Add detection of C++14 and C++1z compiler features

[ChangeLog][General Improvements] Qt's buildsystem now detects whether
the compiler supports C++14 and experimental support for C++1z. If the
compiler supports it, then Qt is automatically compiled using that
support.
\
This does not apply to user applications built using qmake: those are
still built with C++11 support only. To enable support for C++14 in your
application, add to your .pro file: CONFIG += c++14 (similarly for
C++1z).

Change-Id: Ib056b47dde3341ef9a52ffff13ef1f5d01c42596
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

18 files changed, 256 insertions, 78 deletions

diff --git a/config.tests/common/c++14/c++14.cpp b/config.tests/common/c++14/c++14.cpp
new file mode 100644
index 0000000000..e17e51831d
--- /dev/null
+++ b/config.tests/common/c++14/c++14.cpp
@@ -0,0 +1,40 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Intel Corporation.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the configuration module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#if __cplusplus > 201103L
+// Compiler claims to support C++14, trust it
+#else
+#  error "__cplusplus must be > 201103L (the value of C++11)"
+#endif
+
+int main(int, char **) { return 0; }
diff --git a/config.tests/common/c++14/c++14.pro b/config.tests/common/c++14/c++14.pro
new file mode 100644
index 0000000000..cbd78ba6fe
--- /dev/null
+++ b/config.tests/common/c++14/c++14.pro
@@ -0,0 +1,3 @@
+SOURCES = c++14.cpp
+CONFIG += c++11 c++14 console
+CONFIG -= qt
diff --git a/config.tests/common/c++1z/c++1z.cpp b/config.tests/common/c++1z/c++1z.cpp
new file mode 100644
index 0000000000..2b61cfec49
--- /dev/null
+++ b/config.tests/common/c++1z/c++1z.cpp
@@ -0,0 +1,40 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Intel Corporation.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the configuration module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#if __cplusplus > 201402L
+// Compiler claims to support experimental C++1z, trust it
+#else
+#  error "__cplusplus must be > 201402L (the value for C++14)"
+#endif
+
+int main(int, char **) { return 0; }
diff --git a/config.tests/common/c++1z/c++1z.pro b/config.tests/common/c++1z/c++1z.pro
new file mode 100644
index 0000000000..3a24946276
--- /dev/null
+++ b/config.tests/common/c++1z/c++1z.pro
@@ -0,0 +1,3 @@
+SOURCES = c++1z.cpp
+CONFIG += c++11 c++14 c++1z console
+CONFIG -= qt
diff --git a/configure b/configure
index 7f65377ac3..b188055143 100755
--- a/configure
+++ b/configure
@@ -769,7 +769,7 @@ CFG_SANITIZE_MEMORY=no
 CFG_SANITIZE_UNDEFINED=no
 CFG_PCRE=auto
 QPA_PLATFORM_GUARD=yes
-CFG_CXX11=auto
+CFG_STDCXX=auto
 CFG_DIRECTWRITE=no
 CFG_WERROR=auto
 CFG_HEADERSCLEAN=auto
@@ -935,6 +935,7 @@ while [ "$#" -gt 0 ]; do
     -sdk| \
     -arch| \
     -host-arch| \
+    -c++std | \
     -mysql_config| \
     -psql_config| \
     -qpa| \
@@ -2234,12 +2235,31 @@ while [ "$#" -gt 0 ]; do
         fi
         ;;
     c++11)
-        if [ "$VAL" = "yes" ] || [ "$VAL" = "no" ]; then
-            CFG_CXX11="$VAL"
+        if [ "$VAL" = "yes" ]; then
+            CFG_STDCXX="c++11"
+        elif [ "$VAL" = "no" ]; then
+            CFG_STDCXX="c++98"
         else
             UNKNOWN_OPT=yes
         fi
         ;;
+    c++std)
+        case "$VAL" in
+            c++98|c++11|c++14|c++1z|auto)
+                CFG_STDCXX="$VAL"
+                ;;
+            98|11|14|1z)
+                CFG_STDCXX="c++$VAL"
+                ;;
+            1y|c++1y)
+                CFG_STDCXX="c++14"
+                ;;
+            *)
+                echo >&2 "Invalid C++ edition: $VAL; valid options are: c++98 c++11 c++14 c++1z auto"
+                ERROR=yes
+                ;;
+        esac
+        ;;
     system-proxies)
         if [ "$VAL" = "yes" ] || [ "$VAL" = "no" ]; then
             CFG_SYSTEM_PROXIES="$VAL"
@@ -2411,8 +2431,8 @@ Configure options:
     -confirm-license ... Automatically acknowledge the license (use with
                          either -opensource or -commercial)
 
