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// SPDX-License-Identifier: Apache-2.0
use std::cell::RefCell;
use std::collections::HashMap;
use std::env;
use std::path::{Path, PathBuf};
use std::process::Command;
use glob::{MatchOptions, Pattern};
//================================================
// Commands
thread_local! {
/// The errors encountered by the build script while executing commands.
static COMMAND_ERRORS: RefCell<HashMap<String, Vec<String>>> = RefCell::default();
}
/// Adds an error encountered by the build script while executing a command.
fn add_command_error(name: &str, path: &str, arguments: &[&str], message: String) {
COMMAND_ERRORS.with(|e| {
e.borrow_mut()
.entry(name.into())
.or_default()
.push(format!(
"couldn't execute `{} {}` (path={}) ({})",
name,
arguments.join(" "),
path,
message,
))
});
/// A struct that prints the errors encountered by the build script while
/// executing commands when dropped (unless explictly discarded).
///
/// This is handy because we only want to print these errors when the build
/// script fails to link to an instance of `libclang`. For example, if
/// `llvm-config` couldn't be executed but an instance of `libclang` was found
/// anyway we don't want to pollute the build output with irrelevant errors.
#[derive(Default)]
pub struct CommandErrorPrinter {
discard: bool,
impl CommandErrorPrinter {
pub fn discard(mut self) {
self.discard = true;
impl Drop for CommandErrorPrinter {
fn drop(&mut self) {
if self.discard {
return;
let errors = COMMAND_ERRORS.with(|e| e.borrow().clone());
if let Some(errors) = errors.get("llvm-config") {
println!(
"cargo:warning=could not execute `llvm-config` one or more \
times, if the LLVM_CONFIG_PATH environment variable is set to \
a full path to valid `llvm-config` executable it will be used \
to try to find an instance of `libclang` on your system: {}",
errors
.iter()
.map(|e| format!("\"{}\"", e))
.collect::<Vec<_>>()
.join("\n "),
)
if let Some(errors) = errors.get("xcode-select") {
"cargo:warning=could not execute `xcode-select` one or more \
times, if a valid instance of this executable is on your PATH \
it will be used to try to find an instance of `libclang` on \
your system: {}",
#[cfg(test)]
lazy_static::lazy_static! {
pub static ref RUN_COMMAND_MOCK: std::sync::Mutex<
Option<Box<dyn Fn(&str, &str, &[&str]) -> Option<String> + Send + Sync + 'static>>,
> = std::sync::Mutex::new(None);
/// Executes a command and returns the `stdout` output if the command was
/// successfully executed (errors are added to `COMMAND_ERRORS`).
fn run_command(name: &str, path: &str, arguments: &[&str]) -> Option<String> {
if let Some(command) = &*RUN_COMMAND_MOCK.lock().unwrap() {
return command(name, path, arguments);
let output = match Command::new(path).args(arguments).output() {
Ok(output) => output,
Err(error) => {
let message = format!("error: {}", error);
add_command_error(name, path, arguments, message);
return None;
};
if output.status.success() {
Some(String::from_utf8_lossy(&output.stdout).into_owned())
} else {
let message = format!("exit code: {}", output.status);
None
/// Executes the `llvm-config` command and returns the `stdout` output if the
/// command was successfully executed (errors are added to `COMMAND_ERRORS`).
pub fn run_llvm_config(arguments: &[&str]) -> Option<String> {
let path = env::var("LLVM_CONFIG_PATH").unwrap_or_else(|_| "llvm-config".into());
run_command("llvm-config", &path, arguments)
/// Executes the `xcode-select` command and returns the `stdout` output if the
pub fn run_xcode_select(arguments: &[&str]) -> Option<String> {
run_command("xcode-select", "xcode-select", arguments)
// Search Directories
// These search directories are listed in order of
// preference, so if multiple `libclang` instances
// are found when searching matching directories,
// the `libclang` instances from earlier
// directories will be preferred (though version
// takes precedence over location).
/// `libclang` directory patterns for Haiku.
const DIRECTORIES_HAIKU: &[&str] = &[
"/boot/home/config/non-packaged/develop/lib",
"/boot/home/config/non-packaged/lib",
"/boot/system/non-packaged/develop/lib",
"/boot/system/non-packaged/lib",
"/boot/system/develop/lib",
"/boot/system/lib",
];
/// `libclang` directory patterns for Linux (and FreeBSD).
const DIRECTORIES_LINUX: &[&str] = &[
"/usr/local/llvm*/lib*",
"/usr/local/lib*/*/*",
"/usr/local/lib*/*",
"/usr/local/lib*",
"/usr/lib*/*/*",
"/usr/lib*/*",
"/usr/lib*",
/// `libclang` directory patterns for macOS.
const DIRECTORIES_MACOS: &[&str] = &[
"/usr/local/opt/llvm*/lib/llvm*/lib",
"/Library/Developer/CommandLineTools/usr/lib",
"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib",
"/usr/local/opt/llvm*/lib",
/// `libclang` directory patterns for Windows.
/// The boolean indicates whether the directory pattern should be used when
/// compiling for an MSVC target environment.
const DIRECTORIES_WINDOWS: &[(&str, bool)] = &[
// LLVM + Clang can be installed using Scoop (https://scoop.sh).
// Other Windows package managers install LLVM + Clang to other listed
// system-wide directories.
("C:\\Users\\*\\scoop\\apps\\llvm\\current\\lib", true),
("C:\\MSYS*\\MinGW*\\lib", false),
("C:\\Program Files*\\LLVM\\lib", true),
("C:\\LLVM\\lib", true),
// LLVM + Clang can be installed as a component of Visual Studio.
