c++: Implement C++23 P0330 - Literal Suffixes for ptrdiff_t and size_t.

Integer literal suffixes for signed size ('z') and unsigned size
(some permutation od 'zu') are provided as a language addition.

gcc/c-family/ChangeLog:

	* c-cppbuiltin.c (c_cpp_builtins): Define __cpp_size_t_suffix.
	* c-lex.c (interpret_integer): Set node type for size literal.

libcpp/ChangeLog:

	* expr.c (interpret_int_suffix): Detect 'z' integer suffix.
	(cpp_classify_number): Compat warning for use of 'z' suffix.
	* include/cpplib.h (struct cpp_options): New flag.
	(enum cpp_warning_reason): New flag.
	(CPP_N_USERDEF): Comment C++0x -> C++11.
	(CPP_N_SIZE_T): New flag for cpp_classify_number.
	* init.c (cpp_set_lang): Initialize new flag.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/udlit-shadow-neg.C: Test for 'z' and 'zu' shadowing.
	* g++.dg/cpp23/feat-cxx2b.C: New test.
	* g++.dg/cpp23/size_t-literals.C: New test.
	* g++.dg/warn/Wsize_t-literals.C: New test.

3 files changed, 58 insertions, 30 deletions

diff --git a/libcpp/expr.c b/libcpp/expr.c
index 474ea4d..42007f9 100644
--- a/libcpp/expr.c
+++ b/libcpp/expr.c
@@ -313,13 +313,14 @@ static unsigned int
 interpret_int_suffix (cpp_reader *pfile, const uchar *s, size_t len)
 {
   size_t orig_len = len;
-  size_t u, l, i;
+  size_t u, l, i, z;
 
-  u = l = i = 0;
+  u = l = i = z = 0;
 
   while (len--)
     switch (s[len])
       {
+      case 'z': case 'Z':	z++; break;
       case 'u': case 'U':	u++; break;
       case 'i': case 'I':
       case 'j': case 'J':	i++; break;
@@ -332,9 +333,17 @@ interpret_int_suffix (cpp_reader *pfile, const uchar *s, size_t len)
 	return 0;
       }
 
-  if (l > 2 || u > 1 || i > 1)
+  if (l > 2 || u > 1 || i > 1 || z > 1)
     return 0;
 
+  if (z)
+    {
+      if (l > 0 || i > 0)
+	return 0;
+      if (!CPP_OPTION (pfile, cplusplus))
+	return 0;
+    }
+
   if (i)
     {
       if (!CPP_OPTION (pfile, ext_numeric_literals))
@@ -352,7 +361,8 @@ interpret_int_suffix (cpp_reader *pfile, const uchar *s, size_t len)
   return ((i ? CPP_N_IMAGINARY : 0)
 	  | (u ? CPP_N_UNSIGNED : 0)
 	  | ((l == 0) ? CPP_N_SMALL
-	     : (l == 1) ? CPP_N_MEDIUM : CPP_N_LARGE));
+	     : (l == 1) ? CPP_N_MEDIUM : CPP_N_LARGE)
+	  | (z ? CPP_N_SIZE_T : 0));
 }
 
 /* Return the classification flags for an int suffix.  */
@@ -805,6 +815,16 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
 				      virtual_location, 0, message);
         }
 
+      if ((result & CPP_N_SIZE_T) == CPP_N_SIZE_T
+	  && !CPP_OPTION (pfile, size_t_literals))
+       {
+	  const char *message = (result & CPP_N_UNSIGNED) == CPP_N_UNSIGNED
+				? N_("use of C++23 %<size_t%> integer constant")
+				: N_("use of C++23 %<make_signed<size_t>::type%> integer constant");
+	  cpp_warning_with_line (pfile, CPP_W_SIZE_T_LITERALS,
+				 virtual_location, 0, message);
+       }
+
       result |= CPP_N_INTEGER;
     }
 
