From c5b26f3bec0e6e18255802da53886eae30a74021 Mon Sep 17 00:00:00 2001
From: Stephen Kelly <steveire@gmail.com>
Date: Sat, 5 Apr 2014 11:40:38 +0200
Subject: cmTarget: Cache the cmSourceFiles in GetSourceFiles.

Avoid calling GetSourceFiles with the same result container multiple
times when tracing target dependencies.  The result from the previous
configuration is cached and used later otherwise.
---
 Source/cmGeneratorTarget.cxx | 18 +++++++++---------
 Source/cmTarget.cxx          | 39 ++++++++++++++++++++++++++++++---------
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 01fad26..69a2977 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -636,26 +636,26 @@ cmTargetTraceDependencies
   // Queue all the source files already specified for the target.
   if (this->Target->GetType() != cmTarget::INTERFACE_LIBRARY)
     {
-    std::vector<std::string> sources;
     std::vector<std::string> configs;
     this->Makefile->GetConfigurations(configs);
     if (configs.empty())
       {
       configs.push_back("");
       }
+    std::set<std::string> emitted;
     for(std::vector<std::string>::const_iterator ci = configs.begin();
         ci != configs.end(); ++ci)
       {
+      std::vector<std::string> sources;
       this->Target->GetSourceFiles(sources, *ci);
-      }
-    std::set<std::string> emitted;
-    for(std::vector<std::string>::const_iterator si = sources.begin();
-        si != sources.end(); ++si)
-      {
-      if(emitted.insert(*si).second && this->SourcesQueued.insert(*si).second)
+      for(std::vector<std::string>::const_iterator si = sources.begin();
+          si != sources.end(); ++si)
         {
-        this->SourceQueue.push(*si);
-        this->Makefile->GetOrCreateSource(*si);
+        if(emitted.insert(*si).second && this->SourcesQueued.insert(*si).second)
+          {
+          this->SourceQueue.push(*si);
+          this->Makefile->GetOrCreateSource(*si);
+          }
         }
       }
     }
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 22be57f..d28ac3f 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -138,6 +138,10 @@ public:
                                                           LinkClosureMapType;
   LinkClosureMapType LinkClosureMap;
 
+  typedef std::map<TargetConfigPair, std::vector<cmSourceFile*> >
+                                                          SourceFilesMapType;
+  SourceFilesMapType SourceFilesMap;
+
   struct TargetPropertyEntry {
     TargetPropertyEntry(cmsys::auto_ptr<cmCompiledGeneratorExpression> cge,
       const std::string &targetName = std::string())
@@ -793,19 +797,33 @@ void cmTarget::GetSourceFiles(std::vector<cmSourceFile*> &files,
                               const std::string& config,
                               cmTarget const* head) const
 {
-  std::vector<std::string> srcs;
-  this->GetSourceFiles(srcs, config, head);
 
-  std::set<cmSourceFile*> emitted;
+  // Lookup any existing link implementation for this configuration.
+  TargetConfigPair key(head, cmSystemTools::UpperCase(config));
 
-  for(std::vector<std::string>::const_iterator i = srcs.begin();
-      i != srcs.end(); ++i)
+  cmTargetInternals::SourceFilesMapType::iterator
+    it = this->Internal->SourceFilesMap.find(key);
+  if(it != this->Internal->SourceFilesMap.end())
+    {
+    files = it->second;
+    }
+  else
     {
-    cmSourceFile* sf = this->Makefile->GetOrCreateSource(*i);
-    if (emitted.insert(sf).second)
+    std::vector<std::string> srcs;
+    this->GetSourceFiles(srcs, config, head);
+
+    std::set<cmSourceFile*> emitted;
+
+    for(std::vector<std::string>::const_iterator i = srcs.begin();
+        i != srcs.end(); ++i)
       {
-      files.push_back(sf);
+      cmSourceFile* sf = this->Makefile->GetOrCreateSource(*i);
+      if (emitted.insert(sf).second)
+        {
+        files.push_back(sf);
+        }
       }
+    this->Internal->SourceFilesMap[key] = files;
     }
 }
 
@@ -835,6 +853,7 @@ void cmTarget::AddSources(std::vector<std::string> const& srcs)
     }
   if (!srcFiles.empty())
     {
+    this->Internal->SourceFilesMap.clear();
     cmListFileBacktrace lfbt;
     this->Makefile->GetBacktrace(lfbt);
     cmGeneratorExpression ge(lfbt);
@@ -969,6 +988,7 @@ cmSourceFile* cmTarget::AddSource(const std::string& src)
                    TargetPropertyEntryFinder(sfl))
                                       == this->Internal->SourceEntries.end())
     {
+    this->Internal->SourceFilesMap.clear();
     cmListFileBacktrace lfbt;
     this->Makefile->GetBacktrace(lfbt);
     cmGeneratorExpression ge(lfbt);
@@ -1738,6 +1758,7 @@ void cmTarget::SetProperty(const std::string& prop, const char* value)
       this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
       return;
       }
+    this->Internal->SourceFilesMap.clear();
     cmListFileBacktrace lfbt;
     this->Makefile->GetBacktrace(lfbt);
     cmGeneratorExpression ge(lfbt);
@@ -1824,7 +1845,7 @@ void cmTarget::AppendProperty(const std::string& prop, const char* value,
       this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
       return;
       }
-
+      this->Internal->SourceFilesMap.clear();
       cmListFileBacktrace lfbt;
       this->Makefile->GetBacktrace(lfbt);
       cmGeneratorExpression ge(lfbt);
-- 
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