-    -no-c++11 .......... Do not compile Qt with C++11 support enabled.
- +  -c++11 ............. Compile Qt with C++11 support enabled.
+    -c++std <edition> .. Compile Qt with C++ standard edition (c++98, c++11, c++14, c++1z)
+                         Default: highest supported
 
  *  -shared ............ Create and use shared Qt libraries.
     -static ............ Create and use static Qt libraries.
@@ -4323,24 +4343,47 @@ if [ "$CFG_SEPARATE_DEBUG_INFO" = "yes" ]; then
     fi
 fi
 
-# Detect C++11 support
-if [ "$CFG_CXX11" != "no" ]; then
-    # Configure detects compiler features based on cross compiler, so we need
-    # to explicitly disable C++11 on Mac to avoid breaking builds where the
-    # host compiler does not support it.
-    if [ "$BUILD_ON_MAC" = "yes" ] && [ "$XPLATFORM_ANDROID" = "yes" ]; then
-        CFG_CXX11="no"
-    elif compileTest common/c++11 "C++11"; then
-        CFG_CXX11="yes"
-    elif [ "$CFG_CXX11" != "auto" ] && [ "$CFG_CONFIGURE_EXIT_ON_ERROR" = "yes" ]; then
-        echo "C++11 support cannot be enabled due to functionality tests!"
-        echo " Turn on verbose messaging (-v) to $0 to see the final report."
-        echo " If you believe this message is in error you may use the continue"
-        echo " switch (-continue) to $0 to continue."
-        exit 101
+# Detect C++11 & up support
+# Configure detects compiler features based on cross compiler, so we need
+# to explicitly disable C++11 on Mac to avoid breaking builds where the
+# host compiler does not support it.
+stdcxx_error=false
+if [ "$BUILD_ON_MAC" = "yes" ] && [ "$XPLATFORM_ANDROID" = "yes" ]; then
+    CFG_STDCXX="c++98"
+elif [ "$CFG_STDCXX" = "c++98" ]; then
+    : # CFG_STDCXX is correct
+elif ! compileTest common/c++11 "C++11"; then
+    if [ "$CFG_STDCXX" != "auto" ]; then
+        stdcxx_error=true
+    else
+        CFG_STDCXX="c++98"
+    fi
+elif [ "$CFG_STDCXX" = "c++11" ]; then
+    : # CFG_STDCXX is correct
+elif ! compileTest common/c++14 "C++14"; then
+    if [ "$CFG_STDCXX" != "auto" ]; then
+        stdcxx_error=true
     else
-        CFG_CXX11="no"
+        CFG_STDCXX="c++11"
     fi
+elif [ "$CFG_STDCXX" = "c++14" ]; then
+    : # CFG_STDCXX is correct
+elif ! compileTest common/c++1z "C++1z"; then
+    if [ "$CFG_STDCXX" != "auto" ]; then
+        stdcxx_error=true
+    else
+        CFG_STDCXX="c++14"
+    fi
+else
+    CFG_STDCXX="c++1z"
+fi
+
+if $stdcxx_error && [ "$CFG_CONFIGURE_EXIT_ON_ERROR" = "yes" ]; then
+    echo "$CFG_STDCXX support cannot be enabled due to functionality tests!"
+    echo " Turn on verbose messaging (-v) to $0 to see the final report."
+    echo " If you believe this message is in error you may use the continue"
+    echo " switch (-continue) to $0 to continue."
+    exit 101
 fi
 
