Update cc crate to 1.0.48

This change updates the cc crate to version 1.0.48.

Import subrepo cc/:cc at be9f2c1ae05b336aa3d07a4cbefdc1d88a3d8a91

4 files changed, 346 insertions, 119 deletions

diff --git a/cc/src/com.rs b/cc/src/com.rs
index 9b75d47..a5f2afe 100644
--- a/cc/src/com.rs
+++ b/cc/src/com.rs
@@ -7,19 +7,19 @@
 
 #![allow(unused)]
 
+use crate::winapi::CoInitializeEx;
+use crate::winapi::IUnknown;
+use crate::winapi::Interface;
+use crate::winapi::BSTR;
+use crate::winapi::COINIT_MULTITHREADED;
+use crate::winapi::{SysFreeString, SysStringLen};
+use crate::winapi::{HRESULT, S_FALSE, S_OK};
 use std::ffi::{OsStr, OsString};
 use std::mem::forget;
 use std::ops::Deref;
 use std::os::windows::ffi::{OsStrExt, OsStringExt};
 use std::ptr::null_mut;
 use std::slice::from_raw_parts;
-use winapi::CoInitializeEx;
-use winapi::IUnknown;
-use winapi::Interface;
-use winapi::BSTR;
-use winapi::COINIT_MULTITHREADED;
-use winapi::{SysFreeString, SysStringLen};
-use winapi::{HRESULT, S_FALSE, S_OK};
 
 pub fn initialize() -> Result<(), HRESULT> {
     let err = unsafe { CoInitializeEx(null_mut(), COINIT_MULTITHREADED) };
diff --git a/cc/src/lib.rs b/cc/src/lib.rs
index 2d918b8..d795e5a 100644
--- a/cc/src/lib.rs
+++ b/cc/src/lib.rs
@@ -35,15 +35,13 @@
 //! Cargo will also set this environment variable when executed with the `-jN` flag.
 //!
 //! If `NUM_JOBS` is not set, the `RAYON_NUM_THREADS` environment variable can
-//! also specify the build paralellism.
+//! also specify the build parallelism.
 //!
 //! # Examples
 //!
 //! Use the `Build` struct to compile `src/foo.c`:
 //!
 //! ```no_run
-//! extern crate cc;
-//!
 //! fn main() {
 //!     cc::Build::new()
 //!         .file("src/foo.c")
@@ -58,9 +56,6 @@
 #![allow(deprecated)]
 #![deny(missing_docs)]
 
-#[cfg(feature = "parallel")]
-extern crate rayon;
-
 use std::collections::HashMap;
 use std::env;
 use std::ffi::{OsStr, OsString};
@@ -99,6 +94,8 @@ pub struct Build {
     flags: Vec<String>,
     flags_supported: Vec<String>,
     known_flag_support_status: Arc<Mutex<HashMap<String, bool>>>,
+    ar_flags: Vec<String>,
+    no_default_flags: bool,
     files: Vec<PathBuf>,
     cpp: bool,
     cpp_link_stdlib: Option<Option<String>>,
@@ -109,6 +106,7 @@ pub struct Build {
     out_dir: Option<PathBuf>,
     opt_level: Option<String>,
     debug: Option<bool>,
+    force_frame_pointer: Option<bool>,
     env: Vec<(OsString, OsString)>,
     compiler: Option<PathBuf>,
     archiver: Option<PathBuf>,
@@ -213,8 +211,17 @@ impl ToolFamily {
             }
             ToolFamily::Gnu | ToolFamily::Clang => {
                 cmd.push_cc_arg("-g".into());
+            }
+        }
+    }
+
+    /// What the flag to force frame pointers.
+    fn add_force_frame_pointer(&self, cmd: &mut Tool) {
+        match *self {
+            ToolFamily::Gnu | ToolFamily::Clang => {
                 cmd.push_cc_arg("-fno-omit-frame-pointer".into());
             }
+            _ => (),
         }
     }
 
@@ -277,6 +284,8 @@ impl Build {
             flags: Vec::new(),
             flags_supported: Vec::new(),
             known_flag_support_status: Arc::new(Mutex::new(HashMap::new())),
+            ar_flags: Vec::new(),
+            no_default_flags: false,
             files: Vec::new(),
             shared_flag: None,
             static_flag: None,
@@ -289,6 +298,7 @@ impl Build {
             out_dir: None,
             opt_level: None,
             debug: None,
+            force_frame_pointer: None,
             env: Vec::new(),
             compiler: None,
             archiver: None,
@@ -361,6 +371,23 @@ impl Build {
         self
     }
 
