Exemplo n.º 1
0
        /// <summary>
        /// Given a set of C++ files, generates another set of C++ files that #include all the original
        /// files, the goal being to compile the same code in fewer translation units.
        /// The "unity" files are written to the CompileEnvironment's OutputDirectory.
        /// </summary>
        /// <param name="Target">The target we're building</param>
        /// <param name="CPPFiles">The C++ files to #include.</param>
        /// <param name="CompileEnvironment">The environment that is used to compile the C++ files.</param>
        /// <param name="WorkingSet">Interface to query files which belong to the working set</param>
        /// <param name="BaseName">Base name to use for the Unity files</param>
        /// <param name="IntermediateDirectory">Intermediate directory for unity cpp files</param>
        /// <param name="Makefile">The makefile being built</param>
        /// <param name="SourceFileToUnityFile">Receives a mapping of source file to unity file</param>
        /// <returns>The "unity" C++ files.</returns>
        public static List <FileItem> GenerateUnityCPPs(
            ReadOnlyTargetRules Target,
            List <FileItem> CPPFiles,
            CppCompileEnvironment CompileEnvironment,
            ISourceFileWorkingSet WorkingSet,
            string BaseName,
            DirectoryReference IntermediateDirectory,
            TargetMakefile Makefile,
            Dictionary <FileItem, FileItem> SourceFileToUnityFile
            )
        {
            List <FileItem> NewCPPFiles = new List <FileItem>();

            UEBuildPlatform BuildPlatform = UEBuildPlatform.GetBuildPlatform(CompileEnvironment.Platform);

            // Figure out size of all input files combined. We use this to determine whether to use larger unity threshold or not.
            long TotalBytesInCPPFiles = CPPFiles.Sum(F => F.Length);

            // We have an increased threshold for unity file size if, and only if, all files fit into the same unity file. This
            // is beneficial when dealing with PCH files. The default PCH creation limit is X unity files so if we generate < X
            // this could be fairly slow and we'd rather bump the limit a bit to group them all into the same unity file.


            // When enabled, UnrealBuildTool will try to determine source files that you are actively iteratively changing, and break those files
            // out of their unity blobs so that you can compile them as individual translation units, much faster than recompiling the entire
            // unity blob each time.
            bool bUseAdaptiveUnityBuild = Target.bUseAdaptiveUnityBuild && !Target.bStressTestUnity;

            // Optimization only makes sense if PCH files are enabled.
            bool bForceIntoSingleUnityFile = Target.bStressTestUnity || (TotalBytesInCPPFiles < Target.NumIncludedBytesPerUnityCPP * 2 && Target.bUsePCHFiles);

            // Build the list of unity files.
            List <FileCollection> AllUnityFiles;
            {
                // Sort the incoming file paths alphabetically, so there will be consistency in unity blobs across multiple machines.
                // Note that we're relying on this not only sorting files within each directory, but also the directories
                // themselves, so the whole list of file paths is the same across computers.
                List <FileItem> SortedCPPFiles = CPPFiles.GetRange(0, CPPFiles.Count);
                {
                    // Case-insensitive file path compare, because you never know what is going on with local file systems
                    Comparison <FileItem> FileItemComparer = (FileA, FileB) => { return(FileA.AbsolutePath.ToLowerInvariant().CompareTo(FileB.AbsolutePath.ToLowerInvariant())); };
                    SortedCPPFiles.Sort(FileItemComparer);
                }


                // Figure out whether we REALLY want to use adaptive unity for this module.  If nearly every file in the module appears in the working
                // set, we'll just go ahead and let unity build do its thing.
                if (bUseAdaptiveUnityBuild)
                {
                    int CandidateWorkingSetSourceFileCount = 0;
                    int WorkingSetSourceFileCount          = 0;
                    foreach (FileItem CPPFile in SortedCPPFiles)
                    {
                        ++CandidateWorkingSetSourceFileCount;

