7 files changed, 111 insertions, 300 deletions

diff --git a/crates/rust-analyzer/src/benchmarks.rs b/crates/rust-analyzer/src/benchmarks.rs
new file mode 100644
index 000000000..a6f997af8
--- /dev/null
+++ b/crates/rust-analyzer/src/benchmarks.rs
@@ -0,0 +1,69 @@
+//! Fully integrated benchmarks for rust-analyzer, which load real cargo
+//! projects.
+//!
+//! The benchmark here is used to debug specific performance regressions. If you
+//! notice that, eg, completion is slow in some specific case, you can  modify
+//! code here exercise this specific completion, and thus have a fast
+//! edit/compile/test cycle.
+//!
+//! Note that "Rust Analyzer: Run" action does not allow running a single test
+//! in release mode in VS Code. There's however "Rust Analyzer: Copy Run Command Line"
+//! which you can use to paste the command in terminal and add `--release` manually.
+
+use std::sync::Arc;
+
+use ide::Change;
+use test_utils::project_root;
+use vfs::{AbsPathBuf, VfsPath};
+
+use crate::cli::load_cargo::{load_workspace_at, LoadCargoConfig};
+
+#[test]
+fn benchmark_integrated_highlighting() {
+    // Don't run slow benchmark by default
+    if true {
+        return;
+    }
+
+    // Load rust-analyzer itself.
+    let workspace_to_load = project_root();
+    let file = "./crates/ide_db/src/apply_change.rs";
+
+    let cargo_config = Default::default();
+    let load_cargo_config =
+        LoadCargoConfig { load_out_dirs_from_check: true, with_proc_macro: false };
+
+    let (mut host, vfs, _proc_macro) = {
+        let _it = stdx::timeit("workspace loading");
+        load_workspace_at(&workspace_to_load, &cargo_config, &load_cargo_config, &|_| {}).unwrap()
+    };
+
+    let file_id = {
+        let file = workspace_to_load.join(file);
+        let path = VfsPath::from(AbsPathBuf::assert(file));
+        vfs.file_id(&path).unwrap_or_else(|| panic!("can't find virtual file for {}", path))
+    };
+
+    {
+        let _it = stdx::timeit("initial");
+        let analysis = host.analysis();
+        analysis.highlight_as_html(file_id, false).unwrap();
+    }
+
+    profile::init_from("*>100");
+
+    {
+        let _it = stdx::timeit("change");
+        let mut text = host.analysis().file_text(file_id).unwrap().to_string();
+        text.push_str("\npub fn _dummy() {}\n");
+        let mut change = Change::new();
+        change.change_file(file_id, Some(Arc::new(text)));
+        host.apply_change(change);
+    }
+
+    {
+        let _it = stdx::timeit("after change");
+        let analysis = host.analysis();
+        analysis.highlight_as_html(file_id, false).unwrap();
+    }
+}
diff --git a/crates/rust-analyzer/src/bin/flags.rs b/crates/rust-analyzer/src/bin/flags.rs
index d8987633d..b05fc00b9 100644
--- a/crates/rust-analyzer/src/bin/flags.rs
+++ b/crates/rust-analyzer/src/bin/flags.rs
@@ -1,10 +1,9 @@
 //! Grammar for the command-line arguments.
 #![allow(unreachable_pub)]
-use std::{env, path::PathBuf};
+use std::path::PathBuf;
 
 use ide_ssr::{SsrPattern, SsrRule};
-use rust_analyzer::cli::{BenchWhat, Position, Verbosity};
-use vfs::AbsPathBuf;
+use rust_analyzer::cli::Verbosity;
 
 xflags::xflags! {
     src "./src/bin/flags.rs"
@@ -74,27 +73,6 @@ xflags::xflags! {
             optional --with-proc-macro
         }
 
-        /// Benchmark specific analysis operation
-        cmd analysis-bench
-            /// Directory with Cargo.toml.
-            required path: PathBuf
-        {
-            /// Collect memory usage statistics.
-            optional --memory-usage
-
-            /// Compute syntax highlighting for this file
-            optional --highlight path: PathBuf
-            /// Compute completions at file:line:column location.
-            optional --complete location: Position
-            /// Compute goto definition at file:line:column location.
-            optional --goto-def location: Position
-
-            /// Load OUT_DIR values by running `cargo check` before analysis.
-            optional --load-output-dirs
-            /// Use proc-macro-srv for proc-macro expanding.
-            optional --with-proc-macro
-        }
-
         cmd diagnostics
             /// Directory with Cargo.toml.
             required path: PathBuf
@@ -142,7 +120,6 @@ pub enum RustAnalyzerCmd {
     Symbols(Symbols),
     Highlight(Highlight),
     AnalysisStats(AnalysisStats),
-    AnalysisBench(AnalysisBench),
     Diagnostics(Diagnostics),
     Ssr(Ssr),
     Search(Search),
@@ -184,18 +161,6 @@ pub struct AnalysisStats {
 }
 
