Add a command to compute memory usage statistics

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,

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 {

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)?