                        // Don't include writable source files into unity blobs
                        if (WorkingSet.Contains(CPPFile))
                        {
                            ++WorkingSetSourceFileCount;

                            // Mark this file as part of the working set.  This will be saved into the UBT Makefile so that
                            // the assembler can automatically invalidate the Makefile when the working set changes (allowing this
                            // code to run again, to build up new unity blobs.)
                            Makefile.WorkingSet.Add(CPPFile);
                        }
                    }

                    if (WorkingSetSourceFileCount >= CandidateWorkingSetSourceFileCount)
                    {
                        // Every single file in the module appears in the working set, so don't bother using adaptive unity for this
                        // module.  Otherwise it would make full builds really slow.
                        bUseAdaptiveUnityBuild = false;
                    }
                }

                UnityFileBuilder CPPUnityFileBuilder          = new UnityFileBuilder(bForceIntoSingleUnityFile ? -1 : Target.NumIncludedBytesPerUnityCPP);
                StringBuilder    AdaptiveUnityBuildInfoString = new StringBuilder();
                foreach (FileItem CPPFile in SortedCPPFiles)
                {
                    if (!bForceIntoSingleUnityFile && CPPFile.AbsolutePath.IndexOf(".GeneratedWrapper.", StringComparison.InvariantCultureIgnoreCase) != -1)
                    {
                        NewCPPFiles.Add(CPPFile);
                    }

                    // When adaptive unity is enabled, go ahead and exclude any source files that we're actively working with
                    if (bUseAdaptiveUnityBuild && Makefile.WorkingSet.Contains(CPPFile))
                    {
                        // Just compile this file normally, not as part of the unity blob
                        NewCPPFiles.Add(CPPFile);

                        // Let the unity file builder know about the file, so that we can retain the existing size of the unity blobs.
                        // This won't actually make the source file part of the unity blob, but it will keep track of how big the
                        // file is so that other existing unity blobs from the same module won't be invalidated.  This prevents much
                        // longer compile times the first time you build after your working file set changes.
                        CPPUnityFileBuilder.AddVirtualFile(CPPFile);

                        string CPPFileName = Path.GetFileName(CPPFile.AbsolutePath);
                        if (AdaptiveUnityBuildInfoString.Length == 0)
                        {
                            AdaptiveUnityBuildInfoString.Append(String.Format("[Adaptive unity build] Excluded from {0} unity file: {1}", BaseName, CPPFileName));
                        }
                        else
                        {
                            AdaptiveUnityBuildInfoString.Append(", " + CPPFileName);
                        }
                    }
                    else
                    {
                        // If adaptive unity build is enabled for this module, add this source file to the set that will invalidate the makefile
                        if (bUseAdaptiveUnityBuild)
                        {
                            Makefile.CandidatesForWorkingSet.Add(CPPFile);
                        }

                        // Compile this file as part of the unity blob
                        CPPUnityFileBuilder.AddFile(CPPFile);
                    }
                }

                if (AdaptiveUnityBuildInfoString.Length > 0)
                {
                    if (Target.bAdaptiveUnityCreatesDedicatedPCH)
                    {
                        AddUniqueDiagnostic(Makefile, "[Adaptive unity build] Creating dedicated PCH for each excluded file. Set bAdaptiveUnityCreatesDedicatedPCH to false in BuildConfiguration.xml to change this behavior.");
                    }
                    else if (Target.bAdaptiveUnityDisablesPCH)
                    {
                        AddUniqueDiagnostic(Makefile, "[Adaptive unity build] Disabling PCH for excluded files. Set bAdaptiveUnityDisablesPCH to false in BuildConfiguration.xml to change this behavior.");
                    }

                    if (Target.bAdaptiveUnityDisablesOptimizations)
                    {
                        AddUniqueDiagnostic(Makefile, "[Adaptive unity build] Disabling optimizations for excluded files. Set bAdaptiveUnityDisablesOptimizations to false in BuildConfiguration.xml to change this behavior.");
                    }
                    if (Target.bAdaptiveUnityEnablesEditAndContinue)
                    {
                        AddUniqueDiagnostic(Makefile, "[Adaptive unity build] Enabling Edit & Continue for excluded files. Set bAdaptiveUnityEnablesEditAndContinue to false in BuildConfiguration.xml to change this behavior.");
                    }

