More block constification

I noticed that there are still many places referring to non-const
blocks.  This constifies all the remaining ones that I found that
could be constified.

In a few spots, this search found unused variables or fields.  I
removed these.  I've also removed some unnecessary casts to
"struct block *".

gdb/ChangeLog
2019-03-24  Tom Tromey  <tom@tromey.com>

	* c-exp.y (typebase): Remove casts.
	* gdbtypes.c (lookup_unsigned_typename, )
	(lookup_signed_typename): Remove cast.
	* eval.c (parse_to_comma_and_eval): Remove cast.
	* parse.c (write_dollar_variable): Remove cast.
	* block.h (struct block) <superblock>: Now const.
	* symfile-debug.c (debug_qf_map_matching_symbols): Update.
	* psymtab.c (psym_map_matching_symbols): Make "block" const.
	(map_block): Make "block" const.
	* symfile.h (struct quick_symbol_functions)
	<map_matching_symbols>: Constify block argument to "callback".
	* symtab.c (basic_lookup_transparent_type_quick): Make "block"
	const.
	(find_pc_sect_compunit_symtab): Make "b" const.
	(find_symbol_at_address): Likewise.
	(search_symbols): Likewise.
	* dwarf2read.c (dw2_lookup_symbol): Make "block" const.
	(dw2_debug_names_lookup_symbol): Likewise.
	(dw2_map_matching_symbols): Update.
	* p-valprint.c (pascal_val_print): Remove "block".
	* ada-lang.c (ada_add_global_exceptions): Make "b" const.
	(aux_add_nonlocal_symbols): Make "block" const.
	(resolve_subexp): Remove cast.
	* linespec.c (iterate_over_all_matching_symtabs): Make "block"
	const.
	(iterate_over_file_blocks): Likewise.
	* f-exp.y (%union) <bval>: Remove.
	* coffread.c (patch_opaque_types): Make "b" const.
	* spu-tdep.c (spu_catch_start): Make "block" const.
	* c-valprint.c (print_unpacked_pointer): Remove "block".
	* symmisc.c (dump_symtab_1): Make "b" const.
	(block_depth): Make "block" const.
	* d-exp.y (%union) <bval>: Remove.
	* cp-support.h (cp_lookup_rtti_type): Update.
	* cp-support.c (cp_lookup_rtti_type): Make "block" const.
	* psymtab.c (psym_lookup_symbol): Make "block" const.
	(maintenance_check_psymtabs): Make "b" const.
	* python/py-framefilter.c (extract_sym): Make "sym_block" const.
	(enumerate_locals, enumerate_args): Update.
	* python/py-symtab.c (stpy_global_block): Make "block" const.
	(stpy_static_block): Likewise.
	* inline-frame.c (block_starting_point_at): Make "new_block"
	const.
	* block.c (find_block_in_blockvector): Make return type const.
	(blockvector_for_pc_sect): Make "b" const.
	(find_block_in_blockvector): Make "b" const.

1 files changed, 4 insertions, 4 deletions

diff --git a/gdb/block.c b/gdb/block.c
index 3192b33..63c7d9f 100644
--- a/gdb/block.c
+++ b/gdb/block.c
@@ -131,16 +131,16 @@ block_inlined_p (const struct block *bl)
 /* A helper function that checks whether PC is in the blockvector BL.
    It returns the containing block if there is one, or else NULL.  */
 
-static struct block *
+static const struct block *
 find_block_in_blockvector (const struct blockvector *bl, CORE_ADDR pc)
 {
-  struct block *b;
+  const struct block *b;
   int bot, top, half;
 
   /* If we have an addrmap mapping code addresses to blocks, then use
      that.  */
   if (BLOCKVECTOR_MAP (bl))
-    return (struct block *) addrmap_find (BLOCKVECTOR_MAP (bl), pc);
+    return (const struct block *) addrmap_find (BLOCKVECTOR_MAP (bl), pc);
 
   /* Otherwise, use binary search to find the last block that starts
      before PC.
@@ -186,7 +186,7 @@ blockvector_for_pc_sect (CORE_ADDR pc, struct obj_section *section,
 			 struct compunit_symtab *cust)
 {
   const struct blockvector *bl;
-  struct block *b;
+  const struct block *b;
 
   if (cust == NULL)
     {