cmGlobalGenerator: Take Build output argument by reference

No call sites pass NULL to the output argument, so take it by
reference to avoid the if(output) conditions.  Propagate the
change through the TryCompile APIs that call it.

Source/CTest/cmCTestBuildAndTestHandler.cxx

@@ -301,7 +301,7 @@ int cmCTestBuildAndTestHandler::RunCMakeAndTest(std::string* outstring)
     int retVal = cm.GetGlobalGenerator()->Build(
       this->SourceDir, this->BinaryDir,
       this->BuildProject, *tarIt,
-      &output, this->BuildMakeProgram,
+      output, this->BuildMakeProgram,
       config,
       !this->BuildNoClean,
       false, remainingTime);

Source/cmCoreTryCompile.cxx

@@ -489,7 +489,7 @@ int cmCoreTryCompile::TryCompileCode(std::vector<std::string> const& argv)
                                        targetName,
                                        this->SrcFileSignature,
                                        &cmakeFlags,
-                                       &output);
+                                       output);
   if ( erroroc )
     {
     cmSystemTools::SetErrorOccured();

Source/cmGlobalGenerator.cxx

@@ -1616,7 +1616,7 @@ int cmGlobalGenerator::TryCompile(const std::string& srcdir,
                                   const std::string& bindir,
                                   const std::string& projectName,
                                   const std::string& target, bool fast,
-                                  std::string *output, cmMakefile *mf)
+                                  std::string& output, cmMakefile *mf)
 {
   // if this is not set, then this is a first time configure
   // and there is a good chance that the try compile stuff will
@@ -1675,7 +1675,7 @@ void cmGlobalGenerator::GenerateBuildCommand(
 int cmGlobalGenerator::Build(
   const std::string&, const std::string& bindir,
   const std::string& projectName, const std::string& target,
-  std::string *output,
+  std::string& output,
   const std::string& makeCommandCSTR,
   const std::string& config,
   bool clean, bool fast,
@@ -1688,22 +1688,15 @@ int cmGlobalGenerator::Build(
    */
   std::string cwd = cmSystemTools::GetCurrentWorkingDirectory();
   cmSystemTools::ChangeDirectory(bindir.c_str());
-  if(output)
-    {
-    *output += "Change Dir: ";
-    *output += bindir;
-    *output += "\n";
-    }
+  output += "Change Dir: ";
+  output += bindir;
+  output += "\n";
 
   int retVal;
   bool hideconsole = cmSystemTools::GetRunCommandHideConsole();
   cmSystemTools::SetRunCommandHideConsole(true);
   std::string outputBuffer;
-  std::string* outputPtr = 0;
-  if(output)
-    {
-    outputPtr = &outputBuffer;
-    }
+  std::string* outputPtr = &outputBuffer;
 
   // should we do a clean first?
   if (clean)
@@ -1711,32 +1704,23 @@ int cmGlobalGenerator::Build(
     std::vector<std::string> cleanCommand;
     this->GenerateBuildCommand(cleanCommand, makeCommandCSTR, projectName,
                                bindir, "clean", config, fast);
-    if(output)
-      {
-      *output += "\nRun Clean Command:";
-      *output += cmSystemTools::PrintSingleCommand(cleanCommand);
-      *output += "\n";
-      }
+    output += "\nRun Clean Command:";
+    output += cmSystemTools::PrintSingleCommand(cleanCommand);
+    output += "\n";
 
     if (!cmSystemTools::RunSingleCommand(cleanCommand, outputPtr,
                                          &retVal, 0, outputflag, timeout))
       {
       cmSystemTools::SetRunCommandHideConsole(hideconsole);
       cmSystemTools::Error("Generator: execution of make clean failed.");
-      if (output)
-        {
-        *output += *outputPtr;
-        *output += "\nGenerator: execution of make clean failed.\n";
-        }
+      output += *outputPtr;
+      output += "\nGenerator: execution of make clean failed.\n";
 
       // return to the original directory
       cmSystemTools::ChangeDirectory(cwd.c_str());
       return 1;
       }
-    if (output)
-      {
-      *output += *outputPtr;
-      }
+    output += *outputPtr;
     }
 
   // now build
@@ -1744,12 +1728,9 @@ int cmGlobalGenerator::Build(
   this->GenerateBuildCommand(makeCommand, makeCommandCSTR, projectName,
                              bindir, target, config, fast, nativeOptions);
   std::string makeCommandStr = cmSystemTools::PrintSingleCommand(makeCommand);
-  if(output)
-    {
-    *output += "\nRun Build Command:";
-    *output += makeCommandStr;
-    *output += "\n";
-    }
+  output += "\nRun Build Command:";
+  output += makeCommandStr;
+  output += "\n";
 
   if (!cmSystemTools::RunSingleCommand(makeCommand, outputPtr,
                                        &retVal, 0, outputflag, timeout))
@@ -1758,27 +1739,21 @@ int cmGlobalGenerator::Build(
     cmSystemTools::Error
       ("Generator: execution of make failed. Make command was: ",
        makeCommandStr.c_str());
-    if (output)
-      {
-      *output += *outputPtr;
-      *output += "\nGenerator: execution of make failed. Make command was: "
+    output += *outputPtr;
+    output += "\nGenerator: execution of make failed. Make command was: "
         + makeCommandStr + "\n";
-      }
 
     // return to the original directory
     cmSystemTools::ChangeDirectory(cwd.c_str());
     return 1;
     }
-  if (output)
-    {
-    *output += *outputPtr;
-    }
+  output += *outputPtr;
   cmSystemTools::SetRunCommandHideConsole(hideconsole);
 
   // The SGI MipsPro 7.3 compiler does not return an error code when
   // the source has a #error in it!  This is a work-around for such
   // compilers.
-  if((retVal == 0) && (output->find("#error") != std::string::npos))
+  if((retVal == 0) && (output.find("#error") != std::string::npos))
     {
     retVal = 1;
     }

Source/cmGlobalGenerator.h

@@ -116,7 +116,7 @@ public:
   virtual int TryCompile(const std::string& srcdir, const std::string& bindir,
                          const std::string& projectName,
                          const std::string& targetName,
-                         bool fast, std::string *output, cmMakefile* mf);
+                         bool fast, std::string& output, cmMakefile* mf);
 
 
   /**
@@ -127,7 +127,7 @@ public:
    */
   int Build(const std::string& srcdir, const std::string& bindir,
             const std::string& projectName, const std::string& targetName,
-            std::string *output,
+            std::string& output,
             const std::string& makeProgram, const std::string& config,
             bool clean, bool fast,
             double timeout,

Source/cmMakefile.cxx

@@ -3510,7 +3510,7 @@ int cmMakefile::TryCompile(const std::string& srcdir,
                            const std::string& targetName,
                            bool fast,
                            const std::vector<std::string> *cmakeArgs,
-                           std::string *output)
+                           std::string& output)
 {
   this->Internal->IsSourceFileTryCompile = fast;
   // does the binary directory exist ? If not create it...

Source/cmMakefile.h

@@ -130,7 +130,7 @@ public:
                  const std::string& projectName, const std::string& targetName,
                  bool fast,
                  const std::vector<std::string> *cmakeArgs,
-                 std::string *output);
+                 std::string& output);
 
   bool GetIsSourceFileTryCompile() const;
 

Source/cmake.cxx

@@ -2757,7 +2757,7 @@ int cmake::Build(const std::string& dir,
   projName = it.GetValue();
   return gen->Build("", dir,
                     projName, target,
-                    &output,
+                    output,
                     "",
                     config, clean, false, 0,
                     cmSystemTools::OUTPUT_PASSTHROUGH,