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, 55 insertions, 50 deletions

diff --git a/gdb/c-exp.y b/gdb/c-exp.y
index 3ea544d8ef..59cecb5f3f 100644
--- a/gdb/c-exp.y
+++ b/gdb/c-exp.y
@@ -923,8 +923,8 @@ exp     :       FALSEKEYWORD
 
 block	:	BLOCKNAME
 			{
-			  if ($1.sym)
-			    $$ = SYMBOL_BLOCK_VALUE ($1.sym);
+			  if ($1.sym.symbol)
+			    $$ = SYMBOL_BLOCK_VALUE ($1.sym.symbol);
 			  else
 			    error (_("No file or function \"%s\"."),
 				   copy_name ($1.stoken));
@@ -938,7 +938,8 @@ block	:	BLOCKNAME
 block	:	block COLONCOLON name
 			{ struct symbol *tem
 			    = lookup_symbol (copy_name ($3), $1,
-					     VAR_DOMAIN, NULL);
+					     VAR_DOMAIN, NULL).symbol;
+
 			  if (!tem || SYMBOL_CLASS (tem) != LOC_BLOCK)
 			    error (_("No function \"%s\" in specified context."),
 				   copy_name ($3));
@@ -946,7 +947,7 @@ block	:	block COLONCOLON name
 	;
 
 variable:	name_not_typename ENTRY
-			{ struct symbol *sym = $1.sym;
+			{ struct symbol *sym = $1.sym.symbol;
 
 			  if (sym == NULL || !SYMBOL_IS_ARGUMENT (sym)
 			      || !symbol_read_needs_frame (sym))
@@ -961,24 +962,24 @@ variable:	name_not_typename ENTRY
 	;
 
 variable:	block COLONCOLON name
-			{ struct symbol *sym;
-			  sym = lookup_symbol (copy_name ($3), $1,
-					       VAR_DOMAIN, NULL);
-			  if (sym == 0)
+			{ struct block_symbol sym
+			    = lookup_symbol (copy_name ($3), $1,
+					     VAR_DOMAIN, NULL);
+
+			  if (sym.symbol == 0)
 			    error (_("No symbol \"%s\" in specified context."),
 				   copy_name ($3));
-			  if (symbol_read_needs_frame (sym))
+			  if (symbol_read_needs_frame (sym.symbol))
 			    {
 			      if (innermost_block == 0
-				  || contained_in (block_found,
+				  || contained_in (sym.block,
 						   innermost_block))
-				innermost_block = block_found;
+				innermost_block = sym.block;
 			    }
 
 			  write_exp_elt_opcode (pstate, OP_VAR_VALUE);
-			  /* block_found is set by lookup_symbol.  */
-			  write_exp_elt_block (pstate, block_found);
-			  write_exp_elt_sym (pstate, sym);
+			  write_exp_elt_block (pstate, sym.block);
+			  write_exp_elt_sym (pstate, sym.symbol);
 			  write_exp_elt_opcode (pstate, OP_VAR_VALUE); }
 	;
 
@@ -1035,9 +1036,9 @@ variable:	qualified_name
 			  struct symbol *sym;
 			  struct bound_minimal_symbol msymbol;
 
-			  sym =
-			    lookup_symbol (name, (const struct block *) NULL,
-					   VAR_DOMAIN, NULL);
+			  sym
+			    = lookup_symbol (name, (const struct block *) NULL,
+					     VAR_DOMAIN, NULL).symbol;
 			  if (sym)
 			    {
 			      write_exp_elt_opcode (pstate, OP_VAR_VALUE);
@@ -1058,16 +1059,16 @@ variable:	qualified_name
 	;
 
 variable:	name_not_typename
-			{ struct symbol *sym = $1.sym;
+			{ struct block_symbol sym = $1.sym;
 
