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.

1 files changed, 156 insertions, 150 deletions

diff --git a/gdb/symtab.c b/gdb/symtab.c
index decc5a9..8aeabe86 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -68,19 +68,20 @@ static void rbreak_command (char *, int);
 
 static int find_line_common (struct linetable *, int, int *, int);
 
-static struct symbol *lookup_symbol_aux (const char *name,
-					 const struct block *block,
-					 const domain_enum domain,
-					 enum language language,
-					 struct field_of_this_result *);
+static struct block_symbol
+  lookup_symbol_aux (const char *name,
+		     const struct block *block,
+		     const domain_enum domain,
+		     enum language language,
+		     struct field_of_this_result *);
 
 static
-struct symbol *lookup_local_symbol (const char *name,
-				    const struct block *block,
-				    const domain_enum domain,
-				    enum language language);
+struct block_symbol lookup_local_symbol (const char *name,
+					 const struct block *block,
+					 const domain_enum domain,
+					 enum language language);
 
-static struct symbol *
+static struct block_symbol
   lookup_symbol_in_objfile (struct objfile *objfile, int block_index,
 			    const char *name, const domain_enum domain);
 
@@ -121,7 +122,9 @@ static const struct program_space_data *symbol_cache_key;
 
 /* symbol_cache_lookup returns this if a previous lookup failed to find the
    symbol in any objfile.  */
-#define SYMBOL_LOOKUP_FAILED ((struct symbol *) 1)
+#define SYMBOL_LOOKUP_FAILED \
+ ((struct block_symbol) {(struct symbol *) 1, NULL})
+#define SYMBOL_LOOKUP_FAILED_P(SIB) (SIB.symbol == (struct symbol *) 1)
 
 /* Recording lookups that don't find the symbol is just as important, if not
    more so, than recording found symbols.  */
@@ -157,7 +160,7 @@ struct symbol_cache_slot
 
   union
   {
-    struct symbol *found;
+    struct block_symbol found;
     struct
     {
       char *name;
@@ -243,12 +246,6 @@ multiple_symbols_select_mode (void)
   return multiple_symbols_mode;
 }
 
-/* Block in which the most recently searched-for symbol was found.
-   Might be better to make this a parameter to lookup_symbol and
-   value_of_this.  */
-
-const struct block *block_found;
-
 /* Return the name of a domain_enum.  */
 
 const char *
@@ -1208,8 +1205,8 @@ eq_symbol_entry (const struct symbol_cache_slot *slot,
     }
   else
     {
-      slot_name = SYMBOL_SEARCH_NAME (slot->value.found);
-      slot_domain = SYMBOL_DOMAIN (slot->value.found);
+      slot_name = SYMBOL_SEARCH_NAME (slot->value.found.symbol);
+      slot_domain = SYMBOL_DOMAIN (slot->value.found.symbol);
     }
 
   /* NULL names match.  */
@@ -1240,7 +1237,7 @@ eq_symbol_entry (const struct symbol_cache_slot *slot,
 	}
       else
 	{
-	  struct symbol *sym = slot->value.found;
+	  struct symbol *sym = slot->value.found.symbol;
 
 	  if (strcmp_iw (slot_name, name) != 0)
 	    return 0;
@@ -1398,7 +1395,7 @@ set_symbol_cache_size_handler (char *args, int from_tty,
    set to the cache and slot of the symbol to save the result of a full lookup
    attempt.  */
 
-static struct symbol *
+static struct block_symbol
 symbol_cache_lookup (struct symbol_cache *cache,
 		     struct objfile *objfile_context, int block,
 		     const char *name, domain_enum domain,
@@ -1417,7 +1414,7 @@ symbol_cache_lookup (struct symbol_cache *cache,
     {
       *bsc_ptr = NULL;
       *slot_ptr = NULL;
-      return NULL;
+      return (struct block_symbol) {NULL, NULL};
     }
 
   hash = hash_symbol_entry (objfile_context, name, domain);
@@ -1451,7 +1448,7 @@ symbol_cache_lookup (struct symbol_cache *cache,
 			  name, domain_name (domain));
     }
   ++bsc->misses;
-  return NULL;
+  return (struct block_symbol) {NULL, NULL};
 }
 
