Changes in src/ResolvExpr/Resolver.cc [c6b4432:4894239]

File:

• src/ResolvExpr/Resolver.cc (modified) (4 diffs)

src/ResolvExpr/Resolver.cc

@@ -19 +19 @@
 #include <vector>                        // for vector
 
+#include "Alternative.h"                 // for Alternative, AltList
+#include "AlternativeFinder.h"           // for AlternativeFinder, resolveIn...
 #include "Candidate.hpp"
 #include "CandidateFinder.hpp"
@@ -38 +40 @@
 #include "Common/Eval.h"                 // for eval
 #include "Common/Iterate.hpp"            // for group_iterate
+#include "Common/PassVisitor.h"          // for PassVisitor
 #include "Common/SemanticError.h"        // for SemanticError
 #include "Common/Stats/ResolveTime.h"    // for ResolveTime::start(), ResolveTime::stop()
 #include "Common/ToString.hpp"           // for toCString
-#include "Common/UniqueName.h"           // for UniqueName
 #include "InitTweak/GenInit.h"
 #include "InitTweak/InitTweak.h"         // for isIntrinsicSingleArgCallStmt
+#include "ResolvExpr/TypeEnvironment.h"  // for TypeEnvironment
+#include "SymTab/Autogen.h"              // for SizeType
+#include "SymTab/Indexer.h"              // for Indexer
 #include "SymTab/Mangler.h"              // for Mangler
+#include "SynTree/Declaration.h"         // for ObjectDecl, TypeDecl, Declar...
+#include "SynTree/Expression.h"          // for Expression, CastExpr, InitExpr
+#include "SynTree/Initializer.h"         // for ConstructorInit, SingleInit
+#include "SynTree/Statement.h"           // for ForStmt, Statement, BranchStmt
+#include "SynTree/Type.h"                // for Type, BasicType, PointerType
+#include "SynTree/TypeSubstitution.h"    // for TypeSubstitution
+#include "SynTree/Visitor.h"             // for acceptAll, maybeAccept
 #include "Tuples/Tuples.h"
 #include "Validate/FindSpecialDecls.h"   // for SizeType
@@ -51 +63 @@
 
 namespace ResolvExpr {
+        struct Resolver_old final : public WithIndexer, public WithGuards, public WithVisitorRef<Resolver_old>, public WithShortCircuiting, public WithStmtsToAdd {
+                Resolver_old() {}
+                Resolver_old( const SymTab::Indexer & other ) {
+                        indexer = other;
+                }
+
+                void previsit( FunctionDecl * functionDecl );
+                void postvisit( FunctionDecl * functionDecl );
+                void previsit( ObjectDecl * objectDecll );
+                void previsit( EnumDecl * enumDecl );
+                void previsit( StaticAssertDecl * assertDecl );
+
+                void previsit( ArrayType * at );
+                void previsit( PointerType * at );
+
+                void previsit( ExprStmt * exprStmt );
+                void previsit( AsmExpr * asmExpr );
+                void previsit( AsmStmt * asmStmt );
+                void previsit( IfStmt * ifStmt );
+                void previsit( WhileDoStmt * whileDoStmt );
+                void previsit( ForStmt * forStmt );
+                void previsit( SwitchStmt * switchStmt );
+                void previsit( CaseStmt * caseStmt );
+                void previsit( BranchStmt * branchStmt );
+                void previsit( ReturnStmt * returnStmt );
+                void previsit( ThrowStmt * throwStmt );
+                void previsit( CatchStmt * catchStmt );
+                void postvisit( CatchStmt * catchStmt );
+                void previsit( WaitForStmt * stmt );
+
+                void previsit( SingleInit * singleInit );
+                void previsit( ListInit * listInit );
+                void previsit( ConstructorInit * ctorInit );
+          private:
+                typedef std::list< Initializer * >::iterator InitIterator;
+
+                template< typename PtrType >
+                void handlePtrType( PtrType * type );
+
+                void fallbackInit( ConstructorInit * ctorInit );
+
+                Type * functionReturn = nullptr;
+                CurrentObject currentObject = nullptr;
+                bool inEnumDecl = false;
+        };
+
+        struct ResolveWithExprs : public WithIndexer, public WithGuards, public WithVisitorRef<ResolveWithExprs>, public WithShortCircuiting, public WithStmtsToAdd {
+                void previsit( FunctionDecl * );
+                void previsit( WithStmt * );
+
+                void resolveWithExprs( std::list< Expression * > & withExprs, std::list< Statement * > & newStmts );
+        };
+
+        void resolve( std::list< Declaration * > translationUnit ) {
+                PassVisitor<Resolver_old> resolver;
+                acceptAll( translationUnit, resolver );
+        }
+
+        void resolveDecl( Declaration * decl, const SymTab::Indexer & indexer ) {
+                PassVisitor<Resolver_old> resolver( indexer );
+                maybeAccept( decl, resolver );
+        }
+
+        namespace {
+                struct DeleteFinder_old : public WithShortCircuiting    {
+                        DeletedExpr * delExpr = nullptr;
+                        void previsit( DeletedExpr * expr ) {
+                                if ( delExpr ) visit_children = false;
+                                else delExpr = expr;
+                        }
+
+                        void previsit( Expression * ) {
+                                if ( delExpr ) visit_children = false;
+                        }
+                };
+        }
+
+        DeletedExpr * findDeletedExpr( Expression * expr ) {
+                PassVisitor<DeleteFinder_old> finder;
+                expr->accept( finder );
+                return finder.pass.delExpr;
+        }
+
+        namespace {
+                struct StripCasts_old {
+                        Expression * postmutate( CastExpr * castExpr ) {
+                                if ( castExpr->isGenerated && ResolvExpr::typesCompatible( castExpr->arg->result, castExpr->result, SymTab::Indexer() ) ) {
+                                        // generated cast is to the same type as its argument, so it's unnecessary -- remove it
+                                        Expression * expr = castExpr->arg;
+                                        castExpr->arg = nullptr;
+                                        std::swap( expr->env, castExpr->env );
+                                        return expr;
+                                }
+                                return castExpr;
+                        }
+
+                        static void strip( Expression *& expr ) {
+                                PassVisitor<StripCasts_old> stripper;
+                                expr = expr->acceptMutator( stripper );
+                        }
+                };
+
+                void finishExpr( Expression *& expr, const TypeEnvironment & env, TypeSubstitution * oldenv = nullptr ) {
+                        expr->env = oldenv ? oldenv->clone() : new TypeSubstitution;
+                        env.makeSubstitution( *expr->env );
+                        StripCasts_old::strip( expr ); // remove unnecessary casts that may be buried in an expression
