fix ThisArgumentOperand location

The correct check to do to choose between using `getAnyDef` and `getUse`
is to check whether the location is an instance of UknonwnLocation.

Author: redsun82

cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/Operand.qll

@@ -416,10 +416,9 @@ class ThisArgumentOperand extends ArgumentOperand {
   // in most cases the def location makes more sense, but in some corner cases it
   // does not have a location: in those cases we fall back to the use location
   override Language::Location getLocation() {
-    result = this.getAnyDef().getLocation()
-    or
-    not exists(this.getAnyDef().getLocation()) and
-    result = this.getUse().getLocation()
+    if not this.getAnyDef().getLocation() instanceof Language::UnknownLocation
+    then result = this.getAnyDef().getLocation()
+    else result = this.getUse().getLocation()
   }
 }
 

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/Operand.qll

@@ -416,10 +416,9 @@ class ThisArgumentOperand extends ArgumentOperand {
   // in most cases the def location makes more sense, but in some corner cases it
   // does not have a location: in those cases we fall back to the use location
   override Language::Location getLocation() {
-    result = this.getAnyDef().getLocation()
-    or
-    not exists(this.getAnyDef().getLocation()) and
-    result = this.getUse().getLocation()
+    if not this.getAnyDef().getLocation() instanceof Language::UnknownLocation
+    then result = this.getAnyDef().getLocation()
+    else result = this.getUse().getLocation()
   }
 }
 

cpp/ql/lib/semmle/code/cpp/ir/implementation/unaliased_ssa/Operand.qll

@@ -416,10 +416,9 @@ class ThisArgumentOperand extends ArgumentOperand {
   // in most cases the def location makes more sense, but in some corner cases it
   // does not have a location: in those cases we fall back to the use location
   override Language::Location getLocation() {
-    result = this.getAnyDef().getLocation()
-    or
-    not exists(this.getAnyDef().getLocation()) and
-    result = this.getUse().getLocation()
+    if not this.getAnyDef().getLocation() instanceof Language::UnknownLocation
+    then result = this.getAnyDef().getLocation()
+    else result = this.getUse().getLocation()
   }
 }
 

cpp/ql/test/library-tests/ir/ir/operand_locations.expected

@@ -671,18 +671,6 @@
 | file://:0:0:0:0 | Arg(0) | 0:r0_8 |
 | file://:0:0:0:0 | Arg(0) | 0:r0_15 |
 | file://:0:0:0:0 | Arg(0) | 0:r0_15 |
-| file://:0:0:0:0 | Arg(this) | this:r0_1 |
-| file://:0:0:0:0 | Arg(this) | this:r0_1 |
-| file://:0:0:0:0 | Arg(this) | this:r0_3 |
-| file://:0:0:0:0 | Arg(this) | this:r0_5 |
-| file://:0:0:0:0 | Arg(this) | this:r0_5 |
-| file://:0:0:0:0 | Arg(this) | this:r0_5 |
-| file://:0:0:0:0 | Arg(this) | this:r0_7 |
-| file://:0:0:0:0 | Arg(this) | this:r0_9 |
-| file://:0:0:0:0 | Arg(this) | this:r0_11 |
-| file://:0:0:0:0 | Arg(this) | this:r0_11 |
-| file://:0:0:0:0 | Arg(this) | this:r0_13 |
-| file://:0:0:0:0 | Arg(this) | this:r0_15 |
 | file://:0:0:0:0 | CallTarget | func:r0_1 |
 | file://:0:0:0:0 | ChiPartial | partial:m0_2 |
 | file://:0:0:0:0 | ChiPartial | partial:m0_3 |
@@ -3265,6 +3253,7 @@
 | ir.cpp:754:8:754:8 | Address | &:r754_22 |
 | ir.cpp:754:8:754:8 | Address | &:r754_24 |
 | ir.cpp:754:8:754:8 | Address | &:r754_34 |
+| ir.cpp:754:8:754:8 | Arg(this) | this:r0_5 |
 | ir.cpp:754:8:754:8 | Arg(this) | this:r754_22 |
 | ir.cpp:754:8:754:8 | CallTarget | func:r754_11 |
 | ir.cpp:754:8:754:8 | CallTarget | func:r754_23 |
@@ -3356,6 +3345,7 @@
 | ir.cpp:763:8:763:8 | Address | &:r763_22 |
 | ir.cpp:763:8:763:8 | Address | &:r763_24 |
 | ir.cpp:763:8:763:8 | Address | &:r763_34 |
+| ir.cpp:763:8:763:8 | Arg(this) | this:r0_5 |
 | ir.cpp:763:8:763:8 | Arg(this) | this:r763_22 |
 | ir.cpp:763:8:763:8 | CallTarget | func:r763_11 |
 | ir.cpp:763:8:763:8 | CallTarget | func:r763_23 |
@@ -5166,6 +5156,10 @@
 | ir.cpp:1078:18:1078:18 | Address | &:r1078_42 |
 | ir.cpp:1078:18:1078:18 | Address | &:r1078_42 |
 | ir.cpp:1078:18:1078:18 | Arg(0) | 0:r1078_28 |
+| ir.cpp:1078:18:1078:18 | Arg(this) | this:r0_1 |
+| ir.cpp:1078:18:1078:18 | Arg(this) | this:r0_3 |
+| ir.cpp:1078:18:1078:18 | Arg(this) | this:r0_5 |
+| ir.cpp:1078:18:1078:18 | Arg(this) | this:r0_7 |
 | ir.cpp:1078:18:1078:18 | Arg(this) | this:r1078_42 |
 | ir.cpp:1078:18:1078:18 | CallTarget | func:r1078_10 |
 | ir.cpp:1078:18:1078:18 | CallTarget | func:r1078_18 |
@@ -5227,6 +5221,10 @@
 | ir.cpp:1084:25:1084:25 | Address | &:r1084_33 |
 | ir.cpp:1084:25:1084:25 | Address | &:r1084_33 |
 | ir.cpp:1084:25:1084:25 | Arg(0) | 0:r1084_28 |
+| ir.cpp:1084:25:1084:25 | Arg(this) | this:r0_9 |
+| ir.cpp:1084:25:1084:25 | Arg(this) | this:r0_11 |
+| ir.cpp:1084:25:1084:25 | Arg(this) | this:r0_13 |
+| ir.cpp:1084:25:1084:25 | Arg(this) | this:r0_15 |
 | ir.cpp:1084:25:1084:25 | Arg(this) | this:r1084_33 |
 | ir.cpp:1084:25:1084:25 | CallTarget | func:r1084_10 |
 | ir.cpp:1084:25:1084:25 | CallTarget | func:r1084_18 |
@@ -6622,6 +6620,7 @@
 | ir.cpp:1447:16:1447:39 | ChiTotal | total:m1446_5 |
 | ir.cpp:1447:16:1447:39 | SideEffect | ~m1446_5 |
 | ir.cpp:1447:16:1447:39 | StoreValue | r1447_3 |
+| ir.cpp:1447:44:1447:44 | Arg(this) | this:r0_11 |
 | ir.cpp:1447:44:1447:44 | CallTarget | func:r1447_7 |
 | ir.cpp:1447:44:1447:44 | ChiPartial | partial:m1447_9 |
 | ir.cpp:1447:44:1447:44 | ChiTotal | total:m1447_5 |

