6 files changed, 333 insertions, 261 deletions

diff --git a/crates/project_model/Cargo.toml b/crates/project_model/Cargo.toml
index 436eff16b..293cb5bfe 100644
--- a/crates/project_model/Cargo.toml
+++ b/crates/project_model/Cargo.toml
@@ -25,3 +25,4 @@ toolchain = { path = "../toolchain", version = "0.0.0" }
 proc_macro_api =  { path = "../proc_macro_api", version = "0.0.0" }
 paths =  { path = "../paths", version = "0.0.0" }
 stdx =  { path = "../stdx", version = "0.0.0" }
+profile =  { path = "../profile", version = "0.0.0" }
diff --git a/crates/project_model/src/build_data.rs b/crates/project_model/src/build_data.rs
new file mode 100644
index 000000000..cf32995e0
--- /dev/null
+++ b/crates/project_model/src/build_data.rs
@@ -0,0 +1,206 @@
+//! Handles build script specific information
+
+use std::{
+    ffi::OsStr,
+    io::BufReader,
+    path::{Path, PathBuf},
+    process::{Command, Stdio},
+};
+
+use anyhow::Result;
+use cargo_metadata::{BuildScript, Message, Package, PackageId};
+use itertools::Itertools;
+use paths::{AbsPath, AbsPathBuf};
+use rustc_hash::FxHashMap;
+use stdx::JodChild;
+
+use crate::{cfg_flag::CfgFlag, CargoConfig};
+
+#[derive(Debug, Clone, Default)]
+pub(crate) struct BuildDataMap {
+    data: FxHashMap<PackageId, BuildData>,
+}
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub struct BuildData {
+    /// List of config flags defined by this package's build script
+    pub cfgs: Vec<CfgFlag>,
+    /// List of cargo-related environment variables with their value
+    ///
+    /// If the package has a build script which defines environment variables,
+    /// they can also be found here.
+    pub envs: Vec<(String, String)>,
+    /// Directory where a build script might place its output
+    pub out_dir: Option<AbsPathBuf>,
+    /// Path to the proc-macro library file if this package exposes proc-macros
+    pub proc_macro_dylib_path: Option<AbsPathBuf>,
+}
+
+impl BuildDataMap {
+    pub(crate) fn new(
+        cargo_toml: &AbsPath,
+        cargo_features: &CargoConfig,
+        packages: &Vec<Package>,
+        progress: &dyn Fn(String),
+    ) -> Result<BuildDataMap> {
+        let mut cmd = Command::new(toolchain::cargo());
+        cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"])
+            .arg(cargo_toml.as_ref());
+
+        // --all-targets includes tests, benches and examples in addition to the
+        // default lib and bins. This is an independent concept from the --targets
+        // flag below.
+        cmd.arg("--all-targets");
+
+        if let Some(target) = &cargo_features.target {
+            cmd.args(&["--target", target]);
+        }
+
+        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(" "));
+            }
+        }
+
+        cmd.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
+
+        let mut child = cmd.spawn().map(JodChild)?;
+        let child_stdout = child.stdout.take().unwrap();
+        let stdout = BufReader::new(child_stdout);
+
+        let mut res = BuildDataMap::default();
+        for message in cargo_metadata::Message::parse_stream(stdout) {
+            if let Ok(message) = message {
+                match message {
+                    Message::BuildScriptExecuted(BuildScript {
+                        package_id,
+                        out_dir,
+                        cfgs,
+                        env,
+                        ..
+                    }) => {
+                        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
+                        };
+                        let res = res.data.entry(package_id.clone()).or_default();
+                        // 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_dir = Some(out_dir);
+                            res.cfgs = cfgs;
+                        }
+
+                        res.envs = env;
