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Merge pull request #1839 from markshannon/python-rationalize-library
Python: rationalize library a bit.
2 parents 602b99e + f64f6e6 commit cac7758

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‎python/ql/src/python.qll‎

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@@ -3,7 +3,6 @@ import semmle.python.Operations
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import semmle.python.Variables
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import semmle.python.AstGenerated
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import semmle.python.AstExtended
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import semmle.python.AST
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import semmle.python.Function
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import semmle.python.Module
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import semmle.python.Class
@@ -12,7 +11,6 @@ import semmle.python.Stmts
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import semmle.python.Exprs
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import semmle.python.Keywords
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import semmle.python.Comprehensions
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import semmle.python.Lists
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import semmle.python.Flow
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import semmle.python.Metrics
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import semmle.python.Constants
@@ -28,7 +26,6 @@ import semmle.python.types.Version
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import semmle.python.types.Descriptors
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import semmle.python.protocols
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import semmle.python.SSA
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import semmle.python.Assigns
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import semmle.python.SelfAttribute
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import semmle.python.types.Properties
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import semmle.python.xml.XML

‎python/ql/src/semmle/python/AST.qll‎

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‎python/ql/src/semmle/python/Assigns.qll‎

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‎python/ql/src/semmle/python/AstExtended.qll‎

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@@ -1,5 +1,61 @@
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import python
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/** Syntactic node (Class, Function, Module, Expr, Stmt or Comprehension) corresponding to a flow node */
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abstract class AstNode extends AstNode_ {
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/** Gets the scope that this node occurs in */
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abstract Scope getScope();
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/** Gets a flow node corresponding directly to this node.
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* NOTE: For some statements and other purely syntactic elements,
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* there may not be a `ControlFlowNode` */
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ControlFlowNode getAFlowNode() {
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py_flow_bb_node(result, this, _, _)
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}
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/** Gets the location for this AST node */
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Location getLocation() {
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none()
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}
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/** Whether this syntactic element is artificial, that is it is generated
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* by the compiler and is not present in the source */
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predicate isArtificial() {
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none()
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}
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/** Gets a child node of this node in the AST. This predicate exists to aid exploration of the AST
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* and other experiments. The child-parent relation may not be meaningful.
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* For a more meaningful relation in terms of dependency use
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* Expr.getASubExpression(), Stmt.getASubStatement(), Stmt.getASubExpression() or
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* Scope.getAStmt().
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*/
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abstract AstNode getAChildNode();
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/** Gets the parent node of this node in the AST. This predicate exists to aid exploration of the AST
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* and other experiments. The child-parent relation may not be meaningful.
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* For a more meaningful relation in terms of dependency use
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* Expr.getASubExpression(), Stmt.getASubStatement(), Stmt.getASubExpression() or
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* Scope.getAStmt() applied to the parent.
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*/
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AstNode getParentNode() {
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result.getAChildNode() = this
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}
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/** Whether this contains `inner` syntactically */
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predicate contains(AstNode inner) {
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this.getAChildNode+() = inner
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}
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/** Whether this contains `inner` syntactically and `inner` has the same scope as `this` */
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predicate containsInScope(AstNode inner) {
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this.contains(inner) and
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this.getScope() = inner.getScope() and
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not inner instanceof Scope
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}
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}
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/* Parents */
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/** Internal implementation class */
@@ -116,3 +172,59 @@ class StringPartList extends StringPartList_ {
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}
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/* **** Lists ***/
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/** A parameter list */
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class ParameterList extends @py_parameter_list {
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Function getParent() {
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py_parameter_lists(this, result)
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}
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/** Gets a parameter */
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Parameter getAnItem() {
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/* Item can be a Name or a Tuple, both of which are expressions */
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py_exprs(result, _, this, _)
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}
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/** Gets the nth parameter */
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Parameter getItem(int index) {
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/* Item can be a Name or a Tuple, both of which are expressions */
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py_exprs(result, _, this, index)
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}
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string toString() {
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result = "ParameterList"
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}
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}
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/** A list of Comprehensions (for generating parts of a set, list or dictionary comprehension) */
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class ComprehensionList extends ComprehensionList_ {
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}
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/** A list of expressions */
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class ExprList extends ExprList_ {
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}
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library class DictItemList extends DictItemList_ {
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}
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library class DictItemListParent extends DictItemListParent_ {
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}
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/** A list of strings (the primitive type string not Bytes or Unicode) */
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class StringList extends StringList_ {
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}
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/** A list of aliases in an import statement */
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class AliasList extends AliasList_ {
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}
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‎python/ql/src/semmle/python/Flow.qll‎

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@@ -1,5 +1,4 @@
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import python
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import semmle.python.flow.NameNode
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private import semmle.python.pointsto.PointsTo
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/* Note about matching parent and child nodes and CFG splitting:
@@ -961,10 +960,149 @@ class RaiseStmtNode extends ControlFlowNode {
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}
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private
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predicate defined_by(NameNode def, Variable v) {
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def.defines(v) or
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exists(NameNode p | defined_by(p, v) and p.getASuccessor() = def and not p.defines(v))
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/** A control flow node corresponding to a (plain variable) name expression, such as `var`.
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* `None`, `True` and `False` are excluded.
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*/
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class NameNode extends ControlFlowNode {
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968+
NameNode() {
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exists(Name n | py_flow_bb_node(this, n, _, _))
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or
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exists(PlaceHolder p | py_flow_bb_node(this, p, _, _))
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}
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/** Whether this flow node defines the variable `v`. */
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predicate defines(Variable v) {
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exists(Name d | this.getNode() = d and d.defines(v))
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and not this.isLoad()
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}
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/** Whether this flow node deletes the variable `v`. */
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predicate deletes(Variable v) {
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exists(Name d | this.getNode() = d and d.deletes(v))
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}
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/** Whether this flow node uses the variable `v`. */
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predicate uses(Variable v) {
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this.isLoad() and exists(Name u | this.getNode() = u and u.uses(v))
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or
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exists(PlaceHolder u | this.getNode() = u and u.getVariable() = v and u.getCtx() instanceof Load)
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or
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Scopes::use_of_global_variable(this, v.getScope(), v.getId())
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}
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string getId() {
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result = this.getNode().(Name).getId()
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or
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result = this.getNode().(PlaceHolder).getId()
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}
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/** Whether this is a use of a local variable. */
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predicate isLocal() {
1002+
Scopes::local(this)
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}
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/** Whether this is a use of a non-local variable. */
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predicate isNonLocal() {
1007+
Scopes::non_local(this)
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}
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/** Whether this is a use of a global (including builtin) variable. */
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predicate isGlobal() {
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Scopes::use_of_global_variable(this, _, _)
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}
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1015+
predicate isSelf() {
1016+
exists(SsaVariable selfvar |
1017+
selfvar.isSelf() and selfvar.getAUse() = this
1018+
)
1019+
}
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1021+
}
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/** A control flow node corresponding to a named constant, one of `None`, `True` or `False`. */
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class NameConstantNode extends NameNode {
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1026+
NameConstantNode() {
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exists(NameConstant n | py_flow_bb_node(this, n, _, _))
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}
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1030+
override deprecated predicate defines(Variable v) { none() }
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override deprecated predicate deletes(Variable v) { none() }
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/* We ought to override uses as well, but that has
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* a serious performance impact.
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deprecated predicate uses(Variable v) { none() }
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*/
1038+
}
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1040+
private module Scopes {
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1042+
private predicate fast_local(NameNode n) {
1043+
exists(FastLocalVariable v |
1044+
n.uses(v) and
1045+
v.getScope() = n.getScope()
1046+
)
1047+
}
1048+
1049+
predicate local(NameNode n) {
1050+
fast_local(n)
1051+
or
1052+
exists(SsaVariable var |
1053+
var.getAUse() = n and
1054+
n.getScope() instanceof Class and
1055+
exists(var.getDefinition())
1056+
)
1057+
}
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1059+
predicate non_local(NameNode n) {
1060+
exists(FastLocalVariable flv |
1061+
flv.getALoad() = n.getNode() and
1062+
not flv.getScope() = n.getScope()
1063+
)
1064+
}
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// magic is fine, but we get questionable join-ordering of it
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pragma [nomagic]
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predicate use_of_global_variable(NameNode n, Module scope, string name) {
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n.isLoad() and
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not non_local(n)
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and
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not exists(SsaVariable var |
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var.getAUse() = n |
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var.getVariable() instanceof FastLocalVariable
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or
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n.getScope() instanceof Class and
1077+
not maybe_undefined(var)
1078+
)
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and name = n.getId()
1080+
and scope = n.getEnclosingModule()
1081+
}
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1083+
private predicate maybe_defined(SsaVariable var) {
1084+
exists(var.getDefinition()) and not py_ssa_phi(var, _) and not var.getDefinition().isDelete()
1085+
or
1086+
exists(SsaVariable input |
1087+
input = var.getAPhiInput() |
1088+
maybe_defined(input)
1089+
)
1090+
}
1091+
1092+
private predicate maybe_undefined(SsaVariable var) {
1093+
not exists(var.getDefinition()) and not py_ssa_phi(var, _)
1094+
or
1095+
var.getDefinition().isDelete()
1096+
or
1097+
maybe_undefined(var.getAPhiInput())
1098+
or
1099+
exists(BasicBlock incoming |
1100+
exists(var.getAPhiInput()) and
1101+
incoming.getASuccessor() = var.getDefinition().getBasicBlock() and
1102+
not var.getAPhiInput().getDefinition().getBasicBlock().dominates(incoming)
1103+
)
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}
1105+
9681106
}
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/** A basic block (ignoring exceptional flow edges to scope exit) */

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