This patch adds support for #pragma GCC warning and #pragma GCC error.
These pragmas can be used from preprocessor macros, unlike the existing
#warning and #error directives. Library authors can use these pragmas
to add deprecation warnings to macros they define.
Bootstrapped and tested on x86_64-redhat-linux-gnu, with no apparent
regressions. Okay for trunk?
--
Florian Weimer / Red Hat Product Security Team
gcc/ChangeLog:
2012-09-25 Florian Weimer <fwei...@redhat.com>
* doc/cpp.texi (Pragmas): Document #pragma GCC warning, #pragma
GCC error.
gcc/testsuite/ChangeLog:
2012-09-25 Florian Weimer <fwei...@redhat.com>
* c-c++-common/cpp/diagnostic-pragma-1.c: New testcase.
libcpp/ChangeLog:
2012-09-25 Florian Weimer <fwei...@redhat.com>
* directives.c (do_pragma_warning_or_error): New.
(do_pragma_warning): New.
(do_pragma_error): New.
(_cpp_init_internal_pragmas): Register new pragmas.
Index: gcc/doc/cpp.texi
===================================================================
--- gcc/doc/cpp.texi (revision 191700)
+++ gcc/doc/cpp.texi (working copy)
@@ -3634,6 +3634,16 @@
current file to be treated as if it came from a system header.
@xref{System Headers}.
+@item #pragma GCC warning
+@itemx #pragma GCC error
+@code{#pragma GCC warning "message"} causes the preprocessor to issue
+a warning diagnostic with the text @samp{message}. The message
+contained in the pragma must be a single string literal. Similary,
+@code{#pragma GCC error "message"} issues an error message. Unlike
+the @samp{#warning} and @samp{#error} directives provided by
+compilers, these pragmas can be embedded in preprocessor macros using
+@samp{_Pragma}.
+
@end ftable
@node Other Directives
Index: gcc/testsuite/c-c++-common/cpp/diagnostic-pragma-1.c
===================================================================
--- gcc/testsuite/c-c++-common/cpp/diagnostic-pragma-1.c (revision 0)
+++ gcc/testsuite/c-c++-common/cpp/diagnostic-pragma-1.c (working copy)
@@ -0,0 +1,11 @@
+// { dg-do compile }
+
+#pragma GCC warning "warn-a" // { dg-warning warn-a }
+#pragma GCC error "err-b" // { dg-error err-b }
+
+#define CONST1 _Pragma("GCC warning \"warn-c\"") 1
+#define CONST2 _Pragma("GCC error \"err-d\"") 2
+
+char a[CONST1]; // { dg-warning warn-c }
+char b[CONST2]; // { dg-error err-d }
+
Index: libcpp/directives.c
===================================================================
--- libcpp/directives.c (revision 191700)
+++ libcpp/directives.c (working copy)
@@ -1,7 +1,5 @@
/* CPP Library. (Directive handling.)
- Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003, 2004, 2005,
- 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+ Copyright (C) 1986-2012 Free Software Foundation, Inc.
Contributed by Per Bothner, 1994-95.
Based on CCCP program by Paul Rubin, June 1986
Adapted to ANSI C, Richard Stallman, Jan 1987
@@ -118,6 +116,9 @@
static void do_pragma_poison (cpp_reader *);
static void do_pragma_system_header (cpp_reader *);
static void do_pragma_dependency (cpp_reader *);
+static void do_pragma_warning_or_error (cpp_reader *, bool error);
+static void do_pragma_warning (cpp_reader *);
+static void do_pragma_error (cpp_reader *);
static void do_linemarker (cpp_reader *);
static const cpp_token *get_token_no_padding (cpp_reader *);
static const cpp_token *get__Pragma_string (cpp_reader *);
@@ -1263,6 +1264,8 @@
register_pragma_internal (pfile, "GCC", "system_header",
do_pragma_system_header);
register_pragma_internal (pfile, "GCC", "dependency", do_pragma_dependency);
+ register_pragma_internal (pfile, "GCC", "warning", do_pragma_warning);
+ register_pragma_internal (pfile, "GCC", "error", do_pragma_error);
}
/* Return the number of registered pragmas in PE. */
@@ -1634,6 +1637,42 @@
free ((void *) fname);
}
+/* Issue a diagnostic with the message taken from the pragma. If
+ ERROR is true, the diagnostic is a warning, otherwise, it is an
+ error. */
+static void
+do_pragma_warning_or_error (cpp_reader *pfile, bool error)
+{
+ const cpp_token *tok = _cpp_lex_token (pfile);
+ cpp_string str;
+ if (tok->type != CPP_STRING
+ || !cpp_interpret_string_notranslate (pfile, &tok->val.str, 1, &str,
+ CPP_STRING)
+ || str.len == 0)
+ {
+ cpp_error (pfile, CPP_DL_ERROR, "invalid #pragma GCC %s directive",
+ error ? "error" : "warning");
+ return;
+ }
+ cpp_error (pfile, error ? CPP_DL_ERROR : CPP_DL_WARNING,
+ "%s", str.text);
+ free ((void *)str.text);
+}
+
+/* Issue a warning diagnostic. */
+static void
+do_pragma_warning (cpp_reader *pfile)
+{
+ do_pragma_warning_or_error (pfile, false);
+}
+
+/* Issue an error diagnostic. */
+static void
+do_pragma_error (cpp_reader *pfile)
+{
+ do_pragma_warning_or_error (pfile, true);
+}
+
/* Get a token but skip padding. */
static const cpp_token *
get_token_no_padding (cpp_reader *pfile)