+                    }
+                    Message::CompilerArtifact(message) => {
+                        progress(format!("metadata {}", message.target.name));
+
+                        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());
+                                let res = res.data.entry(package_id.clone()).or_default();
+                                res.proc_macro_dylib_path = Some(filename);
+                            }
+                        }
+                    }
+                    Message::CompilerMessage(message) => {
+                        progress(message.target.name.clone());
+                    }
+                    Message::Unknown => (),
+                    Message::BuildFinished(_) => {}
+                    Message::TextLine(_) => {}
+                }
+            }
+        }
+        res.inject_cargo_env(packages);
+        Ok(res)
+    }
+
+    pub(crate) fn with_cargo_env(packages: &Vec<Package>) -> Self {
+        let mut res = Self::default();
+        res.inject_cargo_env(packages);
+        res
+    }
+
+    pub(crate) fn get(&self, id: &PackageId) -> Option<&BuildData> {
+        self.data.get(id)
+    }
+
+    fn inject_cargo_env(&mut self, packages: &Vec<Package>) {
+        for meta_pkg in packages {
+            let resource = self.data.entry(meta_pkg.id.clone()).or_default();
+            inject_cargo_env(meta_pkg, &mut resource.envs);
+
+            if let Some(out_dir) = &resource.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()) {
+                    resource.envs.push(("OUT_DIR".to_string(), out_dir));
+                }
+            }
+        }
+    }
+}
+
+// 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"),
+    }
+}
+
+/// Recreates the compile-time environment variables that Cargo sets.
+///
+/// Should be synced with <https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>
+fn inject_cargo_env(package: &cargo_metadata::Package, env: &mut Vec<(String, String)>) {
+    // FIXME: Missing variables:
+    // CARGO, CARGO_PKG_HOMEPAGE, CARGO_CRATE_NAME, CARGO_BIN_NAME, CARGO_BIN_EXE_<name>
+
+    let mut manifest_dir = package.manifest_path.clone();
+    manifest_dir.pop();
+    if let Some(cargo_manifest_dir) = manifest_dir.to_str() {
+        env.push(("CARGO_MANIFEST_DIR".into(), cargo_manifest_dir.into()));
+    }
+
+    env.push(("CARGO_PKG_VERSION".into(), package.version.to_string()));
+    env.push(("CARGO_PKG_VERSION_MAJOR".into(), package.version.major.to_string()));
+    env.push(("CARGO_PKG_VERSION_MINOR".into(), package.version.minor.to_string()));
+    env.push(("CARGO_PKG_VERSION_PATCH".into(), package.version.patch.to_string()));
+
+    let pre = package.version.pre.iter().map(|id| id.to_string()).format(".");
+    env.push(("CARGO_PKG_VERSION_PRE".into(), pre.to_string()));
+
+    let authors = package.authors.join(";");
+    env.push(("CARGO_PKG_AUTHORS".into(), authors));
+
+    env.push(("CARGO_PKG_NAME".into(), package.name.clone()));
+    env.push(("CARGO_PKG_DESCRIPTION".into(), package.description.clone().unwrap_or_default()));
+    //env.push(("CARGO_PKG_HOMEPAGE".into(), package.homepage.clone().unwrap_or_default()));
+    env.push(("CARGO_PKG_REPOSITORY".into(), package.repository.clone().unwrap_or_default()));
+    env.push(("CARGO_PKG_LICENSE".into(), package.license.clone().unwrap_or_default()));
+
+    let license_file =
+        package.license_file.as_ref().map(|buf| buf.display().to_string()).unwrap_or_default();
+    env.push(("CARGO_PKG_LICENSE_FILE".into(), license_file));
+}
diff --git a/crates/project_model/src/cargo_workspace.rs b/crates/project_model/src/cargo_workspace.rs
index c0ed37fc1..c8a5333c4 100644
--- a/crates/project_model/src/cargo_workspace.rs
+++ b/crates/project_model/src/cargo_workspace.rs
@@ -1,24 +1,15 @@
 //! FIXME: write short doc here
 