+                }
+
+                void removeExtraneousCast( Expression *& expr, const SymTab::Indexer & indexer ) {
+                        if ( CastExpr * castExpr = dynamic_cast< CastExpr * >( expr ) ) {
+                                if ( typesCompatible( castExpr->arg->result, castExpr->result, indexer ) ) {
+                                        // cast is to the same type as its argument, so it's unnecessary -- remove it
+                                        expr = castExpr->arg;
+                                        castExpr->arg = nullptr;
+                                        std::swap( expr->env, castExpr->env );
+                                        delete castExpr;
+                                }
+                        }
+                }
+        } // namespace
+
+        namespace {
+                void findUnfinishedKindExpression(Expression * untyped, Alternative & alt, const SymTab::Indexer & indexer, const std::string & kindStr, std::function<bool(const Alternative &)> pred, ResolvMode mode = ResolvMode{} ) {
+                        assertf( untyped, "expected a non-null expression." );
+
+                        // xxx - this isn't thread-safe, but should work until we parallelize the resolver
+                        static unsigned recursion_level = 0;
+
+                        ++recursion_level;
+                        TypeEnvironment env;
+                        AlternativeFinder finder( indexer, env );
+                        finder.find( untyped, recursion_level == 1 ? mode.atTopLevel() : mode );
+                        --recursion_level;
+
+                        #if 0
+                        if ( finder.get_alternatives().size() != 1 ) {
+                                std::cerr << "untyped expr is ";
+                                untyped->print( std::cerr );
+                                std::cerr << std::endl << "alternatives are:";
+                                for ( const Alternative & alt : finder.get_alternatives() ) {
+                                        alt.print( std::cerr );
+                                } // for
+                        } // if
+                        #endif
+
+                        // produce filtered list of alternatives
+                        AltList candidates;
+                        for ( Alternative & alt : finder.get_alternatives() ) {
+                                if ( pred( alt ) ) {
+                                        candidates.push_back( std::move( alt ) );
+                                }
+                        }
+
+                        // produce invalid error if no candidates
+                        if ( candidates.empty() ) {
+                                SemanticError( untyped, toString( "No reasonable alternatives for ", kindStr, (kindStr != "" ? " " : ""), "expression: ") );
+                        }
+
+                        // search for cheapest candidate
+                        AltList winners;
+                        bool seen_undeleted = false;
+                        for ( unsigned i = 0; i < candidates.size(); ++i ) {
+                                int c = winners.empty() ? -1 : candidates[i].cost.compare( winners.front().cost );
+
+                                if ( c > 0 ) continue; // skip more expensive than winner
+
+                                if ( c < 0 ) {
+                                        // reset on new cheapest
+                                        seen_undeleted = ! findDeletedExpr( candidates[i].expr );
+                                        winners.clear();
+                                } else /* if ( c == 0 ) */ {
+                                        if ( findDeletedExpr( candidates[i].expr ) ) {
+                                                // skip deleted expression if already seen one equivalent-cost not
+                                                if ( seen_undeleted ) continue;
+                                        } else if ( ! seen_undeleted ) {
+                                                // replace list of equivalent-cost deleted expressions with one non-deleted
+                                                winners.clear();
+                                                seen_undeleted = true;
+                                        }
+                                }
+
+                                winners.emplace_back( std::move( candidates[i] ) );
+                        }
+
+                        // promote alternative.cvtCost to .cost
+                        // xxx - I don't know why this is done, but I'm keeping the behaviour from findMinCost
+                        for ( Alternative& winner : winners ) {
+                                winner.cost = winner.cvtCost;
+                        }
+
+                        // produce ambiguous errors, if applicable
+                        if ( winners.size() != 1 ) {
+                                std::ostringstream stream;
+                                stream << "Cannot choose between " << winners.size() << " alternatives for " << kindStr << (kindStr != "" ? " " : "") << "expression\n";
+                                untyped->print( stream );
+                                stream << " Alternatives are:\n";
+                                printAlts( winners, stream, 1 );
+                                SemanticError( untyped->location, stream.str() );
+                        }
+
+                        // single selected choice
+                        Alternative& choice = winners.front();
+
+                        // fail on only expression deleted
+                        if ( ! seen_undeleted ) {
+                                SemanticError( untyped->location, choice.expr, "Unique best alternative includes deleted identifier in " );
+                        }
+
+                        // xxx - check for ambiguous expressions
+
+                        // output selected choice
+                        alt = std::move( choice );
+                }
+
+                /// resolve `untyped` to the expression whose alternative satisfies `pred` with the lowest cost; kindStr is used for providing better error messages
+                void findKindExpression(Expression *& untyped, const SymTab::Indexer & indexer, const std::string & kindStr, std::function<bool(const Alternative &)> pred, ResolvMode mode = ResolvMode{}) {
+                        if ( ! untyped ) return;
+                        Alternative choice;
+                        findUnfinishedKindExpression( untyped, choice, indexer, kindStr, pred, mode );
+                        finishExpr( choice.expr, choice.env, untyped->env );
+                        delete untyped;
+                        untyped = choice.expr;
+                        choice.expr = nullptr;
+                }
+
+                bool standardAlternativeFilter( const Alternative & ) {
+                        // currently don't need to filter, under normal circumstances.
