Add a new Export generator for IMPORTED targets.

This is to be used during try_compile using LINK_LIBRARIES in the
srcfile signature and, in the future, TARGETS in the binary dir
signature.

Source/CMakeLists.txt

@@ -176,6 +176,8 @@ set(SRCS
   cmExportFileGenerator.cxx
   cmExportInstallFileGenerator.h
   cmExportInstallFileGenerator.cxx
+  cmExportTryCompileFileGenerator.h
+  cmExportTryCompileFileGenerator.cxx
   cmExportSet.h
   cmExportSet.cxx
   cmExportSetMap.h

Source/cmExportFileGenerator.cxx

@@ -679,6 +679,9 @@ cmExportFileGenerator
     case cmTarget::MODULE_LIBRARY:
       os << "add_library(" << targetName << " MODULE IMPORTED)\n";
       break;
+    case cmTarget::UNKNOWN_LIBRARY:
+      os << "add_library(" << targetName << " UNKNOWN IMPORTED)\n";
+      break;
     default:  // should never happen
       break;
     }

Source/cmExportTryCompileFileGenerator.cxx

@@ -0,0 +1,114 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  Copyright 2013 Stephen Kelly <steveire@gmail.com>
+
+  Distributed under the OSI-approved BSD License (the "License");
+  see accompanying file Copyright.txt for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even the
+  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the License for more information.
+============================================================================*/
+
+#include "cmExportTryCompileFileGenerator.h"
+
+#include "cmGeneratedFileStream.h"
+#include "cmGeneratorExpressionDAGChecker.h"
+
+//----------------------------------------------------------------------------
+bool cmExportTryCompileFileGenerator::GenerateMainFile(std::ostream& os)
+{
+  std::set<cmTarget*> emitted;
+  std::set<cmTarget*> emittedDeps;
+  while(!this->Exports.empty())
+    {
+    cmTarget* te = this->Exports.back();
+    this->Exports.pop_back();
+    if (emitted.insert(te).second)
+      {
+      emittedDeps.insert(te);
+      this->GenerateImportTargetCode(os, te);
+
+      ImportPropertyMap properties;
+
+      this->FindTargets("INTERFACE_INCLUDE_DIRECTORIES", te, emittedDeps);
+      this->FindTargets("INTERFACE_COMPILE_DEFINITIONS", te, emittedDeps);
+
+      this->PopulateProperties(te, properties, emittedDeps);
+
+      this->GenerateInterfaceProperties(te, os, properties);
+      }
+    }
+  return true;
+}
+
+std::string cmExportTryCompileFileGenerator::FindTargets(const char *propName,
+                                                cmTarget *tgt,
+                                                std::set<cmTarget*> &emitted)
+{
+  const char *prop = tgt->GetProperty(propName);
+  if(!prop)
+    {
+    return std::string();
+    }
+
+  cmListFileBacktrace lfbt;
+  cmGeneratorExpression ge(lfbt);
+
+  cmGeneratorExpressionDAGChecker dagChecker(lfbt,
+                                      tgt->GetName(),
+                                      propName, 0, 0);
+
+  cmsys::auto_ptr<cmCompiledGeneratorExpression> cge = ge.Parse(prop);
+
+  cmTarget dummyHead;
+  dummyHead.SetType(cmTarget::EXECUTABLE, "try_compile_dummy_exe");
+  dummyHead.SetMakefile(tgt->GetMakefile());
+
+  std::string result = cge->Evaluate(tgt->GetMakefile(), this->Config,
+                                     false, &dummyHead, tgt, &dagChecker);
+
+  const std::set<cmTarget*> &allTargets = cge->GetAllTargetsSeen();
+  for(std::set<cmTarget*>::const_iterator li = allTargets.begin();
+      li != allTargets.end(); ++li)
+    {
+    if(emitted.insert(*li).second)
+      {
+      this->Exports.push_back(*li);
+      }
+    }
+  return result;
+}
+
+//----------------------------------------------------------------------------
+void
+cmExportTryCompileFileGenerator::PopulateProperties(cmTarget* target,
+                                                ImportPropertyMap& properties,
+                                                std::set<cmTarget*> &emitted)
+{
+  cmPropertyMap props = target->GetProperties();
+  for(cmPropertyMap::const_iterator i = props.begin(); i != props.end(); ++i)
+    {
+    properties[i->first] = i->second.GetValue();
+
+    if(i->first.find("IMPORTED_LINK_INTERFACE_LIBRARIES") == 0)
+      {
+      const std::string libs = i->second.GetValue();
+
+      std::string evalResult = this->FindTargets(i->first.c_str(),
+                                                 target, emitted);
+
+      std::vector<std::string> depends;
+      cmSystemTools::ExpandListArgument(evalResult, depends);
+      for(std::vector<std::string>::const_iterator li = depends.begin();
+          li != depends.end(); ++li)
+        {
+        cmTarget *tgt = target->GetMakefile()->FindTargetToUse(li->c_str());
+        if(tgt && emitted.insert(tgt).second)
+          {
+          this->Exports.push_back(tgt);
+          }
+        }
+      }
+    }
+}

Source/cmExportTryCompileFileGenerator.h

@@ -0,0 +1,55 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  Copyright 2013 Stephen Kelly <steveire@gmail.com>
+
+  Distributed under the OSI-approved BSD License (the "License");
+  see accompanying file Copyright.txt for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even the
+  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the License for more information.
+============================================================================*/
+#ifndef cmExportInstallFileGenerator_h
+#define cmExportInstallFileGenerator_h
+
+#include "cmExportFileGenerator.h"
+
+class cmInstallExportGenerator;
+class cmInstallTargetGenerator;
+
+class cmExportTryCompileFileGenerator: public cmExportFileGenerator
+{
+public:
+  /** Set the list of targets to export.  */
+  void SetExports(const std::vector<cmTarget*> &exports)
+    { this->Exports = exports; }
+  void SetConfig(const char *config) { this->Config = config; }
+protected:
+
+  // Implement virtual methods from the superclass.
+  virtual bool GenerateMainFile(std::ostream& os);
+
+  virtual void GenerateImportTargetsConfig(std::ostream&,
+                                           const char*,
+                                           std::string const&,
+                            std::vector<std::string>&) {}
+  virtual void HandleMissingTarget(std::string&,
+                                   std::vector<std::string>&,
+                                   cmMakefile*,
+                                   cmTarget*,
+                                   cmTarget*) {}
+
+  void PopulateProperties(cmTarget* target,
+                          ImportPropertyMap& properties,
+                          std::set<cmTarget*> &emitted);
+
+private:
+  std::string FindTargets(const char *prop, cmTarget *tgt,
+                   std::set<cmTarget*> &emitted);
+
+
+  std::vector<cmTarget*> Exports;
+  const char *Config;
+};
+
+#endif

bootstrap

@@ -214,6 +214,7 @@ CMAKE_CXX_SOURCES="\
   cmMakefile \
   cmExportFileGenerator \
   cmExportInstallFileGenerator \
+  cmExportTryCompileFileGenerator \
   cmExportSet \
   cmExportSetMap \
   cmInstallDirectoryGenerator \