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") {
157 for component in &components {
158 let mut flag = String::from("LLVM_COMPONENT_");
159 flag.push_str(&component.to_uppercase());
160 cfg.define(&flag, None);
163 if tracked_env_var_os("LLVM_RUSTLLVM").is_some() {
164 cfg.define("LLVM_RUSTLLVM", None);
167 if tracked_env_var_os("LLVM_NDEBUG").is_some() {
168 cfg.define("NDEBUG", None);
172 build_helper::rerun_if_changed_anything_in_dir(Path::new("../rustllvm"));
173 cfg.file("../rustllvm/PassWrapper.cpp")
174 .file("../rustllvm/RustWrapper.cpp")
175 .file("../rustllvm/ArchiveWrapper.cpp")
176 .file("../rustllvm/CoverageMappingWrapper.cpp")
177 .file("../rustllvm/Linker.cpp")
179 .cpp_link_stdlib(None) // we handle this below
180 .compile("rustllvm");
182 let (llvm_kind, llvm_link_arg) = detect_llvm_link();
184 // Link in all LLVM libraries, if we're using the "wrong" llvm-config then
185 // we don't pick up system libs because unfortunately they're for the host
186 // of llvm-config, not the target that we're attempting to link.
187 let mut cmd = Command::new(&llvm_config);
188 cmd.arg(llvm_link_arg).arg("--libs");
191 cmd.arg("--system-libs");
193 cmd.args(&components);
195 for lib in output(&mut cmd).split_whitespace() {
196 let name = if lib.starts_with("-l") {
198 } else if lib.starts_with('-') {
200 } else if Path::new(lib).exists() {
201 // On MSVC llvm-config will print the full name to libraries, but
202 // we're only interested in the name part
203 let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
204 name.trim_end_matches(".lib")
205 } else if lib.ends_with(".lib") {
206 // Some MSVC libraries just come up with `.lib` tacked on, so chop
208 lib.trim_end_matches(".lib")
213 // Don't need or want this library, but LLVM's CMake build system
214 // doesn't provide a way to disable it, so filter it here even though we
215 // may or may not have built it. We don't reference anything from this
216 // library and it otherwise may just pull in extra dependencies on
217 // libedit which we don't want
218 if name == "LLVMLineEditor" {
222 let kind = if name.starts_with("LLVM") { llvm_kind } else { "dylib" };
223 println!("cargo:rustc-link-lib={}={}", kind, name);
228 // If we're a cross-compile of LLVM then unfortunately we can't trust these
229 // ldflags (largely where all the LLVM libs are located). Currently just
230 // hack around this by replacing the host triple with the target and pray
231 // that those -L directories are the same!
232 let mut cmd = Command::new(&llvm_config);
233 cmd.arg(llvm_link_arg).arg("--ldflags");
234 for lib in output(&mut cmd).split_whitespace() {
236 if lib.starts_with("-LIBPATH:") {
237 println!("cargo:rustc-link-search=native={}", lib[9..].replace(&host, &target));
238 } else if lib.starts_with("-L") {
239 println!("cargo:rustc-link-search=native={}", lib[2..].replace(&host, &target));
241 } else if lib.starts_with("-LIBPATH:") {
242 println!("cargo:rustc-link-search=native={}", &lib[9..]);
243 } else if lib.starts_with("-l") {
244 println!("cargo:rustc-link-lib={}", &lib[2..]);
245 } else if lib.starts_with("-L") {
246 println!("cargo:rustc-link-search=native={}", &lib[2..]);
250 // Some LLVM linker flags (-L and -l) may be needed even when linking
251 // librustc_llvm, for example when using static libc++, we may need to
252 // manually specify the library search path and -ldl -lpthread as link
254 let llvm_linker_flags = tracked_env_var_os("LLVM_LINKER_FLAGS");
255 if let Some(s) = llvm_linker_flags {
256 for lib in s.into_string().unwrap().split_whitespace() {
257 if lib.starts_with("-l") {
258 println!("cargo:rustc-link-lib={}", &lib[2..]);
259 } else if lib.starts_with("-L") {
260 println!("cargo:rustc-link-search=native={}", &lib[2..]);
265 let llvm_static_stdcpp = tracked_env_var_os("LLVM_STATIC_STDCPP");
266 let llvm_use_libcxx = tracked_env_var_os("LLVM_USE_LIBCXX");
268 let stdcppname = if target.contains("openbsd") {
269 if target.contains("sparc64") { "estdc++" } else { "c++" }
270 } else if target.contains("freebsd") {
272 } else if target.contains("darwin") {
274 } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
275 // NetBSD uses a separate library when relocation is required
277 } else if llvm_use_libcxx.is_some() {
283 // RISC-V requires libatomic for sub-word atomic operations
284 if target.starts_with("riscv") {
285 println!("cargo:rustc-link-lib=atomic");
288 // C++ runtime library
289 if !target.contains("msvc") {
290 if let Some(s) = llvm_static_stdcpp {
291 assert!(!cxxflags.contains("stdlib=libc++"));
292 let path = PathBuf::from(s);
293 println!("cargo:rustc-link-search=native={}", path.parent().unwrap().display());
294 if target.contains("windows") {
295 println!("cargo:rustc-link-lib=static-nobundle={}", stdcppname);
297 println!("cargo:rustc-link-lib=static={}", stdcppname);
299 } else if cxxflags.contains("stdlib=libc++") {
300 println!("cargo:rustc-link-lib=c++");
302 println!("cargo:rustc-link-lib={}", stdcppname);
306 // Libstdc++ depends on pthread which Rust doesn't link on MinGW
307 // since nothing else requires it.
308 if target.contains("windows-gnu") {
309 println!("cargo:rustc-link-lib=static-nobundle=pthread");