From 35835446e4115755fc48a367d58ea57f1b88dd1e Mon Sep 17 00:00:00 2001 From: Joern Rennecke Date: Wed, 19 May 2004 14:15:55 +0000 Subject: [PATCH] * NEWS: Mention new linker map file generation and the --reduce-memory-overheads option. * ld.texinfo: Document --reduce-memory-overheads option. * ld.h (map_symbol_def): New struct. (struct user_section_struct, section_userdata_type): Rename to: (struct lean_user_section_struct, lean_section_userdata_type). (struct fat_user_section_struct, fat_section_userdata_type): New. (SECTION_USERDATA_SIZE): Define. (args_type): New member reduce_memory_overheads. * ldlang.c (map_obstack): New static variable. (init_map_userdata, print_all_symbols, sort_def_symbol): New functions. (lang_map): Unless command_line.reduce_memory_overheads is set, initialize lists of defined symbols for each section. (print_input_section): Unless command_line.reduce_memory_overheads is set, use print_all_symbols. (init_os): Use lean_section_userdata_type / SECTION_USERDATA_SIZE. * ldmain.c (main): Initialize command_line.reduce_memory_overheads. * lexsup.c (enum option_values): Add OPTION_REDUCE_MEMORY_OVERHEADS. (ld_options): Add entry for --reduce-memory-overheads. (parse_args): Handle OPTION_REDUCE_MEMORY_OVERHEADS. --- ld/ChangeLog | 23 +++++++++++++++++ ld/NEWS | 6 +++++ ld/ld.h | 31 ++++++++++++++++++++--- ld/ld.texinfo | 8 ++++++ ld/ldlang.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--- ld/ldmain.c | 1 + ld/lexsup.c | 10 ++++++-- 7 files changed, 149 insertions(+), 9 deletions(-) diff --git a/ld/ChangeLog b/ld/ChangeLog index a96006a..38bbbe7 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,26 @@ +2004-05-19 J"orn Rennecke + + * NEWS: Mention new linker map file generation and the + --reduce-memory-overheads option. + * ld.texinfo: Document --reduce-memory-overheads option. + * ld.h (map_symbol_def): New struct. + (struct user_section_struct, section_userdata_type): Rename to: + (struct lean_user_section_struct, lean_section_userdata_type). + (struct fat_user_section_struct, fat_section_userdata_type): New. + (SECTION_USERDATA_SIZE): Define. + (args_type): New member reduce_memory_overheads. + * ldlang.c (map_obstack): New static variable. + (init_map_userdata, print_all_symbols, sort_def_symbol): New functions. + (lang_map): Unless command_line.reduce_memory_overheads is set, + initialize lists of defined symbols for each section. + (print_input_section): Unless command_line.reduce_memory_overheads + is set, use print_all_symbols. + (init_os): Use lean_section_userdata_type / SECTION_USERDATA_SIZE. + * ldmain.c (main): Initialize command_line.reduce_memory_overheads. + * lexsup.c (enum option_values): Add OPTION_REDUCE_MEMORY_OVERHEADS. + (ld_options): Add entry for --reduce-memory-overheads. + (parse_args): Handle OPTION_REDUCE_MEMORY_OVERHEADS. + 2004-05-19 Jakub Jelinek * ldgram.y (sect_constraint): New. diff --git a/ld/NEWS b/ld/NEWS index cec229b..a33c6dc 100644 --- a/ld/NEWS +++ b/ld/NEWS @@ -1,5 +1,11 @@ -*- text -*- +* Linker map files are now generated with an O(N) algorithm for finding symbols + that are defined in each section. This uses about 40% more memory for + symbols than the old O(N^2) algorithm. You can use the new + --reduce-memory-overheads option to select the old algorithm; this option + might also be used in the future to select similar tradeoffs. + * New PE --large-address-aware option to indicate executables support virtual addresses greater than 2 gigabytes. diff --git a/ld/ld.h b/ld/ld.h index dde4cfe..1061c35 100644 --- a/ld/ld.h +++ b/ld/ld.h @@ -78,11 +78,32 @@ struct wildcard_list { struct wildcard_spec spec; }; +struct map_symbol_def { + struct bfd_link_hash_entry *entry; + struct map_symbol_def *next; +}; + /* Extra information we hold on sections */ -typedef struct user_section_struct { - /* Pointer to the section where this data will go */ +typedef struct lean_user_section_struct { + /* For output sections: pointer to the section where this data will go. */ + struct lang_input_statement_struct *file; +} lean_section_userdata_type; + +/* The initial part of fat_user_section_struct has to be idential