Remove -Z flag for suppressing validation mismatch ICE

[rust.git] / src / librustc / session / config.rs

//! Contains infrastructure for configuring the compiler, including parsing
//! command-line options.

// ignore-tidy-filelength

use crate::lint;
use crate::middle::cstore;
use crate::session::{early_error, early_warn, Session};
use crate::session::search_paths::SearchPath;
use crate::hir::map as hir_map;

use rustc_data_structures::fx::FxHashSet;

use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
use rustc_target::spec::{Target, TargetTriple};

use syntax;
use syntax::ast::{self, IntTy, UintTy};
use syntax::source_map::{FileName, FilePathMapping};
use syntax::edition::{Edition, EDITION_NAME_LIST, DEFAULT_EDITION};
use syntax::symbol::{sym, Symbol};
use syntax::feature_gate::UnstableFeatures;

use errors::emitter::HumanReadableErrorType;
use errors::{ColorConfig, FatalError, Handler};

use getopts;

use std::collections::{BTreeMap, BTreeSet};
use std::collections::btree_map::{
    Iter as BTreeMapIter, Keys as BTreeMapKeysIter, Values as BTreeMapValuesIter,
};
use std::fmt;
use std::str::{self, FromStr};
use std::hash::Hasher;
use std::collections::hash_map::DefaultHasher;
use std::iter::FromIterator;
use std::path::{Path, PathBuf};

pub struct Config {
    pub target: Target,
    pub isize_ty: IntTy,
    pub usize_ty: UintTy,
}

#[derive(Clone, Hash, Debug)]
pub enum Sanitizer {
    Address,
    Leak,
    Memory,
    Thread,
}

#[derive(Clone, Copy, Debug, PartialEq, Hash)]
pub enum OptLevel {
    No,         // -O0
    Less,       // -O1
    Default,    // -O2
    Aggressive, // -O3
    Size,       // -Os
    SizeMin,    // -Oz
}

impl_stable_hash_via_hash!(OptLevel);

/// This is what the `LtoCli` values get mapped to after resolving defaults and
/// and taking other command line options into account.
#[derive(Clone, PartialEq)]
pub enum Lto {
    /// Don't do any LTO whatsoever
    No,

    /// Do a full crate graph LTO with ThinLTO
    Thin,

    /// Do a local graph LTO with ThinLTO (only relevant for multiple codegen
    /// units).
    ThinLocal,

    /// Do a full crate graph LTO with "fat" LTO
    Fat,
}

/// The different settings that the `-C lto` flag can have.
#[derive(Clone, Copy, PartialEq, Hash, Debug)]
pub enum LtoCli {
    /// `-C lto=no`
    No,
    /// `-C lto=yes`
    Yes,
    /// `-C lto`
    NoParam,
    /// `-C lto=thin`
    Thin,
    /// `-C lto=fat`
    Fat,
    /// No `-C lto` flag passed
    Unspecified,
}

#[derive(Clone, PartialEq, Hash)]
pub enum LinkerPluginLto {
    LinkerPlugin(PathBuf),
    LinkerPluginAuto,
    Disabled
}

impl LinkerPluginLto {
    pub fn enabled(&self) -> bool {
        match *self {
            LinkerPluginLto::LinkerPlugin(_) |
            LinkerPluginLto::LinkerPluginAuto => true,
            LinkerPluginLto::Disabled => false,
        }
    }
}

#[derive(Clone, PartialEq, Hash)]
pub enum SwitchWithOptPath {
    Enabled(Option<PathBuf>),
    Disabled,
}

impl SwitchWithOptPath {
    pub fn enabled(&self) -> bool {
        match *self {
            SwitchWithOptPath::Enabled(_) => true,
            SwitchWithOptPath::Disabled => false,
        }
    }
}

#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
pub enum SymbolManglingVersion {
    Legacy,
    V0,
}

impl_stable_hash_via_hash!(SymbolManglingVersion);

#[derive(Clone, Copy, PartialEq, Hash)]
pub enum DebugInfo {
    None,
    Limited,
    Full,
}

#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
pub enum OutputType {
    Bitcode,
    Assembly,
    LlvmAssembly,
    Mir,
    Metadata,
    Object,
    Exe,
    DepInfo,
}

impl_stable_hash_via_hash!(OutputType);

impl OutputType {
    fn is_compatible_with_codegen_units_and_single_output_file(&self) -> bool {
        match *self {
            OutputType::Exe | OutputType::DepInfo | OutputType::Metadata => true,
            OutputType::Bitcode
            | OutputType::Assembly
            | OutputType::LlvmAssembly
            | OutputType::Mir
            | OutputType::Object => false,
        }
    }

    fn shorthand(&self) -> &'static str {
        match *self {
            OutputType::Bitcode => "llvm-bc",
            OutputType::Assembly => "asm",
            OutputType::LlvmAssembly => "llvm-ir",
            OutputType::Mir => "mir",
            OutputType::Object => "obj",
            OutputType::Metadata => "metadata",
            OutputType::Exe => "link",
            OutputType::DepInfo => "dep-info",
        }
    }

    fn from_shorthand(shorthand: &str) -> Option<Self> {
        Some(match shorthand {
            "asm" => OutputType::Assembly,
            "llvm-ir" => OutputType::LlvmAssembly,
            "mir" => OutputType::Mir,
            "llvm-bc" => OutputType::Bitcode,
            "obj" => OutputType::Object,
            "metadata" => OutputType::Metadata,
            "link" => OutputType::Exe,
            "dep-info" => OutputType::DepInfo,
            _ => return None,
        })
    }

    fn shorthands_display() -> String {
        format!(
            "`{}`, `{}`, `{}`, `{}`, `{}`, `{}`, `{}`, `{}`",
            OutputType::Bitcode.shorthand(),
            OutputType::Assembly.shorthand(),
            OutputType::LlvmAssembly.shorthand(),
            OutputType::Mir.shorthand(),
            OutputType::Object.shorthand(),
            OutputType::Metadata.shorthand(),
            OutputType::Exe.shorthand(),
            OutputType::DepInfo.shorthand(),
        )
    }

    pub fn extension(&self) -> &'static str {
        match *self {
            OutputType::Bitcode => "bc",
            OutputType::Assembly => "s",
            OutputType::LlvmAssembly => "ll",
            OutputType::Mir => "mir",
            OutputType::Object => "o",
            OutputType::Metadata => "rmeta",
            OutputType::DepInfo => "d",
            OutputType::Exe => "",
        }
    }
}

/// The type of diagnostics output to generate.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum ErrorOutputType {
    /// Output meant for the consumption of humans.
    HumanReadable(HumanReadableErrorType),
    /// Output that's consumed by other tools such as `rustfix` or the `RLS`.
    Json {
        /// Render the JSON in a human readable way (with indents and newlines).
        pretty: bool,
        /// The JSON output includes a `rendered` field that includes the rendered
        /// human output.
        json_rendered: HumanReadableErrorType,
    },
}

impl Default for ErrorOutputType {
    fn default() -> Self {
        Self::HumanReadable(HumanReadableErrorType::Default(ColorConfig::Auto))
    }
}

/// Use tree-based collections to cheaply get a deterministic `Hash` implementation.
/// *Do not* switch `BTreeMap` out for an unsorted container type! That would break
/// dependency tracking for command-line arguments.
#[derive(Clone, Hash)]
pub struct OutputTypes(BTreeMap<OutputType, Option<PathBuf>>);

impl_stable_hash_via_hash!(OutputTypes);

impl OutputTypes {
    pub fn new(entries: &[(OutputType, Option<PathBuf>)]) -> OutputTypes {
        OutputTypes(BTreeMap::from_iter(
            entries.iter().map(|&(k, ref v)| (k, v.clone())),
        ))
    }

    pub fn get(&self, key: &OutputType) -> Option<&Option<PathBuf>> {
        self.0.get(key)
    }

    pub fn contains_key(&self, key: &OutputType) -> bool {
        self.0.contains_key(key)
    }

    pub fn keys(&self) -> BTreeMapKeysIter<'_, OutputType, Option<PathBuf>> {
        self.0.keys()
    }

    pub fn values(&self) -> BTreeMapValuesIter<'_, OutputType, Option<PathBuf>> {
        self.0.values()
    }

    pub fn len(&self) -> usize {
        self.0.len()
    }

    // Returns `true` if any of the output types require codegen or linking.
    pub fn should_codegen(&self) -> bool {
        self.0.keys().any(|k| match *k {
            OutputType::Bitcode
            | OutputType::Assembly
            | OutputType::LlvmAssembly
            | OutputType::Mir
            | OutputType::Object
            | OutputType::Exe => true,
            OutputType::Metadata | OutputType::DepInfo => false,
        })
    }
}

/// Use tree-based collections to cheaply get a deterministic `Hash` implementation.
/// *Do not* switch `BTreeMap` or `BTreeSet` out for an unsorted container type! That
/// would break dependency tracking for command-line arguments.
#[derive(Clone)]
pub struct Externs(BTreeMap<String, ExternEntry>);

#[derive(Clone, Debug, Default)]
pub struct ExternEntry {
    pub locations: BTreeSet<Option<String>>,
    pub is_private_dep: bool
}

impl Externs {
    pub fn new(data: BTreeMap<String, ExternEntry>) -> Externs {
        Externs(data)
    }

    pub fn get(&self, key: &str) -> Option<&ExternEntry> {
        self.0.get(key)
    }

    pub fn iter(&self) -> BTreeMapIter<'_, String, ExternEntry> {
        self.0.iter()
    }
}


macro_rules! hash_option {
    ($opt_name:ident, $opt_expr:expr, $sub_hashes:expr, [UNTRACKED]) => ({});
    ($opt_name:ident, $opt_expr:expr, $sub_hashes:expr, [TRACKED]) => ({
        if $sub_hashes.insert(stringify!($opt_name),
                              $opt_expr as &dyn dep_tracking::DepTrackingHash).is_some() {
            bug!("duplicate key in CLI DepTrackingHash: {}", stringify!($opt_name))
        }
    });
}

macro_rules! top_level_options {
    (pub struct Options { $(
        $opt:ident : $t:ty [$dep_tracking_marker:ident $($warn_val:expr, $warn_text:expr)*],
    )* } ) => (
        #[derive(Clone)]
        pub struct Options {
            $(pub $opt: $t),*
        }

        impl Options {
            pub fn dep_tracking_hash(&self) -> u64 {
                let mut sub_hashes = BTreeMap::new();
                $({
                    hash_option!($opt,
                                 &self.$opt,
                                 &mut sub_hashes,
                                 [$dep_tracking_marker $($warn_val,
                                                         $warn_text,
                                                         self.error_format)*]);
                })*
                let mut hasher = DefaultHasher::new();
                dep_tracking::stable_hash(sub_hashes,
                                          &mut hasher,
                                          self.error_format);
                hasher.finish()
            }
        }
    );
}

// The top-level command-line options struct.
//
// For each option, one has to specify how it behaves with regard to the
// dependency tracking system of incremental compilation. This is done via the
// square-bracketed directive after the field type. The options are:
//
// [TRACKED]
// A change in the given field will cause the compiler to completely clear the
// incremental compilation cache before proceeding.
//
// [UNTRACKED]
// Incremental compilation is not influenced by this option.
//
// If you add a new option to this struct or one of the sub-structs like
// `CodegenOptions`, think about how it influences incremental compilation. If in
// doubt, specify [TRACKED], which is always "correct" but might lead to
// unnecessary re-compilation.
top_level_options!(
    pub struct Options {
        // The crate config requested for the session, which may be combined
        // with additional crate configurations during the compile process.
        crate_types: Vec<CrateType> [TRACKED],
        optimize: OptLevel [TRACKED],
        // Include the `debug_assertions` flag in dependency tracking, since it
        // can influence whether overflow checks are done or not.
        debug_assertions: bool [TRACKED],
        debuginfo: DebugInfo [TRACKED],
        lint_opts: Vec<(String, lint::Level)> [TRACKED],
        lint_cap: Option<lint::Level> [TRACKED],
        describe_lints: bool [UNTRACKED],
        output_types: OutputTypes [TRACKED],
        search_paths: Vec<SearchPath> [UNTRACKED],
        libs: Vec<(String, Option<String>, Option<cstore::NativeLibraryKind>)> [TRACKED],
        maybe_sysroot: Option<PathBuf> [UNTRACKED],

        target_triple: TargetTriple [TRACKED],

        test: bool [TRACKED],
        error_format: ErrorOutputType [UNTRACKED],

        // If `Some`, enable incremental compilation, using the given
        // directory to store intermediate results.
        incremental: Option<PathBuf> [UNTRACKED],

        debugging_opts: DebuggingOptions [TRACKED],
        prints: Vec<PrintRequest> [UNTRACKED],
        // Determines which borrow checker(s) to run. This is the parsed, sanitized
        // version of `debugging_opts.borrowck`, which is just a plain string.
        borrowck_mode: BorrowckMode [UNTRACKED],
        cg: CodegenOptions [TRACKED],
        externs: Externs [UNTRACKED],
        crate_name: Option<String> [TRACKED],
        // An optional name to use as the crate for std during std injection,
        // written `extern crate name as std`. Defaults to `std`. Used by
        // out-of-tree drivers.
        alt_std_name: Option<String> [TRACKED],
        // Indicates how the compiler should treat unstable features.
        unstable_features: UnstableFeatures [TRACKED],

        // Indicates whether this run of the compiler is actually rustdoc. This
        // is currently just a hack and will be removed eventually, so please
        // try to not rely on this too much.
        actually_rustdoc: bool [TRACKED],

