Merge topic 'GNU-4.6-compile-features'

770ba876 Help: Add notes for topic 'GNU-4.6-compile-features'
b15c008f Features: Record for GNU 4.6.
f13a2eb1 Features: Adjust the RunCMake test to use more-common features.
1f19ac4d Features: Adjust cxx_variadic_templates unit test for GNU < 4.7.
0798d1e5 Features: Extend the generalized_initializers test for GNU < 4.7.
938bd94e Features: Test __GXX_EXPERIMENTAL_CXX0X__ macro for GNU < 4.7 compatibility.
462c630b Features: Don't test __cplusplus value for CXX98 on GNU.
222ec86f Features: Test an old value of __STDC_VERSION__ for GNU < 4.7 compatibility.
6e909035 Features: Record C/CXX dialect flags for GNU 4.6.
bfc995cc Features: Remove wrong content from else() condition.
1532b921 Features: Make cxx_noexcept available from GNU 4.6.
1f4649e6 Features: Update the default_dialect test for old GNU-like compilers.
a60027a6 Features: Ensure appropriate return value from feature test macros.

8 files changed, 40 insertions, 29 deletions

diff --git a/Modules/Compiler/AppleClang-C.cmake b/Modules/Compiler/AppleClang-C.cmake
index 0665745..16f420f 100644
--- a/Modules/Compiler/AppleClang-C.cmake
+++ b/Modules/Compiler/AppleClang-C.cmake
@@ -19,6 +19,7 @@ macro(cmake_record_c_compile_features)
     record_compiler_features(C "${std_version}" ${list})
   endmacro()
 
+  set(_result 0)
   if (UNIX AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.0)
     _get_appleclang_features(${CMAKE_C11_STANDARD_COMPILE_OPTION} CMAKE_C11_COMPILE_FEATURES)
     if (_result EQUAL 0)
@@ -27,7 +28,5 @@ macro(cmake_record_c_compile_features)
     if (_result EQUAL 0)
       _get_appleclang_features(${CMAKE_C90_STANDARD_COMPILE_OPTION} CMAKE_C90_COMPILE_FEATURES)
     endif()
-  else()
-    set(_result 0)
   endif()
 endmacro()
diff --git a/Modules/Compiler/AppleClang-CXX.cmake b/Modules/Compiler/AppleClang-CXX.cmake
index a508623..978c382 100644
--- a/Modules/Compiler/AppleClang-CXX.cmake
+++ b/Modules/Compiler/AppleClang-CXX.cmake
@@ -26,6 +26,7 @@ macro(cmake_record_cxx_compile_features)
     record_compiler_features(CXX "${std_version}" ${list})
   endmacro()
 
+  set(_result 0)
   if (UNIX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.0)
     set(_result 0)
     if(CMAKE_CXX14_STANDARD_COMPILE_OPTION)
@@ -37,7 +38,5 @@ macro(cmake_record_cxx_compile_features)
     if (_result EQUAL 0)
       _get_appleclang_features(${CMAKE_CXX98_STANDARD_COMPILE_OPTION} CMAKE_CXX98_COMPILE_FEATURES)
     endif()
-  else()
-    set(_result 0)
   endif()
 endmacro()
diff --git a/Modules/Compiler/Clang-C.cmake b/Modules/Compiler/Clang-C.cmake
index ebd5c43..548d0a5 100644
--- a/Modules/Compiler/Clang-C.cmake
+++ b/Modules/Compiler/Clang-C.cmake
@@ -28,6 +28,7 @@ macro(cmake_record_c_compile_features)
     record_compiler_features(C "${std_version}" ${list})
   endmacro()
 
+  set(_result 0)
   if (UNIX AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 3.4)
     _get_clang_features(${CMAKE_C11_STANDARD_COMPILE_OPTION} CMAKE_C11_COMPILE_FEATURES)
     if (_result EQUAL 0)
@@ -36,7 +37,5 @@ macro(cmake_record_c_compile_features)
     if (_result EQUAL 0)
       _get_clang_features(${CMAKE_C90_STANDARD_COMPILE_OPTION} CMAKE_C90_COMPILE_FEATURES)
     endif()
-  else()
-    set(_result 0)
   endif()
 endmacro()
diff --git a/Modules/Compiler/Clang-CXX.cmake b/Modules/Compiler/Clang-CXX.cmake
index 6fe0b56..e07eace 100644
--- a/Modules/Compiler/Clang-CXX.cmake
+++ b/Modules/Compiler/Clang-CXX.cmake
@@ -38,6 +38,7 @@ macro(cmake_record_cxx_compile_features)
     record_compiler_features(CXX "${std_version}" ${list})
   endmacro()
 
