Experiment: Create timing report.

Cargo.toml

@@ -37,6 +37,7 @@ git2-curl = "0.11.0"
 glob = "0.3.0"
 hex = "0.3"
 home = "0.5"
+humantime = "1.2.0"
 ignore = "0.4.7"
 lazy_static = "1.2.0"
 jobserver = "0.1.13"

src/bin/cargo/cli.rs

@@ -36,6 +36,7 @@ Available unstable (nightly-only) flags:
     -Z config-profile   -- Read profiles from .cargo/config files
     -Z install-upgrade  -- `cargo install` will upgrade instead of failing
     -Z cache-messages   -- Cache compiler messages
+    -Z timings          -- Display concurrency information
 
 Run with 'cargo -Z [FLAG] [SUBCOMMAND]'"
         );

src/cargo/core/compiler/context/mod.rs

@@ -129,7 +129,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
         export_dir: Option<PathBuf>,
         exec: &Arc<dyn Executor>,
     ) -> CargoResult<Compilation<'cfg>> {
-        let mut queue = JobQueue::new(self.bcx);
+        let mut queue = JobQueue::new(self.bcx, units);
         let mut plan = BuildPlan::new();
         let build_plan = self.bcx.build_config.build_plan;
         self.prepare_units(export_dir, units)?;

src/cargo/core/compiler/job_queue.rs

@@ -14,6 +14,7 @@ use super::job::{
     Freshness::{self, Dirty, Fresh},
     Job,
 };
+use super::timings::Timings;
 use super::{BuildContext, BuildPlan, CompileMode, Context, Unit};
 use crate::core::{PackageId, TargetKind};
 use crate::handle_error;
@@ -39,6 +40,7 @@ pub struct JobQueue<'a, 'cfg> {
     is_release: bool,
     progress: Progress<'cfg>,
     next_id: u32,
+    timings: Option<Timings<'a, 'cfg>>,
 }
 
 pub struct JobState<'a> {
@@ -80,7 +82,7 @@ enum Artifact {
 }
 
 enum Message {
-    Run(String),
+    Run(u32, String),
     BuildPlanMsg(String, ProcessBuilder, Arc<Vec<OutputFile>>),
     Stdout(String),
     Stderr(String),
@@ -91,7 +93,7 @@ enum Message {
 
 impl<'a> JobState<'a> {
     pub fn running(&self, cmd: &ProcessBuilder) {
-        let _ = self.tx.send(Message::Run(cmd.to_string()));
+        let _ = self.tx.send(Message::Run(self.id, cmd.to_string()));
     }
 
     pub fn build_plan(
@@ -119,7 +121,6 @@ impl<'a> JobState<'a> {
     /// This should only be called once because a metadata file can only be
     /// produced once!
     pub fn rmeta_produced(&self) {
-        assert!(self.rmeta_required.get());
         self.rmeta_required.set(false);
         let _ = self
             .tx
@@ -128,9 +129,13 @@ impl<'a> JobState<'a> {
 }
 
 impl<'a, 'cfg> JobQueue<'a, 'cfg> {
-    pub fn new(bcx: &BuildContext<'a, 'cfg>) -> JobQueue<'a, 'cfg> {
+    pub fn new(bcx: &BuildContext<'a, 'cfg>, root_units: &[Unit<'a>]) -> JobQueue<'a, 'cfg> {
         let (tx, rx) = channel();
         let progress = Progress::with_style("Building", ProgressStyle::Ratio, bcx.config);
+        let timings = match bcx.config.cli_unstable().timings {
+            Some(..) => Some(Timings::new(bcx, root_units)),
+            None => None,
+        };
         JobQueue {
             queue: DependencyQueue::new(),
             tx,
@@ -142,6 +147,7 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
             is_release: bcx.build_config.release,
             progress,
             next_id: 0,
+            timings,
         }
     }
 
@@ -316,6 +322,10 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
             // to the jobserver itself.
             tokens.truncate(self.active.len() - 1);
 
+            if let Some(t) = &mut self.timings {
+                t.mark_concurrency(self.active.len(), queue.len(), self.queue.len());
+            }
+
             // Drain all events at once to avoid displaying the progress bar
             // unnecessarily.
             let events: Vec<_> = self.rx.try_iter().collect();
@@ -328,18 +338,20 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
 
             for event in events {
                 match event {
-                    Message::Run(cmd) => {
+                    Message::Run(id, cmd) => {
                         cx.bcx
                             .config
                             .shell()
                             .verbose(|c| c.status("Running", &cmd))?;
+                        if let Some(t) = &mut self.timings {
+                            t.unit_start(id, self.active[&id]);
+                        }
                     }
                     Message::BuildPlanMsg(module_name, cmd, filenames) => {
                         plan.update(&module_name, &cmd, &filenames)?;
                     }
                     Message::Stdout(out) => {
-                        self.progress.clear();
-                        println!("{}", out);
+                        cx.bcx.config.shell().stdout_println(out);
                     }
                     Message::Stderr(err) => {
                         let mut shell = cx.bcx.config.shell();
@@ -367,7 +379,7 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
                         };
                         info!("end ({:?}): {:?}", unit, result);
                         match result {
-                            Ok(()) => self.finish(&unit, artifact, cx)?,
+                            Ok(()) => self.finish(id, &unit, artifact, cx)?,
                             Err(e) => {
                                 let msg = "The following warnings were emitted during compilation:";
                                 self.emit_warnings(Some(msg), &unit, cx)?;
@@ -425,6 +437,9 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
             if !cx.bcx.build_config.build_plan {
                 cx.bcx.config.shell().status("Finished", message)?;
             }
+            if let Some(t) = &mut self.timings {
+                t.finished()?;
+            }
             Ok(())
         } else {
             debug!("queue: {:#?}", self.queue);
@@ -519,8 +534,16 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
         }
 
