source: src/ResolvExpr/Resolver.cc @ 8d722cc

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Resolver.cc --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 12:17:01 2015
// Last Modified By : Andrew Beach
// Last Modified On : Tus Aug  8 16:06:00 2017
// Update Count     : 212
//

#include <stddef.h>                      // for NULL
#include <cassert>                       // for strict_dynamic_cast, assert
#include <memory>                        // for allocator, allocator_traits<...
#include <tuple>                         // for get

#include "Alternative.h"                 // for Alternative, AltList
#include "AlternativeFinder.h"           // for AlternativeFinder, resolveIn...
#include "Common/PassVisitor.h"          // for PassVisitor
#include "Common/SemanticError.h"        // for SemanticError
#include "Common/utility.h"              // for ValueGuard, group_iterate
#include "CurrentObject.h"               // for CurrentObject
#include "InitTweak/InitTweak.h"         // for isIntrinsicSingleArgCallStmt
#include "RenameVars.h"                  // for RenameVars, global_renamer
#include "ResolvExpr/TypeEnvironment.h"  // for TypeEnvironment
#include "ResolveTypeof.h"               // for resolveTypeof
#include "Resolver.h"
#include "SymTab/Autogen.h"              // for SizeType
#include "SymTab/Indexer.h"              // for Indexer
#include "SynTree/Declaration.h"         // for ObjectDecl, TypeDecl, Declar...
#include "SynTree/Expression.h"          // for Expression, CastExpr, InitExpr
#include "SynTree/Initializer.h"         // for ConstructorInit, SingleInit
#include "SynTree/Statement.h"           // for ForStmt, Statement, BranchStmt
#include "SynTree/Type.h"                // for Type, BasicType, PointerType
#include "SynTree/TypeSubstitution.h"    // for TypeSubstitution
#include "SynTree/Visitor.h"             // for acceptAll, maybeAccept
#include "typeops.h"                     // for extractResultType

using namespace std;

namespace ResolvExpr {
        struct Resolver final : public WithIndexer, public WithGuards, public WithVisitorRef<Resolver>, public WithShortCircuiting {
                Resolver() {}
                Resolver( const SymTab::Indexer & other ) {
                        indexer = other;
                }

                void previsit( FunctionDecl *functionDecl );
                void postvisit( FunctionDecl *functionDecl );
                void previsit( ObjectDecl *functionDecl );
                void previsit( TypeDecl *typeDecl );
                void previsit( EnumDecl * enumDecl );

                void previsit( ArrayType * at );
                void previsit( PointerType * at );

                void previsit( ExprStmt *exprStmt );
                void previsit( AsmExpr *asmExpr );
                void previsit( AsmStmt *asmStmt );
                void previsit( IfStmt *ifStmt );
                void previsit( WhileStmt *whileStmt );
                void previsit( ForStmt *forStmt );
                void previsit( SwitchStmt *switchStmt );
                void previsit( CaseStmt *caseStmt );
                void previsit( BranchStmt *branchStmt );
                void previsit( ReturnStmt *returnStmt );
                void previsit( ThrowStmt *throwStmt );
                void previsit( CatchStmt *catchStmt );

                void previsit( SingleInit *singleInit );
                void previsit( ListInit *listInit );
                void previsit( ConstructorInit *ctorInit );
          private:
        typedef std::list< Initializer * >::iterator InitIterator;

                template< typename PtrType >
                void handlePtrType( PtrType * type );

          void resolveAggrInit( ReferenceToType *, InitIterator &, InitIterator & );
          void resolveSingleAggrInit( Declaration *, InitIterator &, InitIterator &, TypeSubstitution sub );
          void fallbackInit( ConstructorInit * ctorInit );

                Type * functionReturn = nullptr;
                CurrentObject currentObject = nullptr;
                bool inEnumDecl = false;
        };

        void resolve( std::list< Declaration * > translationUnit ) {
                PassVisitor<Resolver> resolver;
                acceptAll( translationUnit, resolver );
        }

        // used in resolveTypeof
        Expression *resolveInVoidContext( Expression *expr, const SymTab::Indexer &indexer ) {
                TypeEnvironment env;
                return resolveInVoidContext( expr, indexer, env );
        }

        namespace {
                void finishExpr( Expression *expr, const TypeEnvironment &env ) {
                        expr->set_env( new TypeSubstitution );
                        env.makeSubstitution( *expr->get_env() );
                }
        } // namespace

        Expression *findVoidExpression( Expression *untyped, const SymTab::Indexer &indexer ) {
                global_renamer.reset();
                TypeEnvironment env;
                Expression *newExpr = resolveInVoidContext( untyped, indexer, env );
                finishExpr( newExpr, env );
                return newExpr;
        }

        namespace {
                Expression *findSingleExpression( Expression *untyped, const SymTab::Indexer &indexer ) {
                        TypeEnvironment env;
                        AlternativeFinder finder( indexer, env );
                        finder.find( untyped );
#if 0
                        if ( finder.get_alternatives().size() != 1 ) {
                                std::cout << "untyped expr is ";
                                untyped->print( std::cout );
                                std::cout << std::endl << "alternatives are:";
                                for ( std::list< Alternative >::const_iterator i = finder.get_alternatives().begin(); i != finder.get_alternatives().end(); ++i ) {
                                        i->print( std::cout );
                                } // for
                        } // if
#endif
                        assertf( finder.get_alternatives().size() == 1, "findSingleExpression: must have exactly one alternative at the end." );
                        Alternative &choice = finder.get_alternatives().front();
                        Expression *newExpr = choice.expr->clone();
                        finishExpr( newExpr, choice.env );
                        return newExpr;
                }

                bool isIntegralType( Type *type ) {
                        if ( dynamic_cast< EnumInstType * >( type ) ) {
                                return true;
                        } else if ( BasicType *bt = dynamic_cast< BasicType * >( type ) ) {
                                return bt->isInteger();
                        } else if ( dynamic_cast< ZeroType* >( type ) != nullptr || dynamic_cast< OneType* >( type ) != nullptr ) {
                                return true;
                        } else {
                                return false;
                        } // if
                }

                Expression *findIntegralExpression( Expression *untyped, const SymTab::Indexer &indexer ) {
                        TypeEnvironment env;
                        AlternativeFinder finder( indexer, env );
                        finder.find( untyped );
#if 0
                        if ( finder.get_alternatives().size() != 1 ) {
                                std::cout << "untyped expr is ";
                                untyped->print( std::cout );
                                std::cout << std::endl << "alternatives are:";
                                for ( std::list< Alternative >::const_iterator i = finder.get_alternatives().begin(); i != finder.get_alternatives().end(); ++i ) {
                                        i->print( std::cout );
                                } // for
                        } // if
#endif
                        Expression *newExpr = 0;
                        const TypeEnvironment *newEnv = 0;
                        for ( AltList::const_iterator i = finder.get_alternatives().begin(); i != finder.get_alternatives().end(); ++i ) {
                                if ( i->expr->get_result()->size() == 1 && isIntegralType( i->expr->get_result() ) ) {
                                        if ( newExpr ) {
                                                throw SemanticError( "Too many interpretations for case control expression", untyped );
                                        } else {
                                                newExpr = i->expr->clone();
                                                newEnv = &i->env;
                                        } // if
                                } // if
                        } // for
                        if ( ! newExpr ) {
                                throw SemanticError( "No interpretations for case control expression", untyped );
                        } // if
                        finishExpr( newExpr, *newEnv );
                        return newExpr;
                }

        }

        void Resolver::previsit( ObjectDecl *objectDecl ) {
                Type *new_type = resolveTypeof( objectDecl->get_type(), indexer );
                objectDecl->set_type( new_type );
                // To handle initialization of routine pointers, e.g., int (*fp)(int) = foo(), means that class-variable
                // initContext is changed multiple time because the LHS is analysed twice. The second analysis changes
                // initContext because of a function type can contain object declarations in the return and parameter types. So
                // each value of initContext is retained, so the type on the first analysis is preserved and used for selecting
                // the RHS.
                GuardValue( currentObject );
                currentObject = CurrentObject( objectDecl->get_type() );
                if ( inEnumDecl && dynamic_cast< EnumInstType * >( objectDecl->get_type() ) ) {
                        // enumerator initializers should not use the enum type to initialize, since
                        // the enum type is still incomplete at this point. Use signed int instead.
                        currentObject = CurrentObject( new BasicType( Type::Qualifiers(), BasicType::SignedInt ) );
                }
        }

        template< typename PtrType >
        void Resolver::handlePtrType( PtrType * type ) {
                if ( type->get_dimension() ) {
                        CastExpr *castExpr = new CastExpr( type->get_dimension(), SymTab::SizeType->clone() );
                        Expression *newExpr = findSingleExpression( castExpr, indexer );
                        delete type->get_dimension();
                        type->set_dimension( newExpr );
                }
        }

