From 88e0476bd024ef83052479588278669f56a346e2 Mon Sep 17 00:00:00 2001
From: Graydon Hoare <graydon@mozilla.com>
Date: Mon, 27 Aug 2012 16:53:54 -0700
Subject: [PATCH] Add some counters to metadata.

---
 src/rustc/driver/session.rs   |  5 ++-
 src/rustc/metadata/encoder.rs | 59 ++++++++++++++++++++++++++++++++++-
 2 files changed, 62 insertions(+), 2 deletions(-)

diff --git a/src/rustc/driver/session.rs b/src/rustc/driver/session.rs
index 0a99c53f83ae..56d2cc86aa76 100644
--- a/src/rustc/driver/session.rs
+++ b/src/rustc/driver/session.rs
@@ -42,6 +42,7 @@ const borrowck_note_loan: uint = 4096;
 const no_landing_pads: uint = 8192;
 const debug_llvm: uint = 16384;
 const count_type_sizes: uint = 32768;
+const meta_stats: uint = 65536;
 
 fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
     ~[(~"ppregions", ~"prettyprint regions with \
@@ -66,7 +67,8 @@ fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
       no_landing_pads),
      (~"debug-llvm", ~"enable debug output from LLVM", debug_llvm),
      (~"count-type-sizes", ~"count the sizes of aggregate types",
-      count_type_sizes)
+      count_type_sizes),
+     (~"meta-stats", ~"gather metadata statistics", meta_stats)
     ]
 }
 
@@ -198,6 +200,7 @@ impl session {
     fn count_type_sizes() -> bool { self.debugging_opt(count_type_sizes) }
     fn time_llvm_passes() -> bool { self.debugging_opt(time_llvm_passes) }
     fn trans_stats() -> bool { self.debugging_opt(trans_stats) }
+    fn meta_stats() -> bool { self.debugging_opt(meta_stats) }
     fn no_asm_comments() -> bool { self.debugging_opt(no_asm_comments) }
     fn no_verify() -> bool { self.debugging_opt(no_verify) }
     fn trace() -> bool { self.debugging_opt(trace) }
diff --git a/src/rustc/metadata/encoder.rs b/src/rustc/metadata/encoder.rs
index beaabbe8b956..5764e5ace59e 100644
--- a/src/rustc/metadata/encoder.rs
+++ b/src/rustc/metadata/encoder.rs
@@ -54,9 +54,23 @@ type encode_parms = {
     encode_inlined_item: encode_inlined_item
 };
 
+type stats = {
+    mut inline_bytes: uint,
+    mut attr_bytes: uint,
+    mut dep_bytes: uint,
+    mut item_bytes: uint,
+    mut index_bytes: uint,
+    mut zero_bytes: uint,
+    mut total_bytes: uint,
+
+    mut n_inlines: uint
+};
+
 enum encode_ctxt = {
     diag: span_handler,
     tcx: ty::ctxt,
+    buf: io::MemBuffer,
+    stats: stats,
     reachable: hashmap<ast::node_id, ()>,
     reexports: ~[(~str, def_id)],
     reexports2: middle::resolve3::ExportMap2,
@@ -1072,9 +1086,21 @@ fn encode_hash(ebml_w: ebml::writer, hash: ~str) {
 }
 
 fn encode_metadata(parms: encode_parms, crate: @crate) -> ~[u8] {
+    let buf = io::mem_buffer();
+    let stats =
+        {mut inline_bytes: 0,
+         mut attr_bytes: 0,
+         mut dep_bytes: 0,
+         mut item_bytes: 0,
+         mut index_bytes: 0,
+         mut zero_bytes: 0,
+         mut total_bytes: 0,
+         mut n_inlines: 0};
     let ecx: @encode_ctxt = @encode_ctxt({
         diag: parms.diag,
         tcx: parms.tcx,
+        buf: buf,
+        stats: stats,
         reachable: parms.reachable,
         reexports: parms.reexports,
         reexports2: parms.reexports2,
@@ -1086,24 +1112,55 @@ fn encode_metadata(parms: encode_parms, crate: @crate) -> ~[u8] {
         type_abbrevs: ty::new_ty_hash()
      });
 
-    let buf = io::mem_buffer();
     let buf_w = io::mem_buffer_writer(buf);
     let ebml_w = ebml::writer(buf_w);
 
     encode_hash(ebml_w, ecx.link_meta.extras_hash);
 
+    let mut i = buf.pos;
     let crate_attrs = synthesize_crate_attrs(ecx, crate);
     encode_attributes(ebml_w, crate_attrs);
+    ecx.stats.attr_bytes = buf.pos - i;
 
+    i = buf.pos;
     encode_crate_deps(ecx, ebml_w, ecx.cstore);
+    ecx.stats.dep_bytes = buf.pos - i;
 
     // Encode and index the items.
     ebml_w.start_tag(tag_items);
+    i = buf.pos;
     let items_index = encode_info_for_items(ecx, ebml_w, crate);
+    ecx.stats.item_bytes = buf.pos - i;
+
+    i = buf.pos;
     let items_buckets = create_index(items_index, hash_node_id);
     encode_index(ebml_w, items_buckets, write_int);
+    ecx.stats.index_bytes = buf.pos - i;
     ebml_w.end_tag();
 
+    ecx.stats.total_bytes = buf.pos;
+
+    if (parms.tcx.sess.meta_stats()) {
+
+        do buf.buf.borrow |v| {
+            do v.each |e| {
+                if e == 0 {
+                    ecx.stats.zero_bytes += 1;
+                }
+                true
+            }
+        }
+
+        io::println("metadata stats:");
+        io::println(fmt!("    inline bytes: %u", ecx.stats.inline_bytes));
+        io::println(fmt!(" attribute bytes: %u", ecx.stats.attr_bytes));
+        io::println(fmt!("       dep bytes: %u", ecx.stats.dep_bytes));
+        io::println(fmt!("      item bytes: %u", ecx.stats.item_bytes));
+        io::println(fmt!("     index bytes: %u", ecx.stats.index_bytes));
+        io::println(fmt!("      zero bytes: %u", ecx.stats.zero_bytes));
+        io::println(fmt!("     total bytes: %u", ecx.stats.total_bytes));
+    }
+
     // Pad this, since something (LLVM, presumably) is cutting off the
     // remaining % 4 bytes.
     buf_w.write(&[0u8, 0u8, 0u8, 0u8]);