C++: add getSyntheticDestructor to Expr and Stmt

Author: rdmarsh2

cpp/ql/lib/semmle/code/cpp/exprs/Expr.qll

@@ -58,6 +58,21 @@ class Expr extends StmtParent, @expr {
   /** Gets the parent of this expression, if any. */
   Element getParent() { exprparents(underlyingElement(this), _, unresolveElement(result)) }
 
+  /**
+   * Gets the `n`th compiler-generated destructor call that is performed after this expression, in
+   * order of destruction.
+   */
+  DestructorCall getSyntheticDestructor(int n) {
+    synthetic_destructor_call(this, max(int i | synthetic_destructor_call(this, i, _)) - n, result)
+  }
+
+  /**
+   * Gets a compiler-generated destructor call that is performed after this expression.
+   */
+  DestructorCall getASyntheticDestructor() {
+    synthetic_destructor_call(this, _, result)
+  }
+
   /** Gets the location of this expression. */
   override Location getLocation() {
     result = this.getExprLocationOverride()

cpp/ql/lib/semmle/code/cpp/stmts/Stmt.qll

@@ -59,6 +59,18 @@ class Stmt extends StmtParent, @stmt {
     )
   }
 
+  /**
+   * Gets the `n`th compiler-generated destructor call that is performed after this statement, in
+   * order of destruction.
+   */
+  DestructorCall getSyntheticDestructor(int n) {
+    synthetic_destructor_call(this, max(int i | synthetic_destructor_call(this, i, _)) - n, result)
+  }
+
+  DestructorCall getASyntheticDestructor() {
+    synthetic_destructor_call(this, _, result)
+  }
+
   override Location getLocation() { stmts(underlyingElement(this), _, result) }
 
   override string toString() { none() }

cpp/ql/test/library-tests/destructors/destructors.expected

@@ -0,0 +1,22 @@
+exprDestructors
+stmtDestructors
+| destructors2.cpp:24:13:24:19 | return ... | 0 | destructors2.cpp:27:5:27:5 | call to ~Class2 | destructors2.cpp:27:5:27:5 | c |
+| destructors2.cpp:27:5:27:5 | return ... | 0 | destructors2.cpp:27:5:27:5 | call to ~Inner | destructors2.cpp:27:5:27:5 | inner |
+| destructors2.cpp:27:5:27:5 | return ... | 1 | destructors2.cpp:27:5:27:5 | call to ~Class2 | destructors2.cpp:27:5:27:5 | c |
+| destructors.cpp:10:5:26:5 | { ... } | 0 | destructors.cpp:26:5:26:5 | call to ~C | destructors.cpp:26:5:26:5 | c21 |
+| destructors.cpp:10:5:26:5 | { ... } | 1 | destructors.cpp:26:5:26:5 | call to ~C | destructors.cpp:26:5:26:5 | c20 |
+| destructors.cpp:12:9:14:9 | { ... } | 0 | destructors.cpp:14:9:14:9 | call to ~C | destructors.cpp:14:9:14:9 | c30 |
+| destructors.cpp:15:9:21:9 | { ... } | 0 | destructors.cpp:21:9:21:9 | call to ~C | destructors.cpp:21:9:21:9 | c33 |
+| destructors.cpp:15:9:21:9 | { ... } | 1 | destructors.cpp:21:9:21:9 | call to ~C | destructors.cpp:21:9:21:9 | c32 |
+| destructors.cpp:15:9:21:9 | { ... } | 2 | destructors.cpp:21:9:21:9 | call to ~C | destructors.cpp:21:9:21:9 | c31 |
+| destructors.cpp:17:21:17:29 | goto ... | 0 | destructors.cpp:21:9:21:9 | call to ~C | destructors.cpp:21:9:21:9 | c31 |
+| destructors.cpp:17:21:17:29 | goto ... | 1 | destructors.cpp:26:5:26:5 | call to ~C | destructors.cpp:26:5:26:5 | c20 |
+| destructors.cpp:19:21:19:27 | return ... | 0 | destructors.cpp:21:9:21:9 | call to ~C | destructors.cpp:21:9:21:9 | c32 |
+| destructors.cpp:19:21:19:27 | return ... | 1 | destructors.cpp:21:9:21:9 | call to ~C | destructors.cpp:21:9:21:9 | c31 |
+| destructors.cpp:19:21:19:27 | return ... | 2 | destructors.cpp:26:5:26:5 | call to ~C | destructors.cpp:26:5:26:5 | c20 |
+| destructors.cpp:19:21:19:27 | return ... | 3 | destructors.cpp:35:1:35:1 | call to ~C | destructors.cpp:35:1:35:1 | c10 |
+| destructors.cpp:22:9:24:9 | { ... } | 0 | destructors.cpp:24:9:24:9 | call to ~C | destructors.cpp:24:9:24:9 | c34 |
+| destructors.cpp:27:5:29:5 | { ... } | 0 | destructors.cpp:29:5:29:5 | call to ~C | destructors.cpp:29:5:29:5 | c22 |
+| destructors.cpp:30:5:33:5 | { ... } | 0 | destructors.cpp:33:5:33:5 | call to ~C | destructors.cpp:33:5:33:5 | c23 |
+| destructors.cpp:35:1:35:1 | return ... | 0 | destructors.cpp:35:1:35:1 | call to ~C | destructors.cpp:35:1:35:1 | c11 |
+| destructors.cpp:35:1:35:1 | return ... | 1 | destructors.cpp:35:1:35:1 | call to ~C | destructors.cpp:35:1:35:1 | c10 |

cpp/ql/test/library-tests/destructors/destructors.ql

@@ -0,0 +1,11 @@
+import cpp
+
+query predicate exprDestructors(Expr e, int i, DestructorCall d, Expr destructed) {
+    d = e.getSyntheticDestructor(i) and
+    d.getQualifier() = destructed
+}
+
+query predicate stmtDestructors(Stmt s, int i, DestructorCall d, Expr destructed) {
+    d = s.getSyntheticDestructor(i) and
+    d.getQualifier() = destructed
+}