Rename to PlacementNewOperator, move it, and add some docstrings

Author: jeongsoolee09

cpp/common/src/codingstandards/cpp/DynamicMemory.qll

@@ -2,20 +2,6 @@
 
 import cpp
 
-/**
- * An `operator new` or `operator new[]` allocation function called by a placement-new expression.
- *
- * The operator functions have a `std::size_t` as their first parameter and a
- * `void*` parameter somewhere in the rest of the parameter list.
- */
-class PlacementNewOrNewArrayAllocationFunction extends AllocationFunction {
-  PlacementNewOrNewArrayAllocationFunction() {
-    this.getName() in ["operator new", "operator new[]"] and
-    this.getParameter(0).getType().resolveTypedefs*() instanceof Size_t and
-    this.getAParameter().getUnderlyingType() instanceof VoidPointerType
-  }
-}
-
 /**
  * A function that has namespace `std` and has name `allocate` or `deallocate`, including but
  * not limited to:

cpp/common/src/codingstandards/cpp/allocations/CustomOperatorNewDelete.qll

@@ -1,3 +1,10 @@
+/**
+ * Provides classes to help reasoning about `operator new`, `operator new[]`,
+ * `operator delete`, and `operator delete[]`.
+ *
+ * These are described in section [support.dynamic] of the C++ standard.
+ */
+
 import cpp
 import codingstandards.cpp.Handlers
 
@@ -21,6 +28,13 @@ abstract class OperatorNewOrDelete extends Operator {
   }
 }
 
+/**
+ * An `operator new` and `operator new[]` function described in [new.delete.single]
+ * and [new.delete.array], respectively.
+ * 
+ * Note that these do not include [new.delete.placement]. These are captured in
+ * `PlacementOperatorNew`.
+ */
 class ReplaceableOperatorNew extends OperatorNewOrDelete {
   ReplaceableOperatorNew() {
     this.getName().regexpMatch("operator new(\\[\\])?") and
@@ -34,6 +48,10 @@ class ReplaceableOperatorNew extends OperatorNewOrDelete {
   }
 }
 
+/**
+ * `operator new`, `operator new[]`, `operator delete`, or `operator delete[]` functions
+ * that are very likely provided by the user.
+ */
 class CustomOperatorNewOrDelete extends OperatorNewOrDelete {
   CustomOperatorNewOrDelete() {
     this.hasDefinition() and
@@ -62,6 +80,10 @@ class CustomOperatorNewOrDelete extends OperatorNewOrDelete {
 
 class CustomReplaceableOperatorNew extends CustomOperatorNewOrDelete, ReplaceableOperatorNew { }
 
+/**
+ * An `operator delete` or `operator delete[]` deallocation function described in
+ * [new.delete.single] and [new.delete.array], respectively.
+ */
 class ReplaceableOperatorDelete extends OperatorNewOrDelete {
   ReplaceableOperatorDelete() {
     this.getName().regexpMatch("operator delete(\\[\\])?") and
@@ -95,3 +117,18 @@ class CustomReplaceableOperatorDelete extends CustomOperatorNewOrDelete, Replace
     else result.getPartner() = this
   }
 }
+
+/**
+ * An `operator new` or `operator new[]` allocation function called by a placement-new expression,
+ * as described in [new.delete.placement].
+ *
+ * The operator functions have a `std::size_t` as their first parameter and a
+ * `void*` parameter somewhere in the rest of the parameter list.
+ */
+class PlacementOperatorNew extends AllocationFunction {
+  PlacementOperatorNew() {
+    this.getName() in ["operator new", "operator new[]"] and
+    this.getParameter(0).getType().resolveTypedefs*() instanceof Size_t and
+    this.getAParameter().getUnderlyingType() instanceof VoidPointerType
+  }
+}

cpp/misra/src/rules/RULE-21-6-1/DynamicMemoryShouldNotBeUsed.ql

@@ -16,6 +16,7 @@
 import cpp
 import codingstandards.cpp.misra
 import codingstandards.cpp.DynamicMemory
+import codingstandards.cpp.allocations.CustomOperatorNewDelete
 
 /**
  * A function that directly or indirectly allocates dynamic memory.
@@ -32,7 +33,7 @@ abstract class DynamicMemoryAllocatingFunction extends Function { }
 class DirectDynamicMemoryAllocatingFunction extends DynamicMemoryAllocatingFunction {
   DirectDynamicMemoryAllocatingFunction() {
     this instanceof AllocationFunction and
-    not this instanceof PlacementNewOrNewArrayAllocationFunction
+    not this instanceof PlacementOperatorNew
     or
     this.hasGlobalOrStdName("aligned_alloc")
   }

cpp/misra/src/rules/RULE-21-6-2/DynamicMemoryManagedManually.ql

@@ -18,14 +18,15 @@ import cpp
 import codingstandards.cpp.misra
 import codingstandards.cpp.SmartPointers
 import codingstandards.cpp.DynamicMemory
+import codingstandards.cpp.allocations.CustomOperatorNewDelete
 
 class DynamicMemoryManagementFunction extends Function {
   DynamicMemoryManagementFunction() {
     (this instanceof AllocationFunction or this instanceof AlignedAllocFunction) and
     /* Avoid duplicate alerts on `realloc` which is both an `AllocationFunction` and a `DeallocationFunction`. */
     not this instanceof ReallocFunction and
     /* Placement-new expressions are not prohibited by this rule, but by Rule 21.6.3. */
-    not this instanceof PlacementNewOrNewArrayAllocationFunction
+    not this instanceof PlacementOperatorNew
     or
     this instanceof DeallocationFunction and
     /* Avoid duplicate alerts on `realloc` which is both an `AllocationFunction` and a `DeallocationFunction`. */