1
0
mirror of https://github.com/fluencelabs/wasmer synced 2024-12-15 15:15:40 +00:00
wasmer/lib/llvm-backend/build.rs
2019-04-22 15:06:40 -07:00

224 lines
8.0 KiB
Rust

//! This file was mostly taken from the llvm-sys crate.
//! (https://bitbucket.org/tari/llvm-sys.rs/src/21ab524ec4df1450035df895209c3f8fbeb8775f/build.rs?at=default&fileviewer=file-view-default)
use lazy_static::lazy_static;
use regex::Regex;
use semver::Version;
use std::env;
use std::ffi::OsStr;
use std::io::{self, ErrorKind};
use std::path::PathBuf;
use std::process::Command;
lazy_static! {
/// LLVM version used by this version of the crate.
static ref CRATE_VERSION: Version = {
let crate_version = Version::parse(env!("CARGO_PKG_VERSION"))
.expect("Crate version is somehow not valid semver");
Version {
major: crate_version.major / 10,
minor: crate_version.major % 10,
.. crate_version
}
};
static ref LLVM_CONFIG_BINARY_NAMES: Vec<String> = {
vec![
"llvm-config".into(),
// format!("llvm-config-{}", CRATE_VERSION.major),
// format!("llvm-config-{}.{}", CRATE_VERSION.major, CRATE_VERSION.minor),
]
};
/// Filesystem path to an llvm-config binary for the correct version.
static ref LLVM_CONFIG_PATH: PathBuf = {
// Try llvm-config via PATH first.
if let Some(name) = locate_system_llvm_config() {
return name.into();
} else {
println!("Didn't find usable system-wide LLVM.");
}
// Did the user give us a binary path to use? If yes, try
// to use that and fail if it doesn't work.
let binary_prefix_var = "LLVM_SYS_70_PREFIX";
let path = if let Some(path) = env::var_os(&binary_prefix_var) {
Some(path.to_str().unwrap().to_owned())
} else if let Ok(mut file) = std::fs::File::open(".llvmenv") {
use std::io::Read;
let mut s = String::new();
file.read_to_string(&mut s).unwrap();
s.truncate(s.len() - 4);
Some(s)
} else {
None
};
if let Some(path) = path {
for binary_name in LLVM_CONFIG_BINARY_NAMES.iter() {
let mut pb: PathBuf = path.clone().into();
pb.push("bin");
pb.push(binary_name);
let ver = llvm_version(&pb)
.expect(&format!("Failed to execute {:?}", &pb));
if is_compatible_llvm(&ver) {
return pb;
} else {
println!("LLVM binaries specified by {} are the wrong version.
(Found {}, need {}.)", binary_prefix_var, ver, *CRATE_VERSION);
}
}
}
println!("No suitable version of LLVM was found system-wide or pointed
to by {}.
Consider using `llvmenv` to compile an appropriate copy of LLVM, and
refer to the llvm-sys documentation for more information.
llvm-sys: https://crates.io/crates/llvm-sys
llvmenv: https://crates.io/crates/llvmenv", binary_prefix_var);
panic!("Could not find a compatible version of LLVM");
};
}
/// Try to find a system-wide version of llvm-config that is compatible with
/// this crate.
///
/// Returns None on failure.
fn locate_system_llvm_config() -> Option<&'static str> {
for binary_name in LLVM_CONFIG_BINARY_NAMES.iter() {
match llvm_version(binary_name) {
Ok(ref version) if is_compatible_llvm(version) => {
// Compatible version found. Nice.
return Some(binary_name);
}
Ok(version) => {
// Version mismatch. Will try further searches, but warn that
// we're not using the system one.
println!(
"Found LLVM version {} on PATH, but need {}.",
version, *CRATE_VERSION
);
}
Err(ref e) if e.kind() == ErrorKind::NotFound => {
// Looks like we failed to execute any llvm-config. Keep
// searching.
}
// Some other error, probably a weird failure. Give up.
