init

.venv/lib/python3.8/site-packages/mypyc/codegen/emitfunc.py

@@ -0,0 +1,618 @@
+"""Code generation for native function bodies."""
+
+from typing import Union, Optional
+from typing_extensions import Final
+
+from mypyc.common import (
+    REG_PREFIX, NATIVE_PREFIX, STATIC_PREFIX, TYPE_PREFIX, MODULE_PREFIX,
+)
+from mypyc.codegen.emit import Emitter
+from mypyc.ir.ops import (
+    OpVisitor, Goto, Branch, Return, Assign, Integer, LoadErrorValue, GetAttr, SetAttr,
+    LoadStatic, InitStatic, TupleGet, TupleSet, Call, IncRef, DecRef, Box, Cast, Unbox,
+    BasicBlock, Value, MethodCall, Unreachable, NAMESPACE_STATIC, NAMESPACE_TYPE, NAMESPACE_MODULE,
+    RaiseStandardError, CallC, LoadGlobal, Truncate, IntOp, LoadMem, GetElementPtr,
+    LoadAddress, ComparisonOp, SetMem, Register, LoadLiteral, AssignMulti, KeepAlive
+)
+from mypyc.ir.rtypes import (
+    RType, RTuple, RArray, is_tagged, is_int32_rprimitive, is_int64_rprimitive, RStruct,
+    is_pointer_rprimitive, is_int_rprimitive
+)
+from mypyc.ir.func_ir import FuncIR, FuncDecl, FUNC_STATICMETHOD, FUNC_CLASSMETHOD, all_values
+from mypyc.ir.class_ir import ClassIR
+from mypyc.ir.pprint import generate_names_for_ir
+from mypyc.analysis.blockfreq import frequently_executed_blocks
+
+# Whether to insert debug asserts for all error handling, to quickly
+# catch errors propagating without exceptions set.
+DEBUG_ERRORS = False
+
+
+def native_function_type(fn: FuncIR, emitter: Emitter) -> str:
+    args = ', '.join(emitter.ctype(arg.type) for arg in fn.args) or 'void'
+    ret = emitter.ctype(fn.ret_type)
+    return '{} (*)({})'.format(ret, args)
+
+
+def native_function_header(fn: FuncDecl, emitter: Emitter) -> str:
+    args = []
+    for arg in fn.sig.args:
+        args.append('{}{}{}'.format(emitter.ctype_spaced(arg.type), REG_PREFIX, arg.name))
+
+    return '{ret_type}{name}({args})'.format(
+        ret_type=emitter.ctype_spaced(fn.sig.ret_type),
+        name=emitter.native_function_name(fn),
+        args=', '.join(args) or 'void')
+
+
+def generate_native_function(fn: FuncIR,
+                             emitter: Emitter,
+                             source_path: str,
+                             module_name: str) -> None:
+    declarations = Emitter(emitter.context)
+    names = generate_names_for_ir(fn.arg_regs, fn.blocks)
+    body = Emitter(emitter.context, names)
+    visitor = FunctionEmitterVisitor(body, declarations, source_path, module_name)
+
+    declarations.emit_line('{} {{'.format(native_function_header(fn.decl, emitter)))
+    body.indent()
+
+    for r in all_values(fn.arg_regs, fn.blocks):
+        if isinstance(r.type, RTuple):
+            emitter.declare_tuple_struct(r.type)
+        if isinstance(r.type, RArray):
+            continue  # Special: declared on first assignment
+
+        if r in fn.arg_regs:
+            continue  # Skip the arguments
+
+        ctype = emitter.ctype_spaced(r.type)
+        init = ''
+        declarations.emit_line('{ctype}{prefix}{name}{init};'.format(ctype=ctype,
+                                                                     prefix=REG_PREFIX,
+                                                                     name=names[r],
+                                                                     init=init))
+
+    # Before we emit the blocks, give them all labels
+    blocks = fn.blocks
+    for i, block in enumerate(blocks):
+        block.label = i
+
+    common = frequently_executed_blocks(fn.blocks[0])
+
+    for i in range(len(blocks)):
+        block = blocks[i]
+        visitor.rare = block not in common
+        next_block = None
+        if i + 1 < len(blocks):
+            next_block = blocks[i + 1]
+        body.emit_label(block)
+        visitor.next_block = next_block
+        for op in block.ops:
+            op.accept(visitor)
+
+    body.emit_line('}')
+
+    emitter.emit_from_emitter(declarations)
+    emitter.emit_from_emitter(body)
+
+
