Changes in src/AST/Expr.cpp [490fb92e:312029a]

File:

• src/AST/Expr.cpp (modified) (13 diffs)

src/AST/Expr.cpp

@@ -20 +20 @@
 #include <vector>
 
-#include "Copy.hpp"                // for shallowCopy
-#include "Eval.hpp"                // for call
 #include "GenericSubstitution.hpp"
-#include "LinkageSpec.hpp"
 #include "Stmt.hpp"
 #include "Type.hpp"
@@ -30 +27 @@
 #include "Common/SemanticError.h"
 #include "GenPoly/Lvalue.h"        // for referencesPermissable
-#include "InitTweak/InitTweak.h"   // for getFunction, getPointerBase
+#include "InitTweak/InitTweak.h"   // for getPointerBase
 #include "ResolvExpr/typeops.h"    // for extractResultType
 #include "Tuples/Tuples.h"         // for makeTupleType
 
 namespace ast {
-
-namespace {
-        std::set<std::string> const lvalueFunctionNames = {"*?", "?[?]"};
-}
-
-// --- Expr
-bool Expr::get_lvalue() const {
-        return false;
-}
 
 // --- ApplicationExpr
@@ -58 +46 @@
 }
 
-bool ApplicationExpr::get_lvalue() const {
-        if ( const DeclWithType * func = InitTweak::getFunction( this ) ) {
-                return func->linkage == Linkage::Intrinsic && lvalueFunctionNames.count( func->name );
-        }
-        return false;
-}
-
 // --- UntypedExpr
 
-UntypedExpr * UntypedExpr::createDeref( const CodeLocation & loc, const Expr * arg ) {
+UntypedExpr * UntypedExpr::createDeref( const CodeLocation & loc, Expr * arg ) {
         assert( arg );
 
-        UntypedExpr * ret = call( loc, "*?", arg );
+        UntypedExpr * ret = new UntypedExpr{
+                loc, new NameExpr{loc, "*?"}, std::vector<ptr<Expr>>{ ptr<Expr>{ arg } }
+        };
         if ( const Type * ty = arg->result ) {
                 const Type * base = InitTweak::getPointerBase( ty );
@@ -82 +65 @@
                         // base type
                         ret->result = base;
+                        add_qualifiers( ret->result, CV::Lvalue );
                 }
         }
@@ -87 +71 @@
 }
 
-bool UntypedExpr::get_lvalue() const {
-        std::string fname = InitTweak::getFunctionName( this );
-        return lvalueFunctionNames.count( fname );
-}
-
-UntypedExpr * UntypedExpr::createAssign( const CodeLocation & loc, const Expr * lhs, const Expr * rhs ) {
+UntypedExpr * UntypedExpr::createAssign( const CodeLocation & loc, Expr * lhs, Expr * rhs ) {
         assert( lhs && rhs );
 
-        UntypedExpr * ret = call( loc, "?=?", lhs, rhs );
+        UntypedExpr * ret = new UntypedExpr{
+                loc, new NameExpr{loc, "?=?"}, std::vector<ptr<Expr>>{ ptr<Expr>{ lhs }, ptr<Expr>{ rhs } }
+        };
         if ( lhs->result && rhs->result ) {
                 // if both expressions are typed, assumes that this assignment is a C bitwise assignment,
@@ -127 +108 @@
 AddressExpr::AddressExpr( const CodeLocation & loc, const Expr * a ) : Expr( loc ), arg( a ) {
         if ( arg->result ) {
-                if ( arg->get_lvalue() ) {
+                if ( arg->result->is_lvalue() ) {
                         // lvalue, retains all levels of reference, and gains a pointer inside the references
                         Type * res = addrType( arg->result );
+                        res->set_lvalue( false ); // result of & is never an lvalue
                         result = res;
                 } else {
@@ -136 +118 @@
                                         dynamic_cast< const ReferenceType * >( arg->result.get() ) ) {
                                 Type * res = addrType( refType->base );
+                                res->set_lvalue( false ); // result of & is never an lvalue
                                 result = res;
                         } else {
@@ -156 +139 @@
 : Expr( loc, new VoidType{} ), arg( a ), isGenerated( g ) {}
 
