Live++ reads object files at startup for game modules, and assigns unique ids to each compiland (used to disambiguate static variables). When compiling the patch, these compilands are modified to reference a unique id for the unity blob, causing the variables to be reconstructed.
Solution is to generate a JSON file to each output directory containing object files containing the mapping, and to use that to assign compiland ids at startup.
#rb none
#jira UE-74036
[CL 6455253 by Ben Marsh in 4.22 branch]
Allows fast iteration of C++ changes without restarting the application. To use, select the "Live Coding (Experimental)" mode from the drop down menu next to the editor's compile button, or type "LiveCoding" into the console for a monolithic build. Press Ctrl+Alt+F11 to find changes and compile.
Changes vs standalone Live++ version:
* UBT is used to execute builds. This allows standard UE4 adaptive unity mode, allows us to reuse object files when we do regular builds, supports using any build executor allowed by UBT (XGE, SNDBS, etc..).
* Adding new source files is supported.
* Custom visualizer for FNames is supported via a weakly linked symbol in a static library (Engine/Extras/NatvisHelpers).
* Settings are exposed in the editor's project settings dialog.
* Standalone application has been rewritten as a Slate app ("LiveCodingConsole"). There is an additional option to start the program as hidden, where it will not be visible until Ctrl+Alt+F11 is hit. Similarly, closing the window will hide it instead of closing the application.
* Does not require a standalone licensed version of Live++.
Known issues:
* Does not currently support class layout changes / object reinstancing
#rb none
#fyi Marc.Audy, Stefan.Boberg, Nick.Penwarden
#jira
[CL 5304722 by Ben Marsh in 4.22 branch]
