From 5a55c91d113bf6b3487fad554f96a905548bdf89 Mon Sep 17 00:00:00 2001
From: cgd <cgd>
Date: Fri, 24 Apr 2009 19:32:34 +0000
Subject: [PATCH] 2009-04-23  Chris Demetriou  <cgd@google.com>

        * configure.ac (HAVE_TR1_UNORDERED_MAP_REHASH): New define.
        * configure: Regenerate.
        * config.in: Regenerate.
        * gold.h: Avoid std::tr1::unordered_map and std::tr1::unordered_set
        if HAVE_TR1_UNORDERED_MAP_REHASH is not defined.
---
 gold/config.in    |  3 +++
 gold/configure    | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 gold/configure.ac | 13 +++++++++++
 gold/gold.h       |  3 ++-
 4 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/gold/config.in b/gold/config.in
index 97af33583c..1ab4ca593d 100644
--- a/gold/config.in
+++ b/gold/config.in
@@ -97,6 +97,9 @@
 /* Define to 1 if you have the <tr1/unordered_map> header file. */
 #undef HAVE_TR1_UNORDERED_MAP
 
+/* Define if ::std::tr1::unordered_map::rehash is usable */
+#undef HAVE_TR1_UNORDERED_MAP_REHASH
+
 /* Define to 1 if you have the <tr1/unordered_set> header file. */
 #undef HAVE_TR1_UNORDERED_SET
 
diff --git a/gold/configure b/gold/configure
index 8cd5153456..45a2c24a8a 100755
--- a/gold/configure
+++ b/gold/configure
@@ -6855,6 +6855,73 @@ fi
 done
 
 
+# Use of ::std::tr1::unordered_map::rehash causes undefined symbols
+# at link time with some versions of GCC.
+echo "$as_me:$LINENO: checking whether ::std::tr1::unordered_map::rehash is usable." >&5
+echo $ECHO_N "checking whether ::std::tr1::unordered_map::rehash is usable.... $ECHO_C" >&6
+if test "${gold_cv_unordered_map_rehash+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+#include <tr1/unordered_map>
+void bar() { ::std::tr1::unordered_map<int, int> x; x.rehash(10); }
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_cxx_werror_flag"
+			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest$ac_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  gold_cv_unordered_map_rehash=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+gold_cv_unordered_map_rehash=no
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: $gold_cv_unordered_map_rehash" >&5
+echo "${ECHO_T}$gold_cv_unordered_map_rehash" >&6
+if test "$gold_cv_unordered_map_rehash" = "yes"; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_TR1_UNORDERED_MAP_REHASH 1
+_ACEOF
+
+fi
+
 # gcc 4.3.0 doesn't recognize the printf attribute on a template
 # function.  Check for that.  This is gcc bug 35546.  This test can
 # probably be removed after the bug has been fixed for a while.
diff --git a/gold/configure.ac b/gold/configure.ac
index e8d576236a..ad04fa6bb6 100644
--- a/gold/configure.ac
+++ b/gold/configure.ac
@@ -325,6 +325,19 @@ AC_CHECK_HEADERS(ext/hash_map ext/hash_set)
 AC_CHECK_HEADERS(byteswap.h)
 AC_CHECK_FUNCS(mallinfo posix_fallocate)
 
+# Use of ::std::tr1::unordered_map::rehash causes undefined symbols
+# at link time with some versions of GCC.
+AC_CACHE_CHECK([whether ::std::tr1::unordered_map::rehash is usable.],
+[gold_cv_unordered_map_rehash],
+[AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <tr1/unordered_map>
+void bar() { ::std::tr1::unordered_map<int, int> x; x.rehash(10); }
+]])], [gold_cv_unordered_map_rehash=yes], [gold_cv_unordered_map_rehash=no])])
+if test "$gold_cv_unordered_map_rehash" = "yes"; then
+  AC_DEFINE(HAVE_TR1_UNORDERED_MAP_REHASH, 1,
+	    [Define if ::std::tr1::unordered_map::rehash is usable])
+fi
+
 # gcc 4.3.0 doesn't recognize the printf attribute on a template
 # function.  Check for that.  This is gcc bug 35546.  This test can
 # probably be removed after the bug has been fixed for a while.
diff --git a/gold/gold.h b/gold/gold.h
index 4c23aa6f6d..efebda8a36 100644
--- a/gold/gold.h
+++ b/gold/gold.h
@@ -65,7 +65,8 @@
 
 // Figure out how to get a hash set and a hash map.
 
-#if defined(HAVE_TR1_UNORDERED_SET) && defined(HAVE_TR1_UNORDERED_MAP)
+#if defined(HAVE_TR1_UNORDERED_SET) && defined(HAVE_TR1_UNORDERED_MAP) \
+    && defined(HAVE_TR1_UNORDERED_MAP_REHASH)
 
 #include <tr1/unordered_set>
 #include <tr1/unordered_map>
-- 
2.11.0