Name Strings

SPV_KHR_linkonce_odr

Contact

To report problems with this extension, please open a new issue at:

https://github.com/KhronosGroup/SPIRV-Registry

Contributors

  • Ben Ashbaugh, Intel

  • Mariya Podchishchaeva, Intel

  • Nicolai Hähnle, AMD

Notice

Copyright (c) 2020 The Khronos Group Inc. Copyright terms at http://www.khronos.org/registry/speccopyright.html

Status

  • Complete

  • Approved by the SPIR Working Group: 2020-06-24

  • Ratified the Khronos Group: 2020-08-14

Version

Last Modified Date

2020-05-19

Revision

1

Dependencies

This extension is written against the SPIR-V Specification, Version 1.5 Revision 2, Unified

This extension requires SPIR-V 1.0.

Overview

This extension adds a new Linkage Type LinkOnceODR. A global variable or function with such linkage type can be merged with equivalent global variables or functions from other modules during the linking process. The primary use case of this linkage type is to satisfy the C++ language One Definition Rule.

Extension Name

To use this extension within a SPIR-V module, the following OpExtension must be present in the module:

OpExtension "SPV_KHR_linkonce_odr"

Modifications to the SPIR-V Specification, Version 1.5

Linkage Type

In section 3.17 "Linkage Type" add the following row to the Linkage Type table:

Linkage Type Enabling Capabilities

2

LinkOnceODR
Same as the Export linkage type, but a function or global variable with this linkage type will be merged with other functions or global variables of the same name when linkage occurs, i.e. the linker will just pick one of them. Tools (such as optimizers) can assume that if the definition of a LinkOnceODR function or global variable gets replaced during linking by one from another module, then the replacement is equivalent, so it is correct to inline a LinkOnceODR function.

Linkage

Issues

  1. Do we need to introduce more linkage types, such as weak, weak_odr etc?

    RESOLVED: We will not add additional linkage types as part of this extension.

Revision History

Rev Date Author Changes

1

2020-05-19

Ben Ashbaugh

Initial KHR extension.