SPV_KHR_physical_storage_buffer

Add new terms to section 2.2.2 Types:

Physical Pointer Type: A pointer type is a physical pointer type if the storage class of the type pointed to uses physical addressing according to the addressing model.

Logical Pointer Type: A pointer type is a logical pointer type if it is not a physical pointer type.

Modify the following definitions:

Concrete Type: A numerical scalar, vector, matrix type, or physical pointer type, or any aggregate containing only these types.

Abstract Type: An OpTypeVoid or OpTypeBool, or logical pointer type, or any aggregate type containing any of these.

Modify the definition of Memory Object Declaration:

Memory Object Declaration: An OpVariable, or an OpFunctionParameter of pointer type, or the contents of an OpVariable that holds a pointer to PhysicalStorageBuffer storage class or holds an array of such pointers.

Modify the first part of the definition of Variable pointer from:

Variable pointer: A pointer that results from one of the following instructions: …​

to:

Variable pointer: A pointer of logical pointer type that results from one of the following instructions: …​

Modify section 2.16.1. Universal Validation Rules:

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Add the following rules:

If the addressing model is not PhysicalStorageBuffer64, then the PhysicalStorageBuffer storage class must not be used.

Add PhysicalStorageBuffer to the list of storage classes that support atomic access.

OpVariable must not use a storage class of PhysicalStorageBuffer.

If an OpVariable's pointee type is a pointer (or array of pointers) in PhysicalStorageBuffer storage class, then the variable must be decorated with exactly one of AliasedPointer or RestrictPointer.

If an OpFunctionParameter is a pointer (or array of pointers) in PhysicalStorageBuffer storage class, then the function parameter must be decorated with exactly one of Aliased or Restrict.

If an OpFunctionParameter is a pointer (or array of pointers) and its pointee type is a pointer in PhysicalStorageBuffer storage class, then the function parameter must be decorated with exactly one of AliasedPointer or RestrictPointer.

Any pointer value whose storage class is PhysicalStorageBuffer and that points to a matrix or an array of matrices or a row or element of a matrix must be the result of an OpAccessChain or OpPtrAccessChain instruction whose base is a structure type (or recursively must be the result of a sequence of only access chains from a structure to the final value). Such a pointer must only be used as the Pointer operand to OpLoad or OpStore.

Modify section 2.16.2. Validation Rules for Shader Capabilities:

Add PhysicalStorageBuffer to the list of storage classes in which composite objects must be explicitly laid out.

Add PhysicalStorageBuffer to the list of storage classes to which the result of a FPRoundingMode-decorated conversion instruction can be stored.

Modify section 2.18.2. Aliasing:

Replace the paragraph about Simple, GLSL, and VulkanKHR memory models:

The Simple, GLSL, and VulkanKHR memory models can assume that aliasing is generally not present between the memory object declarations. Specifically, the consumer is free to assume aliasing is not present between memory object declarations, unless the memory object declarations explicitly indicate they alias.

Aliasing is indicated by applying the Aliased decoration to a memory object declaration’s <id>, for OpVariable and OpFunctionParameter <id>s. Applying Restrict is allowed, but has no effect.

For variables holding PhysicalStorageBuffer pointers, applying the AliasedPointer decoration on the OpVariable <id> indicates that the PhysicalStorageBuffer pointers are potentially aliased. Applying RestrictPointer is allowed, but has no effect. Variables holding PhysicalStorageBuffer pointers must be decorated as either AliasedPointer or RestrictPointer.

Only those memory object declarations decorated with Aliased or AliasedPointer may alias each other.

Modify the Aliasing table in section 2.18.2:

Add a new row for PhysicalStorageBuffer that is a copy of StorageBuffer. Add PhysicalStorageBuffer everywhere StorageBuffer is used in the "Second Storage Classes" column.

Add to the description of the Aliasing table:

For the PhysicalStorageBuffer storage class, OpVariable is understood to mean the PhysicalStorageBuffer pointer value(s) stored in the variable. An Aliased PhysicalStorageBuffer pointer stored in a Function variable can potentially alias with other variables in the same function, or with global variables or function parameters.

Add PhysicalStorageBuffer to the list of storage classes synchronized by UniformMemory.

Add to the description of Aligned:

Valid values are defined by the execution environment.

Modify Section 3.31, "Capability", adding these rows to the Capability table:

Add PhysicalStorageBuffer to the list of storage classes for the StorageBuffer16BitAccess, UniformAndStorageBuffer16BitAccess, StorageBuffer8BitAccess, and UniformAndStorageBuffer8BitAccess capabilities.

Modify the OpTypeForwardPointer, OpConvertUToPtr, OpConvertPtrToU, and OpPtrAccessChain instructions to add PhysicalStorageBufferAddresses to their capability lists.

Modify OpConvertUToPtr to require that the result type must be a physical pointer type.

Modify OpConvertPtrToU to require that the Pointer operand must have a physical pointer type.

Modify OpBitcast to allow vector conversions to/from pointers, by changing this existing rule:

to instead say: