Bug 212444

Summary: New build system causing full WebCore recompiles
Product: WebKit Reporter: Kenneth Russell <kbr>
Component: Tools / TestsAssignee: Keith Rollin <krollin>
Status: RESOLVED DUPLICATE    
Severity: Major CC: dino, krollin, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 199212, 209890, 212428, 212530, 212623    
Bug Blocks:    
Attachments:
Description Flags
zip archive of build output none

Kenneth Russell
Reported 2020-05-27 16:55:21 PDT
Created attachment 400403 [details] zip archive of build output After the switch to the new build system, touching a single .cc file in for example Source/ThirdParty/ANGLE and running: ./Tools/Scripts/build-webkit --release --ios-simulator > build-log.txt 2>&1 seems to cause some timestamp in JavaScriptCore to be modified, causing headers to be regenerated, and a lot of WebCore to be rebuilt. Attached is the (aborted) output after touching Source/ThirdParty/ANGLE/src/libANGLE/formatutils.cpp and running that command. (WebKit was completely built in this configuration before touching that file and attempting a rebuild.) This drastically increases incremental build times and basically destroys our ability to contribute to WebKit. Can this regression please be investigated?
Attachments
zip archive of build output (182.46 KB, application/zip)
2020-05-27 16:55 PDT, Kenneth Russell 		no flags
Details
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Radar WebKit Bug Importer
Comment 1 2020-05-27 16:55:41 PDT
<rdar://problem/63696405>
Kenneth Russell
Comment 2 2020-05-27 17:29:01 PDT
Note: I might have broken something in Bug 212428.
Kenneth Russell
Comment 3 2020-05-27 19:16:38 PDT
Undoing my change to WebKit.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings from Bug 212428, touching a file in Source/ThirdParty/ANGLE and running: ./Tools/Scripts/build-webkit --debug --ios-simulator still does a huge rebuild of lots of JavaScriptCore, WebCore, and WebKit. Incremental builds aren't working any more in WebKit.
Kenneth Russell
Comment 4 2020-05-29 18:06:56 PDT
The switch to XCBuild was reverted in Bug 212530 so reducing the priority to P2, Major. Keith, may I assign this to you to follow up on later? I can help fix ANGLE so that it doesn't regenerate its headers all the time (originally fixed in Bug 199212, but seems it will need a new solution that doesn't generate a timestamp but is instead based on the file's contents).
Keith Rollin
Comment 5 2020-10-06 02:51:35 PDT
*** This bug has been marked as a duplicate of bug 217371 ***
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