* [PATCH] cpp/c: Add -Wexpansion-to-defined
@ 2016-08-09 16:00 Paolo Bonzini
2016-08-09 18:30 ` Manuel López-Ibáñez
2016-08-09 18:44 ` Eric Gallager
0 siblings, 2 replies; 7+ messages in thread
From: Paolo Bonzini @ 2016-08-09 16:00 UTC (permalink / raw)
To: gcc-patches
clang recently added a new warning -Wexpansion-to-defined, which
warns when `defined' is used outside a #if expression (including the
case of a macro that is then used in a #if expression).
While I disagree with their inclusion of the warning to -Wall, I think
it is a good addition overall. First, it is a logical extension of the
existing warning for breaking defined across a macro and its caller.
Second, it is good to make these warnings for `defined' available with
a command-line option other than -pedantic.
This patch adds -Wexpansion-to-defined, and enables it automatically
for both -pedantic (as before) and -Wextra.
Bootstrapped and regression tested x86_64-pc-linux-gnu, ok?
Paolo
libcpp:
2016-08-09 Paolo Bonzini <bonzini@gnu.org>
* include/cpplib.h (struct cpp_options): Add new member
warn_expansion_to_defined.
(CPP_W_EXPANSION_TO_DEFINED): New enum member.
* expr.c (parse_defined): Warn for all uses of "defined"
in macros, and tie warning to CPP_W_EXPANSION_TO_DEFINED.
* system.h (HAVE_DESIGNATED_INITIALIZERS): Do not use
"defined" in macros.
gcc:
2016-08-09 Paolo Bonzini <bonzini@gnu.org>
* system.h (HAVE_DESIGNATED_INITIALIZERS,
HAVE_DESIGNATED_UNION_INITIALIZERS): Do not use
"defined" in macros.
gcc/c-family:
2016-08-09 Paolo Bonzini <bonzini@gnu.org>
* c-opts (sanitize_cpp_opts): Compute default value
for -Wexpansion-to-defined.
* c.opt (Wexpansion-to-defined): New.
gcc/doc:
2016-08-09 Paolo Bonzini <bonzini@gnu.org>
* cpp.texi (Defined): Mention -Wexpansion-to-defined.
* cppopts.texi (Invocation): Document -Wexpansion-to-defined.
* invoke.texi (Warning Options): Document -Wexpansion-to-defined.
gcc/testsuite:
2016-08-09 Paolo Bonzini <bonzini@gnu.org>
* gcc.dg/cpp/defined.c: Mark newly introduced warnings.
* gcc.dg/cpp/defined-Wexpansion-to-defined.c,
gcc.dg/cpp/defined-Wextra-Wno-expansion-to-defined.c,
gcc.dg/cpp/defined-Wextra.c,
gcc.dg/cpp/defined-Wno-expansion-to-defined.c: New testcases.
Index: gcc/c-family/c-opts.c
===================================================================
--- gcc/c-family/c-opts.c (revision 239276)
+++ gcc/c-family/c-opts.c (working copy)
@@ -1256,6 +1256,10 @@ sanitize_cpp_opts (void)
cpp_opts->unsigned_char = !flag_signed_char;
cpp_opts->stdc_0_in_system_headers = STDC_0_IN_SYSTEM_HEADERS;
+ cpp_opts->warn_expansion_to_defined = cpp_warn_expansion_to_defined;
+ if (cpp_warn_expansion_to_defined == -1)
+ cpp_warn_expansion_to_defined = pedantic || extra_warnings;
+
/* Wlong-long is disabled by default. It is enabled by:
[-Wpedantic | -Wtraditional] -std=[gnu|c]++98 ; or
[-Wpedantic | -Wtraditional] -std=non-c99
Index: gcc/c-family/c.opt
===================================================================
--- gcc/c-family/c.opt (revision 239276)
+++ gcc/c-family/c.opt (working copy)
@@ -506,6 +506,10 @@ Wdouble-promotion
C ObjC C++ ObjC++ Var(warn_double_promotion) Warning
Warn about implicit conversions from \"float\" to \"double\".