 # Detect which edition of the C++ standard the compiler defaults to
@@ -6086,7 +6129,15 @@ fi
 # ask for all that hasn't been auto-detected or specified in the arguments
 #-------------------------------------------------------------------------------
 
-[ "$CFG_CXX11" = "yes" ] && QT_CONFIG="$QT_CONFIG c++11"
+if [ "$CFG_STDCXX" != "c++98" ]; then
+    QT_CONFIG="$QT_CONFIG c++11"
+    if [ "$CFG_STDCXX" != "c++11" ]; then
+        QT_CONFIG="$QT_CONFIG c++14"
+        if [ "$CFG_STDCXX" != "c++14" ]; then
+            QT_CONFIG="$QT_CONFIG c++1z"
+        fi
+    fi
+fi
 
 if [ "$CFG_SILENT" = "yes" ]; then
     QMAKE_CONFIG="$QMAKE_CONFIG silent"
@@ -7104,7 +7155,7 @@ else
 fi
 unset build_mode release
 echo "  Using sanitizer(s)...... $CFG_SANITIZERS"
-echo "  Using C++11 ............ $CFG_CXX11"
+echo "  Using C++ standard ..... $CFG_STDCXX"
 echo "  Using gold linker....... $CFG_USE_GOLD_LINKER"
 echo "  Using new DTAGS ........ $CFG_ENABLE_NEW_DTAGS"
 echo "  Using PCH .............. $CFG_PRECOMPILE"
diff --git a/mkspecs/common/clang.conf b/mkspecs/common/clang.conf
index ee5fc14458..ee9c1b8371 100644
--- a/mkspecs/common/clang.conf
+++ b/mkspecs/common/clang.conf
@@ -27,9 +27,15 @@ QMAKE_CXXFLAGS_USE_PRECOMPILE    = $$QMAKE_CFLAGS_USE_PRECOMPILE
 QMAKE_CXXFLAGS_LTCG              = $$QMAKE_CFLAGS_LTCG
 QMAKE_CXXFLAGS_DISABLE_LTCG      = $$QMAKE_CFLAGS_DISABLE_LTCG
 QMAKE_CXXFLAGS_CXX11             = -std=c++11
+QMAKE_CXXFLAGS_CXX14             = -std=c++1y
+QMAKE_CXXFLAGS_CXX1Z             = -std=c++1z
 QMAKE_CXXFLAGS_GNUCXX11          = -std=gnu++11
+QMAKE_CXXFLAGS_GNUCXX14          = -std=gnu++1y
+QMAKE_CXXFLAGS_GNUCXX1Z          = -std=gnu++1z
 
 QMAKE_LFLAGS_CXX11      =
+QMAKE_LFLAGS_CXX14      =
+QMAKE_LFLAGS_CXX1Z      =
 QMAKE_LFLAGS_LTCG       = $$QMAKE_CFLAGS_LTCG
 
 # Wrapper tools that understand .o/.a files with LLVM bytecode instead of machine code
diff --git a/mkspecs/common/g++-base.conf b/mkspecs/common/g++-base.conf
index 114a441687..4254551994 100644
--- a/mkspecs/common/g++-base.conf
+++ b/mkspecs/common/g++-base.conf
@@ -28,5 +28,11 @@ QMAKE_CXXFLAGS_PRECOMPILE     = -x c++-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_P
 QMAKE_CXXFLAGS_USE_PRECOMPILE = $$QMAKE_CFLAGS_USE_PRECOMPILE
 