 #[derive(Debug)]
-pub struct AnalysisBench {
-    pub path: PathBuf,
-
-    pub memory_usage: bool,
-    pub highlight: Option<PathBuf>,
-    pub complete: Option<Position>,
-    pub goto_def: Option<Position>,
-    pub load_output_dirs: bool,
-    pub with_proc_macro: bool,
-}
-
-#[derive(Debug)]
 pub struct Diagnostics {
     pub path: PathBuf,
 
@@ -239,17 +204,3 @@ impl RustAnalyzer {
         }
     }
 }
-
-impl AnalysisBench {
-    pub(crate) fn what(&self) -> BenchWhat {
-        match (&self.highlight, &self.complete, &self.goto_def) {
-            (Some(path), None, None) => {
-                let path = env::current_dir().unwrap().join(path);
-                BenchWhat::Highlight { path: AbsPathBuf::assert(path) }
-            }
-            (None, Some(position), None) => BenchWhat::Complete(position.clone()),
-            (None, None, Some(position)) => BenchWhat::GotoDef(position.clone()),
-            _ => panic!("exactly one of  `--highlight`, `--complete` or `--goto-def` must be set"),
-        }
-    }
-}
diff --git a/crates/rust-analyzer/src/bin/main.rs b/crates/rust-analyzer/src/bin/main.rs
index a0b611bff..ae99eefe3 100644
--- a/crates/rust-analyzer/src/bin/main.rs
+++ b/crates/rust-analyzer/src/bin/main.rs
@@ -9,7 +9,7 @@ use std::{convert::TryFrom, env, fs, path::Path, process};
 use lsp_server::Connection;
 use project_model::ProjectManifest;
 use rust_analyzer::{
-    cli::{self, AnalysisStatsCmd, BenchCmd},
+    cli::{self, AnalysisStatsCmd},
     config::Config,
     from_json,
     lsp_ext::supports_utf8,
@@ -80,17 +80,6 @@ fn try_main() -> Result<()> {
             with_proc_macro: cmd.with_proc_macro,
         }
         .run(verbosity)?,
-        flags::RustAnalyzerCmd::AnalysisBench(cmd) => {
-            let what = cmd.what();
-            BenchCmd {
-                memory_usage: cmd.memory_usage,
-                path: cmd.path,
-                load_output_dirs: cmd.load_output_dirs,
-                with_proc_macro: cmd.with_proc_macro,
-                what,
-            }
-            .run(verbosity)?
-        }
 
         flags::RustAnalyzerCmd::Diagnostics(cmd) => {
             cli::diagnostics(&cmd.path, cmd.load_output_dirs, cmd.with_proc_macro)?
diff --git a/crates/rust-analyzer/src/cli.rs b/crates/rust-analyzer/src/cli.rs
index ed732eb38..76b666dc2 100644
--- a/crates/rust-analyzer/src/cli.rs
+++ b/crates/rust-analyzer/src/cli.rs
@@ -1,8 +1,7 @@
 //! Various batch processing tasks, intended primarily for debugging.
 
-mod load_cargo;
+pub(crate) mod load_cargo;
 mod analysis_stats;
-mod analysis_bench;
 mod diagnostics;
 mod progress_report;
 mod ssr;
@@ -15,7 +14,6 @@ use syntax::{AstNode, SourceFile};
 use vfs::Vfs;
 
