Imported targets do not themselves build, but we can follow dependencies
through them to find real targets. This allows imported targets to
depend on custom targets that provide the underlying files at build
time.
Strong dependencies (created by add_dependencies) must be honored when
linearizing a strongly-connected component of the target dependency
graph. The initial graph edges have strong/weak labels and can contain
cycles that do not consist exclusively of strong edges. The final graph
never contains cycles so all edges can be strong.
Utility dependencies are "strong" because they must be enforced to
generate a working build. Link dependencies are "weak" because they can
be broken in the case of a static library cycle.
This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.
When an executable target within the project is named in
target_link_libraries for another target, but the executable does not
have the ENABLE_EXPORTS property set, then the executable cannot really
be linked. This is probably a case where the user intends to link to a
third-party library that happens to have the same name as an executable
target in the project (or else will get an error at build time). We
need to avoid making the other target depend on the executable target
incorrectly, since the executable may actually want to link to that
target and this is not a circular depenency.
- Move Tarjan algorithm from cmComputeTargetDepends
into its own class cmComputeComponentGraph
- Use cmComputeComponentGraph to identify the component DAG
of link dependencies in cmComputeLinkDepends
- Emit non-trivial component members more than once but always
in a contiguous group on the link line
- Cycles may be formed among static libraries
- Native build system should not have cycles in target deps
- Create cmComputeTargetDepends to analyze dependencies
- Identify conneced components and use them to fix deps
- Diagnose cycles containing non-STATIC targets
- Add debug mode property GLOBAL_DEPENDS_DEBUG_MODE
- Use results in cmGlobalGenerator as target direct depends
Brad King