Index: src/InitTweak/FixInitNew.cpp =================================================================== --- src/InitTweak/FixInitNew.cpp (revision 000d68fa1bff51eb40c559cdf944cdb21cfa48e2) +++ src/InitTweak/FixInitNew.cpp (revision 4852232d15fa17599c3034e16b477b4ef32051ed) @@ -42,204 +42,1310 @@ namespace InitTweak { + namespace { - // Shallow copy the pointer list for return. - std::vector> getGenericParams( const ast::Type * t ) { - if ( auto inst = dynamic_cast( t ) ) { - return inst->base->params; - } - if ( auto inst = dynamic_cast( t ) ) { - return inst->base->params; - } - return {}; - } - - /// Given type T, generate type of default ctor/dtor, i.e. function type void (*) (T &). - ast::FunctionDecl * genDefaultFunc( - const CodeLocation loc, - const std::string fname, - const ast::Type * paramType, - bool maybePolymorphic = true) { - std::vector> typeParams; - if ( maybePolymorphic ) typeParams = getGenericParams( paramType ); - auto dstParam = new ast::ObjectDecl( loc, - "_dst", - new ast::ReferenceType( paramType ), - nullptr, - {}, - ast::Linkage::Cforall +// Shallow copy the pointer list for return. +std::vector> getGenericParams( const ast::Type * t ) { + if ( auto inst = dynamic_cast( t ) ) { + return inst->base->params; + } + if ( auto inst = dynamic_cast( t ) ) { + return inst->base->params; + } + return {}; +} + +/// Given type T, generate type of default ctor/dtor, i.e. function type void (*) (T &). +ast::FunctionDecl * genDefaultFunc( + const CodeLocation loc, + const std::string fname, + const ast::Type * paramType, + bool maybePolymorphic = true) { + std::vector> typeParams; + if ( maybePolymorphic ) typeParams = getGenericParams( paramType ); + auto dstParam = new ast::ObjectDecl( loc, + "_dst", + new ast::ReferenceType( paramType ), + nullptr, + {}, + ast::Linkage::Cforall + ); + return new ast::FunctionDecl( loc, + fname, + std::move(typeParams), + {dstParam}, + {}, + new ast::CompoundStmt(loc), + {}, + ast::Linkage::Cforall + ); +} + +struct SelfAssignChecker { + void previsit( const ast::ApplicationExpr * appExpr ); +}; + +struct StmtExprResult { + const ast::StmtExpr * previsit( const ast::StmtExpr * stmtExpr ); +}; + +/// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which +/// function calls need their parameters to be copy constructed +struct InsertImplicitCalls : public ast::WithShortCircuiting { + const ast::Expr * postvisit( const ast::ApplicationExpr * appExpr ); + + // only handles each UniqueExpr once + // if order of visit does not change, this should be safe + void previsit (const ast::UniqueExpr *); + + std::unordered_set visitedIds; +}; + +/// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr, +/// generate/resolve copy construction expressions for each, and generate/resolve destructors for both +/// arguments and return value temporaries +struct ResolveCopyCtors final : public ast::WithGuards, public ast::WithStmtsToAdd<>, public ast::WithSymbolTable, public ast::WithShortCircuiting, public ast::WithVisitorRef, public ast::WithConstTranslationUnit { + const ast::Expr * postvisit( const ast::ImplicitCopyCtorExpr * impCpCtorExpr ); + const ast::StmtExpr * previsit( const ast::StmtExpr * stmtExpr ); + const ast::UniqueExpr * previsit( const ast::UniqueExpr * unqExpr ); + + /// handles distant mutations of environment manually. + /// WithConstTypeSubstitution cannot remember where the environment is from + + /// MUST be called at start of overload previsit + void previsit( const ast::Expr * expr); + /// MUST be called at return of overload postvisit + const ast::Expr * postvisit(const ast::Expr * expr); + + /// create and resolve ctor/dtor expression: fname(var, [cpArg]) + const ast::Expr * makeCtorDtor( const std::string & fname, const ast::ObjectDecl * var, const ast::Expr * cpArg = nullptr ); + /// true if type does not need to be copy constructed to ensure correctness + bool skipCopyConstruct( const ast::Type * type ); + ast::ptr< ast::Expr > copyConstructArg( const ast::Expr * arg, const ast::ImplicitCopyCtorExpr * impCpCtorExpr, const ast::Type * formal ); + ast::Expr * destructRet( const ast::ObjectDecl * ret, const ast::Expr * arg ); +private: + /// hack to implement WithTypeSubstitution while conforming to mutation safety. + ast::TypeSubstitution * env = nullptr; + bool envModified = false; +}; + +/// collects constructed object decls - used as a base class +struct ObjDeclCollector : public ast::WithGuards, public ast::WithShortCircuiting { + // use ordered data structure to maintain ordering for set_difference and for consistent error messages + typedef std::list< const ast::ObjectDecl * > ObjectSet; + void previsit( const ast::CompoundStmt *compoundStmt ); + void previsit( const ast::DeclStmt *stmt ); + + // don't go into other functions + void previsit( const ast::FunctionDecl * ) { visit_children = false; } + +protected: + ObjectSet curVars; +}; + +// debug +template +struct PrintSet { + PrintSet( const ObjectSet & objs ) : objs( objs ) {} + const ObjectSet & objs; +}; +template +PrintSet printSet( const ObjectSet & objs ) { return PrintSet( objs ); } +template +std::ostream & operator<<( std::ostream & out, const PrintSet & set) { + out << "{ "; + for ( auto & obj : set.objs ) { + out << obj->name << ", " ; + } // for + out << " }"; + return out; +} + +struct LabelFinder final : public ObjDeclCollector { + typedef std::map< std::string, ObjectSet > LabelMap; + // map of Label -> live variables at that label + LabelMap vars; + + typedef ObjDeclCollector Parent; + using Parent::previsit; + void previsit( const ast::Stmt * stmt ); + + void previsit( const ast::CompoundStmt *compoundStmt ); + void previsit( const ast::DeclStmt *stmt ); +}; + +/// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed +/// (currently by FixInit) +struct InsertDtors final : public ObjDeclCollector, public ast::WithStmtsToAdd<> { + typedef std::list< ObjectDecl * > OrderedDecls; + typedef std::list< OrderedDecls > OrderedDeclsStack; + + InsertDtors( ast::Pass & finder ) : finder( finder ), labelVars( finder.core.vars ) {} + + typedef ObjDeclCollector Parent; + using Parent::previsit; + + void previsit( const ast::FunctionDecl * funcDecl ); + + void previsit( const ast::BranchStmt * stmt ); +private: + void handleGoto( const ast::BranchStmt * stmt ); + + ast::Pass & finder; + LabelFinder::LabelMap & labelVars; + OrderedDeclsStack reverseDeclOrder; +}; + +/// expand each object declaration to use its constructor after it is declared. +struct FixInit : public ast::WithStmtsToAdd<> { + static void fixInitializers( ast::TranslationUnit &translationUnit ); + + const ast::DeclWithType * postvisit( const ast::ObjectDecl *objDecl ); + + std::list< ast::ptr< ast::Decl > > staticDtorDecls; +}; + +/// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors +/// for any member that is missing a corresponding ctor/dtor call. +/// error if a member is used before constructed +struct GenStructMemberCalls final : public ast::WithGuards, public ast::WithShortCircuiting, public ast::WithSymbolTable, public ast::WithVisitorRef, public ast::WithConstTranslationUnit { + void previsit( const ast::FunctionDecl * funcDecl ); + const ast::DeclWithType * postvisit( const ast::FunctionDecl * funcDecl ); + + void previsit( const ast::MemberExpr * memberExpr ); + void previsit( const ast::ApplicationExpr * appExpr ); + + /// Note: this post mutate used to be in a separate visitor. If this pass breaks, one place to examine is whether it is + /// okay for this part of the recursion to occur alongside the rest. + const ast::Expr * postvisit( const ast::UntypedExpr * expr ); + + SemanticErrorException errors; +private: + template< typename... Params > + void emit( CodeLocation, const Params &... params ); + + ast::FunctionDecl * function = nullptr; + std::set< const ast::DeclWithType * > unhandled; + std::map< const ast::DeclWithType *, CodeLocation > usedUninit; + const ast::ObjectDecl * thisParam = nullptr; + bool isCtor = false; // true if current function is a constructor + const ast::StructDecl * structDecl = nullptr; +}; + +/// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument +struct FixCtorExprs final : public ast::WithDeclsToAdd<>, public ast::WithSymbolTable, public ast::WithShortCircuiting, public ast::WithConstTranslationUnit { + const ast::Expr * postvisit( const ast::ConstructorExpr * ctorExpr ); +}; + +/// add CompoundStmts around top-level expressions so that temporaries are destroyed in the correct places. +struct SplitExpressions : public ast::WithShortCircuiting { + ast::Stmt * postvisit( const ast::ExprStmt * stmt ); + void previsit( const ast::TupleAssignExpr * expr ); +}; + +/// find and return the destructor used in `input`. If `input` is not a simple destructor call, generate a thunk +/// that wraps the destructor, insert it into `stmtsToAdd` and return the new function declaration +const ast::DeclWithType * getDtorFunc( const ast::ObjectDecl * objDecl, const ast::Stmt * input, std::list< ast::ptr > & stmtsToAdd ) { + const CodeLocation loc = input->location; + // unwrap implicit statement wrapper + // Statement * dtor = input; + assert( input ); + // std::list< const ast::Expr * > matches; + auto matches = collectCtorDtorCalls( input ); + + if ( dynamic_cast< const ast::ExprStmt * >( input ) ) { + // only one destructor call in the expression + if ( matches.size() == 1 ) { + auto func = getFunction( matches.front() ); + assertf( func, "getFunction failed to find function in %s", toString( matches.front() ).c_str() ); + + // cleanup argument must be a function, not an object (including function pointer) + if ( auto dtorFunc = dynamic_cast< const ast::FunctionDecl * > ( func ) ) { + if ( dtorFunc->type->forall.empty() ) { + // simple case where the destructor is a monomorphic function call - can simply + // use that function as the cleanup function. + return func; + } + } + } + } + + // otherwise the cleanup is more complicated - need to build a single argument cleanup function that + // wraps the more complicated code. + static UniqueName dtorNamer( "__cleanup_dtor" ); + std::string name = dtorNamer.newName(); + ast::FunctionDecl * dtorFunc = genDefaultFunc( loc, name, objDecl->type->stripReferences(), false ); + stmtsToAdd.push_back( new ast::DeclStmt(loc, dtorFunc ) ); + + // the original code contains uses of objDecl - replace them with the newly generated 'this' parameter. + const ast::ObjectDecl * thisParam = getParamThis( dtorFunc ); + const ast::Expr * replacement = new ast::VariableExpr( loc, thisParam ); + + auto base = replacement->result->stripReferences(); + if ( dynamic_cast< const ast::ArrayType * >( base ) || dynamic_cast< const ast::TupleType * > ( base ) ) { + // need to cast away reference for array types, since the destructor is generated without the reference type, + // and for tuple types since tuple indexing does not work directly on a reference + replacement = new ast::CastExpr( replacement, base ); + } + auto dtor = ast::DeclReplacer::replace( input, ast::DeclReplacer::ExprMap{ std::make_pair( objDecl, replacement ) } ); + auto mutStmts = dtorFunc->stmts.get_and_mutate(); + mutStmts->push_back(strict_dynamic_cast( dtor )); + dtorFunc->stmts = mutStmts; + + return dtorFunc; +} + +void FixInit::fixInitializers( ast::TranslationUnit & translationUnit ) { + ast::Pass fixer; + + // can't use mutateAll, because need to insert declarations at top-level + // can't use DeclMutator, because sometimes need to insert IfStmt, etc. + SemanticErrorException errors; + for ( auto i = translationUnit.decls.begin(); i != translationUnit.decls.end(); ++i ) { + try { + // maybeAccept( *i, fixer ); translationUnit should never contain null + *i = (*i)->accept(fixer); + translationUnit.decls.splice( i, fixer.core.staticDtorDecls ); + } catch( SemanticErrorException &e ) { + errors.append( e ); + } // try + } // for + if ( ! errors.isEmpty() ) { + throw errors; + } // if +} + +const ast::StmtExpr * StmtExprResult::previsit( const ast::StmtExpr * stmtExpr ) { + // we might loose the result expression here so add a pointer to trace back + assert( stmtExpr->result ); + const ast::Type * result = stmtExpr->result; + if ( ! result->isVoid() ) { + auto mutExpr = mutate(stmtExpr); + const ast::CompoundStmt * body = mutExpr->stmts; + assert( ! body->kids.empty() ); + mutExpr->resultExpr = body->kids.back().strict_as(); + return mutExpr; + } + return stmtExpr; +} + +ast::Stmt * SplitExpressions::postvisit( const ast::ExprStmt * stmt ) { + // wrap each top-level ExprStmt in a block so that destructors for argument and return temporaries are destroyed + // in the correct places + ast::CompoundStmt * ret = new ast::CompoundStmt( stmt->location, { stmt } ); + return ret; +} + +void SplitExpressions::previsit( const ast::TupleAssignExpr * ) { + // don't do this within TupleAssignExpr, since it is already broken up into multiple expressions + visit_children = false; +} + +// Relatively simple structural comparison for expressions, needed to determine +// if two expressions are "the same" (used to determine if self assignment occurs) +struct StructuralChecker { + // Strip all casts and then dynamic_cast. + template + static const T * cast( const ast::Expr * expr ) { + // this might be too permissive. It's possible that only particular casts are relevant. + while ( auto cast = dynamic_cast< const ast::CastExpr * >( expr ) ) { + expr = cast->arg; + } + return dynamic_cast< const T * >( expr ); + } + + void previsit( const ast::Expr * ) { + // anything else does not qualify + result = false; + } + + // ignore casts + void previsit( const ast::CastExpr * ) {} + + void previsit( const ast::MemberExpr * memExpr ) { + if ( auto otherMember = cast< ast::MemberExpr >( other ) ) { + if ( otherMember->member == memExpr->member ) { + other = otherMember->aggregate; + return; + } + } + result = false; + } + + void previsit( const ast::VariableExpr * varExpr ) { + if ( auto otherVar = cast< ast::VariableExpr >( other ) ) { + if ( otherVar->var == varExpr->var ) { + return; + } + } + result = false; + } + + void previsit( const ast::AddressExpr * ) { + if ( auto addrExpr = cast< ast::AddressExpr >( other ) ) { + other = addrExpr->arg; + return; + } + result = false; + } + + const ast::Expr * other; + bool result = true; + StructuralChecker( const ast::Expr * other ) : other(other) {} +}; + +bool structurallySimilar( const ast::Expr * e1, const ast::Expr * e2 ) { + return ast::Pass::read( e1, e2 ); +} + +void SelfAssignChecker::previsit( const ast::ApplicationExpr * appExpr ) { + auto function = getFunction( appExpr ); + // Doesn't use isAssignment, because ?