path: root/src/tools/compiletest/src/header.rs

use std::collections::HashSet;
use std::env;
use std::fs::File;
use std::io::prelude::*;
use std::io::BufReader;
use std::path::{Path, PathBuf};
use std::process::Command;

use tracing::*;

use crate::common::{CompareMode, Config, Debugger, FailMode, Mode, PassMode};
use crate::util;
use crate::{extract_cdb_version, extract_gdb_version};

#[cfg(test)]
mod tests;

/// The result of parse_cfg_name_directive.
#[derive(Clone, Copy, PartialEq, Debug)]
enum ParsedNameDirective {
    /// No match.
    NoMatch,
    /// Match.
    Match,
}

/// Properties which must be known very early, before actually running
/// the test.
#[derive(Default)]
pub struct EarlyProps {
    pub aux: Vec<String>,
    pub aux_crate: Vec<(String, String)>,
    pub revisions: Vec<String>,
}

impl EarlyProps {
    pub fn from_file(config: &Config, testfile: &Path) -> Self {
        let file = File::open(testfile).expect("open test file to parse earlyprops");
        Self::from_reader(config, testfile, file)
    }

    pub fn from_reader<R: Read>(config: &Config, testfile: &Path, rdr: R) -> Self {
        let mut props = EarlyProps::default();
        iter_header(testfile, rdr, &mut |_, ln| {
            config.push_name_value_directive(ln, directives::AUX_BUILD, &mut props.aux, |r| {
                r.trim().to_string()
            });
            config.push_name_value_directive(
                ln,
                directives::AUX_CRATE,
                &mut props.aux_crate,
                Config::parse_aux_crate,
            );
            config.parse_and_update_revisions(ln, &mut props.revisions);
        });
        return props;
    }
}

#[derive(Clone, Debug)]
pub struct TestProps {
    // Lines that should be expected, in order, on standard out
    pub error_patterns: Vec<String>,
    // Regexes that should be expected, in order, on standard out
    pub regex_error_patterns: Vec<String>,
    // Extra flags to pass to the compiler
    pub compile_flags: Vec<String>,
    // Extra flags to pass when the compiled code is run (such as --bench)
    pub run_flags: Option<String>,
    // If present, the name of a file that this test should match when
    // pretty-printed
    pub pp_exact: Option<PathBuf>,
    // Other crates that should be compiled (typically from the same
    // directory as the test, but for backwards compatibility reasons
    // we also check the auxiliary directory)
    pub aux_builds: Vec<String>,
    // Similar to `aux_builds`, but a list of NAME=somelib.rs of dependencies
    // to build and pass with the `--extern` flag.
    pub aux_crates: Vec<(String, String)>,
    // Environment settings to use for compiling
    pub rustc_env: Vec<(String, String)>,
    // Environment variables to unset prior to compiling.
    // Variables are unset before applying 'rustc_env'.
    pub unset_rustc_env: Vec<String>,
    // Environment settings to use during execution
    pub exec_env: Vec<(String, String)>,
    // Build documentation for all specified aux-builds as well
    pub build_aux_docs: bool,
    // Flag to force a crate to be built with the host architecture
    pub force_host: bool,
    // Check stdout for error-pattern output as well as stderr
    pub check_stdout: bool,
    // Check stdout & stderr for output of run-pass test
    pub check_run_results: bool,
    // For UI tests, allows compiler to generate arbitrary output to stdout
    pub dont_check_compiler_stdout: bool,
    // For UI tests, allows compiler to generate arbitrary output to stderr
    pub dont_check_compiler_stderr: bool,
    // Don't force a --crate-type=dylib flag on the command line
    //
    // Set this for example if you have an auxiliary test file that contains
    // a proc-macro and needs `#![crate_type = "proc-macro"]`. This ensures
    // that the aux file is compiled as a `proc-macro` and not as a `dylib`.
    pub no_prefer_dynamic: bool,
    // Run -Zunpretty expanded when running pretty printing tests
    pub pretty_expanded: bool,
    // Which pretty mode are we testing with, default to 'normal'
    pub pretty_mode: String,
    // Only compare pretty output and don't try compiling
    pub pretty_compare_only: bool,
    // Patterns which must not appear in the output of a cfail test.
    pub forbid_output: Vec<String>,
    // Revisions to test for incremental compilation.
    pub revisions: Vec<String>,
    // Directory (if any) to use for incremental compilation.  This is
    // not set by end-users; rather it is set by the incremental
    // testing harness and used when generating compilation
    // arguments. (In particular, it propagates to the aux-builds.)
    pub incremental_dir: Option<PathBuf>,
    // If `true`, this test will use incremental compilation.
    //
    // This can be set manually with the `incremental` header, or implicitly
    // by being a part of an incremental mode test. Using the `incremental`
    // header should be avoided if possible; using an incremental mode test is
    // preferred. Incremental mode tests support multiple passes, which can
    // verify that the incremental cache can be loaded properly after being
    // created. Just setting the header will only verify the behavior with
    // creating an incremental cache, but doesn't check that it is created
    // correctly.
    //
    // Compiletest will create the incremental directory, and ensure it is
    // empty before the test starts. Incremental mode tests will reuse the
    // incremental directory between passes in the same test.
    pub incremental: bool,
    // If `true`, this test is a known bug.
    //
    // When set, some requirements are relaxed. Currently, this only means no
    // error annotations are needed, but this may be updated in the future to
    // include other relaxations.
    pub known_bug: bool,
    // How far should the test proceed while still passing.
    pass_mode: Option<PassMode>,
    // Ignore `--pass` overrides from the command line for this test.
    ignore_pass: bool,
    // How far this test should proceed to start failing.
    pub fail_mode: Option<FailMode>,
    // rustdoc will test the output of the `--test` option
    pub check_test_line_numbers_match: bool,
    // customized normalization rules
    pub normalize_stdout: Vec<(String, String)>,
    pub normalize_stderr: Vec<(String, String)>,
    pub failure_status: i32,
    // Whether or not `rustfix` should apply the `CodeSuggestion`s of this test and compile the
    // resulting Rust code.
    pub run_rustfix: bool,
    // If true, `rustfix` will only apply `MachineApplicable` suggestions.
    pub rustfix_only_machine_applicable: bool,
    pub assembly_output: Option<String>,
    // If true, the test is expected to ICE
    pub should_ice: bool,
    // If true, the stderr is expected to be different across bit-widths.
    pub stderr_per_bitwidth: bool,
    // The MIR opt to unit test, if any
    pub mir_unit_test: Option<String>,
    // Whether to tell `rustc` to remap the "src base" directory to a fake
    // directory.
    pub remap_src_base: bool,
}

