source: src/SymTab/Indexer.cc @ fdae913

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Indexer.cc --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 21:37:33 2015
// Last Modified By : Aaron B. Moss
// Last Modified On : Fri Mar  8 13:55:00 2019
// Update Count     : 21
//

#include "Indexer.h"

#include <cassert>                 // for assert, strict_dynamic_cast
#include <string>                  // for string, operator<<, operator!=
#include <memory>                  // for shared_ptr, make_shared
#include <unordered_map>           // for operator!=, unordered_map<>::const...
#include <unordered_set>           // for unordered_set
#include <utility>                 // for pair, make_pair, move

#include "CodeGen/OperatorTable.h" // for isCtorDtor, isCtorDtorAssign
#include "Common/SemanticError.h"  // for SemanticError
#include "Common/utility.h"        // for cloneAll
#include "Common/Stats/Counter.h"  // for counters
#include "GenPoly/GenPoly.h"       // for getFunctionType
#include "InitTweak/InitTweak.h"   // for isConstructor, isCopyFunction, isC...
#include "Mangler.h"               // for Mangler
#include "Parser/LinkageSpec.h"    // for isMangled, isOverridable, Spec
#include "ResolvExpr/typeops.h"    // for typesCompatible
#include "SynTree/Constant.h"      // for Constant
#include "SynTree/Declaration.h"   // for DeclarationWithType, FunctionDecl
#include "SynTree/Expression.h"    // for Expression, ImplicitCopyCtorExpr
#include "SynTree/Initializer.h"   // for Initializer
#include "SynTree/Statement.h"     // for CompoundStmt, Statement, ForStmt (...
#include "SynTree/Type.h"          // for Type, StructInstType, UnionInstType

namespace SymTab {

        // Statistics block
        namespace {
                static inline auto stats() {
                        using namespace Stats::Counters;
                        static auto group   = build<CounterGroup>("Indexers");
                        static struct {
                                SimpleCounter * count;
                                AverageCounter<double> * size;
                                SimpleCounter * new_scopes;
                                SimpleCounter * lazy_scopes;
                                AverageCounter<double> * avg_scope_depth;
                                MaxCounter<size_t> * max_scope_depth;
                                SimpleCounter * add_calls;
                                SimpleCounter * lookup_calls;
                                SimpleCounter * map_lookups;
                                SimpleCounter * map_mutations;
                        } ret = {
                                .count   = build<SimpleCounter>("Count", group),
                                .size    = build<AverageCounter<double>>("Average Size", group),
                                .new_scopes = build<SimpleCounter>("Scopes", group),
                                .lazy_scopes = build<SimpleCounter>("Lazy Scopes", group),
                                .avg_scope_depth = build<AverageCounter<double>>("Average Scope", group),
                                .max_scope_depth = build<MaxCounter<size_t>>("Max Scope", group),
                                .add_calls = build<SimpleCounter>("Add Calls", group),
                                .lookup_calls = build<SimpleCounter>("Lookup Calls", group),
                                .map_lookups = build<SimpleCounter>("Map Lookups", group),
                                .map_mutations = build<SimpleCounter>("Map Mutations", group)
                        };
                        return ret;
                }
        }

        void Indexer::removeSpecialOverrides( const std::string &id, std::list< IdData > & out ) const {
                // only need to perform this step for constructors, destructors, and assignment functions
                if ( ! CodeGen::isCtorDtorAssign( id ) ) return;

                // helpful data structure to organize properties for a type
                struct ValueType {
                        struct DeclBall { // properties for this particular decl
                                IdData decl;
                                bool isUserDefinedFunc;
                                bool isCopyFunc;
                        };
                        // properties for this type
                        bool existsUserDefinedCopyFunc = false;    // user-defined copy ctor found
                        BaseSyntaxNode * deleteStmt = nullptr;     // non-null if a user-defined function is found
                        std::list< DeclBall > decls;