+class FunctionEmitterVisitor(OpVisitor[None]):
+    def __init__(self,
+                 emitter: Emitter,
+                 declarations: Emitter,
+                 source_path: str,
+                 module_name: str) -> None:
+        self.emitter = emitter
+        self.names = emitter.names
+        self.declarations = declarations
+        self.source_path = source_path
+        self.module_name = module_name
+        self.literals = emitter.context.literals
+        self.rare = False
+        self.next_block: Optional[BasicBlock] = None
+
+    def temp_name(self) -> str:
+        return self.emitter.temp_name()
+
+    def visit_goto(self, op: Goto) -> None:
+        if op.label is not self.next_block:
+            self.emit_line('goto %s;' % self.label(op.label))
+
+    def visit_branch(self, op: Branch) -> None:
+        true, false = op.true, op.false
+        negated = op.negated
+        negated_rare = False
+        if true is self.next_block and op.traceback_entry is None:
+            # Switch true/false since it avoids an else block.
+            true, false = false, true
+            negated = not negated
+            negated_rare = True
+
+        neg = '!' if negated else ''
+        cond = ''
+        if op.op == Branch.BOOL:
+            expr_result = self.reg(op.value)
+            cond = '{}{}'.format(neg, expr_result)
+        elif op.op == Branch.IS_ERROR:
+            typ = op.value.type
+            compare = '!=' if negated else '=='
+            if isinstance(typ, RTuple):
+                # TODO: What about empty tuple?
+                cond = self.emitter.tuple_undefined_check_cond(typ,
+                                                               self.reg(op.value),
+                                                               self.c_error_value,
+                                                               compare)
+            else:
+                cond = '{} {} {}'.format(self.reg(op.value),
+                                         compare,
+                                         self.c_error_value(typ))
+        else:
+            assert False, "Invalid branch"
+
+        # For error checks, tell the compiler the branch is unlikely
+        if op.traceback_entry is not None or op.rare:
+            if not negated_rare:
+                cond = 'unlikely({})'.format(cond)
+            else:
+                cond = 'likely({})'.format(cond)
+
+        if false is self.next_block:
+            if op.traceback_entry is None:
+                self.emit_line('if ({}) goto {};'.format(cond, self.label(true)))
+            else:
+                self.emit_line('if ({}) {{'.format(cond))
+                self.emit_traceback(op)
+                self.emit_lines(
+                    'goto %s;' % self.label(true),
+                    '}'
+                )
+        else:
+            self.emit_line('if ({}) {{'.format(cond))
+            self.emit_traceback(op)
+            self.emit_lines(
+                'goto %s;' % self.label(true),
+                '} else',
+                '    goto %s;' % self.label(false)
+            )
+
+    def visit_return(self, op: Return) -> None:
+        value_str = self.reg(op.value)
+        self.emit_line('return %s;' % value_str)
+
+    def visit_tuple_set(self, op: TupleSet) -> None:
+        dest = self.reg(op)
+        tuple_type = op.tuple_type
+        self.emitter.declare_tuple_struct(tuple_type)
+        if len(op.items) == 0:  # empty tuple
+            self.emit_line('{}.empty_struct_error_flag = 0;'.format(dest))
+        else:
+            for i, item in enumerate(op.items):
+                self.emit_line('{}.f{} = {};'.format(dest, i, self.reg(item)))
+        self.emit_inc_ref(dest, tuple_type)
+
+    def visit_assign(self, op: Assign) -> None:
+        dest = self.reg(op.dest)
+        src = self.reg(op.src)
+        # clang whines about self assignment (which we might generate
+        # for some casts), so don't emit it.
