Merge remote-tracking branch 'origin/master'

6 files changed, 1298 insertions, 0 deletions

diff --git a/crates/project_model/Cargo.toml b/crates/project_model/Cargo.toml
new file mode 100644
index 000000000..386f72f41
--- /dev/null
+++ b/crates/project_model/Cargo.toml
@@ -0,0 +1,25 @@
+[package]
+name = "project_model"
+version = "0.0.0"
+license = "MIT OR Apache-2.0"
+authors = ["rust-analyzer developers"]
+edition = "2018"
+
+[lib]
+doctest = false
+
+[dependencies]
+log = "0.4.8"
+rustc-hash = "1.1.0"
+cargo_metadata = "0.11.1"
+serde = { version = "1.0.106", features = ["derive"] }
+serde_json = "1.0.48"
+anyhow = "1.0.26"
+
+arena = { path = "../arena" }
+cfg = { path = "../cfg" }
+base_db = { path = "../base_db" }
+toolchain = { path = "../toolchain" }
+proc_macro_api =  { path = "../proc_macro_api" }
+paths =  { path = "../paths" }
+stdx =  { path = "../stdx" }
diff --git a/crates/project_model/src/cargo_workspace.rs b/crates/project_model/src/cargo_workspace.rs
new file mode 100644
index 000000000..e5c2d2b25
--- /dev/null
+++ b/crates/project_model/src/cargo_workspace.rs
@@ -0,0 +1,362 @@
+//! FIXME: write short doc here
+
+use std::{
+    ffi::OsStr,
+    ops,
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+use anyhow::{Context, Result};
+use arena::{Arena, Idx};
+use base_db::Edition;
+use cargo_metadata::{BuildScript, CargoOpt, Message, MetadataCommand, PackageId};
+use paths::{AbsPath, AbsPathBuf};
+use rustc_hash::FxHashMap;
+
+use crate::cfg_flag::CfgFlag;
+
+/// `CargoWorkspace` represents the logical structure of, well, a Cargo
+/// workspace. It pretty closely mirrors `cargo metadata` output.
+///
+/// Note that internally, rust analyzer uses a different structure:
+/// `CrateGraph`. `CrateGraph` is lower-level: it knows only about the crates,
+/// while this knows about `Packages` & `Targets`: purely cargo-related
+/// concepts.
+///
+/// We use absolute paths here, `cargo metadata` guarantees to always produce
+/// abs paths.
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct CargoWorkspace {
+    packages: Arena<PackageData>,
+    targets: Arena<TargetData>,
+    workspace_root: AbsPathBuf,
+}
+
+impl ops::Index<Package> for CargoWorkspace {
+    type Output = PackageData;
+    fn index(&self, index: Package) -> &PackageData {
+        &self.packages[index]
+    }
+}
+
+impl ops::Index<Target> for CargoWorkspace {
+    type Output = TargetData;
+    fn index(&self, index: Target) -> &TargetData {
+        &self.targets[index]
+    }
+}
+
+#[derive(Default, Clone, Debug, PartialEq, Eq)]
+pub struct CargoConfig {
+    /// Do not activate the `default` feature.
+    pub no_default_features: bool,
+
+    /// Activate all available features
+    pub all_features: bool,
+
+    /// List of features to activate.
+    /// This will be ignored if `cargo_all_features` is true.
+    pub features: Vec<String>,
+
+    /// Runs cargo check on launch to figure out the correct values of OUT_DIR
+    pub load_out_dirs_from_check: bool,
+
+    /// rustc target
+    pub target: Option<String>,
+}
+
+pub type Package = Idx<PackageData>;
+
+pub type Target = Idx<TargetData>;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct PackageData {
+    pub version: String,
+    pub name: String,
+    pub manifest: AbsPathBuf,
+    pub targets: Vec<Target>,
+    pub is_member: bool,
+    pub dependencies: Vec<PackageDependency>,
+    pub edition: Edition,
+    pub features: Vec<String>,
+    pub cfgs: Vec<CfgFlag>,
+    pub out_dir: Option<AbsPathBuf>,
+    pub proc_macro_dylib_path: Option<AbsPathBuf>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct PackageDependency {
+    pub pkg: Package,
+    pub name: String,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TargetData {
+    pub package: Package,
+    pub name: String,
+    pub root: AbsPathBuf,
+    pub kind: TargetKind,
+    pub is_proc_macro: bool,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum TargetKind {
+    Bin,
+    /// Any kind of Cargo lib crate-type (dylib, rlib, proc-macro, ...).
