}
}
+static void mark_decls_read(expression_t *expr, declaration_t *lhs_decl);
+
+static declaration_t *determine_lhs_decl(expression_t *const expr, declaration_t *lhs_decl)
+{
+ switch (expr->kind) {
+ case EXPR_REFERENCE: {
+ declaration_t *const decl = expr->reference.declaration;
+ return decl;
+ }
+
+ case EXPR_ARRAY_ACCESS: {
+ expression_t *const ref = expr->array_access.array_ref;
+ declaration_t * decl = NULL;
+ if (is_type_array(skip_typeref(ref->base.type))) {
+ decl = determine_lhs_decl(ref, lhs_decl);
+ lhs_decl = decl;
+ }
+ mark_decls_read(expr->array_access.index, lhs_decl);
+ return decl;
+ }
+
+ case EXPR_SELECT: {
+ if (is_type_compound(skip_typeref(expr->base.type))) {
+ return determine_lhs_decl(expr->select.compound, lhs_decl);
+ } else {
+ mark_decls_read(expr->select.compound, lhs_decl);
+ return NULL;
+ }
+ }
+
+ case EXPR_UNARY_DEREFERENCE: {
+ expression_t *const val = expr->unary.value;
+ if (val->kind == EXPR_UNARY_TAKE_ADDRESS) {
+ /* *&x is a NOP */
+ return determine_lhs_decl(val->unary.value, lhs_decl);
+ } else {
+ mark_decls_read(val, NULL);
+ return NULL;
+ }
+ }
+
+ default:
+ mark_decls_read(expr, NULL);
+ return NULL;
+ }
+}
+
+#define DECL_ANY ((declaration_t*)-1)
+
+/**
+ * Mark declarations, which are read. This is used to deted variables, which
+ * are never read.
+ * Example:
+ * x = x + 1;
+ * x is not marked as "read", because it is only read to calculate its own new
+ * value.
+ *
+ * x += y; y += x;
+ * x and y are not detected as "not read", because multiple variables are
+ * involved.
+ */
+static void mark_decls_read(expression_t *const expr, declaration_t *lhs_decl)
+{
+ switch (expr->kind) {
+ case EXPR_REFERENCE: {
+ declaration_t *const decl = expr->reference.declaration;
+ if (lhs_decl != decl && lhs_decl != DECL_ANY)
+ decl->read = true;
+ return;
+ }
+
+ case EXPR_CALL:
+ // TODO respect pure/const
+ mark_decls_read(expr->call.function, NULL);
+ for (call_argument_t *arg = expr->call.arguments; arg != NULL; arg = arg->next) {
+ mark_decls_read(arg->expression, NULL);
+ }
+ return;
+
+ case EXPR_CONDITIONAL:
+ // TODO lhs_decl should depend on whether true/false have an effect
+ mark_decls_read(expr->conditional.condition, NULL);
+ if (expr->conditional.true_expression != NULL)
+ mark_decls_read(expr->conditional.true_expression, lhs_decl);
+ mark_decls_read(expr->conditional.false_expression, lhs_decl);
+ return;
+
+ case EXPR_SELECT:
+ mark_decls_read(expr->select.compound, lhs_decl);
+ return;
+
+ case EXPR_ARRAY_ACCESS: {
+ expression_t *const ref = expr->array_access.array_ref;
