Import subrepo gcc/:gcc at cf1f00bc038a0df769e14bb85480ab9c12eae08d

1 files changed, 1153 insertions, 0 deletions

diff --git a/gcc/src/lib.rs b/gcc/src/lib.rs
new file mode 100644
index 0000000..85d7d22
--- /dev/null
+++ b/gcc/src/lib.rs
@@ -0,0 +1,1153 @@
+//! A library for build scripts to compile custom C code
+//!
+//! This library is intended to be used as a `build-dependencies` entry in
+//! `Cargo.toml`:
+//!
+//! ```toml
+//! [build-dependencies]
+//! gcc = "0.3"
+//! ```
+//!
+//! The purpose of this crate is to provide the utility functions necessary to
+//! compile C code into a static archive which is then linked into a Rust crate.
+//! The top-level `compile_library` function serves as a convenience and more
+//! advanced configuration is available through the `Config` builder.
+//!
+//! This crate will automatically detect situations such as cross compilation or
+//! other environment variables set by Cargo and will build code appropriately.
+//!
+//! # Examples
+//!
+//! Use the default configuration:
+//!
+//! ```no_run
+//! extern crate gcc;
+//!
+//! fn main() {
+//!     gcc::compile_library("libfoo.a", &["src/foo.c"]);
+//! }
+//! ```
+//!
+//! Use more advanced configuration:
+//!
+//! ```no_run
+//! extern crate gcc;
+//!
+//! fn main() {
+//!     gcc::Config::new()
+//!                 .file("src/foo.c")
+//!                 .define("FOO", Some("bar"))
+//!                 .include("src")
+//!                 .compile("libfoo.a");
+//! }
+//! ```
+
+#![doc(html_root_url = "https://docs.rs/gcc/0.3")]
+#![cfg_attr(test, deny(warnings))]
+#![deny(missing_docs)]
+
+#[cfg(feature = "parallel")]
+extern crate rayon;
+
+use std::env;
+use std::ffi::{OsString, OsStr};
+use std::fs;
+use std::path::{PathBuf, Path};
+use std::process::{Command, Stdio, Child};
+use std::io::{self, BufReader, BufRead, Read, Write};
+use std::thread::{self, JoinHandle};
+
+#[cfg(windows)]
+mod registry;
+pub mod windows_registry;
+
+/// Extra configuration to pass to gcc.
+pub struct Config {
+    include_directories: Vec<PathBuf>,
+    definitions: Vec<(String, Option<String>)>,
+    objects: Vec<PathBuf>,
+    flags: Vec<String>,
+    files: Vec<PathBuf>,
+    cpp: bool,
+    cpp_link_stdlib: Option<Option<String>>,
+    cpp_set_stdlib: Option<String>,
+    target: Option<String>,
+    host: Option<String>,
+    out_dir: Option<PathBuf>,
+    opt_level: Option<String>,
+    debug: Option<bool>,
+    env: Vec<(OsString, OsString)>,
+    compiler: Option<PathBuf>,
+    archiver: Option<PathBuf>,
+    cargo_metadata: bool,
+    pic: Option<bool>,
+}
+
+/// Configuration used to represent an invocation of a C compiler.
+///
+/// This can be used to figure out what compiler is in use, what the arguments
+/// to it are, and what the environment variables look like for the compiler.
+/// This can be used to further configure other build systems (e.g. forward
+/// along CC and/or CFLAGS) or the `to_command` method can be used to run the
+/// compiler itself.
+pub struct Tool {
+    path: PathBuf,
+    args: Vec<OsString>,
+    env: Vec<(OsString, OsString)>,
+    family: ToolFamily
+}
+
+/// Represents the family of tools this tool belongs to.
+///
+/// Each family of tools differs in how and what arguments they accept.
+///
+/// Detection of a family is done on best-effort basis and may not accurately reflect the tool.
+#[derive(Copy, Clone, Debug)]
+enum ToolFamily {
+    /// Tool is GNU Compiler Collection-like.
+    Gnu,
+    /// Tool is Clang-like. It differs from the GCC in a sense that it accepts superset of flags
+    /// and its cross-compilation approach is different.
+    Clang,
+    /// Tool is the MSVC cl.exe.
+    Msvc,
+}
+
+impl ToolFamily {
+    /// What the flag to request debug info for this family of tools look like
+    fn debug_flag(&self) -> &'static str {
+        match *self {
+            ToolFamily::Msvc => "/Z7",
+            ToolFamily::Gnu |
+            ToolFamily::Clang => "-g",
+        }
+    }
+
+    /// What the flag to include directories into header search path looks like
+    fn include_flag(&self) -> &'static str {
+        match *self {
+            ToolFamily::Msvc => "/I",
+            ToolFamily::Gnu |
+            ToolFamily::Clang => "-I",
+        }
+    }
+
+    /// What the flag to request macro-expanded source output looks like
+    fn expand_flag(&self) -> &'static str {
+        match *self {
+            ToolFamily::Msvc => "/E",
+            ToolFamily::Gnu |
+            ToolFamily::Clang => "-E",
+        }
+    }
+}
+
+/// Compile a library from the given set of input C files.
+///
+/// This will simply compile all files into object files and then assemble them
+/// into the output. This will read the standard environment variables to detect
+/// cross compilations and such.
+///
+/// This function will also print all metadata on standard output for Cargo.
