Merge pull request #3910 from tgross35/simplify-wrapper

Simplify the RUSTC_WRAPPER check

Author: tgross35

build-tmp.rs

@@ -0,0 +1,374 @@
+use std::env;
+use std::ffi::{OsStr, OsString};
+use std::process::{Command, Output};
+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: &'static [&'static str] = &[
+    "emscripten_new_stat_abi",
+    "espidf_time64",
+    "freebsd10",
+    "freebsd11",
+    "freebsd12",
+    "freebsd13",
+    "freebsd14",
+    "freebsd15",
+    "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",
+    "libc_ctest",
+];
+
+// Extra values to allow for check-cfg.
+const CHECK_CFG_EXTRA: &'static [(&'static str, &'static [&'static str])] = &[
+    ("target_os", &["switch", "aix", "ohos", "hurd", "visionos"]),
+    ("target_env", &["illumos", "wasi", "aix", "ohos"]),
+    (
+        "target_arch",
+        &["loongarch64", "mips32r6", "mips64r6", "csky"],
+    ),
+];
+
+fn main() {
+    // Avoid unnecessary re-building.
+    println!("cargo:rerun-if-changed=build.rs");
+
+    let (rustc_minor_ver, is_nightly) = rustc_minor_nightly();
+    let rustc_dep_of_std = env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
+    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() || rustc_minor_ver >= 80;
+
+    if env::var("CARGO_FEATURE_USE_STD").is_ok() {
+        println!(
+            "cargo:warning=\"libc's use_std cargo feature is deprecated since libc 0.2.55; \
+             please consider using the `std` cargo feature instead\""
+        );
+    }
+
+    // The ABI of libc used by std is backward compatible with FreeBSD 12.
+    // The ABI of libc from crates.io is backward compatible with FreeBSD 11.
+    //
+    // On CI, we detect the actual FreeBSD version and match its ABI exactly,
+    // running tests to ensure that the ABI is correct.
+    let which_freebsd = if libc_ci {
+        which_freebsd().unwrap_or(11)
+    } else if rustc_dep_of_std {
+        12
+    } else {
+        11
+    };
+    match which_freebsd {
+        x if x < 10 => panic!("FreeBSD older than 10 is not supported"),
+        10 => set_cfg("freebsd10"),
+        11 => set_cfg("freebsd11"),
+        12 => set_cfg("freebsd12"),
+        13 => set_cfg("freebsd13"),
+        14 => set_cfg("freebsd14"),
+        _ => set_cfg("freebsd15"),
+    }
+
+    match emcc_version_code() {
+        Some(v) if (v >= 30142) => set_cfg("emscripten_new_stat_abi"),
+        // Non-Emscripten or version < 3.1.42.
+        Some(_) | None => (),
+    }
+
+    // On CI: deny all warnings
+    if libc_ci {
+        set_cfg("libc_deny_warnings");
+    }
+
+    // Rust >= 1.15 supports private module use:
+    if rustc_minor_ver >= 15 || rustc_dep_of_std {
+        set_cfg("libc_priv_mod_use");
+    }
+
+    // Rust >= 1.19 supports unions:
+    if rustc_minor_ver >= 19 || rustc_dep_of_std {
+        set_cfg("libc_union");
+    }
+
+    // Rust >= 1.24 supports const mem::size_of:
+    if rustc_minor_ver >= 24 || rustc_dep_of_std {
+        set_cfg("libc_const_size_of");
+    }
+
+    // Rust >= 1.25 supports repr(align):
+    if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature {
+        set_cfg("libc_align");
+    }
+
+    // Rust >= 1.26 supports i128 and u128:
+    if rustc_minor_ver >= 26 || rustc_dep_of_std {
+        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 {
+        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 {
+        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 {
+        set_cfg("libc_non_exhaustive");
+    }
+
+    // Rust >= 1.47 supports long array:
+    if rustc_minor_ver >= 47 || rustc_dep_of_std {
+        set_cfg("libc_long_array");
+    }
