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diff --git a/lib/pycparser/ast_transforms.py b/lib/pycparser/ast_transforms.py
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+++ b/lib/pycparser/ast_transforms.py
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+#------------------------------------------------------------------------------
+# pycparser: ast_transforms.py
+#
+# Some utilities used by the parser to create a friendlier AST.
+#
+# Eli Bendersky [https://eli.thegreenplace.net/]
+# License: BSD
+#------------------------------------------------------------------------------
+
+from . import c_ast
+
+
+def fix_switch_cases(switch_node):
+    """ The 'case' statements in a 'switch' come out of parsing with one
+        child node, so subsequent statements are just tucked to the parent
+        Compound. Additionally, consecutive (fall-through) case statements
+        come out messy. This is a peculiarity of the C grammar. The following:
+
+            switch (myvar) {
+                case 10:
+                    k = 10;
+                    p = k + 1;
+                    return 10;
+                case 20:
+                case 30:
+                    return 20;
+                default:
+                    break;
+            }
+
+        Creates this tree (pseudo-dump):
+
+            Switch
+                ID: myvar
+                Compound:
+                    Case 10:
+                        k = 10
+                    p = k + 1
+                    return 10
+                    Case 20:
+                        Case 30:
+                            return 20
+                    Default:
+                        break
+
+        The goal of this transform is to fix this mess, turning it into the
+        following:
+
+            Switch
+                ID: myvar
+                Compound:
+                    Case 10:
+                        k = 10
+                        p = k + 1
+                        return 10
+                    Case 20:
+                    Case 30:
+                        return 20
+                    Default:
+                        break
+
+        A fixed AST node is returned. The argument may be modified.
+    """
+    assert isinstance(switch_node, c_ast.Switch)
+    if not isinstance(switch_node.stmt, c_ast.Compound):
+        return switch_node
+
+    # The new Compound child for the Switch, which will collect children in the
+    # correct order
+    new_compound = c_ast.Compound([], switch_node.stmt.coord)
+
+    # The last Case/Default node
+    last_case = None
+
+    # Goes over the children of the Compound below the Switch, adding them
+    # either directly below new_compound or below the last Case as appropriate
+    # (for `switch(cond) {}`, block_items would have been None)
+    for child in (switch_node.stmt.block_items or []):
+        if isinstance(child, (c_ast.Case, c_ast.Default)):
+            # If it's a Case/Default:
+            # 1. Add it to the Compound and mark as "last case"
+            # 2. If its immediate child is also a Case or Default, promote it
+            #    to a sibling.
+            new_compound.block_items.append(child)
+            _extract_nested_case(child, new_compound.block_items)
+            last_case = new_compound.block_items[-1]
+        else:
+            # Other statements are added as children to the last case, if it
+            # exists.
+            if last_case is None:
+                new_compound.block_items.append(child)
+            else:
+                last_case.stmts.append(child)
+
+    switch_node.stmt = new_compound
+    return switch_node
+
+
+def _extract_nested_case(case_node, stmts_list):
+    """ Recursively extract consecutive Case statements that are made nested
+        by the parser and add them to the stmts_list.
+    """
+    if isinstance(case_node.stmts[0], (c_ast.Case, c_ast.Default)):
+        stmts_list.append(case_node.stmts.pop())
+        _extract_nested_case(stmts_list[-1], stmts_list)
+
+
+def fix_atomic_specifiers(decl):
+    """ Atomic specifiers like _Atomic(type) are unusually structured,
+        conferring a qualifier upon the contained type.
+
+        This function fixes a decl with atomic specifiers to have a sane AST
+        structure, by removing spurious Typename->TypeDecl pairs and attaching
+        the _Atomic qualifier in the right place.
+    """
+    # There can be multiple levels of _Atomic in a decl; fix them until a
+    # fixed point is reached.
+    while True:
+        decl, found = _fix_atomic_specifiers_once(decl)
+        if not found:
+            break
+
+    # Make sure to add an _Atomic qual on the topmost decl if needed. Also
+    # restore the declname on the innermost TypeDecl (it gets placed in the
+    # wrong place during construction).
+    typ = decl
+    while not isinstance(typ, c_ast.TypeDecl):
+        try:
+            typ = typ.type
+        except AttributeError:
+            return decl
+    if '_Atomic' in typ.quals and '_Atomic' not in decl.quals:
+        decl.quals.append('_Atomic')
+    if typ.declname is None:
+        typ.declname = decl.name
+
+    return decl
+
+
+def _fix_atomic_specifiers_once(decl):
+    """ Performs one 'fix' round of atomic specifiers.
+        Returns (modified_decl, found) where found is True iff a fix was made.
+    """
+    parent = decl
+    grandparent = None
+    node = decl.type
+    while node is not None:
+        if isinstance(node, c_ast.Typename) and '_Atomic' in node.quals:
+            break
+        try:
+            grandparent = parent
+            parent = node
+            node = node.type
+        except AttributeError:
+            # If we've reached a node without a `type` field, it means we won't
+            # find what we're looking for at this point; give up the search
+            # and return the original decl unmodified.
+            return decl, False
+
+    assert isinstance(parent, c_ast.TypeDecl)
+    grandparent.type = node.type
+    if '_Atomic' not in node.type.quals:
+        node.type.quals.append('_Atomic')
+    return decl, True