8dc3a67c cmMakefile: Out-of-line the directory methods.
0f3c8cfa cmMakefile: Use method abstraction to access directories.
b288a997 cmMakefile: Rename SetStart* directory API to SetCurrent*.
932d53bc cmMakefile: Remove redundant method duplication.
32b8f03a cmMakefile: Port users of GetStart* methods to new names.
54d6a918 cmMakefile: Rename GetCurrent{Output,Binary}Directory.
55d80d0a cmMakefile: Rename GetCurrent{,Source}Directory.
b23cf06f cmake: Remove redundant start directories.
fcf246ac cmMakefile: Populate Home directories on initialize.
8878bea7 cmake: Initialize Home directories on cmake for find-package mode.
044dc815 Use the Home directories from the cmake class where intended.
d67e8f24 cmake: Fix directory used to find the cache
1ea085d1 cmMakefile: Initialize dir definitions early.
f034bb2f Remove redundant calls to MakeStartDirectoriesCurrent.
3a68c323 cmMakefile: Fix wrong parameter names.
Extend the RunSingleCommand signature to capture stdout and stderr
separately. Allow both to be captured to the same std::string
to preserve existing behavior. Update all call sites to do this
so that this refactoring does not introduce functional changes.
6693590f Xcode: Refine quoting rules for Strings
a6331eb8 Xcode: Let PrintComment decide if the comment is non-empty
6e8952c1 Xcode: PrintComment will prepend a whitespace itself before the comment
4bd2544b Xcode: Do not add whitespace after attribute group opening brace
5cb4c838 Xcode: Properly indent PBXFileReference and PBXBuildFile
a723427b Xcode: Remove extra space in PBXProject comment
2fe8bca5 Xcode: Add comment after root object
2e0e205e Xcode: Indent using tabs
7b68c8df Xcode: Sort Xcode objects by Id
this patch series aims to minimize deltas between the CMake Xcode
generator and Xcode itself. It was started by the observation that
if one makes any change to the project within Xcode (e.g. to see
how a variable is called internally) the user cannot diff the CMake
project and the one stored by Xcode afterwards.
Xcode keeps the objects ordered by the object id.
Because cmake stores them into an unordered container
at creation time they must be sorted before writing the
pbxproj file.
I tested this series with Xcode 6.3 and Xcode 3.2. Both show a
reduced diff after this series was applied.
This topic was never tested without some follow-up commits. The
GetCacheEntryValue API returns a pointer to memory freed on return.
It will have to be revised along with the rest of the original topic.
Teach the Xcode generator that ONLY_ACTIVE_ARCH=YES means to use ARCHS,
and that the default of ONLY_ACTIVE_ARCH=NO means to use NATIVE_ARCH and
ignore ARCHS. In the latter case there is no reason to generate ARCHS.
The Ninja build system does not support a in-file verbositiy switch.
Instead teach 'cmake --build' to extract the CMAKE_VERBOSE_MAKEFILE
setting and pass it as an optional '-v' argument to Ninja. This can
serve as a reasonable fallback.
Signed-off-by: Gregor Jasny <gjasny@googlemail.com>
The "cmakexbuild" wrapper is not needed for Xcode 4 and above, and the
path to it may change when CMake moves. Avoid storing a specific path
to a build program in CMakeCache.txt and instead compute the value for
CMAKE_MAKE_PROGRAM on demand. However, if a user does set the value
explicitly then honor it.
This does for Xcode what commit v3.0.0-rc1~260^2~4 (VS: Switch to
internal CMAKE_MAKE_PROGRAM lookup by generators, 2013-11-15) did for
Visual Studio generators.
Extend the change made in commit v3.0.0-rc1~260^2~16 (Teach
GenerateBuildCommand to find its own make program, 2013-11-13) to have
the Xcode generator pick between "xcodebuild" and CMake's own copy of
"cmakexbuild" at build time based on the version of Xcode.
Teach the Xcode generator to compute the location of this tool or the
cmakexbuild wrapper. Add internal APIs to get the locations on demand.
Use the "cmakexbuild" wrapper for Xcode < 4, and "xcodebuild" for modern
Xcode.
The default target in XCode is the first one in the file.