+ mark_decls_read(ref, lhs_decl);
+ lhs_decl = determine_lhs_decl(ref, lhs_decl);
+ mark_decls_read(expr->array_access.index, lhs_decl);
+ return;
+ }
+
+ case EXPR_VA_ARG:
+ mark_decls_read(expr->va_arge.ap, lhs_decl);
+ return;
+
+ case EXPR_UNARY_CAST:
+ /* Special case: Use void cast to mark a variable as "read" */
+ if (is_type_atomic(skip_typeref(expr->base.type), ATOMIC_TYPE_VOID))
+ lhs_decl = NULL;
+ /* FALLTHROUGH */
+
+ case EXPR_UNARY_NEGATE:
+ case EXPR_UNARY_PLUS:
+ case EXPR_UNARY_BITWISE_NEGATE:
+ case EXPR_UNARY_NOT:
+ case EXPR_UNARY_DEREFERENCE:
+ case EXPR_UNARY_TAKE_ADDRESS:
+ case EXPR_UNARY_POSTFIX_INCREMENT:
+ case EXPR_UNARY_POSTFIX_DECREMENT:
+ case EXPR_UNARY_PREFIX_INCREMENT:
+ case EXPR_UNARY_PREFIX_DECREMENT:
+ case EXPR_UNARY_CAST_IMPLICIT:
+ case EXPR_UNARY_ASSUME:
+ mark_decls_read(expr->unary.value, lhs_decl);
+ return;
+
+ case EXPR_BINARY_ADD:
+ case EXPR_BINARY_SUB:
+ case EXPR_BINARY_MUL:
+ case EXPR_BINARY_DIV:
+ case EXPR_BINARY_MOD:
+ case EXPR_BINARY_EQUAL:
+ case EXPR_BINARY_NOTEQUAL:
+ case EXPR_BINARY_LESS:
+ case EXPR_BINARY_LESSEQUAL:
+ case EXPR_BINARY_GREATER:
+ case EXPR_BINARY_GREATEREQUAL:
+ case EXPR_BINARY_BITWISE_AND:
+ case EXPR_BINARY_BITWISE_OR:
+ case EXPR_BINARY_BITWISE_XOR:
+ case EXPR_BINARY_LOGICAL_AND:
+ case EXPR_BINARY_LOGICAL_OR:
+ case EXPR_BINARY_SHIFTLEFT:
+ case EXPR_BINARY_SHIFTRIGHT:
+ case EXPR_BINARY_COMMA:
+ case EXPR_BINARY_ISGREATER:
+ case EXPR_BINARY_ISGREATEREQUAL:
+ case EXPR_BINARY_ISLESS:
+ case EXPR_BINARY_ISLESSEQUAL:
+ case EXPR_BINARY_ISLESSGREATER:
+ case EXPR_BINARY_ISUNORDERED:
+ mark_decls_read(expr->binary.left, lhs_decl);
+ mark_decls_read(expr->binary.right, lhs_decl);
+ return;
+
+ case EXPR_BINARY_ASSIGN:
+ case EXPR_BINARY_MUL_ASSIGN:
+ case EXPR_BINARY_DIV_ASSIGN:
+ case EXPR_BINARY_MOD_ASSIGN:
+ case EXPR_BINARY_ADD_ASSIGN:
+ case EXPR_BINARY_SUB_ASSIGN:
+ case EXPR_BINARY_SHIFTLEFT_ASSIGN:
+ case EXPR_BINARY_SHIFTRIGHT_ASSIGN:
+ case EXPR_BINARY_BITWISE_AND_ASSIGN:
+ case EXPR_BINARY_BITWISE_XOR_ASSIGN:
+ case EXPR_BINARY_BITWISE_OR_ASSIGN: {
+ if (lhs_decl == DECL_ANY)
+ lhs_decl = NULL;
+ lhs_decl = determine_lhs_decl(expr->binary.left, lhs_decl);
+ mark_decls_read(expr->binary.right, lhs_decl);
+ return;
+ }
+
+ case EXPR_VA_START:
+ determine_lhs_decl(expr->va_starte.ap, lhs_decl);
+ return;
+
+ case EXPR_UNKNOWN:
+ case EXPR_INVALID:
+ case EXPR_CONST:
+ case EXPR_CHARACTER_CONSTANT:
+ case EXPR_WIDE_CHARACTER_CONSTANT:
+ case EXPR_STRING_LITERAL:
+ case EXPR_WIDE_STRING_LITERAL:
+ case EXPR_COMPOUND_LITERAL: // TODO init?