                        // another FunctionDecl for the current type was found - determine
                        // if it has special properties and update data structure accordingly
                        ValueType & operator+=( IdData data ) {
                                DeclarationWithType * function = data.id;
                                bool isUserDefinedFunc = ! LinkageSpec::isOverridable( function->linkage );
                                bool isCopyFunc = InitTweak::isCopyFunction( function, function->name );
                                decls.push_back( DeclBall{ data, isUserDefinedFunc, isCopyFunc } );
                                existsUserDefinedCopyFunc |= (isUserDefinedFunc && isCopyFunc);
                                if ( isUserDefinedFunc && ! deleteStmt ) {
                                        // any user-defined function can act as an implicit delete statement for generated constructors.
                                        // a delete stmt should not act as an implicit delete statement.
                                        deleteStmt = data.id;
                                }
                                return *this;
                        }
                }; // ValueType

                std::list< IdData > copy;
                copy.splice( copy.end(), out );

                // organize discovered declarations by type
                std::unordered_map< std::string, ValueType > funcMap;
                for ( auto decl : copy ) {
                        if ( FunctionDecl * function = dynamic_cast< FunctionDecl * >( decl.id ) ) {
                                std::list< DeclarationWithType * > & params = function->type->parameters;
                                assert( ! params.empty() );
                                // use base type of pointer, so that qualifiers on the pointer type aren't considered.
                                Type * base = InitTweak::getPointerBase( params.front()->get_type() );
                                assert( base );
                                funcMap[ Mangler::mangle( base ) ] += decl;
                        } else {
                                out.push_back( decl );
                        }
                }

                // if a type contains user defined ctor/dtor/assign, then special rules trigger, which 
                // determinethe set of ctor/dtor/assign that can be used  by the requester. In particular, 
                // if the user defines a default ctor, then the generated default ctor is unavailable, 
                // likewise for copy ctor and dtor. If the user defines any ctor/dtor, then no generated 
                // field ctors are available. If the user defines any ctor then the generated default ctor 
                // is unavailable (intrinsic default ctor must be overridden exactly). If the user defines 
                // anything that looks like a copy constructor, then the generated copy constructor is 
                // unavailable, and likewise for the assignment operator.
                for ( std::pair< const std::string, ValueType > & pair : funcMap ) {
                        ValueType & val = pair.second;
                        for ( ValueType::DeclBall ball : val.decls ) {
                                bool isNotUserDefinedFunc = ! ball.isUserDefinedFunc && ball.decl.id->linkage != LinkageSpec::Intrinsic;
                                bool isCopyFunc = ball.isCopyFunc;
                                bool existsUserDefinedCopyFunc = val.existsUserDefinedCopyFunc;

                                // only implicitly delete non-user defined functions that are not intrinsic, and are
                                // not copy functions (assignment or copy constructor). If a  user-defined copy 
                                // function exists, do not pass along the non-user-defined copy functions since 
                                // signatures do not have to match, and the generated functions will often be 
                                // cheaper.
                                if ( isNotUserDefinedFunc ) {
                                        if ( isCopyFunc ) {
                                                // Skip over non-user-defined copy functions when there is a user-defined 
                                                // copy function. Since their signatures do not have to be exact, deleting 
                                                // them is the wrong choice.
                                                if ( existsUserDefinedCopyFunc ) continue;
                                        } else {
                                                // delete non-user-defined non-copy functions if applicable.
                                                // deleteStmt will be non-null only if a user-defined function is found.
                                                ball.decl.deleteStmt = val.deleteStmt;
                                        }
                                }
                                out.push_back( ball.decl );
                        }
                }
        }

        Indexer::Indexer() 
        : idTable(), typeTable(), structTable(), enumTable(), unionTable(), traitTable(), 
          prevScope(), scope( 0 ), repScope( 0 ) { ++*stats().count; }

        Indexer::~Indexer() {
                stats().size->push( idTable ? idTable->size() : 0 );
        }

        void Indexer::lazyInitScope() {
                if ( repScope < scope ) {
                        ++*stats().lazy_scopes;
                        // create rollback
                        prevScope = std::make_shared<Indexer>( *this );
                        // update repScope
                        repScope = scope;
                }
        }

        void Indexer::enterScope() {
                ++scope;

                ++*stats().new_scopes;
                stats().avg_scope_depth->push( scope );
                stats().max_scope_depth->push( scope );
        }

        void Indexer::leaveScope() {
                if ( repScope == scope ) {
                        Ptr prev = prevScope;           // make sure prevScope stays live
                        *this = std::move(*prevScope);  // replace with previous scope
                }

                --scope;
        }

        void Indexer::lookupId( const std::string &id, std::list< IdData > &out ) const {
                ++*stats().lookup_calls;
                if ( ! idTable ) return;

                ++*stats().map_lookups;
                auto decls = idTable->find( id );
                if ( decls == idTable->end() ) return;

                for ( auto decl : *(decls->second) ) {
                        out.push_back( decl.second );
                }
                
                // some special functions, e.g. constructors and destructors
                // remove autogenerated functions when they are defined so that
                // they can never be matched
                removeSpecialOverrides( id, out );
        }

        NamedTypeDecl *Indexer::lookupType( const std::string &id ) const {
                ++*stats().lookup_calls;
                if ( ! typeTable ) return nullptr;
                ++*stats().map_lookups;
                auto it = typeTable->find( id );
                return it == typeTable->end() ? nullptr : it->second.decl;
        }

        StructDecl *Indexer::lookupStruct( const std::string &id ) const {
                ++*stats().lookup_calls;
                if ( ! structTable ) return nullptr;
                ++*stats().map_lookups;
                auto it = structTable->find( id );
                return it == structTable->end() ? nullptr : it->second.decl;
        }

        EnumDecl *Indexer::lookupEnum( const std::string &id ) const {
                ++*stats().lookup_calls;
                if ( ! enumTable ) return nullptr;
                ++*stats().map_lookups;
                auto it = enumTable->find( id );
                return it == enumTable->end() ? nullptr : it->second.decl;
        }

        UnionDecl *Indexer::lookupUnion( const std::string &id ) const {
                ++*stats().lookup_calls;
                if ( ! unionTable ) return nullptr;
                ++*stats().map_lookups;
                auto it = unionTable->find( id );
                return it == unionTable->end() ? nullptr : it->second.decl;
        }

        TraitDecl *Indexer::lookupTrait( const std::string &id ) const {
                ++*stats().lookup_calls;
                if ( ! traitTable ) return nullptr;
                ++*stats().map_lookups;
                auto it = traitTable->find( id );
                return it == traitTable->end() ? nullptr : it->second.decl;
        }

        const Indexer* Indexer::atScope( unsigned long target ) const {
                // by lazy construction, final indexer in list has repScope 0, cannot be > target
                // otherwise, will find first scope representing the target
                const Indexer* indexer = this;
                while ( indexer->repScope > target ) {
                        indexer = indexer->prevScope.get();
                }
                return indexer;
        }

        NamedTypeDecl *Indexer::globalLookupType( const std::string &id ) const {
                return atScope( 0 )->lookupType( id );
        }

        StructDecl *Indexer::globalLookupStruct( const std::string &id ) const {
                return atScope( 0 )->lookupStruct( id );
        }

        UnionDecl *Indexer::globalLookupUnion( const std::string &id ) const {
                return atScope( 0 )->lookupUnion( id );
        }

        EnumDecl *Indexer::globalLookupEnum( const std::string &id ) const {
                return atScope( 0 )->lookupEnum( id );
        }

        bool isFunction( DeclarationWithType * decl ) {
                return GenPoly::getFunctionType( decl->get_type() );
        }

        bool isObject( DeclarationWithType * decl ) {
                return ! isFunction( decl );
        }

        bool isDefinition( DeclarationWithType * decl ) {
                if ( FunctionDecl * func = dynamic_cast< FunctionDecl * >( decl ) ) {
                        // a function is a definition if it has a body
                        return func->statements;
                } else {
                        // an object is a definition if it is not marked extern.
                        // both objects must be marked extern
                        return ! decl->get_storageClasses().is_extern;
                }
        }

        
        bool Indexer::addedIdConflicts( 
                        const Indexer::IdData & existing, DeclarationWithType *added, 
                        Indexer::OnConflict handleConflicts, BaseSyntaxNode * deleteStmt ) {
                // if we're giving the same name mangling to things of different types then there is 
                // something wrong
                assert( (isObject( added ) && isObject( existing.id ) )
                        || ( isFunction( added ) && isFunction( existing.id ) ) );

                if ( LinkageSpec::isOverridable( existing.id->linkage ) ) {
                        // new definition shadows the autogenerated one, even at the same scope
                        return false;
                } else if ( LinkageSpec::isMangled( added->linkage ) 
                                || ResolvExpr::typesCompatible( 
                                        added->get_type(), existing.id->get_type(), Indexer() ) ) {

