1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
//! Code for building the standard library.

use crate::core::compiler::unit_dependencies::IsArtifact;
use crate::core::compiler::UnitInterner;
use crate::core::compiler::{CompileKind, CompileMode, RustcTargetData, Unit};
use crate::core::profiles::{Profiles, UnitFor};
use crate::core::resolver::features::{CliFeatures, FeaturesFor, ResolvedFeatures};
use crate::core::resolver::HasDevUnits;
use crate::core::{Dependency, PackageId, PackageSet, Resolve, SourceId, Workspace};
use crate::ops::{self, Packages};
use crate::util::errors::CargoResult;
use crate::Config;
use std::collections::{HashMap, HashSet};
use std::path::PathBuf;

use super::BuildConfig;

/// Parse the `-Zbuild-std` flag.
pub fn parse_unstable_flag(value: Option<&str>) -> Vec<String> {
    // This is a temporary hack until there is a more principled way to
    // declare dependencies in Cargo.toml.
    let value = value.unwrap_or("std");
    let mut crates: HashSet<&str> = value.split(',').collect();
    if crates.contains("std") {
        crates.insert("core");
        crates.insert("alloc");
        crates.insert("proc_macro");
        crates.insert("panic_unwind");
        crates.insert("compiler_builtins");
    } else if crates.contains("core") {
        crates.insert("compiler_builtins");
    }
    crates.into_iter().map(|s| s.to_string()).collect()
}

pub(crate) fn std_crates(config: &Config, units: Option<&[Unit]>) -> Option<Vec<String>> {
    let crates = config.cli_unstable().build_std.as_ref()?.clone();

    // Only build libtest if it looks like it is needed.
    let mut crates = crates.clone();
    // If we know what units we're building, we can filter for libtest depending on the jobs.
    if let Some(units) = units {
        if units
            .iter()
            .any(|unit| unit.mode.is_rustc_test() && unit.target.harness())
        {
            // Only build libtest when libstd is built (libtest depends on libstd)
            if crates.iter().any(|c| c == "std") && !crates.iter().any(|c| c == "test") {
                crates.push("test".to_string());
            }
        }
    } else {
        // We don't know what jobs are going to be run, so download libtest just in case.
        if !crates.iter().any(|c| c == "test") {
            crates.push("test".to_string())
        }
    }

    Some(crates)
}

/// Resolve the standard library dependencies.
pub fn resolve_std<'cfg>(
    ws: &Workspace<'cfg>,
    target_data: &mut RustcTargetData<'cfg>,
    build_config: &BuildConfig,
    crates: &[String],
) -> CargoResult<(PackageSet<'cfg>, Resolve, ResolvedFeatures)> {
    if build_config.build_plan {
        ws.config()
            .shell()
            .warn("-Zbuild-std does not currently fully support --build-plan")?;
    }

    let src_path = detect_sysroot_src_path(target_data)?;
    let to_patch = [
        "rustc-std-workspace-core",
        "rustc-std-workspace-alloc",
        "rustc-std-workspace-std",
    ];
    let patches = to_patch
        .iter()
        .map(|&name| {
            let source_path = SourceId::for_path(&src_path.join("library").join(name))?;
            let dep = Dependency::parse(name, None, source_path)?;
            Ok(dep)
        })
        .collect::<CargoResult<Vec<_>>>()?;
    let crates_io_url = crate::sources::CRATES_IO_INDEX.parse().unwrap();
    let patch = HashMap::from([(crates_io_url, patches)]);
    let members = vec![
        String::from("library/std"),
        String::from("library/core"),
        String::from("library/alloc"),
        String::from("library/sysroot"),
    ];
    let ws_config = crate::core::WorkspaceConfig::Root(crate::core::WorkspaceRootConfig::new(
        &src_path,
        &Some(members),
        /*default_members*/ &None,
        /*exclude*/ &None,
        /*inheritable*/ &None,
        /*custom_metadata*/ &None,
    ));
    let virtual_manifest = crate::core::VirtualManifest::new(
        /*replace*/ Vec::new(),
        patch,
        ws_config,
        /*profiles*/ None,
        crate::core::Features::default(),
        None,
    );

