381 lines
14 KiB
C++
381 lines
14 KiB
C++
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#include <cassert>
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include <utility>
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#include <vector>
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#include "cool-tree.h"
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#include "semant.h"
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#include "utilities.h"
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extern int semant_debug;
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extern char *curr_filename;
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//////////////////////////////////////////////////////////////////////
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//
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// Symbols
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//
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// For convenience, a large number of symbols are predefined here.
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// These symbols include the primitive type and method names, as well
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// as fixed names used by the runtime system.
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//
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//////////////////////////////////////////////////////////////////////
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static Symbol
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arg,
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arg2,
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Bool,
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concat,
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cool_abort,
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copy,
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Int,
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in_int,
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in_string,
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IO,
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length,
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Main,
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main_meth,
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No_class,
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No_type,
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Object,
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out_int,
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out_string,
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prim_slot,
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self,
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SELF_TYPE,
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Str,
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str_field,
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substr,
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type_name,
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val;
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//
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// Initializing the predefined symbols.
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//
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static void initialize_constants(void)
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{
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arg = idtable.add_string("arg");
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arg2 = idtable.add_string("arg2");
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Bool = idtable.add_string("Bool");
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concat = idtable.add_string("concat");
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cool_abort = idtable.add_string("abort");
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copy = idtable.add_string("copy");
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Int = idtable.add_string("Int");
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in_int = idtable.add_string("in_int");
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in_string = idtable.add_string("in_string");
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IO = idtable.add_string("IO");
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length = idtable.add_string("length");
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Main = idtable.add_string("Main");
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main_meth = idtable.add_string("main");
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// _no_class is a symbol that can't be the name of any
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// user-defined class.
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No_class = idtable.add_string("_no_class");
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No_type = idtable.add_string("_no_type");
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Object = idtable.add_string("Object");
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out_int = idtable.add_string("out_int");
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out_string = idtable.add_string("out_string");
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prim_slot = idtable.add_string("_prim_slot");
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self = idtable.add_string("self");
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SELF_TYPE = idtable.add_string("SELF_TYPE");
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Str = idtable.add_string("String");
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str_field = idtable.add_string("_str_field");
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substr = idtable.add_string("substr");
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type_name = idtable.add_string("type_name");
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val = idtable.add_string("_val");
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}
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/*
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* In ClassTable's constructor, the inheritance graph is built and checked,
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* with all defined classes recorded for later check.
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* In addition, scan attribute and method definition into global Symbol Table
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*/
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ClassTable::ClassTable(Classes classes) : semant_errors(0) , error_stream(cerr) {
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install_basic_classes();
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/* first scan: de-duplicate class definitions*/
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std::vector<class__class* > class_vec;
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for (auto i = classes->first(); classes->more(i); i = classes->next(i)) {
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auto class_i = static_cast<class__class*>(classes->nth(i));
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if (name_to_node.find(class_i->get_name()) != name_to_node.end()) {
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semant_error(class_i) << "Class " << class_i->get_name() << " was previously defined.\n";
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}
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else {
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// null means we have this class, but not yet build inheritence graph for it
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name_to_node[class_i->get_name()] = new ClassGraphNode(class_i, nullptr);
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// discard redefined classes by constructing a new vector of classes
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class_vec.push_back(class_i);
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}
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}
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/* second scan: check base class inheritable */
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auto sym_Bool = idtable.lookup_string("Bool");
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auto sym_Int = idtable.lookup_string("Int");
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auto sym_String = idtable.lookup_string("String");
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for (auto class_i : class_vec) {
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auto sym_parent = class_i->get_parent();
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// Cool has restrictions on inheriting from the basic classes
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if ( sym_parent == sym_Bool || sym_parent == sym_Int || sym_parent == sym_String) {
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semant_error(class_i) << "Class " << class_i->get_name()
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<< " cannot inherit class " << sym_parent << ".\n";
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}
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else if (name_to_node.find(sym_parent) == name_to_node.end()) {
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semant_error(class_i) << "Class `" << class_i->get_name() << "` inherits from an undefined class `"
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<< sym_parent << "`\n";
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}
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else {
