Merge pull request github#9397 from MathiasVP/use-autogenerated-parent-in-cfg-library

Swift: Use the autogenerated `getParent`

Author: MathiasVP

swift/ql/lib/codeql/swift/controlflow/internal/Scope.qll

@@ -1,4 +1,5 @@
 private import swift
+private import codeql.swift.generated.GetImmediateParent
 
 module CallableBase {
   class TypeRange = @abstract_function_decl;
@@ -27,224 +28,21 @@ class Scope extends AstNode instanceof Scope::Range {
 
 cached
 private module Cached {
-  private AstNode getChild(AstNode ast) {
-    result = ast.(TopLevelCodeDecl).getBody()
-    or
-    result = ast.(AnyTryExpr).getSubExpr()
-    or
-    result = ast.(ClosureExpr).getBody()
-    or
-    result = ast.(ExplicitCastExpr).getSubExpr()
-    or
-    result = ast.(ForceValueExpr).getSubExpr()
-    or
-    result = ast.(IdentityExpr).getSubExpr()
-    or
-    result = ast.(ImplicitConversionExpr).getSubExpr()
-    or
-    result = ast.(InOutExpr).getSubExpr()
-    or
-    result = ast.(MemberRefExpr).getBaseExpr()
-    or
-    result = ast.(SelfApplyExpr).getBaseExpr()
-    or
-    result = ast.(VarargExpansionExpr).getSubExpr()
-    or
-    result = ast.(BindingPattern).getSubPattern()
-    or
-    result = ast.(EnumElementPattern).getSubPattern()
-    or
-    result = ast.(ExprPattern).getSubExpr()
-    or
-    result = ast.(IsPattern).getSubPattern()
-    or
-    result = ast.(OptionalSomePattern).getSubPattern()
-    or
-    result = ast.(ParenPattern).getSubPattern()
-    or
-    result = ast.(TypedPattern).getSubPattern()
-    or
-    result = ast.(DeferStmt).getBody()
-    or
-    result = ast.(DoStmt).getBody()
-    or
-    result = ast.(ReturnStmt).getResult()
-    or
-    result = ast.(ThrowStmt).getSubExpr()
+  /**
+   * Gets the immediate parent of a non-`AstNode` element `e`.
+   *
+   * We restrict `e` to be a non-`AstNode` to skip past non-`AstNode` in
+   * the transitive closure computation in `getParentOfAst`. This is
+   * necessary because the parent of an `AstNode` is not necessarily an `AstNode`.
+   */
+  private Element getParentOfAstStep(Element e) {
+    not e instanceof AstNode and
+    result = getImmediateParent(e)
   }
 
+  /** Gets the nearest enclosing parent of `ast` that is an `AstNode`. */
   cached
-  AstNode getChild(AstNode ast, int index) {
-    exists(AbstractFunctionDecl afd | afd = ast |
-      index = -1 and
-      result = afd.getBody()
-      or
-      result = afd.getParam(index)
-    )
-    or
-    result = ast.(EnumCaseDecl).getElement(index)
-    or
-    result = ast.(EnumElementDecl).getParam(index)
-    or
-    exists(PatternBindingDecl pbd, int i | pbd = ast |
-      index = 2 * i and
-      result = pbd.getPattern(i)
-      or
-      index = 2 * i + 1 and
-      result = pbd.getInit(i)
-    )
-    or
-    exists(ApplyExpr apply | apply = ast |
-      index = -1 and
-      result = apply.getFunction()
-      or
-      result = apply.getArgument(index).getExpr()
-    )
-    or
-    result = ast.(ArrayExpr).getElement(index)
-    or
-    // `x` is evaluated before `y` in `x = y`.
-    exists(AssignExpr assign | assign = ast |
-      index = 0 and
-      result = assign.getDest()
-      or
-      index = 1 and
-      result = assign.getSource()
-    )
-    or
-    exists(BinaryExpr binary | binary = ast |
-      index = 0 and
-      result = binary.getLeftOperand()
-      or
-      index = 1 and
-      result = binary.getRightOperand()
-    )
-    or
-    // TODO: There are two other getters. Should they be included?
-    exists(InterpolatedStringLiteralExpr interpolated | interpolated = ast |
-      index = 0 and
-      result = interpolated.getInterpolationExpr()
-      or
-      index = 1 and
-      result = interpolated.getAppendingExpr()
-    )
-    or
-    exists(KeyPathExpr kp | kp = ast |
-      index = 0 and
-      result = kp.getParsedRoot()
-      or
-      index = 1 and
-      result = kp.getParsedPath()
-    )
-    or
-    exists(SubscriptExpr sub | sub = ast |
-      index = -1 and
-      result = sub.getBaseExpr()
-      or
-      result = sub.getArgument(index).getExpr()
-    )
-    or
-    exists(TapExpr tap | tap = ast |
-      index = 0 and
-      result = tap.getVar()
-      or
-      index = 1 and
-      result = tap.getSubExpr()
-      or
-      index = 2 and
-      result = tap.getBody()
-    )
-    or
-    result = ast.(TupleExpr).getElement(index)
-    or
-    result = ast.(TuplePattern).getElement(index)
-    or
-    result = ast.(BraceStmt).getElement(index)
-    or
-    exists(CaseStmt case | case = ast |
-      index = -1 and
-      result = case.getBody()
-      or
-      result = case.getLabel(index)
-      or
-      index >= case.getNumberOfLabels() and
-      result = case.getVariable(case.getNumberOfLabels() - index)
-    )
-    or
-    exists(DoCatchStmt catch | catch = ast |
-      index = -1 and
-      result = catch.getBody()
-      or
-      result = catch.getCatch(index)
-    )
-    or
-    exists(ForEachStmt forEach | forEach = ast |
-      index = 0 and
-      result = forEach.getWhere()
-      or
-      index = 1 and
-      result = forEach.getBody()
-    )
-    or
-    exists(GuardStmt guard | guard = ast |
-      index = 0 and
-      result = guard.getBody()
-      or
-      index = 1 and
-      result = guard.getCondition()
-    )
-    or
-    exists(StmtCondition stmtCond | stmtCond = ast |
-      index = 0 and
-      result = stmtCond.getElement(index).getPattern()
-      or
-      index = 1 and
-      result = stmtCond.getElement(index).getInitializer()
-      or
-      index = 2 and
-      result = stmtCond.getElement(index).getBoolean()
-    )
-    or
-    exists(IfStmt ifStmt | ifStmt = ast |
-      index = 0 and
-      result = ifStmt.getCondition().getFullyUnresolved()
-      or
-      index = 1 and
-      result = ifStmt.getThen()
-      or
-      index = 2 and
-      result = ifStmt.getElse()
-    )
-    or
-    exists(RepeatWhileStmt repeat | repeat = ast |
-      index = 0 and
-      result = repeat.getCondition()
-      or
-      index = 1 and
-      result = repeat.getBody()
-    )
-    or
-    exists(SwitchStmt switch | switch = ast |
-      index = -1 and
-      result = switch.getExpr()
-      or
-      result = switch.getCase(index)
-    )
-    or
-    exists(WhileStmt while | while = ast |
-      index = 0 and
-      result = while.getCondition().getFullyUnresolved()
-      or
-      index = 1 and
-      result = while.getBody()
-    )
-    or
-    index = 0 and
-    result = getChild(ast)
-  }
-
-  cached
-  AstNode getParentOfAst(AstNode ast) { getChild(result, _) = ast }
+  AstNode getParentOfAst(AstNode ast) { result = getParentOfAstStep*(getImmediateParent(ast)) }
 }
 
 /** Gets the enclosing scope of a node */