void scdf_mark_edge_feasible(scdf_ctx *scdf, int from, int to) {
uint32_t edge = scdf_edge(&scdf->ssa->cfg, from, to);
if (zend_bitset_in(scdf->feasible_edges, edge)) {
/* We already handled this edge */
return;
}
DEBUG_PRINT("Marking edge %d->%d feasible\n", from, to);
zend_bitset_incl(scdf->feasible_edges, edge);
if (!zend_bitset_in(scdf->executable_blocks, to)) {
if (!zend_bitset_in(scdf->block_worklist, to)) {
DEBUG_PRINT("Adding block %d to worklist\n", to);
}
zend_bitset_incl(scdf->block_worklist, to);
} else {
/* Block is already executable, only a new edge became feasible.
* Reevaluate phi nodes to account for changed source operands. */
zend_ssa_block *ssa_block = &scdf->ssa->blocks[to];
zend_ssa_phi *phi;
for (phi = ssa_block->phis; phi; phi = phi->next) {
zend_bitset_excl(scdf->phi_var_worklist, phi->ssa_var);
scdf->handlers.visit_phi(scdf, phi);
}
}
}
static zend_always_inline void add_to_worklists(context *ctx, int var_num, int check) {
zend_ssa_var *var = &ctx->ssa->vars[var_num];
if (var->definition >= 0) {
if (!check || zend_bitset_in(ctx->instr_dead, var->definition)) {
zend_bitset_incl(ctx->instr_worklist, var->definition);
}
} else if (var->definition_phi) {
if (!check || zend_bitset_in(ctx->phi_dead, var_num)) {
zend_bitset_incl(ctx->phi_worklist, var_num);
}
}
}
/* Removes unreachable blocks. This will remove both the instructions (and phis) in the
* blocks, as well as remove them from the successor / predecessor lists and mark them
* unreachable. Blocks already marked unreachable are not removed. */
int scdf_remove_unreachable_blocks(scdf_ctx *scdf) {
zend_ssa *ssa = scdf->ssa;
int i;
int removed_ops = 0;
for (i = 0; i < ssa->cfg.blocks_count; i++) {
if (!zend_bitset_in(scdf->executable_blocks, i)
&& (ssa->cfg.blocks[i].flags & ZEND_BB_REACHABLE)
&& !kept_alive_by_live_range(scdf, i)) {
removed_ops += ssa->cfg.blocks[i].len;
zend_ssa_remove_block(scdf->op_array, ssa, i);
}
}
return removed_ops;
}
/* If a live range starts in a reachable block and ends in an unreachable block, we should
* not eliminate the latter. While it cannot be reached, the FREE opcode of the loop var
* is necessary for the correctness of temporary compaction. */
static zend_bool kept_alive_by_live_range(scdf_ctx *scdf, uint32_t block) {
uint32_t i;
const zend_op_array *op_array = scdf->op_array;
const zend_cfg *cfg = &scdf->ssa->cfg;
for (i = 0; i < op_array->last_live_range; i++) {
zend_live_range *live_range = &op_array->live_range[i];
uint32_t start_block = cfg->map[live_range->start];
uint32_t end_block = cfg->map[live_range->end];
if (end_block == block && start_block != block
&& zend_bitset_in(scdf->executable_blocks, start_block)) {
return 1;
}
}
return 0;
}
/* If a live range starts in a reachable block and ends in an unreachable block, we should
* not eliminate the latter. While it cannot be reached, the FREE opcode of the loop var
* is necessary for the correctness of temporary compaction. */
static zend_bool kept_alive_by_loop_var_free(scdf_ctx *scdf, uint32_t block_idx) {
uint32_t i;
const zend_op_array *op_array = scdf->op_array;
const zend_cfg *cfg = &scdf->ssa->cfg;
const zend_basic_block *block = &cfg->blocks[block_idx];
for (i = block->start; i < block->start + block->len; i++) {
