C++: Impoved alias analysis of smart pointers

cpp/ql/test/library-tests/ir/points_to/points_to.ql

@@ -5,7 +5,16 @@ private import semmle.code.cpp.ir.internal.IntegerConstant as Ints
 private predicate ignoreAllocation(string name) {
   name = "i" or
   name = "p" or
-  name = "q"
+  name = "q" or
+  name = "s" or
+  name = "t" or
+  name = "?{AllAliased}"
+}
+
+private predicate ignoreFile(File file) {
+  // Ignore standard headers.
+  file.getBaseName() = ["memory.h", "type_traits.h", "utility.h"] or
+  not file.fromSource()
 }
 
 module Raw {
@@ -29,7 +38,8 @@ module Raw {
         not ignoreAllocation(memLocation.getAllocation().getAllocationString()) and
         value = memLocation.toString() and
         element = instr.toString() and
-        location = instr.getLocation()
+        location = instr.getLocation() and
+        not ignoreFile(location.getFile())
       )
     }
   }
@@ -52,13 +62,14 @@ module UnaliasedSSA {
     override predicate hasActualResult(Location location, string element, string tag, string value) {
       exists(Instruction instr, MemoryLocation memLocation |
         memLocation = getAMemoryAccess(instr) and
-        not memLocation instanceof AliasedVirtualVariable and
+        not memLocation.getVirtualVariable() instanceof AliasedVirtualVariable and
         not memLocation instanceof AllNonLocalMemory and
         tag = "ussa" and
         not ignoreAllocation(memLocation.getAllocation().getAllocationString()) and
         value = memLocation.toString() and
         element = instr.toString() and
-        location = instr.getLocation()
+        location = instr.getLocation() and
+        not ignoreFile(location.getFile())
       )
     }
   }

cpp/ql/test/library-tests/ir/points_to/smart_pointer.cpp

@@ -0,0 +1,33 @@
+#include "../../../include/memory.h"
+#include "../../../include/utility.h"
+
+using std::shared_ptr;
+using std::unique_ptr;
+
+struct S {
+    int x;
+};
+
+void unique_ptr_init(S s) {
+    unique_ptr<S> p(new S); //$ussa=dynamic{1}
+    int i = (*p).x; //$ussa=dynamic{1}[0..4)<int>
+    *p = s;  //$ussa=dynamic{1}[0..4)<S>
+    unique_ptr<S> q = std::move(p);
+    *(q.get()) = s;  //$ussa=dynamic{1}[0..4)<S>
+    shared_ptr<S> t(std::move(q));
+    t->x = 5; //$ussa=dynamic{1}[0..4)<int>
+    *t = s; //$ussa=dynamic{1}[0..4)<S>
+    *(t.get()) = s; //$ussa=dynamic{1}[0..4)<S>
+}
+
+void shared_ptr_init(S s) {
+    shared_ptr<S> p(new S); //$ussa=dynamic{1}
+    int i = (*p).x; //$ussa=dynamic{1}[0..4)<int>
+    *p = s;  //$ussa=dynamic{1}[0..4)<S>
+    shared_ptr<S> q = std::move(p);
+    *(q.get()) = s;  //$ussa=dynamic{1}[0..4)<S>
+    shared_ptr<S> t(q);
+    t->x = 5; //$ussa=dynamic{1}[0..4)<int>
+    *t = s; //$ussa=dynamic{1}[0..4)<S>
+    *(t.get()) = s; //$ussa=dynamic{1}[0..4)<S>
+}