         match fresh {
-            Freshness::Fresh => doit(),
+            Freshness::Fresh => {
+                if let Some(t) = &mut self.timings {
+                    t.add_fresh();
+                }
+                doit()
+            }
             Freshness::Dirty => {
+                if let Some(t) = &mut self.timings {
+                    t.add_dirty();
+                }
                 scope.spawn(move |_| doit());
             }
         }
@@ -558,14 +581,21 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
 
     fn finish(
         &mut self,
+        id: u32,
         unit: &Unit<'a>,
         artifact: Artifact,
         cx: &mut Context<'_, '_>,
     ) -> CargoResult<()> {
         if unit.mode.is_run_custom_build() && cx.bcx.show_warnings(unit.pkg.package_id()) {
             self.emit_warnings(None, unit, cx)?;
         }
-        self.queue.finish(unit, &artifact);
+        let unlocked = self.queue.finish(unit, &artifact);
+        if let Some(t) = &mut self.timings {
+            match artifact {
+                Artifact::All => t.unit_finished(id, unlocked),
+                Artifact::Metadata => t.unit_rmeta_finished(id, unlocked),
+            }
+        }
         Ok(())
     }
 

src/cargo/core/compiler/mod.rs

@@ -11,20 +11,20 @@ mod layout;
 mod links;
 mod output_depinfo;
 pub mod standard_lib;
+mod timings;
 mod unit;
 pub mod unit_dependencies;
 
 use std::env;
 use std::ffi::{OsStr, OsString};
 use std::fs::{self, File};
 use std::io::Write;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::sync::Arc;
 
 use failure::Error;
 use lazycell::LazyCell;
 use log::debug;
-use same_file::is_same_file;
 use serde::Serialize;
 
 pub use self::build_config::{BuildConfig, CompileMode, MessageFormat};
@@ -442,12 +442,12 @@ fn link_targets<'a, 'cfg>(
                 }
             };
             destinations.push(dst.clone());
-            hardlink_or_copy(src, dst)?;
+            paths::link_or_copy(src, dst)?;
             if let Some(ref path) = output.export_path {
                 let export_dir = export_dir.as_ref().unwrap();
                 paths::create_dir_all(export_dir)?;
 
-                hardlink_or_copy(src, path)?;
+                paths::link_or_copy(src, path)?;
             }
         }
 
@@ -476,54 +476,6 @@ fn link_targets<'a, 'cfg>(
     }))
 }
 
-/// Hardlink (file) or symlink (dir) src to dst if possible, otherwise copy it.
-fn hardlink_or_copy(src: &Path, dst: &Path) -> CargoResult<()> {
-    debug!("linking {} to {}", src.display(), dst.display());
-    if is_same_file(src, dst).unwrap_or(false) {
-        return Ok(());
-    }
-
-    // NB: we can't use dst.exists(), as if dst is a broken symlink,
-    // dst.exists() will return false. This is problematic, as we still need to
-    // unlink dst in this case. symlink_metadata(dst).is_ok() will tell us
-    // whether dst exists *without* following symlinks, which is what we want.
-    if fs::symlink_metadata(dst).is_ok() {
-        paths::remove_file(&dst)?;
-    }
-
-    let link_result = if src.is_dir() {
-        #[cfg(target_os = "redox")]
-        use std::os::redox::fs::symlink;
-        #[cfg(unix)]
-        use std::os::unix::fs::symlink;
-        #[cfg(windows)]
-        use std::os::windows::fs::symlink_dir as symlink;
-
-        let dst_dir = dst.parent().unwrap();
-        let src = if src.starts_with(dst_dir) {
-            src.strip_prefix(dst_dir).unwrap()
-        } else {
-            src
-        };
-        symlink(src, dst)
-    } else {
-        fs::hard_link(src, dst)
-    };
-    link_result
-        .or_else(|err| {
-            debug!("link failed {}. falling back to fs::copy", err);
-            fs::copy(src, dst).map(|_| ())
-        })
-        .chain_err(|| {
-            format!(
-                "failed to link or copy `{}` to `{}`",
-                src.display(),
-                dst.display()
-            )
-        })?;
-    Ok(())
-}
-
 // For all plugin dependencies, add their -L paths (now calculated and present
 // in `build_script_outputs`) to the dynamic library load path for the command
 // to execute.
@@ -746,10 +698,11 @@ fn add_error_format_and_color(
     // prettily, and then when parsing JSON messages from rustc we need to
     // internally understand that we should extract the `rendered` field and
     // present it if we can.
-    if cx.bcx.build_config.cache_messages() || pipelined {
+    let wants_artifacts = pipelined || cx.bcx.config.cli_unstable().timings.is_some();
+    if cx.bcx.build_config.cache_messages() || wants_artifacts {
         cmd.arg("--error-format=json");
         let mut json = String::from("--json=diagnostic-rendered-ansi");
-        if pipelined {
+        if wants_artifacts {
             json.push_str(",artifacts");
         }
         match cx.bcx.build_config.message_format {
@@ -1123,7 +1076,8 @@ struct OutputOptions {
 
 impl OutputOptions {
     fn new<'a>(cx: &Context<'a, '_>, unit: &Unit<'a>) -> OutputOptions {
-        let look_for_metadata_directive = cx.rmeta_required(unit);
+        let look_for_metadata_directive =
+            cx.rmeta_required(unit) || cx.bcx.config.cli_unstable().timings.is_some();
         let color = cx.bcx.config.shell().supports_color();
         let cache_cell = if cx.bcx.build_config.cache_messages() {
             let path = cx.files().message_cache_path(unit);