Xcode: Fix rebuild with multiple custom command outputs (#15116)

The Xcode generator uses Makefiles under a run-script build-phase to
drive custom commands.  Fix the generated makefiles for custom commands
with multiple outputs to list all the outputs on the left hand side of
the build rule.  This is much simpler and more reliable than the old
multiple-output-pair infrastructure.

Source/cmGlobalXCodeGenerator.cxx

@@ -1498,7 +1498,6 @@ cmGlobalXCodeGenerator::AddCommandsToBuildPhase(cmXCodeObject* buildphase,
                                                 const & commands,
                                                 const char* name)
 {
-  bool haveMultipleOutputPairs = false;
   std::string dir = this->CurrentMakefile->GetCurrentOutputDirectory();
   dir += "/CMakeScripts";
   cmSystemTools::MakeDirectory(dir.c_str());
@@ -1517,8 +1516,7 @@ cmGlobalXCodeGenerator::AddCommandsToBuildPhase(cmXCodeObject* buildphase,
     this->CreateCustomRulesMakefile(makefile.c_str(),
                                     target,
                                     commands,
-                                    currentConfig->c_str(),
-                                    haveMultipleOutputPairs);
+                                    currentConfig->c_str());
     }
 
   std::string cdir = this->CurrentMakefile->GetCurrentOutputDirectory();
@@ -1528,10 +1526,6 @@ cmGlobalXCodeGenerator::AddCommandsToBuildPhase(cmXCodeObject* buildphase,
   makecmd += " -f ";
   makecmd += this->ConvertToRelativeForMake(
                                           (makefile+"$CONFIGURATION").c_str());
-  if(haveMultipleOutputPairs)
-    {
-    makecmd += " cmake_check_multiple_outputs";
-    }
   makecmd += " all";
   cmSystemTools::ReplaceString(makecmd, "\\ ", "\\\\ ");
   buildphase->AddAttribute("shellScript",
@@ -1546,8 +1540,7 @@ void  cmGlobalXCodeGenerator
                             cmTarget& target,
                             std::vector<cmCustomCommand>
                             const & commands,
-                            const std::string& configName,
-                            bool& haveMultipleOutputPairs)
+                            const std::string& configName)
 {
   std::string makefileName=makefileBasename;
   if(this->XcodeVersion > 20)
@@ -1570,7 +1563,6 @@ void  cmGlobalXCodeGenerator
   makefileStream << "all: ";
   std::map<const cmCustomCommand*, std::string> tname;
   int count = 0;
-  std::map<std::string, std::string> multipleOutputPairs;
   for(std::vector<cmCustomCommand>::const_iterator i = commands.begin();
       i != commands.end(); ++i)
     {
@@ -1586,16 +1578,6 @@ void  cmGlobalXCodeGenerator
           makefileStream
               << "\\\n\t" << this->ConvertToRelativeForMake(o->c_str());
           }
-
-        // If there is more than one output treat the first as the
-        // primary output and make the rest depend on it.
-        std::vector<std::string>::const_iterator o = outputs.begin();
-        std::string primaryOutput = this->ConvertToRelativeForMake(o->c_str());
-        for(++o; o != outputs.end(); ++o)
-          {
-          std::string currentOutput=this->ConvertToRelativeForMake(o->c_str());
-          multipleOutputPairs[currentOutput] = primaryOutput;
-          }
         }
       else
         {
@@ -1618,9 +1600,15 @@ void  cmGlobalXCodeGenerator
       if(!outputs.empty())
         {
         // There is at least one output, start the rule for it
-        std::string primary_output =
-            this->ConvertToRelativeForMake(outputs.begin()->c_str());
-        makefileStream << primary_output << ": ";
+        const char* sep = "";
+        for(std::vector<std::string>::const_iterator oi = outputs.begin();
+            oi != outputs.end(); ++oi)
+          {
+          makefileStream << sep <<
+            this->ConvertToRelativeForMake(oi->c_str());
+          sep = " ";
+          }
+        makefileStream << ": ";
         }
       else
         {
@@ -1670,33 +1658,6 @@ void  cmGlobalXCodeGenerator
         }
       }
     }
-
-  // Add rules to deal with multiple outputs of custom commands.
-  if(!multipleOutputPairs.empty())
-    {
-    makefileStream <<
-        "\n# Dependencies of multiple outputs to their primary outputs \n";
-
-    for(std::map<std::string, std::string>::const_iterator o =
-        multipleOutputPairs.begin(); o != multipleOutputPairs.end(); ++o)
-      {
-      makefileStream << o->first << ": " << o->second << "\n";
-      }
-
-    makefileStream <<
-        "\n"
-        "cmake_check_multiple_outputs:\n";
-    for(std::map<std::string, std::string>::const_iterator o =
-        multipleOutputPairs.begin(); o != multipleOutputPairs.end(); ++o)
-      {
-      makefileStream << "\t@if [ ! -f "
-          << o->first << " ]; then rm -f "
-          << o->second << "; fi\n";
-      }
-    }
-
-  haveMultipleOutputPairs =
-    haveMultipleOutputPairs || !multipleOutputPairs.empty();
 }
 
 //----------------------------------------------------------------------------

Source/cmGlobalXCodeGenerator.h

@@ -118,8 +118,7 @@ private:
   void CreateCustomRulesMakefile(const char* makefileBasename,
                                  cmTarget& target,
                                  std::vector<cmCustomCommand> const & commands,
-                                 const std::string& configName,
-                                 bool& haveMultipleOutputPairs);
+                                 const std::string& configName);
 
   cmXCodeObject* FindXCodeTarget(cmTarget const*);
   std::string GetOrCreateId(const std::string& name, const std::string& id);