cmMakefile::GetRequiredDefinition: return const std::string&

Source/cmExtraCodeBlocksGenerator.cxx

@@ -247,8 +247,8 @@ void cmExtraCodeBlocksGenerator::CreateNewProjectFile(
 
   // figure out the compiler
   std::string compiler = this->GetCBCompilerId(mf);
-  std::string make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
-  const std::string makeArgs =
+  const std::string& make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& makeArgs =
     mf->GetSafeDefinition("CMAKE_CODEBLOCKS_MAKE_ARGUMENTS");
 
   cmXMLWriter xml(fout);

Source/cmExtraCodeLiteGenerator.cxx

@@ -628,8 +628,8 @@ std::string cmExtraCodeLiteGenerator::GetConfigurationName(
 std::string cmExtraCodeLiteGenerator::GetBuildCommand(
   const cmMakefile* mf, const std::string& targetName) const
 {
-  std::string generator = mf->GetSafeDefinition("CMAKE_GENERATOR");
-  std::string make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& generator = mf->GetSafeDefinition("CMAKE_GENERATOR");
+  const std::string& make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
   std::string buildCommand = make; // Default
   std::ostringstream ss;
   if (generator == "NMake Makefiles" || generator == "Ninja") {
@@ -669,8 +669,8 @@ std::string cmExtraCodeLiteGenerator::GetSingleFileBuildCommand(
   const cmMakefile* mf) const
 {
   std::string buildCommand;
-  std::string make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
-  std::string generator = mf->GetSafeDefinition("CMAKE_GENERATOR");
+  const std::string& make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& generator = mf->GetSafeDefinition("CMAKE_GENERATOR");
   if (generator == "Unix Makefiles" || generator == "MinGW Makefiles") {
     std::ostringstream ss;
 #if defined(_WIN32)

Source/cmExtraEclipseCDT4Generator.cxx

@@ -878,8 +878,8 @@ void cmExtraEclipseCDT4Generator::CreateCProjectFile() const
   xml.Attribute("moduleId", "org.eclipse.cdt.make.core.buildtargets");
   xml.StartElement("buildTargets");
   emmited.clear();
-  const std::string make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
-  const std::string makeArgs =
+  const std::string& make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& makeArgs =
     mf->GetSafeDefinition("CMAKE_ECLIPSE_MAKE_ARGUMENTS");
 
   cmGlobalGenerator* generator =
@@ -1074,7 +1074,8 @@ void cmExtraEclipseCDT4Generator::AppendStorageScanners(
   cmXMLWriter& xml, const cmMakefile& makefile)
 {
   // we need the "make" and the C (or C++) compiler which are used, Alex
-  std::string make = makefile.GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& make =
+    makefile.GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
   std::string compiler = makefile.GetSafeDefinition("CMAKE_C_COMPILER");
   std::string arg1 = makefile.GetSafeDefinition("CMAKE_C_COMPILER_ARG1");
   if (compiler.empty()) {

Source/cmExtraKateGenerator.cxx

@@ -75,8 +75,8 @@ void cmExtraKateGenerator::WriteTargets(const cmLocalGenerator* lg,
                                         cmGeneratedFileStream& fout) const
 {
   cmMakefile const* mf = lg->GetMakefile();
-  const std::string make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
-  const std::string makeArgs =
+  const std::string& make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& makeArgs =
     mf->GetSafeDefinition("CMAKE_KATE_MAKE_ARGUMENTS");
   std::string const& homeOutputDir = lg->GetBinaryDirectory();
 

Source/cmExtraSublimeTextGenerator.cxx

@@ -168,7 +168,7 @@ void cmExtraSublimeTextGenerator::AppendAllTargets(
   const std::vector<cmLocalGenerator*>& lgs, const cmMakefile* mf,
   cmGeneratedFileStream& fout, MapSourceFileFlags& sourceFileFlags)
 {
-  std::string make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& make = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
   std::string compiler;
   if (!lgs.empty()) {
     this->AppendTarget(fout, "all", lgs[0], nullptr, make.c_str(), mf,

