bootstrap/utils/
shared_helpers.rs

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1//! This module serves two purposes:
2//!     1. It is part of the `utils` module and used in other parts of bootstrap.
3//!     2. It is embedded inside bootstrap shims to avoid a dependency on the bootstrap library.
4//!        Therefore, this module should never use any other bootstrap module. This reduces binary
5//!        size and improves compilation time by minimizing linking time.
6
7#![allow(dead_code)]
8
9use std::env;
10use std::ffi::OsString;
11use std::fs::OpenOptions;
12use std::io::Write;
13use std::process::Command;
14use std::str::FromStr;
15
16// If we were to declare a tests submodule here, the shim binaries that include this
17// module via `#[path]` would fail to find it, which breaks `./x check bootstrap`.
18// So instead the unit tests for this module are in `super::tests::shared_helpers_tests`.
19
20/// Returns the environment variable which the dynamic library lookup path
21/// resides in for this platform.
22pub fn dylib_path_var() -> &'static str {
23    if cfg!(target_os = "windows") {
24        "PATH"
25    } else if cfg!(target_vendor = "apple") {
26        "DYLD_LIBRARY_PATH"
27    } else if cfg!(target_os = "haiku") {
28        "LIBRARY_PATH"
29    } else if cfg!(target_os = "aix") {
30        "LIBPATH"
31    } else {
32        "LD_LIBRARY_PATH"
33    }
34}
35
36/// Parses the `dylib_path_var()` environment variable, returning a list of
37/// paths that are members of this lookup path.
38pub fn dylib_path() -> Vec<std::path::PathBuf> {
39    let var = match std::env::var_os(dylib_path_var()) {
40        Some(v) => v,
41        None => return vec![],
42    };
43    std::env::split_paths(&var).collect()
44}
45
46/// Given an executable called `name`, return the filename for the
47/// executable for a particular target.
48pub fn exe(name: &str, target: &str) -> String {
49    if target.contains("windows") {
50        format!("{name}.exe")
51    } else if target.contains("uefi") {
52        format!("{name}.efi")
53    } else if target.contains("wasm") {
54        format!("{name}.wasm")
55    } else {
56        name.to_string()
57    }
58}
59
60/// Parses the value of the "RUSTC_VERBOSE" environment variable and returns it as a `usize`.
61/// If it was not defined, returns 0 by default.
62///
63/// Panics if "RUSTC_VERBOSE" is defined with the value that is not an unsigned integer.
64pub fn parse_rustc_verbose() -> usize {
65    match env::var("RUSTC_VERBOSE") {
66        Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
67        Err(_) => 0,
68    }
69}
70
71/// Parses the value of the "RUSTC_STAGE" environment variable and returns it as a `String`.
72///
73/// If "RUSTC_STAGE" was not set, the program will be terminated with 101.
74pub fn parse_rustc_stage() -> String {
75    env::var("RUSTC_STAGE").unwrap_or_else(|_| {
76        // Don't panic here; it's reasonable to try and run these shims directly. Give a helpful error instead.
77        eprintln!("rustc shim: FATAL: RUSTC_STAGE was not set");
78        eprintln!("rustc shim: NOTE: use `x.py build -vvv` to see all environment variables set by bootstrap");
79        std::process::exit(101);
80    })
81}
82
83/// Writes the command invocation to a file if `DUMP_BOOTSTRAP_SHIMS` is set during bootstrap.
84///
85/// Before writing it, replaces user-specific values to create generic dumps for cross-environment
86/// comparisons.
87pub fn maybe_dump(dump_name: String, cmd: &Command) {
88    if let Ok(dump_dir) = env::var("DUMP_BOOTSTRAP_SHIMS") {
89        let dump_file = format!("{dump_dir}/{dump_name}");
90
91        let mut file = OpenOptions::new().create(true).append(true).open(dump_file).unwrap();
92
93        let cmd_dump = format!("{:?}\n", cmd);
94        let cmd_dump = cmd_dump.replace(&env::var("BUILD_OUT").unwrap(), "${BUILD_OUT}");
95        let cmd_dump = cmd_dump.replace(&env::var("CARGO_HOME").unwrap(), "${CARGO_HOME}");
96
97        file.write_all(cmd_dump.as_bytes()).expect("Unable to write file");
98    }
99}
100
101/// Finds `key` and returns its value from the given list of arguments `args`.
102pub fn parse_value_from_args<'a>(args: &'a [OsString], key: &str) -> Option<&'a str> {
103    let mut args = args.iter();
104    while let Some(arg) = args.next() {
105        let arg = arg.to_str().unwrap();
106
107        if let Some(value) = arg.strip_prefix(&format!("{key}=")) {
108            return Some(value);
109        } else if arg == key {
110            return args.next().map(|v| v.to_str().unwrap());
111        }
112    }
113
114    None
115}
bootstrap/utils/shared_helpers.rs

bootstrap/utils/
shared_helpers.rs