+    Lib,
+    Example,
+    Test,
+    Bench,
+    Other,
+}
+
+impl TargetKind {
+    fn new(kinds: &[String]) -> TargetKind {
+        for kind in kinds {
+            return match kind.as_str() {
+                "bin" => TargetKind::Bin,
+                "test" => TargetKind::Test,
+                "bench" => TargetKind::Bench,
+                "example" => TargetKind::Example,
+                "proc-macro" => TargetKind::Lib,
+                _ if kind.contains("lib") => TargetKind::Lib,
+                _ => continue,
+            };
+        }
+        TargetKind::Other
+    }
+}
+
+impl PackageData {
+    pub fn root(&self) -> &AbsPath {
+        self.manifest.parent().unwrap()
+    }
+}
+
+impl CargoWorkspace {
+    pub fn from_cargo_metadata(
+        cargo_toml: &AbsPath,
+        cargo_features: &CargoConfig,
+    ) -> Result<CargoWorkspace> {
+        let mut meta = MetadataCommand::new();
+        meta.cargo_path(toolchain::cargo());
+        meta.manifest_path(cargo_toml.to_path_buf());
+        if cargo_features.all_features {
+            meta.features(CargoOpt::AllFeatures);
+        } else {
+            if cargo_features.no_default_features {
+                // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
+                // https://github.com/oli-obk/cargo_metadata/issues/79
+                meta.features(CargoOpt::NoDefaultFeatures);
+            }
+            if !cargo_features.features.is_empty() {
+                meta.features(CargoOpt::SomeFeatures(cargo_features.features.clone()));
+            }
+        }
+        if let Some(parent) = cargo_toml.parent() {
+            meta.current_dir(parent.to_path_buf());
+        }
+        if let Some(target) = cargo_features.target.as_ref() {
+            meta.other_options(vec![String::from("--filter-platform"), target.clone()]);
+        }
+        let mut meta = meta.exec().with_context(|| {
+            format!("Failed to run `cargo metadata --manifest-path {}`", cargo_toml.display())
+        })?;
+
+        let mut out_dir_by_id = FxHashMap::default();
+        let mut cfgs = FxHashMap::default();
+        let mut proc_macro_dylib_paths = FxHashMap::default();
+        if cargo_features.load_out_dirs_from_check {
+            let resources = load_extern_resources(cargo_toml, cargo_features)?;
+            out_dir_by_id = resources.out_dirs;
+            cfgs = resources.cfgs;
+            proc_macro_dylib_paths = resources.proc_dylib_paths;
+        }
+
+        let mut pkg_by_id = FxHashMap::default();
+        let mut packages = Arena::default();
+        let mut targets = Arena::default();
+
+        let ws_members = &meta.workspace_members;
+
+        meta.packages.sort_by(|a, b| a.id.cmp(&b.id));
+        for meta_pkg in meta.packages {
+            let cargo_metadata::Package { id, edition, name, manifest_path, version, .. } =
+                meta_pkg;
+            let is_member = ws_members.contains(&id);
+            let edition = edition
+                .parse::<Edition>()
+                .with_context(|| format!("Failed to parse edition {}", edition))?;
+            let pkg = packages.alloc(PackageData {
+                name,
+                version: version.to_string(),
+                manifest: AbsPathBuf::assert(manifest_path),
+                targets: Vec::new(),
+                is_member,
+                edition,
+                dependencies: Vec::new(),
+                features: Vec::new(),
+                cfgs: cfgs.get(&id).cloned().unwrap_or_default(),
+                out_dir: out_dir_by_id.get(&id).cloned(),
+                proc_macro_dylib_path: proc_macro_dylib_paths.get(&id).cloned(),
+            });
+            let pkg_data = &mut packages[pkg];
+            pkg_by_id.insert(id, pkg);
+            for meta_tgt in meta_pkg.targets {
+                let is_proc_macro = meta_tgt.kind.as_slice() == ["proc-macro"];
+                let tgt = targets.alloc(TargetData {
+                    package: pkg,
+                    name: meta_tgt.name,
+                    root: AbsPathBuf::assert(meta_tgt.src_path.clone()),
+                    kind: TargetKind::new(meta_tgt.kind.as_slice()),
+                    is_proc_macro,
+                });
+                pkg_data.targets.push(tgt);
+            }
+        }
+        let resolve = meta.resolve.expect("metadata executed with deps");
+        for mut node in resolve.nodes {
+            let source = match pkg_by_id.get(&node.id) {
+                Some(&src) => src,
+                // FIXME: replace this and a similar branch below with `.unwrap`, once
+                // https://github.com/rust-lang/cargo/issues/7841
+                // is fixed and hits stable (around 1.43-is probably?).
+                None => {
+                    log::error!("Node id do not match in cargo metadata, ignoring {}", node.id);
+                    continue;
+                }
+            };
+            node.deps.sort_by(|a, b| a.pkg.cmp(&b.pkg));
+            for dep_node in node.deps {
+                let pkg = match pkg_by_id.get(&dep_node.pkg) {
+                    Some(&pkg) => pkg,
+                    None => {
+                        log::error!(
+                            "Dep node id do not match in cargo metadata, ignoring {}",
+                            dep_node.pkg
+                        );
+                        continue;
+                    }
+                };
+                let dep = PackageDependency { name: dep_node.name, pkg };
+                packages[source].dependencies.push(dep);
+            }
+            packages[source].features.extend(node.features);
+        }
+
+        let workspace_root = AbsPathBuf::assert(meta.workspace_root);
+        Ok(CargoWorkspace { packages, targets, workspace_root: workspace_root })
+    }
+
+    pub fn packages<'a>(&'a self) -> impl Iterator<Item = Package> + ExactSizeIterator + 'a {
+        self.packages.iter().map(|(id, _pkg)| id)
+    }
+
+    pub fn target_by_root(&self, root: &AbsPath) -> Option<Target> {
+        self.packages()
+            .filter_map(|pkg| self[pkg].targets.iter().find(|&&it| &self[it].root == root))
+            .next()
+            .copied()
+    }
+
+    pub fn workspace_root(&self) -> &AbsPath {
+        &self.workspace_root
+    }
+
+    pub fn package_flag(&self, package: &PackageData) -> String {
+        if self.is_unique(&*package.name) {
+            package.name.clone()
+        } else {
+            format!("{}:{}", package.name, package.version)
+        }
+    }
+
+    fn is_unique(&self, name: &str) -> bool {
+        self.packages.iter().filter(|(_, v)| v.name == name).count() == 1
+    }
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct ExternResources {
+    out_dirs: FxHashMap<PackageId, AbsPathBuf>,
+    proc_dylib_paths: FxHashMap<PackageId, AbsPathBuf>,
+    cfgs: FxHashMap<PackageId, Vec<CfgFlag>>,
+}
+
+pub fn load_extern_resources(
+    cargo_toml: &Path,
+    cargo_features: &CargoConfig,
+) -> Result<ExternResources> {
+    let mut cmd = Command::new(toolchain::cargo());
+    cmd.args(&["check", "--message-format=json", "--manifest-path"]).arg(cargo_toml);
+    if cargo_features.all_features {
+        cmd.arg("--all-features");
+    } else {
+        if cargo_features.no_default_features {
+            // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
+            // https://github.com/oli-obk/cargo_metadata/issues/79
+            cmd.arg("--no-default-features");
+        }
+        if !cargo_features.features.is_empty() {
+            cmd.arg("--features");
+            cmd.arg(cargo_features.features.join(" "));
+        }
+    }
+
+    let output = cmd.output()?;
+
+    let mut res = ExternResources::default();
+
+    for message in cargo_metadata::Message::parse_stream(output.stdout.as_slice()) {
+        if let Ok(message) = message {
+            match message {
+                Message::BuildScriptExecuted(BuildScript { package_id, out_dir, cfgs, .. }) => {
+                    let cfgs = {
+                        let mut acc = Vec::new();
+                        for cfg in cfgs {
+                            match cfg.parse::<CfgFlag>() {
+                                Ok(it) => acc.push(it),
+                                Err(err) => {
+                                    anyhow::bail!("invalid cfg from cargo-metadata: {}", err)
+                                }
+                            };
+                        }
+                        acc
+                    };
+                    // cargo_metadata crate returns default (empty) path for
+                    // older cargos, which is not absolute, so work around that.
