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// Copyright (c) Herb Sutter // SPDX-License-Identifier: CC-BY-NC-ND-4.0 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // THE SOFTWARE. //=========================================================================== // cppfront //=========================================================================== #include "sema.h" #include #include #include namespace cpp2 { // Defined out of line here just to avoid bringing into the headers, // so that we can't accidentally start depending on iostreams in the compiler body auto cmdline_processor::print(std::string_view s, int width) -> void { if (width > 0) { std::cout void { auto on_same_line = curr_pos.lineno == pos.lineno; // Ignoring this logic is used when we're generating new code sections, // such as return value structs, and emitting raw string literals if (ignore_align) { print( pad( ignore_align_indent - curr_pos.colno ) ); return; } // Otherwise, we need to apply our usual alignment logic // Catch up with displaying comments flush_comments( pos ); // If we're not on the right line if (printed_extra) { print_line_directive(pos.lineno); curr_pos.lineno = pos.lineno; printed_extra = false; } else if (curr_pos.lineno < pos.lineno) { // In case we're just one away, try a blank line // (this might get ignored and we'll get the line directive) print( "\n" ); if (curr_pos.lineno != pos.lineno) { print_line_directive(pos.lineno); } curr_pos.lineno = pos.lineno; } // Finally, align to the target column, if we're on the right line // and not one-past-the-end on the extra line at section end) assert( psource && 0 get_lines())+1 ); if ( curr_pos.lineno == pos.lineno && curr_pos.lineno < std::ssize(psource->get_lines()) ) { // Record this line's indentation as the 'last' line for next time last_line_indentation = psource->get_lines()[curr_pos.lineno].indent(); // If this line was originally densely spaced (had void { assert( is_open() && "ICE: printer must be open before printing" ); print( s, source_position{}, false ); printed_extra = true; } //----------------------------------------------------------------------- // Print a Cpp1 line, which should be at lineno // auto print_cpp1( std::string_view s, lineno_t line ) -> void { assert( is_open() && line >= 0 && "ICE: printer must be open before printing, and line number must not be negative (Cpp1 code is never generated)" ); // Always start a Cpp1 line on its own new line ensure_at_start_of_new_line(); // If we are out of sync with the current logical line number, // emit a #line directive to re-sync if (curr_pos.lineno != line) { print_line_directive( line ); curr_pos.lineno = line; } // Print the line assert (curr_pos.colno == 1); print( s ); print( "\n" ); } //----------------------------------------------------------------------- // Used when we start a new Cpp2 section, or when we emit the same item // more than once (notably when we emit operator= more than once) // auto reset_line_to(lineno_t line) -> void { // Always start a Cpp2 section on its own new line ensure_at_start_of_new_line(); // If we are out of sync with the current logical line number, // emit a #line directive to re-sync if (curr_pos.lineno != line) { print_line_directive( line ); curr_pos.lineno = line; } assert (curr_pos.colno == 1); } //----------------------------------------------------------------------- // Print a Cpp2 item, which should be at pos // auto print_cpp2( std::string_view s, source_position pos, bool leave_newlines_alone = false, bool is_known_empty = false ) -> void { // If we're printing for real (not to a string target) if (emit_target_stack.empty()) { // If we're in a generated text region (signified by negative // line numbers), then shunt this call to print_extra instead if (pos.lineno < 1) { if (generated_pos_line != pos.lineno) { *out void { inc_phase(); } // Provide an option to store to a given string instead, which is // useful for capturing Cpp1-formatted output for generated code // auto emit_to_string( std::string* target = {} ) -> void { if (target) { emit_string_targets.push_back( target ); emit_target_stack.push_back(target_type::string); } else { emit_string_targets.pop_back(); emit_target_stack.pop_back(); } } // Provide an option to store to a vector, which is // useful for postfix expression which have to mix unwrapping operators // with emitting sub-elements such as expression lists // auto emit_to_text_chunks( std::vector* target = {} ) -> void { if (target) { emit_text_chunks_targets.push_back( target ); emit_target_stack.push_back(target_type::chunks); } else { emit_text_chunks_targets.pop_back(); emit_target_stack.pop_back(); } } }; //----------------------------------------------------------------------- // // cppfront: a compiler instance // //----------------------------------------------------------------------- // struct function_prolog { std::vector mem_inits = {}; std::vector statements = {}; }; class cppfront { std::string sourcefile; std::vector errors; // For building // cpp2::source source; cpp2::tokens tokens; cpp2::parser parser; cpp2::sema sema; bool source_loaded = true; bool last_postfix_expr_was_pointer = false; bool violates_bounds_safety = false; bool violates_initialization_safety = false; bool suppress_move_from_last_use = false; declaration_node const* generating_assignment_from = {}; declaration_node const* generating_move_from = {}; bool emitting_that_function = false; bool emitting_move_that_function = false; std::vector already_moved_that_members = {}; struct arg_info { passing_style pass = passing_style::in; token const* ptoken = {}; }; std::vector current_args = { {} }; std::vector current_declarations = { {} }; // Maintain a stack of the functions we're currently processing, which can // be up to MaxNestedFunctions in progress (if we run out, bump the Max). // The main reason for this is to be able to pass function_info's, especially // their .epilog, by reference for performance while still having lifetime safety struct function_info { declaration_node const* decl = {}; declaration_node::declared_value_set_funcs declared_value_set_functions = {}; function_prolog prolog = {}; std::vector epilog = {}; function_info( declaration_node const* decl_, declaration_node::declared_value_set_funcs declared_value_set_functions_ ) : decl{decl_} , declared_value_set_functions{declared_value_set_functions_} { } }; class current_functions_ { std::deque list = { {} }; public: auto push( declaration_node const* decl, declaration_node::declared_value_set_funcs thats ) { list.emplace_back(decl, thats); } auto pop() { list.pop_back(); } auto back() -> function_info& { assert(!empty()); return list.back(); } auto empty() -> bool { return list.empty(); } }; current_functions_ current_functions; // For lowering // positional_printer printer; bool in_definite_init = false; bool in_parameter_list = false; std::string function_return_name; struct function_return { parameter_declaration_list_node* param_list; passing_style pass; bool is_deduced; function_return( parameter_declaration_list_node* param_list_, passing_style pass_ = passing_style::invalid, bool is_deduced_ = false ) : param_list{param_list_} , pass{pass_} , is_deduced{is_deduced_} { } }; std::vector function_returns; parameter_declaration_list_node single_anon; // special value - hack for now to note single-anon-return type kind in this function_returns working list std::vector function_requires_conditions; struct iter_info { iteration_statement_node const* stmt; bool used = false; }; std::vector iteration_statements; std::vector in_non_rvalue_context = { false }; std::vector need_expression_list_parens = { true }; auto push_need_expression_list_parens( bool b ) -> void { need_expression_list_parens.push_back(b); } auto pop_need_expression_list_parens() -> void { assert(std::ssize(need_expression_list_parens) > 1); need_expression_list_parens.pop_back(); } auto should_add_expression_list_parens() -> bool { assert(!need_expression_list_parens.empty()); return need_expression_list_parens.back(); } auto consumed_expression_list_parens() -> void { if( std::ssize(need_expression_list_parens) > 1 ) need_expression_list_parens.back() = false; } public: //----------------------------------------------------------------------- // Constructor // // filename the source file to be processed // cppfront(std::string const& filename) : sourcefile{ filename } , source { errors } , tokens { errors } , parser { errors } , sema { errors } { // "Constraints enable creativity in the right directions" // sort of applies here // if ( !sourcefile.ends_with(".cpp2") && !sourcefile.ends_with(".h2") ) { errors.emplace_back( source_position(-1, -1), "source filename must end with .cpp2 or .h2: " + sourcefile ); } // Load the program file into memory // else if (!source.load(sourcefile)) { if (errors.empty()) { errors.emplace_back( source_position(-1, -1), "file not found: " + sourcefile ); } source_loaded = false; } else { // Tokenize // tokens.lex(source.get_lines()); // Parse // try { for (auto const& [line, entry] : tokens.get_map()) { if (!parser.parse(entry, tokens.get_generated())) { errors.emplace_back( source_position(line, 0), "parse failed for section starting here", false, true // a noisy fallback error message ); } } // Sema parser.visit(sema); if (!sema.apply_local_rules()) { violates_initialization_safety = true; } } catch (std::runtime_error& e) { errors.emplace_back( source_position(-1, -1), e.what() ); } } } //----------------------------------------------------------------------- // lower_to_cpp1 // // Emits the target file with the last '2' stripped // struct lower_to_cpp1_ret { lineno_t cpp1_lines = 0; lineno_t cpp2_lines = 0; }; auto lower_to_cpp1() -> lower_to_cpp1_ret { auto ret = lower_to_cpp1_ret{}; // Only lower to Cpp1 if we haven't already encountered errors if (!errors.empty()) { return {}; } // Now we'll open the Cpp1 file auto cpp1_filename = sourcefile.substr(0, std::ssize(sourcefile) - 1); if (!flag_cpp1_filename.empty()) { cpp1_filename = flag_cpp1_filename; // use override if present } printer.open( sourcefile, cpp1_filename, tokens.get_comments(), source, parser ); if (!printer.is_open()) { errors.emplace_back( source_position{}, "could not open output file " + cpp1_filename ); return {}; } // Generate a reasonable macroized name auto cpp1_FILENAME = to_upper_and_underbar(cpp1_filename); //--------------------------------------------------------------------- // Do lowered file prolog // // Only emit extra lines if we actually have Cpp2, because // we want pure-Cpp1 files to pass through with zero changes if (source.has_cpp2()) { printer.print_extra( "\n" ); if (cpp1_filename.back() == 'h') { printer.print_extra( "#ifndef " + cpp1_FILENAME+"_CPP2\n"); printer.print_extra( "#define " + cpp1_FILENAME+"_CPP2" + "\n\n" ); } if (flag_use_source_location) { printer.print_extra( "#define CPP2_USE_SOURCE_LOCATION Yes\n" ); } if (flag_cpp2_only) { printer.print_extra( "#define CPP2_USE_MODULES Yes\n" ); } if (flag_no_exceptions) { printer.print_extra( "#define CPP2_NO_EXCEPTIONS Yes\n" ); } if (flag_no_rtti) { printer.print_extra( "#define CPP2_NO_RTTI Yes\n" ); } } auto map_iter = tokens.get_map().cbegin(); auto hpp_includes = std::string{}; //--------------------------------------------------------------------- // Do phase0_type_decls assert(printer.get_phase() == printer.phase0_type_decls); if ( source.has_cpp2() && !flag_clean_cpp1 ) { printer.print_extra( "\n//=== Cpp2 type declarations ====================================================\n\n" ); } if (!tokens.get_map().empty()) { printer.print_extra( "\n#include \"cpp2util.h\"\n\n" ); } for (auto& section : tokens.get_map()) { assert (!section.second.empty()); // Get the parse tree for this section and emit each forward declaration auto decls = parser.get_parse_tree_declarations_in_range(section.second); for (auto& decl : decls) { assert(decl); emit(*decl); } } //--------------------------------------------------------------------- // Do phase1_type_defs_func_decls // printer.finalize_phase(); printer.next_phase(); if ( source.has_cpp2() && !flag_clean_cpp1 ) { printer.print_extra( "\n//=== Cpp2 type definitions and function declarations ===========================\n\n" ); } assert (printer.get_phase() == positional_printer::phase1_type_defs_func_decls); for ( lineno_t curr_lineno = 0; auto const& line : source.get_lines() ) { // Skip dummy line we added to make 0-vs-1-based offsets readable if (curr_lineno != 0) { // If it's a Cpp1 line, emit it if (line.cat != source_line::category::cpp2) { if ( source.has_cpp2() && line.cat == source_line::category::empty ) { ++ret.cpp2_lines; } else { ++ret.cpp1_lines; } if ( flag_cpp2_only && !line.text.empty() && line.cat != source_line::category::comment && line.cat != source_line::category::import ) { if (line.cat == source_line::category::preprocessor) { if (!line.text.ends_with(".h2\"")) { errors.emplace_back( source_position(curr_lineno, 1), "pure-cpp2 switch disables the preprocessor, including #include (except of .h2 files) - use import instead (note: 'import std;' is implicit in -pure-cpp2)" ); return {}; } } else { errors.emplace_back( source_position(curr_lineno, 1), "pure-cpp2 switch disables Cpp1 syntax" ); return {}; } } if ( line.cat == source_line::category::preprocessor && line.text.ends_with(".h2\"") ) { // Strip off the 2" auto h_include = line.text.substr(0, line.text.size()-2); printer.print_cpp1( h_include + "\"", curr_lineno ); hpp_includes += h_include + "pp\"\n"; } else { printer.print_cpp1( line.text, curr_lineno ); } } // If it's a Cpp2 line... else { ++ret.cpp2_lines; // We should be in a position to emit a set of Cpp2 declarations if ( map_iter != tokens.get_map().cend() && map_iter->first /*line*/ std::string { auto print = std::string{}; print_to_string(&print, i, more...); return print; }; //----------------------------------------------------------------------- // try_emit // // Helper to emit whatever is in a variant where each // alternative is a smart pointer // template auto try_emit( auto& v, auto&&... more ) -> void { if (v.index() == I) { auto const& alt = std::get(v); assert (alt); emit (*alt, CPP2_FORWARD(more)...); } } //----------------------------------------------------------------------- // auto emit( token const& n, bool is_qualified = false, source_position pos = {} ) -> void { if (pos == source_position{}) { pos = n.position(); } // Implicit "cpp2::" qualification of Cpp2 fixed-width type aliases // and cpp2::finally if ( !is_qualified && ( n.type() == lexeme::Cpp2FixedType || n == "finally" ) ) { printer.print_cpp2("cpp2::", pos); } // 'this' is not a pointer if (n == "this") { printer.print_cpp2("(*this)", pos); } // Reclaim the alternative names and some keywords for users else if ( n == "and" || n == "and_eq" || n == "bitand" || n == "bitor" || n == "compl" || n == "not" || n == "not_eq" || n == "or" || n == "or_eq" || n == "xor" || n == "xor_eq" || n == "new" || n == "class" || n == "struct" || n == "enum" || n == "union" ) { printer.print_cpp2("cpp2_"+n.to_string(), pos); } else { printer.print_cpp2(n, pos, true); } in_definite_init = is_definite_initialization(&n); } //----------------------------------------------------------------------- // auto emit( literal_node const& n, source_position pos = {} ) -> void { if (pos == source_position{}) { pos = n.position(); } assert(n.literal); emit(*n.literal); if (n.user_defined_suffix) { emit(*n.user_defined_suffix); } } //----------------------------------------------------------------------- // auto emit( unqualified_id_node const& n, bool in_synthesized_multi_return = false, bool is_local_name = true, bool is_qualified = false ) -> void { auto last_use = is_definite_last_use(n.identifier); bool add_forward = last_use && last_use->is_forward && !in_non_rvalue_context.back(); bool add_move = !add_forward && ( in_synthesized_multi_return || (last_use && !suppress_move_from_last_use) ) && !in_non_rvalue_context.back(); if ( add_move && *(n.identifier - 1) == "return" && *(n.identifier + 1) == ";" ) { add_move = false; } if ( emitting_move_that_function && *n.identifier == "that" ) { add_move = true; } // For an explicit 'forward' apply forwarding to correct identifier assert (!current_args.empty()); if (current_args.back().pass == passing_style::forward) { add_forward = current_args.back().ptoken == n.identifier; } if (add_move) { printer.print_cpp2("std::move(", n.position()); } if (add_forward) { printer.print_cpp2("CPP2_FORWARD(", {n.position().lineno, n.position().colno - 8}); } assert(n.identifier); emit(*n.identifier, is_qualified); // inform the identifier if we know this is qualified if (n.open_angle != source_position{}) { printer.print_cpp2("", n.close_angle); } in_definite_init = is_definite_initialization(n.identifier); if ( !in_definite_init && !in_parameter_list ) { if (auto decl = sema.get_declaration_of(*n.identifier); is_local_name && !(*n.identifier == "this") && !(*n.identifier == "that") && decl && ( in_synthesized_multi_return // note pointer equality: if we're not in the actual declaration of n.identifier || decl->identifier != n.identifier ) // and this variable was uninitialized && !decl->initializer // and it's either a non-parameter or an out parameter && ( !decl->parameter || ( decl->parameter && decl->parameter->pass == passing_style::out ) ) ) { printer.print_cpp2(".value()", n.position()); } } else if (in_synthesized_multi_return) { printer.print_cpp2(".value()", n.position()); } if ( add_move || add_forward ) { printer.print_cpp2(")", n.position()); } } //----------------------------------------------------------------------- // auto emit(qualified_id_node const& n) -> void { if (!sema.check(n)) { return; } // Implicit "cpp2::" qualification of "unique.new" and "shared.new" if ( n.ids.size() == 2 && ( *n.ids[0].id->identifier == "unique" || *n.ids[0].id->identifier == "shared" ) && *n.ids[1].scope_op == "." && *n.ids[1].id->identifier == "new" ) { printer.print_cpp2("cpp2::", n.position()); } auto ident = std::string{}; printer.emit_to_string(&ident); for (auto const& id : n.ids) { if (id.scope_op) { emit(*id.scope_op); } emit(*id.id, false, true, true); // inform the unqualified-id that it's qualified } printer.emit_to_string(); printer.print_cpp2( ident, n.position() ); } //----------------------------------------------------------------------- // auto emit( type_id_node const& n, source_position pos = {} ) -> void { if (pos == source_position{}) { pos = n.position(); } if (n.is_wildcard()) { printer.print_cpp2("auto", pos); } else { try_emit(n.id, false, false); try_emit(n.id); try_emit(n.id); } for (auto i = n.pc_qualifiers.rbegin(); i != n.pc_qualifiers.rend(); ++i) { if ((**i) == "const") { printer.print_cpp2(" ", pos); } emit(**i, false, pos); } } //----------------------------------------------------------------------- // auto emit( id_expression_node const& n, bool is_local_name = true ) -> void { try_emit(n.id); try_emit(n.id, false, is_local_name); } auto emit_prolog_mem_inits( function_prolog const& prolog, colno_t indent ) -> void { for (auto& line : prolog.mem_inits) { printer.print_extra("\n"); printer.print_extra(pad(indent-1)); printer.print_extra(line); } } auto emit_prolog_statements( function_prolog const& prolog, colno_t indent ) -> void { for (auto& line : prolog.statements) { printer.print_extra("\n"); printer.print_extra(pad(indent-1)); printer.print_extra(line); } } auto emit_epilog_statements( std::vector const& epilog, colno_t indent ) -> void { for (auto& line : epilog) { printer.print_extra("\n"); printer.print_extra(pad(indent-1)); printer.print_extra(line); } } //----------------------------------------------------------------------- // auto emit( compound_statement_node const& n, function_prolog const& function_prolog = {}, std::vector const& function_epilog = {} ) -> void { emit_prolog_mem_inits(function_prolog, n.body_indent+1); printer.print_cpp2( "{", n.open_brace ); emit_prolog_statements(function_prolog, n.body_indent+1); for (auto const& x : n.statements) { assert(x); emit(*x); } emit_epilog_statements( function_epilog, n.body_indent+1); printer.print_cpp2( "}", n.close_brace ); } //----------------------------------------------------------------------- // auto emit( inspect_expression_node const& n, bool is_expression ) -> void { auto constexpr_qualifier = std::string{}; if (n.is_constexpr) { constexpr_qualifier = "constexpr "; } // If this is an expression, it will have an explicit result type, // and we need to start the lambda that we'll immediately invoke auto result_type = std::string{}; if (is_expression) { assert(n.result_type); printer.emit_to_string(&result_type); emit(*n.result_type); printer.emit_to_string(); printer.print_cpp2("[&] () -> " + result_type + " ", n.position()); } printer.print_cpp2("{ " + constexpr_qualifier + "auto&& _expr = ", n.position()); assert(n.expression); emit(*n.expression); printer.print_cpp2(";", n.position()); assert( n.identifier && *n.identifier == "inspect" ); assert(!n.alternatives.empty()); auto found_wildcard = false; for (auto first = true; auto&& alt : n.alternatives) { assert(alt && alt->is_as_keyword); if (!first) { printer.print_cpp2("else ", alt->position()); } first = false; auto id = std::string{}; printer.emit_to_string(&id); if (alt->type_id) { emit(*alt->type_id); } else { assert(alt->value); emit(*alt->value); } printer.emit_to_string(); assert ( *alt->is_as_keyword == "is" || *alt->is_as_keyword == "as" ); // TODO: pick up 'as' next, for now just do 'is' if (*alt->is_as_keyword == "is") { // Stringize the expression-statement now... auto statement = std::string{}; printer.emit_to_string(&statement); emit(*alt->statement); printer.emit_to_string(); // ... and jettison the final ; for an expression-statement while ( !statement.empty() && ( statement.back() == ';' || isspace(statement.back()) ) ) { statement.pop_back(); } replace_all( statement, "cpp2::as_("; suffix = ")" + suffix; } } // Else it's "is value", emit "cpp2::is(expr, value)" else { assert(i->expr); prefix += "cpp2::" + i->op->to_string() + "("; suffix = ", " + print_to_string(*i->expr) + ")" + suffix; } } if (as_on_literal) { auto last_pos = prefix.rfind('>'); assert(last_pos != prefix.npos); prefix.insert(last_pos, ", " + print_to_string(*n.expr)); } printer.print_cpp2(prefix, n.position()); if (wildcard_found) { printer.print_cpp2("true", n.position()); } else if(!as_on_literal) { emit(*n.expr); } printer.print_cpp2(suffix, n.position()); } //----------------------------------------------------------------------- // template< String Name, typename Term > auto emit(binary_expression_node const& n) -> void { assert(n.expr); assert( n.terms.empty() || n.terms.front().op ); // If this is relational comparison if ( !n.terms.empty() && ( n.terms.front().op->type() == lexeme::Less || n.terms.front().op->type() == lexeme::LessEq || n.terms.front().op->type() == lexeme::Greater || n.terms.front().op->type() == lexeme::GreaterEq || n.terms.front().op->type() == lexeme::EqualComparison || n.terms.front().op->type() == lexeme::NotEqualComparison ) ) { auto const& op = *n.terms.front().op; // If this is one (non-chained) comparison, just emit it directly if (std::ssize(n.terms) < 2) { assert (std::ssize(n.terms) == 1); // emit < = > as cmp_*(a,b) calls (if selected) if (flag_safe_comparisons) { switch (op.type()) { break;case lexeme::Less: printer.print_cpp2( "cpp2::cmp_less(", n.position()); break;case lexeme::LessEq: printer.print_cpp2( "cpp2::cmp_less_eq(", n.position()); break;case lexeme::Greater: printer.print_cpp2( "cpp2::cmp_greater(", n.position()); break;case lexeme::GreaterEq: printer.print_cpp2( "cpp2::cmp_greater_eq(", n.position()); break;default: ; } } emit(*n.expr); // emit == and != as infix a ? b operators (since we don't have // any checking/instrumentation we want to do for those) if (flag_safe_comparisons) { switch (op.type()) { break;case lexeme::EqualComparison: case lexeme::NotEqualComparison: printer.print_cpp2( " ", n.position() ); emit(op); printer.print_cpp2( " ", n.position() ); break;default: printer.print_cpp2( ",", n.position() ); } } else { emit(op); } emit(*n.terms.front().expr); if (flag_safe_comparisons) { switch (op.type()) { break;case lexeme::Less: case lexeme::LessEq: case lexeme::Greater: case lexeme::GreaterEq: printer.print_cpp2( ")", n.position() ); break;default: ; } } return; } // Else if this is a chained comparison, emit it as a lambda, // to get single evaluation via the lambda capture else { // To check for the valid chains: all =, or all == auto found_lt = 0; // < and and >= auto found_eq = 0; // == auto count = 0; auto const* lhs = n.expr.get(); auto lhs_name = "_" + std::to_string(count); auto lambda_capture = lhs_name + " = " + print_to_string(*lhs); auto lambda_body = std::string{}; for (auto const& term : n.terms) { assert( term.op && term.expr ); ++count; auto rhs_name = "_" + std::to_string(count); // Not the first expression? Insert a "&&" if (found_lt + found_gt + found_eq > 0) { lambda_body += " && "; } // Remember what we've seen switch (term.op->type()) { break;case lexeme::Less: case lexeme::LessEq: found_lt = 1; break;case lexeme::Greater: case lexeme::GreaterEq: found_gt = 1; break;case lexeme::EqualComparison: found_eq = 1; break;default: ; } // emit < = > as cmp_*(a,b) calls (if selected) if (flag_safe_comparisons) { switch (term.op->type()) { break;case lexeme::Less: lambda_body += "cpp2::cmp_less("; break;case lexeme::LessEq: lambda_body += "cpp2::cmp_less_eq("; break;case lexeme::Greater: lambda_body += "cpp2::cmp_greater("; break;case lexeme::GreaterEq: lambda_body += "cpp2::cmp_greater_eq("; break;default: ; } } auto rhs_expr = print_to_string(*term.expr); lambda_body += lhs_name; // emit == and != as infix a ? b operators (since we don't have // any checking/instrumentation we want to do for those) if (flag_safe_comparisons) { switch (term.op->type()) { break;case lexeme::EqualComparison: lambda_body += *term.op; break;case lexeme::NotEqualComparison: errors.emplace_back( n.position(), "!= comparisons cannot appear in a comparison chain (see https://wg21.link/p0893)" ); return; break;default: lambda_body += ","; } } else { lambda_body += *term.op; } lambda_capture += ", " + rhs_name + " = " + rhs_expr; lambda_body += rhs_name; lhs = term.expr.get(); lhs_name = rhs_name; if (flag_safe_comparisons) { switch (term.op->type()) { break;case lexeme::Less: case lexeme::LessEq: case lexeme::Greater: case lexeme::GreaterEq: lambda_body += ")"; break;default: ; } } } assert(found_lt + found_gt + found_eq > 0); if (found_lt + found_gt + found_eq != 1) { errors.emplace_back( n.position(), "a comparison chain must be all < and and >=, or all == (see https://wg21.link/p0893)" ); return; } printer.print_cpp2( "[" + lambda_capture + "]{ return " + lambda_body + "; }()", n.position()); return; } } // Else if this is an assignment expression, don't add std::move on the lhs // even if this is a definite last use (only do that when an rvalue is okay) if ( !n.terms.empty() && is_assignment_operator(n.terms.front().op->type()) ) { suppress_move_from_last_use = true; } // If it's "_ =" then emit static_cast() bool emit_discard = false; if ( !n.terms.empty() && n.terms.front().op->type() == lexeme::Assignment && n.expr->get_postfix_expression_node() && n.expr->get_postfix_expression_node()->get_first_token_ignoring_this() && *n.expr->get_postfix_expression_node()->get_first_token_ignoring_this() == "_" ) { printer.print_cpp2( "static_cast(", n.position() ); emit_discard = true; } else { emit(*n.expr); } suppress_move_from_last_use = false; // Check that this isn't an illegal pointer operation // (initial partial implementation) if ( !n.terms.empty() && last_postfix_expr_was_pointer ) { auto rhs_post = n.get_second_postfix_expression_node(); assert( rhs_post && rhs_post->expr ); auto rhs_tok = rhs_post->expr->get_token(); if ( is_assignment_operator(n.terms.front().op->type()) && rhs_tok && ( *rhs_tok == "nullptr" || is_digit((rhs_tok->as_string_view())[0]) ) ) { errors.emplace_back( n.terms.front().op->position(), n.terms.front().op->to_string() + " - pointer assignment from null or integer is illegal" ); violates_lifetime_safety = true; } else if ( *n.terms.front().op == "+" || *n.terms.front().op == "+=" || *n.terms.front().op == "-" || *n.terms.front().op == "-=" ) { errors.emplace_back( n.terms.front().op->position(), n.terms.front().op->to_string() + " - pointer arithmetic is illegal - use std::span or gsl::span instead" ); violates_bounds_safety = true; } } auto first = true; for (auto const& x : n.terms) { assert(x.op); assert(x.expr); // Normally we'll just emit the operator, but if this is an // assignment that's a definite initialization, change it to // a .construct() call if ( x.op->type() == lexeme::Assignment && in_definite_init ) { printer.print_cpp2( ".construct(", n.position() ); emit(*x.expr); printer.print_cpp2( ")", n.position() ); } else { // For the first operator only, if we are emitting a "_ =" discard // then we don't need the = if ( !emit_discard || !first ) { printer.print_cpp2(" ", n.position()); emit(*x.op); printer.print_cpp2(" ", n.position()); } // When assigning a single expression-list, we can // take over direct control of emitting it without needing to // go through the whole grammar, and surround it with braces if ( x.op->type() == lexeme::Assignment && x.expr->is_expression_list() ) { printer.print_cpp2( "{ ", n.position() ); emit(*x.expr->get_expression_list(), false); printer.print_cpp2( " }", n.position() ); } // Otherwise, just emit the general expression as usual else { emit(*x.expr); } } first = false; } // Finish emitting the "_ =" discard. if (emit_discard) { printer.print_cpp2( ")", n.position() ); } } //----------------------------------------------------------------------- // auto emit(expression_node const& n) -> void { assert(n.expr); push_need_expression_list_parens(true); emit(*n.expr); pop_need_expression_list_parens(); } //----------------------------------------------------------------------- // auto emit( expression_list_node const& n, bool parens_ok = true ) -> void { auto add_parens = should_add_expression_list_parens() && !n.inside_initializer && parens_ok ; add_parens |= n.is_fold_expression() && !(n.inside_initializer && current_declarations.back()->initializer->position() != n.open_paren->position()) ; if (add_parens) { printer.print_cpp2( *n.open_paren, n.position()); } auto first = true; for (auto const& x : n.expressions) { if (!first) { printer.print_cpp2(", ", n.position()); } first = false; auto is_out = false; if (x.pass != passing_style::in) { assert( x.pass == passing_style::out || x.pass == passing_style::move || x.pass == passing_style::forward ); if (x.pass == passing_style::out) { is_out = true; printer.print_cpp2("cpp2::out(&", n.position()); } else if (x.pass == passing_style::move) { printer.print_cpp2("std::move(", n.position()); } } if (is_out) { in_non_rvalue_context.push_back(true); } assert(x.expr); current_args.push_back( {x.pass} ); emit(*x.expr); current_args.pop_back(); if (is_out) { in_non_rvalue_context.pop_back(); } if ( x.pass == passing_style::move || x.pass == passing_style::out ) { printer.print_cpp2(")", n.position()); } } if (add_parens) { printer.print_cpp2( *n.close_paren, n.position()); } // We want to consume only one of these consumed_expression_list_parens(); } //----------------------------------------------------------------------- // auto emit( expression_statement_node const& n, bool can_have_semicolon, source_position function_body_start = {}, bool function_void_ret = false, function_prolog const& function_prolog = {}, std::vector const& function_epilog = {}, bool emitted = false ) -> void { assert(n.expr); auto generating_return = false; if (function_body_start != source_position{}) { emit_prolog_mem_inits(function_prolog, n.position().colno); printer.print_cpp2(" { ", function_body_start); emit_prolog_statements(function_prolog, n.position().colno); if (!function_void_ret) { printer.print_cpp2("return ", n.position()); generating_return = true; } } if (!emitted) { // When generating 'return' of a single expression-list, we can // take over direct control of emitting it without needing to // go through the whole grammar, and surround it with braces if ( generating_return && n.expr->is_expression_list() && !n.expr->get_expression_list()->is_fold_expression() ) { auto is_deduced_return = !function_returns.empty() && function_returns.back().is_deduced; if (!is_deduced_return) { printer.print_cpp2( "{ ", n.position() ); } emit(*n.expr->get_expression_list(), false); if (!is_deduced_return) { printer.print_cpp2( " }", n.position() ); } } // Otherwise, just emit the general expression as usual else { emit(*n.expr); } if (can_have_semicolon) { printer.print_cpp2(";", n.position()); } } if (function_body_start != source_position{}) { emit_epilog_statements( function_epilog, n.position().colno); printer.print_cpp2(" }", n.position()); } } //----------------------------------------------------------------------- // auto emit( statement_node const& n, bool can_have_semicolon = true, source_position function_body_start = {}, bool function_void_ret = false, function_prolog const& function_prolog = {}, std::vector const& function_epilog = {} ) -> void { if (!sema.check(n)) { return; } auto emit_parameters = !n.emitted && n.parameters ; if (emit_parameters) { printer.print_extra( "\n"); printer.print_extra( "{"); for (auto& param : n.parameters->parameters) { printer.print_extra( "\n"); printer.print_extra( print_to_string(*param) ); } } // Do expression statement case first... it's the most complex // because it's used for single-statement function bodies try_emit( n.statement, can_have_semicolon, function_body_start, function_void_ret, function_prolog, function_epilog, n.emitted ); // Otherwise, skip this one if it was already handled earlier (i.e., a constructor member init) if (n.emitted) { return; } printer.disable_indent_heuristic_for_next_text(); try_emit(n.statement, function_prolog, function_epilog); // NOTE: Reset preemption here because // - for compound statements written as "= { ... }", we want to keep the // preempted position which moves the { to where the = was // - but for other statement types, we want to get rid of any leftover // preemption (ideally there wouldn't be any, but sometimes there is // and it should not apply to what we're about to emit) printer.preempt_position_push({}); // This only has a whitespace effect in the generated Cpp1 code, but it's // aesthetic and aesthetics are important in this case -- we want to keep // the original source's personal whitespace formatting style as much as we can try_emit(n.statement); try_emit(n.statement); try_emit(n.statement); try_emit(n.statement); try_emit(n.statement); try_emit(n.statement, false); try_emit(n.statement); printer.preempt_position_pop(); if (emit_parameters) { printer.print_extra( "\n"); printer.print_extra( "}"); } } //----------------------------------------------------------------------- // Within a type scope implementation, disallow declaring a name that // is the same as (i.e., shadows) a type scope name... this is a // convenient place to check because we have the decls stack // auto check_shadowing_of_type_scope_names( declaration_node const& decl ) -> bool { if ( decl.has_name() // this is a named declaration && !decl.has_name("this") // that's not 'this' && !decl.parent_is_type() // and the type isn't the direct parent && is_name_declared_in_current_type_scope(*decl.name()) ) // and it shadows a name { errors.emplace_back( decl.position(), "a type's implementation may not declare a name that is the same as (i.e., shadows) a type scope name - for example, a type scope function's local variable may not have the same as one of the type's members" ); return false; } return true; } //----------------------------------------------------------------------- // auto emit( parameter_declaration_node const& n, bool is_returns = false, bool is_template_parameter = false ) -> void { // Can't declare functions as parameters -- only pointers to functions which are objects assert( n.declaration ); assert( !n.declaration->is_function() ); if (!check_shadowing_of_type_scope_names(*n.declaration)) { return; } if (n.mod == parameter_declaration_node::modifier::implicit) { assert(!current_functions.empty()); if ( n.pass != passing_style::out || !current_functions.back().decl->has_name("operator=") ) { errors.emplace_back( n.position(), "only an 'out this' parameter of an 'operator=' function may be declared implicit" ); } } //----------------------------------------------------------------------- // Skip 'this' parameters if (n.declaration->has_name("this")) { // Since we're skipping "out this," plus possibly "implicit " and // whitespace, any following parameters on the same line can shift left printer.add_pad_in_this_line(-18); return; } //----------------------------------------------------------------------- // Handle 'that' parameters if (n.declaration->has_name("that")) { emitting_that_function = true; assert( n.pass == passing_style::in || n.pass == passing_style::move ); auto pass = std::string{" const&"}; if ( n.pass == passing_style::move || emitting_move_that_function ) { pass = "&&"; } auto func_name = get_enclosing_function_name(); assert(func_name); auto type_name = get_enclosing_type_name(); assert(type_name); // If we're in an empty type that has no member object, mark 'that' as // [[maybe_unused]] to silence Cpp1 compiler warnings assert(!current_functions.empty()); auto maybe_unused = std::string{}; if (current_functions.back().decl->get_parent()->get_type_scope_declarations(declaration_node::objects).empty()) { maybe_unused = "[[maybe_unused]] "; } printer.print_cpp2( maybe_unused + print_to_string( *type_name ) + pass + " that", n.position() ); return; } //----------------------------------------------------------------------- // Handle type parameters if (n.declaration->is_type()) { printer.print_cpp2("typename ", n.declaration->identifier->position()); if (n.declaration->is_variadic) { printer.print_cpp2( "...", n.declaration->identifier->position() ); } assert (n.declaration->identifier); emit(*n.declaration->identifier); return; } //----------------------------------------------------------------------- // Else handle template non-type parameters assert( n.declaration->is_object() ); auto const& type_id = *std::get(n.declaration->type); if (is_template_parameter) { emit( type_id ); printer.print_cpp2(" ", type_id.position()); assert (n.declaration->identifier); emit(*n.declaration->identifier); return; } //----------------------------------------------------------------------- // Else handle ordinary parameters auto param_type = print_to_string(type_id); // If there are template parameters on this function or its enclosing // type, see if this parameter's name is an unqualified-id with a // template parameter name, or mentions a template parameter as a // template argument auto has_template_parameter_type_named = []( declaration_node const& decl, std::string_view name ) -> bool { if (decl.template_parameters) { for (auto& tparam : decl.template_parameters->parameters) { assert( tparam && tparam->name() ); // For now just do a quick string match auto tparam_name = tparam->name()->to_string(); if ( tparam->declaration->is_type() && ( name == tparam_name || name.find("", n.position() ); break;case passing_style::copy : printer.print_cpp2( "", n.position() ); break;case passing_style::inout : printer.print_cpp2( "&", n.position() ); break;case passing_style::out : printer.print_cpp2( ">", n.position() ); break;case passing_style::move : printer.print_cpp2( "&&", n.position() ); break;case passing_style::forward: printer.print_cpp2( "&&", n.position() ); break;default: ; } } if (is_returns) { printer.print_extra( " " + identifier); } else { printer.print_cpp2( " ", n.declaration->identifier->position()); if (n.declaration->is_variadic) { if (n.direction() == passing_style::out) { errors.emplace_back( n.declaration->position(), "a variadic parameter cannot be 'out'" ); return; } printer.print_cpp2( "...", n.declaration->identifier->position() ); } printer.print_cpp2( identifier, n.declaration->identifier->position()); } if ( !is_returns && n.declaration->initializer ) { printer.print_cpp2( " = ", n.declaration->initializer->position() ); emit(*n.declaration->initializer); } } //----------------------------------------------------------------------- // auto emit( parameter_declaration_list_node const& n, bool is_returns = false, bool is_template_parameter = false ) -> void { in_parameter_list = true; if (is_returns) { printer.print_extra( "{ " ); } else { assert(n.open_paren); emit(*n.open_paren); } // So we don't get cute about text-aligning the first parameter when it's on a new line printer.disable_indent_heuristic_for_next_text(); auto prev_pos = n.position(); for (auto first = true; auto const& x : n.parameters) { if ( !first && !is_returns ) { printer.print_cpp2( ", ", prev_pos ); } prev_pos = x->position(); assert(x); emit(*x, is_returns, is_template_parameter); if (!x->declaration->has_name("this")) { first = false; } if (is_returns) { printer.print_extra( "; " ); } } if (is_returns) { printer.print_extra( "};\n" ); } else { // Position heuristic (aka hack): Avoid emitting extra whitespace before ) // beyond column 10 assert(n.close_paren); auto col = std::min( n.close_paren->position().colno, colno_t{10}); printer.preempt_position_push({ n.close_paren->position().lineno, col}); emit(*n.close_paren); printer.preempt_position_pop(); } in_parameter_list = false; } //----------------------------------------------------------------------- // auto emit( // note: parameter is deliberately not const because we will fill // in the capture .str information contract_node& n ) -> void { assert (n.kind); // For a postcondition, we'll wrap it in a final_action_success lambda // if (*n.kind == "post") { auto lambda_intro = build_capture_lambda_intro_for(n.captures, n.position()); printer.print_cpp2( "auto post_" + std::to_string(n.position().lineno) + "_" + std::to_string(n.position().colno) + " = cpp2::finally_success(" + lambda_intro + "{", n.position() ); } // Emit the contract group name (defaults to cpp2::Default) // if (n.group) { // If this is one of Cpp2's predefined contract groups, // make it convenient to use without cpp2:: qualification if (auto uid = std::get_if(&n.group->id)) { assert (*uid && (**uid).identifier); if ( *(**uid).identifier == "Default" || *(**uid).identifier == "Bounds" || *(**uid).identifier == "Null" || *(**uid).identifier == "Type" || *(**uid).identifier == "Testing" ) { printer.print_cpp2("cpp2::", n.position()); } } printer.preempt_position_push(n.position()); printer.add_pad_in_this_line(-20); emit(*n.group); printer.preempt_position_pop(); } else { printer.print_cpp2("cpp2::Default", n.position()); printer.add_pad_in_this_line(-8); } // And invoke .expects on that contract group // printer.print_cpp2(".expects(", n.position()); assert(n.condition); emit (*n.condition); printer.print_cpp2(", ", n.position()); if (n.message) { emit (*n.message); } else { printer.print_cpp2("\"\"", n.position()); } printer.print_cpp2(");", n.position()); // For a postcondition, close out the final_action_success lambda // if (*n.kind == "post") { printer.print_cpp2( "} );", n.position() ); } } //----------------------------------------------------------------------- // auto emit( function_type_node const& n, token const* ident, bool is_main = false, bool is_ctor_or_dtor = false, std::string suffix1 = {} ) -> void { assert(n.parameters); if ( is_main && n.parameters->parameters.size() > 0 ) { printer.print_cpp2( "(int const argc_, char** argv_)", n.parameters->position() ); current_functions.back().prolog.statements.push_back( "auto args = cpp2::make_args(argc_, argv_); " ); } else { emit(*n.parameters); } // For now, adding implicit noexcept only for move/swap/dtor functions if ( n.is_move() || n.is_swap() || n.is_destructor() || generating_move_from == n.my_decl ) { printer.print_cpp2( " noexcept", n.position() ); } printer.print_cpp2( suffix1, n.position() ); // Handle a special member function if ( n.is_assignment() || generating_assignment_from == n.my_decl ) { assert( n.returns.index() == function_type_node::empty && n.my_decl->parent_declaration->name() ); printer.print_cpp2( " -> " + print_to_string( *n.my_decl->parent_declaration->name() ) + "& ", n.position() ); } // Otherwise, handle a default return type else if (n.returns.index() == function_type_node::empty) { if (is_main) { printer.print_cpp2( " -> int", n.position() ); } else if(!is_ctor_or_dtor) { printer.print_cpp2( " -> void", n.position() ); } } // Otherwise, handle a single anonymous return type else if (n.returns.index() == function_type_node::id) { auto is_type_scope_function_with_in_this = n.my_decl->parent_is_type() && n.parameters->ssize() > 0 && (*n.parameters)[0]->direction() == passing_style::in ; printer.print_cpp2( " -> ", n.position() ); auto& r = std::get(n.returns); assert(r.type); auto return_type = print_to_string(*r.type); if (r.pass == passing_style::forward) { if (r.type->is_wildcard()) { printer.print_cpp2( "auto&&", n.position() ); } else { printer.print_cpp2( return_type, n.position() ); if (is_type_scope_function_with_in_this) { printer.print_cpp2( " const&", n.position() ); } else { printer.print_cpp2( "&", n.position() ); } } } else { printer.print_cpp2( return_type, n.position() ); } } // Otherwise, handle multiple/named returns else { printer.print_cpp2( " -> ", n.position() ); function_return_name = {}; printer.emit_to_string(&function_return_name); assert(ident); printer.print_cpp2( *ident, ident->position() ); printer.print_cpp2( "_ret", ident->position() ); printer.emit_to_string(); printer.print_cpp2( function_return_name, ident->position() ); } } //----------------------------------------------------------------------- // auto is_name_declared_in_current_type_scope(std::string_view s) -> bool { if (!s.empty()) { // Navigate to the enclosing type, if there is one... for (auto parent = current_declarations.rbegin(); parent != current_declarations.rend(); ++parent ) { if ( *parent && (*parent)->is_namespace() ) { break; } // ... and here it is, so... if ( *parent && (*parent)->is_type() ) { // ... for each of its type scope decls... for (auto const& decl : (*parent)->get_type_scope_declarations()) { // ... check the name if (decl->has_name(s)) { return true; } } break; } } } return false; } //----------------------------------------------------------------------- // auto get_enclosing_type_name() -> token const* { // Navigate to the enclosing type, if there is one... for (auto parent = current_declarations.rbegin(); parent != current_declarations.rend(); ++parent ) { if ( *parent && (*parent)->is_namespace() ) { break; } // ... and here it is, so... if ( *parent && (*parent)->is_type() ) { return (*parent)->name(); } } return {}; } //----------------------------------------------------------------------- // auto get_enclosing_function_name() -> token const* { // Navigate to the enclosing function, if there is one... for (auto parent = current_declarations.rbegin(); parent != current_declarations.rend(); ++parent ) { if ( *parent && (*parent)->is_namespace() ) { break; } // ... and here it is, so... if ( *parent && (*parent)->is_function() ) { return (*parent)->name(); } } return {}; } //----------------------------------------------------------------------- // Helper to emit type-qualified names for member functions // auto type_qualification_if_any_for( declaration_node const& n ) -> std::string { auto ret = std::string{}; if ( printer.get_phase() == printer.phase2_func_defs && n.parent_is_type() // && !n.name()->as_string_view().starts_with("operator") ) { // If this function is inside templated type(s), // emit those outer template parameter lists too auto parent = n.parent_declaration; while ( parent && parent->is_type() ) { auto list = std::string{""}; if (parent->template_parameters) { auto separator = std::string{""; } ret = print_to_string(*parent->identifier) + list + "::" + ret; parent = parent->parent_declaration; } } return ret; } //----------------------------------------------------------------------- // Constructors and assignment operators // auto emit_special_member_function( declaration_node const& n, std::string prefix ) -> void { assert(n.is_function()); auto& func = std::get(n.type); assert(func); auto is_assignment = generating_assignment_from == &n || (*func->parameters)[0]->pass == passing_style::inout; if ( func->parameters->ssize() > 1 && (*func->parameters)[1]->has_name("that") ) { emitting_that_function = true; if ( (*func->parameters)[1]->pass == passing_style::move || generating_move_from == &n ) { emitting_move_that_function = true; } } // Do the 'out' param and member init work only in the definition phase if (printer.get_phase() == printer.phase2_func_defs) { auto canonize_object_name = [&]( declaration_node const* obj ) -> std::string { assert(obj->has_name()); auto ret = obj->name()->to_string(); if (ret == "this") { ret = print_to_string( *obj->get_object_type() ); } return ret; }; // We'll use this common guidance in several errors, // so write it once to keep the guidance consistent assert (n.parent_declaration && n.parent_declaration->name()); auto error_msg = "an operator= body must start with a series of 'member = value;' initialization statements for each of the type-scope objects in the same order they are declared, or the member must have a default initializer (in type '" + n.parent_declaration->name()->to_string() + "')"; // If this constructor's type has data members, handle their initialization // - objects is the list of this type's declarations // - statements is the list of this constructor's statements auto objects = n.parent_declaration->get_type_scope_declarations(n.objects); auto statements = n.get_initializer_statements(); auto out_inits = std::vector{}; auto object = objects.begin(); auto statement = statements.begin(); auto separator = std::string{": "}; while (object != objects.end()) { auto object_name = canonize_object_name(*object); auto is_object_before_base = n.get_decl_if_type_scope_object_name_before_a_base_type(*(*object)->name()); auto found_explicit_init = false; auto found_default_init = false; auto stmt_pos = n.position(); auto initializer = std::string{}; // If we're at an assignment statement, get the lhs and rhs if (statement != statements.end()) { assert (*statement); stmt_pos = (*statement)->position(); if (stmt_pos.lineno < 0) { stmt_pos = n.position(); } auto lhs = std::string{}; auto rhs = std::string{}; { auto exprs = (*statement)->get_lhs_rhs_if_simple_assignment(); if (exprs.lhs) { if (auto tok = exprs.lhs->get_first_token_ignoring_this()) { lhs = *tok; } else { lhs = print_to_string( *exprs.lhs ); } } if (exprs.rhs) { rhs = print_to_string( *exprs.rhs ); } } // If this is an initialization of an 'out' parameter, stash it if (n.has_out_parameter_named(lhs)){ out_inits.push_back( print_to_string(**statement, false) ); (*statement)->emitted = true; ++statement; continue; } // Now we're ready to check whether this is an assignment to *object if (!lhs.empty()) { // First, see if it's an assignment 'name = something' found_explicit_init = object_name == lhs; // Otherwise, see if it's 'this.name = something' if (!found_explicit_init) { // If it's of the form 'this.name', check 'name' if ( starts_with( lhs, "(*this).") && object_name == lhs.substr(8) ) { found_explicit_init = true; } } if (found_explicit_init) { initializer = rhs; // We've used this statement, so note it // and move 'statement' forward (*statement)->emitted = true; ++statement; } } } // Otherwise, use a default... for a non-copy/move that's the member initializer // (for which we don't need to emit anything special because it will get used), // and for a copy/move function we default to "= that.same_member" (or, if this // is a base type, to assigning from the lowered base subobject) if (!found_explicit_init) { if (emitting_that_function && (*object)->has_name("this")) { auto pass = std::string{" const&"}; if (emitting_move_that_function) { pass = "&&"; } initializer = "static_cast(that)"; found_default_init = true; } else if (emitting_move_that_function) { initializer = "std::move(that)." + object_name; found_default_init = true; } else if (emitting_that_function) { initializer = "that." + object_name; found_default_init = true; } else if ((*object)->initializer) { initializer = print_to_string(*(*object)->initializer, false); found_default_init = true; } } // If this is not an assignment to *object, // and there was no member initializer, complain if ( !found_explicit_init && !found_default_init ) { errors.emplace_back( stmt_pos, "in operator=, expected '" + object_name + " = ...' initialization statement (because type scope object '" + object_name + "' does not have a default initializer)" ); errors.emplace_back( (*object)->position(), "see declaration for '" + object_name + "' here" ); errors.emplace_back( stmt_pos, error_msg ); return; } assert( found_explicit_init || found_default_init ); // Emit the initializer... if (initializer.empty()) { initializer = "{}"; } // (a) ... if this is assignment, emit it in all cases if (is_assignment) { assert ((*object)->name()); // Flush any 'out' parameter initializations for (auto& init : out_inits) { current_functions.back().prolog.statements.push_back(init + ";"); } out_inits = {}; // Then add this statement // Use ::operator= for base classes if ((*object)->has_name("this")) { current_functions.back().prolog.statements.push_back( print_to_string( *(*object)->get_object_type() ) + "::operator= ( " + initializer + " );" ); } // Else just use infix assignment else { current_functions.back().prolog.statements.push_back( object_name + " = " + initializer + ";" ); } } // (b) ... if this isn't assignment, only need to emit it if it was // explicit, or is a base type or 'that' initializer else if ( found_explicit_init || is_object_before_base || ( (*object)->has_name("this") && !initializer.empty() ) || emitting_that_function ) { if (is_object_before_base) { assert (is_object_before_base->name()); object_name = print_to_string( *is_object_before_base->parent_declaration->name() ) + "_" + (*object)->name()->to_string() + "_as_base"; } // Flush any 'out' parameter initializations auto out_inits_with_commas = [&]() -> std::string { auto ret = std::string{}; for (auto& init : out_inits) { ret += init + ", "; } out_inits = {}; return ret; }(); // If there were any, wedge them into this