re PR c/61854 (Warning single-line comment for -std=c89?)

PR c/61854
libcpp/
	* init.c (struct lang_flags): Remove cplusplus_comments.
	(cpp_set_lang): Likewise.
	(post_options): Likewise.
	* lex.c (_cpp_lex_direct): Disallow C++ style comments in C90/C94.
testsuite/
	* gcc.dg/cpp/pr61854-1.c: New test.
	* gcc.dg/cpp/pr61854-2.c: New test.
	* gcc.dg/cpp/pr61854-3.c: New test.
	* gcc.dg/cpp/pr61854-3.h: New test.
	* gcc.dg/cpp/pr61854-4.c: New test.
	* gcc.dg/cpp/pr61854-5.c: New test.
	* gcc.dg/cpp/pr61854-6.c: New test.
	* gcc.dg/cpp/pr61854-7.c: New test.
	* gcc.dg/cpp/pr61854-c90.c: New test.
	* gcc.dg/cpp/pr61854-c94.c: New test.

From-SVN: r215339

gcc/testsuite/ChangeLog

@@ -1,3 +1,17 @@
+2014-09-17  Marek Polacek  <polacek@redhat.com>
+
+	PR c/61854
+	* gcc.dg/cpp/pr61854-1.c: New test.
+	* gcc.dg/cpp/pr61854-2.c: New test.
+	* gcc.dg/cpp/pr61854-3.c: New test.
+	* gcc.dg/cpp/pr61854-3.h: New test.
+	* gcc.dg/cpp/pr61854-4.c: New test.
+	* gcc.dg/cpp/pr61854-5.c: New test.
+	* gcc.dg/cpp/pr61854-6.c: New test.
+	* gcc.dg/cpp/pr61854-7.c: New test.
+	* gcc.dg/cpp/pr61854-c90.c: New test.
+	* gcc.dg/cpp/pr61854-c94.c: New test.
+
 2014-09-17  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/63284

gcc/testsuite/gcc.dg/cpp/pr61854-1.c

@@ -0,0 +1,15 @@
+/* PR c/61854 */
+/* { dg-do run } */
+/* { dg-options "-std=c89" } */
+
+int
+main (void)
+{
+  int i = 1 //**/ 2
+  ;
+  int j = 1 //**/ 2
+  ;
+  if (i != 0 || j != 0)
+    __builtin_abort ();  
+  return 0;
+}

gcc/testsuite/gcc.dg/cpp/pr61854-2.c

@@ -0,0 +1,15 @@
+/* PR c/61854 */
+/* { dg-do run } */
+/* { dg-options "-std=gnu89" } */
+
+int
+main (void)
+{
+  int i = 1 //**/ 2
+  ;
+  int j = 1 //**/ 2
+  ;
+  if (i != 1 || j != 1)
+    __builtin_abort ();  
+  return 0;
+}

gcc/testsuite/gcc.dg/cpp/pr61854-3.c

@@ -0,0 +1,6 @@
+/* PR c/61854 */
+/* { dg-do preprocess } */
+/* { dg-options "-std=c89" } */
+
+#include "pr61854-3.h"
+int i;

gcc/testsuite/gcc.dg/cpp/pr61854-3.h

@@ -0,0 +1,4 @@
+#pragma GCC system_header
+// X
+// Y
+// Z

gcc/testsuite/gcc.dg/cpp/pr61854-4.c

@@ -0,0 +1,16 @@
+/* PR c/61854 */
+/* { dg-do preprocess } */
+/* { dg-options "-std=c89" } */
+
+void
+foo (void)
+{
+#if 0
+  // Do not error here.
+#endif
+#if 1
+  // But error here.
+#endif
+  /* { dg-error "C\\+\\+ style comments are not allowed in ISO C90" "comments"  { target *-*-*} 12 } */
+  /* { dg-error "reported only once" ""  { target *-*-*} 12 } */
+}

gcc/testsuite/gcc.dg/cpp/pr61854-5.c

@@ -0,0 +1,15 @@
+/* PR c/61854 */
+/* { dg-do run } */
+/* { dg-options "-std=c89" } */
+
+#define h(x) #x
+#define s(x) h(x)
+#define foo //
+
+int
+main (void)
+{
+  if (__builtin_memcmp (s(foo), "//", 3) != 0)
+    __builtin_abort ();
+  return 0;
+}

gcc/testsuite/gcc.dg/cpp/pr61854-6.c

@@ -0,0 +1,19 @@
+/* PR c/61854 */
+/* { dg-do run } */
+/* { dg-options "-std=gnu89" } */
+
+int
+main (void)
+{
+  int i = 0
+#if 0
+// /*
+#else
+// */
++1
+#endif
+;
+  if (i != 1)
+    __builtin_abort ();
+  return 0;
+}