+=?, etc. should not count as self-assignment. + if ( function->name == "?=?" && appExpr->args.size() == 2 + // Check for structural similarity (same variable use, ignore casts, etc. + // (but does not look too deeply, anything looking like a function is off limits). + && structurallySimilar( appExpr->args.front(), appExpr->args.back() ) ) { + SemanticWarning( appExpr->location, Warning::SelfAssignment, toCString( appExpr->args.front() ) ); + } +} + +const ast::Expr * InsertImplicitCalls::postvisit( const ast::ApplicationExpr * appExpr ) { + if ( auto function = appExpr->func.as() ) { + if ( function->var->linkage.is_builtin ) { + // optimization: don't need to copy construct in order to call intrinsic functions + return appExpr; + } else if ( auto funcDecl = function->var.as() ) { + auto ftype = dynamic_cast< const ast::FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) ); + assertf( ftype, "Function call without function type: %s", toString( funcDecl ).c_str() ); + if ( CodeGen::isConstructor( funcDecl->name ) && ftype->params.size() == 2 ) { + auto t1 = getPointerBase( ftype->params.front() ); + auto t2 = ftype->params.back(); + assert( t1 ); + + if ( ResolvExpr::typesCompatible( t1, t2 ) ) { + // optimization: don't need to copy construct in order to call a copy constructor + return appExpr; + } // if + } else if ( CodeGen::isDestructor( funcDecl->name ) ) { + // correctness: never copy construct arguments to a destructor + return appExpr; + } // if + } // if + } // if + CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; ) + + // wrap each function call so that it is easy to identify nodes that have to be copy constructed + ast::ptr tmp = appExpr->env; + auto mutExpr = mutate(appExpr); + mutExpr->env = nullptr; + + auto expr = new ast::ImplicitCopyCtorExpr( appExpr->location, mutExpr ); + // Move the type substitution to the new top-level. The substitution + // is needed to obtain the type of temporary variables so that copy + // constructor calls can be resolved. + expr->env = tmp; + return expr; +} + +void ResolveCopyCtors::previsit(const ast::Expr * expr) { + if ( nullptr == expr->env ) { + return; + } + GuardValue( env ) = expr->env->clone(); + GuardValue( envModified ) = false; +} + +const ast::Expr * ResolveCopyCtors::postvisit(const ast::Expr * expr) { + // No local environment, skip. + if ( nullptr == expr->env ) { + return expr; + // Environment was modified, mutate and replace. + } else if ( envModified ) { + auto mutExpr = mutate(expr); + mutExpr->env = env; + return mutExpr; + // Environment was not mutated, delete the shallow copy before guard. + } else { + delete env; + return expr; + } +} + +bool ResolveCopyCtors::skipCopyConstruct( const ast::Type * type ) { return ! isConstructable( type ); } + +const ast::Expr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, const ast::ObjectDecl * var, const ast::Expr * cpArg ) { + assert( var ); + assert( var->isManaged() ); + assert( !cpArg || cpArg->isManaged() ); + // arrays are not copy constructed, so this should always be an ExprStmt + ast::ptr< ast::Stmt > stmt = genCtorDtor(var->location, fname, var, cpArg ); + assertf( stmt, "ResolveCopyCtors: genCtorDtor returned nullptr: %s / %s / %s", fname.c_str(), toString( var ).c_str(), toString( cpArg ).c_str() ); + auto exprStmt = stmt.strict_as()->callStmt.strict_as(); + ast::ptr untyped = exprStmt->expr; // take ownership of expr + + // resolve copy constructor + // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed + // (VariableExpr and already resolved expression) + CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; ) + ast::ptr resolved = ResolvExpr::findVoidExpression(untyped, { symtab, transUnit().global } ); + assert( resolved ); + if ( resolved->env ) { + // Extract useful information and discard new environments. Keeping them causes problems in PolyMutator passes. + env->add( *resolved->env ); + envModified = true; + auto mut = mutate(resolved.get()); + assertf(mut == resolved.get(), "newly resolved expression must be unique"); + mut->env = nullptr; + } // if + if ( auto assign = resolved.as() ) { + // fix newly generated StmtExpr + previsit( assign->stmtExpr ); + } + return resolved.release(); +} + +ast::ptr ResolveCopyCtors::copyConstructArg( + const ast::Expr * arg, const ast::ImplicitCopyCtorExpr * impCpCtorExpr, const ast::Type * formal ) +{ + static UniqueName tempNamer("_tmp_cp"); + const CodeLocation loc = impCpCtorExpr->location; + // CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *env << std::endl; ) + assert( arg->result ); + ast::ptr result = arg->result; + if ( skipCopyConstruct( result ) ) return arg; // skip certain non-copyable types + + // type may involve type variables, so apply type substitution to get temporary variable's actual type, + // since result type may not be substituted (e.g., if the type does not appear in the parameter list) + // Use applyFree so that types bound in function pointers are not substituted, e.g. in forall(dtype T) void (*)(T). + + // xxx - this originally mutates arg->result in place. is it correct? + assert( env ); + result = env->applyFree( result.get() ).node; + auto mutResult = result.get_and_mutate(); + mutResult->set_const(false); + + auto mutArg = mutate(arg); + mutArg->result = mutResult; + + ast::ptr guard = mutArg; + + ast::ptr tmp = new ast::ObjectDecl(loc, "__tmp", mutResult, nullptr ); + + // create and resolve copy constructor + CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; ) + auto cpCtor = makeCtorDtor( "?{}", tmp, mutArg ); + + if ( auto appExpr = dynamic_cast< const ast::ApplicationExpr * >( cpCtor ) ) { + // if the chosen constructor is intrinsic, the copy is unnecessary, so + // don't create the temporary and don't call the copy constructor + auto function = appExpr->func.strict_as(); + if ( function->var->linkage == ast::Linkage::Intrinsic ) { + // arguments that need to be boxed need a temporary regardless of whether the copy constructor is intrinsic, + // so that the object isn't changed inside of the polymorphic function + if ( ! GenPoly::needsBoxing( formal, result, impCpCtorExpr->callExpr, env ) ) { + // xxx - should arg->result be mutated? see comment above. + return guard; + } + } + } + + // set a unique name for the temporary once it's certain the call is necessary + auto mut = tmp.get_and_mutate(); + assertf (mut == tmp, "newly created ObjectDecl must be unique"); + mut->name = tempNamer.newName(); + + // replace argument to function call with temporary + stmtsToAddBefore.push_back( new ast::DeclStmt(loc, tmp ) ); + arg = cpCtor; + return destructRet( tmp, arg ); + + // impCpCtorExpr->dtors.push_front( makeCtorDtor( "^?{}", tmp ) ); +} + +ast::Expr * ResolveCopyCtors::destructRet( const ast::ObjectDecl * ret, const ast::Expr * arg ) { + auto global = transUnit().global; + // TODO: refactor code for generating cleanup attribute, since it's common and reused in ~3-4 places + // check for existing cleanup attribute before adding another(?) + // need to add __Destructor for _tmp_cp variables as well + + assertf( global.dtorStruct, "Destructor generation requires __Destructor definition." ); + assertf( global.dtorStruct->members.size() == 2, "__Destructor definition does not have expected fields." ); + assertf( global.dtorDestroy, "Destructor generation requires __destroy_Destructor." ); + + const CodeLocation loc = ret->location; + + // generate a __Destructor for ret that calls the destructor + auto res = makeCtorDtor( "^?{}", ret ); + auto dtor = mutate(res); + + // if the chosen destructor is intrinsic, elide the generated dtor handler + if ( arg && isIntrinsicCallExpr( dtor ) ) { + return new ast::CommaExpr(loc, arg, new ast::VariableExpr(loc, ret ) ); + } + + if ( ! dtor->env ) dtor->env = maybeClone( env ); + auto dtorFunc = getDtorFunc( ret, new ast::ExprStmt(loc, dtor ), stmtsToAddBefore ); + + auto dtorStructType = new ast::StructInstType( global.dtorStruct ); + + // what does this do??? + dtorStructType->params.push_back( new ast::TypeExpr(loc, new ast::VoidType() ) ); + + // cast destructor pointer to void (*)(void *), to silence GCC incompatible pointer warnings + auto dtorFtype = new ast::FunctionType(); + dtorFtype->params.push_back( new ast::PointerType(new ast::VoidType( ) ) ); + auto dtorType = new ast::PointerType( dtorFtype ); + + static UniqueName namer( "_ret_dtor" ); + auto retDtor = new ast::ObjectDecl(loc, namer.newName(), dtorStructType, new ast::ListInit(loc, { new ast::SingleInit(loc, ast::ConstantExpr::null(loc) ), new ast::SingleInit(loc, new ast::CastExpr( new ast::VariableExpr(loc, dtorFunc ), dtorType ) ) } ) ); + retDtor->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr(loc, global.dtorDestroy ) } ) ); + stmtsToAddBefore.push_back( new ast::DeclStmt(loc, retDtor ) ); + + if ( arg ) { + auto member = new ast::MemberExpr(loc, global.dtorStruct->members.front().strict_as(), new ast::VariableExpr(loc, retDtor ) ); + auto object = new ast::CastExpr( new ast::AddressExpr( new ast::VariableExpr(loc, ret ) ), new ast::PointerType(new ast::VoidType() ) ); + ast::Expr * assign = createBitwiseAssignment( member, object ); + return new ast::CommaExpr(loc, new ast::CommaExpr(loc, arg, assign ), new ast::VariableExpr(loc, ret ) ); + } + return nullptr; + // impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) ); +} + +const ast::Expr * ResolveCopyCtors::postvisit( const ast::ImplicitCopyCtorExpr *impCpCtorExpr ) { + CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; ) + + ast::ApplicationExpr * appExpr = mutate(impCpCtorExpr->callExpr.get()); + const ast::ObjectDecl * returnDecl = nullptr; + const CodeLocation loc = appExpr->location; + + // take each argument and attempt to copy construct it. + auto ftype = GenPoly::getFunctionType( appExpr->func->result ); + assert( ftype ); + auto & params = ftype->params; + auto iter = params.begin(); + for ( auto & arg : appExpr->args ) { + const ast::Type * formal = nullptr; + if ( iter != params.end() ) { // does not copy construct C-style variadic arguments + // DeclarationWithType * param = *iter++; + formal = *iter++; + } + + arg = copyConstructArg( arg, impCpCtorExpr, formal ); + } // for + + // each return value from the call needs to be connected with an ObjectDecl at the call site, which is + // initialized with the return value and is destructed later + // xxx - handle named return values? + const ast::Type * result = appExpr->result; + if ( ! result->isVoid() ) { + static UniqueName retNamer("_tmp_cp_ret"); + auto subResult = env->apply( result ).node; + auto ret = new ast::ObjectDecl(loc, retNamer.newName(), subResult, nullptr ); + auto mutType = mutate(ret->type.get()); + mutType->set_const( false ); + ret->type = mutType; + returnDecl = ret; + stmtsToAddBefore.push_back( new ast::DeclStmt(loc, ret ) ); + CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; ) + } // for + CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; ) + // ------------------------------------------------------ + + CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; ) + + // detach fields from wrapper node so that it can be deleted without deleting too much + + // xxx - actual env might be somewhere else, need to keep invariant + + // deletion of wrapper should be handled by pass template now + + // impCpCtorExpr->callExpr = nullptr; + assert (appExpr->env == nullptr); + appExpr->env = impCpCtorExpr->env; + // std::swap( impCpCtorExpr->env, appExpr->env ); + // assert( impCpCtorExpr->env == nullptr ); + // delete impCpCtorExpr; + + if ( returnDecl ) { + ast::Expr * assign = createBitwiseAssignment( new ast::VariableExpr(loc, returnDecl ), appExpr ); + if ( ! dynamic_cast< const ast::ReferenceType * >( result ) ) { + // destructing reference returns is bad because it can