C# IR: Initializers

Add support for collection initializers.
Instead of using `AssignExpr` for the translation of object initializers, `MemberInitializer` is now used.

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

@@ -4,6 +4,7 @@ private import semmle.code.csharp.ir.implementation.internal.OperandTag
 private import InstructionTag
 private import TranslatedElement
 private import TranslatedExpr
+private import TranslatedInitialization
 private import semmle.code.csharp.ir.Util
 private import semmle.code.csharp.ir.implementation.raw.internal.common.TranslatedCallBase
 private import semmle.code.csharp.ir.internal.IRCSharpLanguage as Language
@@ -50,7 +51,13 @@ class TranslatedFunctionCall extends TranslatedNonConstantExpr, TranslatedCall {
     result = getTranslatedExpr(expr.(QualifiableExpr).getQualifier())
   }
 
-  override Instruction getQualifierResult() { result = this.getQualifier().getResult() }
+  override Instruction getQualifierResult() {
+    // since `ElementInitializer`s do not have a qualifier, the qualifier's result is retrieved
+    // from the enclosing initialization context
+    if expr.getParent() instanceof CollectionInitializer
+    then result = getTranslatedExpr(expr.getParent()).(InitializationContext).getTargetAddress()
+    else result = this.getQualifier().getResult()
+  }
 
   override Type getCallResultType() { result = expr.getTarget().getReturnType() }
 

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

@@ -485,11 +485,7 @@ class TranslatedObjectInitializerExpr extends TranslatedNonConstantExpr, Initial
   }
 
   override TranslatedElement getChild(int id) {
-    exists(AssignExpr assign |
-      result = getTranslatedExpr(expr.getChild(id)) and
-      expr.getAChild() = assign and
-      assign.getIndex() = id
-    )
+    result = getTranslatedExpr(expr.getMemberInitializer(id))
   }
 
   override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) { none() }
@@ -503,9 +499,54 @@ class TranslatedObjectInitializerExpr extends TranslatedNonConstantExpr, Initial
     )
   }
 
-  override Instruction getTargetAddress() { result = this.getParent().getInstruction(NewObjTag()) }
+  override Instruction getTargetAddress() {
+    // The target address is the address of the newly allocated object,
+    // which can be retrieved from the parent `TranslatedObjectCreation`.
+    result = this.getParent().getInstruction(NewObjTag())
+  }
 
-  override Type getTargetType() { none() }
+  override Type getTargetType() {
+    result = this.getParent().getInstruction(NewObjTag()).getResultType()
+  }
+}
+
+class TranslatedCollectionInitializer extends TranslatedNonConstantExpr, InitializationContext {
+  override CollectionInitializer expr;
+
+  override Instruction getResult() { none() }
+
+  override Instruction getFirstInstruction() { result = this.getChild(0).getFirstInstruction() }
+
+  override predicate hasInstruction(
+    Opcode opcode, InstructionTag tag, Type resultType, boolean isLValue
+  ) {
+    none()
+  }
+
+  override TranslatedElement getChild(int id) {
+    result = getTranslatedExpr(expr.getElementInitializer(id))
+  }
+
+  override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) { none() }
+
+  override Instruction getChildSuccessor(TranslatedElement child) {
+    exists(int index |
+      child = this.getChild(index) and
+      if exists(this.getChild(index + 1))
+      then result = this.getChild(index + 1).getFirstInstruction()
+      else result = this.getParent().getChildSuccessor(this)
+    )
+  }
+
+  override Instruction getTargetAddress() {
+    // The target address is the address of the newly allocated object,
+    // which can be retrieved from the parent `TranslatedObjectCreation`.
+    result = this.getParent().getInstruction(NewObjTag())
+  }
+
+  override Type getTargetType() {
+    result = this.getParent().getInstruction(NewObjTag()).getResultType()
+  }
 }
 
 /**

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

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+
+public class Collections
+{
+    class MyClass
+    {
+        public string a;
+        public string b;
+    }
+
+    public static void Main()
+    {
+        var dict = new Dictionary<int, MyClass>()
+        {
+            { 0, new MyClass { a="Hello", b="World" } },
+            { 1, new MyClass { a="Foo", b="Bar" } }
+        };
+    }
+}

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

@@ -161,6 +161,50 @@ casts.cs:
 #   11|     v0_20(Void)           = UnmodeledUse             : mu*
 #   11|     v0_21(Void)           = ExitFunction             : 
 
+collections.cs:
+#   11| System.Void Collections.Main()
+#   11|   Block 0
+#   11|     v0_0(Void)                             = EnterFunction               : 
+#   11|     mu0_1(null)                            = AliasedDefinition           : 
+#   11|     mu0_2(null)                            = UnmodeledDefinition         : 
+#   13|     r0_3(glval<Dictionary<Int32,MyClass>>) = VariableAddress[dict]       : 
+#   13|     r0_4(Dictionary<Int32,MyClass>)        = NewObj                      : 
+#   13|     r0_5(glval<null>)                      = FunctionAddress[Dictionary] : 
+#   13|     v0_6(Void)                             = Call                        : func:r0_5, this:r0_4
+#   13|     mu0_7(null)                            = ^CallSideEffect             : ~mu0_2
+#   15|     r0_8(glval<null>)                      = FunctionAddress[Add]        : 
+#   15|     r0_9(Int32)                            = Constant[0]                 : 
+#   15|     r0_10(MyClass)                         = NewObj                      : 
+#   15|     r0_11(glval<null>)                     = FunctionAddress[MyClass]    : 
+#   15|     v0_12(Void)                            = Call                        : func:r0_11, this:r0_10
+#   15|     mu0_13(null)                           = ^CallSideEffect             : ~mu0_2
+#   15|     r0_14(String)                          = StringConstant["Hello"]     : 
+#   15|     r0_15(glval<String>)                   = FieldAddress[a]             : r0_10
+#   15|     mu0_16(String)                         = Store                       : &:r0_15, r0_14
+#   15|     r0_17(String)                          = StringConstant["World"]     : 
+#   15|     r0_18(glval<String>)                   = FieldAddress[b]             : r0_10
+#   15|     mu0_19(String)                         = Store                       : &:r0_18, r0_17
+#   15|     v0_20(Void)                            = Call                        : func:r0_8, this:r0_4, 0:r0_9, 1:r0_10
+#   15|     mu0_21(null)                           = ^CallSideEffect             : ~mu0_2
+#   16|     r0_22(glval<null>)                     = FunctionAddress[Add]        : 
+#   16|     r0_23(Int32)                           = Constant[1]                 : 
+#   16|     r0_24(MyClass)                         = NewObj                      : 
+#   16|     r0_25(glval<null>)                     = FunctionAddress[MyClass]    : 
+#   16|     v0_26(Void)                            = Call                        : func:r0_25, this:r0_24
+#   16|     mu0_27(null)                           = ^CallSideEffect             : ~mu0_2
+#   16|     r0_28(String)                          = StringConstant["Foo"]       : 
+#   16|     r0_29(glval<String>)                   = FieldAddress[a]             : r0_24
+#   16|     mu0_30(String)                         = Store                       : &:r0_29, r0_28
+#   16|     r0_31(String)                          = StringConstant["Bar"]       : 
+#   16|     r0_32(glval<String>)                   = FieldAddress[b]             : r0_24
+#   16|     mu0_33(String)                         = Store                       : &:r0_32, r0_31
+#   16|     v0_34(Void)                            = Call                        : func:r0_22, this:r0_4, 0:r0_23, 1:r0_24
+#   16|     mu0_35(null)                           = ^CallSideEffect             : ~mu0_2
+#   13|     mu0_36(Dictionary<Int32,MyClass>)      = Store                       : &:r0_3, r0_4
+#   11|     v0_37(Void)                            = ReturnVoid                  : 
+#   11|     v0_38(Void)                            = UnmodeledUse                : mu*
+#   11|     v0_39(Void)                            = ExitFunction                : 
+
 constructor_init.cs:
 #    5| System.Void BaseClass..ctor()
 #    5|   Block 0