cmGeneratorTarget: Compute consumed object libraries on demand.

Remove up-front object library computation from cmGlobalGenerator.

Adjust tests for message coming from the generator expression
evaluation.

Source/cmGeneratorTarget.cxx

@@ -503,57 +503,6 @@ void cmGeneratorTarget::GetSourceFiles(std::vector<cmSourceFile*> &files) const
   this->Target->GetSourceFiles(files);
 }
 
-//----------------------------------------------------------------------------
-void cmGeneratorTarget::LookupObjectLibraries()
-{
-  std::vector<std::string> const& objLibs =
-    this->Target->GetObjectLibraries();
-  for(std::vector<std::string>::const_iterator oli = objLibs.begin();
-      oli != objLibs.end(); ++oli)
-    {
-    std::string const& objLibName = *oli;
-    if(cmTarget* objLib = this->Makefile->FindTargetToUse(objLibName))
-      {
-      if(objLib->GetType() == cmTarget::OBJECT_LIBRARY)
-        {
-        if(this->Target->GetType() != cmTarget::EXECUTABLE &&
-           this->Target->GetType() != cmTarget::STATIC_LIBRARY &&
-           this->Target->GetType() != cmTarget::SHARED_LIBRARY &&
-           this->Target->GetType() != cmTarget::MODULE_LIBRARY)
-          {
-          this->GlobalGenerator->GetCMakeInstance()
-            ->IssueMessage(cmake::FATAL_ERROR,
-                           "Only executables and non-OBJECT libraries may "
-                           "reference target objects.",
-                           this->Target->GetBacktrace());
-          return;
-          }
-        this->ObjectLibraries.push_back(objLib);
-        }
-      else
-        {
-        cmOStringStream e;
-        e << "Objects of target \"" << objLibName
-          << "\" referenced but is not an OBJECT library.";
-        this->GlobalGenerator->GetCMakeInstance()
-          ->IssueMessage(cmake::FATAL_ERROR, e.str(),
-                         this->Target->GetBacktrace());
-        return;
-        }
-      }
-    else
-      {
-      cmOStringStream e;
-      e << "Objects of target \"" << objLibName
-        << "\" referenced but no such target exists.";
-      this->GlobalGenerator->GetCMakeInstance()
-        ->IssueMessage(cmake::FATAL_ERROR, e.str(),
-                       this->Target->GetBacktrace());
-      return;
-      }
-    }
-}
-
 //----------------------------------------------------------------------------
 std::string cmGeneratorTarget::GetModuleDefinitionFile() const
 {
@@ -566,9 +515,26 @@ std::string cmGeneratorTarget::GetModuleDefinitionFile() const
 void
 cmGeneratorTarget::UseObjectLibraries(std::vector<std::string>& objs) const
 {
+  std::vector<cmSourceFile const*> objectFiles;
+  this->GetExternalObjects(objectFiles);
+  std::vector<cmTarget*> objectLibraries;
+  std::set<cmTarget*> emitted;
+  for(std::vector<cmSourceFile const*>::const_iterator
+      it = objectFiles.begin(); it != objectFiles.end(); ++it)
+    {
+    std::string objLib = (*it)->GetObjectLibrary();
+    if (cmTarget* tgt = this->Makefile->FindTargetToUse(objLib))
+      {
+      if (emitted.insert(tgt).second)
+        {
+        objectLibraries.push_back(tgt);
+        }
+      }
+    }
+
   for(std::vector<cmTarget*>::const_iterator
-        ti = this->ObjectLibraries.begin();
-      ti != this->ObjectLibraries.end(); ++ti)
+        ti = objectLibraries.begin();
+      ti != objectLibraries.end(); ++ti)
     {
     cmTarget* objLib = *ti;
     cmGeneratorTarget* ogt =

Source/cmGeneratorTarget.h

@@ -84,8 +84,6 @@ public:
    */
   void TraceDependencies();
 
-  void LookupObjectLibraries();
-
   /** Get sources that must be built before the given source.  */
   std::vector<cmSourceFile*> const*
   GetSourceDepends(cmSourceFile const* sf) const;
@@ -127,7 +125,6 @@ private:
 
   std::map<cmSourceFile const*, std::string> Objects;
   std::set<cmSourceFile const*> ExplicitObjectName;
-  std::vector<cmTarget*> ObjectLibraries;
   mutable std::map<std::string, std::vector<std::string> > SystemIncludesCache;
 
   void ConstructSourceFileFlags() const;

Source/cmGlobalGenerator.cxx

@@ -1457,7 +1457,6 @@ void cmGlobalGenerator::ComputeGeneratorTargetObjects()
         continue;
         }
       cmGeneratorTarget* gt = ti->second;
-      gt->LookupObjectLibraries();
       this->ComputeTargetObjects(gt);
       }
     }

Tests/RunCMake/ObjectLibrary/BadSourceExpression2-stderr.txt

@@ -1,4 +1,8 @@
 CMake Error at BadSourceExpression2.cmake:1 \(add_library\):
+  Error evaluating generator expression:
+
+    \$<TARGET_OBJECTS:DoesNotExist>
+
   Objects of target "DoesNotExist" referenced but no such target exists.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)

Tests/RunCMake/ObjectLibrary/BadSourceExpression3-stderr.txt

@@ -1,4 +1,8 @@
 CMake Error at BadSourceExpression3.cmake:2 \(add_library\):
+  Error evaluating generator expression:
+
+    \$<TARGET_OBJECTS:NotObjLib>
+
   Objects of target "NotObjLib" referenced but is not an OBJECT library.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)