* 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, 28 insertions, 3 deletions

diff --git a/ld/ld.h b/ld/ld.h
index dde4cfe234..1061c35968 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;