Cfg: Support GotoStmt.

Author: aschackmull

java/ql/lib/semmle/code/java/ControlFlowGraph.qll

@@ -91,6 +91,10 @@ private module Ast implements AstSig<Location> {
 
   class ContinueStmt = J::ContinueStmt;
 
+  class GotoStmt extends Stmt {
+    GotoStmt() { none() }
+  }
+
   class ReturnStmt = J::ReturnStmt;
 
   class Throw = J::ThrowStmt;

shared/controlflow/codeql/controlflow/ControlFlowGraph.qll

@@ -143,6 +143,13 @@ signature module AstSig<LocationSig Location> {
    */
   class ContinueStmt extends Stmt;
 
+  /**
+   * A `goto` statement.
+   *
+   * Goto statements complete abruptly and jump to a labeled statement.
+   */
+  class GotoStmt extends Stmt;
+
   /**
    * A `return` statement.
    *
@@ -432,6 +439,8 @@ module Make0<LocationSig Location, AstSig<Location> Ast> {
       or
       n instanceof ContinueStmt
       or
+      n instanceof GotoStmt
+      or
       n instanceof Expr and
       exists(getChild(n, _)) and
       not Input1::preOrderExpr(n) and
@@ -561,6 +570,8 @@ module Make0<LocationSig Location, AstSig<Location> Ast> {
       or
       n instanceof ContinueStmt
       or
+      n instanceof GotoStmt
+      or
       n instanceof ReturnStmt
       or
       n instanceof Throw
@@ -1000,6 +1011,9 @@ module Make0<LocationSig Location, AstSig<Location> Ast> {
           or
           ast instanceof ContinueStmt and
           c.getSuccessorType() instanceof ContinueSuccessor
+          or
+          ast instanceof GotoStmt and
+          c.getSuccessorType() instanceof GotoSuccessor
         ) and
         (
           not Input1::hasLabel(ast, _) and not c.hasLabel(_)
@@ -1020,6 +1034,11 @@ module Make0<LocationSig Location, AstSig<Location> Ast> {
         )
       }
 
+      private Stmt getAStmtInBlock(AstNode block) {
+        result = block.(BlockStmt).getStmt(_) or
+        result = block.(Switch).getStmt(_)
+      }
+
       /**
        * Holds if an abrupt completion `c` from within `ast` is caught with
        * flow continuing at `n`.
@@ -1098,6 +1117,16 @@ module Make0<LocationSig Location, AstSig<Location> Ast> {
             Input1::hasLabel(switch, l)
           )
         )
+        or
+        exists(AstNode block, Input1::Label l, Stmt lblstmt |
+          ast = getAStmtInBlock(block) and
+          lblstmt = getAStmtInBlock(block) and
+          not lblstmt instanceof GotoStmt and
+          Input1::hasLabel(pragma[only_bind_into](lblstmt), l) and
+          n.isBefore(lblstmt) and
+          c.getSuccessorType() instanceof GotoSuccessor and
+          c.hasLabel(l)
+        )
       }
 
       /**