- Shaved over *half a second* of the best case iterative build times with UnrealBuildTool
- When assembling a build from an existing UBTMakefile, we now load Target information from the makefile instead of from the C# assembly
[CL 2278065 by Mike Fricker in Main branch]
- Fixed confusing exception when a generated code source file was missing
- No longer try compute PCH for a source file when in assembler only mode (PCH is loaded from UBTMakefile)
[CL 2262371 by Mike Fricker in Main branch]
UnrealBuildTool 'Makefiles' allow for very fast iterative builds.
- New BuildConfiguration.xml setting added: "bUseExperimentalFastBuildIteration" (disabled by default)
- Turning this on causes Unreal Build Tool to emit 'UBT Makefiles' for targets when they're built the first time.
- Subsequent builds will load these Makefiles and begin outdatedness checking and build invocation very quickly.
- The caveat is that if source files are added or removed to the project, UBT will need to gather information about those in order for your build to complete successfully.
- Currently, you must run the project file generator after adding/removing source files to tell UBT to re-gather this information.
- Events that can invalidate the 'UBT Makefile':
- Adding/removing .cpp files
- Adding/removing .h files with UObjects
- Adding new UObject types to a file that didn't previously have any
- Changing global build settings (most settings in this file qualify.)
- Changed code that affects how Unreal Header Tool works
- You can force regeneration of the 'UBT Makefile' by passing the '-Gather' argument, or simply regenerating project files
- New command-line parameters added:
- "-Gather": Tells UBT to always perform the gather step (slower but will catch project structural changes)
- "-NoGather": Disables the gather step, unless UBT detects that it must be done. This is the default when bUseExperimentalFastBuildIteration is enabled
- "-GatherOnly": Runs the gather step and saves a UBTMakefile, but doesn't build anything
- "-Assemble": Tells UBT to also assemble build products. This always defaults to enabled
- "-NoAssemble": Tells UBT to skip the assemble step, whether we gathered build products or not
- "-AssembleOnly": Tells UBT to only assemble build products and not to gather, unless UBT determines it must
Other changes:
- UBT now keeps track of which targets it was building in an intermediate file, to help it invalidate cached includes in subsequent runs when the targets are different
- C++ includes are now stored in a class separate from the C++ compile enviroment (for easier serialization)
- The method that UBT uses to find the CoreUObject module timestamp was rewritten
- Various '@todo ubtmake' comments added to tag possible remaining Makefile tasks
- The 'FileItem' class had some member variable comments and code cleaned up, while making it serializable
- Cleaned up the comments and member variables in the "Action" class, while making it serializable
- Some UBT classes are now "serializable". This is because we need to store the data in UBTMakefiles.
- Removed support for Actions to tinker with Stdout and Stderror (was not used for anything)
- Moved PrecompileHeaderEnvironment class to the UEBuildModule.cs source file
- Plugin intermediate include directories are now selected on demand rather than cached early
- Toolchain code for gathering prerequisite headers is now shared in a single function (AddPrerequisiteSourceFile)
- Removed Action.StatusDetailedDescription, was not used for anything
- Removed UEBuildConfiguration.bExcludePlugins, was not used for anything
- Removed ECompilationResult.FailedDueToHeaderChange, was not used for anything
[CL 2254472 by Mike Fricker in Main branch]
#ttp 342622: CRITICAL: Regression: BINARY: PLATFORMERGAME: white square on the screen in cooked version
#codereview robert.manuszewski,ben.marsh
[CL 2240877 by Steve Robb in Main branch]
- Adds experimental super-fast C++ outdated file checking
- This feature is turned off for now as we continue to test and improve it
- You can try it out by enabling "bUseExperimentalFastDependencyScan" option in your BuildConfiguration.xml
- Here is the basic idea:
- We no longer exhaustively scan all includes and build up a big graph every invocation
- Instead, source files whose build products are missing have their includes scanned asynchronously while being compiled
- The flat list of dependent includes for every outdated C++ is saved into a new cache file ("FlatCPPIncludes.bin")
- On the next run, we quickly load that up and "just know" which files to check timestamps on to determine what is out of date
- Lots of "@todo fastubt" comments were added to UnrealBuildTool for potential performance optimizations and further improvements on this feature.
UnrealBuildTool: Determination of which modules have UObjects is now faster
- We now cache which modules have UObjects and load those for the next session
UnrealBuildTool: Module "shared" precompiled header determination is now much faster
- We no longer scan all C++ includes for a module to figure out which "shared" PCH to use
- Instead, we use the module dependencies specified in the module's *.Build.cs file
- For example, if your module depends on "Engine" and "UnrealEd", we choose "UnrealEd"'s shared PCH
Other UBT optimizations:
- Reduced calls to string formatting functions when setting up API definitions for all modules
- Added new performance diagnostics when bPrintPerformanceInfo is enabled in BuildConfiguration.xml
- We no longer check for "external" headers when scanning includes (this code didn't work at all)
- Optimized CleanDirectorySeparators() utility function to avoid string copies
Fixed UnrealBuildTool not saving DependencyCache under a platform-named folder
[CL 2238266 by Mike Fricker in Main branch]
If UBT is building a non-editor configuration it throws an error if the produced binaries has non-redistributable dependencies.
User can avoid throwing error and change it to warning at the end with flag BuildConfiguration.bBreakBuildOnLicenseViolation = false.
In general module to be redistributable it must not be neither Development nor Editor type. This behavior can be overridden though. One have to just assign true or false to IsRedistributableOverride field of ModuleRules in <ModuleName>.Build.cs file.
UBT will not check for the dependencies also if the module being built is non-redistributable (e.g. some internal programs).
#ttp 335755
#codereview Robert.Manuszewski
[CL 2225366 by Jaroslaw Palczynski in Main branch]
- Fixed modules that supply shared PCHs not generating and using their own unique PCH in monolithic builds
- Fixed monolithic builds not detecting that a unique PCH was needed for modules that supply shared PCHs when header file names were different
- Added better verbose debug output to detect problems with shared PCH headers
#codereview robert.manuszewski, ben.marsh
[CL 2220721 by Mike Fricker in Main branch]
