blob: 3301d41cfeefa9f5c3571eaeae8914c7c7c500ab [file] [log] [blame]
//! Sanity checking performed by rustbuild before actually executing anything.
//! This module contains the implementation of ensuring that the build
//! environment looks reasonable before progressing. This will verify that
//! various programs like git and python exist, along with ensuring that all C
//! compilers for cross-compiling are found.
//! In theory if we get past this phase it's a bug if a build fails, but in
//! practice that's likely not true!
use std::collections::HashMap;
use std::env;
use std::ffi::{OsStr, OsString};
use std::fs;
use std::path::PathBuf;
use std::process::Command;
use build_helper::{output, t};
use crate::config::Target;
use crate::Build;
struct Finder {
cache: HashMap<OsString, Option<PathBuf>>,
path: OsString,
impl Finder {
fn new() -> Self {
Self { cache: HashMap::new(), path: env::var_os("PATH").unwrap_or_default() }
fn maybe_have<S: AsRef<OsStr>>(&mut self, cmd: S) -> Option<PathBuf> {
let cmd: OsString = cmd.as_ref().into();
let path = &self.path;
.or_insert_with(|| {
for path in env::split_paths(path) {
let target = path.join(&cmd);
let mut cmd_exe = cmd.clone();
if target.is_file() // some/path/git
|| path.join(&cmd_exe).exists() // some/path/git.exe
|| target.join(&cmd_exe).exists()
// some/path/git/git.exe
return Some(target);
fn must_have<S: AsRef<OsStr>>(&mut self, cmd: S) -> PathBuf {
self.maybe_have(&cmd).unwrap_or_else(|| {
panic!("\n\ncouldn't find required command: {:?}\n\n", cmd.as_ref());
pub fn check(build: &mut Build) {
let path = env::var_os("PATH").unwrap_or_default();
// On Windows, quotes are invalid characters for filename paths, and if
// one is present as part of the PATH then that can lead to the system
// being unable to identify the files properly. See
// for more details.
if cfg!(windows) && path.to_string_lossy().contains('\"') {
panic!("PATH contains invalid character '\"'");
let mut cmd_finder = Finder::new();
// If we've got a git directory we're gonna need git to update
// submodules and learn about various other aspects.
if build.rust_info.is_git() {
// We need cmake, but only if we're actually building LLVM or sanitizers.
let building_llvm = build
.map(|host| {
.map(|config| config.llvm_config.is_none())
.any(|build_llvm_ourselves| build_llvm_ourselves);
if building_llvm || build.config.sanitizers {
// Ninja is currently only used for LLVM itself.
if building_llvm {
if {
// Some Linux distros rename `ninja` to `ninja-build`.
// CMake can work with either binary name.
if cmd_finder.maybe_have("ninja-build").is_none() {
// If ninja isn't enabled but we're building for MSVC then we try
// doubly hard to enable it. It was realized in #43767 that the msbuild
// CMake generator for MSVC doesn't respect configuration options like
// disabling LLVM assertions, which can often be quite important!
// In these cases we automatically enable Ninja if we find it in the
// environment.
if ! &&"msvc") {
if cmd_finder.maybe_have("ninja").is_some() { = true;
build.config.python = build
.map(|p| cmd_finder.must_have(p))
.or_else(|| env::var_os("BOOTSTRAP_PYTHON").map(PathBuf::from)) // set by
.or_else(|| Some(cmd_finder.must_have("python")));
build.config.nodejs = build
.map(|p| cmd_finder.must_have(p))
.or_else(|| cmd_finder.maybe_have("node"))
.or_else(|| cmd_finder.maybe_have("nodejs"));
build.config.gdb = build
.map(|p| cmd_finder.must_have(p))
.or_else(|| cmd_finder.maybe_have("gdb"));
// We're gonna build some custom C code here and there, host triples
// also build some C++ shims for LLVM so we need a C++ compiler.
for target in &build.targets {
// On emscripten we don't actually need the C compiler to just
// build the target artifacts, only for testing. For the sake
// of easier bot configuration, just skip detection.
if target.contains("emscripten") {
// We don't use a C compiler on wasm32
if target.contains("wasm32") {
if !build.config.dry_run {
if let Some(ar) =*target) {
for host in &build.hosts {
if !build.config.dry_run {
// Externally configured LLVM requires FileCheck to exist
let filecheck = build.llvm_filecheck(;
if !filecheck.starts_with(&build.out) && !filecheck.exists() && build.config.codegen_tests {
panic!("FileCheck executable {:?} does not exist", filecheck);
for target in &build.targets {
// Can't compile for iOS unless we're on macOS
if target.contains("apple-ios") && !"apple-darwin") {
panic!("the iOS target is only supported on macOS");
if target.contains("-none-") || target.contains("nvptx") {
if build.no_std(*target) == Some(false) {
panic!("All the *-none-* and nvptx* targets are no-std targets")
// Make sure musl-root is valid
if target.contains("musl") {
// If this is a native target (host is also musl) and no musl-root is given,
// fall back to the system toolchain in /usr before giving up
if build.musl_root(*target).is_none() && == *target {
let target = build.config.target_config.entry(target.clone()).or_default();
target.musl_root = Some("/usr".into());
match build.musl_libdir(*target) {
Some(libdir) => {
if fs::metadata(libdir.join("libc.a")).is_err() {
panic!("couldn't find libc.a in musl libdir: {}", libdir.display());
None => panic!(
"when targeting MUSL either the rust.musl-root \
option or the target.$TARGET.musl-root option must \
be specified in config.toml"
if target.contains("msvc") {
// There are three builds of cmake on windows: MSVC, MinGW, and
// Cygwin. The Cygwin build does not have generators for Visual
// Studio, so detect that here and error.
let out = output(Command::new("cmake").arg("--help"));
if !out.contains("Visual Studio") {
cmake does not support Visual Studio generators.
This is likely due to it being an msys/cygwin build of cmake,
rather than the required windows version, built using MinGW
or Visual Studio.
If you are building under msys2 try installing the mingw-w64-x86_64-cmake
package instead of cmake:
$ pacman -R cmake && pacman -S mingw-w64-x86_64-cmake
if let Some(ref s) = build.config.ccache {
if == "stable" {
let stage0 = t!(fs::read_to_string(build.src.join("src/stage0.txt")));
if stage0.contains("\ndev:") {
"bootstrapping from a dev compiler in a stable release, but \
should only be bootstrapping from a released compiler!"