+        if dest != src:
+            self.emit_line('%s = %s;' % (dest, src))
+
+    def visit_assign_multi(self, op: AssignMulti) -> None:
+        typ = op.dest.type
+        assert isinstance(typ, RArray)
+        dest = self.reg(op.dest)
+        # RArray values can only be assigned to once, so we can always
+        # declare them on initialization.
+        self.emit_line('%s%s[%d] = {%s};' % (
+            self.emitter.ctype_spaced(typ.item_type),
+            dest,
+            len(op.src),
+            ', '.join(self.reg(s) for s in op.src)))
+
+    def visit_load_error_value(self, op: LoadErrorValue) -> None:
+        if isinstance(op.type, RTuple):
+            values = [self.c_undefined_value(item) for item in op.type.types]
+            tmp = self.temp_name()
+            self.emit_line('%s %s = { %s };' % (self.ctype(op.type), tmp, ', '.join(values)))
+            self.emit_line('%s = %s;' % (self.reg(op), tmp))
+        else:
+            self.emit_line('%s = %s;' % (self.reg(op),
+                                         self.c_error_value(op.type)))
+
+    def visit_load_literal(self, op: LoadLiteral) -> None:
+        index = self.literals.literal_index(op.value)
+        s = repr(op.value)
+        if not any(x in s for x in ('/*', '*/', '\0')):
+            ann = ' /* %s */' % s
+        else:
+            ann = ''
+        if not is_int_rprimitive(op.type):
+            self.emit_line('%s = CPyStatics[%d];%s' % (self.reg(op), index, ann))
+        else:
+            self.emit_line('%s = (CPyTagged)CPyStatics[%d] | 1;%s' % (
+                self.reg(op), index, ann))
+
+    def get_attr_expr(self, obj: str, op: Union[GetAttr, SetAttr], decl_cl: ClassIR) -> str:
+        """Generate attribute accessor for normal (non-property) access.
+
+        This either has a form like obj->attr_name for attributes defined in non-trait
+        classes, and *(obj + attr_offset) for attributes defined by traits. We also
+        insert all necessary C casts here.
+        """
+        cast = '({} *)'.format(op.class_type.struct_name(self.emitter.names))
+        if decl_cl.is_trait and op.class_type.class_ir.is_trait:
+            # For pure trait access find the offset first, offsets
+            # are ordered by attribute position in the cl.attributes dict.
+            # TODO: pre-calculate the mapping to make this faster.
+            trait_attr_index = list(decl_cl.attributes).index(op.attr)
+            # TODO: reuse these names somehow?
+            offset = self.emitter.temp_name()
+            self.declarations.emit_line('size_t {};'.format(offset))
+            self.emitter.emit_line('{} = {};'.format(
+                offset,
+                'CPy_FindAttrOffset({}, {}, {})'.format(
+                    self.emitter.type_struct_name(decl_cl),
+                    '({}{})->vtable'.format(cast, obj),
+                    trait_attr_index,
+                )
+            ))
+            attr_cast = '({} *)'.format(self.ctype(op.class_type.attr_type(op.attr)))
+            return '*{}((char *){} + {})'.format(attr_cast, obj, offset)
+        else:
+            # Cast to something non-trait. Note: for this to work, all struct
+            # members for non-trait classes must obey monotonic linear growth.
+            if op.class_type.class_ir.is_trait:
+                assert not decl_cl.is_trait
+                cast = '({} *)'.format(decl_cl.struct_name(self.emitter.names))
+            return '({}{})->{}'.format(
+                cast, obj, self.emitter.attr(op.attr)
+            )
+
+    def visit_get_attr(self, op: GetAttr) -> None:
+        dest = self.reg(op)
+        obj = self.reg(op.obj)
+        rtype = op.class_type
+        cl = rtype.class_ir
+        attr_rtype, decl_cl = cl.attr_details(op.attr)
+        if cl.get_method(op.attr):
+            # Properties are essentially methods, so use vtable access for them.