-use std::{
-    convert::TryInto,
-    ffi::OsStr,
-    io::BufReader,
-    ops,
-    path::{Path, PathBuf},
-    process::{Command, Stdio},
-};
+use std::{convert::TryInto, ops, process::Command};
 
 use anyhow::{Context, Result};
 use base_db::Edition;
-use cargo_metadata::{BuildScript, CargoOpt, Message, MetadataCommand, PackageId};
-use itertools::Itertools;
+use cargo_metadata::{CargoOpt, MetadataCommand};
 use la_arena::{Arena, Idx};
 use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::FxHashMap;
-use stdx::JodChild;
 
-use crate::cfg_flag::CfgFlag;
+use crate::build_data::{BuildData, BuildDataMap};
 use crate::utf8_stdout;
 
 /// `CargoWorkspace` represents the logical structure of, well, a Cargo
@@ -99,19 +90,12 @@ pub struct PackageData {
     pub dependencies: Vec<PackageDependency>,
     /// Rust edition for this package
     pub edition: Edition,
-    /// List of features to activate
-    pub features: Vec<String>,
-    /// List of config flags defined by this package's build script
-    pub cfgs: Vec<CfgFlag>,
-    /// List of cargo-related environment variables with their value
-    ///
-    /// If the package has a build script which defines environment variables,
-    /// they can also be found here.
-    pub envs: Vec<(String, String)>,
-    /// Directory where a build script might place its output
-    pub out_dir: Option<AbsPathBuf>,
-    /// Path to the proc-macro library file if this package exposes proc-macros
-    pub proc_macro_dylib_path: Option<AbsPathBuf>,
+    /// Features provided by the crate, mapped to the features required by that feature.
+    pub features: FxHashMap<String, Vec<String>>,
+    /// List of features enabled on this package
+    pub active_features: Vec<String>,
+    /// Build script related data for this package
+    pub build_data: BuildData,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -244,17 +228,11 @@ impl CargoWorkspace {
             )
         })?;
 
-        let mut out_dir_by_id = FxHashMap::default();
-        let mut cfgs = FxHashMap::default();
-        let mut envs = FxHashMap::default();
-        let mut proc_macro_dylib_paths = FxHashMap::default();
-        if config.load_out_dirs_from_check {
-            let resources = load_extern_resources(cargo_toml, config, progress)?;
-            out_dir_by_id = resources.out_dirs;
-            cfgs = resources.cfgs;
-            envs = resources.env;
-            proc_macro_dylib_paths = resources.proc_dylib_paths;
-        }
+        let resources = if config.load_out_dirs_from_check {
+            BuildDataMap::new(cargo_toml, config, &meta.packages, progress)?
+        } else {
+            BuildDataMap::with_cargo_env(&meta.packages)
+        };
 
         let mut pkg_by_id = FxHashMap::default();
         let mut packages = Arena::default();
@@ -265,7 +243,7 @@ impl CargoWorkspace {
         meta.packages.sort_by(|a, b| a.id.cmp(&b.id));
         for meta_pkg in meta.packages {
             let id = meta_pkg.id.clone();
-            inject_cargo_env(&meta_pkg, envs.entry(id).or_default());
+            let build_data = resources.get(&id).cloned().unwrap_or_default();
 
             let cargo_metadata::Package { id, edition, name, manifest_path, version, .. } =
                 meta_pkg;
@@ -281,11 +259,9 @@ impl CargoWorkspace {
                 is_member,
                 edition,
                 dependencies: Vec::new(),
-                features: Vec::new(),
-                cfgs: cfgs.get(&id).cloned().unwrap_or_default(),
-                envs: envs.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(),
+                features: meta_pkg.features.into_iter().collect(),
+                active_features: Vec::new(),
+                build_data,
             });
             let pkg_data = &mut packages[pkg];
             pkg_by_id.insert(id, pkg);
@@ -328,7 +304,7 @@ impl CargoWorkspace {
                 let dep = PackageDependency { name: dep_node.name, pkg };
                 packages[source].dependencies.push(dep);
             }
-            packages[source].features.extend(node.features);
+            packages[source].active_features.extend(node.features);
         }
 
