c.opt (fextended-identifiers): New.

gcc:
	* c.opt (fextended-identifiers): New.
	* c-opts.c (c_common_handle_option): Handle
	-fextended-identifiers.
	* doc/cpp.texi: Update documentation of extended identifiers.
	* doc/cppopts.texi (-fextended-identifiers): Document.

gcc/testsuite:
	* g++.dg/cpp/ucnid-1.C, g++.dg/cpp/normalize-1.C,
	g++.dg/other/ucnid-1.C, gcc.dg/cpp/normalize-1.c,
	gcc.dg/cpp/normalize-2.c, gcc.dg/cpp/normalize-3.c,
	gcc.dg/cpp/normalize-4.c, gcc.dg/cpp/ucnid-1.c,
	gcc.dg/cpp/ucnid-2.c, gcc.dg/cpp/ucnid-3.c, gcc.dg/cpp/ucnid-4.c,
	gcc.dg/cpp/ucnid-5.c, gcc.dg/cpp/ucnid-7.c,gcc.dg/ucnid-1.c,
	gcc.dg/ucnid-2.c, gcc.dg/ucnid-3.c, gcc.dg/ucnid-4.c,
	gcc.dg/ucnid-5.c, gcc.dg/ucnid-6.c: Add -fextended-identifiers.
	* gcc.dg/cpp/ucnid-8.c: New test.

libcpp:
	* include/cpplib.h (struct cpp_options): Add extended_identifiers.
	* init.c (struct lang_flags, lang_defaults): Add
	extended_identifiers.
	(cpp_set_lang): Use it.
	* lex.c (forms_identifier_p): Check extended_identifiers.

From-SVN: r104462

2 files changed, 17 insertions, 7 deletions

diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi
index f5f29a6..c019adb 100644
--- a/gcc/doc/cpp.texi
+++ b/gcc/doc/cpp.texi
@@ -281,11 +281,11 @@ the character in the source character set that they represent, then
 converted to the execution character set, just like unescaped
 characters.
 
+Unless the experimental @option{-fextended-identifiers} option is used,
 GCC does not permit the use of characters outside the ASCII range, nor
-@samp{\u} and @samp{\U} escapes, in identifiers.  We hope this will
-change eventually, but there are problems with the standard semantics
-of such ``extended identifiers'' which must be resolved through the
-ISO C and C++ committees first.
+@samp{\u} and @samp{\U} escapes, in identifiers.  Even with that
+option, characters outside the ASCII range can only be specified with
+the @samp{\u} and @samp{\U} escapes, not used directly in identifiers.
 
 @node Initial processing
 @section Initial processing
@@ -510,8 +510,10 @@ In the 1999 C standard, identifiers may contain letters which are not
 part of the ``basic source character set'', at the implementation's
 discretion (such as accented Latin letters, Greek letters, or Chinese
 ideograms).  This may be done with an extended character set, or the
-@samp{\u} and @samp{\U} escape sequences.  GCC does not presently
-implement either feature in the preprocessor or the compiler.
+@samp{\u} and @samp{\U} escape sequences.  The implementation of this
+feature in GCC is experimental; such characters are only accepted in
+the @samp{\u} and @samp{\U} forms and only if
+@option{-fextended-identifiers} is used.
 
 As an extension, GCC treats @samp{$} as a letter.  This is for
 compatibility with some systems, such as VMS, where @samp{$} is commonly
@@ -3791,7 +3793,9 @@ character set may be controlled by the user, with the
 The C and C++ standards allow identifiers to be composed of @samp{_}
 and the alphanumeric characters.  C++ and C99 also allow universal
 character names, and C99 further permits implementation-defined
-characters.
+characters.  GCC currently only permits universal character names if
+@option{-fextended-identifiers} is used, because the implementation of
+universal character names in identifiers is experimental.
 
 GCC allows the @samp{$} character in identifiers as an extension for
 most targets.  This is true regardless of the @option{std=} switch,
diff --git a/gcc/doc/cppopts.texi b/gcc/doc/cppopts.texi
index 2790e8c..adf77e1 100644
--- a/gcc/doc/cppopts.texi
+++ b/gcc/doc/cppopts.texi
@@ -511,6 +511,12 @@ Accept @samp{$} in identifiers.
   @xref{Identifier characters}.
 @end ifset
 
+@item -fextended-identifiers
+@opindex fextended-identifiers
+Accept universal character names in identifiers.  This option is
+experimental; in a future version of GCC, it will be enabled by
+default for C99 and C++.
+
 @item -fpreprocessed
 @opindex fpreprocessed
 Indicate to the preprocessor that the input file has already been