mod directives {
    pub const ERROR_PATTERN: &'static str = "error-pattern";
    pub const REGEX_ERROR_PATTERN: &'static str = "regex-error-pattern";
    pub const COMPILE_FLAGS: &'static str = "compile-flags";
    pub const RUN_FLAGS: &'static str = "run-flags";
    pub const SHOULD_ICE: &'static str = "should-ice";
    pub const BUILD_AUX_DOCS: &'static str = "build-aux-docs";
    pub const FORCE_HOST: &'static str = "force-host";
    pub const CHECK_STDOUT: &'static str = "check-stdout";
    pub const CHECK_RUN_RESULTS: &'static str = "check-run-results";
    pub const DONT_CHECK_COMPILER_STDOUT: &'static str = "dont-check-compiler-stdout";
    pub const DONT_CHECK_COMPILER_STDERR: &'static str = "dont-check-compiler-stderr";
    pub const NO_PREFER_DYNAMIC: &'static str = "no-prefer-dynamic";
    pub const PRETTY_EXPANDED: &'static str = "pretty-expanded";
    pub const PRETTY_MODE: &'static str = "pretty-mode";
    pub const PRETTY_COMPARE_ONLY: &'static str = "pretty-compare-only";
    pub const AUX_BUILD: &'static str = "aux-build";
    pub const AUX_CRATE: &'static str = "aux-crate";
    pub const EXEC_ENV: &'static str = "exec-env";
    pub const RUSTC_ENV: &'static str = "rustc-env";
    pub const UNSET_RUSTC_ENV: &'static str = "unset-rustc-env";
    pub const FORBID_OUTPUT: &'static str = "forbid-output";
    pub const CHECK_TEST_LINE_NUMBERS_MATCH: &'static str = "check-test-line-numbers-match";
    pub const IGNORE_PASS: &'static str = "ignore-pass";
    pub const FAILURE_STATUS: &'static str = "failure-status";
    pub const RUN_RUSTFIX: &'static str = "run-rustfix";
    pub const RUSTFIX_ONLY_MACHINE_APPLICABLE: &'static str = "rustfix-only-machine-applicable";
    pub const ASSEMBLY_OUTPUT: &'static str = "assembly-output";
    pub const STDERR_PER_BITWIDTH: &'static str = "stderr-per-bitwidth";
    pub const INCREMENTAL: &'static str = "incremental";
    pub const KNOWN_BUG: &'static str = "known-bug";
    pub const MIR_UNIT_TEST: &'static str = "unit-test";
    pub const REMAP_SRC_BASE: &'static str = "remap-src-base";
    // This isn't a real directive, just one that is probably mistyped often
    pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
}

impl TestProps {
    pub fn new() -> Self {
        TestProps {
            error_patterns: vec![],
            regex_error_patterns: vec![],
            compile_flags: vec![],
            run_flags: None,
            pp_exact: None,
            aux_builds: vec![],
            aux_crates: vec![],
            revisions: vec![],
            rustc_env: vec![],
            unset_rustc_env: vec![],
            exec_env: vec![],
            build_aux_docs: false,
            force_host: false,
            check_stdout: false,
            check_run_results: false,
            dont_check_compiler_stdout: false,
            dont_check_compiler_stderr: false,
            no_prefer_dynamic: false,
            pretty_expanded: false,
            pretty_mode: "normal".to_string(),
            pretty_compare_only: false,
            forbid_output: vec![],
            incremental_dir: None,
            incremental: false,
            known_bug: false,
            pass_mode: None,
            fail_mode: None,
            ignore_pass: false,
            check_test_line_numbers_match: false,
            normalize_stdout: vec![],
            normalize_stderr: vec![],
            failure_status: -1,
            run_rustfix: false,
            rustfix_only_machine_applicable: false,
            assembly_output: None,
            should_ice: false,
            stderr_per_bitwidth: false,
            mir_unit_test: None,
            remap_src_base: false,
        }
    }

    pub fn from_aux_file(&self, testfile: &Path, cfg: Option<&str>, config: &Config) -> Self {
        let mut props = TestProps::new();