        // Specifications of codegen units / ThinLTO which are forced as a
        // result of parsing command line options. These are not necessarily
        // what rustc was invoked with, but massaged a bit to agree with
        // commands like `--emit llvm-ir` which they're often incompatible with
        // if we otherwise use the defaults of rustc.
        cli_forced_codegen_units: Option<usize> [UNTRACKED],
        cli_forced_thinlto_off: bool [UNTRACKED],

        // Remap source path prefixes in all output (messages, object files, debug, etc.).
        remap_path_prefix: Vec<(PathBuf, PathBuf)> [UNTRACKED],

        edition: Edition [TRACKED],

        // `true` if we're emitting JSON blobs about each artifact produced
        // by the compiler.
        json_artifact_notifications: bool [TRACKED],

        pretty: Option<(PpMode, Option<UserIdentifiedItem>)> [UNTRACKED],
    }
);

#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum PrintRequest {
    FileNames,
    Sysroot,
    CrateName,
    Cfg,
    TargetList,
    TargetCPUs,
    TargetFeatures,
    RelocationModels,
    CodeModels,
    TlsModels,
    TargetSpec,
    NativeStaticLibs,
}

#[derive(Copy, Clone)]
pub enum BorrowckMode {
    Mir,
    Migrate,
}

impl BorrowckMode {
    /// Returns whether we should run the MIR-based borrow check, but also fall back
    /// on the AST borrow check if the MIR-based one errors.
    pub fn migrate(self) -> bool {
        match self {
            BorrowckMode::Mir => false,
            BorrowckMode::Migrate => true,
        }
    }
}

pub enum Input {
    /// Load source code from a file.
    File(PathBuf),
    /// Load source code from a string.
    Str {
        /// A string that is shown in place of a filename.
        name: FileName,
        /// An anonymous string containing the source code.
        input: String,
    },
}

impl Input {
    pub fn filestem(&self) -> &str {
        match *self {
            Input::File(ref ifile) => ifile.file_stem().unwrap().to_str().unwrap(),
            Input::Str { .. } => "rust_out",
        }
    }

    pub fn get_input(&mut self) -> Option<&mut String> {
        match *self {
            Input::File(_) => None,
            Input::Str { ref mut input, .. } => Some(input),
        }
    }

    pub fn source_name(&self) -> FileName {
        match *self {
            Input::File(ref ifile) => ifile.clone().into(),
            Input::Str { ref name, .. } => name.clone(),
        }
    }
}

#[derive(Clone, Hash)]
pub struct OutputFilenames {
    pub out_directory: PathBuf,
    pub out_filestem: String,
    pub single_output_file: Option<PathBuf>,
    pub extra: String,
    pub outputs: OutputTypes,
}

impl_stable_hash_via_hash!(OutputFilenames);

pub const RUST_CGU_EXT: &str = "rcgu";

impl OutputFilenames {
    pub fn path(&self, flavor: OutputType) -> PathBuf {
        self.outputs
            .get(&flavor)
            .and_then(|p| p.to_owned())
            .or_else(|| self.single_output_file.clone())
            .unwrap_or_else(|| self.temp_path(flavor, None))
    }

    /// Gets the path where a compilation artifact of the given type for the
    /// given codegen unit should be placed on disk. If codegen_unit_name is
    /// None, a path distinct from those of any codegen unit will be generated.
    pub fn temp_path(&self, flavor: OutputType, codegen_unit_name: Option<&str>) -> PathBuf {
        let extension = flavor.extension();
        self.temp_path_ext(extension, codegen_unit_name)
    }

    /// Like temp_path, but also supports things where there is no corresponding
    /// OutputType, like noopt-bitcode or lto-bitcode.
    pub fn temp_path_ext(&self, ext: &str, codegen_unit_name: Option<&str>) -> PathBuf {
        let base = self.out_directory.join(&self.filestem());

        let mut extension = String::new();

        if let Some(codegen_unit_name) = codegen_unit_name {
            extension.push_str(codegen_unit_name);
        }

        if !ext.is_empty() {
            if !extension.is_empty() {
                extension.push_str(".");
                extension.push_str(RUST_CGU_EXT);
                extension.push_str(".");
            }

            extension.push_str(ext);
        }

        let path = base.with_extension(&extension[..]);
        path
    }

    pub fn with_extension(&self, extension: &str) -> PathBuf {
        self.out_directory
            .join(&self.filestem())
            .with_extension(extension)
    }

    pub fn filestem(&self) -> String {
        format!("{}{}", self.out_filestem, self.extra)
    }
}

pub fn host_triple() -> &'static str {
    // Get the host triple out of the build environment. This ensures that our
    // idea of the host triple is the same as for the set of libraries we've
    // actually built.  We can't just take LLVM's host triple because they
    // normalize all ix86 architectures to i386.
    //
    // Instead of grabbing the host triple (for the current host), we grab (at
    // compile time) the target triple that this rustc is built with and
    // calling that (at runtime) the host triple.
    (option_env!("CFG_COMPILER_HOST_TRIPLE")).expect("CFG_COMPILER_HOST_TRIPLE")
}

impl Default for Options {
    fn default() -> Options {
        Options {
            crate_types: Vec::new(),
            optimize: OptLevel::No,
            debuginfo: DebugInfo::None,
            lint_opts: Vec::new(),
            lint_cap: None,
            describe_lints: false,
            output_types: OutputTypes(BTreeMap::new()),
            search_paths: vec![],
            maybe_sysroot: None,
            target_triple: TargetTriple::from_triple(host_triple()),
            test: false,
            incremental: None,
            debugging_opts: basic_debugging_options(),
            prints: Vec::new(),
            borrowck_mode: BorrowckMode::Migrate,
            cg: basic_codegen_options(),
            error_format: ErrorOutputType::default(),
            externs: Externs(BTreeMap::new()),
            crate_name: None,
            alt_std_name: None,
            libs: Vec::new(),
            unstable_features: UnstableFeatures::Disallow,
            debug_assertions: true,
            actually_rustdoc: false,
            cli_forced_codegen_units: None,
            cli_forced_thinlto_off: false,
            remap_path_prefix: Vec::new(),
            edition: DEFAULT_EDITION,
            json_artifact_notifications: false,
            pretty: None,
        }
    }
}

impl Options {
    /// Returns `true` if there is a reason to build the dep graph.
    pub fn build_dep_graph(&self) -> bool {
        self.incremental.is_some() || self.debugging_opts.dump_dep_graph
            || self.debugging_opts.query_dep_graph
    }

    #[inline(always)]
    pub fn enable_dep_node_debug_strs(&self) -> bool {
        cfg!(debug_assertions)
            && (self.debugging_opts.query_dep_graph || self.debugging_opts.incremental_info)
    }

    pub fn file_path_mapping(&self) -> FilePathMapping {
        FilePathMapping::new(self.remap_path_prefix.clone())
    }

    /// Returns `true` if there will be an output file generated.
    pub fn will_create_output_file(&self) -> bool {
        !self.debugging_opts.parse_only && // The file is just being parsed
            !self.debugging_opts.ls // The file is just being queried
    }

    #[inline]
    pub fn share_generics(&self) -> bool {
        match self.debugging_opts.share_generics {
            Some(setting) => setting,
            None => {
                match self.optimize {
                    OptLevel::No   |
                    OptLevel::Less |
                    OptLevel::Size |
                    OptLevel::SizeMin => true,
                    OptLevel::Default    |
                    OptLevel::Aggressive => false,
                }
            }
        }
    }
}

// The type of entry function, so users can have their own entry functions
#[derive(Copy, Clone, PartialEq, Hash, Debug)]
pub enum EntryFnType {
    Main,
    Start,
}

impl_stable_hash_via_hash!(EntryFnType);

#[derive(Copy, PartialEq, PartialOrd, Clone, Ord, Eq, Hash, Debug, HashStable)]
pub enum CrateType {
    Executable,
    Dylib,
    Rlib,
    Staticlib,
    Cdylib,
    ProcMacro,
}

#[derive(Clone, Hash)]
pub enum Passes {
    Some(Vec<String>),
    All,
}

impl Passes {
    pub fn is_empty(&self) -> bool {
        match *self {
            Passes::Some(ref v) => v.is_empty(),
            Passes::All => false,
        }
    }
}

/// Defines all `CodegenOptions`/`DebuggingOptions` fields and parsers all at once. The goal of this
/// macro is to define an interface that can be programmatically used by the option parser
/// to initialize the struct without hardcoding field names all over the place.
///
/// The goal is to invoke this macro once with the correct fields, and then this macro generates all
/// necessary code. The main gotcha of this macro is the `cgsetters` module which is a bunch of
/// generated code to parse an option into its respective field in the struct. There are a few
/// hand-written parsers for parsing specific types of values in this module.
macro_rules! options {
    ($struct_name:ident, $setter_name:ident, $defaultfn:ident,
     $buildfn:ident, $prefix:expr, $outputname:expr,
     $stat:ident, $mod_desc:ident, $mod_set:ident,
     $($opt:ident : $t:ty = (
        $init:expr,
        $parse:ident,
        [$dep_tracking_marker:ident $(($dep_warn_val:expr, $dep_warn_text:expr))*],
        $desc:expr)
     ),* ,) =>
(
    #[derive(Clone)]
    pub struct $struct_name { $(pub $opt: $t),* }

    pub fn $defaultfn() -> $struct_name {
        $struct_name { $($opt: $init),* }
    }

    pub fn $buildfn(matches: &getopts::Matches, error_format: ErrorOutputType) -> $struct_name
    {
        let mut op = $defaultfn();
        for option in matches.opt_strs($prefix) {
            let mut iter = option.splitn(2, '=');
            let key = iter.next().unwrap();
            let value = iter.next();
            let option_to_lookup = key.replace("-", "_");
            let mut found = false;
            for &(candidate, setter, opt_type_desc, _) in $stat {
                if option_to_lookup != candidate { continue }
                if !setter(&mut op, value) {
                    match (value, opt_type_desc) {
                        (Some(..), None) => {
                            early_error(error_format, &format!("{} option `{}` takes no \
                                                                value", $outputname, key))
                        }
                        (None, Some(type_desc)) => {
                            early_error(error_format, &format!("{0} option `{1}` requires \
                                                                {2} ({3} {1}=<value>)",
                                                               $outputname, key,
                                                               type_desc, $prefix))
                        }
                        (Some(value), Some(type_desc)) => {
                            early_error(error_format, &format!("incorrect value `{}` for {} \
                                                                option `{}` - {} was expected",
                                                               value, $outputname,
                                                               key, type_desc))
                        }
                        (None, None) => bug!()
                    }
                }
                found = true;
                break;
            }
            if !found {
                early_error(error_format, &format!("unknown {} option: `{}`",
                                                   $outputname, key));
            }
        }
        return op;
    }

    impl dep_tracking::DepTrackingHash for $struct_name {
        fn hash(&self, hasher: &mut DefaultHasher, error_format: ErrorOutputType) {
            let mut sub_hashes = BTreeMap::new();
            $({
                hash_option!($opt,
                             &self.$opt,
                             &mut sub_hashes,
                             [$dep_tracking_marker $($dep_warn_val,
                                                     $dep_warn_text,
                                                     error_format)*]);
            })*
            dep_tracking::stable_hash(sub_hashes, hasher, error_format);
        }
    }

    pub type $setter_name = fn(&mut $struct_name, v: Option<&str>) -> bool;
    pub const $stat: &[(&str, $setter_name, Option<&str>, &str)] =
        &[ $( (stringify!($opt), $mod_set::$opt, $mod_desc::$parse, $desc) ),* ];

    #[allow(non_upper_case_globals, dead_code)]
    mod $mod_desc {
        pub const parse_bool: Option<&str> = None;
        pub const parse_opt_bool: Option<&str> =
            Some("one of: `y`, `yes`, `on`, `n`, `no`, or `off`");
        pub const parse_string: Option<&str> = Some("a string");
        pub const parse_string_push: Option<&str> = Some("a string");
        pub const parse_pathbuf_push: Option<&str> = Some("a path");
        pub const parse_opt_string: Option<&str> = Some("a string");
        pub const parse_opt_pathbuf: Option<&str> = Some("a path");
        pub const parse_list: Option<&str> = Some("a space-separated list of strings");
        pub const parse_opt_list: Option<&str> = Some("a space-separated list of strings");
        pub const parse_opt_comma_list: Option<&str> = Some("a comma-separated list of strings");
        pub const parse_threads: Option<&str> = Some("a number");
        pub const parse_uint: Option<&str> = Some("a number");
        pub const parse_passes: Option<&str> =
            Some("a space-separated list of passes, or `all`");
        pub const parse_opt_uint: Option<&str> =
            Some("a number");
        pub const parse_panic_strategy: Option<&str> =
            Some("either `unwind` or `abort`");
        pub const parse_relro_level: Option<&str> =
            Some("one of: `full`, `partial`, or `off`");
        pub const parse_sanitizer: Option<&str> =
            Some("one of: `address`, `leak`, `memory` or `thread`");
        pub const parse_linker_flavor: Option<&str> =
            Some(::rustc_target::spec::LinkerFlavor::one_of());
        pub const parse_optimization_fuel: Option<&str> =
            Some("crate=integer");
        pub const parse_unpretty: Option<&str> =
            Some("`string` or `string=string`");
        pub const parse_treat_err_as_bug: Option<&str> =
            Some("either no value or a number bigger than 0");
        pub const parse_lto: Option<&str> =
            Some("either a boolean (`yes`, `no`, `on`, `off`, etc), `thin`, \
                  `fat`, or omitted");
        pub const parse_linker_plugin_lto: Option<&str> =
            Some("either a boolean (`yes`, `no`, `on`, `off`, etc), \
                  or the path to the linker plugin");
        pub const parse_switch_with_opt_path: Option<&str> =
            Some("an optional path to the profiling data output directory");
        pub const parse_merge_functions: Option<&str> =
            Some("one of: `disabled`, `trampolines`, or `aliases`");
        pub const parse_symbol_mangling_version: Option<&str> =
            Some("either `legacy` or `v0` (RFC 2603)");
    }