+  set(_result 0)
   if (UNIX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.4)
     _get_clang_features(${CMAKE_CXX14_STANDARD_COMPILE_OPTION} CMAKE_CXX14_COMPILE_FEATURES)
     if (_result EQUAL 0)
@@ -46,7 +47,5 @@ macro(cmake_record_cxx_compile_features)
     if (_result EQUAL 0)
       _get_clang_features(${CMAKE_CXX98_STANDARD_COMPILE_OPTION} CMAKE_CXX98_COMPILE_FEATURES)
     endif()
-  else()
-    set(_result 0)
   endif()
 endmacro()
diff --git a/Modules/Compiler/GNU-C-FeatureTests.cmake b/Modules/Compiler/GNU-C-FeatureTests.cmake
index dfaeebf..7e840aa 100644
--- a/Modules/Compiler/GNU-C-FeatureTests.cmake
+++ b/Modules/Compiler/GNU-C-FeatureTests.cmake
@@ -1,7 +1,12 @@
 
-set(_cmake_oldestSupported "(__GNUC__ * 100 + __GNUC_MINOR__) >= 407")
+set(_cmake_oldestSupported "(__GNUC__ * 100 + __GNUC_MINOR__) >= 406")
 
-set(GNU46_C11 "${_cmake_oldestSupported} && defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L")
+# GNU 4.7 correctly sets __STDC_VERSION__ to 201112L, but GNU 4.6 sets it
+# to 201000L.  As the former is strictly greater than the latter, test only
+# for the latter.  If in the future CMake learns about a C feature which was
+# introduced with GNU 4.7, that should test for the correct version, similar
+# to the distinction between __cplusplus and __GXX_EXPERIMENTAL_CXX0X__ tests.
+set(GNU46_C11 "(__GNUC__ * 100 + __GNUC_MINOR__) >= 406 && defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201000L")
 set(_cmake_feature_test_c_static_assert "${GNU46_C11}")
 # Since 4.4 at least:
 set(GNU44_C99 "${_cmake_oldestSupported} && defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L")
diff --git a/Modules/Compiler/GNU-C.cmake b/Modules/Compiler/GNU-C.cmake
index db9089d..d5e747d 100644
--- a/Modules/Compiler/GNU-C.cmake
+++ b/Modules/Compiler/GNU-C.cmake
@@ -1,20 +1,25 @@
 include(Compiler/GNU)
 __compiler_gnu(C)
 
-if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7)
+if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.6)
   set(CMAKE_C90_STANDARD_COMPILE_OPTION "-std=c90")
   set(CMAKE_C90_EXTENSION_COMPILE_OPTION "-std=gnu90")
 
   set(CMAKE_C99_STANDARD_COMPILE_OPTION "-std=c99")
   set(CMAKE_C99_EXTENSION_COMPILE_OPTION "-std=gnu99")
+endif()
 
+if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7)
   set(CMAKE_C11_STANDARD_COMPILE_OPTION "-std=c11")
   set(CMAKE_C11_EXTENSION_COMPILE_OPTION "-std=gnu11")
+elseif (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.6)
+  set(CMAKE_C11_STANDARD_COMPILE_OPTION "-std=c1x")
+  set(CMAKE_C11_EXTENSION_COMPILE_OPTION "-std=gnu1x")
 endif()
 
 if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 5.0)
   set(CMAKE_C_STANDARD_DEFAULT 11)
-else(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7)
+else()
   set(CMAKE_C_STANDARD_DEFAULT 90)
 endif()
 
@@ -23,7 +28,8 @@ macro(cmake_record_c_compile_features)
     record_compiler_features(C "${std_version}" ${list})
   endmacro()
 
