Add -Z hir-stats for collecting statistics on HIR and AST

src/librustc/session/config.rs

@@ -918,6 +918,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
           "the directory the MIR is dumped into"),
     perf_stats: bool = (false, parse_bool, [UNTRACKED],
           "print some performance-related statistics"),
+    hir_stats: bool = (false, parse_bool, [UNTRACKED],
+          "print some statistics about AST and HIR"),
 }
 
 pub fn default_lib_output() -> CrateType {

src/librustc/util/common.rs

@@ -75,6 +75,26 @@ pub fn duration_to_secs_str(dur: Duration) -> String {
     format!("{:.3}", secs)
 }
 
+pub fn to_readable_str(mut val: usize) -> String {
+    let mut groups = vec![];
+    loop {
+        let group = val % 1000;
+
+        val /= 1000;
+
+        if val == 0 {
+            groups.push(format!("{}", group));
+            break
+        } else {
+            groups.push(format!("{:03}", group));
+        }
+    }
+
+    groups.reverse();
+
+    groups.join("_")
+}
+
 pub fn record_time<T, F>(accu: &Cell<Duration>, f: F) -> T where
     F: FnOnce() -> T,
 {
@@ -264,3 +284,17 @@ pub fn path2cstr(p: &Path) -> CString {
 pub fn path2cstr(p: &Path) -> CString {
     CString::new(p.to_str().unwrap()).unwrap()
 }
+
+
+#[test]
+fn test_to_readable_str() {
+    assert_eq!("0", to_readable_str(0));
+    assert_eq!("1", to_readable_str(1));
+    assert_eq!("99", to_readable_str(99));
+    assert_eq!("999", to_readable_str(999));
+    assert_eq!("1_000", to_readable_str(1_000));
+    assert_eq!("1_001", to_readable_str(1_001));
+    assert_eq!("999_999", to_readable_str(999_999));
+    assert_eq!("1_000_000", to_readable_str(1_000_000));
+    assert_eq!("1_234_567", to_readable_str(1_234_567));
+}

src/librustc_driver/driver.rs

@@ -37,7 +37,8 @@ use rustc_typeck as typeck;
 use rustc_privacy;
 use rustc_plugin::registry::Registry;
 use rustc_plugin as plugin;
-use rustc_passes::{ast_validation, no_asm, loops, consts, rvalues, static_recursion};
+use rustc_passes::{ast_validation, no_asm, loops, consts, rvalues,
+                   static_recursion, hir_stats};
 use rustc_const_eval::check_match;
 use super::Compilation;
 
@@ -513,6 +514,10 @@ pub fn phase_1_parse_input<'a>(sess: &'a Session, input: &Input) -> PResult<'a,
         syntax::show_span::run(sess.diagnostic(), s, &krate);
     }
 
+    if sess.opts.debugging_opts.hir_stats {
+        hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
+    }
+
     Ok(krate)
 }
 
@@ -718,6 +723,10 @@ pub fn phase_2_configure_and_expand<'a, F>(sess: &Session,
         println!("Post-expansion node count: {}", count_nodes(&krate));
     }
 
+    if sess.opts.debugging_opts.hir_stats {
+        hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
+    }
+
     if sess.opts.debugging_opts.ast_json {
         println!("{}", json::as_json(&krate));
     }
@@ -758,7 +767,13 @@ pub fn phase_2_configure_and_expand<'a, F>(sess: &Session,
 
     // Lower ast -> hir.
     let hir_forest = time(sess.time_passes(), "lowering ast -> hir", || {
-        hir_map::Forest::new(lower_crate(sess, &krate, &mut resolver), &sess.dep_graph)
+        let hir_crate = lower_crate(sess, &krate, &mut resolver);
+
+        if sess.opts.debugging_opts.hir_stats {
+            hir_stats::print_hir_stats(&hir_crate);
+        }
+
+        hir_map::Forest::new(hir_crate, &sess.dep_graph)
     });
 
     // Discard hygiene data, which isn't required past lowering to HIR.