public FileItem CachePCHUsageForCPPFile(FileItem CPPFile, CppIncludePaths IncludePaths, CppPlatform Platform)
{
// @todo ubtmake: We don't really need to scan every file looking for PCH headers, just need one. The rest is just for error checking.
// @todo ubtmake: We don't need all of the direct includes either. We just need the first, unless we want to check for errors.
List <DependencyInclude> DirectIncludeFilenames = GetDirectIncludeDependencies(CPPFile, bOnlyCachedDependencies: false);
if (UnrealBuildTool.bPrintDebugInfo)
{
Log.TraceVerbose("Found direct includes for {0}: {1}", Path.GetFileName(CPPFile.AbsolutePath), string.Join(", ", DirectIncludeFilenames.Select(F => F.IncludeName)));
}
if (DirectIncludeFilenames.Count == 0)
{
return(null);
}
DependencyInclude FirstInclude = DirectIncludeFilenames[0];
// Resolve the PCH header to an absolute path.
// Check NullOrEmpty here because if the file could not be resolved we need to throw an exception
if (FirstInclude.IncludeResolvedNameIfSuccessful != null &&
// ignore any preexisting resolve cache if we are not configured to use it.
bUseIncludeDependencyResolveCache &&
// if we are testing the resolve cache, we force UBT to resolve every time to look for conflicts
!bTestIncludeDependencyResolveCache)
{
CPPFile.PrecompiledHeaderIncludeFilename = FirstInclude.IncludeResolvedNameIfSuccessful;
return(FileItem.GetItemByFileReference(CPPFile.PrecompiledHeaderIncludeFilename));
}
// search the include paths to resolve the file.
string FirstIncludeName = FirstInclude.IncludeName;
UEBuildPlatform BuildPlatform = UEBuildPlatform.GetBuildPlatformForCPPTargetPlatform(Platform);
// convert back from relative to host path if needed
if (!BuildPlatform.UseAbsolutePathsInUnityFiles())
{
FirstIncludeName = RemoteExports.UnconvertPath(FirstIncludeName);
}
FileItem PrecompiledHeaderIncludeFile = CPPHeaders.FindIncludedFile(CPPFile.Reference, FirstIncludeName, IncludePaths);
if (PrecompiledHeaderIncludeFile == null)
{
FirstIncludeName = RemoteExports.UnconvertPath(FirstInclude.IncludeName);
throw new BuildException("The first include statement in source file '{0}' is trying to include the file '{1}' as the precompiled header, but that file could not be located in any of the module's include search paths.", CPPFile.AbsolutePath, FirstIncludeName);
}
IncludeDependencyCache.CacheResolvedIncludeFullPath(CPPFile, 0, PrecompiledHeaderIncludeFile.Reference, bUseIncludeDependencyResolveCache, bTestIncludeDependencyResolveCache);
CPPFile.PrecompiledHeaderIncludeFilename = PrecompiledHeaderIncludeFile.Reference;
return(PrecompiledHeaderIncludeFile);
}
/// <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>
/// <returns>The "unity" C++ files.</returns>
public static List <FileItem> GenerateUnityCPPs(
ReadOnlyTargetRules Target,
List <FileItem> CPPFiles,
CppCompileEnvironment CompileEnvironment,
ISourceFileWorkingSet WorkingSet,
string BaseName,
DirectoryReference IntermediateDirectory
)
{
List <FileItem> NewCPPFiles = new List <FileItem>();
UEBuildPlatform BuildPlatform = UEBuildPlatform.GetBuildPlatformForCPPTargetPlatform(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.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 = 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.Location))
{
++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 : 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 && 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.CachedIncludePaths = null;
}
}
if (AdaptiveUnityBuildInfoString.Length > 0)
{
if (PrintedSettingsForTargets.Add(Target.Name))
{
if (Target.bAdaptiveUnityDisablesPCH)
{
Log.TraceInformation("[Adaptive unity build] Disabling PCH for excluded files. Set bAdaptiveUnityDisablesPCH to false in BuildConfiguration.xml to change this behavior.");
}
if (Target.bAdaptiveUnityDisablesOptimizations)
{
Log.TraceInformation("[Adaptive unity build] Disabling optimizations for excluded files. Set bAdaptiveUnityDisablesOptimizations to false in BuildConfiguration.xml to change this behavior.");
}
}
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();
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)
{
string IncludePath;
if (BuildPlatform.UseAbsolutePathsInUnityFiles())
{
IncludePath = CPPFile.AbsolutePath;
}
else
{
// @todo: MakeRelativeTo does not work with code projects on a different drive than the engine. reverting to old version until we can come
// up with a better solution
IncludePath = RemoteExports.ConvertPath(CPPFile.AbsolutePath).Replace('\\', '/');
}
OutputUnityCPPWriter.WriteLine("#include \"{0}\"", IncludePath);
}
// 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());
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
FileItem FirstCppFile = UnityFile.Files.First();
UEBuildModuleCPP.CachePCHUsageForModuleSourceFile(CompileEnvironment, FirstCppFile);
UnityCPPFile.CachedIncludePaths = FirstCppFile.CachedIncludePaths;
UnityCPPFile.PrecompiledHeaderIncludeFilename = FirstCppFile.PrecompiledHeaderIncludeFilename;
}
return(NewCPPFiles);
}