+            version = '_TRAIT' if cl.is_trait else ''
+            self.emit_line('%s = CPY_GET_ATTR%s(%s, %s, %d, %s, %s); /* %s */' % (
+                dest,
+                version,
+                obj,
+                self.emitter.type_struct_name(rtype.class_ir),
+                rtype.getter_index(op.attr),
+                rtype.struct_name(self.names),
+                self.ctype(rtype.attr_type(op.attr)),
+                op.attr))
+        else:
+            # Otherwise, use direct or offset struct access.
+            attr_expr = self.get_attr_expr(obj, op, decl_cl)
+            self.emitter.emit_line('{} = {};'.format(dest, attr_expr))
+            self.emitter.emit_undefined_attr_check(
+                attr_rtype, attr_expr, '==', unlikely=True
+            )
+            exc_class = 'PyExc_AttributeError'
+            self.emitter.emit_line(
+                'PyErr_SetString({}, "attribute {} of {} undefined");'.format(
+                    exc_class, repr(op.attr), repr(cl.name)))
+            if attr_rtype.is_refcounted:
+                self.emitter.emit_line('} else {')
+                self.emitter.emit_inc_ref(attr_expr, attr_rtype)
+            self.emitter.emit_line('}')
+
+    def visit_set_attr(self, op: SetAttr) -> None:
+        dest = self.reg(op)
+        obj = self.reg(op.obj)
+        src = self.reg(op.src)
+        rtype = op.class_type
+        cl = rtype.class_ir
+        attr_rtype, decl_cl = cl.attr_details(op.attr)
+        if cl.get_method(op.attr):
+            # Again, use vtable access for properties...
+            version = '_TRAIT' if cl.is_trait else ''
+            self.emit_line('%s = CPY_SET_ATTR%s(%s, %s, %d, %s, %s, %s); /* %s */' % (
+                dest,
+                version,
+                obj,
+                self.emitter.type_struct_name(rtype.class_ir),
+                rtype.setter_index(op.attr),
+                src,
+                rtype.struct_name(self.names),
+                self.ctype(rtype.attr_type(op.attr)),
+                op.attr))
+        else:
+            # ...and struct access for normal attributes.
+            attr_expr = self.get_attr_expr(obj, op, decl_cl)
+            if attr_rtype.is_refcounted:
+                self.emitter.emit_undefined_attr_check(attr_rtype, attr_expr, '!=')
+                self.emitter.emit_dec_ref(attr_expr, attr_rtype)
+                self.emitter.emit_line('}')
+            # This steal the reference to src, so we don't need to increment the arg
+            self.emitter.emit_lines(
+                '{} = {};'.format(attr_expr, src),
+                '{} = 1;'.format(dest),
+            )
+
+    PREFIX_MAP: Final = {
+        NAMESPACE_STATIC: STATIC_PREFIX,
+        NAMESPACE_TYPE: TYPE_PREFIX,
+        NAMESPACE_MODULE: MODULE_PREFIX,
+    }
+
+    def visit_load_static(self, op: LoadStatic) -> None:
+        dest = self.reg(op)
+        prefix = self.PREFIX_MAP[op.namespace]
+        name = self.emitter.static_name(op.identifier, op.module_name, prefix)
+        if op.namespace == NAMESPACE_TYPE:
+            name = '(PyObject *)%s' % name
+        ann = ''
+        if op.ann:
+            s = repr(op.ann)
+            if not any(x in s for x in ('/*', '*/', '\0')):
+                ann = ' /* %s */' % s
+        self.emit_line('%s = %s;%s' % (dest, name, ann))
+
+    def visit_init_static(self, op: InitStatic) -> None:
+        value = self.reg(op.value)
+        prefix = self.PREFIX_MAP[op.namespace]
+        name = self.emitter.static_name(op.identifier, op.module_name, prefix)
+        if op.namespace == NAMESPACE_TYPE:
+            value = '(PyTypeObject *)%s' % value
+        self.emit_line('%s = %s;' % (name, value))
+        self.emit_inc_ref(name, op.value.type)
+
+    def visit_tuple_get(self, op: TupleGet) -> None:
+        dest = self.reg(op)
+        src = self.reg(op.src)
+        self.emit_line('{} = {}.f{};'.format(dest, src, op.index))
+        self.emit_inc_ref(dest, op.type)
+
+    def get_dest_assign(self, dest: Value) -> str:
+        if not dest.is_void:
+            return self.reg(dest) + ' = '
+        else:
+            return ''
+
+    def visit_call(self, op: Call) -> None:
+        """Call native function."""
