2 use std::path::{Path, PathBuf};
3 use std::process::Command;
5 use build_helper::{output, tracked_env_var_os};
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 tracked_env_var_os("LLVM_LINK_SHARED").is_some() {
11 ("dylib", "--link-shared")
13 ("static", "--link-static")
18 if tracked_env_var_os("RUST_CHECK").is_some() {
19 // If we're just running `check`, there's no need for LLVM to be built.
23 build_helper::restore_library_path();
25 let target = env::var("TARGET").expect("TARGET was not set");
27 tracked_env_var_os("LLVM_CONFIG").map(|x| Some(PathBuf::from(x))).unwrap_or_else(|| {
28 if let Some(dir) = tracked_env_var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
35 .join("llvm/bin/llvm-config");
36 if Command::new(&to_test).output().is_ok() {
43 if let Some(llvm_config) = &llvm_config {
44 println!("cargo:rerun-if-changed={}", llvm_config.display());
46 let llvm_config = llvm_config.unwrap_or_else(|| PathBuf::from("llvm-config"));
48 // Test whether we're cross-compiling LLVM. This is a pretty rare case
49 // currently where we're producing an LLVM for a different platform than
50 // what this build script is currently running on.
52 // In that case, there's no guarantee that we can actually run the target,
53 // so the build system works around this by giving us the LLVM_CONFIG for
54 // the host platform. This only really works if the host LLVM and target
55 // LLVM are compiled the same way, but for us that's typically the case.
57 // We *want* detect this cross compiling situation by asking llvm-config
58 // what its host-target is. If that's not the TARGET, then we're cross
59 // compiling. Unfortunately `llvm-config` seems either be buggy, or we're
60 // misconfiguring it, because the `i686-pc-windows-gnu` build of LLVM will
61 // report itself with a `--host-target` of `x86_64-pc-windows-gnu`. This
62 // tricks us into thinking we're doing a cross build when we aren't, so
65 // In any case, if we're cross compiling, this generally just means that we
66 // can't trust all the output of llvm-config because it might be targeted
67 // for the host rather than the target. As a result a bunch of blocks below
68 // are gated on `if !is_crossed`
69 let target = env::var("TARGET").expect("TARGET was not set");
70 let host = env::var("HOST").expect("HOST was not set");
71 let is_crossed = target != host;
73 let mut optional_components = vec![
90 let mut version_cmd = Command::new(&llvm_config);
91 version_cmd.arg("--version");
92 let version_output = output(&mut version_cmd);
93 let mut parts = version_output.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
94 let (major, _minor) = if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
101 optional_components.push("riscv");
104 let required_components = &[
115 let components = output(Command::new(&llvm_config).arg("--components"));
116 let mut components = components.split_whitespace().collect::<Vec<_>>();
117 components.retain(|c| optional_components.contains(c) || required_components.contains(c));
119 for component in required_components {
120 if !components.contains(component) {
121 panic!("require llvm component {} but wasn't found", component);
125 for component in components.iter() {
126 println!("cargo:rustc-cfg=llvm_component=\"{}\"", component);
130 println!("cargo:rustc-cfg=llvm_has_msp430_asm_parser");
133 // Link in our own LLVM shims, compiled with the same flags as LLVM
134 let mut cmd = Command::new(&llvm_config);
135 cmd.arg("--cxxflags");
136 let cxxflags = output(&mut cmd);
137 let mut cfg = cc::Build::new();
139 for flag in cxxflags.split_whitespace() {
140 // Ignore flags like `-m64` when we're doing a cross build
141 if is_crossed && flag.starts_with("-m") {
145 if flag.starts_with("-flto") {
149 // -Wdate-time is not supported by the netbsd cross compiler
150 if is_crossed && target.contains("netbsd") && flag.contains("date-time") {
154 // Include path contains host directory, replace it with target
155 if is_crossed && flag.starts_with("-I") {
156 cfg.flag(&flag.replace(&host, &target));
163 for component in &components {
164 let mut flag = String::from("LLVM_COMPONENT_");
165 flag.push_str(&component.to_uppercase());
166 cfg.define(&flag, None);
169 if tracked_env_var_os("LLVM_RUSTLLVM").is_some() {
170 cfg.define("LLVM_RUSTLLVM", None);
173 if tracked_env_var_os("LLVM_NDEBUG").is_some() {
174 cfg.define("NDEBUG", None);
178 build_helper::rerun_if_changed_anything_in_dir(Path::new("llvm-wrapper"));
179 cfg.file("llvm-wrapper/PassWrapper.cpp")
180 .file("llvm-wrapper/RustWrapper.cpp")
181 .file("llvm-wrapper/ArchiveWrapper.cpp")
182 .file("llvm-wrapper/CoverageMappingWrapper.cpp")
183 .file("llvm-wrapper/Linker.cpp")
185 .cpp_link_stdlib(None) // we handle this below
186 .compile("llvm-wrapper");
188 let (llvm_kind, llvm_link_arg) = detect_llvm_link();
190 // Link in all LLVM libraries, if we're using the "wrong" llvm-config then
191 // we don't pick up system libs because unfortunately they're for the host
192 // of llvm-config, not the target that we're attempting to link.