                        // it is a conflict if one declaration is deleted and the other is not
                        if ( deleteStmt && ! existing.deleteStmt ) {
                                if ( handleConflicts.mode == OnConflict::Error ) {
                                        SemanticError( added, "deletion of defined identifier " );
                                }
                                return true;
                        } else if ( ! deleteStmt && existing.deleteStmt ) {
                                if ( handleConflicts.mode == OnConflict::Error ) {
                                        SemanticError( added, "definition of deleted identifier " );
                                }
                                return true;
                        }

                        if ( isDefinition( added ) && isDefinition( existing.id ) ) {
                                if ( handleConflicts.mode == OnConflict::Error ) {
                                        SemanticError( added, 
                                                isFunction( added ) ? 
                                                        "duplicate function definition for " : 
                                                        "duplicate object definition for " );
                                }
                                return true;
                        } // if
                } else {
                        if ( handleConflicts.mode == OnConflict::Error ) {
                                SemanticError( added, "duplicate definition for " );
                        }
                        return true;
                } // if

                return true;
        }

        bool Indexer::hasCompatibleCDecl( const std::string &id, const std::string &mangleName ) const {
                if ( ! idTable ) return false;

                ++*stats().map_lookups;
                auto decls = idTable->find( id );
                if ( decls == idTable->end() ) return false;

                for ( auto decl : *(decls->second) ) {
                        // skip other scopes (hidden by this decl)
                        if ( decl.second.scope != scope ) continue;
                        // check for C decl with compatible type (by mangleName)
                        if ( ! LinkageSpec::isMangled( decl.second.id->linkage ) && decl.first == mangleName ) {
                                return true;
                        }
                }
                
                return false;
        }

        bool Indexer::hasIncompatibleCDecl( 
                        const std::string &id, const std::string &mangleName ) const {
                if ( ! idTable ) return false;

                ++*stats().map_lookups;
                auto decls = idTable->find( id );
                if ( decls == idTable->end() ) return false;

                for ( auto decl : *(decls->second) ) {
                        // skip other scopes (hidden by this decl)
                        if ( decl.second.scope != scope ) continue;
                        // check for C decl with incompatible type (by manglename)
                        if ( ! LinkageSpec::isMangled( decl.second.id->linkage ) && decl.first != mangleName ) {
                                return true;
                        }
                }

                return false;
        }

        void Indexer::addId( 
                        DeclarationWithType *decl, OnConflict handleConflicts, Expression * baseExpr, 
                        BaseSyntaxNode * deleteStmt ) {
                ++*stats().add_calls;
                if ( decl->name == "" ) return;
                
                const std::string &name = decl->name;
                std::string mangleName;
                if ( LinkageSpec::isOverridable( decl->linkage ) ) {
                        // mangle the name without including the appropriate suffix, so overridable routines 
                        // are placed into the same "bucket" as their user defined versions.
                        mangleName = Mangler::mangle( decl, false );
                } else {
                        mangleName = Mangler::mangle( decl );
                } // if

                // this ensures that no two declarations with the same unmangled name at the same scope 
                // both have C linkage
                if ( LinkageSpec::isMangled( decl->linkage ) ) {
                        // Check that a Cforall declaration doesn't override any C declaration
                        if ( hasCompatibleCDecl( name, mangleName ) ) {
                                SemanticError( decl, "Cforall declaration hides C function " );
                        }
                } else {
                        // NOTE: only correct if name mangling is completely isomorphic to C 
                        // type-compatibility, which it may not be.
                        if ( hasIncompatibleCDecl( name, mangleName ) ) {
                                SemanticError( decl, "conflicting overload of C function " );
                        }
                }

