Binary: Add IR for 'dup' instructions.

Author: MathiasVP

binary/ql/lib/semmle/code/binary/ast/ir/internal/Instruction0/TempVariableTag.qll

@@ -31,7 +31,8 @@ newtype TTempVariableTag =
   CilLoadArgVarTag() or
   CilLdindVarTag() or
   CilNewObjInitVarTag() or
-  CilNewObjCallExternalVarTag()
+  CilNewObjCallExternalVarTag() or
+  CilDupVarTag()
 
 class TempVariableTag extends TTempVariableTag {
   string toString() {
@@ -133,5 +134,8 @@ class TempVariableTag extends TTempVariableTag {
     or
     this = CilNewObjCallExternalVarTag() and
     result = "newobj_ext"
+    or
+    this = CilDupVarTag() and
+    result = "dup"
   }
 }

binary/ql/lib/semmle/code/binary/ast/ir/internal/Instruction0/TranslatedElement.qll

@@ -133,7 +133,8 @@ newtype TTranslatedElement =
     shouldTranslateCilInstr(stind)
   } or
   TTranslatedCilType(Raw::CilType type) { shouldTranslatedCilType(type) } or
-  TTranslatedNewObject(Raw::CilNewobj newObj) { shouldTranslateCilInstr(newObj) }
+  TTranslatedNewObject(Raw::CilNewobj newObj) { shouldTranslateCilInstr(newObj) } or
+  TTranslatedDup(Raw::CilDup dup) { shouldTranslateCilInstr(dup) }
 
 TranslatedElement getTranslatedElement(Raw::Element raw) {
   result.getRawElement() = raw and

binary/ql/lib/semmle/code/binary/ast/ir/internal/Instruction0/TranslatedInstruction.qll

@@ -2505,3 +2505,47 @@ class TranslatedNewObject extends TranslatedCilInstruction, TTranslatedNewObject
             .getStackElement(i + instr.getNumberOfArguments())
   }
 }
+
+class TranslatedDup extends TranslatedCilInstruction, TTranslatedDup {
+  override Raw::CilDup instr;
+
+  TranslatedDup() { this = TTranslatedDup(instr) }
+
+  final override predicate hasInstruction(
+    Opcode opcode, InstructionTag tag, Option<Variable>::Option v
+  ) {
+    opcode instanceof Opcode::Copy and
+    tag = SingleTag() and
+    v.asSome() = this.getTempVariable(CilDupVarTag())
+  }
+
+  override predicate hasTempVariable(TempVariableTag tag) { tag = CilDupVarTag() }
+
+  override predicate producesResult() { any() }
+
+  override Variable getVariableOperand(InstructionTag tag, OperandTag operandTag) {
+    tag = SingleTag() and
+    operandTag instanceof UnaryTag and
+    result = getTranslatedCilInstruction(instr.getABackwardPredecessor()).getStackElement(0)
+  }
+
+  override Instruction getChildSuccessor(TranslatedElement child, SuccessorType succType) { none() }
+
+  override Instruction getSuccessor(InstructionTag tag, SuccessorType succType) {
+    tag = SingleTag() and
+    succType instanceof DirectSuccessor and
+    result = getTranslatedInstruction(instr.getASuccessor()).getEntry()
+  }
+
+  override Instruction getEntry() { result = this.getInstruction(SingleTag()) }
+
+  override Variable getResultVariable() { result = this.getTempVariable(CilDupVarTag()) }
+
+  final override Variable getStackElement(int i) {
+    i = 0 and
+    result = this.getInstruction(SingleTag()).getResultVariable()
+    or
+    i > 0 and
+    result = getTranslatedCilInstruction(instr.getABackwardPredecessor()).getStackElement(i - 1)
+  }
+}