                    Makefile.Diagnostics.Add(AdaptiveUnityBuildInfoString.ToString());
                }

                AllUnityFiles = CPPUnityFileBuilder.GetUnityFiles();
            }

            // Create a set of CPP files that combine smaller CPP files into larger compilation units, along with the corresponding
            // actions to compile them.
            int CurrentUnityFileCount = 0;

            foreach (FileCollection UnityFile in AllUnityFiles)
            {
                ++CurrentUnityFileCount;

                StringWriter OutputUnityCPPWriter = new StringWriter();

                OutputUnityCPPWriter.WriteLine("// This file is automatically generated at compile-time to include some subset of the user-created cpp files.");

                // Add source files to the unity file
                foreach (FileItem CPPFile in UnityFile.Files)
                {
                    OutputUnityCPPWriter.WriteLine("#include \"{0}\"", CPPFile.AbsolutePath.Replace('\\', '/'));
                }

                // Determine unity file path name
                string UnityCPPFileName;
                if (AllUnityFiles.Count > 1)
                {
                    UnityCPPFileName = string.Format("{0}{1}.{2}_of_{3}.cpp", ModulePrefix, BaseName, CurrentUnityFileCount, AllUnityFiles.Count);
                }
                else
                {
                    UnityCPPFileName = string.Format("{0}{1}.cpp", ModulePrefix, BaseName);
                }
                FileReference UnityCPPFilePath = FileReference.Combine(IntermediateDirectory, UnityCPPFileName);

                // Write the unity file to the intermediate folder.
                FileItem UnityCPPFile = FileItem.CreateIntermediateTextFile(UnityCPPFilePath, OutputUnityCPPWriter.ToString());
                NewCPPFiles.Add(UnityCPPFile);

                // Store the mapping of source files to unity files in the makefile
                foreach (FileItem SourceFile in UnityFile.Files)
                {
                    SourceFileToUnityFile[SourceFile] = UnityCPPFile;
                }
                foreach (FileItem SourceFile in UnityFile.VirtualFiles)
                {
                    SourceFileToUnityFile[SourceFile] = UnityCPPFile;
                }
            }

            return(NewCPPFiles);
        }
Exemplo n.º 2
0
        /// <summary>
        /// Given a set of C++ files, generates another set of C++ files that #include all the original
        /// files, the goal being to compile the same code in fewer translation units.
        /// The "unity" files are written to the CompileEnvironment's OutputDirectory.
        /// </summary>
        /// <param name="Target">The target we're building</param>
        /// <param name="CPPFiles">The C++ files to #include.</param>
        /// <param name="CompileEnvironment">The environment that is used to compile the C++ files.</param>
        /// <param name="BaseName">Base name to use for the Unity files</param>
        /// <returns>The "unity" C++ files.</returns>
        public static List <FileItem> GenerateUnityCPPs(
            UEToolChain ToolChain,
            UEBuildTarget Target,
            List <FileItem> CPPFiles,
            CPPEnvironment CompileEnvironment,
            string BaseName
            )
        {
            List <FileItem> NewCPPFiles = new List <FileItem>();

            UEBuildPlatform BuildPlatform = UEBuildPlatform.GetBuildPlatformForCPPTargetPlatform(CompileEnvironment.Config.Platform);

            // Figure out size of all input files combined. We use this to determine whether to use larger unity threshold or not.
            long TotalBytesInCPPFiles = CPPFiles.Sum(F => F.Info.Length);

            // We have an increased threshold for unity file size if, and only if, all files fit into the same unity file. This
            // is beneficial when dealing with PCH files. The default PCH creation limit is X unity files so if we generate < X
            // this could be fairly slow and we'd rather bump the limit a bit to group them all into the same unity file.


