rust/src/librustc/session/config.rs

// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

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

pub use self::EntryFnType::*;
pub use self::CrateType::*;
pub use self::Passes::*;
pub use self::OptLevel::*;
pub use self::OutputType::*;
pub use self::DebugInfoLevel::*;

use session::{early_error, early_warn, Session};

use rustc_back::target::Target;
use lint;
use metadata::cstore;

use syntax::ast;
use syntax::ast::{IntTy, UintTy};
use syntax::attr;
use syntax::attr::AttrMetaMethods;
use syntax::diagnostic::{ColorConfig, Auto, Always, Never, SpanHandler};
use syntax::parse;
use syntax::parse::token::InternedString;

use std::collections::HashMap;
use std::collections::hash_map::{Occupied, Vacant};
use getopts::{optopt, optmulti, optflag, optflagopt};
use getopts;
use std::cell::{RefCell};
use std::fmt;

use llvm;

pub struct Config {
    pub target: Target,
    pub int_type: IntTy,
    pub uint_type: UintTy,
}

#[deriving(Clone, PartialEq)]
pub enum OptLevel {
    No, // -O0
    Less, // -O1
    Default, // -O2
    Aggressive // -O3
}

impl Copy for OptLevel {}

#[deriving(Clone, PartialEq)]
pub enum DebugInfoLevel {
    NoDebugInfo,
    LimitedDebugInfo,
    FullDebugInfo,
}

impl Copy for DebugInfoLevel {}

#[deriving(Clone, PartialEq, PartialOrd, Ord, Eq)]
pub enum OutputType {
    OutputTypeBitcode,
    OutputTypeAssembly,
    OutputTypeLlvmAssembly,
    OutputTypeObject,
    OutputTypeExe,
}

impl Copy for OutputType {}

#[deriving(Clone)]
pub struct Options {
    // The crate config requested for the session, which may be combined
    // with additional crate configurations during the compile process
    pub crate_types: Vec<CrateType>,

    pub gc: bool,
    pub optimize: OptLevel,
    pub debuginfo: DebugInfoLevel,
    pub lint_opts: Vec<(String, lint::Level)>,
    pub describe_lints: bool,
    pub output_types: Vec<OutputType> ,
    // This was mutable for rustpkg, which updates search paths based on the
    // parsed code. It remains mutable in case its replacements wants to use
    // this.
    pub addl_lib_search_paths: RefCell<Vec<Path>>,
    pub libs: Vec<(String, cstore::NativeLibraryKind)>,
    pub maybe_sysroot: Option<Path>,
    pub target_triple: String,
    // User-specified cfg meta items. The compiler itself will add additional
    // items to the crate config, and during parsing the entire crate config
    // will be added to the crate AST node.  This should not be used for
    // anything except building the full crate config prior to parsing.
    pub cfg: ast::CrateConfig,
    pub test: bool,
    pub parse_only: bool,
    pub no_trans: bool,
    pub no_analysis: bool,
    pub debugging_opts: u64,
    /// Whether to write dependency files. It's (enabled, optional filename).
    pub write_dependency_info: (bool, Option<Path>),
    /// Crate id-related things to maybe print. It's (crate_name, crate_file_name).
    pub print_metas: (bool, bool),
    pub cg: CodegenOptions,
    pub color: ColorConfig,
    pub externs: HashMap<String, Vec<String>>,
    pub crate_name: Option<String>,
    /// An optional name to use as the crate for std during std injection,
    /// written `extern crate std = "name"`. Default to "std". Used by
    /// out-of-tree drivers.
    pub alt_std_name: Option<String>
}

pub enum Input {
    /// Load source from file
    File(Path),
    /// The string is the source
    Str(String)
}

impl Input {
    pub fn filestem(&self) -> String {
        match *self {
            Input::File(ref ifile) => ifile.filestem_str().unwrap().to_string(),
            Input::Str(_) => "rust_out".to_string(),
        }
    }
}

#[deriving(Clone)]
pub struct OutputFilenames {
    pub out_directory: Path,
    pub out_filestem: String,
    pub single_output_file: Option<Path>,
    pub extra: String,
}

impl OutputFilenames {
    pub fn path(&self, flavor: OutputType) -> Path {
        match self.single_output_file {
            Some(ref path) => return path.clone(),
            None => {}
        }
        self.temp_path(flavor)
    }

    pub fn temp_path(&self, flavor: OutputType) -> Path {
        let base = self.out_directory.join(self.filestem());
        match flavor {
            OutputTypeBitcode => base.with_extension("bc"),
            OutputTypeAssembly => base.with_extension("s"),
            OutputTypeLlvmAssembly => base.with_extension("ll"),
            OutputTypeObject => base.with_extension("o"),
            OutputTypeExe => base,
        }
    }

    pub fn with_extension(&self, extension: &str) -> Path {
        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")
}

/// Some reasonable defaults
pub fn basic_options() -> Options {
    Options {
        crate_types: Vec::new(),
        gc: false,
        optimize: No,
        debuginfo: NoDebugInfo,
        lint_opts: Vec::new(),
        describe_lints: false,
        output_types: Vec::new(),
        addl_lib_search_paths: RefCell::new(Vec::new()),
        maybe_sysroot: None,
        target_triple: host_triple().to_string(),
        cfg: Vec::new(),
        test: false,
        parse_only: false,
        no_trans: false,
        no_analysis: false,
        debugging_opts: 0,
        write_dependency_info: (false, None),
        print_metas: (false, false),
        cg: basic_codegen_options(),
        color: Auto,
        externs: HashMap::new(),
        crate_name: None,
        alt_std_name: None,
        libs: Vec::new(),
    }
}

// The type of entry function, so
// users can have their own entry
// functions that don't start a
// scheduler
#[deriving(PartialEq)]
pub enum EntryFnType {
    EntryMain,
    EntryStart,
    EntryNone,
}

impl Copy for EntryFnType {}

#[deriving(PartialEq, PartialOrd, Clone, Ord, Eq, Hash)]
pub enum CrateType {
    CrateTypeExecutable,
    CrateTypeDylib,
    CrateTypeRlib,
    CrateTypeStaticlib,
}

impl Copy for CrateType {}

macro_rules! debugging_opts(
    ([ $opt:ident ] $cnt:expr ) => (
        pub const $opt: u64 = 1 << $cnt;
    );
    ([ $opt:ident, $($rest:ident),* ] $cnt:expr ) => (
        pub const $opt: u64 = 1 << $cnt;
        debugging_opts!([ $($rest),* ] $cnt + 1)
    )
)

debugging_opts!(
    [
        VERBOSE,
        TIME_PASSES,
        COUNT_LLVM_INSNS,
        TIME_LLVM_PASSES,
        TRANS_STATS,
        ASM_COMMENTS,
        NO_VERIFY,
        BORROWCK_STATS,
        NO_LANDING_PADS,
        DEBUG_LLVM,
        SHOW_SPAN,
        COUNT_TYPE_SIZES,
        META_STATS,
        GC,
        PRINT_LINK_ARGS,
        PRINT_LLVM_PASSES,
        AST_JSON,
        AST_JSON_NOEXPAND,
        LS,
        SAVE_ANALYSIS,
        PRINT_MOVE_FRAGMENTS,
        FLOWGRAPH_PRINT_LOANS,
        FLOWGRAPH_PRINT_MOVES,
        FLOWGRAPH_PRINT_ASSIGNS,
        FLOWGRAPH_PRINT_ALL,
        PRINT_SYSROOT,
        PRINT_REGION_GRAPH
    ]
    0
)