+                        // in the future, this may be useful for removing deleted expressions
+                        return true;
+                }
+        } // namespace
+
+        // used in resolveTypeof
+        Expression * resolveInVoidContext( Expression * expr, const SymTab::Indexer & indexer ) {
+                TypeEnvironment env;
+                return resolveInVoidContext( expr, indexer, env );
+        }
+
+        Expression * resolveInVoidContext( Expression * expr, const SymTab::Indexer & indexer, TypeEnvironment & env ) {
+                // it's a property of the language that a cast expression has either 1 or 0 interpretations; if it has 0
+                // interpretations, an exception has already been thrown.
+                assertf( expr, "expected a non-null expression." );
+
+                CastExpr * untyped = new CastExpr( expr ); // cast to void
+                untyped->location = expr->location;
+
+                // set up and resolve expression cast to void
+                Alternative choice;
+                findUnfinishedKindExpression( untyped, choice, indexer, "", standardAlternativeFilter, ResolvMode::withAdjustment() );
+                CastExpr * castExpr = strict_dynamic_cast< CastExpr * >( choice.expr );
+                assert( castExpr );
+                env = std::move( choice.env );
+
+                // clean up resolved expression
+                Expression * ret = castExpr->arg;
+                castExpr->arg = nullptr;
+
+                // unlink the arg so that it isn't deleted twice at the end of the program
+                untyped->arg = nullptr;
+                return ret;
+        }
+
+        void findVoidExpression( Expression *& untyped, const SymTab::Indexer & indexer ) {
+                resetTyVarRenaming();
+                TypeEnvironment env;
+                Expression * newExpr = resolveInVoidContext( untyped, indexer, env );
+                finishExpr( newExpr, env, untyped->env );
+                delete untyped;
+                untyped = newExpr;
+        }
+
+        void findSingleExpression( Expression *& untyped, const SymTab::Indexer & indexer ) {
+                findKindExpression( untyped, indexer, "", standardAlternativeFilter );
+        }
+
+        void findSingleExpression( Expression *& untyped, Type * type, const SymTab::Indexer & indexer ) {
+                assert( untyped && type );
+                // transfer location to generated cast for error purposes
+                CodeLocation location = untyped->location;
+                untyped = new CastExpr( untyped, type );
+                untyped->location = location;
+                findSingleExpression( untyped, indexer );
+                removeExtraneousCast( untyped, indexer );
+        }
+
+        namespace {
+                bool isIntegralType( const Alternative & alt ) {
+                        Type * type = alt.expr->result;
+                        if ( dynamic_cast< EnumInstType * >( type ) ) {
+                                return true;
+                        } else if ( BasicType * bt = dynamic_cast< BasicType * >( type ) ) {
+                                return bt->isInteger();
+                        } else if ( dynamic_cast< ZeroType* >( type ) != nullptr || dynamic_cast< OneType* >( type ) != nullptr ) {
+                                return true;
+                        } else {
+                                return false;
+                        } // if
+                }
+
+                void findIntegralExpression( Expression *& untyped, const SymTab::Indexer & indexer ) {
+                        findKindExpression( untyped, indexer, "condition", isIntegralType );
+                }
+        }
+
+
+        bool isStructOrUnion( const Alternative & alt ) {
+                Type * t = alt.expr->result->stripReferences();
+                return dynamic_cast< StructInstType * >( t ) || dynamic_cast< UnionInstType * >( t );
+        }
+
+        void resolveWithExprs( std::list< Declaration * > & translationUnit ) {
+                PassVisitor<ResolveWithExprs> resolver;
+                acceptAll( translationUnit, resolver );
+        }
+
+        void ResolveWithExprs::resolveWithExprs( std::list< Expression * > & withExprs, std::list< Statement * > & newStmts ) {
+                for ( Expression *& expr : withExprs )  {
+                        // only struct- and union-typed expressions are viable candidates
+                        findKindExpression( expr, indexer, "with statement", isStructOrUnion );
+
+                        // if with expression might be impure, create a temporary so that it is evaluated once
+                        if ( Tuples::maybeImpure( expr ) ) {
+                                static UniqueName tmpNamer( "_with_tmp_" );
+                                ObjectDecl * tmp = ObjectDecl::newObject( tmpNamer.newName(), expr->result->clone(), new SingleInit( expr ) );
+                                expr = new VariableExpr( tmp );
+                                newStmts.push_back( new DeclStmt( tmp ) );
+                                if ( InitTweak::isConstructable( tmp->type ) ) {
+                                        // generate ctor/dtor and resolve them
+                                        tmp->init = InitTweak::genCtorInit( tmp );
+                                        tmp->accept( *visitor );
+                                }
+                        }
+                }
+        }
+
+        void ResolveWithExprs::previsit( WithStmt * withStmt ) {
+                resolveWithExprs( withStmt->exprs, stmtsToAddBefore );
+        }
+
+        void ResolveWithExprs::previsit( FunctionDecl * functionDecl ) {
+                {
+                        // resolve with-exprs with parameters in scope and add any newly generated declarations to the
+                        // front of the function body.