+Wexpansion-to-defined
+C ObjC C++ ObjC++ CppReason(CPP_W_EXPANSION_TO_DEFINED) Var(cpp_warn_expansion_to_defined) Init(-1) Warning
+Warn if an undefined macro is used in an #if directive.
+
Wimplicit-function-declaration
C ObjC Var(warn_implicit_function_declaration) Init(-1) Warning LangEnabledBy(C ObjC,Wimplicit)
Warn about implicit function declarations.
Index: gcc/doc/cpp.texi
===================================================================
--- gcc/doc/cpp.texi (revision 239276)
+++ gcc/doc/cpp.texi (working copy)
@@ -3342,7 +3342,8 @@ If the @code{defined} operator appears as a result
the C standard says the behavior is undefined. GNU cpp treats it as a
genuine @code{defined} operator and evaluates it normally. It will warn
wherever your code uses this feature if you use the command-line option
-@option{-pedantic}, since other compilers may handle it differently.
+@option{-pedantic}, since other compilers may handle it differently. The
+warning can also be enabled individually with @option{-Wexpansion-to-defined}.
@node Else
@subsection Else
Index: gcc/doc/cppopts.texi
===================================================================
--- gcc/doc/cppopts.texi (revision 239276)
+++ gcc/doc/cppopts.texi (working copy)
@@ -120,6 +120,12 @@ Warn whenever an identifier which is not a macro i
@samp{#if} directive, outside of @samp{defined}. Such identifiers are
replaced with zero.
+@item -Wexpansion-to-defined
+@opindex Wexpansion-to-defined
+Warn whenever @samp{defined} is encountered in the expansion of a macro
+(including the case where the macro is expanded by an @samp{#if} directive).
+Such usage is not portable.
+
@item -Wunused-macros
@opindex Wunused-macros
Warn about macros defined in the main file that are unused. A macro
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 239276)
+++ gcc/doc/invoke.texi (working copy)
@@ -4914,6 +4914,11 @@ Warn when a declaration is found after a statement
construct, known from C++, was introduced with ISO C99 and is by default
allowed in GCC@. It is not supported by ISO C90. @xref{Mixed Declarations}.
+@item -Wexpansion-to-defined
+@opindex Wexpansion-to-defined
+Warn whenever @samp{defined} is encountered in the expansion of a macro.
+This warning is also enabled by @option{-Wpedantic} and @option{-Wextra}.
+
@item -Wundef
@opindex Wundef
@opindex Wno-undef
Index: gcc/system.h
===================================================================
--- gcc/system.h (revision 239276)
+++ gcc/system.h (working copy)
@@ -577,16 +577,22 @@ extern int vsnprintf (char *, size_t, const char *
/* 1 if we have C99 designated initializers. */
#if !defined(HAVE_DESIGNATED_INITIALIZERS)
+#ifdef __cplusplus
+#define HAVE_DESIGNATED_INITIALIZERS 0
+#else
#define HAVE_DESIGNATED_INITIALIZERS \
- (((GCC_VERSION >= 2007) || (__STDC_VERSION__ >= 199901L)) \
- && !defined(__cplusplus))
+ (((GCC_VERSION >= 2007) || (__STDC_VERSION__ >= 199901L))
#endif
+#endif
#if !defined(HAVE_DESIGNATED_UNION_INITIALIZERS)
+#ifdef __cplusplus
+#define HAVE_DESIGNATED_UNION_INITIALIZERS (GCC_VERSION >= 4007)
+#else
#define HAVE_DESIGNATED_UNION_INITIALIZERS \
- (((GCC_VERSION >= 2007) || (__STDC_VERSION__ >= 199901L)) \
- && (!defined(__cplusplus) || (GCC_VERSION >= 4007)))
+ (((GCC_VERSION >= 2007) || (__STDC_VERSION__ >= 199901L))
