Genex: Only evaluate TARGET_OBJECTS to determine target sources.

The output of this expression may contain macros for IDEs to replace
such as $(Configuration), $(CURRENT_ARCH) etc.  To avoid generating
content which is not usable in other contexts, report an error if
there is an attempt to use it in other contexts.

This commit may be reverted in the future if a solution to the
above difference is implemented.

5 files changed, 21 insertions, 1 deletions

diff --git a/Source/cmGeneratorExpression.cxx b/Source/cmGeneratorExpression.cxx
index e127f3a..d09e950 100644
--- a/Source/cmGeneratorExpression.cxx
+++ b/Source/cmGeneratorExpression.cxx
@@ -90,6 +90,7 @@ const char *cmCompiledGeneratorExpression::Evaluate(
   context.HadError = false;
   context.HadContextSensitiveCondition = false;
   context.HeadTarget = headTarget;
+  context.EvaluateForBuildsystem = this->EvaluateForBuildsystem;
   context.CurrentTarget = currentTarget ? currentTarget : headTarget;
   context.Backtrace = this->Backtrace;
 
@@ -124,7 +125,8 @@ cmCompiledGeneratorExpression::cmCompiledGeneratorExpression(
               cmListFileBacktrace const& backtrace,
               const std::string& input)
   : Backtrace(backtrace), Input(input),
-    HadContextSensitiveCondition(false)
+    HadContextSensitiveCondition(false),
+    EvaluateForBuildsystem(false)
 {
   cmGeneratorExpressionLexer l;
   std::vector<cmGeneratorExpressionToken> tokens =
diff --git a/Source/cmGeneratorExpression.h b/Source/cmGeneratorExpression.h
index d0a6aef..da64515 100644
--- a/Source/cmGeneratorExpression.h
+++ b/Source/cmGeneratorExpression.h
@@ -112,6 +112,11 @@ public:
     return this->HadContextSensitiveCondition;
   }
 
+  void SetEvaluateForBuildsystem(bool eval)
+  {
+    this->EvaluateForBuildsystem = eval;
+  }
+
 private:
   cmCompiledGeneratorExpression(cmListFileBacktrace const& backtrace,
               const std::string& input);
@@ -131,6 +136,7 @@ private:
   mutable std::set<std::string> SeenTargetProperties;
   mutable std::string Output;
   mutable bool HadContextSensitiveCondition;
+  bool EvaluateForBuildsystem;
 };
 
 #endif
diff --git a/Source/cmGeneratorExpressionEvaluator.cxx b/Source/cmGeneratorExpressionEvaluator.cxx
index 669694c..95227d2 100644
--- a/Source/cmGeneratorExpressionEvaluator.cxx
+++ b/Source/cmGeneratorExpressionEvaluator.cxx
@@ -1251,6 +1251,16 @@ static const struct TargetObjectsNode : public cmGeneratorExpressionNode
                        const GeneratorExpressionContent *content,
                        cmGeneratorExpressionDAGChecker *) const
   {
+    if (!context->EvaluateForBuildsystem)
+      {
+      cmOStringStream e;
+      e << "The evaluation of the TARGET_OBJECTS generator expression "
+        "is only suitable for consumption by CMake.  It is not suitable "
+        "for writing out elsewhere.";
+      reportError(context, content->GetOriginalExpression(), e.str());
+      return std::string();
+      }
+
     std::string tgtName = parameters.front();
     cmGeneratorTarget* gt =
                 context->Makefile->FindGeneratorTargetToUse(tgtName.c_str());
diff --git a/Source/cmGeneratorExpressionEvaluator.h b/Source/cmGeneratorExpressionEvaluator.h
index a7099cb..54a2548 100644
--- a/Source/cmGeneratorExpressionEvaluator.h
+++ b/Source/cmGeneratorExpressionEvaluator.h
@@ -34,6 +34,7 @@ struct cmGeneratorExpressionContext
   bool Quiet;
   bool HadError;
   bool HadContextSensitiveCondition;
+  bool EvaluateForBuildsystem;
 };
 
 struct cmGeneratorExpressionDAGChecker;
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 61260be..aeb477d 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -732,6 +732,7 @@ cmSourceFile* cmTarget::AddSource(const std::string& src)
     this->Makefile->GetBacktrace(lfbt);
     cmGeneratorExpression ge(lfbt);
     cmsys::auto_ptr<cmCompiledGeneratorExpression> cge = ge.Parse(src);
+    cge->SetEvaluateForBuildsystem(true);
     this->Internal->SourceEntries.push_back(
                           new cmTargetInternals::TargetPropertyEntry(cge));
     }