 @@ m4_define([b4_variant_define],
     T&
     build (const T& t)
     {]b4_parse_assert_if([
-      YYASSERT (!yytname_);
+      YYASSERT (!yytypeid_);
       YYASSERT (sizeof (T) <= S);
-      yytname_ = typeid (T).name ();])[
+      yytypeid_ = & typeid (T);])[
       return *new (yyas_<T> ()) T (t);
     }
 
@@ -140,7 +140,7 @@ m4_define([b4_variant_define],
     T&
     as ()
     {]b4_parse_assert_if([
-      YYASSERT (yytname_ == typeid (T).name ());
+      YYASSERT (*yytypeid_ == typeid (T));
       YYASSERT (sizeof (T) <= S);])[
       return *yyas_<T> ();
     }
@@ -150,7 +150,7 @@ m4_define([b4_variant_define],
     const T&
     as () const
     {]b4_parse_assert_if([
-      YYASSERT (yytname_ == typeid (T).name ());
+      YYASSERT (*yytypeid_ == typeid (T));
       YYASSERT (sizeof (T) <= S);])[
       return *yyas_<T> ();
     }
@@ -167,8 +167,8 @@ m4_define([b4_variant_define],
     void
     swap (self_type& other)
     {]b4_parse_assert_if([
-      YYASSERT (yytname_);
-      YYASSERT (yytname_ == other.yytname_);])[
+      YYASSERT (yytypeid_);
+      YYASSERT (*yytypeid_ == *other.yytypeid_);])[
       std::swap (as<T> (), other.as<T> ());
     }
 
@@ -198,7 +198,7 @@ m4_define([b4_variant_define],
     destroy ()
     {
       as<T> ().~T ();]b4_parse_assert_if([
-      yytname_ = YY_NULLPTR;])[
+      yytypeid_ = YY_NULLPTR;])[
     }
 
   private:
@@ -233,7 +233,7 @@ m4_define([b4_variant_define],
     } yybuffer_;]b4_parse_assert_if([
 
     /// Whether the content is built: if defined, the name of the stored type.
-    const char *yytname_;])[
+    const std::type_info *yytypeid_;])[
   };
 ]])
 
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