From 88b7f0d991eacae483b23c6ab9ba1ed0a4a6bd43 Mon Sep 17 00:00:00 2001 From: Pietro Albini Date: Wed, 14 Dec 2022 13:36:09 +0100 Subject: [PATCH 1/6] refactor build script to use a function to set cfgs --- build.rs | 52 +++++++++++++++++++++++++++------------------------- 1 file changed, 27 insertions(+), 25 deletions(-) diff --git a/build.rs b/build.rs index e97be1a6ab108..9a52435e49c67 100644 --- a/build.rs +++ b/build.rs @@ -25,94 +25,92 @@ fn main() { // On CI, we detect the actual FreeBSD version and match its ABI exactly, // running tests to ensure that the ABI is correct. match which_freebsd() { - Some(10) if libc_ci || rustc_dep_of_std => { - println!("cargo:rustc-cfg=freebsd10") - } - Some(11) if libc_ci => println!("cargo:rustc-cfg=freebsd11"), - Some(12) if libc_ci => println!("cargo:rustc-cfg=freebsd12"), - Some(13) if libc_ci => println!("cargo:rustc-cfg=freebsd13"), - Some(14) if libc_ci => println!("cargo:rustc-cfg=freebsd14"), - Some(_) | None => println!("cargo:rustc-cfg=freebsd11"), + Some(10) if libc_ci || rustc_dep_of_std => set_cfg("freebsd10"), + Some(11) if libc_ci => set_cfg("freebsd11"), + Some(12) if libc_ci => set_cfg("freebsd12"), + Some(13) if libc_ci => set_cfg("freebsd13"), + Some(14) if libc_ci => set_cfg("freebsd14"), + Some(_) | None => set_cfg("freebsd11"), } // On CI: deny all warnings if libc_ci { - println!("cargo:rustc-cfg=libc_deny_warnings"); + set_cfg("libc_deny_warnings"); } // Rust >= 1.15 supports private module use: if rustc_minor_ver >= 15 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_priv_mod_use"); + set_cfg("libc_priv_mod_use"); } // Rust >= 1.19 supports unions: if rustc_minor_ver >= 19 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_union"); + set_cfg("libc_union"); } // Rust >= 1.24 supports const mem::size_of: if rustc_minor_ver >= 24 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_const_size_of"); + set_cfg("libc_const_size_of"); } // Rust >= 1.25 supports repr(align): if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature { - println!("cargo:rustc-cfg=libc_align"); + set_cfg("libc_align"); } // Rust >= 1.26 supports i128 and u128: if rustc_minor_ver >= 26 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_int128"); + set_cfg("libc_int128"); } // Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it. // Otherwise, it defines an incompatible type to retaining // backwards-compatibility. if rustc_minor_ver >= 30 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_core_cvoid"); + set_cfg("libc_core_cvoid"); } // Rust >= 1.33 supports repr(packed(N)) and cfg(target_vendor). if rustc_minor_ver >= 33 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_packedN"); - println!("cargo:rustc-cfg=libc_cfg_target_vendor"); + set_cfg("libc_packedN"); + set_cfg("libc_cfg_target_vendor"); } // Rust >= 1.40 supports #[non_exhaustive]. if rustc_minor_ver >= 40 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_non_exhaustive"); + set_cfg("libc_non_exhaustive"); } // Rust >= 1.47 supports long array: if rustc_minor_ver >= 47 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_long_array"); + set_cfg("libc_long_array"); } if rustc_minor_ver >= 51 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_ptr_addr_of"); + set_cfg("libc_ptr_addr_of"); } // Rust >= 1.37.0 allows underscores as anonymous constant names. if rustc_minor_ver >= 37 || rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_underscore_const_names"); + set_cfg("libc_underscore_const_names"); } // #[thread_local] is currently unstable if rustc_dep_of_std { - println!