 /* Clear out SLOT.  */
@@ -1473,7 +1470,8 @@ static void
 symbol_cache_mark_found (struct block_symbol_cache *bsc,
 			 struct symbol_cache_slot *slot,
 			 struct objfile *objfile_context,
-			 struct symbol *symbol)
+			 struct symbol *symbol,
+			 const struct block *block)
 {
   if (bsc == NULL)
     return;
@@ -1484,7 +1482,8 @@ symbol_cache_mark_found (struct block_symbol_cache *bsc,
     }
   slot->state = SYMBOL_SLOT_FOUND;
   slot->objfile_context = objfile_context;
-  slot->value.found = symbol;
+  slot->value.found.symbol = symbol;
+  slot->value.found.block = block;
 }
 
 /* Mark symbol NAME, DOMAIN as not found in SLOT.
@@ -1597,11 +1596,16 @@ symbol_cache_dump (const struct symbol_cache *cache)
 			       domain_name (slot->value.not_found.domain));
 	      break;
 	    case SYMBOL_SLOT_FOUND:
-	      printf_filtered ("  [%4u] = %s, %s %s\n", i,
-			       host_address_to_string (slot->objfile_context),
-			       SYMBOL_PRINT_NAME (slot->value.found),
-			       domain_name (SYMBOL_DOMAIN (slot->value.found)));
-	      break;
+	      {
+		struct symbol *found = slot->value.found.symbol;
+		const struct objfile *context = slot->objfile_context;
+
+		printf_filtered ("  [%4u] = %s, %s %s\n", i,
+				 host_address_to_string (context),
+				 SYMBOL_PRINT_NAME (found),
+				 domain_name (SYMBOL_DOMAIN (found)));
+		break;
+	      }
 	    }
 	}
     }
@@ -1945,13 +1949,13 @@ demangle_for_lookup (const char *name, enum language lang,
    variable and thus can probably assume it will never hit the C++
    code).  */
 
-struct symbol *
+struct block_symbol
 lookup_symbol_in_language (const char *name, const struct block *block,
 			   const domain_enum domain, enum language lang,
 			   struct field_of_this_result *is_a_field_of_this)
 {
   const char *modified_name;
-  struct symbol *returnval;
+  struct block_symbol returnval;
   struct cleanup *cleanup = demangle_for_lookup (name, lang, &modified_name);
 
   returnval = lookup_symbol_aux (modified_name, block, domain, lang,
@@ -1963,7 +1967,7 @@ lookup_symbol_in_language (const char *name, const struct block *block,
 
 /* See symtab.h.  */
 
-struct symbol *
+struct block_symbol
 lookup_symbol (const char *name, const struct block *block,
 	       domain_enum domain,
 	       struct field_of_this_result *is_a_field_of_this)
@@ -1975,12 +1979,12 @@ lookup_symbol (const char *name, const struct block *block,
 
 /* See symtab.h.  */
 
-struct symbol *
+struct block_symbol
 lookup_language_this (const struct language_defn *lang,
 		      const struct block *block)
 {
   if (lang->la_name_of_this == NULL || block == NULL)
-    return NULL;
+    return (struct block_symbol) {NULL, NULL};
 
   if (symbol_lookup_debug > 1)
     {
@@ -2006,8 +2010,7 @@ lookup_language_this (const struct language_defn *lang,
 				  host_address_to_string (sym),
 				  host_address_to_string (block));
 	    }
-	  block_found = block;
-	  return sym;
+	  return (struct block_symbol) {sym, block};
 	}
       if (BLOCK_FUNCTION (block))
 	break;
@@ -2016,7 +2019,7 @@ lookup_language_this (const struct language_defn *lang,
 
   if (symbol_lookup_debug > 1)
     fprintf_unfiltered (gdb_stdlog, " = NULL\n");
-  return NULL;
+  return (struct block_symbol) {NULL, NULL};
 }
 
