Features: Add COMPILE_FEATURES generator expression.

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.

1 files changed, 17 insertions, 0 deletions

diff --git a/Source/cmGeneratorExpression.cxx b/Source/cmGeneratorExpression.cxx
index d09e950..d53bdd7 100644
--- a/Source/cmGeneratorExpression.cxx
+++ b/Source/cmGeneratorExpression.cxx
@@ -110,6 +110,9 @@ const char *cmCompiledGeneratorExpression::Evaluate(
       break;
       }
     }
+
+  this->MaxLanguageStandard = context.MaxLanguageStandard;
+
   if (!context.HadError)
     {
     this->HadContextSensitiveCondition = context.HadContextSensitiveCondition;
@@ -465,3 +468,17 @@ bool cmGeneratorExpression::IsValidTargetName(const std::string &input)
 
   return targetNameValidator.find(input.c_str());
 }
+
+//----------------------------------------------------------------------------
+void
+cmCompiledGeneratorExpression::GetMaxLanguageStandard(cmTarget const* tgt,
+                  std::map<std::string, std::string>& mapping)
+{
+  typedef std::map<cmTarget const*,
+                   std::map<std::string, std::string> > MapType;
+  MapType::const_iterator it = this->MaxLanguageStandard.find(tgt);
+  if (it != this->MaxLanguageStandard.end())
+    {
+    mapping = it->second;
+    }
+}