Changeset 28f3a19 for src/ResolvExpr/TypeEnvironment.cc

Timestamp:

Jun 27, 2018, 3:28:41 PM (6 years ago)

Author:

Aaron Moss <a3moss@…>

Branches:

new-env, with_gc

Children:

b21c77a

Parents:

0182bfa (diff), 63238a4 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'master' into with_gc

File:

• src/ResolvExpr/TypeEnvironment.cc (modified) (12 diffs)

src/ResolvExpr/TypeEnvironment.cc

@@ -9 +9 @@
 // Author           : Richard C. Bilson
 // Created On       : Sun May 17 12:19:47 2015
-// Last Modified By : Peter A. Buhr
-// Last Modified On : Sun May 17 12:23:36 2015
-// Update Count     : 3
+// Last Modified By : Aaron B. Moss
+// Last Modified On : Mon Jun 18 11:58:00 2018
+// Update Count     : 4
 //
 
@@ -24 +24 @@
 #include "SynTree/Type.h"              // for Type, FunctionType, Type::Fora...
 #include "SynTree/TypeSubstitution.h"  // for TypeSubstitution
+#include "Tuples/Tuples.h"             // for isTtype
 #include "TypeEnvironment.h"
+#include "typeops.h"                   // for occurs
+#include "Unify.h"                     // for unifyInexact
 
 namespace ResolvExpr {
@@ -46 +49 @@
 
         void EqvClass::initialize( const EqvClass &src, EqvClass &dest ) {
+                initialize( src, dest, src.type );
+        }
+
+        void EqvClass::initialize( const EqvClass &src, EqvClass &dest, const Type *ty ) {
                 dest.vars = src.vars;
-                dest.type = maybeClone( src.type );
+                dest.type = maybeClone( ty );
                 dest.allowWidening = src.allowWidening;
                 dest.data = src.data;
         }
 
-        EqvClass::EqvClass() : type( 0 ), allowWidening( true ) {
+        EqvClass::EqvClass() : type( nullptr ), allowWidening( true ) {
         }
 
         EqvClass::EqvClass( const EqvClass &other ) {
                 initialize( other, *this );
+        }
+
+        EqvClass::EqvClass( const EqvClass &other, const Type *ty ) {
+                initialize( other, *this, ty );
+        }
+
+        EqvClass::EqvClass( EqvClass &&other ) 
+        : vars{std::move(other.vars)}, type{other.type}, 
+          allowWidening{std::move(other.allowWidening)}, data{std::move(other.data)} {
+                  other.type = nullptr;
         }
 
@@ -64 +81 @@
                 return *this;
         }
+
+        EqvClass &EqvClass::operator=( EqvClass &&other ) {
+                if ( this == &other ) return *this;
+                
+                vars = std::move(other.vars);
+                type = other.type;
+                allowWidening = std::move(other.allowWidening);
+                data = std::move(other.data);
+
+                return *this;
+        }
+
+        void EqvClass::set_type( Type* ty ) { type = ty; }
 
         void EqvClass::print( std::ostream &os, Indenter indent ) const {
@@ -81 +111 @@
         const EqvClass* TypeEnvironment::lookup( const std::string &var ) const {
                 for ( std::list< EqvClass >::const_iterator i = env.begin(); i != env.end(); ++i ) {
-                        if ( i->vars.find( var ) != i->vars.end() ) {
-///       std::cout << var << " is in class ";
-///       i->print( std::cout );
-                                return &*i;
-                        }
-///     std::cout << var << " is not in class ";
-///     i->print( std::cout );
+                        if ( i->vars.find( var ) != i->vars.end() ) return &*i;
                 } // for
                 return nullptr;
@@ -105 +129 @@
         }
 
-        void TypeEnvironment::add( const EqvClass &eqvClass ) {
-                filterOverlappingClasses( env, eqvClass );
-                env.push_back( eqvClass );
-        }
-
         void TypeEnvironment::add( EqvClass &&eqvClass ) {
                 filterOverlappingClasses( env, eqvClass );
@@ -120 +139 @@
                         newClass.vars.insert( (*i)->get_name() );
                         newClass.data = TypeDecl::Data{ (*i) };
-                        env.push_back( newClass );
+                        env.push_back( std::move(newClass) );
                 } // for
         }
@@ -134 +153 @@
                         // transition to TypeSubstitution
                         newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
-                        add( newClass );
+                        add( std::move(newClass) );
                 }
         }
@@ -141 +160 @@
                 for ( std::list< EqvClass >::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
                         for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) {
-///       std::cerr << "adding " << *theVar;
                                 if ( theClass->type ) {
-///         std::cerr << " bound to ";
-///         theClass->type->print( std::cerr );
-///         std::cerr << std::endl;
                                         sub.add( *theVar, theClass->type );
                                 } else if ( theVar != theClass->vars.begin() ) {
                                         TypeInstType *newTypeInst = new TypeInstType( Type::Qualifiers(), *theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype );
-///         std::cerr << " bound to variable " << *theClass->vars.begin() << std::endl;
                                         sub.add( *theVar, newTypeInst );
                                 } // if
                         } // for
                 } // for
-///   std::cerr << "input env is:" << std::endl;
-///   print( std::cerr, 8 );
-///   std::cerr << "sub is:" << std::endl;
-///   sub.print( std::cerr, 8 );
                 sub.normalize();
         }
 