+///
+/// # Example
+///
+/// ```no_run
+/// gcc::compile_library("libfoo.a", &["foo.c", "bar.c"]);
+/// ```
+pub fn compile_library(output: &str, files: &[&str]) {
+    let mut c = Config::new();
+    for f in files.iter() {
+        c.file(*f);
+    }
+    c.compile(output);
+}
+
+impl Config {
+    /// Construct a new instance of a blank set of configuration.
+    ///
+    /// This builder is finished with the `compile` function.
+    pub fn new() -> Config {
+        Config {
+            include_directories: Vec::new(),
+            definitions: Vec::new(),
+            objects: Vec::new(),
+            flags: Vec::new(),
+            files: Vec::new(),
+            cpp: false,
+            cpp_link_stdlib: None,
+            cpp_set_stdlib: None,
+            target: None,
+            host: None,
+            out_dir: None,
+            opt_level: None,
+            debug: None,
+            env: Vec::new(),
+            compiler: None,
+            archiver: None,
+            cargo_metadata: true,
+            pic: None,
+        }
+    }
+
+    /// Add a directory to the `-I` or include path for headers
+    pub fn include<P: AsRef<Path>>(&mut self, dir: P) -> &mut Config {
+        self.include_directories.push(dir.as_ref().to_path_buf());
+        self
+    }
+
+    /// Specify a `-D` variable with an optional value.
+    pub fn define(&mut self, var: &str, val: Option<&str>) -> &mut Config {
+        self.definitions.push((var.to_string(), val.map(|s| s.to_string())));
+        self
+    }
+
+    /// Add an arbitrary object file to link in
+    pub fn object<P: AsRef<Path>>(&mut self, obj: P) -> &mut Config {
+        self.objects.push(obj.as_ref().to_path_buf());
+        self
+    }
+
+    /// Add an arbitrary flag to the invocation of the compiler
+    pub fn flag(&mut self, flag: &str) -> &mut Config {
+        self.flags.push(flag.to_string());
+        self
+    }
+
+    /// Add a file which will be compiled
+    pub fn file<P: AsRef<Path>>(&mut self, p: P) -> &mut Config {
+        self.files.push(p.as_ref().to_path_buf());
+        self
+    }
+
+    /// Set C++ support.
+    ///
+    /// The other `cpp_*` options will only become active if this is set to
+    /// `true`.
+    pub fn cpp(&mut self, cpp: bool) -> &mut Config {
+        self.cpp = cpp;
+        self
+    }
+
+    /// Set the standard library to link against when compiling with C++
+    /// support.
+    ///
+    /// The default value of this property depends on the current target: On
+    /// OS X `Some("c++")` is used, when compiling for a Visual Studio based
+    /// target `None` is used and for other targets `Some("stdc++")` is used.
+    ///
+    /// A value of `None` indicates that no automatic linking should happen,
+    /// otherwise cargo will link against the specified library.
+    ///
+    /// The given library name must not contain the `lib` prefix.
+    pub fn cpp_link_stdlib(&mut self, cpp_link_stdlib: Option<&str>) -> &mut Config {
+        self.cpp_link_stdlib = Some(cpp_link_stdlib.map(|s| s.into()));
+        self
+    }
+
+    /// Force the C++ compiler to use the specified standard library.
+    ///
+    /// Setting this option will automatically set `cpp_link_stdlib` to the same
+    /// value.
+    ///
+    /// The default value of this option is always `None`.
+    ///
+    /// This option has no effect when compiling for a Visual Studio based
+    /// target.
+    ///
+    /// This option sets the `-stdlib` flag, which is only supported by some
+    /// compilers (clang, icc) but not by others (gcc). The library will not
+    /// detect which compiler is used, as such it is the responsibility of the
+    /// caller to ensure that this option is only used in conjuction with a
+    /// compiler which supports the `-stdlib` flag.
+    ///
+    /// A value of `None` indicates that no specific C++ standard library should
+    /// be used, otherwise `-stdlib` is added to the compile invocation.
+    ///
+    /// The given library name must not contain the `lib` prefix.
+    pub fn cpp_set_stdlib(&mut self, cpp_set_stdlib: Option<&str>) -> &mut Config {
+        self.cpp_set_stdlib = cpp_set_stdlib.map(|s| s.into());
+        self.cpp_link_stdlib(cpp_set_stdlib);
+        self
+    }
+
+    /// Configures the target this configuration will be compiling for.
+    ///
+    /// This option is automatically scraped from the `TARGET` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn target(&mut self, target: &str) -> &mut Config {
+        self.target = Some(target.to_string());
+        self
+    }
+
+    /// Configures the host assumed by this configuration.
+    ///
+    /// This option is automatically scraped from the `HOST` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn host(&mut self, host: &str) -> &mut Config {
+        self.host = Some(host.to_string());
+        self
+    }
+
+    /// Configures the optimization level of the generated object files.
+    ///
+    /// This option is automatically scraped from the `OPT_LEVEL` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn opt_level(&mut self, opt_level: u32) -> &mut Config {
+        self.opt_level = Some(opt_level.to_string());
+        self
+    }
+
+    /// Configures the optimization level of the generated object files.
+    ///
+    /// This option is automatically scraped from the `OPT_LEVEL` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn opt_level_str(&mut self, opt_level: &str) -> &mut Config {
+        self.opt_level = Some(opt_level.to_string());
+        self
+    }
+
+    /// Configures whether the compiler will emit debug information when
+    /// generating object files.