+    /// Add an arbitrary flag to the invocation of the compiler
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// cc::Build::new()
+    ///     .file("src/foo.c")
+    ///     .file("src/bar.c")
+    ///     .ar_flag("/NODEFAULTLIB:libc.dll")
+    ///     .compile("foo");
+    /// ```
+
+    pub fn ar_flag(&mut self, flag: &str) -> &mut Build {
+        self.ar_flags.push(flag.to_string());
+        self
+    }
+
     fn ensure_check_file(&self) -> Result<PathBuf, Error> {
         let out_dir = self.get_out_dir()?;
         let src = if self.cuda {
@@ -497,6 +524,17 @@ impl Build {
         self
     }
 
+    /// Disables the generation of default compiler flags. The default compiler
+    /// flags may cause conflicts in some cross compiling scenarios.
+    ///
+    /// Setting the `CRATE_CC_NO_DEFAULTS` environment variable has the same
+    /// effect as setting this to `true`. The presence of the environment
+    /// variable and the value of `no_default_flags` will be OR'd together.
+    pub fn no_default_flags(&mut self, no_default_flags: bool) -> &mut Build {
+        self.no_default_flags = no_default_flags;
+        self
+    }
+
     /// Add a file which will be compiled
     pub fn file<P: AsRef<Path>>(&mut self, p: P) -> &mut Build {
         self.files.push(p.as_ref().to_path_buf());
@@ -750,6 +788,17 @@ impl Build {
         self
     }
 
+    /// Configures whether the compiler will emit instructions to store
+    /// frame pointers during codegen.
+    ///
+    /// This option is automatically enabled when debug information is emitted.
+    /// Otherwise the target platform compiler's default will be used.
+    /// You can use this option to force a specific setting.
+    pub fn force_frame_pointer(&mut self, force: bool) -> &mut Build {
+        self.force_frame_pointer = Some(force);
+        self
+    }
+
     /// Configures the output directory where all object files and static
     /// libraries will be located.
     ///
@@ -931,22 +980,150 @@ impl Build {
     }
 
     #[cfg(feature = "parallel")]
-    fn compile_objects(&self, objs: &[Object]) -> Result<(), Error> {
-        use self::rayon::prelude::*;
+    fn compile_objects<'me>(&'me self, objs: &[Object]) -> Result<(), Error> {
+        use std::sync::atomic::{AtomicBool, Ordering::SeqCst};
+        use std::sync::Once;
+
+        // Limit our parallelism globally with a jobserver. Start off by
+        // releasing our own token for this process so we can have a bit of an
+        // easier to write loop below. If this fails, though, then we're likely
+        // on Windows with the main implicit token, so we just have a bit extra
+        // parallelism for a bit and don't reacquire later.
+        let server = jobserver();
+        let reacquire = server.release_raw().is_ok();
+
+        // When compiling objects in parallel we do a few dirty tricks to speed
+        // things up:
+        //
+        // * First is that we use the `jobserver` crate to limit the parallelism
+        //   of this build script. The `jobserver` crate will use a jobserver
+        //   configured by Cargo for build scripts to ensure that parallelism is
+        //   coordinated across C compilations and Rust compilations. Before we
+        //   compile anything we make sure to wait until we acquire a token.
+        //
+        //   Note that this jobserver is cached globally so we only used one per
+        //   process and only worry about creating it once.
+        //
+        // * Next we use a raw `thread::spawn` per thread to actually compile
+        //   objects in parallel. We only actually spawn a thread after we've
+        //   acquired a token to perform some work
+        //
+        // * Finally though we want to keep the dependencies of this crate
+        //   pretty light, so we avoid using a safe abstraction like `rayon` and
+        //   instead rely on some bits of `unsafe` code. We know that this stack
+        //   frame persists while everything is compiling so we use all the
+        //   stack-allocated objects without cloning/reallocating. We use a
+        //   transmute to `State` with a `'static` lifetime to persist
+        //   everything we need across the boundary, and the join-on-drop
+        //   semantics of `JoinOnDrop` should ensure that our stack frame is
+        //   alive while threads are alive.
+        //
+        // With all that in mind we compile all objects in a loop here, after we
+        // acquire the appropriate tokens, Once all objects have been compiled
+        // we join on all the threads and propagate the results of compilation.
+        //
+        // Note that as a slight optimization we try to break out as soon as
+        // possible as soon as any compilation fails to ensure that errors get
+        // out to the user as fast as possible.
+        let error = AtomicBool::new(false);
+        let mut threads = Vec::new();
+        for obj in objs {
+            if error.load(SeqCst) {
+                break;
+            }
+            let token = server.acquire()?;
+            let state = State {
+                build: self,
+                obj,
+                error: &error,
+            };
+            let state = unsafe { std::mem::transmute::<State, State<'static>>(state) };
+            let thread = thread::spawn(|| {
+                let state: State<'me> = state; // erase the `'static` lifetime
+                let result = state.build.compile_object(state.obj);
+                if result.is_err() {
+                    state.error.store(true, SeqCst);
+                }
+                drop(token); // make sure our jobserver token is released after the compile
+                return result;
+            });
+            threads.push(JoinOnDrop(Some(thread)));
+        }
 
