diff options
Diffstat (limited to 'builtin.c')
| -rw-r--r-- | builtin.c | 73 |
1 files changed, 72 insertions, 1 deletions
@@ -454,6 +454,77 @@ static struct symbol_op atomic_op = { }; +/// +// expand __builtin_object_size() +// +// :note: type 1 and type 3 are not supported because the +// needed information isn't available after evaluation. +static int expand_object_size(struct expression *expr, int cost) +{ + struct expression *arg = first_expression(expr->args); + int type = get_expression_value_silent(ptr_list_nth(expr->args, 1)); + unsigned long val = -1, off = 0; + + while (arg) { + switch (arg->type) { + case EXPR_IMPLIED_CAST: + case EXPR_CAST: + // ignore those + arg = arg->cast_expression; + continue; + case EXPR_BINOP: + // a constant add is (maybe) an offset + if (!arg->right || arg->op != '+' || arg->right->type != EXPR_VALUE) + break; + off += arg->right->value; + arg = arg->left; + continue; + case EXPR_PREOP: + // a deref is just intermediate variable + // and so the offset needs to be zeroed. + if (arg->op == '*') { + arg = arg->unop; + off = 0; + switch (arg->type) { + case EXPR_SYMBOL: + arg = arg->symbol->initializer; + continue; + default: + break; + } + } + break; + case EXPR_SYMBOL: + // the symbol we're looking after + val = bits_to_bytes(arg->symbol->bit_size); + break; + case EXPR_CALL: + // use alloc_size() attribute but only after linearization. + return UNSAFE; + default: + break; + } + break; + } + + if (val == -1) + val = (type & 2) ? 0 : val; + else if (type & 1) + return UNSAFE; + else + val -= off; + + expr->flags |= CEF_SET_ICE; + expr->type = EXPR_VALUE; + expr->value = val; + expr->taint = 0; + return 0; +} + +static struct symbol_op object_size_op = { + .expand = expand_object_size, +}; + /* * Builtin functions */ @@ -598,7 +669,7 @@ static const struct builtin_fn builtins_common[] = { { "__builtin_nan", &double_ctype, 0, { &const_string_ctype }}, { "__builtin_nanf", &float_ctype, 0, { &const_string_ctype }}, { "__builtin_nanl", &ldouble_ctype, 0, { &const_string_ctype }}, - { "__builtin_object_size", size_t_ctype, 0, { &const_ptr_ctype, &int_ctype }}, + { "__builtin_object_size", size_t_ctype, 0, { &const_ptr_ctype, &int_ctype }, .op = &object_size_op}, { "__builtin_parity", &int_ctype, 0, { &uint_ctype }, .op = &parity_op }, { "__builtin_parityl", &int_ctype, 0, { &ulong_ctype }, .op = &parity_op }, { "__builtin_parityll", &int_ctype, 0, { &ullong_ctype }, .op = &parity_op }, |