+    ///
+    /// This option is automatically scraped from the `PROFILE` environment
+    /// variable by build scripts (only enabled when the profile is "debug"), so
+    /// it's not required to call this function.
+    pub fn debug(&mut self, debug: bool) -> &mut Config {
+        self.debug = Some(debug);
+        self
+    }
+
+    /// Configures the output directory where all object files and static
+    /// libraries will be located.
+    ///
+    /// This option is automatically scraped from the `OUT_DIR` environment
+    /// variable by build scripts, so it's not required to call this function.
+    pub fn out_dir<P: AsRef<Path>>(&mut self, out_dir: P) -> &mut Config {
+        self.out_dir = Some(out_dir.as_ref().to_owned());
+        self
+    }
+
+    /// Configures the compiler to be used to produce output.
+    ///
+    /// This option is automatically determined from the target platform or a
+    /// number of environment variables, so it's not required to call this
+    /// function.
+    pub fn compiler<P: AsRef<Path>>(&mut self, compiler: P) -> &mut Config {
+        self.compiler = Some(compiler.as_ref().to_owned());
+        self
+    }
+
+    /// Configures the tool used to assemble archives.
+    ///
+    /// This option is automatically determined from the target platform or a
+    /// number of environment variables, so it's not required to call this
+    /// function.
+    pub fn archiver<P: AsRef<Path>>(&mut self, archiver: P) -> &mut Config {
+        self.archiver = Some(archiver.as_ref().to_owned());
+        self
+    }
+    /// Define whether metadata should be emitted for cargo allowing it to
+    /// automatically link the binary. Defaults to `true`.
+    pub fn cargo_metadata(&mut self, cargo_metadata: bool) -> &mut Config {
+        self.cargo_metadata = cargo_metadata;
+        self
+    }
+
+    /// Configures whether the compiler will emit position independent code.
+    ///
+    /// This option defaults to `false` for `windows-gnu` targets and
+    /// to `true` for all other targets.
+    pub fn pic(&mut self, pic: bool) -> &mut Config {
+        self.pic = Some(pic);
+        self
+    }
+
+
+    #[doc(hidden)]
+    pub fn __set_env<A, B>(&mut self, a: A, b: B) -> &mut Config
+        where A: AsRef<OsStr>,
+              B: AsRef<OsStr>
+    {
+        self.env.push((a.as_ref().to_owned(), b.as_ref().to_owned()));
+        self
+    }
+
+    /// Run the compiler, generating the file `output`
+    ///
+    /// The name `output` must begin with `lib` and end with `.a`
+    pub fn compile(&self, output: &str) {
+        assert!(output.starts_with("lib"));
+        assert!(output.ends_with(".a"));
+        let lib_name = &output[3..output.len() - 2];
+        let dst = self.get_out_dir();
+
+        let mut objects = Vec::new();
+        let mut src_dst = Vec::new();
+        for file in self.files.iter() {
+            let obj = dst.join(file).with_extension("o");
+            let obj = if !obj.starts_with(&dst) {
+                dst.join(obj.file_name().unwrap())
+            } else {
+                obj
+            };
+            fs::create_dir_all(&obj.parent().unwrap()).unwrap();
+            src_dst.push((file.to_path_buf(), obj.clone()));
+            objects.push(obj);
+        }
+        self.compile_objects(&src_dst);
+        self.assemble(lib_name, &dst.join(output), &objects);
+
+        if self.get_target().contains("msvc") {
+            let compiler = self.get_base_compiler();
+            let atlmfc_lib = compiler.env()
+                .iter()
+                .find(|&&(ref var, _)| var.as_os_str() == OsStr::new("LIB"))
+                .and_then(|&(_, ref lib_paths)| {
+                    env::split_paths(lib_paths).find(|path| {
+                        let sub = Path::new("atlmfc/lib");
+                        path.ends_with(sub) || path.parent().map_or(false, |p| p.ends_with(sub))
+                    })
+                });
+
+            if let Some(atlmfc_lib) = atlmfc_lib {
+                self.print(&format!("cargo:rustc-link-search=native={}", atlmfc_lib.display()));
+            }
+        }
+
+        self.print(&format!("cargo:rustc-link-lib=static={}",
+                            &output[3..output.len() - 2]));
+        self.print(&format!("cargo:rustc-link-search=native={}", dst.display()));
+
+        // Add specific C++ libraries, if enabled.