        // copy over select properties to the aux build:
        props.incremental_dir = self.incremental_dir.clone();
        props.ignore_pass = true;
        props.load_from(testfile, cfg, config);

        props
    }

    pub fn from_file(testfile: &Path, cfg: Option<&str>, config: &Config) -> Self {
        let mut props = TestProps::new();
        props.load_from(testfile, cfg, config);

        match (props.pass_mode, props.fail_mode) {
            (None, None) if config.mode == Mode::Ui => props.fail_mode = Some(FailMode::Check),
            (Some(_), Some(_)) => panic!("cannot use a *-fail and *-pass mode together"),
            _ => {}
        }

        props
    }

    /// Loads properties from `testfile` into `props`. If a property is
    /// tied to a particular revision `foo` (indicated by writing
    /// `//[foo]`), then the property is ignored unless `cfg` is
    /// `Some("foo")`.
    fn load_from(&mut self, testfile: &Path, cfg: Option<&str>, config: &Config) {
        // Mode-dependent defaults.
        self.remap_src_base = config.mode == Mode::Ui && !config.suite.contains("rustdoc");

        let mut has_edition = false;
        if !testfile.is_dir() {
            let file = File::open(testfile).unwrap();

            iter_header(testfile, file, &mut |revision, ln| {
                if revision.is_some() && revision != cfg {
                    return;
                }

                use directives::*;

                config.push_name_value_directive(
                    ln,
                    ERROR_PATTERN,
                    &mut self.error_patterns,
                    |r| r,
                );
                config.push_name_value_directive(
                    ln,
                    REGEX_ERROR_PATTERN,
                    &mut self.regex_error_patterns,
                    |r| r,
                );

                if let Some(flags) = config.parse_name_value_directive(ln, COMPILE_FLAGS) {
                    self.compile_flags.extend(flags.split_whitespace().map(|s| s.to_owned()));
                }
                if config.parse_name_value_directive(ln, INCORRECT_COMPILER_FLAGS).is_some() {
                    panic!("`compiler-flags` directive should be spelled `compile-flags`");
                }

                if let Some(edition) = config.parse_edition(ln) {
                    self.compile_flags.push(format!("--edition={}", edition.trim()));
                    has_edition = true;
                }

                config.parse_and_update_revisions(ln, &mut self.revisions);

                config.set_name_value_directive(ln, RUN_FLAGS, &mut self.run_flags, |r| r);

                if self.pp_exact.is_none() {
                    self.pp_exact = config.parse_pp_exact(ln, testfile);
                }

                config.set_name_directive(ln, SHOULD_ICE, &mut self.should_ice);
                config.set_name_directive(ln, BUILD_AUX_DOCS, &mut self.build_aux_docs);
                config.set_name_directive(ln, FORCE_HOST, &mut self.force_host);
                config.set_name_directive(ln, CHECK_STDOUT, &mut self.check_stdout);
                config.set_name_directive(ln, CHECK_RUN_RESULTS, &mut self.check_run_results);
                config.set_name_directive(
                    ln,
                    DONT_CHECK_COMPILER_STDOUT,
                    &mut self.dont_check_compiler_stdout,
                );
                config.set_name_directive(
                    ln,
                    DONT_CHECK_COMPILER_STDERR,
                    &mut self.dont_check_compiler_stderr,
                );
                config.set_name_directive(ln, NO_PREFER_DYNAMIC, &mut self.no_prefer_dynamic);
                config.set_name_directive(ln, PRETTY_EXPANDED, &mut self.pretty_expanded);

                if let Some(m) = config.parse_name_value_directive(ln, PRETTY_MODE) {
                    self.pretty_mode = m;
                }

                config.set_name_directive(ln, PRETTY_COMPARE_ONLY, &mut self.pretty_compare_only);
                config.push_name_value_directive(ln, AUX_BUILD, &mut self.aux_builds, |r| {
                    r.trim().to_string()
                });
                config.push_name_value_directive(
                    ln,
                    AUX_CRATE,
                    &mut self.aux_crates,
                    Config::parse_aux_crate,
                );
                config.push_name_value_directive(
                    ln,
                    EXEC_ENV,
                    &mut self.exec_env,
                    Config::parse_env,
                );
                config.push_name_value_directive(
                    ln,
                    RUSTC_ENV,
                    &mut self.rustc_env,
                    Config::parse_env,
                );
                config.push_name_value_directive(
                    ln,
                    UNSET_RUSTC_ENV,
                    &mut self.unset_rustc_env,
                    |r| r,
                );
                config.push_name_value_directive(ln, FORBID_OUTPUT, &mut self.forbid_output, |r| r);
                config.set_name_directive(
                    ln,
                    CHECK_TEST_LINE_NUMBERS_MATCH,
                    &mut self.check_test_line_numbers_match,
                );

                self.update_pass_mode(ln, cfg, config);
                self.update_fail_mode(ln, config);

                config.set_name_directive(ln, IGNORE_PASS, &mut self.ignore_pass);

                if let Some(rule) = config.parse_custom_normalization(ln, "normalize-stdout") {
                    self.normalize_stdout.push(rule);
                }
                if let Some(rule) = config.parse_custom_normalization(ln, "normalize-stderr") {
                    self.normalize_stderr.push(rule);
                }

                if let Some(code) = config
                    .parse_name_value_directive(ln, FAILURE_STATUS)
                    .and_then(|code| code.trim().parse::<i32>().ok())
                {
                    self.failure_status = code;
                }

                config.set_name_directive(ln, RUN_RUSTFIX, &mut self.run_rustfix);
                config.set_name_directive(
                    ln,
                    RUSTFIX_ONLY_MACHINE_APPLICABLE,
                    &mut self.rustfix_only_machine_applicable,
                );
                config.set_name_value_directive(
                    ln,
                    ASSEMBLY_OUTPUT,
                    &mut self.assembly_output,
                    |r| r.trim().to_string(),
                );
                config.set_name_directive(ln, STDERR_PER_BITWIDTH, &mut self.stderr_per_bitwidth);
                config.set_name_directive(ln, INCREMENTAL, &mut self.incremental);