            // When enabled, UnrealBuildTool will try to determine source files that you are actively iteratively changing, and break those files
            // out of their unity blobs so that you can compile them as individual translation units, much faster than recompiling the entire
            // unity blob each time.
            bool bUseAdaptiveUnityBuild = BuildConfiguration.bUseAdaptiveUnityBuild && !BuildConfiguration.bStressTestUnity;

            // Optimization only makes sense if PCH files are enabled.
            bool bForceIntoSingleUnityFile = BuildConfiguration.bStressTestUnity || (TotalBytesInCPPFiles < BuildConfiguration.NumIncludedBytesPerUnityCPP * 2 && CompileEnvironment.ShouldUsePCHs());

            // Build the list of unity files.
            List <FileCollection> AllUnityFiles;
            {
                // Sort the incoming file paths alphabetically, so there will be consistency in unity blobs across multiple machines.
                // Note that we're relying on this not only sorting files within each directory, but also the directories
                // themselves, so the whole list of file paths is the same across computers.
                List <FileItem> SortedCPPFiles = CPPFiles.GetRange(0, CPPFiles.Count);
                {
                    // Case-insensitive file path compare, because you never know what is going on with local file systems
                    Comparison <FileItem> FileItemComparer = (FileA, FileB) => { return(FileA.AbsolutePath.ToLowerInvariant().CompareTo(FileB.AbsolutePath.ToLowerInvariant())); };
                    SortedCPPFiles.Sort(FileItemComparer);
                }


                // Figure out whether we REALLY want to use adaptive unity for this module.  If nearly every file in the module appears in the working
                // set, we'll just go ahead and let unity build do its thing.
                if (bUseAdaptiveUnityBuild)
                {
                    int CandidateWorkingSetSourceFileCount = 0;
                    int WorkingSetSourceFileCount          = 0;
                    foreach (FileItem CPPFile in SortedCPPFiles)
                    {
                        // Don't include writable source files into unity blobs
                        if (!CPPFile.Reference.IsUnderDirectory(Target.EngineIntermediateDirectory) &&
                            !CPPFile.Reference.IsUnderDirectory(Target.ProjectIntermediateDirectory))
                        {
                            ++CandidateWorkingSetSourceFileCount;

                            if (UnrealBuildTool.ShouldSourceFileBePartOfWorkingSet(CPPFile.AbsolutePath))
                            {
                                ++WorkingSetSourceFileCount;

                                // Mark this file as part of the working set.  This will be saved into the UBT Makefile so that
                                // the assembler can automatically invalidate the Makefile when the working set changes (allowing this
                                // code to run again, to build up new unity blobs.)
                                SourceFileWorkingSet.Add(CPPFile);
                            }
                        }
                    }

                    if (WorkingSetSourceFileCount >= CandidateWorkingSetSourceFileCount)
                    {
                        // Every single file in the module appears in the working set, so don't bother using adaptive unity for this
                        // module.  Otherwise it would make full builds really slow.
                        bUseAdaptiveUnityBuild = false;
                    }
                }

                UnityFileBuilder CPPUnityFileBuilder          = new UnityFileBuilder(bForceIntoSingleUnityFile ? -1 : BuildConfiguration.NumIncludedBytesPerUnityCPP);
                StringBuilder    AdaptiveUnityBuildInfoString = new StringBuilder();
                foreach (FileItem CPPFile in SortedCPPFiles)
                {
                    if (!bForceIntoSingleUnityFile && CPPFile.AbsolutePath.IndexOf(".GeneratedWrapper.", StringComparison.InvariantCultureIgnoreCase) != -1)
                    {
                        NewCPPFiles.Add(CPPFile);
                    }

                    // When adaptive unity is enabled, go ahead and exclude any source files that we're actively working with
                    if (bUseAdaptiveUnityBuild && SourceFileWorkingSet.Contains(CPPFile))
                    {
                        // Just compile this file normally, not as part of the unity blob
                        NewCPPFiles.Add(CPPFile);