pub fn debugging_opts_map() -> Vec<(&'static str, &'static str, u64)> {
    vec![("verbose", "in general, enable more debug printouts", VERBOSE),
     ("time-passes", "measure time of each rustc pass", TIME_PASSES),
     ("count-llvm-insns", "count where LLVM \
                           instrs originate", COUNT_LLVM_INSNS),
     ("time-llvm-passes", "measure time of each LLVM pass",
      TIME_LLVM_PASSES),
     ("trans-stats", "gather trans statistics", TRANS_STATS),
     ("asm-comments", "generate comments into the assembly (may change behavior)",
      ASM_COMMENTS),
     ("no-verify", "skip LLVM verification", NO_VERIFY),
     ("borrowck-stats", "gather borrowck statistics",  BORROWCK_STATS),
     ("no-landing-pads", "omit landing pads for unwinding",
      NO_LANDING_PADS),
     ("debug-llvm", "enable debug output from LLVM", DEBUG_LLVM),
     ("show-span", "show spans for compiler debugging", SHOW_SPAN),
     ("count-type-sizes", "count the sizes of aggregate types",
      COUNT_TYPE_SIZES),
     ("meta-stats", "gather metadata statistics", META_STATS),
     ("print-link-args", "Print the arguments passed to the linker",
      PRINT_LINK_ARGS),
     ("gc", "Garbage collect shared data (experimental)", GC),
     ("print-llvm-passes",
      "Prints the llvm optimization passes being run",
      PRINT_LLVM_PASSES),
     ("ast-json", "Print the AST as JSON and halt", AST_JSON),
     ("ast-json-noexpand", "Print the pre-expansion AST as JSON and halt", AST_JSON_NOEXPAND),
     ("ls", "List the symbols defined by a library crate", LS),
     ("save-analysis", "Write syntax and type analysis information \
                        in addition to normal output", SAVE_ANALYSIS),
     ("print-move-fragments", "Print out move-fragment data for every fn",
      PRINT_MOVE_FRAGMENTS),
     ("flowgraph-print-loans", "Include loan analysis data in \
                       --pretty flowgraph output", FLOWGRAPH_PRINT_LOANS),
     ("flowgraph-print-moves", "Include move analysis data in \
                       --pretty flowgraph output", FLOWGRAPH_PRINT_MOVES),
     ("flowgraph-print-assigns", "Include assignment analysis data in \
                       --pretty flowgraph output", FLOWGRAPH_PRINT_ASSIGNS),
     ("flowgraph-print-all", "Include all dataflow analysis data in \
                       --pretty flowgraph output", FLOWGRAPH_PRINT_ALL),
     ("print-sysroot", "Print the sysroot as used by this rustc invocation",
      PRINT_SYSROOT),
     ("print-region-graph", "Prints region inference graph. \
                             Use with RUST_REGION_GRAPH=help for more info",
      PRINT_REGION_GRAPH)]
}

#[deriving(Clone)]
pub enum Passes {
    SomePasses(Vec<String>),
    AllPasses,
}

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

/// Declare a macro that will define all CodegenOptions 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 in order 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! cgoptions(
    ($($opt:ident : $t:ty = ($init:expr, $parse:ident, $desc:expr)),* ,) =>
(
    #[deriving(Clone)]
    pub struct CodegenOptions { $(pub $opt: $t),* }

    pub fn basic_codegen_options() -> CodegenOptions {
        CodegenOptions { $($opt: $init),* }
    }

    pub type CodegenSetter = fn(&mut CodegenOptions, v: Option<&str>) -> bool;
    pub const CG_OPTIONS: &'static [(&'static str, CodegenSetter,
                                     Option<&'static str>, &'static str)] =
        &[ $( (stringify!($opt), cgsetters::$opt, cg_type_descs::$parse, $desc) ),* ];

    #[allow(non_upper_case_globals)]
    mod cg_type_descs {
        pub const parse_bool: Option<&'static str> = None;
        pub const parse_opt_bool: Option<&'static str> = None;
        pub const parse_string: Option<&'static str> = Some("a string");
        pub const parse_opt_string: Option<&'static str> = Some("a string");
        pub const parse_list: Option<&'static str> = Some("a space-separated list of strings");
        pub const parse_opt_list: Option<&'static str> = Some("a space-separated list of strings");
        pub const parse_uint: Option<&'static str> = Some("a number");
        pub const parse_passes: Option<&'static str> =
            Some("a space-separated list of passes, or `all`");
    }

    mod cgsetters {
        use super::{CodegenOptions, Passes, SomePasses, AllPasses};