         void TypeEnvironment::print( std::ostream &os, Indenter indent ) const {
-                for ( std::list< EqvClass >::const_iterator i = env.begin(); i != env.end(); ++i ) {
-                        i->print( os, indent );
+                for ( const EqvClass & theClass : env ) {
+                        theClass.print( os, indent );
                 } // for
         }
@@ -169 +179 @@
         std::list< EqvClass >::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
                 for ( std::list< EqvClass >::iterator i = env.begin(); i != env.end(); ++i ) {
-                        if ( i->vars.find( var ) == i->vars.end() ) {
-                                return i;
-                        } // if
+                        if ( i->vars.count( var ) ) return i;
                 } // for
                 return env.end();
@@ -178 +186 @@
         void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) {
                 env.insert( env.end(), second.env.begin(), second.env.end() );
-        }
-
-        void TypeEnvironment::combine( const TypeEnvironment &second, Type *(*combineFunc)( Type*, Type* ) ) {
-                TypeEnvironment secondCopy( second );
-                for ( std::list< EqvClass >::iterator firstClass = env.begin(); firstClass != env.end(); ++firstClass ) {
-                        EqvClass &newClass = *firstClass;
-                        std::set< std::string > newVars;
-                        for ( std::set< std::string >::const_iterator var = firstClass->vars.begin(); var != firstClass->vars.end(); ++var ) {
-                                std::list< EqvClass >::iterator secondClass = secondCopy.internal_lookup( *var );
-                                if ( secondClass != secondCopy.env.end() ) {
-                                        newVars.insert( secondClass->vars.begin(), secondClass->vars.end() );
-                                        if ( secondClass->type ) {
-                                                if ( newClass.type ) {
-                                                        newClass.type = combineFunc( newClass.type, secondClass->type );
-                                                        newClass.allowWidening = newClass.allowWidening && secondClass->allowWidening;
-                                                } else {
-                                                        newClass.type = secondClass->type->clone();
-                                                        newClass.allowWidening = secondClass->allowWidening;
-                                                } // if
-                                        } // if
-                                        secondCopy.env.erase( secondClass );
-                                } // if
-                        } // for
-                        newClass.vars.insert( newVars.begin(), newVars.end() );
-                } // for
-                for ( std::list< EqvClass >::iterator secondClass = secondCopy.env.begin(); secondClass != secondCopy.env.end(); ++secondClass ) {
-                        env.push_back( *secondClass );
-                } // for
         }
 
