Merge pull request #2017 from AndreiDiaconu1/ircsharp-various

C# IR: Some minor additions

csharp/ql/src/semmle/code/csharp/ir/implementation/raw/internal/TranslatedElement.qll

@@ -99,6 +99,12 @@ private predicate ignoreExprOnly(Expr expr) {
   // Ignore the expression (that is not a declaration)
   // that appears in a using block
   expr.getParent().(UsingBlockStmt).getExpr() = expr
+  or
+  // Ignore the `ThisAccess` when it is used as the qualifier for
+  // a callable access (e.g. when a member callable is passed as a
+  // parameter for a delegate creation expression)
+  expr instanceof ThisAccess and
+  expr.getParent() instanceof CallableAccess
 }
 
 /**
@@ -199,6 +205,10 @@ private predicate ignoreLoad(Expr expr) {
   // to get the address of the first element in an array
   expr = any(ArrayAccess aa).getQualifier()
   or
+  // Indexer calls returns a reference or a value,
+  // no need to load it
+  expr instanceof IndexerCall
+  or
   // No load is needed for the lvalue in an assignment such as:
   // Eg. `Object obj = oldObj`;
   expr = any(Assignment a).getLValue() and

csharp/ql/src/semmle/code/csharp/ir/implementation/raw/internal/TranslatedExpr.qll

@@ -1382,6 +1382,11 @@ class TranslatedAssignExpr extends TranslatedAssignment {
 class TranslatedAssignOperation extends TranslatedAssignment {
   override AssignOperation expr;
 
+  TranslatedAssignOperation() {
+    // Assignments to events is handled differently
+    not expr.getLValue() instanceof EventAccess
+  }
+
   override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) {
     kind instanceof GotoEdge and
     (
@@ -1893,104 +1898,6 @@ class TranslatedIsExpr extends TranslatedNonConstantExpr {
   }
 }
 
-/**
- * The IR translation of a lambda expression. This initializes a temporary variable whose type is that of the lambda,
- * using the initializer list that represents the captures of the lambda.
- */
-class TranslatedLambdaExpr extends TranslatedNonConstantExpr, InitializationContext {
-  override LambdaExpr expr;
-
-  final override Instruction getFirstInstruction() {
-    result = this.getInstruction(InitializerVariableAddressTag())
-  }
-
-  final override TranslatedElement getChild(int id) { id = 0 and result = this.getInitialization() }
-
-  override Instruction getResult() { result = this.getInstruction(LoadTag()) }
-
-  override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) {
-    tag = InitializerVariableAddressTag() and
-    kind instanceof GotoEdge and
-    result = this.getInstruction(InitializerStoreTag())
-    or
-    tag = InitializerStoreTag() and
-    kind instanceof GotoEdge and
-    (
-      result = this.getInitialization().getFirstInstruction()
-      or
-      not this.hasInitializer() and result = this.getInstruction(LoadTag())
-    )
-    or
-    tag = LoadTag() and
-    kind instanceof GotoEdge and
-    result = this.getParent().getChildSuccessor(this)
-  }
-
-  override Instruction getChildSuccessor(TranslatedElement child) {
-    child = getInitialization() and
-    result = this.getInstruction(LoadTag())
-  }
-
-  override predicate hasInstruction(
-    Opcode opcode, InstructionTag tag, Type resultType, boolean isLValue
-  ) {
-    tag = InitializerVariableAddressTag() and
-    opcode instanceof Opcode::VariableAddress and
-    resultType = this.getResultType() and
-    isLValue = true
-    or
-    tag = InitializerStoreTag() and
-    opcode instanceof Opcode::Uninitialized and
-    resultType = this.getResultType() and
-    isLValue = false
-    or
-    tag = LoadTag() and
-    opcode instanceof Opcode::Load and
-    resultType = this.getResultType() and
-    isLValue = false
-  }
-
-  override Instruction getInstructionOperand(InstructionTag tag, OperandTag operandTag) {
-    tag = InitializerStoreTag() and
-    operandTag instanceof AddressOperandTag and
-    result = this.getInstruction(InitializerVariableAddressTag())
-    or
-    tag = LoadTag() and
-    (
-      operandTag instanceof AddressOperandTag and
-      result = this.getInstruction(InitializerVariableAddressTag())
-      or
-      operandTag instanceof LoadOperandTag and
-      result = this.getEnclosingFunction().getUnmodeledDefinitionInstruction()
-    )
-  }
-
-  override IRVariable getInstructionVariable(InstructionTag tag) {
-    (
-      tag = InitializerVariableAddressTag() or
-      tag = InitializerStoreTag()
-    ) and
-    result = this.getTempVariable(LambdaTempVar())
-  }
-
-  override predicate hasTempVariable(TempVariableTag tag, Type type) {
-    tag = LambdaTempVar() and
-    type = this.getResultType()
-  }
-
-  final override Instruction getTargetAddress() {
-    result = this.getInstruction(InitializerVariableAddressTag())
-  }
-
-  final override Type getTargetType() { result = this.getResultType() }
-
-  private predicate hasInitializer() { exists(this.getInitialization()) }
-
-  private TranslatedInitialization getInitialization() {
-    result = getTranslatedInitialization(expr.getChild(0))
-  }
-}
-
 /**
  * The translation of a `DelegateCall`. Since this type of call needs
  * desugaring, we treat it as a special case. The AST node of the
@@ -2155,3 +2062,37 @@ class TranslatedDelegateCreation extends TranslatedCreation {
 
