Changeset 1d776fd for src/GenPoly/Lvalue.cc

Timestamp:

Jul 13, 2017, 3:51:19 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:

9a1e509

Parents:

6b9b047

Message:

Implement reference conversion translation for basic reference conversions

File:

• src/GenPoly/Lvalue.cc (modified) (6 diffs)

src/GenPoly/Lvalue.cc

@@ -34 +34 @@
 #include "InitTweak/InitTweak.h"
 
+#include "Common/PassVisitor.h"
+
+// need to be careful about polymorphic references... e.g. in *? (___operator_deref__A0_1_0_0__Fd0_Pd0_intrinsic___1)
+// the variable is automatically dereferenced and this causes errors dereferencing void*.
+
 namespace GenPoly {
         namespace {
-                /// Replace uses of lvalue returns with appropriate pointers
-                class Pass1 : public Mutator {
-                  public:
-                        typedef Mutator Parent;
-                        Pass1();
-
-                        // xxx - should this happen to every expression with reference result type? probably just appexpr and varexpr?
-                        virtual Type *mutate( ReferenceType * refType );
-                        virtual Expression *mutate( VariableExpr *varExpr );
-                        virtual Expression *mutate( ApplicationExpr *appExpr );
-                        virtual Statement *mutate( ReturnStmt *appExpr );
-                        virtual DeclarationWithType *mutate( FunctionDecl *funDecl );
-                  private:
-                        DeclarationWithType* retval;
-                };
-
-                /// Replace declarations of lvalue returns with appropriate pointers
-                class Pass2 : public Visitor {
-                  public:
-                        virtual void visit( FunctionType *funType );
-                  private:
+                struct ReferenceConversions final {
+                        Expression * postmutate( CastExpr * castExpr );
+                };
+
+                /// Intrinsic functions that take reference parameters don't REALLY take reference parameters -- their reference arguments must always be implicitly dereferenced.
+                struct FixIntrinsicArgs final {
+                        Expression * postmutate( ApplicationExpr *appExpr );
+                };
+
+
+                /// Replace reference types with pointer types
+                struct ReferenceTypeElimination final {
+                        Type * postmutate( ReferenceType * refType );
                 };
 
@@ -62 +59 @@
                 /// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
                 /// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
-                class GeneralizedLvalue : public Mutator {
-                        typedef Mutator Parent;
-
-                        virtual Expression * mutate( AddressExpr * addressExpr );
+                struct GeneralizedLvalue final {
+                        Expression * postmutate( AddressExpr * addressExpr );
                 };
         } // namespace
 
         void convertLvalue( std::list< Declaration* >& translationUnit ) {
-                Pass1 p1;
-                Pass2 p2;
-                GeneralizedLvalue genLval;
-                mutateAll( translationUnit, p1 );
-                acceptAll( translationUnit, p2 );
+                std::cerr << "convertLvalue" << std::endl;
+                PassVisitor<ReferenceConversions> refCvt;
+                PassVisitor<ReferenceTypeElimination> elim;
+                PassVisitor<GeneralizedLvalue> genLval;
+                PassVisitor<FixIntrinsicArgs> fixer;
+                mutateAll( translationUnit, refCvt );
+                mutateAll( translationUnit, fixer );
+                mutateAll( translationUnit, elim );
                 mutateAll( translationUnit, genLval );
         }
@@ -82 +80 @@
                         if ( function->get_returnVals().empty() ) return 0;
                         Type *ty = function->get_returnVals().front()->get_type();
-                        return ty->get_lvalue() ? ty : 0;
+                        return dynamic_cast< ReferenceType * >( ty ) ;
                 }
 