193 let mut cmd = Command::new(&llvm_config);
194 cmd.arg(llvm_link_arg).arg("--libs");
197 cmd.arg("--system-libs");
198 } else if target.contains("windows-gnu") {
199 println!("cargo:rustc-link-lib=shell32");
200 println!("cargo:rustc-link-lib=uuid");
201 } else if target.contains("netbsd") || target.contains("haiku") {
202 println!("cargo:rustc-link-lib=z");
204 cmd.args(&components);
206 for lib in output(&mut cmd).split_whitespace() {
207 let name = if lib.starts_with("-l") {
209 } else if lib.starts_with('-') {
211 } else if Path::new(lib).exists() {
212 // On MSVC llvm-config will print the full name to libraries, but
213 // we're only interested in the name part
214 let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
215 name.trim_end_matches(".lib")
216 } else if lib.ends_with(".lib") {
217 // Some MSVC libraries just come up with `.lib` tacked on, so chop
219 lib.trim_end_matches(".lib")
224 // Don't need or want this library, but LLVM's CMake build system
225 // doesn't provide a way to disable it, so filter it here even though we
226 // may or may not have built it. We don't reference anything from this
227 // library and it otherwise may just pull in extra dependencies on
228 // libedit which we don't want
229 if name == "LLVMLineEditor" {
233 let kind = if name.starts_with("LLVM") { llvm_kind } else { "dylib" };
234 println!("cargo:rustc-link-lib={}={}", kind, name);
239 // If we're a cross-compile of LLVM then unfortunately we can't trust these
240 // ldflags (largely where all the LLVM libs are located). Currently just
241 // hack around this by replacing the host triple with the target and pray
242 // that those -L directories are the same!
243 let mut cmd = Command::new(&llvm_config);
244 cmd.arg(llvm_link_arg).arg("--ldflags");
245 for lib in output(&mut cmd).split_whitespace() {
247 if lib.starts_with("-LIBPATH:") {
248 println!("cargo:rustc-link-search=native={}", lib[9..].replace(&host, &target));
249 } else if lib.starts_with("-L") {
250 println!("cargo:rustc-link-search=native={}", lib[2..].replace(&host, &target));
252 } else if lib.starts_with("-LIBPATH:") {
253 println!("cargo:rustc-link-search=native={}", &lib[9..]);
254 } else if lib.starts_with("-l") {
255 println!("cargo:rustc-link-lib={}", &lib[2..]);
256 } else if lib.starts_with("-L") {
257 println!("cargo:rustc-link-search=native={}", &lib[2..]);
261 // Some LLVM linker flags (-L and -l) may be needed even when linking
262 // rustc_llvm, for example when using static libc++, we may need to
263 // manually specify the library search path and -ldl -lpthread as link
265 let llvm_linker_flags = tracked_env_var_os("LLVM_LINKER_FLAGS");
266 if let Some(s) = llvm_linker_flags {
267 for lib in s.into_string().unwrap().split_whitespace() {
268 if lib.starts_with("-l") {
269 println!("cargo:rustc-link-lib={}", &lib[2..]);
270 } else if lib.starts_with("-L") {
271 println!("cargo:rustc-link-search=native={}", &lib[2..]);
276 let llvm_static_stdcpp = tracked_env_var_os("LLVM_STATIC_STDCPP");
277 let llvm_use_libcxx = tracked_env_var_os("LLVM_USE_LIBCXX");
279 let stdcppname = if target.contains("openbsd") {
280 if target.contains("sparc64") { "estdc++" } else { "c++" }
281 } else if target.contains("freebsd") {
283 } else if target.contains("darwin") {
285 } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
286 // NetBSD uses a separate library when relocation is required
288 } else if llvm_use_libcxx.is_some() {
294 // RISC-V requires libatomic for sub-word atomic operations
295 if target.starts_with("riscv") {
296 println!("cargo:rustc-link-lib=atomic");
299 // C++ runtime library
300 if !target.contains("msvc") {
301 if let Some(s) = llvm_static_stdcpp {
302 assert!(!cxxflags.contains("stdlib=libc++"));
303 let path = PathBuf::from(s);
304 println!("cargo:rustc-link-search=native={}", path.parent().unwrap().display());
305 if target.contains("windows") {
306 println!("cargo:rustc-link-lib=static-nobundle={}", stdcppname);
308 println!("cargo:rustc-link-lib=static={}", stdcppname);
310 } else if cxxflags.contains("stdlib=libc++") {
311 println!("cargo:rustc-link-lib=c++");
313 println!("cargo:rustc-link-lib={}", stdcppname);
317 // Libstdc++ depends on pthread which Rust doesn't link on MinGW
318 // since nothing else requires it.
319 if target.contains("windows-gnu") {
320 println!("cargo:rustc-link-lib=static-nobundle=pthread");