gcc/testsuite/gcc.dg/cpp/pr61854-7.c

@@ -0,0 +1,19 @@
+/* PR c/61854 */
+/* { dg-do run } */
+/* { dg-options "-std=c89" } */
+
+int
+main (void)
+{
+  int i = 0
+#if 0
+// /*
+#else
+// */
++1
+#endif
+;
+  if (i != 0)
+    __builtin_abort ();
+  return 0;
+}

gcc/testsuite/gcc.dg/cpp/pr61854-c90.c

@@ -0,0 +1,13 @@
+/* PR c/61854 */
+/* { dg-do preprocess } */
+/* { dg-options "-std=iso9899:1990" } */
+
+void
+foo (void)
+{
+  // 1st
+  /* { dg-error "C\\+\\+ style comments are not allowed in ISO C90" "comments"  { target *-*-*} 8 } */
+  /* { dg-error "reported only once" ""  { target *-*-*} 8 } */
+  // 2nd
+  // 3rd
+}

gcc/testsuite/gcc.dg/cpp/pr61854-c94.c

@@ -0,0 +1,13 @@
+/* PR c/61854 */
+/* { dg-do preprocess } */
+/* { dg-options "-std=iso9899:199409" } */
+
+void
+foo (void)
+{
+  // 1st
+  /* { dg-error "C\\+\\+ style comments are not allowed in ISO C90" "comments"  { target *-*-*} 8 } */
+  /* { dg-error "reported only once" ""  { target *-*-*} 8 } */
+  // 2nd
+  // 3rd
+}

libcpp/ChangeLog

@@ -1,3 +1,11 @@
+2014-09-17  Marek Polacek  <polacek@redhat.com>
+
+	PR c/61854
+	* init.c (struct lang_flags): Remove cplusplus_comments.
+	(cpp_set_lang): Likewise.
+	(post_options): Likewise.
+	* lex.c (_cpp_lex_direct): Disallow C++ style comments in C90/C94.
+
 2014-09-09  Manuel López-Ibáñez  <manu@gcc.gnu.org>
 
 	* include/cpplib.h (struct cpp_options): Declare warn_normalize as

libcpp/init.c

@@ -83,7 +83,6 @@ struct lang_flags
   char extended_identifiers;
   char c11_identifiers;
   char std;
-  char cplusplus_comments;
   char digraphs;
   char uliterals;
   char rliterals;
@@ -94,23 +93,23 @@ struct lang_flags
 };
 
 static const struct lang_flags lang_defaults[] =
-{ /*              c99 c++ xnum xid c11 std // digr ulit rlit udlit bincst digsep trig */
+{ /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig */
-  /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,  1,  0,   0,   0,    0,     0,     0 },
+  /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0 },
-  /* GNUC99   */  { 1,  0,  1,  0,  0,  0,  1,  1,  1,   1,   0,    0,     0,     0 },
+  /* GNUC99   */  { 1,  0,  1,  0,  0,  0,  1,   1,   1,   0,    0,     0,     0 },
-  /* GNUC11   */  { 1,  0,  1,  0,  1,  0,  1,  1,  1,   1,   0,    0,     0,     0 },
+  /* GNUC11   */  { 1,  0,  1,  0,  1,  0,  1,   1,   1,   0,    0,     0,     0 },
-  /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,  0,  0,   0,   0,    0,     0,     1 },
+  /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1 },
-  /* STDC94   */  { 0,  0,  0,  0,  0,  1,  0,  1,  0,   0,   0,    0,     0,     1 },
+  /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
-  /* STDC99   */  { 1,  0,  1,  0,  0,  1,  1,  1,  0,   0,   0,    0,     0,     1 },
+  /* STDC99   */  { 1,  0,  1,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
-  /* STDC11   */  { 1,  0,  1,  0,  1,  1,  1,  1,  1,   0,   0,    0,     0,     1 },
+  /* STDC11   */  { 1,  0,  1,  0,  1,  1,  1,   1,   0,   0,    0,     0,     1 },
-  /* GNUCXX   */  { 0,  1,  1,  0,  0,  0,  1,  1,  0,   0,   0,    0,     0,     0 },
+  /* GNUCXX   */  { 0,  1,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0 },
-  /* CXX98    */  { 0,  1,  0,  0,  0,  1,  1,  1,  0,   0,   0,    0,     0,     1 },
+  /* CXX98    */  { 0,  1,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1 },
-  /* GNUCXX11 */  { 1,  1,  1,  0,  1,  0,  1,  1,  1,   1,   1,    0,     0,     0 },
+  /* GNUCXX11 */  { 1,  1,  1,  0,  1,  0,  1,   1,   1,   1,    0,     0,     0 },
-  /* CXX11    */  { 1,  1,  1,  0,  1,  1,  1,  1,  1,   1,   1,    0,     0,     1 },
+  /* CXX11    */  { 1,  1,  1,  0,  1,  1,  1,   1,   1,   1,    0,     0,     1 },
-  /* GNUCXX14 */  { 1,  1,  1,  0,  1,  0,  1,  1,  1,   1,   1,    1,     1,     0 },
+  /* GNUCXX14 */  { 1,  1,  1,  0,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
-  /* CXX14    */  { 1,  1,  1,  0,  1,  1,  1,  1,  1,   1,   1,    1,     1,     1 },
+  /* CXX14    */  { 1,  1,  1,  0,  1,  1,  1,   1,   1,   1,    1,     1,     1 },
-  /* GNUCXX1Z */  { 1,  1,  1,  0,  1,  0,  1,  1,  1,   1,   1,    1,     1,     0 },
+  /* GNUCXX1Z */  { 1,  1,  1,  0,  1,  0,  1,   1,   1,   1,    1,     1,     0 },
-  /* CXX1Z    */  { 1,  1,  1,  0,  1,  1,  1,  1,  1,   1,   1,    1,     1,     0 },
+  /* CXX1Z    */  { 1,  1,  1,  0,  1,  1,  1,   1,   1,   1,    1,     1,     0 },
-  /* ASM      */  { 0,  0,  1,  0,  0,  0,  1,  0,  0,   0,   0,    0,     0,     0 }
+  /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0 }
   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX11, CXX11,
      GNUCXX14, and CXX14 when no longer experimental (when all uses of
      identifiers in the compiler have been audited for correct handling
@@ -131,7 +130,6 @@ cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
   CPP_OPTION (pfile, extended_identifiers)	 = l->extended_identifiers;
   CPP_OPTION (pfile, c11_identifiers)		 = l->c11_identifiers;
   CPP_OPTION (pfile, std)			 = l->std;
-  CPP_OPTION (pfile, cplusplus_comments)	 = l->cplusplus_comments;
   CPP_OPTION (pfile, digraphs)			 = l->digraphs;
   CPP_OPTION (pfile, uliterals)			 = l->uliterals;
   CPP_OPTION (pfile, rliterals)			 = l->rliterals;
@@ -775,8 +773,6 @@ post_options (cpp_reader *pfile)
 
