objtool: Optimize find_symbol_*() and read_symbols()
All of: read_symbols(), find_symbol_by_offset(), find_symbol_containing(), find_containing_func() do a linear search of the symbols. Add an RB tree to make it go faster. This about halves objtool runtime on vmlinux.o, from 34s to 18s. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200324160924.499016559@infradead.org
This commit is contained in:
Peter Zijlstra
Родитель
ae358196fa
Коммит
2a362ecc3e
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@ -11,6 +11,7 @@ objtool-y += objtool.o
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objtool-y += libstring.o
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objtool-y += libctype.o
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objtool-y += str_error_r.o
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objtool-y += librbtree.o
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CFLAGS += -I$(srctree)/tools/lib
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@ -25,3 +26,7 @@ $(OUTPUT)libctype.o: ../lib/ctype.c FORCE
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$(OUTPUT)str_error_r.o: ../lib/str_error_r.c FORCE
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$(call rule_mkdir)
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$(call if_changed_dep,cc_o_c)
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$(OUTPUT)librbtree.o: ../lib/rbtree.c FORCE
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$(call rule_mkdir)
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$(call if_changed_dep,cc_o_c)
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@ -27,6 +27,90 @@ static inline u32 str_hash(const char *str)
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return jhash(str, strlen(str), 0);
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}
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static void rb_add(struct rb_root *tree, struct rb_node *node,
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int (*cmp)(struct rb_node *, const struct rb_node *))
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{
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struct rb_node **link = &tree->rb_node;
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struct rb_node *parent = NULL;
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while (*link) {
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parent = *link;
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if (cmp(node, parent) < 0)
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link = &parent->rb_left;
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else
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link = &parent->rb_right;
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}
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rb_link_node(node, parent, link);
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rb_insert_color(node, tree);
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}
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static struct rb_node *rb_find_first(struct rb_root *tree, const void *key,
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int (*cmp)(const void *key, const struct rb_node *))
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{
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struct rb_node *node = tree->rb_node;
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struct rb_node *match = NULL;
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while (node) {
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int c = cmp(key, node);
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if (c <= 0) {
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if (!c)
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match = node;
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node = node->rb_left;
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} else if (c > 0) {
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node = node->rb_right;
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}
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}
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return match;
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}
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static struct rb_node *rb_next_match(struct rb_node *node, const void *key,
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int (*cmp)(const void *key, const struct rb_node *))
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{
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node = rb_next(node);
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if (node && cmp(key, node))
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node = NULL;
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return node;
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}
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#define rb_for_each(tree, node, key, cmp) \
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for ((node) = rb_find_first((tree), (key), (cmp)); \
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(node); (node) = rb_next_match((node), (key), (cmp)))
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static int symbol_to_offset(struct rb_node *a, const struct rb_node *b)
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{
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struct symbol *sa = rb_entry(a, struct symbol, node);
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struct symbol *sb = rb_entry(b, struct symbol, node);
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if (sa->offset < sb->offset)
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return -1;
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if (sa->offset > sb->offset)
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return 1;
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if (sa->len < sb->len)
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return -1;
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if (sa->len > sb->len)
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return 1;
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sa->alias = sb;
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return 0;
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}
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static int symbol_by_offset(const void *key, const struct rb_node *node)
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{
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const struct symbol *s = rb_entry(node, struct symbol, node);
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const unsigned long *o = key;
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if (*o < s->offset)
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return -1;
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if (*o > s->offset + s->len)
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return 1;
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return 0;
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}
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struct section *find_section_by_name(struct elf *elf, const char *name)
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{
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struct section *sec;
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@ -63,22 +147,56 @@ static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)
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struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset)
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{
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struct symbol *sym;
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struct rb_node *node;
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list_for_each_entry(sym, &sec->symbol_list, list)
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if (sym->type != STT_SECTION && sym->offset == offset)
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return sym;
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rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
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struct symbol *s = rb_entry(node, struct symbol, node);
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if (s->offset == offset && s->type != STT_SECTION)
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return s;
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}
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return NULL;
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}
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struct symbol *find_func_by_offset(struct section *sec, unsigned long offset)
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{
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struct symbol *sym;
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struct rb_node *node;
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list_for_each_entry(sym, &sec->symbol_list, list)
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if (sym->type == STT_FUNC && sym->offset == offset)
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return sym;
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rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
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struct symbol *s = rb_entry(node, struct symbol, node);
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if (s->offset == offset && s->type == STT_FUNC)
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return s;
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}
