From 02f9c6cfe286ebd1f39106ae77245c5514ec6919 Mon Sep 17 00:00:00 2001 From: Paul Pluzhnikov Date: Mon, 31 Oct 2011 16:27:54 -0700 Subject: [PATCH] Use extend_alloca in _dl_map_object_deps. --- ChangeLog | 5 +++++ elf/dl-deps.c | 19 +++++++++++++++++-- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index 83a64e8..6e247ec 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2011-10-31 Paul Pluzhnikov + + * elf/dl-deps.c (_dl_map_object_deps): Reuse alloca space to reduce + stack usage. + 2011-10-31 Ulrich Drepper [BZ #13367] diff --git a/elf/dl-deps.c b/elf/dl-deps.c index 95b1088..a1ba3d1 100644 --- a/elf/dl-deps.c +++ b/elf/dl-deps.c @@ -188,6 +188,10 @@ _dl_map_object_deps (struct link_map *map, /* Pointer to last unique object. */ tail = &known[nlist - 1]; + /* No alloca'd space yet. */ + struct link_map **needed_space = NULL; + size_t needed_space_bytes = 0; + /* Process each element of the search list, loading each of its auxiliary objects and immediate dependencies. Auxiliary objects will be added in the list before the object itself and @@ -216,8 +220,19 @@ _dl_map_object_deps (struct link_map *map, dependencies of this object. */ if (l->l_searchlist.r_list == NULL && l->l_initfini == NULL && l != map && l->l_ldnum > 0) - needed = (struct link_map **) alloca (l->l_ldnum - * sizeof (struct link_map *)); + { + /* 16-align so extend_alloca has a chance to re-use the space. + Note that extend_alloca is broken for recent versions of GCC + on x86: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50938 */ + size_t new_size + = (l->l_ldnum * sizeof (struct link_map *) + 15) & ~15; + + if (new_size > needed_space_bytes) + needed_space + = extend_alloca (needed_space, needed_space_bytes, new_size); + + needed = needed_space; + } if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG]) { -- 2.7.4