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 if env::var_os("RUST_CHECK").is_some() {
19 // If we're just running `check`, there's no need for LLVM to be built.
20 println!("cargo:rerun-if-env-changed=RUST_CHECK");
24 build_helper::restore_library_path();
26 let target = env::var("TARGET").expect("TARGET was not set");
27 let llvm_config = env::var_os("LLVM_CONFIG").map(PathBuf::from).unwrap_or_else(|| {
28 if let Some(dir) = env::var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
30 dir.parent().unwrap().parent().unwrap().join(&target).join("llvm/bin/llvm-config");
31 if Command::new(&to_test).output().is_ok() {
35 PathBuf::from("llvm-config")
38 println!("cargo:rerun-if-changed={}", llvm_config.display());
39 println!("cargo:rerun-if-env-changed=LLVM_CONFIG");
41 // Test whether we're cross-compiling LLVM. This is a pretty rare case
42 // currently where we're producing an LLVM for a different platform than
43 // what this build script is currently running on.
45 // In that case, there's no guarantee that we can actually run the target,
46 // so the build system works around this by giving us the LLVM_CONFIG for
47 // the host platform. This only really works if the host LLVM and target
48 // LLVM are compiled the same way, but for us that's typically the case.
50 // We *want* detect this cross compiling situation by asking llvm-config
51 // what its host-target is. If that's not the TARGET, then we're cross
52 // compiling. Unfortunately `llvm-config` seems either be buggy, or we're
53 // misconfiguring it, because the `i686-pc-windows-gnu` build of LLVM will
54 // report itself with a `--host-target` of `x86_64-pc-windows-gnu`. This
55 // tricks us into thinking we're doing a cross build when we aren't, so
58 // In any case, if we're cross compiling, this generally just means that we
59 // can't trust all the output of llvm-config because it might be targeted
60 // for the host rather than the target. As a result a bunch of blocks below
61 // are gated on `if !is_crossed`
62 let target = env::var("TARGET").expect("TARGET was not set");
63 let host = env::var("HOST").expect("HOST was not set");
64 let is_crossed = target != host;
66 let mut optional_components = vec![
82 let mut version_cmd = Command::new(&llvm_config);
83 version_cmd.arg("--version");
84 let version_output = output(&mut version_cmd);
85 let mut parts = version_output.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
86 let (major, _minor) = if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
93 optional_components.push("riscv");
96 let required_components =
97 &["ipo", "bitreader", "bitwriter", "linker", "asmparser", "lto", "instrumentation"];
99 let components = output(Command::new(&llvm_config).arg("--components"));
100 let mut components = components.split_whitespace().collect::<Vec<_>>();
101 components.retain(|c| optional_components.contains(c) || required_components.contains(c));
103 for component in required_components {
104 if !components.contains(component) {
105 panic!("require llvm component {} but wasn't found", component);
109 for component in components.iter() {
110 println!("cargo:rustc-cfg=llvm_component=\"{}\"", component);
114 println!("cargo:rustc-cfg=llvm_has_msp430_asm_parser");
117 // Link in our own LLVM shims, compiled with the same flags as LLVM
118 let mut cmd = Command::new(&llvm_config);
119 cmd.arg("--cxxflags");
120 let cxxflags = output(&mut cmd);
121 let mut cfg = cc::Build::new();
123 for flag in cxxflags.split_whitespace() {
124 // Ignore flags like `-m64` when we're doing a cross build
125 if is_crossed && flag.starts_with("-m") {
129 if flag.starts_with("-flto") {
133 // -Wdate-time is not supported by the netbsd cross compiler
134 if is_crossed && target.contains("netbsd") && flag.contains("date-time") {
141 for component in &components {
142 let mut flag = String::from("LLVM_COMPONENT_");
143 flag.push_str(&component.to_uppercase());
144 cfg.define(&flag, None);
147 println!("cargo:rerun-if-changed-env=LLVM_RUSTLLVM");
148 if env::var_os("LLVM_RUSTLLVM").is_some() {
149 cfg.define("LLVM_RUSTLLVM", None);
152 if env::var_os("LLVM_NDEBUG").is_some() {
153 cfg.define("NDEBUG", None);
156 build_helper::rerun_if_changed_anything_in_dir(Path::new("../rustllvm"));
157 cfg.file("../rustllvm/PassWrapper.cpp")
158 .file("../rustllvm/RustWrapper.cpp")
159 .file("../rustllvm/ArchiveWrapper.cpp")
160 .file("../rustllvm/Linker.cpp")
162 .cpp_link_stdlib(None) // we handle this below
163 .compile("rustllvm");
165 let (llvm_kind, llvm_link_arg) = detect_llvm_link();
167 // Link in all LLVM libraries, if we're using the "wrong" llvm-config then
168 // we don't pick up system libs because unfortunately they're for the host
169 // of llvm-config, not the target that we're attempting to link.