 /* Given TYPE, a structure/union,
@@ -2067,12 +2070,12 @@ check_field (struct type *type, const char *name,
 /* Behave like lookup_symbol except that NAME is the natural name
    (e.g., demangled name) of the symbol that we're looking for.  */
 
-static struct symbol *
+static struct block_symbol
 lookup_symbol_aux (const char *name, const struct block *block,
 		   const domain_enum domain, enum language language,
 		   struct field_of_this_result *is_a_field_of_this)
 {
-  struct symbol *sym;
+  struct block_symbol result;
   const struct language_defn *langdef;
 
   if (symbol_lookup_debug)
@@ -2087,13 +2090,6 @@ lookup_symbol_aux (const char *name, const struct block *block,
 			  domain_name (domain), language_str (language));
     }
 
-  /* Initialize block_found so that the language la_lookup_symbol_nonlocal
-     routines don't have to set it (to NULL) if a primitive type is found.
-     We do this early so that block_found is also NULL if no symbol is
-     found (though this is not part of the API, and callers cannot assume
-     this).  */
-  block_found = NULL;
-
   /* Make sure we do something sensible with is_a_field_of_this, since
      the callers that set this parameter to some non-null value will
      certainly use it later.  If we don't set it, the contents of
@@ -2104,15 +2100,15 @@ lookup_symbol_aux (const char *name, const struct block *block,
   /* Search specified block and its superiors.  Don't search
      STATIC_BLOCK or GLOBAL_BLOCK.  */
 
-  sym = lookup_local_symbol (name, block, domain, language);
-  if (sym != NULL)
+  result = lookup_local_symbol (name, block, domain, language);
+  if (result.symbol != NULL)
     {
       if (symbol_lookup_debug)
 	{
 	  fprintf_unfiltered (gdb_stdlog, "lookup_symbol_aux (...) = %s\n",
-			      host_address_to_string (sym));
+			      host_address_to_string (result.symbol));
 	}
-      return sym;
+      return result;
     }
 
   /* If requested to do so by the caller and if appropriate for LANGUAGE,
@@ -2125,11 +2121,11 @@ lookup_symbol_aux (const char *name, const struct block *block,
      means.  */
   if (is_a_field_of_this != NULL && domain != STRUCT_DOMAIN)
     {
-      struct symbol *sym = lookup_language_this (langdef, block);
+      result = lookup_language_this (langdef, block);
 
-      if (sym)
+      if (result.symbol)
 	{
-	  struct type *t = sym->type;
+	  struct type *t = result.symbol->type;
 
 	  /* I'm not really sure that type of this can ever
 	     be typedefed; just be safe.  */
@@ -2150,7 +2146,7 @@ lookup_symbol_aux (const char *name, const struct block *block,
 		  fprintf_unfiltered (gdb_stdlog,
 				      "lookup_symbol_aux (...) = NULL\n");
 		}
-	      return NULL;
+	      return (struct block_symbol) {NULL, NULL};
 	    }
 	}
     }
@@ -2158,33 +2154,35 @@ lookup_symbol_aux (const char *name, const struct block *block,
   /* Now do whatever is appropriate for LANGUAGE to look
      up static and global variables.  */
 
-  sym = langdef->la_lookup_symbol_nonlocal (langdef, name, block, domain);
-  if (sym != NULL)
+  result = langdef->la_lookup_symbol_nonlocal (langdef, name, block, domain);
+  if (result.symbol != NULL)
     {
       if (symbol_lookup_debug)
 	{
 	  fprintf_unfiltered (gdb_stdlog, "lookup_symbol_aux (...) = %s\n",
-			      host_address_to_string (sym));
+			      host_address_to_string (result.symbol));
 	}
-      return sym;
+      return result;
     }
 