                // ensure tables exist and add identifier
                MangleTable::Ptr mangleTable;
                if ( ! idTable ) {
                        idTable = IdTable::new_ptr();
                        mangleTable = MangleTable::new_ptr();
                } else {
                        ++*stats().map_lookups;
                        auto decls = idTable->find( name );
                        if ( decls == idTable->end() ) {
                                mangleTable = MangleTable::new_ptr();
                        } else {
                                mangleTable = decls->second;
                                // skip in-scope repeat declarations of same identifier
                                ++*stats().map_lookups;
                                auto existing = mangleTable->find( mangleName );
                                if ( existing != mangleTable->end()
                                                && existing->second.scope == scope
                                                && existing->second.id ) {
                                        if ( addedIdConflicts( existing->second, decl, handleConflicts, deleteStmt ) ) {
                                                if ( handleConflicts.mode == OnConflict::Delete ) {
                                                        // set delete expression for conflicting identifier
                                                        lazyInitScope();
                                                        *stats().map_mutations += 2;
                                                        idTable = idTable->set(
                                                                name,
                                                                mangleTable->set( 
                                                                        mangleName, 
                                                                        IdData{ existing->second, handleConflicts.deleteStmt } ) );
                                                }
                                                return;
                                        }
                                }
                        }
                }

                // add/overwrite with new identifier
                lazyInitScope();
                *stats().map_mutations += 2;
                idTable = idTable->set( 
                        name,
                        mangleTable->set( mangleName, IdData{ decl, baseExpr, deleteStmt, scope } ) );
        }

        void Indexer::addId( DeclarationWithType * decl, Expression * baseExpr ) {
                // default handling of conflicts is to raise an error
                addId( decl, OnConflict::error(), baseExpr, decl->isDeleted ? decl : nullptr );
        }

        void Indexer::addDeletedId( DeclarationWithType * decl, BaseSyntaxNode * deleteStmt ) {
                // default handling of conflicts is to raise an error
                addId( decl, OnConflict::error(), nullptr, deleteStmt );
        }

        bool addedTypeConflicts( NamedTypeDecl *existing, NamedTypeDecl *added ) {
                if ( existing->base == nullptr ) {
                        return false;
                } else if ( added->base == nullptr ) {
                        return true;
                } else {
                        assert( existing->base && added->base );
                        // typedef redeclarations are errors only if types are different
                        if ( ! ResolvExpr::typesCompatible( existing->base, added->base, Indexer() ) ) {
                                SemanticError( added->location, "redeclaration of " + added->name );
                        }
                }
                // does not need to be added to the table if both existing and added have a base that are 
                // the same
                return true;
        }

        void Indexer::addType( NamedTypeDecl *decl ) {
                ++*stats().add_calls;
                const std::string &id = decl->name;

                if ( ! typeTable ) { 
                        typeTable = TypeTable::new_ptr();
                } else {
                        ++*stats().map_lookups;
                        auto existing = typeTable->find( id );
                        if ( existing != typeTable->end() 
                                && existing->second.scope == scope 
                                && addedTypeConflicts( existing->second.decl, decl ) ) return;
                }
                
                lazyInitScope();
                ++*stats().map_mutations;
                typeTable = typeTable->set( id, Scoped<NamedTypeDecl>{ decl, scope } );
        }

        bool addedDeclConflicts( AggregateDecl *existing, AggregateDecl *added ) {
                if ( ! existing->body ) {
                        return false;
                } else if ( added->body ) {
                        SemanticError( added, "redeclaration of " );
                } // if
                return true;
        }

        void Indexer::addStruct( const std::string &id ) {
                addStruct( new StructDecl( id ) );
        }

        void Indexer::addStruct( StructDecl *decl ) {
                ++*stats().add_calls;
                const std::string &id = decl->name;

                if ( ! structTable ) {
                        structTable = StructTable::new_ptr();
                } else {
                        ++*stats().map_lookups;
                        auto existing = structTable->find( id );
                        if ( existing != structTable->end()  
                                && existing->second.scope == scope 
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++*stats().map_mutations;
                structTable = structTable->set( id, Scoped<StructDecl>{ decl, scope } );
        }

        void Indexer::addEnum( EnumDecl *decl ) {
                ++*stats().add_calls;
                const std::string &id = decl->name;

