#lockdown Nick.Penwarden
#rb none
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MAJOR FEATURES + CHANGES
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Change 3209340 on 2016/11/23 by Ben.Marsh
Convert UE4 codebase to an "include what you use" model - where every header just includes the dependencies it needs, rather than every source file including large monolithic headers like Engine.h and UnrealEd.h.
Measured full rebuild times around 2x faster using XGE on Windows, and improvements of 25% or more for incremental builds and full rebuilds on most other platforms.
* Every header now includes everything it needs to compile.
* There's a CoreMinimal.h header that gets you a set of ubiquitous types from Core (eg. FString, FName, TArray, FVector, etc...). Most headers now include this first.
* There's a CoreTypes.h header that sets up primitive UE4 types and build macros (int32, PLATFORM_WIN64, etc...). All headers in Core include this first, as does CoreMinimal.h.
* Every .cpp file includes its matching .h file first.
* This helps validate that each header is including everything it needs to compile.
* No engine code includes a monolithic header such as Engine.h or UnrealEd.h any more.
* You will get a warning if you try to include one of these from the engine. They still exist for compatibility with game projects and do not produce warnings when included there.
* There have only been minor changes to our internal games down to accommodate these changes. The intent is for this to be as seamless as possible.
* No engine code explicitly includes a precompiled header any more.
* We still use PCHs, but they're force-included on the compiler command line by UnrealBuildTool instead. This lets us tune what they contain without breaking any existing include dependencies.
* PCHs are generated by a tool to get a statistical amount of coverage for the source files using it, and I've seeded the new shared PCHs to contain any header included by > 15% of source files.
Tool used to generate this transform is at Engine\Source\Programs\IncludeTool.
[CL 3209342 by Ben Marsh in Main branch]
- The MacToolChain will emit dSYMs and strip executables when the UBT configuration enables bGeneratedSYMFile, just like iOS.
- Symbol stripping requires generating dSYMs to prevent creation of non-debuggable builds whose crash reports would be unresolvable.
- To avoid a dependency on the Private framework CoreSymbolication all symbols from that framework are loaded dynamically & can only be used within programs, not the game or the editor, as CoreSymbolication is incompatible with non-ANSI malloc implementations.
- Added an initial platform-agnostic API for querying debug symbol info, including a generic database format that can be queried on otherwise incompatible platforms.
- Added UnrealAtoS that emulates Apple's atos to resolve symbols using the generic database or the platform API (CoreSymbolication on OS X) which on OS X is used by the editor to gather symbol info for CodeView.
- Added DSymExporter which will export Apple debug symbol data from Mach-O binaries, including the payload within a .dSYM bundle, to the generic format so that the crash report server may one day read the data without needing a Mac to symbolicate reports.
- Initial SymbolDebugger & MinidumpDiagnostics support on OS X.
#codereview michael.trepka, Jaroslaw.Surowiec, lee.clark, peter.sauerbrei
[CL 2466299 by Mark Satterthwaite in Main branch]