+
+    if rustc_minor_ver >= 51 || rustc_dep_of_std {
+        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 {
+        set_cfg("libc_underscore_const_names");
+    }
+
+    // #[thread_local] is currently unstable
+    if rustc_dep_of_std {
+        set_cfg("libc_thread_local");
+    }
+
+    // Rust >= 1.62.0 allows to use `const_extern_fn` for "Rust" and "C".
+    if rustc_minor_ver >= 62 {
+        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");
+            }
+            set_cfg("libc_const_extern_fn_unstable");
+            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 {
+            if rustc_minor_ver >= 75 {
+                println!("cargo:rustc-check-cfg=cfg({})", cfg);
+            } else {
+                println!("cargo:rustc-check-cfg=values({})", cfg);
+            }
+        }
+        for &(name, values) in CHECK_CFG_EXTRA {
+            let values = values.join("\",\"");
+            if rustc_minor_ver >= 75 {
+                println!("cargo:rustc-check-cfg=cfg({},values(\"{}\"))", name, values);
+            } else {
+                println!("cargo:rustc-check-cfg=values({},\"{}\")", name, values);
+            }
+        }
+    }
+}
+
+fn rustc_version_cmd(is_clippy_driver: bool) -> Output {
+    let rustc_wrapper = env::var_os("RUSTC_WRAPPER").filter(|w| !w.is_empty());
+    let rustc = env::var_os("RUSTC").expect("Failed to get rustc version: missing RUSTC env");
+
+    let mut cmd = if let Some(wrapper) = rustc_wrapper {
+        let mut cmd = Command::new(wrapper);
+        cmd.arg(rustc);
+        if is_clippy_driver {
+            cmd.arg("--rustc");
+        }
+
+        cmd
+    } else {
+        Command::new(rustc)
+    };
+
+    cmd.arg("--version");
+
+    let output = cmd.output().expect("Failed to get rustc version");
+
+    if !output.status.success() {
+        panic!(
+            "failed to run rustc: {}",
+            String::from_utf8_lossy(output.stderr.as_slice())
+        );
+    }
+
+    output
+}
+
+fn rustc_minor_nightly() -> (u32, bool) {
+    macro_rules! otry {
+        ($e:expr) => {
+            match $e {
+                Some(e) => e,
+                None => panic!("Failed to get rustc version"),
+            }
+        };
+    }
+
+<<<<<<< HEAD
+    let rustc = env::var_os("RUSTC").expect("Failed to get rustc version: missing RUSTC env");
+    let mut cmd = match env::var_os("RUSTC_WRAPPER").as_ref() {
+        Some(wrapper) if !wrapper.is_empty() => {
+            let mut cmd = Command::new(wrapper);
+            cmd.arg(rustc);
+            cmd
+        }
+        _ => Command::new(rustc),
+    };
+||||||| parent of 18b8da967 (Handle rustc version output correctly when `clippy-driver` used)
+    let rustc = env::var_os("RUSTC").expect("Failed to get rustc version: missing RUSTC env");
+    let mut cmd = if let Some(wrapper) = env::var_os("RUSTC_WRAPPER").filter(|w| !w.is_empty()) {
+        let mut cmd = Command::new(wrapper);
+        cmd.arg(rustc);
+        cmd
+    } else {
+        Command::new(rustc)
+    };
+=======
+    let mut output = rustc_version_cmd(false);
+>>>>>>> 18b8da967 (Handle rustc version output correctly when `clippy-driver` used)
+
+<<<<<<< HEAD
+    let output = cmd
+        .arg("--version")
+        .output()
+        .ok()
+        .expect("Failed to get rustc version");
+    if !output.status.success() {
+        panic!(
+            "failed to run rustc: {}",
+            String::from_utf8_lossy(output.stderr.as_slice())
+        );
+||||||| parent of 18b8da967 (Handle rustc version output correctly when `clippy-driver` used)
+    let output = cmd
+        .arg("--version")