         let workspace_root = AbsPathBuf::assert(meta.workspace_root);
@@ -362,149 +338,3 @@ impl CargoWorkspace {
         self.packages.iter().filter(|(_, v)| v.name == name).count() == 1
     }
 }
-
-#[derive(Debug, Clone, Default)]
-pub(crate) struct ExternResources {
-    out_dirs: FxHashMap<PackageId, AbsPathBuf>,
-    proc_dylib_paths: FxHashMap<PackageId, AbsPathBuf>,
-    cfgs: FxHashMap<PackageId, Vec<CfgFlag>>,
-    env: FxHashMap<PackageId, Vec<(String, String)>>,
-}
-
-pub(crate) fn load_extern_resources(
-    cargo_toml: &Path,
-    cargo_features: &CargoConfig,
-    progress: &dyn Fn(String),
-) -> Result<ExternResources> {
-    let mut cmd = Command::new(toolchain::cargo());
-    cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"]).arg(cargo_toml);
-
-    // --all-targets includes tests, benches and examples in addition to the
-    // default lib and bins. This is an independent concept from the --targets
-    // flag below.
-    cmd.arg("--all-targets");
-
-    if let Some(target) = &cargo_features.target {
-        cmd.args(&["--target", target]);
-    }
-
-    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(" "));
-        }
-    }
-
-    cmd.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
-
-    let mut child = cmd.spawn().map(JodChild)?;
-    let child_stdout = child.stdout.take().unwrap();
-    let stdout = BufReader::new(child_stdout);
-
-    let mut res = ExternResources::default();
-    for message in cargo_metadata::Message::parse_stream(stdout) {
-        if let Ok(message) = message {
-            match message {
-                Message::BuildScriptExecuted(BuildScript {
-                    package_id,
-                    out_dir,
-                    cfgs,
-                    env,
-                    ..
-                }) => {
-                    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.clone(), cfgs);
-                    }
-
-                    res.env.insert(package_id, env);
-                }
-                Message::CompilerArtifact(message) => {
-                    progress(format!("metadata {}", message.target.name));
-
-                    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) => {
-                    progress(message.target.name.clone());
-                }
-                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"),
-    }
-}
-
-/// Recreates the compile-time environment variables that Cargo sets.
-///
-/// Should be synced with <https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>
-fn inject_cargo_env(package: &cargo_metadata::Package, env: &mut Vec<(String, String)>) {
-    // FIXME: Missing variables:
-    // CARGO, CARGO_PKG_HOMEPAGE, CARGO_CRATE_NAME, CARGO_BIN_NAME, CARGO_BIN_EXE_<name>
-
-    let mut manifest_dir = package.manifest_path.clone();
-    manifest_dir.pop();
-    if let Some(cargo_manifest_dir) = manifest_dir.to_str() {
-        env.push(("CARGO_MANIFEST_DIR".into(), cargo_manifest_dir.into()));
-    }
-
-    env.push(("CARGO_PKG_VERSION".into(), package.version.to_string()));
-    env.push(("CARGO_PKG_VERSION_MAJOR".into(), package.version.major.to_string()));
-    env.push(("CARGO_PKG_VERSION_MINOR".into(), package.version.minor.to_string()));
-    env.push(("CARGO_PKG_VERSION_PATCH".into(), package.version.patch.to_string()));
-
-    let pre = package.version.pre.iter().map(|id| id.to_string()).format(".");
-    env.push(("CARGO_PKG_VERSION_PRE".into(), pre.to_string()));
-
-    let authors = package.authors.join(";");
-    env.push(("CARGO_PKG_AUTHORS".into(), authors));
-
-    env.push(("CARGO_PKG_NAME".into(), package.name.clone()));
-    env.push(("CARGO_PKG_DESCRIPTION".into(), package.description.clone().unwrap_or_default()));
-    //env.push(("CARGO_PKG_HOMEPAGE".into(), package.homepage.clone().unwrap_or_default()));
-    env.push(("CARGO_PKG_REPOSITORY".into(), package.repository.clone().unwrap_or_default()));
-    env.push(("CARGO_PKG_LICENSE".into(), package.license.clone().unwrap_or_default()));
-
-    let license_file =
-        package.license_file.as_ref().map(|buf| buf.display().to_string()).unwrap_or_default();
-    env.push(("CARGO_PKG_LICENSE_FILE".into(), license_file));
-}
diff --git a/crates/project_model/src/lib.rs b/crates/project_model/src/lib.rs
index aabb7a47d..525c336e6 100644
--- a/crates/project_model/src/lib.rs
+++ b/crates/project_model/src/lib.rs
@@ -5,6 +5,8 @@ mod cfg_flag;
 mod project_json;
 mod sysroot;
 mod workspace;
+mod rustc_cfg;
+mod build_data;
 