                // Unlike the other `name_value_directive`s this needs to be handled manually,
                // because it sets a `bool` flag.
                if let Some(known_bug) = config.parse_name_value_directive(ln, KNOWN_BUG) {
                    let known_bug = known_bug.trim();
                    if known_bug == "unknown"
                        || known_bug.split(',').all(|issue_ref| {
                            issue_ref
                                .trim()
                                .split_once('#')
                                .filter(|(_, number)| {
                                    number.chars().all(|digit| digit.is_numeric())
                                })
                                .is_some()
                        })
                    {
                        self.known_bug = true;
                    } else {
                        panic!(
                            "Invalid known-bug value: {known_bug}\nIt requires comma-separated issue references (`#000` or `chalk#000`) or `known-bug: unknown`."
                        );
                    }
                } else if config.parse_name_directive(ln, KNOWN_BUG) {
                    panic!(
                        "Invalid known-bug attribute, requires comma-separated issue references (`#000` or `chalk#000`) or `known-bug: unknown`."
                    );
                }

                config.set_name_value_directive(ln, MIR_UNIT_TEST, &mut self.mir_unit_test, |s| {
                    s.trim().to_string()
                });
                config.set_name_directive(ln, REMAP_SRC_BASE, &mut self.remap_src_base);
            });
        }

        if self.failure_status == -1 {
            self.failure_status = 1;
        }
        if self.should_ice {
            self.failure_status = 101;
        }

        if config.mode == Mode::Incremental {
            self.incremental = true;
        }

        for key in &["RUST_TEST_NOCAPTURE", "RUST_TEST_THREADS"] {
            if let Ok(val) = env::var(key) {
                if self.exec_env.iter().find(|&&(ref x, _)| x == key).is_none() {
                    self.exec_env.push(((*key).to_owned(), val))
                }
            }
        }

        if let (Some(edition), false) = (&config.edition, has_edition) {
            self.compile_flags.push(format!("--edition={}", edition));
        }
    }

    fn update_fail_mode(&mut self, ln: &str, config: &Config) {
        let check_ui = |mode: &str| {
            if config.mode != Mode::Ui {
                panic!("`{}-fail` header is only supported in UI tests", mode);
            }
        };
        if config.mode == Mode::Ui && config.parse_name_directive(ln, "compile-fail") {
            panic!("`compile-fail` header is useless in UI tests");
        }
        let fail_mode = if config.parse_name_directive(ln, "check-fail") {
            check_ui("check");
            Some(FailMode::Check)
        } else if config.parse_name_directive(ln, "build-fail") {
            check_ui("build");
            Some(FailMode::Build)
        } else if config.parse_name_directive(ln, "run-fail") {
            check_ui("run");
            Some(FailMode::Run)
        } else {
            None
        };
        match (self.fail_mode, fail_mode) {
            (None, Some(_)) => self.fail_mode = fail_mode,
            (Some(_), Some(_)) => panic!("multiple `*-fail` headers in a single test"),
            (_, None) => {}
        }
    }

    fn update_pass_mode(&mut self, ln: &str, revision: Option<&str>, config: &Config) {
        let check_no_run = |s| {
            if config.mode != Mode::Ui && config.mode != Mode::Incremental {
                panic!("`{}` header is only supported in UI and incremental tests", s);
            }
            if config.mode == Mode::Incremental
                && !revision.map_or(false, |r| r.starts_with("cfail"))
                && !self.revisions.iter().all(|r| r.starts_with("cfail"))
            {
                panic!("`{}` header is only supported in `cfail` incremental tests", s);
            }
        };
        let pass_mode = if config.parse_name_directive(ln, "check-pass") {
            check_no_run("check-pass");
            Some(PassMode::Check)
        } else if config.parse_name_directive(ln, "build-pass") {
            check_no_run("build-pass");
            Some(PassMode::Build)
        } else if config.parse_name_directive(ln, "run-pass") {
            if config.mode != Mode::Ui {
                panic!("`run-pass` header is only supported in UI tests")
            }
            Some(PassMode::Run)
        } else {
            None
        };
        match (self.pass_mode, pass_mode) {
            (None, Some(_)) => self.pass_mode = pass_mode,
            (Some(_), Some(_)) => panic!("multiple `*-pass` headers in a single test"),
            (_, None) => {}
        }
    }

    pub fn pass_mode(&self, config: &Config) -> Option<PassMode> {
        if !self.ignore_pass && self.fail_mode.is_none() {
            if let mode @ Some(_) = config.force_pass_mode {
                return mode;
            }
        }
        self.pass_mode
    }

    // does not consider CLI override for pass mode
    pub fn local_pass_mode(&self) -> Option<PassMode> {
        self.pass_mode
    }
}

pub fn line_directive<'line>(
    comment: &str,
    ln: &'line str,
) -> Option<(Option<&'line str>, &'line str)> {
    if ln.starts_with(comment) {
        let ln = ln[comment.len()..].trim_start();
        if ln.starts_with('[') {
            // A comment like `//[foo]` is specific to revision `foo`
            if let Some(close_brace) = ln.find(']') {
                let lncfg = &ln[1..close_brace];

