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, 12 insertions, 3 deletions

diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index dba4f46..bb818eb 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -76,7 +76,8 @@ cmGlobalGenerator::~cmGlobalGenerator()
     }
 }
 
-bool cmGlobalGenerator::SetGeneratorToolset(std::string const& ts)
+bool cmGlobalGenerator::SetGeneratorToolset(std::string const& ts,
+                                            cmMakefile* mf)
 {
   cmOStringStream e;
   e <<
@@ -85,8 +86,7 @@ bool cmGlobalGenerator::SetGeneratorToolset(std::string const& ts)
     "does not support toolset specification, but toolset\n"
     "  " << ts << "\n"
     "was specified.";
-  this->CMakeInstance->IssueMessage(cmake::FATAL_ERROR, e.str(),
-                                    cmListFileBacktrace());
+  mf->IssueMessage(cmake::FATAL_ERROR, e.str());
   return false;
 }
 
@@ -448,6 +448,15 @@ cmGlobalGenerator::EnableLanguage(std::vector<std::string>const& languages,
     mf->ReadListFile(0,fpath.c_str());
     }
 
+  // Tell the generator about the toolset, if any.
+  std::string toolset = mf->GetSafeDefinition("CMAKE_GENERATOR_TOOLSET");
+  if(!toolset.empty() &&
+     !this->SetGeneratorToolset(toolset, mf))
+    {
+    cmSystemTools::SetFatalErrorOccured();
+    return;
+    }
+
   // **** Load the system specific initialization if not yet loaded
   if (!mf->GetDefinition("CMAKE_SYSTEM_SPECIFIC_INITIALIZE_LOADED"))
     {