   /* Now search all static file-level symbols.  Not strictly correct,
      but more useful than an error.  */
 
-  sym = lookup_static_symbol (name, domain);
+  result = lookup_static_symbol (name, domain);
   if (symbol_lookup_debug)
     {
       fprintf_unfiltered (gdb_stdlog, "lookup_symbol_aux (...) = %s\n",
-			  sym != NULL ? host_address_to_string (sym) : "NULL");
+			  result.symbol != NULL
+			    ? host_address_to_string (result.symbol)
+			    : "NULL");
     }
-  return sym;
+  return result;
 }
 
 /* Check to see if the symbol is defined in BLOCK or its superiors.
    Don't search STATIC_BLOCK or GLOBAL_BLOCK.  */
 
-static struct symbol *
+static struct block_symbol
 lookup_local_symbol (const char *name, const struct block *block,
 		     const domain_enum domain,
 		     enum language language)
@@ -2196,19 +2194,21 @@ lookup_local_symbol (const char *name, const struct block *block,
   /* Check if either no block is specified or it's a global block.  */
 
   if (static_block == NULL)
-    return NULL;
+    return (struct block_symbol) {NULL, NULL};
 
   while (block != static_block)
     {
       sym = lookup_symbol_in_block (name, block, domain);
       if (sym != NULL)
-	return sym;
+	return (struct block_symbol) {sym, block};
 
       if (language == language_cplus || language == language_fortran)
         {
-          sym = cp_lookup_symbol_imports_or_template (scope, name, block,
-						      domain);
-          if (sym != NULL)
+          struct block_symbol sym
+	    = cp_lookup_symbol_imports_or_template (scope, name, block,
+						    domain);
+
+          if (sym.symbol != NULL)
             return sym;
         }
 
@@ -2219,7 +2219,7 @@ lookup_local_symbol (const char *name, const struct block *block,
 
   /* We've reached the end of the function without finding a result.  */
 
-  return NULL;
+  return (struct block_symbol) {NULL, NULL};
 }
 
 /* See symtab.h.  */
@@ -2275,7 +2275,6 @@ lookup_symbol_in_block (const char *name, const struct block *block,
 	  fprintf_unfiltered (gdb_stdlog, " = %s\n",
 			      host_address_to_string (sym));
 	}
-      block_found = block;
       return fixup_symbol_section (sym, NULL);
     }
 
@@ -2286,7 +2285,7 @@ lookup_symbol_in_block (const char *name, const struct block *block,
 
 /* See symtab.h.  */
 
-struct symbol *
+struct block_symbol
 lookup_global_symbol_from_objfile (struct objfile *main_objfile,
 				   const char *name,
 				   const domain_enum domain)
@@ -2297,14 +2296,14 @@ lookup_global_symbol_from_objfile (struct objfile *main_objfile,
        objfile;
        objfile = objfile_separate_debug_iterate (main_objfile, objfile))
     {
-      struct symbol *sym = lookup_symbol_in_objfile (objfile, GLOBAL_BLOCK,
-						     name, domain);
+      struct block_symbol result
+        = lookup_symbol_in_objfile (objfile, GLOBAL_BLOCK, name, domain);
 
-      if (sym != NULL)
-	return sym;
+      if (result.symbol != NULL)
+	return result;
     }
 
-  return NULL;
+  return (struct block_symbol) {NULL, NULL};
 }
 
 /* Check to see if the symbol is defined in one of the OBJFILE's
@@ -2312,7 +2311,7 @@ lookup_global_symbol_from_objfile (struct objfile *main_objfile,
    depending on whether or not we want to search global symbols or
    static symbols.  */
 