+        if self.cpp {
+            if let Some(stdlib) = self.get_cpp_link_stdlib() {
+                self.print(&format!("cargo:rustc-link-lib={}", stdlib));
+            }
+        }
+    }
+
+    #[cfg(feature = "parallel")]
+    fn compile_objects(&self, objs: &[(PathBuf, PathBuf)]) {
+        use self::rayon::prelude::*;
+
+        let mut cfg = rayon::Configuration::new();
+        if let Ok(amt) = env::var("NUM_JOBS") {
+            if let Ok(amt) = amt.parse() {
+                cfg = cfg.set_num_threads(amt);
+            }
+        }
+        drop(rayon::initialize(cfg));
+
+        objs.par_iter().weight_max().for_each(|&(ref src, ref dst)| self.compile_object(src, dst));
+    }
+
+    #[cfg(not(feature = "parallel"))]
+    fn compile_objects(&self, objs: &[(PathBuf, PathBuf)]) {
+        for &(ref src, ref dst) in objs {
+            self.compile_object(src, dst);
+        }
+    }
+
+    fn compile_object(&self, file: &Path, dst: &Path) {
+        let is_asm = file.extension().and_then(|s| s.to_str()) == Some("asm");
+        let msvc = self.get_target().contains("msvc");
+        let (mut cmd, name) = if msvc && is_asm {
+            self.msvc_macro_assembler()
+        } else {
+            let compiler = self.get_compiler();
+            let mut cmd = compiler.to_command();
+            for &(ref a, ref b) in self.env.iter() {
+                cmd.env(a, b);
+            }
+            (cmd,
+             compiler.path
+                 .file_name()
+                 .unwrap()
+                 .to_string_lossy()
+                 .into_owned())
+        };
+        if msvc && is_asm {
+            cmd.arg("/Fo").arg(dst);
+        } else if msvc {
+            let mut s = OsString::from("/Fo");
+            s.push(&dst);
+            cmd.arg(s);
+        } else {
+            cmd.arg("-o").arg(&dst);
+        }
+        cmd.arg(if msvc { "/c" } else { "-c" });
+        cmd.arg(file);
+
+        run(&mut cmd, &name);
+    }
+
+    /// Run the compiler, returning the macro-expanded version of the input files.
+    ///
+    /// This is only relevant for C and C++ files.
+    pub fn expand(&self) -> Vec<u8> {
+        let compiler = self.get_compiler();
+        let mut cmd = compiler.to_command();
+        for &(ref a, ref b) in self.env.iter() {
+            cmd.env(a, b);
+        }
+        cmd.arg(compiler.family.expand_flag());
+        for file in self.files.iter() {
+            cmd.arg(file);
+        }
+
+        let name = compiler.path
+            .file_name()
+            .unwrap()
+            .to_string_lossy()
+            .into_owned();
+
+        run_output(&mut cmd, &name)
+    }
+
+    /// Get the compiler that's in use for this configuration.
+    ///
+    /// This function will return a `Tool` which represents the culmination
+    /// of this configuration at a snapshot in time. The returned compiler can
+    /// be inspected (e.g. the path, arguments, environment) to forward along to
+    /// other tools, or the `to_command` method can be used to invoke the
+    /// compiler itself.
+    ///
+    /// This method will take into account all configuration such as debug
+    /// information, optimization level, include directories, defines, etc.
+    /// Additionally, the compiler binary in use follows the standard
+    /// conventions for this path, e.g. looking at the explicitly set compiler,
+    /// environment variables (a number of which are inspected here), and then
+    /// falling back to the default configuration.
+    pub fn get_compiler(&self) -> Tool {
+        let opt_level = self.get_opt_level();
+        let target = self.get_target();
+
+        let mut cmd = self.get_base_compiler();
+        let nvcc = cmd.path.file_name()
+            .and_then(|p| p.to_str()).map(|p| p.contains("nvcc"))
+            .unwrap_or(false);
+
+        // Non-target flags
+        // If the flag is not conditioned on target variable, it belongs here :)
+        match cmd.family {
+            ToolFamily::Msvc => {
+                cmd.args.push("/nologo".into());
+                let features = env::var("CARGO_CFG_TARGET_FEATURE")
+                                  .unwrap_or(String::new());
+                if features.contains("crt-static") {
+                    cmd.args.push("/MT".into());
+                } else {
+                    cmd.args.push("/MD".into());
+                }
+                match &opt_level[..] {
+                    "z" | "s" => cmd.args.push("/Os".into()),
+                    "1" => cmd.args.push("/O1".into()),
+                    // -O3 is a valid value for gcc and clang compilers, but not msvc. Cap to /O2.
+                    "2" | "3" => cmd.args.push("/O2".into()),
+                    _ => {}
+                }
+            }
+            ToolFamily::Gnu |
+            ToolFamily::Clang => {
+                cmd.args.push(format!("-O{}", opt_level).into());
+                if !nvcc {
+                    cmd.args.push("-ffunction-sections".into());
+                    cmd.args.push("-fdata-sections".into());
+                    if self.pic.unwrap_or(!target.contains("windows-gnu")) {
+                        cmd.args.push("-fPIC".into());
+                    }
+                } else if self.pic.unwrap_or(false) {
+                    cmd.args.push("-Xcompiler".into());
+                    cmd.args.push("\'-fPIC\'".into());
+                }
+            }
+        }
+        for arg in self.envflags(if self.cpp {"CXXFLAGS"} else {"CFLAGS"}) {
+            cmd.args.push(arg.into());
+        }
+
+        if self.get_debug() {
+            cmd.args.push(cmd.family.debug_flag().into());
+        }
+
+        // Target flags
+        match cmd.family {
+            ToolFamily::Clang => {
+                cmd.args.push(format!("--target={}", target).into());
+            }
+            ToolFamily::Msvc => {
+                if target.contains("i586") {
+                    cmd.args.push("/ARCH:IA32".into());
+                }
+            }
+            ToolFamily::Gnu => {
+                if target.contains("i686") || target.contains("i586") {
+                    cmd.args.push("-m32".into());
+                } else if target.contains("x86_64") || target.contains("powerpc64") {
+                    cmd.args.push("-m64".into());
+                }
+
+                if target.contains("musl") {
+                    cmd.args.push("-static".into());
+                }
+
+                // armv7 targets get to use armv7 instructions
+                if target.starts_with("armv7-unknown-linux-") {
+                    cmd.args.push("-march=armv7-a".into());
+                }
+
+                // On android we can guarantee some extra float instructions
+                // (specified in the android spec online)
+                if target.starts_with("armv7-linux-androideabi") {
+                    cmd.args.push("-march=armv7-a".into());
+                    cmd.args.push("-mfpu=vfpv3-d16".into());
+                }
+
+                // For us arm == armv6 by default
+                if target.starts_with("arm-unknown-linux-") {
+                    cmd.args.push("-march=armv6".into());
+                    cmd.args.push("-marm".into());
+                }
+
+                // Turn codegen down on i586 to avoid some instructions.