In commit v3.1.0-rc1~286^2 (cmTarget: use a hash_map for cmTargets
typedef, 2014-06-10) the order of the targets stored in cmMakefile was
made non-deterministic instead of lexicographic. Teach the Xcode
generator to do its own sorting to restore a predictable order.
While at it, place ALL_BUILD first (as is done in VS IDE generators)
explicitly in the comparison function so that it is the default target
even if other targets sort earlier lexicographically (e.g. "AAA").
In commit v3.1.0-rc1~687^2~4 (cmTarget: Make the source files depend on
the config, 2014-02-13) an early termination case was added to the Xcode
generator. Fix handling of this case to actually abort all the
generation steps. Otherwise some of the later steps are attempted
without the preconditions normally established by earlier steps,
possibly leading to a crash.
Narrow down the decision if a CFBundle is built to one place.
This is a preparation patch to add another target property
which, if set, will imply BUNDLE. Having only one function
which will have to look at both properties helps to keep code
clean.
Signed-off-by: Gregor Jasny <gjasny@googlemail.com>
The Xcode generator uses Makefiles under a run-script build-phase to
drive custom commands. Fix the generated makefiles for custom commands
with multiple outputs to list all the outputs on the left hand side of
the build rule. This is much simpler and more reliable than the old
multiple-output-pair infrastructure.
A common idiom in CMake-based build systems is to have custom commands
that generate files not listed explicitly as outputs so that these
files do not have to be newer than the inputs. The file modification
times of such "byproducts" are updated only when their content changes.
Then other build rules can depend on the byproducts explicitly so that
their dependents rebuild when the content of the original byproducts
really does change.
This "undeclared byproduct" approach is necessary for Makefile, VS, and
Xcode build tools because if a byproduct were listed as an output of a
rule then the rule would always rerun when the input is newer than the
byproduct but the byproduct may never be updated.
Ninja solves this problem by offering a 'restat' feature to check
whether an output was really modified after running a rule and tracking
the fact that it is up to date separately from its timestamp. However,
Ninja also stats all dependencies up front and will only restat files
that are listed as outputs of rules with the 'restat' option enabled.
Therefore an undeclared byproduct that does not exist at the start of
the build will be considered missing and the build will fail even if
other dependencies would cause the byproduct to be available before its
dependents build.
CMake works around this limitation by adding 'phony' build rules for
custom command dependencies in the build tree that do not have any
explicit specification of what produces them. This is not optimal
because it prevents Ninja from reporting an error when an input to a
rule really is missing. A better approach is to allow projects to
explicitly specify the byproducts of their custom commands so that no
phony rules are needed for them. In order to work with the non-Ninja
generators, the byproducts must be known separately from the outputs.
Add a new "BYPRODUCTS" option to the add_custom_command and
add_custom_target commands to specify byproducts explicitly. Teach the
Ninja generator to specify byproducts as outputs of the custom commands.
In the case of POST_BUILD, PRE_LINK, and PRE_BUILD events on targets
that link, the byproducts must be specified as outputs of the link rule
that runs the commands. Activate 'restat' for such rules so that Ninja
knows it needs to check the byproducts, but not for link rules that have
no byproducts.
Move handling of an empty toolset name into the implementation of the
method. This simplifies the VS 10 implementation of default toolset
selection because it has one code path that is always called.
Xcode requires a separate PBXFileReference for each target source group
that references a source file. Xcode 6 now diagnoses re-use of the same
PBXFileReference from multiple source groups. Add the referencing
target name to our internal map key so we use a per-target reference.
Xcode 6 introduced an 'OTHER_LIBTOOLFLAGS' setting for the "Other
Librarian Flags" of a static library. Now 'OTHER_LDFLAGS' are ignored.
Teach the Xcode generator to choose the correct name for the build
setting based on the type of target and the version of Xcode.
Inspired-by: Jamie Kirkpatrick <jkp@spotify.com>
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.
In commit 84fdc992 (stringapi: Pass configuration names as strings,
2014-02-09) a few code paths for the Xcode 1.5 single-configuration
generator were not updated to use an empty configuration name instead of
a NULL pointer when no configuration is specified in CMAKE_BUILD_TYPE.
Fix them now.
