* 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.

1 files changed, 6 insertions, 0 deletions

diff --git a/ld/NEWS b/ld/NEWS
index cec229be64..a33c6dc70c 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.