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auto class_parent = name_to_node[sym_parent];
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// assert(class_parent != nullptr);
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class_parent->append_child(name_to_node[class_i->get_name()]);
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}
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}
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if (semant_errors) return;
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// we abort here before check cyclic inheritence if error once occurred
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// In COOL's case, every class could have only one base class
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// One simple judgement is that, if it cannot go up to object, then the class or its ancestor involves in a cycle
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// Thus, we can start from object and mark all reachable nodes, error report those unreachable nodes
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/* third scan: check cyclic inheritance */
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class_root->traverse();
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for (auto i : name_to_node) {
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if (!i.second->reachable()) {
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semant_error(i.second->get_class()) << "Class `" << i.first
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<< "` or its ancestor, is involved in an inheritance cycle.\n";
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}
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}
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if (semant_errors) return;
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if (semant_debug) {
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std::cerr<< "Class Inheritance Analysis done.\n";
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class_root->traverse(std::cout, 0);
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}
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/* fourth scan: gather attr and method definition */
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for (auto class_i : class_vec) {
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auto features_i = class_i->get_features();
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auto name_i = class_i->get_name();
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symtab_met[name_i] = new SymbolTable<Symbol, method_class>;
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symtab_obj[name_i] = new SymbolTable<Symbol, Entry>;
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symtab_met[name_i]->enterscope();
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symtab_obj[name_i]->enterscope();
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for (auto j = features_i->first(); features_i->more(j); j = features_i->next(j)) {
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auto feature_j = features_i->nth(j);
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if (typeid(*feature_j) == typeid(attr_class)) {
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auto attr_j = static_cast<attr_class*>(feature_j);
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symtab_obj[name_i]->addid(attr_j->get_name(), attr_j->get_type_decl());
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}
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else if (typeid(*feature_j) == typeid(method_class)) {
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auto method_j = static_cast<method_class*>(feature_j);
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symtab_met[name_i]->addid(method_j->get_name(), method_j);
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}
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else assert(0);
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}
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}
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if (semant_debug) {
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std::cerr << "Attr & Methods Collection done.\n";
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for (auto class_i : class_vec) {
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auto name_i = class_i->get_name();
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std::cerr << "M(" << name_i << ") =";
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symtab_met[name_i]->dump();
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std::cerr << "O(" << name_i << ") =";
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symtab_obj[name_i]->dump();
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std::cerr << "--------\n\n";
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}
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}
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}
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void ClassTable::install_basic_classes() {
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// The tree package uses these globals to annotate the classes built below.
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// curr_lineno = 0;
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Symbol filename = stringtable.add_string("<basic class>");
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// The following demonstrates how to create dummy parse trees to
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// refer to basic Cool classes. There's no need for method
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// bodies -- these are already built into the runtime system.
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// IMPORTANT: The results of the following expressions are
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// stored in local variables. You will want to do something
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// with those variables at the end of this method to make this
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// code meaningful.
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//
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// The Object class has no parent class. Its methods are
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// abort() : Object aborts the program
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// type_name() : Str returns a string representation of class name
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// copy() : SELF_TYPE returns a copy of the object
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//
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// There is no need for method bodies in the basic classes---these
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// are already built in to the runtime system.
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Class_ Object_class =
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class_(Object,
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No_class,
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append_Features(
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append_Features(
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single_Features(method(cool_abort, nil_Formals(), Object, no_expr())),
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single_Features(method(type_name, nil_Formals(), Str, no_expr()))),
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single_Features(method(copy, nil_Formals(), SELF_TYPE, no_expr()))),
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filename);
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//
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// The IO class inherits from Object. Its methods are
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// out_string(Str) : SELF_TYPE writes a string to the output
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// out_int(Int) : SELF_TYPE " an int " " "
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// in_string() : Str reads a string from the input
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// in_int() : Int " an int " " "
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//
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Class_ IO_class =
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class_(IO,
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Object,
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append_Features(
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append_Features(
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append_Features(
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single_Features(method(out_string, single_Formals(formal(arg, Str)),
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SELF_TYPE, no_expr())),
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single_Features(method(out_int, single_Formals(formal(arg, Int)),
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SELF_TYPE, no_expr()))),
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single_Features(method(in_string, nil_Formals(), Str, no_expr()))),
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single_Features(method(in_int, nil_Formals(), Int, no_expr()))),
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filename);
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//
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// The Int class has no methods and only a single attribute, the
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// "val" for the integer.
