source: src/ResolvExpr/CurrentObject.cpp @ 1725989

//
// 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.
//
// CurrentObject.cpp --
//
// Author           : Rob Schluntz
// Created On       : Tue Jun 13 15:28:32 2017
// Last Modified By : Peter A. Buhr
// Last Modified On : Sat Dec  9 17:49:51 2023
// Update Count     : 20
//

#include "CurrentObject.hpp"

#include <stddef.h>                    // for size_t
#include <cassert>                     // for assertf, assert, safe_dynamic_...
#include <deque>
#include <iostream>                    // for ostream, operator<<, basic_ost...
#include <stack>                       // for stack
#include <string>                      // for string, operator<<, allocator

#include "AST/Copy.hpp"                // for shallowCopy
#include "AST/Expr.hpp"                // for InitAlternative
#include "AST/GenericSubstitution.hpp" // for genericSubstitution
#include "AST/Init.hpp"                // for Designation
#include "AST/Node.hpp"                // for readonly
#include "AST/Print.hpp"               // for readonly
#include "AST/Type.hpp"
#include "Common/Eval.hpp"             // for eval
#include "Common/Indenter.hpp"         // for Indenter, operator<<
#include "Common/SemanticError.hpp"    // for SemanticError
#include "Common/Utility.hpp"          // for toString

#if 0
#define PRINT(x) x
#else
#define PRINT(x)
#endif

namespace ast {

/// Iterates members of a type by initializer.
class MemberIterator {
public:
        virtual ~MemberIterator() {}

        /// Internal set position based on iterator ranges.
        virtual void setPosition(
                std::deque< ptr< Expr > >::const_iterator it,
                std::deque< ptr< Expr > >::const_iterator end ) = 0;

        /// Walks the current object using the given designators as a guide.
        void setPosition( const std::deque< ptr< Expr > > & designators ) {
                setPosition( designators.begin(), designators.end() );
        }

        /// Retrieve the list of possible (Type,Designation) pairs for the
        /// current position in the current object.
        virtual std::deque< InitAlternative > operator* () const = 0;

        /// True if the iterator is not currently at the end.
        virtual operator bool() const = 0;

        /// Moves the iterator by one member in the current object.
        virtual MemberIterator & bigStep() = 0;

        /// Moves the iterator by one member in the current subobject.
        virtual MemberIterator & smallStep() = 0;

        /// The type of the current object.
        virtual const Type * getType() = 0;

        /// The type of the current subobject.
        virtual const Type * getNext() = 0;

        /// Helper for operator*; aggregates must add designator to each init
        /// alternative, but adding designators in operator* creates duplicates.
        virtual std::deque< InitAlternative > first() const = 0;
};

namespace {

/// create a new MemberIterator that traverses a type correctly
MemberIterator * createMemberIterator( const CodeLocation & loc, const Type * type );

/// Iterates "other" types (e.g. basic, pointer) which do not change at list initializer entry
class SimpleIterator final : public MemberIterator {
        CodeLocation location;
        const Type * type = nullptr;
public:
        SimpleIterator( const CodeLocation & loc, const Type * t ) : location( loc ), type( t ) {}

        void setPosition(
                std::deque< ptr< Expr > >::const_iterator begin,
                std::deque< ptr< Expr > >::const_iterator end
        ) override {
                if ( begin != end ) {
                        SemanticError( location, "Un-designated initializer given non-empty designator" );
                }
        }

        std::deque< InitAlternative > operator* () const override { return first(); }

        operator bool() const override { return type; }

        SimpleIterator & bigStep() override { return smallStep(); }
        SimpleIterator & smallStep() override {
                type = nullptr;  // empty on increment because no members
                return *this;
        }

        const Type * getType() override { return type; }

        const Type * getNext() override { return type; }

        std::deque< InitAlternative > first() const override {
                if ( type ) return { InitAlternative{ type, new Designation{ location } } };
                return {};
        }
};

/// Iterates over an indexed type:
class IndexIterator : public MemberIterator {
protected:
        CodeLocation location;
        size_t index = 0;
        size_t size = 0;
        std::unique_ptr<MemberIterator> memberIter;
public:
        IndexIterator( const CodeLocation & loc, size_t size ) :
                location( loc ), size( size )
        {}

        void setPosition( const Expr * expr ) {
                // need to permit integer-constant-expressions, including: integer constants,
                // enumeration constants, character constants, sizeof expressions, alignof expressions,
                // cast expressions

                auto arg = eval( expr );
                assertf( arg.hasKnownValue, "Non-evaluable expression made it to IndexIterator" );
                index = arg.knownValue;