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

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

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

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

cgoptions!(
    ar: Option<String> = (None, parse_opt_string,
        "tool to assemble archives with"),
    linker: Option<String> = (None, parse_opt_string,
        "system linker to link outputs with"),
    link_args: Option<Vec<String>> = (None, parse_opt_list,
        "extra arguments to pass to the linker (space separated)"),
    lto: bool = (false, parse_bool,
        "perform LLVM link-time optimizations"),
    target_cpu: Option<String> = (None, parse_opt_string,
        "select target processor (llc -mcpu=help for details)"),
    target_feature: String = ("".to_string(), parse_string,
        "target specific attributes (llc -mattr=help for details)"),
    passes: Vec<String> = (Vec::new(), parse_list,
        "a list of extra LLVM passes to run (space separated)"),
    llvm_args: Vec<String> = (Vec::new(), parse_list,
        "a list of arguments to pass to llvm (space separated)"),
    save_temps: bool = (false, parse_bool,
        "save all temporary output files during compilation"),
    rpath: bool = (false, parse_bool,
        "set rpath values in libs/exes"),
    no_prepopulate_passes: bool = (false, parse_bool,
        "don't pre-populate the pass manager with a list of passes"),
    no_vectorize_loops: bool = (false, parse_bool,
        "don't run the loop vectorization optimization passes"),
    no_vectorize_slp: bool = (false, parse_bool,
        "don't run LLVM's SLP vectorization pass"),
    soft_float: bool = (false, parse_bool,
        "generate software floating point library calls"),
    prefer_dynamic: bool = (false, parse_bool,
        "prefer dynamic linking to static linking"),
    no_integrated_as: bool = (false, parse_bool,
        "use an external assembler rather than LLVM's integrated one"),
    no_redzone: Option<bool> = (None, parse_opt_bool,
        "disable the use of the redzone"),
    relocation_model: Option<String> = (None, parse_opt_string,
         "choose the relocation model to use (llc -relocation-model for details)"),
    code_model: Option<String> = (None, parse_opt_string,
         "choose the code model to use (llc -code-model for details)"),
    metadata: Vec<String> = (Vec::new(), parse_list,
         "metadata to mangle symbol names with"),
    extra_filename: String = ("".to_string(), parse_string,
         "extra data to put in each output filename"),
    codegen_units: uint = (1, parse_uint,
        "divide crate into N units to optimize in parallel"),
    remark: Passes = (SomePasses(Vec::new()), parse_passes,
        "print remarks for these optimization passes (space separated, or \"all\")"),
    no_stack_check: bool = (false, parse_bool,
        "disable checks for stack exhaustion (a memory-safety hazard!)"),
)

pub fn build_codegen_options(matches: &getopts::Matches) -> CodegenOptions
{
    let mut cg = basic_codegen_options();
    for option in matches.opt_strs("C").into_iter() {
        let mut iter = option.splitn(1, '=');
        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 CG_OPTIONS.iter() {
            if option_to_lookup != candidate { continue }
            if !setter(&mut cg, value) {
                match (value, opt_type_desc) {
                    (Some(..), None) => {
                        early_error(format!("codegen option `{}` takes no \
                                             value", key).as_slice())
                    }
                    (None, Some(type_desc)) => {
                        early_error(format!("codegen option `{0}` requires \
                                             {1} (-C {0}=<value>)",
                                            key, type_desc).as_slice())
                    }
                    (Some(value), Some(type_desc)) => {
                        early_error(format!("incorrect value `{}` for codegen \
                                             option `{}` - {} was expected",
                                             value, key, type_desc).as_slice())
                    }
                    (None, None) => unreachable!()
                }
            }
            found = true;
            break;
        }
        if !found {
            early_error(format!("unknown codegen option: `{}`",
                                key).as_slice());
        }
    }
    return cg;
}

pub fn default_lib_output() -> CrateType {
    CrateTypeRlib
}

pub fn default_configuration(sess: &Session) -> ast::CrateConfig {
    use syntax::parse::token::intern_and_get_ident as intern;

    let end = sess.target.target.target_endian.as_slice();
    let arch = sess.target.target.arch.as_slice();
    let wordsz = sess.target.target.target_word_size.as_slice();
    let os = sess.target.target.target_os.as_slice();