-        if let Some(amt) = self.getenv("NUM_JOBS") {
-            if let Ok(amt) = amt.parse() {
-                let _ = rayon::ThreadPoolBuilder::new()
-                    .num_threads(amt)
-                    .build_global();
+        for mut thread in threads {
+            if let Some(thread) = thread.0.take() {
+                thread.join().expect("thread should not panic")?;
             }
         }
 
-        // Check for any errors and return the first one found.
-        objs.par_iter()
-            .with_max_len(1)
-            .map(|obj| self.compile_object(obj))
-            .collect()
+        // Reacquire our process's token before we proceed, which we released
+        // before entering the loop above.
+        if reacquire {
+            server.acquire_raw()?;
+        }
+
+        return Ok(());
+
+        /// Shared state from the parent thread to the child thread. This
+        /// package of pointers is temporarily transmuted to a `'static`
+        /// lifetime to cross the thread boundary and then once the thread is
+        /// running we erase the `'static` to go back to an anonymous lifetime.
+        struct State<'a> {
+            build: &'a Build,
+            obj: &'a Object,
+            error: &'a AtomicBool,
+        }
+
+        /// Returns a suitable `jobserver::Client` used to coordinate
+        /// parallelism between build scripts.
+        fn jobserver() -> &'static jobserver::Client {
+            static INIT: Once = Once::new();
+            static mut JOBSERVER: Option<jobserver::Client> = None;
+
+            fn _assert_sync<T: Sync>() {}
+            _assert_sync::<jobserver::Client>();
+
+            unsafe {
+                INIT.call_once(|| {
+                    let server = default_jobserver();
+                    JOBSERVER = Some(server);
+                });
+                JOBSERVER.as_ref().unwrap()
+            }
+        }
+
+        unsafe fn default_jobserver() -> jobserver::Client {
+            // Try to use the environmental jobserver which Cargo typically
+            // initializes for us...
+            if let Some(client) = jobserver::Client::from_env() {
+                return client;
+            }
+
+            // ... but if that fails for whatever reason fall back to the number
+            // of cpus on the system or the `NUM_JOBS` env var.
+            let mut parallelism = num_cpus::get();
+            if let Ok(amt) = env::var("NUM_JOBS") {
+                if let Ok(amt) = amt.parse() {
+                    parallelism = amt;
+                }
+            }
+
+            // If we create our own jobserver then be sure to reserve one token
+            // for ourselves.
+            let client = jobserver::Client::new(parallelism).expect("failed to create jobserver");
+            client.acquire_raw().expect("failed to acquire initial");
+            return client;
+        }
+
+        struct JoinOnDrop(Option<thread::JoinHandle<Result<(), Error>>>);
+
+        impl Drop for JoinOnDrop {
+            fn drop(&mut self) {
+                if let Some(thread) = self.0.take() {
+                    drop(thread.join());
+                }
+            }
+        }
     }
 
     #[cfg(not(feature = "parallel"))]
@@ -1073,11 +1250,10 @@ impl Build {
         let mut cmd = self.get_base_compiler()?;
         let envflags = self.envflags(if self.cpp { "CXXFLAGS" } else { "CFLAGS" });
 
-        // Disable default flag generation via environment variable or when
-        // certain cross compiling arguments are set
-        let use_defaults = self.getenv("CRATE_CC_NO_DEFAULTS").is_none();
+        // Disable default flag generation via `no_default_flags` or environment variable
+        let no_defaults = self.no_default_flags || self.getenv("CRATE_CC_NO_DEFAULTS").is_some();
 
-        if use_defaults {
+        if !no_defaults {
             self.add_default_flags(&mut cmd, &target, &opt_level)?;
         } else {
             println!("Info: default compiler flags are disabled");
@@ -1213,12 +1389,22 @@ impl Build {
             family.add_debug_flags(cmd);
         }
 