   if (CPP_OPTION (pfile, traditional))
     {
-      CPP_OPTION (pfile, cplusplus_comments) = 0;
-
       CPP_OPTION (pfile, trigraphs) = 0;
       CPP_OPTION (pfile, warn_trigraphs) = 0;
     }

libcpp/lex.c

@@ -2322,12 +2322,15 @@ _cpp_lex_direct (cpp_reader *pfile)
 	  if (_cpp_skip_block_comment (pfile))
 	    cpp_error (pfile, CPP_DL_ERROR, "unterminated comment");
 	}
-      else if (c == '/' && (CPP_OPTION (pfile, cplusplus_comments)
+      else if (c == '/' && ! CPP_OPTION (pfile, traditional))
-			    || cpp_in_system_header (pfile)))
 	{
+	  /* Don't warn for system headers.  */
+	  if (cpp_in_system_header (pfile))
+	    ;
 	  /* Warn about comments if pedantically GNUC89, and not
 	     in system headers.  */
-	  if (CPP_OPTION (pfile, lang) == CLK_GNUC89 && CPP_PEDANTIC (pfile)
+	  else if (CPP_OPTION (pfile, lang) == CLK_GNUC89
+		   && CPP_PEDANTIC (pfile)
 		   && ! buffer->warned_cplusplus_comments)
 	    {
 	      cpp_error (pfile, CPP_DL_PEDWARN,
@@ -2347,7 +2350,31 @@ _cpp_lex_direct (cpp_reader *pfile)
 			 "(this will be reported only once per input file)");
 	      buffer->warned_cplusplus_comments = 1;
 	    }
-
+	  /* In C89/C94, C++ style comments are forbidden.  */
+	  else if ((CPP_OPTION (pfile, lang) == CLK_STDC89
+		    || CPP_OPTION (pfile, lang) == CLK_STDC94))
+	    {
+	      /* But don't be confused about valid code such as
+	         - // immediately followed by *,
+		 - // in a preprocessing directive,
+		 - // in an #if 0 block.  */
+	      if (buffer->cur[1] == '*'
+		  || pfile->state.in_directive
+		  || pfile->state.skipping)
+		{
+		  result->type = CPP_DIV;
+		  break;
+		}
+	      else if (! buffer->warned_cplusplus_comments)
+		{
+		  cpp_error (pfile, CPP_DL_ERROR,
+			     "C++ style comments are not allowed in ISO C90");
+		  cpp_error (pfile, CPP_DL_ERROR,
+			     "(this will be reported only once per input "
+			     "file)");
+		  buffer->warned_cplusplus_comments = 1;
+		}
+	    }
 	  if (skip_line_comment (pfile) && CPP_OPTION (pfile, warn_comments))
 	    cpp_warning (pfile, CPP_W_COMMENTS, "multi-line comment");
 	}