c-family: add name_hint/deferred_diagnostic

In various places we use lookup_name_fuzzy to provide a hint,
and can report messages of the form:
  error: unknown foo named 'bar'
or:
  error: unknown foo named 'bar'; did you mean 'SUGGESTION?

This patch provides a way for lookup_name_fuzzy to provide
both the suggestion above, and (optionally) additional hints
that can be printed e.g.

  note: did you forget to include <SOME_HEADER.h>?

This patch provides the mechanism and ports existing users
of lookup_name_fuzzy to the new return type.
There are no uses of such hints in this patch, but followup
patches provide various front-end specific uses of this.

gcc/c-family/ChangeLog:
	* c-common.h (enum lookup_name_fuzzy_kind): Move to name-hint.h.
	(lookup_name_fuzzy): Likewise.  Convert return type from
	const char * to name_hint.  Add location_t param.
	* name-hint.h: New header.

gcc/c/ChangeLog:
	* c-decl.c: Define INCLUDE_UNIQUE_PTR before including system.h.
	Include "c-family/name-hint.h"
	(implicit_decl_warning): Convert "hint" from
	const char * to name_hint.  Pass location to
	lookup_name_fuzzy.  Suppress any deferred diagnostic if the
	warning was not printed.
	(undeclared_variable): Likewise for "guessed_id".
	(lookup_name_fuzzy): Convert return type from const char *
	to name_hint.  Add location_t param.
	* c-parser.c: Define INCLUDE_UNIQUE_PTR before including system.h.
	Include "c-family/name-hint.h"
	(c_parser_declaration_or_fndef): Convert "hint" from
	const char * to name_hint.  Pass location to lookup_name_fuzzy.
	(c_parser_parameter_declaration): Likewise.

gcc/cp/ChangeLog:
	* name-lookup.c: Define INCLUDE_UNIQUE_PTR before including system.h.
	Include "c-family/name-hint.h"
	(suggest_alternatives_for): Convert "fuzzy_name" from const char *
	to name_hint, and rename to "hint".  Pass location to
	lookup_name_fuzzy.
	(lookup_name_fuzzy): Convert return type from const char *
	to name_hint.  Add location_t param.
	* parser.c: Define INCLUDE_UNIQUE_PTR before including system.h.
	Include "c-family/name-hint.h"
	(cp_parser_diagnose_invalid_type_name): Convert
	"suggestion" from const char * to name_hint, and rename to "hint".
	Pass location to lookup_name_fuzzy.

From-SVN: r254963

3 files changed, 49 insertions, 23 deletions

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index b10ebfc..6e19393 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,20 @@
+2017-11-20  David Malcolm  <dmalcolm@redhat.com>
+
+	* c-decl.c: Define INCLUDE_UNIQUE_PTR before including system.h.
+	Include "c-family/name-hint.h"
+	(implicit_decl_warning): Convert "hint" from
+	const char * to name_hint.  Pass location to
+	lookup_name_fuzzy.  Suppress any deferred diagnostic if the
+	warning was not printed.
+	(undeclared_variable): Likewise for "guessed_id".
+	(lookup_name_fuzzy): Convert return type from const char *
+	to name_hint.  Add location_t param.
+	* c-parser.c: Define INCLUDE_UNIQUE_PTR before including system.h.
+	Include "c-family/name-hint.h"
+	(c_parser_declaration_or_fndef): Convert "hint" from
+	const char * to name_hint.  Pass location to lookup_name_fuzzy.
+	(c_parser_parameter_declaration): Likewise.
+
 2017-11-19  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/66618
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index d95a2b6..7726476 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -25,6 +25,7 @@ along with GCC; see the file COPYING3.  If not see
    line numbers.  For example, the CONST_DECLs for enum values.  */
 
 #include "config.h"
+#define INCLUDE_UNIQUE_PTR
 #include "system.h"
 #include "coretypes.h"
 #include "target.h"
@@ -54,6 +55,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "spellcheck-tree.h"
 #include "gcc-rich-location.h"
 #include "asan.h"
+#include "c-family/name-hint.h"
 
 /* In grokdeclarator, distinguish syntactic contexts of declarators.  */
 enum decl_context
@@ -3109,20 +3111,20 @@ implicit_decl_warning (location_t loc, tree id, tree olddecl)
     return;
 
   bool warned;
-  const char *hint = NULL;
+  name_hint hint;
   if (!olddecl)
-    hint = lookup_name_fuzzy (id, FUZZY_LOOKUP_FUNCTION_NAME);
+    hint = lookup_name_fuzzy (id, FUZZY_LOOKUP_FUNCTION_NAME, loc);
 
   if (flag_isoc99)
     {
       if (hint)
 	{
 	  gcc_rich_location richloc (loc);
-	  richloc.add_fixit_replace (hint);
+	  richloc.add_fixit_replace (hint.suggestion ());
 	  warned = pedwarn (&richloc, OPT_Wimplicit_function_declaration,
 			    "implicit declaration of function %qE;"
 			    " did you mean %qs?",
-			    id, hint);
+			    id, hint.suggestion ());
 	}
       else
 	warned = pedwarn (loc, OPT_Wimplicit_function_declaration,
@@ -3131,11 +3133,11 @@ implicit_decl_warning (location_t loc, tree id, tree olddecl)
   else if (hint)
     {
       gcc_rich_location richloc (loc);
-      richloc.add_fixit_replace (hint);
+      richloc.add_fixit_replace (hint.suggestion ());
       warned = warning_at
 	(&richloc, OPT_Wimplicit_function_declaration,
 	 G_("implicit declaration of function %qE; did you mean %qs?"),
-	 id, hint);
+	 id, hint.suggestion ());
     }
   else
     warned = warning_at (loc, OPT_Wimplicit_function_declaration,
@@ -3143,6 +3145,9 @@ implicit_decl_warning (location_t loc, tree id, tree olddecl)
 
   if (olddecl && warned)
     locate_old_decl (olddecl);
+
+  if (!warned)
+    hint.suppress ();
 }
 
 /* This function represents mapping of a function code FCODE
@@ -3466,15 +3471,15 @@ undeclared_variable (location_t loc, tree id)
 
   if (current_function_decl == NULL_TREE)
     {
-      const char *guessed_id = lookup_name_fuzzy (id, FUZZY_LOOKUP_NAME);
+      name_hint guessed_id = lookup_name_fuzzy (id, FUZZY_LOOKUP_NAME, loc);
       if (guessed_id)
 	{
 	  gcc_rich_location richloc (loc);
-	  richloc.add_fixit_replace (guessed_id);
+	  richloc.add_fixit_replace (guessed_id.suggestion ());
 	  error_at (&richloc,
 		    "%qE undeclared here (not in a function);"
 		    " did you mean %qs?",
-		    id, guessed_id);
+		    id, guessed_id.suggestion ());
 	}
       else
 	error_at (loc, "%qE undeclared here (not in a function)", id);
@@ -3484,15 +3489,15 @@ undeclared_variable (location_t loc, tree id)
     {
       if (!objc_diagnose_private_ivar (id))
 	{
-	  const char *guessed_id = lookup_name_fuzzy (id, FUZZY_LOOKUP_NAME);
+	  name_hint guessed_id = lookup_name_fuzzy (id, FUZZY_LOOKUP_NAME, loc);
 	  if (guessed_id)
 	    {
 	      gcc_rich_location richloc (loc);
-	      richloc.add_fixit_replace (guessed_id);
+	      richloc.add_fixit_replace (guessed_id.suggestion ());
 	      error_at (&richloc,
 			"%qE undeclared (first use in this function);"
 			" did you mean %qs?",
-			id, guessed_id);
+			id, guessed_id.suggestion ());
 	    }
 	  else
 	    error_at (loc, "%qE undeclared (first use in this function)", id);
@@ -4003,8 +4008,8 @@ lookup_name_in_scope (tree name, struct c_scope *scope)
    It also looks for start_typename keywords, to detect "singed" vs "signed"
    typos.  */
 
-const char *
-lookup_name_fuzzy (tree name, enum lookup_name_fuzzy_kind kind)
+name_hint
+lookup_name_fuzzy (tree name, enum lookup_name_fuzzy_kind kind, location_t)
 {
   gcc_assert (TREE_CODE (name) == IDENTIFIER_NODE);
 
@@ -4094,9 +4099,9 @@ lookup_name_fuzzy (tree name, enum lookup_name_fuzzy_kind kind)
 
   tree best = bm.get_best_meaningful_candidate ();
   if (best)
-    return IDENTIFIER_POINTER (best);
+    return name_hint (IDENTIFIER_POINTER (best), NULL);
   else
-    return NULL;
+    return name_hint (NULL, NULL);
 }
 
 
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index bd5dd57..4afa9ce 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3.  If not see
    location rather than implicitly using input_location.  */
 
 #include "config.h"
+#define INCLUDE_UNIQUE_PTR
 #include "system.h"
 #include "coretypes.h"
 #include "target.h"
@@ -65,6 +66,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "read-rtl-function.h"
 #include "run-rtl-passes.h"
 #include "intl.h"
+#include "c-family/name-hint.h"
 
 /* We need to walk over decls with incomplete struct/union/enum types
    after parsing the whole translation unit.
@@ -1808,13 +1810,14 @@ c_parser_declaration_or_fndef (c_parser *parser, bool fndef_ok,
 	}
       else
 	{
-	  const char *hint = lookup_name_fuzzy (name, FUZZY_LOOKUP_TYPENAME);
+	  name_hint hint = lookup_name_fuzzy (name, FUZZY_LOOKUP_TYPENAME,
+					      here);
 	  if (hint)
 	    {
-	      richloc.add_fixit_replace (hint);
+	      richloc.add_fixit_replace (hint.suggestion ());
 	      error_at (&richloc,
 			"unknown type name %qE; did you mean %qs?",
-			name, hint);
+			name, hint.suggestion ());
 	    }
 	  else
 	    error_at (here, "unknown type name %qE", name);
@@ -4066,15 +4069,16 @@ c_parser_parameter_declaration (c_parser *parser, tree attrs)
       c_parser_set_source_position_from_token (token);
       if (c_parser_next_tokens_start_typename (parser, cla_prefer_type))
 	{
-	  const char *hint = lookup_name_fuzzy (token->value,
-						FUZZY_LOOKUP_TYPENAME);
+	  name_hint hint = lookup_name_fuzzy (token->value,
+					      FUZZY_LOOKUP_TYPENAME,
+					      token->location);
 	  if (hint)
 	    {
 	      gcc_rich_location richloc (token->location);
-	      richloc.add_fixit_replace (hint);
+	      richloc.add_fixit_replace (hint.suggestion ());
 	      error_at (&richloc,
 			"unknown type name %qE; did you mean %qs?",
-			token->value, hint);
+			token->value, hint.suggestion ());
 	    }
 	  else
 	    error_at (token->location, "unknown type name %qE", token->value);