zend_op *opline = &op_array->opcodes[i];
if (opline->opcode == ZEND_FE_FREE ||
(opline->opcode == ZEND_FREE && opline->extended_value == ZEND_FREE_SWITCH)) {
int ssa_var = scdf->ssa->ops[i].op1_use;
if (ssa_var >= 0) {
int op_num = scdf->ssa->vars[ssa_var].definition;
uint32_t def_block;
ZEND_ASSERT(op_num >= 0);
def_block = cfg->map[op_num];
if (zend_bitset_in(scdf->executable_blocks, def_block)) {
return 1;
}
}
}
}
return 0;
}
int zend_build_ssa(zend_arena **arena, const zend_op_array *op_array, uint32_t build_flags, zend_ssa *ssa, uint32_t *func_flags) /* {{{ */
{
zend_basic_block *blocks = ssa->cfg.blocks;
zend_ssa_block *ssa_blocks;
int blocks_count = ssa->cfg.blocks_count;
uint32_t set_size;
zend_bitset tmp, gen, in;
int *var = NULL;
int i, j, k, changed;
zend_dfg dfg;
ALLOCA_FLAG(dfg_use_heap);
ALLOCA_FLAG(var_use_heap);
ssa->rt_constants = (build_flags & ZEND_RT_CONSTANTS);
ssa_blocks = zend_arena_calloc(arena, blocks_count, sizeof(zend_ssa_block));
if (!ssa_blocks) {
return FAILURE;
}
ssa->blocks = ssa_blocks;
/* Compute Variable Liveness */
dfg.vars = op_array->last_var + op_array->T;
dfg.size = set_size = zend_bitset_len(dfg.vars);
dfg.tmp = do_alloca((set_size * sizeof(zend_ulong)) * (blocks_count * 5 + 1), dfg_use_heap);
memset(dfg.tmp, 0, (set_size * sizeof(zend_ulong)) * (blocks_count * 5 + 1));
dfg.gen = dfg.tmp + set_size;
dfg.def = dfg.gen + set_size * blocks_count;
dfg.use = dfg.def + set_size * blocks_count;
dfg.in = dfg.use + set_size * blocks_count;
dfg.out = dfg.in + set_size * blocks_count;
if (zend_build_dfg(op_array, &ssa->cfg, &dfg, build_flags) != SUCCESS) {
free_alloca(dfg.tmp, dfg_use_heap);
return FAILURE;
}
if (build_flags & ZEND_SSA_DEBUG_LIVENESS) {
zend_dump_dfg(op_array, &ssa->cfg, &dfg);
}
tmp = dfg.tmp;
gen = dfg.gen;
in = dfg.in;
/* SSA construction, Step 1: Propagate "gen" sets in merge points */
do {
changed = 0;
for (j = 0; j < blocks_count; j++) {
if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
continue;
}
if (j >= 0 && (blocks[j].predecessors_count > 1 || j == 0)) {
zend_bitset_copy(tmp, gen + (j * set_size), set_size);
for (k = 0; k < blocks[j].predecessors_count; k++) {
i = ssa->cfg.predecessors[blocks[j].predecessor_offset + k];
while (i != -1 && i != blocks[j].idom) {
zend_bitset_union_with_intersection(tmp, tmp, gen + (i * set_size), in + (j * set_size), set_size);
i = blocks[i].idom;
}
}
if (!zend_bitset_equal(gen + (j * set_size), tmp, set_size)) {
zend_bitset_copy(gen + (j * set_size), tmp, set_size);
changed = 1;
}
}
}
} while (changed);
/* SSA construction, Step 2: Phi placement based on Dominance Frontiers */
var = do_alloca(sizeof(int) * (op_array->last_var + op_array->T), var_use_heap);
if (!var) {
free_alloca(dfg.tmp, dfg_use_heap);
return FAILURE;
}
zend_bitset_clear(tmp, set_size);
for (j = 0; j < blocks_count; j++) {
if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
continue;
}
if (blocks[j].predecessors_count > 1) {
zend_bitset_clear(tmp, set_size);
if (blocks[j].flags & ZEND_BB_IRREDUCIBLE_LOOP) {
/* Prevent any values from flowing into irreducible loops by
replacing all incoming values with explicit phis. The
register allocator depends on this property. */
zend_bitset_copy(tmp, in + (j * set_size), set_size);
} else {
