| 1 | //
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
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| 3 | //
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| 4 | // The contents of this file are covered under the licence agreement in the
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| 5 | // file "LICENCE" distributed with Cforall.
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| 6 | //
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| 7 | // TypeEnvironment.cc --
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| 8 | //
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| 9 | // Author : Richard C. Bilson
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| 10 | // Created On : Sun May 17 12:19:47 2015
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| 11 | // Last Modified By : Aaron B. Moss
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| 12 | // Last Modified On : Mon Jun 18 11:58:00 2018
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| 13 | // Update Count : 4
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| 14 | //
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| 15 |
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| 16 | #include <cassert> // for assert
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| 17 | #include <algorithm> // for copy, set_intersection
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| 18 | #include <iterator> // for ostream_iterator, insert_iterator
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| 19 | #include <memory> // for unique_ptr
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| 20 | #include <utility> // for pair, move
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| 21 |
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| 22 | #include "Common/utility.h" // for maybeClone
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| 23 | #include "SynTree/Type.h" // for Type, FunctionType, Type::Fora...
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| 24 | #include "SynTree/TypeSubstitution.h" // for TypeSubstitution
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| 25 | #include "Tuples/Tuples.h" // for isTtype
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| 26 | #include "TypeEnvironment.h"
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| 27 | #include "typeops.h" // for occurs
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| 28 | #include "Unify.h" // for unifyInexact
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| 29 |
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| 30 | namespace ResolvExpr {
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| 31 | void printAssertionSet( const AssertionSet &assertions, std::ostream &os, int indent ) {
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| 32 | for ( AssertionSet::const_iterator i = assertions.begin(); i != assertions.end(); ++i ) {
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| 33 | i->first->print( os, indent );
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| 34 | if ( i->second.isUsed ) {
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| 35 | os << "(used)";
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| 36 | } else {
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| 37 | os << "(not used)";
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| 38 | } // if
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| 39 | } // for
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| 40 | }
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| 41 |
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| 42 | void printOpenVarSet( const OpenVarSet &openVars, std::ostream &os, int indent ) {
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| 43 | os << std::string( indent, ' ' );
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| 44 | for ( OpenVarSet::const_iterator i = openVars.begin(); i != openVars.end(); ++i ) {
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| 45 | os << i->first << "(" << i->second << ") ";
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| 46 | } // for
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| 47 | }
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| 48 |
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| 49 | void EqvClass::initialize( const EqvClass &src, EqvClass &dest ) {
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| 50 | initialize( src, dest, src.type );
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| 51 | }
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| 52 |
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| 53 | void EqvClass::initialize( const EqvClass &src, EqvClass &dest, const Type *ty ) {
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| 54 | dest.vars = src.vars;
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| 55 | dest.type = maybeClone( ty );
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| 56 | dest.allowWidening = src.allowWidening;
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| 57 | dest.data = src.data;
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| 58 | }
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| 59 |
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| 60 | EqvClass::EqvClass() : type( nullptr ), allowWidening( true ) {
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| 61 | }
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| 62 |
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| 63 | EqvClass::EqvClass( const EqvClass &other ) {
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| 64 | initialize( other, *this );
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| 65 | }
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| 66 |
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| 67 | EqvClass::EqvClass( const EqvClass &other, const Type *ty ) {
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| 68 | initialize( other, *this, ty );
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| 69 | }
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| 70 |
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| 71 | EqvClass::EqvClass( EqvClass &&other )
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| 72 | : vars{std::move(other.vars)}, type{other.type},
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| 73 | allowWidening{std::move(other.allowWidening)}, data{std::move(other.data)} {
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| 74 | other.type = nullptr;
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| 75 | }
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| 76 |
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| 77 | EqvClass &EqvClass::operator=( const EqvClass &other ) {
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| 78 | if ( this == &other ) return *this;
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| 79 | delete type;
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| 80 | initialize( other, *this );
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| 81 | return *this;
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| 82 | }
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| 83 |
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| 84 | EqvClass &EqvClass::operator=( EqvClass &&other ) {
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| 85 | if ( this == &other ) return *this;
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| 86 | delete type;
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| 87 |
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| 88 | vars = std::move(other.vars);
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| 89 | type = other.type;
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| 90 | other.type = nullptr;
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| 91 | allowWidening = std::move(other.allowWidening);
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| 92 | data = std::move(other.data);
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| 93 |
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| 94 | return *this;
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| 95 | }
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| 96 |
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| 97 | EqvClass::~EqvClass() {
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| 98 | delete type;
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| 99 | }
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| 100 |
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| 101 | void EqvClass::set_type( Type* ty ) {
