Move `rustllvm` into `rustc_llvm`

1 files changed, 322 insertions, 0 deletions

diff --git a/compiler/rustc_llvm/build.rs b/compiler/rustc_llvm/build.rs
new file mode 100644
index 00000000000..7f1e5cf336a
--- /dev/null
+++ b/compiler/rustc_llvm/build.rs
@@ -0,0 +1,322 @@
+use std::env;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+use build_helper::{output, tracked_env_var_os};
+
+fn detect_llvm_link() -> (&'static str, &'static str) {
+    // Force the link mode we want, preferring static by default, but
+    // possibly overridden by `configure --enable-llvm-link-shared`.
+    if tracked_env_var_os("LLVM_LINK_SHARED").is_some() {
+        ("dylib", "--link-shared")
+    } else {
+        ("static", "--link-static")
+    }
+}
+
+fn main() {
+    if tracked_env_var_os("RUST_CHECK").is_some() {
+        // If we're just running `check`, there's no need for LLVM to be built.
+        return;
+    }
+
+    build_helper::restore_library_path();
+
+    let target = env::var("TARGET").expect("TARGET was not set");
+    let llvm_config =
+        tracked_env_var_os("LLVM_CONFIG").map(|x| Some(PathBuf::from(x))).unwrap_or_else(|| {
+            if let Some(dir) = tracked_env_var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
+                let to_test = dir
+                    .parent()
+                    .unwrap()
+                    .parent()
+                    .unwrap()
+                    .join(&target)
+                    .join("llvm/bin/llvm-config");
+                if Command::new(&to_test).output().is_ok() {
+                    return Some(to_test);
+                }
+            }
+            None
+        });
+
+    if let Some(llvm_config) = &llvm_config {
+        println!("cargo:rerun-if-changed={}", llvm_config.display());
+    }
+    let llvm_config = llvm_config.unwrap_or_else(|| PathBuf::from("llvm-config"));
+
+    // Test whether we're cross-compiling LLVM. This is a pretty rare case
+    // currently where we're producing an LLVM for a different platform than
+    // what this build script is currently running on.
+    //
+    // In that case, there's no guarantee that we can actually run the target,
+    // so the build system works around this by giving us the LLVM_CONFIG for
+    // the host platform. This only really works if the host LLVM and target
+    // LLVM are compiled the same way, but for us that's typically the case.
+    //
+    // We *want* detect this cross compiling situation by asking llvm-config
+    // what its host-target is. If that's not the TARGET, then we're cross
+    // compiling. Unfortunately `llvm-config` seems either be buggy, or we're
+    // misconfiguring it, because the `i686-pc-windows-gnu` build of LLVM will
+    // report itself with a `--host-target` of `x86_64-pc-windows-gnu`. This
+    // tricks us into thinking we're doing a cross build when we aren't, so
+    // havoc ensues.
+    //
+    // In any case, if we're cross compiling, this generally just means that we
+    // can't trust all the output of llvm-config because it might be targeted
+    // for the host rather than the target. As a result a bunch of blocks below
+    // are gated on `if !is_crossed`
+    let target = env::var("TARGET").expect("TARGET was not set");
+    let host = env::var("HOST").expect("HOST was not set");
+    let is_crossed = target != host;
+
+    let mut optional_components = vec![
+        "x86",
+        "arm",
+        "aarch64",
+        "amdgpu",
+        "avr",
+        "mips",
+        "powerpc",
+        "systemz",
+        "jsbackend",
+        "webassembly",
+        "msp430",
+        "sparc",
+        "nvptx",
+        "hexagon",
+    ];
+
+    let mut version_cmd = Command::new(&llvm_config);
+    version_cmd.arg("--version");
+    let version_output = output(&mut version_cmd);
+    let mut parts = version_output.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