@@ -93 +91 @@
                 }
 
-                Pass1::Pass1() {
-                }
-
-                DeclarationWithType * Pass1::mutate( FunctionDecl *funcDecl ) {
-                        if ( funcDecl->get_statements() ) {
-                                DeclarationWithType* oldRetval = retval;
-                                retval = 0;
-                                if ( ! LinkageSpec::isBuiltin( funcDecl->get_linkage() ) && isLvalueRet( funcDecl->get_functionType() ) ) {
-                                        retval = funcDecl->get_functionType()->get_returnVals().front();
-                                }
-                                // fix expressions and return statements in this function
-                                funcDecl->set_statements( funcDecl->get_statements()->acceptMutator( *this ) );
-                                retval = oldRetval;
-                        } // if
-                        return funcDecl;
-                }
-
-                Type * Pass1::mutate( ReferenceType * refType ) {
+                bool isDeref( Expression * expr ) {
+                        if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
+                                return InitTweak::getFunctionName( untyped ) == "*?";
+                        } else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
+                                if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
+                                        return func->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getFunctionName( appExpr ) == "*?";
+                                }
+                        }
+                        return false;
+                }
+
+                bool isIntrinsicReference( Expression * expr ) {
+                        if ( isDeref( expr ) ) return true;
+                        else if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
+                                return InitTweak::getFunctionName( untyped ) == "?[?]";
+                        } else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
+                                if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
+                                        return func->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getFunctionName( appExpr ) == "?[?]";
+                                }
+                        }
+                        return false;
+                }
+
+                void fixArg( Expression *& arg, Type * formal ) {
+                        // if ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
+                                if ( dynamic_cast<ReferenceType*>( formal ) ) { // xxx - but might be deref, in which case result isn't REALLY a reference, at least not in the sense that we need to add another deref...
+                                        // doesn't work, for some reason left arg is skipped in assign
+                                        ReferenceType * refType = safe_dynamic_cast< ReferenceType * >( arg->get_result() ) ;
+                                        std::cerr << "appexpr arg is non-deref/index intrinsic call" << std::endl;
+                                        std::cerr << arg << std::endl;
+                                        PointerType * ptrType = new PointerType( Type::Qualifiers(), refType->get_base()->clone() );
+                                        delete refType;
+                                        arg->set_result( ptrType );
+                                        arg = UntypedExpr::createDeref( arg );
+                                }
+
+                        // }
+                }
+
+                Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
+                        if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
+                                if ( function->get_linkage() == LinkageSpec::Intrinsic ) { // intrinsic functions that turn pointers into references
+                                        FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
+                                        assertf( ftype, "Function declaration does not have function type." );
+                                        for ( auto p : group_iterate( appExpr->get_args(), ftype->get_parameters() ) ) {
+                                                Expression *& arg = std::get<0>( p );
+                                                DeclarationWithType * formal = std::get<1>( p );
+                                                std::cerr << "pair<0>: " << arg << std::endl;
+                                                std::cerr << "pair<1>: " << formal->get_type() << std::endl;
+                                                if ( isIntrinsicReference( arg ) ) {
+                                                        std::cerr << "skipping intrinsic reference" << std::endl;
+                                                        continue;
+                                                } else {
+                                                        fixArg( arg, formal->get_type() );
+                                                }
+                                        }
+                                }
+                        }
+                        return appExpr;
+                }
+
+                Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
+                        // conversion to reference type
+                        if ( ReferenceType * refType = dynamic_cast< ReferenceType * >( castExpr->get_result() ) ) {
+                                (void)refType;
+                                if ( ReferenceType * otherRef = dynamic_cast< ReferenceType * >( castExpr->get_arg()->get_result() ) ) {
+                                        // nothing to do if casting from reference to reference.
+                                        (void)otherRef;
+                                        std::cerr << "convert reference to reference -- nop" << std::endl;
+                                        if ( isIntrinsicReference( castExpr->get_arg() ) ) {
+                                                Expression * callExpr = castExpr->get_arg();
+                                                Expression ** arg = nullptr;
+                                                Expression *& arg0 = InitTweak::getCallArg( callExpr, 0 );
+                                                if ( dynamic_cast<PointerType *>( arg0->get_result() ) ) {
+                                                        arg = &arg0;
+                                                } else {
+                                                        arg = &InitTweak::getCallArg( callExpr, 1 );
+                                                }
+
+                                                castExpr->set_arg( *arg );
+                                                *arg = castExpr;
+                                                std::cerr << "but arg is deref -- &" << std::endl;
+                                                std::cerr << callExpr << std::endl;
+                                                // castExpr->set_arg( new AddressExpr( castExpr->get_arg() ) );
+
+                                                // move environment out to new top-level
+                                                callExpr->set_env( castExpr->get_env() );
+                                                castExpr->set_env( nullptr );
+                                                return callExpr;
+                                        }
+                                        std::cerr << castExpr << std::endl;
+                                        return castExpr;
+                                } else if ( castExpr->get_arg()->get_result()->get_lvalue() ) {
+                                        // conversion from lvalue to reference
+                                        // xxx - keep cast, but turn into pointer cast??
+                                        // xxx - memory
+                                        std::cerr << "convert lvalue to reference -- &" << std::endl;
+                                        std::cerr << castExpr->get_arg() << std::endl;
+                                        castExpr->set_arg( new AddressExpr( castExpr->get_arg() ) );
+                                        // return new AddressExpr( castExpr->get_arg() );
+                                        return castExpr;
+                                } else {
+                                        // rvalue to reference conversion -- introduce temporary
+                                }
+                                assertf( false, "Only conversions to reference from lvalue are currently supported: %s", toString( castExpr ).c_str() );
+                        } else if ( ReferenceType * refType = dynamic_cast< ReferenceType * >( castExpr->get_arg()->get_result() ) ) {
+                                // should be easy, just need to move deref code up here?
+                                std::cerr << "convert reference to rvalue -- *" << std::endl;
+                                if ( isIntrinsicReference( castExpr->get_arg() ) ) {
+                                        std::cerr << "but arg is intrinsic reference -- nop" << std::endl;
+                                        return castExpr;
+                                }
+                                std::cerr << castExpr << std::endl;
+
+                                PointerType * ptrType = new PointerType( refType->get_qualifiers(), refType->get_base()->clone() );
+                                delete castExpr->get_result();
+                                castExpr->set_result( ptrType );
+                                Expression * deref = UntypedExpr::createDeref( castExpr );
+                                deref->set_env( castExpr->get_env() );
+                                castExpr->set_env( nullptr );
+                                return deref;
+                                // assertf( false, "Conversions from reference types are not currently supported." );
+                        }
+                        return castExpr;
+                }
+
+                Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
                         Type * base = refType->get_base();
                         refType->set_base( nullptr );
@@ -117 +224 @@
                 }
 