+        .output()
+        .expect("Failed to get rustc version");
+    if !output.status.success() {
+        panic!(
+            "failed to run rustc: {}",
+            String::from_utf8_lossy(output.stderr.as_slice())
+        );
+=======
+    if otry!(str::from_utf8(&output.stdout).ok()).starts_with("clippy") {
+        output = rustc_version_cmd(true);
+>>>>>>> 18b8da967 (Handle rustc version output correctly when `clippy-driver` used)
+    }
+
+    let version = otry!(str::from_utf8(&output.stdout).ok());
+
+    let mut pieces = version.split('.');
+
+    if pieces.next() != Some("rustc 1") {
+        panic!("Failed to get rustc version");
+    }
+
+    let minor = pieces.next();
+
+    // If `rustc` was built from a tarball, its version string
+    // will have neither a git hash nor a commit date
+    // (e.g. "rustc 1.39.0"). Treat this case as non-nightly,
+    // since a nightly build should either come from CI
+    // or a git checkout
+    let nightly_raw = otry!(pieces.next()).split('-').nth(1);
+    let nightly = nightly_raw
+        .map(|raw| raw.starts_with("dev") || raw.starts_with("nightly"))
+        .unwrap_or(false);
+    let minor = otry!(otry!(minor).parse().ok());
+
+    (minor, nightly)
+}
+
+fn which_freebsd() -> Option<i32> {
+    let output = std::process::Command::new("freebsd-version").output().ok();
+    if output.is_none() {
+        return None;
+    }
+    let output = output.unwrap();
+    if !output.status.success() {
+        return None;
+    }
+
+    let stdout = String::from_utf8(output.stdout).ok();
+    if stdout.is_none() {
+        return None;
+    }
+    let stdout = stdout.unwrap();
+
+    match &stdout {
+        s if s.starts_with("10") => Some(10),
+        s if s.starts_with("11") => Some(11),
+        s if s.starts_with("12") => Some(12),
+        s if s.starts_with("13") => Some(13),
+        s if s.starts_with("14") => Some(14),
+        s if s.starts_with("15") => Some(15),
+        _ => None,
+    }
+}
+
+fn emcc_version_code() -> Option<u64> {
+    let output = std::process::Command::new("emcc")
+        .arg("-dumpversion")
+        .output()
+        .ok();
+    if output.is_none() {
+        return None;
+    }
+    let output = output.unwrap();
+    if !output.status.success() {
+        return None;
+    }
+
+    let stdout = String::from_utf8(output.stdout).ok();
+    if stdout.is_none() {
+        return None;
+    }
+    let version = stdout.unwrap();
+
+    // Some Emscripten versions come with `-git` attached, so split the
+    // version string also on the `-` char.
+    let mut pieces = version.trim().split(|c| c == '.' || c == '-');
+
+    let major = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
+    let minor = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
+    let patch = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
+
+    Some(major * 10000 + minor * 100 + patch)
+}
+
+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);
+}

build.rs

@@ -114,10 +114,10 @@ fn main() {
 /// Run `rustc --version` and capture the output, adjusting arguments as needed if `clippy-driver`
 /// is used instead.
 fn rustc_version_cmd(is_clippy_driver: bool) -> Output {
-    let rustc_wrapper = env::var_os("RUSTC_WRAPPER").filter(|w| !w.is_empty());
     let rustc = env::var_os("RUSTC").expect("Failed to get rustc version: missing RUSTC env");
 
-    let mut cmd = match rustc_wrapper {
+    let mut cmd = match env::var_os("RUSTC_WRAPPER") {
+        Some(ref wrapper) if wrapper.is_empty() => Command::new(rustc),
         Some(wrapper) => {
             let mut cmd = Command::new(wrapper);
             cmd.arg(rustc);