On Fri, Dec 30, 2011 at 10:38:03AM +0100, Jakub Jelinek wrote:
> On Thu, Dec 29, 2011 at 08:12:51PM -0800, Steve Kargl wrote:
> > The audit trail in the PR pretty much sums up the problem.
> > OK to commit?
>
> Can you tune up the comments a little bit?
> If you look up http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
> you'll see that most of the C++11 features are already implemented
> (and e.g. at_quick_exit is implemented too in some libcs), so the
> __cplusplus macro isn't lying. Clang apparently defines __cplusplus
> to 201103L much longer than GCC does, yet it supports much smaller subset
> of C++11. Apparently it parses the C++11 generalized attribute syntax,
> but at least clang 3.0 doesn't complain at all about anything between
> the [[ and ]] pair, [[foobar, foobaz (bar, baz, 2, 6, 0x1z2)]] void bar
> (void);
> is parsed just fine, and with [[noreturn]] it miscompiles even the first
> [[noreturn]] trivial testcase I wrote.
> See
> http://gcc.gnu.org/ml/gcc-patches/2011-10/msg02027.html
> for why we set __cplusplus to the value we do.
I'm sorry, but I find "clang did this, so g++ better follow
suit" to be a rather uncompelling technical reason for
defining __cplusplus to be 201103L [1]. The technical question
is fairly simple: "Does g++ conform to the C++11 standard?"
>From my cursory scanning of n3242.pdf, the answer is obviously
'no' given that [[noreturn]] appears to be neither a
conditionally-supported feature nor implementation-defined
behavior. So, we now look at what n3242.pdf says about
__cplusplus:
Sec. 16.8 (p. 415)
__cplusplus
The name __cplusplus is defined to the value 201103L when compiling
a C++ translation unit. [155]
155) It is intended that future versions of this standard will replace
the value of this macro with a greater value. Non-conforming compilers
should use a value with at most five decimal digits.
201103 is 6 digits!
Again, a cursory scan of n3242.pdf does not reveal whether a footnote
is normative or non-normative text. So, footnote [155] may simply
be a suggestion rather than a requirement.
[1] Interestly, in a 1334 page document, n3242.pdf does not state
how one is to interpret __cplusplus nor its value.
So, once again OK for trunk?
2011-12-29 Steven G. Kargl <[email protected]>
* inclhack.def: 'g++ -std=c++11' defines __cplusplus to 201103L,
which suggests that 'g++ -std=c++11' is a compiler conforming
to the C++ programming language defined by ISO/IEC 14882:2011.
Setting __cplusplus to 201103L appears to be a direct violation
of ISO/IEC 14882:2011. The standard conforming sys/cdefs.h
header file on FreeBSD 10 (and above) needs be (un)damaged, so
GCC can use 'g++ -std=c++11' to build libstdc++v3 during bootstrap.
* fixincl.x: Regenerated.
* genfixes: Fix to version test.
--
Steve
Index: inclhack.def
===================================================================
--- inclhack.def (revision 182738)
+++ inclhack.def (working copy)
@@ -20,6 +20,27 @@ autogen definitions fixincl;
FIXINC_DEBUG = yes;
#endif
+/*
+ * 'g++ -std=c++11' defines __cplusplus to 201103L, which suggests
+ * that 'g++ -std=c++11' is a compiler conforming to the C++ programming
+ * language defined by ISO/IEC 14882:2011. Setting __cplusplus to
+ * 201103L appears to be a direct violation of ISO/IEC 14882:2011
+ * [as inferred from Secs. 1.4 and 16.8 in n3242.pdf (I'm not interested
+ * in spending CHF 352.00 for the actual standard)]. The standard
+ * conforming sys/cdefs.h header file on FreeBSD 10 (and above) needs be
+ * (un)damaged, so GCC can use 'g++ -std=c++11' to build libstdc++v3
+ * during bootstrap.
