diff options
Diffstat (limited to 'gcc/c')
| -rw-r--r-- | gcc/c/c-decl.c | 30 |
1 files changed, 27 insertions, 3 deletions
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c index b3e05be..81bd2ee 100644 --- a/gcc/c/c-decl.c +++ b/gcc/c/c-decl.c @@ -3368,8 +3368,30 @@ implicit_decl_warning (location_t loc, tree id, tree olddecl) warned = warning_at (loc, OPT_Wimplicit_function_declaration, G_("implicit declaration of function %qE"), id); - if (olddecl && warned) - locate_old_decl (olddecl); + if (warned) + { + /* Whether the olddecl is an undeclared builtin function. + locate_old_decl will not generate a diagnostic for those, + so in that case we want to look elsewhere. */ + bool undeclared_builtin = (olddecl + && TREE_CODE (olddecl) == FUNCTION_DECL + && fndecl_built_in_p (olddecl) + && !C_DECL_DECLARED_BUILTIN (olddecl)); + if (undeclared_builtin) + { + const char *header = header_for_builtin_fn (olddecl); + if (header) + { + rich_location richloc (line_table, loc); + maybe_add_include_fixit (&richloc, header, true); + inform (&richloc, + "include %qs or provide a declaration of %qE", + header, id); + } + } + else if (olddecl) + locate_old_decl (olddecl); + } if (!warned) hint.suppress (); @@ -3631,7 +3653,9 @@ implicitly_declare (location_t loc, tree functionid) (TREE_TYPE (decl))); if (!comptypes (newtype, TREE_TYPE (decl))) { - bool warned = warning_at (loc, 0, "incompatible implicit " + bool warned = warning_at (loc, + OPT_Wbuiltin_declaration_mismatch, + "incompatible implicit " "declaration of built-in " "function %qD", decl); /* See if we can hint which header to include. */ |