-bool CastExpr::get_lvalue() const {
-        // This is actually wrong by C, but it works with our current set-up.
-        return arg->get_lvalue();
-}
-
 // --- KeywordCastExpr
 
 const char * KeywordCastExpr::targetString() const {
         return AggregateDecl::aggrString( target );
-}
-
-// --- UntypedMemberExpr
-
-bool UntypedMemberExpr::get_lvalue() const {
-        return aggregate->get_lvalue();
 }
 
@@ -181 +153 @@
         assert( aggregate->result );
 
-        // Deep copy on result type avoids mutation on transitively multiply referenced object.
-        //
-        // Example, adapted from parts of builtins and bootloader:
-        //
-        // forall(dtype T)
-        // struct __Destructor {
-        //   T * object;
-        //   void (*dtor)(T *);
-        // };
-        //
-        // forall(dtype S)
-        // void foo(__Destructor(S) &d) {
-        //   if (d.dtor) {  // here
-        //   }
-        // }
-        //
-        // Let e be the "d.dtor" guard espression, which is MemberExpr after resolve.  Let d be the
-        // declaration of member __Destructor.dtor (an ObjectDecl), as accessed via the top-level
-        // declaration of __Destructor.  Consider the types e.result and d.type.  In the old AST, one
-        // is a clone of the other.  Ordinary new-AST use would set them up as a multiply-referenced
-        // object.
-        //
-        // e.result: PointerType
-        // .base: FunctionType
-        // .params.front(): ObjectDecl, the anonymous parameter of type T*
-        // .type: PointerType
-        // .base: TypeInstType
-        // let x = that
-        // let y = similar, except start from d.type
-        //
-        // Consider two code lines down, genericSubstitution(...).apply(result).
-        //
-        // Applying this chosen-candidate's type substitution means modifying x, substituting
-        // S for T.  This mutation should affect x and not y.
-
-        result = deepCopy(mem->get_type());
-
+        // take ownership of member type
+        result = mem->get_type();
         // substitute aggregate generic parameters into member type
         genericSubstitution( aggregate->result ).apply( result );
-        // ensure appropriate restrictions from aggregate type
-        add_qualifiers( result, aggregate->result->qualifiers );
-}
-
-MemberExpr::MemberExpr( const CodeLocation & loc, const DeclWithType * mem, const Expr * agg,
-    MemberExpr::NoOpConstruction overloadSelector )
-: Expr( loc ), member( mem ), aggregate( agg ) {
-        assert( member );
-        assert( aggregate );
-        assert( aggregate->result );
-        (void) overloadSelector;
-}
-
-bool MemberExpr::get_lvalue() const {
-        // This is actually wrong by C, but it works with our current set-up.
-        return true;
+        // ensure lvalue and appropriate restrictions from aggregate type
+        add_qualifiers( result, aggregate->result->qualifiers | CV::Lvalue );
 }
 
@@ -247 +170 @@
         assert( var );
         assert( var->get_type() );
-        result = shallowCopy( var->get_type() );
-}
-
-bool VariableExpr::get_lvalue() const {
-        // It isn't always an lvalue, but it is never an rvalue.
-        return true;
+        result = var->get_type();
+        add_qualifiers( result, CV::Lvalue );
 }
 
@@ -338 +257 @@
         const CodeLocation & loc, const Expr * a1, const Expr * a2, LogicalFlag ia )
 : Expr( loc, new BasicType{ BasicType::SignedInt } ), arg1( a1 ), arg2( a2 ), isAnd( ia ) {}
-
-// --- CommaExpr
-bool CommaExpr::get_lvalue() const {
-        // This is wrong by C, but the current implementation uses it.
-        // (ex: Specialize, Lvalue and Box)
-        return arg2->get_lvalue();
-}
 
 // --- ConstructorExpr
@@ -364 +276 @@
         assert( t && i );
         result = t;
-}
-
-bool CompoundLiteralExpr::get_lvalue() const {
-        return true;
+        add_qualifiers( result, CV::Lvalue );
 }
 
@@ -384 +293 @@
         // like MemberExpr, TupleIndexExpr is always an lvalue
         result = type->types[ index ];
-}
-
-bool TupleIndexExpr::get_lvalue() const {
-        return tuple->get_lvalue();
+        add_qualifiers( result, CV::Lvalue );
 }