Delay use of CMAKE_GENERATOR_TOOLSET until the CMakeSystem.cmake
file has been configured and loaded during the first project() or
enable_language() command. This gives the toolchain file named by
CMAKE_TOOLCHAIN_FILE a chance to set CMAKE_GENERATOR_TOOLSET. This
point is still early enough to set the generator toolset prior to
the initialization of any languages that might use the toolset.
The cmake::GeneratorToolset member variable remains an indication
of what was specified by the -T option or loaded from the cache.
It does not need to be updated based on the toolchain file setting.
The cmMakefile::TryCompile can still pass cmake::GeneratorToolset
into the inner instance because the try-compiled project will do
platform and language initialization using the CMakeSystem module
configured for the outer project.
Extend the RunCMake.GeneratorToolset test with cases that use a
toolchain file to set CMAKE_GENERATOR_TOOLSET.
Add source file properties to control Xcode file type attributes:
XCODE_EXPLICIT_FILE_TYPE => explicitFileType
XCODE_LAST_KNOWN_FILE_TYPE => lastKnownFileType
Add a RunCMake.XcodeProject test to verify generated project content.
Choose the attribute name and file type and send them through a single
attribute generation code path. Compute the file extension only when
needed. Leave the file type selection logic indented in a block so it
can be made conditional later.
Disallow the use of config-specific source files with
the Visual Studio and Xcode generators. They don't have
any way to represent the condition currently.
Use the same common-config API in cmQtAutoGenerators. While
it accepts config-specific files, it doesn't have to support
multiple configurations yet.
Loop over the configs in cmTargetTraceDependencies
and cmGlobalGenerator::WriteSummary and consume all source
files.
Loop over the configs in cmComputeTargetDepends and compute the
object library dependencies for each config.
Add a ComputeObjectMapping method to compute the object
names. It takes mapping to populate as an out-parameter so
that it can be extended in the future with parameters
relevant to generator expression evaluation.
Remove the supporting cmGeneratorTarget::AddObject method. It is
no longer needed as the container member is populated directly.
The ComputeObjectMapping method is called whenever objects are
requested from the cmGeneratorTarget. Because the Xcode generator
makes no such request, explicitly invoke the method from that
generator so that the logic of checking for bad sources in object
libraries is executed.
In a follow-up, the UseObjectLibraries usage may be replaced by a
true generator expression evaluator for TARGET_OBJECTS. That
will require generators to use cmGeneratorTarget::GetExternalObjects
which is not currently the case for Xcode and VS generators.
Remove use of UseObjectLibraries from Makefile and Ninja generators. It
is not needed now because those generators use GetExternalObjects
which already contains the objects from object libraries.
The VS10 generator calls both the UseObjectLibraries and the GetExternalObjects
methods. Ensure that duplicates are not created by skipping objects
from object libraries in handling of GetExternalObjects.
Similarly, fix VS6, VS7 and Xcode object handling by skipping
external objects from OBJECT_LIBRARY usage as appropriate.
The error message in the BadSourceExpression1 test is now reported
by the generator expression evaluator, so it has different text.
Implement it in terms of the ComputeObjectFilenames virtual method
on the local generators.
Remove the reimplementation from the global generators which are
now all functionally identical.
Until now the cmCustomCommandGenerator was used only to compute the
command lines of a custom command. Generalize it to get the comment,
working directory, dependencies, and outputs of custom commands. Update
use in all generators to support this.
Casts from std::string -> cmStdString were high on the list of things
taking up time. Avoid such implicit casts across function calls by just
using std::string everywhere.
The comment that the symbol name is too long is no longer relevant since
modern debuggers alias the templates anyways and the size is a
non-issue since the underlying methods are generated since it's
inherited.
When using link_directories() and including CMAKE_CFG_INTDIR,
one can end up with duplicate RPATHs in the binary which
install_name_tool cannot fix without corrupting the binary.
Also, the cmake_install.cmake file has been fixed to correctly
handle these generator specific variables.
Images and xib files must have 'lastKnownFileType' attribute to be
displayed correctly. If xib file has attribute 'explicitFileType' it is
displayed as raw xml. If static image has attribute 'explicitFileType'
it is displayed as question mark on storyboard.
Since commit 56831461 (Xcode: Use explicitFileType to mark source types,
2013-04-16) the Xcode generator prefers to use explicitFileType to tell
Xcode about each source file type. This works better than
lastKnownFileType for some file types, but not for "file.storyboard".
If storyboard file has attribute 'explicitFileType' it is displayed
incorrectly (as raw xml). Switch it back to 'lastKnownFileType'.
There is no need to allow EXCLUDE_* properties, because an
INTERFACE_LIBRARY has no direct build output.
IMPORTED_LINK_INTERFACE_LANGUAGES are relevant only to static
libraries.
VERSION is relevant only to the filename of direct build outputs,
which INTERFACE_LIBRARY does not have.
Fix logic introduced by commit eeeeca10 (XCode: Support target folders
on XCode, 2011-02-20) to avoid duplicate subfolders. The problem was
that no slash was appended to the curr_tgt_folder string on the it !=
this->TargetGroup.end() path.
Add a cmGlobalGenerator::SelectMakeProgram method to select a
caller-provided make program, the CMAKE_MAKE_PROGRAM cache entry, or a
generator-provided default. Call it from all implementations of the
GenerateBuildCommand method with the corresponding generator's default,
if any.
All cmGlobalGenerator::GenerateBuildCommand call sites that need to
produce a string now generate "cmake --build" commands. The remaining
call sites immediately pass the result to cmSystemTools::RunSingleCommand.
Avoid the intermediate string and argument parsing by directly producing a
vector of strings. Also drop the ignoreErrors argument because no call
sites remain that use it.
Teach the Xcode generator to set 'lastKnownFileType' to be 'folder' for
file references that are directories. If you set 'explicitFileType' to
'sourcecode', then Xcode cannot browse the directory.
This target type only contains INTERFACE_* properties, so it can be
used as a structural node. The target-specific commands enforce
that they may only be used with the INTERFACE keyword when used
with INTERFACE_LIBRARY targets. The old-style target properties
matching LINK_INTERFACE_LIBRARIES_<CONFIG> are always ignored for
this target type.
The name of the INTERFACE_LIBRARY must match a validity generator
expression. The validity is similar to that of an ALIAS target,
but with the additional restriction that it may not contain
double colons. Double colons will carry the meaning of IMPORTED
or ALIAS targets in CMake 2.8.13.
An ALIAS target may be created for an INTERFACE library.
At this point it can not be exported and does not appear in the
buildsystem and project files are not created for them. That may
be added as a feature in a later commit.
The generators need some changes to handle the INTERFACE_LIBRARY
targets returned by cmComputeLinkInterface::GetItems. The Ninja
generator does not use that API, so it doesn't require changes
related to that.
Xcode 2.1 through 4 supported $(CURRENT_ARCH) in a PBXFileReference
'path' value used in the "Link Binary with Libraries" build phase.
CMake uses this to reference object file locations on link lines to
bring in OBJECT library content. However, Xcode 5 now evaluates the
$(CURRENT_ARCH) reference in this context as "undefined_arch" so the
wrong path is given to the linker. There seems to be no alternative way
to produce an architecture-specific value in a PBXFileReference.
Fortunately Xcode 5 now also handles link dependencies for paths linked
through OTHER_LDFLAGS. For Xcode >= 5, move the OBJECT library object
file references from the link build phase to OTHER_LDFLAGS. We can
still show the object files in the source group listing in either case.
Xcode 5.0 now computes dependencies from files linked through
OTHER_LDFLAGS, so we no longer need the XCODE_DEPEND_HELPER hack to
re-link dependents when targets change.
Replace the cmLocalGenerator GetCompileOptions method with an
AddCompileOptions method since all call sites of the former simply
append the result to a flags string anyway.
Add a "lang" argument to AddCompileOptions and move the
CMAKE_<LANG>_FLAGS_REGEX filter into it. Move the call sites in each
generator to a location that has both the language and configuration
available. In the Makefile generator this also moves the flags from
build.make to flags.make where they belong.