                if ( ! enumTable ) {
                        enumTable = EnumTable::new_ptr();
                } else {
                        ++*stats().map_lookups;
                        auto existing = enumTable->find( id );
                        if ( existing != enumTable->end()  
                                && existing->second.scope == scope 
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }
                
                lazyInitScope();
                ++*stats().map_mutations;
                enumTable = enumTable->set( id, Scoped<EnumDecl>{ decl, scope } );
        }

        void Indexer::addUnion( const std::string &id ) {
                addUnion( new UnionDecl( id ) );
        }

        void Indexer::addUnion( UnionDecl *decl ) {
                ++*stats().add_calls;
                const std::string &id = decl->name;

                if ( ! unionTable ) {
                        unionTable = UnionTable::new_ptr();
                } else {
                        ++*stats().map_lookups;
                        auto existing = unionTable->find( id );
                        if ( existing != unionTable->end() 
                                && existing->second.scope == scope 
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++*stats().map_mutations;
                unionTable = unionTable->set( id, Scoped<UnionDecl>{ decl, scope } );
        }

        void Indexer::addTrait( TraitDecl *decl ) {
                ++*stats().add_calls;
                const std::string &id = decl->name;

                if ( ! traitTable ) {
                        traitTable = TraitTable::new_ptr();
                } else {
                        ++*stats().map_lookups;
                        auto existing = traitTable->find( id );
                        if ( existing != traitTable->end() 
                                && existing->second.scope == scope 
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++*stats().map_mutations;
                traitTable = traitTable->set( id, Scoped<TraitDecl>{ decl, scope } );
        }

        void Indexer::addMembers( AggregateDecl * aggr, Expression * expr, 
                        OnConflict handleConflicts ) {
                for ( Declaration * decl : aggr->members ) {
                        if ( DeclarationWithType * dwt = dynamic_cast< DeclarationWithType * >( decl ) ) {
                                addId( dwt, handleConflicts, expr );
                                if ( dwt->name == "" ) {
                                        Type * t = dwt->get_type()->stripReferences();
                                        if ( dynamic_cast<StructInstType*>( t ) || dynamic_cast<UnionInstType*>( t ) ) {
                                                Expression * base = expr->clone();
                                                ResolvExpr::Cost cost = ResolvExpr::Cost::zero; // xxx - carry this cost into the indexer as a base cost?
                                                ResolvExpr::referenceToRvalueConversion( base, cost );
                                                addMembers( t->getAggr(), new MemberExpr( dwt, base ), handleConflicts );
                                        }
                                }
                        }
                }
        }

        void Indexer::addWith( std::list< Expression * > & withExprs, BaseSyntaxNode * withStmt ) {
                for ( Expression * expr : withExprs ) {
                        if ( expr->result ) {
                                AggregateDecl * aggr = expr->result->stripReferences()->getAggr();
                                assertf( aggr, "WithStmt expr has non-aggregate type: %s", toString( expr->result ).c_str() );

                                addMembers( aggr, expr, OnConflict::deleteWith( withStmt ) );
                        }
                }
        }

        void Indexer::addIds( const std::list< DeclarationWithType * > & decls ) {
                for ( auto d : decls ) {
                        addId( d );
                }
        }

        void Indexer::addTypes( const std::list< TypeDecl * > & tds ) {
                for ( auto td : tds ) {
                        addType( td );
                        addIds( td->assertions );
                }
        }

        void Indexer::addFunctionType( FunctionType * ftype ) {
                addTypes( ftype->forall );
                addIds( ftype->returnVals );
                addIds( ftype->parameters );
        }

        Expression * Indexer::IdData::combine( ResolvExpr::Cost & cost ) const {
                Expression * ret = nullptr;
                if ( baseExpr ) {
                        Expression * base = baseExpr->clone();
                        ResolvExpr::referenceToRvalueConversion( base, cost );
                        ret = new MemberExpr( id, base );
                        // xxx - this introduces hidden environments, for now remove them.
                        // std::swap( base->env, ret->env );
                        delete base->env;
                        base->env = nullptr;
                } else {
                        ret = new VariableExpr( id );
                }
                if ( deleteStmt ) ret = new DeletedExpr( ret, deleteStmt );
                return ret;
        }
} // namespace SymTab

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