initializer // using (holds nose) the comma operator and extra parens // as we add this statement if (!out_inits_with_commas.empty()) { current_functions.back().prolog.mem_inits.push_back( separator + object_name + "{(" + out_inits_with_commas + initializer + " )}" ); } else { if (initializer == "{}") { initializer = ""; } current_functions.back().prolog.mem_inits.push_back( separator + object_name + "{ " + initializer + " }" ); } separator = ", "; } // And on to the next data member... ++object; } // Now no data members should be left over if (object != objects.end()) { errors.emplace_back( (*object)->position(), canonize_object_name(*object) + " was not initialized - did you forget to write a default initializer, or assign to it in the operator= body?" ); errors.emplace_back( (*object)->position(), "see declaration for '" + canonize_object_name(*object) + "' here" ); errors.emplace_back( (*object)->position(), error_msg ); return; } // Flush any possible remaining 'out' parameters for (auto& init : out_inits) { current_functions.back().prolog.statements.push_back(init + ";"); } } // For a constructor, print the type name instead of the operator= function name assert(n.parent_is_type()); if (!is_assignment) { printer.print_cpp2( prefix, n.position() ); printer.print_cpp2( type_qualification_if_any_for(n), n.position() ); printer.print_cpp2( print_to_string( *n.parent_declaration->name() ), n.position() ); emit( *func, n.name(), false, true ); } // For an assignment operator, similar to emitting an ordinary function else { assert (!current_functions.empty()); current_functions.back().epilog.push_back( "return *this;"); printer.print_cpp2( prefix, n.position() ); printer.print_cpp2( "auto " + type_qualification_if_any_for(n) + print_to_string( *n.name() ), n.position()); emit( *func, n.name() ); } } //----------------------------------------------------------------------- // auto emit( declaration_node const& n, std::string const& capture_intro = {} ) -> void { // Helper for declarations that can have requires-clauses auto const emit_requires_clause = [&]() { if ( n.requires_clause_expression || !function_requires_conditions.empty() ) { printer.print_extra("\n"); printer.ignore_alignment( true, n.position().colno + 4 ); if (printer.get_phase() == printer.phase1_type_defs_func_decls) { // Workaround GCC 10 not supporting requires in forward declarations in some cases. // See commit 5a0d77f8e297902c0b9712c5aafb6208cfa4c139. if (n.is_object() || n.parent_is_type()) { printer.print_extra("CPP2_REQUIRES_ ("); } else { printer.print_extra("CPP2_REQUIRES ("); } } else { printer.print_extra("requires ("); } if (n.requires_clause_expression) { emit(*n.requires_clause_expression); if (!function_requires_conditions.empty()) { printer.print_extra(" && "); } } if (!function_requires_conditions.empty()) { printer.print_extra(function_requires_conditions.front()); for (auto it = std::cbegin(function_requires_conditions)+1; it != std::cend(function_requires_conditions); ++it) { printer.print_extra(" && " + *it); } } printer.print_extra(")"); function_requires_conditions = {}; printer.ignore_alignment( false ); } }; // Declarations are handled in multiple passes, // but we only want to do the sema checks once if ( printer.get_phase() == printer.phase2_func_defs && !sema.check(n) ) { return; } // In phase 0, only need to consider namespaces and types if ( printer.get_phase() == printer.phase0_type_decls && !n.is_namespace() && !n.is_type() ) { return; } // If this is a generated declaration (negative source line number), // add a line break before if ( printer.get_phase() == printer.phase2_func_defs && n.position().lineno < 1 ) { printer.print_extra("\n"); } // Handle aliases if (n.is_alias()) { auto& a = std::get(n.type); assert(a); // Namespace-scope aliases are emitted in phase 1, // type-scope object aliases in both phases 1 and 2, and // function-scope aliases in phase 2 if ( ( !n.parent_is_function() && printer.get_phase() == printer.phase1_type_defs_func_decls ) || ( n.parent_is_type() && n.is_object_alias() && printer.get_phase() == printer.phase2_func_defs ) || ( n.parent_is_function() && printer.get_phase() == printer.phase2_func_defs ) ) { assert( a->is_type_alias() || a->is_namespace_alias() || a->is_object_alias() ); // If we're in a type scope, handle the access specifier if ( n.parent_is_type() && printer.get_phase() == printer.phase1_type_defs_func_decls ) { if (!n.is_default_access()) { printer.print_cpp2(to_string(n.access) + ": ", n.position()); } else { printer.print_cpp2("public: ", n.position()); } } // Emit template parameters if any if (n.template_parameters) { printer.print_cpp2("template", n.position()); emit(*n.template_parameters, false, true); printer.print_cpp2(" ", n.position()); } // Emit requires clause if any emit_requires_clause(); // Handle type aliases if (a->is_type_alias()) { printer.print_cpp2( "using " + print_to_string(*n.identifier) + " = " + print_to_string( *std::get(a->initializer) ) + ";\n", n.position() ); } // Handle namespace aliases else if (a->is_namespace_alias()) { printer.print_cpp2( "namespace " + print_to_string(*n.identifier) + " = " + print_to_string( *std::get(a->initializer) ) + ";\n", n.position() ); } // Handle object aliases: // - at function scope, it's const& // - at namespace scope, it's inline constexpr // - at type scope, it's also inline constexpr but see note (*) below else if (a->is_object_alias()) { auto type = std::string{"auto"}; if (a->type_id) { type = print_to_string(*a->type_id); } // (*) If this is at type scope, Cpp1 requires an out-of-line declaration dance // for some cases to work - see https://stackoverflow.com/questions/11928089/ if (n.parent_is_type()) { assert (n.parent_declaration->name()); if (printer.get_phase() == printer.phase1_type_defs_func_decls) { printer.print_cpp2( "static const " + type + " " + print_to_string(*n.identifier) + ";\n", n.position() ); } else if (printer.get_phase() == printer.phase2_func_defs) { // The following logic is not yet complete, so give a diagnostic for now if (n.parent_declaration->parent_is_type()) { errors.emplace_back( n.position(), "(temporary alpha limitation) an object alias cannot yet appear inside a nested type" ); return; } auto parent_template_params = std::string{}; auto parent_template_args = std::string{}; auto parent_qualifier = std::string{}; auto parent = n.parent_declaration; while (parent && parent->is_type()) { if (!parent_qualifier.empty()) { parent_qualifier.insert(0, "::"); } parent_qualifier.insert(0, parent->name()->to_string()); if (parent->template_parameters) { parent_template_params.insert(0, "template" + print_to_string(*parent->template_parameters)); for (auto const& param : parent->template_parameters->parameters) { assert(param->name()); if (parent_template_args.empty()) { parent_template_args = ""; } else { parent_template_args.insert(parent_template_args.size()-1, ","); } parent_template_args.insert(parent_template_args.size()-1, param->name()->as_string_view()); } } parent = parent->parent_declaration; } if (!parent_template_params.empty()) { parent_template_params += " "; } printer.print_cpp2( parent_template_params + "inline CPP2_CONSTEXPR " + type + parent_template_args + " " + parent_qualifier + parent_template_args + "::" + print_to_string(*n.identifier) + " = " + print_to_string( *std::get(a->initializer) ) + ";\n", n.position() ); } } // Otherwise, at function and namespace scope we can just declare else { auto intro = std::string{}; if (n.parent_is_function()) { intro = "const&"; } else if (n.parent_is_namespace()) { intro = "inline constexpr"; } printer.print_cpp2( type + " " + intro + " " + print_to_string(*n.identifier) + " = " + print_to_string( *std::get(a->initializer) ) + ";\n", n.position() ); } } else { assert(!"ICE: should be unreachable - invalid alias"); } return; } } // Handle other declarations auto need_to_generate_assignment = false; auto need_to_generate_move = false; if ( n.is_function() && n.has_name() ) { // reset the 'that' flags emitting_that_function = false; emitting_move_that_function = false; already_moved_that_members = {}; } auto is_main = !n.parent_declaration && n.has_name("main") ; auto is_in_type = n.parent_is_type(); if (!check_shadowing_of_type_scope_names(n)) { return; } current_declarations.push_back(&n); auto guard = finally([&]{ current_declarations.pop_back(); }); // If this is a function that has multiple return values, // first we need to emit the struct that contains the returns if ( printer.get_phase() == printer.phase1_type_defs_func_decls && n.is_function() ) { auto& func = std::get(n.type); assert(func); if (func->returns.index() == function_type_node::list) { auto& r = std::get(func->returns); assert(r); assert(std::ssize(r->parameters) > 0); printer.print_extra( "struct " ); printer.print_extra( *n.name() ); printer.print_extra( "_ret " ); emit(*r, true); printer.print_extra( "\n" ); } } // If this is a class definition that has data members before bases, // first we need to emit the aggregate that contains the members if ( n.is_type() && printer.get_phase() == printer.phase1_type_defs_func_decls ) { assert( n.initializer && n.initializer->is_compound() ); auto& compound_stmt = std::get(n.initializer->statement); assert(compound_stmt); auto found = false; for (auto& stmt : compound_stmt->statements) { if (!stmt->is_declaration()) { // We will already have emitted an error for this in sema.check return; } auto& decl = std::get(stmt->statement); assert(decl); assert(decl->name()); auto emit_as_base = decl->get_decl_if_type_scope_object_name_before_a_base_type(*decl->name()); if (emit_as_base) { printer.print_extra( "\nstruct " + print_to_string(*decl->parent_declaration->name()) + "_" + decl->name()->to_string() + "_as_base { " + print_to_string( *decl->get_object_type() ) + " " + decl->name()->to_string() + "; };" ); found = true; } } if (found) { printer.print_extra("\n"); } } // In class definitions, emit the explicit access specifier if there // is one, or default to private for data and public for functions if (printer.get_phase() == printer.phase1_type_defs_func_decls) { if (!n.is_default_access()) { assert (is_in_type); printer.print_cpp2(to_string(n.access) + ": ", n.position()); } else if (is_in_type) { if (n.is_object()) { printer.print_cpp2("private: ", n.position()); } else { printer.print_cpp2("public: ", n.position()); } } } // If this is a function definition and the function is inside // type(s) that have template parameters and/or requires clauses, // emit those outer template parameters and requires clauses too if ( printer.get_phase() == printer.phase2_func_defs && n.is_function() && n.initializer // only if the function has a definition (is not abstract) ) { auto parent_template_parameters = std::string{}; auto parent = n.parent_declaration; while ( parent && parent->is_type() ) { if (parent->requires_clause_expression) { parent_template_parameters = "requires( " + print_to_string(*parent->requires_clause_expression) + " )\n" + parent_template_parameters; } if (parent->template_parameters) { parent_template_parameters = "template " + print_to_string( *parent->template_parameters, false, true ) + " " + parent_template_parameters; } parent = parent->parent_declaration; } printer.print_cpp2(parent_template_parameters, n.position()); } // Now, emit our own template parameters if ( n.template_parameters && ( printer.get_phase() < printer.phase2_func_defs || n.is_object() || ( n.is_function() && n.has_name() // only if it is not unnamed function aka lambda && n.initializer // only if the function has a definition (is not abstract) && printer.get_phase() == printer.phase2_func_defs ) ) && ( !n.is_concept() || printer.get_phase() == printer.phase1_type_defs_func_decls ) ) { printer.print_cpp2("template", n.position()); emit(*n.template_parameters, false, true); printer.print_cpp2(" ", n.position()); } // User-defined type if (n.is_type()) { assert( n.initializer && n.initializer->is_compound() ); auto& compound_stmt = std::get(n.initializer->statement); if (printer.get_phase() != printer.phase2_func_defs) { if (n.requires_clause_expression) { printer.print_cpp2("requires( ", n.requires_pos); emit(*n.requires_clause_expression); printer.print_cpp2(" )\n", n.requires_pos); } printer.print_cpp2("class ", n.position()); emit(*n.identifier); // Type declaration if (printer.get_phase() == printer.phase0_type_decls) { printer.print_cpp2( ";\n", n.position() ); return; } } if ( n.is_type_final() && printer.get_phase() == printer.phase1_type_defs_func_decls ) { printer.print_cpp2( " final", n.position() ); } // Type definition auto separator = std::string{":"}; auto started_body = false; auto found_constructor = false; auto found_that_constructor = false; assert(compound_stmt); for (auto& stmt : compound_stmt->statements) { assert(stmt); if (!stmt->is_declaration()) { // We will already have emitted an error for this in sema.check return; } auto& decl = std::get(stmt->statement); assert(decl); if (decl->is_constructor()) { found_constructor = true; } if (decl->is_constructor_with_that()) { found_that_constructor = true; } // First we'll encounter the base types == subobjects named "this" // and any data members declared before them that we push into private bases assert(decl->name()); auto emit_as_base = decl->get_decl_if_type_scope_object_name_before_a_base_type(*decl->name()) || decl->has_name("this") ; if (emit_as_base) { // Do the sema check for these declarations here, because we're // handling them here instead of going through emit() for them if (!sema.check(*decl)) { return; } if (decl->has_name("this")) { if (printer.get_phase() == printer.phase1_type_defs_func_decls) { printer.print_cpp2( separator + " public " + print_to_string(*decl->get_object_type()), compound_stmt->position() ); separator = ","; } } else { if (printer.get_phase() == printer.phase1_type_defs_func_decls) { printer.print_cpp2( separator + " public " + print_to_string(*decl->parent_declaration->name()) + "_" + decl->name()->to_string() + "_as_base", compound_stmt->position() ); separator = ","; } } } // Then we'll switch to start the body == other members else { if (printer.get_phase() == printer.phase1_type_defs_func_decls) { if (!started_body) { printer.print_cpp2(" {", compound_stmt->position()); started_body = true; } } emit(*decl); } } // Ensure we emit the { even if there are only bases in the type if (printer.get_phase() == printer.phase1_type_defs_func_decls) { if (!started_body) { printer.print_cpp2(" {", compound_stmt->position()); } auto id = print_to_string(*n.identifier); auto indent = static_cast( std::clamp( compound_stmt->body_indent, n.position().colno, n.position().colno + 5 // sanity check ) ); auto prefix = "\n" + std::string( indent, ' ' ) + "public: "; if (n.member_function_generation) { // If no constructor was defined, there should only be // a default constructor, so generate that if (!found_constructor) { printer.print_extra( prefix + id + "() = default;" ); } // If no 'that' constructor was defined, disable copy/move // so that Cpp1 doesn't silently generate it anyway if (!found_that_constructor) { printer.print_extra( prefix + id + "(" + id + " const&) = delete; /* No 'that' constructor, suppress copy */" ); printer.print_extra( prefix + "auto operator=(" + id + " const&) -> void = delete;" ); } if (!found_constructor || !found_that_constructor) { printer.print_extra( "\n" ); } } printer.print_cpp2("};\n", compound_stmt->close_brace); } } // Namespace if (n.is_namespace()) { printer.print_cpp2("namespace ", n.position()); // "_" is the anonymous namespace, which is just whitespace in Cpp1 if (auto tok = n.identifier->get_token(); tok && *tok != "_" ) { emit(*n.identifier); } assert( n.initializer && n.initializer->is_compound() ); auto& compound_stmt = std::get(n.initializer->statement); printer.print_cpp2(" {", compound_stmt->position()); assert(compound_stmt); for (auto& stmt : compound_stmt->statements) { assert(stmt); if (!stmt->is_declaration()) { errors.emplace_back( stmt->position(), "a namespace scope must contain only declarations, not other code" ); return; } auto& decl = std::get(stmt->statement); assert(decl); emit(*decl); } printer.print_cpp2("}\n", compound_stmt->close_brace); } // Function else if ( n.is_function() && ( printer.get_phase() < printer.phase2_func_defs || n.initializer // only emit definition if the function has one (is not abstract) || n.is_defaultable_function() ) ) { auto is_streaming_operator = [](std::string_view sv) { return sv == "operator" ; }; auto is_binary_arithmetic_operator = [](std::string_view sv) { return sv == "operator+" || sv == "operator-" || sv == "operator*" || sv == "operator/" || sv == "operator%" ; }; auto emit_as_friend = n.name() && ( is_streaming_operator( n.name()->as_string_view() ) || (!n.is_function_with_this() && is_binary_arithmetic_operator( n.name()->as_string_view() )) ) ; // Start fresh (there may be one spurious leftover // requires-condition created during the declarations pass) function_requires_conditions = {}; auto& func = std::get(n.type); assert(func); current_functions.push( &n, n.find_parent_declared_value_set_functions() ); auto guard = finally([&]{ current_functions.pop(); }); // If this is at expression scope, we can't emit "[[nodiscard]] auto name" // so print the provided intro instead, which will be a Cpp1 lambda-introducer if (capture_intro != "") { assert (!n.identifier); printer.print_cpp2(capture_intro, n.position()); emit( *func, nullptr, is_main); } // Else start introducing a normal function else { assert (n.identifier); // Handle member functions std::string prefix = {}; std::string suffix1 = {}; std::string suffix2 = {}; if (n.is_constexpr) { prefix += "constexpr "; } if ( !n.has_initializer() && n.is_defaultable_function() ) { suffix2 += " = default"; } // If there's a 'this' parameter, handle it here (the parameter emission will skip it) // because Cpp1 syntax requires its information to be spread around the declaration syntax assert (func->parameters); if ( !func->parameters->parameters.empty() && func->parameters->parameters[0]->declaration->has_name("this") ) { assert (is_in_type); auto& this_ = func->parameters->parameters[0]; switch (this_->pass) { break;case passing_style::in: suffix1 += " const"; // Cpp1 ref-qualifiers don't belong on virtual functions if (!this_->is_polymorphic()) { suffix1 += "&"; } break;case passing_style::inout: // Cpp1 ref-qualifiers don't belong on virtual functions if (!this_->is_polymorphic()) { suffix1 += " &"; } break;case passing_style::out: ; // constructor is handled below break;case passing_style::move: suffix1 += " &&"; // We shouldn't be able to get into a state where these values // exist here, if we did it's our compiler bug break;case passing_style::copy: case passing_style::forward: default: errors.emplace_back( n.position(), "ICE: invalid parameter passing style, should have been rejected", true); } // Note: Include a phase check because Cpp1 does not allow // these on out-of-line definitions if (printer.get_phase() != printer.phase2_func_defs) { switch (this_->mod) { break;case parameter_declaration_node::modifier::implicit: ; break;case parameter_declaration_node::modifier::virtual_: prefix += "virtual "; if (!n.initializer) { suffix2 += " = 0"; } break;case parameter_declaration_node::modifier::override_: suffix2 += " override"; break;case parameter_declaration_node::modifier::final_: suffix2 += " final"; break;default: if ( func->is_constructor() && !func->is_constructor_with_that() && generating_assignment_from != &n ) { prefix += "explicit "; } } } } // Else if there isn't a 'this' parameter, but this function is in a type scope, // it's a Cpp1 non-member function so we need to say so (on the declaration only) else if ( is_in_type && printer.get_phase() != printer.phase2_func_defs ) { if (emit_as_friend) { prefix += "friend "; } else { prefix += "static "; } } // If there's a return type, it's [[nodiscard]] implicitly and all the time // -- for now there's no opt-out, wait and see whether we actually need one if ( func->has_non_void_return_type() && !func->is_assignment() && !func->is_compound_assignment() && ( printer.get_phase() == printer.phase1_type_defs_func_decls || n.has_initializer() // so we're printing it in phase 2 ) && ( !emit_as_friend // can't have an attribute on a friend declaration-not-definition || printer.get_phase() != printer.phase1_type_defs_func_decls ) && !