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bpo-11410: Standardize and use symbol visibility attributes across POSIX and Windows. (GH-16347)
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12 files changed

+132
-35
lines changed

12 files changed

+132
-35
lines changed

‎Include/exports.h

Lines changed: 30 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,30 @@
1+
#ifndef Py_EXPORTS_H
2+
#define Py_EXPORTS_H
3+
4+
#if defined(_WIN32) || defined(__CYGWIN__)
5+
#define Py_IMPORTED_SYMBOL __declspec(dllimport)
6+
#define Py_EXPORTED_SYMBOL __declspec(dllexport)
7+
#define Py_LOCAL_SYMBOL
8+
#else
9+
/*
10+
* If we only ever used gcc >= 5, we could use __has_attribute(visibility)
11+
* as a cross-platform way to determine if visibility is supported. However,
12+
* we may still need to support gcc >= 4, as some Ubuntu LTS and Centos versions
13+
* have 4 < gcc < 5.
14+
*/
15+
#ifndef __has_attribute
16+
#define __has_attribute(x) 0 // Compatibility with non-clang compilers.
17+
#endif
18+
#if (defined(__GNUC__) && (__GNUC__ >= 4)) ||\
19+
(defined(__clang__) && __has_attribute(visibility))
20+
#define Py_IMPORTED_SYMBOL __attribute__ ((visibility ("default")))
21+
#define Py_EXPORTED_SYMBOL __attribute__ ((visibility ("default")))
22+
#define Py_LOCAL_SYMBOL __attribute__ ((visibility ("hidden")))
23+
#else
24+
#define Py_IMPORTED_SYMBOL
25+
#define Py_EXPORTED_SYMBOL
26+
#define Py_LOCAL_SYMBOL
27+
#endif
28+
#endif
29+
30+
#endif /* Py_EXPORTS_H */

‎Include/pyport.h

Lines changed: 13 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -638,16 +638,18 @@ extern char * _getpty(int *, int, mode_t, int);
638638
# define HAVE_DECLSPEC_DLL
639639
#endif
640640

641+
#include "exports.h"
642+
641643
/* only get special linkage if built as shared or platform is Cygwin */
642644
#if defined(Py_ENABLE_SHARED) || defined(__CYGWIN__)
643645
# if defined(HAVE_DECLSPEC_DLL)
644646
# if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
645-
# define PyAPI_FUNC(RTYPE) __declspec(dllexport) RTYPE
646-
# define PyAPI_DATA(RTYPE) extern __declspec(dllexport) RTYPE
647+
# define PyAPI_FUNC(RTYPE) Py_EXPORTED_SYMBOL RTYPE
648+
# define PyAPI_DATA(RTYPE) extern Py_EXPORTED_SYMBOL RTYPE
647649
/* module init functions inside the core need no external linkage */
648650
/* except for Cygwin to handle embedding */
649651
# if defined(__CYGWIN__)
650-
# define PyMODINIT_FUNC __declspec(dllexport) PyObject*
652+
# define PyMODINIT_FUNC Py_EXPORTED_SYMBOL PyObject*
651653
# else /* __CYGWIN__ */
652654
# define PyMODINIT_FUNC PyObject*
653655
# endif /* __CYGWIN__ */
@@ -658,31 +660,31 @@ extern char * _getpty(int *, int, mode_t, int);
658660
/* failures similar to those described at the bottom of 4.1: */
659661
/* http://docs.python.org/extending/windows.html#a-cookbook-approach */
660662
# if !defined(__CYGWIN__)
661-
# define PyAPI_FUNC(RTYPE) __declspec(dllimport) RTYPE
663+
# define PyAPI_FUNC(RTYPE) Py_IMPORTED_SYMBOL RTYPE
662664
# endif /* !__CYGWIN__ */
663-
# define PyAPI_DATA(RTYPE) extern __declspec(dllimport) RTYPE
665+
# define PyAPI_DATA(RTYPE) extern Py_IMPORTED_SYMBOL RTYPE
664666
/* module init functions outside the core must be exported */
665667
# if defined(__cplusplus)
666-
# define PyMODINIT_FUNC extern "C" __declspec(dllexport) PyObject*
668+
# define PyMODINIT_FUNC extern "C" Py_EXPORTED_SYMBOL PyObject*
667669
# else /* __cplusplus */
668-
# define PyMODINIT_FUNC __declspec(dllexport) PyObject*
670+
# define PyMODINIT_FUNC Py_EXPORTED_SYMBOL PyObject*
669671
# endif /* __cplusplus */
670672
# endif /* Py_BUILD_CORE */
671673
# endif /* HAVE_DECLSPEC_DLL */
672674
#endif /* Py_ENABLE_SHARED */
673675