+                    if out_dir != PathBuf::default() {
+                        let out_dir = AbsPathBuf::assert(out_dir);
+                        res.out_dirs.insert(package_id.clone(), out_dir);
+                        res.cfgs.insert(package_id, cfgs);
+                    }
+                }
+                Message::CompilerArtifact(message) => {
+                    if message.target.kind.contains(&"proc-macro".to_string()) {
+                        let package_id = message.package_id;
+                        // Skip rmeta file
+                        if let Some(filename) = message.filenames.iter().find(|name| is_dylib(name))
+                        {
+                            let filename = AbsPathBuf::assert(filename.clone());
+                            res.proc_dylib_paths.insert(package_id, filename);
+                        }
+                    }
+                }
+                Message::CompilerMessage(_) => (),
+                Message::Unknown => (),
+                Message::BuildFinished(_) => {}
+                Message::TextLine(_) => {}
+            }
+        }
+    }
+    Ok(res)
+}
+
+// FIXME: File a better way to know if it is a dylib
+fn is_dylib(path: &Path) -> bool {
+    match path.extension().and_then(OsStr::to_str).map(|it| it.to_string().to_lowercase()) {
+        None => false,
+        Some(ext) => matches!(ext.as_str(), "dll" | "dylib" | "so"),
+    }
+}
diff --git a/crates/project_model/src/cfg_flag.rs b/crates/project_model/src/cfg_flag.rs
new file mode 100644
index 000000000..e92962cf6
--- /dev/null
+++ b/crates/project_model/src/cfg_flag.rs
@@ -0,0 +1,51 @@
+//! Parsing of CfgFlags as command line arguments, as in
+//!
+//! rustc main.rs --cfg foo --cfg 'feature="bar"'
+use std::str::FromStr;
+
+use cfg::CfgOptions;
+use stdx::split_once;
+
+#[derive(Clone, Eq, PartialEq, Debug)]
+pub enum CfgFlag {
+    Atom(String),
+    KeyValue { key: String, value: String },
+}
+
+impl FromStr for CfgFlag {
+    type Err = String;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let res = match split_once(s, '=') {
+            Some((key, value)) => {
+                if !(value.starts_with('"') && value.ends_with('"')) {
+                    return Err(format!("Invalid cfg ({:?}), value should be in quotes", s));
+                }
+                let key = key.to_string();
+                let value = value[1..value.len() - 1].to_string();
+                CfgFlag::KeyValue { key, value }
+            }
+            None => CfgFlag::Atom(s.into()),
+        };
+        Ok(res)
+    }
+}
+
+impl<'de> serde::Deserialize<'de> for CfgFlag {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        String::deserialize(deserializer)?.parse().map_err(serde::de::Error::custom)
+    }
+}
+
+impl Extend<CfgFlag> for CfgOptions {
+    fn extend<T: IntoIterator<Item = CfgFlag>>(&mut self, iter: T) {
+        for cfg_flag in iter {
+            match cfg_flag {
+                CfgFlag::Atom(it) => self.insert_atom(it.into()),
+                CfgFlag::KeyValue { key, value } => self.insert_key_value(key.into(), value.into()),
+            }
+        }
+    }
+}
diff --git a/crates/project_model/src/lib.rs b/crates/project_model/src/lib.rs
new file mode 100644
index 000000000..1f5a94d7f
--- /dev/null
+++ b/crates/project_model/src/lib.rs
@@ -0,0 +1,544 @@
+//! FIXME: write short doc here
+
+mod cargo_workspace;
+mod project_json;
+mod sysroot;
+mod cfg_flag;
+
+use std::{
+    fs::{self, read_dir, ReadDir},
+    io,
+    process::Command,
+};
+
+use anyhow::{bail, Context, Result};
+use base_db::{CrateGraph, CrateId, CrateName, Edition, Env, FileId};
+use cfg::CfgOptions;
+use paths::{AbsPath, AbsPathBuf};
+use rustc_hash::{FxHashMap, FxHashSet};
+
+use crate::cfg_flag::CfgFlag;
+
+pub use crate::{
+    cargo_workspace::{CargoConfig, CargoWorkspace, Package, Target, TargetKind},
+    project_json::{ProjectJson, ProjectJsonData},
+    sysroot::Sysroot,
+};
+
+pub use proc_macro_api::ProcMacroClient;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum ProjectWorkspace {
+    /// Project workspace was discovered by running `cargo metadata` and `rustc --print sysroot`.
+    Cargo { cargo: CargoWorkspace, sysroot: Sysroot },
+    /// Project workspace was manually specified using a `rust-project.json` file.
+    Json { project: ProjectJson },
+}
+
+/// `PackageRoot` describes a package root folder.
+/// Which may be an external dependency, or a member of
+/// the current workspace.
