Bug 189326

Summary: [WHLSL] The interpreter should evaluate arguments right-to-left
Product: WebKit Reporter: Thomas Denney <tdenney>
Component: WebGPUAssignee: Thomas Denney <tdenney>
Status: RESOLVED DUPLICATE    
Severity: Normal CC: achristensen, dino, jonlee, mmaxfield, tdenney, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 189360    
Bug Blocks: 176199, 188402, 189202    
Attachments:
Description Flags
Patch
none
Patch
none
WIP none

Thomas Denney
Reported 2018-09-05 16:17:52 PDT
In order to be consistent with C, the arguments of function calls should be evaluated right-to-left. C doesn’t define an evaluation order for operators (like +) but because we treat them as “native functions” we should strictly evaluate them right-to-left.
Attachments
Patch (3.40 KB, patch)
2018-09-05 16:21 PDT, Thomas Denney 		no flags
DetailsFormatted DiffDiff
Patch (3.75 KB, patch)
2018-09-05 17:12 PDT, Thomas Denney 		no flags
DetailsFormatted DiffDiff
WIP (4.83 KB, patch)
2018-09-06 11:24 PDT, Thomas Denney 		no flags
DetailsFormatted DiffDiff
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.
Thomas Denney
Comment 1 2018-09-05 16:21:52 PDT
Created attachment 348978 [details] Patch
Thomas Denney
Comment 2 2018-09-05 17:12:43 PDT
Created attachment 348982 [details] Patch
Alex Christensen
Comment 3 2018-09-05 18:20:20 PDT
Comment on attachment 348982 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=348982&action=review This order is not determined in C or C++, but it is commonly evaluated in a consistent order for reasons. See https://en.cppreference.com/w/c/language/eval_order I think it would be great if WHLSL had a defined order, but don't claim it's to be consistent with C. > Tools/ChangeLog:8 > + The behavior of the interpreter now matches the behavior of the compiler What compiler are you talking about? It's possible the behavior of that compiler is unspecified but it happens to be right-to-left in all the cases you've checked.
Myles C. Maxfield
Comment 4 2018-09-05 19:12:39 PDT
Comment on attachment 348982 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=348982&action=review > Tools/WebGPUShadingLanguageRI/Test.js:7637 > + int foo() { return *bar(10) + *bar(20); } > + > + thread int* bar(int value) > + { > + int x = value; > + return &x; > + } I don't think we should commit a test that is fundamentally wrong.
Thomas Denney
Comment 5 2018-09-05 19:26:10 PDT
(In reply to Alex Christensen from comment #3) > Comment on attachment 348982 [details] > Patch > > View in context: > https://bugs.webkit.org/attachment.cgi?id=348982&action=review > > This order is not determined in C or C++, but it is commonly evaluated in a > consistent order for reasons. See > https://en.cppreference.com/w/c/language/eval_order > I think it would be great if WHLSL had a defined order, but don't claim it's > to be consistent with C. > > > Tools/ChangeLog:8 > > + The behavior of the interpreter now matches the behavior of the compiler > > What compiler are you talking about? It's possible the behavior of that > compiler is unspecified but it happens to be right-to-left in all the cases > you've checked. The WHLSL -> Metal code generation generates code so that the arguments are explicitly evaluated right-to-left before the function call and are then passed separately.
Thomas Denney
Comment 6 2018-09-06 11:24:10 PDT
Created attachment 349046 [details] WIP
Thomas Denney
Comment 7 2018-09-10 16:22:43 PDT
The most recent patch of https://bugs.webkit.org/show_bug.cgi?id=188641 resolves this, and it would only be a two line change to that patch to resolve this bug. *** This bug has been marked as a duplicate of bug 188641 ***
Radar WebKit Bug Importer
Comment 8 2018-09-12 18:41:25 PDT
<rdar://problem/44402790>
Myles C. Maxfield
Comment 9 2018-10-13 14:35:40 PDT
Migrated to https://github.com/gpuweb/WHLSL/issues/42
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