cpp/ql/test/library-tests/syntax-zoo/dataflow-ir-consistency.expected

@@ -1613,6 +1613,8 @@ postWithInFlow
 | cpp11.cpp:28:21:28:21 | (__begin) [post update] | PostUpdateNode should not be the target of local flow. |
 | cpp11.cpp:28:21:28:21 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
 | cpp11.cpp:28:21:28:21 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
+| cpp11.cpp:28:21:28:21 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
+| cpp11.cpp:28:21:28:21 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
 | cpp11.cpp:28:21:28:21 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | cpp11.cpp:28:21:28:21 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | cpp11.cpp:28:21:28:34 | temporary object [post update] | PostUpdateNode should not be the target of local flow. |
@@ -1689,10 +1691,6 @@ postWithInFlow
 | fieldaccess.cpp:9:2:9:2 | i [post update] | PostUpdateNode should not be the target of local flow. |
 | file://:0:0:0:0 | (Base *)... [post update] | PostUpdateNode should not be the target of local flow. |
 | file://:0:0:0:0 | (Middle *)... [post update] | PostUpdateNode should not be the target of local flow. |
-| file://:0:0:0:0 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
-| file://:0:0:0:0 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
-| file://:0:0:0:0 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
-| file://:0:0:0:0 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
 | file://:0:0:0:0 | (reference dereference) [post update] | PostUpdateNode should not be the target of local flow. |
 | file://:0:0:0:0 | (reference dereference) [post update] | PostUpdateNode should not be the target of local flow. |
 | file://:0:0:0:0 | (reference dereference) [post update] | PostUpdateNode should not be the target of local flow. |
@@ -1704,8 +1702,6 @@ postWithInFlow
 | file://:0:0:0:0 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | file://:0:0:0:0 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | file://:0:0:0:0 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
-| file://:0:0:0:0 | this [post update] | PostUpdateNode should not be the target of local flow. |
-| file://:0:0:0:0 | this [post update] | PostUpdateNode should not be the target of local flow. |
 | forstmt.cpp:2:14:2:14 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | forstmt.cpp:2:29:2:29 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | forstmt.cpp:9:14:9:14 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
@@ -2067,6 +2063,7 @@ postWithInFlow
 | ir.cpp:754:8:754:8 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:754:8:754:8 | middle_s [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:754:8:754:8 | this [post update] | PostUpdateNode should not be the target of local flow. |
+| ir.cpp:754:8:754:8 | this [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:757:3:757:8 | this [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:757:12:757:12 | Argument this [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:757:12:757:12 | Argument this [post update] | PostUpdateNode should not be the target of local flow. |
@@ -2078,6 +2075,7 @@ postWithInFlow
 | ir.cpp:763:8:763:8 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:763:8:763:8 | derived_s [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:763:8:763:8 | this [post update] | PostUpdateNode should not be the target of local flow. |
+| ir.cpp:763:8:763:8 | this [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:766:3:766:9 | this [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:766:13:766:13 | Argument this [post update] | PostUpdateNode should not be the target of local flow. |
 | ir.cpp:766:13:766:13 | Argument this [post update] | PostUpdateNode should not be the target of local flow. |
@@ -2642,6 +2640,8 @@ postWithInFlow
 | stream_it.cpp:11:10:11:12 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | stream_it.cpp:11:16:11:16 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
 | stream_it.cpp:11:16:11:16 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
+| stream_it.cpp:11:16:11:16 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
+| stream_it.cpp:11:16:11:16 | (__range) [post update] | PostUpdateNode should not be the target of local flow. |
 | stream_it.cpp:11:16:11:16 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | stream_it.cpp:11:16:11:16 | VariableAddress [post update] | PostUpdateNode should not be the target of local flow. |
 | stream_it.cpp:19:13:19:14 | (reference to) [post update] | PostUpdateNode should not be the target of local flow. |

csharp/ql/src/experimental/ir/implementation/raw/Operand.qll

@@ -416,10 +416,9 @@ class ThisArgumentOperand extends ArgumentOperand {
   // in most cases the def location makes more sense, but in some corner cases it
   // does not have a location: in those cases we fall back to the use location
   override Language::Location getLocation() {
-    result = this.getAnyDef().getLocation()
-    or
-    not exists(this.getAnyDef().getLocation()) and
-    result = this.getUse().getLocation()
+    if not this.getAnyDef().getLocation() instanceof Language::UnknownLocation
+    then result = this.getAnyDef().getLocation()
+    else result = this.getUse().getLocation()
   }
 }
 

csharp/ql/src/experimental/ir/implementation/unaliased_ssa/Operand.qll

@@ -416,10 +416,9 @@ class ThisArgumentOperand extends ArgumentOperand {
   // in most cases the def location makes more sense, but in some corner cases it
   // does not have a location: in those cases we fall back to the use location
   override Language::Location getLocation() {
-    result = this.getAnyDef().getLocation()
-    or
-    not exists(this.getAnyDef().getLocation()) and
-    result = this.getUse().getLocation()
+    if not this.getAnyDef().getLocation() instanceof Language::UnknownLocation
+    then result = this.getAnyDef().getLocation()
+    else result = this.getUse().getLocation()
   }
 }