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct PackageRoot {
+    /// Is a member of the current workspace
+    pub is_member: bool,
+    pub include: Vec<AbsPathBuf>,
+    pub exclude: Vec<AbsPathBuf>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub enum ProjectManifest {
+    ProjectJson(AbsPathBuf),
+    CargoToml(AbsPathBuf),
+}
+
+impl ProjectManifest {
+    pub fn from_manifest_file(path: AbsPathBuf) -> Result<ProjectManifest> {
+        if path.ends_with("rust-project.json") {
+            return Ok(ProjectManifest::ProjectJson(path));
+        }
+        if path.ends_with("Cargo.toml") {
+            return Ok(ProjectManifest::CargoToml(path));
+        }
+        bail!("project root must point to Cargo.toml or rust-project.json: {}", path.display())
+    }
+
+    pub fn discover_single(path: &AbsPath) -> Result<ProjectManifest> {
+        let mut candidates = ProjectManifest::discover(path)?;
+        let res = match candidates.pop() {
+            None => bail!("no projects"),
+            Some(it) => it,
+        };
+
+        if !candidates.is_empty() {
+            bail!("more than one project")
+        }
+        Ok(res)
+    }
+
+    pub fn discover(path: &AbsPath) -> io::Result<Vec<ProjectManifest>> {
+        if let Some(project_json) = find_in_parent_dirs(path, "rust-project.json") {
+            return Ok(vec![ProjectManifest::ProjectJson(project_json)]);
+        }
+        return find_cargo_toml(path)
+            .map(|paths| paths.into_iter().map(ProjectManifest::CargoToml).collect());
+
+        fn find_cargo_toml(path: &AbsPath) -> io::Result<Vec<AbsPathBuf>> {
+            match find_in_parent_dirs(path, "Cargo.toml") {
+                Some(it) => Ok(vec![it]),
+                None => Ok(find_cargo_toml_in_child_dir(read_dir(path)?)),
+            }
+        }
+
+        fn find_in_parent_dirs(path: &AbsPath, target_file_name: &str) -> Option<AbsPathBuf> {
+            if path.ends_with(target_file_name) {
+                return Some(path.to_path_buf());
+            }
+
+            let mut curr = Some(path);
+
+            while let Some(path) = curr {
+                let candidate = path.join(target_file_name);
+                if candidate.exists() {
+                    return Some(candidate);
+                }
+                curr = path.parent();
+            }
+
+            None
+        }
+
+        fn find_cargo_toml_in_child_dir(entities: ReadDir) -> Vec<AbsPathBuf> {
+            // Only one level down to avoid cycles the easy way and stop a runaway scan with large projects
+            entities
+                .filter_map(Result::ok)
+                .map(|it| it.path().join("Cargo.toml"))
+                .filter(|it| it.exists())
+                .map(AbsPathBuf::assert)
+                .collect()
+        }
+    }
+
+    pub fn discover_all(paths: &[impl AsRef<AbsPath>]) -> Vec<ProjectManifest> {
+        let mut res = paths
+            .iter()
+            .filter_map(|it| ProjectManifest::discover(it.as_ref()).ok())
+            .flatten()
+            .collect::<FxHashSet<_>>()
+            .into_iter()
+            .collect::<Vec<_>>();
+        res.sort();
+        res
+    }
+}
+
+impl ProjectWorkspace {
+    pub fn load(
+        manifest: ProjectManifest,
+        cargo_config: &CargoConfig,
+        with_sysroot: bool,
+    ) -> Result<ProjectWorkspace> {
+        let res = match manifest {
+            ProjectManifest::ProjectJson(project_json) => {
+                let file = fs::read_to_string(&project_json).with_context(|| {
+                    format!("Failed to read json file {}", project_json.display())
+                })?;
+                let data = serde_json::from_str(&file).with_context(|| {
+                    format!("Failed to deserialize json file {}", project_json.display())
+                })?;
+                let project_location = project_json.parent().unwrap().to_path_buf();
+                let project = ProjectJson::new(&project_location, data);
+                ProjectWorkspace::Json { project }
+            }
+            ProjectManifest::CargoToml(cargo_toml) => {
+                let cargo = CargoWorkspace::from_cargo_metadata(&cargo_toml, cargo_config)
+                    .with_context(|| {
+                        format!(
+                            "Failed to read Cargo metadata from Cargo.toml file {}",
+                            cargo_toml.display()
+                        )
+                    })?;
+                let sysroot = if with_sysroot {
+                    Sysroot::discover(&cargo_toml).with_context(|| {
+                        format!(
+                            "Failed to find sysroot for Cargo.toml file {}. Is rust-src installed?",
+                            cargo_toml.display()
+                        )
+                    })?