    #[allow(dead_code)]
    mod $mod_set {
        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath,
            SymbolManglingVersion};
        use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
        use std::path::PathBuf;
        use std::str::FromStr;

        $(
            pub fn $opt(cg: &mut $struct_name, v: Option<&str>) -> bool {
                $parse(&mut cg.$opt, v)
            }
        )*

        fn parse_bool(slot: &mut bool, v: Option<&str>) -> bool {
            match v {
                Some(..) => false,
                None => { *slot = true; true }
            }
        }

        fn parse_opt_bool(slot: &mut Option<bool>, v: Option<&str>) -> bool {
            match v {
                Some(s) => {
                    match s {
                        "n" | "no" | "off" => {
                            *slot = Some(false);
                        }
                        "y" | "yes" | "on" => {
                            *slot = Some(true);
                        }
                        _ => { return false; }
                    }

                    true
                },
                None => { *slot = Some(true); true }
            }
        }

        fn parse_opt_string(slot: &mut Option<String>, v: Option<&str>) -> bool {
            match v {
                Some(s) => { *slot = Some(s.to_string()); true },
                None => false,
            }
        }

        fn parse_opt_pathbuf(slot: &mut Option<PathBuf>, v: Option<&str>) -> bool {
            match v {
                Some(s) => { *slot = Some(PathBuf::from(s)); true },
                None => false,
            }
        }

        fn parse_string(slot: &mut String, v: Option<&str>) -> bool {
            match v {
                Some(s) => { *slot = s.to_string(); true },
                None => false,
            }
        }

        fn parse_string_push(slot: &mut Vec<String>, v: Option<&str>) -> bool {
            match v {
                Some(s) => { slot.push(s.to_string()); true },
                None => false,
            }
        }

        fn parse_pathbuf_push(slot: &mut Vec<PathBuf>, v: Option<&str>) -> bool {
            match v {
                Some(s) => { slot.push(PathBuf::from(s)); true },
                None => false,
            }
        }

        fn parse_list(slot: &mut Vec<String>, v: Option<&str>)
                      -> bool {
            match v {
                Some(s) => {
                    slot.extend(s.split_whitespace().map(|s| s.to_string()));
                    true
                },
                None => false,
            }
        }

        fn parse_opt_list(slot: &mut Option<Vec<String>>, v: Option<&str>)
                      -> bool {
            match v {
                Some(s) => {
                    let v = s.split_whitespace().map(|s| s.to_string()).collect();
                    *slot = Some(v);
                    true
                },
                None => false,
            }
        }

        fn parse_opt_comma_list(slot: &mut Option<Vec<String>>, v: Option<&str>)
                      -> bool {
            match v {
                Some(s) => {
                    let v = s.split(',').map(|s| s.to_string()).collect();
                    *slot = Some(v);
                    true
                },
                None => false,
            }
        }

        fn parse_threads(slot: &mut usize, v: Option<&str>) -> bool {
            match v.and_then(|s| s.parse().ok()) {
                Some(0) => { *slot = ::num_cpus::get(); true },
                Some(i) => { *slot = i; true },
                None => false
            }
        }

        fn parse_uint(slot: &mut usize, v: Option<&str>) -> bool {
            match v.and_then(|s| s.parse().ok()) {
                Some(i) => { *slot = i; true },
                None => false
            }
        }

        fn parse_opt_uint(slot: &mut Option<usize>, v: Option<&str>) -> bool {
            match v {
                Some(s) => { *slot = s.parse().ok(); slot.is_some() }
                None => { *slot = None; false }
            }
        }

        fn parse_passes(slot: &mut Passes, v: Option<&str>) -> bool {
            match v {
                Some("all") => {
                    *slot = Passes::All;
                    true
                }
                v => {
                    let mut passes = vec![];
                    if parse_list(&mut passes, v) {
                        *slot = Passes::Some(passes);
                        true
                    } else {
                        false
                    }
                }
            }
        }

        fn parse_panic_strategy(slot: &mut Option<PanicStrategy>, v: Option<&str>) -> bool {
            match v {
                Some("unwind") => *slot = Some(PanicStrategy::Unwind),
                Some("abort") => *slot = Some(PanicStrategy::Abort),
                _ => return false
            }
            true
        }

        fn parse_relro_level(slot: &mut Option<RelroLevel>, v: Option<&str>) -> bool {
            match v {
                Some(s) => {
                    match s.parse::<RelroLevel>() {
                        Ok(level) => *slot = Some(level),
                        _ => return false
                    }
                },
                _ => return false
            }
            true
        }

        fn parse_sanitizer(slote: &mut Option<Sanitizer>, v: Option<&str>) -> bool {
            match v {
                Some("address") => *slote = Some(Sanitizer::Address),
                Some("leak") => *slote = Some(Sanitizer::Leak),
                Some("memory") => *slote = Some(Sanitizer::Memory),
                Some("thread") => *slote = Some(Sanitizer::Thread),
                _ => return false,
            }
            true
        }

        fn parse_linker_flavor(slote: &mut Option<LinkerFlavor>, v: Option<&str>) -> bool {
            match v.and_then(LinkerFlavor::from_str) {
                Some(lf) => *slote = Some(lf),
                _ => return false,
            }
            true
        }

        fn parse_optimization_fuel(slot: &mut Option<(String, u64)>, v: Option<&str>) -> bool {
            match v {
                None => false,
                Some(s) => {
                    let parts = s.split('=').collect::<Vec<_>>();
                    if parts.len() != 2 { return false; }
                    let crate_name = parts[0].to_string();
                    let fuel = parts[1].parse::<u64>();
                    if fuel.is_err() { return false; }
                    *slot = Some((crate_name, fuel.unwrap()));
                    true
                }
            }
        }

        fn parse_unpretty(slot: &mut Option<String>, v: Option<&str>) -> bool {
            match v {
                None => false,
                Some(s) if s.split('=').count() <= 2 => {
                    *slot = Some(s.to_string());
                    true
                }
                _ => false,
            }
        }

        fn parse_treat_err_as_bug(slot: &mut Option<usize>, v: Option<&str>) -> bool {
            match v {
                Some(s) => { *slot = s.parse().ok().filter(|&x| x != 0); slot.unwrap_or(0) != 0 }
                None => { *slot = Some(1); true }
            }
        }

        fn parse_lto(slot: &mut LtoCli, v: Option<&str>) -> bool {
            if v.is_some() {
                let mut bool_arg = None;
                if parse_opt_bool(&mut bool_arg, v) {
                    *slot = if bool_arg.unwrap() {
                        LtoCli::Yes
                    } else {
                        LtoCli::No
                    };
                    return true
                }
            }

            *slot = match v {
                None => LtoCli::NoParam,
                Some("thin") => LtoCli::Thin,
                Some("fat") => LtoCli::Fat,
                Some(_) => return false,
            };
            true
        }

        fn parse_linker_plugin_lto(slot: &mut LinkerPluginLto, v: Option<&str>) -> bool {
            if v.is_some() {
                let mut bool_arg = None;
                if parse_opt_bool(&mut bool_arg, v) {
                    *slot = if bool_arg.unwrap() {
                        LinkerPluginLto::LinkerPluginAuto
                    } else {
                        LinkerPluginLto::Disabled
                    };
                    return true
                }
            }

            *slot = match v {
                None => LinkerPluginLto::LinkerPluginAuto,
                Some(path) => LinkerPluginLto::LinkerPlugin(PathBuf::from(path)),
            };
            true
        }

        fn parse_switch_with_opt_path(slot: &mut SwitchWithOptPath, v: Option<&str>) -> bool {
            *slot = match v {
                None => SwitchWithOptPath::Enabled(None),
                Some(path) => SwitchWithOptPath::Enabled(Some(PathBuf::from(path))),
            };
            true
        }

        fn parse_merge_functions(slot: &mut Option<MergeFunctions>, v: Option<&str>) -> bool {
            match v.and_then(|s| MergeFunctions::from_str(s).ok()) {
                Some(mergefunc) => *slot = Some(mergefunc),
                _ => return false,
            }
            true
        }

        fn parse_symbol_mangling_version(
            slot: &mut SymbolManglingVersion,
            v: Option<&str>,
        ) -> bool {
            *slot = match v {
                Some("legacy") => SymbolManglingVersion::Legacy,
                Some("v0") => SymbolManglingVersion::V0,
                _ => return false,
            };
            true
        }
    }
) }

options! {CodegenOptions, CodegenSetter, basic_codegen_options,
          build_codegen_options, "C", "codegen",
          CG_OPTIONS, cg_type_desc, cgsetters,
    ar: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "this option is deprecated and does nothing"),
    linker: Option<PathBuf> = (None, parse_opt_pathbuf, [UNTRACKED],
        "system linker to link outputs with"),
    link_arg: Vec<String> = (vec![], parse_string_push, [UNTRACKED],
        "a single extra argument to append to the linker invocation (can be used several times)"),
    link_args: Option<Vec<String>> = (None, parse_opt_list, [UNTRACKED],
        "extra arguments to append to the linker invocation (space separated)"),
    link_dead_code: bool = (false, parse_bool, [UNTRACKED],
        "don't let linker strip dead code (turning it on can be used for code coverage)"),
    lto: LtoCli = (LtoCli::Unspecified, parse_lto, [TRACKED],
        "perform LLVM link-time optimizations"),
    target_cpu: Option<String> = (None, parse_opt_string, [TRACKED],
        "select target processor (`rustc --print target-cpus` for details)"),
    target_feature: String = (String::new(), parse_string, [TRACKED],
        "target specific attributes. (`rustc --print target-features` for details). \
        This feature is unsafe."),
    passes: Vec<String> = (Vec::new(), parse_list, [TRACKED],
        "a list of extra LLVM passes to run (space separated)"),
    llvm_args: Vec<String> = (Vec::new(), parse_list, [TRACKED],
        "a list of arguments to pass to LLVM (space separated)"),
    save_temps: bool = (false, parse_bool, [UNTRACKED],
        "save all temporary output files during compilation"),
    rpath: bool = (false, parse_bool, [UNTRACKED],
        "set rpath values in libs/exes"),
    overflow_checks: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "use overflow checks for integer arithmetic"),
    no_prepopulate_passes: bool = (false, parse_bool, [TRACKED],
        "don't pre-populate the pass manager with a list of passes"),
    no_vectorize_loops: bool = (false, parse_bool, [TRACKED],
        "don't run the loop vectorization optimization passes"),
    no_vectorize_slp: bool = (false, parse_bool, [TRACKED],
        "don't run LLVM's SLP vectorization pass"),
    soft_float: bool = (false, parse_bool, [TRACKED],
        "use soft float ABI (*eabihf targets only)"),
    prefer_dynamic: bool = (false, parse_bool, [TRACKED],
        "prefer dynamic linking to static linking"),
    no_integrated_as: bool = (false, parse_bool, [TRACKED],
        "use an external assembler rather than LLVM's integrated one"),
    no_redzone: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "disable the use of the redzone"),
    relocation_model: Option<String> = (None, parse_opt_string, [TRACKED],
        "choose the relocation model to use (`rustc --print relocation-models` for details)"),
    code_model: Option<String> = (None, parse_opt_string, [TRACKED],
        "choose the code model to use (`rustc --print code-models` for details)"),
    metadata: Vec<String> = (Vec::new(), parse_list, [TRACKED],
        "metadata to mangle symbol names with"),
    extra_filename: String = (String::new(), parse_string, [UNTRACKED],
        "extra data to put in each output filename"),
    codegen_units: Option<usize> = (None, parse_opt_uint, [UNTRACKED],
        "divide crate into N units to optimize in parallel"),
    remark: Passes = (Passes::Some(Vec::new()), parse_passes, [UNTRACKED],
        "print remarks for these optimization passes (space separated, or \"all\")"),
    no_stack_check: bool = (false, parse_bool, [UNTRACKED],
        "the `--no-stack-check` flag is deprecated and does nothing"),
    debuginfo: Option<usize> = (None, parse_opt_uint, [TRACKED],
        "debug info emission level, 0 = no debug info, 1 = line tables only, \
         2 = full debug info with variable and type information"),
    opt_level: Option<String> = (None, parse_opt_string, [TRACKED],
        "optimize with possible levels 0-3, s, or z"),
    force_frame_pointers: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "force use of the frame pointers"),
    debug_assertions: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "explicitly enable the cfg(debug_assertions) directive"),
    inline_threshold: Option<usize> = (None, parse_opt_uint, [TRACKED],
        "set the threshold for inlining a function (default: 225)"),
    panic: Option<PanicStrategy> = (None, parse_panic_strategy,
        [TRACKED], "panic strategy to compile crate with"),
    incremental: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "enable incremental compilation"),
    default_linker_libraries: Option<bool> = (None, parse_opt_bool, [UNTRACKED],
        "allow the linker to link its default libraries"),
    linker_flavor: Option<LinkerFlavor> = (None, parse_linker_flavor, [UNTRACKED],
                                           "linker flavor"),
    linker_plugin_lto: LinkerPluginLto = (LinkerPluginLto::Disabled,
        parse_linker_plugin_lto, [TRACKED],
        "generate build artifacts that are compatible with linker-based LTO."),
    profile_generate: SwitchWithOptPath = (SwitchWithOptPath::Disabled,
        parse_switch_with_opt_path, [TRACKED],
        "compile the program with profiling instrumentation"),
    profile_use: Option<PathBuf> = (None, parse_opt_pathbuf, [TRACKED],
        "use the given `.profdata` file for profile-guided optimization"),
}

