Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 98c11ccb36a75ad6e0dc02922a88b8b767842272
https://github.com/WebKit/WebKit/commit/98c11ccb36a75ad6e0dc02922a88b8b767842272
Author: Tadeu Zagallo <tzaga...@apple.com>
Date: 2023-06-01 (Thu, 01 Jun 2023)
Changed paths:
M Source/WebGPU/WGSL/AST/ASTExpression.h
M Source/WebGPU/WGSL/AST/ASTIdentityExpression.h
M Source/WebGPU/WGSL/GlobalVariableRewriter.cpp
M Source/WebGPU/WGSL/Metal/MetalFunctionWriter.cpp
A Source/WebGPU/WGSL/tests/valid/type-promotion.wgsl
Log Message:
-----------
[WGSL] Fix serialization of promoted types
https://bugs.webkit.org/show_bug.cgi?id=257558
rdar://110075846
Reviewed by Myles C. Maxfield.
The problem happens when we have an array of vectors of abstract int, which
later
gets promoted to something other than i32. This can only happen through consts
or
calls with an immediate value. The two simplest examples are:
let x : array<vec2<f32>> = array(vec2(0))
f(array(vec2(0)), where f expects array<vec2<f32>>
In both cases, the issues is the same. The type inferred for the expression
`array(vec2(0))`
is `array<vec2<abstract-int>>`. However, later we discover this value will be
used
as `array<vec2<f32>>`, which is a valid conversion (and currently supported by
our
type checker). The problem occurs at serialization time, since we don't update
the
inferred type of the nested expression `vec2(0)`, so we generate a vector or
ints.
This gets further complicated when we have a single constant used by two
functions,
and the constant gets promoted to two different types. e.g.:
const a = array(vec2(0));
let x: array<vec2<u32>> = a;
let y: array<vec2<f32>> = a;
To solve this problem, we duplicate the constants' declaration at the time of
use,
and make sure the new instance has the correct type. Effectively transforming
the
above code into:
const a1 : array<vec2<u32>> = array(vec2(0));
let x: array<vec2<u32>> = a1;
const a2 : array<vec2<f32>> = array(vec2(0));
let y: array<vec2<f32>> = a2;
Further, at code generation time, we handle the special case of arrays: this
problem
can only occur when we have an abstract compound type inside an array
constructor.
So, in the codegen, whenever we see an array constructor, we pass the
information
down that it's arguments should have the same type as the array element type.
* Source/WebGPU/WGSL/AST/ASTExpression.h:
* Source/WebGPU/WGSL/AST/ASTIdentityExpression.h:
* Source/WebGPU/WGSL/GlobalVariableRewriter.cpp:
(WGSL::RewriteGlobalVariables::visit):
(WGSL::RewriteGlobalVariables::insertLocalDefinitions):
(WGSL::RewriteGlobalVariables::readVariable):
(WGSL::RewriteGlobalVariables::insertBeforeCurrentStatement):
(WGSL::RewriteGlobalVariables::read): Deleted.
* Source/WebGPU/WGSL/Metal/MetalFunctionWriter.cpp:
(WGSL::Metal::FunctionDefinitionWriter::serializeVariable):
(WGSL::Metal::FunctionDefinitionWriter::visit):
(WGSL::Metal::visitArguments):
* Source/WebGPU/WGSL/tests/valid/type-promotion.wgsl: Added.
Canonical link: https://commits.webkit.org/264787@main
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