+                } else {
+                    Sysroot::default()
+                };
+                ProjectWorkspace::Cargo { cargo, sysroot }
+            }
+        };
+
+        Ok(res)
+    }
+
+    /// Returns the roots for the current `ProjectWorkspace`
+    /// The return type contains the path and whether or not
+    /// the root is a member of the current workspace
+    pub fn to_roots(&self) -> Vec<PackageRoot> {
+        match self {
+            ProjectWorkspace::Json { project } => project
+                .crates
+                .iter()
+                .map(|krate| PackageRoot {
+                    is_member: krate.is_workspace_member,
+                    include: krate.include.clone(),
+                    exclude: krate.exclude.clone(),
+                })
+                .collect::<FxHashSet<_>>()
+                .into_iter()
+                .collect::<Vec<_>>(),
+            ProjectWorkspace::Cargo { cargo, sysroot } => cargo
+                .packages()
+                .map(|pkg| {
+                    let is_member = cargo[pkg].is_member;
+                    let pkg_root = cargo[pkg].root().to_path_buf();
+
+                    let mut include = vec![pkg_root.clone()];
+                    include.extend(cargo[pkg].out_dir.clone());
+
+                    let mut exclude = vec![pkg_root.join(".git")];
+                    if is_member {
+                        exclude.push(pkg_root.join("target"));
+                    } else {
+                        exclude.push(pkg_root.join("tests"));
+                        exclude.push(pkg_root.join("examples"));
+                        exclude.push(pkg_root.join("benches"));
+                    }
+                    PackageRoot { is_member, include, exclude }
+                })
+                .chain(sysroot.crates().map(|krate| PackageRoot {
+                    is_member: false,
+                    include: vec![sysroot[krate].root_dir().to_path_buf()],
+                    exclude: Vec::new(),
+                }))
+                .collect(),
+        }
+    }
+
+    pub fn proc_macro_dylib_paths(&self) -> Vec<AbsPathBuf> {
+        match self {
+            ProjectWorkspace::Json { project } => project
+                .crates
+                .iter()
+                .filter_map(|krate| krate.proc_macro_dylib_path.as_ref())
+                .cloned()
+                .collect(),
+            ProjectWorkspace::Cargo { cargo, sysroot: _sysroot } => cargo
+                .packages()
+                .filter_map(|pkg| cargo[pkg].proc_macro_dylib_path.as_ref())
+                .cloned()
+                .collect(),
+        }
+    }
+
+    pub fn n_packages(&self) -> usize {
+        match self {
+            ProjectWorkspace::Json { project, .. } => project.crates.len(),
+            ProjectWorkspace::Cargo { cargo, sysroot } => {
+                cargo.packages().len() + sysroot.crates().len()
+            }
+        }
+    }
+
+    pub fn to_crate_graph(
+        &self,
+        target: Option<&str>,
+        proc_macro_client: &ProcMacroClient,
+        load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
+    ) -> CrateGraph {
+        let mut crate_graph = CrateGraph::default();
+        match self {
+            ProjectWorkspace::Json { project } => {
+                let mut cfg_cache: FxHashMap<Option<&str>, Vec<CfgFlag>> = FxHashMap::default();
+                let crates: FxHashMap<_, _> = project
+                    .crates
+                    .iter()
+                    .enumerate()
+                    .filter_map(|(seq_index, krate)| {
+                        let file_path = &krate.root_module;
+                        let file_id = load(&file_path)?;
+
+                        let env = krate.env.clone().into_iter().collect();
+                        let proc_macro = krate
+                            .proc_macro_dylib_path
+                            .clone()
+                            .map(|it| proc_macro_client.by_dylib_path(&it));
+
+                        let target = krate.target.as_deref().or(target);
+                        let target_cfgs = cfg_cache
+                            .entry(target)
+                            .or_insert_with(|| get_rustc_cfg_options(target));
+
+                        let mut cfg_options = CfgOptions::default();
+                        cfg_options.extend(target_cfgs.iter().chain(krate.cfg.iter()).cloned());
+
+                        // FIXME: No crate name in json definition such that we cannot add OUT_DIR to env
+                        Some((
+                            CrateId(seq_index as u32),
+                            crate_graph.add_crate_root(
+                                file_id,
+                                krate.edition,
+                                // FIXME json definitions can store the crate name
+                                None,
+                                cfg_options,
+                                env,
+                                proc_macro.unwrap_or_default(),
+                            ),
+                        ))
+                    })
+                    .collect();
+
+                for (id, krate) in project.crates.iter().enumerate() {
+                    for dep in &krate.deps {
+                        let from_crate_id = CrateId(id as u32);
+                        let to_crate_id = dep.crate_id;
+                        if let (Some(&from), Some(&to)) =
+                            (crates.get(&from_crate_id), crates.get(&to_crate_id))
+                        {
+                            if crate_graph.add_dep(from, dep.name.clone(), to).is_err() {
+                                log::error!(
+                                    "cyclic dependency {:?} -> {:?}",
+                                    from_crate_id,
+                                    to_crate_id
+                                );
+                            }
+                        }
+                    }
+                }
+            }
+            ProjectWorkspace::Cargo { cargo, sysroot } => {
+                let mut cfg_options = CfgOptions::default();
+                cfg_options.extend(get_rustc_cfg_options(target));
+
+                let sysroot_crates: FxHashMap<_, _> = sysroot
+                    .crates()
+                    .filter_map(|krate| {
+                        let file_id = load(&sysroot[krate].root)?;
+
+                        let env = Env::default();
+                        let proc_macro = vec![];
+                        let name = sysroot[krate].name.clone();
+                        let crate_id = crate_graph.add_crate_root(
+                            file_id,
+                            Edition::Edition2018,
+                            Some(name),
+                            cfg_options.clone(),
+                            env,
+                            proc_macro,
+                        );
+                        Some((krate, crate_id))
+                    })
+                    .collect();
+
+                for from in sysroot.crates() {
+                    for &to in sysroot[from].deps.iter() {
+                        let name = &sysroot[to].name;
+                        if let (Some(&from), Some(&to)) =