cause multiple destructor calls to the same object - the returned object is not a temporary + assign = destructRet( returnDecl, assign ); + assert(assign); + } else { + assign = new ast::CommaExpr(loc, assign, new ast::VariableExpr(loc, returnDecl ) ); + } + // move env from appExpr to retExpr + // std::swap( assign->env, appExpr->env ); + assign->env = appExpr->env; + // actual env is handled by common routine that replaces WithTypeSubstitution + return postvisit((const ast::Expr *)assign); + } else { + return postvisit((const ast::Expr *)appExpr); + } // if +} + +const ast::StmtExpr * ResolveCopyCtors::previsit( const ast::StmtExpr * _stmtExpr ) { + // function call temporaries should be placed at statement-level, rather than nested inside of a new statement expression, + // since temporaries can be shared across sub-expressions, e.g. + // [A, A] f(); // decl + // g([A] x, [A] y); // decl + // g(f()); // call + // f is executed once, so the return temporary is shared across the tuple constructors for x and y. + // Explicitly mutating children instead of mutating the inner compound statement forces the temporaries to be added + // to the outer context, rather than inside of the statement expression. + + // call the common routine that replaces WithTypeSubstitution + previsit((const ast::Expr *) _stmtExpr); + + visit_children = false; + const CodeLocation loc = _stmtExpr->location; + + assert( env ); + + symtab.enterScope(); + // visit all statements + auto stmtExpr = mutate(_stmtExpr); + auto mutStmts = mutate(stmtExpr->stmts.get()); + + auto & stmts = mutStmts->kids; + for ( auto & stmt : stmts ) { + stmt = stmt->accept( *visitor ); + } // for + stmtExpr->stmts = mutStmts; + symtab.leaveScope(); + + assert( stmtExpr->result ); + // const ast::Type * result = stmtExpr->result; + if ( ! stmtExpr->result->isVoid() ) { + static UniqueName retNamer("_tmp_stmtexpr_ret"); + + // result = result->clone(); + auto result = env->apply( stmtExpr->result.get() ).node; + if ( ! InitTweak::isConstructable( result ) ) { + // delete result; + return stmtExpr; + } + auto mutResult = result.get_and_mutate(); + mutResult->set_const(false); + + // create variable that will hold the result of the stmt expr + auto ret = new ast::ObjectDecl(loc, retNamer.newName(), mutResult, nullptr ); + stmtsToAddBefore.push_back( new ast::DeclStmt(loc, ret ) ); + + assertf( + stmtExpr->resultExpr, + "Statement-Expression should have a resulting expression at %s:%d", + stmtExpr->location.filename.c_str(), + stmtExpr->location.first_line ); - return new ast::FunctionDecl( loc, - fname, - std::move(typeParams), - {dstParam}, - {}, - new ast::CompoundStmt(loc), - {}, - ast::Linkage::Cforall - ); - } - - struct SelfAssignChecker { - void previsit( const ast::ApplicationExpr * appExpr ); - }; - - struct StmtExprResult { - const ast::StmtExpr * previsit( const ast::StmtExpr * stmtExpr ); - }; - - /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which - /// function calls need their parameters to be copy constructed - struct InsertImplicitCalls : public ast::WithShortCircuiting { - const ast::Expr * postvisit( const ast::ApplicationExpr * appExpr ); - - // only handles each UniqueExpr once - // if order of visit does not change, this should be safe - void previsit (const ast::UniqueExpr *); - - std::unordered_set visitedIds; - }; - - /// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr, - /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both - /// arguments and return value temporaries - struct ResolveCopyCtors final : public ast::WithGuards, public ast::WithStmtsToAdd<>, public ast::WithSymbolTable, public ast::WithShortCircuiting, public ast::WithVisitorRef, public ast::WithConstTranslationUnit { - const ast::Expr * postvisit( const ast::ImplicitCopyCtorExpr * impCpCtorExpr ); - const ast::StmtExpr * previsit( const ast::StmtExpr * stmtExpr ); - const ast::UniqueExpr * previsit( const ast::UniqueExpr * unqExpr ); - - /// handles distant mutations of environment manually. - /// WithConstTypeSubstitution cannot remember where the environment is from - - /// MUST be called at start of overload previsit - void previsit( const ast::Expr * expr); - /// MUST be called at return of overload postvisit - const ast::Expr * postvisit(const ast::Expr * expr); - - /// create and resolve ctor/dtor expression: fname(var, [cpArg]) - const ast::Expr * makeCtorDtor( const std::string & fname, const ast::ObjectDecl * var, const ast::Expr * cpArg = nullptr ); - /// true if type does not need to be copy constructed to ensure correctness - bool skipCopyConstruct( const ast::Type * type ); - ast::ptr< ast::Expr > copyConstructArg( const ast::Expr * arg, const ast::ImplicitCopyCtorExpr * impCpCtorExpr, const ast::Type * formal ); - ast::Expr * destructRet( const ast::ObjectDecl * ret, const ast::Expr * arg ); - private: - /// hack to implement WithTypeSubstitution while conforming to mutation safety. - ast::TypeSubstitution * env = nullptr; - bool envModified = false; - }; - - /// collects constructed object decls - used as a base class - struct ObjDeclCollector : public ast::WithGuards, public ast::WithShortCircuiting { - // use ordered data structure to maintain ordering for set_difference and for consistent error messages - typedef std::list< const ast::ObjectDecl * > ObjectSet; - void previsit( const ast::CompoundStmt *compoundStmt ); - void previsit( const ast::DeclStmt *stmt ); - - // don't go into other functions - void previsit( const ast::FunctionDecl * ) { visit_children = false; } - - protected: - ObjectSet curVars; - }; - - // debug - template - struct PrintSet { - PrintSet( const ObjectSet & objs ) : objs( objs ) {} - const ObjectSet & objs; - }; - template - PrintSet printSet( const ObjectSet & objs ) { return PrintSet( objs ); } - template - std::ostream & operator<<( std::ostream & out, const PrintSet & set) { - out << "{ "; - for ( auto & obj : set.objs ) { - out << obj->name << ", " ; - } // for - out << " }"; - return out; - } - - struct LabelFinder final : public ObjDeclCollector { - typedef std::map< std::string, ObjectSet > LabelMap; - // map of Label -> live variables at that label - LabelMap vars; - - typedef ObjDeclCollector Parent; - using Parent::previsit; - void previsit( const ast::Stmt * stmt ); - - void previsit( const ast::CompoundStmt *compoundStmt ); - void previsit( const ast::DeclStmt *stmt ); - }; - - /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed - /// (currently by FixInit) - struct InsertDtors final : public ObjDeclCollector, public ast::WithStmtsToAdd<> { - typedef std::list< ObjectDecl * > OrderedDecls; - typedef std::list< OrderedDecls > OrderedDeclsStack; - - InsertDtors( ast::Pass & finder ) : finder( finder ), labelVars( finder.core.vars ) {} - - typedef ObjDeclCollector Parent; - using Parent::previsit; - - void previsit( const ast::FunctionDecl * funcDecl ); - - void previsit( const ast::BranchStmt * stmt ); - private: - void handleGoto( const ast::BranchStmt * stmt ); - - ast::Pass & finder; - LabelFinder::LabelMap & labelVars; - OrderedDeclsStack reverseDeclOrder; - }; - - /// expand each object declaration to use its constructor after it is declared. - struct FixInit : public ast::WithStmtsToAdd<> { - static void fixInitializers( ast::TranslationUnit &translationUnit ); - - const ast::DeclWithType * postvisit( const ast::ObjectDecl *objDecl ); - - std::list< ast::ptr< ast::Decl > > staticDtorDecls; - }; - - /// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors - /// for any member that is missing a corresponding ctor/dtor call. - /// error if a member is used before constructed - struct GenStructMemberCalls final : public ast::WithGuards, public ast::WithShortCircuiting, public ast::WithSymbolTable, public ast::WithVisitorRef, public ast::WithConstTranslationUnit { - void previsit( const ast::FunctionDecl * funcDecl ); - const ast::DeclWithType * postvisit( const ast::FunctionDecl * funcDecl ); - - void previsit( const ast::MemberExpr * memberExpr ); - void previsit( const ast::ApplicationExpr * appExpr ); - - /// Note: this post mutate used to be in a separate visitor. If this pass breaks, one place to examine is whether it is - /// okay for this part of the recursion to occur alongside the rest. - const ast::Expr * postvisit( const ast::UntypedExpr * expr ); - - SemanticErrorException errors; - private: - template< typename... Params > - void emit( CodeLocation, const Params &... params ); - - ast::FunctionDecl * function = nullptr; - std::set< const ast::DeclWithType * > unhandled; - std::map< const ast::DeclWithType *, CodeLocation > usedUninit; - const ast::ObjectDecl * thisParam = nullptr; - bool isCtor = false; // true if current function is a constructor - const ast::StructDecl * structDecl = nullptr; - }; - - /// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument - struct FixCtorExprs final : public ast::WithDeclsToAdd<>, public ast::WithSymbolTable, public ast::WithShortCircuiting, public ast::WithConstTranslationUnit { - const ast::Expr * postvisit( const ast::ConstructorExpr * ctorExpr ); - }; - - /// add CompoundStmts around top-level expressions so that temporaries are destroyed in the correct places. - struct SplitExpressions : public ast::WithShortCircuiting { - ast::Stmt * postvisit( const ast::ExprStmt * stmt ); - void previsit( const ast::TupleAssignExpr * expr ); - }; + + const ast::ExprStmt * last = stmtExpr->resultExpr; + // xxx - if this is non-unique, need to copy while making resultExpr ref + assertf(last->unique(), "attempt to modify weakly shared statement"); + auto mutLast = mutate(last); + // above assertion means in-place mutation is OK + try { + mutLast->expr = makeCtorDtor( "?{}", ret, mutLast->expr ); + } catch(...) { + std::cerr << "*CFA internal error: "; + std::cerr << "can't resolve implicit constructor"; + std::cerr << " at " << stmtExpr->location.filename; + std::cerr << ":" << stmtExpr->location.first_line << std::endl; + + abort(); + } + + // add destructors after current statement + stmtsToAddAfter.push_back( new ast::ExprStmt(loc, makeCtorDtor( "^?{}", ret ) ) ); + + // must have a non-empty body, otherwise it wouldn't have a result + assert( ! stmts.empty() ); + + // if there is a return decl, add a use as the last statement; will not have return decl on non-constructable returns + stmts.push_back( new ast::ExprStmt(loc, new ast::VariableExpr(loc, ret ) ) ); + } // if + + assert( stmtExpr->returnDecls.empty() ); + assert( stmtExpr->dtors.empty() ); + + return stmtExpr; +} + +// to prevent warnings ('_unq0' may be used uninitialized in this function), +// insert an appropriate zero initializer for UniqueExpr temporaries. +ast::Init * makeInit( const ast::Type * t, CodeLocation const & loc ) { + if ( auto inst = dynamic_cast< const ast::StructInstType * >( t ) ) { + // initizer for empty struct must be empty + if ( inst->base->members.empty() ) { + return new ast::ListInit( loc, {} ); + } + } else if ( auto inst = dynamic_cast< const ast::UnionInstType * >( t ) ) { + // initizer for empty union must be empty + if ( inst->base->members.empty() ) { + return new ast::ListInit( loc, {} ); + } + } + + return new ast::ListInit( loc, { + new ast::SingleInit( loc, ast::ConstantExpr::from_int( loc, 0 ) ) + } ); +} + +const ast::UniqueExpr * ResolveCopyCtors::previsit( const ast::UniqueExpr * unqExpr ) { + visit_children = false; + // xxx - hack to prevent double-handling of unique exprs, otherwise too many temporary variables and destructors are generated + static std::unordered_map< int, const ast::UniqueExpr * > unqMap; + auto mutExpr = mutate(unqExpr); + if ( ! unqMap.count( unqExpr->id ) ) { + // resolve expr and find its + + auto impCpCtorExpr = mutExpr->expr.as(); + // PassVisitor fixer; + + mutExpr->expr = mutExpr->expr->accept( *visitor ); + // it should never be necessary to wrap a void-returning expression in a UniqueExpr - if this assumption changes, this needs to be rethought + assert( unqExpr->result ); + if ( impCpCtorExpr ) { + auto comma = unqExpr->expr.strict_as(); + auto var = comma->arg2.strict_as(); + // note the variable used as the result from the call + mutExpr->var = var; + } else { + // expr isn't a call expr, so create a new temporary variable to use to hold the value of the unique expression + mutExpr->object = new ast::ObjectDecl( mutExpr->location, toString("_unq", mutExpr->id), mutExpr->result, makeInit( mutExpr->result, mutExpr->location ) ); + mutExpr->var = new ast::VariableExpr( mutExpr->location, mutExpr->object ); + } + + unqMap[mutExpr->id] = mutExpr; + } else { + // take data from other UniqueExpr to ensure consistency + // delete unqExpr->get_expr(); + mutExpr->expr = unqMap[mutExpr->id]->expr; + // delete unqExpr->result; + mutExpr->result = mutExpr->expr->result; + } + return mutExpr; +} + +const ast::DeclWithType * FixInit::postvisit( const ast::ObjectDecl *_objDecl ) { + const CodeLocation loc = _objDecl->location; + + // since this removes the init field from objDecl, it must occur after children are mutated (i.e. postvisit) + if ( ast::ptr ctorInit = _objDecl->init.as() ) { + auto objDecl = mutate(_objDecl); + + // could this be non-unique? + if (objDecl != _objDecl) { + std::cerr << "FixInit: non-unique object decl " << objDecl->location << objDecl->name << std::endl; + } + // a decision should have been made by the resolver, so ctor and init are not both non-NULL + assert( ! ctorInit->ctor || ! ctorInit->init ); + if ( const ast::Stmt * ctor = ctorInit->ctor ) { + if ( objDecl->storage.is_static ) { + addDataSectionAttribute(objDecl); + // originally wanted to take advantage of gcc nested functions, but + // we get memory errors with this approach. To remedy this, the static + // variable is hoisted when the destructor needs to be called. + // + // generate: + // static T __objName_static_varN; + // void __objName_dtor_atexitN() { + // __dtor__...; + // } + // int f(...) { + // ... + // static bool __objName_uninitialized = true; + // if (__objName_uninitialized) { + // __ctor(__objName); + // __objName_uninitialized = false; + // atexit(__objName_dtor_atexitN); + // } + // ... + // } + + static UniqueName dtorCallerNamer( "_dtor_atexit" ); + + // static bool __objName_uninitialized = true + auto boolType = new ast::BasicType( ast::BasicType::Kind::Bool ); + auto boolInitExpr = new ast::SingleInit(loc, ast::ConstantExpr::from_int(loc, 1 ) ); + auto isUninitializedVar = new ast::ObjectDecl(loc, objDecl->mangleName + "_uninitialized", boolType, boolInitExpr, ast::Storage::Static, ast::Linkage::Cforall); + isUninitializedVar->fixUniqueId(); + + // __objName_uninitialized = false; + auto setTrue = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "?=?" ) ); + setTrue->args.push_back( new ast::VariableExpr(loc, isUninitializedVar ) ); + setTrue->args.push_back( ast::ConstantExpr::from_int(loc, 0 ) ); + + // generate body of if + auto initStmts = new ast::CompoundStmt(loc); + auto & body = initStmts->kids; + body.push_back( ctor ); + body.push_back( new ast::ExprStmt(loc, setTrue ) ); + + // put it all together + auto ifStmt = new ast::IfStmt(loc, new ast::VariableExpr(loc, isUninitializedVar ), initStmts, 0 ); + stmtsToAddAfter.push_back( new ast::DeclStmt(loc, isUninitializedVar ) ); + stmtsToAddAfter.push_back( ifStmt ); + + const ast::Stmt * dtor = ctorInit->dtor; + + // these should be automatically managed once reassigned + // objDecl->set_init( nullptr ); + // ctorInit->set_ctor( nullptr ); + // ctorInit->set_dtor( nullptr ); + if ( dtor ) { + // if the object has a non-trivial destructor, have to + // hoist it and the object into the global space and + // call the destructor function with atexit. + + // Statement * dtorStmt = dtor->clone(); + + // void __objName_dtor_atexitN(...) {...} + ast::FunctionDecl * dtorCaller = new ast::FunctionDecl(loc, objDecl->mangleName + dtorCallerNamer.newName(), {}, {}, {}, new ast::CompoundStmt(loc, {dtor}), ast::Storage::Static, ast::Linkage::C ); + dtorCaller->fixUniqueId(); + // dtorCaller->stmts->push_back( dtor ); + + // atexit(dtor_atexit); + auto callAtexit = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "atexit" ) ); + callAtexit->args.push_back( new ast::VariableExpr(loc, dtorCaller ) ); + + body.push_back( new ast::ExprStmt(loc, callAtexit ) ); + + // hoist variable and dtor caller decls to list of decls that will be added into global scope + staticDtorDecls.push_back( objDecl ); + staticDtorDecls.push_back( dtorCaller ); + + // need to rename object uniquely since it now appears + // at global scope and there could be multiple function-scoped + // static variables with the same name in different functions. + // Note: it isn't sufficient to modify only the mangleName, because + // then subsequent Indexer passes can choke on seeing the object's name + // if another object has the same name and type. An unfortunate side-effect + // of renaming the object is that subsequent NameExprs may fail to resolve, + // but there shouldn't be any remaining past this point. + static UniqueName staticNamer( "_static_var" ); + objDecl->name = objDecl->name + staticNamer.newName(); + objDecl->mangleName = Mangle::mangle( objDecl ); + objDecl->init = nullptr; + + // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope + // create a new object which is never used + static UniqueName dummyNamer( "_dummy" ); + auto dummy = new ast::ObjectDecl(loc, dummyNamer.newName(), new ast::PointerType(new ast::VoidType()), nullptr, ast::Storage::Static, ast::Linkage::Cforall, 0, { new ast::Attribute("unused") } ); + // delete ctorInit; + return dummy; + } else { + objDecl->init = nullptr; + return objDecl; + } + } else { + auto implicit = strict_dynamic_cast< const ast::ImplicitCtorDtorStmt * > ( ctor ); + auto ctorStmt = implicit->callStmt.as(); + const ast::ApplicationExpr * ctorCall = nullptr; + if ( ctorStmt && (ctorCall = isIntrinsicCallExpr( ctorStmt->expr )) && ctorCall->args.size() == 2 ) { + // clean up intrinsic copy constructor calls by making them into SingleInits + const ast::Expr * ctorArg = ctorCall->args.back(); + // ctorCall should be gone afterwards + auto mutArg = mutate(ctorArg); + mutArg->env = ctorCall->env; + // std::swap( ctorArg->env, ctorCall->env ); + objDecl->init = new ast::SingleInit(loc, mutArg ); + + // ctorCall->args.pop_back(); + } else { + stmtsToAddAfter.push_back( ctor ); + objDecl->init = nullptr; + // ctorInit->ctor = nullptr; + } + + const ast::Stmt * dtor = ctorInit->dtor; + if ( dtor ) { + auto implicit = strict_dynamic_cast< const ast::ImplicitCtorDtorStmt * >( dtor ); + const ast::Stmt * dtorStmt = implicit->callStmt; + + // don't need to call intrinsic dtor, because it does nothing, but + // non-intrinsic dtors must be called + if ( ! isIntrinsicSingleArgCallStmt( dtorStmt ) ) { + // set dtor location to the object's location for error messages + auto dtorFunc = getDtorFunc( objDecl, dtorStmt, stmtsToAddBefore ); + objDecl->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr(loc, dtorFunc ) } ) ); + // ctorInit->dtor = nullptr; + } // if + } + } // if + } else if ( const ast::Init * init = ctorInit->init ) { + objDecl->init = init; + // ctorInit->init = nullptr; + } else { + // no constructor and no initializer, which is okay + objDecl->init = nullptr; + } // if + // delete ctorInit; + return objDecl; + } // if + return _objDecl; +} + +void ObjDeclCollector::previsit( const ast::CompoundStmt * ) { + GuardValue( curVars ); +} + +void ObjDeclCollector::previsit( const ast::DeclStmt * stmt ) { + // keep track of all variables currently in scope + if ( auto objDecl = stmt->decl.as() ) { + curVars.push_back( objDecl ); + } // if +} + +void LabelFinder::previsit( const ast::Stmt * stmt ) { + // for each label, remember the variables in scope at that label. + for ( auto l : stmt->labels ) { + vars[l] = curVars; + } // for +} + +void LabelFinder::previsit( const ast::CompoundStmt * stmt ) { + previsit( (const ast::Stmt *) stmt ); + Parent::previsit( stmt ); +} + +void LabelFinder::previsit( const ast::DeclStmt * stmt ) { + previsit( (const ast::Stmt *)stmt ); + Parent::previsit( stmt ); +} + +void InsertDtors::previsit( const ast::FunctionDecl * funcDecl ) { + // each function needs to have its own set of labels + GuardValue( labelVars ); + labelVars.clear(); + // LabelFinder does not recurse into FunctionDecl, so need to visit + // its children manually. + if (funcDecl->type) funcDecl->type->accept(finder); + // maybeAccept( funcDecl->type, finder ); + if (funcDecl->stmts) funcDecl->stmts->accept(finder) ; + + // all labels for this function have been collected, insert destructors as appropriate via implicit recursion. +} + +// Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the +// BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope +// at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user +// of the error. See C++ Reference 6.6 Jump Statements for details. +void InsertDtors::handleGoto( const ast::BranchStmt * stmt ) { + // can't do anything for computed goto + if ( stmt->computedTarget ) return; + + assertf( stmt->target.name != "", "BranchStmt missing a label: %s", toString( stmt ).c_str() ); + // S_L = lvars = set of objects in scope at label definition + // S_G = curVars = set of objects in scope at goto statement + ObjectSet & lvars = labelVars[ stmt->target ]; + + DTOR_PRINT( + std::cerr << "at goto label: " << stmt->target.name << std::endl; + std::cerr << "S_G = " << printSet( curVars ) << std::endl; + std::cerr << "S_L = " << printSet( lvars ) << std::endl; + ) + + + // std::set_difference requires that the inputs be sorted. + lvars.sort(); + curVars.sort(); + + ObjectSet diff; + // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty + std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) ); + DTOR_PRINT( + std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl; + ) + if ( ! diff.empty() ) { + SemanticError( stmt, std::string("jump to label '") + stmt->target.name + "' crosses initialization of " + (*diff.begin())->name + " " ); + } // if +} + +void InsertDtors::previsit( const ast::BranchStmt * stmt ) { + switch( stmt->kind ) { + case ast::BranchStmt::Continue: + case ast::BranchStmt::Break: + // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should + // always be empty), but it serves as a small sanity check. + case ast::BranchStmt::Goto: + handleGoto( stmt ); + break; + default: + assert( false ); + } // switch +} + +bool checkWarnings( const ast::FunctionDecl * funcDecl ) { + // only check for warnings if the current function is a user-defined + // constructor or destructor + if ( ! funcDecl ) return false; + if ( ! funcDecl->stmts ) return false; + return CodeGen::isCtorDtor( funcDecl->name ) && ! funcDecl->linkage.is_overrideable; +} + +void GenStructMemberCalls::previsit( const ast::FunctionDecl * funcDecl ) { + GuardValue( function ); + GuardValue( unhandled ); + GuardValue( usedUninit ); + GuardValue( thisParam ); + GuardValue( isCtor ); + GuardValue( structDecl ); + errors = SemanticErrorException(); // clear previous errors + + // need to start with fresh sets + unhandled.clear(); + usedUninit.clear(); + + function = mutate(funcDecl); + // could this be non-unique? + if (function != funcDecl) { + std::cerr << "GenStructMemberCalls: non-unique FunctionDecl " << funcDecl->location << funcDecl->name << std::endl; + } + + isCtor = CodeGen::isConstructor( function->name ); + if ( checkWarnings( function ) ) { + // const ast::FunctionType * type = function->type; + // assert( ! type->params.empty() ); + thisParam = function->params.front().strict_as(); + auto thisType = getPointerBase( thisParam->get_type() ); + auto structType = dynamic_cast< const ast::StructInstType * >( thisType ); + if ( structType ) { + structDecl = structType->base; + for ( auto & member : structDecl->members ) { + if ( auto field = member.as() ) { + // record all of the struct type's members that need to be constructed or + // destructed by the end of the function + unhandled.insert( field ); + } + } + } + } +} + +const ast::DeclWithType * GenStructMemberCalls::postvisit( const ast::FunctionDecl * funcDecl ) { + // remove the unhandled objects from usedUninit, because a call is inserted + // to handle them - only objects that are later constructed are used uninitialized. + std::map< const ast::DeclWithType *, CodeLocation > diff; + // need the comparator since usedUninit and unhandled have different types + struct comp_t { + typedef decltype(usedUninit)::value_type usedUninit_t; + typedef decltype(unhandled)::value_type unhandled_t; + bool operator()(usedUninit_t x, unhandled_t y) { return x.first < y; } + bool operator()(unhandled_t x, usedUninit_t y) { return x < y.first; } + } comp; + std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ), comp ); + for ( auto p : diff ) { + auto member = p.first; + auto loc = p.second; + // xxx - make error message better by also tracking the location that the object is constructed at? + emit( loc, "in ", function->name, ", field ", member->name, " used before being constructed" ); + } + + const CodeLocation loc = funcDecl->location; + + if ( ! unhandled.empty() ) { + auto mutStmts = function->stmts.get_and_mutate(); + // need to explicitly re-add function parameters to the indexer in order to resolve copy constructors + auto guard = makeFuncGuard( [this]() { symtab.enterScope(); }, [this]() { symtab.leaveScope(); } ); + symtab.addFunction( function ); + auto global = transUnit().global; + + // need to iterate through members in reverse in order for + // ctor/dtor statements to come out in the right order + for ( auto & member : reverseIterate( structDecl->members ) ) { + auto field = member.as(); + // skip non-DWT members + if ( ! field ) continue; + // skip non-constructable members + if ( ! tryConstruct( field ) ) continue; + // skip handled members + if ( ! unhandled.count( field ) ) continue; + + // insert and resolve default/copy constructor call for each field that's unhandled + // std::list< const ast::Stmt * > stmt; + ast::Expr * arg2 = nullptr; + if ( function->name == "?