170 let mut cmd = Command::new(&llvm_config);
171 cmd.arg(llvm_link_arg).arg("--libs");
174 cmd.arg("--system-libs");
176 cmd.args(&components);
178 for lib in output(&mut cmd).split_whitespace() {
179 let name = if lib.starts_with("-l") {
181 } else if lib.starts_with("-") {
183 } else if Path::new(lib).exists() {
184 // On MSVC llvm-config will print the full name to libraries, but
185 // we're only interested in the name part
186 let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
187 name.trim_end_matches(".lib")
188 } else if lib.ends_with(".lib") {
189 // Some MSVC libraries just come up with `.lib` tacked on, so chop
191 lib.trim_end_matches(".lib")
196 // Don't need or want this library, but LLVM's CMake build system
197 // doesn't provide a way to disable it, so filter it here even though we
198 // may or may not have built it. We don't reference anything from this
199 // library and it otherwise may just pull in extra dependencies on
200 // libedit which we don't want
201 if name == "LLVMLineEditor" {
205 let kind = if name.starts_with("LLVM") { llvm_kind } else { "dylib" };
206 println!("cargo:rustc-link-lib={}={}", kind, name);
211 // If we're a cross-compile of LLVM then unfortunately we can't trust these
212 // ldflags (largely where all the LLVM libs are located). Currently just
213 // hack around this by replacing the host triple with the target and pray
214 // that those -L directories are the same!
215 let mut cmd = Command::new(&llvm_config);
216 cmd.arg(llvm_link_arg).arg("--ldflags");
217 for lib in output(&mut cmd).split_whitespace() {
219 if lib.starts_with("-LIBPATH:") {
220 println!("cargo:rustc-link-search=native={}", lib[9..].replace(&host, &target));
221 } else if lib.starts_with("-L") {
222 println!("cargo:rustc-link-search=native={}", lib[2..].replace(&host, &target));
224 } else if lib.starts_with("-LIBPATH:") {
225 println!("cargo:rustc-link-search=native={}", &lib[9..]);
226 } else if lib.starts_with("-l") {
227 println!("cargo:rustc-link-lib={}", &lib[2..]);
228 } else if lib.starts_with("-L") {
229 println!("cargo:rustc-link-search=native={}", &lib[2..]);
233 // Some LLVM linker flags (-L and -l) may be needed even when linking
234 // librustc_llvm, for example when using static libc++, we may need to
235 // manually specify the library search path and -ldl -lpthread as link
237 let llvm_linker_flags = env::var_os("LLVM_LINKER_FLAGS");
238 if let Some(s) = llvm_linker_flags {
239 for lib in s.into_string().unwrap().split_whitespace() {
240 if lib.starts_with("-l") {
241 println!("cargo:rustc-link-lib={}", &lib[2..]);
242 } else if lib.starts_with("-L") {
243 println!("cargo:rustc-link-search=native={}", &lib[2..]);
248 let llvm_static_stdcpp = env::var_os("LLVM_STATIC_STDCPP");
249 let llvm_use_libcxx = env::var_os("LLVM_USE_LIBCXX");
251 let stdcppname = if target.contains("openbsd") {
252 if target.contains("sparc64") { "estdc++" } else { "c++" }
253 } else if target.contains("freebsd") {
255 } else if target.contains("darwin") {
257 } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
258 // NetBSD uses a separate library when relocation is required
260 } else if llvm_use_libcxx.is_some() {
266 // C++ runtime library
267 if !target.contains("msvc") {
268 if let Some(s) = llvm_static_stdcpp {
269 assert!(!cxxflags.contains("stdlib=libc++"));
270 let path = PathBuf::from(s);
271 println!("cargo:rustc-link-search=native={}", path.parent().unwrap().display());
272 if target.contains("windows") {
273 println!("cargo:rustc-link-lib=static-nobundle={}", stdcppname);
275 println!("cargo:rustc-link-lib=static={}", stdcppname);
277 } else if cxxflags.contains("stdlib=libc++") {
278 println!("cargo:rustc-link-lib=c++");
280 println!("cargo:rustc-link-lib={}", stdcppname);
284 // LLVM requires symbols from this library, but apparently they're not printed
285 // during llvm-config?
286 if target.contains("windows-gnu") {
287 println!("cargo:rustc-link-lib=static-nobundle=gcc_s");
288 println!("cargo:rustc-link-lib=static-nobundle=pthread");
289 println!("cargo:rustc-link-lib=dylib=uuid");