Clang IPO (LTO) support

4 files changed, 45 insertions, 3 deletions

diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 57b744c..33e32d1 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -915,6 +915,9 @@ void cmLocalGenerator::GetTargetFlags(
   const char* libraryLinkVariable =
     "CMAKE_SHARED_LINKER_FLAGS"; // default to shared library
 
+  const std::string linkLanguage =
+    linkLineComputer->GetLinkerLanguage(target, buildType);
+
   switch (target->GetType()) {
     case cmStateEnums::STATIC_LIBRARY:
       this->GetStaticLibraryFlags(linkFlags, buildType, target);
@@ -976,9 +979,6 @@ void cmLocalGenerator::GetTargetFlags(
         linkFlags += this->Makefile->GetSafeDefinition(build);
         linkFlags += " ";
       }
-
-      const std::string linkLanguage =
-        linkLineComputer->GetLinkerLanguage(target, buildType);
       if (linkLanguage.empty()) {
         cmSystemTools::Error(
           "CMake can not determine linker language for target: ",
@@ -1040,6 +1040,8 @@ void cmLocalGenerator::GetTargetFlags(
     default:
       break;
   }
+
+  this->AppendIPOLinkerFlags(linkFlags, target, config, linkLanguage);
 }
 
 void cmLocalGenerator::GetTargetCompileFlags(cmGeneratorTarget* target,
@@ -1769,6 +1771,38 @@ void cmLocalGenerator::AppendFlagEscape(std::string& flags,
   this->AppendFlags(flags, this->EscapeForShell(rawFlag));
 }
 
+void cmLocalGenerator::AppendIPOLinkerFlags(std::string& flags,
+                                            cmGeneratorTarget* target,
+                                            const std::string& config,
+                                            const std::string& lang)
+{
+  if (!target->IsIPOEnabled(config)) {
+    return;
+  }
+
+  switch (target->GetType()) {
+    case cmStateEnums::EXECUTABLE:
+    case cmStateEnums::SHARED_LIBRARY:
+    case cmStateEnums::MODULE_LIBRARY:
+      break;
+    default:
+      return;
+  }
+
+  const std::string name = "CMAKE_" + lang + "_LINK_OPTIONS_IPO";
+  const char* rawFlagsList = this->Makefile->GetDefinition(name);
+  if (rawFlagsList == CM_NULLPTR) {
+    return;
+  }
+
+  std::vector<std::string> flagsList;
+  cmSystemTools::ExpandListArgument(rawFlagsList, flagsList);
+  for (std::vector<std::string>::const_iterator oi = flagsList.begin();
+       oi != flagsList.end(); ++oi) {
+    this->AppendFlagEscape(flags, *oi);
+  }
+}
+
 void cmLocalGenerator::AppendDefines(std::set<std::string>& defines,
                                      const char* defines_list) const
 {
diff --git a/Source/cmLocalGenerator.h b/Source/cmLocalGenerator.h
index 2eda0e5..1a238a8 100644
--- a/Source/cmLocalGenerator.h
+++ b/Source/cmLocalGenerator.h
@@ -115,6 +115,9 @@ public:
   virtual void AppendFlags(std::string& flags, const char* newFlags);
   virtual void AppendFlagEscape(std::string& flags,
                                 const std::string& rawFlag);
+  void AppendIPOLinkerFlags(std::string& flags, cmGeneratorTarget* target,
+                            const std::string& config,
+                            const std::string& lang);
   ///! Get the include flags for the current makefile and language
   std::string GetIncludeFlags(const std::vector<std::string>& includes,
                               cmGeneratorTarget* target,
diff --git a/Source/cmMakefileExecutableTargetGenerator.cxx b/Source/cmMakefileExecutableTargetGenerator.cxx
index 272d45b..fb39f01 100644
--- a/Source/cmMakefileExecutableTargetGenerator.cxx
+++ b/Source/cmMakefileExecutableTargetGenerator.cxx
@@ -457,6 +457,9 @@ void cmMakefileExecutableTargetGenerator::WriteExecutableRule(bool relink)
     this->AddModuleDefinitionFlag(linkLineComputer.get(), linkFlags);
   }
 
+  this->LocalGenerator->AppendIPOLinkerFlags(linkFlags, this->GeneratorTarget,
+                                             this->ConfigName, linkLanguage);
+
   // Construct a list of files associated with this executable that
   // may need to be cleaned.
   std::vector<std::string> exeCleanFiles;
diff --git a/Source/cmMakefileLibraryTargetGenerator.cxx b/Source/cmMakefileLibraryTargetGenerator.cxx
index ec01208..5ee9f45 100644
--- a/Source/cmMakefileLibraryTargetGenerator.cxx
+++ b/Source/cmMakefileLibraryTargetGenerator.cxx
@@ -494,6 +494,8 @@ void cmMakefileLibraryTargetGenerator::WriteLibraryRules(
   // Create set of linking flags.
   std::string linkFlags;
   this->LocalGenerator->AppendFlags(linkFlags, extraFlags);
+  this->LocalGenerator->AppendIPOLinkerFlags(linkFlags, this->GeneratorTarget,
+                                             this->ConfigName, linkLanguage);
 
   // Add OSX version flags, if any.
   if (this->GeneratorTarget->GetType() == cmStateEnums::SHARED_LIBRARY ||