svn commit: r348431 - head/contrib/elftoolchain/elfcopy

[Mark Johnston]

Author: markj
Date: Thu May 30 15:28:48 2019
New Revision: 348431
URL: https://svnweb.freebsd.org/changeset/base/348431

Log:
  elfcopy: Optimize for insertions at the end of the section list.
  
  This is the common case when strip(1) is creating the output file.
  The change provides a significant speedup when running on ELF files with
  many sections.
  
  PR:		234949
  Reviewed by:	emaste
  MFC after:	1 week
  Sponsored by:	The FreeBSD Foundation
  Differential Revision:	https://reviews.freebsd.org/D20444

Modified:
  head/contrib/elftoolchain/elfcopy/elfcopy.h
  head/contrib/elftoolchain/elfcopy/sections.c

Modified: head/contrib/elftoolchain/elfcopy/elfcopy.h
==============================================================================
--- head/contrib/elftoolchain/elfcopy/elfcopy.h	Thu May 30 15:26:39 2019	(r348430)
+++ head/contrib/elftoolchain/elfcopy/elfcopy.h	Thu May 30 15:28:48 2019	(r348431)
@@ -138,6 +138,8 @@ struct section {
 	TAILQ_ENTRY(section) sec_list;	/* next section */
 };
 
+TAILQ_HEAD(sectionlist, section);
+
 /* Internal data structure for segments. */
 struct segment {
 	uint64_t	vaddr;	/* virtual addr (VMA) */

Modified: head/contrib/elftoolchain/elfcopy/sections.c
==============================================================================
--- head/contrib/elftoolchain/elfcopy/sections.c	Thu May 30 15:26:39 2019	(r348430)
+++ head/contrib/elftoolchain/elfcopy/sections.c	Thu May 30 15:28:48 2019	(r348431)
@@ -314,18 +314,18 @@ insert_to_sec_list(struct elfcopy *ecp, struct section
 {
 	struct section *s;
 
-	if (!tail) {
+	if (tail || TAILQ_EMPTY(&ecp->v_sec) ||
+	    TAILQ_LAST(&ecp->v_sec, sectionlist)->off <= sec->off) {
+		TAILQ_INSERT_TAIL(&ecp->v_sec, sec, sec_list);
+	} else {
 		TAILQ_FOREACH(s, &ecp->v_sec, sec_list) {
 			if (sec->off < s->off) {
 				TAILQ_INSERT_BEFORE(s, sec, sec_list);
-				goto inc_nos;
+				break;
 			}
 		}
 	}
 
-	TAILQ_INSERT_TAIL(&ecp->v_sec, sec, sec_list);
-
-inc_nos:
 	if (sec->pseudo == 0)
 		ecp->nos++;
 }