Unified: Introduce CallableEx and ParameterEx

Author: hvitved

unified/ql/lib/codeql/unified/internal/CallableEx.qll

@@ -0,0 +1,335 @@
+/**
+ * Provides logic for synthesizing callables and parameters.
+ */
+
+private import unified
+private import CallableExPlugin
+private import NameBinding
+
+private predicate mayHaveImplicitConstructor(ClassLikeDeclaration cls, string name) {
+  mayHaveConstructor(cls, name) and
+  forall(ConstructorDeclaration c | c = cls.getAMember() | not constructorPreventsImplicit(c))
+}
+
+bindingset[cls]
+private predicate mayInheritConstructorFrom(ClassLikeDeclaration cls, ClassLikeDeclaration base) {
+  mayInheritConstructor(cls) and
+  mayHaveImplicitConstructor(cls, _) and
+  base.getNameNode() = getStaticBindingTargetFromRef(cls.getABaseType().getType()) and
+  mayHaveConstructor(base, _)
+}
+
+private newtype TCallableEx =
+  TAstCallableEx(Callable c) or
+  TDefaultConstructor(ClassLikeDeclaration cls, string name) {
+    mayHaveImplicitConstructor(cls, name) and
+    forall(ClassLikeDeclaration base | mayInheritConstructorFrom(cls, base) |
+      not mayHaveConstructor(cls, _)
+    )
+  } or
+  TInheritedConstructor(ClassLikeDeclaration cls, CallableEx baseCtor) {
+    exists(ClassLikeDeclaration baseClass |
+      mayInheritConstructorFrom(cls, baseClass) and
+      baseCtor.isConstructor(baseClass)
+    )
+  }
+
+private newtype TParameterEx =
+  TAstParameter(Parameter p) or
+  TImplicitReceiverParameter(Callable c) {
+    exists(LocalVariable v | v.isImplicitReceiverParameter(c))
+  } or
+  TDefaultConstructorParameter(ClassLikeDeclaration cls, int i, string name) {
+    defaultConstructorParameter(cls, i, name)
+  } or
+  TInheritedConstructorParameter(CallableEx ctor, CallableEx baseCtor, int i) {
+    ctor.isInheritedConstructor(_, baseCtor) and
+    exists(baseCtor.getParameter(i))
+  }
+
+final class CallableEx = CallableExImpl;
+
+/**
+ * A callable from source code or a synthesized callable.
+ */
+abstract private class CallableExImpl extends TCallableEx {
+  /**
+   * Gets the source code callable that this entity represents, if any.
+   */
+  Callable asCallable() { this = TAstCallableEx(result) }
+
+  /**
+   * Holds if this entity represents a default constructor for `cls`, for example a
+   * parameterless Swift `class` constructor or a Swift `struct` constructor
+   * with parameters for relevant fields.
+   */
+  predicate isDefaultConstructor(ClassLikeDeclaration cls) { this = TDefaultConstructor(cls, _) }
+
+  /**
+   * Holds if this entity represents an inherited constructor for `cls` from the
+   * base constructor `baseCtor` (which may itself be inherited).
+   */
+  predicate isInheritedConstructor(ClassLikeDeclaration cls, CallableEx baseCtor) {
+    this = TInheritedConstructor(cls, baseCtor)
+  }
+
+  /**
+   * Holds if this entity represents a constructor for `cls`.
+   */
+  predicate isConstructor(ClassLikeDeclaration cls) {
+    this.asCallable() =
+      any(ConstructorDeclaration c |
+        c = cls.getAMember() and
+        constructorPreventsImplicit(c)
+      )
+    or
+    this.isDefaultConstructor(cls)
+    or
+    this.isInheritedConstructor(cls, _)
+  }
+
+  /**
+   * Holds if this entity is a direct member of `cls`.
+   */
+  predicate isMemberOf(ClassLikeDeclaration cls) {
+    this.asCallable() = cls.getAMember()
+    or
+    this.isConstructor(cls)
+  }
+
+  /** Gets the `i`-th type parameter of this callable. */
+  abstract TypeParameter getTypeParameter(int i);
+
+  /**
+   * Gets the `i`-th parameter of this callable. Implicit receiver parameters are
+   * at index `0`, and all other parameters start at index `1`.
+   */
+  abstract ParameterEx getParameter(int i);
+
+  /** Gets a parameter of this callable. */
+  final ParameterEx getAParameter() { result = this.getParameter(_) }
+
+  /** Gets the declared return type of this callable, if any. */
+  abstract Expr getReturnType();
+
+  /** Gets the body of this callable, if any. */
+  abstract AstNode getBody();
+
+  abstract Identifier getNameNode();
+
+  /** Gets the name of this callable. */
+  abstract string getName();
+
+  /** Gets a textual representation of this callable. */
+  abstract string toString();
+
+  /** Gets the location of this callable. */
+  abstract Location getLocation();
+}
+
+private class AstCallableEx extends CallableExImpl, TAstCallableEx {
+  Callable c;
+
+  AstCallableEx() { this = TAstCallableEx(c) }
+
+  override TypeParameter getTypeParameter(int i) {
+    result = c.(FunctionDeclaration).getTypeParameter(i)
+  }
+
+  override ParameterEx getParameter(int i) {
+    result.isImplicitReceiverParameter(c) and
+    i = 0
+    or
+    exists(int j, Parameter p |
+      result.asParameter() = p and
+      j = i - 1
+    |
+      p = c.(FunctionDeclaration).getParameter(j)
+      or
+      p = c.(ConstructorDeclaration).getParameter(j)
+      or
+      p = c.(FunctionExpr).getParameter(j)
+    )
+  }
+
+  override Expr getReturnType() {
+    result = c.(FunctionDeclaration).getReturnType()
+    or
+    result = c.(FunctionExpr).getReturnType()
+  }
+
+  override AstNode getBody() { result = c.getBody() }
+
+  override Identifier getNameNode() {