+ case EXPR_SIZEOF:
+ case EXPR_CLASSIFY_TYPE:
+ case EXPR_ALIGNOF:
+ case EXPR_FUNCNAME:
+ case EXPR_BUILTIN_SYMBOL:
+ case EXPR_BUILTIN_CONSTANT_P:
+ case EXPR_BUILTIN_PREFETCH:
+ case EXPR_OFFSETOF:
+ case EXPR_STATEMENT: // TODO
+ case EXPR_LABEL_ADDRESS:
+ case EXPR_BINARY_BUILTIN_EXPECT:
+ return;
+ }
+
+ panic("unhandled expression");
+}
+
static designator_t *parse_designation(void)
{
designator_t *result = NULL;
}
expression_t *expression = parse_assignment_expression();
+ mark_decls_read(expression, NULL);
if (must_be_constant && !is_initializer_constant(expression)) {
errorf(&expression->base.source_position,
"Initialisation expression '%E' is not constant\n",
label_first = label_last = NULL;
}
+static void warn_unused_decl(declaration_t *decl, declaration_t *end, char const *const what)
+{
+ for (; decl != NULL; decl = decl->next) {
+ if (decl->implicit)
+ continue;
+
+ if (!decl->used) {
+ print_in_function();
+ warningf(&decl->source_position, "%s '%Y' is unused", what, decl->symbol);
+ } else if (!decl->read) {
+ print_in_function();
+ warningf(&decl->source_position, "%s '%Y' is never read", what, decl->symbol);
+ }
+
+ if (decl == end)
+ break;
+ }
+}
+
+static void check_unused_variables(statement_t const *const stmt)
+{
+ // TODO statement expressions
+ switch (stmt->kind) {
+ case STATEMENT_COMPOUND:
+ for (statement_t const *s = stmt->compound.statements; s != NULL; s = s->base.next) {
+ check_unused_variables(s);
+ }
+ return;
+
+ case STATEMENT_FOR: {
+ warn_unused_decl(stmt->fors.scope.declarations, NULL, "variable");
+ check_unused_variables(stmt->fors.body);
+ return;
+ }
+
+ case STATEMENT_IF:
+ check_unused_variables(stmt->ifs.true_statement);
+ if (stmt->ifs.false_statement != NULL)
+ check_unused_variables(stmt->ifs.false_statement);
+ return;
+
+ case STATEMENT_SWITCH:
+ check_unused_variables(stmt->switchs.body);
+ return;
+
+ case STATEMENT_LABEL:
+ check_unused_variables(stmt->label.statement);
+ return;
+
+ case STATEMENT_CASE_LABEL:
+ check_unused_variables(stmt->case_label.statement);
+ return;
+
+ case STATEMENT_WHILE:
+ check_unused_variables(stmt->whiles.body);
+ return;
+
+ case STATEMENT_DO_WHILE:
+ check_unused_variables(stmt->do_while.body);
+ return;
+
+ case STATEMENT_DECLARATION: {
+ declaration_statement_t const *const decls = &stmt->declaration;
+ warn_unused_decl(decls->declarations_begin, decls->declarations_end, "variable");
+ return;
+ }
+
+ case STATEMENT_EXPRESSION:
+ // TODO statement expressions
+ return;
+
+ case STATEMENT_INVALID:
+ case STATEMENT_EMPTY:
+ case STATEMENT_RETURN:
+ case STATEMENT_CONTINUE:
+ case STATEMENT_BREAK:
+ case STATEMENT_GOTO:
+ case STATEMENT_ASM:
+ case STATEMENT_LEAVE:
+ return;
+
+ case STATEMENT_MS_TRY: {
+ ms_try_statement_t const *const ms_try = &stmt->ms_try;
+ check_unused_variables(ms_try->try_statement);
+ check_unused_variables(ms_try->final_statement);
+ return;
+ }
+ }
+
+ panic("unhandled statement");
+}
+
/**
* Check declarations of current_function for unused entities.
