C++: Add {AllAliased} side effects for smart pointers

Dave Bartolomeo · Dave Bartolomeo · commit 5d0a4cae90e0 · 2021-04-22T16:51:36.000-04:00
Smart pointer constructors, assignments, and `reset()` can actually have fairly large side effects, especially with custom deleters, destructors for objects being destroyed, and so on. I've re-introduced `{AllAliased}` side effects for these functions. There was no immediate effect on analysis results.
diff --git a/cpp/ql/src/semmle/code/cpp/models/implementations/SmartPointer.qll b/cpp/ql/src/semmle/code/cpp/models/implementations/SmartPointer.qll
@@ -106,9 +106,9 @@ private class SmartPtrSetterFunction extends MemberFunction, AliasFunction, Side
     )
   }
 
-  override predicate hasOnlySpecificReadSideEffects() { this instanceof Constructor }
+  override predicate hasOnlySpecificReadSideEffects() { none() }
 
-  override predicate hasOnlySpecificWriteSideEffects() { this instanceof ConstMemberFunction }
+  override predicate hasOnlySpecificWriteSideEffects() { none() }
 
   override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
     // Always write to the destination smart pointer itself.

Original file line number	Diff line number	Diff line change
`@@ -106,9 +106,9 @@ private class SmartPtrSetterFunction extends MemberFunction, AliasFunction, Side`
`106`	`106`	`)`
`107`	`107`	`}`
`108`	`108`
`109`		`- override predicate hasOnlySpecificReadSideEffects() { this instanceof Constructor }`
	`109`	`+ override predicate hasOnlySpecificReadSideEffects() { none() }`
`110`	`110`
`111`		`- override predicate hasOnlySpecificWriteSideEffects() { this instanceof ConstMemberFunction }`
	`111`	`+ override predicate hasOnlySpecificWriteSideEffects() { none() }`
`112`	`112`
`113`	`113`	`override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {`
`114`	`114`	`// Always write to the destination smart pointer itself.`