bpo-36876: Add a tool that identifies unsupported global C variables. (#15877)

Tools/c-analyzer/c_parser/info.py

@@ -0,0 +1,78 @@
+from collections import namedtuple
+
+from c_analyzer_common import info, util
+from c_analyzer_common.util import classonly, _NTBase
+
+
+def normalize_vartype(vartype):
+    """Return the canonical form for a variable type (or func signature)."""
+    # We allow empty strring through for semantic reasons.
+    if vartype is None:
+        return None
+
+    # XXX finish!
+    # XXX Return (modifiers, type, pointer)?
+    return str(vartype)
+
+
+class Variable(_NTBase,
+               namedtuple('Variable', 'id vartype')):
+    """Information about a single variable declaration."""
+
+    __slots__ = ()
+    _isglobal = util.Slot()
+
+    @classonly
+    def from_parts(cls, filename, funcname, name, vartype, isglobal=False):
+        id = info.ID(filename, funcname, name)
+        self = cls(id, vartype)
+        if isglobal:
+            self._isglobal = True
+        return self
+
+    def __new__(cls, id, vartype):
+        self = super().__new__(
+                cls,
+                id=info.ID.from_raw(id),
+                vartype=normalize_vartype(vartype) if vartype else None,
+                )
+        return self
+
+    def __hash__(self):
+        return hash(self.id)
+
+    def __getattr__(self, name):
+        return getattr(self.id, name)
+
+    def _validate_id(self):
+        if not self.id:
+            raise TypeError('missing id')
+
+        if not self.filename or self.filename == info.UNKNOWN:
+            raise TypeError(f'id missing filename ({self.id})')
+
+        if self.funcname and self.funcname == info.UNKNOWN:
+            raise TypeError(f'id missing funcname ({self.id})')
+
+        self.id.validate()
+
+    def validate(self):
+        """Fail if the object is invalid (i.e. init with bad data)."""
+        self._validate_id()
+
+        if self.vartype is None or self.vartype == info.UNKNOWN:
+            raise TypeError('missing vartype')
+
+    @property
+    def isglobal(self):
+        try:
+            return self._isglobal
+        except AttributeError:
+            # XXX Include extern variables.
+            # XXX Ignore functions.
+            self._isglobal = ('static' in self.vartype.split())
+            return self._isglobal
+
+    @property
+    def isconst(self):
+        return 'const' in self.vartype.split()