From: Jan Hubicka <jh@suse.cz>
Date: Mon, 25 May 2020 12:41:33 +0000 (+0200)
Subject: Do not stream redundant stuff
X-Git-Tag: releases/gcc-10.3.0~1041
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0d96c3424bbb5e5f994b78c8f65d8704d215be54;p=thirdparty%2Fgcc.git

Do not stream redundant stuff

as discussed on IRC this adds knob to disable stuff we stream "just for fun"
(or to make it easier to debug streamer desychnonization).

Te size of .o files in gcc subdirectory is reduced form 506MB to 492MB

gcc/

	* lto-streamer-out.c (lto_output_tree): Add streamer_debugging check.
	* lto-streamer.h (streamer_debugging): New constant
	* tree-streamer-in.c (streamer_read_tree_bitfields): Add
	streamer_debugging check.
	(streamer_get_pickled_tree): Likewise.
	* tree-streamer-out.c (pack_ts_base_value_fields): Likewise.

(cherry picked from commit a746f952abb78af9db28a7f3bce442e113877c9c)
(cherry picked from commit 9d679bd7b621c93c000b7d548f34f3438e0d57a8)
---

diff --git a/gcc/lto-streamer-out.c b/gcc/lto-streamer-out.c
index 74ea872e5114..61c21d181fa2 100644
--- a/gcc/lto-streamer-out.c
+++ b/gcc/lto-streamer-out.c
@@ -1710,8 +1710,9 @@ lto_output_tree (struct output_block *ob, tree expr,
 	 will instantiate two different nodes for the same object.  */
       streamer_write_record_start (ob, LTO_tree_pickle_reference);
       streamer_write_uhwi (ob, ix);
-      streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS,
-			   lto_tree_code_to_tag (TREE_CODE (expr)));
+      if (streamer_debugging)
+	streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS,
+			     lto_tree_code_to_tag (TREE_CODE (expr)));
       lto_stats.num_pickle_refs_output++;
     }
   else
diff --git a/gcc/lto-streamer.h b/gcc/lto-streamer.h
index a466fb8b329e..93da3c66fd89 100644
--- a/gcc/lto-streamer.h
+++ b/gcc/lto-streamer.h
@@ -125,6 +125,9 @@ along with GCC; see the file COPYING3.  If not see
 
 typedef unsigned char	lto_decl_flags_t;
 
+/* Stream additional data to LTO object files to make it easier to debug
+   streaming code.  This changes object files.  */
+static const bool streamer_debugging = false;
 
 /* Tags representing the various IL objects written to the bytecode file
    (GIMPLE statements, basic blocks, EH regions, tree nodes, etc).
diff --git a/gcc/tree-streamer-in.c b/gcc/tree-streamer-in.c
index 5b653cdf5ad2..a3aea3d811fc 100644
--- a/gcc/tree-streamer-in.c
+++ b/gcc/tree-streamer-in.c
@@ -487,9 +487,13 @@ streamer_read_tree_bitfields (class lto_input_block *ib,
 
   /* The first word in BP contains the code of the tree that we
      are about to read.  */
-  code = (enum tree_code) bp_unpack_value (&bp, 16);
-  lto_tag_check (lto_tree_code_to_tag (code),
-		 lto_tree_code_to_tag (TREE_CODE (expr)));
+  if (streamer_debugging)
+    {
+      code = (enum tree_code) bp_unpack_value (&bp, 16);
+      lto_tag_check (lto_tree_code_to_tag (code),
+		     lto_tree_code_to_tag (TREE_CODE (expr)));
+    }
+  code = TREE_CODE (expr);
 
   /* Note that all these functions are highly sensitive to changes in
      the types and sizes of each of the fields being packed.  */
@@ -1107,11 +1111,14 @@ streamer_get_pickled_tree (class lto_input_block *ib, class data_in *data_in)
   enum LTO_tags expected_tag;
 
   ix = streamer_read_uhwi (ib);
-  expected_tag = streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
-
   result = streamer_tree_cache_get_tree (data_in->reader_cache, ix);
-  gcc_assert (result
-              && TREE_CODE (result) == lto_tag_to_tree_code (expected_tag));
+
+  if (streamer_debugging)
+    {
+      expected_tag = streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
+      gcc_assert (result
+		  && TREE_CODE (result) == lto_tag_to_tree_code (expected_tag));
+    }
 
   return result;
 }
diff --git a/gcc/tree-streamer-out.c b/gcc/tree-streamer-out.c
index 0b54ffb63f35..7bc97196cf1c 100644
--- a/gcc/tree-streamer-out.c
+++ b/gcc/tree-streamer-out.c
@@ -70,7 +70,8 @@ write_identifier (struct output_block *ob,
 static inline void
 pack_ts_base_value_fields (struct bitpack_d *bp, tree expr)
 {
-  bp_pack_value (bp, TREE_CODE (expr), 16);
+  if (streamer_debugging)
+    bp_pack_value (bp, TREE_CODE (expr), 16);
   if (!TYPE_P (expr))
     {
       bp_pack_value (bp, TREE_SIDE_EFFECTS (expr), 1);