+                if target.starts_with("i586-unknown-linux-") {
+                    cmd.args.push("-march=pentium".into());
+                }
+
+                // Set codegen level for i686 correctly
+                if target.starts_with("i686-unknown-linux-") {
+                    cmd.args.push("-march=i686".into());
+                }
+
+                // Looks like `musl-gcc` makes is hard for `-m32` to make its way
+                // all the way to the linker, so we need to actually instruct the
+                // linker that we're generating 32-bit executables as well. This'll
+                // typically only be used for build scripts which transitively use
+                // these flags that try to compile executables.
+                if target == "i686-unknown-linux-musl" {
+                    cmd.args.push("-Wl,-melf_i386".into());
+                }
+
+                if target.starts_with("thumb") {
+                    cmd.args.push("-mthumb".into());
+
+                    if target.ends_with("eabihf") {
+                        cmd.args.push("-mfloat-abi=hard".into())
+                    }
+                }
+                if target.starts_with("thumbv6m") {
+                    cmd.args.push("-march=armv6s-m".into());
+                }
+                if target.starts_with("thumbv7em") {
+                    cmd.args.push("-march=armv7e-m".into());
+
+                    if target.ends_with("eabihf") {
+                        cmd.args.push("-mfpu=fpv4-sp-d16".into())
+                    }
+                }
+                if target.starts_with("thumbv7m") {
+                    cmd.args.push("-march=armv7-m".into());
+                }
+            }
+        }
+
+        if target.contains("-ios") {
+            // FIXME: potential bug. iOS is always compiled with Clang, but Gcc compiler may be
+            // detected instead.
+            self.ios_flags(&mut cmd);
+        }
+
+        if self.cpp {
+            match (self.cpp_set_stdlib.as_ref(), cmd.family) {
+                (None, _) => { }
+                (Some(stdlib), ToolFamily::Gnu) |
+                (Some(stdlib), ToolFamily::Clang) => {
+                    cmd.args.push(format!("-stdlib=lib{}", stdlib).into());
+                }
+                _ => {
+                    println!("cargo:warning=cpp_set_stdlib is specified, but the {:?} compiler \
+                              does not support this option, ignored", cmd.family);
+                }
+            }
+        }
+
+        for directory in self.include_directories.iter() {
+            cmd.args.push(cmd.family.include_flag().into());
+            cmd.args.push(directory.into());
+        }
+
+        for flag in self.flags.iter() {
+            cmd.args.push(flag.into());
+        }
+
+        for &(ref key, ref value) in self.definitions.iter() {
+            let lead = if let ToolFamily::Msvc = cmd.family {"/"} else {"-"};
+            if let &Some(ref value) = value {
+                cmd.args.push(format!("{}D{}={}", lead, key, value).into());
+            } else {
+                cmd.args.push(format!("{}D{}", lead, key).into());
+            }
+        }
+        cmd
+    }
+
+    fn msvc_macro_assembler(&self) -> (Command, String) {
+        let target = self.get_target();
+        let tool = if target.contains("x86_64") {
+            "ml64.exe"
+        } else {
+            "ml.exe"
+        };
+        let mut cmd = windows_registry::find(&target, tool).unwrap_or_else(|| self.cmd(tool));
+        for directory in self.include_directories.iter() {
+            cmd.arg("/I").arg(directory);
+        }
+        for &(ref key, ref value) in self.definitions.iter() {
+            if let &Some(ref value) = value {
+                cmd.arg(&format!("/D{}={}", key, value));
+            } else {
+                cmd.arg(&format!("/D{}", key));
+            }
+        }
+
+        if target.contains("i686") || target.contains("i586") {
+            cmd.arg("/safeseh");
+        }
+        for flag in self.flags.iter() {
+            cmd.arg(flag);
+        }
+
+        (cmd, tool.to_string())
+    }
+
+    fn assemble(&self, lib_name: &str, dst: &Path, objects: &[PathBuf]) {
+        // Delete the destination if it exists as the `ar` tool at least on Unix
+        // appends to it, which we don't want.
+        let _ = fs::remove_file(&dst);
+
+        let target = self.get_target();
+        if target.contains("msvc") {
+            let mut cmd = match self.archiver {
+                Some(ref s) => self.cmd(s),
+                None => windows_registry::find(&target, "lib.exe").unwrap_or(self.cmd("lib.exe")),
+            };
+            let mut out = OsString::from("/OUT:");
+            out.push(dst);
+            run(cmd.arg(out)
+                    .arg("/nologo")
+                    .args(objects)
+                    .args(&self.objects),
+                "lib.exe");
+
+            // The Rust compiler will look for libfoo.a and foo.lib, but the
+            // MSVC linker will also be passed foo.lib, so be sure that both
+            // exist for now.
