From 0369d0e7389a5da3d63c2a459662e32d0c47143d Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Sat, 1 Mar 2014 03:33:08 +0000
Subject: [PATCH] [C++11] Replace autoconf --enable-cxx11 with --enable-cxx1y.
 The baseline is now C++11, and we unconditionally add -std=c++11 to the
 flags.

This has the dim potential to break some non-GNU-compatible compiler (in
terms of -std flags) using the makefiles, but those makefiles are
littered with GNU-style compile flags so it would be very surprising to
me for it to actually happen in practice. As always, do let me know if
there is a toolchain you're using where this doesn't work, and I'll be
watching the bots.

llvm-svn: 202569
---
 Makefile.config.in    |  5 +++--
 Makefile.rules        |  6 ++++--
 autoconf/configure.ac | 16 ++++++++--------
 configure             | 22 +++++++++++-----------
 4 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/Makefile.config.in b/Makefile.config.in
index cf6a4f14d77..a272050c75a 100644
--- a/Makefile.config.in
+++ b/Makefile.config.in
@@ -244,8 +244,9 @@ RDYNAMIC := @RDYNAMIC@
 #ENABLE_LIBCPP = 0
 ENABLE_LIBCPP = @ENABLE_LIBCPP@
 
-# When ENABLE_CXX11 is enabled, LLVM uses c++11 mode by default to build.
-ENABLE_CXX11 = @ENABLE_CXX11@
+# When ENABLE_CXX1Y is enabled, LLVM uses c++1y mode by default to build.
+# Otherwise it uses the baseline c++11.
+ENABLE_CXX1Y = @ENABLE_CXX1Y@
 
 # When ENABLE_SPLIT_DWARF is enabled, LLVM uses -gfission to build in debug mode.
 ENABLE_SPLIT_DWARF = @ENABLE_SPLIT_DWARF@
diff --git a/Makefile.rules b/Makefile.rules
index 3f1c2afe73d..62428d1a722 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -319,8 +319,10 @@ ifeq ($(ENABLE_LIBCPP),1)
   LD.Flags +=  -stdlib=libc++
 endif
 
-ifeq ($(ENABLE_CXX11),1)
-  CXX.Flags += -std=c++11
+ifeq ($(ENABLE_CXX1Y),1)
+  CXX.Flags += -std=c++1y
+else
+	CXX.Flags += -std=c++11
 endif
 
 ifeq ($(ENABLE_WERROR),1)
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 018321591c2..72e423928e9 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -589,16 +589,16 @@ bypass these sanity checks.])])
     ;;
 esac
 
-dnl --enable-cxx11 : check whether or not to use -std=c++11 on the command line
-AC_ARG_ENABLE(cxx11,
-              AS_HELP_STRING([--enable-cxx11],
-                             [Use c++11 if available (default is YES)]),,
+dnl --enable-cxx1y : check whether or not to use -std=c++1y on the command line
+AC_ARG_ENABLE(cxx1y,
+              AS_HELP_STRING([--enable-cxx1y],
+                             [Use c++1y if available (default is NO)]),,
                              enableval=default)
 case "$enableval" in
-  yes) AC_SUBST(ENABLE_CXX11,[1]) ;;
-  no)  AC_SUBST(ENABLE_CXX11,[0]) ;;
-  default) AC_SUBST(ENABLE_CXX11,[1]);;
-  *) AC_MSG_ERROR([Invalid setting for --enable-cxx11. Use "yes" or "no"]) ;;
+  yes) AC_SUBST(ENABLE_CXX1Y,[1]) ;;
+  no)  AC_SUBST(ENABLE_CXX1Y,[0]) ;;
+  default) AC_SUBST(ENABLE_CXX1Y,[0]);;
+  *) AC_MSG_ERROR([Invalid setting for --enable-cxx1y. Use "yes" or "no"]) ;;
 esac
 
 dnl --enable-fission : check whether or not to use -gsplit-dwarf on the command
diff --git a/configure b/configure
index deab9899d95..534cd47a007 100755
--- a/configure
+++ b/configure
@@ -684,7 +684,7 @@ BUILD_EXEEXT
 BUILD_CXX
 CVSBUILD
 ENABLE_LIBCPP
-ENABLE_CXX11
+ENABLE_CXX1Y
 ENABLE_SPLIT_DWARF
 ENABLE_CLANG_ARCMT
 ENABLE_CLANG_STATIC_ANALYZER
@@ -1402,7 +1402,7 @@ Optional Features:
   --enable-compiler-version-checks
                           Check the version of the host compiler (default is
                           YES)
-  --enable-cxx11          Use c++11 if available (default is YES)
+  --enable-cxx1y          Use c++1y if available (default is NO)
   --enable-split-dwarf    Use split-dwarf if available (default is NO)
   --enable-clang-arcmt    Enable building of clang ARCMT (default is YES)
   --enable-clang-static-analyzer
@@ -4804,22 +4804,22 @@ echo "$as_me: error: Invalid setting for --enable-compiler-version-checks. Use \
     ;;
 esac
 
-# Check whether --enable-cxx11 was given.
-if test "${enable_cxx11+set}" = set; then
-  enableval=$enable_cxx11;
+# Check whether --enable-cxx1y was given.
+if test "${enable_cxx1y+set}" = set; then
+  enableval=$enable_cxx1y;
 else
   enableval=default
 fi
 
 case "$enableval" in
-  yes) ENABLE_CXX11=1
+  yes) ENABLE_CXX1Y=1
  ;;
-  no)  ENABLE_CXX11=0
+  no)  ENABLE_CXX1Y=0
  ;;
-  default) ENABLE_CXX11=1
+  default) ENABLE_CXX1Y=0
 ;;
-  *) { { echo "$as_me:$LINENO: error: Invalid setting for --enable-cxx11. Use \"yes\" or \"no\"" >&5
-echo "$as_me: error: Invalid setting for --enable-cxx11. Use \"yes\" or \"no\"" >&2;}
+  *) { { echo "$as_me:$LINENO: error: Invalid setting for --enable-cxx1y. Use \"yes\" or \"no\"" >&5
+echo "$as_me: error: Invalid setting for --enable-cxx1y. Use \"yes\" or \"no\"" >&2;}
    { (exit 1); exit 1; }; } ;;
 esac
 
@@ -20165,7 +20165,7 @@ BUILD_EXEEXT!$BUILD_EXEEXT$ac_delim
 BUILD_CXX!$BUILD_CXX$ac_delim
 CVSBUILD!$CVSBUILD$ac_delim
 ENABLE_LIBCPP!$ENABLE_LIBCPP$ac_delim
-ENABLE_CXX11!$ENABLE_CXX11$ac_delim
+ENABLE_CXX1Y!$ENABLE_CXX1Y$ac_delim
 ENABLE_SPLIT_DWARF!$ENABLE_SPLIT_DWARF$ac_delim
 ENABLE_CLANG_ARCMT!$ENABLE_CLANG_ARCMT$ac_delim
 ENABLE_CLANG_STATIC_ANALYZER!$ENABLE_CLANG_STATIC_ANALYZER$ac_delim