'dlti' Dialect

The Data Layout and Target Information (DLTI) dialect is intended to hold attributes and other components pertaining to descriptions of in-memory data layout and compilation targets.

Attributes ¶

DataLayoutEntryAttr ¶

An attribute to represent an entry of a data layout specification.

A data layout entry attribute is a key-value pair where the key is a type or an identifier and the value is another attribute. These entries form a data layout specification.

Parameters: ¶

DataLayoutSpecAttr ¶

An attribute to represent a data layout specification.

A data layout specification is a list of entries that specify (partial) data layout information. It is expected to be attached to operations that serve as scopes for data layout requests.

Parameters: ¶

MapAttr ¶

A mapping of DLTI-information by way of key-value pairs

A Data Layout and Target Information map is a list of entries effectively encoding a dictionary, mapping DLTI-related keys to DLTI-related values.

This attribute’s main purpose is to facilate querying IR for arbitrary key-value associations that encode DLTI. Facility functions exist to perform recursive lookups on nested DLTI-map/query interface-implementing attributes.

Consider the following flat encoding of a single-key dictionary

#dlti.map<"CPU::cache::L1::size_in_bytes" = 65536 : i32>>

versus nested maps, which make it possible to obtain sub-dictionaries of related information (with the following example making use of other attributes that also implement the DLTIQueryInterface):

#dlti.target_system_spec<"CPU" =
  #dlti.target_device_spec<"cache" =
    #dlti.map<"L1" = #dlti.map<"size_in_bytes" = 65536 : i32>,
              "L1d" = #dlti.map<"size_in_bytes" = 32768 : i32> >>>

With the flat encoding, the implied structure of the key is ignored, that is the only successful query (as expressed in the Transform Dialect) is: transform.dlti.query ["CPU::cache::L1::size_in_bytes"] at %op, where %op is a handle to an operation which associates the flat-encoding #dlti.map attribute.

For querying nested dictionaries, the relevant keys need to be separately provided. That is, if %op is an handle to an op which has the nesting #dlti.target_system_spec-attribute from above attached, then transform.dlti.query ["CPU","cache","L1","size_in_bytes"] at %op gives back the first leaf value contained. To access the other leaf, we need to do transform.dlti.query ["CPU","cache","L1d","size_in_bytes"] at %op.

Parameters: ¶

TargetDeviceSpecAttr ¶

An attribute to represent target device specification.

Each device specification describes a single device and its hardware properties. Each device specification can contain any number of optional hardware properties (e.g., max_vector_op_width below).

Example:

#dlti.target_device_spec<"max_vector_op_width" = 64 : ui32>

Parameters: ¶

TargetSystemSpecAttr ¶

An attribute to represent target system specification.

A system specification describes the overall system containing multiple devices, with each device having a unique ID (string) and its corresponding TargetDeviceSpec object.

Example:

dlti.target_system_spec =
 #dlti.target_system_spec<
  "CPU" = #dlti.target_device_spec<
    "L1_cache_size_in_bytes" = 4096: ui32>,
  "GPU" = #dlti.target_device_spec<
    "max_vector_op_width" = 64 : ui32>,
  "XPU" = #dlti.target_device_spec<
    "max_vector_op_width" = 4096 : ui32>>

The verifier checks that keys are strings and pointed to values implement DLTI’s TargetDeviceSpecInterface.

Parameters: ¶