 QMAKE_CXXFLAGS_CXX11    = -std=c++0x
+QMAKE_CXXFLAGS_CXX14    = -std=c++1y
+QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
 QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++0x
+QMAKE_CXXFLAGS_GNUCXX14 = -std=gnu++1y
+QMAKE_CXXFLAGS_GNUCXX1Z = -std=gnu++1z
 QMAKE_LFLAGS_CXX11      =
+QMAKE_LFLAGS_CXX14      =
+QMAKE_LFLAGS_CXX1Z      =
diff --git a/mkspecs/common/qcc-base-qnx.conf b/mkspecs/common/qcc-base-qnx.conf
index a0a88b9605..f7da151a41 100644
--- a/mkspecs/common/qcc-base-qnx.conf
+++ b/mkspecs/common/qcc-base-qnx.conf
@@ -45,6 +45,8 @@ QMAKE_LIBDIR            = $${QNX_DIR}/$${QNX_CPUDIR}/lib $${QNX_DIR}/$${QNX_CPUD
 QMAKE_LFLAGS           += -Wl,-rpath-link,$${QNX_DIR}/$${QNX_CPUDIR}/lib -Wl,-rpath-link,$${QNX_DIR}/$${QNX_CPUDIR}/usr/lib
 
 QMAKE_CXXFLAGS_CXX11    = -Wc,-std=gnu++0x
+QMAKE_CXXFLAGS_CXX14    = -Wc,-std=gnu++1y
+QMAKE_CXXFLAGS_CXX1Z    = -Wc,-std=gnu++1z
 
 QMAKE_LINK_C            = $$QMAKE_CC
 QMAKE_LINK_C_SHLIB      = $$QMAKE_CC
diff --git a/mkspecs/features/c++11.prf b/mkspecs/features/c++11.prf
deleted file mode 100644
index c8a86548ee..0000000000
--- a/mkspecs/features/c++11.prf
+++ /dev/null
@@ -1,9 +0,0 @@
-strict_c++|isEmpty(QMAKE_CXXFLAGS_GNUCXX11) {
-    QMAKE_CXXFLAGS += $$QMAKE_CXXFLAGS_CXX11
-    QMAKE_OBJECTIVE_CFLAGS += $$QMAKE_CXXFLAGS_CXX11
-    QMAKE_LFLAGS += $$QMAKE_LFLAGS_CXX11
-} else {
-    QMAKE_CXXFLAGS += $$QMAKE_CXXFLAGS_GNUCXX11
-    QMAKE_OBJECTIVE_CFLAGS += $$QMAKE_CXXFLAGS_GNUCXX11
-    QMAKE_LFLAGS += $$QMAKE_LFLAGS_GNUCXX11
-}
diff --git a/mkspecs/features/c++14.prf b/mkspecs/features/c++14.prf
deleted file mode 100644
index 076458560d..0000000000
--- a/mkspecs/features/c++14.prf
+++ /dev/null
@@ -1,23 +0,0 @@
-intel_icc {
-    # ICC does not support C++14 yet
-} else: clang {
-    # Clang has supported -std=c++1y since version 3.2
-    greaterThan(QT_CLANG_MAJOR_VERSION, 3)|greaterThan(QT_CLANG_MINOR_VERSION, 1) {
-        QMAKE_CXXFLAGS_CXX11 = -std=c++1y
-        QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++1y
-    }
-    # Unknown how long Apple Clang has supported -std=c++1y, but at least since XCode 5.0
-    greaterThan(QT_APPLE_CLANG_MAJOR_VERSION, 4) {
-        QMAKE_CXXFLAGS_CXX11 = -std=c++1y
-        QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++1y
-    }
-} else: gcc {
-    # GCC has supported -std=c++1y since 4.8
-    greaterThan(QT_GCC_MAJOR_VERSION, 4)|greaterThan(QT_GCC_MINOR_VERSION, 7) {
-        QMAKE_CXXFLAGS_CXX11 = -std=c++1y
-        QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++1y
-    }
-}
-
-# Delegate to c++11.prf
-include(c++11.prf)
diff --git a/mkspecs/features/default_post.prf b/mkspecs/features/default_post.prf
index bcaddc8363..ebe83af25e 100644
--- a/mkspecs/features/default_post.prf
+++ b/mkspecs/features/default_post.prf
@@ -98,6 +98,21 @@ breakpad {
     !isEmpty(QMAKE_STRIP):QMAKE_POST_LINK = $$QMAKE_POST_LINK$$escape_expand(\\n\\t)$$quote($$QMAKE_STRIP $$DEBUGFILENAME)
 }
 
