From 0226069aae38168b64714622eb9aa490c58833de Mon Sep 17 00:00:00 2001
From: Corentin Kerisit <corentin.kerisit@gmail.com>
Date: Mon, 24 Aug 2026 16:44:36 +0900
Subject: [PATCH] Add NCCL system-provided targets

---
 .github/workflows/ci.yml         | 12 ++++++++++++
 cuda/redist_proxy_targets.bzl    |  2 ++
 e2e/BUILD.bazel                  |  9 +++++++++
 nccl/build_defs/nccl.BUILD.bazel | 18 ++++++++++++++++--
 4 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2fc8a02..f90e9f4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -36,3 +36,15 @@ jobs:
       - name: Bazel analyze static cuDNN smoke (${{ matrix.cuda_version }})
         working-directory: e2e
         run: bazel build //:cudnn_static_smoke --nobuild --platforms //:platform_linux_amd64_cuda_${{ matrix.cuda_version }}
+      - name: Check NCCL system dependency purity (${{ matrix.cuda_version }})
+        working-directory: e2e
+        run: |
+          nccl_system_deps="$(bazel cquery 'deps(@cuda//nccl:nccl_system)' --output label --platforms //:platform_linux_amd64_cuda_${{ matrix.cuda_version }})"
+          if ! grep -q 'nccl_interface_library' <<< "${nccl_system_deps}"; then
+            echo '@cuda//nccl:nccl_system does not reach the NCCL interface library' >&2
+            exit 1
+          fi
+          if grep -q 'nccl_shared_library' <<< "${nccl_system_deps}"; then
+            echo '@cuda//nccl:nccl_system reaches packaged NCCL shared libraries' >&2
+            exit 1
+          fi
diff --git a/cuda/redist_proxy_targets.bzl b/cuda/redist_proxy_targets.bzl
index 8fcb2a8..1a6e197 100644
--- a/cuda/redist_proxy_targets.bzl
+++ b/cuda/redist_proxy_targets.bzl
@@ -108,8 +108,10 @@ REPO_PUBLIC_TARGETS = {
     ],
     "cuda_nccl": [
         "nccl_shared_library",
+        "nccl_interface_library",
         "nccl_static_library",
         "nccl",
+        "nccl_system",
         "nccl_static",
         "header_list",
         "headers",
diff --git a/e2e/BUILD.bazel b/e2e/BUILD.bazel
index 6faa1b9..9b055c0 100644
--- a/e2e/BUILD.bazel
+++ b/e2e/BUILD.bazel
@@ -166,6 +166,15 @@ cc_binary(
     ],
 )
 
+cc_binary(
+    name = "nccl_system_smoke",
+    srcs = ["nccl_smoke.cc"],
+    deps = [
+        ":smoke_test_common",
+        "@cuda//nccl:nccl_system",
+    ],
+)
+
 cc_binary(
     name = "nccl_static_smoke",
     srcs = ["nccl_smoke.cc"],
diff --git a/nccl/build_defs/nccl.BUILD.bazel b/nccl/build_defs/nccl.BUILD.bazel
index 66fdaf8..066f2b9 100644
--- a/nccl/build_defs/nccl.BUILD.bazel
+++ b/nccl/build_defs/nccl.BUILD.bazel
@@ -1,9 +1,9 @@
 """BUILD definitions for nccl package"""
 
-load("@rules_cc//cc:cc_library.bzl", "cc_library")
+load("@cuda_toolkit//cuda:versions_helper.bzl", "if_version_equal_or_greater_than")
 load("@rules_cc//cc:cc_import.bzl", "cc_import")
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
 load("@{cuda_redist_repo}//:version.bzl", "CUDA_VERSION")
-load("@cuda_toolkit//cuda:versions_helper.bzl", "if_version_equal_or_greater_than")
 load("//:version.bzl", "LIB_VERSIONS")
 
 cc_import(
@@ -13,6 +13,14 @@ cc_import(
     visibility = ["//visibility:public"],
 )
 
+cc_import(
+    name = "nccl_interface_library",
+    deps = [":headers"],
+    interface_library = "lib/libnccl.so",
+    system_provided = True,
+    visibility = ["//visibility:public"],
+)
+
 cc_import(
     name = "nccl_static_library",
     deps = [":headers"],
@@ -29,6 +37,12 @@ cc_library(
     visibility = ["//visibility:public"],
 )
 
+cc_library(
+    name = "nccl_system",
+    deps = [":nccl_interface_library"],
+    visibility = ["//visibility:public"],
+)
+
 cc_library(
     name = "nccl_static",
     deps = [