                        // Let the unity file builder know about the file, so that we can retain the existing size of the unity blobs.
                        // This won't actually make the source file part of the unity blob, but it will keep track of how big the
                        // file is so that other existing unity blobs from the same module won't be invalidated.  This prevents much
                        // longer compile times the first time you build after your working file set changes.
                        CPPUnityFileBuilder.AddVirtualFile(CPPFile);

                        string CPPFileName = Path.GetFileName(CPPFile.AbsolutePath);
                        if (AdaptiveUnityBuildInfoString.Length == 0)
                        {
                            AdaptiveUnityBuildInfoString.Append(String.Format("[Adaptive unity build] Excluded from {0} unity file: {1}", BaseName, CPPFileName));
                        }
                        else
                        {
                            AdaptiveUnityBuildInfoString.Append(", " + CPPFileName);
                        }
                    }

                    else
                    {
                        // If adaptive unity build is enabled for this module, add this source file to the set that will invalidate the makefile
                        if (bUseAdaptiveUnityBuild)
                        {
                            CandidateSourceFilesForWorkingSet.Add(CPPFile);
                        }

                        // Compile this file as part of the unity blob
                        CPPUnityFileBuilder.AddFile(CPPFile);

                        // Now that the CPPFile is part of this unity file, we will no longer need to treat it like a root level prerequisite for our
                        // dependency cache, as it is now an "indirect include" from the unity file.  We'll clear out the compile environment
                        // attached to this file.  This prevents us from having to cache all of the indirect includes from these files inside our
                        // dependency cache, which speeds up iterative builds a lot!
                        CPPFile.CachedCPPIncludeInfo = null;
                    }
                }

                if (AdaptiveUnityBuildInfoString.Length > 0)
                {
                    Log.TraceInformation(AdaptiveUnityBuildInfoString.ToString());
                }

                AllUnityFiles = CPPUnityFileBuilder.GetUnityFiles();
            }

            // Create a set of CPP files that combine smaller CPP files into larger compilation units, along with the corresponding
            // actions to compile them.
            int CurrentUnityFileCount = 0;

            foreach (FileCollection UnityFile in AllUnityFiles)
            {
                ++CurrentUnityFileCount;

                StringWriter OutputUnityCPPWriter      = new StringWriter();
                StringWriter OutputUnityCPPWriterExtra = null;

                // add an extra file for UBT to get the #include dependencies from
                if (BuildPlatform.RequiresExtraUnityCPPWriter() == true)
                {
                    OutputUnityCPPWriterExtra = new StringWriter();
                }

                OutputUnityCPPWriter.WriteLine("// This file is automatically generated at compile-time to include some subset of the user-created cpp files.");

                // Add source files to the unity file
                foreach (FileItem CPPFile in UnityFile.Files)
                {
                    OutputUnityCPPWriter.WriteLine("#include \"{0}\"", ToolChain.ConvertPath(CPPFile.AbsolutePath));
                    if (OutputUnityCPPWriterExtra != null)
                    {
                        OutputUnityCPPWriterExtra.WriteLine("#include \"{0}\"", CPPFile.AbsolutePath);
                    }
                }

                // Determine unity file path name
                string UnityCPPFileName;
                if (AllUnityFiles.Count > 1)
                {
                    UnityCPPFileName = string.Format("{0}{1}.{2}_of_{3}.cpp", ModulePrefix, BaseName, CurrentUnityFileCount, AllUnityFiles.Count);
                }
                else
                {
                    UnityCPPFileName = string.Format("{0}{1}.cpp", ModulePrefix, BaseName);
                }
                FileReference UnityCPPFilePath = FileReference.Combine(CompileEnvironment.Config.OutputDirectory, UnityCPPFileName);

                // Write the unity file to the intermediate folder.
                FileItem UnityCPPFile = FileItem.CreateIntermediateTextFile(UnityCPPFilePath, OutputUnityCPPWriter.ToString());
                if (OutputUnityCPPWriterExtra != null)
                {
                    FileItem.CreateIntermediateTextFile(UnityCPPFilePath + ".ex", OutputUnityCPPWriterExtra.ToString());
                }

                UnityCPPFile.RelativeCost = UnityFile.TotalLength;
                NewCPPFiles.Add(UnityCPPFile);

                // Cache information about the unity .cpp dependencies
                // @todo ubtmake urgent: Fails when building remotely for Mac because unity .cpp has an include for a PCH on the REMOTE machine
                UEBuildModuleCPP.CachePCHUsageForModuleSourceFile(CompileEnvironment, UnityCPPFile);
            }

            return(NewCPPFiles);
        }
Exemplo n.º 3
0
		/// <summary>
		/// Given a set of C++ files, generates another set of C++ files that #include all the original
		/// files, the goal being to compile the same code in fewer translation units.
		/// The "unity" files are written to the CompileEnvironment's OutputDirectory.
		/// </summary>
		/// <param name="Target">The target we're building</param>
		/// <param name="CPPFiles">The C++ files to #include.</param>
		/// <param name="CompileEnvironment">The environment that is used to compile the C++ files.</param>
		/// <param name="BaseName">Base name to use for the Unity files</param>
		/// <returns>The "unity" C++ files.</returns>
		public static List<FileItem> GenerateUnityCPPs(
			UEToolChain ToolChain,
			UEBuildTarget Target,
			List<FileItem> CPPFiles,
			CPPEnvironment CompileEnvironment,
			string BaseName
			)
		{
			List<FileItem> NewCPPFiles = new List<FileItem>();

			UEBuildPlatform BuildPlatform = UEBuildPlatform.GetBuildPlatformForCPPTargetPlatform(CompileEnvironment.Config.Target.Platform);

			// Figure out size of all input files combined. We use this to determine whether to use larger unity threshold or not.
			long TotalBytesInCPPFiles = CPPFiles.Sum(F => F.Info.Length);

			// We have an increased threshold for unity file size if, and only if, all files fit into the same unity file. This
			// is beneficial when dealing with PCH files. The default PCH creation limit is X unity files so if we generate < X 
			// this could be fairly slow and we'd rather bump the limit a bit to group them all into the same unity file.


			// When enabled, UnrealBuildTool will try to determine source files that you are actively iteratively changing, and break those files
			// out of their unity blobs so that you can compile them as individual translation units, much faster than recompiling the entire
			// unity blob each time.
			bool bUseAdaptiveUnityBuild = BuildConfiguration.bUseAdaptiveUnityBuild && !BuildConfiguration.bStressTestUnity;

			// Optimization only makes sense if PCH files are enabled.
			bool bForceIntoSingleUnityFile = BuildConfiguration.bStressTestUnity || (TotalBytesInCPPFiles < BuildConfiguration.NumIncludedBytesPerUnityCPP * 2 && CompileEnvironment.ShouldUsePCHs());

			// Build the list of unity files.
			List<FileCollection> AllUnityFiles;
			{
				// Sort the incoming file paths alphabetically, so there will be consistency in unity blobs across multiple machines.
				// Note that we're relying on this not only sorting files within each directory, but also the directories
				// themselves, so the whole list of file paths is the same across computers.
				List<FileItem> SortedCPPFiles = CPPFiles.GetRange(0, CPPFiles.Count);
				{
					// Case-insensitive file path compare, because you never know what is going on with local file systems
					Comparison<FileItem> FileItemComparer = (FileA, FileB) => { return FileA.AbsolutePath.ToLowerInvariant().CompareTo(FileB.AbsolutePath.ToLowerInvariant()); };
					SortedCPPFiles.Sort(FileItemComparer);
				}


