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More accurate symbolic constraints oferflow/unserflow handling (better fix for bug #76074).

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This commit is contained in:
Dmitry Stogov
2018-03-13 10:44:53 +03:00
parent 998a2ddc37
commit 44ba557de5
1 changed files with 19 additions and 12 deletions
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31
ext/opcache/Optimizer/zend_inference.c
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@@ -158,15 +158,12 @@
} while (0)
static inline zend_bool add_will_overflow(zend_long a, zend_long b) {
return (b > 0 && a > ZEND_LONG_MAX - b)
|| (b < 0 && a < ZEND_LONG_MIN - b);
return (b > 0 && a > ZEND_LONG_MAX - b);
}
#if 0
static inline zend_bool sub_will_overflow(zend_long a, zend_long b) {
return (b > 0 && a < ZEND_LONG_MIN + b)
|| (b < 0 && a > ZEND_LONG_MAX + b);
static inline zend_bool add_will_underflow(zend_long a, zend_long b) {
return (b < 0 && a < ZEND_LONG_MIN - b);
}
#endif
static void zend_ssa_check_scc_var(const zend_op_array *op_array, zend_ssa *ssa, int var, int *index, int *dfs, int *root, zend_worklist_stack *stack) /* {{{ */
{
@@ -836,8 +833,13 @@ int zend_inference_calc_range(const zend_op_array *op_array, zend_ssa *ssa, int
tmp->min = MAX(constraint->range.min, tmp->min);
#ifdef SYM_RANGE
} else if (narrowing && ssa->var_info[constraint->min_ssa_var].has_range) {
tmp->underflow = ssa->var_info[constraint->min_ssa_var].range.underflow && tmp->underflow;
if (!add_will_overflow(ssa->var_info[constraint->min_ssa_var].range.min, constraint->range.min)) {
if ((ssa->var_info[constraint->min_ssa_var].range.underflow
|| add_will_underflow(ssa->var_info[constraint->min_ssa_var].range.min, constraint->range.min))
&& tmp->underflow) {
tmp->underflow = 1;
tmp->min = ZEND_LONG_MIN;
} else {
tmp->underflow = 0;
tmp->min = MAX(ssa->var_info[constraint->min_ssa_var].range.min + constraint->range.min, tmp->min);
}
#endif
@@ -847,10 +849,15 @@ int zend_inference_calc_range(const zend_op_array *op_array, zend_ssa *ssa, int
tmp->overflow = constraint->range.overflow && tmp->overflow;
#ifdef SYM_RANGE
} else if (narrowing && ssa->var_info[constraint->max_ssa_var].has_range) {
if (!add_will_overflow(ssa->var_info[constraint->max_ssa_var].range.max, constraint->range.max)) {
if ((ssa->var_info[constraint->min_ssa_var].range.overflow
|| add_will_overflow(ssa->var_info[constraint->min_ssa_var].range.max, constraint->range.max))
&& tmp->overflow) {
tmp->overflow = 1;
tmp->max = ZEND_LONG_MAX;
} else {
tmp->overflow = 0;
tmp->max = MIN(ssa->var_info[constraint->max_ssa_var].range.max + constraint->range.max, tmp->max);
}
tmp->overflow = ssa->var_info[constraint->max_ssa_var].range.overflow && tmp->overflow;
#endif
}
} else if (narrowing) {
@@ -859,7 +866,7 @@ int zend_inference_calc_range(const zend_op_array *op_array, zend_ssa *ssa, int
tmp->min = constraint->range.min;
#ifdef SYM_RANGE
} else if (narrowing && ssa->var_info[constraint->min_ssa_var].has_range) {
if (add_will_overflow(ssa->var_info[constraint->min_ssa_var].range.min, constraint->range.min)) {
if (add_will_underflow(ssa->var_info[constraint->min_ssa_var].range.min, constraint->range.min)) {
tmp->underflow = 1;
tmp->min = ZEND_LONG_MIN;
} else {