+                        auto guard = makeFuncGuard( [this]() { indexer.enterScope(); }, [this](){ indexer.leaveScope(); } );
+                        indexer.addFunctionType( functionDecl->type );
+                        std::list< Statement * > newStmts;
+                        resolveWithExprs( functionDecl->withExprs, newStmts );
+                        if ( functionDecl->statements ) {
+                                functionDecl->statements->kids.splice( functionDecl->statements->kids.begin(), newStmts );
+                        } else {
+                                assertf( functionDecl->withExprs.empty() && newStmts.empty(), "Function %s without a body has with-clause and/or generated with declarations.", functionDecl->name.c_str() );
+                        }
+                }
+        }
+
+        void Resolver_old::previsit( ObjectDecl * objectDecl ) {
+                // To handle initialization of routine pointers, e.g., int (*fp)(int) = foo(), means that
+                // class-variable initContext is changed multiple time because the LHS is analysed twice.
+                // The second analysis changes initContext because of a function type can contain object
+                // declarations in the return and parameter types. So each value of initContext is
+                // retained, so the type on the first analysis is preserved and used for selecting the RHS.
+                GuardValue( currentObject );
+                currentObject = CurrentObject( objectDecl->get_type() );
+                if ( inEnumDecl && dynamic_cast< EnumInstType * >( objectDecl->get_type() ) ) {
+                        // enumerator initializers should not use the enum type to initialize, since
+                        // the enum type is still incomplete at this point. Use signed int instead.
+                        // TODO: BasicType::SignedInt may not longer be true
+                        currentObject = CurrentObject( new BasicType( Type::Qualifiers(), BasicType::SignedInt ) );
+                }
+        }
+
+        template< typename PtrType >
+        void Resolver_old::handlePtrType( PtrType * type ) {
+                if ( type->get_dimension() ) {
+                        findSingleExpression( type->dimension, Validate::SizeType->clone(), indexer );
+                }
+        }
+
+        void Resolver_old::previsit( ArrayType * at ) {
+                handlePtrType( at );
+        }
+
+        void Resolver_old::previsit( PointerType * pt ) {
+                handlePtrType( pt );
+        }
+
+        void Resolver_old::previsit( FunctionDecl * functionDecl ) {
+#if 0
+                std::cerr << "resolver visiting functiondecl ";
+                functionDecl->print( std::cerr );
+                std::cerr << std::endl;
+#endif
+                GuardValue( functionReturn );
+                functionReturn = ResolvExpr::extractResultType( functionDecl->type );
+        }
+
+        void Resolver_old::postvisit( FunctionDecl * functionDecl ) {
+                // default value expressions have an environment which shouldn't be there and trips up
+                // later passes.
+                // xxx - it might be necessary to somehow keep the information from this environment, but I
+                // can't currently see how it's useful.