+        dest = self.get_dest_assign(op)
+        args = ', '.join(self.reg(arg) for arg in op.args)
+        lib = self.emitter.get_group_prefix(op.fn)
+        cname = op.fn.cname(self.names)
+        self.emit_line('%s%s%s%s(%s);' % (dest, lib, NATIVE_PREFIX, cname, args))
+
+    def visit_method_call(self, op: MethodCall) -> None:
+        """Call native method."""
+        dest = self.get_dest_assign(op)
+        obj = self.reg(op.obj)
+
+        rtype = op.receiver_type
+        class_ir = rtype.class_ir
+        name = op.method
+        method = rtype.class_ir.get_method(name)
+        assert method is not None
+
+        # Can we call the method directly, bypassing vtable?
+        is_direct = class_ir.is_method_final(name)
+
+        # The first argument gets omitted for static methods and
+        # turned into the class for class methods
+        obj_args = (
+            [] if method.decl.kind == FUNC_STATICMETHOD else
+            ['(PyObject *)Py_TYPE({})'.format(obj)] if method.decl.kind == FUNC_CLASSMETHOD else
+            [obj])
+        args = ', '.join(obj_args + [self.reg(arg) for arg in op.args])
+        mtype = native_function_type(method, self.emitter)
+        version = '_TRAIT' if rtype.class_ir.is_trait else ''
+        if is_direct:
+            # Directly call method, without going through the vtable.
+            lib = self.emitter.get_group_prefix(method.decl)
+            self.emit_line('{}{}{}{}({});'.format(
+                dest, lib, NATIVE_PREFIX, method.cname(self.names), args))
+        else:
+            # Call using vtable.
+            method_idx = rtype.method_index(name)
+            self.emit_line('{}CPY_GET_METHOD{}({}, {}, {}, {}, {})({}); /* {} */'.format(
+                dest, version, obj, self.emitter.type_struct_name(rtype.class_ir),
+                method_idx, rtype.struct_name(self.names), mtype, args, op.method))
+
+    def visit_inc_ref(self, op: IncRef) -> None:
+        src = self.reg(op.src)
+        self.emit_inc_ref(src, op.src.type)
+
+    def visit_dec_ref(self, op: DecRef) -> None:
+        src = self.reg(op.src)
+        self.emit_dec_ref(src, op.src.type, is_xdec=op.is_xdec)
+
+    def visit_box(self, op: Box) -> None:
+        self.emitter.emit_box(self.reg(op.src), self.reg(op), op.src.type, can_borrow=True)
+
+    def visit_cast(self, op: Cast) -> None:
+        self.emitter.emit_cast(self.reg(op.src), self.reg(op), op.type,
+                               src_type=op.src.type)
+
+    def visit_unbox(self, op: Unbox) -> None:
+        self.emitter.emit_unbox(self.reg(op.src), self.reg(op), op.type)
+
+    def visit_unreachable(self, op: Unreachable) -> None:
+        self.emitter.emit_line('CPy_Unreachable();')
+
+    def visit_raise_standard_error(self, op: RaiseStandardError) -> None:
+        # TODO: Better escaping of backspaces and such
+        if op.value is not None:
+            if isinstance(op.value, str):
+                message = op.value.replace('"', '\\"')
+                self.emitter.emit_line(
+                    'PyErr_SetString(PyExc_{}, "{}");'.format(op.class_name, message))
+            elif isinstance(op.value, Value):
+                self.emitter.emit_line(
+                    'PyErr_SetObject(PyExc_{}, {});'.format(op.class_name,