with + lean_user_section_struct. */ +typedef struct fat_user_section_struct { + /* For output sections: pointer to the section where this data will go. */ struct lang_input_statement_struct *file; -} section_userdata_type; + /* For input sections, when writing a map file: head / tail of a linked + list of hash table entries for symbols defined in this section. */ + struct map_symbol_def *map_symbol_def_head; + struct map_symbol_def **map_symbol_def_tail; +} fat_section_userdata_type; + +#define SECTION_USERDATA_SIZE \ + (command_line.reduce_memory_overheads \ + ? sizeof (lean_section_userdata_type) \ + : sizeof (fat_section_userdata_type)) #define get_userdata(x) ((x)->userdata) @@ -154,6 +175,10 @@ typedef struct { input files. */ bfd_boolean accept_unknown_input_arch; + /* If TRUE reduce memory overheads, at the expense of speed. + This will cause map file generation to use an O(N^2) algorithm. */ + bfd_boolean reduce_memory_overheads; + } args_type; extern args_type command_line; diff --git a/ld/ld.texinfo b/ld/ld.texinfo index ceaecd1..b78d1b0 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -1734,6 +1734,14 @@ If you specify @option{--disable-new-dtags}, no new dynamic tags will be created. By default, the new dynamic tags are not created. Note that those options are only available for ELF systems. +@kindex --reduce-memory-overheads +@item --reduce-memory-overheads +This option reduces memory requirements at ld runtime, at the expense of +linking speed. This was introduced to to select the old O(n^2) algorithm +for link map file generation, rather than the new O(n) algorithm which uses +about 40% more memory for symbol storage. It may be also be used for +similar such tradeoffs in the future. + @end table @c man end diff --git a/ld/ldlang.c b/ld/ldlang.c index 8bbf041..a19b46a 100644 --- a/ld/ldlang.c +++ b/ld/ldlang.c @@ -47,6 +47,7 @@ /* Locals variables. */ static struct obstack stat_obstack; +static struct obstack map_obstack; #define obstack_chunk_alloc xmalloc #define obstack_chunk_free free @@ -65,6 +66,7 @@ static struct bfd_hash_table lang_definedness_table; /* Forward declarations. */ static void exp_init_os (etree_type *); +static void init_map_userdata (bfd *, asection *, void *); static bfd_boolean wildcardp (const char *); static lang_input_statement_type *lookup_name (const char *); static bfd_boolean load_symbols (lang_input_statement_type *, @@ -72,6 +74,8 @@ static bfd_boolean load_symbols (lang_input_statement_type *, static struct bfd_hash_entry *lang_definedness_newfunc (struct bfd_hash_entry *, struct bfd_hash_table *, const char *); static void insert_undefined (const char *); +static void print_all_symbols (asection *); +static bfd_boolean sort_def_symbol (struct bfd_link_hash_entry *, void *); static void print_statement (lang_statement_union_type *, lang_output_section_statement_type *); static void print_statement_list (lang_statement_union_type *, @@ -688,6 +692,7 @@ void lang_map (void) { lang_memory_region_type *m; + bfd *p; minfo (_("\nMemory Configuration\n\n")); fprintf (config.map_file, "%-16s %-18s %-18s %s\n", @@ -733,15 +738,66 @@ lang_map (void) fprintf (config.map_file, _("\nLinker script and memory map\n\n")); + if (! command_line.reduce_memory_overheads) + { + obstack_begin (&map_obstack, 1000); + for (p = link_info.input_bfds; p != (bfd *) NULL; p = p->link_next) + bfd_map_over_sections (p, init_map_userdata, 0); + bfd_link_hash_traverse (link_info.hash, sort_def_symbol, 0); + } print_statements (); } +static void +init_map_userdata (abfd, sec, data) + bfd *abfd ATTRIBUTE_UNUSED; + asection *sec; + void *data ATTRIBUTE_UNUSED; +{ + fat_section_userdata_type *new_data + = ((fat_section_userdata_type *) (stat_alloc + (sizeof (fat_section_userdata_type)))); + + ASSERT (get_userdata (sec) == NULL); + get_userdata (sec) = new_data; + new_data->map_symbol_def_tail = &new_data->map_symbol_def_head; +} + +static bfd_boolean +sort_def_symbol (hash_entry, info) + struct bfd_link_hash_entry *hash_entry; + void *info ATTRIBUTE_UNUSED; +{ + if (hash_entry->type == bfd_link_hash_defined + || hash_entry->type == bfd_link_hash_defweak) + { + struct