+                for ( Declaration * d : functionDecl->type->parameters ) {
+                        if ( ObjectDecl * obj = dynamic_cast< ObjectDecl * >( d ) ) {
+                                if ( SingleInit * init = dynamic_cast< SingleInit * >( obj->init ) ) {
+                                        delete init->value->env;
+                                        init->value->env = nullptr;
+                                }
+                        }
+                }
+        }
+
+        void Resolver_old::previsit( EnumDecl * ) {
+                // in case we decide to allow nested enums
+                GuardValue( inEnumDecl );
+                inEnumDecl = true;
+        }
+
+        void Resolver_old::previsit( StaticAssertDecl * assertDecl ) {
+                findIntegralExpression( assertDecl->condition, indexer );
+        }
+
+        void Resolver_old::previsit( ExprStmt * exprStmt ) {
+                visit_children = false;
+                assertf( exprStmt->expr, "ExprStmt has null Expression in resolver" );
+                findVoidExpression( exprStmt->expr, indexer );
+        }
+
+        void Resolver_old::previsit( AsmExpr * asmExpr ) {
+                visit_children = false;
+                findVoidExpression( asmExpr->operand, indexer );
+        }
+
+        void Resolver_old::previsit( AsmStmt * asmStmt ) {
+                visit_children = false;
+                acceptAll( asmStmt->get_input(), *visitor );
+                acceptAll( asmStmt->get_output(), *visitor );
+        }
+
+        void Resolver_old::previsit( IfStmt * ifStmt ) {
+                findIntegralExpression( ifStmt->condition, indexer );
+        }
+
+        void Resolver_old::previsit( WhileDoStmt * whileDoStmt ) {
+                findIntegralExpression( whileDoStmt->condition, indexer );
+        }
+
+        void Resolver_old::previsit( ForStmt * forStmt ) {
+                if ( forStmt->condition ) {
+                        findIntegralExpression( forStmt->condition, indexer );
+                } // if
+
+                if ( forStmt->increment ) {
+                        findVoidExpression( forStmt->increment, indexer );
+                } // if
+        }
+
+        void Resolver_old::previsit( SwitchStmt * switchStmt ) {
+                GuardValue( currentObject );
+                findIntegralExpression( switchStmt->condition, indexer );
+
+                currentObject = CurrentObject( switchStmt->condition->result );
+        }
+
+        void Resolver_old::previsit( CaseStmt * caseStmt ) {
+                if ( caseStmt->condition ) {
+                        std::list< InitAlternative > initAlts = currentObject.getOptions();
+                        assertf( initAlts.size() == 1, "SwitchStmt did not correctly resolve an integral expression." );
+                        // must remove cast from case statement because RangeExpr cannot be cast.
+                        Expression * newExpr = new CastExpr( caseStmt->condition, initAlts.front().type->clone() );
+                        findSingleExpression( newExpr, indexer );
+                        // case condition cannot have a cast in C, so it must be removed, regardless of whether it performs a conversion.
+                        // Ideally we would perform the conversion internally here.
+                        if ( CastExpr * castExpr = dynamic_cast< CastExpr * >( newExpr ) ) {
+                                newExpr = castExpr->arg;
+                                castExpr->arg = nullptr;
+                                std::swap( newExpr->env, castExpr->env );
+                                delete castExpr;
+                        }
+                        caseStmt->condition = newExpr;
+                }
+        }
+
+        void Resolver_old::previsit( BranchStmt * branchStmt ) {
+                visit_children = false;
+                // must resolve the argument for a computed goto
+                if ( branchStmt->get_type() == BranchStmt::Goto ) { // check for computed goto statement
+                        if ( branchStmt->computedTarget ) {
+                                // computed goto argument is void *
+                                findSingleExpression( branchStmt->computedTarget, new PointerType( Type::Qualifiers(), new VoidType( Type::Qualifiers() ) ), indexer );
+                        } // if
+                } // if
+        }
+
+        void Resolver_old::previsit( ReturnStmt * returnStmt ) {
+                visit_children = false;
+                if ( returnStmt->expr ) {
+                        findSingleExpression( returnStmt->expr, functionReturn->clone(), indexer );
+                } // if
+        }
+
+        void Resolver_old::previsit( ThrowStmt * throwStmt ) {
+                visit_children = false;
+                // TODO: Replace *exception type with &exception type.
+                if ( throwStmt->get_expr() ) {
+                        const StructDecl * exception_decl = indexer.lookupStruct( "__cfaehm_base_exception_t" );
+                        assert( exception_decl );
+                        Type * exceptType = new PointerType( noQualifiers, new StructInstType( noQualifiers, const_cast<StructDecl *>(exception_decl) ) );
+                        findSingleExpression( throwStmt->expr, exceptType, indexer );
+                }
+        }
+
+        void Resolver_old::previsit( CatchStmt * catchStmt ) {
+                // Until we are very sure this invarent (ifs that move between passes have then)
+                // holds, check it. This allows a check for when to decode the mangling.
+                if ( IfStmt * ifStmt = dynamic_cast<IfStmt *>( catchStmt->body ) ) {
+                        assert( ifStmt->then );
+                }
+                // Encode the catchStmt so the condition can see the declaration.
+                if ( catchStmt->cond ) {
+                        IfStmt * ifStmt = new IfStmt( catchStmt->cond, nullptr, catchStmt->body );
+                        catchStmt->cond = nullptr;
+                        catchStmt->body = ifStmt;
+                }
+        }
+
+        void Resolver_old::postvisit( CatchStmt * catchStmt ) {
+                // Decode the catchStmt so everything is stored properly.
