Fix internal target lookup performance regression

Refactoring in commit v3.5.0-rc1~272^2~13 (cmGlobalGenerator: Remove
direct storage of targets, 2015-10-25) replaced an efficient data
structure mapping from target name to cmTarget instance with a linear
search.  Lookups through cmGlobalGenerator::FindTarget are done a lot.
Restore the efficient mapping structure with a name indicating its
purpose.

Reported-by: Bartosz Kosiorek <gang65@poczta.onet.pl>

1 files changed, 17 insertions, 1 deletions

diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index bc6e17d..82bb35c 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -278,6 +278,8 @@ public:
   std::set<std::string> const& GetDirectoryContent(std::string const& dir,
                                                    bool needDisk = true);
 
+  void IndexTarget(cmTarget* t);
+
   static bool IsReservedTarget(std::string const& name);
 
   virtual const char* GetAllTargetName()         const { return "ALL_BUILD"; }
@@ -420,7 +422,6 @@ protected:
   std::map<std::string, std::string> AliasTargets;
 
   cmTarget* FindTargetImpl(std::string const& name) const;
-  cmTarget* FindImportedTargetImpl(std::string const& name) const;
 
   cmGeneratorTarget* FindGeneratorTargetImpl(std::string const& name) const;
   cmGeneratorTarget*
@@ -430,6 +431,21 @@ protected:
   virtual bool UseFolderProperty();
 
 private:
+
+#if defined(CMAKE_BUILD_WITH_CMAKE)
+# ifdef CMake_HAVE_CXX11_UNORDERED_MAP
+  typedef std::unordered_map<std::string, cmTarget*> TargetMap;
+# else
+  typedef cmsys::hash_map<std::string, cmTarget*> TargetMap;
+# endif
+#else
+  typedef std::map<std::string,cmTarget *> TargetMap;
+#endif
+  // Map efficiently from target name to cmTarget instance.
+  // Do not use this structure for looping over all targets.
+  // It contains both normal and globally visible imported targets.
+  TargetMap TargetSearchIndex;
+
   cmMakefile* TryCompileOuterMakefile;
   // If you add a new map here, make sure it is copied
   // in EnableLanguagesFromGenerator