[PATCH] c++: Fix missing NSDMI diagnostic in C++98 [PR103347]

Marek Polacek polacek@redhat.com
Mon Nov 22 22:17:34 GMT 2021


Here the problem is that we aren't detecting a NSDMI in C++98:

struct A {
  void *x = NULL;
};

because maybe_warn_cpp0x uses input_location and that happens to point
to NULL which comes from a system header.  Jakub suggested changing the
location to the '=', thereby avoiding the system header problem.  To
that end, I've added a new location_t member into cp_declarator.  This
member is used when this declarator is part of an init-declarator.  The
rest of the changes is obvious.  I've also taken the liberty of adding
loc_or_input_loc, since I want to avoid checking for UNKNOWN_LOCATION.

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

	PR c++/103347

gcc/cp/ChangeLog:

	* cp-tree.h (struct cp_declarator): Add a location_t member.
	(maybe_warn_cpp0x): Add a location_t parameter with a default argument.
	(loc_or_input_loc): New.
	* decl.c (grokdeclarator): Use loc_or_input_loc.  Pass init_loc down
	to maybe_warn_cpp0x.
	* error.c (maybe_warn_cpp0x): Add a location_t parameter.  Use it.
	* parser.c (make_declarator): Initialize init_loc.
	(cp_parser_member_declaration): Set init_loc.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/nsdmi-warn1.C: New test.
	* g++.dg/cpp0x/nsdmi-warn1.h: New file.
---
 gcc/cp/cp-tree.h                         | 16 +++++++++---
 gcc/cp/decl.c                            | 22 +++++++++-------
 gcc/cp/error.c                           | 32 ++++++++++++------------
 gcc/cp/parser.c                          |  2 ++
 gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.C | 10 ++++++++
 gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.h |  2 ++
 6 files changed, 55 insertions(+), 29 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.C
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.h

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 3f56cb90d14..2037082b0c7 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6231,9 +6231,11 @@ struct cp_declarator {
   /* If this declarator is parenthesized, this the open-paren.  It is
      UNKNOWN_LOCATION when not parenthesized.  */
   location_t parenthesized;
-
-  location_t id_loc; /* Currently only set for cdk_id, cdk_decomp and
-			cdk_function. */
+  /* Currently only set for cdk_id, cdk_decomp and cdk_function.  */
+  location_t id_loc;
+  /* If this declarator is part of an init-declarator, the location of the
+     initializer.  */
+  location_t init_loc;
   /* GNU Attributes that apply to this declarator.  If the declarator
      is a pointer or a reference, these attribute apply to the type
      pointed to.  */
@@ -6878,7 +6880,8 @@ extern const char *lang_decl_dwarf_name		(tree, int, bool);
 extern const char *language_to_string		(enum languages);
 extern const char *class_key_or_enum_as_string	(tree);
 extern void maybe_warn_variadic_templates       (void);
-extern void maybe_warn_cpp0x			(cpp0x_warn_str str);
+extern void maybe_warn_cpp0x			(cpp0x_warn_str str,
+						 location_t = input_location);
 extern bool pedwarn_cxx98                       (location_t, int, const char *, ...) ATTRIBUTE_GCC_DIAG(3,4);
 extern location_t location_of                   (tree);
 extern void qualified_name_lookup_error		(tree, tree, tree,
@@ -7996,6 +7999,11 @@ extern bool decl_in_std_namespace_p	     (tree);
 extern void require_complete_eh_spec_types	(tree, tree);
 extern void cxx_incomplete_type_diagnostic	(location_t, const_tree,
 						 const_tree, diagnostic_t);
+inline location_t
+loc_or_input_loc (location_t loc)
+{
+  return loc == UNKNOWN_LOCATION ? input_location : loc;
+}
 
 inline location_t
 cp_expr_loc_or_loc (const_tree t, location_t or_loc)
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 9f68d1a5590..ae0e0bae9cc 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -11522,14 +11522,18 @@ grokdeclarator (const cp_declarator *declarator,
   if (initialized == SD_DEFAULTED || initialized == SD_DELETED)
     funcdef_flag = true;
 
-  location_t typespec_loc = smallest_type_location (type_quals,
-						    declspecs->locations);
-  if (typespec_loc == UNKNOWN_LOCATION)
-    typespec_loc = input_location;
-
-  location_t id_loc = declarator ? declarator->id_loc : input_location;
-  if (id_loc == UNKNOWN_LOCATION)
-    id_loc = input_location;
+  location_t typespec_loc = loc_or_input_loc (smallest_type_location
+					      (type_quals,
+					       declspecs->locations));
+  location_t id_loc;
+  location_t init_loc;
+  if (declarator)
+    {
+      id_loc = loc_or_input_loc (declarator->id_loc);
+      init_loc = loc_or_input_loc (declarator->init_loc);
+    }
+  else
+    init_loc = id_loc = input_location;
 