+    result = c.(AccessorDeclaration).getNameNode()
+    or
+    result = c.(ConstructorDeclaration).getNameNode()
+    or
+    result = c.(FunctionDeclaration).getNameNode()
+  }
+
+  override string getName() {
+    result = this.getNameNode().getValue()
+    or
+    c instanceof DestructorDeclaration and
+    result = "<destructor>"
+    or
+    c instanceof InitializerDeclaration and
+    result = "<initializer>"
+  }
+
+  override string toString() { result = this.getName() }
+
+  override Location getLocation() { result = c.getLocation() }
+}
+
+private class DefaultConstructor extends CallableExImpl, TDefaultConstructor {
+  ClassLikeDeclaration c;
+  string name;
+
+  DefaultConstructor() { this = TDefaultConstructor(c, name) }
+
+  override TypeParameter getTypeParameter(int i) { none() }
+
+  override ParameterEx getParameter(int i) { result = TDefaultConstructorParameter(c, i, _) }
+
+  override Expr getReturnType() { none() }
+
+  override AstNode getBody() { none() }
+
+  override Identifier getNameNode() { none() }
+
+  override string getName() { result = name }
+
+  override string toString() { result = c.getName() + " [default constructor]" }
+
+  override Location getLocation() { result = c.getLocation() }
+}
+
+private class InheritedConstructor extends CallableExImpl, TInheritedConstructor {
+  ClassLikeDeclaration cls;
+  CallableEx baseCtor;
+
+  InheritedConstructor() { this = TInheritedConstructor(cls, baseCtor) }
+
+  override TypeParameter getTypeParameter(int i) { none() }
+
+  override ParameterEx getParameter(int i) {
+    result.isInheritedConstructorParameter(this, baseCtor, i)
+  }
+
+  override Expr getReturnType() { none() }
+
+  override AstNode getBody() { none() }
+
+  override Identifier getNameNode() { none() }
+
+  override string getName() { result = baseCtor.getName() }
+
+  override string toString() {
+    exists(ClassLikeDeclaration baseCls |
+      baseCtor.isMemberOf(baseCls) and
+      result = cls.getName() + " [inherited from " + baseCls.getName() + "]"
+    )
+  }
+
+  override Location getLocation() { result = cls.getLocation() }
+}
+
+final class ParameterEx = ParameterExImpl;
+
+/**
+ * A parameter from source code or a synthesized parameter.
+ */
+abstract private class ParameterExImpl extends TParameterEx {
+  /**
+   * Gets the source code parameter that this entity represents, if any.
+   */
+  Parameter asParameter() { this = TAstParameter(result) }
+
+  /**
+   * Holds if this entity represents a regular parameter from source code.
+   */
+  predicate isParameter() { exists(this.asParameter()) }
+
+  /**
+   * Holds if this entity represents an implicit receiver parameter of `c`.
+   */
+  predicate isImplicitReceiverParameter(Callable c) { this = TImplicitReceiverParameter(c) }
+
+  predicate isDefaultConstructorParameter(ClassLikeDeclaration cls, int i, string name) {
+    this = TDefaultConstructorParameter(cls, i, name)
+  }
+
+  /**
+   * Holds if this entity represents the `i`th parameter of the inherited constructor
+   * `ctor` where `baseCtor` is the base constructor.
+   */
+  predicate isInheritedConstructorParameter(CallableEx ctor, CallableEx baseCtor, int i) {
+    this = TInheritedConstructorParameter(ctor, baseCtor, i)
+  }
+
+  /** Gets a textual representation of this parameter. */
+  abstract string toString();
+
+  /** Gets the location of this parameter. */
+  abstract Location getLocation();
+}
+
+private class AstParameterEx extends ParameterExImpl, TAstParameter {
+  Parameter p;
+
+  AstParameterEx() { this = TAstParameter(p) }
+
+  override string toString() { result = p.toString() }
+
+  override Location getLocation() { result = p.getLocation() }
+}
+
+private class ImplicitReceiverParameterEx extends ParameterExImpl, TImplicitReceiverParameter {
+  Callable c;
+
+  ImplicitReceiverParameterEx() { this = TImplicitReceiverParameter(c) }
+
+  override string toString() {
+    exists(LocalVariable v |
+      v.isImplicitReceiverParameter(c) and
+      result = v.getName()
+    )
+  }
+
+  override Location getLocation() { result = c.getLocation() }
+}
+
+private class DefaultConstructorParameterEx extends ParameterExImpl, TDefaultConstructorParameter {
+  ClassLikeDeclaration c;
+  int i;
+  string name;
+
+  DefaultConstructorParameterEx() { this = TDefaultConstructorParameter(c, i, name) }
+
+  override string toString() { result = name + " [" + c.getName() + " default constructor]" }
+
+  override Location getLocation() { result = c.getLocation() }
+}
+
+private class InheritedConstructorParameterEx extends ParameterExImpl,
+  TInheritedConstructorParameter
+{
+  CallableEx ctor;
+  CallableEx baseCtor;
+  int i;
+
+  InheritedConstructorParameterEx() { this = TInheritedConstructorParameter(ctor, baseCtor, i) }
+
+  override string toString() {
+    exists(ParameterEx baseParam, ClassLikeDeclaration baseCls |
+      baseCtor.isMemberOf(baseCls) and
+      baseParam = baseCtor.getParameter(i) and
+      result =
+        "parameter " + i + " of " + ctor.getName() + " [inherited from " + baseCls.getName() + "]"
+    )
+  }
+
+  override Location getLocation() { result = ctor.getLocation() }
+}

