[Python-checkins] [2.7] bpo-34603, ctypes/libffi_msvc: Fix returning structs from functions (GH-9258) (GH-9425)
Victor Stinner
webhook-mailer at python.org
Wed Sep 19 16:48:26 EDT 2018
https://github.com/python/cpython/commit/b63a16febbd1c943c9dbc5c651326b410aa50698
commit: b63a16febbd1c943c9dbc5c651326b410aa50698
branch: 2.7
author: Vladimir Matveev <v2matveev at outlook.com>
committer: Victor Stinner <vstinner at redhat.com>
date: 2018-09-19T13:48:21-07:00
summary:
[2.7] bpo-34603, ctypes/libffi_msvc: Fix returning structs from functions (GH-9258) (GH-9425)
Co-authored-by: Vladimir Matveev <v2matveev at outlook.com>
files:
A Misc/NEWS.d/next/Windows/2018-09-13-08-29-04.bpo-34603.2AB7sc.rst
M Lib/ctypes/test/test_win32.py
M Modules/_ctypes/_ctypes_test.c
M Modules/_ctypes/callproc.c
M Modules/_ctypes/libffi_msvc/ffi.c
M Modules/_ctypes/libffi_msvc/ffi.h
M Modules/_ctypes/libffi_msvc/prep_cif.c
diff --git a/Lib/ctypes/test/test_win32.py b/Lib/ctypes/test/test_win32.py
index d22e139a3f97..13a986359fa4 100644
--- a/Lib/ctypes/test/test_win32.py
+++ b/Lib/ctypes/test/test_win32.py
@@ -52,6 +52,24 @@ def test_noargs(self):
# This is a special case on win32 x64
windll.user32.GetDesktopWindow()
+ at unittest.skipUnless(sys.platform == "win32", 'Windows-specific test')
+class ReturnStructSizesTestCase(unittest.TestCase):
+ def test_sizes(self):
+ dll = CDLL(_ctypes_test.__file__)
+ for i in range(1, 11):
+ fields = [ ("f%d" % f, c_char) for f in range(1, i + 1)]
+ class S(Structure):
+ _fields_ = fields
+ f = getattr(dll, "TestSize%d" % i)
+ f.restype = S
+ res = f()
+ for i, f in enumerate(fields):
+ value = getattr(res, f[0])
+ expected = chr(ord('a') + i)
+ self.assertEquals(value, expected)
+
+
+
@unittest.skipUnless(sys.platform == "win32", 'Windows-specific test')
class TestWintypes(unittest.TestCase):
def test_HWND(self):
diff --git a/Misc/NEWS.d/next/Windows/2018-09-13-08-29-04.bpo-34603.2AB7sc.rst b/Misc/NEWS.d/next/Windows/2018-09-13-08-29-04.bpo-34603.2AB7sc.rst
new file mode 100644
index 000000000000..86ae1cd06171
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2018-09-13-08-29-04.bpo-34603.2AB7sc.rst
@@ -0,0 +1 @@
+Fix returning structs from functions produced by MSVC
diff --git a/Modules/_ctypes/_ctypes_test.c b/Modules/_ctypes/_ctypes_test.c
index 94678f3189ce..93876d3d01a6 100644
--- a/Modules/_ctypes/_ctypes_test.c
+++ b/Modules/_ctypes/_ctypes_test.c
@@ -655,6 +655,200 @@ EXPORT(void) TwoOutArgs(int a, int *pi, int b, int *pj)
*pj += b;
}
+#ifdef MS_WIN32
+
+typedef struct {
+ char f1;
+} Size1;
+
+typedef struct {
+ char f1;
+ char f2;
+} Size2;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+} Size3;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+ char f4;
+} Size4;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+ char f4;
+ char f5;
+} Size5;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+ char f4;
+ char f5;
+ char f6;
+} Size6;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+ char f4;
+ char f5;
+ char f6;
+ char f7;
+} Size7;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+ char f4;
+ char f5;
+ char f6;
+ char f7;
+ char f8;
+} Size8;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+ char f4;
+ char f5;
+ char f6;
+ char f7;
+ char f8;
+ char f9;
+} Size9;
+
+typedef struct {
+ char f1;
+ char f2;
+ char f3;
+ char f4;
+ char f5;
+ char f6;
+ char f7;
+ char f8;
+ char f9;
+ char f10;
+} Size10;
+
+EXPORT(Size1) TestSize1() {
+ Size1 f;
+ f.f1 = 'a';
+ return f;
+}
+
+EXPORT(Size2) TestSize2() {
+ Size2 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ return f;
+}
+
+EXPORT(Size3) TestSize3() {
+ Size3 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ return f;
+}
+
+EXPORT(Size4) TestSize4() {
+ Size4 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ f.f4 = 'd';
+ return f;
+}
+
+EXPORT(Size5) TestSize5() {
+ Size5 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ f.f4 = 'd';
+ f.f5 = 'e';
+ return f;
+}
+
+EXPORT(Size6) TestSize6() {
+ Size6 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ f.f4 = 'd';
+ f.f5 = 'e';
+ f.f6 = 'f';
+ return f;
+}
+
+EXPORT(Size7) TestSize7() {
+ Size7 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ f.f4 = 'd';
