#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]
Newly installed versions of the engine will now attempt to copy the project-agnostic config settings from a previous engine installation. This happens by way of a versioned manifest that copies old versions when the manifest does not exist, or is a different version. This code path is benign for non-installed versions of the engine (or FPaths::ShouldSaveToUserDir() is false).
EditorGameAgnosticSettings and EditorUserSettings ini paths have been renamed to EditorSettings and EditorPerProjectUserSettings respectively to better convey their purpose. In general, most settings should be saved in EditorSettings (project-agnostic) so that they apply regardless of which project is open. We have some way to go migrating existing settings for this to be the case, however.
Some previously per-project configuration files are now project-agnostic (such as Editor.ini, EditorKeyBindings.ini, and EditorLayout.ini)
GEditor->Access...Settings and GEditor->Get...Settings have been removed in favor of direct access of the CDO through GetMutableDefault<> and GetDefault<> respectively. Global config ini filenames that are not set up are now neither loaded nor saved on build machines, to handle the problem of indeterminate state more generically.
This addresses UETOOL-270 (Most editor preferences should be project-agnostic)
[CL 2517558 by Andrew Rodham in Main branch]
Rob asked me to back out GENERATED_*_BODY -> GENERATED_BODY change for now until the "_Validate and _Implementation auto-generation" discussion is over.
#codereview Robert.Manuszewski
[CL 2481343 by Jaroslaw Palczynski in Main branch]
Please note that file comments had no purpose in nearly all cases and just added visual clutter. The two files that had meaningful file comments had their comments moved into the corresponding classes. There are still hundreds of file comments left in other files that will be removed over time.
Also cleaned up some random stuff along the way:
- relative paths to public headers within the same module are no longer necessary (automatically discovered by UBT now)
- header guards are deprecated, use #pragma once instead (all compilers support it now)
- space between multiple template brackets is no longer required (all compilers support >> now)
- NULL to nullptr, OVERRIDE to override
- spelling errors, whitespace, line breaks
[CL 2104067 by Max Preussner in Main branch]
