forked from OSchip/llvm-project
58 lines
1.7 KiB
ReStructuredText
58 lines
1.7 KiB
ReStructuredText
====================
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Clang Nvlink Wrapper
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====================
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.. contents::
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:local:
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.. _clang-nvlink-wrapper:
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Introduction
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============
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This tool works as a wrapper over the ``nvlink`` program. It is required
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because ``nvlink`` does not support linking of archive files implicitly. It
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transparently passes every input option and object to ``nvlink`` except archive
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files. It reads each input archive file to extract the archived cubin files as
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temporary files. These temporary (*.cubin) files are passed to ``nvlink``.
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Use Case
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========
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During linking of heterogeneous device archive libraries with an OpenMP
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program, the :doc:`ClangOffloadBundler` creates a device specific archive of
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cubin files. Such an archive is then passed to this wrapper tool to extract
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cubin files before passing to ``nvlink``.
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Working
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=======
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**Inputs**
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A command line generated by the OpenMP-Clang driver targeting NVPTX,
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containing a set of flags, cubin object files, and zero or more archive
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files.
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Example::
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clang-nvlink-wrapper main.cubin /tmp/libTest-nvptx-sm_50.a -o main-linked.out
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**Processing**
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1. From each archive file extract all cubin files as temporary files and
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store their names in a list, `CubinFiles`.
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2. Create a new command line, `NVLinkCommand`, such that
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* Program is ``nvlink``
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* All input flags are transparently passed on as flags
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* All input archive file are replaced with `CubinFiles`
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3. Execute NVLinkCommand
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::
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1. Extract (libTest-nvptx-sm_50.a) => /tmp/a.cubin /tmp/b.cubin
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2. nvlink -o a.out-openmp-nvptx64 main.cubin /tmp/a.cubin /tmp/b.cubin
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**Output**
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Output file generated by ``nvlink`` which links all cubin files.
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