#endif
+#endif
#if HAVE_SYS_STAT_H
# include <sys/stat.h>
Index: gcc/testsuite/gcc.dg/cpp/defined-Wexpansion-to-defined.c
===================================================================
--- gcc/testsuite/gcc.dg/cpp/defined-Wexpansion-to-defined.c (revision 0)
+++ gcc/testsuite/gcc.dg/cpp/defined-Wexpansion-to-defined.c (working copy)
@@ -0,0 +1,30 @@
+/* Copyright (C) 2000 Free Software Foundation, Inc. */
+
+/* { dg-do preprocess } */
+/* { dg-options "-Wexpansion-to-defined" } */
+
+/* Use of defined in different contexts. */
+
+/* Source: Neil Booth, 29 Oct 2000, Zack Weinberg 11 Dec 2000. */
+
+#define Z
+
+#define bad0 defined Z
+#if !bad0 /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad1 defined
+#if !bad1 Z /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
+#if !bad1 (Z) /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad2 defined (Z
+#if !bad2) /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
Index: gcc/testsuite/gcc.dg/cpp/defined-Wextra-Wno-expansion-to-defined.c
===================================================================
--- gcc/testsuite/gcc.dg/cpp/defined-Wextra-Wno-expansion-to-defined.c (revision 0)
+++ gcc/testsuite/gcc.dg/cpp/defined-Wextra-Wno-expansion-to-defined.c (working copy)
@@ -0,0 +1,30 @@
+/* Copyright (C) 2000 Free Software Foundation, Inc. */
+
+/* { dg-do preprocess } */
+/* { dg-options "-Wextra -Wno-expansion-to-defined" } */
+
+/* Use of defined in different contexts. */
+
+/* Source: Neil Booth, 29 Oct 2000, Zack Weinberg 11 Dec 2000. */
+
+#define Z
+
+#define bad0 defined Z
+#if !bad0 /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad1 defined
+#if !bad1 Z /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
+#if !bad1 (Z) /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad2 defined (Z
+#if !bad2) /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
Index: gcc/testsuite/gcc.dg/cpp/defined-Wextra.c
===================================================================
--- gcc/testsuite/gcc.dg/cpp/defined-Wextra.c (revision 0)
+++ gcc/testsuite/gcc.dg/cpp/defined-Wextra.c (working copy)
@@ -0,0 +1,30 @@
+/* Copyright (C) 2000 Free Software Foundation, Inc. */
+
+/* { dg-do preprocess } */
+/* { dg-options "-Wextra" } */
+
+/* Use of defined in different contexts. */
+
+/* Source: Neil Booth, 29 Oct 2000, Zack Weinberg 11 Dec 2000. */
+
+#define Z
+
+#define bad0 defined Z
+#if !bad0 /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad1 defined
+#if !bad1 Z /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
+#if !bad1 (Z) /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad2 defined (Z
+#if !bad2) /* { dg-warning "may not be portable" } */
+#error Z is defined
+#endif
+
Index: gcc/testsuite/gcc.dg/cpp/defined-Wno-expansion-to-defined.c
===================================================================
--- gcc/testsuite/gcc.dg/cpp/defined-Wno-expansion-to-defined.c (revision 0)
+++ gcc/testsuite/gcc.dg/cpp/defined-Wno-expansion-to-defined.c (working copy)
@@ -0,0 +1,30 @@
+/* Copyright (C) 2000 Free Software Foundation, Inc. */
+
+/* { dg-do preprocess } */
+/* { dg-options "-ansi -pedantic-errors -Wno-expansion-to-defined" } */
+
+/* Use of defined in different contexts. */
+
+/* Source: Neil Booth, 29 Oct 2000, Zack Weinberg 11 Dec 2000. */
