| Message ID | 5061BEC4.7080506@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Tue, Sep 25, 2012 at 04:25:08PM +0200, Florian Weimer wrote: > 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? I can't approve your patch, but I find it useful and wish it would be accepted. Cheers.
>>>>> "Florian" == Florian Weimer <fweimer@redhat.com> writes:
Florian> This patch adds support for #pragma GCC warning and #pragma GCC
Florian> error. These pragmas can be used from preprocessor macros,
Florian> unlike the existing #warning and #error directives. Library
Florian> authors can use these pragmas to add deprecation warnings to
Florian> macros they define.
I'm not sure if my libcpp review powers extend to an extension like
this.
It seems reasonable to me though.
Florian> Index: gcc/doc/cpp.texi
[...]
Florian> +contained in the pragma must be a single string literal. Similary,
Typo, "similarly" -- missing "l".
Florian> +@code{#pragma GCC error "message"} issues an error message. Unlike
Florian> +the @samp{#warning} and @samp{#error} directives provided by
Florian> +compilers, these pragmas can be embedded in preprocessor macros using
I would just remove "provided by compilers".
Florian> + cpp_error (pfile, CPP_DL_ERROR, "invalid #pragma GCC %s directive",
It seems to me that the '#pragma GCC %s' part should have quotes around
it.
Tom
On 9/26/2012 4:19 PM, Tom Tromey wrote: >>>>>> "Florian" == Florian Weimer <fweimer@redhat.com> writes: > > Florian> This patch adds support for #pragma GCC warning and #pragma GCC > Florian> error. These pragmas can be used from preprocessor macros, > Florian> unlike the existing #warning and #error directives. Library > Florian> authors can use these pragmas to add deprecation warnings to > Florian> macros they define. > > I'm not sure if my libcpp review powers extend to an extension like > this. > > It seems reasonable to me though. To me too, these correspond to the Compile_Time_Warning and Compile_Time_Error in Ada, and are definitely very useful!
On 09/26/2012 10:19 PM, Tom Tromey wrote: >>>>>> "Florian" == Florian Weimer <fweimer@redhat.com> writes: > > Florian> This patch adds support for #pragma GCC warning and #pragma GCC > Florian> error. These pragmas can be used from preprocessor macros, > Florian> unlike the existing #warning and #error directives. Library > Florian> authors can use these pragmas to add deprecation warnings to > Florian> macros they define. > > I'm not sure if my libcpp review powers extend to an extension like > this. > > It seems reasonable to me though. Thanks, I'll wait until next week for further feedback. > Florian> Index: gcc/doc/cpp.texi > [...] > Florian> +contained in the pragma must be a single string literal. Similary, > > Typo, "similarly" -- missing "l". Thanks, fixed in my copy. > Florian> +@code{#pragma GCC error "message"} issues an error message. Unlike > Florian> +the @samp{#warning} and @samp{#error} directives provided by > Florian> +compilers, these pragmas can be embedded in preprocessor macros using > > I would just remove "provided by compilers". Yes, it's a bit awkward, and I've removed it. I wanted to stress that these directives aren't part of the preprocessor, to avoid confusion. > Florian> + cpp_error (pfile, CPP_DL_ERROR, "invalid #pragma GCC %s directive", > > It seems to me that the '#pragma GCC %s' part should have quotes around > it. Good. I don't think we've got the magic quotes inside libgcc, so I'm just going with this, following other examples in the file: + cpp_error (pfile, CPP_DL_ERROR, "invalid \"#pragma GCC %s\" directive", + error ? "error" : "warning");
gcc/ChangeLog: 2012-09-25 Florian Weimer <fweimer@redhat.com> * doc/cpp.texi (Pragmas): Document #pragma GCC warning, #pragma GCC error. gcc/testsuite/ChangeLog: 2012-09-25 Florian Weimer <fweimer@redhat.com> * c-c++-common/cpp/diagnostic-pragma-1.c: New testcase. libcpp/ChangeLog: 2012-09-25 Florian Weimer <fweimer@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)