+                            (sysroot_crates.get(&from), sysroot_crates.get(&to))
+                        {
+                            if crate_graph.add_dep(from, CrateName::new(name).unwrap(), to).is_err()
+                            {
+                                log::error!("cyclic dependency between sysroot crates")
+                            }
+                        }
+                    }
+                }
+
+                let libcore = sysroot.core().and_then(|it| sysroot_crates.get(&it).copied());
+                let liballoc = sysroot.alloc().and_then(|it| sysroot_crates.get(&it).copied());
+                let libstd = sysroot.std().and_then(|it| sysroot_crates.get(&it).copied());
+                let libproc_macro =
+                    sysroot.proc_macro().and_then(|it| sysroot_crates.get(&it).copied());
+
+                let mut pkg_to_lib_crate = FxHashMap::default();
+                let mut pkg_crates = FxHashMap::default();
+
+                // Add test cfg for non-sysroot crates
+                cfg_options.insert_atom("test".into());
+                cfg_options.insert_atom("debug_assertions".into());
+
+                // Next, create crates for each package, target pair
+                for pkg in cargo.packages() {
+                    let mut lib_tgt = None;
+                    for &tgt in cargo[pkg].targets.iter() {
+                        let root = cargo[tgt].root.as_path();
+                        if let Some(file_id) = load(root) {
+                            let edition = cargo[pkg].edition;
+                            let cfg_options = {
+                                let mut opts = cfg_options.clone();
+                                for feature in cargo[pkg].features.iter() {
+                                    opts.insert_key_value("feature".into(), feature.into());
+                                }
+                                opts.extend(cargo[pkg].cfgs.iter().cloned());
+                                opts
+                            };
+                            let mut env = Env::default();
+                            if let Some(out_dir) = &cargo[pkg].out_dir {
+                                // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
+                                if let Some(out_dir) = out_dir.to_str().map(|s| s.to_owned()) {
+                                    env.set("OUT_DIR", out_dir);
+                                }
+                            }
+                            let proc_macro = cargo[pkg]
+                                .proc_macro_dylib_path
+                                .as_ref()
+                                .map(|it| proc_macro_client.by_dylib_path(&it))
+                                .unwrap_or_default();
+
+                            let crate_id = crate_graph.add_crate_root(
+                                file_id,
+                                edition,
+                                Some(cargo[pkg].name.clone()),
+                                cfg_options,
+                                env,
+                                proc_macro.clone(),
+                            );
+                            if cargo[tgt].kind == TargetKind::Lib {
+                                lib_tgt = Some((crate_id, cargo[tgt].name.clone()));
+                                pkg_to_lib_crate.insert(pkg, crate_id);
+                            }
+                            if cargo[tgt].is_proc_macro {
+                                if let Some(proc_macro) = libproc_macro {
+                                    if crate_graph
+                                        .add_dep(
+                                            crate_id,
+                                            CrateName::new("proc_macro").unwrap(),
+                                            proc_macro,
+                                        )
+                                        .is_err()
+                                    {
+                                        log::error!(
+                                            "cyclic dependency on proc_macro for {}",
+                                            &cargo[pkg].name
+                                        )
+                                    }
+                                }
+                            }
+
+                            pkg_crates.entry(pkg).or_insert_with(Vec::new).push(crate_id);
+                        }
+                    }
+
+                    // Set deps to the core, std and to the lib target of the current package
+                    for &from in pkg_crates.get(&pkg).into_iter().flatten() {
+                        if let Some((to, name)) = lib_tgt.clone() {
+                            if to != from
+                                && crate_graph
+                                    .add_dep(
+                                        from,
+                                        // For root projects with dashes in their name,
+                                        // cargo metadata does not do any normalization,
+                                        // so we do it ourselves currently
+                                        CrateName::normalize_dashes(&name),
+                                        to,
+                                    )
+                                    .is_err()
+                            {
+                                {
+                                    log::error!(
+                                        "cyclic dependency between targets of {}",
+                                        &cargo[pkg].name
+                                    )
+                                }
+                            }
+                        }
+                        // core is added as a dependency before std in order to
+                        // mimic rustcs dependency order
+                        if let Some(core) = libcore {
+                            if crate_graph
+                                .add_dep(from, CrateName::new("core").unwrap(), core)
+                                .is_err()
+                            {
+                                log::error!("cyclic dependency on core for {}", &cargo[pkg].name)
+                            }
+                        }
+                        if let Some(alloc) = liballoc {
+                            if crate_graph
+                                .add_dep(from, CrateName::new("alloc").unwrap(), alloc)
+                                .is_err()
+                            {
+                                log::error!("cyclic dependency on alloc for {}", &cargo[pkg].name)
+                            }
+                        }
+                        if let Some(std) = libstd {
+                            if crate_graph
+                                .add_dep(from, CrateName::new("std").unwrap(), std)
+                                .is_err()
+                            {
+                                log::error!("cyclic dependency on std for {}", &cargo[pkg].name)
+                            }
+                        }
+                    }
+                }
+
+                // Now add a dep edge from all targets of upstream to the lib
+                // target of downstream.
