1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
https://github.com/python/cpython/commit/9ba3aa4d02a110d1a1ea464a8aff3be7dd9c63c3.patch
From 9ba3aa4d02a110d1a1ea464a8aff3be7dd9c63c3 Mon Sep 17 00:00:00 2001
From: Erik Bray <erik.m.bray@gmail.com>
Date: Wed, 7 Jun 2017 18:42:24 +0100
Subject: [PATCH] bpo-30353: Fix pass by value for structs on 64-bit
Cygwin/MinGW (GH-1559)
---
Lib/ctypes/test/test_as_parameter.py | 4 ++++
Lib/ctypes/test/test_structures.py | 22 ++++++++++++++++++++++
Modules/_ctypes/_ctypes_test.c | 18 ++++++++++++++++++
Modules/_ctypes/callproc.c | 23 +++++++++++++++++++++--
4 files changed, 65 insertions(+), 2 deletions(-)
diff --git a/Lib/ctypes/test/test_as_parameter.py b/Lib/ctypes/test/test_as_parameter.py
index 2a3484bec01..a2640575a07 100644
--- a/Lib/ctypes/test/test_as_parameter.py
+++ b/Lib/ctypes/test/test_as_parameter.py
@@ -169,6 +169,10 @@ class S2H(Structure):
s2h = dll.ret_2h_func(self.wrap(inp))
self.assertEqual((s2h.x, s2h.y), (99*2, 88*3))
+ # Test also that the original struct was unmodified (i.e. was passed by
+ # value)
+ self.assertEqual((inp.x, inp.y), (99, 88))
+
def test_struct_return_8H(self):
class S8I(Structure):
_fields_ = [("a", c_int),
diff --git a/Lib/ctypes/test/test_structures.py b/Lib/ctypes/test/test_structures.py
index 2e778fb1b43..d90c71144c9 100644
--- a/Lib/ctypes/test/test_structures.py
+++ b/Lib/ctypes/test/test_structures.py
@@ -417,6 +417,28 @@ class X(Structure):
self.assertEqual(s.second, 0xcafebabe)
self.assertEqual(s.third, 0x0bad1dea)
+ def test_pass_by_value_in_register(self):
+ class X(Structure):
+ _fields_ = [
+ ('first', c_uint),
+ ('second', c_uint)
+ ]
+
+ s = X()
+ s.first = 0xdeadbeef
+ s.second = 0xcafebabe
+ dll = CDLL(_ctypes_test.__file__)
+ func = dll._testfunc_reg_struct_update_value
+ func.argtypes = (X,)
+ func.restype = None
+ func(s)
+ self.assertEqual(s.first, 0xdeadbeef)
+ self.assertEqual(s.second, 0xcafebabe)
+ got = X.in_dll(dll, "last_tfrsuv_arg")
+ self.assertEqual(s.first, got.first)
+ self.assertEqual(s.second, got.second)
+
+
class PointerMemberTestCase(unittest.TestCase):
def test(self):
diff --git a/Modules/_ctypes/_ctypes_test.c b/Modules/_ctypes/_ctypes_test.c
index fe0015c8013..2255e573393 100644
--- a/Modules/_ctypes/_ctypes_test.c
+++ b/Modules/_ctypes/_ctypes_test.c
@@ -57,6 +57,24 @@ _testfunc_large_struct_update_value(Test in)
((volatile Test *)&in)->third = 0x0badf00d;
}
+typedef struct {
+ unsigned int first;
+ unsigned int second;
+} TestReg;
+
+
+EXPORT(TestReg) last_tfrsuv_arg;
+
+
+EXPORT(void)
+_testfunc_reg_struct_update_value(TestReg in)
+{
+ last_tfrsuv_arg = in;
+ ((volatile TestReg *)&in)->first = 0x0badf00d;
+ ((volatile TestReg *)&in)->second = 0x0badf00d;
+}
+
+
EXPORT(void)testfunc_array(int values[4])
{
printf("testfunc_array %d %d %d %d\n",
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 0b6faf96c68..5439b939dc4 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -1039,6 +1039,13 @@ GetComError(HRESULT errcode, GUID *riid, IUnknown *pIunk)
}
#endif
+#if (defined(__x86_64__) && (defined(__MINGW64__) || defined(__CYGWIN__))) || \
+ defined(__aarch64__)
+#define CTYPES_PASS_BY_REF_HACK
+#define POW2(x) (((x & ~(x - 1)) == x) ? x : 0)
+#define IS_PASS_BY_REF(x) (x > 8 || !POW2(x))
+#endif
+
/*
* Requirements, must be ensured by the caller:
* - argtuple is tuple of arguments
@@ -1136,8 +1143,20 @@ PyObject *_ctypes_callproc(PPROC pProc,
}
for (i = 0; i < argcount; ++i) {
atypes[i] = args[i].ffi_type;
- if (atypes[i]->type == FFI_TYPE_STRUCT
- )
+#ifdef CTYPES_PASS_BY_REF_HACK
+ size_t size = atypes[i]->size;
+ if (IS_PASS_BY_REF(size)) {
+ void *tmp = alloca(size);
+ if (atypes[i]->type == FFI_TYPE_STRUCT)
+ memcpy(tmp, args[i].value.p, size);
+ else
+ memcpy(tmp, (void*)&args[i].value, size);
+
+ avalues[i] = tmp;
+ }
+ else
+#endif
+ if (atypes[i]->type == FFI_TYPE_STRUCT)
avalues[i] = (void *)args[i].value.p;
else
avalues[i] = (void *)&args[i].value;
|