674676
/* If no external linkage macros defined by now, create defaults */
675677
#ifndef PyAPI_FUNC
676-
# define PyAPI_FUNC(RTYPE) RTYPE
678+
# define PyAPI_FUNC(RTYPE) Py_EXPORTED_SYMBOL RTYPE
677679
#endif
678680
#ifndef PyAPI_DATA
679-
# define PyAPI_DATA(RTYPE) extern RTYPE
681+
# define PyAPI_DATA(RTYPE) extern Py_EXPORTED_SYMBOL RTYPE
680682
#endif
681683
#ifndef PyMODINIT_FUNC
682684
# if defined(__cplusplus)
683-
# define PyMODINIT_FUNC extern "C" PyObject*
685+
# define PyMODINIT_FUNC extern "C" Py_EXPORTED_SYMBOL PyObject*
684686
# else /* __cplusplus */
685-
# define PyMODINIT_FUNC PyObject*
687+
# define PyMODINIT_FUNC Py_EXPORTED_SYMBOL PyObject*
686688
# endif /* __cplusplus */
687689
#endif
688690

‎Misc/NEWS.d/next/Core and Builtins/2019-09-24-05-32-27.bpo-11410.vS182p.rst

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,4 @@
1+
Better control over symbol visibility is provided through use of the
2+
visibility attributes available in gcc >= 4.0, provided in a uniform way
3+
across POSIX and Windows. The POSIX build files have been updated to compile
4+
with -fvisibility=hidden, minimising exported symbols.

‎Modules/_ctypes/_ctypes_test.c

Lines changed: 1 addition & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -4,11 +4,7 @@
44
#include <windows.h>
55
#endif
66

7-
#if defined(MS_WIN32) || defined(__CYGWIN__)
8-
#define EXPORT(x) __declspec(dllexport) x
9-
#else
10-
#define EXPORT(x) x
11-
#endif
7+
#define EXPORT(x) Py_EXPORTED_SYMBOL x
128

139
/* some functions handy for testing */
1410

‎Modules/_io/_iomodule.h

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,8 @@
22
* Declarations shared between the different parts of the io module
33
*/
44

5+
#include "exports.h"
6+
57
/* ABCs */
68
extern PyTypeObject PyIOBase_Type;
79
extern PyTypeObject PyRawIOBase_Type;
@@ -183,4 +185,4 @@ extern PyObject *_PyIO_str_write;
183185
extern PyObject *_PyIO_empty_str;
184186
extern PyObject *_PyIO_empty_bytes;
185187

186-
extern PyTypeObject _PyBytesIOBuffer_Type;
188+
extern Py_EXPORTED_SYMBOL PyTypeObject _PyBytesIOBuffer_Type;

‎Modules/_io/bytesio.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1124,7 +1124,7 @@ static PyBufferProcs bytesiobuf_as_buffer = {
11241124
(releasebufferproc) bytesiobuf_releasebuffer,
11251125
};
11261126

1127-
PyTypeObject _PyBytesIOBuffer_Type = {
1127+
Py_EXPORTED_SYMBOL PyTypeObject _PyBytesIOBuffer_Type = {
11281128
PyVarObject_HEAD_INIT(NULL, 0)
11291129
"_io._BytesIOBuffer", /*tp_name*/
11301130
sizeof(bytesiobuf), /*tp_basicsize*/

‎Parser/pgen/grammar.py

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -61,13 +61,14 @@ def produce_graminit_h(self, writer):
6161
def produce_graminit_c(self, writer):
6262
writer("/* Generated by Parser/pgen */\n\n")
6363

64+
writer('#include "exports.h"\n')
6465
writer('#include "grammar.h"\n')
65-
writer("grammar _PyParser_Grammar;\n")
66+
writer("Py_EXPORTED_SYMBOL grammar _PyParser_Grammar;\n")
6667

6768
self.print_dfas(writer)
6869
self.print_labels(writer)
6970

70-
writer("grammar _PyParser_Grammar = {\n")
71+
writer("Py_EXPORTED_SYMBOL grammar _PyParser_Grammar = {\n")
7172
writer(" {n_dfas},\n".format(n_dfas=len(self.dfas)))
7273
writer(" dfas,\n")
7374
writer(" {{{n_labels}, labels}},\n".format(n_labels=len(self.labels)))

