aclspv uses dialect of OpenCL C.
This page describes the specification of aclspv's target language.

Possible required capabilitties

• Shader

  by default

• Address

  when m_is_logical is off

• VulkanMemoryModel

  when m_is_for_gl is off

Possible required extensions

• SPV_KHR_storage_buffer_storage_class

  by default: when bindable happens

Entry Points

Either with __kernel or kernel, void returning function shall be entry point.

• Execution model will be GLCompute by default.
• Bindable object's bind numbers will be in order of its position, left to right, incremented.
• Arguments which is not pointer or an array will be merged into one push constant with 32-bit aligned.

Address Space Qualifiers

__global

• Has to be pointer and maps to StorageBuffer in Vulkan.
• Bindable
• Only for entry points
• Scope will be modular
• Must be used as an argument of Entry Points.
• 32-bit alignment is adviced.
• always parsed as u32* (you will not care)

__local

• Has to be constant array and maps to Workgroup in Vulkan.
• Not binded by host.
• Its size could be specified. See aclspv_set(set).
• Scope will be modular
• 32-bit alignment is adviced.
• always parsed as u32[(COUNT + 3) / 4] (you will not care)

__constant

• Maps to Uniform in Vulkan when used as an argument of Entry Points.
  • Bindable
  • Scope will be modular
  • Only for entry points
  • 128-bit alignment is adviced.
  • always parsed as vec4* (you will not care)
• Maps to constant literals in other use cases.

Attributes

Some compiler attributes are available for vulkan-specific behaviours.
Many will be annotation attribute so seem as __attribute__((annotate("<here>")))

aclspv_specid(specid)

Make constant value modifiable on vulkan pipeline.
See shader stage create info

• if specid is 0xFFFFFFFF, it will be seen undefined.
• Maps to OpSpecConstant with id of specid
• Result type must be scalar Integer or Floating point type.
• Follows the first specified value & data type.
• Default value must be specified on first use.
• Ignores the initialising value when specid is found.
• Must be specified on use. E.g:
  • Setting a size of an constant array
  • Initialising a non-constant variable
• Specifying on following condition will be ignored
  • Enumerators
  • __constant variable
  • Constant literals

aclspv_set(set)

Specifies the descriptor sets of bindable object.

• Could be used on bindable objects.
• set must be a 32-bit integer as decimal

aclspv_wrkgroup_size(x, y, z)

Specifies the entry point's workgroup size.

• Has reqd_work_group_size(x, y, z) as alternatives.
  
• x, y, z must be a 32-bit integer as decimal literal.
• This attribute could be ignored when its execution model is not either Kernel or GLCompute.

aclspv_execmodel(model)

Specifies the execution model of the entry point.
Solution for other than GLCompute, Fragment, Vertex will not implicitly be developed.
Solution for other than Fragment, Vertex will not be actively developed.

• model must be a 32-bit integer as decimal literal.
• Possible inputs are defined as enum SpvExecutionModel_ on spirv-header.
• When not specified, defaults to GLCompute.

aclspv_storage_class(class)

Specifies the storage class for the target variable.

• class must be a 32-bit integer as decimal literal.
• Possible inputs are defined as enum SpvStorageClass_ on spirv-header.

aclspv_location(location)

Specifies the location of input or output

• When not specified, every input our output's location will be 0.

Restriction

Some statements / extensions may not be planned to be supported for now.

• VK_KHR_relaxed_block_layout behaviour (free alignment)
• Non plain-old-data types
• OpenCL memory model
• Simple memory model