{}" && isCopyFunction( function ) ) { + // if copy ctor, need to pass second-param-of-this-function.field + // std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters(); + assert( function->params.size() == 2 ); + arg2 = new ast::MemberExpr(funcDecl->location, field, new ast::VariableExpr(funcDecl->location, function->params.back() ) ); + } + InitExpander_new srcParam( arg2 ); + // cast away reference type and construct field. + ast::Expr * thisExpr = new ast::CastExpr(funcDecl->location, new ast::VariableExpr(funcDecl->location, thisParam ), thisParam->get_type()->stripReferences()); + ast::Expr * memberDest = new ast::MemberExpr(funcDecl->location, field, thisExpr ); + ast::ptr callStmt = SymTab::genImplicitCall( srcParam, memberDest, loc, function->name, field, static_cast(isCtor) ); + + if ( callStmt ) { + // auto & callStmt = stmt.front(); + + try { + callStmt = callStmt->accept( *visitor ); + if ( isCtor ) { + mutStmts->push_front( callStmt ); + } else { // TODO: don't generate destructor function/object for intrinsic calls + // destructor statements should be added at the end + // function->get_statements()->push_back( callStmt ); + + // Optimization: do not need to call intrinsic destructors on members + if ( isIntrinsicSingleArgCallStmt( callStmt ) ) continue; + + // __Destructor _dtor0 = { (void *)&b.a1, (void (*)(void *)_destroy_A }; + std::list< ast::ptr > stmtsToAdd; + + static UniqueName memberDtorNamer = { "__memberDtor" }; + assertf( global.dtorStruct, "builtin __Destructor not found." ); + assertf( global.dtorDestroy, "builtin __destroy_Destructor not found." ); + + ast::Expr * thisExpr = new ast::CastExpr( new ast::AddressExpr( new ast::VariableExpr(loc, thisParam ) ), new ast::PointerType( new ast::VoidType(), ast::CV::Qualifiers() ) ); + ast::Expr * dtorExpr = new ast::VariableExpr(loc, getDtorFunc( thisParam, callStmt, stmtsToAdd ) ); + + // cast destructor pointer to void (*)(void *), to silence GCC incompatible pointer warnings + auto dtorFtype = new ast::FunctionType(); + dtorFtype->params.emplace_back( new ast::PointerType( new ast::VoidType() ) ); + auto dtorType = new ast::PointerType( dtorFtype ); + + auto destructor = new ast::ObjectDecl(loc, memberDtorNamer.newName(), new ast::StructInstType( global.dtorStruct ), new ast::ListInit(loc, { new ast::SingleInit(loc, thisExpr ), new ast::SingleInit(loc, new ast::CastExpr( dtorExpr, dtorType ) ) } ) ); + destructor->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr( loc, global.dtorDestroy ) } ) ); + mutStmts->push_front( new ast::DeclStmt(loc, destructor ) ); + mutStmts->kids.splice( mutStmts->kids.begin(), stmtsToAdd ); + } + } catch ( SemanticErrorException & error ) { + emit( funcDecl->location, "in ", function->name , ", field ", field->name, " not explicitly ", isCtor ? "constructed" : "destructed", " and no ", isCtor ? "default constructor" : "destructor", " found" ); + } + } + } + function->stmts = mutStmts; + } + if (! errors.isEmpty()) { + throw errors; + } + // return funcDecl; + return function; +} + +/// true if expr is effectively just the 'this' parameter +bool isThisExpression( const ast::Expr * expr, const ast::DeclWithType * thisParam ) { + // TODO: there are more complicated ways to pass 'this' to a constructor, e.g. &*, *&, etc. + if ( auto varExpr = dynamic_cast< const ast::VariableExpr * >( expr ) ) { + return varExpr->var == thisParam; + } else if ( auto castExpr = dynamic_cast< const ast::CastExpr * > ( expr ) ) { + return isThisExpression( castExpr->arg, thisParam ); + } + return false; +} + +/// returns a MemberExpr if expr is effectively just member access on the 'this' parameter, else nullptr +const ast::MemberExpr * isThisMemberExpr( const ast::Expr * expr, const ast::DeclWithType * thisParam ) { + if ( auto memberExpr = dynamic_cast< const ast::MemberExpr * >( expr ) ) { + if ( isThisExpression( memberExpr->aggregate, thisParam ) ) { + return memberExpr; + } + } else if ( auto castExpr = dynamic_cast< const ast::CastExpr * >( expr ) ) { + return isThisMemberExpr( castExpr->arg, thisParam ); + } + return nullptr; +} + +void GenStructMemberCalls::previsit( const ast::ApplicationExpr * appExpr ) { + if ( ! checkWarnings( function ) ) { + visit_children = false; + return; + } + + std::string fname = getFunctionName( appExpr ); + if ( fname == function->name ) { + // call to same kind of function + const ast::Expr * firstParam = appExpr->args.front(); + + if ( isThisExpression( firstParam, thisParam ) ) { + // if calling another constructor on thisParam, assume that function handles + // all members - if it doesn't a warning will appear in that function. + unhandled.clear(); + } else if ( auto memberExpr = isThisMemberExpr( firstParam, thisParam ) ) { + // if first parameter is a member expression on the this parameter, + // then remove the member from unhandled set. + if ( isThisExpression( memberExpr->aggregate, thisParam ) ) { + unhandled.erase( memberExpr->member ); + } + } + } +} + +void GenStructMemberCalls::previsit( const ast::MemberExpr * memberExpr ) { + if ( ! checkWarnings( function ) || ! isCtor ) { + visit_children = false; + return; + } + + if ( isThisExpression( memberExpr->aggregate, thisParam ) ) { + if ( unhandled.count( memberExpr->member ) ) { + // emit a warning because a member was used before it was constructed + usedUninit.insert( { memberExpr->member, memberExpr->location } ); + } + } +} + +template< typename... Params > +void GenStructMemberCalls::emit( CodeLocation loc, const Params &... params ) { + SemanticErrorException err( loc, toString( params... ) ); + errors.append( err ); +} + +const ast::Expr * GenStructMemberCalls::postvisit( const ast::UntypedExpr * untypedExpr ) { + // xxx - functions returning ast::ptr seems wrong... + auto res = ResolvExpr::findVoidExpression( untypedExpr, { symtab, transUnit().global } ); + return res.release(); +} + +void InsertImplicitCalls::previsit(const ast::UniqueExpr * unqExpr) { + if (visitedIds.count(unqExpr->id)) visit_children = false; + else visitedIds.insert(unqExpr->id); +} + +const ast::Expr * FixCtorExprs::postvisit( const ast::ConstructorExpr * ctorExpr ) { + const CodeLocation loc = ctorExpr->location; + static UniqueName tempNamer( "_tmp_ctor_expr" ); + // xxx - is the size check necessary? + assert( ctorExpr->result && ctorExpr->result->size() == 1 ); + + // xxx - this can be TupleAssignExpr now. Need to properly handle this case. + // take possession of expr and env + ast::ptr callExpr = ctorExpr->callExpr.strict_as(); + ast::ptr env = ctorExpr->env; + // ctorExpr->set_callExpr( nullptr ); + // ctorExpr->set_env( nullptr ); + + // xxx - ideally we would reuse the temporary generated from the copy constructor passes from within firstArg if it exists and not generate a temporary if it's unnecessary. + auto tmp = new ast::ObjectDecl(loc, tempNamer.newName(), callExpr->args.front()->result ); + declsToAddBefore.push_back( tmp ); + + // build assignment and replace constructor's first argument with new temporary + auto mutCallExpr = callExpr.get_and_mutate(); + const ast::Expr * firstArg = callExpr->args.front(); + ast::Expr * assign = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "?=?" ), { new ast::AddressExpr(loc, new ast::VariableExpr(loc, tmp ) ), new ast::AddressExpr( firstArg ) } ); + firstArg = new ast::VariableExpr(loc, tmp ); + mutCallExpr->args.front() = firstArg; + + // resolve assignment and dispose of new env + auto resolved = ResolvExpr::findVoidExpression( assign, { symtab, transUnit().global } ); + auto mut = resolved.get_and_mutate(); + assertf(resolved.get() == mut, "newly resolved expression must be unique"); + mut->env = nullptr; + + // for constructor expr: + // T x; + // x{}; + // results in: + // T x; + // T & tmp; + // &tmp = &x, ?{}(tmp), tmp + ast::CommaExpr * commaExpr = new ast::CommaExpr(loc, resolved, new ast::CommaExpr(loc, mutCallExpr, new ast::VariableExpr(loc, tmp ) ) ); + commaExpr->env = env; + return commaExpr; +} + } // namespace @@ -274,1110 +1380,4 @@ } -namespace { - /// find and return the destructor used in `input`. If `input` is not a simple destructor call, generate a thunk - /// that wraps the destructor, insert it into `stmtsToAdd` and return the new function declaration - const ast::DeclWithType * getDtorFunc( const ast::ObjectDecl * objDecl, const ast::Stmt * input, std::list< ast::ptr > & stmtsToAdd ) { - const CodeLocation loc = input->location; - // unwrap implicit statement wrapper - // Statement * dtor = input; - assert( input ); - // std::list< const ast::Expr * > matches; - auto matches = collectCtorDtorCalls( input ); - - if ( dynamic_cast< const ast::ExprStmt * >( input ) ) { - // only one destructor call in the expression - if ( matches.size() == 1 ) { - auto func = getFunction( matches.front() ); - assertf( func, "getFunction failed to find function in %s", toString( matches.front() ).c_str() ); - - // cleanup argument must be a function, not an object (including function pointer) - if ( auto dtorFunc = dynamic_cast< const ast::FunctionDecl * > ( func ) ) { - if ( dtorFunc->type->forall.empty() ) { - // simple case where the destructor is a monomorphic function call - can simply - // use that function as the cleanup function. - return func; - } - } - } - } - - // otherwise the cleanup is more complicated - need to build a single argument cleanup function that - // wraps the more complicated code. - static UniqueName dtorNamer( "__cleanup_dtor" ); - std::string name = dtorNamer.newName(); - ast::FunctionDecl * dtorFunc = genDefaultFunc( loc, name, objDecl->type->stripReferences(), false ); - stmtsToAdd.push_back( new ast::DeclStmt(loc, dtorFunc ) ); - - // the original code contains uses of objDecl - replace them with the newly generated 'this' parameter. - const ast::ObjectDecl * thisParam = getParamThis( dtorFunc ); - const ast::Expr * replacement = new ast::VariableExpr( loc, thisParam ); - - auto base = replacement->result->stripReferences(); - if ( dynamic_cast< const ast::ArrayType * >( base ) || dynamic_cast< const ast::TupleType * > ( base ) ) { - // need to cast away reference for array types, since the destructor is generated without the reference type, - // and for tuple types since tuple indexing does not work directly on a reference - replacement = new ast::CastExpr( replacement, base ); - } - auto dtor = ast::DeclReplacer::replace( input, ast::DeclReplacer::ExprMap{ std::make_pair( objDecl, replacement ) } ); - auto mutStmts = dtorFunc->stmts.get_and_mutate(); - mutStmts->push_back(strict_dynamic_cast( dtor )); - dtorFunc->stmts = mutStmts; - - return dtorFunc; - } - - void FixInit::fixInitializers( ast::TranslationUnit & translationUnit ) { - ast::Pass fixer; - - // can't use mutateAll, because need to insert declarations at top-level - // can't use DeclMutator, because sometimes need to insert IfStmt, etc. - SemanticErrorException errors; - for ( auto i = translationUnit.decls.begin(); i != translationUnit.decls.end(); ++i ) { - try { - // maybeAccept( *i, fixer ); translationUnit should never contain null - *i = (*i)->accept(fixer); - translationUnit.decls.splice( i, fixer.core.staticDtorDecls ); - } catch( SemanticErrorException &e ) { - errors.append( e ); - } // try - } // for - if ( ! errors.isEmpty() ) { - throw errors; - } // if - } - - const ast::StmtExpr * StmtExprResult::previsit( const ast::StmtExpr * stmtExpr ) { - // we might loose the result expression here so add a pointer to trace back - assert( stmtExpr->result ); - const ast::Type * result = stmtExpr->result; - if ( ! result->isVoid() ) { - auto mutExpr = mutate(stmtExpr); - const ast::CompoundStmt * body = mutExpr->stmts; - assert( ! body->kids.empty() ); - mutExpr->resultExpr = body->kids.back().strict_as(); - return mutExpr; - } - return stmtExpr; - } - - ast::Stmt * SplitExpressions::postvisit( const ast::ExprStmt * stmt ) { - // wrap each top-level ExprStmt in a block so that destructors for argument and return temporaries are destroyed - // in the correct places - ast::CompoundStmt * ret = new ast::CompoundStmt( stmt->location, { stmt } ); - return ret; - } - - void SplitExpressions::previsit( const ast::TupleAssignExpr * ) { - // don't do this within TupleAssignExpr, since it is already broken up into multiple expressions - visit_children = false; - } - - // Relatively simple structural comparison for expressions, needed to determine - // if two expressions are "the same" (used to determine if self assignment occurs) - struct StructuralChecker { - // Strip all casts and then dynamic_cast. - template - static const T * cast( const ast::Expr * expr ) { - // this might be too permissive. It's possible that only particular casts are relevant. - while ( auto cast = dynamic_cast< const ast::CastExpr * >( expr ) ) { - expr = cast->arg; - } - return dynamic_cast< const T * >( expr ); - } - - void previsit( const ast::Expr * ) { - // anything else does not qualify - result = false; - } - - // ignore casts - void previsit( const ast::CastExpr * ) {} - - void previsit( const ast::MemberExpr * memExpr ) { - if ( auto otherMember = cast< ast::MemberExpr >( other ) ) { - if ( otherMember->member == memExpr->member ) { - other = otherMember->aggregate; - return; - } - } - result = false; - } - - void previsit( const ast::VariableExpr * varExpr ) { - if ( auto otherVar = cast< ast::VariableExpr >( other ) ) { - if ( otherVar->var == varExpr->var ) { - return; - } - } - result = false; - } - - void previsit( const ast::AddressExpr * ) { - if ( auto addrExpr = cast< ast::AddressExpr >( other ) ) { - other = addrExpr->arg; - return; - } - result = false; - } - - const ast::Expr * other; - bool result = true; - StructuralChecker( const ast::Expr * other ) : other(other) {} - }; - - bool structurallySimilar( const ast::Expr * e1, const ast::Expr * e2 ) { - return ast::Pass::read( e1, e2 ); - } - - void SelfAssignChecker::previsit( const ast::ApplicationExpr * appExpr ) { - auto function = getFunction( appExpr ); - // Doesn't use isAssignment, because ?