Source/cmGlobalGenerator.cxx

@@ -680,8 +680,9 @@ void cmGlobalGenerator::EnableLanguage(
         std::string compilerEnv = "CMAKE_";
         compilerEnv += lang;
         compilerEnv += "_COMPILER_ENV_VAR";
-        std::string envVar = mf->GetRequiredDefinition(compilerEnv);
-        std::string envVarValue = mf->GetRequiredDefinition(compilerName);
+        const std::string& envVar = mf->GetRequiredDefinition(compilerEnv);
+        const std::string& envVarValue =
+          mf->GetRequiredDefinition(compilerName);
         std::string env = envVar;
         env += "=";
         env += envVarValue;

Source/cmGlobalMSYSMakefileGenerator.cxx

@@ -45,7 +45,8 @@ void cmGlobalMSYSMakefileGenerator::EnableLanguage(
   std::vector<std::string> const& l, cmMakefile* mf, bool optional)
 {
   this->FindMakeProgram(mf);
-  std::string makeProgram = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& makeProgram =
+    mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
   std::vector<std::string> locations;
   std::string makeloc = cmSystemTools::GetProgramPath(makeProgram.c_str());
   locations.push_back(this->FindMinGW(makeloc));

Source/cmGlobalMinGWMakefileGenerator.cxx

@@ -23,7 +23,8 @@ void cmGlobalMinGWMakefileGenerator::EnableLanguage(
   std::vector<std::string> const& l, cmMakefile* mf, bool optional)
 {
   this->FindMakeProgram(mf);
-  std::string makeProgram = mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
+  const std::string& makeProgram =
+    mf->GetRequiredDefinition("CMAKE_MAKE_PROGRAM");
   std::vector<std::string> locations;
   locations.push_back(cmSystemTools::GetProgramPath(makeProgram));
   locations.push_back("/mingw/bin");

Source/cmInstallTargetGenerator.cxx

@@ -825,7 +825,7 @@ void cmInstallTargetGenerator::AddRanlibRule(std::ostream& os, Indent indent,
     return;
   }
 
-  std::string ranlib =
+  const std::string& ranlib =
     this->Target->Target->GetMakefile()->GetRequiredDefinition("CMAKE_RANLIB");
   if (ranlib.empty()) {
     return;

Source/cmLocalGenerator.cxx

@@ -1364,9 +1364,9 @@ void cmLocalGenerator::OutputLinkLibraries(
 
   std::string linkLanguage = cli.GetLinkLanguage();
 
-  std::string libPathFlag =
+  const std::string& libPathFlag =
     this->Makefile->GetRequiredDefinition("CMAKE_LIBRARY_PATH_FLAG");
-  std::string libPathTerminator =
+  const std::string& libPathTerminator =
     this->Makefile->GetSafeDefinition("CMAKE_LIBRARY_PATH_TERMINATOR");
 
   // Add standard libraries for this language.

Source/cmLocalVisualStudio7Generator.cxx

@@ -931,7 +931,7 @@ std::string cmLocalVisualStudio7Generator::GetBuildTypeLinkerFlags(
   std::string extraLinkOptionsBuildTypeDef =
     rootLinkerFlags + "_" + configTypeUpper;
 
-  std::string extraLinkOptionsBuildType =
+  const std::string& extraLinkOptionsBuildType =
     this->Makefile->GetRequiredDefinition(extraLinkOptionsBuildTypeDef);
 
   return extraLinkOptionsBuildType;
@@ -947,21 +947,18 @@ void cmLocalVisualStudio7Generator::OutputBuildTool(
   std::string extraLinkOptions;
   if (target->GetType() == cmStateEnums::EXECUTABLE) {
     extraLinkOptions =
-      this->Makefile->GetRequiredDefinition("CMAKE_EXE_LINKER_FLAGS") +
-      std::string(" ") +
+      this->Makefile->GetRequiredDefinition("CMAKE_EXE_LINKER_FLAGS") + " " +
       GetBuildTypeLinkerFlags("CMAKE_EXE_LINKER_FLAGS", configName);
   }
   if (target->GetType() == cmStateEnums::SHARED_LIBRARY) {
     extraLinkOptions =
       this->Makefile->GetRequiredDefinition("CMAKE_SHARED_LINKER_FLAGS") +
-      std::string(" ") +
-      GetBuildTypeLinkerFlags("CMAKE_SHARED_LINKER_FLAGS", configName);
+      " " + GetBuildTypeLinkerFlags("CMAKE_SHARED_LINKER_FLAGS", configName);
   }
   if (target->GetType() == cmStateEnums::MODULE_LIBRARY) {
     extraLinkOptions =
       this->Makefile->GetRequiredDefinition("CMAKE_MODULE_LINKER_FLAGS") +
-      std::string(" ") +
-      GetBuildTypeLinkerFlags("CMAKE_MODULE_LINKER_FLAGS", configName);
+      " " + GetBuildTypeLinkerFlags("CMAKE_MODULE_LINKER_FLAGS", configName);
   }
 