Err(e) => panic!("Failed to search PATH for llvm-config: {}", e),
}
}
None
}
/// Check whether the given LLVM version is compatible with this version of
/// the crate.
fn is_compatible_llvm(llvm_version: &Version) -> bool {
let strict = env::var_os(format!(
"LLVM_SYS_{}_STRICT_VERSIONING",
env!("CARGO_PKG_VERSION_MAJOR")
))
.is_some()
|| cfg!(feature = "strict-versioning");
if strict {
llvm_version.major == CRATE_VERSION.major && llvm_version.minor == CRATE_VERSION.minor
} else {
llvm_version.major >= CRATE_VERSION.major
|| (llvm_version.major == CRATE_VERSION.major
&& llvm_version.minor >= CRATE_VERSION.minor)
}
}
/// Get the output from running `llvm-config` with the given argument.
///
/// Lazily searches for or compiles LLVM as configured by the environment
/// variables.
fn llvm_config(arg: &str) -> String {
llvm_config_ex(&*LLVM_CONFIG_PATH, arg).expect("Surprising failure from llvm-config")
}
/// Invoke the specified binary as llvm-config.
///
/// Explicit version of the `llvm_config` function that bubbles errors
/// up.
fn llvm_config_ex<S: AsRef<OsStr>>(binary: S, arg: &str) -> io::Result<String> {
Command::new(binary)
.arg(arg)
.arg("--link-static") // Don't use dylib for >= 3.9
.output()
.map(|output| {
String::from_utf8(output.stdout).expect("Output from llvm-config was not valid UTF-8")
})
}
/// Get the LLVM version using llvm-config.
fn llvm_version<S: AsRef<OsStr>>(binary: S) -> io::Result<Version> {
let version_str = llvm_config_ex(binary.as_ref(), "--version")?;
// LLVM isn't really semver and uses version suffixes to build
// version strings like '3.8.0svn', so limit what we try to parse
// to only the numeric bits.
let re = Regex::new(r"^(?P<major>\d+)\.(?P<minor>\d+)(?:\.(?P<patch>\d+))??").unwrap();
let c = re
.captures(&version_str)
.expect("Could not determine LLVM version from llvm-config.");
// some systems don't have a patch number but Version wants it so we just append .0 if it isn't
// there
let s = match c.name("patch") {
None => format!("{}.0", &c[0]),
Some(_) => c[0].to_string(),
};
Ok(Version::parse(&s).unwrap())
}
fn get_llvm_cxxflags() -> String {
let output = llvm_config("--cxxflags");
// llvm-config includes cflags from its own compilation with --cflags that
// may not be relevant to us. In particularly annoying cases, these might
// include flags that aren't understood by the default compiler we're
// using. Unless requested otherwise, clean CFLAGS of options that are
// known to be possibly-harmful.
let no_clean = env::var_os(format!(
"LLVM_SYS_{}_NO_CLEAN_CFLAGS",
env!("CARGO_PKG_VERSION_MAJOR")
))
.is_some();
if no_clean || cfg!(target_env = "msvc") {
// MSVC doesn't accept -W... options, so don't try to strip them and
// possibly strip something that should be retained. Also do nothing if
// the user requests it.
return output;
}
output
.split(&[' ', '\n'][..])
.filter(|word| !word.starts_with("-W"))
.filter(|word| word != &"-fno-exceptions")
.collect::<Vec<_>>()
.join(" ")
}
fn main() {
std::env::set_var("CXXFLAGS", get_llvm_cxxflags());
cc::Build::new()
.cpp(true)
.file("cpp/object_loader.cpp")
.compile("llvm-backend");
println!("cargo:rustc-link-lib=static=llvm-backend");
println!("cargo:rerun-if-changed=build.rs");
println!("cargo:rerun-if-changed=cpp/object_loader.cpp");
println!("cargo:rerun-if-changed=cpp/object_loader.hh");
// Enable "nightly" cfg if the current compiler is nightly.
if rustc_version::version_meta().unwrap().channel == rustc_version::Channel::Nightly {
println!("cargo:rustc-cfg=nightly");
}
}