+=?, etc. should not count as self-assignment. - if ( function->name == "?=?" && appExpr->args.size() == 2 - // Check for structural similarity (same variable use, ignore casts, etc. - // (but does not look too deeply, anything looking like a function is off limits). - && structurallySimilar( appExpr->args.front(), appExpr->args.back() ) ) { - SemanticWarning( appExpr->location, Warning::SelfAssignment, toCString( appExpr->args.front() ) ); - } - } - - const ast::Expr * InsertImplicitCalls::postvisit( const ast::ApplicationExpr * appExpr ) { - if ( auto function = appExpr->func.as() ) { - if ( function->var->linkage.is_builtin ) { - // optimization: don't need to copy construct in order to call intrinsic functions - return appExpr; - } else if ( auto funcDecl = function->var.as() ) { - auto ftype = dynamic_cast< const ast::FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) ); - assertf( ftype, "Function call without function type: %s", toString( funcDecl ).c_str() ); - if ( CodeGen::isConstructor( funcDecl->name ) && ftype->params.size() == 2 ) { - auto t1 = getPointerBase( ftype->params.front() ); - auto t2 = ftype->params.back(); - assert( t1 ); - - if ( ResolvExpr::typesCompatible( t1, t2 ) ) { - // optimization: don't need to copy construct in order to call a copy constructor - return appExpr; - } // if - } else if ( CodeGen::isDestructor( funcDecl->name ) ) { - // correctness: never copy construct arguments to a destructor - return appExpr; - } // if - } // if - } // if - CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; ) - - // wrap each function call so that it is easy to identify nodes that have to be copy constructed - ast::ptr tmp = appExpr->env; - auto mutExpr = mutate(appExpr); - mutExpr->env = nullptr; - - auto expr = new ast::ImplicitCopyCtorExpr( appExpr->location, mutExpr ); - // Move the type substitution to the new top-level. The substitution - // is needed to obtain the type of temporary variables so that copy - // constructor calls can be resolved. - expr->env = tmp; - return expr; - } - - void ResolveCopyCtors::previsit(const ast::Expr * expr) { - if ( nullptr == expr->env ) { - return; - } - GuardValue( env ) = expr->env->clone(); - GuardValue( envModified ) = false; - } - - const ast::Expr * ResolveCopyCtors::postvisit(const ast::Expr * expr) { - // No local environment, skip. - if ( nullptr == expr->env ) { - return expr; - // Environment was modified, mutate and replace. - } else if ( envModified ) { - auto mutExpr = mutate(expr); - mutExpr->env = env; - return mutExpr; - // Environment was not mutated, delete the shallow copy before guard. - } else { - delete env; - return expr; - } - } - - bool ResolveCopyCtors::skipCopyConstruct( const ast::Type * type ) { return ! isConstructable( type ); } - - const ast::Expr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, const ast::ObjectDecl * var, const ast::Expr * cpArg ) { - assert( var ); - assert( var->isManaged() ); - assert( !cpArg || cpArg->isManaged() ); - // arrays are not copy constructed, so this should always be an ExprStmt - ast::ptr< ast::Stmt > stmt = genCtorDtor(var->location, fname, var, cpArg ); - assertf( stmt, "ResolveCopyCtors: genCtorDtor returned nullptr: %s / %s / %s", fname.c_str(), toString( var ).c_str(), toString( cpArg ).c_str() ); - auto exprStmt = stmt.strict_as()->callStmt.strict_as(); - ast::ptr untyped = exprStmt->expr; // take ownership of expr - - // resolve copy constructor - // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed - // (VariableExpr and already resolved expression) - CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; ) - ast::ptr resolved = ResolvExpr::findVoidExpression(untyped, { symtab, transUnit().global } ); - assert( resolved ); - if ( resolved->env ) { - // Extract useful information and discard new environments. Keeping them causes problems in PolyMutator passes. - env->add( *resolved->env ); - envModified = true; - auto mut = mutate(resolved.get()); - assertf(mut == resolved.get(), "newly resolved expression must be unique"); - mut->env = nullptr; - } // if - if ( auto assign = resolved.as() ) { - // fix newly generated StmtExpr - previsit( assign->stmtExpr ); - } - return resolved.release(); - } - - ast::ptr ResolveCopyCtors::copyConstructArg( - const ast::Expr * arg, const ast::ImplicitCopyCtorExpr * impCpCtorExpr, const ast::Type * formal ) - { - static UniqueName tempNamer("_tmp_cp"); - const CodeLocation loc = impCpCtorExpr->location; - // CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *env << std::endl; ) - assert( arg->result ); - ast::ptr result = arg->result; - if ( skipCopyConstruct( result ) ) return arg; // skip certain non-copyable types - - // type may involve type variables, so apply type substitution to get temporary variable's actual type, - // since result type may not be substituted (e.g., if the type does not appear in the parameter list) - // Use applyFree so that types bound in function pointers are not substituted, e.g. in forall(dtype T) void (*)(T). - - // xxx - this originally mutates arg->result in place. is it correct? - assert( env ); - result = env->applyFree( result.get() ).node; - auto mutResult = result.get_and_mutate(); - mutResult->set_const(false); - - auto mutArg = mutate(arg); - mutArg->result = mutResult; - - ast::ptr guard = mutArg; - - ast::ptr tmp = new ast::ObjectDecl(loc, "__tmp", mutResult, nullptr ); - - // create and resolve copy constructor - CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; ) - auto cpCtor = makeCtorDtor( "?{}", tmp, mutArg ); - - if ( auto appExpr = dynamic_cast< const ast::ApplicationExpr * >( cpCtor ) ) { - // if the chosen constructor is intrinsic, the copy is unnecessary, so - // don't create the temporary and don't call the copy constructor - auto function = appExpr->func.strict_as(); - if ( function->var->linkage == ast::Linkage::Intrinsic ) { - // arguments that need to be boxed need a temporary regardless of whether the copy constructor is intrinsic, - // so that the object isn't changed inside of the polymorphic function - if ( ! GenPoly::needsBoxing( formal, result, impCpCtorExpr->callExpr, env ) ) { - // xxx - should arg->result be mutated? see comment above. - return guard; - } - } - } - - // set a unique name for the temporary once it's certain the call is necessary - auto mut = tmp.get_and_mutate(); - assertf (mut == tmp, "newly created ObjectDecl must be unique"); - mut->name = tempNamer.newName(); - - // replace argument to function call with temporary - stmtsToAddBefore.push_back( new ast::DeclStmt(loc, tmp ) ); - arg = cpCtor; - return destructRet( tmp, arg ); - - // impCpCtorExpr->dtors.push_front( makeCtorDtor( "^?{}", tmp ) ); - } - - ast::Expr * ResolveCopyCtors::destructRet( const ast::ObjectDecl * ret, const ast::Expr * arg ) { - auto global = transUnit().global; - // TODO: refactor code for generating cleanup attribute, since it's common and reused in ~3-4 places - // check for existing cleanup attribute before adding another(?) - // need to add __Destructor for _tmp_cp variables as well - - assertf( global.dtorStruct, "Destructor generation requires __Destructor definition." ); - assertf( global.dtorStruct->members.size() == 2, "__Destructor definition does not have expected fields." ); - assertf( global.dtorDestroy, "Destructor generation requires __destroy_Destructor." ); - - const CodeLocation loc = ret->location; - - // generate a __Destructor for ret that calls the destructor - auto res = makeCtorDtor( "^?{}", ret ); - auto dtor = mutate(res); - - // if the chosen destructor is intrinsic, elide the generated dtor handler - if ( arg && isIntrinsicCallExpr( dtor ) ) { - return new ast::CommaExpr(loc, arg, new ast::VariableExpr(loc, ret ) ); - } - - if ( ! dtor->env ) dtor->env = maybeClone( env ); - auto dtorFunc = getDtorFunc( ret, new ast::ExprStmt(loc, dtor ), stmtsToAddBefore ); - - auto dtorStructType = new ast::StructInstType( global.dtorStruct ); - - // what does this do??? - dtorStructType->params.push_back( new ast::TypeExpr(loc, new ast::VoidType() ) ); - - // cast destructor pointer to void (*)(void *), to silence GCC incompatible pointer warnings - auto dtorFtype = new ast::FunctionType(); - dtorFtype->params.push_back( new ast::PointerType(new ast::VoidType( ) ) ); - auto dtorType = new ast::PointerType( dtorFtype ); - - static UniqueName namer( "_ret_dtor" ); - auto retDtor = new ast::ObjectDecl(loc, namer.newName(), dtorStructType, new ast::ListInit(loc, { new ast::SingleInit(loc, ast::ConstantExpr::null(loc) ), new ast::SingleInit(loc, new ast::CastExpr( new ast::VariableExpr(loc, dtorFunc ), dtorType ) ) } ) ); - retDtor->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr(loc, global.dtorDestroy ) } ) ); - stmtsToAddBefore.push_back( new ast::DeclStmt(loc, retDtor ) ); - - if ( arg ) { - auto member = new ast::MemberExpr(loc, global.dtorStruct->members.front().strict_as(), new ast::VariableExpr(loc, retDtor ) ); - auto object = new ast::CastExpr( new ast::AddressExpr( new ast::VariableExpr(loc, ret ) ), new ast::PointerType(new ast::VoidType() ) ); - ast::Expr * assign = createBitwiseAssignment( member, object ); - return new ast::CommaExpr(loc, new ast::CommaExpr(loc, arg, assign ), new ast::VariableExpr(loc, ret ) ); - } - return nullptr; - // impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) ); - } - - const ast::Expr * ResolveCopyCtors::postvisit( const ast::ImplicitCopyCtorExpr *impCpCtorExpr ) { - CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; ) - - ast::ApplicationExpr * appExpr = mutate(impCpCtorExpr->callExpr.get()); - const ast::ObjectDecl * returnDecl = nullptr; - const CodeLocation loc = appExpr->location; - - // take each argument and attempt to copy construct it. - auto ftype = GenPoly::getFunctionType( appExpr->func->result ); - assert( ftype ); - auto & params = ftype->params; - auto iter = params.begin(); - for ( auto & arg : appExpr->args ) { - const ast::Type * formal = nullptr; - if ( iter != params.end() ) { // does not copy construct C-style variadic arguments - // DeclarationWithType * param = *iter++; - formal = *iter++; - } - - arg = copyConstructArg( arg, impCpCtorExpr, formal ); - } // for - - // each return value from the call needs to be connected with an ObjectDecl at the call site, which is - // initialized with the return value and is destructed later - // xxx - handle named return values? - const ast::Type * result = appExpr->result; - if ( ! result->isVoid() ) { - static UniqueName retNamer("_tmp_cp_ret"); - auto subResult = env->apply( result ).node; - auto ret = new ast::ObjectDecl(loc, retNamer.newName(), subResult, nullptr ); - auto mutType = mutate(ret->type.get()); - mutType->set_const( false ); - ret->type = mutType; - returnDecl = ret; - stmtsToAddBefore.push_back( new ast::DeclStmt(loc, ret ) ); - CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; ) - } // for - CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; ) - // ------------------------------------------------------ - - CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; ) - - // detach fields from wrapper node so that it can be deleted without deleting too much - - // xxx - actual env might be somewhere else, need to keep invariant - - // deletion of wrapper should be handled by pass template now - - // impCpCtorExpr->callExpr = nullptr; - assert (appExpr->env == nullptr); - appExpr->env = impCpCtorExpr->env; - // std::swap( impCpCtorExpr->env, appExpr->env ); - // assert( impCpCtorExpr->env == nullptr ); - // delete impCpCtorExpr; - - if ( returnDecl ) { - ast::Expr * assign = createBitwiseAssignment( new ast::VariableExpr(loc, returnDecl ), appExpr ); - if ( ! dynamic_cast< const ast::ReferenceType * >( result ) ) { - // destructing reference returns is bad because it can cause multiple destructor calls to the same object - the returned object is not a temporary - assign = destructRet( returnDecl, assign ); - assert(assign); - } else { - assign = new ast::CommaExpr(loc, assign, new ast::VariableExpr(loc, returnDecl ) ); - } - // move env from appExpr to retExpr - // std::swap( assign->env, appExpr->env ); - assign->env = appExpr->env; - // actual env is handled by common routine that replaces WithTypeSubstitution - return postvisit((const ast::Expr *)assign); - } else { - return postvisit((const ast::Expr *)appExpr); - } // if - } - - const ast::StmtExpr * ResolveCopyCtors::previsit( const ast::StmtExpr * _stmtExpr ) { - // function call temporaries should be placed at statement-level, rather than nested inside of a new statement expression, - // since temporaries can be shared across sub-expressions, e.g. - // [A, A] f(); // decl - // g([A] x, [A] y); // decl - // g(f()); // call - // f is executed once, so the return temporary is shared across the tuple constructors for x and y. - // Explicitly mutating children instead of mutating the inner compound statement forces the temporaries to be added - // to the outer context, rather than inside of the statement expression. - - // call the common routine that replaces WithTypeSubstitution - previsit((const ast::Expr *) _stmtExpr); - - visit_children = false; - const CodeLocation loc = _stmtExpr->location; - - assert( env ); - - symtab.enterScope(); - // visit all statements - auto stmtExpr = mutate(_stmtExpr); - auto mutStmts = mutate(stmtExpr->stmts.get()); - - auto & stmts = mutStmts->kids; - for ( auto & stmt : stmts ) { - stmt = stmt->accept( *visitor ); - } // for - stmtExpr->stmts = mutStmts; - symtab.leaveScope(); - - assert( stmtExpr->result ); - // const ast::Type * result = stmtExpr->result; - if ( ! stmtExpr->result->isVoid() ) { - static UniqueName retNamer("_tmp_stmtexpr_ret"); - - // result = result->clone(); - auto result = env->apply( stmtExpr->result.get() ).node; - if ( ! InitTweak::isConstructable( result ) ) { - // delete result; - return stmtExpr; - } - auto mutResult = result.get_and_mutate(); - mutResult->set_const(false); - - // create variable that will hold the result of the stmt expr - auto ret = new ast::ObjectDecl(loc, retNamer.newName(), mutResult, nullptr ); - stmtsToAddBefore.push_back( new ast::DeclStmt(loc, ret ) ); - - assertf( - stmtExpr->resultExpr, - "Statement-Expression should have a resulting expression at %s:%d", - stmtExpr->location.filename.c_str(), - stmtExpr->location.first_line - ); - - const ast::ExprStmt * last = stmtExpr->resultExpr; - // xxx - if this is non-unique, need to copy while making resultExpr ref - assertf(last->unique(), "attempt to modify weakly shared statement"); - auto mutLast = mutate(last); - // above assertion means in-place mutation is OK - try { - mutLast->expr = makeCtorDtor( "?