-			  if (sym)
+			  if (sym.symbol)
 			    {
-			      if (symbol_read_needs_frame (sym))
+			      if (symbol_read_needs_frame (sym.symbol))
 				{
 				  if (innermost_block == 0
-				      || contained_in (block_found,
+				      || contained_in (sym.block,
 						       innermost_block))
-				    innermost_block = block_found;
+				    innermost_block = sym.block;
 				}
 
 			      write_exp_elt_opcode (pstate, OP_VAR_VALUE);
@@ -1075,7 +1076,7 @@ variable:	name_not_typename
 				 another more inner frame which happens to
 				 be in the same block.  */
 			      write_exp_elt_block (pstate, NULL);
-			      write_exp_elt_sym (pstate, sym);
+			      write_exp_elt_sym (pstate, sym.symbol);
 			      write_exp_elt_opcode (pstate, OP_VAR_VALUE);
 			    }
 			  else if ($1.is_a_field_of_this)
@@ -1084,9 +1085,9 @@ variable:	name_not_typename
 			         not inadvertently convert from a method call
 				 to data ref.  */
 			      if (innermost_block == 0
-				  || contained_in (block_found,
+				  || contained_in (sym.block,
 						   innermost_block))
-				innermost_block = block_found;
+				innermost_block = sym.block;
 			      write_exp_elt_opcode (pstate, OP_THIS);
 			      write_exp_elt_opcode (pstate, OP_THIS);
 			      write_exp_elt_opcode (pstate, STRUCTOP_PTR);
@@ -2817,7 +2818,7 @@ lex_one_token (struct parser_state *par_state, int *is_quoted_name)
 			       VAR_DOMAIN,
 			       (parse_language (par_state)->la_language
 			        == language_cplus ? &is_a_field_of_this
-				: NULL))
+				: NULL)).symbol
 		!= NULL)
 	      {
 		/* The keyword is shadowed.  */
@@ -2838,7 +2839,8 @@ lex_one_token (struct parser_state *par_state, int *is_quoted_name)
     saw_name_at_eof = 1;
 
   yylval.ssym.stoken = yylval.sval;
-  yylval.ssym.sym = NULL;
+  yylval.ssym.sym.symbol = NULL;
+  yylval.ssym.sym.block = NULL;
   yylval.ssym.is_a_field_of_this = 0;
   return NAME;
 }
@@ -2873,7 +2875,7 @@ static int
 classify_name (struct parser_state *par_state, const struct block *block,
 	       int is_quoted_name)
 {
-  struct symbol *sym;
+  struct block_symbol bsym;
   char *copy;
   struct field_of_this_result is_a_field_of_this;
 
@@ -2883,17 +2885,17 @@ classify_name (struct parser_state *par_state, const struct block *block,
      we can refer to it unconditionally below.  */
   memset (&is_a_field_of_this, 0, sizeof (is_a_field_of_this));
 
-  sym = lookup_symbol (copy, block, VAR_DOMAIN,
-		       parse_language (par_state)->la_name_of_this
-		       ? &is_a_field_of_this : NULL);
+  bsym = lookup_symbol (copy, block, VAR_DOMAIN,
+			parse_language (par_state)->la_name_of_this
+			? &is_a_field_of_this : NULL);
 
-  if (sym && SYMBOL_CLASS (sym) == LOC_BLOCK)
+  if (bsym.symbol && SYMBOL_CLASS (bsym.symbol) == LOC_BLOCK)
     {
-      yylval.ssym.sym = sym;
+      yylval.ssym.sym = bsym;
       yylval.ssym.is_a_field_of_this = is_a_field_of_this.type != NULL;
       return BLOCKNAME;
     }
-  else if (!sym)
+  else if (!bsym.symbol)
     {
       /* If we found a field of 'this', we might have erroneously
 	 found a constructor where we wanted a type name.  Handle this
@@ -2906,11 +2908,11 @@ classify_name (struct parser_state *par_state, const struct block *block,
 	{
 	  struct field_of_this_result inner_is_a_field_of_this;
 
-	  sym = lookup_symbol (copy, block, STRUCT_DOMAIN,
-			       &inner_is_a_field_of_this);
-	  if (sym != NULL)
+	  bsym = lookup_symbol (copy, block, STRUCT_DOMAIN,
+				&inner_is_a_field_of_this);
+	  if (bsym.symbol != NULL)
 	    {
-	      yylval.tsym.type = SYMBOL_TYPE (sym);
+	      yylval.tsym.type = SYMBOL_TYPE (bsym.symbol);
 	      return TYPENAME;
 	    }
 	}
@@ -2934,18 +2936,20 @@ classify_name (struct parser_state *par_state, const struct block *block,
 	}
     }
 