+                for pkg in cargo.packages() {
+                    for dep in cargo[pkg].dependencies.iter() {
+                        if let Some(&to) = pkg_to_lib_crate.get(&dep.pkg) {
+                            for &from in pkg_crates.get(&pkg).into_iter().flatten() {
+                                if crate_graph
+                                    .add_dep(from, CrateName::new(&dep.name).unwrap(), to)
+                                    .is_err()
+                                {
+                                    log::error!(
+                                        "cyclic dependency {} -> {}",
+                                        &cargo[pkg].name,
+                                        &cargo[dep.pkg].name
+                                    )
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        crate_graph
+    }
+}
+
+fn get_rustc_cfg_options(target: Option<&str>) -> Vec<CfgFlag> {
+    let mut res = Vec::new();
+
+    // Some nightly-only cfgs, which are required for stdlib
+    res.push(CfgFlag::Atom("target_thread_local".into()));
+    for &ty in ["8", "16", "32", "64", "cas", "ptr"].iter() {
+        for &key in ["target_has_atomic", "target_has_atomic_load_store"].iter() {
+            res.push(CfgFlag::KeyValue { key: key.to_string(), value: ty.into() });
+        }
+    }
+
+    let rustc_cfgs = {
+        let mut cmd = Command::new(toolchain::rustc());
+        cmd.args(&["--print", "cfg", "-O"]);
+        if let Some(target) = target {
+            cmd.args(&["--target", target]);
+        }
+        utf8_stdout(cmd)
+    };
+
+    match rustc_cfgs {
+        Ok(rustc_cfgs) => res.extend(rustc_cfgs.lines().map(|it| it.parse().unwrap())),
+        Err(e) => log::error!("failed to get rustc cfgs: {:#}", e),
+    }
+
+    res
+}
+
+fn utf8_stdout(mut cmd: Command) -> Result<String> {
+    let output = cmd.output().with_context(|| format!("{:?} failed", cmd))?;
+    if !output.status.success() {
+        match String::from_utf8(output.stderr) {
+            Ok(stderr) if !stderr.is_empty() => {
+                bail!("{:?} failed, {}\nstderr:\n{}", cmd, output.status, stderr)
+            }
+            _ => bail!("{:?} failed, {}", cmd, output.status),
+        }
+    }
+    let stdout = String::from_utf8(output.stdout)?;
+    Ok(stdout)
+}
diff --git a/crates/project_model/src/project_json.rs b/crates/project_model/src/project_json.rs
new file mode 100644
index 000000000..060ea5b7d
--- /dev/null
+++ b/crates/project_model/src/project_json.rs
@@ -0,0 +1,143 @@
+//! FIXME: write short doc here
+
+use std::path::PathBuf;
+
+use base_db::{CrateId, CrateName, Dependency, Edition};
+use paths::{AbsPath, AbsPathBuf};
+use rustc_hash::FxHashMap;
+use serde::{de, Deserialize};
+
+use crate::cfg_flag::CfgFlag;
+
+/// Roots and crates that compose this Rust project.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct ProjectJson {
+    pub(crate) crates: Vec<Crate>,
+}
+
+/// A crate points to the root module of a crate and lists the dependencies of the crate. This is
+/// useful in creating the crate graph.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct Crate {
+    pub(crate) root_module: AbsPathBuf,
+    pub(crate) edition: Edition,
+    pub(crate) deps: Vec<Dependency>,
+    pub(crate) cfg: Vec<CfgFlag>,
+    pub(crate) target: Option<String>,
+    pub(crate) env: FxHashMap<String, String>,
+    pub(crate) proc_macro_dylib_path: Option<AbsPathBuf>,
+    pub(crate) is_workspace_member: bool,
+    pub(crate) include: Vec<AbsPathBuf>,
+    pub(crate) exclude: Vec<AbsPathBuf>,
+}
+
+impl ProjectJson {
+    pub fn new(base: &AbsPath, data: ProjectJsonData) -> ProjectJson {
+        ProjectJson {
+            crates: data
+                .crates
+                .into_iter()
+                .map(|crate_data| {
+                    let is_workspace_member = crate_data.is_workspace_member.unwrap_or_else(|| {
+                        crate_data.root_module.is_relative()
+                            && !crate_data.root_module.starts_with("..")
+                            || crate_data.root_module.starts_with(base)
+                    });
+                    let root_module = base.join(crate_data.root_module);
+                    let (include, exclude) = match crate_data.source {
+                        Some(src) => {
+                            let absolutize = |dirs: Vec<PathBuf>| {
+                                dirs.into_iter().map(|it| base.join(it)).collect::<Vec<_>>()
+                            };
+                            (absolutize(src.include_dirs), absolutize(src.exclude_dirs))
+                        }
+                        None => (vec![root_module.parent().unwrap().to_path_buf()], Vec::new()),
+                    };
+
+                    Crate {
+                        root_module,
+                        edition: crate_data.edition.into(),
+                        deps: crate_data
+                            .deps
+                            .into_iter()
+                            .map(|dep_data| Dependency {
+                                crate_id: CrateId(dep_data.krate as u32),
+                                name: dep_data.name,
+                            })
+                            .collect::<Vec<_>>(),
+                        cfg: crate_data.cfg,
+                        target: crate_data.target,
+                        env: crate_data.env,
+                        proc_macro_dylib_path: crate_data
+                            .proc_macro_dylib_path
+                            .map(|it| base.join(it)),
+                        is_workspace_member,
+                        include,
+                        exclude,
+                    }
+                })
+                .collect::<Vec<_>>(),
+        }
+    }
+}
+
+#[derive(Deserialize)]
+pub struct ProjectJsonData {
+    crates: Vec<CrateData>,
+}
+
+#[derive(Deserialize)]
+struct CrateData {
+    root_module: PathBuf,
+    edition: EditionData,
+    deps: Vec<DepData>,
+    #[serde(default)]
+    cfg: Vec<CfgFlag>,
+    target: Option<String>,
+    #[serde(default)]
+    env: FxHashMap<String, String>,
+    proc_macro_dylib_path: Option<PathBuf>,
+    is_workspace_member: Option<bool>,
+    source: Option<CrateSource>,
+}
+
+#[derive(Deserialize)]
+#[serde(rename = "edition")]
+enum EditionData {
+    #[serde(rename = "2015")]
+    Edition2015,
+    #[serde(rename = "2018")]
+    Edition2018,
+}
+
+impl From<EditionData> for Edition {
+    fn from(data: EditionData) -> Self {
+        match data {
+            EditionData::Edition2015 => Edition::Edition2015,
+            EditionData::Edition2018 => Edition::Edition2018,
+        }
+    }
+}
+
+#[derive(Deserialize)]
+struct DepData {
+    /// Identifies a crate by position in the crates array.
+    #[serde(rename = "crate")]
+    krate: usize,
+    #[serde(deserialize_with = "deserialize_crate_name")]
+    name: CrateName,
+}
+
+#[derive(Deserialize)]
+struct CrateSource {
+    include_dirs: Vec<PathBuf>,
+    exclude_dirs: Vec<PathBuf>,
+}
+
+fn deserialize_crate_name<'de, D>(de: D) -> Result<CrateName, D::Error>
+where
+    D: de::Deserializer<'de>,
+{
+    let name = String::deserialize(de)?;
+    CrateName::new(&name).map_err(|err| de::Error::custom(format!("invalid crate name: {:?}", err)))
+}
diff --git a/crates/project_model/src/sysroot.rs b/crates/project_model/src/sysroot.rs
new file mode 100644
index 000000000..8239797b6
--- /dev/null
+++ b/crates/project_model/src/sysroot.rs
@@ -0,0 +1,173 @@
+//! FIXME: write short doc here
+
+use std::{convert::TryFrom, env, ops, path::Path, process::Command};
+
+use anyhow::{bail, format_err, Result};
+use arena::{Arena, Idx};
+use paths::{AbsPath, AbsPathBuf};
+
+use crate::utf8_stdout;
+
+#[derive(Default, Debug, Clone, Eq, PartialEq)]
+pub struct Sysroot {
+    crates: Arena<SysrootCrateData>,
+}
+
+pub type SysrootCrate = Idx<SysrootCrateData>;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct SysrootCrateData {
+    pub name: String,
+    pub root: AbsPathBuf,
+    pub deps: Vec<SysrootCrate>,
+}
+
+impl ops::Index<SysrootCrate> for Sysroot {
+    type Output = SysrootCrateData;
+    fn index(&self, index: SysrootCrate) -> &SysrootCrateData {
+        &self.crates[index]
+    }
+}
+
+impl Sysroot {
+    pub fn core(&self) -> Option<SysrootCrate> {
+        self.by_name("core")
+    }
+
+    pub fn alloc(&self) -> Option<SysrootCrate> {
+        self.by_name("alloc")
+    }
+
+    pub fn std(&self) -> Option<SysrootCrate> {
+        self.by_name("std")
+    }
+
+    pub fn proc_macro(&self) -> Option<SysrootCrate> {
+        self.by_name("proc_macro")
+    }
+
+    pub fn crates<'a>(&'a self) -> impl Iterator<Item = SysrootCrate> + ExactSizeIterator + 'a {
+        self.crates.iter().map(|(id, _data)| id)
+    }
+
+    pub fn discover(cargo_toml: &AbsPath) -> Result<Sysroot> {
+        let src = get_or_install_rust_src(cargo_toml)?;
+        let mut sysroot = Sysroot { crates: Arena::default() };
+        for name in SYSROOT_CRATES.trim().lines() {
+            // FIXME: remove this path when 1.47 comes out
+            // https://github.com/rust-lang/rust/pull/73265
+            let root = src.join(format!("lib{}", name)).join("lib.rs");
+            if root.exists() {
+                sysroot.crates.alloc(SysrootCrateData {
+                    name: name.into(),
+                    root,
+                    deps: Vec::new(),
+                });
+            } else {
+                let root = src.join(name).join("src/lib.rs");
+                if root.exists() {
+                    sysroot.crates.alloc(SysrootCrateData {
+                        name: name.into(),
+                        root,
+                        deps: Vec::new(),
+                    });
+                }
+            }
+        }
+        if let Some(std) = sysroot.std() {
+            for dep in STD_DEPS.trim().lines() {
+                if let Some(dep) = sysroot.by_name(dep) {
+                    sysroot.crates[std].deps.push(dep)
+                }
+            }
+        }
+        if let Some(alloc) = sysroot.alloc() {
+            if let Some(core) = sysroot.core() {
+                sysroot.crates[alloc].deps.push(core);
+            }
+        }
+        Ok(sysroot)
+    }
+
+    fn by_name(&self, name: &str) -> Option<SysrootCrate> {
+        self.crates.iter().find(|(_id, data)| data.name == name).map(|(id, _data)| id)
+    }
+}
+
+fn get_or_install_rust_src(cargo_toml: &AbsPath) -> Result<AbsPathBuf> {
+    if let Ok(path) = env::var("RUST_SRC_PATH") {
+        let path = AbsPathBuf::try_from(path.as_str())
+            .map_err(|path| format_err!("RUST_SRC_PATH must be absolute: {}", path.display()))?;
+        return Ok(path);
+    }
+    let current_dir = cargo_toml.parent().unwrap();
+    let mut rustc = Command::new(toolchain::rustc());
+    rustc.current_dir(current_dir).args(&["--print", "sysroot"]);
+    let stdout = utf8_stdout(rustc)?;
+    let sysroot_path = AbsPath::assert(Path::new(stdout.trim()));
+    let mut src = get_rust_src(sysroot_path);
+    if src.is_none() {
+        let mut rustup = Command::new(toolchain::rustup());
+        rustup.current_dir(current_dir).args(&["component", "add", "rust-src"]);
+        utf8_stdout(rustup)?;
+        src = get_rust_src(sysroot_path);
+    }
+    match src {
+        Some(r) => Ok(r),
+        None => bail!(
+            "can't load standard library from sysroot\n\
+            {}\n\
+            (discovered via `rustc --print sysroot`)\n\
+            try running `rustup component add rust-src` or set `RUST_SRC_PATH`",
+            sysroot_path.display(),
+        ),
+    }
+}
+
+fn get_rust_src(sysroot_path: &AbsPath) -> Option<AbsPathBuf> {
+    // try the new path first since the old one still exists
+    let mut src_path = sysroot_path.join("lib/rustlib/src/rust/library");
+    if !src_path.exists() {
+        // FIXME: remove this path when 1.47 comes out
+        // https://github.com/rust-lang/rust/pull/73265
+        src_path = sysroot_path.join("lib/rustlib/src/rust/src");
+    }
+    if src_path.exists() {
+        Some(src_path)
+    } else {
+        None
+    }
+}
+
+impl SysrootCrateData {
+    pub fn root_dir(&self) -> &AbsPath {
+        self.root.parent().unwrap()
+    }
+}
+
+const SYSROOT_CRATES: &str = "
+alloc
+core
+panic_abort
+panic_unwind
+proc_macro
+profiler_builtins
+rtstartup
+std
+stdarch
+term
+test
+unwind";
+
+const STD_DEPS: &str = "
+alloc
+core
+panic_abort
+panic_unwind
+profiler_builtins
+rtstartup
+proc_macro
+stdarch
+term
+test
+unwind";