[mypyc] Refactor: make LoadMem not borrow by default

mypyc/codegen/emitfunc.py

@@ -791,6 +791,8 @@ def visit_load_mem(self, op: LoadMem) -> None:
         # TODO: we shouldn't dereference to type that are pointer type so far
         type = self.ctype(op.type)
         self.emit_line(f"{dest} = *({type} *){src};")
+        if not op.is_borrowed:
+            self.emit_inc_ref(dest, op.type)
 
     def visit_set_mem(self, op: SetMem) -> None:
         dest = self.reg(op.dest)

mypyc/ir/ops.py

@@ -1558,14 +1558,13 @@ class LoadMem(RegisterOp):
 
     error_kind = ERR_NEVER
 
-    def __init__(self, type: RType, src: Value, line: int = -1) -> None:
+    def __init__(self, type: RType, src: Value, line: int = -1, *, borrow: bool = False) -> None:
         super().__init__(line)
         self.type = type
-        # TODO: for now we enforce that the src memory address should be Py_ssize_t
-        #       later we should also support same width unsigned int
+        # TODO: Support other native integer types
         assert is_pointer_rprimitive(src.type)
         self.src = src
-        self.is_borrowed = True
+        self.is_borrowed = borrow and type.is_refcounted
 
     def sources(self) -> list[Value]:
         return [self.src]

mypyc/ir/pprint.py

@@ -265,7 +265,9 @@ def visit_float_comparison_op(self, op: FloatComparisonOp) -> str:
         return self.format("%r = %r %s %r", op, op.lhs, op.op_str[op.op], op.rhs)
 
     def visit_load_mem(self, op: LoadMem) -> str:
-        return self.format("%r = load_mem %r :: %t*", op, op.src, op.type)
+        return self.format(
+            "%r = %sload_mem %r :: %t*", op, self.borrow_prefix(op), op.src, op.type
+        )
 
     def visit_set_mem(self, op: SetMem) -> str:
         return self.format("set_mem %r, %r :: %t*", op.dest, op.src, op.dest_type)

mypyc/irbuild/for_helpers.py

@@ -733,7 +733,7 @@ def gen_condition(self) -> None:
 
         def except_match() -> Value:
             addr = builder.add(LoadAddress(pointer_rprimitive, stop_async_iteration_op.src, line))
-            return builder.add(LoadMem(stop_async_iteration_op.type, addr))
+            return builder.add(LoadMem(stop_async_iteration_op.type, addr, borrow=True))
 
         def try_body() -> None:
             awaitable = builder.call_c(anext_op, [builder.read(self.iter_target)], line)

mypyc/irbuild/ll_builder.py

@@ -286,6 +286,9 @@ def goto_and_activate(self, block: BasicBlock) -> None:
     def keep_alive(self, values: list[Value], *, steal: bool = False) -> None:
         self.add(KeepAlive(values, steal=steal))
 
+    def load_mem(self, ptr: Value, value_type: RType, *, borrow: bool = False) -> Value:
+        return self.add(LoadMem(value_type, ptr, borrow=borrow))
+
     def push_error_handler(self, handler: BasicBlock | None) -> None:
         self.error_handlers.append(handler)
 
@@ -660,7 +663,7 @@ def other() -> Value:
 
     def get_type_of_obj(self, obj: Value, line: int) -> Value:
         ob_type_address = self.add(GetElementPtr(obj, PyObject, "ob_type", line))
-        ob_type = self.add(LoadMem(object_rprimitive, ob_type_address))
+        ob_type = self.load_mem(ob_type_address, object_rprimitive, borrow=True)
         self.add(KeepAlive([obj]))
         return ob_type
 