options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
          build_debugging_options, "Z", "debugging",
          DB_OPTIONS, db_type_desc, dbsetters,
    codegen_backend: Option<String> = (None, parse_opt_string, [TRACKED],
        "the backend to use"),
    verbose: bool = (false, parse_bool, [UNTRACKED],
        "in general, enable more debug printouts"),
    span_free_formats: bool = (false, parse_bool, [UNTRACKED],
        "when debug-printing compiler state, do not include spans"), // o/w tests have closure@path
    identify_regions: bool = (false, parse_bool, [UNTRACKED],
        "make unnamed regions display as '# (where # is some non-ident unique id)"),
    borrowck: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "select which borrowck is used (`mir` or `migrate`)"),
    time_passes: bool = (false, parse_bool, [UNTRACKED],
        "measure time of each rustc pass"),
    time: bool = (false, parse_bool, [UNTRACKED],
        "measure time of rustc processes"),
    time_llvm_passes: bool = (false, parse_bool, [UNTRACKED],
        "measure time of each LLVM pass"),
    input_stats: bool = (false, parse_bool, [UNTRACKED],
        "gather statistics about the input"),
    asm_comments: bool = (false, parse_bool, [TRACKED],
        "generate comments into the assembly (may change behavior)"),
    verify_llvm_ir: bool = (false, parse_bool, [TRACKED],
        "verify LLVM IR"),
    borrowck_stats: bool = (false, parse_bool, [UNTRACKED],
        "gather borrowck statistics"),
    no_landing_pads: bool = (false, parse_bool, [TRACKED],
        "omit landing pads for unwinding"),
    fewer_names: bool = (false, parse_bool, [TRACKED],
        "reduce memory use by retaining fewer names within compilation artifacts (LLVM-IR)"),
    meta_stats: bool = (false, parse_bool, [UNTRACKED],
        "gather metadata statistics"),
    print_link_args: bool = (false, parse_bool, [UNTRACKED],
        "print the arguments passed to the linker"),
    print_llvm_passes: bool = (false, parse_bool, [UNTRACKED],
        "prints the LLVM optimization passes being run"),
    ast_json: bool = (false, parse_bool, [UNTRACKED],
        "print the AST as JSON and halt"),
    // We default to 1 here since we want to behave like
    // a sequential compiler for now. This'll likely be adjusted
    // in the future. Note that -Zthreads=0 is the way to get
    // the num_cpus behavior.
    threads: usize = (1, parse_threads, [UNTRACKED],
        "use a thread pool with N threads"),
    ast_json_noexpand: bool = (false, parse_bool, [UNTRACKED],
        "print the pre-expansion AST as JSON and halt"),
    ls: bool = (false, parse_bool, [UNTRACKED],
        "list the symbols defined by a library crate"),
    save_analysis: bool = (false, parse_bool, [UNTRACKED],
        "write syntax and type analysis (in JSON format) information, in \
         addition to normal output"),
    print_region_graph: bool = (false, parse_bool, [UNTRACKED],
        "prints region inference graph. \
         Use with RUST_REGION_GRAPH=help for more info"),
    parse_only: bool = (false, parse_bool, [UNTRACKED],
        "parse only; do not compile, assemble, or link"),
    dual_proc_macros: bool = (false, parse_bool, [TRACKED],
        "load proc macros for both target and host, but only link to the target"),
    no_codegen: bool = (false, parse_bool, [TRACKED],
        "run all passes except codegen; no output"),
    treat_err_as_bug: Option<usize> = (None, parse_treat_err_as_bug, [TRACKED],
        "treat error number `val` that occurs as bug"),
    report_delayed_bugs: bool = (false, parse_bool, [TRACKED],
        "immediately print bugs registered with `delay_span_bug`"),
    external_macro_backtrace: bool = (false, parse_bool, [UNTRACKED],
        "show macro backtraces even for non-local macros"),
    teach: bool = (false, parse_bool, [TRACKED],
        "show extended diagnostic help"),
    terminal_width: Option<usize> = (None, parse_opt_uint, [UNTRACKED],
        "set the current terminal width"),
    panic_abort_tests: bool = (false, parse_bool, [TRACKED],
        "support compiling tests with panic=abort"),
    continue_parse_after_error: bool = (false, parse_bool, [TRACKED],
        "attempt to recover from parse errors (experimental)"),
    dep_tasks: bool = (false, parse_bool, [UNTRACKED],
        "print tasks that execute and the color their dep node gets (requires debug build)"),
    incremental: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "enable incremental compilation (experimental)"),
    incremental_queries: bool = (true, parse_bool, [UNTRACKED],
        "enable incremental compilation support for queries (experimental)"),
    incremental_info: bool = (false, parse_bool, [UNTRACKED],
        "print high-level information about incremental reuse (or the lack thereof)"),
    incremental_dump_hash: bool = (false, parse_bool, [UNTRACKED],
        "dump hash information in textual format to stdout"),
    incremental_verify_ich: bool = (false, parse_bool, [UNTRACKED],
        "verify incr. comp. hashes of green query instances"),
    incremental_ignore_spans: bool = (false, parse_bool, [UNTRACKED],
        "ignore spans during ICH computation -- used for testing"),
    instrument_mcount: bool = (false, parse_bool, [TRACKED],
        "insert function instrument code for mcount-based tracing"),
    dump_dep_graph: bool = (false, parse_bool, [UNTRACKED],
        "dump the dependency graph to $RUST_DEP_GRAPH (default: /tmp/dep_graph.gv)"),
    query_dep_graph: bool = (false, parse_bool, [UNTRACKED],
        "enable queries of the dependency graph for regression testing"),
    no_analysis: bool = (false, parse_bool, [UNTRACKED],
        "parse and expand the source, but run no analysis"),
    extra_plugins: Vec<String> = (Vec::new(), parse_list, [TRACKED],
        "load extra plugins"),
    unstable_options: bool = (false, parse_bool, [UNTRACKED],
        "adds unstable command line options to rustc interface"),
    force_overflow_checks: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "force overflow checks on or off"),
    trace_macros: bool = (false, parse_bool, [UNTRACKED],
        "for every macro invocation, print its name and arguments"),
    debug_macros: bool = (false, parse_bool, [TRACKED],
        "emit line numbers debug info inside macros"),
    keep_hygiene_data: bool = (false, parse_bool, [UNTRACKED],
        "don't clear the hygiene data after analysis"),
    keep_ast: bool = (false, parse_bool, [UNTRACKED],
        "keep the AST after lowering it to HIR"),
    show_span: Option<String> = (None, parse_opt_string, [TRACKED],
        "show spans for compiler debugging (expr|pat|ty)"),
    print_type_sizes: bool = (false, parse_bool, [UNTRACKED],
        "print layout information for each type encountered"),
    print_mono_items: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "print the result of the monomorphization collection pass"),
    mir_opt_level: usize = (1, parse_uint, [TRACKED],
        "set the MIR optimization level (0-3, default: 1)"),
    mutable_noalias: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "emit noalias metadata for mutable references (default: no)"),
    dump_mir: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "dump MIR state to file.
        `val` is used to select which passes and functions to dump. For example:
        `all` matches all passes and functions,
        `foo` matches all passes for functions whose name contains 'foo',
        `foo & ConstProp` only the 'ConstProp' pass for function names containing 'foo',
        `foo | bar` all passes for function names containing 'foo' or 'bar'."),

    dump_mir_dir: String = (String::from("mir_dump"), parse_string, [UNTRACKED],
        "the directory the MIR is dumped into"),
    dump_mir_graphviz: bool = (false, parse_bool, [UNTRACKED],
        "in addition to `.mir` files, create graphviz `.dot` files"),
    dump_mir_exclude_pass_number: bool = (false, parse_bool, [UNTRACKED],
        "if set, exclude the pass number when dumping MIR (used in tests)"),
    mir_emit_retag: bool = (false, parse_bool, [TRACKED],
        "emit Retagging MIR statements, interpreted e.g., by miri; implies -Zmir-opt-level=0"),
    perf_stats: bool = (false, parse_bool, [UNTRACKED],
        "print some performance-related statistics"),
    query_stats: bool = (false, parse_bool, [UNTRACKED],
        "print some statistics about the query system"),
    hir_stats: bool = (false, parse_bool, [UNTRACKED],
        "print some statistics about AST and HIR"),
    always_encode_mir: bool = (false, parse_bool, [TRACKED],
        "encode MIR of all functions into the crate metadata"),
    json_rendered: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "describes how to render the `rendered` field of json diagnostics"),
    unleash_the_miri_inside_of_you: bool = (false, parse_bool, [TRACKED],
        "take the breaks off const evaluation. NOTE: this is unsound"),
    osx_rpath_install_name: bool = (false, parse_bool, [TRACKED],
        "pass `-install_name @rpath/...` to the macOS linker"),
    sanitizer: Option<Sanitizer> = (None, parse_sanitizer, [TRACKED],
                                    "use a sanitizer"),
    fuel: Option<(String, u64)> = (None, parse_optimization_fuel, [TRACKED],
        "set the optimization fuel quota for a crate"),
    print_fuel: Option<String> = (None, parse_opt_string, [TRACKED],
        "make rustc print the total optimization fuel used by a crate"),
    force_unstable_if_unmarked: bool = (false, parse_bool, [TRACKED],
        "force all crates to be `rustc_private` unstable"),
    pre_link_arg: Vec<String> = (vec![], parse_string_push, [UNTRACKED],
        "a single extra argument to prepend the linker invocation (can be used several times)"),
    pre_link_args: Option<Vec<String>> = (None, parse_opt_list, [UNTRACKED],
        "extra arguments to prepend to the linker invocation (space separated)"),
    profile: bool = (false, parse_bool, [TRACKED],
                     "insert profiling code"),
    disable_instrumentation_preinliner: bool = (false, parse_bool, [TRACKED],
        "Disable the instrumentation pre-inliner, useful for profiling / PGO."),
    relro_level: Option<RelroLevel> = (None, parse_relro_level, [TRACKED],
        "choose which RELRO level to use"),
    nll_facts: bool = (false, parse_bool, [UNTRACKED],
                       "dump facts from NLL analysis into side files"),
    nll_dont_emit_read_for_match: bool = (false, parse_bool, [UNTRACKED],
        "in match codegen, do not include FakeRead statements (used by mir-borrowck)"),
    dont_buffer_diagnostics: bool = (false, parse_bool, [UNTRACKED],
        "emit diagnostics rather than buffering (breaks NLL error downgrading, sorting)."),
    polonius: bool = (false, parse_bool, [UNTRACKED],
        "enable polonius-based borrow-checker"),
    codegen_time_graph: bool = (false, parse_bool, [UNTRACKED],
        "generate a graphical HTML report of time spent in codegen and LLVM"),
    thinlto: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "enable ThinLTO when possible"),
    inline_in_all_cgus: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "control whether `#[inline]` functions are in all CGUs"),
    tls_model: Option<String> = (None, parse_opt_string, [TRACKED],
        "choose the TLS model to use (`rustc --print tls-models` for details)"),
    saturating_float_casts: bool = (false, parse_bool, [TRACKED],
        "make float->int casts UB-free: numbers outside the integer type's range are clipped to \
         the max/min integer respectively, and NaN is mapped to 0"),
    human_readable_cgu_names: bool = (false, parse_bool, [TRACKED],
        "generate human-readable, predictable names for codegen units"),
    dep_info_omit_d_target: bool = (false, parse_bool, [TRACKED],
        "in dep-info output, omit targets for tracking dependencies of the dep-info files \
         themselves"),
    unpretty: Option<String> = (None, parse_unpretty, [UNTRACKED],
        "present the input source, unstable (and less-pretty) variants;
        valid types are any of the types for `--pretty`, as well as:
        `expanded`, `expanded,identified`,
        `expanded,hygiene` (with internal representations),
        `everybody_loops` (all function bodies replaced with `loop {}`),
        `hir` (the HIR), `hir,identified`,
        `hir,typed` (HIR with types for each node),
        `hir-tree` (dump the raw HIR),
        `mir` (the MIR), or `mir-cfg` (graphviz formatted MIR)"),
    run_dsymutil: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "run `dsymutil` and delete intermediate object files"),
    ui_testing: bool = (false, parse_bool, [UNTRACKED],
        "format compiler diagnostics in a way that's better suitable for UI testing"),
    embed_bitcode: bool = (false, parse_bool, [TRACKED],
        "embed LLVM bitcode in object files"),
    strip_debuginfo_if_disabled: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "tell the linker to strip debuginfo when building without debuginfo enabled."),
    share_generics: Option<bool> = (None, parse_opt_bool, [TRACKED],
        "make the current crate share its generic instantiations"),
    chalk: bool = (false, parse_bool, [TRACKED],
        "enable the experimental Chalk-based trait solving engine"),
    no_parallel_llvm: bool = (false, parse_bool, [UNTRACKED],
        "don't run LLVM in parallel (while keeping codegen-units and ThinLTO)"),
    no_leak_check: bool = (false, parse_bool, [UNTRACKED],
        "disables the 'leak check' for subtyping; unsound, but useful for tests"),
    no_interleave_lints: bool = (false, parse_bool, [UNTRACKED],
        "don't interleave execution of lints; allows benchmarking individual lints"),
    crate_attr: Vec<String> = (Vec::new(), parse_string_push, [TRACKED],
        "inject the given attribute in the crate"),
    self_profile: SwitchWithOptPath = (SwitchWithOptPath::Disabled,
        parse_switch_with_opt_path, [UNTRACKED],
        "run the self profiler and output the raw event data"),
    self_profile_events: Option<Vec<String>> = (None, parse_opt_comma_list, [UNTRACKED],
        "specifies which kinds of events get recorded by the self profiler"),
    emit_stack_sizes: bool = (false, parse_bool, [UNTRACKED],
        "emits a section containing stack size metadata"),
    plt: Option<bool> = (None, parse_opt_bool, [TRACKED],
          "whether to use the PLT when calling into shared libraries;
          only has effect for PIC code on systems with ELF binaries
          (default: PLT is disabled if full relro is enabled)"),
    merge_functions: Option<MergeFunctions> = (None, parse_merge_functions, [TRACKED],
        "control the operation of the MergeFunctions LLVM pass, taking
         the same values as the target option of the same name"),
    allow_features: Option<Vec<String>> = (None, parse_opt_comma_list, [TRACKED],
        "only allow the listed language features to be enabled in code (space separated)"),
    symbol_mangling_version: SymbolManglingVersion = (SymbolManglingVersion::Legacy,
        parse_symbol_mangling_version, [TRACKED],
        "which mangling version to use for symbol names"),
    binary_dep_depinfo: bool = (false, parse_bool, [TRACKED],
        "include artifacts (sysroot, crate dependencies) used during compilation in dep-info"),
    insert_sideeffect: bool = (false, parse_bool, [TRACKED],
        "fix undefined behavior when a thread doesn't eventually make progress \
         (such as entering an empty infinite loop) by inserting llvm.sideeffect"),
}