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index 4467c73..17feb64 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -500,6 +500,9 @@ struct cpp_options
   /* Nonzero means tokenize C++20 module directives.  */
   unsigned char module_directives;
 
+  /* Nonzero for C++23 size_t literals.  */
+  unsigned char size_t_literals;
+
   /* Holds the name of the target (execution) character set.  */
   const char *narrow_charset;
 
@@ -626,6 +629,7 @@ enum cpp_warning_reason {
   CPP_W_INVALID_PCH,
   CPP_W_WARNING_DIRECTIVE,
   CPP_W_LITERAL_SUFFIX,
+  CPP_W_SIZE_T_LITERALS,
   CPP_W_DATE_TIME,
   CPP_W_PEDANTIC,
   CPP_W_C90_C99_COMPAT,
@@ -1211,7 +1215,9 @@ struct cpp_num
 #define CPP_N_FLOATN	0x400000 /* _FloatN types.  */
 #define CPP_N_FLOATNX	0x800000 /* _FloatNx types.  */
 
-#define CPP_N_USERDEF	0x1000000 /* C++0x user-defined literal.  */
+#define CPP_N_USERDEF	0x1000000 /* C++11 user-defined literal.  */
+
+#define CPP_N_SIZE_T	0x2000000 /* C++23 size_t literal.  */
 
 #define CPP_N_WIDTH_FLOATN_NX	0xF0000000 /* _FloatN / _FloatNx value
 					      of N, divided by 16.  */
diff --git a/libcpp/init.c b/libcpp/init.c
index ecd3d5b..17b0d25 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -94,34 +94,35 @@ struct lang_flags
   char va_opt;
   char scope;
   char dfp_constants;
+  char size_t_literals;
 };
 
 static const struct lang_flags lang_defaults[] =
-{ /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt scope dfp */
-  /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0 },
-  /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
-  /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
-  /* GNUC17   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
-  /* GNUC2X   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    1,     0,     0,   1,      1,   1,     1 },
-  /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
-  /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
-  /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
-  /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
-  /* STDC17   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
-  /* STDC2X   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    1,     0,     1,   1,      0,   1,     1 },
-  /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0 },
-  /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   1,     0 },
-  /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0,      1,   1,     0 },
-  /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0,      0,   1,     0 },
-  /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0,      1,   1,     0 },
-  /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0,      0,   1,     0 },
-  /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
-  /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      0,   1,     0 },
-  /* GNUCXX20 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
-  /* CXX20    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
-  /* GNUCXX23 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
-  /* CXX23    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
-  /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0,      0,   0,     0 }
+{ /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt scope dfp szlit */
+  /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0,   0 },
+  /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0,   0 },
+  /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0,   0 },
+  /* GNUC17   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0,   0 },
+  /* GNUC2X   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    1,     0,     0,   1,      1,   1,     1,   0 },
+  /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0 },
+  /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0 },
+  /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0 },
+  /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0 },
+  /* STDC17   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0 },
+  /* STDC2X   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    1,     0,     1,   1,      0,   1,     1,   0 },
+  /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0,   0 },
+  /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   1,     0,   0 },
+  /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0,      1,   1,     0,   0 },
+  /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0,      0,   1,     0,   0 },
+  /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0,      1,   1,     0,   0 },
+  /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0,      0,   1,     0,   0 },
+  /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0 },
+  /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      0,   1,     0,   0 },
+  /* GNUCXX20 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0 },
+  /* CXX20    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0 },
+  /* GNUCXX23 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1 },
+  /* CXX23    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1 },
+  /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0,      0,   0,     0,   0 }
 };
 
 /* Sets internal flags correctly for a given language.  */
@@ -149,6 +150,7 @@ cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
   CPP_OPTION (pfile, va_opt)			 = l->va_opt;
   CPP_OPTION (pfile, scope)			 = l->scope;
   CPP_OPTION (pfile, dfp_constants)		 = l->dfp_constants;
+  CPP_OPTION (pfile, size_t_literals)		 = l->size_t_literals;
 }
 
 /* Initialize library global state.  */