@@ -2261,7 +2264,7 @@ def builtin_len(self, val: Value, line: int, use_pyssize_t: bool = False) -> Val
             size_value = self.primitive_op(var_object_size, [val], line)
         elif is_set_rprimitive(typ) or is_frozenset_rprimitive(typ):
             elem_address = self.add(GetElementPtr(val, PySetObject, "used"))
-            size_value = self.add(LoadMem(c_pyssize_t_rprimitive, elem_address))
+            size_value = self.load_mem(elem_address, c_pyssize_t_rprimitive)
             self.add(KeepAlive([val]))
         elif is_dict_rprimitive(typ):
             size_value = self.call_c(dict_ssize_t_size_op, [val], line)

mypyc/lower/list_ops.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from mypyc.common import PLATFORM_SIZE
-from mypyc.ir.ops import GetElementPtr, IncRef, Integer, IntOp, LoadMem, SetMem, Value
+from mypyc.ir.ops import GetElementPtr, Integer, IntOp, SetMem, Value
 from mypyc.ir.rtypes import (
     PyListObject,
     c_pyssize_t_rprimitive,
@@ -42,7 +42,7 @@ def buf_init_item(builder: LowLevelIRBuilder, args: list[Value], line: int) -> V
 @lower_primitive_op("list_items")
 def list_items(builder: LowLevelIRBuilder, args: list[Value], line: int) -> Value:
     ob_item_ptr = builder.add(GetElementPtr(args[0], PyListObject, "ob_item", line))
-    return builder.add(LoadMem(pointer_rprimitive, ob_item_ptr, line))
+    return builder.load_mem(ob_item_ptr, pointer_rprimitive)
 
 
 def list_item_ptr(builder: LowLevelIRBuilder, obj: Value, index: Value, line: int) -> Value:
@@ -68,6 +68,4 @@ def list_item_ptr(builder: LowLevelIRBuilder, obj: Value, index: Value, line: in
 def list_get_item_unsafe(builder: LowLevelIRBuilder, args: list[Value], line: int) -> Value:
     index = builder.coerce(args[1], c_pyssize_t_rprimitive, line)
     item_ptr = list_item_ptr(builder, args[0], index, line)
-    value = builder.add(LoadMem(object_rprimitive, item_ptr, line))
-    builder.add(IncRef(value))
-    return value
+    return builder.load_mem(item_ptr, object_rprimitive)

mypyc/test-data/irbuild-classes.test

@@ -363,7 +363,7 @@ def f(x):
 L0:
     r0 = __main__.B :: type
     r1 = get_element_ptr x ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive x
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool
@@ -402,7 +402,7 @@ def f(x):
 L0:
     r0 = __main__.A :: type
     r1 = get_element_ptr x ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive x
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool
@@ -412,7 +412,7 @@ L1:
 L2:
     r5 = __main__.B :: type
     r6 = get_element_ptr x ob_type :: PyObject
-    r7 = load_mem r6 :: builtins.object*
+    r7 = borrow load_mem r6 :: builtins.object*
     keep_alive x
     r8 = r7 == r5
     r4 = r8
@@ -449,7 +449,7 @@ def f(x):
 L0:
     r0 = __main__.A :: type
     r1 = get_element_ptr x ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive x
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool
@@ -459,7 +459,7 @@ L1:
 L2:
     r5 = __main__.R :: type
     r6 = get_element_ptr x ob_type :: PyObject
-    r7 = load_mem r6 :: builtins.object*
+    r7 = borrow load_mem r6 :: builtins.object*
     keep_alive x
     r8 = r7 == r5
     r4 = r8
@@ -500,7 +500,7 @@ def f(x):
 L0:
     r0 = __main__.A :: type
     r1 = get_element_ptr x ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive x
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool
@@ -510,7 +510,7 @@ L1:
 L2:
     r5 = __main__.C :: type
     r6 = get_element_ptr x ob_type :: PyObject
-    r7 = load_mem r6 :: builtins.object*
+    r7 = borrow load_mem r6 :: builtins.object*
     keep_alive x
     r8 = r7 == r5
     r4 = r8

mypyc/test-data/irbuild-isinstance.test

@@ -97,7 +97,7 @@ L0:
     x = r0
     r1 = __main__.C :: type
     r2 = get_element_ptr x ob_type :: PyObject
-    r3 = load_mem r2 :: builtins.object*
+    r3 = borrow load_mem r2 :: builtins.object*
     keep_alive x
     r4 = r3 == r1
     if r4 goto L1 else goto L2 :: bool

