Allow a toolchain file to specify a generator toolset

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.

1 files changed, 11 insertions, 0 deletions

diff --git a/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake b/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake
index 1ccc1ad..d39f33f 100644
--- a/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake
+++ b/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake
@@ -12,6 +12,17 @@ else()
 endif()
 
 set(RunCMake_GENERATOR_TOOLSET "")
+
 set(RunCMake_TEST_OPTIONS -T "Extra Toolset")
 run_cmake(TwoToolsets)
 unset(RunCMake_TEST_OPTIONS)
+
+if("${RunCMake_GENERATOR}" MATCHES "Visual Studio 1[012]|Xcode" AND NOT XCODE_BELOW_3)
+  set(RunCMake_TEST_OPTIONS -DCMAKE_TOOLCHAIN_FILE=${RunCMake_SOURCE_DIR}/TestToolset-toolchain.cmake)
+  run_cmake(TestToolsetToolchain)
+  unset(RunCMake_TEST_OPTIONS)
+else()
+  set(RunCMake_TEST_OPTIONS -DCMAKE_TOOLCHAIN_FILE=${RunCMake_SOURCE_DIR}/BadToolset-toolchain.cmake)
+  run_cmake(BadToolsetToolchain)
+  unset(RunCMake_TEST_OPTIONS)
+endif()