Enabled casting for polymorphic functions at the ASR level

lcompilers · Aug 15, 2024 · 0b3bec4 · 0b3bec4
1 parent 846c59c
commit 0b3bec4
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Showing 5 changed files with 43 additions and 3 deletions.
diff --git a/integration_tests/class_06.py b/integration_tests/class_06.py
@@ -0,0 +1,19 @@
+from lpython import i32
+class Base():
+    def __init__(self:"Base"):
+        self.x : i32 = 10
+
+class Derived(Base):
+    # def __init__(self: "Derived"):
+    #     super().__init__()
+    #     self.y : i32 = 20
+    pass
+
+def f(i:Base):
+    print(i.x)
+
+def main():
+    d : Derived = Derived()
+    f(d)
+
+main()
diff --git a/src/libasr/ASR.asdl b/src/libasr/ASR.asdl
@@ -215,7 +215,7 @@ ttype
     | Array(ttype type, dimension* dims, array_physical_type physical_type)
     | FunctionType(ttype* arg_types, ttype? return_var_type, abi abi, deftype deftype, string? bindc_name, bool elemental, bool pure, bool module, bool inline, bool static, symbol* restrictions, bool is_restriction)
 
-cast_kind = RealToInteger | IntegerToReal | LogicalToReal | RealToReal | IntegerToInteger | RealToComplex | IntegerToComplex | IntegerToLogical | RealToLogical | CharacterToLogical | CharacterToInteger | CharacterToList | ComplexToLogical | ComplexToComplex | ComplexToReal | ComplexToInteger | LogicalToInteger | RealToCharacter | IntegerToCharacter | LogicalToCharacter | UnsignedIntegerToInteger | UnsignedIntegerToUnsignedInteger | UnsignedIntegerToReal | UnsignedIntegerToLogical | IntegerToUnsignedInteger | RealToUnsignedInteger | CPtrToUnsignedInteger | UnsignedIntegerToCPtr | IntegerToSymbolicExpression | ListToArray
+cast_kind = RealToInteger | IntegerToReal | LogicalToReal | RealToReal | IntegerToInteger | RealToComplex | IntegerToComplex | IntegerToLogical | RealToLogical | CharacterToLogical | CharacterToInteger | CharacterToList | ComplexToLogical | ComplexToComplex | ComplexToReal | ComplexToInteger | LogicalToInteger | RealToCharacter | IntegerToCharacter | LogicalToCharacter | UnsignedIntegerToInteger | UnsignedIntegerToUnsignedInteger | UnsignedIntegerToReal | UnsignedIntegerToLogical | IntegerToUnsignedInteger | RealToUnsignedInteger | CPtrToUnsignedInteger | UnsignedIntegerToCPtr | IntegerToSymbolicExpression | ListToArray | DerivedToBase
 storage_type = Default | Save | Parameter
 access = Public | Private
 intent = Local | In | Out | InOut | ReturnVar | Unspecified

diff --git a/src/libasr/casting_utils.cpp b/src/libasr/casting_utils.cpp
@@ -41,7 +41,8 @@ namespace LCompilers::CastingUtil {
         {ASR::ttypeType::Complex, ASR::cast_kindType::ComplexToComplex},
         {ASR::ttypeType::Real, ASR::cast_kindType::RealToReal},
         {ASR::ttypeType::Integer, ASR::cast_kindType::IntegerToInteger},
-        {ASR::ttypeType::UnsignedInteger, ASR::cast_kindType::UnsignedIntegerToUnsignedInteger}
+        {ASR::ttypeType::UnsignedInteger, ASR::cast_kindType::UnsignedIntegerToUnsignedInteger},
+        {ASR::ttypeType::StructType, ASR::cast_kindType::DerivedToBase}
     };
 
     int get_type_priority(ASR::ttypeType type) {

diff --git a/src/libasr/codegen/asr_to_llvm.cpp b/src/libasr/codegen/asr_to_llvm.cpp
@@ -7709,6 +7709,9 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
                 tmp = LLVM::CreateLoad(*builder, list_api->get_pointer_to_list_data(tmp));
                 break;
             }
+            case (ASR::cast_kindType::DerivedToBase) : {
+                //TODO: Implement the cast here
+            }
             default : throw CodeGenError("Cast kind not implemented");
         }
     }

diff --git a/src/lpython/semantics/python_ast_to_asr.cpp b/src/lpython/semantics/python_ast_to_asr.cpp
@@ -784,9 +784,26 @@ class CommonVisitor : public AST::BaseVisitor<Struct> {
             ASR::call_arg_t c_arg;
             c_arg.loc = args[i].loc;
             c_arg.m_value = args[i].m_value;
-            cast_helper(m_args[i], c_arg.m_value, true);
             ASR::ttype_t* left_type = ASRUtils::expr_type(m_args[i]);
             ASR::ttype_t* right_type = ASRUtils::expr_type(c_arg.m_value);
+            if ( ASR::is_a<ASR::StructType_t>(*left_type) && ASR::is_a<ASR::StructType_t>(*right_type) ) {
+                ASR::StructType_t *l_type = ASR::down_cast<ASR::StructType_t>(left_type);
+                ASR::StructType_t *r_type = ASR::down_cast<ASR::StructType_t>(right_type);
+                ASR::Struct_t *l2_type = ASR::down_cast<ASR::Struct_t>(
+                                                ASRUtils::symbol_get_past_external(
+                                                    l_type->m_derived_type));
+                ASR::Struct_t *r2_type = ASR::down_cast<ASR::Struct_t>(
+                                                ASRUtils::symbol_get_past_external(
+                                                    r_type->m_derived_type));
+                if ( ASRUtils::is_derived_type_similar(l2_type, r2_type) ) {
+                    cast_helper(m_args[i], c_arg.m_value, true, true); 
+                    check_type_equality = false;
+                } else {
+                    cast_helper(m_args[i], c_arg.m_value, true);    
+                }
+            } else {
+                cast_helper(m_args[i], c_arg.m_value, true);
+            }
             if( check_type_equality && !ASRUtils::check_equal_type(left_type, right_type) ) {
                 std::string ltype = ASRUtils::type_to_str_python(left_type);
                 std::string rtype = ASRUtils::type_to_str_python(right_type);