Changeset c5e3208 for src/SynTree

Timestamp:

Jul 12, 2017, 5:20:59 PM (7 years ago)

Author:

Rob Schluntz <rschlunt@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

c6976ba

Parents:

49148d5

Message:

Properly assign types to AddressExpr?

File:

• src/SynTree/AddressExpr.cc (modified) (1 diff)

src/SynTree/AddressExpr.cc

@@ -18 +18 @@
 #include "Common/utility.h"
 
+// Address expressions are typed based on the following inference rules:
+//    E : lvalue T  &..& (n references)
+//   &E :        T *&..& (n references)
+//
+//    E : T  &..&        (m references)
+//   &E : T *&..&        (m-1 references)
+//
+// That is, lvalues becomes
+
+namespace {
+        Type * addrType( Type * type ) {
+                if ( ReferenceType * refType = dynamic_cast< ReferenceType * >( type ) ) {
+                        return new ReferenceType( refType->get_qualifiers(), addrType( refType->get_base() ) );
+                } else {
+                        return new PointerType( Type::Qualifiers(), type->clone() );
+                }
+        }
+}
+
 AddressExpr::AddressExpr( Expression *arg, Expression *_aname ) : Expression( _aname ), arg( arg ) {
         if ( arg->has_result() ) {
-                if ( ReferenceType * refType = dynamic_cast< ReferenceType * > ( arg->get_result() ) ) {
-                        // xxx - very temporary, make &ref look like **
-                        set_result( new PointerType( Type::Qualifiers( Type::Lvalue ), refType->get_base()->clone() ) );
+                if ( arg->get_result()->get_lvalue() ) {
+                        // lvalue, retains all layers of reference and gains a pointer inside the references
+                        set_result( addrType( arg->get_result() ) );
                 } else {
-                        set_result( new PointerType( Type::Qualifiers(), arg->get_result()->clone() ) );
+                        // taking address of non-lvalue -- must be a reference, loses one layer of reference
+                        ReferenceType * refType = safe_dynamic_cast< ReferenceType * >( arg->get_result() );
+                        set_result( addrType( refType->get_base() ) );
                 }
+                // result of & is never an lvalue
+                get_result()->set_lvalue( false );
         }
 }