‎Python/getargs.c

Lines changed: 12 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -106,7 +106,7 @@ PyArg_Parse(PyObject *args, const char *format, ...)
106106
return retval;
107107
}
108108

109-
int
109+
PyAPI_FUNC(int)
110110
_PyArg_Parse_SizeT(PyObject *args, const char *format, ...)
111111
{
112112
int retval;
@@ -131,7 +131,7 @@ PyArg_ParseTuple(PyObject *args, const char *format, ...)
131131
return retval;
132132
}
133133

134-
int
134+
PyAPI_FUNC(int)
135135
_PyArg_ParseTuple_SizeT(PyObject *args, const char *format, ...)
136136
{
137137
int retval;
@@ -156,7 +156,7 @@ _PyArg_ParseStack(PyObject *const *args, Py_ssize_t nargs, const char *format, .
156156
return retval;
157157
}
158158

159-
int
159+
PyAPI_FUNC(int)
160160
_PyArg_ParseStack_SizeT(PyObject *const *args, Py_ssize_t nargs, const char *format, ...)
161161
{
162162
int retval;
@@ -182,7 +182,7 @@ PyArg_VaParse(PyObject *args, const char *format, va_list va)
182182
return retval;
183183
}
184184

185-
int
185+
PyAPI_FUNC(int)
186186
_PyArg_VaParse_SizeT(PyObject *args, const char *format, va_list va)
187187
{
188188
va_list lva;
@@ -1442,7 +1442,7 @@ PyArg_ParseTupleAndKeywords(PyObject *args,
14421442
return retval;
14431443
}
14441444

1445-
int
1445+
PyAPI_FUNC(int)
14461446
_PyArg_ParseTupleAndKeywords_SizeT(PyObject *args,
14471447
PyObject *keywords,
14481448
const char *format,
@@ -1493,7 +1493,7 @@ PyArg_VaParseTupleAndKeywords(PyObject *args,
14931493
return retval;
14941494
}
14951495

1496-
int
1496+
PyAPI_FUNC(int)
14971497
_PyArg_VaParseTupleAndKeywords_SizeT(PyObject *args,
14981498
PyObject *keywords,
14991499
const char *format,
@@ -1519,7 +1519,7 @@ _PyArg_VaParseTupleAndKeywords_SizeT(PyObject *args,
15191519
return retval;
15201520
}
15211521

1522-
int
1522+
PyAPI_FUNC(int)
15231523
_PyArg_ParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
15241524
struct _PyArg_Parser *parser, ...)
15251525
{
@@ -1532,7 +1532,7 @@ _PyArg_ParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
15321532
return retval;
15331533
}
15341534

1535-
int
1535+
PyAPI_FUNC(int)
15361536
_PyArg_ParseTupleAndKeywordsFast_SizeT(PyObject *args, PyObject *keywords,
15371537
struct _PyArg_Parser *parser, ...)
15381538
{
@@ -1545,7 +1545,7 @@ _PyArg_ParseTupleAndKeywordsFast_SizeT(PyObject *args, PyObject *keywords,
15451545
return retval;
15461546
}
15471547

1548-
int
1548+
PyAPI_FUNC(int)
15491549
_PyArg_ParseStackAndKeywords(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
15501550
struct _PyArg_Parser *parser, ...)
15511551
{
@@ -1558,7 +1558,7 @@ _PyArg_ParseStackAndKeywords(PyObject *const *args, Py_ssize_t nargs, PyObject *
15581558
return retval;
15591559
}
15601560

1561-
int
1561+
PyAPI_FUNC(int)
15621562
_PyArg_ParseStackAndKeywords_SizeT(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
15631563
struct _PyArg_Parser *parser, ...)
15641564
{
@@ -1572,7 +1572,7 @@ _PyArg_ParseStackAndKeywords_SizeT(PyObject *const *args, Py_ssize_t nargs, PyOb
15721572
}
15731573

15741574

1575-
int
1575+
PyAPI_FUNC(int)
15761576
_PyArg_VaParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
15771577
struct _PyArg_Parser *parser, va_list va)
15781578
{
@@ -1586,7 +1586,7 @@ _PyArg_VaParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
15861586
return retval;
15871587
}
15881588

