- Merged in Microsoft's Unreal Build Tool changes for VS 2015 support, and Universal App Platform support
- VS 2015 support is disabled by default (the engine is not yet compiling with VS 2015)
- Use the new '-2015' option when generating project files to enable VS 2015 support
- Windows SDK 8.1 is used by default. To use Windows SDK 10, enable WindowsPlatform.bUseWindowsSDK10
- UAP support is disabled (not supported yet, work in progress.) Use WinUAPPlatform.bEnableUAPSupport to enable it.
- Various loose ends still remain (search for "@todo UAP" in Unreal Build Tool code)
[CL 2537920 by Mike Fricker in Main branch]
These changes allow UE4 to compile and run (in Debug) on Clang 3.7 alpha (r231657 only!)
- Disabled editor source file discovery (crashes with Clang currently)
- Disabled FThreadIdleStats in UnrealHeaderTool with Clang on Windows (causes link errors due to inlining bugs with Clang and DLL imports)
- Use MSVC linker by default, even when compiling with Clang (can be tweaked with bAllowClangLinker)
- Enabled shadow variable warnings on Windows with Clang
- Limited max size of reflection code source files (Clang on Windows crashes with huge source files)
- Fixed UE4 deprecation warnings not showing up when using Clang on Windows
- Make sure initialization list order only triggers a warning on Clang for Windows
Other changes:
- Fixed issues with pushed pragmas not getting popped (PRAGMA_ENABLE_DEPRECATION_WARNINGS)
- Removed EMIT_DEPRECATED_WARNING_MESSAGE, wasn't used
- Fixed various third party library includes not being treated as system headers (prevents compiler warnings)
To test Clang on Windows (beta!!):
- Get latest UE4 main branch (4.9)
- Install LLVM+Clang for Windows version r231657. It's a quick install, you don't need to compile anything yourself.
- Open UEBuildWindows.cs, and change bCompileWithClang to true. Be careful not to check that in. We'll probably make this config-driven later, after the Clang toolchain gets more mature.
- Switch to Debug Editor configuration. (See below for more info.)
- Rebuild the game or engine
Notes:
- You must use Clang r231657 (3.7.0 alpha). There are no other releases that I've found that are able to compile UE4 successfully. Most of the newer releases crash during compiling, and older releases aren't able to digest Windows header files well enough.
- Compiling in Development currently will not work due to bugs with Clangs handling of inlining and DLL exports. Monolithic builds should work, though.
- Occasionally you may see runtime crashes (stack overflows or access violations) when running UE4 compiled with Clang on Windows. These may very well be bugs in Clang (remember, we're using an alpha release of Clang 3.7.0.) Unfortunately without better debugger support, it can be difficult to workaround these
- When debugging, you will only have functions and line numbers, no variables or parameters. Clang only has preliminary support for Microsoft's PDB format currently.
XGE is fully supported with Clang on Windows. Best case rebuild times I've seen are 3.5 minutes in Debug.
- Shared PCHs aren't supported yet (similar to on Mac and Linux), so iterative compile times may be slower compared to Visual C++. However the Clang compiler is actually quite fast for rebuilds, probably because of missing debug info though.
- There may be some compiler warnings that are different between Mac/Linux and Windows. We haven't done a line-by-line comparison yet.
- Build products and executables for Clang and VC++ overlap on disk. So you have to rebuild to switch back and forth. Sorry.
- Clang on Windows has a few bugs that we've had to work around. You might see some strange things from time to time. Every new release of Clang has different behavior on Windows.
- We still use the VC++ Linker, even when compiling using Clang. The new Clang linker (lld.exe) can be enabled with bAllowClangLinker but it will crash when linking some modules. It also doesn't produce usable debug symbols by Visual Studio (yet).
#codereview mikolaj.sieluzycki
[CL 2532260 by Mike Fricker in Main branch]
Pathalogical case in the ExtendingTheEditor sample was using a PCH name of: D:\\BuildFarm\\buildmachine_++depot+UE4\\Samples\\Sandbox\\ExtendingTheEditor\\Plugins\\DemoEditorExtensions\\Intermediate\\Build\\Win64\\ExtendingTheEditor\\Debug\\DemoEditorExtensionsRuntime\\PCH.DemoEditorExtensionsRuntime.DemoEditorExtensionsRuntimePrivatePCH.h.cpp
[CL 2523558 by Ben Marsh in Main branch]
- Experimenting with disabling this to see if we notice any drawbacks (seems fine after a few days of testing)
[CL 2517690 by Mike Fricker in Main branch]
Modifies postprocessing pipeline so that distortion is done on buffers scaled by ScreenPercentage. Scaling up ScreenPercentage will now have a bigger effect on aliasing in the HMD.
Modifies headtracking to be driven by VBLank events rather than the render thread. Reduces tracking loss.
#codereview Nick.Whiting,JJ.Hoesing
[CL 2505935 by Marcus Wassmer in Main branch]
- The entire editor can now be compiled using Clang on Windows. It also runs (as long as you use the MSVC linker.)
- Use UEBuildWindows.bCompileWithClang=true to help test Clang support
- Most UE4 programs can now be compiled using Clang on Windows, and linked using the Clang linker on Windows
- Many C++ syntax fixes to resolve Clang errors and warnings when on Windows
- Clang on Windows now supports PCH files properly (but not "shared" PCHs, yet.)
- Hacked the DirectX XAudio2 headers slightly to work around a macro pasting bug in Clang
[CL 2494439 by Mike Fricker in Main branch]
* Import libraries are added to the build manifest whenever precompiling modules
* UHT now just generates headers to the project directory, and headers aren't included in the engine distribution. UHT was generating them anyway, just not writing them.
* Plugins binaries now just use UE4Game prefix in Rocket (since that's where they're built from), rather than using a special name.
* Platform-specific plugins are not explicitly excluded from builds - will be stripped out by directory instead
* XMPP is not manually excluded from Rocket builds.
* Removed BuildingRocket() function.
[CL 2487163 by Ben Marsh in Main branch]
Move code which detects the VS2012 toolchain for Windows. We don't support it, and UAT calling into it can cause attempts to stage the wrong DLLs for BP-only games. Leave the plumbing around for when we introduce VS2015 support. (UE-9991)
[CL 2450053 by Matthew Griffin in Main branch]
XP support was not able to be set from Bootstrap packaged game. Which meant the subsystem version wasnt valid on xp for this.
[CL 2430072 by Terence Burns in Main branch]