+                                                            self.emitter.reg(op.value)))
+            else:
+                assert False, 'op value type must be either str or Value'
+        else:
+            self.emitter.emit_line('PyErr_SetNone(PyExc_{});'.format(op.class_name))
+        self.emitter.emit_line('{} = 0;'.format(self.reg(op)))
+
+    def visit_call_c(self, op: CallC) -> None:
+        if op.is_void:
+            dest = ''
+        else:
+            dest = self.get_dest_assign(op)
+        args = ', '.join(self.reg(arg) for arg in op.args)
+        self.emitter.emit_line("{}{}({});".format(dest, op.function_name, args))
+
+    def visit_truncate(self, op: Truncate) -> None:
+        dest = self.reg(op)
+        value = self.reg(op.src)
+        # for C backend the generated code are straight assignments
+        self.emit_line("{} = {};".format(dest, value))
+
+    def visit_load_global(self, op: LoadGlobal) -> None:
+        dest = self.reg(op)
+        ann = ''
+        if op.ann:
+            s = repr(op.ann)
+            if not any(x in s for x in ('/*', '*/', '\0')):
+                ann = ' /* %s */' % s
+        self.emit_line('%s = %s;%s' % (dest, op.identifier, ann))
+
+    def visit_int_op(self, op: IntOp) -> None:
+        dest = self.reg(op)
+        lhs = self.reg(op.lhs)
+        rhs = self.reg(op.rhs)
+        self.emit_line('%s = %s %s %s;' % (dest, lhs, op.op_str[op.op], rhs))
+
+    def visit_comparison_op(self, op: ComparisonOp) -> None:
+        dest = self.reg(op)
+        lhs = self.reg(op.lhs)
+        rhs = self.reg(op.rhs)
+        lhs_cast = ""
+        rhs_cast = ""
+        if op.op in (ComparisonOp.SLT, ComparisonOp.SGT, ComparisonOp.SLE, ComparisonOp.SGE):
+            # Always signed comparison op
+            lhs_cast = self.emit_signed_int_cast(op.lhs.type)
+            rhs_cast = self.emit_signed_int_cast(op.rhs.type)
+        elif op.op in (ComparisonOp.ULT, ComparisonOp.UGT, ComparisonOp.ULE, ComparisonOp.UGE):
+            # Always unsigned comparison op
+            lhs_cast = self.emit_unsigned_int_cast(op.lhs.type)
+            rhs_cast = self.emit_unsigned_int_cast(op.rhs.type)
+        elif isinstance(op.lhs, Integer) and op.lhs.value < 0:
+            # Force signed ==/!= with negative operand
+            rhs_cast = self.emit_signed_int_cast(op.rhs.type)
+        elif isinstance(op.rhs, Integer) and op.rhs.value < 0:
+            # Force signed ==/!= with negative operand
+            lhs_cast = self.emit_signed_int_cast(op.lhs.type)
+        self.emit_line('%s = %s%s %s %s%s;' % (dest, lhs_cast, lhs,
+                                               op.op_str[op.op], rhs_cast, rhs))
+
+    def visit_load_mem(self, op: LoadMem) -> None:
+        dest = self.reg(op)
+        src = self.reg(op.src)
+        # TODO: we shouldn't dereference to type that are pointer type so far
+        type = self.ctype(op.type)
+        self.emit_line('%s = *(%s *)%s;' % (dest, type, src))
+
+    def visit_set_mem(self, op: SetMem) -> None:
+        dest = self.reg(op.dest)
+        src = self.reg(op.src)
+        dest_type = self.ctype(op.dest_type)
+        # clang whines about self assignment (which we might generate
+        # for some casts), so don't emit it.
