From 2d643429defea3c00819c1d9a288d424ad76a825 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Fri, 21 May 2004 15:38:04 +0000 Subject: Add --hash-size switch to the linker --- ld/ChangeLog | 15 +++++++++++++++ ld/NEWS | 8 ++++++++ ld/ld.h | 5 ++++- ld/ld.texinfo | 18 ++++++++++++++++-- ld/ldmain.c | 4 ++++ ld/lexsup.c | 22 ++++++++++++++++++++-- 6 files changed, 67 insertions(+), 5 deletions(-) (limited to 'ld') diff --git a/ld/ChangeLog b/ld/ChangeLog index 38bbbe7..46e4865 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,18 @@ +2004-05-21 Andy Chittenden + + * ld.h (ld_config_type): Add new field: hash_table_size. + * ldmain.c: Initialise the new field to zero. If it is non-zero + after parsing the linker's command line call + bfd_hash_set_default_size. + * lexsup.c (option_values): Add OPTION_HASH_SIZE. + (ld_options): Add hash-size. + (parse_args): Parse --hash-size option. Allow + --reduce-memory-overheads to set the default hash table size as + well. + * ld.texinfo: Document the new switch. Also mention that + --reduce-memory-overheads can affect the hash table size. + * NEWS: Mention the new feature. + 2004-05-19 J"orn Rennecke * NEWS: Mention new linker map file generation and the diff --git a/ld/NEWS b/ld/NEWS index a33c6dc..1d07084 100644 --- a/ld/NEWS +++ b/ld/NEWS @@ -1,11 +1,19 @@ -*- text -*- +* A new linker command line switch has been added which allows the hash table + size to be set to a suitable prime value near to its argument. This switch + is --hash-size=. Also if the switch --reduce-memory-overheads is + used, and --hash-size has not been used, then the default value will be set + to 1021. + * 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. +Changes in 2.15: + * 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 1061c35..2bcf7d2 100644 --- a/ld/ld.h +++ b/ld/ld.h @@ -1,5 +1,5 @@ /* ld.h -- general linker header file - Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002 + Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2004 Free Software Foundation, Inc. This file is part of GLD, the Gnu Linker. @@ -241,6 +241,9 @@ typedef struct { /* If set, only search library directories explicitly selected on the command line. */ bfd_boolean only_cmd_line_lib_dirs; + + /* The size of the hash table to use. */ + bfd_size_type hash_table_size; } ld_config_type; extern ld_config_type config; diff --git a/ld/ld.texinfo b/ld/ld.texinfo index b78d1b0..db87e3f 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -1734,13 +1734,27 @@ 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 --hash-size=@var{number} +Set the default size of the linker's hash tables to a prime number +close to @var{number}. Increasing this value can reduce the length of +time it takes the linker to perform its tasks, at the expense of +increasing the linker's memory requirements. Similarly reducing this +value can reduce the memory requirements at the expense of speed. + @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. +about 40% more memory for symbol storage. + +Another affect of the switch is to set the default hash table size to +1021, which again saves memory at the cost of lengthening the linker's +run time. This is not done however if the *option{--hash-size} switch +has been used. + +The @option{--reduce-memory-overheads} switch may be also be used to +enable other tradeoffs in future versions of the linker. @end table diff --git a/ld/ldmain.c b/ld/ldmain.c index f3df44f..f1804c4 100644 --- a/ld/ldmain.c +++ b/ld/ldmain.c @@ -267,6 +267,7 @@ main (int argc, char **argv) config.has_shared = FALSE; config.split_by_reloc = (unsigned) -1; config.split_by_file = (bfd_size_type) -1; + config.hash_table_size = 0; command_line.force_common_definition = FALSE; command_line.inhibit_common_definition = FALSE; command_line.interpreter = NULL; @@ -344,6 +345,9 @@ main (int argc, char **argv) lang_has_input_file = FALSE; parse_args (argc, argv); + if (config.hash_table_size != 0) + bfd_hash_set_default_size (config.hash_table_size); + ldemul_set_symbols (); if (link_info.relocatable) diff --git a/ld/lexsup.c b/ld/lexsup.c index fcca4d3..5137341 100644 --- a/ld/lexsup.c +++ b/ld/lexsup.c @@ -118,6 +118,7 @@ enum option_values OPTION_FORCE_EXE_SUFFIX, OPTION_GC_SECTIONS, OPTION_NO_GC_SECTIONS, + OPTION_HASH_SIZE, OPTION_CHECK_SECTIONS, OPTION_NO_CHECK_SECTIONS, OPTION_NO_UNDEFINED, @@ -328,6 +329,8 @@ static const struct ld_option ld_options[] = { {"no-gc-sections", no_argument, NULL, OPTION_NO_GC_SECTIONS}, '\0', NULL, N_("Don't remove unused sections (default)"), TWO_DASHES }, + { {"hash-size=", required_argument, NULL, OPTION_HASH_SIZE}, + '\0', NULL, N_("Set default hash table size close to "), TWO_DASHES }, { {"help", no_argument, NULL, OPTION_HELP}, '\0', NULL, N_("Print option help"), TWO_DASHES }, { {"init", required_argument, NULL, OPTION_INIT}, @@ -364,6 +367,8 @@ static const struct ld_option ld_options[] = '\0', N_("TARGET"), N_("Specify target of output file"), EXACTLY_TWO_DASHES }, { {"qmagic", no_argument, NULL, OPTION_IGNORE}, '\0', NULL, N_("Ignored for Linux compatibility"), ONE_DASH }, + { {"reduce-memory-overheads", no_argument, NULL, OPTION_REDUCE_MEMORY_OVERHEADS}, + '\0', NULL, N_("Reduce memory overheads, possibly taking much longer"), TWO_DASHES }, { {"relax", no_argument, NULL, OPTION_RELAX}, '\0', NULL, N_("Relax branches on certain targets"), TWO_DASHES }, { {"retain-symbols-file", required_argument, NULL, @@ -447,8 +452,6 @@ static const struct ld_option ld_options[] = '\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 }, - { {"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) @@ -1224,9 +1227,24 @@ 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; + if (config.hash_table_size == 0) + config.hash_table_size = 1021; break; + + case OPTION_HASH_SIZE: + { + bfd_size_type new_size; + + new_size = strtoul (optarg, NULL, 0); + if (new_size) + config.hash_table_size = new_size; + else + einfo (_("%P%X: --hash-size needs a numeric argument\n")); + } + break; } } -- cgit v1.1