-static struct symbol *
+static struct block_symbol
 lookup_symbol_in_objfile_symtabs (struct objfile *objfile, int block_index,
 				  const char *name, const domain_enum domain)
 {
@@ -2334,27 +2333,29 @@ lookup_symbol_in_objfile_symtabs (struct objfile *objfile, int block_index,
     {
       const struct blockvector *bv;
       const struct block *block;
-      struct symbol *sym;
+      struct block_symbol result;
 
       bv = COMPUNIT_BLOCKVECTOR (cust);
       block = BLOCKVECTOR_BLOCK (bv, block_index);
-      sym = block_lookup_symbol_primary (block, name, domain);
-      if (sym)
+      result.symbol = block_lookup_symbol_primary (block, name, domain);
+      result.block = block;
+      if (result.symbol != NULL)
 	{
 	  if (symbol_lookup_debug > 1)
 	    {
 	      fprintf_unfiltered (gdb_stdlog, " = %s (block %s)\n",
-				  host_address_to_string (sym),
+				  host_address_to_string (result.symbol),
 				  host_address_to_string (block));
 	    }
-	  block_found = block;
-	  return fixup_symbol_section (sym, objfile);
+	  result.symbol = fixup_symbol_section (result.symbol, objfile);
+	  return result;
+
 	}
     }
 
   if (symbol_lookup_debug > 1)
     fprintf_unfiltered (gdb_stdlog, " = NULL\n");
-  return NULL;
+  return (struct block_symbol) {NULL, NULL};
 }
 
 /* Wrapper around lookup_symbol_in_objfile_symtabs for search_symbols.
@@ -2366,7 +2367,7 @@ lookup_symbol_in_objfile_symtabs (struct objfile *objfile, int block_index,
    different.  Here we're called from search_symbols where it will only
    call us for the the objfile that contains a matching minsym.  */
 
-static struct symbol *
+static struct block_symbol
 lookup_symbol_in_objfile_from_linkage_name (struct objfile *objfile,
 					    const char *linkage_name,
 					    domain_enum domain)
@@ -2386,22 +2387,22 @@ lookup_symbol_in_objfile_from_linkage_name (struct objfile *objfile,
        cur_objfile;
        cur_objfile = objfile_separate_debug_iterate (main_objfile, cur_objfile))
     {
-      struct symbol *sym;
+      struct block_symbol result;
 
-      sym = lookup_symbol_in_objfile_symtabs (cur_objfile, GLOBAL_BLOCK,
-					      modified_name, domain);
-      if (sym == NULL)
-	sym = lookup_symbol_in_objfile_symtabs (cur_objfile, STATIC_BLOCK,
-						modified_name, domain);
-      if (sym != NULL)
+      result = lookup_symbol_in_objfile_symtabs (cur_objfile, GLOBAL_BLOCK,
+						 modified_name, domain);
+      if (result.symbol == NULL)
+	result = lookup_symbol_in_objfile_symtabs (cur_objfile, STATIC_BLOCK,
+						   modified_name, domain);
+      if (result.symbol != NULL)
 	{
 	  do_cleanups (cleanup);
-	  return sym;
+	  return result;
 	}
     }
 
   do_cleanups (cleanup);
-  return NULL;
+  return (struct block_symbol) {NULL, NULL};
 }
 
 /* A helper function that throws an exception when a symbol was found
@@ -2424,17 +2425,17 @@ Internal: %s symbol `%s' found in %s psymtab but not in symtab.\n\
 /* A helper function for various lookup routines that interfaces with
    the "quick" symbol table functions.  */
 
-static struct symbol *
+static struct block_symbol
 lookup_symbol_via_quick_fns (struct objfile *objfile, int block_index,
 			     const char *name, const domain_enum domain)
 {
   struct compunit_symtab *cust;
   const struct blockvector *bv;
   const struct block *block;
-  struct symbol *sym;
+  struct block_symbol result;
 
   if (!objfile->sf)
-    return NULL;
+    return (struct block_symbol) {NULL, NULL};
 
   if (symbol_lookup_debug > 1)
     {
@@ -2454,36 +2455,37 @@ lookup_symbol_via_quick_fns (struct objfile *objfile, int block_index,
 	  fprintf_unfiltered (gdb_stdlog,
 			      "lookup_symbol_via_quick_fns (...) = NULL\n");
 	}
-      return NULL;
+      return (struct block_symbol) {NULL, NULL};
     }
 