+            let lib_dst = dst.with_file_name(format!("{}.lib", lib_name));
+            let _ = fs::remove_file(&lib_dst);
+            fs::hard_link(&dst, &lib_dst)
+                .or_else(|_| {
+                    // if hard-link fails, just copy (ignoring the number of bytes written)
+                    fs::copy(&dst, &lib_dst).map(|_| ())
+                })
+                .ok()
+                .expect("Copying from {:?} to {:?} failed.");;
+        } else {
+            let ar = self.get_ar();
+            let cmd = ar.file_name().unwrap().to_string_lossy();
+            run(self.cmd(&ar)
+                    .arg("crs")
+                    .arg(dst)
+                    .args(objects)
+                    .args(&self.objects),
+                &cmd);
+        }
+    }
+
+    fn ios_flags(&self, cmd: &mut Tool) {
+        enum ArchSpec {
+            Device(&'static str),
+            Simulator(&'static str),
+        }
+
+        let target = self.get_target();
+        let arch = target.split('-').nth(0).unwrap();
+        let arch = match arch {
+            "arm" | "armv7" | "thumbv7" => ArchSpec::Device("armv7"),
+            "armv7s" | "thumbv7s" => ArchSpec::Device("armv7s"),
+            "arm64" | "aarch64" => ArchSpec::Device("arm64"),
+            "i386" | "i686" => ArchSpec::Simulator("-m32"),
+            "x86_64" => ArchSpec::Simulator("-m64"),
+            _ => fail("Unknown arch for iOS target"),
+        };
+
+        let sdk = match arch {
+            ArchSpec::Device(arch) => {
+                cmd.args.push("-arch".into());
+                cmd.args.push(arch.into());
+                cmd.args.push("-miphoneos-version-min=7.0".into());
+                "iphoneos"
+            }
+            ArchSpec::Simulator(arch) => {
+                cmd.args.push(arch.into());
+                cmd.args.push("-mios-simulator-version-min=7.0".into());
+                "iphonesimulator"
+            }
+        };
+
+        self.print(&format!("Detecting iOS SDK path for {}", sdk));
+        let sdk_path = self.cmd("xcrun")
+            .arg("--show-sdk-path")
+            .arg("--sdk")
+            .arg(sdk)
+            .stderr(Stdio::inherit())
+            .output()
+            .unwrap()
+            .stdout;
+
+        let sdk_path = String::from_utf8(sdk_path).unwrap();
+
+        cmd.args.push("-isysroot".into());
+        cmd.args.push(sdk_path.trim().into());
+    }
+
+    fn cmd<P: AsRef<OsStr>>(&self, prog: P) -> Command {
+        let mut cmd = Command::new(prog);
+        for &(ref a, ref b) in self.env.iter() {
+            cmd.env(a, b);
+        }
+        return cmd;
+    }
+
+    fn get_base_compiler(&self) -> Tool {
+        if let Some(ref c) = self.compiler {
+            return Tool::new(c.clone());
+        }
+        let host = self.get_host();
+        let target = self.get_target();
+        let (env, msvc, gnu) = if self.cpp {
+            ("CXX", "cl.exe", "g++")
+        } else {
+            ("CC", "cl.exe", "gcc")
+        };
+
+        let default = if host.contains("solaris") {
+            // In this case, c++/cc unlikely to exist or be correct.
+            gnu
+        } else if self.cpp {
+            "c++"
+        } else {
+            "cc"
+        };
+
+        self.env_tool(env)
+            .map(|(tool, args)| {
+                let mut t = Tool::new(PathBuf::from(tool));
+                for arg in args {
+                    t.args.push(arg.into());
+                }
+                return t;
+            })
+            .or_else(|| {
+                if target.contains("emscripten") {
+                    if self.cpp {
+                        Some(Tool::new(PathBuf::from("em++")))
+                    } else {
+                        Some(Tool::new(PathBuf::from("emcc")))
+                    }
+                } else {
+                    None
+                }
+            })
+            .or_else(|| windows_registry::find_tool(&target, "cl.exe"))
+            .unwrap_or_else(|| {
+                let compiler = if host.contains("windows") && target.contains("windows") {
+                    if target.contains("msvc") {
+                        msvc.to_string()
+                    } else {
+                        format!("{}.exe", gnu)
+                    }
+                } else if target.contains("android") {
+                    format!("{}-{}", target.replace("armv7", "arm"), gnu)
+                } else if self.get_host() != target {
+                    // CROSS_COMPILE is of the form: "arm-linux-gnueabi-"
+                    let cc_env = self.getenv("CROSS_COMPILE");
+                    let cross_compile = cc_env.as_ref().map(|s| s.trim_right_matches('-'));
