Previously we kept direct link dependencies in OriginalLinkLibraries.
The property exposes the information in the CMake language through the
get/set_property commands. We preserve the OriginalLinkLibraries value
internally to support old APIs like that for CMP0003's OLD behavior, but
the property is now authoritative. This follows up from commit d5cf644a
(Split link information processing into two steps, 2012-11-01).
This will be used later to populate the link interface properties when
exporting targets, and will later allow use of generator expressions
when linking to libraries with target_link_libraries.
Also make targets depend on the (config-specific) union of dependencies.
CMake now allows linking to dependencies or not depending on the config.
However, generated build systems are not all capable of processing
config-specific dependencies, so the targets depend on the union of
dependencies for all configs.
The 'head' is the dependent target to be linked with the current target.
It will be used to evaluate generator expressions with proper handling
of mapped configurations and is used as the source target of properties.
This requires that memoization is done with a key of a pair of target
and config, instead of just config, because now the result also depends
on the target. Removing the memoization entirely is not an option
because it slows cmake down considerably.
Make it a static method instead of an array. It is safer for the
type checking and if we add a new target type we will be warned to add
a case to the switch.
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
Stephen Kelly
Yury G. Kudryashov
Nicolas Despres
Brad King