Spelling suggestions for misspelled preprocessor directives

This patch allows the preprocessor to offer suggestions for misspelled
directives, taking us from e.g.:

test.c:5:2: error: invalid preprocessing directive #endfi
 #endfi
  ^~~~~

to:

test.c:5:2: error: invalid preprocessing directive #endfi; did you mean #endif?
 #endfi
  ^~~~~
  endif

gcc/c-family/ChangeLog:
	* c-common.c: Include "spellcheck.h".
	(cb_get_suggestion): New function.
	* c-common.h (cb_get_suggestion): New decl.
	* c-lex.c (init_c_lex): Initialize cb->get_suggestion to
	cb_get_suggestion.

gcc/testsuite/ChangeLog:
	* gcc.dg/cpp/misspelled-directive-1.c: New testcase.
	* gcc.dg/cpp/misspelled-directive-2.c: New testcase.

libcpp/ChangeLog:
	* directives.c (directive_names): New array.
	(_cpp_handle_directive): Offer spelling suggestions for misspelled
	directives.
	* errors.c (cpp_diagnostic_at_richloc): New function.
	(cpp_error_at_richloc): New function.
	* include/cpplib.h (struct cpp_callbacks): Add field
	"get_suggestion".
	(cpp_error_at_richloc): New decl.

From-SVN: r239585

1 files changed, 8 insertions, 0 deletions

diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index 659686b..a497811 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -597,6 +597,9 @@ struct cpp_callbacks
 
   /* Callback to parse SOURCE_DATE_EPOCH from environment.  */
   time_t (*get_source_date_epoch) (cpp_reader *);
+
+  /* Callback for providing suggestions for misspelled directives.  */
+  const char *(*get_suggestion) (cpp_reader *, const char *, const char *const *);
 };
 
 #ifdef VMS
@@ -1066,6 +1069,11 @@ extern bool cpp_error_at (cpp_reader * pfile, int level,
 			  source_location src_loc, const char *msgid, ...)
   ATTRIBUTE_PRINTF_4;
 
+extern bool cpp_error_at_richloc (cpp_reader * pfile, int level,
+				  rich_location *richloc, const char *msgid,
+				  ...)
+  ATTRIBUTE_PRINTF_4;
+
 /* In lex.c */
 extern int cpp_ideq (const cpp_token *, const char *);
 extern void cpp_output_line (cpp_reader *, FILE *);