2 extern crate build_helper;
4 use std::process::Command;
6 use std::path::{PathBuf, Path};
8 use build_helper::output;
10 fn detect_llvm_link() -> (&'static str, &'static str) {
11 // Force the link mode we want, preferring static by default, but
12 // possibly overridden by `configure --enable-llvm-link-shared`.
13 if env::var_os("LLVM_LINK_SHARED").is_some() {
14 ("dylib", "--link-shared")
16 ("static", "--link-static")
21 if env::var_os("RUST_CHECK").is_some() {
22 // If we're just running `check`, there's no need for LLVM to be built.
23 println!("cargo:rerun-if-env-changed=RUST_CHECK");
27 build_helper::restore_library_path();
29 let target = env::var("TARGET").expect("TARGET was not set");
30 let llvm_config = env::var_os("LLVM_CONFIG")
33 if let Some(dir) = env::var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
34 let to_test = dir.parent()
39 .join("llvm/bin/llvm-config");
40 if Command::new(&to_test).output().is_ok() {
44 PathBuf::from("llvm-config")
47 println!("cargo:rerun-if-changed={}", llvm_config.display());
48 println!("cargo:rerun-if-env-changed=LLVM_CONFIG");
50 // Test whether we're cross-compiling LLVM. This is a pretty rare case
51 // currently where we're producing an LLVM for a different platform than
52 // what this build script is currently running on.
54 // In that case, there's no guarantee that we can actually run the target,
55 // so the build system works around this by giving us the LLVM_CONFIG for
56 // the host platform. This only really works if the host LLVM and target
57 // LLVM are compiled the same way, but for us that's typically the case.
59 // We *want* detect this cross compiling situation by asking llvm-config
60 // what it's host-target is. If that's not the TARGET, then we're cross
61 // compiling. Unfortunately `llvm-config` seems either be buggy, or we're
62 // misconfiguring it, because the `i686-pc-windows-gnu` build of LLVM will
63 // report itself with a `--host-target` of `x86_64-pc-windows-gnu`. This
64 // tricks us into thinking we're doing a cross build when we aren't, so
67 // In any case, if we're cross compiling, this generally just means that we
68 // can't trust all the output of llvm-config becaues it might be targeted
69 // for the host rather than the target. As a result a bunch of blocks below
70 // are gated on `if !is_crossed`
71 let target = env::var("TARGET").expect("TARGET was not set");
72 let host = env::var("HOST").expect("HOST was not set");
73 let is_crossed = target != host;
75 let mut optional_components =
76 vec!["x86", "arm", "aarch64", "amdgpu", "mips", "powerpc",
77 "systemz", "jsbackend", "webassembly", "msp430", "sparc", "nvptx"];
79 let mut version_cmd = Command::new(&llvm_config);
80 version_cmd.arg("--version");
81 let version_output = output(&mut version_cmd);
82 let mut parts = version_output.split('.').take(2)
83 .filter_map(|s| s.parse::<u32>().ok());
85 if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
92 optional_components.push("hexagon");
96 optional_components.push("riscv");
99 // FIXME: surely we don't need all these components, right? Stuff like mcjit
100 // or interpreter the compiler itself never uses.
101 let required_components = &["ipo",
111 let components = output(Command::new(&llvm_config).arg("--components"));
112 let mut components = components.split_whitespace().collect::<Vec<_>>();
113 components.retain(|c| optional_components.contains(c) || required_components.contains(c));
115 for component in required_components {
116 if !components.contains(component) {
117 panic!("require llvm component {} but wasn't found", component);
121 for component in components.iter() {
122 println!("cargo:rustc-cfg=llvm_component=\"{}\"", component);
125 // Link in our own LLVM shims, compiled with the same flags as LLVM
126 let mut cmd = Command::new(&llvm_config);
127 cmd.arg("--cxxflags");
128 let cxxflags = output(&mut cmd);
129 let mut cfg = cc::Build::new();
131 for flag in cxxflags.split_whitespace() {
132 // Ignore flags like `-m64` when we're doing a cross build
133 if is_crossed && flag.starts_with("-m") {
137 if flag.starts_with("-flto") {
141 // -Wdate-time is not supported by the netbsd cross compiler
142 if is_crossed && target.contains("netbsd") && flag.contains("date-time") {
149 for component in &components {
150 let mut flag = String::from("LLVM_COMPONENT_");
151 flag.push_str(&component.to_uppercase());
152 cfg.define(&flag, None);
155 println!("cargo:rerun-if-changed-env=LLVM_RUSTLLVM");
156 if env::var_os("LLVM_RUSTLLVM").is_some() {
157 cfg.define("LLVM_RUSTLLVM", None);
160 build_helper::rerun_if_changed_anything_in_dir(Path::new("../rustllvm"));
161 cfg.file("../rustllvm/PassWrapper.cpp")
162 .file("../rustllvm/RustWrapper.cpp")
163 .file("../rustllvm/ArchiveWrapper.cpp")
164 .file("../rustllvm/Linker.cpp")
166 .cpp_link_stdlib(None) // we handle this below
167 .compile("rustllvm");
169 let (llvm_kind, llvm_link_arg) = detect_llvm_link();
171 // Link in all LLVM libraries, if we're uwring the "wrong" llvm-config then
172 // we don't pick up system libs because unfortunately they're for the host
173 // of llvm-config, not the target that we're attempting to link.