                // if ( auto constExpr = dynamic_cast< const ConstantExpr * >( expr ) ) {
                //      try {
                //              index = constExpr->intValue();
                //      } catch ( SemanticErrorException & ) {
                //              SemanticError( expr, "Constant expression of non-integral type in array designator: " );
                //      }
                // } else if ( auto castExpr = dynamic_cast< const CastExpr * >( expr ) ) {
                //      setPosition( castExpr->arg );
                // } else if ( dynamic_cast< const SizeofExpr * >( expr ) || dynamic_cast< const AlignofExpr * >( expr ) ) {
                //      index = 0;
                // } else {
                //      assertf( false, "2 bad designator given to ArrayIterator: %s", toString( expr ).c_str() );
                // }
        }

        void setPosition(
                std::deque<ast::ptr<ast::Expr>>::const_iterator begin,
                std::deque<ast::ptr<ast::Expr>>::const_iterator end
        ) override {
                if ( begin == end ) return;

                setPosition( *begin );
                memberIter->setPosition( ++begin, end );
        }

        std::deque< InitAlternative > operator* () const override { return first(); }

        operator bool() const override { return index < size; }
};

/// Iterates over the members of array types:
class ArrayIterator final : public IndexIterator {
        const ArrayType * array = nullptr;
        const Type * base = nullptr;

        size_t getSize( const Expr * expr ) {
                auto res = eval( expr );
                if ( !res.hasKnownValue ) {
                        SemanticError( location, "Array designator must be a constant expression %s", toString( expr ).c_str() );
                }
                return res.knownValue;
        }

public:
        ArrayIterator( const CodeLocation & loc, const ArrayType * at ) :
                        IndexIterator( loc, getSize( at->dimension) ),
                        array( at ), base( at->base ) {
                PRINT( std::cerr << "Creating array iterator: " << at << std::endl; )
                memberIter.reset( createMemberIterator( loc, base ) );
                if ( at->isVarLen ) {
                        SemanticError( location, at, "VLA initialization does not support @=: " );
                }
        }

        ArrayIterator & bigStep() override {
                PRINT( std::cerr << "bigStep in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
                ++index;
                memberIter.reset( index < size ? createMemberIterator( location, base ) : nullptr );
                return *this;
        }

        ArrayIterator & smallStep() override {
                PRINT( std::cerr << "smallStep in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
                if ( memberIter ) {
                        PRINT( std::cerr << "has member iter: " << *memberIter << std::endl; )
                        memberIter->smallStep();
                        if ( *memberIter ) {
                                PRINT( std::cerr << "has valid member iter" << std::endl; )
                                return *this;
                        }
                }
                return bigStep();
        }

        const Type * getType() override { return array; }

        const Type * getNext() override { return base; }

        std::deque< InitAlternative > first() const override {
                PRINT( std::cerr << "first in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
                if ( memberIter && *memberIter ) {
                        std::deque< InitAlternative > ret = memberIter->first();
                        for ( InitAlternative & alt : ret ) {
                                alt.designation.get_and_mutate()->designators.emplace_front( ConstantExpr::from_ulong( location, index ) );
                        }
                        return ret;
                }
                return {};
        }
};

class AggregateIterator : public MemberIterator {
protected:
        using MemberList = std::vector< ptr< Decl > >;

        CodeLocation location;
        std::string kind;  // for debug
        std::string name;
        const Type * inst;
        const MemberList & members;
        MemberList::const_iterator curMember;
        bool atbegin = true;  // false at first {small,big}Step
        const Type * curType = nullptr;
        std::unique_ptr< MemberIterator > memberIter = nullptr;
        TypeSubstitution sub;

        bool init() {
                PRINT( std::cerr << "--init()--" << members.size() << std::endl; )
                if ( curMember != members.end() ) {
                        if ( auto field = curMember->as< ObjectDecl >() ) {
                                PRINT( std::cerr << "incremented to field: " << field << std::endl; )
                                curType = field->get_type();
                                memberIter.reset( createMemberIterator( location, curType ) );
                                return true;
                        }
                }
                return false;
        }