unified/ql/lib/codeql/unified/internal/CallableExPlugin.qll

@@ -0,0 +1,56 @@
+private import unified
+private import codeql.util.Unit
+
+private module Plugins {
+  private import codeql.unified.internal.CallableExPluginSwift
+}
+
+/** Extension point for language-specific inputs to `CallableEx.qll`. */
+class CallableExPlugin extends Unit {
+  /**
+   * Holds if the class-like declaration `cls` may have a constructor with the
+   * given name.
+   */
+  predicate mayHaveConstructor(ClassLikeDeclaration cls, string name) { none() }
+
+  /**
+   * Holds if the precense of the constructor `c` prevents the class from having
+   * an implicit (default or inherited) constructor.
+   */
+  bindingset[c]
+  predicate constructorPreventsImplicit(ConstructorDeclaration c) { none() }
+
+  /**
+   * Holds if a default constructor for `cls` would need to have a parameter
+   * at index `i` with the given name. `i = 0` should be the implicit receiver
+   * parameter.
+   */
+  bindingset[cls]
+  predicate defaultConstructorParameter(ClassLikeDeclaration cls, int i, string name) { none() }
+
+  /**
+   * Holds if the class-like declaration `cls` may inherit a constructor from
+   * a base class, provided that no explicit constructor exists.
+   */
+  bindingset[cls]
+  predicate mayInheritConstructor(ClassLikeDeclaration cls) { none() }
+}
+
+predicate mayHaveConstructor(ClassLikeDeclaration cls, string name) {
+  any(CallableExPlugin p).mayHaveConstructor(cls, name)
+}
+
+bindingset[c]
+predicate constructorPreventsImplicit(ConstructorDeclaration c) {
+  any(CallableExPlugin p).constructorPreventsImplicit(c)
+}
+
+bindingset[cls]
+predicate defaultConstructorParameter(ClassLikeDeclaration cls, int i, string name) {
+  any(CallableExPlugin p).defaultConstructorParameter(cls, i, name)
+}
+
+bindingset[cls]
+predicate mayInheritConstructor(ClassLikeDeclaration cls) {
+  any(CallableExPlugin p).mayInheritConstructor(cls)
+}