    let config = ws.config();
    // This is a delicate hack. In order for features to resolve correctly,
    // the resolver needs to run a specific "current" member of the workspace.
    // Thus, in order to set the features for `std`, we need to set `sysroot`
    // to be the "current" member. `sysroot` is the root, and all other
    // standard library crates are dependencies from there. Since none of the
    // other crates need to alter their features, this should be fine, for
    // now. Perhaps in the future features will be decoupled from the resolver
    // and it will be easier to control feature selection.
    let current_manifest = src_path.join("library/sysroot/Cargo.toml");
    // TODO: Consider doing something to enforce --locked? Or to prevent the
    // lock file from being written, such as setting ephemeral.
    let mut std_ws = Workspace::new_virtual(src_path, current_manifest, virtual_manifest, config)?;
    // Don't require optional dependencies in this workspace, aka std's own
    // `[dev-dependencies]`. No need for us to generate a `Resolve` which has
    // those included because we'll never use them anyway.
    std_ws.set_require_optional_deps(false);
    // `sysroot` is not in the default set because it is optional, but it needs
    // to be part of the resolve in case we do need it or `libtest`.
    let mut spec_pkgs = Vec::from(crates);
    spec_pkgs.push("sysroot".to_string());
    let spec = Packages::Packages(spec_pkgs);
    let specs = spec.to_package_id_specs(&std_ws)?;
    let features = match &config.cli_unstable().build_std_features {
        Some(list) => list.clone(),
        None => vec![
            "panic-unwind".to_string(),
            "backtrace".to_string(),
            "default".to_string(),
        ],
    };
    let cli_features = CliFeatures::from_command_line(
        &features, /*all_features*/ false, /*uses_default_features*/ false,
    )?;
    let max_rust_version = ws.rust_version();
    let resolve = ops::resolve_ws_with_opts(
        &std_ws,
        target_data,
        &build_config.requested_kinds,
        &cli_features,
        &specs,
        HasDevUnits::No,
        crate::core::resolver::features::ForceAllTargets::No,
        max_rust_version,
    )?;
    Ok((
        resolve.pkg_set,
        resolve.targeted_resolve,
        resolve.resolved_features,
    ))
}

/// Generate a list of root `Unit`s for the standard library.
///
/// The given slice of crate names is the root set.
pub fn generate_std_roots(
    crates: &[String],
    std_resolve: &Resolve,
    std_features: &ResolvedFeatures,
    kinds: &[CompileKind],
    package_set: &PackageSet<'_>,
    interner: &UnitInterner,
    profiles: &Profiles,
) -> CargoResult<HashMap<CompileKind, Vec<Unit>>> {
    // Generate the root Units for the standard library.
    let std_ids = crates
        .iter()
        .map(|crate_name| std_resolve.query(crate_name))
        .collect::<CargoResult<Vec<PackageId>>>()?;
    // Convert PackageId to Package.
    let std_pkgs = package_set.get_many(std_ids)?;
    // Generate a map of Units for each kind requested.
    let mut ret = HashMap::new();
    for pkg in std_pkgs {
        let lib = pkg
            .targets()
            .iter()
            .find(|t| t.is_lib())
            .expect("std has a lib");
        // I don't think we need to bother with Check here, the difference
        // in time is minimal, and the difference in caching is
        // significant.
        let mode = CompileMode::Build;
        let features = std_features.activated_features(pkg.package_id(), FeaturesFor::NormalOrDev);
        for kind in kinds {
            let list = ret.entry(*kind).or_insert_with(Vec::new);
            let unit_for = UnitFor::new_normal(*kind);
            let profile = profiles.get_profile(
                pkg.package_id(),
                /*is_member*/ false,
                /*is_local*/ false,
                unit_for,
                *kind,
            );
            list.push(interner.intern(
                pkg,
                lib,
                profile,
                *kind,
                mode,
                features.clone(),
                /*is_std*/ true,
                /*dep_hash*/ 0,
                IsArtifact::No,
                None,
            ));
        }
    }
    Ok(ret)
}

fn detect_sysroot_src_path(target_data: &RustcTargetData<'_>) -> CargoResult<PathBuf> {
    if let Some(s) = target_data.config.get_env_os("__CARGO_TESTS_ONLY_SRC_ROOT") {
        return Ok(s.into());
    }

    // NOTE: This is temporary until we figure out how to acquire the source.
    let src_path = target_data
        .info(CompileKind::Host)
        .sysroot
        .join("lib")
        .join("rustlib")
        .join("src")
        .join("rust");
    let lock = src_path.join("Cargo.lock");
    if !lock.exists() {
        let msg = format!(
            "{:?} does not exist, unable to build with the standard \
             library, try:\n        rustup component add rust-src",
            lock
        );
        match target_data.config.get_env("RUSTUP_TOOLCHAIN") {
            Ok(rustup_toolchain) => {
                anyhow::bail!("{} --toolchain {}", msg, rustup_toolchain);
            }
            Err(_) => {
                anyhow::bail!(msg);
            }
        }
    }
    Ok(src_path)
}