C++: Remove abstraction of OperatorNew/DeleteAllocationFunction.

geoffw0 · geoffw0 · commit 5359e134213d · 2020-11-11T15:35:34.000Z
diff --git a/cpp/ql/src/semmle/code/cpp/models/implementations/Allocation.qll b/cpp/ql/src/semmle/code/cpp/models/implementations/Allocation.qll
@@ -236,34 +236,6 @@ private class SizelessAllocationFunction extends AllocationFunction {
   }
 }
 
-/**
- * Implements `OperatorNewAllocationFunction`.
- */
-private class OperatorNewAllocationFunctionImpl extends OperatorNewAllocationFunction {
-  OperatorNewAllocationFunctionImpl() {
-    exists(string name |
-      hasGlobalName(name) and
-      (
-        // operator new(bytes, ...)
-        name = "operator new"
-        or
-        // operator new[](bytes, ...)
-        name = "operator new[]"
-      )
-    )
-  }
-
-  override int getSizeArg() { result = 0 }
-
-  override predicate requiresDealloc() { not exists(getPlacementArgument()) }
-
-  override int getPlacementArgument() {
-    getNumberOfParameters() = 2 and
-    getParameter(1).getType() instanceof VoidPointerType and
-    result = 1
-  }
-}
-
 /**
  * Holds if `sizeExpr` is an expression consisting of a subexpression
  * `lengthExpr` multiplied by a constant `sizeof` that is the result of a
diff --git a/cpp/ql/src/semmle/code/cpp/models/implementations/Deallocation.qll b/cpp/ql/src/semmle/code/cpp/models/implementations/Deallocation.qll
@@ -89,26 +89,6 @@ private class StandardDeallocationFunction extends DeallocationFunction {
   override int getFreedArg() { result = freedArg }
 }
 
-/**
- * Implements `OperatorDeleteDeallocationFunction`.
- */
-private class OperatorDeleteDeallocationFunctionImpl extends OperatorDeleteDeallocationFunction {
-  OperatorDeleteDeallocationFunctionImpl() {
-    exists(string name |
-      hasGlobalName(name) and
-      (
-        // operator delete(pointer, ...)
-        name = "operator delete"
-        or
-        // operator delete[](pointer, ...)
-        name = "operator delete[]"
-      )
-    )
-  }
-
-  override int getFreedArg() { result = 0 }
-}
-
 /**
  * An deallocation expression that is a function call, such as call to `free`.
  */
diff --git a/cpp/ql/src/semmle/code/cpp/models/interfaces/Allocation.qll b/cpp/ql/src/semmle/code/cpp/models/interfaces/Allocation.qll
@@ -91,10 +91,31 @@ abstract class AllocationExpr extends Expr {
  * `new` or `new[]` expressions.  Note that `new` and `new[]` are not function
  * calls, but these functions may also be called directly.
  */
-abstract class OperatorNewAllocationFunction extends AllocationFunction {
+class OperatorNewAllocationFunction extends AllocationFunction {
+  OperatorNewAllocationFunction() {
+    exists(string name |
+      hasGlobalName(name) and
+      (
+        // operator new(bytes, ...)
+        name = "operator new"
+        or
+        // operator new[](bytes, ...)
+        name = "operator new[]"
+      )
+    )
+  }
+
+  override int getSizeArg() { result = 0 }
+
+  override predicate requiresDealloc() { not exists(getPlacementArgument()) }
+
   /**
    * Gets the position of the placement pointer if this is a placement
    * `operator new` function.
    */
-  int getPlacementArgument() { none()}
+  int getPlacementArgument() {
+    getNumberOfParameters() = 2 and
+    getParameter(1).getType() instanceof VoidPointerType and
+    result = 1
+  }
 }
diff --git a/cpp/ql/src/semmle/code/cpp/models/interfaces/Deallocation.qll b/cpp/ql/src/semmle/code/cpp/models/interfaces/Deallocation.qll
@@ -36,5 +36,19 @@ abstract class DeallocationExpr extends Expr {
  * with `delete` or `delete[]` expressions.  Note that `delete` and `delete[]`
  * are not function calls, but these functions may also be called directly.
  */
-abstract class OperatorDeleteDeallocationFunction extends DeallocationFunction {
+class OperatorDeleteDeallocationFunction extends DeallocationFunction {
+  OperatorDeleteDeallocationFunction() {
+    exists(string name |
+      hasGlobalName(name) and
+      (
+        // operator delete(pointer, ...)
+        name = "operator delete"
+        or
+        // operator delete[](pointer, ...)
+        name = "operator delete[]"
+      )
+    )
+  }
+
+  override int getFreedArg() { result = 0 }
 }
