tree 4364c4008dd0d12be5aeaa206d2aa4685e0a065f
parent fa4ac89ea1243bcacb8f89609ba8e27a0c8b0dd4
author mmaxfield@apple.com <mmaxfield@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1560404308 +0000
committer mmaxfield@apple.com <mmaxfield@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1560404308 +0000

[WHLSL] Implement array references
https://bugs.webkit.org/show_bug.cgi?id=198163

Reviewed by Saam Barati.

Source/WebCore:

The compiler automatically generates anders for every array reference. Luckily, the infrastructure
to generate those anders and emit Metal code to represent them already exists in the compiler.
There are two pieces remaining (which this patch implements):

1. The JavaScript compiler has a behavior where anders that are called with an array reference
   as an argument don't wrap the argument in a MakePointerExpression. This is because the array
   reference is already a reference type, so it's silly to operate on a pointer to a reference.
   This patch implements this by teaching the type checker about which types should be passed
   to the ander call, and by actually constructing those types in the property resolver.
   The property resolver does this by placing the logic to construct an ander argument in a
   single function which also has logic to save the argument in a temporary if the thread ander
   will be called. The semantics about which functions are called in which situations are not
   changed; instead, we just simply don't wrap array references with MakePointerExpressions.

2. Creating a bind group from the WebGPU API has to retain information about buffer lengths for
   each buffer so the shader can properly perform bounds checks. This can be broken down into a
   few pieces:
   - Creating a bind group layout has to assign extra id indexes for each buffer which will be
     filled in to represent the buffer's length
   - Creating the bind group itself needs to fill in the buffer length into the Metal argument
     buffer
   - The shader compiler needs to emit code at the beginning of entry point to find the buffer
     lengths and pack them together into the array reference (array references correspond to
     a Metal struct with two fields: a pointer and a length).

This patch doesn't actually implement bounds checks themselves; it just hooks up the buffer
lengths so https://bugs.webkit.org/show_bug.cgi?id=198600 can implement it.

The shader compiler's API is modified to allow for this extra buffer length information to be
passed in from the WebGPU implementation.

Unfortunately, I don't think I could split this patch up into two pieces because both are
required to test the compiler with buffers.

Tests: webgpu/whlsl-buffer-fragment.html
       webgpu/whlsl-buffer-vertex.html

* Modules/webgpu/WHLSL/AST/WHLSLPropertyAccessExpression.h:
(WebCore::WHLSL::AST::PropertyAccessExpression::baseReference):
* Modules/webgpu/WHLSL/AST/WHLSLResourceSemantic.cpp:
(WebCore::WHLSL::AST::ResourceSemantic::isAcceptableType const): Arrays can't be resources
because the compiler has no way of guaranteeing if the resource is long enough to hold the
array at compile time.
* Modules/webgpu/WHLSL/Metal/WHLSLEntryPointScaffolding.cpp:
(WebCore::WHLSL::Metal::EntryPointScaffolding::EntryPointScaffolding): Generate an extra
variable name to represent the buffer length. Only do it for resources which have lengths.
(WebCore::WHLSL::Metal::EntryPointScaffolding::resourceHelperTypes):
(WebCore::WHLSL::Metal::EntryPointScaffolding::unpackResourcesAndNamedBuiltIns): Perform
the appropriate math to turn byte lengths into element counts and store the element count
in the array reference.
* Modules/webgpu/WHLSL/Metal/WHLSLEntryPointScaffolding.h:
* Modules/webgpu/WHLSL/WHLSLChecker.cpp:
(WebCore::WHLSL::resolveWithOperatorAnderIndexer): Refactor.
(WebCore::WHLSL::resolveWithOperatorLength): Ditto.
(WebCore::WHLSL::resolveWithReferenceComparator): Ditto.
(WebCore::WHLSL::resolveByInstantiation): Ditto.
(WebCore::WHLSL::argumentTypeForAndOverload): Given an ander, what should the type of the
argument be?
(WebCore::WHLSL::Checker::finishVisiting): Call argumentTypeForAndOverload(). Also, if
we couldn't find an ander, try automatically generating it, the same way that function
calls do. (This is how array references get their anders.)
(WebCore::WHLSL::Checker::visit):
* Modules/webgpu/WHLSL/WHLSLPipelineDescriptor.h: New WHLSL API to provide the length
information.
* Modules/webgpu/WHLSL/WHLSLPropertyResolver.cpp:
(WebCore::WHLSL::PropertyResolver::visit): SimplifyRightValue() can't fail any more.
(WebCore::WHLSL::wrapAnderCallArgument): If the ander argument should be wrapped in a
MakePointer or a MakeArrayReference, do that. Also, if the ander is a thread ander, save
the argument in a local variable and use that.
(WebCore::WHLSL::anderCallArgument): The equivalent of argumentTypeForAndOverload().
(WebCore::WHLSL::setterCall): Call anderCallArgument().
(WebCore::WHLSL::getterCall): Ditto.
(WebCore::WHLSL::modify): We used to have special-case code for handling pointer-to-argument
values as distinct from just the argument values themselves. However, emitting
chains of &* operators is valid and won't even make it through the Metal code generator
after https://bugs.webkit.org/show_bug.cgi?id=198600 is fixed. So, in order to simplify
wrapAnderCallArgument(), don't special case these values and just create &* chains instead.
(WebCore::WHLSL::PropertyResolver::simplifyRightValue):
(WebCore::WHLSL::LeftValueSimplifier::finishVisiting): Call anderCallArgument().
* Modules/webgpu/WHLSL/WHLSLSemanticMatcher.cpp: Update to support the new compiler API.
(WebCore::WHLSL::matchMode):
(WebCore::WHLSL::matchResources):
* Modules/webgpu/WebGPUBindGroupDescriptor.cpp: Ditto.
(WebCore::WebGPUBindGroupDescriptor::tryCreateGPUBindGroupDescriptor const):
* platform/graphics/gpu/GPUBindGroupLayout.h: Add some internal implementation data inside
the bindings object. Use a Variant to differentiate between the various bindings types, and
put the extra length field on just those members of the variant that represent buffers.
* platform/graphics/gpu/cocoa/GPUBindGroupLayoutMetal.mm: Update to support the new compiler API.
(WebCore::argumentDescriptor):
(WebCore::GPUBindGroupLayout::tryCreate):
* platform/graphics/gpu/cocoa/GPUBindGroupMetal.mm: Ditto.
(WebCore::setBufferOnEncoder):
(WebCore::GPUBindGroup::tryCreate):
* platform/graphics/gpu/cocoa/GPURenderPipelineMetal.mm: Ditto.
(WebCore::convertBindingType):
(WebCore::convertLayout):

LayoutTests:

* webgpu/buffer-resource-triangles-expected.html: Deleted. This test doens't make any sense and triggers
Metal to read out-of-bounds of a vertex buffer.
* webgpu/buffer-resource-triangles.html: Deleted.
* webgpu/whlsl-buffer-fragment-expected.html: Added.
* webgpu/whlsl-buffer-fragment.html: Added.
* webgpu/whlsl-buffer-vertex-expected.html: Added.
* webgpu/whlsl-buffer-vertex.html: Added.
* webgpu/whlsl-dont-crash-parsing-enum.html:
* webgpu/whlsl.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@246394 268f45cc-cd09-0410-ab3c-d52691b4dbfc