+
+#define Z
+
+#define bad0 defined Z
+#if !bad0 /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad1 defined
+#if !bad1 Z /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
+#if !bad1 (Z) /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
+#define bad2 defined (Z
+#if !bad2) /* { dg-bogus "may not be portable" } */
+#error Z is defined
+#endif
+
Index: gcc/testsuite/gcc.dg/cpp/defined.c
===================================================================
--- gcc/testsuite/gcc.dg/cpp/defined.c (revision 239276)
+++ gcc/testsuite/gcc.dg/cpp/defined.c (working copy)
@@ -21,7 +21,7 @@
/* The behavior of "defined" when it comes from a macro expansion is
now documented. */
-#if is_Z_defined
+#if is_Z_defined /* { dg-warning "may not be portable" } */
#error Macro expanding into defined operator test 1
#endif
@@ -31,7 +31,7 @@
#error Z is defined
#endif
-#if !is_Z_defined
+#if !is_Z_defined /* { dg-warning "may not be portable" } */
#error Macro expanding into defined operator test 2
#endif
@@ -53,7 +53,7 @@
/* The behavior of "defined" when it comes from a macro expansion is
now documented. */
-#if is_Z_defined
+#if is_Z_defined /* { dg-warning "may not be portable" } */
#error Macro expanding into defined operator test 1
#endif
@@ -63,7 +63,7 @@
#error Z is defined
#endif
-#if !is_Z_defined
+#if !is_Z_defined /* { dg-warning "may not be portable" } */
#error Macro expanding into defined operator test 2
#endif
Index: libcpp/expr.c
===================================================================
--- libcpp/expr.c (revision 239276)
+++ libcpp/expr.c (working copy)
@@ -947,9 +947,11 @@ parse_defined (cpp_reader *pfile)
if (node)
{
- if (pfile->context != initial_context && CPP_PEDANTIC (pfile))
- cpp_error (pfile, CPP_DL_WARNING,
- "this use of \"defined\" may not be portable");
+ if ((pfile->context != initial_context
+ || initial_context != &pfile->base_context)
+ && CPP_OPTION (pfile, warn_expansion_to_defined))
+ cpp_warning (pfile, CPP_W_EXPANSION_TO_DEFINED,
+ "this use of \"defined\" may not be portable");
_cpp_mark_macro_used (node);
if (!(node->flags & NODE_USED))
Index: libcpp/include/cpplib.h
===================================================================
--- libcpp/include/cpplib.h (revision 239276)
+++ libcpp/include/cpplib.h (working copy)
@@ -410,6 +410,10 @@ struct cpp_options
/* Nonzero means warn if undefined identifiers are evaluated in an #if. */
unsigned char warn_undef;
+ /* Nonzero means warn if "defined" is encountered in a place other than
+ an #if. */
+ unsigned char warn_expansion_to_defined;
+
/* Nonzero means warn of unused macros from the main file. */
unsigned char warn_unused_macros;
@@ -1025,7 +1029,8 @@ enum {
CPP_W_DATE_TIME,
CPP_W_PEDANTIC,
CPP_W_C90_C99_COMPAT,
- CPP_W_CXX11_COMPAT
+ CPP_W_CXX11_COMPAT,
+ CPP_W_EXPANSION_TO_DEFINED
};
/* Output a diagnostic of some kind. */
Index: libcpp/system.h
===================================================================
--- libcpp/system.h (revision 239276)
+++ libcpp/system.h (working copy)
@@ -375,10 +375,13 @@ extern void abort (void);
??? C99 designated initializers are not supported by most C++
compilers, including G++. -- gdr, 2005-05-18 */
#if !defined(HAVE_DESIGNATED_INITIALIZERS)
+#ifdef __cplusplus
+#define HAVE_DESIGNATED_INITIALIZERS 0