+                    let prefix = cross_compile.or(match &target[..] {
+                        "aarch64-unknown-linux-gnu" => Some("aarch64-linux-gnu"),
+                        "arm-unknown-linux-gnueabi" => Some("arm-linux-gnueabi"),
+                        "arm-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
+                        "arm-unknown-linux-musleabi" => Some("arm-linux-musleabi"),
+                        "arm-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
+                        "arm-unknown-netbsdelf-eabi" => Some("arm--netbsdelf-eabi"),
+                        "armv6-unknown-netbsdelf-eabihf" => Some("armv6--netbsdelf-eabihf"),
+                        "armv7-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
+                        "armv7-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
+                        "armv7-unknown-netbsdelf-eabihf" => Some("armv7--netbsdelf-eabihf"),
+                        "i686-pc-windows-gnu" => Some("i686-w64-mingw32"),
+                        "i686-unknown-linux-musl" => Some("musl"),
+                        "i686-unknown-netbsdelf" => Some("i486--netbsdelf"),
+                        "mips-unknown-linux-gnu" => Some("mips-linux-gnu"),
+                        "mipsel-unknown-linux-gnu" => Some("mipsel-linux-gnu"),
+                        "mips64-unknown-linux-gnuabi64" => Some("mips64-linux-gnuabi64"),
+                        "mips64el-unknown-linux-gnuabi64" => Some("mips64el-linux-gnuabi64"),
+                        "powerpc-unknown-linux-gnu" => Some("powerpc-linux-gnu"),
+                        "powerpc-unknown-netbsd" => Some("powerpc--netbsd"),
+                        "powerpc64-unknown-linux-gnu" => Some("powerpc-linux-gnu"),
+                        "powerpc64le-unknown-linux-gnu" => Some("powerpc64le-linux-gnu"),
+                        "s390x-unknown-linux-gnu" => Some("s390x-linux-gnu"),
+                        "sparc64-unknown-netbsd" => Some("sparc64--netbsd"),
+                        "sparcv9-sun-solaris" => Some("sparcv9-sun-solaris"),
+                        "thumbv6m-none-eabi" => Some("arm-none-eabi"),
+                        "thumbv7em-none-eabi" => Some("arm-none-eabi"),
+                        "thumbv7em-none-eabihf" => Some("arm-none-eabi"),
+                        "thumbv7m-none-eabi" => Some("arm-none-eabi"),
+                        "x86_64-pc-windows-gnu" => Some("x86_64-w64-mingw32"),
+                        "x86_64-rumprun-netbsd" => Some("x86_64-rumprun-netbsd"),
+                        "x86_64-unknown-linux-musl" => Some("musl"),
+                        "x86_64-unknown-netbsd" => Some("x86_64--netbsd"),
+                        _ => None,
+                    });
+                    match prefix {
+                        Some(prefix) => format!("{}-{}", prefix, gnu),
+                        None => default.to_string(),
+                    }
+                } else {
+                    default.to_string()
+                };
+                Tool::new(PathBuf::from(compiler))
+            })
+    }
+
+    fn get_var(&self, var_base: &str) -> Result<String, String> {
+        let target = self.get_target();
+        let host = self.get_host();
+        let kind = if host == target { "HOST" } else { "TARGET" };
+        let target_u = target.replace("-", "_");
+        let res = self.getenv(&format!("{}_{}", var_base, target))
+            .or_else(|| self.getenv(&format!("{}_{}", var_base, target_u)))
+            .or_else(|| self.getenv(&format!("{}_{}", kind, var_base)))
+            .or_else(|| self.getenv(var_base));
+
+        match res {
+            Some(res) => Ok(res),
+            None => Err("could not get environment variable".to_string()),
+        }
+    }
+
+    fn envflags(&self, name: &str) -> Vec<String> {
+        self.get_var(name)
+            .unwrap_or(String::new())
+            .split(|c: char| c.is_whitespace())
+            .filter(|s| !s.is_empty())
+            .map(|s| s.to_string())
+            .collect()
+    }
+
+    fn env_tool(&self, name: &str) -> Option<(String, Vec<String>)> {
+        self.get_var(name).ok().map(|tool| {
+            let whitelist = ["ccache", "distcc"];
+            for t in whitelist.iter() {
+                if tool.starts_with(t) && tool[t.len()..].starts_with(" ") {
+                    return (t.to_string(), vec![tool[t.len()..].trim_left().to_string()]);
+                }
+            }
+            (tool, Vec::new())
+        })
+    }
+
+    /// Returns the default C++ standard library for the current target: `libc++`
+    /// for OS X and `libstdc++` for anything else.
+    fn get_cpp_link_stdlib(&self) -> Option<String> {
+        self.cpp_link_stdlib.clone().unwrap_or_else(|| {
+            let target = self.get_target();
+            if target.contains("msvc") {
+                None
+            } else if target.contains("darwin") {
+                Some("c++".to_string())
+            } else if target.contains("freebsd") {
+                Some("c++".to_string())
+            } else {
+                Some("stdc++".to_string())
+            }
+        })
+    }
+
+    fn get_ar(&self) -> PathBuf {
+        self.archiver
+            .clone()
+            .or_else(|| self.get_var("AR").map(PathBuf::from).ok())
+            .unwrap_or_else(|| {
+                if self.get_target().contains("android") {
+                    PathBuf::from(format!("{}-ar", self.get_target().replace("armv7", "arm")))
+                } else if self.get_target().contains("emscripten") {
+                    PathBuf::from("emar")
+                } else {
+                    PathBuf::from("ar")
+                }
+            })
+    }
+
+    fn get_target(&self) -> String {
+        self.target.clone().unwrap_or_else(|| self.getenv_unwrap("TARGET"))
+    }
+
+    fn get_host(&self) -> String {
+        self.host.clone().unwrap_or_else(|| self.getenv_unwrap("HOST"))
+    }
+
+    fn get_opt_level(&self) -> String {
+        self.opt_level.as_ref().cloned().unwrap_or_else(|| self.getenv_unwrap("OPT_LEVEL"))
+    }
+
+    fn get_debug(&self) -> bool {
+        self.debug.unwrap_or_else(|| self.getenv_unwrap("PROFILE") == "debug")
+    }
+
+    fn get_out_dir(&self) -> PathBuf {
+        self.out_dir.clone().unwrap_or_else(|| env::var_os("OUT_DIR").map(PathBuf::from).unwrap())
+    }
+
+    fn getenv(&self, v: &str) -> Option<String> {
+        let r = env::var(v).ok();
+        self.print(&format!("{} = {:?}", v, r));
+        r
+    }
+
+    fn getenv_unwrap(&self, v: &str) -> String {
+        match self.getenv(v) {
+            Some(s) => s,
+            None => fail(&format!("environment variable `{}` not defined", v)),
+        }
+    }
+
+    fn print(&self, s: &str) {
+        if self.cargo_metadata {
+            println!("{}", s);
+        }
+    }
+}
+
+impl Tool {
+    fn new(path: PathBuf) -> Tool {
+        // Try to detect family of the tool from its name, falling back to Gnu.
+        let family = if let Some(fname) = path.file_name().and_then(|p| p.to_str()) {
+            if fname.contains("clang") {
+                ToolFamily::Clang
+            } else if fname.contains("cl") {
+                ToolFamily::Msvc
+            } else {
+                ToolFamily::Gnu
+            }
+        } else {
+            ToolFamily::Gnu
+        };
+        Tool {
+            path: path,
+            args: Vec::new(),
+            env: Vec::new(),
+            family: family
+        }
+    }
+
+    /// Converts this compiler into a `Command` that's ready to be run.
+    ///
+    /// This is useful for when the compiler needs to be executed and the
+    /// command returned will already have the initial arguments and environment
+    /// variables configured.
+    pub fn to_command(&self) -> Command {
+        let mut cmd = Command::new(&self.path);
+        cmd.args(&self.args);
+        for &(ref k, ref v) in self.env.iter() {
+            cmd.env(k, v);
+        }
+        cmd
+    }
+
+    /// Returns the path for this compiler.
+    ///
+    /// Note that this may not be a path to a file on the filesystem, e.g. "cc",
+    /// but rather something which will be resolved when a process is spawned.
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
+    /// Returns the default set of arguments to the compiler needed to produce
+    /// executables for the target this compiler generates.
+    pub fn args(&self) -> &[OsString] {
+        &self.args
+    }
+
+    /// Returns the set of environment variables needed for this compiler to
+    /// operate.
+    ///
+    /// This is typically only used for MSVC compilers currently.
+    pub fn env(&self) -> &[(OsString, OsString)] {
+        &self.env
+    }
+}
+
+fn run(cmd: &mut Command, program: &str) {
+    let (mut child, print) = spawn(cmd, program);
+    let status = child.wait().expect("failed to wait on child process");
+    print.join().unwrap();
+    println!("{:?}", status);
+    if !status.success() {
+        fail(&format!("command did not execute successfully, got: {}", status));
+    }
+}
+
+fn run_output(cmd: &mut Command, program: &str) -> Vec<u8> {
+    cmd.stdout(Stdio::piped());
+    let (mut child, print) = spawn(cmd, program);
+    let mut stdout = vec![];
+    child.stdout.take().unwrap().read_to_end(&mut stdout).unwrap();
+    let status = child.wait().expect("failed to wait on child process");
+    print.join().unwrap();
+    println!("{:?}", status);
+    if !status.success() {
+        fail(&format!("command did not execute successfully, got: {}", status));
+    }
+    return stdout
+}
+
+fn spawn(cmd: &mut Command, program: &str) -> (Child, JoinHandle<()>) {
+    println!("running: {:?}", cmd);
+
+    // Capture the standard error coming from these programs, and write it out
+    // with cargo:warning= prefixes. Note that this is a bit wonky to avoid
+    // requiring the output to be UTF-8, we instead just ship bytes from one
+    // location to another.
+    match cmd.stderr(Stdio::piped()).spawn() {
+        Ok(mut child) => {
+            let stderr = BufReader::new(child.stderr.take().unwrap());
+            let print = thread::spawn(move || {
+                for line in stderr.split(b'\n').filter_map(|l| l.ok()) {
+                    print!("cargo:warning=");
+                    std::io::stdout().write_all(&line).unwrap();
+                    println!("");
+                }
+            });
+            (child, print)
+        }
+        Err(ref e) if e.kind() == io::ErrorKind::NotFound => {
+            let extra = if cfg!(windows) {
+                " (see https://github.com/alexcrichton/gcc-rs#compile-time-requirements \
+                   for help)"
+            } else {
+                ""
+            };
+            fail(&format!("failed to execute command: {}\nIs `{}` \
+                           not installed?{}",
+                          e,
+                          program,
+                          extra));
+        }
+        Err(e) => fail(&format!("failed to execute command: {}", e)),
+    }
+}
+
+fn fail(s: &str) -> ! {
+    println!("\n\n{}\n\n", s);
+    panic!()
+}