Swift: Add support for pointwise assignment operators.

Author: geoffw0

swift/ql/lib/codeql/swift/elements/expr/AssignExpr.qll

@@ -13,7 +13,8 @@ class Assignment extends Expr {
   Assignment() {
     this instanceof AssignExpr or
     this instanceof AssignArithmeticOperationEx or
-    this instanceof AssignBitwiseOperationEx
+    this instanceof AssignBitwiseOperationEx or
+    this instanceof AssignPointwiseOperationEx
   }
 
   /**
@@ -71,7 +72,8 @@ class AssignExpr extends Generated::AssignExpr {
 class AssignOperation extends Assignment, BinaryExpr {
   AssignOperation() {
     this instanceof AssignArithmeticOperationEx or
-    this instanceof AssignBitwiseOperationEx
+    this instanceof AssignBitwiseOperationEx or
+    this instanceof AssignPointwiseOperationEx
   }
 }
 
@@ -103,6 +105,19 @@ class AssignBitwiseOperation extends AssignOperation instanceof AssignBitwiseOpe
  */
 abstract private class AssignBitwiseOperationEx extends BinaryExpr { }
 
+/**
+ * A pointwise assignment expression. For example:
+ * ```
+ * x .&= y
+ * ```
+ */
+class AssignPointwiseOperation extends AssignOperation instanceof AssignPointwiseOperationEx { }
+
+/**
+ * Private abstract class, extended to define the scope of `AssignPointwiseOperation`.
+ */
+abstract private class AssignPointwiseOperationEx extends BinaryExpr { }
+
 /**
  * An addition assignment expression:
  * ```
@@ -227,3 +242,39 @@ class AssignXorExpr extends AssignBitwiseOperationEx {
 
   override string toString() { result = "... ^= ..." }
 }
+
+/**
+ * A pointwise bitwise-and assignment expression:
+ * ```
+ * a .&= b
+ * ```
+ */
+class AssignPointwiseAndExpr extends AssignPointwiseOperationEx {
+  AssignPointwiseAndExpr() { this.getOperator().getName() = ".&=(_:_:)" }
+
+  override string toString() { result = "... .&= ..." }
+}
+
+/**
+ * A pointwise bitwise-or assignment expression:
+ * ```
+ * a .|= b
+ * ```
+ */
+class AssignPointwiseOrExpr extends AssignPointwiseOperationEx {
+  AssignPointwiseOrExpr() { this.getOperator().getName() = ".|=(_:_:)" }
+
+  override string toString() { result = "... .|= ..." }
+}
+
+/**
+ * A pointwise bitwise exclusive-or assignment expression:
+ * ```
+ * a .^= b
+ * ```
+ */
+class AssignPointwiseXorExpr extends AssignPointwiseOperationEx {
+  AssignPointwiseXorExpr() { this.getOperator().getName() = ".^=(_:_:)" }
+
+  override string toString() { result = "... .^= ..." }
+}

swift/ql/test/library-tests/elements/expr/assignment/assignment.expected

@@ -15,3 +15,6 @@
 | assignment.swift:26:2:26:9 | ... <<= ... | AssignBitwiseOperation, AssignLShiftExpr, AssignOperation, Assignment, hasOverflowOperator | &... | 1 |
 | assignment.swift:27:2:27:9 | ... >>= ... | AssignBitwiseOperation, AssignOperation, AssignRShiftExpr, Assignment, hasOverflowOperator | &... | 1 |
 | assignment.swift:33:2:33:6 |  ... = ... | AssignExpr, Assignment | y | z |
+| assignment.swift:34:2:34:8 | ... .&= ... | AssignOperation, AssignPointwiseAndExpr, Assignment | &... | m |
+| assignment.swift:35:2:35:8 | ... .\|= ... | AssignOperation, AssignPointwiseOrExpr, Assignment | &... | m |
+| assignment.swift:36:2:36:8 | ... .^= ... | AssignOperation, AssignPointwiseXorExpr, Assignment | &... | m |

swift/ql/test/library-tests/elements/expr/assignment/assignment.ql

@@ -31,6 +31,12 @@ string describe(Expr e) {
   or
   e instanceof AssignXorExpr and result = "AssignXorExpr"
   or 
+  e instanceof AssignPointwiseAndExpr and result = "AssignPointwiseAndExpr"
+  or
+  e instanceof AssignPointwiseOrExpr and result = "AssignPointwiseOrExpr"
+  or
+  e instanceof AssignPointwiseXorExpr and result = "AssignPointwiseXorExpr"
+  or
   e.(Assignment).hasOverflowOperator() and result = "hasOverflowOperator"
 }