| Message ID | 2508992.5cBtdV5qiJ@arcturus.home |
|---|---|
| State | New |
| Headers | show |
| Series | Fix crash with -fdump-ada-spec | expand |
On Wed, 21 Aug 2019, Eric Botcazou wrote: > This fixes a crash of the C compiler when -fdump-ada-spec is passed for: > > extern void (*signal (int __sig, void (*__handler)(int)))(int); > > It appears that the C parser is somewhat confused by this declaration and > builds a FUNCTION_DECL whose type has got 2 arguments (TYPE_ARG_TYPES list) > but which itself has got only 1 argument (DECL_ARGUMENTS list) corresponding > to the anonymous (int) at the end. The C++ parser doesn't have the issue. > > Joseph, is that a known issue of the C parser? The problem is that the logic in c_parser_declaration_or_fndef for setting DECL_ARGUMENTS (not previously meaningful in non-definition declarations at all), as introduced by r253411 | dmalcolm | 2017-10-04 14:10:59 +0000 (Wed, 04 Oct 2017) | 85 lines C: underline parameters in mismatching function calls (and subsequently changed by r268574, but that change isn't relevant here) is incorrect. Rather than checking if the outermost declarator is cdk_function and using its parameters if so, it's necessary to check if the *innermost declarator that isn't cdk_id or cdk_attrs* is cdk_function and use its parameters if so, as that's what actually determines if the declarator for the entity being declared has the form of a function declarator (see how grokdeclarator determines funcdef_syntax). In your example, the outermost declarator is the one for the target type of the pointer that is the return type.
> The problem is that the logic in c_parser_declaration_or_fndef for setting > DECL_ARGUMENTS (not previously meaningful in non-definition declarations > at all), as introduced by > > r253411 | dmalcolm | 2017-10-04 14:10:59 +0000 (Wed, 04 Oct 2017) | 85 lines > > C: underline parameters in mismatching function calls > > (and subsequently changed by r268574, but that change isn't relevant here) > is incorrect. As a matter of fact, this logic helped -fdump-ada-spec too by making the name of the parameters available in non-definition declarations. > Rather than checking if the outermost declarator is > cdk_function and using its parameters if so, it's necessary to check if > the *innermost declarator that isn't cdk_id or cdk_attrs* is cdk_function > and use its parameters if so, as that's what actually determines if the > declarator for the entity being declared has the form of a function > declarator (see how grokdeclarator determines funcdef_syntax). Thanks for the hint. Tentative patch attached based on it, which certainly makes -fdump-ada-spec happy, as witnessed by the dump-ada-spec-15.c change. Is it something that you would approve for mainline? c/ * c-parser.c (c_parser_declaration_or_fndef): Set DECL_ARGUMENTS of a FUNCTION_DECL to the right value in the presence of nested declarators. testsuite/ * c-c++-common/dump-ada-spec-15.c: Check that the parameters are named.
On Wed, 21 Aug 2019, Eric Botcazou wrote: > > Rather than checking if the outermost declarator is > > cdk_function and using its parameters if so, it's necessary to check if > > the *innermost declarator that isn't cdk_id or cdk_attrs* is cdk_function > > and use its parameters if so, as that's what actually determines if the > > declarator for the entity being declared has the form of a function > > declarator (see how grokdeclarator determines funcdef_syntax). > > Thanks for the hint. Tentative patch attached based on it, which certainly > makes -fdump-ada-spec happy, as witnessed by the dump-ada-spec-15.c change. > > Is it something that you would approve for mainline? This patch is OK.
Index: c-family/c-ada-spec.c =================================================================== --- c-family/c-ada-spec.c (revision 274744) +++ c-family/c-ada-spec.c (working copy) @@ -1589,14 +1589,13 @@ dump_ada_function_declaration (pretty_printer *buf bool is_method, bool is_constructor, bool is_destructor, int spc) { - tree arg; - const tree node = TREE_TYPE (func); + tree type = TREE_TYPE (func); + tree arg = TYPE_ARG_TYPES (type); + tree t; char buf[17]; - int num = 0, num_args = 0, have_args = true, have_ellipsis = false; + int num, num_args = 0, have_args = true, have_ellipsis = false; /* Compute number of arguments. */ - arg = TYPE_ARG_TYPES (node); - if (arg) { while (TREE_CHAIN (arg) && arg != error_mark_node) @@ -1627,25 +1626,29 @@ dump_ada_function_declaration (pretty_printer *buf pp_left_paren (buffer); } + /* For a function, see if we have the corresponding arguments. */ if (TREE_CODE (func) == FUNCTION_DECL) - arg = DECL_ARGUMENTS (func); + { + arg = DECL_ARGUMENTS (func); + for (t = arg, num = 0; t; t = DECL_CHAIN (t)) + num++; + if (num < num_args) + arg = NULL_TREE; + } else arg = NULL_TREE; - if (arg == NULL_TREE) + /* Otherwise, only print the types. */ + if (!arg) { have_args = false; - arg = TYPE_ARG_TYPES (node); - - if (arg && TREE_CODE (TREE_VALUE (arg)) == VOID_TYPE) - arg = NULL_TREE; + arg = TYPE_ARG_TYPES (type); } if (is_constructor) arg = TREE_CHAIN (arg); - /* Print the argument names (if available) & types. */ - + /* Print the argument names (if available) and types. */ for (num = 1; num <= num_args; num++) { if (have_args) @@ -1663,13 +1666,13 @@ dump_ada_function_declaration (pretty_printer *buf pp_string (buffer, buf); } - dump_ada_node (buffer, TREE_TYPE (arg), node, spc, false, true); + dump_ada_node (buffer, TREE_TYPE (arg), type, spc, false, true); } else { sprintf (buf, "arg%d : ", num); pp_string (buffer, buf); - dump_ada_node (buffer, TREE_VALUE (arg), node, spc, false, true); + dump_ada_node (buffer, TREE_VALUE (arg), type, spc, false, true); } /* If the type is a pointer to a tagged type, we need to differentiate @@ -1707,11 +1710,11 @@ dump_ada_function_declaration (pretty_printer *buf if (num_args > 0) pp_right_paren (buffer); - if (is_constructor || !VOID_TYPE_P (TREE_TYPE (node))) + if (is_constructor || !VOID_TYPE_P (TREE_TYPE (type))) { pp_string (buffer, " return "); - tree type = is_constructor ? DECL_CONTEXT (func) : TREE_TYPE (node); - dump_ada_node (buffer, type, type, spc, false, true); + tree rtype = is_constructor ? DECL_CONTEXT (func) : TREE_TYPE (type); + dump_ada_node (buffer, rtype, rtype, spc, false, true); } }