("cargo:rustc-cfg=libc_thread_local"); + set_cfg("libc_thread_local"); } // Rust >= 1.62.0 allows to use `const_extern_fn` for "Rust" and "C". if rustc_minor_ver >= 62 { - println!("cargo:rustc-cfg=libc_const_extern_fn"); + set_cfg("libc_const_extern_fn"); } else { // Rust < 1.62.0 requires a crate feature and feature gate. if const_extern_fn_cargo_feature { if !is_nightly || rustc_minor_ver < 40 { panic!("const-extern-fn requires a nightly compiler >= 1.40"); } - println!("cargo:rustc-cfg=libc_const_extern_fn_unstable"); - println!("cargo:rustc-cfg=libc_const_extern_fn"); + set_cfg("libc_const_extern_fn_unstable"); + set_cfg("libc_const_extern_fn"); } } } @@ -181,3 +179,7 @@ fn which_freebsd() -> Option { _ => None, } } + +fn set_cfg(cfg: &str) { + println!("cargo:rustc-cfg={}", cfg); +} From f8a12ee0a4e96f830cdc765343aa60cbe27c5a4a Mon Sep 17 00:00:00 2001 From: Pietro Albini Date: Wed, 14 Dec 2022 13:41:49 +0100 Subject: [PATCH 2/6] ensure all cfgs used are allowed --- build.rs | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/build.rs b/build.rs index 9a52435e49c67..ab299b70baa2a 100644 --- a/build.rs +++ b/build.rs @@ -2,6 +2,33 @@ use std::env; use std::process::Command; use std::str; +// List of cfgs this build script is allowed to set. The list is needed to support check-cfg, as we +// need to know all the possible cfgs that this script will set. If you need to set another cfg +// make sure to add it to this list as well. +const ALLOWED_CFGS: &[&str] = &[ + "freebsd10", + "freebsd11", + "freebsd12", + "freebsd13", + "freebsd14", + "libc_align", + "libc_cfg_target_vendor", + "libc_const_extern_fn", + "libc_const_extern_fn_unstable", + "libc_const_size_of", + "libc_core_cvoid", + "libc_deny_warnings", + "libc_int128", + "libc_long_array", + "libc_non_exhaustive", + "libc_packedN", + "libc_priv_mod_use", + "libc_ptr_addr_of", + "libc_thread_local", + "libc_underscore_const_names", + "libc_union", +]; + fn main() { // Avoid unnecessary re-building. println!("cargo:rerun-if-changed=build.rs"); @@ -181,5 +208,8 @@ fn which_freebsd() -> Option { } fn set_cfg(cfg: &str) { + if !ALLOWED_CFGS.contains(&cfg) { + panic!("trying to set cfg {}, but it is not in ALLOWED_CFGS", cfg); + } println!("cargo:rustc-cfg={}", cfg); } From b636da0a67185598bbe739ed2c20910e51514e4d Mon Sep 17 00:00:00 2001 From: Pietro Albini Date: Fri, 24 Feb 2023 11:05:44 +0100 Subject: [PATCH 3/6] emit rustc-check-cfg in the build script when LIBC_CHECK_CFG=1 --- build.rs | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/build.rs b/build.rs index ab299b70baa2a..cb70d6e238291 100644 --- a/build.rs +++ b/build.rs @@ -38,6 +38,7 @@ fn main() { let align_cargo_feature = env::var("CARGO_FEATURE_ALIGN").is_ok(); let const_extern_fn_cargo_feature = env::var("CARGO_FEATURE_CONST_EXTERN_FN").is_ok(); let libc_ci = env::var("LIBC_CI").is_ok(); + let libc_check_cfg = env::var("LIBC_CHECK_CFG").is_ok(); if env::var("CARGO_FEATURE_USE_STD").is_ok() { println!( @@ -140,6 +141,17 @@ fn main() { set_cfg("libc_const_extern_fn"); } } + + // check-cfg is a nightly cargo/rustc feature to warn when unknown cfgs are used across the + // codebase. libc can configure it if the appropriate environment variable is passed. Since + // rust-lang/rust enforces it, this is useful when using a custom libc fork there. + // + // https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#check-cfg + if libc_check_cfg { + for cfg in ALLOWED_CFGS { + println!("cargo:rustc-check-cfg=values({})", cfg); + } + } } fn rustc_minor_nightly() -> (u32, bool) { From e74f73544f29fe3559081250b9a657a36bc860eb Mon Sep 17 00:00:00 2001 From: Pietro Albini Date: Wed, 14 Dec 2022 14:41:50 +0100 Subject: [PATCH 4/6] support extra check-cfg --- build.rs | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/build.rs b/build.rs index cb70d6e238291..43a5d890d1b1e 100644 --- a/build.rs +++ b/build.rs @@ -29,6 +29,13 @@ const ALLOWED_CFGS: &[&str] = &[ "libc_union", ]; +// Extra values to allow for check-cfg. +const CHECK_CFG_EXTRA: &[(&str, &[&str])] = &[ + ("target_os", &["switch", "aix", "ohos"]), + ("target_env", &["illumos", "wasi", "aix", "ohos"]), + ("target_arch", &["loongarch64"]), +]; + fn main() { // Avoid unnecessary re-building. println!("cargo:rerun-if-changed=build.rs"); @@ -151,6 +158,10 @@ fn main() { for cfg in ALLOWED_CFGS { println!("cargo:rustc-check-cfg=values({})", cfg); } + for (name, values) in CHECK_CFG_EXTRA { + let values = values.join("\",\""); + println!("cargo:rustc-check-cfg=values({},\"{}\")", name, values); + } } } From b9a49d442bdeeac8cac3bb097f5e224e7623e037 Mon Sep 17 00:00:00 2001 From: Pietro Albini Date: Wed, 14 Dec 2022 14:46:27 +0100 Subject: [PATCH 5/6] add ci job to test check-cfg --- .github/workflows/bors.yml | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/.github/workflows/bors.yml b/.github/workflows/bors.yml index 49a06de68605a..e4e342a1b30c2 100644 --- a/.github/workflows/bors.yml +++ b/.github/workflows/bors.yml @@ -317,6 +317,23 @@ jobs: run: LIBC_CI=1 TOOLCHAIN=${{ matrix.toolchain }} WIN_TARGET=${{ matrix.target }} sh ./ci/build.sh shell: bash + check_cfg: + permissions: + actions: write # to cancel workflows (rust-lang/simpleinfra/github-actions/cancel-outdated-builds) + contents: read # to fetch code (actions/checkout) + + name: "Check #[cfg]s" + runs-on: ubuntu-22.04 + steps: + - uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master + with: + github_token: "${{ secrets.GITHUB_TOKEN }}" + - uses: actions/checkout@v3 + - name: Setup Rust toolchain + run: TOOLCHAIN=nightly sh ./ci/install-rust.sh + - name: Build with check-cfg + run: LIBC_CI=1 LIBC_CHECK_CFG=1 cargo build -Z unstable-options -Z check-cfg=features,names,values,output + docs: permissions: actions: write # to cancel workflows (rust-lang/simpleinfra/github-actions/cancel-outdated-builds) From d63eedc3a3fe078e0aa32ba5a329f10d2e63c18d Mon Sep 17 00:00:00 2001 From: Pietro Albini Date: Wed, 8 Mar 2023 09:28:12 +0100 Subject: [PATCH 6/6] compatibility with rust 1.13.0 --- build.rs | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/build.rs b/build.rs index 43a5d890d1b1e..e60672a76133b 100644 --- a/build.rs +++ b/build.rs @@ -5,7 +5,7 @@ use std::str; // List of cfgs this build script is allowed to set. The list is needed to support check-cfg, as we // need to know all the possible cfgs that this script will set. If you need to set another cfg // make sure to add it to this list as well. -const ALLOWED_CFGS: &[&str] = &[ +const ALLOWED_CFGS: &'static [&'static str] = &[ "freebsd10", "freebsd11", "freebsd12", @@ -30,7 +30,7 @@ const ALLOWED_CFGS: &[&str] = &[ ]; // Extra values to allow for check-cfg. -const CHECK_CFG_EXTRA: &[(&str, &[&str])] = &[ +const CHECK_CFG_EXTRA: &'static [(&'static str, &'static [&'static str])] = &[ ("target_os", &["switch", "aix", "ohos"]), ("target_env", &["illumos", "wasi", "aix", "ohos"]), ("target_arch", &["loongarch64"]), @@ -158,7 +158,7 @@ fn main() { for cfg in ALLOWED_CFGS { println!("cargo:rustc-check-cfg=values({})", cfg); } - for (name, values) in CHECK_CFG_EXTRA { + for &(name, values) in CHECK_CFG_EXTRA { let values = values.join("\",\""); println!("cargo:rustc-check-cfg=values({},\"{}\")", name, values); }