// https://github.com/KyleMayes/clang-sys/issues/121
("C:\\Program Files*\\Microsoft Visual Studio\\*\\VC\\Tools\\Llvm\\**\\lib", true),
/// `libclang` directory patterns for illumos
const DIRECTORIES_ILLUMOS: &[&str] = &[
"/opt/ooce/llvm-*/lib",
"/opt/ooce/clang-*/lib",
// Searching
/// Finds the files in a directory that match one or more filename glob patterns
/// and returns the paths to and filenames of those files.
fn search_directory(directory: &Path, filenames: &[String]) -> Vec<(PathBuf, String)> {
// Escape the specified directory in case it contains characters that have
// special meaning in glob patterns (e.g., `[` or `]`).
let directory = Pattern::escape(directory.to_str().unwrap());
let directory = Path::new(&directory);
// Join the escaped directory to the filename glob patterns to obtain
// complete glob patterns for the files being searched for.
let paths = filenames
.map(|f| directory.join(f).to_str().unwrap().to_owned());
// Prevent wildcards from matching path separators to ensure that the search
// is limited to the specified directory.
let mut options = MatchOptions::new();
options.require_literal_separator = true;
paths
.map(|p| glob::glob_with(&p, options))
.filter_map(Result::ok)
.flatten()
.filter_map(|p| {
let path = p.ok()?;
let filename = path.file_name()?.to_str().unwrap();
// The `libclang_shared` library has been renamed to `libclang-cpp`
// in Clang 10. This can cause instances of this library (e.g.,
// `libclang-cpp.so.10`) to be matched by patterns looking for
// instances of `libclang`.
if filename.contains("-cpp.") {
Some((path.parent().unwrap().to_owned(), filename.into()))
})
/// Finds the files in a directory (and any relevant sibling directories) that
/// match one or more filename glob patterns and returns the paths to and
/// filenames of those files.
fn search_directories(directory: &Path, filenames: &[String]) -> Vec<(PathBuf, String)> {
let mut results = search_directory(directory, filenames);
// On Windows, `libclang.dll` is usually found in the LLVM `bin` directory
// while `libclang.lib` is usually found in the LLVM `lib` directory. To
// keep things consistent with other platforms, only LLVM `lib` directories
// are included in the backup search directory globs so we need to search
// the LLVM `bin` directory here.
if target_os!("windows") && directory.ends_with("lib") {
let sibling = directory.parent().unwrap().join("bin");
results.extend(search_directory(&sibling, filenames));
results
/// Finds the `libclang` static or dynamic libraries matching one or more
/// filename glob patterns and returns the paths to and filenames of those files.
pub fn search_libclang_directories(filenames: &[String], variable: &str) -> Vec<(PathBuf, String)> {
// Search only the path indicated by the relevant environment variable
// (e.g., `LIBCLANG_PATH`) if it is set.
if let Ok(path) = env::var(variable).map(|d| Path::new(&d).to_path_buf()) {
// Check if the path is a matching file.
if let Some(parent) = path.parent() {
let filename = path.file_name().unwrap().to_str().unwrap();
let libraries = search_directories(parent, filenames);
if libraries.iter().any(|(_, f)| f == filename) {
return vec![(parent.into(), filename.into())];
// Check if the path is directory containing a matching file.
return search_directories(&path, filenames);
let mut found = vec![];
// Search the `bin` and `lib` directories in the directory returned by
// `llvm-config --prefix`.
if let Some(output) = run_llvm_config(&["--prefix"]) {
let directory = Path::new(output.lines().next().unwrap()).to_path_buf();
found.extend(search_directories(&directory.join("bin"), filenames));
found.extend(search_directories(&directory.join("lib"), filenames));
found.extend(search_directories(&directory.join("lib64"), filenames));
// Search the toolchain directory in the directory returned by
// `xcode-select --print-path`.
if target_os!("macos") {
if let Some(output) = run_xcode_select(&["--print-path"]) {
let directory = directory.join("Toolchains/XcodeDefault.xctoolchain/usr/lib");
found.extend(search_directories(&directory, filenames));
// Search the directories in the `LD_LIBRARY_PATH` environment variable.
if let Ok(path) = env::var("LD_LIBRARY_PATH") {
for directory in env::split_paths(&path) {
// Determine the `libclang` directory patterns.
let directories: Vec<&str> = if target_os!("haiku") {
DIRECTORIES_HAIKU.into()
} else if target_os!("linux") || target_os!("freebsd") {
DIRECTORIES_LINUX.into()
} else if target_os!("macos") {
DIRECTORIES_MACOS.into()
} else if target_os!("windows") {
let msvc = target_env!("msvc");
DIRECTORIES_WINDOWS
.filter(|d| d.1 || !msvc)
.map(|d| d.0)
.collect()
} else if target_os!("illumos") {
DIRECTORIES_ILLUMOS.into()
vec![]
// We use temporary directories when testing the build script so we'll
// remove the prefixes that make the directories absolute.
let directories = if test!() {
directories
.map(|d| d.strip_prefix('/').or_else(|| d.strip_prefix("C:\\")).unwrap_or(d))
// Search the directories provided by the `libclang` directory patterns.
options.case_sensitive = false;
for directory in directories.iter() {
if let Ok(directories) = glob::glob_with(directory, options) {
for directory in directories.filter_map(Result::ok).filter(|p| p.is_dir()) {
found