{}", ret, mutLast->expr ); - } catch(...) { - std::cerr << "*CFA internal error: "; - std::cerr << "can't resolve implicit constructor"; - std::cerr << " at " << stmtExpr->location.filename; - std::cerr << ":" << stmtExpr->location.first_line << std::endl; - - abort(); - } - - // add destructors after current statement - stmtsToAddAfter.push_back( new ast::ExprStmt(loc, makeCtorDtor( "^?{}", ret ) ) ); - - // must have a non-empty body, otherwise it wouldn't have a result - assert( ! stmts.empty() ); - - // if there is a return decl, add a use as the last statement; will not have return decl on non-constructable returns - stmts.push_back( new ast::ExprStmt(loc, new ast::VariableExpr(loc, ret ) ) ); - } // if - - assert( stmtExpr->returnDecls.empty() ); - assert( stmtExpr->dtors.empty() ); - - return stmtExpr; - } - - // to prevent warnings ('_unq0' may be used uninitialized in this function), - // insert an appropriate zero initializer for UniqueExpr temporaries. - ast::Init * makeInit( const ast::Type * t, CodeLocation const & loc ) { - if ( auto inst = dynamic_cast< const ast::StructInstType * >( t ) ) { - // initizer for empty struct must be empty - if ( inst->base->members.empty() ) { - return new ast::ListInit( loc, {} ); - } - } else if ( auto inst = dynamic_cast< const ast::UnionInstType * >( t ) ) { - // initizer for empty union must be empty - if ( inst->base->members.empty() ) { - return new ast::ListInit( loc, {} ); - } - } - - return new ast::ListInit( loc, { - new ast::SingleInit( loc, ast::ConstantExpr::from_int( loc, 0 ) ) - } ); - } - - const ast::UniqueExpr * ResolveCopyCtors::previsit( const ast::UniqueExpr * unqExpr ) { - visit_children = false; - // xxx - hack to prevent double-handling of unique exprs, otherwise too many temporary variables and destructors are generated - static std::unordered_map< int, const ast::UniqueExpr * > unqMap; - auto mutExpr = mutate(unqExpr); - if ( ! unqMap.count( unqExpr->id ) ) { - // resolve expr and find its - - auto impCpCtorExpr = mutExpr->expr.as(); - // PassVisitor fixer; - - mutExpr->expr = mutExpr->expr->accept( *visitor ); - // it should never be necessary to wrap a void-returning expression in a UniqueExpr - if this assumption changes, this needs to be rethought - assert( unqExpr->result ); - if ( impCpCtorExpr ) { - auto comma = unqExpr->expr.strict_as(); - auto var = comma->arg2.strict_as(); - // note the variable used as the result from the call - mutExpr->var = var; - } else { - // expr isn't a call expr, so create a new temporary variable to use to hold the value of the unique expression - mutExpr->object = new ast::ObjectDecl( mutExpr->location, toString("_unq", mutExpr->id), mutExpr->result, makeInit( mutExpr->result, mutExpr->location ) ); - mutExpr->var = new ast::VariableExpr( mutExpr->location, mutExpr->object ); - } - - unqMap[mutExpr->id] = mutExpr; - } else { - // take data from other UniqueExpr to ensure consistency - // delete unqExpr->get_expr(); - mutExpr->expr = unqMap[mutExpr->id]->expr; - // delete unqExpr->result; - mutExpr->result = mutExpr->expr->result; - } - return mutExpr; - } - - const ast::DeclWithType * FixInit::postvisit( const ast::ObjectDecl *_objDecl ) { - const CodeLocation loc = _objDecl->location; - - // since this removes the init field from objDecl, it must occur after children are mutated (i.e. postvisit) - if ( ast::ptr ctorInit = _objDecl->init.as() ) { - auto objDecl = mutate(_objDecl); - - // could this be non-unique? - if (objDecl != _objDecl) { - std::cerr << "FixInit: non-unique object decl " << objDecl->location << objDecl->name << std::endl; - } - // a decision should have been made by the resolver, so ctor and init are not both non-NULL - assert( ! ctorInit->ctor || ! ctorInit->init ); - if ( const ast::Stmt * ctor = ctorInit->ctor ) { - if ( objDecl->storage.is_static ) { - addDataSectionAttribute(objDecl); - // originally wanted to take advantage of gcc nested functions, but - // we get memory errors with this approach. To remedy this, the static - // variable is hoisted when the destructor needs to be called. - // - // generate: - // static T __objName_static_varN; - // void __objName_dtor_atexitN() { - // __dtor__...; - // } - // int f(...) { - // ... - // static bool __objName_uninitialized = true; - // if (__objName_uninitialized) { - // __ctor(__objName); - // __objName_uninitialized = false; - // atexit(__objName_dtor_atexitN); - // } - // ... - // } - - static UniqueName dtorCallerNamer( "_dtor_atexit" ); - - // static bool __objName_uninitialized = true - auto boolType = new ast::BasicType( ast::BasicType::Kind::Bool ); - auto boolInitExpr = new ast::SingleInit(loc, ast::ConstantExpr::from_int(loc, 1 ) ); - auto isUninitializedVar = new ast::ObjectDecl(loc, objDecl->mangleName + "_uninitialized", boolType, boolInitExpr, ast::Storage::Static, ast::Linkage::Cforall); - isUninitializedVar->fixUniqueId(); - - // __objName_uninitialized = false; - auto setTrue = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "?=?" ) ); - setTrue->args.push_back( new ast::VariableExpr(loc, isUninitializedVar ) ); - setTrue->args.push_back( ast::ConstantExpr::from_int(loc, 0 ) ); - - // generate body of if - auto initStmts = new ast::CompoundStmt(loc); - auto & body = initStmts->kids; - body.push_back( ctor ); - body.push_back( new ast::ExprStmt(loc, setTrue ) ); - - // put it all together - auto ifStmt = new ast::IfStmt(loc, new ast::VariableExpr(loc, isUninitializedVar ), initStmts, 0 ); - stmtsToAddAfter.push_back( new ast::DeclStmt(loc, isUninitializedVar ) ); - stmtsToAddAfter.push_back( ifStmt ); - - const ast::Stmt * dtor = ctorInit->dtor; - - // these should be automatically managed once reassigned - // objDecl->set_init( nullptr ); - // ctorInit->set_ctor( nullptr ); - // ctorInit->set_dtor( nullptr ); - if ( dtor ) { - // if the object has a non-trivial destructor, have to - // hoist it and the object into the global space and - // call the destructor function with atexit. - - // Statement * dtorStmt = dtor->clone(); - - // void __objName_dtor_atexitN(...) {...} - ast::FunctionDecl * dtorCaller = new ast::FunctionDecl(loc, objDecl->mangleName + dtorCallerNamer.newName(), {}, {}, {}, new ast::CompoundStmt(loc, {dtor}), ast::Storage::Static, ast::Linkage::C ); - dtorCaller->fixUniqueId(); - // dtorCaller->stmts->push_back( dtor ); - - // atexit(dtor_atexit); - auto callAtexit = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "atexit" ) ); - callAtexit->args.push_back( new ast::VariableExpr(loc, dtorCaller ) ); - - body.push_back( new ast::ExprStmt(loc, callAtexit ) ); - - // hoist variable and dtor caller decls to list of decls that will be added into global scope - staticDtorDecls.push_back( objDecl ); - staticDtorDecls.push_back( dtorCaller ); - - // need to rename object uniquely since it now appears - // at global scope and there could be multiple function-scoped - // static variables with the same name in different functions. - // Note: it isn't sufficient to modify only the mangleName, because - // then subsequent Indexer passes can choke on seeing the object's name - // if another object has the same name and type. An unfortunate side-effect - // of renaming the object is that subsequent NameExprs may fail to resolve, - // but there shouldn't be any remaining past this point. - static UniqueName staticNamer( "_static_var" ); - objDecl->name = objDecl->name + staticNamer.newName(); - objDecl->mangleName = Mangle::mangle( objDecl ); - objDecl->init = nullptr; - - // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope - // create a new object which is never used - static UniqueName dummyNamer( "_dummy" ); - auto dummy = new ast::ObjectDecl(loc, dummyNamer.newName(), new ast::PointerType(new ast::VoidType()), nullptr, ast::Storage::Static, ast::Linkage::Cforall, 0, { new ast::Attribute("unused") } ); - // delete ctorInit; - return dummy; - } else { - objDecl->init = nullptr; - return objDecl; - } - } else { - auto implicit = strict_dynamic_cast< const ast::ImplicitCtorDtorStmt * > ( ctor ); - auto ctorStmt = implicit->callStmt.as(); - const ast::ApplicationExpr * ctorCall = nullptr; - if ( ctorStmt && (ctorCall = isIntrinsicCallExpr( ctorStmt->expr )) && ctorCall->args.size() == 2 ) { - // clean up intrinsic copy constructor calls by making them into SingleInits - const ast::Expr * ctorArg = ctorCall->args.back(); - // ctorCall should be gone afterwards - auto mutArg = mutate(ctorArg); - mutArg->env = ctorCall->env; - // std::swap( ctorArg->env, ctorCall->env ); - objDecl->init = new ast::SingleInit(loc, mutArg ); - - // ctorCall->args.pop_back(); - } else { - stmtsToAddAfter.push_back( ctor ); - objDecl->init = nullptr; - // ctorInit->ctor = nullptr; - } - - const ast::Stmt * dtor = ctorInit->dtor; - if ( dtor ) { - auto implicit = strict_dynamic_cast< const ast::ImplicitCtorDtorStmt * >( dtor ); - const ast::Stmt * dtorStmt = implicit->callStmt; - - // don't need to call intrinsic dtor, because it does nothing, but - // non-intrinsic dtors must be called - if ( ! isIntrinsicSingleArgCallStmt( dtorStmt ) ) { - // set dtor location to the object's location for error messages - auto dtorFunc = getDtorFunc( objDecl, dtorStmt, stmtsToAddBefore ); - objDecl->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr(loc, dtorFunc ) } ) ); - // ctorInit->dtor = nullptr; - } // if - } - } // if - } else if ( const ast::Init * init = ctorInit->init ) { - objDecl->init = init; - // ctorInit->init = nullptr; - } else { - // no constructor and no initializer, which is okay - objDecl->init = nullptr; - } // if - // delete ctorInit; - return objDecl; - } // if - return _objDecl; - } - - void ObjDeclCollector::previsit( const ast::CompoundStmt * ) { - GuardValue( curVars ); - } - - void ObjDeclCollector::previsit( const ast::DeclStmt * stmt ) { - // keep track of all variables currently in scope - if ( auto objDecl = stmt->decl.as() ) { - curVars.push_back( objDecl ); - } // if - } - - void LabelFinder::previsit( const ast::Stmt * stmt ) { - // for each label, remember the variables in scope at that label. - for ( auto l : stmt->labels ) { - vars[l] = curVars; - } // for - } - - void LabelFinder::previsit( const ast::CompoundStmt * stmt ) { - previsit( (const ast::Stmt *) stmt ); - Parent::previsit( stmt ); - } - - void LabelFinder::previsit( const ast::DeclStmt * stmt ) { - previsit( (const ast::Stmt *)stmt ); - Parent::previsit( stmt ); - } - - - void InsertDtors::previsit( const ast::FunctionDecl * funcDecl ) { - // each function needs to have its own set of labels - GuardValue( labelVars ); - labelVars.clear(); - // LabelFinder does not recurse into FunctionDecl, so need to visit - // its children manually. - if (funcDecl->type) funcDecl->type->accept(finder); - // maybeAccept( funcDecl->type, finder ); - if (funcDecl->stmts) funcDecl->stmts->accept(finder) ; - - // all labels for this function have been collected, insert destructors as appropriate via implicit recursion. - } - - // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the - // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope - // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user - // of the error. See C++ Reference 6.6 Jump Statements for details. - void