        void Resolver::previsit( ArrayType * at ) {
                handlePtrType( at );
        }

        void Resolver::previsit( PointerType * pt ) {
                handlePtrType( pt );
        }

        void Resolver::previsit( TypeDecl *typeDecl ) {
                if ( typeDecl->get_base() ) {
                        Type *new_type = resolveTypeof( typeDecl->get_base(), indexer );
                        typeDecl->set_base( new_type );
                } // if
        }

        void Resolver::previsit( FunctionDecl *functionDecl ) {
#if 0
                std::cerr << "resolver visiting functiondecl ";
                functionDecl->print( std::cerr );
                std::cerr << std::endl;
#endif
                Type *new_type = resolveTypeof( functionDecl->get_type(), indexer );
                functionDecl->set_type( new_type );
                GuardValue( functionReturn );
                functionReturn = ResolvExpr::extractResultType( functionDecl->get_functionType() );
        }


        void Resolver::postvisit( FunctionDecl *functionDecl ) {
                // default value expressions have an environment which shouldn't be there and trips up later passes.
                // xxx - it might be necessary to somehow keep the information from this environment, but I can't currently
                // see how it's useful.
                for ( Declaration * d : functionDecl->get_functionType()->get_parameters() ) {
                        if ( ObjectDecl * obj = dynamic_cast< ObjectDecl * >( d ) ) {
                                if ( SingleInit * init = dynamic_cast< SingleInit * >( obj->get_init() ) ) {
                                        delete init->get_value()->get_env();
                                        init->get_value()->set_env( nullptr );
                                }
                        }
                }
        }

        void Resolver::previsit( EnumDecl * ) {
                // in case we decide to allow nested enums
                GuardValue( inEnumDecl );
                inEnumDecl = true;
        }

        void Resolver::previsit( ExprStmt *exprStmt ) {
                visit_children = false;
                assertf( exprStmt->get_expr(), "ExprStmt has null Expression in resolver" );
                Expression *newExpr = findVoidExpression( exprStmt->get_expr(), indexer );
                delete exprStmt->get_expr();
                exprStmt->set_expr( newExpr );
        }

        void Resolver::previsit( AsmExpr *asmExpr ) {
                visit_children = false;
                Expression *newExpr = findVoidExpression( asmExpr->get_operand(), indexer );
                delete asmExpr->get_operand();
                asmExpr->set_operand( newExpr );
                if ( asmExpr->get_inout() ) {
                        newExpr = findVoidExpression( asmExpr->get_inout(), indexer );
                        delete asmExpr->get_inout();
                        asmExpr->set_inout( newExpr );
                } // if
        }

        void Resolver::previsit( AsmStmt *asmStmt ) {
                visit_children = false;
                acceptAll( asmStmt->get_input(), *visitor );
                acceptAll( asmStmt->get_output(), *visitor );
        }

        void Resolver::previsit( IfStmt *ifStmt ) {
                Expression *newExpr = findSingleExpression( ifStmt->get_condition(), indexer );
                delete ifStmt->get_condition();
                ifStmt->set_condition( newExpr );
        }

        void Resolver::previsit( WhileStmt *whileStmt ) {
                Expression *newExpr = findSingleExpression( whileStmt->get_condition(), indexer );
                delete whileStmt->get_condition();
                whileStmt->set_condition( newExpr );
        }

        void Resolver::previsit( ForStmt *forStmt ) {
                if ( forStmt->get_condition() ) {
                        Expression * newExpr = findSingleExpression( forStmt->get_condition(), indexer );
                        delete forStmt->get_condition();
                        forStmt->set_condition( newExpr );
                } // if

                if ( forStmt->get_increment() ) {
                        Expression * newExpr = findVoidExpression( forStmt->get_increment(), indexer );
                        delete forStmt->get_increment();
                        forStmt->set_increment( newExpr );
                } // if
        }

        void Resolver::previsit( SwitchStmt *switchStmt ) {
                GuardValue( currentObject );
                Expression *newExpr;
                newExpr = findIntegralExpression( switchStmt->get_condition(), indexer );
                delete switchStmt->get_condition();
                switchStmt->set_condition( newExpr );