mypyc/test-data/irbuild-optional.test

@@ -317,7 +317,7 @@ def get(o):
 L0:
     r0 = __main__.A :: type
     r1 = get_element_ptr o ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive o
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool
@@ -396,7 +396,7 @@ def g(o):
 L0:
     r0 = __main__.A :: type
     r1 = get_element_ptr o ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive o
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool
@@ -409,7 +409,7 @@ L1:
 L2:
     r8 = __main__.B :: type
     r9 = get_element_ptr o ob_type :: PyObject
-    r10 = load_mem r9 :: builtins.object*
+    r10 = borrow load_mem r9 :: builtins.object*
     keep_alive o
     r11 = r10 == r8
     if r11 goto L3 else goto L4 :: bool
@@ -462,7 +462,7 @@ def f(o):
 L0:
     r0 = __main__.A :: type
     r1 = get_element_ptr o ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive o
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool
@@ -494,7 +494,7 @@ def g(o):
 L0:
     r0 = __main__.A :: type
     r1 = get_element_ptr o ob_type :: PyObject
-    r2 = load_mem r1 :: builtins.object*
+    r2 = borrow load_mem r1 :: builtins.object*
     keep_alive o
     r3 = r2 == r0
     if r3 goto L1 else goto L2 :: bool

mypyc/test-data/irbuild-singledispatch.test

@@ -57,7 +57,7 @@ def f_obj.__call__(__mypyc_self__, arg):
     r27 :: bool
 L0:
     r0 = get_element_ptr arg ob_type :: PyObject
-    r1 = load_mem r0 :: builtins.object*
+    r1 = borrow load_mem r0 :: builtins.object*
     keep_alive arg
     r2 = __mypyc_self__.dispatch_cache
     r3 = CPyDict_GetWithNone(r2, r1)
@@ -82,7 +82,7 @@ L2:
 L3:
     r16 = load_address PyLong_Type
     r17 = get_element_ptr r6 ob_type :: PyObject
-    r18 = load_mem r17 :: builtins.object*
+    r18 = borrow load_mem r17 :: builtins.object*
     keep_alive r6
     r19 = r18 == r16
     if r19 goto L4 else goto L7 :: bool
@@ -195,7 +195,7 @@ def f_obj.__call__(__mypyc_self__, x):
     r24 :: None
 L0:
     r0 = get_element_ptr x ob_type :: PyObject
-    r1 = load_mem r0 :: builtins.object*
+    r1 = borrow load_mem r0 :: builtins.object*
     keep_alive x
     r2 = __mypyc_self__.dispatch_cache
     r3 = CPyDict_GetWithNone(r2, r1)
@@ -220,7 +220,7 @@ L2:
 L3:
     r16 = load_address PyLong_Type
     r17 = get_element_ptr r6 ob_type :: PyObject
-    r18 = load_mem r17 :: builtins.object*
+    r18 = borrow load_mem r17 :: builtins.object*
     keep_alive r6
     r19 = r18 == r16
     if r19 goto L4 else goto L5 :: bool

mypyc/test-data/lowering-int.test

@@ -365,7 +365,6 @@ L2:
     r6 = r0 * 8
     r7 = r5 + r6
     r8 = load_mem r7 :: builtins.object*
-    inc_ref r8
     r9 = unbox(int, r8)
     dec_ref r8
     if is_error(r9) goto L6 (error at f:4) else goto L3

mypyc/test-data/refcount.test

@@ -1117,7 +1117,7 @@ L0:
     r0 = borrow x.a
     r1 = __main__.D :: type
     r2 = get_element_ptr r0 ob_type :: PyObject
-    r3 = load_mem r2 :: builtins.object*
+    r3 = borrow load_mem r2 :: builtins.object*
     r4 = r3 == r1
     if r4 goto L1 else goto L2 :: bool
 L1: