Replace the block_found global with explicit data-flow

As Pedro suggested on gdb-patches@ (see
https://sourceware.org/ml/gdb-patches/2015-05/msg00714.html), this
change makes symbol lookup functions return a structure that includes
both the symbol found and the block in which it was found.  This makes
it possible to get rid of the block_found global variable and thus makes
block hunting explicit.

gdb/

	* ada-exp.y (write_object_renaming): Replace struct
	ada_symbol_info with struct block_symbol.  Update field
	references accordingly.
	(block_lookup, select_possible_type_sym): Likewise.
	(find_primitive_type): Likewise.  Also update call to
	ada_lookup_symbol to extract the symbol itself.
	(write_var_or_type, write_name_assoc): Likewise.
	* ada-lang.h (struct ada_symbol_info): Remove.
	(ada_lookup_symbol_list): Replace struct ada_symbol_info with
	struct block_symbol.
	(ada_lookup_encoded_symbol, user_select_syms): Likewise.
	(ada_lookup_symbol): Return struct block_symbol instead of a
	mere symbol.
	* ada-lang.c (defns_collected): Replace struct ada_symbol_info
	with struct block_symbol.
	(resolve_subexp, ada_resolve_function, sort_choices,
	user_select_syms, is_nonfunction, add_defn_to_vec,
	num_defns_collected, defns_collected,
	symbols_are_identical_enums, remove_extra_symbols,
	remove_irrelevant_renamings, add_lookup_symbol_list_worker,
	ada_lookup_symbol_list, ada_iterate_over_symbols,
	ada_lookup_encoded_symbol, get_var_value): Likewise.
	(ada_lookup_symbol): Return a block_symbol instead of a mere
	symbol.  Replace struct ada_symbol_info with struct
	block_symbol.
	(ada_lookup_symbol_nonlocal): Likewise.
	(standard_lookup): Make block passing explicit through
	lookup_symbol_in_language.
	* ada-tasks.c (get_tcb_types_info): Update the calls to
	lookup_symbol_in_language to extract the mere symbol out of the
	returned value.
	(ada_tasks_inferior_data_sniffer): Likewise.
	* ax-gdb.c (gen_static_field): Likewise for the call to
	lookup_symbol.
	(gen_maybe_namespace_elt): Deal with struct symbol_in_block from
	lookup functions.
	(gen_expr): Likewise.
	* c-exp.y: Likewise.  Remove uses of block_found.
	(lex_one_token, classify_inner_name, c_print_token): Likewise.
	(classify_name): Likewise.  Rename the "sym" local variable to
	"bsym".
	* c-valprint.c (print_unpacked_pointer): Likewise.
	* compile/compile-c-symbols.c (convert_symbol_sym): Promote the
	"sym" parameter from struct symbol * to struct block_symbol.
	Use it to remove uses of block_found.  Deal with struct
	symbol_in_block from lookup functions.
	(gcc_convert_symbol): Likewise.  Update the call to
	convert_symbol_sym.
	* compile/compile-object-load.c (compile_object_load): Deal with
	struct symbol_in_block from lookup functions.
	* cp-namespace.c (cp_lookup_nested_symbol_1,
	cp_lookup_nested_symbol, cp_lookup_bare_symbol,
	cp_search_static_and_baseclasses,
	cp_lookup_symbol_in_namespace, cp_lookup_symbol_via_imports,
	cp_lookup_symbol_imports_or_template,
	cp_lookup_symbol_via_all_imports, cp_lookup_symbol_namespace,
	lookup_namespace_scope, cp_lookup_nonlocal,
	find_symbol_in_baseclass): Return struct symbol_in_block instead
	of mere symbols and deal with struct symbol_in_block from lookup
	functions.
	* cp-support.c (inspect_type, replace_typedefs,
	cp_lookup_rtti_type): Deal with struct symbol_in_block from
	lookup functions.
	* cp-support.h (cp_lookup_symbol_nonlocal,
	cp_lookup_symbol_from_namespace,
	cp_lookup_symbol_imports_or_template, cp_lookup_nested_symbol):
	Return struct symbol_in_block instead of mere symbols.
	* d-exp.y (d_type_from_name, d_module_from_name, push_variable,
	push_module_name):
	Deal with struct symbol_in_block from lookup functions.  Remove
	uses of block_found.
	* eval.c (evaluate_subexp_standard): Update call to
	cp_lookup_symbol_namespace.
	* f-exp.y: Deal with struct symbol_in_block from lookup
	functions.  Remove uses of block_found.
	(yylex): Likewise.
	* gdbtypes.c (lookup_typename, lookup_struct, lookup_union,
	lookup_enum, lookup_template_type, check_typedef): Deal with
	struct symbol_in_block from lookup functions.
	* guile/scm-frame.c (gdbscm_frame_read_var): Likewise.