fat_user_section_struct *ud; + struct map_symbol_def *def; + + ud = get_userdata (hash_entry->u.def.section); + if (! ud) + { + /* ??? What do we have to do to initialize this beforehand? */ + /* The first time we get here is bfd_abs_section... */ + init_map_userdata (0, hash_entry->u.def.section, 0); + ud = get_userdata (hash_entry->u.def.section); + } + else if (!ud->map_symbol_def_tail) + ud->map_symbol_def_tail = &ud->map_symbol_def_head; + def = (struct map_symbol_def *) obstack_alloc (&map_obstack, sizeof *def); + def->entry = hash_entry; + *ud->map_symbol_def_tail = def; + ud->map_symbol_def_tail = &def->next; + } + return TRUE; +} + /* Initialize an output section. */ static void init_os (lang_output_section_statement_type *s) { - section_userdata_type *new; + lean_section_userdata_type *new; if (s->bfd_section != NULL) return; @@ -749,7 +805,7 @@ init_os (lang_output_section_statement_type *s) if (strcmp (s->name, DISCARD_SECTION_NAME) == 0) einfo (_("%P%F: Illegal use of `%s' section\n"), DISCARD_SECTION_NAME); - new = stat_alloc (sizeof (section_userdata_type)); + new = stat_alloc (SECTION_USERDATA_SIZE); s->bfd_section = bfd_get_section_by_name (output_bfd, s->name); if (s->bfd_section == NULL) @@ -2367,7 +2423,7 @@ print_input_statement (lang_input_statement_type *statm) } /* Print all symbols defined in a particular section. This is called - via bfd_link_hash_traverse. */ + via bfd_link_hash_traverse, or by print_all_symbols. */ static bfd_boolean print_one_symbol (struct bfd_link_hash_entry *hash_entry, void *ptr) @@ -2393,6 +2449,18 @@ print_one_symbol (struct bfd_link_hash_entry *hash_entry, void *ptr) return TRUE; } +static void +print_all_symbols (sec) + asection *sec; +{ + struct fat_user_section_struct *ud = get_userdata (sec); + struct map_symbol_def *def; + + *ud->map_symbol_def_tail = 0; + for (def = ud->map_symbol_def_head; def; def = def->next) + print_one_symbol (def->entry, sec); +} + /* Print information about an input section to the map file. */ static void @@ -2445,7 +2513,10 @@ print_input_section (lang_input_section_type *in) minfo (_("%W (size before relaxing)\n"), i->_raw_size); } - bfd_link_hash_traverse (link_info.hash, print_one_symbol, i); + if (command_line.reduce_memory_overheads) + bfd_link_hash_traverse (link_info.hash, print_one_symbol, i); + else + print_all_symbols (i); print_dot = (i->output_section->vma + i->output_offset + TO_ADDR (size)); diff --git a/ld/ldmain.c b/ld/ldmain.c index eb036b0..f3df44f 100644 --- a/ld/ldmain.c +++ b/ld/ldmain.c @@ -274,6 +274,7 @@ main (int argc, char **argv) command_line.warn_mismatch = TRUE; command_line.check_section_addresses = TRUE; command_line.accept_unknown_input_arch = FALSE; + command_line.reduce_memory_overheads = FALSE; /* We initialize DEMANGLING based on the environment variable COLLECT_NO_DEMANGLE. The gcc collect2 program will demangle the diff --git a/ld/lexsup.c b/ld/lexsup.c index b377bd4..fcca4d3 100644 --- a/ld/lexsup.c +++ b/ld/lexsup.c @@ -142,7 +142,8 @@ enum option_values OPTION_PIE, OPTION_UNRESOLVED_SYMBOLS, OPTION_WARN_UNRESOLVED_SYMBOLS, - OPTION_ERROR_UNRESOLVED_SYMBOLS + OPTION_ERROR_UNRESOLVED_SYMBOLS, + OPTION_REDUCE_MEMORY_OVERHEADS }; /* The long options. This structure is used for both the option @@ -445,7 +446,9 @@ static const struct ld_option ld_options[] = { {"no-as-needed", no_argument, NULL, OPTION_NO_AS_NEEDED}, '\0', NULL, N_("Always set DT_NEEDED for following dynamic libs"), TWO_DASHES }, { {"wrap", required_argument, NULL, OPTION_WRAP}, - '\0', N_("SYMBOL"), N_("Use wrapper functions for SYMBOL"), TWO_DASHES } + '\0', N_("SYMBOL"), N_("Use wrapper functions for SYMBOL"), TWO_DASHES }, + { {"reduce-memory-overheads", no_argument, NULL, OPTION_REDUCE_MEMORY_OVERHEADS}, + '\0', NULL, N_("reduce memory overheads, possibly taking much longer"), TWO_DASHES }, }; #define OPTION_COUNT ARRAY_SIZE (ld_options) @@ -1221,6 +1224,9 @@ parse_args (unsigned argc, char **argv) case OPTION_FINI: link_info.fini_function = optarg; break; + case OPTION_REDUCE_MEMORY_OVERHEADS: + command_line.reduce_memory_overheads = TRUE; + break; } } -- 2.7.4