Commit Graph

6 Commits

Author SHA1 Message Date
Brad King d582c23a47 try_compile: Add policy CMP0066 to honor CMAKE_<LANG>_FLAGS_<CONFIG>
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This change was originally made by commit v3.6.0-rc1~160^2 (try_compile: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.
2016-06-29 09:11:02 -04:00
Chuck Atkins 9784af1b50 CMP0065: Restrict the use of CMAKE_SHARED_LIBRARY_LINK_<LANG>_FLAGS
This new policy restricts the addition of the shared library link flags
to executables only when the ENABLE_EXPORTS property is set to True.
2015-09-21 10:12:13 -04:00
Ben Boeckel 594bafe527 cmake: add --trace-expand option
The --trace option is helpful, but sometimes, what you're looking for is
deep under many layers of function calls and figuring out what instance
of the function call you're looking at is tedious to determine (usually
involving patching and message()). Instead, add a --trace-expand option
to trace while expanding commands into what CMake actually sees.
2015-07-23 15:33:10 -04:00
Brad King 882f48e5ba Link libraries by full path even in implicit directories
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.
2015-04-09 11:29:18 -04:00
Brad King 88eb5824da try_compile: Pass linker flags into test project (#14066)
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.
2014-12-03 15:30:22 -05:00
Brad King a41c0a9dcb Do not warn by default when policy CMP0025 or CMP0047 is not set
These policies are triggered by the use of a particular compiler rather
than outdated CMake code in a project.  Avoid warning in every project
that enables a language by not displaying the policy warning by default.
Add variable CMAKE_POLICY_WARNING_CMP<NNNN> to control the warning
explicitly; otherwise enable the warning with --debug-output or --trace.

This breaks with strict policy convention because it does not provide
developers with any warning about the behavior change by default.
Existing projects will continue to build without a warning or change in
behavior.  When a developer changes the minimum required version of
CMake in a project to a sufficiently high value (3.0), the project will
suddenly get the new compiler id and may break, but at least the
breakage comes with a change to the project rather than the version of
CMake used to build it.

Breaking strict policy convention is worthwhile in this case because
very few projects will be affected by the behavior change but every
project would have to see the warning if it were enabled by default.
2014-04-02 14:43:54 -04:00