   bv = COMPUNIT_BLOCKVECTOR (cust);
   block = BLOCKVECTOR_BLOCK (bv, block_index);
-  sym = block_lookup_symbol (block, name, domain);
-  if (!sym)
+  result.symbol = block_lookup_symbol (block, name, domain);
+  if (result.symbol == NULL)
     error_in_psymtab_expansion (block_index, name, cust);
 
   if (symbol_lookup_debug > 1)
     {
       fprintf_unfiltered (gdb_stdlog,
 			  "lookup_symbol_via_quick_fns (...) = %s (block %s)\n",
-			  host_address_to_string (sym),
+			  host_address_to_string (result.symbol),
 			  host_address_to_string (block));
     }
 
-  block_found = block;
-  return fixup_symbol_section (sym, objfile);
+  result.symbol = fixup_symbol_section (result.symbol, objfile);
+  result.block = block;
+  return result;
 }
 
 /* See symtab.h.  */
 
-struct symbol *
+struct block_symbol
 basic_lookup_symbol_nonlocal (const struct language_defn *langdef,
 			      const char *name,
 			      const struct block *block,
 			      const domain_enum domain)
 {
-  struct symbol *sym;
+  struct block_symbol result;
 
   /* NOTE: carlton/2003-05-19: The comments below were written when
      this (or what turned into this) was part of lookup_symbol_aux;
@@ -2517,9 +2519,9 @@ basic_lookup_symbol_nonlocal (const struct language_defn *langdef,
      the current objfile.  Searching the current objfile first is useful
      for both matching user expectations as well as performance.  */
 
-  sym = lookup_symbol_in_static_block (name, block, domain);
-  if (sym != NULL)
-    return sym;
+  result = lookup_symbol_in_static_block (name, block, domain);
+  if (result.symbol != NULL)
+    return result;
 
   /* If we didn't find a definition for a builtin type in the static block,
      search for it now.  This is actually the right thing to do and can be
@@ -2535,9 +2537,11 @@ basic_lookup_symbol_nonlocal (const struct language_defn *langdef,
 	gdbarch = target_gdbarch ();
       else
 	gdbarch = block_gdbarch (block);
-      sym = language_lookup_primitive_type_as_symbol (langdef, gdbarch, name);
-      if (sym != NULL)
-	return sym;
+      result.symbol = language_lookup_primitive_type_as_symbol (langdef,
+								gdbarch, name);
+      result.block = NULL;
+      if (result.symbol != NULL)
+	return result;
     }
 
   return lookup_global_symbol (name, block, domain);
@@ -2545,7 +2549,7 @@ basic_lookup_symbol_nonlocal (const struct language_defn *langdef,
 
 /* See symtab.h.  */
 
-struct symbol *
+struct block_symbol
 lookup_symbol_in_static_block (const char *name,
 			       const struct block *block,
 			       const domain_enum domain)
@@ -2554,7 +2558,7 @@ lookup_symbol_in_static_block (const char *name,
   struct symbol *sym;
 
   if (static_block == NULL)
-    return NULL;
+    return (struct block_symbol) {NULL, NULL};
 
   if (symbol_lookup_debug)
     {
@@ -2576,7 +2580,7 @@ lookup_symbol_in_static_block (const char *name,
 			  "lookup_symbol_in_static_block (...) = %s\n",
 			  sym != NULL ? host_address_to_string (sym) : "NULL");
     }
-  return sym;
+  return (struct block_symbol) {sym, static_block};
 }
 
 /* Perform the standard symbol lookup of NAME in OBJFILE:
@@ -2584,11 +2588,11 @@ lookup_symbol_in_static_block (const char *name,
    2) Search the "quick" symtabs (partial or .gdb_index).
    BLOCK_INDEX is one of GLOBAL_BLOCK or STATIC_BLOCK.  */
 