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return NULL;
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}
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struct symbol *find_symbol_containing(struct section *sec, unsigned long offset)
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{
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struct rb_node *node;
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rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
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struct symbol *s = rb_entry(node, struct symbol, node);
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if (s->type != STT_SECTION)
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return s;
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}
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return NULL;
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}
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struct symbol *find_containing_func(struct section *sec, unsigned long offset)
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{
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struct rb_node *node;
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rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
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struct symbol *s = rb_entry(node, struct symbol, node);
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if (s->type == STT_FUNC)
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return s;
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}
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return NULL;
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}
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@ -96,18 +214,6 @@ struct symbol *find_symbol_by_name(struct elf *elf, const char *name)
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return NULL;
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}
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struct symbol *find_symbol_containing(struct section *sec, unsigned long offset)
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{
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struct symbol *sym;
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list_for_each_entry(sym, &sec->symbol_list, list)
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if (sym->type != STT_SECTION &&
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offset >= sym->offset && offset < sym->offset + sym->len)
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return sym;
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return NULL;
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}
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struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
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unsigned int len)
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{
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@ -130,18 +236,6 @@ struct rela *find_rela_by_dest(struct section *sec, unsigned long offset)
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return find_rela_by_dest_range(sec, offset, 1);
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}
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struct symbol *find_containing_func(struct section *sec, unsigned long offset)
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{
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struct symbol *func;
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list_for_each_entry(func, &sec->symbol_list, list)
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if (func->type == STT_FUNC && offset >= func->offset &&
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offset < func->offset + func->len)
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return func;
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return NULL;
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}
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static int read_sections(struct elf *elf)
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{
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Elf_Scn *s = NULL;
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@ -225,8 +319,9 @@ static int read_sections(struct elf *elf)
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static int read_symbols(struct elf *elf)
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{
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struct section *symtab, *sec;
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struct symbol *sym, *pfunc, *alias;
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struct list_head *entry, *tmp;
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struct symbol *sym, *pfunc;
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struct list_head *entry;
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struct rb_node *pnode;
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int symbols_nr, i;
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char *coldstr;
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@ -245,7 +340,7 @@ static int read_symbols(struct elf *elf)
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return -1;
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}
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memset(sym, 0, sizeof(*sym));
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alias = sym;
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sym->alias = sym;
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sym->idx = i;
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@ -283,29 +378,12 @@ static int read_symbols(struct elf *elf)
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sym->offset = sym->sym.st_value;
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sym->len = sym->sym.st_size;
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/* sorted insert into a per-section list */
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rb_add(&sym->sec->symbol_tree, &sym->node, symbol_to_offset);
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pnode = rb_prev(&sym->node);
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if (pnode)
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entry = &rb_entry(pnode, struct symbol, node)->list;
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else
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entry = &sym->sec->symbol_list;
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list_for_each_prev(tmp, &sym->sec->symbol_list) {
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struct symbol *s;
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s = list_entry(tmp, struct symbol, list);
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if (sym->offset > s->offset) {
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entry = tmp;
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break;
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}
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if (sym->offset == s->offset) {
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if (sym->len && sym->len == s->len && alias == sym)
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alias = s;
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if (sym->len >= s->len) {
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entry = tmp;
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break;
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}
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}
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}
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sym->alias = alias;
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list_add(&sym->list, entry);
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hash_add(elf->symbol_hash, &sym->hash, sym->idx);
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}
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@ -10,6 +10,7 @@
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#include <gelf.h>
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#include <linux/list.h>
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#include <linux/hashtable.h>
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#include <linux/rbtree.h>
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#include <linux/jhash.h>
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#ifdef LIBELF_USE_DEPRECATED
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@ -29,6 +30,7 @@ struct section {
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struct hlist_node hash;
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struct hlist_node name_hash;
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GElf_Shdr sh;
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struct rb_root symbol_tree;
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struct list_head symbol_list;
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struct list_head rela_list;
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DECLARE_HASHTABLE(rela_hash, 16);
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@ -43,6 +45,7 @@ struct section {
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struct symbol {
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struct list_head list;
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struct rb_node node;
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struct hlist_node hash;
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GElf_Sym sym;
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struct section *sec;
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