        AggregateIterator(
                const CodeLocation & loc, const std::string k, const std::string & n, const Type * i,
                const MemberList & ms )
        : location( loc ), kind( k ), name( n ), inst( i ), members( ms ), curMember( ms.begin() ),
          sub( genericSubstitution( i ) ) {
                PRINT( std::cerr << "Creating " << kind << "(" << name << ")"; )
                init();
        }

public:
        void setPosition(
                std::deque< ptr< Expr > >::const_iterator begin,
                std::deque< ptr< Expr > >::const_iterator end
        ) final {
                if ( begin == end ) return;

                if ( auto varExpr = begin->as< VariableExpr >() ) {
                        for ( curMember = members.begin(); curMember != members.end(); ++curMember ) {
                                if ( *curMember != varExpr->var ) continue;

                                ++begin;

                                memberIter.reset( createMemberIterator( location, varExpr->result ) );
                                curType = varExpr->result;
                                atbegin = curMember == members.begin() && begin == end;
                                memberIter->setPosition( begin, end );
                                return;
                        }
                        assertf( false, "could not find member in %s: %s", kind.c_str(), toString( varExpr ).c_str() );
                } else {
                        assertf( false, "1 bad designator given to %s: %s", kind.c_str(), toString( *begin ).c_str() );
                }
        }

        std::deque< InitAlternative > operator* () const final {
                if ( memberIter && *memberIter ) {
                        std::deque< InitAlternative > ret = memberIter->first();
                        PRINT( std::cerr << "sub: " << sub << std::endl; )
                        for ( InitAlternative & alt : ret ) {
                                PRINT( std::cerr << "iterating and adding designators" << std::endl; )
                                alt.designation.get_and_mutate()->designators.emplace_front(
                                        new VariableExpr{ location, curMember->strict_as< ObjectDecl >() } );
                                // need to substitute for generic types so that casts are to concrete types
                                alt.type = shallowCopy(alt.type.get());
                                PRINT( std::cerr << "  type is: " << alt.type; )
                                sub.apply( alt.type ); // also apply to designation??
                                PRINT( std::cerr << " ==> " << alt.type << std::endl; )
                        }
                        return ret;
                }
                return {};
        }

        AggregateIterator & smallStep() final {
                PRINT( std::cerr << "smallStep in " << kind << std::endl; )
                atbegin = false;
                if ( memberIter ) {
                        PRINT( std::cerr << "has member iter, incrementing..." << std::endl; )
                        memberIter->smallStep();
                        if ( *memberIter ) {
                                PRINT( std::cerr << "success!" << std::endl; )
                                return *this;
                        }
                }
                return bigStep();
        }

        AggregateIterator & bigStep() override = 0;

        const Type * getType() final { return inst; }

        const Type * getNext() final {
                bool hasMember = memberIter && *memberIter;
                return hasMember ? memberIter->getType() : nullptr;
        }

        std::deque< InitAlternative > first() const final {
                std::deque< InitAlternative > ret;
                PRINT( std::cerr << "first " << kind << std::endl; )
                if ( memberIter && *memberIter ) {
                        PRINT( std::cerr << "adding children" << std::endl; )
                        ret = memberIter->first();
                        for ( InitAlternative & alt : ret ) {
                                PRINT( std::cerr << "iterating and adding designators" << std::endl; )
                                alt.designation.get_and_mutate()->designators.emplace_front(
                                        new VariableExpr{ location, curMember->strict_as< ObjectDecl >() } );
                        }
                }
                if ( atbegin ) {
                        // only add self if at the very beginning of the structure
                        PRINT( std::cerr << "adding self" << std::endl; )
                        ret.emplace_front( inst, new Designation{ location } );
                }
                return ret;
        }
};

class StructIterator final : public AggregateIterator {
public:
        StructIterator( const CodeLocation & loc, const StructInstType * inst )
        : AggregateIterator( loc, "StructIterator", inst->name, inst, inst->base->members ) {}

        operator bool() const override {
                return curMember != members.end() || (memberIter && *memberIter);
        }

