C++: Remove some usage of Instruction.getResultType()

There were a few places in the IR itself where we use `Instruction.getResultType()`, which returns the C++ `Type` of the result, instead of `Instruction.getResultIRType()`, which returns the language-neutral `IRType` of the result. By removing this usage, we can avoid evaluating `getResultType()` at all.

There are still other uses of `Instruction.getResultType()` in other libraries. We should switch those as well.

cpp/ql/src/Likely Bugs/RedundantNullCheckSimple.ql

@@ -23,7 +23,7 @@ import semmle.code.cpp.ir.ValueNumbering
 class NullInstruction extends ConstantValueInstruction {
   NullInstruction() {
     this.getValue() = "0" and
-    this.getResultType().getUnspecifiedType() instanceof PointerType
+    this.getResultIRType() instanceof IRAddressType
   }
 }
 
@@ -44,8 +44,8 @@ predicate explicitNullTestOfInstruction(Instruction checked, Instruction bool) {
   bool =
     any(ConvertInstruction convert |
       checked = convert.getUnary() and
-      convert.getResultType() instanceof BoolType and
-      checked.getResultType() instanceof PointerType
+      convert.getResultIRType() instanceof IRBooleanType and
+      checked.getResultIRType() instanceof IRAddressType
     )
 }
 

cpp/ql/src/semmle/code/cpp/ir/implementation/IRType.qll

@@ -128,7 +128,7 @@ class IRBooleanType extends IRSizedType, TIRBooleanType {
 }
 
 /**
- * A numberic type. This includes `IRSignedIntegerType`, `IRUnsignedIntegerType`, and
+ * A numeric type. This includes `IRSignedIntegerType`, `IRUnsignedIntegerType`, and
  * `IRFloatingPointType`.
  */
 class IRNumericType extends IRSizedType {
@@ -140,33 +140,40 @@ class IRNumericType extends IRSizedType {
 }
 
 /**
- * A signed two's-complement integer. Also used to represent enums whose underlying type is a signed
- * integer, as well as character types whose representation is signed.
+ * An integer type. This includes `IRSignedIntegerType` and `IRUnsignedIntegerType`.
  */
-class IRSignedIntegerType extends IRNumericType, TIRSignedIntegerType {
-  final override string toString() { result = "int" + byteSize.toString() }
-
-  final override Language::LanguageType getCanonicalLanguageType() {
-    result = Language::getCanonicalSignedIntegerType(byteSize)
+class IRIntegerType extends IRNumericType {
+  IRIntegerType() {
+    this = TIRSignedIntegerType(byteSize) or
+    this = TIRUnsignedIntegerType(byteSize)
   }
 
   pragma[noinline]
   final override int getByteSize() { result = byteSize }
 }
 
+/**
+ * A signed two's-complement integer. Also used to represent enums whose underlying type is a signed
+ * integer, as well as character types whose representation is signed.
+ */
+class IRSignedIntegerType extends IRIntegerType, TIRSignedIntegerType {
+  final override string toString() { result = "int" + byteSize.toString() }
+
+  final override Language::LanguageType getCanonicalLanguageType() {
+    result = Language::getCanonicalSignedIntegerType(byteSize)
+  }
+}
+
 /**
  * An unsigned two's-complement integer. Also used to represent enums whose underlying type is an
  * unsigned integer, as well as character types whose representation is unsigned.
  */
-class IRUnsignedIntegerType extends IRNumericType, TIRUnsignedIntegerType {
+class IRUnsignedIntegerType extends IRIntegerType, TIRUnsignedIntegerType {
   final override string toString() { result = "uint" + byteSize.toString() }
 
   final override Language::LanguageType getCanonicalLanguageType() {
     result = Language::getCanonicalUnsignedIntegerType(byteSize)
   }
-
-  pragma[noinline]
-  final override int getByteSize() { result = byteSize }
 }
 
 /**

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll

@@ -604,11 +604,16 @@ class ConstantInstruction extends ConstantValueInstruction {
 }
 
 class IntegerConstantInstruction extends ConstantInstruction {
-  IntegerConstantInstruction() { getResultType() instanceof Language::IntegralType }
+  IntegerConstantInstruction() {
+    exists(IRType resultType |
+      resultType = getResultIRType() and
+      (resultType instanceof IRIntegerType or resultType instanceof IRBooleanType)
+    )
+  }
 }
 
 class FloatConstantInstruction extends ConstantInstruction {
-  FloatConstantInstruction() { getResultType() instanceof Language::FloatingPointType }
+  FloatConstantInstruction() { getResultIRType() instanceof IRFloatingPointType }
 }
 
 class StringConstantInstruction extends VariableInstruction {

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Instruction.qll

@@ -604,11 +604,16 @@ class ConstantInstruction extends ConstantValueInstruction {
 }
 
 class IntegerConstantInstruction extends ConstantInstruction {
-  IntegerConstantInstruction() { getResultType() instanceof Language::IntegralType }
+  IntegerConstantInstruction() {
+    exists(IRType resultType |
+      resultType = getResultIRType() and
+      (resultType instanceof IRIntegerType or resultType instanceof IRBooleanType)
+    )
+  }
 }
 
