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Diffstat (limited to 'Help/prop_tgt')
| -rw-r--r-- | Help/prop_tgt/OPTIMIZE_DEPENDENCIES.rst | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/Help/prop_tgt/OPTIMIZE_DEPENDENCIES.rst b/Help/prop_tgt/OPTIMIZE_DEPENDENCIES.rst new file mode 100644 index 0000000..533cf6a --- /dev/null +++ b/Help/prop_tgt/OPTIMIZE_DEPENDENCIES.rst @@ -0,0 +1,38 @@ +OPTIMIZE_DEPENDENCIES +--------------------- + +Activates dependency optimization of static and object libraries. + +When this property is set to true, some dependencies for a static or object +library may be removed at generation time if they are not necessary to build +the library, since static and object libraries don't actually link against +anything. + +If a static or object library has dependency optimization enabled, it first +discards all dependencies. Then, it looks through all of the direct and +indirect dependencies that it initially had, and adds them back if they meet +any of the following criteria: + +* The dependency was added to the library by :command:`add_dependencies`. +* The dependency was added to the library through a source file in the library + generated by a custom command that uses the dependency. +* The dependency has any ``PRE_BUILD``, ``PRE_LINK``, or ``POST_BUILD`` custom + commands associated with it. +* The dependency contains any source files that were generated by a custom + command. +* The dependency contains any languages which produce side effects that are + relevant to the library. Currently, all languages except C, C++, Objective-C, + Objective-C++, assembly, and CUDA are assumed to produce side effects. + However, side effects from one language are assumed not to be relevant to + another (for example, a Fortran library is assumed to not have any side + effects that are relevant for a Swift library.) + +As an example, assume you have a static Fortran library which depends on a +static C library, which in turn depends on a static Fortran library. The +top-level Fortran library has optimization enabled, but the middle C library +does not. If you build the top Fortran library, the bottom Fortran library will +also build, but not the middle C library, since the C library does not have any +side effects that are relevant for the Fortran library. However, if you build +the middle C library, the bottom Fortran library will also build, even though +it does not have any side effects that are relevant to the C library, since the +C library does not have optimization enabled. |