        StructIterator & bigStep() override {
                PRINT( std::cerr << "bigStep in " << kind << std::endl; )
                atbegin = false;
                memberIter = nullptr;
                curType = nullptr;
                while ( curMember != members.end() ) {
                        ++curMember;
                        if ( init() ) return *this;
                }
                return *this;
        }
};

class UnionIterator final : public AggregateIterator {
public:
        UnionIterator( const CodeLocation & loc, const UnionInstType * inst )
        : AggregateIterator( loc, "UnionIterator", inst->name, inst, inst->base->members ) {}

        operator bool() const override { return memberIter && *memberIter; }

        UnionIterator & bigStep() override {
                // unions only initialize one member
                PRINT( std::cerr << "bigStep in " << kind << std::endl; )
                atbegin = false;
                memberIter = nullptr;
                curType = nullptr;
                curMember = members.end();
                return *this;
        }
};

/// Iterates across the positions in a tuple:
class TupleIterator final : public IndexIterator {
        ast::TupleType const * const tuple;

        const ast::Type * typeAtIndex() const {
                assert( index < size );
                return tuple->types[ index ].get();
        }

public:
        TupleIterator( const CodeLocation & loc, const TupleType * type )
        : IndexIterator( loc, type->size() ), tuple( type ) {
                PRINT( std::cerr << "Creating tuple iterator: " << type << std::endl; )
                memberIter.reset( createMemberIterator( loc, typeAtIndex() ) );
        }

        TupleIterator & bigStep() override {
                ++index;
                memberIter.reset( index < size ?
                        createMemberIterator( location, typeAtIndex() ) : nullptr );
                return *this;
        }

        TupleIterator & smallStep() override {
                if ( memberIter ) {
                        PRINT( std::cerr << "has member iter: " << *memberIter << std::endl; )
                        memberIter->smallStep();
                        if ( !memberIter ) {
                                PRINT( std::cerr << "has valid member iter" << std::endl; )
                                return *this;
                        }
                }
                return bigStep();
        }

        const ast::Type * getType() override {
                return tuple;
        }

        const ast::Type * getNext() override {
                bool hasMember = memberIter && *memberIter;
                return hasMember ? memberIter->getType() : nullptr;
        }

        std::deque< InitAlternative > first() const override {
                PRINT( std::cerr << "first in TupleIterator (" << index << "/" << size << ")" << std::endl; )
                if ( memberIter && *memberIter ) {
                        std::deque< InitAlternative > ret = memberIter->first();
                        for ( InitAlternative & alt : ret ) {
                                alt.designation.get_and_mutate()->designators.emplace_front(
                                        ConstantExpr::from_ulong( location, index ) );
                        }
                        return ret;
                }
                return {};
        }
};

MemberIterator * createMemberIterator( const CodeLocation & loc, const Type * type ) {
        if ( auto aggr = dynamic_cast< const BaseInstType * >( type ) ) {
                if ( auto sit = dynamic_cast< const StructInstType * >( aggr ) ) {
                        assert( sit->base );
                        return new StructIterator{ loc, sit };
                } else if ( auto uit = dynamic_cast< const UnionInstType * >( aggr ) ) {
                        assert( uit->base );
                        return new UnionIterator{ loc, uit };
                } else {
                        assertf(
                                dynamic_cast< const EnumInstType * >( type )
                                        || dynamic_cast< const TypeInstType * >( type ),
                                "Encountered unhandled BaseInstType in createMemberIterator: %s",
                                        toString( type ).c_str() );
                        return new SimpleIterator{ loc, type };
                }
        } else if ( auto at = dynamic_cast< const ArrayType * >( type ) ) {
                return new ArrayIterator{ loc, at };
        } else if ( auto tt = dynamic_cast< const TupleType * >( type ) ) {
                return new TupleIterator{ loc, tt };
        } else {
                return new SimpleIterator{ loc, type };
        }
}

} // namespace

CurrentObject::CurrentObject( const CodeLocation & loc, const Type * type ) : objStack() {
        objStack.emplace_back( new SimpleIterator{ loc, type } );
}

const Designation * CurrentObject::findNext( const Designation * designation ) {
        using DesignatorChain = std::deque< ptr< Expr > >;
        PRINT( std::cerr << "___findNext" << std::endl; )