 pub use self::{
-    analysis_bench::{BenchCmd, BenchWhat, Position},
     analysis_stats::AnalysisStatsCmd,
     diagnostics::diagnostics,
     load_cargo::{load_workspace, load_workspace_at, LoadCargoConfig},
diff --git a/crates/rust-analyzer/src/cli/analysis_bench.rs b/crates/rust-analyzer/src/cli/analysis_bench.rs
deleted file mode 100644
index 49994824f..000000000
--- a/crates/rust-analyzer/src/cli/analysis_bench.rs
+++ /dev/null
@@ -1,196 +0,0 @@
-//! Benchmark operations like highlighting or goto definition.
-
-use std::{env, path::PathBuf, str::FromStr, sync::Arc, time::Instant};
-
-use anyhow::{bail, format_err, Result};
-use hir::PrefixKind;
-use ide::{
-    Analysis, AnalysisHost, Change, CompletionConfig, DiagnosticsConfig, FilePosition, LineCol,
-};
-use ide_db::{
-    base_db::{
-        salsa::{Database, Durability},
-        FileId,
-    },
-    helpers::{insert_use::InsertUseConfig, SnippetCap},
-};
-use vfs::AbsPathBuf;
-
-use crate::cli::{
-    load_cargo::{load_workspace_at, LoadCargoConfig},
-    print_memory_usage, Verbosity,
-};
-
-pub struct BenchCmd {
-    pub path: PathBuf,
-    pub what: BenchWhat,
-    pub memory_usage: bool,
-    pub load_output_dirs: bool,
-    pub with_proc_macro: bool,
-}
-
-pub enum BenchWhat {
-    Highlight { path: AbsPathBuf },
-    Complete(Position),
-    GotoDef(Position),
-}
-
-#[derive(Debug, Clone)]
-pub struct Position {
-    pub path: AbsPathBuf,
-    pub line: u32,
-    pub column: u32,
-}
-
-impl FromStr for Position {
-    type Err = anyhow::Error;
-    fn from_str(s: &str) -> Result<Self> {
-        let mut split = s.rsplitn(3, ':');
-        match (split.next(), split.next(), split.next()) {
-            (Some(column), Some(line), Some(path)) => {
-                let path = env::current_dir().unwrap().join(path);
-                let path = AbsPathBuf::assert(path);
-                Ok(Position { path, line: line.parse()?, column: column.parse()? })
-            }
-            _ => bail!("position should be in file:line:column format: {:?}", s),
-        }
-    }
-}
-
-impl BenchCmd {
-    pub fn run(self, verbosity: Verbosity) -> Result<()> {
-        profile::init();
-
-        let start = Instant::now();
-        eprint!("loading: ");
-
-        let cargo_config = Default::default();
-        let load_cargo_config = LoadCargoConfig {
-            load_out_dirs_from_check: self.load_output_dirs,
-            with_proc_macro: self.with_proc_macro,
-        };
-        let (mut host, vfs, _proc_macro) =
-            load_workspace_at(&self.path, &cargo_config, &load_cargo_config, &|_| {})?;
-        eprintln!("{:?}\n", start.elapsed());
-
-        let file_id = {
-            let path = match &self.what {
-                BenchWhat::Highlight { path } => path,
-                BenchWhat::Complete(pos) | BenchWhat::GotoDef(pos) => &pos.path,
-            };
-            let path = path.clone().into();
-            vfs.file_id(&path).ok_or_else(|| format_err!("Can't find {}", path))?
-        };
-
-        match &self.what {
-            BenchWhat::Highlight { .. } => {
-                let res = do_work(&mut host, file_id, |analysis| {
-                    analysis.diagnostics(&DiagnosticsConfig::default(), file_id).unwrap();
-                    analysis.highlight_as_html(file_id, false).unwrap()
-                });
-                if verbosity.is_verbose() {
-                    println!("\n{}", res);
-                }
-            }
-            BenchWhat::Complete(pos) | BenchWhat::GotoDef(pos) => {
-                let is_completion = matches!(self.what, BenchWhat::Complete(..));
-
-                let offset = host
-                    .analysis()
-                    .file_line_index(file_id)?
-                    .offset(LineCol { line: pos.line - 1, col: pos.column });
-                let file_position = FilePosition { file_id, offset };
-
-                if is_completion {
-                    let options = CompletionConfig {
-                        enable_postfix_completions: true,
-                        enable_imports_on_the_fly: true,
-                        add_call_parenthesis: true,
-                        add_call_argument_snippets: true,
-                        snippet_cap: SnippetCap::new(true),
-                        insert_use: InsertUseConfig {
-                            merge: None,
-                            prefix_kind: PrefixKind::Plain,
-                            group: true,
-                        },
-                    };
-                    let res = do_work(&mut host, file_id, |analysis| {
-                        analysis.completions(&options, file_position)
-                    });
-                    if verbosity.is_verbose() {
-                        println!("\n{:#?}", res);
-                    }
-                } else {
-                    let res = do_work(&mut host, file_id, |analysis| {
-                        analysis.goto_definition(file_position)
-                    });
-                    if verbosity.is_verbose() {
-                        println!("\n{:#?}", res);
-                    }
-                }
-            }
-        }
-
-        if self.memory_usage {
-            print_memory_usage(host, vfs);
-        }
-
-        Ok(())
-    }
-}
-
-fn do_work<F: Fn(&Analysis) -> T, T>(host: &mut AnalysisHost, file_id: FileId, work: F) -> T {
-    {
-        let start = Instant::now();
-        eprint!("from scratch:   ");
-        work(&host.analysis());
-        eprintln!("{:?}", start.elapsed());
-    }
-    {
-        let start = Instant::now();
-        eprint!("no change:      ");
-        work(&host.analysis());
-        eprintln!("{:?}", start.elapsed());
-    }
-    {
-        let start = Instant::now();
-        eprint!("trivial change: ");
-        host.raw_database_mut().salsa_runtime_mut().synthetic_write(Durability::LOW);
-        work(&host.analysis());
-        eprintln!("{:?}", start.elapsed());
-    }
-    {
-        let start = Instant::now();
-        eprint!("comment change: ");
-        {
-            let mut text = host.analysis().file_text(file_id).unwrap().to_string();
-            text.push_str("\n/* Hello world */\n");
-            let mut change = Change::new();
-            change.change_file(file_id, Some(Arc::new(text)));
-            host.apply_change(change);
-        }
-        work(&host.analysis());
-        eprintln!("{:?}", start.elapsed());
-    }
-    {
-        let start = Instant::now();
-        eprint!("item change:    ");
-        {
-            let mut text = host.analysis().file_text(file_id).unwrap().to_string();
-            text.push_str("\npub fn _dummy() {}\n");
-            let mut change = Change::new();
-            change.change_file(file_id, Some(Arc::new(text)));
-            host.apply_change(change);
-        }
-        work(&host.analysis());
-        eprintln!("{:?}", start.elapsed());
-    }
-    {
-        let start = Instant::now();
-        eprint!("const change:   ");
-        host.raw_database_mut().salsa_runtime_mut().synthetic_write(Durability::HIGH);
-        let res = work(&host.analysis());
-        eprintln!("{:?}", start.elapsed());
-        res
-    }
-}
diff --git a/crates/rust-analyzer/src/lib.rs b/crates/rust-analyzer/src/lib.rs
index 8b874239c..d9a5030a0 100644
--- a/crates/rust-analyzer/src/lib.rs
+++ b/crates/rust-analyzer/src/lib.rs
@@ -39,6 +39,9 @@ mod op_queue;
 pub mod lsp_ext;
 pub mod config;
 