+#else
#define HAVE_DESIGNATED_INITIALIZERS \
- (!defined(__cplusplus) \
- && ((GCC_VERSION >= 2007) || (__STDC_VERSION__ >= 199901L)))
+ ((GCC_VERSION >= 2007) || (__STDC_VERSION__ >= 199901L))
#endif
+#endif
#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *) 0)->MEMBER)
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] cpp/c: Add -Wexpansion-to-defined
2016-08-09 16:00 [PATCH] cpp/c: Add -Wexpansion-to-defined Paolo Bonzini
@ 2016-08-09 18:30 ` Manuel López-Ibáñez
2016-08-09 21:21 ` Paolo Bonzini
2016-08-09 18:44 ` Eric Gallager
1 sibling, 1 reply; 7+ messages in thread
From: Manuel López-Ibáñez @ 2016-08-09 18:30 UTC (permalink / raw)
To: Paolo Bonzini, GCC Patches
On 09/08/16 16:59, Paolo Bonzini wrote:
> Index: gcc/c-family/c-opts.c
> ===================================================================
> --- gcc/c-family/c-opts.c (revision 239276)
> +++ gcc/c-family/c-opts.c (working copy)
> @@ -1256,6 +1256,10 @@ sanitize_cpp_opts (void)
> cpp_opts->unsigned_char = !flag_signed_char;
> cpp_opts->stdc_0_in_system_headers = STDC_0_IN_SYSTEM_HEADERS;
>
> + cpp_opts->warn_expansion_to_defined = cpp_warn_expansion_to_defined;
> + if (cpp_warn_expansion_to_defined == -1)
> + cpp_warn_expansion_to_defined = pedantic || extra_warnings;
> +
Instead of the above, plase use LangEnabledBy() or EnabledBy() in c.opt. See
Wendif-labels and other examples. Then, you do not need Init(-1).
> /* Wlong-long is disabled by default. It is enabled by:
> [-Wpedantic | -Wtraditional] -std=[gnu|c]++98 ; or
> [-Wpedantic | -Wtraditional] -std=non-c99
> Index: gcc/c-family/c.opt
> ===================================================================
> --- gcc/c-family/c.opt (revision 239276)
> +++ gcc/c-family/c.opt (working copy)
> @@ -506,6 +506,10 @@ Wdouble-promotion
> C ObjC C++ ObjC++ Var(warn_double_promotion) Warning
> Warn about implicit conversions from \"float\" to \"double\".
>
> +Wexpansion-to-defined
> +C ObjC C++ ObjC++ CppReason(CPP_W_EXPANSION_TO_DEFINED) Var(cpp_warn_expansion_to_defined) Init(-1) Warning
> +Warn if an undefined macro is used in an #if directive.
> +
You are also missing CPP(warn_expansion_to_defined) so that the cpp and gcc
sides are in sync even when using pragmas.
Cheers,
Manuel.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] cpp/c: Add -Wexpansion-to-defined
2016-08-09 16:00 [PATCH] cpp/c: Add -Wexpansion-to-defined Paolo Bonzini
2016-08-09 18:30 ` Manuel López-Ibáñez
@ 2016-08-09 18:44 ` Eric Gallager
2016-08-09 21:35 ` Paolo Bonzini
1 sibling, 1 reply; 7+ messages in thread
From: Eric Gallager @ 2016-08-09 18:44 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: gcc-patches
Hi, I'm just a lurker, but...
On 8/9/16, Paolo Bonzini <bonzini@gnu.org> wrote:
> Index: gcc/c-family/c.opt
> ===================================================================
> --- gcc/c-family/c.opt (revision 239276)
> +++ gcc/c-family/c.opt (working copy)
> @@ -506,6 +506,10 @@ Wdouble-promotion
> C ObjC C++ ObjC++ Var(warn_double_promotion) Warning
> Warn about implicit conversions from \"float\" to \"double\".
>
> +Wexpansion-to-defined
> +C ObjC C++ ObjC++ CppReason(CPP_W_EXPANSION_TO_DEFINED)
> Var(cpp_warn_expansion_to_defined) Init(-1) Warning
> +Warn if an undefined macro is used in an #if directive.
