Projects use `try_compile` to check if they will be able to compile some
particular source code. When a language standard variable like
`CMAKE_CXX_STANDARD` is set, then the project intends to compile source
code using a compiler mode for that standard. Therefore it makes sense
for `try_compile` to use that standard in the test project too.
Unfortunately this was not done when support for the
`CMAKE_CXX_STANDARD` variable was first implemented. Add a policy to
introduce the improved behavior in a compatible way.
Closes: #16456
Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool. Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience. Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.
Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices. It also references version control
history for more precise information. Therefore we no longer need to spell
out the list of Contributors in each source file notice.
Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing". The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.
Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically. Manually fix up shebang lines and trailing
newlines in a few files. Manually update the notices in a few files that the
script does not handle.
In the `try_compile` source file signature we propagate the caller's
value of `CMAKE_<LANG>_FLAGS` into the test project. Extend this to
propagate `CMAKE_<LANG>_FLAGS_<CONFIG>` too instead of always using the
default value in the test project. This will be useful, for example, to
allow the MSVC runtime library to be changed (e.g. `-MDd` => `-MTd`).
However, some projects may currently depend on this not being done,
so we need to activate the behavior using a policy.
This change was originally made by commit v3.6.0-rc1~160^2 (try_compile:
Honor CMAKE_<LANG>_FLAGS_<CONFIG> changes, 2016-04-11) but without the
policy and so had to be reverted during the 3.6 release candidate cycle.
Fixes#16174.
Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
The latter is now the preferred URL for visiting cmake.org with a
browser. Convert using the shell code:
git ls-files -z | xargs -0 sed -i 's|http://www\.cmake|https://cmake|g'
if(TEST TestNameThatExists) will return true if a test with the name
TestNameThatExists has been added with add_test. The syntax is similar
to if(TARGET TargetName). Since use of "TEST" as an argument to if()
could previously be interpreted as a non-keyword argument, add policy
CMP0064 to treat it as a keyword as NEW behavior.
Currently there are an optimal number of policies (64) such that
there are no wasted bits. When another policy is added, the
cmPolicyMap will grow from 40 bytes to 80, and occupy 45. By storing
all in a single bitset, we stay under the cache line size of 64 bytes
until there are 512 policies in a range.
The <LANG>_VISIBILITY_PRESET and VISIBILITY_INLINES_HIDDEN were first
merged in commit v2.8.12~322 (Merge topic 'VISIBILITY_PRESET-property',
2013-06-05) but worked only for shared libraries and executables with
exports. Prior to commit v3.0.0-rc1~581^2 (GenerateExportHeader:
Deprecate add_compiler_export_flags function., 2013-09-02) the
add_compiler_export_flags function was used to add visibility flags to
all targets.
The visibility flags are useful for sources in all target types because
they may be later linked into shared libraries or executables with
exports. Introduce policy CMP0063 to enable them for all target types
while preserving compatibility with existing projects that do not expect
this.
This reverts commit 242c3966 (add_custom_command: Diagnose
MAIN_DEPENDENCY limitation, 2015-03-09) and the follow up commit
b372a99a (UseSWIG: Do not use MAIN_DEPENDENCY on custom commands,
2015-03-26).
I misdiagnosed the underlying issue that prompted creation of policy CMP0057.
The actual issue surfaces when a single custom command's MAIN_DEPENDENCY
is listed in more than one target; this issue will have to be addressed
independently.
When CMP0003 was first introduced we wanted to link all libraries by
full path. However, some projects had problems on platforms where
find_library would find /usr/lib/libfoo.so when the project really
wanted to link to /usr/lib/<arch>/libfoo.so and had been working by
accident because pre-CMP0003 behavior used -lfoo to link.
We first tried to address that in commit v2.6.0~440 (Teach find_library
to avoid returning library paths in system directories, 2008-01-23) by
returning just "foo" for libraries in implicit link directories. This
caused problems for projects expecting find_library to always return a
full path. We ended up using the solution in commit v2.6.0~366 (...
switch library paths found in implicit link directories to use -l,
2008-01-31). However, the special case for libraries in implicit link
directories has also proven problematic and confusing.
Introduce policy CMP0060 to switch to linking all libraries by full path
even if they are in implicit link directories. Explain in the policy
documentation the factors that led to the original approach and now to
this approach.
Add policy CMP0059 to cover this change. The property has been
deprecated since CMake 2.4 anyway.
This will help clean up cmMakefile -- the DefineFlagsOrig member should
not need to exist.
Add policy CMP0058 to avoid generating 'phony' ninja rules for unknown
custom command dependencies. This requires projects to specify their
custom command byproducts explicitly. With this requirement we no
longer have to assume that unknown custom command dependencies are
generated and can instead simply assume they are source files expected
to exist when the build starts. This is particularly important in
in-source builds. It is also helpful for out-of-source builds to allow
Ninja to diagnose missing files before running custom command rules that
depend on them.
Copy CMAKE_EXE_LINKER_FLAGS into the test project generated by
try_compile, just like we already copy CMAKE_<LANG>_FLAGS.
Add CMake Policy CMP0056 to activate this behavior in a compatible way,
but do not warn by default when the policy is not set since it will
affect all try_compile calls.
Extend the RunCMake.try_compile test with a case covering this behavior
for each policy setting.
Allow directories in the source tree or build tree only if the
install tree is a subdirectory of the source tree or build tree,
as appropriate.
Re-use the test files in the RunCMake.include_directories test
to run in multiple scenarios. Bump the required CMake version
in the test to 3.0 to ensure that the new policy warnings are
emitted correctly.
Since commit v2.8.2~105^2~2 (Teach CMake Policies about tweak version
component, 2010-04-23), cmPolicies has known how to handle a policy
introduced in a tweak version. This was done back when we introduced
policies with the current development date version and later updated it
to the release version. Now we always introduce policies using the next
expected release version and explicitly set the policy to test the NEW
behavior.
CMake Policies (or any other features) should never be introduced in a
tweak (bugfix) release, so drop the infrastructure that allows this.
Teach the project() command to set variables
{PROJECT,<PROJECT-NAME>}_VERSION{,_MAJOR,_MINOR,_PATCH,_TWEAK}
holding the project version number and its components. Add project()
command option "VERSION" to specify the version explicitly, and default
to the empty string when it is not given.
Since this clears variables when no VERSION is given, this may change
behavior for existing projects that set the version variables themselves
prior to calling project(). Add policy CMP0048 for compatibility.
Suggested-by: Alex Neundorf <neundorf@kde.org>
Introduce policy CMP0047 to control resetting the id for
compatibility.
De-duplicate content in the QNX platform file by including the GNU
one. QNX is a form of GNU platform.
Do not clear CMAKE_SHARED_LIBRARY_${lang}_FLAGS variables. They
are populated again later by the Compiler/GNU.cmake file anyway.
Modify the CMAKE_CXX_COMPILE_OBJECT variable only when the QCC
compiler id is in use, and the language is CXX. Use the QNX
recommended flag for QCC instead of the gcc compatible -x flag.
Populate new module files to handle system includes and depfiles
when using the QCC compiler.
Remove code which unsets the system include and depfiles related
variables. When a GNU driver is used instead of the QCC one, the
appropriate flags will be used. These variables were previously
cleared for lowest-common-denominator compatibility with both
drivers.
