C#: Add downgrade script.

Author: michaelnebel

csharp/downgrades/19b8cc3e2dc768d4cbc03d6e3773b709bbebd036/assignments.ql

@@ -0,0 +1,178 @@
+class Expr extends @expr {
+  string toString() { none() }
+}
+
+class Location extends @location {
+  string toString() { none() }
+}
+
+newtype TAddedElement =
+  TAssignment(Expr e) or
+  TLhs(Expr e) or
+  TRhs(Expr e)
+
+module Fresh = QlBuiltins::NewEntity<TAddedElement>;
+
+class TNewExpr = @expr or Fresh::EntityId;
+
+class NewExpr extends TNewExpr {
+  string toString() { none() }
+}
+
+class TNewControlFlowElement = @control_flow_element or Fresh::EntityId;
+
+class NewControlFlowElement extends TNewControlFlowElement {
+  string toString() { none() }
+}
+
+class TypeOrRef extends @type_or_ref {
+  string toString() { none() }
+}
+
+class Callable extends @callable {
+  string toString() { none() }
+}
+
+class Accessible extends @accessible {
+  string toString() { none() }
+}
+
+predicate assignmentKind(int kind) {
+  // | 63 = @simple_assign_expr
+  // | 80 = @add_event_expr
+  // | 81 = @remove_event_expr
+  // | 83 = @local_var_decl_expr
+  kind = [63, 80, 81, 83]
+}
+
+predicate compoundAssignmentKind(int kind) {
+  // | 64 = @assign_add_expr
+  // | 65 = @assign_sub_expr
+  // | 66 = @assign_mul_expr
+  // | 67 = @assign_div_expr
+  // | 68 = @assign_rem_expr
+  // | 69 = @assign_and_expr
+  // | 70 = @assign_xor_expr
+  // | 71 = @assign_or_expr
+  // | 72 = @assign_lshift_expr
+  // | 73 = @assign_rshift_expr
+  // | 119 = @assign_coalesce_expr
+  // | 134 = @assign_urshift_expr
+  kind = [64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 119, 134]
+}
+
+int getOperatorKindFromAssignmentKind(int kind) {
+  kind = 64 and result = 44 // @assign_add_expr -> @add_expr
+  or
+  kind = 65 and result = 45 // @assign_sub_expr -> @sub_expr
+  or
+  kind = 66 and result = 41 // @assign_mul_expr -> @mul_expr
+  or
+  kind = 67 and result = 42 // @assign_div_expr -> @div_expr
+  or
+  kind = 68 and result = 43 // @assign_rem_expr -> @rem_expr
+  or
+  kind = 69 and result = 54 // @assign_and_expr -> @bit_and_expr
+  or
+  kind = 70 and result = 55 // @assign_xor_expr -> @bit_xor_expr
+  or
+  kind = 71 and result = 56 // @assign_or_expr -> @bit_or_expr
+  or
+  kind = 72 and result = 46 // @assign_lshift_expr -> @lshift_expr
+  or
+  kind = 73 and result = 47 // @assign_rshift_expr -> @rshift_expr
+  or
+  kind = 119 and result = 61 // @assign_coalesce_expr -> @coalesce_expr
+  or
+  kind = 134 and result = 133 // @assign_urshift_expr -> @urshift_expr
+}
+
+predicate isAssignment(Expr ass) {
+  exists(int kind | assignmentKind(kind) | expressions(ass, kind, _))
+}
+
+class CompoundAssignmentExpr extends Expr {
+  CompoundAssignmentExpr() {
+    exists(int kind | compoundAssignmentKind(kind) | expressions(this, kind, _))
+  }
+}
+
+query predicate new_expressions(NewExpr e, int kind, TypeOrRef t) {
+  expressions(e, kind, t)
+  or
+  // Introduce expanded expression nodes.
+  exists(CompoundAssignmentExpr compound, int kind0, Expr e1, int kind1 |
+    expressions(compound, kind0, t) and
+    compoundAssignmentKind(kind0) and
+    expressions(e1, kind1, _) and
+    expr_parent(e1, 0, compound)
+  |
+    Fresh::map(TAssignment(compound)) = e and kind = 63
+    or
+    Fresh::map(TLhs(compound)) = e and kind = kind1
+    or
+    Fresh::map(TRhs(compound)) = e and kind = getOperatorKindFromAssignmentKind(kind0)
+  )
+}
+
+query predicate new_expr_parent(NewExpr e, int child, NewControlFlowElement parent) {
+  if isAssignment(parent)
+  then
+    // Swap children for assignments, local variable declarations and add/remove event.
+    child = 0 and expr_parent(e, 1, parent)
+    or
+    child = 1 and expr_parent(e, 0, parent)
+  else (
+    exists(CompoundAssignmentExpr compound |
+      Fresh::map(TAssignment(compound)) = e and child = 2 and parent = compound
+      or
+      Fresh::map(TLhs(compound)) = e and child = 1 and parent = Fresh::map(TAssignment(compound))
+      or
+      Fresh::map(TRhs(compound)) = e and child = 0 and parent = Fresh::map(TAssignment(compound))
+      or
+      expr_parent(e, child, compound) and parent = Fresh::map(TRhs(compound))
+    )
+    or
+    // Copy the expr_parent relation except for compound assignment edges.
+    expr_parent(e, child, parent) and not parent instanceof CompoundAssignmentExpr
+  )
+}
+
+query predicate new_expr_location(NewExpr e, Location loc) {
+  expr_location(e, loc)
+  or
+  exists(CompoundAssignmentExpr compound |
+    Fresh::map(TAssignment(compound)) = e and expr_location(compound, loc)
+    or
+    Fresh::map(TLhs(compound)) = e and
+    exists(Expr child | expr_location(child, loc) and expr_parent(child, 0, compound))
+    or
+    Fresh::map(TRhs(compound)) = e and expr_location(compound, loc)
+  )
+}
+
+query predicate new_expr_call(NewExpr e, Callable c) {
+  expr_call(e, c) and not e instanceof CompoundAssignmentExpr
+  or
+  exists(CompoundAssignmentExpr compound |
+    Fresh::map(TRhs(compound)) = e and expr_call(compound, c)
+  )
+}
+
+query predicate new_dynamic_member_name(NewExpr e, string name) {
+  dynamic_member_name(e, name) and not e instanceof CompoundAssignmentExpr
+  or
+  exists(CompoundAssignmentExpr compound |
+    Fresh::map(TRhs(compound)) = e and dynamic_member_name(compound, name)
+  )
+}
+
+query predicate new_expr_access(NewExpr e, Accessible a) {
+  expr_access(e, a)
+  or
+  exists(CompoundAssignmentExpr compound, Expr access |
+    expr_parent(access, 0, compound) and
+    expr_access(access, a) and
+    Fresh::map(TLhs(compound)) = e
+  )
+}