-static struct symbol *
+static struct block_symbol
 lookup_symbol_in_objfile (struct objfile *objfile, int block_index,
 			  const char *name, const domain_enum domain)
 {
-  struct symbol *result;
+  struct block_symbol result;
 
   if (symbol_lookup_debug)
     {
@@ -2602,14 +2606,14 @@ lookup_symbol_in_objfile (struct objfile *objfile, int block_index,
 
   result = lookup_symbol_in_objfile_symtabs (objfile, block_index,
 					     name, domain);
-  if (result != NULL)
+  if (result.symbol != NULL)
     {
       if (symbol_lookup_debug)
 	{
 	  fprintf_unfiltered (gdb_stdlog,
 			      "lookup_symbol_in_objfile (...) = %s"
 			      " (in symtabs)\n",
-			      host_address_to_string (result));
+			      host_address_to_string (result.symbol));
 	}
       return result;
     }
@@ -2620,22 +2624,22 @@ lookup_symbol_in_objfile (struct objfile *objfile, int block_index,
     {
       fprintf_unfiltered (gdb_stdlog,
 			  "lookup_symbol_in_objfile (...) = %s%s\n",
-			  result != NULL
-			  ? host_address_to_string (result)
+			  result.symbol != NULL
+			  ? host_address_to_string (result.symbol)
 			  : "NULL",
-			  result != NULL ? " (via quick fns)" : "");
+			  result.symbol != NULL ? " (via quick fns)" : "");
     }
   return result;
 }
 
 /* See symtab.h.  */
 
-struct symbol *
+struct block_symbol
 lookup_static_symbol (const char *name, const domain_enum domain)
 {
   struct symbol_cache *cache = get_symbol_cache (current_program_space);
   struct objfile *objfile;
-  struct symbol *result;
+  struct block_symbol result;
   struct block_symbol_cache *bsc;
   struct symbol_cache_slot *slot;
 
@@ -2643,27 +2647,28 @@ lookup_static_symbol (const char *name, const domain_enum domain)
      NULL for OBJFILE_CONTEXT.  */
   result = symbol_cache_lookup (cache, NULL, STATIC_BLOCK, name, domain,
 				&bsc, &slot);
-  if (result != NULL)
+  if (result.symbol != NULL)
     {
-      if (result == SYMBOL_LOOKUP_FAILED)
-	return NULL;
+      if (SYMBOL_LOOKUP_FAILED_P (result))
+	return (struct block_symbol) {NULL, NULL};
       return result;
     }
 
   ALL_OBJFILES (objfile)
     {
       result = lookup_symbol_in_objfile (objfile, STATIC_BLOCK, name, domain);
-      if (result != NULL)
+      if (result.symbol != NULL)
 	{
 	  /* Still pass NULL for OBJFILE_CONTEXT here.  */
-	  symbol_cache_mark_found (bsc, slot, NULL, result);
+	  symbol_cache_mark_found (bsc, slot, NULL, result.symbol,
+				   result.block);
 	  return result;
 	}
     }
 
   /* Still pass NULL for OBJFILE_CONTEXT here.  */
   symbol_cache_mark_not_found (bsc, slot, NULL, name, domain);
-  return NULL;
+  return (struct block_symbol) {NULL, NULL};
 }
 
 /* Private data to be used with lookup_symbol_global_iterator_cb.  */
@@ -2677,8 +2682,8 @@ struct global_sym_lookup_data
   domain_enum domain;
 
   /* The field where the callback should store the symbol if found.
-     It should be initialized to NULL before the search is started.  */
-  struct symbol *result;
+     It should be initialized to {NULL, NULL} before the search is started.  */
+  struct block_symbol result;
 };
 
 /* A callback function for gdbarch_iterate_over_objfiles_in_search_order.
@@ -2693,25 +2698,26 @@ lookup_symbol_global_iterator_cb (struct objfile *objfile,
   struct global_sym_lookup_data *data =
     (struct global_sym_lookup_data *) cb_data;
 
-  gdb_assert (data->result == NULL);
+  gdb_assert (data->result.symbol == NULL
+	      && data->result.block == NULL);
 
   data->result = lookup_symbol_in_objfile (objfile, GLOBAL_BLOCK,
 					   data->name, data->domain);
 
   /* If we found a match, tell the iterator to stop.  Otherwise,
      keep going.  */
-  return (data->result != NULL);
+  return (data->result.symbol != NULL);
 }
 
 /* See symtab.h.  */
 
-struct symbol *
+struct block_symbol
 lookup_global_symbol (const char *name,
 		      const struct block *block,
 		      const domain_enum domain)
 {
   struct symbol_cache *cache = get_symbol_cache (current_program_space);
-  struct symbol *sym;
+  struct block_symbol result;
   struct objfile *objfile;
   struct global_sym_lookup_data lookup_data;
   struct block_symbol_cache *bsc;
@@ -2721,21 +2727,21 @@ lookup_global_symbol (const char *name,
 
   /* First see if we can find the symbol in the cache.
      This works because we use the current objfile to qualify the lookup.  */
-  sym = symbol_cache_lookup (cache, objfile, GLOBAL_BLOCK, name, domain,
-			     &bsc, &slot);
-  if (sym != NULL)
+  result = symbol_cache_lookup (cache, objfile, GLOBAL_BLOCK, name, domain,
+				&bsc, &slot);
+  if (result.symbol != NULL)
     {
-      if (sym == SYMBOL_LOOKUP_FAILED)
-	return NULL;
-      return sym;
+      if (SYMBOL_LOOKUP_FAILED_P (result))
+	return (struct block_symbol) {NULL, NULL};
+      return result;
     }
 
   /* Call library-specific lookup procedure.  */
   if (objfile != NULL)
-    sym = solib_global_lookup (objfile, name, domain);
+    result = solib_global_lookup (objfile, name, domain);
 
   /* If that didn't work go a global search (of global blocks, heh).  */
-  if (sym == NULL)
+  if (result.symbol == NULL)
     {
       memset (&lookup_data, 0, sizeof (lookup_data));
       lookup_data.name = name;
@@ -2743,15 +2749,15 @@ lookup_global_symbol (const char *name,
       gdbarch_iterate_over_objfiles_in_search_order
 	(objfile != NULL ? get_objfile_arch (objfile) : target_gdbarch (),
 	 lookup_symbol_global_iterator_cb, &lookup_data, objfile);
-      sym = lookup_data.result;
+      result = lookup_data.result;
     }
 
-  if (sym != NULL)
-    symbol_cache_mark_found (bsc, slot, objfile, sym);
+  if (result.symbol != NULL)
+    symbol_cache_mark_found (bsc, slot, objfile, result.symbol, result.block);
   else
     symbol_cache_mark_not_found (bsc, slot, objfile, name, domain);
 
-  return sym;
+  return result;
 }
 
 int
@@ -4602,7 +4608,7 @@ search_symbols (const char *regexp, enum search_domain kind,
 		       (MSYMBOL_VALUE_ADDRESS (objfile, msymbol)) == NULL)
 		    : (lookup_symbol_in_objfile_from_linkage_name
 		       (objfile, MSYMBOL_LINKAGE_NAME (msymbol), VAR_DOMAIN)
-		       == NULL))
+		       .symbol == NULL))
 		  found_misc = 1;
 	      }
 	  }
@@ -4705,7 +4711,7 @@ search_symbols (const char *regexp, enum search_domain kind,
 		  {
 		    if (lookup_symbol_in_objfile_from_linkage_name
 			(objfile, MSYMBOL_LINKAGE_NAME (msymbol), VAR_DOMAIN)
-			== NULL)
+			.symbol == NULL)
 		      {
 			/* match */
 			struct symbol_search *psr = (struct symbol_search *)