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//
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Class_ Int_class =
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class_(Int,
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Object,
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single_Features(attr(val, prim_slot, no_expr())),
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filename);
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//
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// Bool also has only the "val" slot.
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//
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Class_ Bool_class =
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class_(Bool, Object, single_Features(attr(val, prim_slot, no_expr())),filename);
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//
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// The class Str has a number of slots and operations:
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// val the length of the string
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// str_field the string itself
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// length() : Int returns length of the string
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// concat(arg: Str) : Str performs string concatenation
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// substr(arg: Int, arg2: Int): Str substring selection
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//
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Class_ Str_class =
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class_(Str,
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Object,
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append_Features(
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append_Features(
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append_Features(
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append_Features(
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single_Features(attr(val, Int, no_expr())),
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single_Features(attr(str_field, prim_slot, no_expr()))),
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single_Features(method(length, nil_Formals(), Int, no_expr()))),
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single_Features(method(concat,
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single_Formals(formal(arg, Str)),
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Str,
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no_expr()))),
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single_Features(method(substr,
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append_Formals(single_Formals(formal(arg, Int)),
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single_Formals(formal(arg2, Int))),
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Str,
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no_expr()))),
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filename);
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auto object_class = static_cast<class__class*>(Object_class);
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auto io_class = static_cast<class__class*>(IO_class);
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auto bool_class = static_cast<class__class*>(Bool_class);
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auto int_class = static_cast<class__class*>(Int_class);
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auto str_class = static_cast<class__class*>(Str_class);
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class_root = new ClassGraphNode(Object_class, nullptr);
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name_to_node[object_class->get_name()] = class_root;
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name_to_node[io_class->get_name()] = class_root->new_child(IO_class);
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name_to_node[int_class->get_name()] = class_root->new_child(Int_class);
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name_to_node[bool_class->get_name()] = class_root->new_child(Bool_class);
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name_to_node[str_class->get_name()] = class_root->new_child(Str_class);
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if (semant_debug) {
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std::cout << "Basic classed installed\n";
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class_root->traverse(std::cout, 0);
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}
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}
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////////////////////////////////////////////////////////////////////
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//
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// semant_error is an overloaded function for reporting errors
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// during semantic analysis. There are three versions:
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//
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// ostream& ClassTable::semant_error()
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//
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// ostream& ClassTable::semant_error(Class_ c)
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// print line number and filename for `c'
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//
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// ostream& ClassTable::semant_error(Symbol filename, tree_node *t)
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// print a line number and filename
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//
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///////////////////////////////////////////////////////////////////
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ostream& ClassTable::semant_error(Class_ c)
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{
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return semant_error(c->get_filename(),c);
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}
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ostream& ClassTable::semant_error(Symbol filename, tree_node *t)
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{
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error_stream << filename << ":" << t->get_line_number() << ": ";
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return semant_error();
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}
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ostream& ClassTable::semant_error()
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{
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semant_errors++;
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return error_stream;
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}
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/* This is the entry point to the semantic checker.
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Your checker should do the following two things:
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1) Check that the program is semantically correct
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2) Decorate the abstract syntax tree with type information
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by setting the `type' field in each Expression node.
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(see `tree.h')
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You are free to first do 1), make sure you catch all semantic
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errors. Part 2) can be done in a second stage, when you want
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to build mycoolc.
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*/
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void program_class::semant()
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{
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initialize_constants();
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/* ClassTable constructor may do some semantic analysis */
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ClassTable *classtable = new ClassTable(classes);
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/* Without confidence in inheritance consistency, abort before type checking*/
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if (classtable->errors()) {
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cerr << "Compilation halted due to static semantic errors." << endl;
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exit(1);
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}
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for (auto i = classes->first(); classes->more(i); i = classes->next(i)) {
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auto class_i = static_cast<class__class*>(classes->nth(i));
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class_i->semant();
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}
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/* some semantic analysis code may go here */
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if (classtable->errors()) {
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cerr << "Compilation halted due to static semantic errors." << endl;
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exit(1);
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}
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}
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void class__class::semant()
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{
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}
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