validate Pointer - Numerics assignments if it is no perfect match (#516)

* validate Pointer incl. tests

src/diagnostics.rs

@@ -79,6 +79,7 @@ pub enum ErrNo {
     type__invalid_nature,
     type__unknown_nature,
     type__unresolved_generic,
+    type__incompatible_size,
 
     //codegen related
     codegen__general,
@@ -513,6 +514,22 @@ impl Diagnostic {
         }
     }
 
+    pub fn incompatible_type_size(
+        nature: &str,
+        size: u32,
+        error: &str,
+        location: SourceRange,
+    ) -> Diagnostic {
+        Diagnostic::SyntaxError {
+            message: format!(
+                "The type {} {} is too small to {} Pointer",
+                nature, size, error
+            ),
+            range: location,
+            err_no: ErrNo::type__incompatible_size,
+        }
+    }
+
     pub fn link_error(error: &str) -> Diagnostic {
         Diagnostic::GeneralError {
             err_no: ErrNo::linker__generic_error,

src/typesystem.rs

@@ -27,6 +27,7 @@ pub type NativeDwordType = u32;
 pub type NativeLwordType = u64;
 pub type NativeRealType = f32;
 pub type NativeLrealType = f64;
+pub type NativePointerType = usize;
 
 //TODO should we change this to usize?
 pub const U1_SIZE: u32 = 1;
@@ -39,6 +40,7 @@ pub const LINT_SIZE: u32 = NativeLintType::BITS as u32;
 pub const REAL_SIZE: u32 = (size_of::<NativeRealType>() * 8) as u32;
 pub const LREAL_SIZE: u32 = (size_of::<NativeLrealType>() * 8) as u32;
 pub const DATE_TIME_SIZE: u32 = 64;
+pub const POINTER_SIZE: u32 = NativePointerType::BITS as u32;
 
 pub const U1_TYPE: &str = "__U1";
 /// used internally for forced casts to u1

src/validation/stmt_validator.rs

@@ -7,8 +7,9 @@ use crate::{
     resolver::{AnnotationMap, StatementAnnotation},
     typesystem::{
         DataType, DataTypeInformation, Dimension, BOOL_TYPE, DATE_AND_TIME_TYPE, DATE_TYPE,
-        DINT_TYPE, INT_TYPE, LINT_TYPE, LREAL_TYPE, SINT_TYPE, STRING_TYPE, TIME_OF_DAY_TYPE,
-        TIME_TYPE, UDINT_TYPE, UINT_TYPE, ULINT_TYPE, USINT_TYPE, VOID_TYPE, WSTRING_TYPE,
+        DINT_TYPE, INT_TYPE, LINT_TYPE, LREAL_TYPE, POINTER_SIZE, SINT_TYPE, STRING_TYPE,
+        TIME_OF_DAY_TYPE, TIME_TYPE, UDINT_TYPE, UINT_TYPE, ULINT_TYPE, USINT_TYPE, VOID_TYPE,
+        WSTRING_TYPE,
     },
     Diagnostic,
 };
@@ -137,6 +138,31 @@ impl StatementValidator {
                         .get_type_or_void(right, context.index)
                         .get_type_information();
 
+                    //check if Datatype can hold a Pointer (u64)
+                    if r_effective_type.is_pointer()
+                        && !l_effective_type.is_pointer()
+                        && l_effective_type.get_size() < POINTER_SIZE
+                    {
+                        self.diagnostics.push(Diagnostic::incompatible_type_size(
+                            l_effective_type.get_name(),
+                            l_effective_type.get_size(),
+                            "hold a",
+                            statement.get_location(),
+                        ));
+                    }
+                    //check if size allocated to Pointer is standart pointer size (u64)
+                    else if l_effective_type.is_pointer()
+                        && !r_effective_type.is_pointer()
+                        && r_effective_type.get_size() < POINTER_SIZE
+                    {
+                        self.diagnostics.push(Diagnostic::incompatible_type_size(
+                            r_effective_type.get_name(),
+                            r_effective_type.get_size(),
+                            "to be stored in a",
+                            statement.get_location(),
+                        ));
+                    }
+
                     // valid assignments -> char := literalString, char := char
                     // check if we assign to a character variable -> char := ..
                     if l_effective_type.is_character() {

src/validation/tests/statement_validation_tests.rs

@@ -1,6 +1,88 @@
 use crate::test_utils::tests::parse_and_validate;
 use crate::Diagnostic;
 
+#[test]
+fn assign_pointer_to_too_small_type_result_in_an_error() {
+    //GIVEN assignment statements to DWORD
+    //WHEN it is validated
+    let diagnostics: Vec<Diagnostic> = parse_and_validate(
+        "
+        PROGRAM FOO
+            VAR
+                ptr : POINTER TO INT;
+                address : DWORD;
+            END_VAR
+            
+            address := 16#DEAD_BEEF;              
+            address := ptr;         //should throw error as address is too small to store full pointer
+        END_PROGRAM
+        ",
+    );
+
+    //THEN assignment with different type sizes are reported
+    assert_eq!(
+        diagnostics,
+        vec![Diagnostic::incompatible_type_size(
+            "DWORD",
+            32,
+            "hold a",
+            (204..218).into()
+        ),]
+    );
+}
+
+#[test]
+fn assign_too_small_type_to_pointer_result_in_an_error() {
+    //GIVEN assignment statements to pointer
+    //WHEN it is validated
+    let diagnostics: Vec<Diagnostic> = parse_and_validate(
+        "
+        PROGRAM FOO
+            VAR
+                ptr : POINTER TO INT;
+                address : DWORD;
+            END_VAR
+            
+            address := 16#DEAD_BEEF;              
+            ptr := address;         //should throw error as address is too small to store full pointer
+        END_PROGRAM
+        ",
+    );
+
+    //THEN assignment with different type sizes are reported
+    assert_eq!(
+        diagnostics,
+        vec![Diagnostic::incompatible_type_size(
+            "DWORD",
+            32,
+            "to be stored in a",
+            (204..218).into()
+        ),]
+    );
+}
+
+#[test]
+fn assign_pointer_to_lword() {
+    //GIVEN assignment statements to lword
+    //WHEN it is validated
+    let diagnostics: Vec<Diagnostic> = parse_and_validate(
+        "
+        PROGRAM FOO
+            VAR
+                ptr : POINTER TO INT;
+                address : LWORD;
+            END_VAR
+            
+            address := 16#DEAD_BEEF;              
+            address := ptr;         //should throw error as address is too small to store full pointer
+        END_PROGRAM
+        ",
+    );
+
+    //THEN every assignment is valid
+    assert_eq!(diagnostics, vec![]);
+}
+
 #[test]
 fn assignment_to_constants_result_in_an_error() {
     // GIVEN assignment statements to constants, some to writable variables