+#[cfg(test)]
+mod benchmarks;
+
 use serde::de::DeserializeOwned;
 use std::fmt;
 
diff --git a/docs/dev/README.md b/docs/dev/README.md
index dcbab1a1d..eab21a765 100644
--- a/docs/dev/README.md
+++ b/docs/dev/README.md
@@ -1,7 +1,7 @@
 # Contributing Quick Start
 
-Rust Analyzer is an ordinary Rust project, which is organized as a Cargo
-workspace, builds on stable and doesn't depend on C libraries. So, just
+Rust Analyzer is an ordinary Rust project, which is organized as a Cargo workspace, builds on stable and doesn't depend on C libraries.
+So, just
 
 ```
 $ cargo test
@@ -13,9 +13,8 @@ To learn more about how rust-analyzer works, see [./architecture.md](./architect
 It also explains the high-level layout of the source code.
 Do skim through that document.
 
-We also publish rustdoc docs to pages:
-
-https://rust-analyzer.github.io/rust-analyzer/ide/
+We also publish rustdoc docs to pages: https://rust-analyzer.github.io/rust-analyzer/ide/.
+Note though, that internal documentation is very incomplete.
 
 Various organizational and process issues are discussed in this document.
 
@@ -49,21 +48,28 @@ https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0
   Also a kind of fun.
   These issues should generally include a link to a Zulip discussion thread.
 
-# CI
+# Code Style & Review Process
+
+Do see [./style.md](./style.md).
 
-We use GitHub Actions for CI. Most of the things, including formatting, are checked by
-`cargo test` so, if `cargo test` passes locally, that's a good sign that CI will
-be green as well. The only exception is that some long-running tests are skipped locally by default.
+# Cookbook
+
+## CI
+
+We use GitHub Actions for CI.
+Most of the things, including formatting, are checked by `cargo test`.
+If `cargo test` passes locally, that's a good sign that CI will be green as well.
+The only exception is that some long-running tests are skipped locally by default.
 Use `env RUN_SLOW_TESTS=1 cargo test` to run the full suite.
 
 We use bors-ng to enforce the [not rocket science](https://graydon2.dreamwidth.org/1597.html) rule.
 
-# Launching rust-analyzer
+## Launching rust-analyzer
 
 Debugging the language server can be tricky.
 LSP is rather chatty, so driving it from the command line is not really feasible, driving it via VS Code requires interacting with two processes.
 
-For this reason, the best way to see how rust-analyzer works is to find a relevant test and execute it.
+For this reason, the best way to see how rust-analyzer works is to **find a relevant test and execute it**.
 VS Code & Emacs include an action for running a single test.
 
 Launching a VS Code instance with a locally built language server is also possible.
@@ -107,12 +113,7 @@ cd editors/code
 npm ci
 npm run lint
 ```
-
-# Code Style & Review Process
-
-Do see [./style.md](./style.md).
-
-# How to ...
+## How to ...
 