pub const fn default_lib_output() -> CrateType {
    CrateType::Rlib
}

pub fn default_configuration(sess: &Session) -> ast::CrateConfig {
    let end = &sess.target.target.target_endian;
    let arch = &sess.target.target.arch;
    let wordsz = &sess.target.target.target_pointer_width;
    let os = &sess.target.target.target_os;
    let env = &sess.target.target.target_env;
    let vendor = &sess.target.target.target_vendor;
    let min_atomic_width = sess.target.target.min_atomic_width();
    let max_atomic_width = sess.target.target.max_atomic_width();
    let atomic_cas = sess.target.target.options.atomic_cas;

    let mut ret = FxHashSet::default();
    ret.reserve(6); // the minimum number of insertions
    // Target bindings.
    ret.insert((Symbol::intern("target_os"), Some(Symbol::intern(os))));
    if let Some(ref fam) = sess.target.target.options.target_family {
        ret.insert((Symbol::intern("target_family"), Some(Symbol::intern(fam))));
        if fam == "windows" || fam == "unix" {
            ret.insert((Symbol::intern(fam), None));
        }
    }
    ret.insert((Symbol::intern("target_arch"), Some(Symbol::intern(arch))));
    ret.insert((Symbol::intern("target_endian"), Some(Symbol::intern(end))));
    ret.insert((
        Symbol::intern("target_pointer_width"),
        Some(Symbol::intern(wordsz)),
    ));
    ret.insert((Symbol::intern("target_env"), Some(Symbol::intern(env))));
    ret.insert((
        Symbol::intern("target_vendor"),
        Some(Symbol::intern(vendor)),
    ));
    if sess.target.target.options.has_elf_tls {
        ret.insert((sym::target_thread_local, None));
    }
    for &i in &[8, 16, 32, 64, 128] {
        if i >= min_atomic_width && i <= max_atomic_width {
            let mut insert_atomic = |s| {
                ret.insert((
                    sym::target_has_atomic_load_store,
                    Some(Symbol::intern(s)),
                ));
                if atomic_cas {
                    ret.insert((
                        sym::target_has_atomic,
                        Some(Symbol::intern(s))
                    ));
                }
            };
            let s = i.to_string();
            insert_atomic(&s);
            if &s == wordsz {
              insert_atomic("ptr");
            }
        }
    }
    if sess.opts.debug_assertions {
        ret.insert((Symbol::intern("debug_assertions"), None));
    }
    if sess.opts.crate_types.contains(&CrateType::ProcMacro) {
        ret.insert((sym::proc_macro, None));
    }
    ret
}

/// Converts the crate `cfg!` configuration from `String` to `Symbol`.
/// `rustc_interface::interface::Config` accepts this in the compiler configuration,
/// but the symbol interner is not yet set up then, so we must convert it later.
pub fn to_crate_config(cfg: FxHashSet<(String, Option<String>)>) -> ast::CrateConfig {
    cfg.into_iter()
       .map(|(a, b)| (Symbol::intern(&a), b.map(|b| Symbol::intern(&b))))
       .collect()
}

pub fn build_configuration(sess: &Session, mut user_cfg: ast::CrateConfig) -> ast::CrateConfig {
    // Combine the configuration requested by the session (command line) with
    // some default and generated configuration items.
    let default_cfg = default_configuration(sess);
    // If the user wants a test runner, then add the test cfg.
    if sess.opts.test {
        user_cfg.insert((sym::test, None));
    }
    user_cfg.extend(default_cfg.iter().cloned());
    user_cfg
}

pub fn build_target_config(opts: &Options, sp: &Handler) -> Config {
    let target = Target::search(&opts.target_triple).unwrap_or_else(|e| {
        sp.struct_fatal(&format!("Error loading target specification: {}", e))
          .help("Use `--print target-list` for a list of built-in targets")
          .emit();
        FatalError.raise();
    });

    let (isize_ty, usize_ty) = match &target.target_pointer_width[..] {
        "16" => (ast::IntTy::I16, ast::UintTy::U16),
        "32" => (ast::IntTy::I32, ast::UintTy::U32),
        "64" => (ast::IntTy::I64, ast::UintTy::U64),
        w => sp.fatal(&format!(
            "target specification was invalid: \
             unrecognized target-pointer-width {}",
            w
        )).raise(),
    };

    Config {
        target,
        isize_ty,
        usize_ty,
    }
}

#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum OptionStability {
    Stable,
    Unstable,
}

pub struct RustcOptGroup {
    pub apply: Box<dyn Fn(&mut getopts::Options) -> &mut getopts::Options>,
    pub name: &'static str,
    pub stability: OptionStability,
}

impl RustcOptGroup {
    pub fn is_stable(&self) -> bool {
        self.stability == OptionStability::Stable
    }

    pub fn stable<F>(name: &'static str, f: F) -> RustcOptGroup
    where
        F: Fn(&mut getopts::Options) -> &mut getopts::Options + 'static,
    {
        RustcOptGroup {
            name,
            apply: Box::new(f),
            stability: OptionStability::Stable,
        }
    }

    pub fn unstable<F>(name: &'static str, f: F) -> RustcOptGroup
    where
        F: Fn(&mut getopts::Options) -> &mut getopts::Options + 'static,
    {
        RustcOptGroup {
            name,
            apply: Box::new(f),
            stability: OptionStability::Unstable,
        }
    }
}

// The `opt` local module holds wrappers around the `getopts` API that
// adds extra rustc-specific metadata to each option; such metadata
// is exposed by .  The public
// functions below ending with `_u` are the functions that return
// *unstable* options, i.e., options that are only enabled when the
// user also passes the `-Z unstable-options` debugging flag.
mod opt {
    // The `fn flag*` etc below are written so that we can use them
    // in the future; do not warn about them not being used right now.
    #![allow(dead_code)]

    use getopts;
    use super::RustcOptGroup;

    pub type R = RustcOptGroup;
    pub type S = &'static str;

    fn stable<F>(name: S, f: F) -> R
    where
        F: Fn(&mut getopts::Options) -> &mut getopts::Options + 'static,
    {
        RustcOptGroup::stable(name, f)
    }

    fn unstable<F>(name: S, f: F) -> R
    where
        F: Fn(&mut getopts::Options) -> &mut getopts::Options + 'static,
    {
        RustcOptGroup::unstable(name, f)
    }

    fn longer(a: S, b: S) -> S {
        if a.len() > b.len() {
            a
        } else {
            b
        }
    }

    pub fn opt_s(a: S, b: S, c: S, d: S) -> R {
        stable(longer(a, b), move |opts| opts.optopt(a, b, c, d))
    }
    pub fn multi_s(a: S, b: S, c: S, d: S) -> R {
        stable(longer(a, b), move |opts| opts.optmulti(a, b, c, d))
    }
    pub fn flag_s(a: S, b: S, c: S) -> R {
        stable(longer(a, b), move |opts| opts.optflag(a, b, c))
    }
    pub fn flagopt_s(a: S, b: S, c: S, d: S) -> R {
        stable(longer(a, b), move |opts| opts.optflagopt(a, b, c, d))
    }
    pub fn flagmulti_s(a: S, b: S, c: S) -> R {
        stable(longer(a, b), move |opts| opts.optflagmulti(a, b, c))
    }

    pub fn opt(a: S, b: S, c: S, d: S) -> R {
        unstable(longer(a, b), move |opts| opts.optopt(a, b, c, d))
    }
    pub fn multi(a: S, b: S, c: S, d: S) -> R {
        unstable(longer(a, b), move |opts| opts.optmulti(a, b, c, d))
    }
    pub fn flag(a: S, b: S, c: S) -> R {
        unstable(longer(a, b), move |opts| opts.optflag(a, b, c))
    }
    pub fn flagopt(a: S, b: S, c: S, d: S) -> R {
        unstable(longer(a, b), move |opts| opts.optflagopt(a, b, c, d))
    }
    pub fn flagmulti(a: S, b: S, c: S) -> R {
        unstable(longer(a, b), move |opts| opts.optflagmulti(a, b, c))
    }
}

/// Returns the "short" subset of the rustc command line options,
/// including metadata for each option, such as whether the option is
/// part of the stable long-term interface for rustc.
pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
    vec![
        opt::flag_s("h", "help", "Display this message"),
        opt::multi_s("", "cfg", "Configure the compilation environment", "SPEC"),
        opt::multi_s(
            "L",
            "",
            "Add a directory to the library search path. The
                             optional KIND can be one of dependency, crate, native,
                             framework, or all (the default).",
            "[KIND=]PATH",
        ),
        opt::multi_s(
            "l",
            "",
            "Link the generated crate(s) to the specified native
                             library NAME. The optional KIND can be one of
                             static, framework, or dylib (the default).",
            "[KIND=]NAME",
        ),
        make_crate_type_option(),
        opt::opt_s(
            "",
            "crate-name",
            "Specify the name of the crate being built",
            "NAME",
        ),
        opt::opt_s(
            "",
            "edition",
            "Specify which edition of the compiler to use when compiling code.",
            EDITION_NAME_LIST,
        ),
        opt::multi_s(
            "",
            "emit",
            "Comma separated list of types of output for \
             the compiler to emit",
            "[asm|llvm-bc|llvm-ir|obj|metadata|link|dep-info|mir]",
        ),
        opt::multi_s(
            "",
            "print",
            "Compiler information to print on stdout",
            "[crate-name|file-names|sysroot|cfg|target-list|\
             target-cpus|target-features|relocation-models|\
             code-models|tls-models|target-spec-json|native-static-libs]",
        ),
        opt::flagmulti_s("g", "", "Equivalent to -C debuginfo=2"),
        opt::flagmulti_s("O", "", "Equivalent to -C opt-level=2"),
        opt::opt_s("o", "", "Write output to <filename>", "FILENAME"),
        opt::opt_s(
            "",
            "out-dir",
            "Write output to compiler-chosen filename \
             in <dir>",
            "DIR",
        ),
        opt::opt_s(
            "",
            "explain",
            "Provide a detailed explanation of an error \
             message",
            "OPT",
        ),
        opt::flag_s("", "test", "Build a test harness"),
        opt::opt_s(
            "",
            "target",
            "Target triple for which the code is compiled",
            "TARGET",
        ),
        opt::multi_s("W", "warn", "Set lint warnings", "OPT"),
        opt::multi_s("A", "allow", "Set lint allowed", "OPT"),
        opt::multi_s("D", "deny", "Set lint denied", "OPT"),
        opt::multi_s("F", "forbid", "Set lint forbidden", "OPT"),
        opt::multi_s(
            "",
            "cap-lints",
            "Set the most restrictive lint level. \
             More restrictive lints are capped at this \
             level",
            "LEVEL",
        ),
        opt::multi_s("C", "codegen", "Set a codegen option", "OPT[=VALUE]"),
        opt::flag_s("V", "version", "Print version info and exit"),
        opt::flag_s("v", "verbose", "Use verbose output"),
    ]
}