-  if (sym && SYMBOL_CLASS (sym) == LOC_TYPEDEF)
+  if (bsym.symbol && SYMBOL_CLASS (bsym.symbol) == LOC_TYPEDEF)
     {
-      yylval.tsym.type = SYMBOL_TYPE (sym);
+      yylval.tsym.type = SYMBOL_TYPE (bsym.symbol);
       return TYPENAME;
     }
 
   /* See if it's an ObjC classname.  */
-  if (parse_language (par_state)->la_language == language_objc && !sym)
+  if (parse_language (par_state)->la_language == language_objc && !bsym.symbol)
     {
       CORE_ADDR Class = lookup_objc_class (parse_gdbarch (par_state), copy);
       if (Class)
 	{
+	  struct symbol *sym;
+
 	  yylval.theclass.theclass = Class;
 	  sym = lookup_struct_typedef (copy, expression_context_block, 1);
 	  if (sym)
@@ -2957,26 +2961,27 @@ classify_name (struct parser_state *par_state, const struct block *block,
   /* Input names that aren't symbols but ARE valid hex numbers, when
      the input radix permits them, can be names or numbers depending
      on the parse.  Note we support radixes > 16 here.  */
-  if (!sym
+  if (!bsym.symbol
       && ((copy[0] >= 'a' && copy[0] < 'a' + input_radix - 10)
 	  || (copy[0] >= 'A' && copy[0] < 'A' + input_radix - 10)))
     {
       YYSTYPE newlval;	/* Its value is ignored.  */
       int hextype = parse_number (par_state, copy, yylval.sval.length,
 				  0, &newlval);
+
       if (hextype == INT)
 	{
-	  yylval.ssym.sym = sym;
+	  yylval.ssym.sym = bsym;
 	  yylval.ssym.is_a_field_of_this = is_a_field_of_this.type != NULL;
 	  return NAME_OR_INT;
 	}
     }
 
   /* Any other kind of symbol */
-  yylval.ssym.sym = sym;
+  yylval.ssym.sym = bsym;
   yylval.ssym.is_a_field_of_this = is_a_field_of_this.type != NULL;
 
-  if (sym == NULL
+  if (bsym.symbol == NULL
       && parse_language (par_state)->la_language == language_cplus
       && is_a_field_of_this.type == NULL
       && lookup_minimal_symbol (copy, NULL, NULL).minsym == NULL)
@@ -3010,7 +3015,7 @@ classify_inner_name (struct parser_state *par_state,
   /* If no symbol was found, search for a matching base class named
      COPY.  This will allow users to enter qualified names of class members
      relative to the `this' pointer.  */
-  if (yylval.ssym.sym == NULL)
+  if (yylval.ssym.sym.symbol == NULL)
     {
       struct type *base_type = cp_find_type_baseclass_by_name (type, copy);
 
@@ -3023,7 +3028,7 @@ classify_inner_name (struct parser_state *par_state,
       return ERROR;
     }
 
-  switch (SYMBOL_CLASS (yylval.ssym.sym))
+  switch (SYMBOL_CLASS (yylval.ssym.sym.symbol))
     {
     case LOC_BLOCK:
     case LOC_LABEL:
@@ -3042,7 +3047,7 @@ classify_inner_name (struct parser_state *par_state,
       return ERROR;
 
     case LOC_TYPEDEF:
-      yylval.tsym.type = SYMBOL_TYPE (yylval.ssym.sym);
+      yylval.tsym.type = SYMBOL_TYPE (yylval.ssym.sym.symbol);
       return TYPENAME;
 
     default:
@@ -3302,8 +3307,8 @@ c_print_token (FILE *file, int type, YYSTYPE value)
     case BLOCKNAME:
       fprintf (file, "ssym<name=%s, sym=%s, field_of_this=%d>",
 	       copy_name (value.ssym.stoken),
-	       (value.ssym.sym == NULL
-		? "(null)" : SYMBOL_PRINT_NAME (value.ssym.sym)),
+	       (value.ssym.sym.symbol == NULL
+		? "(null)" : SYMBOL_PRINT_NAME (value.ssym.sym.symbol)),
 	       value.ssym.is_a_field_of_this);
       break;