+c++11|c++14|c++1z {
+    c++1z:       cxxstd = CXX1Z
+    else: c++14: cxxstd = CXX14
+    else:        cxxstd = CXX11
+
+    # Check if we should disable the GNU extensions or not
+    !strict_c++:!isEmpty(QMAKE_CXXFLAGS_GNU$$cxxstd): cxxstd = GNU$$cxxstd
+
+    QMAKE_CXXFLAGS += $$eval(QMAKE_CXXFLAGS_$$cxxstd)
+    QMAKE_OBJECTIVE_CFLAGS += $$eval(QMAKE_CXXFLAGS_$$cxxstd)
+    QMAKE_LFLAGS += $$eval(QMAKE_LFLAGS_$$cxxstd)
+
+    unset(cxxstd)
+}
+
 !precompile_header: SOURCES += $$NO_PCH_SOURCES
 
 QMAKE_INCDIR += $$QMAKE_INCDIR_POST
diff --git a/mkspecs/features/mac/sdk.prf b/mkspecs/features/mac/sdk.prf
index e238f8e005..a5643e311d 100644
--- a/mkspecs/features/mac/sdk.prf
+++ b/mkspecs/features/mac/sdk.prf
@@ -72,9 +72,6 @@ isEmpty(QMAKE_MAC_SDK.$${QMAKE_MAC_SDK}.platform_name) {
     # FIXME: Get the version_min_flag out of the platform's 'Native Build System.xcspec'
     version_identifier = $$replace(QMAKE_MAC_PLATFORM_NAME, iphonesimulator, ios-simulator)
 
-    # C++11 support may affect the deployment target
-    c++11: load(c++11)
-
     ios:!host_build: \
         deployment_target = $$QMAKE_IOS_DEPLOYMENT_TARGET
     else: \
diff --git a/mkspecs/features/qt_common.prf b/mkspecs/features/qt_common.prf
index 2ed43e5063..4fb04339f8 100644
--- a/mkspecs/features/qt_common.prf
+++ b/mkspecs/features/qt_common.prf
@@ -13,6 +13,8 @@ QMAKE_DIR_REPLACE_SANE += DESTDIR
 CONFIG -= debug_and_release_target
 
 contains(QT_CONFIG, c++11): CONFIG += c++11 strict_c++
+contains(QT_CONFIG, c++14): CONFIG += c++14
+contains(QT_CONFIG, c++1z): CONFIG += c++1z
 contains(TEMPLATE, .*lib) {
     # module and plugins
     !host_build:contains(QT_CONFIG, reduce_exports): CONFIG += hide_symbols
diff --git a/mkspecs/linux-icc/qmake.conf b/mkspecs/linux-icc/qmake.conf
index ca9e81512e..38f1fe41a7 100644
--- a/mkspecs/linux-icc/qmake.conf
+++ b/mkspecs/linux-icc/qmake.conf
@@ -50,7 +50,11 @@ QMAKE_CXXFLAGS_SPLIT_SECTIONS = $$QMAKE_CFLAGS_SPLIT_SECTIONS
 # Disabling exceptions disabled - workaround for QTBUG-36577
 #QMAKE_CXXFLAGS_EXCEPTIONS_OFF = -fno-exceptions
 QMAKE_CXXFLAGS_CXX11    = -std=c++0x
+QMAKE_CXXFLAGS_CXX14    = -std=c++1y
+QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
 QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++0x
+QMAKE_CXXFLAGS_GNUCXX14 = -std=gnu++1y
+QMAKE_CXXFLAGS_GNUCXX1Z = -std=gnu++1z
 QMAKE_CXXFLAGS_LTCG     = $$QMAKE_CFLAGS_LTCG
 