for (k = 0; k < blocks[j].predecessors_count; k++) {
i = ssa->cfg.predecessors[blocks[j].predecessor_offset + k];
while (i != -1 && i != blocks[j].idom) {
zend_bitset_union_with_intersection(tmp, tmp, gen + (i * set_size), in + (j * set_size), set_size);
i = blocks[i].idom;
}
}
}
if (!zend_bitset_empty(tmp, set_size)) {
i = op_array->last_var + op_array->T;
while (i > 0) {
i--;
if (zend_bitset_in(tmp, i)) {
zend_ssa_phi *phi = zend_arena_calloc(arena, 1,
sizeof(zend_ssa_phi) +
sizeof(int) * blocks[j].predecessors_count +
sizeof(void*) * blocks[j].predecessors_count);
if (!phi) {
goto failure;
}
phi->sources = (int*)(((char*)phi) + sizeof(zend_ssa_phi));
memset(phi->sources, 0xff, sizeof(int) * blocks[j].predecessors_count);
phi->use_chains = (zend_ssa_phi**)(((char*)phi->sources) + sizeof(int) * ssa->cfg.blocks[j].predecessors_count);
phi->pi = -1;
phi->var = i;
phi->ssa_var = -1;
phi->next = ssa_blocks[j].phis;
ssa_blocks[j].phis = phi;
}
}
}
}
}
place_essa_pis(arena, op_array, build_flags, ssa, &dfg);
/* SSA construction, Step ?: Phi after Pi placement based on Dominance Frontiers */
for (j = 0; j < blocks_count; j++) {
if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
continue;
}
if (blocks[j].predecessors_count > 1) {
zend_bitset_clear(tmp, set_size);
if (blocks[j].flags & ZEND_BB_IRREDUCIBLE_LOOP) {
/* Prevent any values from flowing into irreducible loops by
replacing all incoming values with explicit phis. The
register allocator depends on this property. */
zend_bitset_copy(tmp, in + (j * set_size), set_size);
} else {
for (k = 0; k < blocks[j].predecessors_count; k++) {
i = ssa->cfg.predecessors[blocks[j].predecessor_offset + k];
while (i != -1 && i != blocks[j].idom) {
zend_ssa_phi *p = ssa_blocks[i].phis;
while (p) {
if (p) {
if (p->pi >= 0) {
if (zend_bitset_in(in + (j * set_size), p->var) &&
!zend_bitset_in(gen + (i * set_size), p->var)) {
zend_bitset_incl(tmp, p->var);
}
} else {
zend_bitset_excl(tmp, p->var);
}
}
p = p->next;
}
i = blocks[i].idom;
}
}
}
if (!zend_bitset_empty(tmp, set_size)) {
i = op_array->last_var + op_array->T;
while (i > 0) {
i--;
if (zend_bitset_in(tmp, i)) {
zend_ssa_phi **pp = &ssa_blocks[j].phis;
while (*pp) {
if ((*pp)->pi <= 0 && (*pp)->var == i) {
break;
}
pp = &(*pp)->next;
}
if (*pp == NULL) {
zend_ssa_phi *phi = zend_arena_calloc(arena, 1,
sizeof(zend_ssa_phi) +
sizeof(int) * blocks[j].predecessors_count +
sizeof(void*) * blocks[j].predecessors_count);
if (!phi) {
goto failure;
}
phi->sources = (int*)(((char*)phi) + sizeof(zend_ssa_phi));
memset(phi->sources, 0xff, sizeof(int) * blocks[j].predecessors_count);
phi->use_chains = (zend_ssa_phi**)(((char*)phi->sources) + sizeof(int) * ssa->cfg.blocks[j].predecessors_count);
phi->pi = -1;
phi->var = i;
phi->ssa_var = -1;
phi->next = NULL;
*pp = phi;
}
}
}
}
}
}
if (build_flags & ZEND_SSA_DEBUG_PHI_PLACEMENT) {
zend_dump_phi_placement(op_array, ssa);
}
/* SSA construction, Step 3: Renaming */
ssa->ops = zend_arena_calloc(arena, op_array->last, sizeof(zend_ssa_op));
memset(ssa->ops, 0xff, op_array->last * sizeof(zend_ssa_op));
memset(var, 0xff, (op_array->last_var + op_array->T) * sizeof(int));
/* Create uninitialized SSA variables for each CV */
for (j = 0; j < op_array->last_var; j++) {
var[j] = j;
}
ssa->vars_count = op_array->last_var;
