[GR-60735] Add ignored tests for ctypes return struct by value - unsupported feature for now.

PullRequest: graalpython/3624

Author: steve-s

graalpython/com.oracle.graal.python.test/src/tests/cpyext/test_ctypes.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2024, 2025, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # The Universal Permissive License (UPL), Version 1.0
@@ -37,8 +37,8 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 import ctypes
+import os.path
 import struct
-import sys
 
 from tests.cpyext import CPyExtTestCase, CPyExtType
 
@@ -126,3 +126,102 @@ def test_buffer(self):
             assert buffer.format.startswith(b'>')
             assert struct.Struct(buffer.format).size == int_format.size
             assert buffer.shape == (2, 2)
+
+# TODO: GR-60735, we cannot support this without NFI struct by value support
+def ignore_test_custom_libs():
+    # 16B: returned in registers on System V AMD64 ABI
+    class MySmallStruct1(ctypes.Structure):
+        _fields_ = [("num", ctypes.c_int64), ("str", ctypes.c_char_p)]
+
+    # 16B incl. 3B padding: not returned in registers on System V AMD64 ABI because of multiple fields
+    class MySmallStruct2(ctypes.Structure):
+        _fields_ = [("num", ctypes.c_int32), ("str", ctypes.c_char_p), ("end", ctypes.c_int8)]
+
+    class MyLargeStruct(ctypes.Structure):
+        _fields_ = [("str", ctypes.c_char_p),
+                    ("num1", ctypes.c_int32),
+                    ("num2", ctypes.c_int64),
+                    ("num3", ctypes.c_double),
+                    ("num4", ctypes.c_int16),
+                    ("num5", ctypes.c_int8),
+                    ("num6", ctypes.c_int32),
+                    ("num7", ctypes.c_int32)]
+
+    from distutils.ccompiler import new_compiler
+    import tempfile
+
+    cc = new_compiler()
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        original_cwd = os.getcwd()
+        try:
+            os.chdir(tmp_dir)
+            print(tmp_dir)
+            with open('src.c', 'x') as f:
+                f.write("""
+                    #include <stdint.h>
+
+                    typedef struct {
+                        int32_t num;
+                        const char *data;
+                    } MySmallStruct1;
+
+                    MySmallStruct1 get_small_struct1() {
+                        MySmallStruct1 s = {42, "hello world"};
+                        return s;
+                    }
+
+                    typedef struct {
+                        int32_t num;
+                        const char *data;
+                        int8_t end;
+                    } MySmallStruct2;
+
+                    MySmallStruct2 get_small_struct2() {
+                        MySmallStruct2 s = {42, "hello world", 42};
+                        return s;
+                    }
+
+                    typedef struct {
+                        const char *data;
+                        int32_t num1;
+                        int64_t num2;
+                        double num3;
+                        int16_t num4;
+                        int8_t num5;
+                        int32_t num6;
+                        int32_t num7;
+                    } MyLargeStruct;
+
+                    MyLargeStruct get_large_struct() {
+                        MyLargeStruct s = {"hello world", 42, 42, 42, 42, 42, 42, 42};
+                        return s;
+                    }
+                    """)
+            cc.compile(['src.c'])
+            cc.link_shared_lib(['src.o'], 'myshlib')
+
+            ctypes_lib = ctypes.CDLL(os.path.join(tmp_dir, 'libmyshlib.so'))
+
+            ctypes_lib.get_small_struct1.argtypes = []
+            ctypes_lib.get_small_struct1.restype = MySmallStruct1
+            result = ctypes_lib.get_small_struct1()
+            assert result.num == 42, result.num
+
+            ctypes_lib.get_small_struct2.argtypes = []
+            ctypes_lib.get_small_struct2.restype = MySmallStruct2
+            result = ctypes_lib.get_small_struct2()
+            assert result.num == 42, result.num
+            assert result.end == 42, result.end
+
+            ctypes_lib.get_large_struct.argtypes = []
+            ctypes_lib.get_large_struct.restype = MyLargeStruct
+            result = ctypes_lib.get_large_struct()
+            assert result.num1 == 42
+            assert result.num2 == 42
+            assert result.num3 == 42
+            assert result.num4 == 42
+            assert result.num5 == 42
+            assert result.num6 == 42
+            assert result.num7 == 42
+        finally:
+            os.chdir(original_cwd)

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/ctypes/CtypesModuleBuiltins.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -44,6 +44,7 @@
 import static com.oracle.graal.python.builtins.PythonBuiltinClassType.PyCFuncPtr;
 import static com.oracle.graal.python.builtins.PythonBuiltinClassType.PyCPointer;
 import static com.oracle.graal.python.builtins.PythonBuiltinClassType.PyCPointerType;
+import static com.oracle.graal.python.builtins.PythonBuiltinClassType.SystemError;
 import static com.oracle.graal.python.builtins.modules.ctypes.CDataTypeBuiltins.PyCData_GetContainer;
 import static com.oracle.graal.python.builtins.modules.ctypes.CtypesNodes.WCHAR_T_ENCODING;
 import static com.oracle.graal.python.builtins.modules.ctypes.CtypesNodes.WCHAR_T_SIZE;
@@ -1401,7 +1402,22 @@ static Object callGetFunc(VirtualFrame frame, Object restype, FFIType rtype, Obj
                     case FFI_TYPE_FLOAT -> Pointer.create(rtype, rtype.size, ilib.asFloat(result), 0);
                     case FFI_TYPE_DOUBLE -> Pointer.create(rtype, rtype.size, ilib.asDouble(result), 0);
                     case FFI_TYPE_VOID -> Pointer.NULL;
-                    case FFI_TYPE_POINTER, FFI_TYPE_STRUCT -> {
+                    case FFI_TYPE_STRUCT -> {
+                        // TODO: NFI support for structs
+                        // In case of struct, depending on the ABI the value returned from the
+                        // function may be actual struct memory (<16B and some other constraints on
+                        // SystemV AMD64 ABI, returned in two registers) or a pointer to caller
+                        // allocated buffer prepared for struct contents (larger structs), in which
+                        // case, however, the caller must allocate and pass the buffer as (hidden)
+                        // argument. We cannot get away with just using NFI pointer type as return
+                        // value for large structs, because NFI still needs to allocate and pass the
+                        // buffer for the result to the callee.
+                        CompilerDirectives.transferToInterpreterAndInvalidate();
+                        throw PRaiseNode.raiseUncached(inliningTarget, SystemError, ErrorMessages.RETURNING_STRUCT_BY_VALUE_NOT_SUPPORTED);
+                    }
+                    case FFI_TYPE_POINTER -> {
+                        // NOTE: we are returning pointer to the result buffer and the result buffer
+                        // data itself is a pointer
                         Pointer pointer;
                         if (ilib.isNull(result)) {
                             pointer = Pointer.NULL;

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/ErrorMessages.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -1185,6 +1185,7 @@ public abstract class ErrorMessages {
 
     // ctypes
     public static final TruffleString PASSING_STRUCTS_BY_VALUE_NOT_SUPPORTED = tsLiteral("Passing structs by value is not supported on NFI backend");
+    public static final TruffleString RETURNING_STRUCT_BY_VALUE_NOT_SUPPORTED = tsLiteral("ctypes: returning struct by value is not supported.");
     public static final TruffleString MEMORYVIEW_CANNOT_BE_CONVERTED_TO_NATIVE_MEMORY = tsLiteral("Memoryview cannot be converted to native memory");
     public static final TruffleString CANNOT_CONVERT_OBJECT_POINTER_TO_NATIVE = tsLiteral("Cannot convert Object pointer to native");
     public static final TruffleString CANNOT_APPLY_OFFSET_TO_AN_OBJECT_POINTER = tsLiteral("Cannot apply offset to an object pointer");