 use std::{
     fs::{read_dir, ReadDir},
diff --git a/crates/project_model/src/rustc_cfg.rs b/crates/project_model/src/rustc_cfg.rs
new file mode 100644
index 000000000..4a7bd8ae3
--- /dev/null
+++ b/crates/project_model/src/rustc_cfg.rs
@@ -0,0 +1,34 @@
+//! Runs `rustc --print cfg` to get built-in cfg flags.
+
+use std::process::Command;
+
+use crate::{cfg_flag::CfgFlag, utf8_stdout};
+
+pub(crate) fn get(target: Option<&str>) -> Vec<CfgFlag> {
+    let _p = profile::span("rustc_cfg::get");
+    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
+}
diff --git a/crates/project_model/src/workspace.rs b/crates/project_model/src/workspace.rs
index 06a0be284..bc5041e5a 100644
--- a/crates/project_model/src/workspace.rs
+++ b/crates/project_model/src/workspace.rs
@@ -16,7 +16,7 @@ use proc_macro_api::ProcMacroClient;
 use rustc_hash::{FxHashMap, FxHashSet};
 
 use crate::{
-    cargo_workspace, cfg_flag::CfgFlag, sysroot::SysrootCrate, utf8_stdout, CargoConfig,
+    cargo_workspace, cfg_flag::CfgFlag, rustc_cfg, sysroot::SysrootCrate, utf8_stdout, CargoConfig,
     CargoWorkspace, ProjectJson, ProjectManifest, Sysroot, TargetKind,
 };
 
@@ -34,15 +34,25 @@ pub struct PackageRoot {
 #[derive(Clone, Eq, PartialEq)]
 pub enum ProjectWorkspace {
     /// Project workspace was discovered by running `cargo metadata` and `rustc --print sysroot`.
-    Cargo { cargo: CargoWorkspace, sysroot: Sysroot, rustc: Option<CargoWorkspace> },
+    Cargo {
+        cargo: CargoWorkspace,
+        sysroot: Sysroot,
+        rustc: Option<CargoWorkspace>,
+        /// Holds cfg flags for the current target. We get those by running
+        /// `rustc --print cfg`.
+        ///
+        /// FIXME: make this a per-crate map, as, eg, build.rs might have a
+        /// different target.
+        rustc_cfg: Vec<CfgFlag>,
+    },
     /// Project workspace was manually specified using a `rust-project.json` file.
-    Json { project: ProjectJson, sysroot: Option<Sysroot> },
+    Json { project: ProjectJson, sysroot: Option<Sysroot>, rustc_cfg: Vec<CfgFlag> },
 }
 
 impl fmt::Debug for ProjectWorkspace {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            ProjectWorkspace::Cargo { cargo, sysroot, rustc } => f
+            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg } => f
                 .debug_struct("Cargo")
                 .field("n_packages", &cargo.packages().len())
                 .field("n_sysroot_crates", &sysroot.crates().len())
@@ -50,13 +60,15 @@ impl fmt::Debug for ProjectWorkspace {
                     "n_rustc_compiler_crates",
                     &rustc.as_ref().map_or(0, |rc| rc.packages().len()),
                 )
+                .field("rustc_cfg", rustc_cfg)
                 .finish(),
-            ProjectWorkspace::Json { project, sysroot } => {
+            ProjectWorkspace::Json { project, sysroot, rustc_cfg } => {
                 let mut debug_struct = f.debug_struct("Json");
                 debug_struct.field("n_crates", &project.n_crates());
                 if let Some(sysroot) = sysroot {
                     debug_struct.field("n_sysroot_crates", &sysroot.crates().len());
                 }
+                debug_struct.field("rustc_cfg", rustc_cfg);
                 debug_struct.finish()
             }
         }
@@ -79,7 +91,7 @@ impl ProjectWorkspace {
                 })?;
                 let project_location = project_json.parent().unwrap().to_path_buf();
                 let project_json = ProjectJson::new(&project_location, data);
-                ProjectWorkspace::load_inline(project_json)?
+                ProjectWorkspace::load_inline(project_json, config.target.as_deref())?
             }
             ProjectManifest::CargoToml(cargo_toml) => {
                 let cargo_version = utf8_stdout({
@@ -117,21 +129,24 @@ impl ProjectWorkspace {
                 } else {
                     None
                 };
-
-                ProjectWorkspace::Cargo { cargo, sysroot, rustc }
+                let rustc_cfg = rustc_cfg::get(config.target.as_deref());
+                ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg }
             }
         };
 