 QMAKE_INCDIR            =
@@ -73,6 +77,8 @@ QMAKE_LFLAGS_NOUNDEF    = -Wl,-z,defs
 QMAKE_LFLAGS_RPATH      = -Wl,-rpath,
 QMAKE_LFLAGS_RPATHLINK  = -Wl,-rpath-link,
 QMAKE_LFLAGS_CXX11      =
+QMAKE_LFLAGS_CXX14      =
+QMAKE_LFLAGS_CXX1Z      =
 QMAKE_LFLAGS_LTCG       = $$QMAKE_CFLAGS_LTCG
 
 QMAKE_LIBS              =
diff --git a/mkspecs/macx-icc/qmake.conf b/mkspecs/macx-icc/qmake.conf
index c145c2c8f3..ffd95973ce 100644
--- a/mkspecs/macx-icc/qmake.conf
+++ b/mkspecs/macx-icc/qmake.conf
@@ -53,7 +53,11 @@ QMAKE_CXXFLAGS_STATIC_LIB = $$QMAKE_CFLAGS_STATIC_LIB
 QMAKE_CXXFLAGS_YACC     = $$QMAKE_CFLAGS_YACC
 QMAKE_CXXFLAGS_THREAD   = $$QMAKE_CFLAGS_THREAD
 QMAKE_CXXFLAGS_CXX11    = -std=c++11
+QMAKE_CXXFLAGS_CXX14    = -std=c++1y
+QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
 QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++11
+QMAKE_CXXFLAGS_GNUCXX14 = -std=gnu++1y
+QMAKE_CXXFLAGS_GNUCXX1Z = -std=gnu++1z
 QMAKE_CXXFLAGS_SPLIT_SECTIONS = $$QMAKE_CFLAGS_SPLIT_SECTIONS
 QMAKE_CXXFLAGS_LTCG     = $$QMAKE_CFLAGS_LTCG
 
diff --git a/mkspecs/win32-g++/qmake.conf b/mkspecs/win32-g++/qmake.conf
index 019c220de5..388d697b58 100644
--- a/mkspecs/win32-g++/qmake.conf
+++ b/mkspecs/win32-g++/qmake.conf
@@ -56,7 +56,11 @@ QMAKE_CXXFLAGS_RTTI_OFF = -fno-rtti
 QMAKE_CXXFLAGS_EXCEPTIONS_ON = -fexceptions -mthreads
 QMAKE_CXXFLAGS_EXCEPTIONS_OFF = -fno-exceptions
 QMAKE_CXXFLAGS_CXX11    = -std=c++0x
+QMAKE_CXXFLAGS_CXX14    = -std=c++1y
+QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
 QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++0x
+QMAKE_CXXFLAGS_GNUCXX14 = -std=gnu++1y
+QMAKE_CXXFLAGS_GNUCXX1Z = -std=gnu++1z
 QMAKE_CXXFLAGS_SPLIT_SECTIONS = $$QMAKE_CFLAGS_SPLIT_SECTIONS
 
 QMAKE_INCDIR            =
@@ -77,6 +81,8 @@ QMAKE_LFLAGS_CONSOLE    = -Wl,-subsystem,console
 QMAKE_LFLAGS_WINDOWS    = -Wl,-subsystem,windows
 QMAKE_LFLAGS_DLL        = -shared
 QMAKE_LFLAGS_CXX11      =
+QMAKE_LFLAGS_CXX14      =
+QMAKE_LFLAGS_CXX1Z      =
 QMAKE_LFLAGS_GCSECTIONS = -Wl,--gc-sections
 QMAKE_LFLAGS_USE_GOLD   = -fuse-ld=gold
 QMAKE_LINK_OBJECT_MAX   = 10
diff --git a/mkspecs/win32-icc/qmake.conf b/mkspecs/win32-icc/qmake.conf
index 31c87fff26..ff38ada670 100644
--- a/mkspecs/win32-icc/qmake.conf
+++ b/mkspecs/win32-icc/qmake.conf
@@ -46,6 +46,9 @@ QMAKE_CXXFLAGS_RTTI_OFF =
 QMAKE_CXXFLAGS_EXCEPTIONS_ON = -EHsc
 QMAKE_CXXFLAGS_EXCEPTIONS_OFF =
 QMAKE_CXXFLAGS_CXX11    = -Qstd=c++11
+# ICC supports the following but Qt won't compile
+#QMAKE_CXXFLAGS_CXX14    = -Qstd=c++14
+#QMAKE_CXXFLAGS_CXX1Z    = -Qstd=c++1z
 QMAKE_CXXFLAGS_LTCG     = $$QMAKE_CFLAGS_LTCG
 
 QMAKE_INCDIR            =
diff --git a/tools/configure/configureapp.cpp b/tools/configure/configureapp.cpp
index 6a7a217446..ab4e091d6b 100644
--- a/tools/configure/configureapp.cpp
+++ b/tools/configure/configureapp.cpp
@@ -238,7 +238,7 @@ Configure::Configure(int& argc, char** argv)
 
     dictionary[ "COMPILE_EXAMPLES" ] = "yes";
 
-    dictionary[ "C++11" ]           = "auto";
+    dictionary[ "C++STD" ]          = "auto";
 
     dictionary[ "USE_GOLD_LINKER" ] = "no";
 
@@ -464,9 +464,29 @@ void Configure::parseCmdLine()
         }
 
         else if (configCmdLine.at(i) == "-c++11")
-            dictionary[ "C++11" ] = "yes";
+            dictionary[ "C++STD" ] = "c++11";
         else if (configCmdLine.at(i) == "-no-c++11")
-            dictionary[ "C++11" ] = "no";
+            dictionary[ "C++STD" ] = "c++98";
+        else if (configCmdLine.at(i) == "-c++std") {
+            ++i;
+            if (i == argCount)
+                break;
+
+            QString level = configCmdLine.at(i);
+            if (level == "c++98" || level == "c++11" || level == "c++14" || level == "c++1z"
+                    || level == "auto") {
+                dictionary[ "C++STD" ] = level;
+            } else if (level == "98" || level == "11" || level == "14" || level == "1z") {
+                dictionary[ "C++STD" ] = "c++" + level;
+            } else {
+                dictionary[ "DONE" ] = "error";
+                cout << "ERROR: invalid C++ standard " << level
+                     << "; valid options are: c++98 c++11 c++14 c++1z auto" << endl;
+                return;
+            }
+        }
+
+
         else if (configCmdLine.at(i) == "-use-gold-linker")
             dictionary[ "USE_GOLD_LINKER" ] = "yes";
         else if (configCmdLine.at(i) == "-no-use-gold-linker")
@@ -1791,8 +1811,8 @@ bool Configure::displayHelp()
         desc("OPENSOURCE", "opensource", "-opensource",   "Compile and link the Open-Source Edition of Qt.");
         desc("COMMERCIAL", "commercial", "-commercial",   "Compile and link the Commercial Edition of Qt.\n");
 
-        desc("C++11", "yes", "-c++11",                  "Compile Qt with C++11 support enabled.");
-        desc("C++11", "no", "-no-c++11",                "Do not compile Qt with C++11 support enabled.\n");
+        desc(        "-c++std <edition>",               "Compile Qt with C++ standard edition (c++98, c++11, c++14, c++1z)\n"
+                                                        "Default: highest supported. This option is not supported for MSVC.\n");
 
         desc("USE_GOLD_LINKER", "yes", "-use-gold-linker",                  "Link using the GNU gold linker (gcc only).");
         desc("USE_GOLD_LINKER", "no", "-no-use-gold-linker",                "Do not link using the GNU gold linker.\n");
@@ -2117,7 +2137,7 @@ QString Configure::defaultTo(const QString &option)
         return "no";
 
     // keep 'auto' default for msvc, since we can't set the language supported
-    if (option == "C++11"
+    if (option == "C++STD"
         && dictionary["QMAKESPEC"].contains("msvc"))
         return "auto";
 
@@ -2338,9 +2358,16 @@ void Configure::autoDetection()
     // Auto-detect CPU architectures.
     detectArch();
 
-    if (dictionary["C++11"] == "auto") {
-        if (!dictionary["QMAKESPEC"].contains("msvc"))
-            dictionary["C++11"] = tryCompileProject("common/c++11") ? "yes" : "no";
+    if (dictionary["C++STD"] == "auto" && !dictionary["QMAKESPEC"].contains("msvc")) {
+        if (!tryCompileProject("common/c++11")) {
+            dictionary["C++STD"] = "c++98";
+        } else if (!tryCompileProject("common/c++14")) {
+            dictionary["C++STD"] = "c++11";
+        } else if (!tryCompileProject("common/c++1z")) {
+            dictionary["C++STD"] = "c++14";
+        } else {
+            dictionary["C++STD"] = "c++1z";
+        }
     }
 
     if (!dictionary["QMAKESPEC"].contains("msvc")) {
@@ -2544,16 +2571,11 @@ void Configure::autoDetection()
 bool Configure::verifyConfiguration()
 {
     bool prompt = false;
-    if (dictionary["C++11"] != "auto"
+    if (dictionary["C++STD"] != "auto"
             && dictionary["QMAKESPEC"].contains("msvc")) {
-        cout << "WARNING: Qt does not support disabling or enabling any existing C++11 support "
-                "with MSVC compilers.";
-        if (dictionary["C++11"] == "yes")
-            cout << "Therefore -c++11 is ignored." << endl << endl;
-        else
-            cout << "Therefore -no-c++11 is ignored." << endl << endl;
-
-        dictionary["C++11"] = "auto";
+        cout << "WARNING: It is not possible to change the C++ standard edition with MSVC compilers. "
+                "Therefore, the option -c++std " << dictionary["C++STD"] << " was ignored." << endl << endl;
+        dictionary["C++STD"] = "auto";
     }
 
     if (dictionary["STATIC_RUNTIME"] == "yes" && dictionary["SHARED"] == "yes") {
@@ -2695,8 +2717,12 @@ void Configure::generateOutputVars()
         qtConfig += "release";
     }
 
-    if (dictionary[ "C++11" ] == "yes")
+    if (dictionary[ "C++STD" ] == "c++11")
         qtConfig += "c++11";
+    else if (dictionary[ "C++STD" ] == "c++14")
+        qtConfig += "c++11 c++14";
+    else if (dictionary[ "C++STD" ] == "c++1z")
+        qtConfig += "c++11 c++14 c++1z";
     if (!dictionary[ "CFG_STDCXX_DEFAULT" ].isEmpty())
         qmakeVars += "QT_COMPILER_STDCXX = " + dictionary[ "CFG_STDCXX_DEFAULT" ];
 
@@ -3773,7 +3799,7 @@ void Configure::displayConfig()
     }
     if (dictionary[ "BUILD" ] == "release" || dictionary[ "BUILDALL" ] == "yes")
         sout << "Force debug info............" << dictionary[ "FORCEDEBUGINFO" ] << endl;
-    sout << "C++11 support..............." << dictionary[ "C++11" ] << endl;
+    sout << "C++ language standard......." << dictionary[ "C++STD" ] << endl;
     sout << "Link Time Code Generation..." << dictionary[ "LTCG" ] << endl;
     sout << "Accessibility support......." << dictionary[ "ACCESSIBILITY" ] << endl;
     sout << "RTTI support................" << dictionary[ "RTTI" ] << endl;