                Some((Some(lncfg), ln[(close_brace + 1)..].trim_start()))
            } else {
                panic!("malformed condition directive: expected `{}[foo]`, found `{}`", comment, ln)
            }
        } else {
            Some((None, ln))
        }
    } else {
        None
    }
}

fn iter_header<R: Read>(testfile: &Path, rdr: R, it: &mut dyn FnMut(Option<&str>, &str)) {
    if testfile.is_dir() {
        return;
    }

    let comment = if testfile.extension().map(|e| e == "rs") == Some(true) { "//" } else { "#" };

    let mut rdr = BufReader::new(rdr);
    let mut ln = String::new();

    loop {
        ln.clear();
        if rdr.read_line(&mut ln).unwrap() == 0 {
            break;
        }

        // Assume that any directives will be found before the first
        // module or function. This doesn't seem to be an optimization
        // with a warm page cache. Maybe with a cold one.
        let ln = ln.trim();
        if ln.starts_with("fn") || ln.starts_with("mod") {
            return;
        } else if let Some((lncfg, ln)) = line_directive(comment, ln) {
            it(lncfg, ln);
        }
    }
}

impl Config {
    fn parse_aux_crate(r: String) -> (String, String) {
        let mut parts = r.trim().splitn(2, '=');
        (
            parts.next().expect("missing aux-crate name (e.g. log=log.rs)").to_string(),
            parts.next().expect("missing aux-crate value (e.g. log=log.rs)").to_string(),
        )
    }

    fn parse_and_update_revisions(&self, line: &str, existing: &mut Vec<String>) {
        if let Some(raw) = self.parse_name_value_directive(line, "revisions") {
            let mut duplicates: HashSet<_> = existing.iter().cloned().collect();
            for revision in raw.split_whitespace().map(|r| r.to_string()) {
                if !duplicates.insert(revision.clone()) {
                    panic!("Duplicate revision: `{}` in line `{}`", revision, raw);
                }
                existing.push(revision);
            }
        }
    }

    fn parse_env(nv: String) -> (String, String) {
        // nv is either FOO or FOO=BAR
        let mut strs: Vec<String> = nv.splitn(2, '=').map(str::to_owned).collect();

        match strs.len() {
            1 => (strs.pop().unwrap(), String::new()),
            2 => {
                let end = strs.pop().unwrap();
                (strs.pop().unwrap(), end)
            }
            n => panic!("Expected 1 or 2 strings, not {}", n),
        }
    }

    fn parse_pp_exact(&self, line: &str, testfile: &Path) -> Option<PathBuf> {
        if let Some(s) = self.parse_name_value_directive(line, "pp-exact") {
            Some(PathBuf::from(&s))
        } else if self.parse_name_directive(line, "pp-exact") {
            testfile.file_name().map(PathBuf::from)
        } else {
            None
        }
    }

    fn parse_custom_normalization(&self, mut line: &str, prefix: &str) -> Option<(String, String)> {
        if self.parse_cfg_name_directive(line, prefix) == ParsedNameDirective::Match {
            let from = parse_normalization_string(&mut line)?;
            let to = parse_normalization_string(&mut line)?;
            Some((from, to))
        } else {
            None
        }
    }

    fn parse_needs_matching_clang(&self, line: &str) -> bool {
        self.parse_name_directive(line, "needs-matching-clang")
    }

    fn parse_needs_profiler_support(&self, line: &str) -> bool {
        self.parse_name_directive(line, "needs-profiler-support")
    }

    /// Parses a name-value directive which contains config-specific information, e.g., `ignore-x86`
    /// or `normalize-stderr-32bit`.
    fn parse_cfg_name_directive(&self, line: &str, prefix: &str) -> ParsedNameDirective {
        if !line.as_bytes().starts_with(prefix.as_bytes()) {
            return ParsedNameDirective::NoMatch;
        }
        if line.as_bytes().get(prefix.len()) != Some(&b'-') {
            return ParsedNameDirective::NoMatch;
        }

        let name = line[prefix.len() + 1..].split(&[':', ' '][..]).next().unwrap();

        let matches_pointer_width = || {
            name.strip_suffix("bit")
                .and_then(|width| width.parse::<u32>().ok())
                .map(|width| self.get_pointer_width() == width)
                .unwrap_or(false)
        };

        // If something is ignored for emscripten, it likely also needs to be
        // ignored for wasm32-unknown-unknown.
        // `wasm32-bare` is an alias to refer to just wasm32-unknown-unknown
        // (in contrast to `wasm32` which also matches non-bare targets like
        // asmjs-unknown-emscripten).
        let matches_wasm32_alias = || {
            self.target == "wasm32-unknown-unknown" && matches!(name, "emscripten" | "wasm32-bare")
        };

        let is_match = name == "test" ||
            self.target == name ||                              // triple
            self.matches_os(name) ||
            self.matches_env(name) ||
            self.matches_abi(name) ||
            self.matches_family(name) ||
            self.target.ends_with(name) ||                      // target and env
            self.matches_arch(name) ||
            matches_wasm32_alias() ||
            matches_pointer_width() ||
            name == self.stage_id.split('-').next().unwrap() || // stage
            name == self.channel ||                             // channel
            (self.target != self.host && name == "cross-compile") ||
            (name == "endian-big" && self.is_big_endian()) ||
            (self.remote_test_client.is_some() && name == "remote") ||
            match self.compare_mode {
                Some(CompareMode::Polonius) => name == "compare-mode-polonius",
                Some(CompareMode::Chalk) => name == "compare-mode-chalk",
                Some(CompareMode::NextSolver) => name == "compare-mode-next-solver",
                Some(CompareMode::SplitDwarf) => name == "compare-mode-split-dwarf",
                Some(CompareMode::SplitDwarfSingle) => name == "compare-mode-split-dwarf-single",
                None => false,
            } ||
            (cfg!(debug_assertions) && name == "debug") ||
            match self.debugger {
                Some(Debugger::Cdb) => name == "cdb",
                Some(Debugger::Gdb) => name == "gdb",
                Some(Debugger::Lldb) => name == "lldb",
                None => false,
            };