    let fam = match sess.target.target.options.is_like_windows {
        true  => InternedString::new("windows"),
        false => InternedString::new("unix")
    };

    let mk = attr::mk_name_value_item_str;
    return vec!(// Target bindings.
         attr::mk_word_item(fam.clone()),
         mk(InternedString::new("target_os"), intern(os)),
         mk(InternedString::new("target_family"), fam),
         mk(InternedString::new("target_arch"), intern(arch)),
         mk(InternedString::new("target_endian"), intern(end)),
         mk(InternedString::new("target_word_size"),
            intern(wordsz))
    );
}

pub fn append_configuration(cfg: &mut ast::CrateConfig,
                            name: InternedString) {
    if !cfg.iter().any(|mi| mi.name() == name) {
        cfg.push(attr::mk_word_item(name))
    }
}

pub fn build_configuration(sess: &Session) -> ast::CrateConfig {
    // Combine the configuration requested by the session (command line) with
    // some default and generated configuration items
    let default_cfg = default_configuration(sess);
    let mut user_cfg = sess.opts.cfg.clone();
    // If the user wants a test runner, then add the test cfg
    if sess.opts.test {
        append_configuration(&mut user_cfg, InternedString::new("test"))
    }
    let mut v = user_cfg.into_iter().collect::<Vec<_>>();
    v.push_all(default_cfg.as_slice());
    v
}

pub fn build_target_config(opts: &Options, sp: &SpanHandler) -> Config {
    let target = match Target::search(opts.target_triple.as_slice()) {
        Ok(t) => t,
        Err(e) => {
            sp.handler().fatal((format!("Error loading target specification: {}", e)).as_slice());
    }
    };

    let (int_type, uint_type) = match target.target_word_size.as_slice() {
        "32" => (ast::TyI32, ast::TyU32),
        "64" => (ast::TyI64, ast::TyU64),
        w    => sp.handler().fatal((format!("target specification was invalid: unrecognized \
                                            target-word-size {}", w)).as_slice())
    };

    Config {
        target: target,
        int_type: int_type,
        uint_type: uint_type,
    }
}

// rustc command line options
pub fn optgroups() -> Vec<getopts::OptGroup> {
    vec!(
        optflag("h", "help", "Display this message"),
        optmulti("", "cfg", "Configure the compilation environment", "SPEC"),
        optmulti("L", "",   "Add a directory to the library search path", "PATH"),
        optmulti("l", "",   "Link the generated crate(s) to the specified native
                             library NAME. The optional KIND can be one of,
                             static, dylib, or framework. If omitted, dylib is
                             assumed.", "NAME[:KIND]"),
        optmulti("", "crate-type", "Comma separated list of types of crates
                                    for the compiler to emit",
                 "[bin|lib|rlib|dylib|staticlib]"),
        optmulti("", "emit", "Comma separated list of types of output for the compiler to emit",
                 "[asm|bc|ir|obj|link]"),
        optopt("", "crate-name", "Specify the name of the crate being built",
               "NAME"),
        optflag("", "print-crate-name", "Output the crate name and exit"),
        optflag("", "print-file-name", "Output the file(s) that would be written if compilation \
              continued and exit"),
        optflag("", "crate-file-name", "deprecated in favor of --print-file-name"),
        optflag("g",  "",  "Equivalent to --debuginfo=2"),
        optopt("",  "debuginfo",  "Emit DWARF debug info to the objects created:
             0 = no debug info,
             1 = line-tables only (for stacktraces and breakpoints),
             2 = full debug info with variable and type information (same as -g)", "LEVEL"),
        optflag("", "no-trans", "Run all passes except translation; no output"),
        optflag("", "no-analysis",
              "Parse and expand the source, but run no analysis and produce no output"),
        optflag("O", "", "Equivalent to --opt-level=2"),
        optopt("o", "", "Write output to <filename>", "FILENAME"),
        optopt("", "opt-level", "Optimize with possible levels 0-3", "LEVEL"),
        optopt( "",  "out-dir", "Write output to compiler-chosen filename in <dir>", "DIR"),
        optflag("", "parse-only", "Parse only; do not compile, assemble, or link"),
        optopt("", "explain", "Provide a detailed explanation of an error message", "OPT"),
        optflagopt("", "pretty",
                   "Pretty-print the input instead of compiling;
                   valid types are: `normal` (un-annotated source),
                   `expanded` (crates expanded),
                   `typed` (crates expanded, with type annotations),
                   `expanded,identified` (fully parenthesized, AST nodes with IDs), or
                   `flowgraph=<nodeid>` (graphviz formatted flowgraph for node)",
                 "TYPE"),
        optflagopt("", "dep-info",
                 "Output dependency info to <filename> after compiling, \
                  in a format suitable for use by Makefiles", "FILENAME"),
        optopt("", "sysroot", "Override the system root", "PATH"),
        optflag("", "test", "Build a test harness"),
        optopt("", "target", "Target triple cpu-manufacturer-kernel[-os]
                            to compile for (see chapter 3.4 of http://www.sourceware.org/autobook/
                            for details)", "TRIPLE"),
        optmulti("W", "warn", "Set lint warnings", "OPT"),
        optmulti("A", "allow", "Set lint allowed", "OPT"),
        optmulti("D", "deny", "Set lint denied", "OPT"),
        optmulti("F", "forbid", "Set lint forbidden", "OPT"),
        optmulti("C", "codegen", "Set a codegen option", "OPT[=VALUE]"),
        optmulti("Z", "", "Set internal debugging options", "FLAG"),
        optflagopt("v", "version", "Print version info and exit", "verbose"),
        optopt("", "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"),
        optmulti("", "extern", "Specify where an external rust library is located",
                 "NAME=PATH"),
    )
}


