diff options
| -rw-r--r-- | expand.c | 23 | ||||
| -rw-r--r-- | validation/constexpr-shift.c | 12 | ||||
| -rw-r--r-- | validation/expand/bad-shift.c | 64 |
3 files changed, 91 insertions, 8 deletions
@@ -158,19 +158,14 @@ Float: expr->type = EXPR_FVALUE; } -static void check_shift_count(struct expression *expr, struct expression *right) +static void warn_shift_count(struct expression *expr, struct symbol *ctype, long long count) { - struct symbol *ctype = expr->ctype; - long long count = get_longlong(right); - if (count < 0) { if (!Wshift_count_negative) return; warning(expr->pos, "shift count is negative (%lld)", count); return; } - if (count < ctype->bit_size) - return; if (ctype->type == SYM_NODE) ctype = ctype->ctype.base_type; @@ -179,6 +174,19 @@ static void check_shift_count(struct expression *expr, struct expression *right) warning(expr->pos, "shift too big (%llu) for type %s", count, show_typename(ctype)); } +/* Return true if constant shift size is valid */ +static bool check_shift_count(struct expression *expr, struct expression *right) +{ + struct symbol *ctype = expr->ctype; + long long count = get_longlong(right); + + if (count >= 0 && count < ctype->bit_size) + return true; + if (!conservative) + warn_shift_count(expr, ctype, count); + return false; +} + /* * CAREFUL! We need to get the size and sign of the * result right! @@ -197,9 +205,8 @@ static int simplify_int_binop(struct expression *expr, struct symbol *ctype) return 0; r = right->value; if (expr->op == SPECIAL_LEFTSHIFT || expr->op == SPECIAL_RIGHTSHIFT) { - if (conservative) + if (!check_shift_count(expr, right)) return 0; - check_shift_count(expr, right); } if (left->type != EXPR_VALUE) return 0; diff --git a/validation/constexpr-shift.c b/validation/constexpr-shift.c new file mode 100644 index 00000000..df01b74e --- /dev/null +++ b/validation/constexpr-shift.c @@ -0,0 +1,12 @@ +#define __is_constexpr(x) \ + (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) + +static void test(int x) { + static int b[] = { + [__builtin_choose_expr(__is_constexpr(1 << 1), 1, x)] = 0, + }; +} + +/* + * check-name: constexpr-shift + */ diff --git a/validation/expand/bad-shift.c b/validation/expand/bad-shift.c new file mode 100644 index 00000000..22c4341f --- /dev/null +++ b/validation/expand/bad-shift.c @@ -0,0 +1,64 @@ +#define MAX (sizeof(int) * __CHAR_BIT__) + +static int lmax(int a) +{ + return 1 << MAX; +} + +static int lneg(int a) +{ + return 1 << -1; +} + +static int rmax(int a) +{ + return 1 >> MAX; +} + +static int rneg(int a) +{ + return 1 >> -1; +} + +/* + * check-name: bad-shift + * check-command: test-linearize -Wno-decl $file + * + * check-output-start +lmax: +.L0: + <entry-point> + shl.32 %r1 <- $1, $32 + ret.32 %r1 + + +lneg: +.L2: + <entry-point> + shl.32 %r3 <- $1, $0xffffffff + ret.32 %r3 + + +rmax: +.L4: + <entry-point> + asr.32 %r5 <- $1, $32 + ret.32 %r5 + + +rneg: +.L6: + <entry-point> + asr.32 %r7 <- $1, $0xffffffff + ret.32 %r7 + + + * check-output-end + * + * check-error-start +expand/bad-shift.c:5:18: warning: shift too big (32) for type int +expand/bad-shift.c:10:18: warning: shift count is negative (-1) +expand/bad-shift.c:15:18: warning: shift too big (32) for type int +expand/bad-shift.c:20:18: warning: shift count is negative (-1) + * check-error-end + */ |