   /* Look inside a declarator for the name being declared
      and get it as a string, for an error message.  */
@@ -14042,7 +14046,7 @@ grokdeclarator (const cp_declarator *declarator,
 		  {
 		    /* An attempt is being made to initialize a non-static
 		       member.  This is new in C++11.  */
-		    maybe_warn_cpp0x (CPP0X_NSDMI);
+		    maybe_warn_cpp0x (CPP0X_NSDMI, init_loc);
 
 		    /* If this has been parsed with static storage class, but
 		       errors forced staticp to be cleared, ensure NSDMI is
diff --git a/gcc/cp/error.c b/gcc/cp/error.c
index 872479369ab..98c1f0e4bdf 100644
--- a/gcc/cp/error.c
+++ b/gcc/cp/error.c
@@ -4428,84 +4428,84 @@ cp_printer (pretty_printer *pp, text_info *text, const char *spec,
 
 /* Warn about the use of C++0x features when appropriate.  */
 void
-maybe_warn_cpp0x (cpp0x_warn_str str)
+maybe_warn_cpp0x (cpp0x_warn_str str, location_t loc/*=input_location*/)
 {
   if (cxx_dialect == cxx98)
     switch (str)
       {
       case CPP0X_INITIALIZER_LISTS:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "extended initializer lists "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_EXPLICIT_CONVERSION:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "explicit conversion operators "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_VARIADIC_TEMPLATES:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "variadic templates "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_LAMBDA_EXPR:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "lambda expressions "
 		  "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_AUTO:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "C++11 auto only available with %<-std=c++11%> or "
 		 "%<-std=gnu++11%>");
 	break;
       case CPP0X_SCOPED_ENUMS:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "scoped enums only available with %<-std=c++11%> or "
 		 "%<-std=gnu++11%>");
 	break;
       case CPP0X_DEFAULTED_DELETED:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "defaulted and deleted functions "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_INLINE_NAMESPACES:
 	if (pedantic)
-	  pedwarn (input_location, OPT_Wc__11_extensions,
+	  pedwarn (loc, OPT_Wc__11_extensions,
 		   "inline namespaces "
 		   "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_OVERRIDE_CONTROLS:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "override controls (override/final) "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
         break;
       case CPP0X_NSDMI:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "non-static data member initializers "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
         break;
       case CPP0X_USER_DEFINED_LITERALS:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "user-defined literals "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_DELEGATING_CTORS:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "delegating constructors "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
         break;
       case CPP0X_INHERITING_CTORS:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "inheriting constructors "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
         break;
       case CPP0X_ATTRIBUTES:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "C++11 attributes "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
       case CPP0X_REF_QUALIFIER:
-	pedwarn (input_location, OPT_Wc__11_extensions,
+	pedwarn (loc, OPT_Wc__11_extensions,
 		 "ref-qualifiers "
 		 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
 	break;
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index e2b5d6842fc..162aff73f91 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -1542,6 +1542,7 @@ make_declarator (cp_declarator_kind kind)
   declarator->declarator = NULL;
   declarator->parameter_pack_p = false;
   declarator->id_loc = UNKNOWN_LOCATION;
+  declarator->init_loc = UNKNOWN_LOCATION;
 
   return declarator;
 }
@@ -27143,6 +27144,7 @@ cp_parser_member_declaration (cp_parser* parser)
 		     constant-initializer.  When we call `grokfield', it will
 		     perform more stringent semantics checks.  */
 		  initializer_token_start = cp_lexer_peek_token (parser->lexer);
+		  declarator->init_loc = initializer_token_start->location;
 		  if (function_declarator_p (declarator)
 		      || (decl_specifiers.type
 			  && TREE_CODE (decl_specifiers.type) == TYPE_DECL
diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.C
new file mode 100644
index 00000000000..aacc8b28255
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.C
@@ -0,0 +1,10 @@
+// PR c++/103347
+// { dg-do compile { target c++11_down } }
+
+#include "nsdmi-warn1.h"
+
+struct A {
+  void *x = NULL; // { dg-error "11:only available" "" { target c++98_only } }
+  void *y{NULL}; // { dg-error "only available|extended initializer" "" { target c++98_only } }
+  int z = 1 + 2; // { dg-error "9:only available" "" { target c++98_only } }
+};
diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.h b/gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.h
new file mode 100644
index 00000000000..ee5be5a2478
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-warn1.h
@@ -0,0 +1,2 @@
+#pragma GCC system_header
+#define NULL (void *)0

base-commit: a944b5dec3adb28ed199234d2116145ca9010d6a
-- 
2.33.1



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