// Convert strings provided as --cfg [cfgspec] into a crate_cfg
pub fn parse_cfgspecs(cfgspecs: Vec<String> ) -> ast::CrateConfig {
    cfgspecs.into_iter().map(|s| {
        parse::parse_meta_from_source_str("cfgspec".to_string(),
                                          s.to_string(),
                                          Vec::new(),
                                          &parse::new_parse_sess())
    }).collect::<ast::CrateConfig>()
}

pub fn build_session_options(matches: &getopts::Matches) -> Options {

    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(e.as_slice()));

    let parse_only = matches.opt_present("parse-only");
    let no_trans = matches.opt_present("no-trans");
    let no_analysis = matches.opt_present("no-analysis");

    let mut lint_opts = vec!();
    let mut describe_lints = false;

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

    let mut debugging_opts = 0;
    let debug_flags = matches.opt_strs("Z");
    let debug_map = debugging_opts_map();
    for debug_flag in debug_flags.iter() {
        let mut this_bit = 0;
        for &(name, _, bit) in debug_map.iter() {
            if name == *debug_flag {
                this_bit = bit;
                break;
            }
        }
        if this_bit == 0 {
            early_error(format!("unknown debug flag: {}",
                                *debug_flag).as_slice())
        }
        debugging_opts |= this_bit;
    }

    if debugging_opts & DEBUG_LLVM != 0 {
        unsafe { llvm::LLVMSetDebug(1); }
    }

    let mut output_types = Vec::new();
    if !parse_only && !no_trans {
        let unparsed_output_types = matches.opt_strs("emit");
        for unparsed_output_type in unparsed_output_types.iter() {
            for part in unparsed_output_type.split(',') {
                let output_type = match part.as_slice() {
                    "asm"  => OutputTypeAssembly,
                    "ir"   => OutputTypeLlvmAssembly,
                    "bc"   => OutputTypeBitcode,
                    "obj"  => OutputTypeObject,
                    "link" => OutputTypeExe,
                    _ => {
                        early_error(format!("unknown emission type: `{}`",
                                            part).as_slice())
                    }
                };
                output_types.push(output_type)
            }
        }
    };
    output_types.sort();
    output_types.dedup();
    if output_types.len() == 0 {
        output_types.push(OutputTypeExe);
    }

    let sysroot_opt = matches.opt_str("sysroot").map(|m| Path::new(m));
    let target = matches.opt_str("target").unwrap_or(
        host_triple().to_string());
    let opt_level = {
        if matches.opt_present("O") {
            if matches.opt_present("opt-level") {
                early_error("-O and --opt-level both provided");
            }
            Default
        } else if matches.opt_present("opt-level") {
            match matches.opt_str("opt-level").as_ref().map(|s| s.as_slice()) {
                None      |
                Some("0") => No,
                Some("1") => Less,
                Some("2") => Default,
                Some("3") => Aggressive,
                Some(arg) => {
                    early_error(format!("optimization level needs to be \
                                         between 0-3 (instead was `{}`)",
                                        arg).as_slice());
                }
            }
        } else {
            No
        }
    };
    let gc = debugging_opts & GC != 0;
    let debuginfo = if matches.opt_present("g") {
        if matches.opt_present("debuginfo") {
            early_error("-g and --debuginfo both provided");
        }
        FullDebugInfo
    } else if matches.opt_present("debuginfo") {
        match matches.opt_str("debuginfo").as_ref().map(|s| s.as_slice()) {
            Some("0") => NoDebugInfo,
            Some("1") => LimitedDebugInfo,
            None      |
            Some("2") => FullDebugInfo,
            Some(arg) => {
                early_error(format!("debug info level needs to be between \
                                     0-2 (instead was `{}`)",
                                    arg).as_slice());
            }
        }
    } else {
        NoDebugInfo
    };

    let addl_lib_search_paths = matches.opt_strs("L").iter().map(|s| {
        Path::new(s.as_slice())
    }).collect();

    let libs = matches.opt_strs("l").into_iter().map(|s| {
        let mut parts = s.rsplitn(1, ':');
        let kind = parts.next().unwrap();
        let (name, kind) = match (parts.next(), kind) {
            (None, name) |
            (Some(name), "dylib") => (name, cstore::NativeUnknown),
            (Some(name), "framework") => (name, cstore::NativeFramework),
            (Some(name), "static") => (name, cstore::NativeStatic),
            (_, s) => {
                early_error(format!("unknown library kind `{}`, expected \
                                     one of dylib, framework, or static",
                                    s).as_slice());
            }
        };
        (name.to_string(), kind)
    }).collect();

    let cfg = parse_cfgspecs(matches.opt_strs("cfg"));
    let test = matches.opt_present("test");
    let write_dependency_info = (matches.opt_present("dep-info"),
                                 matches.opt_str("dep-info")
                                        .map(|p| Path::new(p)));

    let print_metas = (matches.opt_present("print-crate-name"),
                       matches.opt_present("print-file-name") ||
                       matches.opt_present("crate-file-name"));
    if matches.opt_present("crate-file-name") {
        early_warn("the --crate-file-name argument has been renamed to \
                    --print-file-name");
    }
    let cg = build_codegen_options(matches);

    if !cg.remark.is_empty() && debuginfo == NoDebugInfo {
        early_warn("-C remark will not show source locations without --debuginfo");
    }

    let color = match matches.opt_str("color").as_ref().map(|s| s.as_slice()) {
        Some("auto")   => Auto,
        Some("always") => Always,
        Some("never")  => Never,

        None => Auto,

        Some(arg) => {
            early_error(format!("argument for --color must be auto, always \
                                 or never (instead was `{}`)",
                                arg).as_slice())
        }
    };

    let mut externs = HashMap::new();
    for arg in matches.opt_strs("extern").iter() {
        let mut parts = arg.splitn(1, '=');
        let name = match parts.next() {
            Some(s) => s,
            None => early_error("--extern value must not be empty"),
        };
        let location = match parts.next() {
            Some(s) => s,
            None => early_error("--extern value must be of the format `foo=bar`"),
        };

        match externs.entry(name.to_string()) {
            Vacant(entry) => { entry.set(vec![location.to_string()]); },
            Occupied(mut entry) => { entry.get_mut().push(location.to_string()); },
        }
    }

