Changeset 28e58fd for src/SynTree/AddressExpr.cc

Timestamp:

Aug 25, 2017, 10:38:34 AM (8 years ago)

Author:

Thierry Delisle <tdelisle@…>

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:

800d275

Parents:

af08051 (diff), 3eab308c (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

File:

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

src/SynTree/AddressExpr.cc

@@ -21 +21 @@
 #include "Type.h"            // for PointerType, Type, Type::Qualifiers
 
+// 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() ) {
-                set_result( new PointerType( Type::Qualifiers(), arg->get_result()->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 {
+                        // 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 );
         }
 }