Changeset b067d9b for src/ResolvExpr/TypeEnvironment.cc

Timestamp:

Oct 29, 2019, 4:01:24 PM (6 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

773db65, 9421f3d8

Parents:

7951100 (diff), 8364209 (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' of plg.uwaterloo.ca:software/cfa/cfa-cc

File:

• src/ResolvExpr/TypeEnvironment.cc (modified) (13 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 : Andrew Beach
+// Last Modified On : Fri Jun 18 14:27:00 2019
+// Update Count     : 5
 //
 
@@ -17 +17 @@
 #include <algorithm>                   // for copy, set_intersection
 #include <iterator>                    // for ostream_iterator, insert_iterator
+#include <memory>                      // for unique_ptr
 #include <utility>                     // for pair, move
 
@@ -22 +23 @@
 #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 {
@@ -65 +69 @@
         }
 
+        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;
+        }
+
         EqvClass &EqvClass::operator=( const EqvClass &other ) {
                 if ( this == &other ) return *this;
@@ -72 +82 @@
         }
 
+        EqvClass &EqvClass::operator=( EqvClass &&other ) {
+                if ( this == &other ) return *this;
+                delete type;
+
+                vars = std::move(other.vars);
+                type = other.type;
+                other.type = nullptr;
+                allowWidening = std::move(other.allowWidening);
+                data = std::move(other.data);
+
+                return *this;
+        }
+
         EqvClass::~EqvClass() {
                 delete type;
+        }
+
+        void EqvClass::set_type( Type* ty ) {
+                if ( ty == type ) return;
+                delete type;
+                type = ty;
         }
 
@@ -91 +120 @@
 
         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 );
+                for ( ClassList::const_iterator i = env.begin(); i != env.end(); ++i ) {
+                        if ( i->vars.find( var ) != i->vars.end() ) return &*i;
                 } // for
                 return nullptr;
@@ -109 +132 @@
                         ++next;
                         std::set<std::string> intersection;
-                        std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(), 
+                        std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(),
                                 std::inserter( intersection, intersection.begin() ) );
                         if ( ! intersection.empty() ) { env.erase( i ); }
                         i = next;
                 }
-        }
-
-        void TypeEnvironment::add( const EqvClass &eqvClass ) {
-                filterOverlappingClasses( env, eqvClass );
-                env.push_back( eqvClass );
         }
 
@@ -131 +149 @@
                         newClass.vars.insert( (*i)->get_name() );
                         newClass.data = TypeDecl::Data{ (*i) };
-                        env.push_back( newClass );
+                        env.push_back( std::move(newClass) );
                 } // for
         }
@@ -145 +163 @@
                         // transition to TypeSubstitution
                         newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
-                        add( newClass );
+                        add( std::move(newClass) );
                 }
         }
 
         void TypeEnvironment::makeSubstitution( TypeSubstitution &sub ) const {
-                for ( std::list< EqvClass >::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
+                for ( ClassList::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 );
                                         delete newTypeInst;
@@ -166 +179 @@
                         } // 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();
         }
@@ -179 +188 @@
         }
 
-        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
+        TypeEnvironment::ClassList::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
+                for ( ClassList::iterator i = env.begin(); i != env.end(); ++i ) {
+                        if ( i->vars.count( var ) ) return i;
                 } // for
                 return env.end();
@@ -192 +199 @@
         }
 
-        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 ) {
-                                                        Type *newType = combineFunc( newClass.type, secondClass->type );
-                                                        delete newClass.type;
-                                                        newClass.type = newType;
-                                                        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
+        // xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
+        bool TypeEnvironment::mergeBound( EqvClass& to, const EqvClass& from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
+                if ( from.type ) {
+                        if ( to.type ) {
+                                // attempt to unify bound types
+                                std::unique_ptr<Type> toType{ to.type->clone() }, fromType{ from.type->clone() };
+                                WidenMode widen{ to.allowWidening, from.allowWidening };
+                                Type* common = nullptr;
+                                AssertionSet need, have;
+                                if ( unifyInexact( toType.get(), fromType.get(), *this, need, have, openVars, widen, indexer, common ) ) {
+                                        // unifies, set common type if necessary
+                                        if ( common ) {
+                                                common->get_qualifiers() = Type::Qualifiers{};
+                                                to.set_type( common );
+                                        }
+                                } else return false; // cannot unify
+                        } else {
+                                to.type = from.type->clone();
+                        }
+                }
+
+                // unify widening if matches
+                to.allowWidening &= from.allowWidening;
+                return true;
+        }
+
+        // xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
+        bool TypeEnvironment::mergeClasses( TypeEnvironment::ClassList::iterator to, TypeEnvironment::ClassList::iterator from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
+                EqvClass& r = *to;
+                EqvClass& s = *from;
+
+                // ensure bounds match
+                if ( ! mergeBound( r, s, openVars, indexer ) ) return false;
+
+                // check safely bindable
+                if ( r.type && occursIn( r.type, s.vars.begin(), s.vars.end(), *this ) ) return false;
+                
+                // merge classes in
+                r.vars.insert( s.vars.begin(), s.vars.end() );
+                r.allowWidening &= s.allowWidening;
+                env.erase( from );
+
+                return true;
+        }
+
+        bool TypeEnvironment::combine( const TypeEnvironment& o, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
+                // short-circuit easy cases
+                if ( o.isEmpty() ) return true;
+                if ( isEmpty() ) {
+                        simpleCombine( o );
+                        return true;
+                }
+
+                // merge classes
+                for ( auto ct = o.env.begin(); ct != o.env.end(); ++ct ) {
+                        const EqvClass& c = *ct;
+
+                        // typeclass in local environment bound to c
+                        auto rt = env.end();
+
+                        // look for first existing bound variable
+                        auto vt = c.vars.begin();
+                        for ( ; vt != c.vars.end(); ++vt ) {
+                                rt = internal_lookup( *vt );
+                                if ( rt != env.end() ) break;
+                        }
+
+                        if ( rt != env.end() ) {  // c needs to be merged into *rt
+                                EqvClass& r = *rt;
+                                // merge bindings
+                                if ( ! mergeBound( r, c, openVars, indexer ) ) return false;
+                                // merge previous unbound variables into this class, checking occurs if needed
+                                if ( r.type ) for ( auto ut = c.vars.begin(); ut != vt; ++ut ) {
+                                        if ( occurs( r.type, *ut, *this ) ) return false;
+                                        r.vars.insert( *ut );
+                                } else { r.vars.insert( c.vars.begin(), vt ); }
+                                // merge subsequent variables into this class (skipping *vt, already there)
+                                while ( ++vt != c.vars.end() ) {
+                                        auto st = internal_lookup( *vt );
+                                        if ( st == env.end() ) {
+                                                // unbound, safe to add if passes occurs
+                                                if ( r.type && occurs( r.type, *vt, *this ) ) return false;
+                                                r.vars.insert( *vt );
+                                        } else if ( st != rt ) {
+                                                // bound, but not to the same class
+                                                if ( ! mergeClasses( rt, st, openVars, indexer ) ) return false;
+                                        }   // ignore bound into the same class
+                                }
+                        } else {  // no variables in c bound; just copy up
+                                env.push_back( c );
+                        }
+                }
+
+                // merged all classes
+                return true;
         }
 
