Implement interprocedural optimization for GNU compilers

Honor the `INTERPROCEDURAL_OPTIMIZATION` target property for GNU
compilers by activating their link-time-optimization (LTO) flags.

4 files changed, 41 insertions, 14 deletions

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index bb7905019b..c8422d40c9 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -2466,19 +2466,28 @@ void cmGeneratorTarget::GetAppleArchs(const std::string& config,
   }
 }
 
+//----------------------------------------------------------------------------
+std::string cmGeneratorTarget::GetFeatureSpecificLinkRuleVariable(
+  std::string const& var, std::string const& config) const
+{
+  if (this->IsIPOEnabled(config)) {
+    std::string varIPO = var + "_IPO";
+    if (this->Makefile->IsDefinitionSet(varIPO)) {
+      return varIPO;
+    }
+  }
+
+  return var;
+}
+
+//----------------------------------------------------------------------------
 std::string cmGeneratorTarget::GetCreateRuleVariable(
   std::string const& lang, std::string const& config) const
 {
   switch (this->GetType()) {
     case cmStateEnums::STATIC_LIBRARY: {
       std::string var = "CMAKE_" + lang + "_CREATE_STATIC_LIBRARY";
-      if (this->IsIPOEnabled(config)) {
-        std::string varIPO = var + "_IPO";
-        if (this->Makefile->GetDefinition(varIPO)) {
-          return varIPO;
-        }
-      }
-      return var;
+      return this->GetFeatureSpecificLinkRuleVariable(var, config);
     }
     case cmStateEnums::SHARED_LIBRARY:
       return "CMAKE_" + lang + "_CREATE_SHARED_LIBRARY";
diff --git a/Source/cmGeneratorTarget.h b/Source/cmGeneratorTarget.h
index 80bccd5548..2510407a0e 100644
--- a/Source/cmGeneratorTarget.h
+++ b/Source/cmGeneratorTarget.h
@@ -309,6 +309,9 @@ public:
   void GetAppleArchs(const std::string& config,
                      std::vector<std::string>& archVec) const;
 
+  std::string GetFeatureSpecificLinkRuleVariable(
+    std::string const& var, std::string const& config) const;
+
   /** Return the rule variable used to create this type of target.  */
   std::string GetCreateRuleVariable(std::string const& lang,
                                     std::string const& config) const;
diff --git a/Source/cmMakefileLibraryTargetGenerator.cxx b/Source/cmMakefileLibraryTargetGenerator.cxx
index 9ce13ec6be..cc8a6b3f06 100644
--- a/Source/cmMakefileLibraryTargetGenerator.cxx
+++ b/Source/cmMakefileLibraryTargetGenerator.cxx
@@ -129,14 +129,9 @@ void cmMakefileLibraryTargetGenerator::WriteStaticLibraryRules()
 {
   std::string linkLanguage =
     this->GeneratorTarget->GetLinkerLanguage(this->ConfigName);
-  std::string linkRuleVar = "CMAKE_";
-  linkRuleVar += linkLanguage;
-  linkRuleVar += "_CREATE_STATIC_LIBRARY";
 
-  if (this->GeneratorTarget->IsIPOEnabled(this->ConfigName) &&
-      this->Makefile->GetDefinition(linkRuleVar + "_IPO")) {
-    linkRuleVar += "_IPO";
-  }
+  std::string linkRuleVar = this->GeneratorTarget->GetCreateRuleVariable(
+    linkLanguage, this->ConfigName);
 
   std::string extraFlags;
   this->LocalGenerator->GetStaticLibraryFlags(
@@ -676,18 +671,30 @@ void cmMakefileLibraryTargetGenerator::WriteLibraryRules(
     std::string arCreateVar = "CMAKE_";
     arCreateVar += linkLanguage;
     arCreateVar += "_ARCHIVE_CREATE";
+
+    arCreateVar = this->GeneratorTarget->GetFeatureSpecificLinkRuleVariable(
+      arCreateVar, this->ConfigName);
+
     if (const char* rule = this->Makefile->GetDefinition(arCreateVar)) {
       cmSystemTools::ExpandListArgument(rule, archiveCreateCommands);
     }
     std::string arAppendVar = "CMAKE_";
     arAppendVar += linkLanguage;
     arAppendVar += "_ARCHIVE_APPEND";
+
+    arAppendVar = this->GeneratorTarget->GetFeatureSpecificLinkRuleVariable(
+      arAppendVar, this->ConfigName);
+
     if (const char* rule = this->Makefile->GetDefinition(arAppendVar)) {
       cmSystemTools::ExpandListArgument(rule, archiveAppendCommands);
     }
     std::string arFinishVar = "CMAKE_";
     arFinishVar += linkLanguage;
     arFinishVar += "_ARCHIVE_FINISH";
+
+    arFinishVar = this->GeneratorTarget->GetFeatureSpecificLinkRuleVariable(
+      arFinishVar, this->ConfigName);
+
     if (const char* rule = this->Makefile->GetDefinition(arFinishVar)) {
       cmSystemTools::ExpandListArgument(rule, archiveFinishCommands);
     }
diff --git a/Source/cmNinjaNormalTargetGenerator.cxx b/Source/cmNinjaNormalTargetGenerator.cxx
index 5552fa98f7..eac3ecf755 100644
--- a/Source/cmNinjaNormalTargetGenerator.cxx
+++ b/Source/cmNinjaNormalTargetGenerator.cxx
@@ -516,6 +516,10 @@ std::vector<std::string> cmNinjaNormalTargetGenerator::ComputeLinkCmd()
         std::string linkCmdVar = "CMAKE_";
         linkCmdVar += this->TargetLinkLanguage;
         linkCmdVar += "_ARCHIVE_CREATE";
+
+        linkCmdVar = this->GeneratorTarget->GetFeatureSpecificLinkRuleVariable(
+          linkCmdVar, this->GetConfigName());
+
         const char* linkCmd = mf->GetRequiredDefinition(linkCmdVar);
         cmSystemTools::ExpandListArgument(linkCmd, linkCmds);
       }
@@ -523,6 +527,10 @@ std::vector<std::string> cmNinjaNormalTargetGenerator::ComputeLinkCmd()
         std::string linkCmdVar = "CMAKE_";
         linkCmdVar += this->TargetLinkLanguage;
         linkCmdVar += "_ARCHIVE_FINISH";
+
+        linkCmdVar = this->GeneratorTarget->GetFeatureSpecificLinkRuleVariable(
+          linkCmdVar, this->GetConfigName());
+
         const char* linkCmd = mf->GetRequiredDefinition(linkCmdVar);
         cmSystemTools::ExpandListArgument(linkCmd, linkCmds);
       }