In 2004, we upgraded to binutils 2.14 with did -zcombreloc by default.

In 2013, I implemented the single-entry LRU cache that gets the maximal
symbol reuse from combreloc.  Since then, the ld.so generic relocation
symcache has been a waste of CPU and memory with 0% hit-rate, so kill it.

ok mpi@

4 files changed, 7 insertions, 86 deletions

diff --git a/libexec/ld.so/dlfcn.c b/libexec/ld.so/dlfcn.c
index 016e6316cc8..39fdf27457d 100644
--- a/libexec/ld.so/dlfcn.c
+++ b/libexec/ld.so/dlfcn.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dlfcn.c,v 1.102 2018/10/22 01:59:08 guenther Exp $ */
+/*	$OpenBSD: dlfcn.c,v 1.103 2019/07/21 03:54:16 guenther Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -526,12 +526,6 @@ _dl_show_objects(void)
 		}
 		_dl_tracefmt(outputfd, object, fmt1, fmt2, objtypename);
 	}
-
-	if (_dl_symcachestat_lookups != 0)
-		DL_DEB(("symcache lookups %d hits %d ratio %d% hits\n",
-		    _dl_symcachestat_lookups, _dl_symcachestat_hits,
-		    (_dl_symcachestat_hits * 100) /
-		    _dl_symcachestat_lookups));
 }
 
 lock_cb *
diff --git a/libexec/ld.so/loader.c b/libexec/ld.so/loader.c
index 7e8f60578cb..e7b4e031b54 100644
--- a/libexec/ld.so/loader.c
+++ b/libexec/ld.so/loader.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: loader.c,v 1.182 2019/06/07 16:27:47 deraadt Exp $ */
+/*	$OpenBSD: loader.c,v 1.183 2019/07/21 03:54:16 guenther Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -687,13 +687,9 @@ _dl_boot(const char **argv, char **envp, const long dyn_loff, long *dl_data)
 	return(dl_data[AUX_entry]);
 }
 
-#define DL_SM_SYMBUF_CNT 512
-sym_cache _dl_sm_symcache_buffer[DL_SM_SYMBUF_CNT];
-
 int
 _dl_rtld(elf_object_t *object)
 {
-	size_t sz;
 	struct load_list *llist;
 	int fails = 0;
 
@@ -703,26 +699,6 @@ _dl_rtld(elf_object_t *object)
 	if (object->status & STAT_RELOC_DONE)
 		return 0;
 
-	sz = 0;
-	if (object->nchains < DL_SM_SYMBUF_CNT) {
-		_dl_symcache = _dl_sm_symcache_buffer;
-//		DL_DEB(("using static buffer for %d entries\n",
-//		    object->nchains));
-		_dl_memset(_dl_symcache, 0,
-		    sizeof (sym_cache) * object->nchains);
-	} else {
-		sz = ELF_ROUND(sizeof (sym_cache) * object->nchains,
-		    _dl_pagesz);
-//		DL_DEB(("allocating symcache sz %x with mmap\n", sz));
-
-		_dl_symcache = (void *)_dl_mmap(0, sz, PROT_READ|PROT_WRITE,
-		    MAP_PRIVATE|MAP_ANON, -1, 0);
-		if (_dl_mmap_error(_dl_symcache)) {
-			sz = 0;
-			_dl_symcache = NULL;
-		}
-	}
-
 	/*
 	 * Do relocation information first, then GOT.
 	 */
@@ -741,11 +717,6 @@ _dl_rtld(elf_object_t *object)
 		}
 	}
 
-	if (_dl_symcache != NULL) {
-		if (sz != 0)
-			_dl_munmap( _dl_symcache, sz);
-		_dl_symcache = NULL;
-	}
 	if (fails == 0)
 		object->status |= STAT_RELOC_DONE;
 
diff --git a/libexec/ld.so/resolve.c b/libexec/ld.so/resolve.c
index 2574cc3b953..2b9874ba7b3 100644
--- a/libexec/ld.so/resolve.c
+++ b/libexec/ld.so/resolve.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: resolve.c,v 1.90 2019/07/14 03:23:12 guenther Exp $ */
+/*	$OpenBSD: resolve.c,v 1.91 2019/07/21 03:54:16 guenther Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -518,60 +518,19 @@ _dl_remove_object(elf_object_t *object)
 }
 
 
-sym_cache *_dl_symcache;
-int _dl_symcachestat_hits;
-int _dl_symcachestat_lookups;
-
-
 Elf_Addr
 _dl_find_symbol_bysym(elf_object_t *req_obj, unsigned int symidx,
-    const Elf_Sym **this, int flags, const Elf_Sym *ref_sym, const elf_object_t **pobj)
+    const Elf_Sym **this, int flags, const Elf_Sym *ref_sym,
+    const elf_object_t **pobj)
 {
-	Elf_Addr ret;
 	const Elf_Sym *sym;
 	const char *symn;
-	const elf_object_t *sobj;
-
-	_dl_symcachestat_lookups ++;
-	if (_dl_symcache != NULL &&
-	    symidx < req_obj->nchains &&
-	    _dl_symcache[symidx].obj != NULL &&
-	    _dl_symcache[symidx].sym != NULL &&
-	    _dl_symcache[symidx].flags == flags) {
-
-		_dl_symcachestat_hits++;
-		sobj = _dl_symcache[symidx].obj;
-		*this = _dl_symcache[symidx].sym;
-		if (pobj)
-			*pobj = sobj;
-		return sobj->obj_base;
-	}
 
 	sym = req_obj->dyn.symtab;
 	sym += symidx;
 	symn = req_obj->dyn.strtab + sym->st_name;
 
-	ret = _dl_find_symbol(symn, this, flags, ref_sym, req_obj, &sobj);
-
-	if (pobj)
-		*pobj = sobj;
-
-	if (_dl_symcache != NULL && symidx < req_obj->nchains) {
-#if 0
-		DL_DEB(("cache miss %d %p %p, %p %p %s %s %d %d %s\n",
-		    symidx,
-		    _dl_symcache[symidx].sym, *this,
-		    _dl_symcache[symidx].obj, sobj, sobj->load_name,
-		    sobj->dyn.strtab + (*this)->st_name,
-		    _dl_symcache[symidx].flags, flags, req_obj->load_name));
-#endif
-
-		_dl_symcache[symidx].sym = *this;
-		_dl_symcache[symidx].obj = sobj;
-		_dl_symcache[symidx].flags = flags;
-	}
-
-	return ret;
+	return _dl_find_symbol(symn, this, flags, ref_sym, req_obj, pobj);
 }
 
 static int
diff --git a/libexec/ld.so/resolve.h b/libexec/ld.so/resolve.h
index 82ac21b487b..ac90ac4a0e7 100644
--- a/libexec/ld.so/resolve.h
+++ b/libexec/ld.so/resolve.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: resolve.h,v 1.92 2019/05/11 21:02:35 guenther Exp $ */
+/*	$OpenBSD: resolve.h,v 1.93 2019/07/21 03:54:16 guenther Exp $ */
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -368,9 +368,6 @@ typedef struct sym_cache {
 	int flags;
 } sym_cache;
 
-extern sym_cache *_dl_symcache;
-extern int _dl_symcachestat_hits;
-extern int _dl_symcachestat_lookups;
 TAILQ_HEAD(dlochld, dep_node);
 extern struct dlochld _dlopened_child_list;
 __END_HIDDEN_DECLS