Merge #5244

5244: Add a command to compute memory usage statistics r=matklad a=jonas-schievink

This allows inspecting memory usage on a live rust-analyzer instance after it has been used interactively.

This will only work with `--features jemalloc`, so maybe it should print something more useful when that's not available? Right now it will just print 0 Bytes for every query.

Co-authored-by: Jonas Schievink <[email protected]>

4 files changed, 30 insertions, 1 deletions

diff --git a/crates/ra_ide_db/src/change.rs b/crates/ra_ide_db/src/change.rs
index d8da3f949..84c6f40ff 100644
--- a/crates/ra_ide_db/src/change.rs
+++ b/crates/ra_ide_db/src/change.rs
@@ -164,6 +164,15 @@ impl RootDatabase {
         hir::db::BodyQuery.in_db(self).sweep(sweep);
     }
 
+    // Feature: Memory Usage
+    //
+    // Clears rust-analyzer's internal database and prints memory usage statistics.
+    //
+    // |===
+    // | Editor  | Action Name
+    //
+    // | VS Code | **Rust Analyzer: Memory Usage (Clears Database)**
+    // |===
     pub fn per_query_memory_usage(&mut self) -> Vec<(String, Bytes)> {
         let mut acc: Vec<(String, Bytes)> = vec![];
         let sweep = SweepStrategy::default().discard_values().sweep_all_revisions();
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index cc83a1406..f374334fe 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -32,7 +32,7 @@ use crate::{
     cargo_target_spec::CargoTargetSpec,
     config::RustfmtConfig,
     from_json, from_proto,
-    global_state::GlobalStateSnapshot,
+    global_state::{GlobalState, GlobalStateSnapshot},
     lsp_ext::{self, InlayHint, InlayHintsParams},
     to_proto, LspError, Result,
 };
@@ -62,6 +62,17 @@ pub(crate) fn handle_analyzer_status(snap: GlobalStateSnapshot, _: ()) -> Result
     Ok(buf)
 }
 
+pub(crate) fn handle_memory_usage(state: &mut GlobalState, _: ()) -> Result<String> {
+    let _p = profile("handle_memory_usage");
+    let mem = state.analysis_host.per_query_memory_usage();
+
+    let mut out = String::new();
+    for (name, bytes) in mem {
+        format_to!(out, "{:>8} {}\n", bytes, name);
+    }
+    Ok(out)
+}
+
 pub(crate) fn handle_syntax_tree(
     snap: GlobalStateSnapshot,
     params: lsp_ext::SyntaxTreeParams,
diff --git a/crates/rust-analyzer/src/lsp_ext.rs b/crates/rust-analyzer/src/lsp_ext.rs
index d225ad5ff..ba8a0231f 100644
--- a/crates/rust-analyzer/src/lsp_ext.rs
+++ b/crates/rust-analyzer/src/lsp_ext.rs
@@ -14,6 +14,14 @@ impl Request for AnalyzerStatus {
     const METHOD: &'static str = "rust-analyzer/analyzerStatus";
 }
 
+pub enum MemoryUsage {}
+
+impl Request for MemoryUsage {
+    type Params = ();
+    type Result = String;
+    const METHOD: &'static str = "rust-analyzer/memoryUsage";
+}
+
 pub enum ReloadWorkspace {}
 
 impl Request for ReloadWorkspace {
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index cfde55431..5900886e7 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -341,6 +341,7 @@ impl GlobalState {
             .on_sync::<lsp_ext::MatchingBrace>(|s, p| {
                 handlers::handle_matching_brace(s.snapshot(), p)
             })?
+            .on_sync::<lsp_ext::MemoryUsage>(|s, p| handlers::handle_memory_usage(s, p))?
             .on::<lsp_ext::AnalyzerStatus>(handlers::handle_analyzer_status)?
             .on::<lsp_ext::SyntaxTree>(handlers::handle_syntax_tree)?
             .on::<lsp_ext::ExpandMacro>(handlers::handle_expand_macro)?