   override predicate needsLoad() { none() }
 }
+
+/**
+ * Represents the IR translation of an assign operation where the lhs is an event access.
+ */
+class TranslatedEventAccess extends TranslatedNonConstantExpr {
+  override AssignOperation expr;
+
+  TranslatedEventAccess() { expr.getLValue() instanceof EventAccess }
+
+  // We only translate the lhs, since the rhs is translated as part of the
+  // accessor call.
+  override TranslatedElement getChild(int id) { id = 0 and result = this.getLValue() }
+
+  override predicate hasInstruction(
+    Opcode opcode, InstructionTag tag, Type resultType, boolean isLValue
+  ) {
+    none()
+  }
+
+  final override Instruction getFirstInstruction() {
+    result = this.getLValue().getFirstInstruction()
+  }
+
+  override Instruction getResult() { none() }
+
+  override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) { none() }
+
+  override Instruction getChildSuccessor(TranslatedElement child) {
+    child = this.getLValue() and
+    result = this.getParent().getChildSuccessor(this)
+  }
+
+  private TranslatedExpr getLValue() { result = getTranslatedExpr(expr.getLValue()) }
+}

csharp/ql/test/library-tests/ir/ir/events.cs

@@ -0,0 +1,35 @@
+class Events
+{
+    public delegate string MyDel(string str);
+    public MyDel Inst;
+
+    event MyDel MyEvent;
+
+    public Events()
+    {
+        this.Inst = new MyDel(this.Fun);
+    }
+
+    public void AddEvent() 
+    {
+        this.MyEvent += this.Inst;
+    }
+
+    public void RemoveEvent()
+    {
+        this.MyEvent -= this.Inst;
+    }
+
+    public string Fun(string str) 
+    {
+        return str;
+    }
+    
+    static void Main(string[] args) 
+    {
+        Events obj = new Events();
+        obj.AddEvent();
+        string result = obj.MyEvent("string");
+        obj.RemoveEvent();
+    }
+}

csharp/ql/test/library-tests/ir/ir/indexers.cs

@@ -0,0 +1,30 @@
+class Indexers
+{
+    public class MyClass
+    {
+        public MyClass()
+        {
+        }
+
+        private string[] address = new string[2];
+        public string this[int index]
+        {
+            get
+            {
+                return address[index];
+            }
+            set
+            {
+                address[index] = value;
+            }
+        }
+    }
+
+    public static void Main()
+    {
+        MyClass inst = new MyClass();
+        inst[0] = "str1";
+        inst[1] = "str1";
+        inst[1] = inst[0];
+    }
+}

csharp/ql/test/library-tests/ir/ir/raw_ir.expected

@@ -480,6 +480,111 @@ delegates.cs:
 #   11|     v0_17(Void)        = UnmodeledUse             : mu*
 #   11|     v0_18(Void)        = ExitFunction             : 
 
+events.cs:
+#    8| System.Void Events..ctor()
+#    8|   Block 0
+#    8|     v0_0(Void)          = EnterFunction          : 
+#    8|     mu0_1(null)         = AliasedDefinition      : 
+#    8|     mu0_2(null)         = UnmodeledDefinition    : 
+#    8|     r0_3(glval<Events>) = InitializeThis         : 
+#   10|     r0_4(MyDel)         = NewObj                 : 
+#   10|     r0_5(glval<null>)   = FunctionAddress[MyDel] : 
+#   10|     r0_6(glval<MyDel>)  = FunctionAddress[Fun]   : 
+#   10|     v0_7(Void)          = Call                   : func:r0_5, this:r0_4, 0:r0_6
+#   10|     mu0_8(null)         = ^CallSideEffect        : ~mu0_2
+#   10|     r0_9(Events)        = CopyValue              : r0_3
+#   10|     r0_10(glval<MyDel>) = FieldAddress[Inst]     : r0_9
+#   10|     mu0_11(MyDel)       = Store                  : &:r0_10, r0_4
+#    8|     v0_12(Void)         = ReturnVoid             : 
+#    8|     v0_13(Void)         = UnmodeledUse           : mu*
+#    8|     v0_14(Void)         = ExitFunction           : 
+
+#   13| System.Void Events.AddEvent()
+#   13|   Block 0
+#   13|     v0_0(Void)          = EnterFunction                : 
+#   13|     mu0_1(null)         = AliasedDefinition            : 
+#   13|     mu0_2(null)         = UnmodeledDefinition          : 
+#   13|     r0_3(glval<Events>) = InitializeThis               : 
+#   15|     r0_4(Events)        = CopyValue                    : r0_3
+#   15|     r0_5(glval<null>)   = FunctionAddress[add_MyEvent] : 
+#   15|     r0_6(Events)        = CopyValue                    : r0_3
+#   15|     r0_7(glval<MyDel>)  = FieldAddress[Inst]           : r0_6
+#   15|     r0_8(MyDel)         = Load                         : &:r0_7, ~mu0_2
+#   15|     v0_9(Void)          = Call                         : func:r0_5, this:r0_4, 0:r0_8
+#   15|     mu0_10(null)        = ^CallSideEffect              : ~mu0_2
+#   13|     v0_11(Void)         = ReturnVoid                   : 
+#   13|     v0_12(Void)         = UnmodeledUse                 : mu*
+#   13|     v0_13(Void)         = ExitFunction                 : 
+
+#   18| System.Void Events.RemoveEvent()
+#   18|   Block 0
+#   18|     v0_0(Void)          = EnterFunction                   : 
+#   18|     mu0_1(null)         = AliasedDefinition               : 
+#   18|     mu0_2(null)         = UnmodeledDefinition             : 
+#   18|     r0_3(glval<Events>) = InitializeThis                  : 
+#   20|     r0_4(Events)        = CopyValue                       : r0_3
+#   20|     r0_5(glval<null>)   = FunctionAddress[remove_MyEvent] : 
+#   20|     r0_6(Events)        = CopyValue                       : r0_3
+#   20|     r0_7(glval<MyDel>)  = FieldAddress[Inst]              : r0_6
+#   20|     r0_8(MyDel)         = Load                            : &:r0_7, ~mu0_2
+#   20|     v0_9(Void)          = Call                            : func:r0_5, this:r0_4, 0:r0_8
+#   20|     mu0_10(null)        = ^CallSideEffect                 : ~mu0_2
+#   18|     v0_11(Void)         = ReturnVoid                      : 
+#   18|     v0_12(Void)         = UnmodeledUse                    : mu*
+#   18|     v0_13(Void)         = ExitFunction                    : 
+
+#   23| System.String Events.Fun(System.String)
+#   23|   Block 0
+#   23|     v0_0(Void)           = EnterFunction            : 
+#   23|     mu0_1(null)          = AliasedDefinition        : 
+#   23|     mu0_2(null)          = UnmodeledDefinition      : 
+#   23|     r0_3(glval<Events>)  = InitializeThis           : 
+#   23|     r0_4(glval<String>)  = VariableAddress[str]     : 
+#   23|     mu0_5(String)        = InitializeParameter[str] : &:r0_4
+#   25|     r0_6(glval<String>)  = VariableAddress[#return] : 
+#   25|     r0_7(glval<String>)  = VariableAddress[str]     : 
+#   25|     r0_8(String)         = Load                     : &:r0_7, ~mu0_2
+#   25|     mu0_9(String)        = Store                    : &:r0_6, r0_8
+#   23|     r0_10(glval<String>) = VariableAddress[#return] : 
+#   23|     v0_11(Void)          = ReturnValue              : &:r0_10, ~mu0_2
+#   23|     v0_12(Void)          = UnmodeledUse             : mu*
+#   23|     v0_13(Void)          = ExitFunction             : 
+
+#   28| System.Void Events.Main(System.String[])
+#   28|   Block 0
+#   28|     v0_0(Void)            = EnterFunction                : 
+#   28|     mu0_1(null)           = AliasedDefinition            : 
+#   28|     mu0_2(null)           = UnmodeledDefinition          : 
+#   28|     r0_3(glval<String[]>) = VariableAddress[args]        : 
+#   28|     mu0_4(String[])       = InitializeParameter[args]    : &:r0_3
+#   30|     r0_5(glval<Events>)   = VariableAddress[obj]         : 
+#   30|     r0_6(Events)          = NewObj                       : 
+#   30|     r0_7(glval<null>)     = FunctionAddress[Events]      : 
+#   30|     v0_8(Void)            = Call                         : func:r0_7, this:r0_6
+#   30|     mu0_9(null)           = ^CallSideEffect              : ~mu0_2
+#   30|     mu0_10(Events)        = Store                        : &:r0_5, r0_6
+#   31|     r0_11(glval<Events>)  = VariableAddress[obj]         : 
+#   31|     r0_12(Events)         = Load                         : &:r0_11, ~mu0_2
+#   31|     r0_13(glval<null>)    = FunctionAddress[AddEvent]    : 
+#   31|     v0_14(Void)           = Call                         : func:r0_13, this:r0_12
+#   31|     mu0_15(null)          = ^CallSideEffect              : ~mu0_2
+#   32|     r0_16(glval<String>)  = VariableAddress[result]      : 
+#   32|     r0_17(glval<Events>)  = VariableAddress[obj]         : 
+#   32|     r0_18(Events)         = Load                         : &:r0_17, ~mu0_2
+#   32|     r0_19(glval<null>)    = FunctionAddress[Invoke]      : 
+#   32|     r0_20(String)         = StringConstant["string"]     : 
+#   32|     v0_21(Void)           = Call                         : func:r0_19, this:r0_18, 0:r0_20
+#   32|     mu0_22(null)          = ^CallSideEffect              : ~mu0_2
+#   32|     mu0_23(String)        = Store                        : &:r0_16, v0_21
+#   33|     r0_24(glval<Events>)  = VariableAddress[obj]         : 
+#   33|     r0_25(Events)         = Load                         : &:r0_24, ~mu0_2
+#   33|     r0_26(glval<null>)    = FunctionAddress[RemoveEvent] : 
+#   33|     v0_27(Void)           = Call                         : func:r0_26, this:r0_25
+#   33|     mu0_28(null)          = ^CallSideEffect              : ~mu0_2
+#   28|     v0_29(Void)           = ReturnVoid                   : 
+#   28|     v0_30(Void)           = UnmodeledUse                 : mu*
+#   28|     v0_31(Void)           = ExitFunction                 : 
+
 foreach.cs:
 #    4| System.Void ForEach.Main()
 #    4|   Block 0
@@ -598,6 +703,104 @@ func_with_param_call.cs:
 #   10|     v0_12(Void)         = UnmodeledUse             : mu*
 #   10|     v0_13(Void)         = ExitFunction             : 
 
+indexers.cs:
+#    5| System.Void Indexers.MyClass..ctor()
+#    5|   Block 0
+#    5|     v0_0(Void)           = EnterFunction       : 
+#    5|     mu0_1(null)          = AliasedDefinition   : 
+#    5|     mu0_2(null)          = UnmodeledDefinition : 
+#    5|     r0_3(glval<MyClass>) = InitializeThis      : 
+#    6|     v0_4(Void)           = NoOp                : 
+#    5|     v0_5(Void)           = ReturnVoid          : 
+#    5|     v0_6(Void)           = UnmodeledUse        : mu*
+#    5|     v0_7(Void)           = ExitFunction        : 
+
+#   12| System.String Indexers.MyClass.get_Item(System.Int32)
+#   12|   Block 0
+#   12|     v0_0(Void)            = EnterFunction              : 
+#   12|     mu0_1(null)           = AliasedDefinition          : 
+#   12|     mu0_2(null)           = UnmodeledDefinition        : 
+#   12|     r0_3(glval<MyClass>)  = InitializeThis             : 
+#   10|     r0_4(glval<Int32>)    = VariableAddress[index]     : 
+#   10|     mu0_5(Int32)          = InitializeParameter[index] : &:r0_4
+#   14|     r0_6(glval<String>)   = VariableAddress[#return]   : 
+#   14|     r0_7(MyClass)         = CopyValue                  : r0_3
+#   14|     r0_8(glval<String[]>) = FieldAddress[address]      : r0_7
+#   14|     r0_9(String[])        = ElementsAddress            : r0_8
+#   14|     r0_10(glval<Int32>)   = VariableAddress[index]     : 
+#   14|     r0_11(Int32)          = Load                       : &:r0_10, ~mu0_2
+#   14|     r0_12(String[])       = PointerAdd[8]              : r0_9, r0_11
+#   14|     r0_13(String)         = Load                       : &:r0_12, ~mu0_2
+#   14|     mu0_14(String)        = Store                      : &:r0_6, r0_13
+#   12|     r0_15(glval<String>)  = VariableAddress[#return]   : 
+#   12|     v0_16(Void)           = ReturnValue                : &:r0_15, ~mu0_2
+#   12|     v0_17(Void)           = UnmodeledUse               : mu*
+#   12|     v0_18(Void)           = ExitFunction               : 
+
+#   16| System.Void Indexers.MyClass.set_Item(System.Int32,System.String)
+#   16|   Block 0
+#   16|     v0_0(Void)             = EnterFunction              : 
+#   16|     mu0_1(null)            = AliasedDefinition          : 
+#   16|     mu0_2(null)            = UnmodeledDefinition        : 
+#   16|     r0_3(glval<MyClass>)   = InitializeThis             : 
+#   10|     r0_4(glval<Int32>)     = VariableAddress[index]     : 
+#   10|     mu0_5(Int32)           = InitializeParameter[index] : &:r0_4
+#   16|     r0_6(glval<String>)    = VariableAddress[value]     : 
+#   16|     mu0_7(String)          = InitializeParameter[value] : &:r0_6
+#   18|     r0_8(glval<String>)    = VariableAddress[value]     : 
+#   18|     r0_9(String)           = Load                       : &:r0_8, ~mu0_2
+#   18|     r0_10(MyClass)         = CopyValue                  : r0_3
+#   18|     r0_11(glval<String[]>) = FieldAddress[address]      : r0_10
+#   18|     r0_12(String[])        = ElementsAddress            : r0_11
+#   18|     r0_13(glval<Int32>)    = VariableAddress[index]     : 
+#   18|     r0_14(Int32)           = Load                       : &:r0_13, ~mu0_2
+#   18|     r0_15(String[])        = PointerAdd[8]              : r0_12, r0_14