        if is_match { ParsedNameDirective::Match } else { ParsedNameDirective::NoMatch }
    }

    fn has_cfg_prefix(&self, line: &str, prefix: &str) -> bool {
        // returns whether this line contains this prefix or not. For prefix
        // "ignore", returns true if line says "ignore-x86_64", "ignore-arch",
        // "ignore-android" etc.
        line.starts_with(prefix) && line.as_bytes().get(prefix.len()) == Some(&b'-')
    }

    fn parse_name_directive(&self, line: &str, directive: &str) -> bool {
        // Ensure the directive is a whole word. Do not match "ignore-x86" when
        // the line says "ignore-x86_64".
        line.starts_with(directive)
            && matches!(line.as_bytes().get(directive.len()), None | Some(&b' ') | Some(&b':'))
    }

    fn parse_negative_name_directive(&self, line: &str, directive: &str) -> bool {
        line.starts_with("no-") && self.parse_name_directive(&line[3..], directive)
    }

    pub fn parse_name_value_directive(&self, line: &str, directive: &str) -> Option<String> {
        let colon = directive.len();
        if line.starts_with(directive) && line.as_bytes().get(colon) == Some(&b':') {
            let value = line[(colon + 1)..].to_owned();
            debug!("{}: {}", directive, value);
            Some(expand_variables(value, self))
        } else {
            None
        }
    }

    pub fn find_rust_src_root(&self) -> Option<PathBuf> {
        let mut path = self.src_base.clone();
        let path_postfix = Path::new("src/etc/lldb_batchmode.py");

        while path.pop() {
            if path.join(&path_postfix).is_file() {
                return Some(path);
            }
        }

        None
    }

    fn parse_edition(&self, line: &str) -> Option<String> {
        self.parse_name_value_directive(line, "edition")
    }

    fn set_name_directive(&self, line: &str, directive: &str, value: &mut bool) {
        match value {
            true => {
                if self.parse_negative_name_directive(line, directive) {
                    *value = false;
                }
            }
            false => {
                if self.parse_name_directive(line, directive) {
                    *value = true;
                }
            }
        }
    }

    fn set_name_value_directive<T>(
        &self,
        line: &str,
        directive: &str,
        value: &mut Option<T>,
        parse: impl FnOnce(String) -> T,
    ) {
        if value.is_none() {
            *value = self.parse_name_value_directive(line, directive).map(parse);
        }
    }

    fn push_name_value_directive<T>(
        &self,
        line: &str,
        directive: &str,
        values: &mut Vec<T>,
        parse: impl FnOnce(String) -> T,
    ) {
        if let Some(value) = self.parse_name_value_directive(line, directive).map(parse) {
            values.push(value);
        }
    }
}

fn expand_variables(mut value: String, config: &Config) -> String {
    const CWD: &str = "{{cwd}}";
    const SRC_BASE: &str = "{{src-base}}";
    const BUILD_BASE: &str = "{{build-base}}";

    if value.contains(CWD) {
        let cwd = env::current_dir().unwrap();
        value = value.replace(CWD, &cwd.to_string_lossy());
    }

    if value.contains(SRC_BASE) {
        value = value.replace(SRC_BASE, &config.src_base.to_string_lossy());
    }

    if value.contains(BUILD_BASE) {
        value = value.replace(BUILD_BASE, &config.build_base.to_string_lossy());
    }

    value
}

/// Finds the next quoted string `"..."` in `line`, and extract the content from it. Move the `line`
/// variable after the end of the quoted string.
///
/// # Examples
///
/// ```
/// let mut s = "normalize-stderr-32bit: \"something (32 bits)\" -> \"something ($WORD bits)\".";
/// let first = parse_normalization_string(&mut s);
/// assert_eq!(first, Some("something (32 bits)".to_owned()));
/// assert_eq!(s, " -> \"something ($WORD bits)\".");
/// ```
fn parse_normalization_string(line: &mut &str) -> Option<String> {
    // FIXME support escapes in strings.
    let begin = line.find('"')? + 1;
    let end = line[begin..].find('"')? + begin;
    let result = line[begin..end].to_owned();
    *line = &line[end + 1..];
    Some(result)
}

pub fn extract_llvm_version(version: &str) -> Option<u32> {
    let pat = |c: char| !c.is_ascii_digit() && c != '.';
    let version_without_suffix = match version.find(pat) {
        Some(pos) => &version[..pos],
        None => version,
    };
    let components: Vec<u32> = version_without_suffix
        .split('.')
        .map(|s| s.parse().expect("Malformed version component"))
        .collect();
    let version = match *components {
        [a] => a * 10_000,
        [a, b] => a * 10_000 + b * 100,
        [a, b, c] => a * 10_000 + b * 100 + c,
        _ => panic!("Malformed version"),
    };
    Some(version)
}

pub fn extract_llvm_version_from_binary(binary_path: &str) -> Option<u32> {
    let output = Command::new(binary_path).arg("--version").output().ok()?;
    if !output.status.success() {
        return None;
    }
    let version = String::from_utf8(output.stdout).ok()?;
    for line in version.lines() {
        if let Some(version) = line.split("LLVM version ").skip(1).next() {
            return extract_llvm_version(version);
        }
    }
    None
}