@@ -227 +207 @@
         }
 
+        bool isFtype( Type *type ) {
+                if ( dynamic_cast< FunctionType* >( type ) ) {
+                        return true;
+                } else if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( type ) ) {
+                        return typeInst->get_isFtype();
+                } // if
+                return false;
+        }
+
+        bool tyVarCompatible( const TypeDecl::Data & data, Type *type ) {
+                switch ( data.kind ) {
+                  case TypeDecl::Dtype:
+                        // to bind to an object type variable, the type must not be a function type.
+                        // if the type variable is specified to be a complete type then the incoming
+                        // type must also be complete
+                        // xxx - should this also check that type is not a tuple type and that it's not a ttype?
+                        return ! isFtype( type ) && (! data.isComplete || type->isComplete() );
+                  case TypeDecl::Ftype:
+                        return isFtype( type );
+                  case TypeDecl::Ttype:
+                        // ttype unifies with any tuple type
+                        return dynamic_cast< TupleType * >( type ) || Tuples::isTtype( type );
+                } // switch
+                return false;
+        }
+
+        bool TypeEnvironment::bindVar( TypeInstType *typeInst, Type *bindTo, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
+                
+                // remove references from other, so that type variables can only bind to value types
+                bindTo = bindTo->stripReferences();
+                OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
+                assert( tyvar != openVars.end() );
+                if ( ! tyVarCompatible( tyvar->second, bindTo ) ) {
+                        return false;
+                } // if
+                if ( occurs( bindTo, typeInst->get_name(), *this ) ) {
+                        return false;
+                } // if
+                auto curClass = internal_lookup( typeInst->get_name() );
+                if ( curClass != env.end() ) {
+                        if ( curClass->type ) {
+                                Type *common = 0;
+                                // attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
+                                Type *newType = curClass->type->clone();
+                                newType->get_qualifiers() = typeInst->get_qualifiers();
+                                if ( unifyInexact( newType, bindTo, *this, need, have, openVars, widenMode & WidenMode( curClass->allowWidening, true ), indexer, common ) ) {
+                                        if ( common ) {
+                                                common->get_qualifiers() = Type::Qualifiers{};
+                                                curClass->set_type( common );
+                                        } // if
+                                } else return false;
+                        } else {
+                                Type* newType = bindTo->clone();
+                                newType->get_qualifiers() = Type::Qualifiers{};
+                                curClass->set_type( newType );
+                                curClass->allowWidening = widenMode.widenFirst && widenMode.widenSecond;
+                        } // if
+                } else {
+                        EqvClass newClass;
+                        newClass.vars.insert( typeInst->get_name() );
+                        newClass.type = bindTo->clone();
+                        newClass.type->get_qualifiers() = Type::Qualifiers();
+                        newClass.allowWidening = widenMode.widenFirst && widenMode.widenSecond;
+                        newClass.data = data;
+                        env.push_back( std::move(newClass) );
+                } // if
+                return true;
+        }
+
+        bool TypeEnvironment::bindVarToVar( TypeInstType *var1, TypeInstType *var2, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
+
+                auto class1 = internal_lookup( var1->get_name() );
+                auto class2 = internal_lookup( var2->get_name() );
+                
+                // exit early if variables already bound together
+                if ( class1 != env.end() && class1 == class2 ) {
+                        class1->allowWidening &= widenMode;
+                        return true;
+                }
+
+                bool widen1 = false, widen2 = false;
+                const Type *type1 = nullptr, *type2 = nullptr;
+
+                // check for existing bindings, perform occurs check
+                if ( class1 != env.end() ) {
+                        if ( class1->type ) {
+                                if ( occurs( class1->type, var2->get_name(), *this ) ) return false;
+                                type1 = class1->type;
+                        } // if
+                        widen1 = widenMode.widenFirst && class1->allowWidening;
+                } // if
+                if ( class2 != env.end() ) {
+                        if ( class2->type ) {
+                                if ( occurs( class2->type, var1->get_name(), *this ) ) return false;
+                                type2 = class2->type;
+                        } // if
+                        widen2 = widenMode.widenSecond && class2->allowWidening;
+                } // if
+
+                if ( type1 && type2 ) {
+                        // both classes bound, merge if bound types can be unified
+                        Type *newType1 = type1->clone(), *newType2 = type2->clone();
+                        WidenMode newWidenMode{ widen1, widen2 };
+                        Type *common = 0;
+                        if ( unifyInexact( newType1, newType2, *this, need, have, openVars, newWidenMode, indexer, common ) ) {
+                                class1->vars.insert( class2->vars.begin(), class2->vars.end() );
+                                class1->allowWidening = widen1 && widen2;
+                                if ( common ) {
+                                        common->get_qualifiers() = Type::Qualifiers{};
+                                        class1->set_type( common );
+                                }
+                                env.erase( class2 );
+                        } else return false;
+                } else if ( class1 != env.end() && class2 != env.end() ) {
+                        // both classes exist, at least one unbound, merge unconditionally
+                        if ( type1 ) {
+                                class1->vars.insert( class2->vars.begin(), class2->vars.end() );
+                                class1->allowWidening = widen1;
+                                env.erase( class2 );
+                        } else {
+                                class2->vars.insert( class1->vars.begin(), class1->vars.end() );
+                                class2->allowWidening = widen2;
+                                env.erase( class1 );
+                        } // if
+                } else if ( class1 != env.end() ) {
+                        // var2 unbound, add to class1
+                        class1->vars.insert( var2->get_name() );
+                        class1->allowWidening = widen1;
+                } else if ( class2 != env.end() ) {
+                        // var1 unbound, add to class2
+                        class2->vars.insert( var1->get_name() );
+                        class2->allowWidening = widen2;
+                } else {
+                        // neither var bound, create new class
+                        EqvClass newClass;
+                        newClass.vars.insert( var1->get_name() );
+                        newClass.vars.insert( var2->get_name() );
+                        newClass.allowWidening = widen1 && widen2;
+                        newClass.data = data;
+                        env.push_back( std::move(newClass) );
+                } // if
+                return true;
+        }
+
+        void TypeEnvironment::forbidWidening() {
+                for ( EqvClass& c : env ) c.allowWidening = false;
+        }
+
         std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) {
                 env.print( out );