> +
Isn't "Warn if an undefined macro is used in an #if directive" the
same description that -Wundef uses in c.opt? Did you copy and paste
and forget to update that part?
Eric
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] cpp/c: Add -Wexpansion-to-defined
2016-08-09 18:30 ` Manuel López-Ibáñez
@ 2016-08-09 21:21 ` Paolo Bonzini
2016-08-10 0:49 ` Manuel López-Ibáñez
0 siblings, 1 reply; 7+ messages in thread
From: Paolo Bonzini @ 2016-08-09 21:21 UTC (permalink / raw)
To: Manuel López-Ibáñez, GCC Patches
On 09/08/2016 20:30, Manuel López-Ibáñez wrote:
>>
>>
>> + cpp_opts->warn_expansion_to_defined = cpp_warn_expansion_to_defined;
>> + if (cpp_warn_expansion_to_defined == -1)
>> + cpp_warn_expansion_to_defined = pedantic || extra_warnings;
>> +
>
> Instead of the above, plase use LangEnabledBy() or EnabledBy() in c.opt.
> See Wendif-labels and other examples. Then, you do not need Init(-1).
This causes this to produce an error if -pedantic-errors is provided,
because -pedantic-errors does
control_warning_option (OPT_Wpedantic, DK_ERROR, NULL, value,
loc, lang_mask,
handlers, opts, opts_set,
dc);
and this enables -Wexpansion-to-defined at DK_ERROR level. Bug or fix?
Paolo
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] cpp/c: Add -Wexpansion-to-defined
2016-08-09 18:44 ` Eric Gallager
@ 2016-08-09 21:35 ` Paolo Bonzini
0 siblings, 0 replies; 7+ messages in thread
From: Paolo Bonzini @ 2016-08-09 21:35 UTC (permalink / raw)
To: Eric Gallager; +Cc: gcc-patches
On 09/08/2016 20:44, Eric Gallager wrote:
> Hi, I'm just a lurker, but...
>
> On 8/9/16, Paolo Bonzini <bonzini@gnu.org> wrote:
>> Index: gcc/c-family/c.opt
>> ===================================================================
>> --- gcc/c-family/c.opt (revision 239276)
>> +++ gcc/c-family/c.opt (working copy)
>> @@ -506,6 +506,10 @@ Wdouble-promotion
>> C ObjC C++ ObjC++ Var(warn_double_promotion) Warning
>> Warn about implicit conversions from \"float\" to \"double\".
>>
>> +Wexpansion-to-defined
>> +C ObjC C++ ObjC++ CppReason(CPP_W_EXPANSION_TO_DEFINED)
>> Var(cpp_warn_expansion_to_defined) Init(-1) Warning
>> +Warn if an undefined macro is used in an #if directive.
>> +
>
> Isn't "Warn if an undefined macro is used in an #if directive" the
> same description that -Wundef uses in c.opt? Did you copy and paste
> and forget to update that part?
Yes, of course. Thanks!
Paolo
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] cpp/c: Add -Wexpansion-to-defined
2016-08-09 21:21 ` Paolo Bonzini
@ 2016-08-10 0:49 ` Manuel López-Ibáñez
2016-08-10 8:45 ` Paolo Bonzini
0 siblings, 1 reply; 7+ messages in thread
From: Manuel López-Ibáñez @ 2016-08-10 0:49 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: GCC Patches
On 9 August 2016 at 22:21, Paolo Bonzini <bonzini@gnu.org> wrote:
>
>
> On 09/08/2016 20:30, Manuel López-Ibáñez wrote:
>>>
>>>
>>> + cpp_opts->warn_expansion_to_defined = cpp_warn_expansion_to_defined;
>>> + if (cpp_warn_expansion_to_defined == -1)
>>> + cpp_warn_expansion_to_defined = pedantic || extra_warnings;
>>> +
>>
>> Instead of the above, plase use LangEnabledBy() or EnabledBy() in c.opt.
>> See Wendif-labels and other examples. Then, you do not need Init(-1).
