Changeset c6b4432 for src/Virtual/ExpandCasts.cc

Timestamp:

Nov 8, 2023, 2:01:11 PM (8 months ago)

Author:

Andrew Beach <ajbeach@…>

Branches:

master

Children:

3e4bf0d, f5ec35a

Parents:

790d835

Message:

Remove BaseSyntaxNode? and clean-up.

File:

• src/Virtual/ExpandCasts.cc (modified) (4 diffs)

src/Virtual/ExpandCasts.cc

@@ -24 +24 @@
 #include "AST/Expr.hpp"
 #include "AST/Pass.hpp"
-#include "Common/PassVisitor.h"    // for PassVisitor
 #include "Common/ScopedMap.h"      // for ScopedMap
 #include "Common/SemanticError.h"  // for SemanticError
 #include "SymTab/Mangler.h"        // for mangleType
-#include "SynTree/Declaration.h"   // for ObjectDecl, StructDecl, FunctionDecl
-#include "SynTree/Expression.h"    // for VirtualCastExpr, CastExpr, Address...
-#include "SynTree/Mutator.h"       // for mutateAll
-#include "SynTree/Type.h"          // for Type, PointerType, StructInstType
-#include "SynTree/Visitor.h"       // for acceptAll
 
 namespace Virtual {
@@ -43 +37 @@
 }
 
-bool is_type_id_object( const ObjectDecl * objectDecl ) {
-        const std::string & objectName = objectDecl->name;
-        return is_prefix( "__cfatid_", objectName );
-}
-
 bool is_type_id_object( const ast::ObjectDecl * decl ) {
         return is_prefix( "__cfatid_", decl->name );
@@ -55 +44 @@
 