In commit 2bc22bda (Xcode: Add frameworks search paths from link
dependeny closure, 2012-12-07) we made framework search paths from the
link closure conditional on target type, skipping it on STATIC and
OBJECT library targets that do not actually link. However, the
framework search paths also influence the compile lines (-F options) so
we need them for all target types. The Makefile generator already does
this, as did the Xcode generator prior to the above-mentioned commit.
dc1d025 OS X: Add test for rpaths on Mac.
8576b3f OS X: Add support for @rpath in export files.
00d71bd Xcode: Add rpath support in Xcode generator.
94e7fef OS X: Add RPATH support for Mac.
This fixes bug #13797.
The kinds of changes applied in 373faae5 for frameworks are now
applied to CFBundle. The prefix and suffix for CFBundles are
now handled in cmTarget::GetFullNameInternal.
This is initialized by CMAKE_<LANG>_VISIBILITY_PRESET. The target
property is used as the operand to the -fvisibility= compile option
with GNU compilers and clang.
Currently it only adds the contents of the COMPILE_FLAGS target
property, but it can be extended to handle a new COMPILE_OPTIONS
generator expression enabled property.
Make handling of directory separators consistent between
non-bundle and bundle code.
Remove xcode specific flag from cmTarget when getting install_name.
Add (more) consistent convenience functions in cmTarget to get
directories inside of bundles and frameworks to add files to.
This refactor also fixes bug #12263 where frameworks
had the wrong install name when SKIP_BUILD_RPATH.
Also make install_name for frameworks consistent between Makefile
and Xcode generator.
Since commit c519bb2b (XCode: Also qoute [] as needed to set
build-configurations, 2011-04-05) we escape "[]" conditions for
XCODE_ATTRIBUTE_ settings. However, we need to handle the "variant"
condition with a special case to map it only into the settings for the
matching configuration.
Refactor lookup of CMAKE_(EXE|MODULE|SHARED)_LINKER_FLAGS(|_<CONFIG>)
variables to ensure all combinations are handled. Use the helper method
AddConfigVariableFlags to simplify the implementation.
Extend the cmGlobalGenerator::GenerateBuildCommand virtual method
signature with a "projectDir" parameter specifying the top of the
project build tree for which the build command will be generated.
Populate it from call sites in cmGlobalGenerator::Build where a
fully-generated build tree should be available.
The API for retrieving per-config COMPILE_DEFINITIONS has long
existed because of the COMPILE_DEFINITIONS_<CONFIG> style
properties. Ensure that the provided configuration being generated
is also used to evaluate the generator expressions
in cmTarget::GetCompileDefinitions.
Both the generic COMPILE_DEFINITIONS and the config-specific
variant need to be evaluated with the requested configuration. This
has the side-effect that the COMPILE_DEFINITIONS does not need to
be additionally evaluated with no configuration, so the callers can
be cleaned up a bit too.
Generate a unique PBXTargetDependency and PBXContainerItemProxy for
every edge in the dependency graph as required by the Xcode format.
Xcode only accidentally loads project files that re-use the same
PBXTargetDependency for every edge leading to a single target. If one
is removed by hand in the IDE then Xcode may crash due to dangling
references from the others.
Since cmGlobalXCodeGenerator::AddDependTarget is called exactly once for
every edge in the target dependency graph we do not need to keep track
of which edges have been visited to avoid generating duplicates.
The modern cmComputeTargetDepends guarantees there will by no cycles.
Drop the Xcode generator's check which only handled length 1 and 2
cycles anyway.
Since the topic merged to master by commit 34a02846 (Merge topic
'ide-compiler-id', 2012-08-24), these variables are not used by
CMakeDetermine*Compiler.cmake for VS and Xcode generators. Drop the
code that sets them.
Since Xcode doesn't sort the files on its own, let's sort them in our
generator to make navigation easier. Visual Studio, QtCreator, and
kdevelop all display files sorted.
This allows a dependee to inform a target that it should have its
POSITION_INDEPENDENT_CODE property set to ON, or OFF. The value of
the POSITION_INDEPENDENT_CODE property, if set, must be consistent
with any INTERFACE_POSITION_INDEPENDENT_CODE properties on dependees.
Add a test covering the consistency checks on platforms where they run.
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.
The Xcode generator produces FRAMEWORK_SEARCH_PATHS from:
(1) Include directories of the form /path/to/Foo.framework become
-F/path/to so '#include <Foo/H>' can find H in the framework.
(2) Linked frameworks of the form /path/to/Foo.framework become
-F/path/to -framework Foo so the linker can find the framework.
Originally commit 82bb6fae (add framework support to FIND_FILE,
2005-12-27) added these and used the (then current) old-style link
dependency analysis results to get the frameworks. Later a second
setting was added by commit 2ed6191f (add initial xcode framework stuff,
2007-05-08) to transform -F/path/to linker options produced by the old
link line generation into entries appended to FRAMEWORK_SEARCH_PATHS.
Then commit 96fd5909 (Implement linking with paths to library files,
2008-01-22) updated the second setting to directly use the results of
full modern link dependency analysis, but forgot to remove the use of
old-style link results from the original setting location.
The two settings worked together for a while, with the second one
appending to the first. Then commit f33a27ab (Generate native Xcode 3.0
and 3.1 projects, 2009-06-29) changed the internal representation format
produced by the first setting but did not update the second setting to
append to the new representation. As a result, if the first setting
added any paths (usually via the old-style link analysis) then the
second setting containing the modern link analysis results would not be
applied at all.
Fix this by removing use of the old-style link analysis results.
Replace it using the modern link dependencies and remove the second
setting altogether. Now all values for FRAMEWORK_SEARCH_PATHS are
collected in one place so no special append logic is needed.
Pass the name of the requested generator to the generator factory,
which is now responsible to check if it can create a matching
generator for the name. This allows us to add more logic to the
factory in a next step, so that not every possible generator needs
to get registered explicit in cmake::AddDefaultGenerators().
The path must be either absolute or relative to the working directory
from which the makefile will be loaded. In subprojects this is not
relative to the top of the build tree.
Reported-by: David Weese <tre@gmx.de>
Commit 08cb4fa4 (Process generator expressions in the
INCLUDE_DIRECTORIES property, 2012-09-18) contained an incorrect
assumption that CMAKE_BUILD_TYPE was set on the makefile for each
generated configuration in multi-config generators. Fix that by making
the GetIncludeDirectories API depend on the config.
083de7e Process generator expressions in the COMPILE_DEFINITIONS target property.
08cb4fa Process generator expressions in the INCLUDE_DIRECTORIES property.
0ef091d Early return if there is no target.
eb250cd Add a self-reference check for target properties.
7e80747 Add API to check that dependent target properties form a DAG.
239ac84 Add a generator expression for target properties.
e028381 Extend the generator expression language with more logic.
b8e61d6 Refactor GetCompileDefinitions a bit.
2c2b25b Return a std::string from GetCompileDefinitions.
b7e48e0 Add an AppendDefines std::string overload.
9a16087 Convert paths in INCLUDE_DIRECTORIES property to Unix slashes.
4557c8d Don't prepend a path before generator expressions in include_directories.
c6abc41 Add include guard for cmGeneratorExpression.
0ff4e3f Port remaining code to GetCompileDefinitions().
f178d53 Fix indentation in the code blocks generator.
879fd35 Revert "Move GenerateTargetManifest to cmGeneratorTarget."
6674583 Fix compiler warning with initialization order.
5285458 Add convenience for getting a cmGeneratorTarget to use.
c31f3d9 Add a wrapper for accessing config-specific compile-definitions.
d1446ca Append the COMPILE_DEFINITIONS from the Makefile to all targets.
290e92a Move GetIncludeDirectories to cmGeneratorTarget.
f9146f6 Port cmLocalGenerator::GetTargetFlags to cmGeneratorTarget.
9facfd1 Move GetCreateRuleVariable to cmGeneratorTarget.
78bfee3 Make cmLocalGenerator::AddArchitectureFlags take a cmGeneratorTarget.
4f5384e Move GetLinkInformation to cmGeneratorTarget
987e12e Move GenerateTargetManifest to cmGeneratorTarget.
14bf778 Store cmGeneratorTargets with the makefile.
f428ca2 Add more forwarding API to cmGeneratorTarget.
Multiple versions of Xcode may be installed in different locations.
Run "xcode-select --print-path" to detect the active Xcode location
and parse its Contents/version.plist file. Note that the Xcode.app
directory name may vary in developer versions.