2 use std::path::{Path, PathBuf};
3 use std::process::Command;
5 use build_helper::output;
7 fn detect_llvm_link() -> (&'static str, &'static str) {
8 // Force the link mode we want, preferring static by default, but
9 // possibly overridden by `configure --enable-llvm-link-shared`.
10 if env::var_os("LLVM_LINK_SHARED").is_some() {
11 ("dylib", "--link-shared")
13 ("static", "--link-static")
18 println!("cargo:rerun-if-env-changed=RUST_CHECK");
19 if env::var_os("RUST_CHECK").is_some() {
20 // If we're just running `check`, there's no need for LLVM to be built.
24 build_helper::restore_library_path();
26 let target = env::var("TARGET").expect("TARGET was not set");
28 env::var_os("LLVM_CONFIG").map(|x| Some(PathBuf::from(x))).unwrap_or_else(|| {
29 if let Some(dir) = env::var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
36 .join("llvm/bin/llvm-config");
37 if Command::new(&to_test).output().is_ok() {
44 if let Some(llvm_config) = &llvm_config {
45 println!("cargo:rerun-if-changed={}", llvm_config.display());
47 let llvm_config = llvm_config.unwrap_or_else(|| PathBuf::from("llvm-config"));
49 println!("cargo:rerun-if-env-changed=LLVM_CONFIG");
51 // Test whether we're cross-compiling LLVM. This is a pretty rare case
52 // currently where we're producing an LLVM for a different platform than
53 // what this build script is currently running on.
55 // In that case, there's no guarantee that we can actually run the target,
56 // so the build system works around this by giving us the LLVM_CONFIG for
57 // the host platform. This only really works if the host LLVM and target
58 // LLVM are compiled the same way, but for us that's typically the case.
60 // We *want* detect this cross compiling situation by asking llvm-config
61 // what its host-target is. If that's not the TARGET, then we're cross
62 // compiling. Unfortunately `llvm-config` seems either be buggy, or we're
63 // misconfiguring it, because the `i686-pc-windows-gnu` build of LLVM will
64 // report itself with a `--host-target` of `x86_64-pc-windows-gnu`. This
65 // tricks us into thinking we're doing a cross build when we aren't, so
68 // In any case, if we're cross compiling, this generally just means that we
69 // can't trust all the output of llvm-config because it might be targeted
70 // for the host rather than the target. As a result a bunch of blocks below
71 // are gated on `if !is_crossed`
72 let target = env::var("TARGET").expect("TARGET was not set");
73 let host = env::var("HOST").expect("HOST was not set");
74 let is_crossed = target != host;
76 let mut optional_components = vec![
93 let mut version_cmd = Command::new(&llvm_config);
94 version_cmd.arg("--version");
95 let version_output = output(&mut version_cmd);
96 let mut parts = version_output.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
97 let (major, _minor) = if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
104 optional_components.push("riscv");
107 let required_components =
108 &["ipo", "bitreader", "bitwriter", "linker", "asmparser", "lto", "instrumentation"];
110 let components = output(Command::new(&llvm_config).arg("--components"));
111 let mut components = components.split_whitespace().collect::<Vec<_>>();
112 components.retain(|c| optional_components.contains(c) || required_components.contains(c));
114 for component in required_components {
115 if !components.contains(component) {
116 panic!("require llvm component {} but wasn't found", component);
120 for component in components.iter() {
121 println!("cargo:rustc-cfg=llvm_component=\"{}\"", component);
125 println!("cargo:rustc-cfg=llvm_has_msp430_asm_parser");
128 // Link in our own LLVM shims, compiled with the same flags as LLVM
129 let mut cmd = Command::new(&llvm_config);
130 cmd.arg("--cxxflags");
131 let cxxflags = output(&mut cmd);
132 let mut cfg = cc::Build::new();
134 for flag in cxxflags.split_whitespace() {
135 // Ignore flags like `-m64` when we're doing a cross build
136 if is_crossed && flag.starts_with("-m") {
140 if flag.starts_with("-flto") {
144 // -Wdate-time is not supported by the netbsd cross compiler
145 if is_crossed && target.contains("netbsd") && flag.contains("date-time") {
152 for component in &components {
153 let mut flag = String::from("LLVM_COMPONENT_");
154 flag.push_str(&component.to_uppercase());
155 cfg.define(&flag, None);
158 println!("cargo:rerun-if-changed-env=LLVM_RUSTLLVM");
159 if env::var_os("LLVM_RUSTLLVM").is_some() {
160 cfg.define("LLVM_RUSTLLVM", None);
163 if env::var_os("LLVM_NDEBUG").is_some() {
164 cfg.define("NDEBUG", None);
168 build_helper::rerun_if_changed_anything_in_dir(Path::new("../rustllvm"));
169 cfg.file("../rustllvm/PassWrapper.cpp")
170 .file("../rustllvm/RustWrapper.cpp")
171 .file("../rustllvm/ArchiveWrapper.cpp")
172 .file("../rustllvm/Linker.cpp")
174 .cpp_link_stdlib(None) // we handle this below
175 .compile("rustllvm");
177 let (llvm_kind, llvm_link_arg) = detect_llvm_link();
179 // Link in all LLVM libraries, if we're using the "wrong" llvm-config then
180 // we don't pick up system libs because unfortunately they're for the host
181 // of llvm-config, not the target that we're attempting to link.