+        if dest != src:
+            self.emit_line('*(%s *)%s = %s;' % (dest_type, dest, src))
+
+    def visit_get_element_ptr(self, op: GetElementPtr) -> None:
+        dest = self.reg(op)
+        src = self.reg(op.src)
+        # TODO: support tuple type
+        assert isinstance(op.src_type, RStruct)
+        assert op.field in op.src_type.names, "Invalid field name."
+        self.emit_line('%s = (%s)&((%s *)%s)->%s;' % (dest, op.type._ctype, op.src_type.name,
+                                                      src, op.field))
+
+    def visit_load_address(self, op: LoadAddress) -> None:
+        typ = op.type
+        dest = self.reg(op)
+        src = self.reg(op.src) if isinstance(op.src, Register) else op.src
+        self.emit_line('%s = (%s)&%s;' % (dest, typ._ctype, src))
+
+    def visit_keep_alive(self, op: KeepAlive) -> None:
+        # This is a no-op.
+        pass
+
+    # Helpers
+
+    def label(self, label: BasicBlock) -> str:
+        return self.emitter.label(label)
+
+    def reg(self, reg: Value) -> str:
+        if isinstance(reg, Integer):
+            val = reg.value
+            if val == 0 and is_pointer_rprimitive(reg.type):
+                return "NULL"
+            s = str(val)
+            if val >= (1 << 31):
+                # Avoid overflowing signed 32-bit int
+                s += 'ULL'
+            elif val == -(1 << 63):
+                # Avoid overflowing C integer literal
+                s = '(-9223372036854775807LL - 1)'
+            elif val <= -(1 << 31):
+                s += 'LL'
+            return s
+        else:
+            return self.emitter.reg(reg)
+
+    def ctype(self, rtype: RType) -> str:
+        return self.emitter.ctype(rtype)
+
+    def c_error_value(self, rtype: RType) -> str:
+        return self.emitter.c_error_value(rtype)
+
+    def c_undefined_value(self, rtype: RType) -> str:
+        return self.emitter.c_undefined_value(rtype)
+
+    def emit_line(self, line: str) -> None:
+        self.emitter.emit_line(line)
+
+    def emit_lines(self, *lines: str) -> None:
+        self.emitter.emit_lines(*lines)
+
+    def emit_inc_ref(self, dest: str, rtype: RType) -> None:
+        self.emitter.emit_inc_ref(dest, rtype, rare=self.rare)
+
+    def emit_dec_ref(self, dest: str, rtype: RType, is_xdec: bool) -> None:
+        self.emitter.emit_dec_ref(dest, rtype, is_xdec=is_xdec, rare=self.rare)
+
+    def emit_declaration(self, line: str) -> None:
+        self.declarations.emit_line(line)
+
+    def emit_traceback(self, op: Branch) -> None:
+        if op.traceback_entry is not None:
+            globals_static = self.emitter.static_name('globals', self.module_name)
+            self.emit_line('CPy_AddTraceback("%s", "%s", %d, %s);' % (
+                self.source_path.replace("\\", "\\\\"),
+                op.traceback_entry[0],
+                op.traceback_entry[1],
+                globals_static))
+            if DEBUG_ERRORS:
+                self.emit_line('assert(PyErr_Occurred() != NULL && "failure w/o err!");')
+
+    def emit_signed_int_cast(self, type: RType) -> str:
+        if is_tagged(type):
+            return '(Py_ssize_t)'
+        else:
+            return ''
+
+    def emit_unsigned_int_cast(self, type: RType) -> str:
+        if is_int32_rprimitive(type):
+            return '(uint32_t)'
+        elif is_int64_rprimitive(type):
+            return '(uint64_t)'
+        else:
+            return ''