[Cmake-commits] CMake branch, next, updated. v3.0.0-rc6-3458-g0c5cd27
Stephen Kelly
steveire at gmail.com
Sat May 31 06:16:22 EDT 2014
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "CMake".
The branch, next has been updated
via 0c5cd2790876749c4960a6cfb3aadf0d745fa489 (commit)
via 60a981ea8eda7a5af679ca3b2e4d54bc50ad61b3 (commit)
from 58cb98588616331aabcf5b98c29d9a582a7aed61 (commit)
Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.
- Log -----------------------------------------------------------------
http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=0c5cd2790876749c4960a6cfb3aadf0d745fa489
commit 0c5cd2790876749c4960a6cfb3aadf0d745fa489
Merge: 58cb985 60a981e
Author: Stephen Kelly <steveire at gmail.com>
AuthorDate: Sat May 31 06:16:21 2014 -0400
Commit: CMake Topic Stage <kwrobot at kitware.com>
CommitDate: Sat May 31 06:16:21 2014 -0400
Merge topic 'feature-extensions-by-default' into next
60a981ea Features: Enable compiler extensions by default.
http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=60a981ea8eda7a5af679ca3b2e4d54bc50ad61b3
commit 60a981ea8eda7a5af679ca3b2e4d54bc50ad61b3
Author: Stephen Kelly <steveire at gmail.com>
AuthorDate: Fri May 30 15:03:45 2014 +0200
Commit: Stephen Kelly <steveire at gmail.com>
CommitDate: Sat May 31 12:16:12 2014 +0200
Features: Enable compiler extensions by default.
Compilers enable their extensions by default, and disabling them
implicitly can lead to results which are surprising or non-obvious
to debug.
http://public.kitware.com/pipermail/cmake-developers/2014-May/010575.html
http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/10214
https://www.mail-archive.com/cmake-developers@cmake.org/msg10116.html
(Compiler feature extensions by default, 29 May 2014)
diff --git a/Help/command/target_compile_features.rst b/Help/command/target_compile_features.rst
index a6503db..29a8b41 100644
--- a/Help/command/target_compile_features.rst
+++ b/Help/command/target_compile_features.rst
@@ -11,7 +11,7 @@ Specify compiler features required when compiling a given target. If the
feature is not listed in the :variable:`CMAKE_C_COMPILE_FEATURES` variable
or :variable:`CMAKE_CXX_COMPILE_FEATURES` variable,
then an error will be reported by CMake. If the use of the feature requires
-an additional compiler flag, such as ``-std=c++11``, the flag will be added
+an additional compiler flag, such as ``-std=gnu++11``, the flag will be added
automatically.
The ``INTERFACE``, ``PUBLIC`` and ``PRIVATE`` keywords are required to
diff --git a/Help/manual/cmake-compile-features.7.rst b/Help/manual/cmake-compile-features.7.rst
index c014846..d4bbecc 100644
--- a/Help/manual/cmake-compile-features.7.rst
+++ b/Help/manual/cmake-compile-features.7.rst
@@ -47,7 +47,7 @@ be compiled with compiler support for the
In processing the requirement for the ``cxx_constexpr`` feature,
:manual:`cmake(1)` will ensure that the in-use C++ compiler is capable
-of the feature, and will add any necessary flags such as ``-std=c++11``
+of the feature, and will add any necessary flags such as ``-std=gnu++11``
to the compile lines of C++ files in the ``mylib`` target. A
``FATAL_ERROR`` is issued if the compiler is not capable of the
feature.
@@ -59,8 +59,8 @@ for each target.
Such compile flags are added even if the compiler supports the
particular feature without the flag. For example, the GNU compiler
-supports variadic templates (with a warning) even if ``-std=c++98`` is
-used. CMake adds the ``-std=c++11`` flag if ``cxx_variadic_templates``
+supports variadic templates (with a warning) even if ``-std=gnu++98`` is
+used. CMake adds the ``-std=gnu++11`` flag if ``cxx_variadic_templates``
is specified as a requirement.