/// Takes a directive of the form "<version1> [- <version2>]",
/// returns the numeric representation of <version1> and <version2> as
/// tuple: (<version1> as u32, <version2> as u32)
///
/// If the <version2> part is omitted, the second component of the tuple
/// is the same as <version1>.
fn extract_version_range<F>(line: &str, parse: F) -> Option<(u32, u32)>
where
    F: Fn(&str) -> Option<u32>,
{
    let mut splits = line.splitn(2, "- ").map(str::trim);
    let min = splits.next().unwrap();
    if min.ends_with('-') {
        return None;
    }

    let max = splits.next();

    if min.is_empty() {
        return None;
    }

    let min = parse(min)?;
    let max = match max {
        Some(max) if max.is_empty() => return None,
        Some(max) => parse(max)?,
        _ => min,
    };

    Some((min, max))
}

pub fn make_test_description<R: Read>(
    config: &Config,
    name: test::TestName,
    path: &Path,
    src: R,
    cfg: Option<&str>,
) -> test::TestDesc {
    let mut ignore = false;
    let mut ignore_message = None;
    let mut should_fail = false;

    let rustc_has_profiler_support = env::var_os("RUSTC_PROFILER_SUPPORT").is_some();
    let rustc_has_sanitizer_support = env::var_os("RUSTC_SANITIZER_SUPPORT").is_some();
    let has_asm_support = config.has_asm_support();
    let has_asan = util::ASAN_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_cfi = util::CFI_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_kcfi = util::KCFI_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_kasan = util::KASAN_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_lsan = util::LSAN_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_msan = util::MSAN_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_tsan = util::TSAN_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_hwasan = util::HWASAN_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_memtag = util::MEMTAG_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_shadow_call_stack = util::SHADOWCALLSTACK_SUPPORTED_TARGETS.contains(&&*config.target);
    let has_xray = util::XRAY_SUPPORTED_TARGETS.contains(&&*config.target);

    // For tests using the `needs-rust-lld` directive (e.g. for `-Zgcc-ld=lld`), we need to find
    // whether `rust-lld` is present in the compiler under test.
    //
    // The --compile-lib-path is the path to host shared libraries, but depends on the OS. For
    // example:
    // - on linux, it can be <sysroot>/lib
    // - on windows, it can be <sysroot>/bin
    //
    // However, `rust-lld` is only located under the lib path, so we look for it there.
    let has_rust_lld = config
        .compile_lib_path
        .parent()
        .expect("couldn't traverse to the parent of the specified --compile-lib-path")
        .join("lib")
        .join("rustlib")
        .join(&config.target)
        .join("bin")
        .join(if config.host.contains("windows") { "rust-lld.exe" } else { "rust-lld" })
        .exists();

    iter_header(path, src, &mut |revision, ln| {
        if revision.is_some() && revision != cfg {
            return;
        }
        macro_rules! reason {
            ($e:expr) => {
                ignore |= match $e {
                    true => {
                        ignore_message = Some(stringify!($e));
                        true
                    }
                    false => ignore,
                }
            };
        }
        ignore = match config.parse_cfg_name_directive(ln, "ignore") {
            ParsedNameDirective::Match => {
                ignore_message = Some("cfg -> ignore => Match");
                true
            }
            ParsedNameDirective::NoMatch => ignore,
        };

        if config.has_cfg_prefix(ln, "only") {
            ignore = match config.parse_cfg_name_directive(ln, "only") {
                ParsedNameDirective::Match => ignore,
                ParsedNameDirective::NoMatch => {
                    ignore_message = Some("cfg -> only => NoMatch");
                    true
                }
            };
        }

        reason!(ignore_llvm(config, ln));
        reason!(
            config.run_clang_based_tests_with.is_none() && config.parse_needs_matching_clang(ln)
        );
        reason!(!has_asm_support && config.parse_name_directive(ln, "needs-asm-support"));
        reason!(!rustc_has_profiler_support && config.parse_needs_profiler_support(ln));
        reason!(!config.run_enabled() && config.parse_name_directive(ln, "needs-run-enabled"));
        reason!(
            !rustc_has_sanitizer_support
                && config.parse_name_directive(ln, "needs-sanitizer-support")
        );
        reason!(!has_asan && config.parse_name_directive(ln, "needs-sanitizer-address"));
        reason!(!has_cfi && config.parse_name_directive(ln, "needs-sanitizer-cfi"));
        reason!(!has_kcfi && config.parse_name_directive(ln, "needs-sanitizer-kcfi"));
        reason!(!has_kasan && config.parse_name_directive(ln, "needs-sanitizer-kasan"));
        reason!(!has_lsan && config.parse_name_directive(ln, "needs-sanitizer-leak"));
        reason!(!has_msan && config.parse_name_directive(ln, "needs-sanitizer-memory"));
        reason!(!has_tsan && config.parse_name_directive(ln, "needs-sanitizer-thread"));
        reason!(!has_hwasan && config.parse_name_directive(ln, "needs-sanitizer-hwaddress"));
        reason!(!has_memtag && config.parse_name_directive(ln, "needs-sanitizer-memtag"));
        reason!(
            !has_shadow_call_stack
                && config.parse_name_directive(ln, "needs-sanitizer-shadow-call-stack")
        );
        reason!(!config.can_unwind() && config.parse_name_directive(ln, "needs-unwind"));
        reason!(!has_xray && config.parse_name_directive(ln, "needs-xray"));
        reason!(
            config.target == "wasm32-unknown-unknown"
                && config.parse_name_directive(ln, directives::CHECK_RUN_RESULTS)
        );
        reason!(config.debugger == Some(Debugger::Cdb) && ignore_cdb(config, ln));
        reason!(config.debugger == Some(Debugger::Gdb) && ignore_gdb(config, ln));
        reason!(config.debugger == Some(Debugger::Lldb) && ignore_lldb(config, ln));
        reason!(!has_rust_lld && config.parse_name_directive(ln, "needs-rust-lld"));
        should_fail |= config.parse_name_directive(ln, "should-fail");
    });

    // The `should-fail` annotation doesn't apply to pretty tests,
    // since we run the pretty printer across all tests by default.
    // If desired, we could add a `should-fail-pretty` annotation.
    let should_panic = match config.mode {
        crate::common::Pretty => test::ShouldPanic::No,
        _ if should_fail => test::ShouldPanic::Yes,
        _ => test::ShouldPanic::No,
    };

    test::TestDesc {
        name,
        ignore,
        ignore_message,
        should_panic,
        compile_fail: false,
        no_run: false,
        test_type: test::TestType::Unknown,
    }
}

fn ignore_cdb(config: &Config, line: &str) -> bool {
    if let Some(actual_version) = config.cdb_version {
        if let Some(min_version) = line.strip_prefix("min-cdb-version:").map(str::trim) {
            let min_version = extract_cdb_version(min_version).unwrap_or_else(|| {
                panic!("couldn't parse version range: {:?}", min_version);
            });

            // Ignore if actual version is smaller than the minimum
            // required version
            return actual_version < min_version;
        }
    }
    false
}

fn ignore_gdb(config: &Config, line: &str) -> bool {
    if let Some(actual_version) = config.gdb_version {
        if let Some(rest) = line.strip_prefix("min-gdb-version:").map(str::trim) {
            let (start_ver, end_ver) = extract_version_range(rest, extract_gdb_version)
                .unwrap_or_else(|| {
                    panic!("couldn't parse version range: {:?}", rest);
                });

            if start_ver != end_ver {
                panic!("Expected single GDB version")
            }
            // Ignore if actual version is smaller than the minimum
            // required version
            return actual_version < start_ver;
        } else if let Some(rest) = line.strip_prefix("ignore-gdb-version:").map(str::trim) {
            let (min_version, max_version) = extract_version_range(rest, extract_gdb_version)
                .unwrap_or_else(|| {
                    panic!("couldn't parse version range: {:?}", rest);
                });

            if max_version < min_version {
                panic!("Malformed GDB version range: max < min")
            }

            return actual_version >= min_version && actual_version <= max_version;
        }
    }
    false
}

fn ignore_lldb(config: &Config, line: &str) -> bool {
    if let Some(actual_version) = config.lldb_version {
        if let Some(min_version) = line.strip_prefix("min-lldb-version:").map(str::trim) {
            let min_version = min_version.parse().unwrap_or_else(|e| {
                panic!("Unexpected format of LLDB version string: {}\n{:?}", min_version, e);
            });
            // Ignore if actual version is smaller the minimum required
            // version
            actual_version < min_version
        } else {
            line.starts_with("rust-lldb") && !config.lldb_native_rust
        }
    } else {
        false
    }
}

fn ignore_llvm(config: &Config, line: &str) -> bool {
    if config.system_llvm && line.starts_with("no-system-llvm") {
        return true;
    }
    if let Some(needed_components) =
        config.parse_name_value_directive(line, "needs-llvm-components")
    {
        let components: HashSet<_> = config.llvm_components.split_whitespace().collect();
        if let Some(missing_component) = needed_components
            .split_whitespace()
            .find(|needed_component| !components.contains(needed_component))
        {
            if env::var_os("COMPILETEST_NEEDS_ALL_LLVM_COMPONENTS").is_some() {
                panic!("missing LLVM component: {}", missing_component);
            }
            return true;
        }
    }
    if let Some(actual_version) = config.llvm_version {
        if let Some(rest) = line.strip_prefix("min-llvm-version:").map(str::trim) {
            let min_version = extract_llvm_version(rest).unwrap();
            // Ignore if actual version is smaller the minimum required
            // version
            actual_version < min_version
        } else if let Some(rest) = line.strip_prefix("min-system-llvm-version:").map(str::trim) {
            let min_version = extract_llvm_version(rest).unwrap();
            // Ignore if using system LLVM and actual version
            // is smaller the minimum required version
            config.system_llvm && actual_version < min_version
        } else if let Some(rest) = line.strip_prefix("ignore-llvm-version:").map(str::trim) {
            // Syntax is: "ignore-llvm-version: <version1> [- <version2>]"
            let (v_min, v_max) =
                extract_version_range(rest, extract_llvm_version).unwrap_or_else(|| {
                    panic!("couldn't parse version range: {:?}", rest);
                });
            if v_max < v_min {
                panic!("Malformed LLVM version range: max < min")
            }
            // Ignore if version lies inside of range.
            actual_version >= v_min && actual_version <= v_max
        } else {
            false
        }
    } else {
        false
    }
}