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| 102 | if ( ty == type ) return;
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| 103 | delete type;
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| 104 | type = ty;
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| 105 | }
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| 106 |
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| 107 | void EqvClass::print( std::ostream &os, Indenter indent ) const {
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| 108 | os << "( ";
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| 109 | std::copy( vars.begin(), vars.end(), std::ostream_iterator< std::string >( os, " " ) );
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| 110 | os << ")";
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| 111 | if ( type ) {
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| 112 | os << " -> ";
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| 113 | type->print( os, indent+1 );
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| 114 | } // if
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| 115 | if ( ! allowWidening ) {
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| 116 | os << " (no widening)";
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| 117 | } // if
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| 118 | os << std::endl;
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| 119 | }
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| 120 |
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| 121 | const EqvClass* TypeEnvironment::lookup( const std::string &var ) const {
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| 122 | for ( std::list< EqvClass >::const_iterator i = env.begin(); i != env.end(); ++i ) {
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| 123 | if ( i->vars.find( var ) != i->vars.end() ) return &*i;
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| 124 | } // for
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| 125 | return nullptr;
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| 126 | }
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| 127 |
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| 128 | /// Removes any class from env that intersects eqvClass
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| 129 | void filterOverlappingClasses( std::list<EqvClass> &env, const EqvClass &eqvClass ) {
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| 130 | for ( auto i = env.begin(); i != env.end(); ) {
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| 131 | auto next = i;
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| 132 | ++next;
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| 133 | std::set<std::string> intersection;
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| 134 | std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(),
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| 135 | std::inserter( intersection, intersection.begin() ) );
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| 136 | if ( ! intersection.empty() ) { env.erase( i ); }
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| 137 | i = next;
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| 138 | }
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| 139 | }
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| 140 |
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| 141 | void TypeEnvironment::add( EqvClass &&eqvClass ) {
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| 142 | filterOverlappingClasses( env, eqvClass );
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| 143 | env.push_back( std::move(eqvClass) );
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| 144 | }
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| 145 |
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| 146 | void TypeEnvironment::add( const Type::ForallList &tyDecls ) {
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| 147 | for ( Type::ForallList::const_iterator i = tyDecls.begin(); i != tyDecls.end(); ++i ) {
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| 148 | EqvClass newClass;
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| 149 | newClass.vars.insert( (*i)->get_name() );
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| 150 | newClass.data = TypeDecl::Data{ (*i) };
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| 151 | env.push_back( std::move(newClass) );
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| 152 | } // for
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| 153 | }
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| 154 |
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| 155 | void TypeEnvironment::add( const TypeSubstitution & sub ) {
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| 156 | EqvClass newClass;
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| 157 | for ( auto p : sub ) {
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| 158 | newClass.vars.insert( p.first );
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| 159 | newClass.type = p.second->clone();
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| 160 | newClass.allowWidening = false;
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| 161 | // Minimal assumptions. Not technically correct, but might be good enough, and
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| 162 | // is the best we can do at the moment since information is lost in the
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| 163 | // transition to TypeSubstitution
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| 164 | newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
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| 165 | add( std::move(newClass) );
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| 166 | }
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| 167 | }
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| 168 |
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| 169 | void TypeEnvironment::makeSubstitution( TypeSubstitution &sub ) const {
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| 170 | for ( std::list< EqvClass >::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
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| 171 | for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) {
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| 172 | if ( theClass->type ) {
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| 173 | sub.add( *theVar, theClass->type );
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| 174 | } else if ( theVar != theClass->vars.begin() ) {
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| 175 | TypeInstType *newTypeInst = new TypeInstType( Type::Qualifiers(), *theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype );
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| 176 | sub.add( *theVar, newTypeInst );
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| 177 | delete newTypeInst;
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| 178 | } // if
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| 179 | } // for
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| 180 | } // for
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| 181 | sub.normalize();
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| 182 | }
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| 183 |
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| 184 | void TypeEnvironment::print( std::ostream &os, Indenter indent ) const {
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| 185 | for ( const EqvClass & theClass : env ) {
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| 186 | theClass.print( os, indent );
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| 187 | } // for
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| 188 | }
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| 189 |
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| 190 | std::list< EqvClass >::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
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| 191 | for ( std::list< EqvClass >::iterator i = env.begin(); i != env.end(); ++i ) {
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| 192 | if ( i->vars.count( var ) ) return i;
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| 193 | } // for
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| 194 | return env.end();
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| 195 | }
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| 196 |
