[Python-checkins] [3.8] bpo-22273: Changed conditions for ctypes array-in-struct handling. (GH-16381) (GH-16401)

Wed Sep 25 17:41:09 EDT 2019

https://github.com/python/cpython/commit/b92b8c53f63d2e805288ac2c665bf5887d1b7ca6
commit: b92b8c53f63d2e805288ac2c665bf5887d1b7ca6
branch: 3.8
author: Vinay Sajip <vinay_sajip at yahoo.co.uk>
committer: GitHub <noreply at github.com>
date: 2019年09月25日T22:41:02+01:00
summary:
[3.8] bpo-22273: Changed conditions for ctypes array-in-struct handling. (GH-16381) (GH-16401)
(cherry picked from commit c64af8fad3c4f5751af624647fbb0ce023f525dc)
files:
M Modules/_ctypes/stgdict.c

diff --git a/Modules/_ctypes/stgdict.c b/Modules/_ctypes/stgdict.c
index 62dceceb4f4e..a27d1341dc3e 100644
--- a/Modules/_ctypes/stgdict.c
+++ b/Modules/_ctypes/stgdict.c
@@ -350,9 +350,7 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
 int pack;
 Py_ssize_t ffi_ofs;
 int big_endian;
-#if defined(X86_64)
 int arrays_seen = 0;
-#endif
 
 /* HACK Alert: I cannot be bothered to fix ctypes.com, so there has to
 be a way to use the old, broken semantics: _fields_ are not extended
@@ -504,10 +502,8 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
 Py_XDECREF(pair);
 return -1;
 }
-#if defined(X86_64)
 if (PyCArrayTypeObject_Check(desc))
 arrays_seen = 1;
-#endif
 dict = PyType_stgdict(desc);
 if (dict == NULL) {
 Py_DECREF(pair);
@@ -648,8 +644,6 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
 stgdict->align = total_align;
 stgdict->length = len; /* ADD ffi_ofs? */
 
-#if defined(X86_64)
-
 #define MAX_ELEMENTS 16
 
 if (arrays_seen && (size <= 16)) {
@@ -669,6 +663,10 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
 * accurate set, to allow libffi to marshal them into registers
 * correctly. It means one more loop over the fields, but if we got
 * here, the structure is small, so there aren't too many of those.
+ *
+ * Although the passing in registers is specific to 64-bit Linux, the
+ * array-in-struct vs. pointer problem is general. But we restrict the
+ * type transformation to small structs nonetheless.
 */
 ffi_type *actual_types[MAX_ELEMENTS + 1];
 int actual_type_index = 0;
@@ -746,7 +744,6 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
 memcpy(&stgdict->ffi_type_pointer.elements[ffi_ofs], actual_types,
 actual_type_index * sizeof(ffi_type *));
 }
-#endif
 
 /* We did check that this flag was NOT set above, it must not
 have been set until now. */
