Indicate both start and end of pass RSS in time-passes output

Previously, only the end of pass RSS was indicated. This could easily
lead one to believe that the change in RSS from one pass to the next was
attributable to the second pass, when in fact it occurred between the
end of the first pass and the start of the second.

Also, improve alignment of columns.

1 files changed, 9 insertions, 4 deletions

diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index 15b984acac5..8295e88f75a 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -16,7 +16,7 @@ pub extern crate rustc_plugin_impl as plugin;
 
 use rustc_ast as ast;
 use rustc_codegen_ssa::{traits::CodegenBackend, CodegenResults};
-use rustc_data_structures::profiling::print_time_passes_entry;
+use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry};
 use rustc_data_structures::sync::SeqCst;
 use rustc_errors::registry::{InvalidErrorCode, Registry};
 use rustc_errors::{ErrorReported, PResult};
@@ -1312,7 +1312,8 @@ pub fn init_env_logger(env: &str) {
 }
 
 pub fn main() -> ! {
-    let start = Instant::now();
+    let start_time = Instant::now();
+    let start_rss = get_resident_set_size();
     init_rustc_env_logger();
     let mut callbacks = TimePassesCallbacks::default();
     install_ice_hook();
@@ -1330,7 +1331,11 @@ pub fn main() -> ! {
             .collect::<Vec<_>>();
         RunCompiler::new(&args, &mut callbacks).run()
     });
-    // The extra `\t` is necessary to align this label with the others.
-    print_time_passes_entry(callbacks.time_passes, "\ttotal", start.elapsed());
+
+    if callbacks.time_passes {
+        let end_rss = get_resident_set_size();
+        print_time_passes_entry("total", start_time.elapsed(), start_rss, end_rss);
+    }
+
     process::exit(exit_code)
 }