+        if self.get_force_frame_pointer() {
+            let family = cmd.family;
+            family.add_force_frame_pointer(cmd);
+        }
+
         // Target flags
         match cmd.family {
             ToolFamily::Clang => {
                 cmd.args.push(format!("--target={}", target).into());
             }
             ToolFamily::Msvc { clang_cl } => {
+                // This is an undocumented flag from MSVC but helps with making
+                // builds more reproducible by avoiding putting timestamps into
+                // files.
+                cmd.args.push("-Brepro".into());
+
                 if clang_cl {
                     if target.contains("x86_64") {
                         cmd.args.push("-m64".into());
@@ -1402,9 +1588,11 @@ impl Build {
                     if let Some(arch) = parts.next() {
                         let arch = &arch[5..];
                         cmd.args.push(("-march=rv".to_owned() + arch).into());
-                        // ABI is always soft-float right now, update this when this is no longer the
-                        // case:
-                        if arch.starts_with("64") {
+                        if target.contains("linux") && arch.starts_with("64") {
+                            cmd.args.push("-mabi=lp64d".into());
+                        } else if target.contains("linux") && arch.starts_with("32") {
+                            cmd.args.push("-mabi=ilp32d".into());
+                        } else if arch.starts_with("64") {
                             cmd.args.push("-mabi=lp64".into());
                         } else {
                             cmd.args.push("-mabi=ilp32".into());
@@ -1501,6 +1689,9 @@ impl Build {
             let mut out = OsString::from("-out:");
             out.push(dst);
             cmd.arg(out).arg("-nologo");
+            for flag in self.ar_flags.iter() {
+                cmd.arg(flag);
+            }
 
             // Similar to https://github.com/rust-lang/rust/pull/47507
             // and https://github.com/rust-lang/rust/pull/48548
@@ -1563,6 +1754,33 @@ impl Build {
             };
         } else {
             let (mut ar, cmd) = self.get_ar()?;
+
+            // Set an environment variable to tell the OSX archiver to ensure
+            // that all dates listed in the archive are zero, improving
+            // determinism of builds. AFAIK there's not really official
+            // documentation of this but there's a lot of references to it if
+            // you search google.
+            //
+            // You can reproduce this locally on a mac with:
+            //
+            //      $ touch foo.c
+            //      $ cc -c foo.c -o foo.o
+            //
+            //      # Notice that these two checksums are different
+            //      $ ar crus libfoo1.a foo.o && sleep 2 && ar crus libfoo2.a foo.o
+            //      $ md5sum libfoo*.a
+            //
+            //      # Notice that these two checksums are the same
+            //      $ export ZERO_AR_DATE=1
+            //      $ ar crus libfoo1.a foo.o && sleep 2 && touch foo.o && ar crus libfoo2.a foo.o
+            //      $ md5sum libfoo*.a
+            //
+            // In any case if this doesn't end up getting read, it shouldn't
+            // cause that many issues!
+            ar.env("ZERO_AR_DATE", "1");
+            for flag in self.ar_flags.iter() {
+                ar.arg(flag);
+            }
             run(
                 ar.arg("crs").arg(dst).args(&objects).args(&self.objects),
                 &cmd,
@@ -1687,13 +1905,19 @@ impl Build {
 
         let tool_opt: Option<Tool> = self
             .env_tool(env)
-            .map(|(tool, cc, args)| {
+            .map(|(tool, wrapper, args)| {
+                // find the driver mode, if any
+                const DRIVER_MODE: &str = "--driver-mode=";
+                let driver_mode = args
+                    .iter()
+                    .find(|a| a.starts_with(DRIVER_MODE))
+                    .map(|a| &a[DRIVER_MODE.len()..]);
                 // chop off leading/trailing whitespace to work around
                 // semi-buggy build scripts which are shared in
                 // makefiles/configure scripts (where spaces are far more
                 // lenient)
-                let mut t = Tool::new(PathBuf::from(tool.trim()));
-                if let Some(cc) = cc {
+                let mut t = Tool::with_clang_driver(PathBuf::from(tool.trim()), driver_mode);
+                if let Some(cc) = wrapper {
                     t.cc_wrapper_path = Some(PathBuf::from(cc));
                 }
                 for arg in args {
@@ -1846,7 +2070,7 @@ impl Build {
                 Err(_) => "nvcc".into(),
                 Ok(nvcc) => nvcc,
             };
-            let mut nvcc_tool = Tool::with_features(PathBuf::from(nvcc), self.cuda);
+            let mut nvcc_tool = Tool::with_features(PathBuf::from(nvcc), None, self.cuda);
             nvcc_tool
                 .args
                 .push(format!("-ccbin={}", tool.path.display()).into());
@@ -2062,6 +2286,10 @@ impl Build {
         })
     }
 
