[binutils-gdb] gas: xtensa: speed up find_trampoline_seg

[Max Filippov <jcmvbkbc at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=407e1140841f7fc337e90a7ba4482fb5a10c1701

commit 407e1140841f7fc337e90a7ba4482fb5a10c1701
Author: Max Filippov <jcmvbkbc@gmail.com>
Date:   Mon Nov 20 06:35:06 2017 -0800

    gas: xtensa: speed up find_trampoline_seg
    
    find_trampoline_seg takes noticeable time when assembling source with
    many sections. Cache the result of the most recent search and check it
    first. No functional changes.
    
    gas/
    2017-11-27  Max Filippov  <jcmvbkbc@gmail.com>
    
    	* config/tc-xtensa.c (find_trampoline_seg): Add static variable
    	that caches the result of the most recent search.

Diff:
---
 gas/ChangeLog          | 5 +++++
 gas/config/tc-xtensa.c | 9 ++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 92d0c36..81f9f83 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,10 @@
 2017-11-27  Max Filippov  <jcmvbkbc@gmail.com>
 
+	* config/tc-xtensa.c (find_trampoline_seg): Add static variable
+	that caches the result of the most recent search.
+
+2017-11-27  Max Filippov  <jcmvbkbc@gmail.com>
+
 	* config/tc-xtensa.c (trampoline_chain_entry, trampoline_chain)
 	(trampoline_chain_index): New structures.
 	(trampoline_index): Add chain_index field.
diff --git a/gas/config/tc-xtensa.c b/gas/config/tc-xtensa.c
index 9defd73..ce7eb49 100644
--- a/gas/config/tc-xtensa.c
+++ b/gas/config/tc-xtensa.c
@@ -7453,11 +7453,18 @@ static struct trampoline_seg *
 find_trampoline_seg (asection *seg)
 {
   struct trampoline_seg *ts = trampoline_seg_list.next;
+  static struct trampoline_seg *mr;
+
+  if (mr && mr->seg == seg)
+    return mr;
 
   for ( ; ts; ts = ts->next)
     {
       if (ts->seg == seg)
-	return ts;
+	{
+	  mr = ts;
+	  return ts;
+	}
     }
 
   return NULL;