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

    Options {
        crate_types: crate_types,
        gc: gc,
        optimize: opt_level,
        debuginfo: debuginfo,
        lint_opts: lint_opts,
        describe_lints: describe_lints,
        output_types: output_types,
        addl_lib_search_paths: RefCell::new(addl_lib_search_paths),
        maybe_sysroot: sysroot_opt,
        target_triple: target,
        cfg: cfg,
        test: test,
        parse_only: parse_only,
        no_trans: no_trans,
        no_analysis: no_analysis,
        debugging_opts: debugging_opts,
        write_dependency_info: write_dependency_info,
        print_metas: print_metas,
        cg: cg,
        color: color,
        externs: externs,
        crate_name: crate_name,
        alt_std_name: None,
        libs: libs,
    }
}

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.iter() {
        for part in unparsed_crate_type.split(',') {
            let new_part = match part {
                "lib"       => default_lib_output(),
                "rlib"      => CrateTypeRlib,
                "staticlib" => CrateTypeStaticlib,
                "dylib"     => CrateTypeDylib,
                "bin"       => CrateTypeExecutable,
                _ => {
                    return Err(format!("unknown crate type: `{}`",
                                       part));
                }
            };
            crate_types.push(new_part)
        }
    }

    return Ok(crate_types);
}

impl fmt::Show for CrateType {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            CrateTypeExecutable => "bin".fmt(f),
            CrateTypeDylib => "dylib".fmt(f),
            CrateTypeRlib => "rlib".fmt(f),
            CrateTypeStaticlib => "staticlib".fmt(f)
        }
    }
}

#[cfg(test)]
mod test {

    use session::config::{build_configuration, optgroups, build_session_options};
    use session::build_session;

    use getopts::getopts;
    use syntax::attr;
    use syntax::attr::AttrMetaMethods;
    use syntax::diagnostics;

    // When the user supplies --test we should implicitly supply --cfg test
    #[test]
    fn test_switch_implies_cfg_test() {
        let matches =
            &match getopts(&["--test".to_string()], optgroups().as_slice()) {
              Ok(m) => m,
              Err(f) => panic!("test_switch_implies_cfg_test: {}", f)
            };
        let registry = diagnostics::registry::Registry::new(&[]);
        let sessopts = build_session_options(matches);
        let sess = build_session(sessopts, None, registry);
        let cfg = build_configuration(&sess);
        assert!((attr::contains_name(cfg.as_slice(), "test")));
    }

    // When the user supplies --test and --cfg test, don't implicitly add
    // another --cfg test
    #[test]
    fn test_switch_implies_cfg_test_unless_cfg_test() {
        let matches =
            &match getopts(&["--test".to_string(), "--cfg=test".to_string()],
                           optgroups().as_slice()) {
              Ok(m) => m,
              Err(f) => {
                panic!("test_switch_implies_cfg_test_unless_cfg_test: {}", f)
              }
            };
        let registry = diagnostics::registry::Registry::new(&[]);
        let sessopts = build_session_options(matches);
        let sess = build_session(sessopts, None, registry);
        let cfg = build_configuration(&sess);
        let mut test_items = cfg.iter().filter(|m| m.name() == "test");
        assert!(test_items.next().is_some());
        assert!(test_items.next().is_none());
    }

    #[test]
    fn test_can_print_warnings() {
        {
            let matches = getopts(&[
                "-Awarnings".to_string()
            ], optgroups().as_slice()).unwrap();
            let registry = diagnostics::registry::Registry::new(&[]);
            let sessopts = build_session_options(&matches);
            let sess = build_session(sessopts, None, registry);
            assert!(!sess.can_print_warnings);
        }

        {
            let matches = getopts(&[
                "-Awarnings".to_string(),
                "-Dwarnings".to_string()
            ], optgroups().as_slice()).unwrap();
            let registry = diagnostics::registry::Registry::new(&[]);
            let sessopts = build_session_options(&matches);
            let sess = build_session(sessopts, None, registry);
            assert!(sess.can_print_warnings);
        }

        {
            let matches = getopts(&[
                "-Adead_code".to_string()
            ], optgroups().as_slice()).unwrap();
            let registry = diagnostics::registry::Registry::new(&[]);
            let sessopts = build_session_options(&matches);
            let sess = build_session(sessopts, None, registry);
            assert!(sess.can_print_warnings);
        }
    }
}