In the above example, ``mylib`` requires ``cxx_constexpr`` when it
@@ -76,7 +76,7 @@ known feature), that may be specified with the ``PUBLIC`` or
# cxx_constexpr is a usage-requirement
target_compile_features(mylib PUBLIC cxx_constexpr)
- # main.cpp will be compiled with -std=c++11 on GNU for cxx_constexpr.
+ # main.cpp will be compiled with -std=gnu++11 on GNU for cxx_constexpr.
add_executable(myexe main.cpp)
target_link_libraries(myexe mylib)
@@ -84,16 +84,13 @@ Feature requirements are evaluated transitively by consuming the link
implementation. See :manual:`cmake-buildsystem(7)` for more on
transitive behavior of build properties and usage requirements.
-Note that new use of compile feature requirements may expose
-cross-platform bugs in user code. For example, the GNU compiler uses the
-``gnu++98`` language by default as of GCC version 4.8. User code may
-be relying on that by expecting the ``typeof`` GNU extension to work.
-However, if the :command:`target_compile_features` command is used to
-specify the requirement for ``cxx_constexpr``, a ``-std=c++11`` flag may
-be added, and the ``typeof`` extension would no longer be available. The
-solution is to specify that compiler extensions are relied upon by setting
-the :prop_tgt:`CXX_EXTENSIONS` target property to ``ON`` when starting to
-use the :command:`target_compile_features` command.
+Because the :prop_tgt:`CXX_EXTENSIONS` target property is ``ON`` by default,
+CMake uses extended variants of language dialects by default, such as
+``-std=gnu++11`` instead of ``-std=c++11``. That target property may be
+set to ``OFF`` to use the non-extended variant of the dialect flag. Note
+that because most compilers enable extensions by default, this could
+expose cross-platform bugs in user code or in the headers of third-party
+dependencies.
Optional Compile Features
=========================
diff --git a/Help/prop_tgt/CXX_EXTENSIONS.rst b/Help/prop_tgt/CXX_EXTENSIONS.rst
index d7f87a4..67c5cb0 100644
--- a/Help/prop_tgt/CXX_EXTENSIONS.rst
+++ b/Help/prop_tgt/CXX_EXTENSIONS.rst
@@ -5,7 +5,8 @@ Boolean specifying whether compiler specific extensions are requested.
This property specifies whether compiler specific extensions should be
used. For some compilers, this results in adding a flag such
-as ``-std=gnu++11`` instead of ``-std=c++11`` to the compile line.
+as ``-std=gnu++11`` instead of ``-std=c++11`` to the compile line. This
+property is ``ON`` by default.
See the :manual:`cmake-compile-features(7)` manual for information on
compile features.
diff --git a/Help/prop_tgt/CXX_STANDARD.rst b/Help/prop_tgt/CXX_STANDARD.rst
index 8f299bb..b50cdf9 100644
--- a/Help/prop_tgt/CXX_STANDARD.rst
+++ b/Help/prop_tgt/CXX_STANDARD.rst
@@ -5,7 +5,7 @@ The C++ standard whose features are requested to build this target.
This property specifies the C++ standard whose features are requested
to build this target. For some compilers, this results in adding a
-flag such as ``-std=c++11`` to the compile line.
+flag such as ``-std=gnu++11`` to the compile line.
Supported values are ``98`` and ``11``.
@@ -17,9 +17,9 @@ means that using:
set_property(TARGET tgt PROPERTY CXX_STANDARD 11)
-with a compiler which does not support ``-std=c++11`` or an equivalent
+with a compiler which does not support ``-std=gnu++11`` or an equivalent
flag will not result in an error or warning, but will instead add the
-``-std=c++98`` flag if supported. This "decay" behavior may be controlled
+``-std=gnu++98`` flag if supported. This "decay" behavior may be controlled
with the :prop_tgt:`CXX_STANDARD_REQUIRED` target property.
See the :manual:`cmake-compile-features(7)` manual for information on
diff --git a/Help/prop_tgt/C_EXTENSIONS.rst b/Help/prop_tgt/C_EXTENSIONS.rst
index 0772ecc..dc48cc6 100644
--- a/Help/prop_tgt/C_EXTENSIONS.rst
+++ b/Help/prop_tgt/C_EXTENSIONS.rst
@@ -5,7 +5,8 @@ Boolean specifying whether compiler specific extensions are requested.
This property specifies whether compiler specific extensions should be
used. For some compilers, this results in adding a flag such
-as ``-std=gnu11`` instead of ``-std=c11`` to the compile line.
+as ``-std=gnu11`` instead of ``-std=c11`` to the compile line. This
+property is ``ON`` by default.
See the :manual:`cmake-compile-features(7)` manual for information on
compile features.
diff --git a/Help/prop_tgt/C_STANDARD.rst b/Help/prop_tgt/C_STANDARD.rst
index a0c939a..88ca926 100644
--- a/Help/prop_tgt/C_STANDARD.rst
+++ b/Help/prop_tgt/C_STANDARD.rst
@@ -5,7 +5,7 @@ The C standard whose features are requested to build this target.
This property specifies the C standard whose features are requested
to build this target. For some compilers, this results in adding a
-flag such as ``-std=c11`` to the compile line.
+flag such as ``-std=gnu11`` to the compile line.
Supported values are ``90``, ``99`` and ``11``.
@@ -17,9 +17,9 @@ means that using:
set_property(TARGET tgt PROPERTY C_STANDARD 11)
-with a compiler which does not support ``-std=c11`` or an equivalent
+with a compiler which does not support ``-std=gnu11`` or an equivalent
flag will not result in an error or warning, but will instead add the
-``-std=c99`` or ``-std=c90`` flag if supported. This "decay" behavior may
+``-std=gnu99`` or ``-std=gnu90`` flag if supported. This "decay" behavior may
be controlled with the :prop_tgt:`C_STANDARD_REQUIRED` target property.
See the :manual:`cmake-compile-features(7)` manual for information on
diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index f83981e..543d58d 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -2195,8 +2195,16 @@ AddCompilerRequirementFlag(std::string &flags, cmTarget* target,
return;
}
std::string extProp = lang + "_EXTENSIONS";
- bool ext = target->GetPropertyAsBool(extProp);
- std::string type = ext ? "EXTENSION" : "STANDARD";
+ std::string type = "EXTENSION";
+ bool ext = true;
+ if (const char* extPropValue = target->GetProperty(extProp))
+ {
+ if (cmSystemTools::IsOff(extPropValue))
+ {
+ ext = false;
+ type = "STANDARD";
+ }
+ }
if (target->GetPropertyAsBool(lang + "_STANDARD_REQUIRED"))
{
diff --git a/Tests/CxxDialect/CMakeLists.txt b/Tests/CxxDialect/CMakeLists.txt
index 0eb6f8f..8c90339 100644
--- a/Tests/CxxDialect/CMakeLists.txt
+++ b/Tests/CxxDialect/CMakeLists.txt
@@ -4,11 +4,25 @@ project(CxxDialect)
add_executable(use_typeof use_typeof.cxx)
set_property(TARGET use_typeof PROPERTY CXX_STANDARD 98)
-set_property(TARGET use_typeof PROPERTY CXX_EXTENSIONS ON)
add_executable(use_constexpr use_constexpr.cxx)
set_property(TARGET use_constexpr PROPERTY CXX_STANDARD 11)
add_executable(CxxDialect use_constexpr_and_typeof.cxx)
set_property(TARGET CxxDialect PROPERTY CXX_STANDARD 11)
-set_property(TARGET CxxDialect PROPERTY CXX_EXTENSIONS ON)
+
+try_compile(typeof_no_extensions_works
+ "${CMAKE_CURRENT_BINARY_DIR}/use_typeof_test"
+ "${CMAKE_CURRENT_SOURCE_DIR}/use_typeof.cxx"
+ COMPILE_DEFINITIONS
+ CMAKE_FLAGS
+ "-DCMAKE_CXX_STANDARD=98"
+ "-DCMAKE_CXX_EXTENSIONS=FALSE"
+ OUTPUT_VARIABLE OUTPUT
+)
+
+if (typeof_no_extensions_works)
+ message("Use of typeof extension with extensions disabled works, but is expected to fail: ${OUTPUT}")
+else()
+ message("Use of typeof extension with extensions disabled fails, as expected")
+endif()
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX11.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX11.cmake
index 10b251a..f60504f 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX11.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX11.cmake
@@ -1,4 +1,5 @@
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 11)
+set_property(TARGET foo PROPERTY CXX_EXTENSIONS FALSE)
set_property(TARGET foo PROPERTY CXX_STANDARD_REQUIRED TRUE)
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX11Ext.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX11Ext.cmake
index 9e726c8..10b251a 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX11Ext.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX11Ext.cmake
@@ -1,5 +1,4 @@
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 11)
-set_property(TARGET foo PROPERTY CXX_EXTENSIONS TRUE)
set_property(TARGET foo PROPERTY CXX_STANDARD_REQUIRED TRUE)
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX11ExtVariable.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX11ExtVariable.cmake
index 8f6755f..29703db 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX11ExtVariable.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX11ExtVariable.cmake
@@ -2,4 +2,3 @@
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 11)
-set_property(TARGET foo PROPERTY CXX_EXTENSIONS TRUE)
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX11Variable.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX11Variable.cmake
index 29703db..c480997 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX11Variable.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX11Variable.cmake
@@ -2,3 +2,4 @@
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 11)
+set_property(TARGET foo PROPERTY CXX_EXTENSIONS FALSE)
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX98.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX98.cmake
index 4ea595e..fd9fb60 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX98.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX98.cmake
@@ -2,3 +2,4 @@
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 98)
set_property(TARGET foo PROPERTY CXX_STANDARD_REQUIRED TRUE)
+set_property(TARGET foo PROPERTY CXX_EXTENSIONS FALSE)
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX98Ext.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX98Ext.cmake
index fdf4cc7..4ea595e 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX98Ext.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX98Ext.cmake
@@ -1,5 +1,4 @@
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 98)
-set_property(TARGET foo PROPERTY CXX_EXTENSIONS TRUE)
set_property(TARGET foo PROPERTY CXX_STANDARD_REQUIRED TRUE)
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX98ExtVariable.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX98ExtVariable.cmake
index a26a22d..0e3ef8d 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX98ExtVariable.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX98ExtVariable.cmake
@@ -2,4 +2,3 @@
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 98)
-set_property(TARGET foo PROPERTY CXX_EXTENSIONS TRUE)
diff --git a/Tests/RunCMake/CompileFeatures/RequireCXX98Variable.cmake b/Tests/RunCMake/CompileFeatures/RequireCXX98Variable.cmake
index 0e3ef8d..7562264 100644
--- a/Tests/RunCMake/CompileFeatures/RequireCXX98Variable.cmake
+++ b/Tests/RunCMake/CompileFeatures/RequireCXX98Variable.cmake
@@ -2,3 +2,4 @@
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
add_library(foo empty.cpp)
set_property(TARGET foo PROPERTY CXX_STANDARD 98)
+set_property(TARGET foo PROPERTY CXX_EXTENSIONS FALSE)
-----------------------------------------------------------------------
Summary of changes:
hooks/post-receive
--
CMake
More information about the Cmake-commits
mailing list