llvm-project

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# This file is licensed under the Apache License v2.0 with LLVM Exceptions.
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# See https://llvm.org/LICENSE.txt for license information.
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# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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"""Repository rule to statically link against the Vulkan SDK.
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Requires installing the Vulkan SDK from https://vulkan.lunarg.com/.
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If the Vulkan SDK is not installed, this generates an empty rule and you may
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encounter linker errors like `error: undefined reference to 'vkCreateInstance'`.
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"""
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def _impl(repository_ctx):
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    if "VULKAN_SDK" in repository_ctx.os.environ:
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        sdk_path = repository_ctx.os.environ["VULKAN_SDK"]
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        repository_ctx.symlink(sdk_path, "vulkan-sdk")
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        repository_ctx.file("BUILD", """
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cc_library(
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    name = "sdk",
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    srcs = select({
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        "@platforms//os:windows": [
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            "vulkan-sdk/Lib/vulkan-1.lib"
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        ],
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        "//conditions:default": [
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            "vulkan-sdk/lib/libvulkan.so.1",
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        ],
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    }),
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    visibility = ["//visibility:public"],
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)""")
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    else:
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        # Empty rule. Will fail to link for just targets that use Vulkan.
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        repository_ctx.file("BUILD", """
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cc_library(
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    name = "sdk",
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    srcs = [],
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    visibility = ["//visibility:public"],
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)""")
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vulkan_sdk_setup = repository_rule(
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    implementation = _impl,
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    local = True,
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)
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