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From: Jakub Jelinek <jakub@redhat.com>
To: Jason Merrill <jason@redhat.com>, Joseph Myers <joseph@codesourcery.com>
Cc: gcc-patches@gcc.gnu.org, Marek Polacek <polacek@redhat.com>
Subject: [PATCH] preprocessor: Implement C++23 P2437R1 - Support for #warning [PR106646]
Date: Mon, 22 Aug 2022 11:53:33 +0200	[thread overview]
Message-ID: <YwNSHY8mx41NB1jF@tucnak> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2208182301330.72069@digraph.polyomino.org.uk>

Hi!

On Thu, Aug 18, 2022 at 11:02:44PM +0000, Joseph Myers wrote:
> ISO C2x standardizes the existing #warning extension.  Arrange
> accordingly for it not to be diagnosed with -std=c2x -pedantic, but to
> be diagnosed with -Wc11-c2x-compat.

And here is the corresponding C++ version.
Don't pedwarn about this for C++23/GNU++23 and tweak the diagnostics
for C++ otherwise, + testsuite coverage.
The diagnostic wording is similar e.g. to the #elifdef diagnostics.

So far lightly tested, ok for trunk if it passes full bootstrap/regtest?

2022-08-22  Jakub Jelinek  <jakub@redhat.com>

	PR c++/106646
	* init.cc: Implement C++23 P2437R1 - Support for #warning.
	(lang_defaults): Set warning_directive for GNUCXX23 and CXX23.
	* directives.cc (directive_diagnostics): Use different wording of
	#warning pedwarn for C++.

	* g++.dg/cpp/warning-1.C: New test.
	* g++.dg/cpp/warning-2.C: New test.
	* g++.dg/cpp/warning-3.C: New test.

--- libcpp/init.cc.jj	2022-08-20 10:25:17.613071845 +0200
+++ libcpp/init.cc	2022-08-22 11:30:57.642622570 +0200
@@ -123,8 +123,8 @@ static const struct lang_flags lang_defa
   /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      0,   1,     0,   0,   0,      0,      0 },
   /* GNUCXX20 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0,   0,      0,      0 },
   /* CXX20    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0,   0,      0,      0 },
-  /* GNUCXX23 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1,   1,      0,      1 },
-  /* CXX23    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1,   1,      0,      1 },
+  /* GNUCXX23 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1,   1,      1,      1 },
+  /* CXX23    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1,   1,      1,      1 },
   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0,      0,   0,     0,   0,   0,      0,      0 }
 };
 
--- libcpp/directives.cc.jj	2022-08-19 16:00:05.295386974 +0200
+++ libcpp/directives.cc	2022-08-22 11:30:03.239357642 +0200
@@ -388,8 +388,14 @@ directive_diagnostics (cpp_reader *pfile
       else if (dir == &dtable[T_WARNING])
 	{
 	  if (CPP_PEDANTIC (pfile) && !CPP_OPTION (pfile, warning_directive))
-	    cpp_error (pfile, CPP_DL_PEDWARN,
-		       "#%s before C2X is a GCC extension", dir->name);
+	    {
+	      if (CPP_OPTION (pfile, cplusplus))
+		cpp_error (pfile, CPP_DL_PEDWARN,
+			   "#%s before C++23 is a GCC extension", dir->name);
+	      else
+		cpp_error (pfile, CPP_DL_PEDWARN,
+			   "#%s before C2X is a GCC extension", dir->name);
+	    }
 	  else if (CPP_OPTION (pfile, cpp_warn_c11_c2x_compat) > 0)
 	    cpp_warning (pfile, CPP_W_C11_C2X_COMPAT,
 			 "#%s before C2X is a GCC extension", dir->name);
--- gcc/testsuite/g++.dg/cpp/warning-1.C.jj	2022-08-22 11:39:41.284547323 +0200
+++ gcc/testsuite/g++.dg/cpp/warning-1.C	2022-08-22 11:44:03.925988332 +0200
@@ -0,0 +1,6 @@
+// P2437R1 - Support for #warning
+// { dg-do preprocess }
+// { dg-options "-pedantic-errors" }
+
+#warning example text /* { dg-warning "example text" } */
+// { dg-error "#warning before C\\\+\\\+23 is a GCC extension" "pedantic" { target c++20_down } .-1 }
--- gcc/testsuite/g++.dg/cpp/warning-2.C.jj	2022-08-22 11:39:44.116509055 +0200
+++ gcc/testsuite/g++.dg/cpp/warning-2.C	2022-08-22 11:44:14.933839041 +0200
@@ -0,0 +1,6 @@
+// P2437R1 - Support for #warning
+// { dg-do preprocess }
+// { dg-options "-pedantic" }
+
+#warning example text /* { dg-warning "example text" } */
+// { dg-warning "#warning before C\\\+\\\+23 is a GCC extension" "pedantic" { target c++20_down } .-1 }
--- gcc/testsuite/g++.dg/cpp/warning-3.C.jj	2022-08-22 11:39:47.020469826 +0200
+++ gcc/testsuite/g++.dg/cpp/warning-3.C	2022-08-22 11:42:23.640348405 +0200
@@ -0,0 +1,6 @@
+// P2437R1 - Support for #warning
+// { dg-do preprocess }
+// { dg-options "" }
+
+#warning example text /* { dg-warning "example text" } */
+// { dg-bogus "#warning before C\\\+\\\+23 is a GCC extension" "" { target *-*-* } .-1 }


	Jakub


  reply	other threads:[~2022-08-22  9:53 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-18 23:02 [committed] preprocessor: Support #warning for standard C2x Joseph Myers
2022-08-22  9:53 ` Jakub Jelinek [this message]
2022-08-23 21:54   ` [PATCH] preprocessor: Implement C++23 P2437R1 - Support for #warning [PR106646] Jason Merrill

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