182 let mut cmd = Command::new(&llvm_config);
183 cmd.arg(llvm_link_arg).arg("--libs");
186 cmd.arg("--system-libs");
188 cmd.args(&components);
190 for lib in output(&mut cmd).split_whitespace() {
191 let name = if lib.starts_with("-l") {
193 } else if lib.starts_with('-') {
195 } else if Path::new(lib).exists() {
196 // On MSVC llvm-config will print the full name to libraries, but
197 // we're only interested in the name part
198 let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
199 name.trim_end_matches(".lib")
200 } else if lib.ends_with(".lib") {
201 // Some MSVC libraries just come up with `.lib` tacked on, so chop
203 lib.trim_end_matches(".lib")
208 // Don't need or want this library, but LLVM's CMake build system
209 // doesn't provide a way to disable it, so filter it here even though we
210 // may or may not have built it. We don't reference anything from this
211 // library and it otherwise may just pull in extra dependencies on
212 // libedit which we don't want
213 if name == "LLVMLineEditor" {
217 let kind = if name.starts_with("LLVM") { llvm_kind } else { "dylib" };
218 println!("cargo:rustc-link-lib={}={}", kind, name);
223 // If we're a cross-compile of LLVM then unfortunately we can't trust these
224 // ldflags (largely where all the LLVM libs are located). Currently just
225 // hack around this by replacing the host triple with the target and pray
226 // that those -L directories are the same!
227 let mut cmd = Command::new(&llvm_config);
228 cmd.arg(llvm_link_arg).arg("--ldflags");
229 for lib in output(&mut cmd).split_whitespace() {
231 if lib.starts_with("-LIBPATH:") {
232 println!("cargo:rustc-link-search=native={}", lib[9..].replace(&host, &target));
233 } else if lib.starts_with("-L") {
234 println!("cargo:rustc-link-search=native={}", lib[2..].replace(&host, &target));
236 } else if lib.starts_with("-LIBPATH:") {
237 println!("cargo:rustc-link-search=native={}", &lib[9..]);
238 } else if lib.starts_with("-l") {
239 println!("cargo:rustc-link-lib={}", &lib[2..]);
240 } else if lib.starts_with("-L") {
241 println!("cargo:rustc-link-search=native={}", &lib[2..]);
245 // Some LLVM linker flags (-L and -l) may be needed even when linking
246 // librustc_llvm, for example when using static libc++, we may need to
247 // manually specify the library search path and -ldl -lpthread as link
249 let llvm_linker_flags = env::var_os("LLVM_LINKER_FLAGS");
250 if let Some(s) = llvm_linker_flags {
251 for lib in s.into_string().unwrap().split_whitespace() {
252 if lib.starts_with("-l") {
253 println!("cargo:rustc-link-lib={}", &lib[2..]);
254 } else if lib.starts_with("-L") {
255 println!("cargo:rustc-link-search=native={}", &lib[2..]);
260 let llvm_static_stdcpp = env::var_os("LLVM_STATIC_STDCPP");
261 let llvm_use_libcxx = env::var_os("LLVM_USE_LIBCXX");
263 let stdcppname = if target.contains("openbsd") {
264 if target.contains("sparc64") { "estdc++" } else { "c++" }
265 } else if target.contains("freebsd") {
267 } else if target.contains("darwin") {
269 } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
270 // NetBSD uses a separate library when relocation is required
272 } else if llvm_use_libcxx.is_some() {
278 // C++ runtime library
279 if !target.contains("msvc") {
280 if let Some(s) = llvm_static_stdcpp {
281 assert!(!cxxflags.contains("stdlib=libc++"));
282 let path = PathBuf::from(s);
283 println!("cargo:rustc-link-search=native={}", path.parent().unwrap().display());
284 if target.contains("windows") {
285 println!("cargo:rustc-link-lib=static-nobundle={}", stdcppname);
287 println!("cargo:rustc-link-lib=static={}", stdcppname);
289 } else if cxxflags.contains("stdlib=libc++") {
290 println!("cargo:rustc-link-lib=c++");
292 println!("cargo:rustc-link-lib={}", stdcppname);
296 // Libstdc++ depends on pthread which Rust doesn't link on MinGW
297 // since nothing else requires it.
298 if target.contains("windows-gnu") {
299 println!("cargo:rustc-link-lib=static-nobundle=pthread");