+                IfStmt * ifStmt = dynamic_cast<IfStmt *>( catchStmt->body );
+                if ( nullptr != ifStmt && nullptr == ifStmt->then ) {
+                        assert( ifStmt->condition );
+                        assert( ifStmt->else_ );
+                        catchStmt->cond = ifStmt->condition;
+                        catchStmt->body = ifStmt->else_;
+                        ifStmt->condition = nullptr;
+                        ifStmt->else_ = nullptr;
+                        delete ifStmt;
+                }
+        }
+
         template< typename iterator_t >
         inline bool advance_to_mutex( iterator_t & it, const iterator_t & end ) {
@@ -59 +610 @@
                 return it != end;
         }
+
+        void Resolver_old::previsit( WaitForStmt * stmt ) {
+                visit_children = false;
+
+                // Resolve all clauses first
+                for( auto& clause : stmt->clauses ) {
+
+                        TypeEnvironment env;
+                        AlternativeFinder funcFinder( indexer, env );
+
+                        // Find all alternatives for a function in canonical form
+                        funcFinder.findWithAdjustment( clause.target.function );
+
+                        if ( funcFinder.get_alternatives().empty() ) {
+                                stringstream ss;
+                                ss << "Use of undeclared indentifier '";
+                                ss << strict_dynamic_cast<NameExpr*>( clause.target.function )->name;
+                                ss << "' in call to waitfor";
+                                SemanticError( stmt->location, ss.str() );
+                        }
+
+                        if(clause.target.arguments.empty()) {
+                                SemanticError( stmt->location, "Waitfor clause must have at least one mutex parameter");
+                        }
+
+                        // Find all alternatives for all arguments in canonical form
+                        std::vector< AlternativeFinder > argAlternatives;
+                        funcFinder.findSubExprs( clause.target.arguments.begin(), clause.target.arguments.end(), back_inserter( argAlternatives ) );
+
+                        // List all combinations of arguments
+                        std::vector< AltList > possibilities;
+                        combos( argAlternatives.begin(), argAlternatives.end(), back_inserter( possibilities ) );
+
+                        AltList                func_candidates;
+                        std::vector< AltList > args_candidates;
+
+                        // For every possible function :
+                        //      try matching the arguments to the parameters
+                        //      not the other way around because we have more arguments than parameters
+                        SemanticErrorException errors;
+                        for ( Alternative & func : funcFinder.get_alternatives() ) {
+                                try {
+                                        PointerType * pointer = dynamic_cast< PointerType* >( func.expr->get_result()->stripReferences() );
+                                        if( !pointer ) {
+                                                SemanticError( func.expr->get_result(), "candidate not viable: not a pointer type\n" );
+                                        }
+
+                                        FunctionType * function = dynamic_cast< FunctionType* >( pointer->get_base() );
+                                        if( !function ) {
+                                                SemanticError( pointer->get_base(), "candidate not viable: not a function type\n" );
+                                        }
+
+
+                                        {
+                                                auto param     = function->parameters.begin();
+                                                auto param_end = function->parameters.end();
+
+                                                if( !advance_to_mutex( param, param_end ) ) {
+                                                        SemanticError(function, "candidate function not viable: no mutex parameters\n");
+                                                }
+                                        }
+
+                                        Alternative newFunc( func );
+                                        // Strip reference from function
+                                        referenceToRvalueConversion( newFunc.expr, newFunc.cost );
+
+                                        // For all the set of arguments we have try to match it with the parameter of the current function alternative
+                                        for ( auto & argsList : possibilities ) {
+
+                                                try {
+                                                        // Declare data structures need for resolution
+                                                        OpenVarSet openVars;
+                                                        AssertionSet resultNeed, resultHave;
+                                                        TypeEnvironment resultEnv( func.env );
+                                                        makeUnifiableVars( function, openVars, resultNeed );
+                                                        // add all type variables as open variables now so that those not used in the parameter
+                                                        // list are still considered open.
+                                                        resultEnv.add( function->forall );
+
+                                                        // Load type variables from arguemnts into one shared space
+                                                        simpleCombineEnvironments( argsList.begin(), argsList.end(), resultEnv );
+
+                                                        // Make sure we don't widen any existing bindings
+                                                        resultEnv.forbidWidening();
+
+                                                        // Find any unbound type variables
+                                                        resultEnv.extractOpenVars( openVars );
+
+                                                        auto param     = function->parameters.begin();
+                                                        auto param_end = function->parameters.end();
+
+                                                        int n_mutex_param = 0;
+
+                                                        // For every arguments of its set, check if it matches one of the parameter
+                                                        // The order is important
+                                                        for( auto & arg : argsList ) {
+
+                                                                // Ignore non-mutex arguments
+                                                                if( !advance_to_mutex( param, param_end ) ) {
+                                                                        // We ran out of parameters but still have arguments
+                                                                        // this function doesn't match
+                                                                        SemanticError( function, toString("candidate function not viable: too many mutex arguments, expected ", n_mutex_param, "\n" ));
+                                                                }
+
+                                                                n_mutex_param++;
+
+                                                                // Check if the argument matches the parameter type in the current scope
+                                                                if( ! unify( arg.expr->get_result(), (*param)->get_type(), resultEnv, resultNeed, resultHave, openVars, this->indexer ) ) {
+                                                                        // Type doesn't match
+                                                                        stringstream ss;
+                                                                        ss << "candidate function not viable: no known convertion from '";
+                                                                        (*param)->get_type()->print( ss );
+                                                                        ss << "' to '";
+                                                                        arg.expr->get_result()->print( ss );
+                                                                        ss << "' with env '";
+                                                                        resultEnv.print(ss);
+                                                                        ss << "'\n";
+                                                                        SemanticError( function, ss.str() );
+                                                                }
+
+                                                                param++;
+                                                        }
+
+                                                        // All arguments match !
