chore: add tokio_no_atomic_u64 cfg (#5226)

.github/workflows/ci.yml

@@ -44,6 +44,7 @@ jobs:
       - asan
       - cross-check
       - cross-test
+      - no-atomic-u64
       - features
       - minrust
       - minimal-versions
@@ -288,6 +289,26 @@ jobs:
         env:
           RUSTFLAGS: --cfg tokio_unstable -Dwarnings --cfg tokio_no_ipv6
 
+  # See https://github.com/tokio-rs/tokio/issues/5187
+  no-atomic-u64:
+    name: Test i686-unknown-linux-gnu without AtomicU64
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install Rust ${{ env.rust_nightly }}
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ env.rust_nightly }}
+          components: rust-src
+          override: true
+      # Install linker and libraries for i686-unknown-linux-gnu
+      - uses: taiki-e/setup-cross-toolchain-action@v1
+        with:
+          target: i686-unknown-linux-gnu
+      - run: cargo test -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --all-features
+        env:
+          RUSTFLAGS: --cfg tokio_unstable -Dwarnings --cfg tokio_no_atomic_u64
+
   features:
     name: features
     runs-on: ubuntu-latest

target-specs/i686-unknown-linux-gnu.json

@@ -0,0 +1,40 @@
+{
+  "arch": "x86",
+  "cpu": "pentium4",
+  "crt-static-respected": true,
+  "data-layout": "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-f64:32:64-f80:32-n8:16:32-S128",
+  "dynamic-linking": true,
+  "env": "gnu",
+  "has-rpath": true,
+  "has-thread-local": true,
+  "llvm-target": "i686-unknown-linux-gnu",
+  "max-atomic-width": 32,
+  "os": "linux",
+  "position-independent-executables": true,
+  "pre-link-args": {
+    "gcc": [
+      "-m32"
+    ]
+  },
+  "relro-level": "full",
+  "stack-probes": {
+    "kind": "inline-or-call",
+    "min-llvm-version-for-inline": [
+      16,
+      0,
+      0
+    ]
+  },
+  "supported-sanitizers": [
+    "address"
+  ],
+  "supported-split-debuginfo": [
+    "packed",
+    "unpacked",
+    "off"
+  ],
+  "target-family": [
+    "unix"
+  ],
+  "target-pointer-width": "32"
+}

tokio/src/macros/cfg.rs

@@ -462,12 +462,13 @@ macro_rules! cfg_has_atomic_u64 {
     ($($item:item)*) => {
         $(
             #[cfg(not(any(
-                    target_arch = "arm",
-                    target_arch = "mips",
-                    target_arch = "powerpc",
-                    target_arch = "riscv32",
-                    tokio_wasm
-                    )))]
+                target_arch = "arm",
+                target_arch = "mips",
+                target_arch = "powerpc",
+                target_arch = "riscv32",
+                tokio_wasm,
+                tokio_no_atomic_u64,
+            )))]
             $item
         )*
     }
@@ -477,12 +478,13 @@ macro_rules! cfg_not_has_atomic_u64 {
     ($($item:item)*) => {
         $(
             #[cfg(any(
-                    target_arch = "arm",
-                    target_arch = "mips",
-                    target_arch = "powerpc",
-                    target_arch = "riscv32",
-                    tokio_wasm
-                    ))]
+                target_arch = "arm",
+                target_arch = "mips",
+                target_arch = "powerpc",
+                target_arch = "riscv32",
+                tokio_wasm,
+                tokio_no_atomic_u64,
+            ))]
             $item
         )*
     }