X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=parser.c;h=0c4fec0452b1633c4e10253115ee047fa85f8843;hb=5d50990437f0dfeccfd6fa44f74681ea94bbe4f2;hp=1fc7cea99a644887eac1a62e11337d95d82f50ae;hpb=5de5d366d9a1340a13aefd15533caaab1f45cb07;p=cparser diff --git a/parser.c b/parser.c index 1fc7cea..0c4fec0 100644 --- a/parser.c +++ b/parser.c @@ -39,17 +39,22 @@ struct declaration_specifiers_t { typedef declaration_t* (*parsed_declaration_func) (declaration_t *declaration); -static token_t token; -static token_t lookahead_buffer[MAX_LOOKAHEAD]; -static int lookahead_bufpos; -static stack_entry_t *environment_stack = NULL; -static stack_entry_t *label_stack = NULL; -static context_t *global_context = NULL; -static context_t *context = NULL; -static declaration_t *last_declaration = NULL; -static declaration_t *current_function = NULL; +static token_t token; +static token_t lookahead_buffer[MAX_LOOKAHEAD]; +static int lookahead_bufpos; +static stack_entry_t *environment_stack = NULL; +static stack_entry_t *label_stack = NULL; +static context_t *global_context = NULL; +static context_t *context = NULL; +static declaration_t *last_declaration = NULL; +static declaration_t *current_function = NULL; +static switch_statement_t *current_switch = NULL; +static statement_t *current_loop = NULL; +static goto_statement_t *goto_first = NULL; +static goto_statement_t *goto_last = NULL; static struct obstack temp_obst; +/** The current source position. */ #define HERE token.source_position static type_t *type_valist; @@ -131,6 +136,11 @@ static void *allocate_ast_zero(size_t size) return res; } +static declaration_t *allocate_declaration_zero(void) +{ + return allocate_ast_zero(sizeof(*allocate_declaration_zero())); +} + /** * Returns the size of a statement node. * @@ -627,7 +637,7 @@ static int get_rank(const type_t *type) assert(type->kind == TYPE_ATOMIC); const atomic_type_t *atomic_type = &type->atomic; - atomic_type_type_t atype = atomic_type->atype; + atomic_type_kind_t atype = atomic_type->akind; return atype; } @@ -817,8 +827,8 @@ static void semantic_assign(type_t *orig_type_left, expression_t **right, incompatible_assign_types: /* TODO: improve error message */ - errorf(HERE, "incompatible types in %s", context); - errorf(HERE, "'%T' <- '%T'", orig_type_left, orig_type_right); + errorf(HERE, "incompatible types in %s: '%T' <- '%T'", + context, orig_type_left, orig_type_right); } static expression_t *parse_constant_expression(void) @@ -843,7 +853,7 @@ static type_t *make_global_typedef(const char *name, type_t *type) { symbol_t *const symbol = symbol_table_insert(name); - declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0])); + declaration_t *const declaration = allocate_declaration_zero(); declaration->namespc = NAMESPACE_NORMAL; declaration->storage_class = STORAGE_CLASS_TYPEDEF; declaration->type = type; @@ -858,15 +868,15 @@ static type_t *make_global_typedef(const char *name, type_t *type) return typedef_type; } -static const char *parse_string_literals(void) +static string_t parse_string_literals(void) { assert(token.type == T_STRING_LITERAL); - const char *result = token.v.string; + string_t result = token.v.string; next_token(); - while(token.type == T_STRING_LITERAL) { - result = concat_strings(result, token.v.string); + while (token.type == T_STRING_LITERAL) { + result = concat_strings(&result, &token.v.string); next_token(); } @@ -969,13 +979,13 @@ static designator_t *parse_designation(void) #endif static initializer_t *initializer_from_string(array_type_t *type, - const char *string) + const string_t *const string) { /* TODO: check len vs. size of array type */ (void) type; initializer_t *initializer = allocate_initializer_zero(INITIALIZER_STRING); - initializer->string.string = string; + initializer->string.string = *string; return initializer; } @@ -1007,9 +1017,9 @@ static initializer_t *initializer_from_expression(type_t *type, if (element_type->kind == TYPE_ATOMIC) { switch (expression->kind) { case EXPR_STRING_LITERAL: - if (element_type->atomic.atype == ATOMIC_TYPE_CHAR) { + if (element_type->atomic.akind == ATOMIC_TYPE_CHAR) { return initializer_from_string(array_type, - expression->string.value); + &expression->string.value); } case EXPR_WIDE_STRING_LITERAL: { @@ -1246,17 +1256,23 @@ static initializer_t *parse_sub_initializer(type_t *type, return result; } -static initializer_t *parse_initializer(type_t *type) +static initializer_t *parse_initializer(type_t *const orig_type) { initializer_t *result; - type = skip_typeref(type); + type_t *const type = skip_typeref(orig_type); if(token.type != '{') { expression_t *expression = parse_assignment_expression(); + if (expression->base.datatype == NULL) { + /* something bad happens, don't produce further errors */ + return NULL; + } initializer_t *initializer = initializer_from_expression(type, expression); if(initializer == NULL) { - errorf(HERE, "initializer expression '%E', type '%T' is incompatible with type '%T'", expression, expression->base.datatype, type); + errorf(HERE, + "initializer expression '%E' of type '%T' is incompatible with type '%T'", + expression, expression->base.datatype, orig_type); } return initializer; } @@ -1280,7 +1296,7 @@ static initializer_t *parse_initializer(type_t *type) return result; } - +static declaration_t *append_declaration(declaration_t *declaration); static declaration_t *parse_compound_type_specifier(bool is_struct) { @@ -1320,16 +1336,16 @@ static declaration_t *parse_compound_type_specifier(bool is_struct) } if(declaration == NULL) { - declaration = allocate_ast_zero(sizeof(declaration[0])); - - if(is_struct) { - declaration->namespc = NAMESPACE_STRUCT; - } else { - declaration->namespc = NAMESPACE_UNION; - } + declaration = allocate_declaration_zero(); + declaration->namespc = + (is_struct ? NAMESPACE_STRUCT : NAMESPACE_UNION); declaration->source_position = token.source_position; declaration->symbol = symbol; - record_declaration(declaration); + declaration->parent_context = context; + if (symbol != NULL) { + environment_push(declaration); + } + append_declaration(declaration); } if(token.type == '{') { @@ -1356,7 +1372,7 @@ static declaration_t *parse_compound_type_specifier(bool is_struct) return declaration; } -static void parse_enum_entries(enum_type_t *const enum_type) +static void parse_enum_entries(type_t *const enum_type) { eat('{'); @@ -1367,15 +1383,15 @@ static void parse_enum_entries(enum_type_t *const enum_type) } do { - declaration_t *entry = allocate_ast_zero(sizeof(entry[0])); - if(token.type != T_IDENTIFIER) { parse_error_expected("while parsing enum entry", T_IDENTIFIER, 0); eat_block(); return; } + + declaration_t *const entry = allocate_declaration_zero(); entry->storage_class = STORAGE_CLASS_ENUM_ENTRY; - entry->type = (type_t*) enum_type; + entry->type = enum_type; entry->symbol = token.v.symbol; entry->source_position = token.source_position; next_token(); @@ -1419,11 +1435,11 @@ static type_t *parse_enum_specifier(void) } if(declaration == NULL) { - declaration = allocate_ast_zero(sizeof(declaration[0])); - - declaration->namespc = NAMESPACE_ENUM; + declaration = allocate_declaration_zero(); + declaration->namespc = NAMESPACE_ENUM; declaration->source_position = token.source_position; declaration->symbol = symbol; + declaration->parent_context = context; } type_t *const type = allocate_type_zero(TYPE_ENUM); @@ -1433,10 +1449,13 @@ static type_t *parse_enum_specifier(void) if(declaration->init.is_defined) { errorf(HERE, "multiple definitions of enum %Y", symbol); } - record_declaration(declaration); + if (symbol != NULL) { + environment_push(declaration); + } + append_declaration(declaration); declaration->init.is_defined = 1; - parse_enum_entries(&type->enumt); + parse_enum_entries(type); parse_attributes(); } @@ -1708,7 +1727,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers) finish_specifiers: if(type == NULL) { - atomic_type_type_t atomic_type; + atomic_type_kind_t atomic_type; /* match valid basic types */ switch(type_specifiers) { @@ -1819,7 +1838,7 @@ finish_specifiers: } type = allocate_type_zero(TYPE_ATOMIC); - type->atomic.atype = atomic_type; + type->atomic.akind = atomic_type; newtype = 1; } else { if(type_specifiers != 0) { @@ -1859,8 +1878,7 @@ static declaration_t *parse_identifier_list(void) declaration_t *declarations = NULL; declaration_t *last_declaration = NULL; do { - declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0])); - + declaration_t *const declaration = allocate_declaration_zero(); declaration->source_position = token.source_position; declaration->symbol = token.v.symbol; next_token(); @@ -2256,14 +2274,14 @@ static type_t *construct_declarator_type(construct_type_t *construct_list, static declaration_t *parse_declarator( const declaration_specifiers_t *specifiers, bool may_be_abstract) { - type_t *type = specifiers->type; - declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0])); + declaration_t *const declaration = allocate_declaration_zero(); declaration->storage_class = specifiers->storage_class; declaration->modifiers = specifiers->decl_modifiers; declaration->is_inline = specifiers->is_inline; construct_type_t *construct_type = parse_inner_declarator(declaration, may_be_abstract); + type_t *const type = specifiers->type; declaration->type = construct_declarator_type(construct_type, type); if(construct_type != NULL) { @@ -2314,6 +2332,11 @@ static declaration_t *internal_record_declaration( assert(declaration != previous_declaration); if (previous_declaration != NULL && previous_declaration->parent_context == context) { + /* can happen for K&R style declarations */ + if(previous_declaration->type == NULL) { + previous_declaration->type = declaration->type; + } + const type_t *const prev_type = skip_typeref(previous_declaration->type); if (!types_compatible(type, prev_type)) { errorf(declaration->source_position, @@ -2352,7 +2375,7 @@ warn_redundant_declaration: errorf(declaration->source_position, "static declaration of '%Y' follows non-static declaration", symbol); errorf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol); } else { - if (old_storage_class != STORAGE_CLASS_EXTERN) { + if (old_storage_class != STORAGE_CLASS_EXTERN && !is_function_definition) { goto warn_redundant_declaration; } if (new_storage_class == STORAGE_CLASS_NONE) { @@ -2453,7 +2476,7 @@ static void parse_init_declarator_rest(declaration_t *declaration) case INITIALIZER_STRING: { initializer_string_t *const string = &initializer->string; - cnst->conste.v.int_value = strlen(string->string) + 1; + cnst->conste.v.int_value = string->string.size; break; } @@ -2487,8 +2510,7 @@ static void parse_anonymous_declaration_rest( { eat(';'); - declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0])); - + declaration_t *const declaration = allocate_declaration_zero(); declaration->type = specifiers->type; declaration->storage_class = specifiers->storage_class; declaration->source_position = specifiers->source_position; @@ -2549,11 +2571,32 @@ static void parse_declaration_rest(declaration_t *ndeclaration, static declaration_t *finished_kr_declaration(declaration_t *declaration) { - /* TODO: check that it was actually a parameter that gets a type */ + symbol_t *symbol = declaration->symbol; + if(symbol == NULL) { + errorf(HERE, "anonymous declaration not valid as function parameter"); + return declaration; + } + namespace_t namespc = (namespace_t) declaration->namespc; + if(namespc != NAMESPACE_NORMAL) { + return record_declaration(declaration); + } + + declaration_t *previous_declaration = get_declaration(symbol, namespc); + if(previous_declaration == NULL || + previous_declaration->parent_context != context) { + errorf(HERE, "expected declaration of a function parameter, found '%Y'", + symbol); + return declaration; + } - /* we should have a declaration for the parameter in the current - * scope */ - return record_declaration(declaration); + if(previous_declaration->type == NULL) { + previous_declaration->type = declaration->type; + previous_declaration->storage_class = declaration->storage_class; + previous_declaration->parent_context = context; + return previous_declaration; + } else { + return record_declaration(declaration); + } } static void parse_declaration(parsed_declaration_func finished_declaration) @@ -2649,6 +2692,31 @@ static void parse_kr_declaration_list(declaration_t *declaration) declaration->type = type; } +/** + * Check if all labels are defined in the current function. + */ +static void check_for_missing_labels(void) +{ + bool first_err = true; + for (const goto_statement_t *goto_statement = goto_first; + goto_statement != NULL; + goto_statement = goto_statement->next) { + const declaration_t *label = goto_statement->label; + + if (label->source_position.input_name == NULL) { + if (first_err) { + first_err = false; + diagnosticf("%s: In function '%Y':\n", + current_function->source_position.input_name, + current_function->symbol); + } + errorf(goto_statement->statement.source_position, + "label '%Y' used but not defined", label->symbol); + } + } + goto_first = goto_last = NULL; +} + static void parse_external_declaration(void) { /* function-definitions and declarations both start with declaration @@ -2690,7 +2758,8 @@ static void parse_external_declaration(void) /* note that we don't skip typerefs: the standard doesn't allow them here * (so we can't use is_type_function here) */ if(type->kind != TYPE_FUNCTION) { - errorf(HERE, "declarator '%#T' has a body but is not a function type", type, ndeclaration->symbol); + errorf(HERE, "declarator '%#T' has a body but is not a function type", + type, ndeclaration->symbol); eat_block(); return; } @@ -2721,7 +2790,11 @@ static void parse_external_declaration(void) declaration_t *parameter = declaration->context.declarations; for( ; parameter != NULL; parameter = parameter->next) { - assert(parameter->parent_context == NULL || parameter->parent_context == context); + if(parameter->parent_context == &ndeclaration->context) { + parameter->parent_context = context; + } + assert(parameter->parent_context == NULL + || parameter->parent_context == context); parameter->parent_context = context; environment_push(parameter); } @@ -2737,6 +2810,7 @@ static void parse_external_declaration(void) current_function = declaration; declaration->init.statement = parse_compound_statement(); + check_for_missing_labels(); assert(current_function == declaration); current_function = old_current_function; @@ -2772,15 +2846,12 @@ static void parse_struct_declarators(const declaration_specifiers_t *specifiers) type_t *type = make_bitfield_type(base_type, size); - declaration = allocate_ast_zero(sizeof(declaration[0])); - + declaration = allocate_declaration_zero(); declaration->namespc = NAMESPACE_NORMAL; declaration->storage_class = STORAGE_CLASS_NONE; declaration->source_position = token.source_position; declaration->modifiers = specifiers->decl_modifiers; declaration->type = type; - - record_declaration(declaration); } else { declaration = parse_declarator(specifiers,/*may_be_abstract=*/true); @@ -2862,10 +2933,15 @@ static expression_t *create_invalid_expression(void) return expression; } +/** + * Prints an error message if an expression was expected but not read + */ static expression_t *expected_expression_error(void) { - errorf(HERE, "expected expression, got token '%K'", &token); - + /* skip the error message if the error token was read */ + if (token.type != T_ERROR) { + errorf(HERE, "expected expression, got token '%K'", &token); + } next_token(); return create_invalid_expression(); @@ -2935,18 +3011,24 @@ static declaration_t *create_implicit_function(symbol_t *symbol, free_type(ntype); } - declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0])); - + declaration_t *const declaration = allocate_declaration_zero(); declaration->storage_class = STORAGE_CLASS_EXTERN; declaration->type = type; declaration->symbol = symbol; declaration->source_position = source_position; declaration->parent_context = global_context; + context_t *old_context = context; + set_context(global_context); + environment_push(declaration); + /* prepend the declaration to the global declarations list */ declaration->next = context->declarations; context->declarations = declaration; + assert(context == global_context); + set_context(old_context); + return declaration; } @@ -3209,7 +3291,6 @@ static expression_t *parse_function_keyword(void) expression->expression.kind = EXPR_FUNCTION; expression->expression.datatype = type_string; - expression->value = current_function->symbol->string; return (expression_t*) expression; } @@ -3228,7 +3309,6 @@ static expression_t *parse_pretty_function_keyword(void) expression->expression.kind = EXPR_PRETTY_FUNCTION; expression->expression.datatype = type_string; - expression->value = current_function->symbol->string; return (expression_t*) expression; } @@ -3545,6 +3625,21 @@ static expression_t *parse_primary_expression(void) return create_invalid_expression(); } +/** + * Check if the expression has the character type and issue a warning then. + */ +static void check_for_char_index_type(const expression_t *expression) { + type_t *type = expression->base.datatype; + type_t *base_type = skip_typeref(type); + + if (base_type->base.kind == TYPE_ATOMIC) { + if (base_type->atomic.akind == ATOMIC_TYPE_CHAR) { + warningf(expression->base.source_position, + "array subscript has type '%T'", type); + } + } +} + static expression_t *parse_array_expression(unsigned precedence, expression_t *left) { @@ -3572,12 +3667,14 @@ static expression_t *parse_array_expression(unsigned precedence, return_type = pointer->points_to; array_access->array_ref = left; array_access->index = inside; + check_for_char_index_type(inside); } else if(is_type_pointer(type_inside)) { pointer_type_t *pointer = &type_inside->pointer; return_type = pointer->points_to; array_access->array_ref = inside; array_access->index = left; array_access->flipped = true; + check_for_char_index_type(left); } else { errorf(HERE, "array access on object with non-pointer types '%T', '%T'", type_left, type_inside); } @@ -4008,6 +4105,9 @@ static void semantic_dereference(unary_expression_t *expression) expression->expression.datatype = result_type; } +/** + * Check the semantic of the address taken expression. + */ static void semantic_take_addr(unary_expression_t *expression) { expression_t *value = expression->value; @@ -4021,6 +4121,11 @@ static void semantic_take_addr(unary_expression_t *expression) reference_expression_t *reference = (reference_expression_t*) value; declaration_t *declaration = reference->declaration; if(declaration != NULL) { + if (declaration->storage_class == STORAGE_CLASS_REGISTER) { + errorf(expression->expression.source_position, + "address of register variable '%Y' requested", + declaration->symbol); + } declaration->address_taken = 1; } } @@ -4032,13 +4137,14 @@ static void semantic_take_addr(unary_expression_t *expression) static expression_t *parse_##unexpression_type(unsigned precedence) \ { \ eat(token_type); \ - \ + \ expression_t *unary_expression \ = allocate_expression_zero(unexpression_type); \ + unary_expression->base.source_position = HERE; \ unary_expression->unary.value = parse_sub_expression(precedence); \ \ sfunc(&unary_expression->unary); \ - \ + \ return unary_expression; \ } @@ -4774,11 +4880,45 @@ static statement_t *parse_case_statement(void) statement->case_label.expression = parse_expression(); expect(':'); + + if (! is_constant_expression(statement->case_label.expression)) { + errorf(statement->base.source_position, + "case label does not reduce to an integer constant"); + } else { + /* TODO: check if the case label is already known */ + if (current_switch != NULL) { + /* link all cases into the switch statement */ + if (current_switch->last_case == NULL) { + current_switch->first_case = + current_switch->last_case = &statement->case_label; + } else { + current_switch->last_case->next = &statement->case_label; + } + } else { + errorf(statement->base.source_position, + "case label not within a switch statement"); + } + } statement->case_label.label_statement = parse_statement(); return statement; } +/** + * Finds an existing default label of a switch statement. + */ +static case_label_statement_t * +find_default_label(const switch_statement_t *statement) +{ + for (case_label_statement_t *label = statement->first_case; + label != NULL; + label = label->next) { + if (label->expression == NULL) + return label; + } + return NULL; +} + /** * Parse a default statement. */ @@ -4791,6 +4931,25 @@ static statement_t *parse_default_statement(void) statement->base.source_position = token.source_position; expect(':'); + if (current_switch != NULL) { + const case_label_statement_t *def_label = find_default_label(current_switch); + if (def_label != NULL) { + errorf(HERE, "multiple default labels in one switch"); + errorf(def_label->statement.source_position, + "this is the first default label"); + } else { + /* link all cases into the switch statement */ + if (current_switch->last_case == NULL) { + current_switch->first_case = + current_switch->last_case = &statement->case_label; + } else { + current_switch->last_case->next = &statement->case_label; + } + } + } else { + errorf(statement->base.source_position, + "'default' label not within a switch statement"); + } statement->label.label_statement = parse_statement(); return statement; @@ -4811,7 +4970,7 @@ static declaration_t *get_label(symbol_t *symbol) } /* otherwise we need to create a new one */ - declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0])); + declaration_t *const declaration = allocate_declaration_zero(); declaration->namespc = NAMESPACE_LABEL; declaration->symbol = symbol; @@ -4847,7 +5006,7 @@ static statement_t *parse_label_statement(void) label_statement->statement.source_position = token.source_position; label_statement->label = label; - expect(':'); + eat(':'); if(token.type == '}') { /* TODO only warn? */ @@ -4896,13 +5055,28 @@ static statement_t *parse_switch(void) statement->statement.source_position = token.source_position; expect('('); - statement->expression = parse_expression(); + expression_t *const expr = parse_expression(); + type_t *const type = promote_integer(skip_typeref(expr->base.datatype)); + statement->expression = create_implicit_cast(expr, type); expect(')'); + + switch_statement_t *rem = current_switch; + current_switch = statement; statement->body = parse_statement(); + current_switch = rem; return (statement_t*) statement; } +static statement_t *parse_loop_body(statement_t *const loop) +{ + statement_t *const rem = current_loop; + current_loop = loop; + statement_t *const body = parse_statement(); + current_loop = rem; + return body; +} + /** * Parse a while statement. */ @@ -4917,7 +5091,8 @@ static statement_t *parse_while(void) expect('('); statement->condition = parse_expression(); expect(')'); - statement->body = parse_statement(); + + statement->body = parse_loop_body((statement_t*)statement); return (statement_t*) statement; } @@ -4933,7 +5108,7 @@ static statement_t *parse_do(void) statement->statement.kind = STATEMENT_DO_WHILE; statement->statement.source_position = token.source_position; - statement->body = parse_statement(); + statement->body = parse_loop_body((statement_t*)statement); expect(T_while); expect('('); statement->condition = parse_expression(); @@ -4979,7 +5154,7 @@ static statement_t *parse_for(void) statement->step = parse_expression(); } expect(')'); - statement->body = parse_statement(); + statement->body = parse_loop_body((statement_t*)statement); assert(context == &statement->context); set_context(last_context); @@ -5012,6 +5187,13 @@ static statement_t *parse_goto(void) statement->label = label; + /* remember the goto's in a list for later checking */ + if (goto_last == NULL) { + goto_first = goto_last = statement; + } else { + goto_last->next = statement; + } + expect(';'); return (statement_t*) statement; @@ -5022,13 +5204,19 @@ static statement_t *parse_goto(void) */ static statement_t *parse_continue(void) { + statement_t *statement; + if (current_loop == NULL) { + errorf(HERE, "continue statement not within loop"); + statement = NULL; + } else { + statement = allocate_statement_zero(STATEMENT_CONTINUE); + + statement->base.source_position = token.source_position; + } + eat(T_continue); expect(';'); - statement_t *statement = allocate_ast_zero(sizeof(statement[0])); - statement->kind = STATEMENT_CONTINUE; - statement->base.source_position = token.source_position; - return statement; } @@ -5037,16 +5225,54 @@ static statement_t *parse_continue(void) */ static statement_t *parse_break(void) { + statement_t *statement; + if (current_switch == NULL && current_loop == NULL) { + errorf(HERE, "break statement not within loop or switch"); + statement = NULL; + } else { + statement = allocate_statement_zero(STATEMENT_BREAK); + + statement->base.source_position = token.source_position; + } + eat(T_break); expect(';'); - statement_t *statement = allocate_ast_zero(sizeof(statement[0])); - statement->kind = STATEMENT_BREAK; - statement->base.source_position = token.source_position; - return statement; } +/** + * Check if a given declaration represents a local variable. + */ +static bool is_local_var_declaration(const declaration_t *declaration) { + switch ((storage_class_tag_t) declaration->storage_class) { + case STORAGE_CLASS_NONE: + case STORAGE_CLASS_AUTO: + case STORAGE_CLASS_REGISTER: { + const type_t *type = skip_typeref(declaration->type); + if(is_type_function(type)) { + return false; + } else { + return true; + } + } + default: + return false; + } +} + +/** + * Check if a given expression represents a local variable. + */ +static bool is_local_variable(const expression_t *expression) +{ + if (expression->base.kind != EXPR_REFERENCE) { + return false; + } + const declaration_t *declaration = expression->reference.declaration; + return is_local_var_declaration(declaration); +} + /** * Parse a return statement. */ @@ -5081,16 +5307,26 @@ static statement_t *parse_return(void) if(is_type_atomic(return_type, ATOMIC_TYPE_VOID) && !is_type_atomic(return_value_type, ATOMIC_TYPE_VOID)) { - warningf(HERE, "'return' with a value, in function returning void"); + warningf(statement->statement.source_position, + "'return' with a value, in function returning void"); return_value = NULL; } else { if(return_type != NULL) { semantic_assign(return_type, &return_value, "'return'"); } } + /* check for returning address of a local var */ + if (return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) { + const expression_t *expression = return_value->unary.value; + if (is_local_variable(expression)) { + warningf(statement->statement.source_position, + "function returns address of local variable"); + } + } } else { if(!is_type_atomic(return_type, ATOMIC_TYPE_VOID)) { - warningf(HERE, "'return' without value, in function returning non-void"); + warningf(statement->statement.source_position, + "'return' without value, in function returning non-void"); } } statement->return_value = return_value;