+
+                                                        // Check if parameters are missing
+                                                        if( advance_to_mutex( param, param_end ) ) {
+                                                                do {
+                                                                        n_mutex_param++;
+                                                                        param++;
+                                                                } while( advance_to_mutex( param, param_end ) );
+
+                                                                // We ran out of arguments but still have parameters left
+                                                                // this function doesn't match
+                                                                SemanticError( function, toString("candidate function not viable: too few mutex arguments, expected ", n_mutex_param, "\n" ));
+                                                        }
+
+                                                        // All parameters match !
+
+                                                        // Finish the expressions to tie in the proper environments
+                                                        finishExpr( newFunc.expr, resultEnv );
+                                                        for( Alternative & alt : argsList ) {
+                                                                finishExpr( alt.expr, resultEnv );
+                                                        }
+
+                                                        // This is a match store it and save it for later
+                                                        func_candidates.push_back( newFunc );
+                                                        args_candidates.push_back( argsList );
+
+                                                }
+                                                catch( SemanticErrorException & e ) {
+                                                        errors.append( e );
+                                                }
+                                        }
+                                }
+                                catch( SemanticErrorException & e ) {
+                                        errors.append( e );
+                                }
+                        }
+
+                        // Make sure we got the right number of arguments
+                        if( func_candidates.empty() )    { SemanticErrorException top( stmt->location, "No alternatives for function in call to waitfor"  ); top.append( errors ); throw top; }
+                        if( args_candidates.empty() )    { SemanticErrorException top( stmt->location, "No alternatives for arguments in call to waitfor" ); top.append( errors ); throw top; }
+                        if( func_candidates.size() > 1 ) { SemanticErrorException top( stmt->location, "Ambiguous function in call to waitfor"            ); top.append( errors ); throw top; }
+                        if( args_candidates.size() > 1 ) { SemanticErrorException top( stmt->location, "Ambiguous arguments in call to waitfor"           ); top.append( errors ); throw top; }
+                        // TODO: need to use findDeletedExpr to ensure no deleted identifiers are used.
+
+                        // Swap the results from the alternative with the unresolved values.
+                        // Alternatives will handle deletion on destruction
+                        std::swap( clause.target.function, func_candidates.front().expr );
+                        for( auto arg_pair : group_iterate( clause.target.arguments, args_candidates.front() ) ) {
+                                std::swap ( std::get<0>( arg_pair), std::get<1>( arg_pair).expr );
+                        }
+
+                        // Resolve the conditions as if it were an IfStmt
+                        // Resolve the statments normally
+                        findSingleExpression( clause.condition, this->indexer );
+                        clause.statement->accept( *visitor );
+                }
+
+
+                if( stmt->timeout.statement ) {
+                        // Resolve the timeout as an size_t for now
+                        // Resolve the conditions as if it were an IfStmt
+                        // Resolve the statments normally
+                        findSingleExpression( stmt->timeout.time, new BasicType( noQualifiers, BasicType::LongLongUnsignedInt ), this->indexer );
+                        findSingleExpression( stmt->timeout.condition, this->indexer );
+                        stmt->timeout.statement->accept( *visitor );
+                }
+
+                if( stmt->orelse.statement ) {
+                        // Resolve the conditions as if it were an IfStmt
+                        // Resolve the statments normally
+                        findSingleExpression( stmt->orelse.condition, this->indexer );
+                        stmt->orelse.statement->accept( *visitor );
+                }
+        }
+
+        bool isCharType( Type * t ) {
+                if ( BasicType * bt = dynamic_cast< BasicType * >( t ) ) {
+                        return bt->get_kind() == BasicType::Char || bt->get_kind() == BasicType::SignedChar ||
+                                bt->get_kind() == BasicType::UnsignedChar;
+                }
+                return false;
+        }
+
+        void Resolver_old::previsit( SingleInit * singleInit ) {
+                visit_children = false;
+                // resolve initialization using the possibilities as determined by the currentObject cursor
+                Expression * newExpr = new UntypedInitExpr( singleInit->value, currentObject.getOptions() );
+                findSingleExpression( newExpr, indexer );
+                InitExpr * initExpr = strict_dynamic_cast< InitExpr * >( newExpr );
+
+                // move cursor to the object that is actually initialized
+                currentObject.setNext( initExpr->get_designation() );
+
+                // discard InitExpr wrapper and retain relevant pieces
+                newExpr = initExpr->expr;
+                initExpr->expr = nullptr;
+                std::swap( initExpr->env, newExpr->env );
+                // InitExpr may have inferParams in the case where the expression specializes a function
+                // pointer, and newExpr may already have inferParams of its own, so a simple swap is not
+                // sufficient.