+ */
+fix = {
+ hackname = cdef_cplusplus;
+ mach = "*-*-freebsd10.*";
+ files = sys/cdefs.h;
+ select = "\\[\\[noreturn\\]\\]";
+ sed = "s/\\[\\[noreturn\\]\\]/__attribute__\(\(__noreturn__\)\)/";
+ test_text = "#include <sys/cdefs.h>";
+};
+
+
/* On AIX when _LARGE_FILES is defined stdio.h defines fopen to
* fopen64 etc. and this causes problems when building with g++
* because cstdio udefs everything from stdio.h, leaving us with
Index: fixincl.x
===================================================================
--- fixincl.x (revision 182738)
+++ fixincl.x (working copy)
@@ -2,11 +2,11 @@
*
* DO NOT EDIT THIS FILE (fixincl.x)
*
- * It has been AutoGen-ed November 7, 2011 at 01:16:39 PM by AutoGen 5.10
+ * It has been AutoGen-ed December 30, 2011 at 11:21:34 AM by AutoGen 5.12
* From the definitions inclhack.def
* and the template file fixincl
*/
-/* DO NOT SVN-MERGE THIS FILE, EITHER Mon Nov 7 13:16:39 EST 2011
+/* DO NOT SVN-MERGE THIS FILE, EITHER Fri Dec 30 11:21:34 PST 2011
*
* You must regenerate it. Use the ./genfixes script.
*
@@ -15,7 +15,7 @@
* certain ANSI-incompatible system header files which are fixed to work
* correctly with ANSI C and placed in a directory that GNU C will search.
*
- * This file contains 222 fixup descriptions.
+ * This file contains 223 fixup descriptions.
*
* See README for more information.
*
@@ -43,6 +43,42 @@ static char const sed_cmd_z[] = SED_PROG
/* * * * * * * * * * * * * * * * * * * * * * * * * *
*
+ * Description of Cdef_Cplusplus fix
+ */
+tSCC zCdef_CplusplusName[] =
+ "cdef_cplusplus";
+
+/*
+ * File name selection pattern
+ */
+tSCC zCdef_CplusplusList[] =
+ "sys/cdefs.h\0";
+/*
+ * Machine/OS name selection pattern
+ */
+tSCC* apzCdef_CplusplusMachs[] = {
+ "*-*-freebsd10.*",
+ (const char*)NULL };
+
+/*
+ * content selection pattern - do fix if pattern found
+ */
+tSCC zCdef_CplusplusSelect0[] =
+ "\\[\\[noreturn\\]\\]";
+
+#define CDEF_CPLUSPLUS_TEST_CT 1
+static tTestDesc aCdef_CplusplusTests[] = {
+ { TT_EGREP, zCdef_CplusplusSelect0, (regex_t*)NULL }, };
+
+/*
+ * Fix Command Arguments for Cdef_Cplusplus
+ */
+static const char* apzCdef_CplusplusPatch[] = { sed_cmd_z,
+ "-e", "s/\\[\\[noreturn\\]\\]/__attribute__((__noreturn__))/",
+ (char*)NULL };
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * *
+ *
* Description of Aab_Aix_Stdio fix
*/
tSCC zAab_Aix_StdioName[] =
@@ -9034,14 +9070,15 @@ static const char* apzX11_SprintfPatch[]
*
* List of all fixes
*/
-#define REGEX_COUNT 264
+#define REGEX_COUNT 265
#define MACH_LIST_SIZE_LIMIT 181
-#define FIX_COUNT 222
+#define FIX_COUNT 223
/*
* Enumerate the fixes
*/
typedef enum {
+ CDEF_CPLUSPLUS_FIXIDX,
AAB_AIX_STDIO_FIXIDX,
AAB_DARWIN7_9_LONG_DOUBLE_FUNCS_FIXIDX,
AAB_DARWIN7_9_LONG_DOUBLE_FUNCS_2_FIXIDX,
@@ -9267,6 +9304,11 @@ typedef enum {
} t_fixinc_idx;
tFixDesc fixDescList[ FIX_COUNT ] = {
+ { zCdef_CplusplusName, zCdef_CplusplusList,
+ apzCdef_CplusplusMachs,
+ CDEF_CPLUSPLUS_TEST_CT, FD_MACH_ONLY,
+ aCdef_CplusplusTests, apzCdef_CplusplusPatch, 0 },
+
{ zAab_Aix_StdioName, zAab_Aix_StdioList,
apzAab_Aix_StdioMachs,
AAB_AIX_STDIO_TEST_CT, FD_MACH_ONLY | FD_SUBROUTINE,
Index: genfixes
===================================================================
--- genfixes (revision 182738)
+++ genfixes (working copy)
@@ -62,7 +62,7 @@ fi
AG="autogen $AG"
set -e
-if [ -z "`${AG} -v | fgrep 'Ver. 5.'`" ]
+if [ -z "`${AG} -v | fgrep '5.'`" ]
then
echo "AutoGen appears to be out of date or not correctly installed."
echo "Please download and install:"