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| 197 | void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) {
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| 198 | env.insert( env.end(), second.env.begin(), second.env.end() );
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| 199 | }
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| 200 |
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| 201 | void TypeEnvironment::extractOpenVars( OpenVarSet &openVars ) const {
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| 202 | for ( std::list< EqvClass >::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) {
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| 203 | for ( std::set< std::string >::const_iterator var = eqvClass->vars.begin(); var != eqvClass->vars.end(); ++var ) {
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| 204 | openVars[ *var ] = eqvClass->data;
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| 205 | } // for
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| 206 | } // for
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| 207 | }
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| 208 |
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| 209 | void TypeEnvironment::addActual( const TypeEnvironment& actualEnv, OpenVarSet& openVars ) {
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| 210 | for ( const EqvClass& c : actualEnv ) {
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| 211 | EqvClass c2 = c;
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| 212 | c2.allowWidening = false;
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| 213 | for ( const std::string& var : c2.vars ) {
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| 214 | openVars[ var ] = c2.data;
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| 215 | }
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| 216 | env.push_back( std::move(c2) );
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| 217 | }
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| 218 | }
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| 219 |
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| 220 | bool isFtype( Type *type ) {
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| 221 | if ( dynamic_cast< FunctionType* >( type ) ) {
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| 222 | return true;
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| 223 | } else if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( type ) ) {
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| 224 | return typeInst->get_isFtype();
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| 225 | } // if
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| 226 | return false;
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| 227 | }
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| 228 |
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| 229 | bool tyVarCompatible( const TypeDecl::Data & data, Type *type ) {
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| 230 | switch ( data.kind ) {
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| 231 | case TypeDecl::Dtype:
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| 232 | // to bind to an object type variable, the type must not be a function type.
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| 233 | // if the type variable is specified to be a complete type then the incoming
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| 234 | // type must also be complete
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| 235 | // xxx - should this also check that type is not a tuple type and that it's not a ttype?
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| 236 | return ! isFtype( type ) && (! data.isComplete || type->isComplete() );
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| 237 | case TypeDecl::Ftype:
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| 238 | return isFtype( type );
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| 239 | case TypeDecl::Ttype:
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| 240 | // ttype unifies with any tuple type
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| 241 | return dynamic_cast< TupleType * >( type ) || Tuples::isTtype( type );
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| 242 | default:
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| 243 | assertf(false, "Unhandled tyvar kind: %d", data.kind);
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| 244 | } // switch
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| 245 | return false;
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| 246 | }
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| 247 |
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| 248 | bool TypeEnvironment::bindVar( TypeInstType *typeInst, Type *bindTo, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
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| 249 |
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| 250 | // remove references from other, so that type variables can only bind to value types
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| 251 | bindTo = bindTo->stripReferences();
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| 252 | OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
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| 253 | assert( tyvar != openVars.end() );
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| 254 | if ( ! tyVarCompatible( tyvar->second, bindTo ) ) {
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| 255 | return false;
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| 256 | } // if
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| 257 | if ( occurs( bindTo, typeInst->get_name(), *this ) ) {
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| 258 | return false;
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| 259 | } // if
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| 260 | auto curClass = internal_lookup( typeInst->get_name() );
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| 261 | if ( curClass != env.end() ) {
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| 262 | if ( curClass->type ) {
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| 263 | Type *common = 0;
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| 264 | // attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
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| 265 | std::unique_ptr< Type > newType( curClass->type->clone() );
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| 266 | newType->get_qualifiers() = typeInst->get_qualifiers();
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| 267 | if ( unifyInexact( newType.get(), bindTo, *this, need, have, openVars, widenMode & WidenMode( curClass->allowWidening, true ), indexer, common ) ) {
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| 268 | if ( common ) {
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| 269 | common->get_qualifiers() = Type::Qualifiers{};
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| 270 | curClass->set_type( common );
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| 271 | } // if
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| 272 | } else return false;
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| 273 | } else {
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| 274 | Type* newType = bindTo->clone();
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| 275 | newType->get_qualifiers() = Type::Qualifiers{};
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| 276 | curClass->set_type( newType );
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| 277 | curClass->allowWidening = widenMode.widenFirst && widenMode.widenSecond;
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| 278 | } // if
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| 279 | } else {
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| 280 | EqvClass newClass;
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| 281 | newClass.vars.insert( typeInst->get_name() );
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| 282 | newClass.type = bindTo->clone();
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| 283 | newClass.type->get_qualifiers() = Type::Qualifiers();
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| 284 | newClass.allowWidening = widenMode.widenFirst && widenMode.widenSecond;
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| 285 | newClass.data = data;