				// Figure out whether we REALLY want to use adaptive unity for this module.  If nearly every file in the module appears in the working
				// set, we'll just go ahead and let unity build do its thing.
				if (bUseAdaptiveUnityBuild)
				{
					int CandidateWorkingSetSourceFileCount = 0;
					int WorkingSetSourceFileCount = 0;
					foreach (FileItem CPPFile in SortedCPPFiles)
					{
						// Don't include writable source files into unity blobs
						if (!CPPFile.Reference.IsUnderDirectory(Target.EngineIntermediateDirectory) &&
							!CPPFile.Reference.IsUnderDirectory(Target.ProjectIntermediateDirectory))
						{
							++CandidateWorkingSetSourceFileCount;

							if (UnrealBuildTool.ShouldSourceFileBePartOfWorkingSet(CPPFile.AbsolutePath))
							{
								++WorkingSetSourceFileCount;

								// Mark this file as part of the working set.  This will be saved into the UBT Makefile so that
								// the assembler can automatically invalidate the Makefile when the working set changes (allowing this
								// code to run again, to build up new unity blobs.)
								SourceFileWorkingSet.Add(CPPFile);
							}
						}
					}

					if (WorkingSetSourceFileCount >= CandidateWorkingSetSourceFileCount)
					{
						// Every single file in the module appears in the working set, so don't bother using adaptive unity for this
						// module.  Otherwise it would make full builds really slow.
						bUseAdaptiveUnityBuild = false;
					}
				}

				UnityFileBuilder CPPUnityFileBuilder = new UnityFileBuilder(bForceIntoSingleUnityFile ? -1 : BuildConfiguration.NumIncludedBytesPerUnityCPP);
				StringBuilder AdaptiveUnityBuildInfoString = new StringBuilder();
				foreach (FileItem CPPFile in SortedCPPFiles)
				{
					if (!bForceIntoSingleUnityFile && CPPFile.AbsolutePath.IndexOf(".GeneratedWrapper.", StringComparison.InvariantCultureIgnoreCase) != -1)
					{
						NewCPPFiles.Add(CPPFile);
					}

					// When adaptive unity is enabled, go ahead and exclude any source files that we're actively working with
					if (bUseAdaptiveUnityBuild && SourceFileWorkingSet.Contains(CPPFile))
					{
						// Just compile this file normally, not as part of the unity blob
						NewCPPFiles.Add(CPPFile);

						// Let the unity file builder know about the file, so that we can retain the existing size of the unity blobs.
						// This won't actually make the source file part of the unity blob, but it will keep track of how big the
						// file is so that other existing unity blobs from the same module won't be invalidated.  This prevents much
						// longer compile times the first time you build after your working file set changes.
						CPPUnityFileBuilder.AddVirtualFile(CPPFile);

						string CPPFileName = Path.GetFileName(CPPFile.AbsolutePath);
						if (AdaptiveUnityBuildInfoString.Length == 0)
						{
							AdaptiveUnityBuildInfoString.Append(String.Format("[Adaptive unity build] Excluded from {0} unity file: {1}", BaseName, CPPFileName));
						}
						else
						{
							AdaptiveUnityBuildInfoString.Append(", " + CPPFileName);
						}
					}

					else
					{
						// If adaptive unity build is enabled for this module, add this source file to the set that will invalidate the makefile
						if(bUseAdaptiveUnityBuild)
						{
							CandidateSourceFilesForWorkingSet.Add(CPPFile);
						}

						// Compile this file as part of the unity blob
						CPPUnityFileBuilder.AddFile(CPPFile);

						// Now that the CPPFile is part of this unity file, we will no longer need to treat it like a root level prerequisite for our
						// dependency cache, as it is now an "indirect include" from the unity file.  We'll clear out the compile environment
						// attached to this file.  This prevents us from having to cache all of the indirect includes from these files inside our
						// dependency cache, which speeds up iterative builds a lot!
						CPPFile.CachedCPPIncludeInfo = null;
					}
				}

				if (AdaptiveUnityBuildInfoString.Length > 0)
				{
					Log.TraceInformation(AdaptiveUnityBuildInfoString.ToString());
				}

				AllUnityFiles = CPPUnityFileBuilder.GetUnityFiles();
			}

			string PCHHeaderNameInCode = CPPFiles[0].PCHHeaderNameInCode;
			if (CompileEnvironment.Config.PrecompiledHeaderIncludeFilename != null)
			{
				PCHHeaderNameInCode = ToolChain.ConvertPath(CompileEnvironment.Config.PrecompiledHeaderIncludeFilename.FullName);

				// Generated unity .cpp files always include the PCH using an absolute path, so we need to update
				// our compile environment's PCH header name to use this instead of the text it pulled from the original
				// C++ source files
				CompileEnvironment.Config.PCHHeaderNameInCode = PCHHeaderNameInCode;
			}

			// Create a set of CPP files that combine smaller CPP files into larger compilation units, along with the corresponding 
			// actions to compile them.
			int CurrentUnityFileCount = 0;
			foreach (FileCollection UnityFile in AllUnityFiles)
			{
				++CurrentUnityFileCount;

				StringWriter OutputUnityCPPWriter = new StringWriter();
				StringWriter OutputUnityCPPWriterExtra = null;

				// add an extra file for UBT to get the #include dependencies from
				if (BuildPlatform.RequiresExtraUnityCPPWriter() == true)
				{
					OutputUnityCPPWriterExtra = new StringWriter();
				}

				OutputUnityCPPWriter.WriteLine("// This file is automatically generated at compile-time to include some subset of the user-created cpp files.");

				// Explicitly include the precompiled header first, since Visual C++ expects the first top-level #include to be the header file
				// that was used to create the PCH.
				if (CompileEnvironment.Config.PrecompiledHeaderIncludeFilename != null)
				{
					OutputUnityCPPWriter.WriteLine("#include \"{0}\"", PCHHeaderNameInCode);
					if (OutputUnityCPPWriterExtra != null)
					{
						OutputUnityCPPWriterExtra.WriteLine("#include \"{0}\"", PCHHeaderNameInCode);
					}
				}

				// Add source files to the unity file
				foreach (FileItem CPPFile in UnityFile.Files)
				{
					OutputUnityCPPWriter.WriteLine("#include \"{0}\"", ToolChain.ConvertPath(CPPFile.AbsolutePath));
					if (OutputUnityCPPWriterExtra != null)
					{
						OutputUnityCPPWriterExtra.WriteLine("#include \"{0}\"", CPPFile.AbsolutePath);
					}
				}

				// Determine unity file path name
				string UnityCPPFileName;
				if (AllUnityFiles.Count > 1)
				{
					UnityCPPFileName = string.Format("Module.{0}.{1}_of_{2}.cpp", BaseName, CurrentUnityFileCount, AllUnityFiles.Count);
				}
				else
				{
					UnityCPPFileName = string.Format("Module.{0}.cpp", BaseName);
				}
				FileReference UnityCPPFilePath = FileReference.Combine(CompileEnvironment.Config.OutputDirectory, UnityCPPFileName);

				// Write the unity file to the intermediate folder.
				FileItem UnityCPPFile = FileItem.CreateIntermediateTextFile(UnityCPPFilePath, OutputUnityCPPWriter.ToString());
				if (OutputUnityCPPWriterExtra != null)
				{
					FileItem.CreateIntermediateTextFile(UnityCPPFilePath + ".ex", OutputUnityCPPWriterExtra.ToString());
				}

				UnityCPPFile.RelativeCost = UnityFile.TotalLength;
				UnityCPPFile.PCHHeaderNameInCode = PCHHeaderNameInCode;
				NewCPPFiles.Add(UnityCPPFile);

				// Cache information about the unity .cpp dependencies
				// @todo ubtmake urgent: Fails when building remotely for Mac because unity .cpp has an include for a PCH on the REMOTE machine
				UEBuildModuleCPP.CachePCHUsageForModuleSourceFile(Target, CompileEnvironment, UnityCPPFile);
			}

			return NewCPPFiles;
		}