+                newExpr->spliceInferParams( initExpr );
+                delete initExpr;
+
+                // get the actual object's type (may not exactly match what comes back from the resolver
+                // due to conversions)
+                Type * initContext = currentObject.getCurrentType();
+
+                removeExtraneousCast( newExpr, indexer );
+
+                // check if actual object's type is char[]
+                if ( ArrayType * at = dynamic_cast< ArrayType * >( initContext ) ) {
+                        if ( isCharType( at->get_base() ) ) {
+                                // check if the resolved type is char *
+                                if ( PointerType * pt = dynamic_cast< PointerType *>( newExpr->get_result() ) ) {
+                                        if ( isCharType( pt->get_base() ) ) {
+                                                if ( CastExpr * ce = dynamic_cast< CastExpr * >( newExpr ) ) {
+                                                        // strip cast if we're initializing a char[] with a char *,
+                                                        // e.g.  char x[] = "hello";
+                                                        newExpr = ce->get_arg();
+                                                        ce->set_arg( nullptr );
+                                                        std::swap( ce->env, newExpr->env );
+                                                        delete ce;
+                                                }
+                                        }
+                                }
+                        }
+                }
+
+                // set initializer expr to resolved express
+                singleInit->value = newExpr;
+
+                // move cursor to next object in preparation for next initializer
+                currentObject.increment();
+        }
+
+        void Resolver_old::previsit( ListInit * listInit ) {
+                visit_children = false;
+                // move cursor into brace-enclosed initializer-list
+                currentObject.enterListInit();
+                // xxx - fix this so that the list isn't copied, iterator should be used to change current
+                // element
+                std::list<Designation *> newDesignations;
+                for ( auto p : group_iterate(listInit->get_designations(), listInit->get_initializers()) ) {
+                        // iterate designations and initializers in pairs, moving the cursor to the current
+                        // designated object and resolving the initializer against that object.
+                        Designation * des = std::get<0>(p);
+                        Initializer * init = std::get<1>(p);
+                        newDesignations.push_back( currentObject.findNext( des ) );
+                        init->accept( *visitor );
+                }
+                // set the set of 'resolved' designations and leave the brace-enclosed initializer-list
+                listInit->get_designations() = newDesignations; // xxx - memory management
+                currentObject.exitListInit();
+
+                // xxx - this part has not be folded into CurrentObject yet
+                // } else if ( TypeInstType * tt = dynamic_cast< TypeInstType * >( initContext ) ) {
+                //      Type * base = tt->get_baseType()->get_base();
+                //      if ( base ) {
+                //              // know the implementation type, so try using that as the initContext
+                //              ObjectDecl tmpObj( "", Type::StorageClasses(), LinkageSpec::Cforall, nullptr, base->clone(), nullptr );
+                //              currentObject = &tmpObj;
+                //              visit( listInit );
+                //      } else {
+                //              // missing implementation type -- might be an unknown type variable, so try proceeding with the current init context
+                //              Parent::visit( listInit );
+                //      }
+                // } else {
+        }
+
+        // ConstructorInit - fall back on C-style initializer
+        void Resolver_old::fallbackInit( ConstructorInit * ctorInit ) {
+                // could not find valid constructor, or found an intrinsic constructor
+                // fall back on C-style initializer
+                delete ctorInit->get_ctor();
+                ctorInit->set_ctor( nullptr );
+                delete ctorInit->get_dtor();
+                ctorInit->set_dtor( nullptr );
+                maybeAccept( ctorInit->get_init(), *visitor );
+        }
+
+        // needs to be callable from outside the resolver, so this is a standalone function
+        void resolveCtorInit( ConstructorInit * ctorInit, const SymTab::Indexer & indexer ) {
+                assert( ctorInit );
+                PassVisitor<Resolver_old> resolver( indexer );
+                ctorInit->accept( resolver );
+        }
+
+        void resolveStmtExpr( StmtExpr * stmtExpr, const SymTab::Indexer & indexer ) {
+                assert( stmtExpr );
+                PassVisitor<Resolver_old> resolver( indexer );
+                stmtExpr->accept( resolver );
+                stmtExpr->computeResult();
+                // xxx - aggregate the environments from all statements? Possibly in AlternativeFinder instead?
+        }
+
+        void Resolver_old::previsit( ConstructorInit * ctorInit ) {
+                visit_children = false;
+                // xxx - fallback init has been removed => remove fallbackInit function and remove complexity from FixInit and remove C-init from ConstructorInit
+                maybeAccept( ctorInit->ctor, *visitor );
+                maybeAccept( ctorInit->dtor, *visitor );
+
+                // found a constructor - can get rid of C-style initializer
+                delete ctorInit->init;
+                ctorInit->init = nullptr;
+
+                // intrinsic single parameter constructors and destructors do nothing. Since this was
+                // implicitly generated, there's no way for it to have side effects, so get rid of it
+                // to clean up generated code.
+                if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->ctor ) ) {
+                        delete ctorInit->ctor;
+                        ctorInit->ctor = nullptr;
+                }
+
+                if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->dtor ) ) {
+                        delete ctorInit->dtor;
+                        ctorInit->dtor = nullptr;
+                }
+
+                // xxx - todo -- what about arrays?
+                // if ( dtor == nullptr && InitTweak::isIntrinsicCallStmt( ctorInit->get_ctor() ) ) {
+                //      // can reduce the constructor down to a SingleInit using the
+                //      // second argument from the ctor call, since
+                //      delete ctorInit->get_ctor();
+                //      ctorInit->set_ctor( nullptr );
+
+                //      Expression * arg =
+                //      ctorInit->set_init( new SingleInit( arg ) );
+                // }
+        }
+
+        ///////////////////////////////////////////////////////////////////////////
+        //
+        // *** NEW RESOLVER ***
+        //
+        ///////////////////////////////////////////////////////////////////////////
 
         namespace {