 * ... add an assist? [#7535](https://github.com/rust-analyzer/rust-analyzer/pull/7535)
 * ... add a new protocol extension? [#4569](https://github.com/rust-analyzer/rust-analyzer/pull/4569)
@@ -120,18 +121,17 @@ Do see [./style.md](./style.md).
 * ... add a new completion? [#6964](https://github.com/rust-analyzer/rust-analyzer/pull/6964)
 * ... allow new syntax in the parser? [#7338](https://github.com/rust-analyzer/rust-analyzer/pull/7338)
 
-# Logging
+## Logging
 
-Logging is done by both rust-analyzer and VS Code, so it might be tricky to
-figure out where logs go.
+Logging is done by both rust-analyzer and VS Code, so it might be tricky to figure out where logs go.
 
-Inside rust-analyzer, we use the standard `log` crate for logging, and
-`env_logger` for logging frontend. By default, log goes to stderr, but the
-stderr itself is processed by VS Code.
+Inside rust-analyzer, we use the standard `log` crate for logging, and `env_logger` for logging frontend.
+By default, log goes to stderr, but the stderr itself is processed by VS Code.
+`--log-file <PATH>` CLI argument allows logging to file.
 
-To see stderr in the running VS Code instance, go to the "Output" tab of the
-panel and select `rust-analyzer`. This shows `eprintln!` as well. Note that
-`stdout` is used for the actual protocol, so `println!` will break things.
+To see stderr in the running VS Code instance, go to the "Output" tab of the panel and select `rust-analyzer`.
+This shows `eprintln!` as well.
+Note that `stdout` is used for the actual protocol, so `println!` will break things.
 
 To log all communication between the server and the client, there are two choices:
 
@@ -139,17 +139,12 @@ To log all communication between the server and the client, there are two choice
   ```
   env RA_LOG=lsp_server=debug code .
   ```
+* You can log on the client side, by enabling `"rust-analyzer.trace.server": "verbose"` workspace setting.
+  These logs are shown in a separate tab in the output and could be used with LSP inspector.
+  Kudos to [@DJMcNab](https://github.com/DJMcNab) for setting this awesome infra up!
 
-  By default, logs go to stderr, `--log-file <PATH>` CLI argument overrides
-  that.
 
-* You can log on the client side, by enabling `"rust-analyzer.trace.server":
-  "verbose"` workspace setting. These logs are shown in a separate tab in the
-  output and could be used with LSP inspector. Kudos to
-  [@DJMcNab](https://github.com/DJMcNab) for setting this awesome infra up!
-
-
-There are also two VS Code commands which might be of interest:
+There are also several VS Code commands which might be of interest:
 
 * `Rust Analyzer: Status` shows some memory-usage statistics.
 
@@ -167,7 +162,7 @@ There are also two VS Code commands which might be of interest:
 
   ![demo](https://user-images.githubusercontent.com/36276403/78225773-6636a480-74d3-11ea-9d9f-1c9d42da03b0.png)
 
-# Profiling
+## Profiling
 
 We have a built-in hierarchical profiler, you can enable it by using `RA_PROFILE` env-var:
 
@@ -195,7 +190,9 @@ $ cargo run --release -p rust-analyzer -- analysis-bench ../chalk/ --highlight .
 $ cargo run --release -p rust-analyzer -- analysis-bench ../chalk/ --complete ../chalk/chalk-engine/src/logic.rs:94:0
 ```
 
-# Release Process
+Look for `fn benchmark_xxx` tests for a quick way to reproduce performance problems.
+
+## Release Process
 
 Release process is handled by `release`, `dist` and `promote` xtasks, `release` being the main one.
 
@@ -232,7 +229,7 @@ Make sure to remove the new changelog post created when running `cargo xtask rel
 We release "nightly" every night automatically and promote the latest nightly to "stable" manually, every week.
 We don't do "patch" releases, unless something truly egregious comes up.
 
-# Permissions
+## Permissions
 
 There are three sets of people with extra permissions: