C++: Remove ConvertToVoid, replace with Convert

Author: dave-bartolomeo

cpp/ql/src/semmle/code/cpp/ir/internal/Opcode.qll

@@ -33,7 +33,6 @@ private newtype TOpcode =
   TPointerSub() or
   TPointerDiff() or
   TConvert() or
-  TConvertToVoid() or
   TConvertToBase() or
   TConvertToVirtualBase() or
   TConvertToDerived() or
@@ -126,7 +125,6 @@ module Opcode {
   class PointerSub extends PointerOffsetOpcode, TPointerSub { override final string toString() { result = "PointerSub" } }
   class PointerDiff extends PointerArithmeticOpcode, TPointerDiff { override final string toString() { result = "PointerDiff" } }
   class Convert extends UnaryOpcode, TConvert { override final string toString() { result = "Convert" } }
-  class ConvertToVoid extends UnaryOpcode, TConvertToVoid { override final string toString() { result = "ConvertToVoid" } }
   class ConvertToBase extends UnaryOpcode, TConvertToBase { override final string toString() { result = "ConvertToBase" } }
   class ConvertToVirtualBase extends UnaryOpcode, TConvertToVirtualBase { override final string toString() { result = "ConvertToVirtualBase" } }
   class ConvertToDerived extends UnaryOpcode, TConvertToDerived { override final string toString() { result = "ConvertToDerived" } }

cpp/ql/src/semmle/code/cpp/ir/internal/TranslatedExpr.qll

@@ -1126,19 +1126,6 @@ abstract class TranslatedSingleInstructionConversion extends TranslatedConversio
   abstract Opcode getOpcode();
 }
 
-/**
- * The translation of an explicit cast to `void`.
- */
-class TranslatedVoidConversion extends TranslatedSingleInstructionConversion {
-  TranslatedVoidConversion() {
-    conv instanceof VoidConversion
-  }
-
-  override Opcode getOpcode() {
-    result instanceof Opcode::ConvertToVoid
-  }
-}
-
 /**
  * Represents the translation of a conversion expression that generates a
  * `Convert` instruction.
@@ -1152,7 +1139,8 @@ class TranslatedSimpleConversion extends TranslatedSingleInstructionConversion {
     conv instanceof IntegralToPointerConversion or
     conv instanceof GlvalueConversion or
     conv instanceof ArrayToPointerConversion or
-    conv instanceof PrvalueAdjustmentConversion
+    conv instanceof PrvalueAdjustmentConversion or
+    conv instanceof VoidConversion
   }
 
   override Opcode getOpcode() {

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

@@ -3855,7 +3855,7 @@ ir.cpp:
 #  900|     r0_3(glval<int>) = VariableAddress[x]     : 
 #  900|     mu0_4(int)       = Store                  : r0_3, r0_2
 #  901|     r0_5(glval<int>) = VariableAddress[x]     : 
-#  901|     v0_6(void)       = ConvertToVoid          : r0_5
+#  901|     v0_6(void)       = Convert                : r0_5
 #  902|     v0_7(void)       = NoOp                   : 
 #  900|     v0_8(void)       = ReturnVoid             : 
 #  900|     v0_9(void)       = UnmodeledUse           : mu*

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

@@ -3835,7 +3835,7 @@ ir.cpp:
 #  900|     r0_3(glval<int>) = VariableAddress[x]     : 
 #  900|     mu0_4(int)       = Store                  : r0_3, r0_2
 #  901|     r0_5(glval<int>) = VariableAddress[x]     : 
-#  901|     v0_6(void)       = ConvertToVoid          : r0_5
+#  901|     v0_6(void)       = Convert                : r0_5
 #  902|     v0_7(void)       = NoOp                   : 
 #  900|     v0_8(void)       = ReturnVoid             : 
 #  900|     v0_9(void)       = UnmodeledUse           : mu*

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

@@ -3855,7 +3855,7 @@ ir.cpp:
 #  900|     r0_3(glval<int>) = VariableAddress[x]     : 
 #  900|     mu0_4(int)       = Store                  : r0_3, r0_2
 #  901|     r0_5(glval<int>) = VariableAddress[x]     : 
-#  901|     v0_6(void)       = ConvertToVoid          : r0_5
+#  901|     v0_6(void)       = Convert                : r0_5
 #  902|     v0_7(void)       = NoOp                   : 
 #  900|     v0_8(void)       = ReturnVoid             : 
 #  900|     v0_9(void)       = UnmodeledUse           : mu*