+    fn get_force_frame_pointer(&self) -> bool {
+        self.force_frame_pointer.unwrap_or_else(|| self.get_debug())
+    }
+
     fn get_out_dir(&self) -> Result<PathBuf, Error> {
         match self.out_dir.clone() {
             Some(p) => Ok(p),
@@ -2109,11 +2337,15 @@ impl Default for Build {
 }
 
 impl Tool {
-    fn new(path: PathBuf) -> Tool {
-        Tool::with_features(path, false)
+    fn new(path: PathBuf) -> Self {
+        Tool::with_features(path, None, false)
     }
 
-    fn with_features(path: PathBuf, cuda: bool) -> Tool {
+    fn with_clang_driver(path: PathBuf, clang_driver: Option<&str>) -> Self {
+        Self::with_features(path, clang_driver, false)
+    }
+
+    fn with_features(path: PathBuf, clang_driver: Option<&str>, cuda: bool) -> Self {
         // 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-cl") {
@@ -2125,13 +2357,17 @@ impl Tool {
             {
                 ToolFamily::Msvc { clang_cl: false }
             } else if fname.contains("clang") {
-                ToolFamily::Clang
+                match clang_driver {
+                    Some("cl") => ToolFamily::Msvc { clang_cl: true },
+                    _ => ToolFamily::Clang,
+                }
             } else {
                 ToolFamily::Gnu
             }
         } else {
             ToolFamily::Gnu
         };
+
         Tool {
             path: path,
             cc_wrapper_path: None,
diff --git a/cc/src/setup_config.rs b/cc/src/setup_config.rs
index 56fe114..bc2b1c2 100644
--- a/cc/src/setup_config.rs
+++ b/cc/src/setup_config.rs
@@ -8,19 +8,19 @@
 #![allow(bad_style)]
 #![allow(unused)]
 
+use crate::winapi::Interface;
+use crate::winapi::BSTR;
+use crate::winapi::LPCOLESTR;
+use crate::winapi::LPSAFEARRAY;
+use crate::winapi::S_FALSE;
+use crate::winapi::{CoCreateInstance, CLSCTX_ALL};
+use crate::winapi::{IUnknown, IUnknownVtbl};
+use crate::winapi::{HRESULT, LCID, LPCWSTR, PULONGLONG};
+use crate::winapi::{LPFILETIME, ULONG};
 use std::ffi::OsString;
 use std::ptr::null_mut;
-use winapi::Interface;
-use winapi::BSTR;
-use winapi::LPCOLESTR;
-use winapi::LPSAFEARRAY;
-use winapi::S_FALSE;
-use winapi::{CoCreateInstance, CLSCTX_ALL};
-use winapi::{IUnknown, IUnknownVtbl};
-use winapi::{HRESULT, LCID, LPCWSTR, PULONGLONG};
-use winapi::{LPFILETIME, ULONG};
 
-use com::{BStr, ComPtr};
+use crate::com::{BStr, ComPtr};
 
 // Bindings to the Setup.Configuration stuff
 pub type InstanceState = u32;
@@ -196,7 +196,7 @@ impl SetupConfiguration {
     }
     pub fn enum_all_instances(&self) -> Result<EnumSetupInstances, i32> {
         let mut obj = null_mut();
-        let this = try!(self.0.cast::<ISetupConfiguration2>());
+        let this = self.0.cast::<ISetupConfiguration2>()?;
         let err = unsafe { this.EnumAllInstances(&mut obj) };
         if err < 0 {
             return Err(err);
@@ -249,7 +249,7 @@ impl SetupInstance {
     }
     pub fn product_path(&self) -> Result<OsString, i32> {
         let mut s = null_mut();
-        let this = try!(self.0.cast::<ISetupInstance2>());
+        let this = self.0.cast::<ISetupInstance2>()?;
         let err = unsafe { this.GetProductPath(&mut s) };
         let bstr = unsafe { BStr::from_raw(s) };
         if err < 0 {
diff --git a/cc/src/windows_registry.rs b/cc/src/windows_registry.rs
index ee39339..5af3ff7 100644
--- a/cc/src/windows_registry.rs
+++ b/cc/src/windows_registry.rs
@@ -13,17 +13,7 @@
 
 use std::process::Command;
 
-use Tool;
-
-#[cfg(windows)]
-macro_rules! otry {
-    ($expr:expr) => {
-        match $expr {
-            Some(val) => val,
-            None => return None,
-        }
-    };
-}
+use crate::Tool;
 
 /// Attempts to find a tool within an MSVC installation using the Windows
 /// registry as a point to search from.
@@ -173,9 +163,9 @@ pub fn find_vs_version() -> Result<VsVers, String> {
 
 #[cfg(windows)]
 mod impl_ {
-    use com;
-    use registry::{RegistryKey, LOCAL_MACHINE};
-    use setup_config::{EnumSetupInstances, SetupConfiguration, SetupInstance};
+    use crate::com;
+    use crate::registry::{RegistryKey, LOCAL_MACHINE};
+    use crate::setup_config::{EnumSetupInstances, SetupConfiguration, SetupInstance};
     use std::env;
     use std::ffi::OsString;
     use std::fs::File;
@@ -184,7 +174,7 @@ mod impl_ {
     use std::mem;
     use std::path::{Path, PathBuf};
 
-    use Tool;
+    use crate::Tool;
 
     struct MsvcTool {
         tool: PathBuf,
@@ -218,6 +208,7 @@ mod impl_ {
         }
     }
 
+    #[allow(bare_trait_objects)]
     fn vs16_instances() -> Box<Iterator<Item = PathBuf>> {
         let instances = if let Some(instances) = vs15_instances() {
             instances
@@ -225,10 +216,10 @@ mod impl_ {
             return Box::new(iter::empty());
         };
         Box::new(instances.filter_map(|instance| {
-            let instance = otry!(instance.ok());
-            let installation_name = otry!(instance.installation_name().ok());
-            if otry!(installation_name.to_str()).starts_with("VisualStudio/16.") {
-                Some(PathBuf::from(otry!(instance.installation_path().ok())))
+            let instance = instance.ok()?;
+            let installation_name = instance.installation_name().ok()?;
+            if installation_name.to_str()?.starts_with("VisualStudio/16.") {
+                Some(PathBuf::from(instance.installation_path().ok()?))
             } else {
                 None
             }
@@ -263,16 +254,16 @@ mod impl_ {
     //
     // [online]: https://blogs.msdn.microsoft.com/vcblog/2017/03/06/finding-the-visual-c-compiler-tools-in-visual-studio-2017/
     fn vs15_instances() -> Option<EnumSetupInstances> {
-        otry!(com::initialize().ok());
+        com::initialize().ok()?;
 
-        let config = otry!(SetupConfiguration::new().ok());
+        let config = SetupConfiguration::new().ok()?;
         config.enum_all_instances().ok()
     }
 
     pub fn find_msvc_15(tool: &str, target: &str) -> Option<Tool> {
-        let iter = otry!(vs15_instances());
+        let iter = vs15_instances()?;
         for instance in iter {
-            let instance = otry!(instance.ok());
+            let instance = instance.ok()?;
             let tool = tool_from_vs15_instance(tool, target, &instance);
             if tool.is_some() {
                 return tool;
@@ -322,8 +313,7 @@ mod impl_ {
     }
 
     fn tool_from_vs15_instance(tool: &str, target: &str, instance: &SetupInstance) -> Option<Tool> {
-        let (bin_path, host_dylib_path, lib_path, include_path) =
-            otry!(vs15_vc_paths(target, instance));
+        let (bin_path, host_dylib_path, lib_path, include_path) = vs15_vc_paths(target, instance)?;
         let tool_path = bin_path.join(tool);
         if !tool_path.exists() {
             return None;
@@ -339,7 +329,7 @@ mod impl_ {
             tool.include.push(atl_include_path);
         }
 
-        otry!(add_sdks(&mut tool, target));
+        add_sdks(&mut tool, target)?;
 
         Some(tool.into_tool())
     }
@@ -348,19 +338,19 @@ mod impl_ {
         target: &str,
         instance: &SetupInstance,
     ) -> Option<(PathBuf, PathBuf, PathBuf, PathBuf)> {
-        let instance_path: PathBuf = otry!(instance.installation_path().ok()).into();
+        let instance_path: PathBuf = instance.installation_path().ok()?.into();
         let version_path =
             instance_path.join(r"VC\Auxiliary\Build\Microsoft.VCToolsVersion.default.txt");
-        let mut version_file = otry!(File::open(version_path).ok());
+        let mut version_file = File::open(version_path).ok()?;
         let mut version = String::new();
-        otry!(version_file.read_to_string(&mut version).ok());
+        version_file.read_to_string(&mut version).ok()?;
         let version = version.trim();
         let host = match host_arch() {
             X86 => "X86",
             X86_64 => "X64",
             _ => return None,
         };
-        let target = otry!(lib_subdir(target));
+        let target = lib_subdir(target)?;
         // The directory layout here is MSVC/bin/Host$host/$target/
         let path = instance_path.join(r"VC\Tools\MSVC").join(version);
         // This is the path to the toolchain for a particular target, running
@@ -383,7 +373,7 @@ mod impl_ {
 
     fn atl_paths(target: &str, path: &Path) -> Option<(PathBuf, PathBuf)> {
         let atl_path = path.join("atlfmc");
-        let sub = otry!(lib_subdir(target));
+        let sub = lib_subdir(target)?;
         if atl_path.exists() {
             Some((atl_path.join("lib").join(sub), atl_path.join("include")))
         } else {
@@ -394,15 +384,15 @@ mod impl_ {
     // For MSVC 14 we need to find the Universal CRT as well as either
     // the Windows 10 SDK or Windows 8.1 SDK.
     pub fn find_msvc_14(tool: &str, target: &str) -> Option<Tool> {
-        let vcdir = otry!(get_vc_dir("14.0"));
-        let mut tool = otry!(get_tool(tool, &vcdir, target));
-        otry!(add_sdks(&mut tool, target));
+        let vcdir = get_vc_dir("14.0")?;
+        let mut tool = get_tool(tool, &vcdir, target)?;
+        add_sdks(&mut tool, target)?;
         Some(tool.into_tool())
     }
 
     fn add_sdks(tool: &mut MsvcTool, target: &str) -> Option<()> {
-        let sub = otry!(lib_subdir(target));
-        let (ucrt, ucrt_version) = otry!(get_ucrt_dir());
+        let sub = lib_subdir(target)?;
+        let (ucrt, ucrt_version) = get_ucrt_dir()?;
 
         tool.path
             .push(ucrt.join("bin").join(&ucrt_version).join(sub));
@@ -437,10 +427,10 @@ mod impl_ {
 
     // For MSVC 12 we need to find the Windows 8.1 SDK.
     pub fn find_msvc_12(tool: &str, target: &str) -> Option<Tool> {
-        let vcdir = otry!(get_vc_dir("12.0"));
-        let mut tool = otry!(get_tool(tool, &vcdir, target));
-        let sub = otry!(lib_subdir(target));
-        let sdk81 = otry!(get_sdk81_dir());
+        let vcdir = get_vc_dir("12.0")?;
+        let mut tool = get_tool(tool, &vcdir, target)?;
+        let sub = lib_subdir(target)?;
+        let sdk81 = get_sdk81_dir()?;
         tool.path.push(sdk81.join("bin").join(sub));
         let sdk_lib = sdk81.join("lib").join("winv6.3");
         tool.libs.push(sdk_lib.join("um").join(sub));
@@ -453,10 +443,10 @@ mod impl_ {
 
     // For MSVC 11 we need to find the Windows 8 SDK.
     pub fn find_msvc_11(tool: &str, target: &str) -> Option<Tool> {
-        let vcdir = otry!(get_vc_dir("11.0"));
-        let mut tool = otry!(get_tool(tool, &vcdir, target));
-        let sub = otry!(lib_subdir(target));
-        let sdk8 = otry!(get_sdk8_dir());
+        let vcdir = get_vc_dir("11.0")?;
+        let mut tool = get_tool(tool, &vcdir, target)?;
+        let sub = lib_subdir(target)?;
+        let sdk8 = get_sdk8_dir()?;
         tool.path.push(sdk8.join("bin").join(sub));
         let sdk_lib = sdk8.join("lib").join("win8");
         tool.libs.push(sdk_lib.join("um").join(sub));
@@ -493,7 +483,7 @@ mod impl_ {
                 tool
             })
             .filter_map(|mut tool| {
-                let sub = otry!(vc_lib_subdir(target));
+                let sub = vc_lib_subdir(target)?;
                 tool.libs.push(path.join("lib").join(sub));
                 tool.include.push(path.join("include"));
                 let atlmfc_path = path.join("atlmfc");
@@ -510,8 +500,8 @@ mod impl_ {
     // trying to find.
     fn get_vc_dir(ver: &str) -> Option<PathBuf> {
         let key = r"SOFTWARE\Microsoft\VisualStudio\SxS\VC7";
-        let key = otry!(LOCAL_MACHINE.open(key.as_ref()).ok());
-        let path = otry!(key.query_str(ver).ok());
+        let key = LOCAL_MACHINE.open(key.as_ref()).ok()?;
+        let path = key.query_str(ver).ok()?;
         Some(path.into())
     }
 