 class FloatConstantInstruction extends ConstantInstruction {
-  FloatConstantInstruction() { getResultType() instanceof Language::FloatingPointType }
+  FloatConstantInstruction() { getResultIRType() instanceof IRFloatingPointType }
 }
 
 class StringConstantInstruction extends VariableInstruction {

cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll

@@ -604,11 +604,16 @@ class ConstantInstruction extends ConstantValueInstruction {
 }
 
 class IntegerConstantInstruction extends ConstantInstruction {
-  IntegerConstantInstruction() { getResultType() instanceof Language::IntegralType }
+  IntegerConstantInstruction() {
+    exists(IRType resultType |
+      resultType = getResultIRType() and
+      (resultType instanceof IRIntegerType or resultType instanceof IRBooleanType)
+    )
+  }
 }
 
 class FloatConstantInstruction extends ConstantInstruction {
-  FloatConstantInstruction() { getResultType() instanceof Language::FloatingPointType }
+  FloatConstantInstruction() { getResultIRType() instanceof IRFloatingPointType }
 }
 
 class StringConstantInstruction extends VariableInstruction {

csharp/ql/src/semmle/code/csharp/ir/implementation/IRType.qll

@@ -128,7 +128,7 @@ class IRBooleanType extends IRSizedType, TIRBooleanType {
 }
 
 /**
- * A numberic type. This includes `IRSignedIntegerType`, `IRUnsignedIntegerType`, and
+ * A numeric type. This includes `IRSignedIntegerType`, `IRUnsignedIntegerType`, and
  * `IRFloatingPointType`.
  */
 class IRNumericType extends IRSizedType {
@@ -140,33 +140,40 @@ class IRNumericType extends IRSizedType {
 }
 
 /**
- * A signed two's-complement integer. Also used to represent enums whose underlying type is a signed
- * integer, as well as character types whose representation is signed.
+ * An integer type. This includes `IRSignedIntegerType` and `IRUnsignedIntegerType`.
  */
-class IRSignedIntegerType extends IRNumericType, TIRSignedIntegerType {
-  final override string toString() { result = "int" + byteSize.toString() }
-
-  final override Language::LanguageType getCanonicalLanguageType() {
-    result = Language::getCanonicalSignedIntegerType(byteSize)
+class IRIntegerType extends IRNumericType {
+  IRIntegerType() {
+    this = TIRSignedIntegerType(byteSize) or
+    this = TIRUnsignedIntegerType(byteSize)
   }
 
   pragma[noinline]
   final override int getByteSize() { result = byteSize }
 }
 
+/**
+ * A signed two's-complement integer. Also used to represent enums whose underlying type is a signed
+ * integer, as well as character types whose representation is signed.
+ */
+class IRSignedIntegerType extends IRIntegerType, TIRSignedIntegerType {
+  final override string toString() { result = "int" + byteSize.toString() }
+
+  final override Language::LanguageType getCanonicalLanguageType() {
+    result = Language::getCanonicalSignedIntegerType(byteSize)
+  }
+}
+
 /**
  * An unsigned two's-complement integer. Also used to represent enums whose underlying type is an
  * unsigned integer, as well as character types whose representation is unsigned.
  */
-class IRUnsignedIntegerType extends IRNumericType, TIRUnsignedIntegerType {
+class IRUnsignedIntegerType extends IRIntegerType, TIRUnsignedIntegerType {
   final override string toString() { result = "uint" + byteSize.toString() }
 
   final override Language::LanguageType getCanonicalLanguageType() {
     result = Language::getCanonicalUnsignedIntegerType(byteSize)
   }
-
-  pragma[noinline]
-  final override int getByteSize() { result = byteSize }
 }
 
 /**

csharp/ql/src/semmle/code/csharp/ir/implementation/raw/Instruction.qll

@@ -604,11 +604,16 @@ class ConstantInstruction extends ConstantValueInstruction {
 }
 
 class IntegerConstantInstruction extends ConstantInstruction {
-  IntegerConstantInstruction() { getResultType() instanceof Language::IntegralType }
+  IntegerConstantInstruction() {
+    exists(IRType resultType |
+      resultType = getResultIRType() and
+      (resultType instanceof IRIntegerType or resultType instanceof IRBooleanType)
+    )
+  }
 }
 
 class FloatConstantInstruction extends ConstantInstruction {
-  FloatConstantInstruction() { getResultType() instanceof Language::FloatingPointType }
+  FloatConstantInstruction() { getResultIRType() instanceof IRFloatingPointType }
 }
 
 class StringConstantInstruction extends VariableInstruction {

csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/Instruction.qll

@@ -604,11 +604,16 @@ class ConstantInstruction extends ConstantValueInstruction {
 }
 
 class IntegerConstantInstruction extends ConstantInstruction {
-  IntegerConstantInstruction() { getResultType() instanceof Language::IntegralType }
+  IntegerConstantInstruction() {
+    exists(IRType resultType |
+      resultType = getResultIRType() and
+      (resultType instanceof IRIntegerType or resultType instanceof IRBooleanType)
+    )
+  }
 }
 
 class FloatConstantInstruction extends ConstantInstruction {
-  FloatConstantInstruction() { getResultType() instanceof Language::FloatingPointType }
+  FloatConstantInstruction() { getResultIRType() instanceof IRFloatingPointType }
 }
 
 class StringConstantInstruction extends VariableInstruction {