         void TypeEnvironment::extractOpenVars( OpenVarSet &openVars ) const {
-                for ( std::list< EqvClass >::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) {
+                for ( ClassList::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) {
                         for ( std::set< std::string >::const_iterator var = eqvClass->vars.begin(); var != eqvClass->vars.end(); ++var ) {
                                 openVars[ *var ] = eqvClass->data;
@@ -241 +315 @@
         }
 
+        bool isFtype( const Type * type ) {
+                if ( dynamic_cast< const FunctionType * >( type ) ) {
+                        return true;
+                } else if ( const TypeInstType *typeInst = dynamic_cast< const TypeInstType * >( type ) ) {
+                        return typeInst->get_isFtype();
+                } // if
+                return false;
+        }
+
+        bool tyVarCompatible( const TypeDecl::Data & data, const 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< const TupleType * >( type ) || Tuples::isTtype( type );
+                  default:
+                        assertf(false, "Unhandled tyvar kind: %d", data.kind);
+                } // switch
+                return false;
+        }
+
+        bool TypeEnvironment::bindVar( const TypeInstType *typeInst, Type *bindTo, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widen, 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
+                                std::unique_ptr< Type > newType( curClass->type->clone() );
+                                newType->tq = typeInst->tq;
+                                if ( unifyInexact( newType.get(), bindTo, *this, need, have, openVars, widen & 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 = widen.first && widen.second;
+                        } // if
+                } else {
+                        EqvClass newClass;
+                        newClass.vars.insert( typeInst->get_name() );
+                        newClass.type = bindTo->clone();
+                        newClass.type->get_qualifiers() = Type::Qualifiers();
+                        newClass.allowWidening = widen.first && widen.second;
+                        newClass.data = data;
+                        env.push_back( std::move(newClass) );
+                } // if
+                return true;
+        }
+
+        bool TypeEnvironment::bindVarToVar( const TypeInstType * var1, const TypeInstType * var2,
+                        TypeDecl::Data && data, AssertionSet &need, AssertionSet &have,
+                        const OpenVarSet &openVars, WidenMode widen, 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 &= widen;
+                        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 = widen.first && 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 = widen.second && class2->allowWidening;
+                } // if
+
+                if ( type1 && type2 ) {
+                        // both classes bound, merge if bound types can be unified
+                        std::unique_ptr<Type> newType1{ type1->clone() }, newType2{ type2->clone() };
+                        WidenMode newWidenMode{ widen1, widen2 };
+                        Type *common = 0;
+                        if ( unifyInexact( newType1.get(), newType2.get(), *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 );
+                                }
+                                class1->data.isComplete |= data.isComplete;
+                                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;
+                                class1->data.isComplete |= data.isComplete;
+                                env.erase( class2 );
+                        } else {
+                                class2->vars.insert( class1->vars.begin(), class1->vars.end() );
+                                class2->allowWidening = widen2;
+                                class2->data.isComplete |= data.isComplete;
+                                env.erase( class1 );
+                        } // if
+                } else if ( class1 != env.end() ) {
+                        // var2 unbound, add to class1
+                        class1->vars.insert( var2->get_name() );
+                        class1->allowWidening = widen1;
+                        class1->data.isComplete |= data.isComplete;
+                } else if ( class2 != env.end() ) {
+                        // var1 unbound, add to class2
+                        class2->vars.insert( var1->get_name() );
+                        class2->allowWidening = widen2;
+                        class2->data.isComplete |= data.isComplete;
+                } 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 );