@@ -523,19 +513,20 @@ mod impl_ {
     // Returns a pair of (root, version) for the ucrt dir if found
     fn get_ucrt_dir() -> Option<(PathBuf, String)> {
         let key = r"SOFTWARE\Microsoft\Windows Kits\Installed Roots";
-        let key = otry!(LOCAL_MACHINE.open(key.as_ref()).ok());
-        let root = otry!(key.query_str("KitsRoot10").ok());
-        let readdir = otry!(Path::new(&root).join("lib").read_dir().ok());
-        let max_libdir = otry!(readdir
+        let key = LOCAL_MACHINE.open(key.as_ref()).ok()?;
+        let root = key.query_str("KitsRoot10").ok()?;
+        let readdir = Path::new(&root).join("lib").read_dir().ok()?;
+        let max_libdir = readdir
             .filter_map(|dir| dir.ok())
             .map(|dir| dir.path())
-            .filter(|dir| dir
-                .components()
-                .last()
-                .and_then(|c| c.as_os_str().to_str())
-                .map(|c| c.starts_with("10.") && dir.join("ucrt").is_dir())
-                .unwrap_or(false))
-            .max());
+            .filter(|dir| {
+                dir.components()
+                    .last()
+                    .and_then(|c| c.as_os_str().to_str())
+                    .map(|c| c.starts_with("10.") && dir.join("ucrt").is_dir())
+                    .unwrap_or(false)
+            })
+            .max()?;
         let version = max_libdir.components().last().unwrap();
         let version = version.as_os_str().to_str().unwrap().to_string();
         Some((root.into(), version))
@@ -551,19 +542,19 @@ mod impl_ {
     // asciibetically to find the newest one as that is what vcvars does.
     fn get_sdk10_dir() -> Option<(PathBuf, String)> {
         let key = r"SOFTWARE\Microsoft\Microsoft SDKs\Windows\v10.0";
-        let key = otry!(LOCAL_MACHINE.open(key.as_ref()).ok());
-        let root = otry!(key.query_str("InstallationFolder").ok());
-        let readdir = otry!(Path::new(&root).join("lib").read_dir().ok());
+        let key = LOCAL_MACHINE.open(key.as_ref()).ok()?;
+        let root = key.query_str("InstallationFolder").ok()?;
+        let readdir = Path::new(&root).join("lib").read_dir().ok()?;
         let mut dirs = readdir
             .filter_map(|dir| dir.ok())
             .map(|dir| dir.path())
             .collect::<Vec<_>>();
         dirs.sort();
-        let dir = otry!(dirs
+        let dir = dirs
             .into_iter()
             .rev()
             .filter(|dir| dir.join("um").join("x64").join("kernel32.lib").is_file())
-            .next());
+            .next()?;
         let version = dir.components().last().unwrap();
         let version = version.as_os_str().to_str().unwrap().to_string();
         Some((root.into(), version))
@@ -575,15 +566,15 @@ mod impl_ {
     // instead of user mode applications, we would care.
     fn get_sdk81_dir() -> Option<PathBuf> {
         let key = r"SOFTWARE\Microsoft\Microsoft SDKs\Windows\v8.1";
-        let key = otry!(LOCAL_MACHINE.open(key.as_ref()).ok());
-        let root = otry!(key.query_str("InstallationFolder").ok());
+        let key = LOCAL_MACHINE.open(key.as_ref()).ok()?;
+        let root = key.query_str("InstallationFolder").ok()?;
         Some(root.into())
     }
 
     fn get_sdk8_dir() -> Option<PathBuf> {
         let key = r"SOFTWARE\Microsoft\Microsoft SDKs\Windows\v8.0";
-        let key = otry!(LOCAL_MACHINE.open(key.as_ref()).ok());
-        let root = otry!(key.query_str("InstallationFolder").ok());
+        let key = LOCAL_MACHINE.open(key.as_ref()).ok()?;
+        let root = key.query_str("InstallationFolder").ok()?;
         Some(root.into())
     }