InsertDtors::handleGoto( const ast::BranchStmt * stmt ) { - // can't do anything for computed goto - if ( stmt->computedTarget ) return; - - assertf( stmt->target.name != "", "BranchStmt missing a label: %s", toString( stmt ).c_str() ); - // S_L = lvars = set of objects in scope at label definition - // S_G = curVars = set of objects in scope at goto statement - ObjectSet & lvars = labelVars[ stmt->target ]; - - DTOR_PRINT( - std::cerr << "at goto label: " << stmt->target.name << std::endl; - std::cerr << "S_G = " << printSet( curVars ) << std::endl; - std::cerr << "S_L = " << printSet( lvars ) << std::endl; - ) - - - // std::set_difference requires that the inputs be sorted. - lvars.sort(); - curVars.sort(); - - ObjectSet diff; - // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty - std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) ); - DTOR_PRINT( - std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl; - ) - if ( ! diff.empty() ) { - SemanticError( stmt, std::string("jump to label '") + stmt->target.name + "' crosses initialization of " + (*diff.begin())->name + " " ); - } // if - } - - void InsertDtors::previsit( const ast::BranchStmt * stmt ) { - switch( stmt->kind ) { - case ast::BranchStmt::Continue: - case ast::BranchStmt::Break: - // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should - // always be empty), but it serves as a small sanity check. - case ast::BranchStmt::Goto: - handleGoto( stmt ); - break; - default: - assert( false ); - } // switch - } - - bool checkWarnings( const ast::FunctionDecl * funcDecl ) { - // only check for warnings if the current function is a user-defined - // constructor or destructor - if ( ! funcDecl ) return false; - if ( ! funcDecl->stmts ) return false; - return CodeGen::isCtorDtor( funcDecl->name ) && ! funcDecl->linkage.is_overrideable; - } - - void GenStructMemberCalls::previsit( const ast::FunctionDecl * funcDecl ) { - GuardValue( function ); - GuardValue( unhandled ); - GuardValue( usedUninit ); - GuardValue( thisParam ); - GuardValue( isCtor ); - GuardValue( structDecl ); - errors = SemanticErrorException(); // clear previous errors - - // need to start with fresh sets - unhandled.clear(); - usedUninit.clear(); - - function = mutate(funcDecl); - // could this be non-unique? - if (function != funcDecl) { - std::cerr << "GenStructMemberCalls: non-unique FunctionDecl " << funcDecl->location << funcDecl->name << std::endl; - } - - isCtor = CodeGen::isConstructor( function->name ); - if ( checkWarnings( function ) ) { - // const ast::FunctionType * type = function->type; - // assert( ! type->params.empty() ); - thisParam = function->params.front().strict_as(); - auto thisType = getPointerBase( thisParam->get_type() ); - auto structType = dynamic_cast< const ast::StructInstType * >( thisType ); - if ( structType ) { - structDecl = structType->base; - for ( auto & member : structDecl->members ) { - if ( auto field = member.as() ) { - // record all of the struct type's members that need to be constructed or - // destructed by the end of the function - unhandled.insert( field ); - } - } - } - } - } - - const ast::DeclWithType * GenStructMemberCalls::postvisit( const ast::FunctionDecl * funcDecl ) { - // remove the unhandled objects from usedUninit, because a call is inserted - // to handle them - only objects that are later constructed are used uninitialized. - std::map< const ast::DeclWithType *, CodeLocation > diff; - // need the comparator since usedUninit and unhandled have different types - struct comp_t { - typedef decltype(usedUninit)::value_type usedUninit_t; - typedef decltype(unhandled)::value_type unhandled_t; - bool operator()(usedUninit_t x, unhandled_t y) { return x.first < y; } - bool operator()(unhandled_t x, usedUninit_t y) { return x < y.first; } - } comp; - std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ), comp ); - for ( auto p : diff ) { - auto member = p.first; - auto loc = p.second; - // xxx - make error message better by also tracking the location that the object is constructed at? - emit( loc, "in ", function->name, ", field ", member->name, " used before being constructed" ); - } - - const CodeLocation loc = funcDecl->location; - - if ( ! unhandled.empty() ) { - auto mutStmts = function->stmts.get_and_mutate(); - // need to explicitly re-add function parameters to the indexer in order to resolve copy constructors - auto guard = makeFuncGuard( [this]() { symtab.enterScope(); }, [this]() { symtab.leaveScope(); } ); - symtab.addFunction( function ); - auto global = transUnit().global; - - // need to iterate through members in reverse in order for - // ctor/dtor statements to come out in the right order - for ( auto & member : reverseIterate( structDecl->members ) ) { - auto field = member.as(); - // skip non-DWT members - if ( ! field ) continue; - // skip non-constructable members - if ( ! tryConstruct( field ) ) continue; - // skip handled members - if ( ! unhandled.count( field ) ) continue; - - // insert and resolve default/copy constructor call for each field that's unhandled - // std::list< const ast::Stmt * > stmt; - ast::Expr * arg2 = nullptr; - if ( function->name == "?{}" && isCopyFunction( function ) ) { - // if copy ctor, need to pass second-param-of-this-function.field - // std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters(); - assert( function->params.size() == 2 ); - arg2 = new ast::MemberExpr(funcDecl->location, field, new ast::VariableExpr(funcDecl->location, function->params.back() ) ); - } - InitExpander_new srcParam( arg2 ); - // cast away reference type and construct field. - ast::Expr * thisExpr = new ast::CastExpr(funcDecl->location, new ast::VariableExpr(funcDecl->location, thisParam ), thisParam->get_type()->stripReferences()); - ast::Expr * memberDest = new ast::MemberExpr(funcDecl->location, field, thisExpr ); - ast::ptr callStmt = SymTab::genImplicitCall( srcParam, memberDest, loc, function->name, field, static_cast(isCtor) ); - - if ( callStmt ) { - // auto & callStmt = stmt.front(); - - try { - callStmt = callStmt->accept( *visitor ); - if ( isCtor ) { - mutStmts->push_front( callStmt ); - } else { // TODO: don't generate destructor function/object for intrinsic calls - // destructor statements should be added at the end - // function->get_statements()->push_back( callStmt ); - - // Optimization: do not need to call intrinsic destructors on members - if ( isIntrinsicSingleArgCallStmt( callStmt ) ) continue; - - // __Destructor _dtor0 = { (void *)&b.a1, (void (*)(void *)_destroy_A }; - std::list< ast::ptr > stmtsToAdd; - - static UniqueName memberDtorNamer = { "__memberDtor" }; - assertf( global.dtorStruct, "builtin __Destructor not found." ); - assertf( global.dtorDestroy, "builtin __destroy_Destructor not found." ); - - ast::Expr * thisExpr = new ast::CastExpr( new ast::AddressExpr( new ast::VariableExpr(loc, thisParam ) ), new ast::PointerType( new ast::VoidType(), ast::CV::Qualifiers() ) ); - ast::Expr * dtorExpr = new ast::VariableExpr(loc, getDtorFunc( thisParam, callStmt, stmtsToAdd ) ); - - // cast destructor pointer to void (*)(void *), to silence GCC incompatible pointer warnings - auto dtorFtype = new ast::FunctionType(); - dtorFtype->params.emplace_back( new ast::PointerType( new ast::VoidType() ) ); - auto dtorType = new ast::PointerType( dtorFtype ); - - auto destructor = new ast::ObjectDecl(loc, memberDtorNamer.newName(), new ast::StructInstType( global.dtorStruct ), new ast::ListInit(loc, { new ast::SingleInit(loc, thisExpr ), new ast::SingleInit(loc, new ast::CastExpr( dtorExpr, dtorType ) ) } ) ); - destructor->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr( loc, global.dtorDestroy ) } ) ); - mutStmts->push_front( new ast::DeclStmt(loc, destructor ) ); - mutStmts->kids.splice( mutStmts->kids.begin(), stmtsToAdd ); - } - } catch ( SemanticErrorException & error ) { - emit( funcDecl->location, "in ", function->name , ", field ", field->name, " not explicitly ", isCtor ? "constructed" : "destructed", " and no ", isCtor ? "default constructor" : "destructor", " found" ); - } - } - } - function->stmts = mutStmts; - } - if (! errors.isEmpty()) { - throw errors; - } - // return funcDecl; - return function; - } - - /// true if expr is effectively just the 'this' parameter - bool isThisExpression( const ast::Expr * expr, const ast::DeclWithType * thisParam ) { - // TODO: there are more complicated ways to pass 'this' to a constructor, e.g. &*, *&, etc. - if ( auto varExpr = dynamic_cast< const ast::VariableExpr * >( expr ) ) { - return varExpr->var == thisParam; - } else if ( auto castExpr = dynamic_cast< const ast::CastExpr * > ( expr ) ) { - return isThisExpression( castExpr->arg, thisParam ); - } - return false; - } - - /// returns a MemberExpr if expr is effectively just member access on the 'this' parameter, else nullptr - const ast::MemberExpr * isThisMemberExpr( const ast::Expr * expr, const ast::DeclWithType * thisParam ) { - if ( auto memberExpr = dynamic_cast< const ast::MemberExpr * >( expr ) ) { - if ( isThisExpression( memberExpr->aggregate, thisParam ) ) { - return memberExpr; - } - } else if ( auto castExpr = dynamic_cast< const ast::CastExpr * >( expr ) ) { - return isThisMemberExpr( castExpr->arg, thisParam ); - } - return nullptr; - } - - void GenStructMemberCalls::previsit( const ast::ApplicationExpr * appExpr ) { - if ( ! checkWarnings( function ) ) { - visit_children = false; - return; - } - - std::string fname = getFunctionName( appExpr ); - if ( fname == function->name ) { - // call to same kind of function - const ast::Expr * firstParam = appExpr->args.front(); - - if ( isThisExpression( firstParam, thisParam ) ) { - // if calling another constructor on thisParam, assume that function handles - // all members - if it doesn't a warning will appear in that function. - unhandled.clear(); - } else if ( auto memberExpr = isThisMemberExpr( firstParam, thisParam ) ) { - // if first parameter is a member expression on the this parameter, - // then remove the member from unhandled set. - if ( isThisExpression( memberExpr->aggregate, thisParam ) ) { - unhandled.erase( memberExpr->member ); - } - } - } - } - - void GenStructMemberCalls::previsit( const ast::MemberExpr * memberExpr ) { - if ( ! checkWarnings( function ) || ! isCtor ) { - visit_children = false; - return; - } - - if ( isThisExpression( memberExpr->aggregate, thisParam ) ) { - if ( unhandled.count( memberExpr->member ) ) { - // emit a warning because a member was used before it was constructed - usedUninit.insert( { memberExpr->member, memberExpr->location } ); - } - } - } - - template< typename... Params > - void GenStructMemberCalls::emit( CodeLocation loc, const Params &... params ) { - SemanticErrorException err( loc, toString( params... ) ); - errors.append( err ); - } - - const ast::Expr * GenStructMemberCalls::postvisit( const ast::UntypedExpr * untypedExpr ) { - // xxx - functions returning ast::ptr seems wrong... - auto res = ResolvExpr::findVoidExpression( untypedExpr, { symtab, transUnit().global } ); - return res.release(); - } - - void InsertImplicitCalls::previsit(const ast::UniqueExpr * unqExpr) { - if (visitedIds.count(unqExpr->id)) visit_children = false; - else visitedIds.insert(unqExpr->id); - } - - const ast::Expr * FixCtorExprs::postvisit( const ast::ConstructorExpr * ctorExpr ) { - const CodeLocation loc = ctorExpr->location; - static UniqueName tempNamer( "_tmp_ctor_expr" ); - // xxx - is the size check necessary? - assert( ctorExpr->result && ctorExpr->result->size() == 1 ); - - // xxx - this can be TupleAssignExpr now. Need to properly handle this case. - // take possession of expr and env - ast::ptr callExpr = ctorExpr->callExpr.strict_as(); - ast::ptr env = ctorExpr->env; - // ctorExpr->set_callExpr( nullptr ); - // ctorExpr->set_env( nullptr ); - - // xxx - ideally we would reuse the temporary generated from the copy constructor passes from within firstArg if it exists and not generate a temporary if it's unnecessary. - auto tmp = new ast::ObjectDecl(loc, tempNamer.newName(), callExpr->args.front()->result ); - declsToAddBefore.push_back( tmp ); - - // build assignment and replace constructor's first argument with new temporary - auto mutCallExpr = callExpr.get_and_mutate(); - const ast::Expr * firstArg = callExpr->args.front(); - ast::Expr * assign = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "?=?" ), { new ast::AddressExpr(loc, new ast::VariableExpr(loc, tmp ) ), new ast::AddressExpr( firstArg ) } ); - firstArg = new ast::VariableExpr(loc, tmp ); - mutCallExpr->args.front() = firstArg; - - // resolve assignment and dispose of new env - auto resolved = ResolvExpr::findVoidExpression( assign, { symtab, transUnit().global } ); - auto mut = resolved.get_and_mutate(); - assertf(resolved.get() == mut, "newly resolved expression must be unique"); - mut->env = nullptr; - - // for constructor expr: - // T x; - // x{}; - // results in: - // T x; - // T & tmp; - // &tmp = &x, ?{}(tmp), tmp - ast::CommaExpr * commaExpr = new ast::CommaExpr(loc, resolved, new ast::CommaExpr(loc, mutCallExpr, new ast::VariableExpr(loc, tmp ) ) ); - commaExpr->env = env; - return commaExpr; - } -} // namespace } // namespace InitTweak