                currentObject = CurrentObject( newExpr->get_result() );
        }

        void Resolver::previsit( CaseStmt *caseStmt ) {
                if ( caseStmt->get_condition() ) {
                        std::list< InitAlternative > initAlts = currentObject.getOptions();
                        assertf( initAlts.size() == 1, "SwitchStmt did not correctly resolve an integral expression." );
                        CastExpr * castExpr = new CastExpr( caseStmt->get_condition(), initAlts.front().type->clone() );
                        Expression * newExpr = findSingleExpression( castExpr, indexer );
                        castExpr = strict_dynamic_cast< CastExpr * >( newExpr );
                        caseStmt->set_condition( castExpr->get_arg() );
                        castExpr->set_arg( nullptr );
                        delete castExpr;
                }
        }

        void Resolver::previsit( BranchStmt *branchStmt ) {
                visit_children = false;
                // must resolve the argument for a computed goto
                if ( branchStmt->get_type() == BranchStmt::Goto ) { // check for computed goto statement
                        if ( Expression * arg = branchStmt->get_computedTarget() ) {
                                VoidType v = Type::Qualifiers();                // cast to void * for the alternative finder
                                PointerType pt( Type::Qualifiers(), v.clone() );
                                CastExpr * castExpr = new CastExpr( arg, pt.clone() );
                                Expression * newExpr = findSingleExpression( castExpr, indexer ); // find best expression
                                branchStmt->set_target( newExpr );
                        } // if
                } // if
        }

        void Resolver::previsit( ReturnStmt *returnStmt ) {
                visit_children = false;
                if ( returnStmt->get_expr() ) {
                        CastExpr *castExpr = new CastExpr( returnStmt->get_expr(), functionReturn->clone() );
                        Expression *newExpr = findSingleExpression( castExpr, indexer );
                        delete castExpr;
                        returnStmt->set_expr( newExpr );
                } // if
        }

        void Resolver::previsit( ThrowStmt *throwStmt ) {
                visit_children = false;
                // TODO: Replace *exception type with &exception type.
                if ( throwStmt->get_expr() ) {
                        StructDecl * exception_decl =
                                indexer.lookupStruct( "__cfaehm__base_exception_t" );
                        assert( exception_decl );
                        Expression * wrapped = new CastExpr(
                                throwStmt->get_expr(),
                                new PointerType(
                                        noQualifiers,
                                        new StructInstType(
                                                noQualifiers,
                                                exception_decl
                                                )
                                        )
                                );
                        Expression * newExpr = findSingleExpression( wrapped, indexer );
                        throwStmt->set_expr( newExpr );
                }
        }

        void Resolver::previsit( CatchStmt *catchStmt ) {
                if ( catchStmt->get_cond() ) {
                        Expression * wrapped = new CastExpr(
                                catchStmt->get_cond(),
                                new BasicType( noQualifiers, BasicType::Bool )
                                );
                        catchStmt->set_cond( findSingleExpression( wrapped, indexer ) );
                }
        }

        template< typename T >
        bool isCharType( T t ) {
                if ( BasicType * bt = dynamic_cast< BasicType * >( t ) ) {
                        return bt->get_kind() == BasicType::Char || bt->get_kind() == BasicType::SignedChar ||
                                bt->get_kind() == BasicType::UnsignedChar;
                }
                return false;
        }

        void Resolver::previsit( SingleInit *singleInit ) {
                visit_children = false;
                // resolve initialization using the possibilities as determined by the currentObject cursor
                UntypedInitExpr * untyped = new UntypedInitExpr( singleInit->get_value(), currentObject.getOptions() );
                Expression * newExpr = findSingleExpression( untyped, indexer );
                InitExpr * initExpr = strict_dynamic_cast< InitExpr * >( newExpr );

                // move cursor to the object that is actually initialized
                currentObject.setNext( initExpr->get_designation() );

                // discard InitExpr wrapper and retain relevant pieces
                newExpr = initExpr->get_expr();
                newExpr->set_env( initExpr->get_env() );
                initExpr->set_expr( nullptr );
                initExpr->set_env( nullptr );
                delete initExpr;

                // get the actual object's type (may not exactly match what comes back from the resolver due to conversions)
                Type * initContext = currentObject.getCurrentType();

                // check if actual object's type is char[]
                if ( ArrayType * at = dynamic_cast< ArrayType * >( initContext ) ) {
                        if ( isCharType( at->get_base() ) ) {
                                // check if the resolved type is char *
                                if ( PointerType * pt = dynamic_cast< PointerType *>( newExpr->get_result() ) ) {
                                        if ( isCharType( pt->get_base() ) ) {
                                                // strip cast if we're initializing a char[] with a char *, e.g.  char x[] = "hello";
                                                CastExpr *ce = strict_dynamic_cast< CastExpr * >( newExpr );
                                                newExpr = ce->get_arg();
                                                ce->set_arg( nullptr );
                                                delete ce;
                                        }
                                }
                        }
                }