*/
if (warning.unused_parameter) {
const scope_t *scope = ¤t_function->scope;
- if (is_sym_main(current_function->symbol)) {
- /* do not issue unused warnings for main */
- return;
- }
- const declaration_t *parameter = scope->declarations;
- for (; parameter != NULL; parameter = parameter->next) {
- if (! parameter->used) {
- print_in_function();
- warningf(¶meter->source_position,
- "unused parameter '%Y'", parameter->symbol);
- }
+ /* do not issue unused warnings for main */
+ if (!is_sym_main(current_function->symbol)) {
+ warn_unused_decl(scope->declarations, NULL, "parameter");
}
}
if (warning.unused_variable) {
+ check_unused_variables(current_function->init.statement);
}
}
errorf(&expression->base.source_position,
"asm output argument is not an lvalue");
}
+
+ if (argument->constraints.begin[0] == '+')
+ mark_decls_read(expression, NULL);
+ } else {
+ mark_decls_read(expression, NULL);
}
argument->expression = expression;
expect(')');
expect('(');
add_anchor_token(')');
- statement->ifs.condition = parse_expression();
+ expression_t *const expr = parse_expression();
+ statement->ifs.condition = expr;
+ mark_decls_read(expr, NULL);
rem_anchor_token(')');
expect(')');
expect('(');
add_anchor_token(')');
expression_t *const expr = parse_expression();
+ mark_decls_read(expr, NULL);
type_t * type = skip_typeref(expr->base.type);
if (is_type_integer(type)) {
type = promote_integer(type);
expect('(');
add_anchor_token(')');
- statement->whiles.condition = parse_expression();
+ expression_t *const cond = parse_expression();
+ statement->whiles.condition = cond;
+ mark_decls_read(cond, NULL);
rem_anchor_token(')');
expect(')');
expect(T_while);
expect('(');
add_anchor_token(')');
- statement->do_while.condition = parse_expression();
+ expression_t *const cond = parse_expression();
+ statement->do_while.condition = cond;
+ mark_decls_read(cond, NULL);
rem_anchor_token(')');
expect(')');
expect(';');
add_anchor_token(';');
expression_t *const init = parse_expression();
statement->fors.initialisation = init;
+ mark_decls_read(init, DECL_ANY);
if (warning.unused_value && !expression_has_effect(init)) {
warningf(&init->base.source_position,
"initialisation of 'for'-statement has no effect");
if (token.type != ';') {
add_anchor_token(';');
- statement->fors.condition = parse_expression();
+ expression_t *const cond = parse_expression();
+ statement->fors.condition = cond;
+ mark_decls_read(cond, NULL);
rem_anchor_token(';');
}
expect(';');
if (token.type != ')') {
expression_t *const step = parse_expression();
statement->fors.step = step;
+ mark_decls_read(step, DECL_ANY);
if (warning.unused_value && !expression_has_effect(step)) {
warningf(&step->base.source_position,
"step of 'for'-statement has no effect");
if (GNU_MODE && token.type == '*') {
next_token();
expression_t *expression = parse_expression();
+ mark_decls_read(expression, NULL);
/* Argh: although documentation say the expression must be of type void *,
* gcc excepts anything that can be casted into void * without error */
expression_t *return_value = NULL;
if (token.type != ';') {
return_value = parse_expression();
+ mark_decls_read(return_value, NULL);
}
const type_t *const func_type = current_function->type;
expression_t *const expr = parse_expression();
statement->expression.expression = expr;
+ mark_decls_read(expr, DECL_ANY);
expect(';');
expect('(');
add_anchor_token(')');
expression_t *const expr = parse_expression();
+ mark_decls_read(expr, NULL);
type_t * type = skip_typeref(expr->base.type);
if (is_type_integer(type)) {
type = promote_integer(type);
projects / cparser / commitdiff