   const char* targetLinkFlags = target->GetProperty("LINK_FLAGS");

Source/cmMakefile.cxx

@@ -2425,16 +2425,18 @@ bool cmMakefile::CanIWriteThisFile(std::string const& fileName) const
     cmSystemTools::SameFile(fileName, this->GetHomeOutputDirectory());
 }
 
-std::string cmMakefile::GetRequiredDefinition(const std::string& name) const
+const std::string& cmMakefile::GetRequiredDefinition(
+  const std::string& name) const
 {
-  const char* ret = this->GetDefinition(name);
-  if (!ret) {
+  static std::string const empty;
+  const std::string* def = GetDef(name);
+  if (!def) {
     cmSystemTools::Error("Error required internal CMake variable not "
                          "set, cmake may not be built correctly.\n",
                          "Missing variable is:\n", name.c_str());
-    return std::string();
+    return empty;
   }
-  return std::string(ret);
+  return *def;
 }
 
 bool cmMakefile::IsDefinitionSet(const std::string& name) const

Source/cmMakefile.h

@@ -436,7 +436,7 @@ public:
   const char* GetDefinition(const std::string&) const;
   const std::string* GetDef(const std::string&) const;
   const std::string& GetSafeDefinition(const std::string&) const;
-  std::string GetRequiredDefinition(const std::string& name) const;
+  const std::string& GetRequiredDefinition(const std::string& name) const;
   bool IsDefinitionSet(const std::string&) const;
   /**
    * Get the list of all variables in the current space. If argument

Source/cmMakefileTargetGenerator.cxx

@@ -654,19 +654,20 @@ void cmMakefileTargetGenerator::WriteObjectBuildFile(
       std::string cmdVar;
       if (this->GeneratorTarget->GetPropertyAsBool(
             "CUDA_SEPARABLE_COMPILATION")) {
-        cmdVar = std::string("CMAKE_CUDA_COMPILE_SEPARABLE_COMPILATION");
+        cmdVar = "CMAKE_CUDA_COMPILE_SEPARABLE_COMPILATION";
       } else if (this->GeneratorTarget->GetPropertyAsBool(
                    "CUDA_PTX_COMPILATION")) {
-        cmdVar = std::string("CMAKE_CUDA_COMPILE_PTX_COMPILATION");
+        cmdVar = "CMAKE_CUDA_COMPILE_PTX_COMPILATION";
       } else {
-        cmdVar = std::string("CMAKE_CUDA_COMPILE_WHOLE_COMPILATION");
+        cmdVar = "CMAKE_CUDA_COMPILE_WHOLE_COMPILATION";
       }
-      std::string compileRule = this->Makefile->GetRequiredDefinition(cmdVar);
+      const std::string& compileRule =
+        this->Makefile->GetRequiredDefinition(cmdVar);
       cmSystemTools::ExpandListArgument(compileRule, compileCommands);
     } else {
-      const std::string cmdVar =
-        std::string("CMAKE_") + lang + "_COMPILE_OBJECT";
-      std::string compileRule = this->Makefile->GetRequiredDefinition(cmdVar);
+      const std::string cmdVar = "CMAKE_" + lang + "_COMPILE_OBJECT";
+      const std::string& compileRule =
+        this->Makefile->GetRequiredDefinition(cmdVar);
       cmSystemTools::ExpandListArgument(compileRule, compileCommands);
     }
 

Source/cmNinjaTargetGenerator.cxx

@@ -493,7 +493,7 @@ void cmNinjaTargetGenerator::WriteCompileRule(const std::string& lang)
   if (explicitPP) {
     // Lookup the explicit preprocessing rule.
     std::string const ppVar = "CMAKE_" + lang + "_PREPROCESS_SOURCE";
-    std::string const ppCmd =
+    std::string const& ppCmd =
       this->GetMakefile()->GetRequiredDefinition(ppVar);
 