         Ok(res)
     }
 
-    pub fn load_inline(project_json: ProjectJson) -> Result<ProjectWorkspace> {
+    pub fn load_inline(
+        project_json: ProjectJson,
+        target: Option<&str>,
+    ) -> Result<ProjectWorkspace> {
         let sysroot = match &project_json.sysroot_src {
             Some(path) => Some(Sysroot::load(path)?),
             None => None,
         };
-
-        Ok(ProjectWorkspace::Json { project: project_json, sysroot })
+        let rustc_cfg = rustc_cfg::get(target);
+        Ok(ProjectWorkspace::Json { project: project_json, sysroot, rustc_cfg })
     }
 
     /// Returns the roots for the current `ProjectWorkspace`
@@ -139,7 +154,7 @@ impl ProjectWorkspace {
     /// the root is a member of the current workspace
     pub fn to_roots(&self) -> Vec<PackageRoot> {
         match self {
-            ProjectWorkspace::Json { project, sysroot } => project
+            ProjectWorkspace::Json { project, sysroot, rustc_cfg: _ } => project
                 .crates()
                 .map(|(_, krate)| PackageRoot {
                     is_member: krate.is_workspace_member,
@@ -156,14 +171,14 @@ impl ProjectWorkspace {
                     })
                 }))
                 .collect::<Vec<_>>(),
-            ProjectWorkspace::Cargo { cargo, sysroot, rustc } => cargo
+            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg: _ } => 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());
+                    include.extend(cargo[pkg].build_data.out_dir.clone());
 
                     let mut exclude = vec![pkg_root.join(".git")];
                     if is_member {
@@ -194,7 +209,7 @@ impl ProjectWorkspace {
     pub fn n_packages(&self) -> usize {
         match self {
             ProjectWorkspace::Json { project, .. } => project.n_crates(),
-            ProjectWorkspace::Cargo { cargo, sysroot, rustc } => {
+            ProjectWorkspace::Cargo { cargo, sysroot, rustc, .. } => {
                 let rustc_package_len = rustc.as_ref().map_or(0, |rc| rc.packages().len());
                 cargo.packages().len() + sysroot.crates().len() + rustc_package_len
             }
@@ -203,22 +218,31 @@ impl ProjectWorkspace {
 
     pub fn to_crate_graph(
         &self,
-        target: Option<&str>,
         proc_macro_client: Option<&ProcMacroClient>,
         load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
     ) -> CrateGraph {
+        let _p = profile::span("ProjectWorkspace::to_crate_graph");
         let proc_macro_loader = |path: &Path| match proc_macro_client {
             Some(client) => client.by_dylib_path(path),
             None => Vec::new(),
         };
 
         let mut crate_graph = match self {
-            ProjectWorkspace::Json { project, sysroot } => {
-                project_json_to_crate_graph(target, &proc_macro_loader, load, project, sysroot)
-            }
-            ProjectWorkspace::Cargo { cargo, sysroot, rustc } => {
-                cargo_to_crate_graph(target, &proc_macro_loader, load, cargo, sysroot, rustc)
-            }
+            ProjectWorkspace::Json { project, sysroot, rustc_cfg } => project_json_to_crate_graph(
+                rustc_cfg.clone(),
+                &proc_macro_loader,
+                load,
+                project,
+                sysroot,
+            ),
+            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg } => cargo_to_crate_graph(
+                rustc_cfg.clone(),
+                &proc_macro_loader,
+                load,
+                cargo,
+                sysroot,
+                rustc,
+            ),
         };
         if crate_graph.patch_cfg_if() {
             log::debug!("Patched std to depend on cfg-if")
@@ -230,7 +254,7 @@ impl ProjectWorkspace {
 }
 
 fn project_json_to_crate_graph(
-    target: Option<&str>,
+    rustc_cfg: Vec<CfgFlag>,
     proc_macro_loader: &dyn Fn(&Path) -> Vec<ProcMacro>,
     load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
     project: &ProjectJson,
@@ -239,9 +263,9 @@ fn project_json_to_crate_graph(
     let mut crate_graph = CrateGraph::default();
     let sysroot_deps = sysroot
         .as_ref()
-        .map(|sysroot| sysroot_to_crate_graph(&mut crate_graph, sysroot, target, load));
+        .map(|sysroot| sysroot_to_crate_graph(&mut crate_graph, sysroot, rustc_cfg.clone(), load));
 