-  if (UNIX AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7)
+  set(_result 0)
+  if (UNIX AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.6)
     _get_gcc_features(${CMAKE_C11_STANDARD_COMPILE_OPTION} CMAKE_C11_COMPILE_FEATURES)
     if (_result EQUAL 0)
       _get_gcc_features(${CMAKE_C99_STANDARD_COMPILE_OPTION} CMAKE_C99_COMPILE_FEATURES)
@@ -31,7 +37,5 @@ macro(cmake_record_c_compile_features)
     if (_result EQUAL 0)
       _get_gcc_features(${CMAKE_C90_STANDARD_COMPILE_OPTION} CMAKE_C90_COMPILE_FEATURES)
     endif()
-  else()
-    set(_result 0)
   endif()
 endmacro()
diff --git a/Modules/Compiler/GNU-CXX-FeatureTests.cmake b/Modules/Compiler/GNU-CXX-FeatureTests.cmake
index 6de06dd..267d658 100644
--- a/Modules/Compiler/GNU-CXX-FeatureTests.cmake
+++ b/Modules/Compiler/GNU-CXX-FeatureTests.cmake
@@ -2,7 +2,7 @@
 # Reference: http://gcc.gnu.org/projects/cxx0x.html
 # http://gcc.gnu.org/projects/cxx1y.html
 
-set(_cmake_oldestSupported "(__GNUC__ * 100 + __GNUC_MINOR__) >= 407")
+set(_cmake_oldestSupported "(__GNUC__ * 100 + __GNUC_MINOR__) >= 406")
 
 set(GNU50_CXX14 "(__GNUC__ * 100 + __GNUC_MINOR__) >= 500 && __cplusplus >= 201402L")
 set(_cmake_feature_test_cxx_variable_templates "${GNU50_CXX14}")
@@ -46,7 +46,6 @@ set(_cmake_feature_test_cxx_alias_templates "${GNU47_CXX11}")
 set(_cmake_feature_test_cxx_delegating_constructors "${GNU47_CXX11}")
 set(_cmake_feature_test_cxx_extended_friend_declarations "${GNU47_CXX11}")
 set(_cmake_feature_test_cxx_final "${GNU47_CXX11}")
-set(_cmake_feature_test_cxx_noexcept "${GNU47_CXX11}")
 set(_cmake_feature_test_cxx_nonstatic_member_init "${GNU47_CXX11}")
 set(_cmake_feature_test_cxx_override "${GNU47_CXX11}")
 set(_cmake_feature_test_cxx_user_literals "${GNU47_CXX11}")
@@ -55,22 +54,28 @@ set(_cmake_feature_test_cxx_user_literals "${GNU47_CXX11}")
 # support -std=c++11. Prior to that, support for C++11 features is technically
 # experiemental and possibly incomplete (see for example the note below about
 # cxx_variadic_template_template_parameters)
+# GNU does not define __cplusplus correctly before version 4.7.
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=1773
+# __GXX_EXPERIMENTAL_CXX0X__ is defined in prior versions, but may not be
+# defined in the future.
+set(GNU_CXX0X_DEFINED "(__cplusplus >= 201103L || (defined(__GXX_EXPERIMENTAL_CXX0X__) && __GXX_EXPERIMENTAL_CXX0X__))")
 # TODO: Should be supported by GNU 4.6
-set(GNU46_CXX11 "${_cmake_oldestSupported} && __cplusplus >= 201103L")
+set(GNU46_CXX11 "(__GNUC__ * 100 + __GNUC_MINOR__) >= 406 && ${GNU_CXX0X_DEFINED}")
 set(_cmake_feature_test_cxx_constexpr "${GNU46_CXX11}")
 set(_cmake_feature_test_cxx_defaulted_move_initializers "${GNU46_CXX11}")
 set(_cmake_feature_test_cxx_enum_forward_declarations "${GNU46_CXX11}")
+set(_cmake_feature_test_cxx_noexcept "${GNU46_CXX11}")
 set(_cmake_feature_test_cxx_nullptr "${GNU46_CXX11}")
 set(_cmake_feature_test_cxx_range_for "${GNU46_CXX11}")
 set(_cmake_feature_test_cxx_unrestricted_unions "${GNU46_CXX11}")
 # TODO: Should be supported by GNU 4.5
-set(GNU45_CXX11 "${_cmake_oldestSupported} && __cplusplus >= 201103L")
+set(GNU45_CXX11 "${_cmake_oldestSupported} && ${GNU_CXX0X_DEFINED}")
 set(_cmake_feature_test_cxx_explicit_conversions "${GNU45_CXX11}")
 set(_cmake_feature_test_cxx_lambdas "${GNU45_CXX11}")
 set(_cmake_feature_test_cxx_local_type_template_args "${GNU45_CXX11}")
 set(_cmake_feature_test_cxx_raw_string_literals "${GNU45_CXX11}")
 # TODO: Should be supported by GNU 4.4
-set(GNU44_CXX11 "${_cmake_oldestSupported} && __cplusplus >= 201103L")
+set(GNU44_CXX11 "${_cmake_oldestSupported} && ${GNU_CXX0X_DEFINED}")
 set(_cmake_feature_test_cxx_auto_type "${GNU44_CXX11}")
 set(_cmake_feature_test_cxx_defaulted_functions "${GNU44_CXX11}")
 set(_cmake_feature_test_cxx_deleted_functions "${GNU44_CXX11}")
@@ -90,7 +95,7 @@ set(_cmake_feature_test_cxx_variadic_templates "${GNU44_CXX11}")
 # templates capability in CMake. See
 # http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2555.pdf
 # TODO: Should be supported by GNU 4.3
-set(GNU43_CXX11 "${_cmake_oldestSupported} && __cplusplus >= 201103L")
+set(GNU43_CXX11 "${_cmake_oldestSupported} && ${GNU_CXX0X_DEFINED}")
 set(_cmake_feature_test_cxx_decltype "${GNU43_CXX11}")
 set(_cmake_feature_test_cxx_default_function_template_args "${GNU43_CXX11}")
 set(_cmake_feature_test_cxx_long_long_type "${GNU43_CXX11}")
@@ -98,8 +103,8 @@ set(_cmake_feature_test_cxx_right_angle_brackets "${GNU43_CXX11}")
 set(_cmake_feature_test_cxx_rvalue_references "${GNU43_CXX11}")
 set(_cmake_feature_test_cxx_static_assert "${GNU43_CXX11}")
 # TODO: Should be supported since GNU 3.4?
-set(_cmake_feature_test_cxx_extern_templates "${_cmake_oldestSupported} && __cplusplus >= 201103L")
+set(_cmake_feature_test_cxx_extern_templates "${_cmake_oldestSupported} && ${GNU_CXX0X_DEFINED}")
 # TODO: Should be supported forever?
-set(_cmake_feature_test_cxx_func_identifier "${_cmake_oldestSupported} && __cplusplus >= 201103L")
-set(_cmake_feature_test_cxx_variadic_macros "${_cmake_oldestSupported} && __cplusplus >= 201103L")
-set(_cmake_feature_test_cxx_template_template_parameters "${_cmake_oldestSupported} && __cplusplus >= 199711L")
+set(_cmake_feature_test_cxx_func_identifier "${_cmake_oldestSupported} && ${GNU_CXX0X_DEFINED}")
+set(_cmake_feature_test_cxx_variadic_macros "${_cmake_oldestSupported} && ${GNU_CXX0X_DEFINED}")
+set(_cmake_feature_test_cxx_template_template_parameters "${_cmake_oldestSupported} && __cplusplus")
diff --git a/Modules/Compiler/GNU-CXX.cmake b/Modules/Compiler/GNU-CXX.cmake
index 4a26963..eeada86 100644
--- a/Modules/Compiler/GNU-CXX.cmake
+++ b/Modules/Compiler/GNU-CXX.cmake
@@ -11,7 +11,7 @@ else()
   endif()
 endif()
 