174 let mut cmd = Command::new(&llvm_config);
175 cmd.arg(llvm_link_arg).arg("--libs");
178 cmd.arg("--system-libs");
180 cmd.args(&components);
182 for lib in output(&mut cmd).split_whitespace() {
183 let name = if lib.starts_with("-l") {
185 } else if lib.starts_with("-") {
187 } else if Path::new(lib).exists() {
188 // On MSVC llvm-config will print the full name to libraries, but
189 // we're only interested in the name part
190 let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
191 name.trim_end_matches(".lib")
192 } else if lib.ends_with(".lib") {
193 // Some MSVC libraries just come up with `.lib` tacked on, so chop
195 lib.trim_end_matches(".lib")
200 // Don't need or want this library, but LLVM's CMake build system
201 // doesn't provide a way to disable it, so filter it here even though we
202 // may or may not have built it. We don't reference anything from this
203 // library and it otherwise may just pull in extra dependencies on
204 // libedit which we don't want
205 if name == "LLVMLineEditor" {
209 let kind = if name.starts_with("LLVM") {
214 println!("cargo:rustc-link-lib={}={}", kind, name);
219 // If we're a cross-compile of LLVM then unfortunately we can't trust these
220 // ldflags (largely where all the LLVM libs are located). Currently just
221 // hack around this by replacing the host triple with the target and pray
222 // that those -L directories are the same!
223 let mut cmd = Command::new(&llvm_config);
224 cmd.arg(llvm_link_arg).arg("--ldflags");
225 for lib in output(&mut cmd).split_whitespace() {
226 if lib.starts_with("-LIBPATH:") {
227 println!("cargo:rustc-link-search=native={}", &lib[9..]);
228 } else if is_crossed {
229 if lib.starts_with("-L") {
230 println!("cargo:rustc-link-search=native={}",
231 lib[2..].replace(&host, &target));
233 } else if lib.starts_with("-l") {
234 println!("cargo:rustc-link-lib={}", &lib[2..]);
235 } else if lib.starts_with("-L") {
236 println!("cargo:rustc-link-search=native={}", &lib[2..]);
240 let llvm_static_stdcpp = env::var_os("LLVM_STATIC_STDCPP");
241 let llvm_use_libcxx = env::var_os("LLVM_USE_LIBCXX");
243 let stdcppname = if target.contains("openbsd") {
244 // llvm-config on OpenBSD doesn't mention stdlib=libc++
246 } else if target.contains("freebsd") {
248 } else if target.contains("darwin") {
250 } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
251 // NetBSD uses a separate library when relocation is required
253 } else if llvm_use_libcxx.is_some() {
259 // C++ runtime library
260 if !target.contains("msvc") {
261 if let Some(s) = llvm_static_stdcpp {
262 assert!(!cxxflags.contains("stdlib=libc++"));
263 let path = PathBuf::from(s);
264 println!("cargo:rustc-link-search=native={}",
265 path.parent().unwrap().display());
266 println!("cargo:rustc-link-lib=static={}", stdcppname);
267 } else if cxxflags.contains("stdlib=libc++") {
268 println!("cargo:rustc-link-lib=c++");
270 println!("cargo:rustc-link-lib={}", stdcppname);
274 // LLVM requires symbols from this library, but apparently they're not printed
275 // during llvm-config?
276 if target.contains("windows-gnu") {
277 println!("cargo:rustc-link-lib=static-nobundle=gcc_s");
278 println!("cargo:rustc-link-lib=static-nobundle=pthread");
279 println!("cargo:rustc-link-lib=dylib=uuid");