                // set initializer expr to resolved express
                singleInit->set_value( newExpr );

                // move cursor to next object in preparation for next initializer
                currentObject.increment();
        }

        void Resolver::previsit( ListInit * listInit ) {
                visit_children = false;
                // move cursor into brace-enclosed initializer-list
                currentObject.enterListInit();
                // xxx - fix this so that the list isn't copied, iterator should be used to change current element
                std::list<Designation *> newDesignations;
                for ( auto p : group_iterate(listInit->get_designations(), listInit->get_initializers()) ) {
                        // iterate designations and initializers in pairs, moving the cursor to the current designated object and resolving
                        // the initializer against that object.
                        Designation * des = std::get<0>(p);
                        Initializer * init = std::get<1>(p);
                        newDesignations.push_back( currentObject.findNext( des ) );
                        init->accept( *visitor );
                }
                // set the set of 'resolved' designations and leave the brace-enclosed initializer-list
                listInit->get_designations() = newDesignations; // xxx - memory management
                currentObject.exitListInit();

                // xxx - this part has not be folded into CurrentObject yet
                // } else if ( TypeInstType * tt = dynamic_cast< TypeInstType * >( initContext ) ) {
                //      Type * base = tt->get_baseType()->get_base();
                //      if ( base ) {
                //              // know the implementation type, so try using that as the initContext
                //              ObjectDecl tmpObj( "", Type::StorageClasses(), LinkageSpec::Cforall, nullptr, base->clone(), nullptr );
                //              currentObject = &tmpObj;
                //              visit( listInit );
                //      } else {
                //              // missing implementation type -- might be an unknown type variable, so try proceeding with the current init context
                //              Parent::visit( listInit );
                //      }
                // } else {
        }

        // ConstructorInit - fall back on C-style initializer
        void Resolver::fallbackInit( ConstructorInit * ctorInit ) {
                // could not find valid constructor, or found an intrinsic constructor
                // fall back on C-style initializer
                delete ctorInit->get_ctor();
                ctorInit->set_ctor( NULL );
                delete ctorInit->get_dtor();
                ctorInit->set_dtor( NULL );
                maybeAccept( ctorInit->get_init(), *visitor );
        }

        // needs to be callable from outside the resolver, so this is a standalone function
        void resolveCtorInit( ConstructorInit * ctorInit, const SymTab::Indexer & indexer ) {
                assert( ctorInit );
                PassVisitor<Resolver> resolver( indexer );
                ctorInit->accept( resolver );
        }

        void resolveStmtExpr( StmtExpr * stmtExpr, const SymTab::Indexer & indexer ) {
                assert( stmtExpr );
                PassVisitor<Resolver> resolver( indexer );
                stmtExpr->accept( resolver );
        }

        void Resolver::previsit( ConstructorInit *ctorInit ) {
                visit_children = false;
                // xxx - fallback init has been removed => remove fallbackInit function and remove complexity from FixInit and remove C-init from ConstructorInit
                maybeAccept( ctorInit->get_ctor(), *visitor );
                maybeAccept( ctorInit->get_dtor(), *visitor );

                // found a constructor - can get rid of C-style initializer
                delete ctorInit->get_init();
                ctorInit->set_init( NULL );

                // intrinsic single parameter constructors and destructors do nothing. Since this was
                // implicitly generated, there's no way for it to have side effects, so get rid of it
                // to clean up generated code.
                if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->get_ctor() ) ) {
                        delete ctorInit->get_ctor();
                        ctorInit->set_ctor( NULL );
                }

                if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->get_dtor() ) ) {
                        delete ctorInit->get_dtor();
                        ctorInit->set_dtor( NULL );
                }

                // xxx - todo -- what about arrays?
                // if ( dtor == NULL && InitTweak::isIntrinsicCallStmt( ctorInit->get_ctor() ) ) {
                //      // can reduce the constructor down to a SingleInit using the
                //      // second argument from the ctor call, since
                //      delete ctorInit->get_ctor();
                //      ctorInit->set_ctor( NULL );

                //      Expression * arg =
                //      ctorInit->set_init( new SingleInit( arg ) );
                // }
        }
} // namespace ResolvExpr

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //