C++: Fix off-by-one error in getType on 'FinalGlobalValue' nodes and accept test changes.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll

@@ -795,7 +795,7 @@ class FinalGlobalValue extends Node, TFinalGlobalValue {
   override DataFlowType getType() {
     exists(int indirectionIndex |
       indirectionIndex = globalUse.getIndirectionIndex() and
-      result = getTypeImpl(globalUse.getUnderlyingType(), indirectionIndex - 1)
+      result = getTypeImpl(globalUse.getUnderlyingType(), indirectionIndex)
     )
   }
 

cpp/ql/test/library-tests/dataflow/dataflow-tests/dispatch.cpp

@@ -52,10 +52,10 @@ Top *readGlobalBottom() {
 }
 
 void DispatchThroughGlobal() {
-  sink(globalBottom->isSource1()); // $ MISSING: ast,ir
+  sink(globalBottom->isSource1()); // $ ir MISSING: ast
   sink(globalMiddle->isSource1()); // no flow
 
-  sink(readGlobalBottom()->isSource1()); // $ MISSING: ast,ir
+  sink(readGlobalBottom()->isSource1()); // $ ir MISSING: ast
 
   globalBottom = new Bottom();
   globalMiddle = new Middle();

cpp/ql/test/library-tests/dataflow/dataflow-tests/test-source-sink.expected

@@ -173,6 +173,8 @@ irFlow
 | dispatch.cpp:16:37:16:42 | call to source | dispatch.cpp:40:15:40:23 | call to isSource2 |
 | dispatch.cpp:22:37:22:42 | call to source | dispatch.cpp:31:16:31:24 | call to isSource1 |
 | dispatch.cpp:22:37:22:42 | call to source | dispatch.cpp:39:15:39:23 | call to isSource1 |
+| dispatch.cpp:22:37:22:42 | call to source | dispatch.cpp:55:22:55:30 | call to isSource1 |
+| dispatch.cpp:22:37:22:42 | call to source | dispatch.cpp:58:28:58:36 | call to isSource1 |
 | dispatch.cpp:33:18:33:23 | call to source | dispatch.cpp:23:38:23:38 | x |
 | dispatch.cpp:41:17:41:22 | call to source | dispatch.cpp:23:38:23:38 | x |
 | dispatch.cpp:69:15:69:20 | call to source | dispatch.cpp:23:38:23:38 | x |

cpp/ql/test/library-tests/dataflow/dispatch/test.cpp

@@ -109,7 +109,7 @@ void set_global_to_derived() {
 }
 
 void read_global() {
-  global_derived->virtual_f(); // $ SPURIOUS: target=3 MISSING: target=8
+  global_derived->virtual_f(); // $ target=8
 }
 
 Base* global_base_or_derived;
@@ -123,5 +123,5 @@ void set_global_base_or_derived_2() {
 }
 
 void read_global_base_or_derived() {
-  global_base_or_derived->virtual_f(); // $ target=3 MISSING: target=8
+  global_base_or_derived->virtual_f(); // $ target=3 target=8
 }