	* guile/scm-symbol.c (gdbscm_lookup_symbol): Likewise.
	(gdbscm_lookup_global_symbol): Likewise.
	* gnu-v3-abi.c (gnuv3_get_typeid_type): Likewise.
	* go-exp.y: Likewise.  Remove uses of block_found.
	(package_name_p, classify_packaged_name, classify_name):
	Likewise.
	* infrun.c (insert_exception_resume_breakpoint): Likewise.
	* jv-exp.y (push_variable): Likewise.
	* jv-lang.c (java_lookup_class, get_java_object_type): Likewise.
	* language.c (language_bool_type): Likewise.
	* language.h (struct language_defn): Update
	la_lookup_symbol_nonlocal to return a struct symbol_in_block
	rather than a mere symbol.
	* linespec.c (find_label_symbols): Deal with struct
	symbol_in_block from lookup functions.
	* m2-exp.y: Likewise.  Remove uses of block_found.
	(yylex): Likewise.
	* mi/mi-cmd-stack.c (list_args_or_locals): Likewise.
	* objc-lang.c (lookup_struct_typedef, find_imps): Likewise.
	* p-exp.y: Likewise.  Remove uses of block_found.
	(yylex): Likewise.
	* p-valprint.c (pascal_val_print): Likewise.
	* parse.c (write_dollar_variable): Likewise.  Remove uses of
	block_found.
	* parser-defs.h (struct symtoken): Turn the SYM field into a
	struct symbol_in_block.
	* printcmd.c (address_info): Deal with struct symbol_in_block
	from lookup functions.
	* python/py-frame.c (frapy_read_var): Likewise.
	* python/py-symbol.c (gdbpy_lookup_symbol,
	gdbpy_lookup_global_symbol): Likewise.
	* skip.c (skip_function_command): Likewise.
	* solib-darwin.c (darwin_lookup_lib_symbol): Return a struct
	symbol_in_block instead of a mere symbol.
	* solib-spu.c (spu_lookup_lib_symbol): Likewise.
	* solib-svr4.c (elf_lookup_lib_symbol): Likewise.
	* solib.c (solib_global_lookup): Likewise.
	* solist.h (solib_global_lookup): Likewise.
	(struct target_so_ops): Update lookup_lib_global_symbol to
	return a struct symbol_in_block rather than a mere symbol.
	* source.c (select_source_symtab): Deal with struct
	symbol_in_block from lookup functions.
	* stack.c (print_frame_args, iterate_over_block_arg_vars):
	Likewise.
	* symfile.c (set_initial_language): Likewise.
	* symtab.c (SYMBOL_LOOKUP_FAILED): Turn into a struct
	symbol_in_block.
	(SYMBOL_LOOKUP_FAILED_P): New predicate as a macro.
	(struct symbol_cache_slot): Turn the FOUND field into a struct
	symbol_in_block.
	(block_found): Remove.
	(eq_symbol_entry): Update to deal with struct symbol_in_block in
	cache slots.
	(symbol_cache_lookup): Return a struct symbol_in_block rather
	than a mere symbol.
	(symbol_cache_mark_found): Add a BLOCK parameter to fill
	appropriately the cache slots.  Update callers.
	(symbol_cache_dump): Update cache slots handling to the type
	change.
	(lookup_symbol_in_language, lookup_symbol, lookup_language_this,
	lookup_symbol_aux, lookup_local_symbol,
	lookup_symbol_in_objfile, lookup_global_symbol_from_objfile,
	lookup_symbol_in_objfile_symtabs,
	lookup_symbol_in_objfile_from_linkage_name,
	lookup_symbol_via_quick_fns, basic_lookup_symbol_nonlocal,
	lookup_symbol_in_static_block, lookup_static_symbol,
	lookup_global_symbol):
	Return a struct symbol_in_block rather than a mere symbol.  Deal
	with struct symbol_in_block from other lookup functions.  Remove
	uses of block_found.
	(lookup_symbol_in_block): Remove uses of block_found.
	(struct global_sym_lookup_data): Turn the RESULT field into a
	struct symbol_in_block.
	(lookup_symbol_global_iterator_cb): Update references to the
	RESULT field.
	(search_symbols): Deal with struct symbol_in_block from lookup
	functions.
	* symtab.h (struct symbol_in_block): New structure.
	(block_found): Remove.
	(lookup_symbol_in_language, lookup_symbol,
	basic_lookup_symbol_nonlocal, lookup_symbol_in_static_block,
	looku_static_symbol, lookup_global_symbol,
	lookup_symbol_in_block, lookup_language_this,
	lookup_global_symbol_from_objfile): Return a struct
	symbol_in_block rather than just a mere symbol.  Update comments
	to remove mentions of block_found.
	* valops.c (find_function_in_inferior,
	value_struct_elt_for_reference, value_maybe_namespace_elt,
	value_of_this):  Deal with struct symbol_in_block from lookup
	functions.
	* value.c (value_static_field, value_fn_field): Likewise.