+ f.f5 = 'e';
+ f.f6 = 'f';
+ f.f7 = 'g';
+ return f;
+}
+
+EXPORT(Size8) TestSize8() {
+ Size8 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ f.f4 = 'd';
+ f.f5 = 'e';
+ f.f6 = 'f';
+ f.f7 = 'g';
+ f.f8 = 'h';
+ return f;
+}
+
+EXPORT(Size9) TestSize9() {
+ Size9 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ f.f4 = 'd';
+ f.f5 = 'e';
+ f.f6 = 'f';
+ f.f7 = 'g';
+ f.f8 = 'h';
+ f.f9 = 'i';
+ return f;
+}
+
+EXPORT(Size10) TestSize10() {
+ Size10 f;
+ f.f1 = 'a';
+ f.f2 = 'b';
+ f.f3 = 'c';
+ f.f4 = 'd';
+ f.f5 = 'e';
+ f.f6 = 'f';
+ f.f7 = 'g';
+ f.f8 = 'h';
+ f.f9 = 'i';
+ f.f10 = 'j';
+ return f;
+}
+
+#endif
+
#ifdef MS_WIN32
EXPORT(S2H) __stdcall s_ret_2h_func(S2H inp) { return ret_2h_func(inp); }
EXPORT(S8I) __stdcall s_ret_8i_func(S8I inp) { return ret_8i_func(inp); }
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 91233d508c57..63f3c21784d5 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -747,9 +747,9 @@ ffi_type *_ctypes_get_ffi_type(PyObject *obj)
It returns small structures in registers
*/
if (dict->ffi_type_pointer.type == FFI_TYPE_STRUCT) {
- if (dict->ffi_type_pointer.size <= 4)
+ if (can_return_struct_as_int(dict->ffi_type_pointer.size))
return &ffi_type_sint32;
- else if (dict->ffi_type_pointer.size <= 8)
+ else if (can_return_struct_as_sint64 (dict->ffi_type_pointer.size))
return &ffi_type_sint64;
}
#endif
diff --git a/Modules/_ctypes/libffi_msvc/ffi.c b/Modules/_ctypes/libffi_msvc/ffi.c
index 587c94b7e61f..15a100fe3467 100644
--- a/Modules/_ctypes/libffi_msvc/ffi.c
+++ b/Modules/_ctypes/libffi_msvc/ffi.c
@@ -126,6 +126,21 @@ void ffi_prep_args(char *stack, extended_cif *ecif)
return;
}
+/*
+Per: https://msdn.microsoft.com/en-us/library/7572ztz4.aspx
+To be returned by value in RAX, user-defined types must have a length
+of 1, 2, 4, 8, 16, 32, or 64 bits
+*/
+int can_return_struct_as_int(size_t s)
+{
+ return s == 1 || s == 2 || s == 4;
+}
+
+int can_return_struct_as_sint64(size_t s)
+{
+ return s == 8;
+}
+
/* Perform machine dependent cif processing */
ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
{
@@ -144,9 +159,9 @@ ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
/* MSVC returns small structures in registers. Put in cif->flags
the value FFI_TYPE_STRUCT only if the structure is big enough;
otherwise, put the 4- or 8-bytes integer type. */
- if (cif->rtype->size <= 4)
+ if (can_return_struct_as_int(cif->rtype->size))
cif->flags = FFI_TYPE_INT;
- else if (cif->rtype->size <= 8)
+ else if (can_return_struct_as_sint64(cif->rtype->size))
cif->flags = FFI_TYPE_SINT64;
else
cif->flags = FFI_TYPE_STRUCT;
diff --git a/Modules/_ctypes/libffi_msvc/ffi.h b/Modules/_ctypes/libffi_msvc/ffi.h
index efb14c5f6f3a..ba74202720a6 100644
--- a/Modules/_ctypes/libffi_msvc/ffi.h
+++ b/Modules/_ctypes/libffi_msvc/ffi.h
@@ -136,6 +136,9 @@ typedef struct _ffi_type
/*@null@*/ struct _ffi_type **elements;
} ffi_type;
+int can_return_struct_as_int(size_t);
+int can_return_struct_as_sint64(size_t);
+
/* These are defined in types.c */
extern ffi_type ffi_type_void;
extern ffi_type ffi_type_uint8;
diff --git a/Modules/_ctypes/libffi_msvc/prep_cif.c b/Modules/_ctypes/libffi_msvc/prep_cif.c
index b28f895a1e46..80c5a608188d 100644
--- a/Modules/_ctypes/libffi_msvc/prep_cif.c
+++ b/Modules/_ctypes/libffi_msvc/prep_cif.c
@@ -117,7 +117,8 @@ ffi_status ffi_prep_cif(/*@out@*/ /*@partial@*/ ffi_cif *cif,
/* Make space for the return structure pointer */
if (cif->rtype->type == FFI_TYPE_STRUCT
#ifdef _WIN32
- && (cif->rtype->size > 8) /* MSVC returns small structs in registers */
+ && !can_return_struct_as_int(cif->rtype->size) /* MSVC returns small structs in registers */
+ && !can_return_struct_as_sint64(cif->rtype->size)
#endif
#ifdef SPARC
&& (cif->abi != FFI_V9 || cif->rtype->size > 32)
@@ -146,7 +147,9 @@ ffi_status ffi_prep_cif(/*@out@*/ /*@partial@*/ ffi_cif *cif,
bytes += sizeof(void*);
else
#elif defined (_WIN64)
- if ((*ptr)->type == FFI_TYPE_STRUCT && ((*ptr)->size > 8))
+ if ((*ptr)->type == FFI_TYPE_STRUCT &&
+ !can_return_struct_as_int((*ptr)->size) &&
+ !can_return_struct_as_sint64((*ptr)->size))
bytes += sizeof(void*);
else
#endif
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