( n.name() && is_streaming_operator(n.name()->as_string_view()) ) ) { printer.print_cpp2( "[[nodiscard]] ", n.position() ); } // Now we have all the pieces we need for the Cpp1 function declaration // For a special member function, we need to do more work to translate // in-body initialization statements to the Cpp1 mem-init-list syntax if ( n.is_constructor() || n.is_assignment() ) { assert( !is_main && suffix2.empty() && "ICE: an operator= shouldn't have been able to generate a suffix (or be main)" ); emit_special_member_function( n, prefix ); // If there's no inheritance and this operator= has two parameters, // it's setting from a single value -- either from the same type // (aka copy/move) or another type (a conversion) -- so recurse to // emit related functions if the user didn't write them by hand if ( !n.parent_is_polymorphic() && func->parameters->ssize() == 2 && generating_assignment_from != &n ) { assert(!current_functions.empty()); // A) Generate (A)ssignment from a constructor, // if the user didn't write the assignment function themselves if ( // A1) This is '(out this, that)' // and no '(inout this, that)' was written by the user ( &n == current_functions.back().declared_value_set_functions.out_this_in_that && !current_functions.back().declared_value_set_functions.inout_this_in_that ) || // A2) This is '(out this, move that)' // and no '(inout this, move that)' was written by the user // (*) and no '(inout this, that)' was written by the user (*) // // (*) This third test is to tie-break M2 and A2 in favor of M2. Both M2 and A2 // can generate a missing '(inout this, move that)', and if we have both // options then we should prefer to use M2 (generate move assignment from // copy assignment) rather than A2 (generate move assignment from move // construction) as M2 is a better fit (move assignment is more like copy // assignment than like move construction, because assignments are designed // structurally to set the value of an existing 'this' object) ( &n == current_functions.back().declared_value_set_functions.out_this_move_that && !current_functions.back().declared_value_set_functions.inout_this_move_that && !current_functions.back().declared_value_set_functions.inout_this_in_that ) || // A3) This is '(out this, something-other-than-that)' ( n.is_constructor() && !n.is_constructor_with_that() && !contains( current_functions.back().declared_value_set_functions.assignments_from, n.nth_parameter_type_name(2) ) ) ) { need_to_generate_assignment = true; } if (generating_move_from != &n) { // M) Generate (M)ove from copy, // if the user didn't write the move function themselves if ( // M1) This is '(out this, that)' // and no '(out this, move that)' was written by the user ( &n == current_functions.back().declared_value_set_functions.out_this_in_that && !current_functions.back().declared_value_set_functions.out_this_move_that ) || // M2) This is '(inout this, that)' // and no '(inout this, move that)' was written by the user ( &n == current_functions.back().declared_value_set_functions.inout_this_in_that && !current_functions.back().declared_value_set_functions.inout_this_move_that ) ) { need_to_generate_move = true; } } } } // For a destructor, we need to translate else if (n.is_destructor()) { assert( !is_main // prefix can be "virtual" // suffix1 will be " &&" though we'll ignore that // suffix2 can be "= 0" ); // Print the ~-prefixed type name instead of the operator= function name assert( n.parent_is_type() && n.parent_declaration->name() ); printer.print_cpp2( prefix + type_qualification_if_any_for(n) + "~" + print_to_string(*n.parent_declaration->name()), n.position() ); emit( *func, n.name(), false, true); printer.print_cpp2( suffix2, n.position() ); } // Ordinary functions are easier, do all their declarations except // don't emit abstract virtual functions in phase 2 else if ( n.initializer || printer.get_phase() < printer.phase2_func_defs ) { printer.print_cpp2( prefix, n.position() ); printer.print_cpp2( "auto ", n.position() ); if ( !emit_as_friend || printer.get_phase() != printer.phase2_func_defs ) { printer.print_cpp2( type_qualification_if_any_for(n), n.position() ); } emit( *n.name() ); emit( *func, n.name(), is_main, false, suffix1 ); printer.print_cpp2( suffix2, n.position() ); } } // If we're only emitting declarations, end the function declaration if ( printer.get_phase() == printer.phase1_type_defs_func_decls && !n.is_function_expression() ) { emit_requires_clause(); printer.print_cpp2( ";\n", n.position() ); // Note: Not just early "return;" here because we may need to // recurse to emit the generated operator= declarations too, // so all the definition work goes into a big 'else' branch } // Else emit the definition else if (n.initializer) { if (func->returns.index() == function_type_node::list) { auto& r = std::get(func->returns); function_returns.emplace_back(r.get()); } else if (func->returns.index() == function_type_node::id) { function_returns.emplace_back( &single_anon, // use special value as a note std::get(func->returns).pass, std::get(func->returns).type->is_wildcard() ); } else { function_returns.emplace_back(nullptr); // no return type at all } for (auto&& c : func->contracts) { auto print = std::string(); printer.emit_to_string(&print); emit(*c); printer.emit_to_string(); current_functions.back().prolog.statements.push_back(print); } if (func->returns.index() == function_type_node::list) { auto& r = std::get(func->returns); assert(r); for (auto& param : r->parameters) { assert(param && param->declaration); auto& decl = *param->declaration; assert(decl.is_object()); auto& id_expr = std::get(decl.type); assert(id_expr); auto loc = std::string{}; if (!decl.initializer) { loc += (" cpp2::deferred_init"); } loc += " "; loc += decl.name()->as_string_view(); if (decl.initializer) { std::string init; printer.emit_to_string(&init); printer.print_cpp2 ( " {", decl.initializer->position() ); if (!decl.initializer->is_expression()) { errors.emplace_back( decl.initializer->position(), "return value initializer must be an expression" ); return; } auto& expr = std::get(decl.initializer->statement); assert(expr); emit(*expr, false); printer.print_cpp2 ( "}", decl.initializer->position() ); printer.emit_to_string(); loc += init; } loc += ";"; current_functions.back().prolog.statements.push_back(loc); } } printer.preempt_position_push( n.equal_sign ); emit_requires_clause(); emit( *n.initializer, true, func->position(), func->returns.index() == function_type_node::empty, current_functions.back().prolog, current_functions.back().epilog ); printer.preempt_position_pop(); function_returns.pop_back(); } // Finally, do the potential recursions... // If this was a constructor and we want also want to emit // it as an assignment operator, do it via a recursive call if (need_to_generate_assignment) { // Reset the 'emitted' flags for (auto& statement : n.get_initializer_statements()) { statement->emitted = false; } // Then reposition and do the recursive call printer.reset_line_to(n.position().lineno); generating_assignment_from = &n; emit( n, capture_intro ); generating_assignment_from = {}; } // If this was a constructor and we want also want to emit // it as an assignment operator, do it via a recursive call if (need_to_generate_move) { // Reset the 'emitted' flags for (auto& statement : n.get_initializer_statements()) { statement->emitted = false; } // Then reposition and do the recursive call printer.reset_line_to(n.position().lineno); generating_move_from = &n; emit( n, capture_intro ); generating_move_from = {}; } } // Object with optional initializer else if ( n.is_object() && ( ( n.parent_is_namespace() && printer.get_phase() >= printer.phase1_type_defs_func_decls ) || ( n.parent_is_type() && printer.get_phase() == printer.phase1_type_defs_func_decls ) || ( n.parent_is_function() && printer.get_phase() == printer.phase2_func_defs ) ) ) { auto& type = std::get(n.type); if ( printer.get_phase() == printer.phase2_func_defs && type->is_concept() ) { return; } emit_requires_clause(); if ( printer.get_phase() != printer.phase2_func_defs && n.parent_is_namespace() && !type->is_concept() ) { printer.print_cpp2( "extern ", n.position() ); } // Emit "auto" for deduced types (of course) if (type->is_wildcard()) { assert(n.initializer); emit( *type, n.position() ); } // Otherwise, emit the type else { // If there isn't an initializer, use cpp2::deferred_init if (!n.initializer) { if (n.parent_is_function()) { printer.print_cpp2( "cpp2::deferred_init", n.position() ); } } printer.print_cpp2( " ", n.position()); assert(n.identifier); // If this is anonymous object (named "_"), generate a unique name if (n.has_name("_")) { if (n.has_wildcard_type()) { errors.emplace_back( n.identifier->position(), "an object can have an anonymous name or an anonymous type, but not both at the same type (rationale: if '_ := f();' were allowed to keep the returned object alive, that syntax would be dangerously close to '_ = f();' to discard the returned object, and such importantly opposite meanings deserve more than a one-character typo distance; and explicit discarding gets the nice syntax because it's likely more common)" ); return; } printer.print_cpp2( "auto_" + labelized_position(n.identifier->get_token()), n.identifier->position() ); } else { emit(*n.identifier); } if ( n.parent_is_namespace() && printer.get_phase() != printer.phase2_func_defs && !type->is_concept() ) { printer.print_cpp2( ";", n.position()); return; } // If there's an initializer, emit it if (n.initializer) { in_non_rvalue_context.push_back(true); printer.add_pad_in_this_line(-100); if (type->is_concept()) { printer.print_cpp2( " = ", n.position() ); } else { printer.print_cpp2( " {", n.position() ); } push_need_expression_list_parens(false); assert( n.initializer ); emit( *n.initializer, false ); pop_need_expression_list_parens(); if (!type->is_concept()) { printer.print_cpp2( "}", n.position() ); } in_non_rvalue_context.pop_back(); } printer.print_cpp2( "; ", n.position() ); } } //----------------------------------------------------------------------- // print_errors // auto print_errors() -> void { if (!errors.empty()) { // Delete the output file printer.abandon(); } error_entry const* prev = {}; bool print_fallback_errors = true; // true until we find a non-fallback message for (auto&& error : errors) { // Only print fallback error messages if we // haven't found a better (non-fallback) one yet if (!error.fallback) { print_fallback_errors = false; } if (error.fallback && !print_fallback_errors) { continue; } // Suppress adjacent duplicates (e.g., can arise when we // reenter operator= to emit it as an assignment operator) if ( !prev || error != *prev ) { error.print(std::cerr, strip_path(sourcefile)); } prev = &error; } if (violates_lifetime_safety) { std::cerr bool { return errors.empty(); } //----------------------------------------------------------------------- // debug_print // auto debug_print() -> void { // Only create debug output files if we managed to load the source file. // if (source_loaded) { auto out_source = std::ofstream{ sourcefile+"-source" }; source.debug_print( out_source ); auto out_tokens = std::ofstream{ sourcefile+"-tokens" }; tokens.debug_print( out_tokens ); auto out_parse = std::ofstream{ sourcefile+"-parse" }; parser.debug_print( out_parse ); auto out_symbols = std::ofstream{ sourcefile+"-symbols" }; sema.debug_print ( out_symbols ); } } //----------------------------------------------------------------------- // has_cpp1: pass through // auto has_cpp1() const -> bool { return source.has_cpp1(); } //----------------------------------------------------------------------- // has_cpp2: pass through // auto has_cpp2() const -> bool { return source.has_cpp2(); } }; } //=========================================================================== // main - driver //=========================================================================== using namespace std; using namespace cpp2; static auto enable_debug_output_files = false; static cmdline_processor::register_flag cmd_debug( 9, "debug", "Emit compiler debug output files", []{ enable_debug_output_files = true; } ); auto main( int argc, char* argv[] ) -> int { cmdline.set_args(argc, argv); cmdline.process_flags(); if (cmdline.help_was_requested()) { return EXIT_SUCCESS; } if (cmdline.arguments().empty()) { std::cerr