     // Explicit preprocessing always uses a depfile.
@@ -671,19 +671,18 @@ void cmNinjaTargetGenerator::WriteCompileRule(const std::string& lang)
     std::string cmdVar;
     if (this->GeneratorTarget->GetPropertyAsBool(
           "CUDA_SEPARABLE_COMPILATION")) {
-      cmdVar = std::string("CMAKE_CUDA_COMPILE_SEPARABLE_COMPILATION");
+      cmdVar = "CMAKE_CUDA_COMPILE_SEPARABLE_COMPILATION";
     } else if (this->GeneratorTarget->GetPropertyAsBool(
                  "CUDA_PTX_COMPILATION")) {
-      cmdVar = std::string("CMAKE_CUDA_COMPILE_PTX_COMPILATION");
+      cmdVar = "CMAKE_CUDA_COMPILE_PTX_COMPILATION";
     } else {
-      cmdVar = std::string("CMAKE_CUDA_COMPILE_WHOLE_COMPILATION");
+      cmdVar = "CMAKE_CUDA_COMPILE_WHOLE_COMPILATION";
     }
-    std::string compileCmd = mf->GetRequiredDefinition(cmdVar);
+    const std::string& compileCmd = mf->GetRequiredDefinition(cmdVar);
     cmSystemTools::ExpandListArgument(compileCmd, compileCmds);
   } else {
-    const std::string cmdVar =
-      std::string("CMAKE_") + lang + "_COMPILE_OBJECT";
-    std::string compileCmd = mf->GetRequiredDefinition(cmdVar);
+    const std::string cmdVar = "CMAKE_" + lang + "_COMPILE_OBJECT";
+    const std::string& compileCmd = mf->GetRequiredDefinition(cmdVar);
     cmSystemTools::ExpandListArgument(compileCmd, compileCmds);
   }
 
@@ -1213,20 +1212,19 @@ void cmNinjaTargetGenerator::ExportObjectCompileCommand(
     std::string cmdVar;
     if (this->GeneratorTarget->GetPropertyAsBool(
           "CUDA_SEPARABLE_COMPILATION")) {
-      cmdVar = std::string("CMAKE_CUDA_COMPILE_SEPARABLE_COMPILATION");
+      cmdVar = "CMAKE_CUDA_COMPILE_SEPARABLE_COMPILATION";
     } else if (this->GeneratorTarget->GetPropertyAsBool(
                  "CUDA_PTX_COMPILATION")) {
-      cmdVar = std::string("CMAKE_CUDA_COMPILE_PTX_COMPILATION");
+      cmdVar = "CMAKE_CUDA_COMPILE_PTX_COMPILATION";
     } else {
-      cmdVar = std::string("CMAKE_CUDA_COMPILE_WHOLE_COMPILATION");
+      cmdVar = "CMAKE_CUDA_COMPILE_WHOLE_COMPILATION";
     }
-    std::string compileCmd =
+    const std::string& compileCmd =
       this->GetMakefile()->GetRequiredDefinition(cmdVar);
     cmSystemTools::ExpandListArgument(compileCmd, compileCmds);
   } else {
-    const std::string cmdVar =
-      std::string("CMAKE_") + language + "_COMPILE_OBJECT";
-    std::string compileCmd =
+    const std::string cmdVar = "CMAKE_" + language + "_COMPILE_OBJECT";
+    const std::string& compileCmd =
       this->GetMakefile()->GetRequiredDefinition(cmdVar);
     cmSystemTools::ExpandListArgument(compileCmd, compileCmds);
   }

Source/cmUtilitySourceCommand.cxx

@@ -79,7 +79,7 @@ bool cmUtilitySourceCommand::InitialPass(std::vector<std::string> const& args,
   }
 
   // The source exists.
-  std::string cmakeCFGout =
+  const std::string& cmakeCFGout =
     this->Makefile->GetRequiredDefinition("CMAKE_CFG_INTDIR");
   std::string utilityDirectory = this->Makefile->GetCurrentBinaryDirectory();
   std::string exePath;