+#   18|     mu0_16(String)         = Store                      : &:r0_15, r0_9
+#   16|     v0_17(Void)            = ReturnVoid                 : 
+#   16|     v0_18(Void)            = UnmodeledUse               : mu*
+#   16|     v0_19(Void)            = ExitFunction               : 
+
+#   23| System.Void Indexers.Main()
+#   23|   Block 0
+#   23|     v0_0(Void)            = EnterFunction             : 
+#   23|     mu0_1(null)           = AliasedDefinition         : 
+#   23|     mu0_2(null)           = UnmodeledDefinition       : 
+#   25|     r0_3(glval<MyClass>)  = VariableAddress[inst]     : 
+#   25|     r0_4(MyClass)         = NewObj                    : 
+#   25|     r0_5(glval<null>)     = FunctionAddress[MyClass]  : 
+#   25|     v0_6(Void)            = Call                      : func:r0_5, this:r0_4
+#   25|     mu0_7(null)           = ^CallSideEffect           : ~mu0_2
+#   25|     mu0_8(MyClass)        = Store                     : &:r0_3, r0_4
+#   26|     r0_9(glval<MyClass>)  = VariableAddress[inst]     : 
+#   26|     r0_10(MyClass)        = Load                      : &:r0_9, ~mu0_2
+#   26|     r0_11(glval<null>)    = FunctionAddress[set_Item] : 
+#   26|     r0_12(Int32)          = Constant[0]               : 
+#   26|     r0_13(String)         = StringConstant["str1"]    : 
+#   26|     v0_14(Void)           = Call                      : func:r0_11, this:r0_10, 0:r0_12, 1:r0_13
+#   26|     mu0_15(null)          = ^CallSideEffect           : ~mu0_2
+#   27|     r0_16(glval<MyClass>) = VariableAddress[inst]     : 
+#   27|     r0_17(MyClass)        = Load                      : &:r0_16, ~mu0_2
+#   27|     r0_18(glval<null>)    = FunctionAddress[set_Item] : 
+#   27|     r0_19(Int32)          = Constant[1]               : 
+#   27|     r0_20(String)         = StringConstant["str1"]    : 
+#   27|     v0_21(Void)           = Call                      : func:r0_18, this:r0_17, 0:r0_19, 1:r0_20
+#   27|     mu0_22(null)          = ^CallSideEffect           : ~mu0_2
+#   28|     r0_23(glval<MyClass>) = VariableAddress[inst]     : 
+#   28|     r0_24(MyClass)        = Load                      : &:r0_23, ~mu0_2
+#   28|     r0_25(glval<null>)    = FunctionAddress[set_Item] : 
+#   28|     r0_26(Int32)          = Constant[1]               : 
+#   28|     r0_27(glval<MyClass>) = VariableAddress[inst]     : 
+#   28|     r0_28(MyClass)        = Load                      : &:r0_27, ~mu0_2
+#   28|     r0_29(glval<null>)    = FunctionAddress[get_Item] : 
+#   28|     r0_30(Int32)          = Constant[0]               : 
+#   28|     r0_31(String)         = Call                      : func:r0_29, this:r0_28, 0:r0_30
+#   28|     mu0_32(null)          = ^CallSideEffect           : ~mu0_2
+#   28|     v0_33(Void)           = Call                      : func:r0_25, this:r0_24, 0:r0_26, 1:r0_31
+#   28|     mu0_34(null)          = ^CallSideEffect           : ~mu0_2
+#   23|     v0_35(Void)           = ReturnVoid                : 
+#   23|     v0_36(Void)           = UnmodeledUse              : mu*
+#   23|     v0_37(Void)           = ExitFunction              : 
+
 inheritance_polymorphism.cs:
 #    3| System.Int32 A.function()
 #    3|   Block 0