+    let (major, _minor) = if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
+        (major, minor)
+    } else {
+        (6, 0)
+    };
+
+    if major > 6 {
+        optional_components.push("riscv");
+    }
+
+    let required_components = &[
+        "ipo",
+        "bitreader",
+        "bitwriter",
+        "linker",
+        "asmparser",
+        "lto",
+        "coverage",
+        "instrumentation",
+    ];
+
+    let components = output(Command::new(&llvm_config).arg("--components"));
+    let mut components = components.split_whitespace().collect::<Vec<_>>();
+    components.retain(|c| optional_components.contains(c) || required_components.contains(c));
+
+    for component in required_components {
+        if !components.contains(component) {
+            panic!("require llvm component {} but wasn't found", component);
+        }
+    }
+
+    for component in components.iter() {
+        println!("cargo:rustc-cfg=llvm_component=\"{}\"", component);
+    }
+
+    if major >= 9 {
+        println!("cargo:rustc-cfg=llvm_has_msp430_asm_parser");
+    }
+
+    // Link in our own LLVM shims, compiled with the same flags as LLVM
+    let mut cmd = Command::new(&llvm_config);
+    cmd.arg("--cxxflags");
+    let cxxflags = output(&mut cmd);
+    let mut cfg = cc::Build::new();
+    cfg.warnings(false);
+    for flag in cxxflags.split_whitespace() {
+        // Ignore flags like `-m64` when we're doing a cross build
+        if is_crossed && flag.starts_with("-m") {
+            continue;
+        }
+
+        if flag.starts_with("-flto") {
+            continue;
+        }
+
+        // -Wdate-time is not supported by the netbsd cross compiler
+        if is_crossed && target.contains("netbsd") && flag.contains("date-time") {
+            continue;
+        }
+
+        // Include path contains host directory, replace it with target
+        if is_crossed && flag.starts_with("-I") {
+            cfg.flag(&flag.replace(&host, &target));
+            continue;
+        }
+
+        cfg.flag(flag);
+    }
+
+    for component in &components {
+        let mut flag = String::from("LLVM_COMPONENT_");
+        flag.push_str(&component.to_uppercase());
+        cfg.define(&flag, None);
+    }
+
+    if tracked_env_var_os("LLVM_RUSTLLVM").is_some() {
+        cfg.define("LLVM_RUSTLLVM", None);
+    }
+
+    if tracked_env_var_os("LLVM_NDEBUG").is_some() {
+        cfg.define("NDEBUG", None);
+        cfg.debug(false);
+    }
+
+    build_helper::rerun_if_changed_anything_in_dir(Path::new("llvm-wrapper"));
+    cfg.file("llvm-wrapper/PassWrapper.cpp")
+        .file("llvm-wrapper/RustWrapper.cpp")
+        .file("llvm-wrapper/ArchiveWrapper.cpp")
+        .file("llvm-wrapper/CoverageMappingWrapper.cpp")
+        .file("llvm-wrapper/Linker.cpp")
+        .cpp(true)
+        .cpp_link_stdlib(None) // we handle this below
+        .compile("llvm-wrapper");
+
+    let (llvm_kind, llvm_link_arg) = detect_llvm_link();
+
+    // Link in all LLVM libraries, if we're using the "wrong" llvm-config then
+    // we don't pick up system libs because unfortunately they're for the host
+    // of llvm-config, not the target that we're attempting to link.
+    let mut cmd = Command::new(&llvm_config);
+    cmd.arg(llvm_link_arg).arg("--libs");
+
+    if !is_crossed {
+        cmd.arg("--system-libs");
+    } else if target.contains("windows-gnu") {
+        println!("cargo:rustc-link-lib=shell32");
+        println!("cargo:rustc-link-lib=uuid");
+    } else if target.contains("netbsd") || target.contains("haiku") {
+        println!("cargo:rustc-link-lib=z");
+    }
+    cmd.args(&components);
+
+    for lib in output(&mut cmd).split_whitespace() {
+        let name = if lib.starts_with("-l") {
+            &lib[2..]
+        } else if lib.starts_with('-') {
+            &lib[1..]
