Add the $<LINKED:...> generator expression.

This is both a short form of using a TARGET_DEFINED expression
together with a TARGET_PROPERTY definition, and a way to strip
non-target content from interface properties when exporting.

1 files changed, 85 insertions, 0 deletions

diff --git a/Source/cmGeneratorExpressionEvaluator.cxx b/Source/cmGeneratorExpressionEvaluator.cxx
index fff7dab..cbea1d9 100644
--- a/Source/cmGeneratorExpressionEvaluator.cxx
+++ b/Source/cmGeneratorExpressionEvaluator.cxx
@@ -638,6 +638,89 @@ static const struct InstallPrefixNode : public cmGeneratorExpressionNode
 } installPrefixNode;
 
 //----------------------------------------------------------------------------
+static const struct LinkedNode : public cmGeneratorExpressionNode
+{
+  LinkedNode() {}
+
+  virtual bool GeneratesContent() const { return true; }
+  virtual int NumExpectedParameters() const { return 1; }
+  virtual bool RequiresLiteralInput() const { return true; }
+
+  std::string Evaluate(const std::vector<std::string> &parameters,
+                       cmGeneratorExpressionContext *context,
+                       const GeneratorExpressionContent *content,
+                       cmGeneratorExpressionDAGChecker *dagChecker) const
+  {
+    if (dagChecker->EvaluatingIncludeDirectories())
+      {
+      return this->GetInterfaceProperty(parameters.front(),
+                                        "INCLUDE_DIRECTORIES",
+                                        context, content, dagChecker);
+      }
+    if (dagChecker->EvaluatingCompileDefinitions())
+      {
+      return this->GetInterfaceProperty(parameters.front(),
+                                        "COMPILE_DEFINITIONS",
+                                        context, content, dagChecker);
+      }
+
+    reportError(context, content->GetOriginalExpression(),
+                "$<LINKED:...> may only be used in INCLUDE_DIRECTORIES and "
+                "COMPILE_DEFINITIONS properties.");
+
+    return std::string();
+  }
+
+private:
+  std::string GetInterfaceProperty(const std::string &item,
+                      const std::string &prop,
+                      cmGeneratorExpressionContext *context,
+                      const GeneratorExpressionContent *content,
+                      cmGeneratorExpressionDAGChecker *dagCheckerParent) const
+  {
+    cmTarget *target = context->CurrentTarget
+                              ->GetMakefile()->FindTargetToUse(item.c_str());
+    if (!target)
+      {
+      return std::string();
+      }
+    std::string propertyName = "INTERFACE_" + prop;
+    const char *propContent = target->GetProperty(propertyName.c_str());
+    if (!propContent)
+      {
+      return std::string();
+      }
+
+    cmGeneratorExpressionDAGChecker dagChecker(context->Backtrace,
+                                               target->GetName(),
+                                               propertyName,
+                                               content,
+                                               dagCheckerParent);
+
+    switch (dagChecker.check())
+      {
+    case cmGeneratorExpressionDAGChecker::SELF_REFERENCE:
+      dagChecker.reportError(context, content->GetOriginalExpression());
+      return std::string();
+    case cmGeneratorExpressionDAGChecker::CYCLIC_REFERENCE:
+      // No error. We just skip cyclic references.
+      return std::string();
+    case cmGeneratorExpressionDAGChecker::DAG:
+      break;
+      }
+
+    cmGeneratorExpression ge(context->Backtrace);
+    return ge.Parse(propContent)->Evaluate(context->Makefile,
+                        context->Config,
+                        context->Quiet,
+                        context->HeadTarget,
+                        target,
+                        &dagChecker);
+  }
+
+} linkedNode;
+
+//----------------------------------------------------------------------------
 template<bool linker, bool soname>
 struct TargetFilesystemArtifactResultCreator
 {
@@ -874,6 +957,8 @@ cmGeneratorExpressionNode* GetNode(const std::string &identifier)
     return &targetDefinedNode;
   else if (identifier == "INSTALL_PREFIX")
     return &installPrefixNode;
+  else if (identifier == "LINKED")
+    return &linkedNode;
   return 0;
 
 }