|[August 11, 2014]
Khronos Releases SPIR 2.0 Provisional Specification to Enable Compiler Innovation on Diverse Parallel Architectures
VANCOUVER, British Columbia --(Business Wire)--
The Khronos™ Group today announced the ratification and
public release of the SPIR™ 2.0 provisional specification that provides
a non-source encoding, and binary level portability, for OpenCL™ 2.0
device programs. SPIR (Standard Portable Intermediate Representation) is
the industry's first open, cross-platform Intermediate Representation
standard for portable heterogeneous parallel computing and is based on
LLVM IR. SPIR enables developers to avoid exposing sensitive kernel
source and enables a diversity of language front-ends to easily target
OpenCL platforms and devices in addition to OpenCL C. The SPIR
specification and registry can be found at https://www.khronos.org/registry/spir.
Before the development of SPIR, new tools and languages for accessing
parallel acceleration on heterogeneous systems required specific and
detailed knowledge to create compiler back-ends for each vendor's unique
hardware architecture. The SPIR standard enables vendors to accept and
accelerate SPIR binaries on their hardware, freeing higher-level
languages to innovate across a diverse range of platforms including
discrete accelerator boards, system on chips, graphics processors and
FPGAs. For example, the developers of OpenACC, C++ AMP and Python are
targeting SPIR to access optimized back-ends across multiple vendors.
SPIR enables a rich ecosystem of compiler middleware for portable
parallel programs by building on the strengths of LLVM and OpenCL. SPIR
2.0 is a specialization of LLVM 3.4 IR, but also encodes OpenCL-specific
semantics. The cl_khr_spir standard extension to OpenCL 1.2 and 2.0
defines how to load a SPIR instance into an OpenCL runtime. The
development of SPIR has been validated on multiple vendor
implementations of OpenCL, and has benefited from a thorough open
consultation process between Khronos and the LLVM and Clang communities.
The SPIR 2.0 provisional has been released to enable the growing
community of OpenCL developers to provide feedback before the
specification is finalized. Comments are welcome at the Khronos forum
In OpenCL 2.0, host and devic kernels can directly share complex,
pointer-containing data structures such as trees and linked lists,
providing significant programming flexibility and eliminating costly
data transfers between host and devices. SPIR 2.0 includes new
functionality to fully support new features released in OpenCL C 2.0,
Generic address space - where functions can be written without
specifying a named address space for arguments, especially useful for
those arguments that are declared to be a pointer to a type,
eliminating the need for multiple functions to be written for each
named address space used in an application;
Device side kernel enqueue - where device kernels can enqueue kernels
to the same device with no host interaction, enabling flexible work
scheduling paradigms and avoiding the need to transfer execution
control and data between the device and host, often significantly
offloading host processor bottlenecks;
C++11 atomics - a subset of C11 atomics and synchronization operations
to enable assignments in one work-item to be visible to other
work-items in a work-group, across work-groups executing on a device
or for sharing data between the OpenCL device and host;
Pipes - memory objects that store data organized as a FIFO. OpenCL 2.0
provides built-in functions for kernels to read from or write to a
pipe, providing straightforward programming of pipe data structures
that can be highly optimized by OpenCL implementers.
"AMD (News - Alert) continues to support industry standards such as OpenCL and SPIR,
which we believe is the right approach for unleashing the full potential
of heterogeneous computing," said Manju Hegde, corporate vice
president, Heterogeneous Applications and Developer Solutions, AMD.
"We are excited to see SPIR continuing to evolve to support OpenCL 2.0
and provide an improved platform for other heterogeneous language
innovation. SPIR 2.0 provides the industry with a much needed standard
binary format with sufficient flexibility to enable compiler and
languages vendors with a common cross-platform target."
In addition to the SPIR specification, Khronos is making the following
open source software components available on Github under the same
license as LLVM and Clang:
a modified Clang which generates SPIR from OpenCL C kernel language
a SPIR module verifier, written in the form of an LLVM pass;
a SPIR built-ins name mangler, written as a standalone library and
a header file containing definitions for all enumerated values in the
SPIR 1.2 uses Clang/LLVM 3.2 and SPIR 2.0 uses Clang/LLVM 3.4.
Further details on these resources can be found at: https://github.com/KhronosGroup.
OpenCL BOF at SIGGRAPH 2014
Attendees at the SIGGRAPH 2014 Conference in Vancouver are invited to
the Khronos OpenCL BOF at 3-4PM on Wednesday, August 13th at the
Marriott Pinnacle Hotel, next to the Vancouver Convention & Exhibition
Centre to hear more details around developments in the OpenCL ecosystem.
Space is limited and is available on a first-come, first-served basis.
Full details of this and other Khronos developer sessions at: https://www.khronos.org/siggraph14.
About The Khronos Group
The Khronos Group is an industry consortium creating open standards to
enable the authoring and acceleration of parallel computing, graphics,
vision, sensor processing and dynamic media on a wide variety of
platforms and devices. Khronos standards include OpenGL®,
OpenGL® ES, WebGL™, OpenCL™, SPIR™, SYCL™, WebCL™, OpenVX™,
OpenMAX™, OpenVG™, OpenSL ES™, StreamInput™, COLLADA™ and glTF™. All
Khronos members are enabled to contribute to the development of Khronos
specifications, are empowered to vote at various stages before public
deployment, and are able to accelerate the delivery of their
cutting-edge media platforms and applications through early access to
specification drafts and conformance tests. More information is
available at www.khronos.org.
Khronos, DevU, StreamInput, SPIR, SYCL, WebGL, WebCL, COLLADA, OpenKODE,
OpenVG, OpenVX, glTF, OpenSL ES and OpenMAX are trademarks of the
Khronos Group Inc. ASTC is a trademark of ARM Holdings PLC, OpenCL is a
trademark of Apple (News - Alert) Inc. and OpenGL is a registered trademark and the
OpenGL ES and OpenGL SC logos are trademarks of Silicon Graphics
International used under license by Khronos. All other product names,
trademarks, and/or company names are used solely for identification and
belong to their respective owners.
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