-    let mut cfg_cache: FxHashMap<Option<&str>, Vec<CfgFlag>> = FxHashMap::default();
+    let mut cfg_cache: FxHashMap<&str, Vec<CfgFlag>> = FxHashMap::default();
     let crates: FxHashMap<CrateId, CrateId> = project
         .crates()
         .filter_map(|(crate_id, krate)| {
@@ -253,9 +277,12 @@ fn project_json_to_crate_graph(
             let env = krate.env.clone().into_iter().collect();
             let proc_macro = krate.proc_macro_dylib_path.clone().map(|it| proc_macro_loader(&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 target_cfgs = match krate.target.as_deref() {
+                Some(target) => {
+                    cfg_cache.entry(target).or_insert_with(|| rustc_cfg::get(Some(target)))
+                }
+                None => &rustc_cfg,
+            };
 
             let mut cfg_options = CfgOptions::default();
             cfg_options.extend(target_cfgs.iter().chain(krate.cfg.iter()).cloned());
@@ -292,19 +319,20 @@ fn project_json_to_crate_graph(
 }
 
 fn cargo_to_crate_graph(
-    target: Option<&str>,
+    rustc_cfg: Vec<CfgFlag>,
     proc_macro_loader: &dyn Fn(&Path) -> Vec<ProcMacro>,
     load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
     cargo: &CargoWorkspace,
     sysroot: &Sysroot,
     rustc: &Option<CargoWorkspace>,
 ) -> CrateGraph {
+    let _p = profile::span("cargo_to_crate_graph");
     let mut crate_graph = CrateGraph::default();
     let (public_deps, libproc_macro) =
-        sysroot_to_crate_graph(&mut crate_graph, sysroot, target, load);
+        sysroot_to_crate_graph(&mut crate_graph, sysroot, rustc_cfg.clone(), load);
 
     let mut cfg_options = CfgOptions::default();
-    cfg_options.extend(get_rustc_cfg_options(target));
+    cfg_options.extend(rustc_cfg);
 
     let mut pkg_to_lib_crate = FxHashMap::default();
 
@@ -453,26 +481,24 @@ fn add_target_crate_root(
     let edition = pkg.edition;
     let cfg_options = {
         let mut opts = cfg_options.clone();
-        for feature in pkg.features.iter() {
+        for feature in pkg.active_features.iter() {
             opts.insert_key_value("feature".into(), feature.into());
         }
-        opts.extend(pkg.cfgs.iter().cloned());
+        opts.extend(pkg.build_data.cfgs.iter().cloned());
         opts
     };
 
     let mut env = Env::default();
-    for (k, v) in &pkg.envs {
+    for (k, v) in &pkg.build_data.envs {
         env.set(k, v.clone());
     }
-    if let Some(out_dir) = &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 =
-        pkg.proc_macro_dylib_path.as_ref().map(|it| proc_macro_loader(&it)).unwrap_or_default();
+    let proc_macro = pkg
+        .build_data
+        .proc_macro_dylib_path
+        .as_ref()
+        .map(|it| proc_macro_loader(&it))
+        .unwrap_or_default();
 
     let display_name = CrateDisplayName::from_canonical_name(pkg.name.clone());
     let crate_id = crate_graph.add_crate_root(
@@ -490,11 +516,12 @@ fn add_target_crate_root(
 fn sysroot_to_crate_graph(
     crate_graph: &mut CrateGraph,
     sysroot: &Sysroot,
-    target: Option<&str>,
+    rustc_cfg: Vec<CfgFlag>,
     load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
 ) -> (Vec<(CrateName, CrateId)>, Option<CrateId>) {
+    let _p = profile::span("sysroot_to_crate_graph");
     let mut cfg_options = CfgOptions::default();
-    cfg_options.extend(get_rustc_cfg_options(target));
+    cfg_options.extend(rustc_cfg);
     let sysroot_crates: FxHashMap<SysrootCrate, CrateId> = sysroot
         .crates()
         .filter_map(|krate| {
@@ -533,34 +560,6 @@ fn sysroot_to_crate_graph(
     (public_deps, libproc_macro)
 }
 
-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 add_dep(graph: &mut CrateGraph, from: CrateId, name: CrateName, to: CrateId) {
     if let Err(err) = graph.add_dep(from, name, to) {
         log::error!("{}", err)