>
> This causes this to produce an error if -pedantic-errors is provided,
> because -pedantic-errors does
>
> control_warning_option (OPT_Wpedantic, DK_ERROR, NULL, value,
> loc, lang_mask,
> handlers, opts, opts_set,
> dc);
>
> and this enables -Wexpansion-to-defined at DK_ERROR level. Bug or fix?
TL;DR If the warning is enabled by -Wpedantic, it should be an error
with -Werror=pedantic and it should use cpp_pedwarning. Whether it
should be enabled by -Wpedantic is more difficult to say.
-pedantic is equivalent to -Wpedantic. If -Wx is enabled by -Wy, then
-Werror=y implies -Werror=x. Every warning enabled by -Wpedantic works
in the same way and I don't see why this one should be different.
Moreover, I think that this was a latent bug in libcpp: the code
should have used cpp_pedwarning instead of cpp_warning. This is
https://gcc.gnu.org/PR66505
Quoting https://gcc.gnu.org/wiki/DiagnosticsGuidelines#Types_of_diagnostics
: "The same rules apply to libcpp, which uses cpp_pedwarning (instead
of pedwarn), CPP_PEDANTIC (pfile) (instead of pedantic) and
CPP_W_PEDANTIC (instead of OPT_Wpedantic). In particular, you may use
cpp_pedwarning without CPP_W_PEDANTIC, but you may not use
CPP_W_PEDANTIC without cpp_pedwarning and you may not use CPP_PEDANTIC
(pfile) without CPP_W_PEDANTIC."
Cheers,
Manuel.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] cpp/c: Add -Wexpansion-to-defined
2016-08-10 0:49 ` Manuel López-Ibáñez
@ 2016-08-10 8:45 ` Paolo Bonzini
0 siblings, 0 replies; 7+ messages in thread
From: Paolo Bonzini @ 2016-08-10 8:45 UTC (permalink / raw)
To: Manuel López-Ibáñez; +Cc: GCC Patches
On 10/08/2016 02:48, Manuel López-Ibáñez wrote:
> TL;DR If the warning is enabled by -Wpedantic, it should be an error
> with -Werror=pedantic and it should use cpp_pedwarning. Whether it
> should be enabled by -Wpedantic is more difficult to say.
>
> -pedantic is equivalent to -Wpedantic. If -Wx is enabled by -Wy, then
> -Werror=y implies -Werror=x. Every warning enabled by -Wpedantic works
> in the same way and I don't see why this one should be different.
>
> Moreover, I think that this was a latent bug in libcpp: the code
> should have used cpp_pedwarning instead of cpp_warning. This is
> https://gcc.gnu.org/PR66505
> Quoting https://gcc.gnu.org/wiki/DiagnosticsGuidelines#Types_of_diagnostics
> : "The same rules apply to libcpp, which uses cpp_pedwarning (instead
> of pedwarn), CPP_PEDANTIC (pfile) (instead of pedantic) and
> CPP_W_PEDANTIC (instead of OPT_Wpedantic). In particular, you may use
> cpp_pedwarning without CPP_W_PEDANTIC, but you may not use
> CPP_W_PEDANTIC without cpp_pedwarning and you may not use CPP_PEDANTIC
> (pfile) without CPP_W_PEDANTIC."
But pedwarns are for errors mandated by the standard; this one is not.
Let's just move it from -Wpedantic to -Wextra.
Paolo
^ permalink raw reply [flat|nested] 7+ messages in thread
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Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-09 16:00 [PATCH] cpp/c: Add -Wexpansion-to-defined Paolo Bonzini
2016-08-09 18:30 ` Manuel López-Ibáñez
2016-08-09 21:21 ` Paolo Bonzini
2016-08-10 0:49 ` Manuel López-Ibáñez
2016-08-10 8:45 ` Paolo Bonzini
2016-08-09 18:44 ` Eric Gallager
2016-08-09 21:35 ` Paolo Bonzini
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