+        } else if Path::new(lib).exists() {
+            // On MSVC llvm-config will print the full name to libraries, but
+            // we're only interested in the name part
+            let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
+            name.trim_end_matches(".lib")
+        } else if lib.ends_with(".lib") {
+            // Some MSVC libraries just come up with `.lib` tacked on, so chop
+            // that off
+            lib.trim_end_matches(".lib")
+        } else {
+            continue;
+        };
+
+        // Don't need or want this library, but LLVM's CMake build system
+        // doesn't provide a way to disable it, so filter it here even though we
+        // may or may not have built it. We don't reference anything from this
+        // library and it otherwise may just pull in extra dependencies on
+        // libedit which we don't want
+        if name == "LLVMLineEditor" {
+            continue;
+        }
+
+        let kind = if name.starts_with("LLVM") { llvm_kind } else { "dylib" };
+        println!("cargo:rustc-link-lib={}={}", kind, name);
+    }
+
+    // LLVM ldflags
+    //
+    // If we're a cross-compile of LLVM then unfortunately we can't trust these
+    // ldflags (largely where all the LLVM libs are located). Currently just
+    // hack around this by replacing the host triple with the target and pray
+    // that those -L directories are the same!
+    let mut cmd = Command::new(&llvm_config);
+    cmd.arg(llvm_link_arg).arg("--ldflags");
+    for lib in output(&mut cmd).split_whitespace() {
+        if is_crossed {
+            if lib.starts_with("-LIBPATH:") {
+                println!("cargo:rustc-link-search=native={}", lib[9..].replace(&host, &target));
+            } else if lib.starts_with("-L") {
+                println!("cargo:rustc-link-search=native={}", lib[2..].replace(&host, &target));
+            }
+        } else if lib.starts_with("-LIBPATH:") {
+            println!("cargo:rustc-link-search=native={}", &lib[9..]);
+        } else if lib.starts_with("-l") {
+            println!("cargo:rustc-link-lib={}", &lib[2..]);
+        } else if lib.starts_with("-L") {
+            println!("cargo:rustc-link-search=native={}", &lib[2..]);
+        }
+    }
+
+    // Some LLVM linker flags (-L and -l) may be needed even when linking
+    // rustc_llvm, for example when using static libc++, we may need to
+    // manually specify the library search path and -ldl -lpthread as link
+    // dependencies.
+    let llvm_linker_flags = tracked_env_var_os("LLVM_LINKER_FLAGS");
+    if let Some(s) = llvm_linker_flags {
+        for lib in s.into_string().unwrap().split_whitespace() {
+            if lib.starts_with("-l") {
+                println!("cargo:rustc-link-lib={}", &lib[2..]);
+            } else if lib.starts_with("-L") {
+                println!("cargo:rustc-link-search=native={}", &lib[2..]);
+            }
+        }
+    }
+
+    let llvm_static_stdcpp = tracked_env_var_os("LLVM_STATIC_STDCPP");
+    let llvm_use_libcxx = tracked_env_var_os("LLVM_USE_LIBCXX");
+
+    let stdcppname = if target.contains("openbsd") {
+        if target.contains("sparc64") { "estdc++" } else { "c++" }
+    } else if target.contains("freebsd") {
+        "c++"
+    } else if target.contains("darwin") {
+        "c++"
+    } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
+        // NetBSD uses a separate library when relocation is required
+        "stdc++_pic"
+    } else if llvm_use_libcxx.is_some() {
+        "c++"
+    } else {
+        "stdc++"
+    };
+
+    // RISC-V requires libatomic for sub-word atomic operations
+    if target.starts_with("riscv") {
+        println!("cargo:rustc-link-lib=atomic");
+    }
+
+    // C++ runtime library
+    if !target.contains("msvc") {
+        if let Some(s) = llvm_static_stdcpp {
+            assert!(!cxxflags.contains("stdlib=libc++"));
+            let path = PathBuf::from(s);
+            println!("cargo:rustc-link-search=native={}", path.parent().unwrap().display());
+            if target.contains("windows") {
+                println!("cargo:rustc-link-lib=static-nobundle={}", stdcppname);
+            } else {
+                println!("cargo:rustc-link-lib=static={}", stdcppname);
+            }
+        } else if cxxflags.contains("stdlib=libc++") {
+            println!("cargo:rustc-link-lib=c++");
+        } else {
+            println!("cargo:rustc-link-lib={}", stdcppname);
+        }
+    }
+
+    // Libstdc++ depends on pthread which Rust doesn't link on MinGW
+    // since nothing else requires it.
+    if target.contains("windows-gnu") {
+        println!("cargo:rustc-link-lib=static-nobundle=pthread");
+    }
+}