-if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
+if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
   # Supported since 4.3
   set(CMAKE_CXX98_STANDARD_COMPILE_OPTION "-std=c++98")
   set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "-std=gnu++98")
@@ -20,7 +20,10 @@ endif()
 if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
   set(CMAKE_CXX11_STANDARD_COMPILE_OPTION "-std=c++11")
   set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-std=gnu++11")
+elseif (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
   # 4.3 supports 0x variants
+  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION "-std=c++0x")
+  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-std=gnu++0x")
 endif()
 
 if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9)
@@ -42,14 +45,12 @@ macro(cmake_record_cxx_compile_features)
   if (UNIX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
     _get_gcc_features(${CMAKE_CXX14_STANDARD_COMPILE_OPTION} CMAKE_CXX14_COMPILE_FEATURES)
   endif()
-  if (UNIX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
+  if (UNIX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.6)
     if (_result EQUAL 0)
       _get_gcc_features(${CMAKE_CXX11_STANDARD_COMPILE_OPTION} CMAKE_CXX11_COMPILE_FEATURES)
     endif()
     if (_result EQUAL 0)
       _get_gcc_features(${CMAKE_CXX98_STANDARD_COMPILE_OPTION} CMAKE_CXX98_COMPILE_FEATURES)
     endif()
-  else()
-    set(_result 0)
   endif()
 endmacro()