        // find all the d's
        std::vector< DesignatorChain > desigAlts{ {} }, newDesigAlts;
        std::deque< const Type * > curTypes{ objStack.back()->getType() }, newTypes;
        for ( const Expr * expr : designation->designators ) {
                PRINT( std::cerr << "____untyped: " << expr << std::endl; )
                auto dit = desigAlts.begin();
                auto nexpr = dynamic_cast< const NameExpr * >( expr );

                for ( const Type * t : curTypes ) {
                        assert( dit != desigAlts.end() );
                        DesignatorChain & d = *dit;
                        // Name Designation:
                        if ( nexpr ) {
                                PRINT( std::cerr << "____actual: " << t << std::endl; )
                                if ( auto refType = dynamic_cast< const BaseInstType * >( t ) ) {
                                        // concatenate identical field names
                                        for ( const Decl * mem : refType->lookup( nexpr->name ) ) {
                                                if ( auto field = dynamic_cast< const ObjectDecl * >( mem ) ) {
                                                        PRINT( std::cerr << "____alt: " << field->type << std::endl; )
                                                        DesignatorChain d2 = d;
                                                        d2.emplace_back( new VariableExpr{ expr->location, field } );
                                                        newDesigAlts.emplace_back( std::move( d2 ) );
                                                        newTypes.emplace_back( field->type );
                                                }
                                        }
                                }

                                ++dit;
                        // Index Designation:
                        } else {
                                if ( auto at = dynamic_cast< const ArrayType * >( t ) ) {
                                        PRINT( std::cerr << "____alt: " << at->get_base() << std::endl; )
                                        d.emplace_back( expr );
                                        newDesigAlts.emplace_back( d );
                                        newTypes.emplace_back( at->base );
                                }
                        }
                }

                // reset queue
                desigAlts = std::move( newDesigAlts );
                newDesigAlts.clear();
                curTypes = std::move( newTypes );
                newTypes.clear();
                assertf( desigAlts.size() == curTypes.size(), "Designator alternatives (%zu) and current types (%zu) out of sync", desigAlts.size(), curTypes.size() );
        }

        if ( desigAlts.size() > 1 ) {
                SemanticError( designation, toString("Too many alternatives (", desigAlts.size(), ") for designation: ") );
        } else if ( desigAlts.empty() ) {
                SemanticError( designation, "No reasonable alternatives for designation: " );
        }

        DesignatorChain & d = desigAlts.back();
        PRINT( for ( Expression * expr : d ) {
                std::cerr << "____desig: " << expr << std::endl;
        } ) // for
        assertf( ! curTypes.empty(), "empty designator chosen");

        // set new designators
        assertf( ! objStack.empty(), "empty object stack when setting designation" );
        Designation * actualDesignation =
                new Designation{ designation->location, DesignatorChain{d} };
        objStack.back()->setPosition( d ); // destroys d
        return actualDesignation;
}

void CurrentObject::setNext( const Designation * designation ) {
        PRINT( std::cerr << "____setNext" << designation << std::endl; )
        assertf( ! objStack.empty(), "obj stack empty in setNext" );
        objStack.back()->setPosition( designation->designators );
}

void CurrentObject::increment() {
        PRINT( std::cerr << "____increment" << std::endl; )
        if ( objStack.empty() ) return;
        PRINT( std::cerr << *objStack.back() << std::endl; )
        objStack.back()->smallStep();
}

void CurrentObject::enterListInit( const CodeLocation & loc ) {
        PRINT( std::cerr << "____entering list init" << std::endl; )
        assertf( ! objStack.empty(), "empty obj stack entering list init" );
        const ast::Type * type = objStack.back()->getNext();
        assert( type );
        objStack.emplace_back( createMemberIterator( loc, type ) );
}

void CurrentObject::exitListInit() {
        PRINT( std::cerr << "____exiting list init" << std::endl; )
        assertf( ! objStack.empty(), "objstack empty" );
        objStack.pop_back();
        if ( ! objStack.empty() ) {
                PRINT( std::cerr << *objStack.back() << std::endl; )
                objStack.back()->bigStep();
        }
}

std::deque< InitAlternative > CurrentObject::getOptions() {
        PRINT( std::cerr << "____getting current options" << std::endl; )
        assertf( ! objStack.empty(), "objstack empty in getOptions" );
        return **objStack.back();
}

const Type * CurrentObject::getCurrentType() {
        PRINT( std::cerr << "____getting current type" << std::endl; )
        assertf( ! objStack.empty(), "objstack empty in getCurrentType" );
        return objStack.back()->getNext();
}

} // namespace ast

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