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.
a9c9b66c cmTarget: use a hash_map for cmTargets typedef
bcb6dbc1 cmTarget: help the optimizer a bit
679f3dee cmTarget: use hash_set for sets of strings
23d6520d cmTarget: Allow caching of empty genex expansions
cd54f1db cmTarget: Only copy GenEx expansions when necessary
b75fc0e1 cmTarget: Don't set properties on custom targets
66076915 cmTarget: Use static strings for special property names
cebefa71 cmTarget: Sort special property checks
97ce676e cmTarget: Fast path for regular properties
4cfa918a cmTarget: Factor out common code
85242b7d cmTarget: Use else/if trees rather than an if tree
Replace isLinkDependentProperty with a CompatibleInterfaces structure
that records all the compatible interface properties in a set for each
type. This avoids repeatedly traversing the link implementation closure
and asking every target for its compatible interface properties.
Split the library lists out of LinkImplementation and LinkInterface into
LinkImplementationLibraries and LinkInterfaceLibraries parent classes,
respectively. Return these from GetLinkImplementationLibraries and
GetLinkInterfaceLibraries, respectively, so that callers cannot access
parts of the structures that have not been populated.
The old link dependency analysis is now needed only for the VS 6
generator code delimited by CM_USE_OLD_VS6 to support project-provided
project templates. Rename the related cmTarget members to be "ForVS6".
Implementation of CMP0027 OLD behavior needs to know whether each entry
in LinkImplementation::Libraries came from a generator expression or
not. Add a FromGenex member to cmLinkImplItem to record this.
Create a cmLinkImplItem class derived from cmLinkItem so more
information can be added to link implementation entries than link
interface entries. Convert the LinkImplementation Libraries member to
hold it. Update client sites accordingly.
Add a 'usage_requirements_only' parameter to GetLinkInterfaceLibraries
and supporting internal APIs to pass through to ExpandLinkItems so it
knows whether to use SetTransitivePropertiesOnly while evaluating
generator expressions.
Add a 'usage_requirements_only' parameter to ExpandLinkItems so that it
knows whether to use SetTransitivePropertiesOnly while evaluating
generator expressions. Update existing call sites to pass 'false' since
they are for linking and not usage requirements.
Instead of storing just the string names in these structures, lookup any
target associated with each item and store its cmTarget pointer. Use
the cmLinkItem class to hold the name and pointer together. Update
client sites to use the pre-stored lookup result instead of looking up
the target name again.
Create a cmTarget::LookupLinkItems helper method to handle the lookup.
Since lookups are now moving from cmComputeLinkDepends::AddLinkEntries
to cmTarget::LookupLinkItems, move use of CheckCMP0004 to the latter.
This drops use of CheckCMP0004 from entries added for _LIB_DEPENDS
variables by cmComputeLinkDepends::AddVarLinkEntries, but I do not
think that use was intentional originally anyway.
Add a method like GetUtilities but that provides the target names
already looked up and resolved to cmTarget pointers internally. Update
call site in cmComputeTargetDepends::AddTargetDepend to use the
already-found target instead of looking it up again.
Many items named in target_link_libraries calls are targets, but not
all. Create a cmLinkItem type that acts like std::string so it can name
an item but also has a pointer to a cmTarget that is the result of
looking up the item name in the referencing target's scope. This will
be useful to avoid duplicate lookup operations later.
Move generator expression evaluation for imported library lists out of
GetImportInfo and into a new GetImportLinkInterface helper. This avoids
duplicating the computation and storage of all imported target info just
because some of it is parameterized on the 'head' target.
Many of the 'head' arguments added by commit v2.8.11~289^2~1 (Make
linking APIs aware of 'head' target, 2013-01-04) turned out not to be
needed. The "link implementation" of a target never needs to be
computed with anything but itself as the 'head' target (except for
CMP0022 OLD behavior because then it is the link interface).
Remove the unused 'head' target paths. Add "internal" versions of
cmTarget::GetDirectLinkLibraries and GetLinkImplementationLibraries
to support the CMP0022 OLD behavior without otherwise exposing the
'head' target option of these methods.
Create an ExpandLinkItems method to handle evaluation of generator
expressions in a library list and expansion of the ;-list into a vector.
Replace some duplicate copies of the implementation with calls to the
new helper.
Allow setting build properties based on the features available
for a target. The availability of features is determined at
generate-time by evaluating the link implementation.
Ensure that the <LANG>_STANDARD determined while evaluating
COMPILE_FEATURES in the link implementation is not lower than that
provided by the INTERFACE of the link implementation. This is
similar to handling of transitive properties such as
POSITION_INDEPENDENT_CODE.
These policies should be checked at the call site that tries to access
the LOCATION or SOURCES property, not the directory scope containing the
target. Thread the caller context through cmTarget::GetProperty to use
for checking the policy setting and emitting a diagnostic with proper
backtrace.
Extend the RunCMake.CMP0026 and RunCMake.CMP0051 tests with
cross-directory cases.
Stephen Kelly
Brad King
Gregor Jasny
Ben Boeckel