         /// Maps virtual table types the instance for that type.
-        class VirtualTableMap final {
-                ScopedMap<std::string, ObjectDecl *> vtable_instances;
-        public:
-                void enterScope() {
-                        vtable_instances.beginScope();
-                }
-                void leaveScope() {
-                        vtable_instances.endScope();
-                }
-
-                ObjectDecl * insert( ObjectDecl * vtableDecl ) {
-                        std::string const & mangledName = SymTab::Mangler::mangleType( vtableDecl->type );
-                        ObjectDecl *& value = vtable_instances[ mangledName ];
-                        if ( value ) {
-                                if ( vtableDecl->storageClasses.is_extern ) {
-                                        return nullptr;
-                                } else if ( ! value->storageClasses.is_extern ) {
-                                        return value;
-                                }
-                        }
-                        value = vtableDecl;
-                        return nullptr;
-                }
-
-                ObjectDecl * lookup( const Type * vtableType ) {
-                        std::string const & mangledName = SymTab::Mangler::mangleType( vtableType );
-                        const auto it = vtable_instances.find( mangledName );
-                        return ( vtable_instances.end() == it ) ? nullptr : it->second;
-                }
-        };
-
-        class VirtualCastCore {
-                CastExpr * cast_to_type_id( Expression * expr, int level_of_indirection ) {
-                        Type * type = new StructInstType(
-                                Type::Qualifiers( Type::Const ), pvt_decl );
-                        for (int i = 0 ; i < level_of_indirection ; ++i) {
-                                type = new PointerType( noQualifiers, type );
-                        }
-                        return new CastExpr( expr, type );
-                }
-
-        public:
-                VirtualCastCore() :
-                        indexer(), vcast_decl( nullptr ), pvt_decl( nullptr )
-                {}
-
-                void premutate( FunctionDecl * functionDecl );
-                void premutate( StructDecl * structDecl );
-                void premutate( ObjectDecl * objectDecl );
-
-                Expression * postmutate( VirtualCastExpr * castExpr );
-
-                VirtualTableMap indexer;
-        private:
-                FunctionDecl *vcast_decl;
-                StructDecl *pvt_decl;
-        };
-
-        void VirtualCastCore::premutate( FunctionDecl * functionDecl ) {
-                if ( (! vcast_decl) &&
-                     functionDecl->get_name() == "__cfavir_virtual_cast" ) {
-                        vcast_decl = functionDecl;
-                }
-        }
-
-        void VirtualCastCore::premutate( StructDecl * structDecl ) {
-                if ( pvt_decl || ! structDecl->has_body() ) {
-                        return;
-                } else if ( structDecl->get_name() == "__cfavir_type_info" ) {
-                        pvt_decl = structDecl;
-                }
-        }
-
-        void VirtualCastCore::premutate( ObjectDecl * objectDecl ) {
-                if ( is_type_id_object( objectDecl ) ) {
-                        // Multiple definitions should be fine because of linkonce.
-                        indexer.insert( objectDecl );
-                }
-        }
-
-        /// Better error locations for generated casts.
-        CodeLocation castLocation( const VirtualCastExpr * castExpr ) {
-                if ( castExpr->location.isSet() ) {
-                        return castExpr->location;
-                } else if ( castExpr->arg->location.isSet() ) {
-                        return castExpr->arg->location;
-                } else if ( castExpr->result->location.isSet() ) {
-                        return castExpr->result->location;
-                } else {
-                        return CodeLocation();
-                }
-        }
-
-        [[noreturn]] void castError( const VirtualCastExpr * castExpr, std::string const & message ) {
-                SemanticError( castLocation( castExpr ), message );
-        }
-
-        /// Get the base type from a pointer or reference.
-        const Type * getBaseType( const Type * type ) {
-                if ( auto target = dynamic_cast<const PointerType *>( type ) ) {
-                        return target->base;
-                } else if ( auto target = dynamic_cast<const ReferenceType *>( type ) ) {
-                        return target->base;
-                } else {
-                        return nullptr;
-                }
-        }
-
-        /* Attempt to follow the "head" field of the structure to get the...
-         * Returns nullptr on error, otherwise owner must free returned node.
-         */
-        StructInstType * followHeadPointerType(
-                        const StructInstType * oldType,
-                        const std::string& fieldName,
-                        const CodeLocation& errorLocation ) {
-
-                // First section of the function is all about trying to fill this variable in.
-                StructInstType * newType = nullptr;
-                {
-                        const StructDecl * oldDecl = oldType->baseStruct;
-                        assert( oldDecl );
-
-                        // Helper function for throwing semantic errors.
-                        auto throwError = [&fieldName, &errorLocation, &oldDecl](const std::string& message) {
-                                const std::string& context = "While following head pointer of " +
-                                        oldDecl->name + " named '" + fieldName + "': ";
-                                SemanticError( errorLocation, context + message );
-                        };
-
-                        if ( oldDecl->members.empty() ) {
-                                throwError( "Type has no fields." );
-                        }
-                        const Declaration * memberDecl = oldDecl->members.front();
-                        assert( memberDecl );
-                        const ObjectDecl * fieldDecl = dynamic_cast<const ObjectDecl *>( memberDecl );
-                        assert( fieldDecl );
-                        if ( fieldName != fieldDecl->name ) {
-                                throwError( "Head field did not have expected name." );
-                        }
-
-                        const Type * fieldType = fieldDecl->type;
-                        if ( nullptr == fieldType ) {
-                                throwError( "Could not get head field." );
-                        }
-                        const PointerType * ptrType = dynamic_cast<const PointerType *>( fieldType );
-                        if ( nullptr == ptrType ) {
-                                throwError( "First field is not a pointer type." );
-                        }
-                        assert( ptrType->base );
-                        newType = dynamic_cast<StructInstType *>( ptrType->base );
-                        if ( nullptr == newType ) {
-                                throwError( "First field does not point to a structure type." );
-                        }
-                }
-
-                // Now we can look into copying it.
-                newType = newType->clone();
-                if ( ! oldType->parameters.empty() ) {
-                        deleteAll( newType->parameters );
-                        newType->parameters.clear();
-                        cloneAll( oldType->parameters, newType->parameters );
-                }
-                return newType;
-        }
-
-        /// Get the type-id type from a virtual type.
-        StructInstType * getTypeIdType( const Type * type, const CodeLocation& errorLocation ) {
-                const StructInstType * typeInst = dynamic_cast<const StructInstType *>( type );
-                if ( nullptr == typeInst ) {
-                        return nullptr;
-                }
-                StructInstType * tableInst =
-                        followHeadPointerType( typeInst, "virtual_table", errorLocation );
-                if ( nullptr == tableInst ) {
-                        return nullptr;
-                }
-                StructInstType * typeIdInst =
-                        followHeadPointerType( tableInst, "__cfavir_typeid", errorLocation );
-                delete tableInst;
-                return typeIdInst;
-        }
-
-        Expression * VirtualCastCore::postmutate( VirtualCastExpr * castExpr ) {
-                assertf( castExpr->result, "Virtual Cast target not found before expansion." );
-
-                assert( vcast_decl );
-                assert( pvt_decl );
-
-                const Type * base_type = getBaseType( castExpr->result );
-                if ( nullptr == base_type ) {
-                        castError( castExpr, "Virtual cast target must be a pointer or reference type." );
-                }
-                const Type * type_id_type = getTypeIdType( base_type, castLocation( castExpr ) );
-                if ( nullptr == type_id_type ) {
-                        castError( castExpr, "Ill formed virtual cast target type." );
-                }
-                ObjectDecl * type_id = indexer.lookup( type_id_type );
-                delete type_id_type;
-                if ( nullptr == type_id ) {
-                        castError( castExpr, "Virtual cast does not target a virtual type." );
-                }
-
-                Expression * result = new CastExpr(
-                        new ApplicationExpr( VariableExpr::functionPointer( vcast_decl ), {
-                                cast_to_type_id( new AddressExpr( new VariableExpr( type_id ) ), 1 ),
-                                cast_to_type_id( castExpr->get_arg(), 2 ),
-                        } ),
-                        castExpr->get_result()->clone()
-                );
-
-                castExpr->set_arg( nullptr );
-                castExpr->set_result( nullptr );
-                delete castExpr;
-                return result;
-        }
 
 /// Better error locations for generated casts.
@@ -494 +268 @@
 } // namespace
 
-void expandCasts( std::list< Declaration * > & translationUnit ) {
-        PassVisitor<VirtualCastCore> translator;
-        mutateAll( translationUnit, translator );
-}
-
 void expandCasts( ast::TranslationUnit & translationUnit ) {
         ast::Pass<ExpandCastsCore>::run( translationUnit );