2 files changed, 13 insertions, 15 deletions

diff --git a/gdb/compile/compile-c-symbols.c b/gdb/compile/compile-c-symbols.c
index 68d38ba..21ce655 100644
--- a/gdb/compile/compile-c-symbols.c
+++ b/gdb/compile/compile-c-symbols.c
@@ -304,13 +304,11 @@ convert_one_symbol (struct compile_c_instance *context,
 
 static void
 convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
-		    struct symbol *sym, domain_enum domain)
+		    struct block_symbol sym, domain_enum domain)
 {
-  const struct block *static_block, *found_block;
+  const struct block *static_block;
   int is_local_symbol;
 
-  found_block = block_found;
-
   /* If we found a symbol and it is not in the  static or global
      scope, then we should first convert any static or global scope
      symbol of the same name.  This lets this unusual case work:
@@ -323,24 +321,24 @@ convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
      }
   */
 
-  static_block = block_static_block (found_block);
+  static_block = block_static_block (sym.block);
   /* STATIC_BLOCK is NULL if FOUND_BLOCK is the global block.  */
-  is_local_symbol = (found_block != static_block && static_block != NULL);
+  is_local_symbol = (sym.block != static_block && static_block != NULL);
   if (is_local_symbol)
     {
-      struct symbol *global_sym;
+      struct block_symbol global_sym;
 
       global_sym = lookup_symbol (identifier, NULL, domain, NULL);
       /* If the outer symbol is in the static block, we ignore it, as
 	 it cannot be referenced.  */
-      if (global_sym != NULL
-	  && block_found != block_static_block (block_found))
+      if (global_sym.symbol != NULL
+	  && global_sym.block != block_static_block (global_sym.block))
 	{
 	  if (compile_debug)
 	    fprintf_unfiltered (gdb_stdlog,
 				"gcc_convert_symbol \"%s\": global symbol\n",
 				identifier);
-	  convert_one_symbol (context, global_sym, 1, 0);
+	  convert_one_symbol (context, global_sym.symbol, 1, 0);
 	}
     }
 
@@ -348,7 +346,7 @@ convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
     fprintf_unfiltered (gdb_stdlog,
 			"gcc_convert_symbol \"%s\": local symbol\n",
 			identifier);
-  convert_one_symbol (context, sym, 0, is_local_symbol);
+  convert_one_symbol (context, sym.symbol, 0, is_local_symbol);
 }
 
 /* Convert a minimal symbol to its gcc form.  CONTEXT is the compiler
@@ -444,10 +442,10 @@ gcc_convert_symbol (void *datum,
      is to simply emit a gcc error.  */
   TRY
     {
-      struct symbol *sym;
+      struct block_symbol sym;
 
       sym = lookup_symbol (identifier, context->base.block, domain, NULL);
-      if (sym != NULL)
+      if (sym.symbol != NULL)
 	{
 	  convert_symbol_sym (context, identifier, sym, domain);
 	  found = 1;
@@ -495,7 +493,7 @@ gcc_symbol_address (void *datum, struct gcc_c_context *gcc_context,
       struct symbol *sym;
 
       /* We only need global functions here.  */
-      sym = lookup_symbol (identifier, NULL, VAR_DOMAIN, NULL);
+      sym = lookup_symbol (identifier, NULL, VAR_DOMAIN, NULL).symbol;
       if (sym != NULL && SYMBOL_CLASS (sym) == LOC_BLOCK)
 	{
 	  if (compile_debug)
diff --git a/gdb/compile/compile-object-load.c b/gdb/compile/compile-object-load.c
index 162227a..16775ab 100644
--- a/gdb/compile/compile-object-load.c
+++ b/gdb/compile/compile-object-load.c
@@ -676,7 +676,7 @@ compile_object_load (const char *object_file, const char *source_file,
 
   func_sym = lookup_global_symbol_from_objfile (objfile,
 						GCC_FE_WRAPPER_FUNCTION,
-						VAR_DOMAIN);
+						VAR_DOMAIN).symbol;
   if (func_sym == NULL)
     error (_("Cannot find function \"%s\" in compiled module \"%s\"."),
 	   GCC_FE_WRAPPER_FUNCTION, objfile_name (objfile));