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| 286 | env.push_back( std::move(newClass) );
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| 287 | } // if
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| 288 | return true;
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| 289 | }
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| 290 |
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| 291 | bool TypeEnvironment::bindVarToVar( TypeInstType *var1, TypeInstType *var2, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
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| 292 |
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| 293 | auto class1 = internal_lookup( var1->get_name() );
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| 294 | auto class2 = internal_lookup( var2->get_name() );
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| 295 |
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| 296 | // exit early if variables already bound together
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| 297 | if ( class1 != env.end() && class1 == class2 ) {
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| 298 | class1->allowWidening &= widenMode;
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| 299 | return true;
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| 300 | }
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| 301 |
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| 302 | bool widen1 = false, widen2 = false;
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| 303 | const Type *type1 = nullptr, *type2 = nullptr;
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| 304 |
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| 305 | // check for existing bindings, perform occurs check
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| 306 | if ( class1 != env.end() ) {
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| 307 | if ( class1->type ) {
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| 308 | if ( occurs( class1->type, var2->get_name(), *this ) ) return false;
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| 309 | type1 = class1->type;
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| 310 | } // if
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| 311 | widen1 = widenMode.widenFirst && class1->allowWidening;
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| 312 | } // if
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| 313 | if ( class2 != env.end() ) {
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| 314 | if ( class2->type ) {
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| 315 | if ( occurs( class2->type, var1->get_name(), *this ) ) return false;
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| 316 | type2 = class2->type;
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| 317 | } // if
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| 318 | widen2 = widenMode.widenSecond && class2->allowWidening;
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| 319 | } // if
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| 320 |
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| 321 | if ( type1 && type2 ) {
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| 322 | // both classes bound, merge if bound types can be unified
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| 323 | std::unique_ptr<Type> newType1{ type1->clone() }, newType2{ type2->clone() };
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| 324 | WidenMode newWidenMode{ widen1, widen2 };
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| 325 | Type *common = 0;
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| 326 | if ( unifyInexact( newType1.get(), newType2.get(), *this, need, have, openVars, newWidenMode, indexer, common ) ) {
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| 327 | class1->vars.insert( class2->vars.begin(), class2->vars.end() );
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| 328 | class1->allowWidening = widen1 && widen2;
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| 329 | if ( common ) {
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| 330 | common->get_qualifiers() = Type::Qualifiers{};
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| 331 | class1->set_type( common );
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| 332 | }
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| 333 | env.erase( class2 );
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| 334 | } else return false;
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| 335 | } else if ( class1 != env.end() && class2 != env.end() ) {
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| 336 | // both classes exist, at least one unbound, merge unconditionally
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| 337 | if ( type1 ) {
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| 338 | class1->vars.insert( class2->vars.begin(), class2->vars.end() );
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| 339 | class1->allowWidening = widen1;
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| 340 | env.erase( class2 );
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| 341 | } else {
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| 342 | class2->vars.insert( class1->vars.begin(), class1->vars.end() );
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| 343 | class2->allowWidening = widen2;
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| 344 | env.erase( class1 );
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| 345 | } // if
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| 346 | } else if ( class1 != env.end() ) {
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| 347 | // var2 unbound, add to class1
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| 348 | class1->vars.insert( var2->get_name() );
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| 349 | class1->allowWidening = widen1;
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| 350 | } else if ( class2 != env.end() ) {
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| 351 | // var1 unbound, add to class2
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| 352 | class2->vars.insert( var1->get_name() );
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| 353 | class2->allowWidening = widen2;
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| 354 | } else {
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| 355 | // neither var bound, create new class
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| 356 | EqvClass newClass;
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| 357 | newClass.vars.insert( var1->get_name() );
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| 358 | newClass.vars.insert( var2->get_name() );
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| 359 | newClass.allowWidening = widen1 && widen2;
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| 360 | newClass.data = data;
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| 361 | env.push_back( std::move(newClass) );
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| 362 | } // if
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| 363 | return true;
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| 364 | }
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| 365 |
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| 366 | void TypeEnvironment::forbidWidening() {
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| 367 | for ( EqvClass& c : env ) c.allowWidening = false;
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| 368 | }
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| 369 |
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| 370 | std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) {
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| 371 | env.print( out );
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| 372 | return out;
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| 373 | }
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| 374 | } // namespace ResolvExpr
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| 375 |
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| 376 | // Local Variables: //
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| 377 | // tab-width: 4 //
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| 378 | // mode: c++ //
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| 379 | // compile-command: "make install" //
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| 380 | // End: //
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