/// Returns all rustc command line options, including metadata for
/// each option, such as whether the option is part of the stable
/// long-term interface for rustc.
pub fn rustc_optgroups() -> Vec<RustcOptGroup> {
    let mut opts = rustc_short_optgroups();
    opts.extend(vec![
        opt::multi_s(
            "",
            "extern",
            "Specify where an external rust library is located",
            "NAME[=PATH]",
        ),
        opt::multi_s(
            "",
            "extern-private",
            "Specify where an extern rust library is located, marking it as a private dependency",
            "NAME=PATH",
        ),
        opt::opt_s("", "sysroot", "Override the system root", "PATH"),
        opt::multi("Z", "", "Set internal debugging options", "FLAG"),
        opt::opt_s(
            "",
            "error-format",
            "How errors and other messages are produced",
            "human|json|short",
        ),
        opt::multi_s(
            "",
            "json",
            "Configure the JSON output of the compiler",
            "CONFIG",
        ),
        opt::opt_s(
            "",
            "color",
            "Configure coloring of output:
                                 auto   = colorize, if output goes to a tty (default);
                                 always = always colorize output;
                                 never  = never colorize output",
            "auto|always|never",
        ),
        opt::opt(
            "",
            "pretty",
            "Pretty-print the input instead of compiling;
                  valid types are: `normal` (un-annotated source),
                  `expanded` (crates expanded), or
                  `expanded,identified` (fully parenthesized, AST nodes with IDs).",
            "TYPE",
        ),
        opt::multi_s(
            "",
            "remap-path-prefix",
            "Remap source names in all output (compiler messages and output files)",
            "FROM=TO",
        ),
    ]);
    opts
}

pub fn get_cmd_lint_options(matches: &getopts::Matches,
                            error_format: ErrorOutputType)
                            -> (Vec<(String, lint::Level)>, bool, Option<lint::Level>) {
    let mut lint_opts = vec![];
    let mut describe_lints = false;

    for &level in &[lint::Allow, lint::Warn, lint::Deny, lint::Forbid] {
        for lint_name in matches.opt_strs(level.as_str()) {
            if lint_name == "help" {
                describe_lints = true;
            } else {
                lint_opts.push((lint_name.replace("-", "_"), level));
            }
        }
    }

    let lint_cap = matches.opt_str("cap-lints").map(|cap| {
        lint::Level::from_str(&cap)
            .unwrap_or_else(|| early_error(error_format, &format!("unknown lint level: `{}`", cap)))
    });
    (lint_opts, describe_lints, lint_cap)
}

/// Parses the `--color` flag.
pub fn parse_color(matches: &getopts::Matches) -> ColorConfig {
    match matches.opt_str("color").as_ref().map(|s| &s[..]) {
        Some("auto") => ColorConfig::Auto,
        Some("always") => ColorConfig::Always,
        Some("never") => ColorConfig::Never,

        None => ColorConfig::Auto,

        Some(arg) => early_error(
            ErrorOutputType::default(),
            &format!(
                "argument for `--color` must be auto, \
                 always or never (instead was `{}`)",
                arg
            ),
        ),
    }
}

/// Parse the `--json` flag.
///
/// The first value returned is how to render JSON diagnostics, and the second
/// is whether or not artifact notifications are enabled.
pub fn parse_json(matches: &getopts::Matches) -> (HumanReadableErrorType, bool) {
    let mut json_rendered: fn(ColorConfig) -> HumanReadableErrorType =
        HumanReadableErrorType::Default;
    let mut json_color = ColorConfig::Never;
    let mut json_artifact_notifications = false;
    for option in matches.opt_strs("json") {
        // For now conservatively forbid `--color` with `--json` since `--json`
        // won't actually be emitting any colors and anything colorized is
        // embedded in a diagnostic message anyway.
        if matches.opt_str("color").is_some() {
            early_error(
                ErrorOutputType::default(),
                "cannot specify the `--color` option with `--json`",
            );
        }

        for sub_option in option.split(',') {
            match sub_option {
                "diagnostic-short" => json_rendered = HumanReadableErrorType::Short,
                "diagnostic-rendered-ansi" => json_color = ColorConfig::Always,
                "artifacts" => json_artifact_notifications = true,
                s => {
                    early_error(
                        ErrorOutputType::default(),
                        &format!("unknown `--json` option `{}`", s),
                    )
                }
            }
        }
    }
    (json_rendered(json_color), json_artifact_notifications)
}

/// Parses the `--error-format` flag.
pub fn parse_error_format(
    matches: &getopts::Matches,
    color: ColorConfig,
    json_rendered: HumanReadableErrorType,
) -> ErrorOutputType {
    // We need the `opts_present` check because the driver will send us Matches
    // with only stable options if no unstable options are used. Since error-format
    // is unstable, it will not be present. We have to use `opts_present` not
    // `opt_present` because the latter will panic.
    let error_format = if matches.opts_present(&["error-format".to_owned()]) {
        match matches.opt_str("error-format").as_ref().map(|s| &s[..]) {
            None |
            Some("human") => ErrorOutputType::HumanReadable(HumanReadableErrorType::Default(color)),
            Some("human-annotate-rs") => {
                ErrorOutputType::HumanReadable(HumanReadableErrorType::AnnotateSnippet(color))
            },
            Some("json") => ErrorOutputType::Json { pretty: false, json_rendered },
            Some("pretty-json") => ErrorOutputType::Json { pretty: true, json_rendered },
            Some("short") => ErrorOutputType::HumanReadable(HumanReadableErrorType::Short(color)),

            Some(arg) => early_error(
                ErrorOutputType::HumanReadable(HumanReadableErrorType::Default(color)),
                &format!(
                    "argument for `--error-format` must be `human`, `json` or \
                     `short` (instead was `{}`)",
                    arg
                ),
            ),
        }
    } else {
        ErrorOutputType::HumanReadable(HumanReadableErrorType::Default(color))
    };

    match error_format {
        ErrorOutputType::Json { .. } => {}

        // Conservatively require that the `--json` argument is coupled with
        // `--error-format=json`. This means that `--json` is specified we
        // should actually be emitting JSON blobs.
        _ if matches.opt_strs("json").len() > 0 => {
            early_error(
                ErrorOutputType::default(),
                "using `--json` requires also using `--error-format=json`",
            );
        }

        _ => {}
    }

    return error_format;
}

fn parse_crate_edition(matches: &getopts::Matches) -> Edition {
    let edition = match matches.opt_str("edition") {
        Some(arg) => Edition::from_str(&arg).unwrap_or_else(|_|
            early_error(
                ErrorOutputType::default(),
                &format!(
                    "argument for `--edition` must be one of: \
                     {}. (instead was `{}`)",
                    EDITION_NAME_LIST,
                    arg
                ),
            ),
        ),
        None => DEFAULT_EDITION,
    };

    if !edition.is_stable() && !nightly_options::is_nightly_build() {
        early_error(
                ErrorOutputType::default(),
                &format!(
                    "edition {} is unstable and only \
                     available for nightly builds of rustc.",
                    edition,
                )
        )
    }

    edition
}

fn check_debug_option_stability(
    debugging_opts: &DebuggingOptions,
    error_format: ErrorOutputType,
    json_rendered: HumanReadableErrorType,
) {
    if !debugging_opts.unstable_options {
        if let ErrorOutputType::Json { pretty: true, json_rendered } = error_format {
            early_error(
                ErrorOutputType::Json { pretty: false, json_rendered },
                "`--error-format=pretty-json` is unstable",
            );
        }
        if let ErrorOutputType::HumanReadable(HumanReadableErrorType::AnnotateSnippet(_)) =
            error_format {
            early_error(
                ErrorOutputType::Json { pretty: false, json_rendered },
                "`--error-format=human-annotate-rs` is unstable",
            );
        }
    }
}

fn parse_output_types(
    debugging_opts: &DebuggingOptions,
    matches: &getopts::Matches,
    error_format: ErrorOutputType,
) -> OutputTypes {
    let mut output_types = BTreeMap::new();
    if !debugging_opts.parse_only {
        for list in matches.opt_strs("emit") {
            for output_type in list.split(',') {
                let mut parts = output_type.splitn(2, '=');
                let shorthand = parts.next().unwrap();
                let output_type = OutputType::from_shorthand(shorthand).unwrap_or_else(||
                    early_error(
                        error_format,
                        &format!(
                            "unknown emission type: `{}` - expected one of: {}",
                            shorthand,
                            OutputType::shorthands_display(),
                        ),
                    ),
                );
                let path = parts.next().map(PathBuf::from);
                output_types.insert(output_type, path);
            }
        }
    };
    if output_types.is_empty() {
        output_types.insert(OutputType::Exe, None);
    }
    OutputTypes(output_types)
}

fn should_override_cgus_and_disable_thinlto(
    output_types: &OutputTypes,
    matches: &getopts::Matches,
    error_format: ErrorOutputType,
    mut codegen_units: Option<usize>,
) -> (bool, Option<usize>) {
    let mut disable_thinlto = false;
    // Issue #30063: if user requests LLVM-related output to one
    // particular path, disable codegen-units.
    let incompatible: Vec<_> = output_types.0
        .iter()
        .map(|ot_path| ot_path.0)
        .filter(|ot| !ot.is_compatible_with_codegen_units_and_single_output_file())
        .map(|ot| ot.shorthand())
        .collect();
    if !incompatible.is_empty() {
        match codegen_units {
            Some(n) if n > 1 => {
                if matches.opt_present("o") {
                    for ot in &incompatible {
                        early_warn(
                            error_format,
                            &format!(
                                "`--emit={}` with `-o` incompatible with \
                                 `-C codegen-units=N` for N > 1",
                                ot
                            ),
                        );
                    }
                    early_warn(error_format, "resetting to default -C codegen-units=1");
                    codegen_units = Some(1);
                    disable_thinlto = true;
                }
            }
            _ => {
                codegen_units = Some(1);
                disable_thinlto = true;
            }
        }
    }

    if codegen_units == Some(0) {
        early_error(
            error_format,
            "value for codegen units must be a positive non-zero integer",
        );
    }

    (disable_thinlto, codegen_units)
}

fn check_thread_count(debugging_opts: &DebuggingOptions, error_format: ErrorOutputType) {
    if debugging_opts.threads == 0 {
        early_error(
            error_format,
            "value for threads must be a positive non-zero integer",
        );
    }

    if debugging_opts.threads > 1 && debugging_opts.fuel.is_some() {
        early_error(
            error_format,
            "optimization fuel is incompatible with multiple threads",
        );
    }
}

fn select_incremental_path(
    debugging_opts: &DebuggingOptions,
    cg: &CodegenOptions,
    error_format: ErrorOutputType,
) -> Option<PathBuf> {
    match (&debugging_opts.incremental, &cg.incremental) {
        (Some(path1), Some(path2)) => {
            if path1 != path2 {
                early_error(
                    error_format,
                    &format!(
                        "conflicting paths for `-Z incremental` and \
                         `-C incremental` specified: {} versus {}",
                        path1, path2
                    ),
                );
            } else {
                Some(path1)
            }
        }
        (Some(path), None) => Some(path),
        (None, Some(path)) => Some(path),
        (None, None) => None,
    }.map(|m| PathBuf::from(m))
}

fn collect_print_requests(
    cg: &mut CodegenOptions,
    dopts: &mut DebuggingOptions,
    matches: &getopts::Matches,
    error_format: ErrorOutputType,
) -> Vec<PrintRequest> {
    let mut prints = Vec::<PrintRequest>::new();
    if cg.target_cpu.as_ref().map_or(false, |s| s == "help") {
        prints.push(PrintRequest::TargetCPUs);
        cg.target_cpu = None;
    };
    if cg.target_feature == "help" {
        prints.push(PrintRequest::TargetFeatures);
        cg.target_feature = String::new();
    }
    if cg.relocation_model.as_ref().map_or(false, |s| s == "help") {
        prints.push(PrintRequest::RelocationModels);
        cg.relocation_model = None;
    }
    if cg.code_model.as_ref().map_or(false, |s| s == "help") {
        prints.push(PrintRequest::CodeModels);
        cg.code_model = None;
    }
    if dopts
        .tls_model
        .as_ref()
        .map_or(false, |s| s == "help")
    {
        prints.push(PrintRequest::TlsModels);
        dopts.tls_model = None;
    }

    prints.extend(matches.opt_strs("print").into_iter().map(|s| match &*s {
        "crate-name" => PrintRequest::CrateName,
        "file-names" => PrintRequest::FileNames,
        "sysroot" => PrintRequest::Sysroot,
        "cfg" => PrintRequest::Cfg,
        "target-list" => PrintRequest::TargetList,
        "target-cpus" => PrintRequest::TargetCPUs,
        "target-features" => PrintRequest::TargetFeatures,
        "relocation-models" => PrintRequest::RelocationModels,
        "code-models" => PrintRequest::CodeModels,
        "tls-models" => PrintRequest::TlsModels,
        "native-static-libs" => PrintRequest::NativeStaticLibs,
        "target-spec-json" => {
            if dopts.unstable_options {
                PrintRequest::TargetSpec
            } else {
                early_error(
                    error_format,
                    "the `-Z unstable-options` flag must also be passed to \
                     enable the target-spec-json print option",
                );
            }
        }
        req => early_error(error_format, &format!("unknown print request `{}`", req)),
    }));

    prints
}

fn parse_target_triple(matches: &getopts::Matches, error_format: ErrorOutputType) -> TargetTriple {
    match matches.opt_str("target") {
        Some(target) if target.ends_with(".json") => {
            let path = Path::new(&target);
            TargetTriple::from_path(&path).unwrap_or_else(|_|
                early_error(error_format, &format!("target file {:?} does not exist", path)))
        }
        Some(target) => TargetTriple::TargetTriple(target),
        _ => TargetTriple::from_triple(host_triple()),
    }
}

fn parse_opt_level(
    matches: &getopts::Matches,
    cg: &CodegenOptions,
    error_format: ErrorOutputType,
) -> OptLevel {
    // The `-O` and `-C opt-level` flags specify the same setting, so we want to be able
    // to use them interchangeably. However, because they're technically different flags,
    // we need to work out manually which should take precedence if both are supplied (i.e.
    // the rightmost flag). We do this by finding the (rightmost) position of both flags and
    // comparing them. Note that if a flag is not found, its position will be `None`, which
    // always compared less than `Some(_)`.
    let max_o = matches.opt_positions("O").into_iter().max();
    let max_c = matches.opt_strs_pos("C").into_iter().flat_map(|(i, s)| {
        if let Some("opt-level") = s.splitn(2, '=').next() {
            Some(i)
        } else {
            None
        }
    }).max();
    if max_o > max_c {
        OptLevel::Default
    } else {
        match cg.opt_level.as_ref().map(String::as_ref) {
            None => OptLevel::No,
            Some("0") => OptLevel::No,
            Some("1") => OptLevel::Less,
            Some("2") => OptLevel::Default,
            Some("3") => OptLevel::Aggressive,
            Some("s") => OptLevel::Size,
            Some("z") => OptLevel::SizeMin,
            Some(arg) => {
                early_error(
                    error_format,
                    &format!(
                        "optimization level needs to be \
                            between 0-3, s or z (instead was `{}`)",
                        arg
                    ),
                );
            }
        }
    }
}

fn select_debuginfo(
    matches: &getopts::Matches,
    cg: &CodegenOptions,
    error_format: ErrorOutputType,
) -> DebugInfo {
    let max_g = matches.opt_positions("g").into_iter().max();
    let max_c = matches.opt_strs_pos("C").into_iter().flat_map(|(i, s)| {
        if let Some("debuginfo") = s.splitn(2, '=').next() {
            Some(i)
        } else {
            None
        }
    }).max();
    if max_g > max_c {
        DebugInfo::Full
    } else {
        match cg.debuginfo {
            None | Some(0) => DebugInfo::None,
            Some(1) => DebugInfo::Limited,
            Some(2) => DebugInfo::Full,
            Some(arg) => {
                early_error(
                    error_format,
                    &format!(
                        "debug info level needs to be between \
                         0-2 (instead was `{}`)",
                        arg
                    ),
                );
            }
        }
    }
}

fn parse_libs(
    matches: &getopts::Matches,
    error_format: ErrorOutputType,
) -> Vec<(String, Option<String>, Option<cstore::NativeLibraryKind>)> {
    matches
        .opt_strs("l")
        .into_iter()
        .map(|s| {
            // Parse string of the form "[KIND=]lib[:new_name]",
            // where KIND is one of "dylib", "framework", "static".
            let mut parts = s.splitn(2, '=');
            let kind = parts.next().unwrap();
            let (name, kind) = match (parts.next(), kind) {
                (None, name) => (name, None),
                (Some(name), "dylib") => (name, Some(cstore::NativeUnknown)),
                (Some(name), "framework") => (name, Some(cstore::NativeFramework)),
                (Some(name), "static") => (name, Some(cstore::NativeStatic)),
                (Some(name), "static-nobundle") => (name, Some(cstore::NativeStaticNobundle)),
                (_, s) => {
                    early_error(
                        error_format,
                        &format!(
                            "unknown library kind `{}`, expected \
                             one of dylib, framework, or static",
                            s
                        ),
                    );
                }
            };
            if kind == Some(cstore::NativeStaticNobundle) && !nightly_options::is_nightly_build() {
                early_error(
                    error_format,
                    &format!(
                        "the library kind 'static-nobundle' is only \
                         accepted on the nightly compiler"
                    ),
                );
            }
            let mut name_parts = name.splitn(2, ':');
            let name = name_parts.next().unwrap();
            let new_name = name_parts.next();
            (name.to_owned(), new_name.map(|n| n.to_owned()), kind)
        })
        .collect()
}

fn parse_borrowck_mode(dopts: &DebuggingOptions, error_format: ErrorOutputType) -> BorrowckMode {
    match dopts.borrowck.as_ref().map(|s| &s[..]) {
        None | Some("migrate") => BorrowckMode::Migrate,
        Some("mir") => BorrowckMode::Mir,
        Some(m) => early_error(error_format, &format!("unknown borrowck mode `{}`", m)),
    }
}

fn parse_externs(
    matches: &getopts::Matches,
    debugging_opts: &DebuggingOptions,
    error_format: ErrorOutputType,
) -> Externs {
    if matches.opt_present("extern-private") && !debugging_opts.unstable_options {
        early_error(
            ErrorOutputType::default(),
            "'--extern-private' is unstable and only \
            available for nightly builds of rustc."
        )
    }

    // We start out with a `Vec<(Option<String>, bool)>>`,
    // and later convert it into a `BTreeSet<(Option<String>, bool)>`
    // This allows to modify entries in-place to set their correct
    // 'public' value.
    let mut externs: BTreeMap<String, ExternEntry> = BTreeMap::new();
    for (arg, private) in matches.opt_strs("extern").into_iter().map(|v| (v, false))
        .chain(matches.opt_strs("extern-private").into_iter().map(|v| (v, true))) {

        let mut parts = arg.splitn(2, '=');
        let name = parts.next().unwrap_or_else(||
            early_error(error_format, "--extern value must not be empty"));
        let location = parts.next().map(|s| s.to_string());

        let entry = externs
            .entry(name.to_owned())
            .or_default();


        entry.locations.insert(location.clone());

        // Crates start out being not private,
        // and go to being private if we see an '--extern-private'
        // flag
        entry.is_private_dep |= private;
    }
    Externs(externs)
}

fn parse_remap_path_prefix(
    matches: &getopts::Matches,
    error_format: ErrorOutputType
) -> Vec<(PathBuf, PathBuf)> {
    matches
        .opt_strs("remap-path-prefix")
        .into_iter()
        .map(|remap| {
            let mut parts = remap.rsplitn(2, '='); // reverse iterator
            let to = parts.next();
            let from = parts.next();
            match (from, to) {
                (Some(from), Some(to)) => (PathBuf::from(from), PathBuf::from(to)),
                _ => early_error(
                    error_format,
                    "--remap-path-prefix must contain '=' between FROM and TO",
                ),
            }
        })
        .collect()
}

pub fn build_session_options(matches: &getopts::Matches) -> Options {
    let color = parse_color(matches);

    let edition = parse_crate_edition(matches);

    let (json_rendered, json_artifact_notifications) = parse_json(matches);

    let error_format = parse_error_format(matches, color, json_rendered);

    let unparsed_crate_types = matches.opt_strs("crate-type");
    let crate_types = parse_crate_types_from_list(unparsed_crate_types)
        .unwrap_or_else(|e| early_error(error_format, &e[..]));

    let (lint_opts, describe_lints, lint_cap) = get_cmd_lint_options(matches, error_format);

    let mut debugging_opts = build_debugging_options(matches, error_format);
    check_debug_option_stability(&debugging_opts, error_format, json_rendered);

    let output_types = parse_output_types(&debugging_opts, matches, error_format);

    let mut cg = build_codegen_options(matches, error_format);
    let (disable_thinlto, codegen_units) = should_override_cgus_and_disable_thinlto(
        &output_types,
        matches,
        error_format,
        cg.codegen_units,
    );

    check_thread_count(&debugging_opts, error_format);

    let incremental = select_incremental_path(&debugging_opts, &cg, error_format);

    if debugging_opts.profile && incremental.is_some() {
        early_error(
            error_format,
            "can't instrument with gcov profiling when compiling incrementally",
        );
    }

    if cg.profile_generate.enabled() && cg.profile_use.is_some() {
        early_error(
            error_format,
            "options `-C profile-generate` and `-C profile-use` are exclusive",
        );
    }

    let prints = collect_print_requests(
        &mut cg,
        &mut debugging_opts,
        matches,
        error_format,
    );

    let cg = cg;

    let sysroot_opt = matches.opt_str("sysroot").map(|m| PathBuf::from(&m));
    let target_triple = parse_target_triple(matches, error_format);
    let opt_level = parse_opt_level(matches, &cg, error_format);
    // The `-g` and `-C debuginfo` flags specify the same setting, so we want to be able
    // to use them interchangeably. See the note above (regarding `-O` and `-C opt-level`)
    // for more details.
    let debug_assertions = cg.debug_assertions.unwrap_or(opt_level == OptLevel::No);
    let debuginfo = select_debuginfo(matches, &cg, error_format);

    let mut search_paths = vec![];
    for s in &matches.opt_strs("L") {
        search_paths.push(SearchPath::from_cli_opt(&s[..], error_format));
    }

    let libs = parse_libs(matches, error_format);

    let test = matches.opt_present("test");

    let borrowck_mode = parse_borrowck_mode(&debugging_opts, error_format);

    if !cg.remark.is_empty() && debuginfo == DebugInfo::None {
        early_warn(
            error_format,
            "-C remark requires \"-C debuginfo=n\" to show source locations",
        );
    }

    let externs = parse_externs(matches, &debugging_opts, error_format);

    let crate_name = matches.opt_str("crate-name");

    let remap_path_prefix = parse_remap_path_prefix(matches, error_format);

    let pretty = parse_pretty(matches, &debugging_opts, error_format);

    Options {
        crate_types,
        optimize: opt_level,
        debuginfo,
        lint_opts,
        lint_cap,
        describe_lints,
        output_types,
        search_paths,
        maybe_sysroot: sysroot_opt,
        target_triple,
        test,
        incremental,
        debugging_opts,
        prints,
        borrowck_mode,
        cg,
        error_format,
        externs,
        crate_name,
        alt_std_name: None,
        libs,
        unstable_features: UnstableFeatures::from_environment(),
        debug_assertions,
        actually_rustdoc: false,
        cli_forced_codegen_units: codegen_units,
        cli_forced_thinlto_off: disable_thinlto,
        remap_path_prefix,
        edition,
        json_artifact_notifications,
        pretty,
    }
}

fn parse_pretty(
    matches: &getopts::Matches,
    debugging_opts: &DebuggingOptions,
    efmt: ErrorOutputType,
) -> Option<(PpMode, Option<UserIdentifiedItem>)> {
    let pretty = if debugging_opts.unstable_options {
        matches.opt_default("pretty", "normal").map(|a| {
            // stable pretty-print variants only
            parse_pretty_inner(efmt, &a, false)
        })
    } else {
        None
    };

    return if pretty.is_none() {
        debugging_opts.unpretty.as_ref().map(|a| {
            // extended with unstable pretty-print variants
            parse_pretty_inner(efmt, &a, true)
        })
    } else {
        pretty
    };

    fn parse_pretty_inner(
        efmt: ErrorOutputType,
        name: &str,
        extended: bool,
    ) -> (PpMode, Option<UserIdentifiedItem>) {
        use PpMode::*;
        use PpSourceMode::*;
        let mut split = name.splitn(2, '=');
        let first = split.next().unwrap();
        let opt_second = split.next();
        let first = match (first, extended) {
            ("normal", _) => PpmSource(PpmNormal),
            ("identified", _) => PpmSource(PpmIdentified),
            ("everybody_loops", true) => PpmSource(PpmEveryBodyLoops),
            ("expanded", _) => PpmSource(PpmExpanded),
            ("expanded,identified", _) => PpmSource(PpmExpandedIdentified),
            ("expanded,hygiene", _) => PpmSource(PpmExpandedHygiene),
            ("hir", true) => PpmHir(PpmNormal),
            ("hir,identified", true) => PpmHir(PpmIdentified),
            ("hir,typed", true) => PpmHir(PpmTyped),
            ("hir-tree", true) => PpmHirTree(PpmNormal),
            ("mir", true) => PpmMir,
            ("mir-cfg", true) => PpmMirCFG,
            _ => {
                if extended {
                    early_error(efmt, &format!("argument to `unpretty` must be one of `normal`, \
                                        `expanded`, `identified`, `expanded,identified`, \
                                        `expanded,hygiene`, `everybody_loops`, \
                                        `hir`, `hir,identified`, `hir,typed`, `hir-tree`, \
                                        `mir` or `mir-cfg`; got {}",
                                        name));
                } else {
                    early_error(efmt, &format!("argument to `pretty` must be one of `normal`, \
                                        `expanded`, `identified`, or `expanded,identified`; got {}",
                                        name));
                }
            }
        };
        let opt_second = opt_second.and_then(|s| s.parse::<UserIdentifiedItem>().ok());
        (first, opt_second)
    }
}

pub fn make_crate_type_option() -> RustcOptGroup {
    opt::multi_s(
        "",
        "crate-type",
        "Comma separated list of types of crates
                                for the compiler to emit",
        "[bin|lib|rlib|dylib|cdylib|staticlib|proc-macro]",
    )
}

pub fn parse_crate_types_from_list(list_list: Vec<String>) -> Result<Vec<CrateType>, String> {
    let mut crate_types: Vec<CrateType> = Vec::new();
    for unparsed_crate_type in &list_list {
        for part in unparsed_crate_type.split(',') {
            let new_part = match part {
                "lib" => default_lib_output(),
                "rlib" => CrateType::Rlib,
                "staticlib" => CrateType::Staticlib,
                "dylib" => CrateType::Dylib,
                "cdylib" => CrateType::Cdylib,
                "bin" => CrateType::Executable,
                "proc-macro" => CrateType::ProcMacro,
                _ => return Err(format!("unknown crate type: `{}`", part))
            };
            if !crate_types.contains(&new_part) {
                crate_types.push(new_part)
            }
        }
    }

    Ok(crate_types)
}

pub mod nightly_options {
    use getopts;
    use syntax::feature_gate::UnstableFeatures;
    use super::{ErrorOutputType, OptionStability, RustcOptGroup};
    use crate::session::early_error;

    pub fn is_unstable_enabled(matches: &getopts::Matches) -> bool {
        is_nightly_build()
            && matches
                .opt_strs("Z")
                .iter()
                .any(|x| *x == "unstable-options")
    }

    pub fn is_nightly_build() -> bool {
        UnstableFeatures::from_environment().is_nightly_build()
    }

    pub fn check_nightly_options(matches: &getopts::Matches, flags: &[RustcOptGroup]) {
        let has_z_unstable_option = matches
            .opt_strs("Z")
            .iter()
            .any(|x| *x == "unstable-options");
        let really_allows_unstable_options =
            UnstableFeatures::from_environment().is_nightly_build();

        for opt in flags.iter() {
            if opt.stability == OptionStability::Stable {
                continue;
            }
            if !matches.opt_present(opt.name) {
                continue;
            }
            if opt.name != "Z" && !has_z_unstable_option {
                early_error(
                    ErrorOutputType::default(),
                    &format!(
                        "the `-Z unstable-options` flag must also be passed to enable \
                         the flag `{}`",
                        opt.name
                    ),
                );
            }
            if really_allows_unstable_options {
                continue;
            }
            match opt.stability {
                OptionStability::Unstable => {
                    let msg = format!(
                        "the option `{}` is only accepted on the \
                         nightly compiler",
                        opt.name
                    );
                    early_error(ErrorOutputType::default(), &msg);
                }
                OptionStability::Stable => {}
            }
        }
    }
}

impl fmt::Display for CrateType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match *self {
            CrateType::Executable => "bin".fmt(f),
            CrateType::Dylib => "dylib".fmt(f),
            CrateType::Rlib => "rlib".fmt(f),
            CrateType::Staticlib => "staticlib".fmt(f),
            CrateType::Cdylib => "cdylib".fmt(f),
            CrateType::ProcMacro => "proc-macro".fmt(f),
        }
    }
}

#[derive(Copy, Clone, PartialEq, Debug)]
pub enum PpSourceMode {
    PpmNormal,
    PpmEveryBodyLoops,
    PpmExpanded,
    PpmIdentified,
    PpmExpandedIdentified,
    PpmExpandedHygiene,
    PpmTyped,
}

#[derive(Copy, Clone, PartialEq, Debug)]
pub enum PpMode {
    PpmSource(PpSourceMode),
    PpmHir(PpSourceMode),
    PpmHirTree(PpSourceMode),
    PpmMir,
    PpmMirCFG,
}

impl PpMode {
    pub fn needs_ast_map(&self, opt_uii: &Option<UserIdentifiedItem>) -> bool {
        use PpMode::*;
        use PpSourceMode::*;
        match *self {
            PpmSource(PpmNormal) |
            PpmSource(PpmEveryBodyLoops) |
            PpmSource(PpmIdentified) => opt_uii.is_some(),

            PpmSource(PpmExpanded) |
            PpmSource(PpmExpandedIdentified) |
            PpmSource(PpmExpandedHygiene) |
            PpmHir(_) |
            PpmHirTree(_) |
            PpmMir |
            PpmMirCFG => true,
            PpmSource(PpmTyped) => panic!("invalid state"),
        }
    }

    pub fn needs_analysis(&self) -> bool {
        use PpMode::*;
        match *self {
            PpmMir | PpmMirCFG => true,
            _ => false,
        }
    }
}

#[derive(Clone, Debug)]
pub enum UserIdentifiedItem {
    ItemViaNode(ast::NodeId),
    ItemViaPath(Vec<String>),
}

impl FromStr for UserIdentifiedItem {
    type Err = ();
    fn from_str(s: &str) -> Result<UserIdentifiedItem, ()> {
        use UserIdentifiedItem::*;
        Ok(s.parse()
            .map(ast::NodeId::from_u32)
            .map(ItemViaNode)
            .unwrap_or_else(|_| ItemViaPath(s.split("::").map(|s| s.to_string()).collect())))
    }
}

pub enum NodesMatchingUII<'a> {
    NodesMatchingDirect(std::option::IntoIter<ast::NodeId>),
    NodesMatchingSuffix(Box<dyn Iterator<Item = ast::NodeId> + 'a>),
}

impl<'a> Iterator for NodesMatchingUII<'a> {
    type Item = ast::NodeId;

    fn next(&mut self) -> Option<ast::NodeId> {
        use NodesMatchingUII::*;
        match self {
            &mut NodesMatchingDirect(ref mut iter) => iter.next(),
            &mut NodesMatchingSuffix(ref mut iter) => iter.next(),
        }
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        use NodesMatchingUII::*;
        match self {
            &NodesMatchingDirect(ref iter) => iter.size_hint(),
            &NodesMatchingSuffix(ref iter) => iter.size_hint(),
        }
    }
}

impl UserIdentifiedItem {
    pub fn reconstructed_input(&self) -> String {
        use UserIdentifiedItem::*;
        match *self {
            ItemViaNode(node_id) => node_id.to_string(),
            ItemViaPath(ref parts) => parts.join("::"),
        }
    }

    pub fn all_matching_node_ids<'a, 'hir>(&'a self,
                                       map: &'a hir_map::Map<'hir>)
                                       -> NodesMatchingUII<'a> {
        use UserIdentifiedItem::*;
        use NodesMatchingUII::*;
        match *self {
            ItemViaNode(node_id) => NodesMatchingDirect(Some(node_id).into_iter()),
            ItemViaPath(ref parts) => {
                NodesMatchingSuffix(Box::new(map.nodes_matching_suffix(&parts)))
            }
        }
    }

    pub fn to_one_node_id(self,
                      user_option: &str,
                      sess: &Session,
                      map: &hir_map::Map<'_>)
                      -> ast::NodeId {
        let fail_because = |is_wrong_because| -> ast::NodeId {
            let message = format!("{} needs NodeId (int) or unique path suffix (b::c::d); got \
                                   {}, which {}",
                                  user_option,
                                  self.reconstructed_input(),
                                  is_wrong_because);
            sess.fatal(&message)
        };

        let mut saw_node = ast::DUMMY_NODE_ID;
        let mut seen = 0;
        for node in self.all_matching_node_ids(map) {
            saw_node = node;
            seen += 1;
            if seen > 1 {
                fail_because("does not resolve uniquely");
            }
        }
        if seen == 0 {
            fail_because("does not resolve to any item");
        }

        assert!(seen == 1);
        return saw_node;
    }
}

/// Command-line arguments passed to the compiler have to be incorporated with
/// the dependency tracking system for incremental compilation. This module
/// provides some utilities to make this more convenient.
///
/// The values of all command-line arguments that are relevant for dependency
/// tracking are hashed into a single value that determines whether the
/// incremental compilation cache can be re-used or not. This hashing is done
/// via the `DepTrackingHash` trait defined below, since the standard `Hash`
/// implementation might not be suitable (e.g., arguments are stored in a `Vec`,
/// the hash of which is order dependent, but we might not want the order of
/// arguments to make a difference for the hash).
///
/// However, since the value provided by `Hash::hash` often *is* suitable,
/// especially for primitive types, there is the
/// `impl_dep_tracking_hash_via_hash!()` macro that allows to simply reuse the
/// `Hash` implementation for `DepTrackingHash`. It's important though that
/// we have an opt-in scheme here, so one is hopefully forced to think about
/// how the hash should be calculated when adding a new command-line argument.
mod dep_tracking {
    use crate::lint;
    use crate::middle::cstore;
    use std::collections::BTreeMap;
    use std::hash::Hash;
    use std::path::PathBuf;
    use std::collections::hash_map::DefaultHasher;
    use super::{CrateType, DebugInfo, ErrorOutputType, OptLevel, OutputTypes,
                Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath,
                SymbolManglingVersion};
    use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel, TargetTriple};
    use syntax::edition::Edition;
    use syntax::feature_gate::UnstableFeatures;

    pub trait DepTrackingHash {
        fn hash(&self, hasher: &mut DefaultHasher, error_format: ErrorOutputType);
    }

    macro_rules! impl_dep_tracking_hash_via_hash {
        ($t:ty) => (
            impl DepTrackingHash for $t {
                fn hash(&self, hasher: &mut DefaultHasher, _: ErrorOutputType) {
                    Hash::hash(self, hasher);
                }
            }
        )
    }

    macro_rules! impl_dep_tracking_hash_for_sortable_vec_of {
        ($t:ty) => (
            impl DepTrackingHash for Vec<$t> {
                fn hash(&self, hasher: &mut DefaultHasher, error_format: ErrorOutputType) {
                    let mut elems: Vec<&$t> = self.iter().collect();
                    elems.sort();
                    Hash::hash(&elems.len(), hasher);
                    for (index, elem) in elems.iter().enumerate() {
                        Hash::hash(&index, hasher);
                        DepTrackingHash::hash(*elem, hasher, error_format);
                    }
                }
            }
        );
    }

    impl_dep_tracking_hash_via_hash!(bool);
    impl_dep_tracking_hash_via_hash!(usize);
    impl_dep_tracking_hash_via_hash!(u64);
    impl_dep_tracking_hash_via_hash!(String);
    impl_dep_tracking_hash_via_hash!(PathBuf);
    impl_dep_tracking_hash_via_hash!(lint::Level);
    impl_dep_tracking_hash_via_hash!(Option<bool>);
    impl_dep_tracking_hash_via_hash!(Option<usize>);
    impl_dep_tracking_hash_via_hash!(Option<String>);
    impl_dep_tracking_hash_via_hash!(Option<(String, u64)>);
    impl_dep_tracking_hash_via_hash!(Option<Vec<String>>);
    impl_dep_tracking_hash_via_hash!(Option<MergeFunctions>);
    impl_dep_tracking_hash_via_hash!(Option<PanicStrategy>);
    impl_dep_tracking_hash_via_hash!(Option<RelroLevel>);
    impl_dep_tracking_hash_via_hash!(Option<lint::Level>);
    impl_dep_tracking_hash_via_hash!(Option<PathBuf>);
    impl_dep_tracking_hash_via_hash!(Option<cstore::NativeLibraryKind>);
    impl_dep_tracking_hash_via_hash!(CrateType);
    impl_dep_tracking_hash_via_hash!(MergeFunctions);
    impl_dep_tracking_hash_via_hash!(PanicStrategy);
    impl_dep_tracking_hash_via_hash!(RelroLevel);
    impl_dep_tracking_hash_via_hash!(Passes);
    impl_dep_tracking_hash_via_hash!(OptLevel);
    impl_dep_tracking_hash_via_hash!(LtoCli);
    impl_dep_tracking_hash_via_hash!(DebugInfo);
    impl_dep_tracking_hash_via_hash!(UnstableFeatures);
    impl_dep_tracking_hash_via_hash!(OutputTypes);
    impl_dep_tracking_hash_via_hash!(cstore::NativeLibraryKind);
    impl_dep_tracking_hash_via_hash!(Sanitizer);
    impl_dep_tracking_hash_via_hash!(Option<Sanitizer>);
    impl_dep_tracking_hash_via_hash!(TargetTriple);
    impl_dep_tracking_hash_via_hash!(Edition);
    impl_dep_tracking_hash_via_hash!(LinkerPluginLto);
    impl_dep_tracking_hash_via_hash!(SwitchWithOptPath);
    impl_dep_tracking_hash_via_hash!(SymbolManglingVersion);

    impl_dep_tracking_hash_for_sortable_vec_of!(String);
    impl_dep_tracking_hash_for_sortable_vec_of!(PathBuf);
    impl_dep_tracking_hash_for_sortable_vec_of!(CrateType);
    impl_dep_tracking_hash_for_sortable_vec_of!((String, lint::Level));
    impl_dep_tracking_hash_for_sortable_vec_of!((
        String,
        Option<String>,
        Option<cstore::NativeLibraryKind>
    ));
    impl_dep_tracking_hash_for_sortable_vec_of!((String, u64));

    impl<T1, T2> DepTrackingHash for (T1, T2)
    where
        T1: DepTrackingHash,
        T2: DepTrackingHash,
    {
        fn hash(&self, hasher: &mut DefaultHasher, error_format: ErrorOutputType) {
            Hash::hash(&0, hasher);
            DepTrackingHash::hash(&self.0, hasher, error_format);
            Hash::hash(&1, hasher);
            DepTrackingHash::hash(&self.1, hasher, error_format);
        }
    }

    impl<T1, T2, T3> DepTrackingHash for (T1, T2, T3)
    where
        T1: DepTrackingHash,
        T2: DepTrackingHash,
        T3: DepTrackingHash,
    {
        fn hash(&self, hasher: &mut DefaultHasher, error_format: ErrorOutputType) {
            Hash::hash(&0, hasher);
            DepTrackingHash::hash(&self.0, hasher, error_format);
            Hash::hash(&1, hasher);
            DepTrackingHash::hash(&self.1, hasher, error_format);
            Hash::hash(&2, hasher);
            DepTrackingHash::hash(&self.2, hasher, error_format);
        }
    }

    // This is a stable hash because BTreeMap is a sorted container
    pub fn stable_hash(
        sub_hashes: BTreeMap<&'static str, &dyn DepTrackingHash>,
        hasher: &mut DefaultHasher,
        error_format: ErrorOutputType,
    ) {
        for (key, sub_hash) in sub_hashes {
            // Using Hash::hash() instead of DepTrackingHash::hash() is fine for
            // the keys, as they are just plain strings
            Hash::hash(&key.len(), hasher);
            Hash::hash(key, hasher);
            sub_hash.hash(hasher, error_format);
        }
    }
}