-                Expression * Pass1::mutate( VariableExpr *varExpr ) {
-                        if ( ReferenceType * refType = dynamic_cast< ReferenceType * >( varExpr->get_result() ) ) {
-                                varExpr->set_result( refType->acceptMutator( *this ) );
-                                return UntypedExpr::createDeref( varExpr );
-                        }
-                        return Parent::mutate( varExpr );
-                }
-
-                Expression * Pass1::mutate( ApplicationExpr *appExpr ) {
-                        appExpr->get_function()->acceptMutator( *this );
-                        mutateAll( appExpr->get_args(), *this );
-
-                        PointerType *pointer = safe_dynamic_cast< PointerType* >( appExpr->get_function()->get_result() );
-                        FunctionType *function = safe_dynamic_cast< FunctionType* >( pointer->get_base() );
-
-                        Type *funType = isLvalueRet( function );
-                        if ( funType && ! isIntrinsicApp( appExpr ) ) {
-                                Expression *expr = appExpr;
-                                Type *appType = appExpr->get_result();
-                                if ( isPolyType( funType ) && ! isPolyType( appType ) ) {
-                                        // make sure cast for polymorphic type is inside dereference
-                                        expr = new CastExpr( appExpr, new PointerType( Type::Qualifiers(), appType->clone() ) );
-                                }
-                                UntypedExpr *deref = new UntypedExpr( new NameExpr( "*?" ) );
-                                deref->set_result( appType->clone() );
-                                appExpr->set_result( new PointerType( Type::Qualifiers(), appType ) );
-                                deref->get_args().push_back( expr );
-                                return deref;
-                        } else {
-                                return appExpr;
-                        } // if
-                }
-
-                Statement * Pass1::mutate(ReturnStmt *retStmt) {
-                        if ( retval && retStmt->get_expr() ) {
-                                if ( retStmt->get_expr()->get_result()->get_lvalue() ) {
-                                        // ***** Code Removal ***** because casts may be stripped already
-
-                                        // strip casts because not allowed to take address of cast
-                                        // while ( CastExpr *castExpr = dynamic_cast< CastExpr* >( retStmt->get_expr() ) ) {
-                                        //      retStmt->set_expr( castExpr->get_arg() );
-                                        //      retStmt->get_expr()->set_env( castExpr->get_env() );
-                                        //      castExpr->set_env( 0 );
-                                        //      castExpr->set_arg( 0 );
-                                        //      delete castExpr;
-                                        // } // while
-                                        retStmt->set_expr( new AddressExpr( retStmt->get_expr()->acceptMutator( *this ) ) );
-                                } else {
-                                        throw SemanticError( "Attempt to return non-lvalue from an lvalue-qualified function" );
-                                } // if
-                        } // if
-                        return retStmt;
-                }
-
-                void Pass2::visit( FunctionType *funType ) {
-                        std::string typeName;
-                        if ( isLvalueRet( funType ) ) {
-                                DeclarationWithType *retParm = funType->get_returnVals().front();
-
-                                // make a new parameter that is a pointer to the type of the old return value
-                                retParm->set_type( new PointerType( Type::Qualifiers(), retParm->get_type() ) );
-                        } // if
-
-                        Visitor::visit( funType );
-                }
-
-                bool isDeref( Expression * expr ) {
-                        if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
-                                return InitTweak::getFunctionName( untyped ) == "*?";
-                        } else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
-                                return InitTweak::getFunctionName( appExpr ) == "*?";
-                        } else {
-                                return false;
-                        }
-                }
-
-                Expression * GeneralizedLvalue::mutate( AddressExpr * addrExpr ) {
-                        addrExpr = safe_dynamic_cast< AddressExpr * >( Parent::mutate( addrExpr ) );
+                Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
                         if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( addrExpr->get_arg() ) ) {
                                 Expression * arg1 = commaExpr->get_arg1()->clone();
@@ -206 +236 @@
                                 delete addrExpr;
                                 return new ConditionalExpr( arg1, new AddressExpr( arg2 ), new AddressExpr( arg3 ) );
-                        } else if ( isDeref( addrExpr->get_arg() ) ) {
-                                // xxx - this doesn't belong here -- move it somewhere else
-                                Expression *& arg = InitTweak::getCallArg( addrExpr->get_arg(), 0 );
-                                Expression * inner = arg;
-                                arg = nullptr;
-                                delete addrExpr;
-                                return inner;
                         }
                         return addrExpr;