1589-
int
1589+
PyAPI_FUNC(int)
15901590
_PyArg_VaParseTupleAndKeywordsFast_SizeT(PyObject *args, PyObject *keywords,
15911591
struct _PyArg_Parser *parser, va_list va)
15921592
{

‎Python/graminit.c

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,8 @@
11
/* Generated by Parser/pgen */
22

3+
#include "exports.h"
34
#include "grammar.h"
4-
grammar _PyParser_Grammar;
5+
Py_EXPORTED_SYMBOL grammar _PyParser_Grammar;
56
static const arc arcs_0_0[3] = {
67
{2, 1},
78
{3, 2},
@@ -2693,7 +2694,7 @@ static const label labels[183] = {
26932694
{346, 0},
26942695
{347, 0},
26952696
};
2696-
grammar _PyParser_Grammar = {
2697+
Py_EXPORTED_SYMBOL grammar _PyParser_Grammar = {
26972698
92,
26982699
dfas,
26992700
{183, labels},

‎Python/pythonrun.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -57,7 +57,7 @@ _Py_static_string(PyId_string, "<string>");
5757
extern "C" {
5858
#endif
5959

60-
extern grammar _PyParser_Grammar; /* From graminit.c */
60+
extern Py_EXPORTED_SYMBOL grammar _PyParser_Grammar; /* From graminit.c */
6161

6262
/* Forward */
6363
static void flush_io(void);

‎configure

Lines changed: 41 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -7341,6 +7341,47 @@ $as_echo "$ac_cv_enable_implicit_function_declaration_error" >&6; }
73417341
CFLAGS_NODIST="$CFLAGS_NODIST -Werror=implicit-function-declaration"
73427342
fi
73437343

7344+
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if we can use visibility in $CC" >&5
7345+
$as_echo_n "checking if we can use visibility in $CC... " >&6; }
7346+
ac_save_cc="$CC"
7347+
CC="$CC -fvisibility=hidden"
7348+
if ${ac_cv_enable_visibility+:} false; then :
7349+
$as_echo_n "(cached) " >&6
7350+
else
7351+
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
7352+
/* end confdefs.h. */
7353+
7354+
7355+
int
7356+
main ()
7357+
{
7358+
7359+
;
7360+
return 0;
7361+
}
7362+
7363+
_ACEOF
7364+
if ac_fn_c_try_compile "$LINENO"; then :
7365+
7366+
ac_cv_enable_visibility=yes
7367+
7368+
else
7369+
7370+
ac_cv_enable_visibility=no
7371+
7372+
fi
7373+
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
7374+
fi
7375+
7376+
CC="$ac_save_cc"
7377+
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_enable_visibility" >&5
7378+
$as_echo "$ac_cv_enable_visibility" >&6; }
7379+
7380+
if test $ac_cv_enable_visibility = yes
7381+
then
7382+
CFLAGS_NODIST="$CFLAGS_NODIST -fvisibility=hidden"
7383+
fi
7384+
73447385
# if using gcc on alpha, use -mieee to get (near) full IEEE 754
73457386
# support. Without this, treatment of subnormals doesn't follow
73467387
# the standard.

‎configure.ac

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1787,6 +1787,26 @@ yes)
17871787
CFLAGS_NODIST="$CFLAGS_NODIST -Werror=implicit-function-declaration"
17881788
fi
17891789

1790+
AC_MSG_CHECKING(if we can use visibility in $CC)
1791+
ac_save_cc="$CC"
1792+
CC="$CC -fvisibility=hidden"
1793+
AC_CACHE_VAL(ac_cv_enable_visibility,
1794+
AC_COMPILE_IFELSE(
1795+
[
1796+
AC_LANG_PROGRAM([[]], [[]])
1797+
],[
1798+
ac_cv_enable_visibility=yes
1799+
],[
1800+
ac_cv_enable_visibility=no
1801+
]))
1802+
CC="$ac_save_cc"
1803+
AC_MSG_RESULT($ac_cv_enable_visibility)
1804+
1805+
if test $ac_cv_enable_visibility = yes
1806+
then
1807+
CFLAGS_NODIST="$CFLAGS_NODIST -fvisibility=hidden"
1808+
fi
1809+
17901810
# if using gcc on alpha, use -mieee to get (near) full IEEE 754
17911811
# support. Without this, treatment of subnormals doesn't follow
17921812
# the standard.

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