if (zend_ssa_rename(op_array, build_flags, ssa, var, 0) != SUCCESS) {
failure:
free_alloca(var, var_use_heap);
free_alloca(dfg.tmp, dfg_use_heap);
return FAILURE;
}
free_alloca(var, var_use_heap);
free_alloca(dfg.tmp, dfg_use_heap);
return SUCCESS;
}
void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_ctx *ctx)
{
int T = op_array->T;
int offset = op_array->last_var;
uint32_t bitset_len;
zend_bitset taken_T; /* T index in use */
zend_op **start_of_T; /* opline where T is first used */
zend_bitset valid_T; /* Is the map_T valid */
int *map_T; /* Map's the T to its new index */
zend_op *opline, *end;
int currT;
int i;
int max = -1;
int var_to_free = -1;
void *checkpoint = zend_arena_checkpoint(ctx->arena);
bitset_len = zend_bitset_len(T);
taken_T = (zend_bitset) zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
start_of_T = (zend_op **) zend_arena_alloc(&ctx->arena, T * sizeof(zend_op *));
valid_T = (zend_bitset) zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
map_T = (int *) zend_arena_alloc(&ctx->arena, T * sizeof(int));
end = op_array->opcodes;
opline = &op_array->opcodes[op_array->last - 1];
/* Find T definition points */
while (opline >= end) {
if (ZEND_RESULT_TYPE(opline) & (IS_VAR | IS_TMP_VAR)) {
start_of_T[VAR_NUM(ZEND_RESULT(opline).var) - offset] = opline;
}
opline--;
}
zend_bitset_clear(valid_T, bitset_len);
zend_bitset_clear(taken_T, bitset_len);
end = op_array->opcodes;
opline = &op_array->opcodes[op_array->last - 1];
while (opline >= end) {
if ((ZEND_OP1_TYPE(opline) & (IS_VAR | IS_TMP_VAR))) {
currT = VAR_NUM(ZEND_OP1(opline).var) - offset;
if (opline->opcode == ZEND_ROPE_END) {
int num = (((opline->extended_value + 1) * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval);
int var;
var = max;
while (var >= 0 && !zend_bitset_in(taken_T, var)) {
var--;
}
max = MAX(max, var + num);
var = var + 1;
map_T[currT] = var;
zend_bitset_incl(valid_T, currT);
zend_bitset_incl(taken_T, var);
ZEND_OP1(opline).var = NUM_VAR(var + offset);
while (num > 1) {
num--;
zend_bitset_incl(taken_T, var + num);
}
} else {
if (!zend_bitset_in(valid_T, currT)) {
int use_new_var = 0;
/* Code in "finally" blocks may modify temorary variables.
* We allocate new temporaries for values that need to
* relive FAST_CALLs.
*/
if ((op_array->fn_flags & ZEND_ACC_HAS_FINALLY_BLOCK) &&
(opline->opcode == ZEND_RETURN ||
opline->opcode == ZEND_GENERATOR_RETURN ||
opline->opcode == ZEND_RETURN_BY_REF ||
opline->opcode == ZEND_FREE ||
opline->opcode == ZEND_FE_FREE)) {
zend_op *curr = opline;
while (--curr >= end) {
if (curr->opcode == ZEND_FAST_CALL) {
use_new_var = 1;
break;
} else if (curr->opcode != ZEND_FREE &&
curr->opcode != ZEND_FE_FREE &&
curr->opcode != ZEND_VERIFY_RETURN_TYPE &&
curr->opcode != ZEND_DISCARD_EXCEPTION) {
break;
}
}
}
if (use_new_var) {
i = ++max;
zend_bitset_incl(taken_T, i);
} else {
GET_AVAILABLE_T();
}
map_T[currT] = i;
zend_bitset_incl(valid_T, currT);
}
ZEND_OP1(opline).var = NUM_VAR(map_T[currT] + offset);
}
}
if ((ZEND_OP2_TYPE(opline) & (IS_VAR | IS_TMP_VAR))) {
currT = VAR_NUM(ZEND_OP2(opline).var) - offset;
if (!zend_bitset_in(valid_T, currT)) {
GET_AVAILABLE_T();
map_T[currT] = i;
zend_bitset_incl(valid_T, currT);
}
ZEND_OP2(opline).var = NUM_VAR(map_T[currT] + offset);
}
if (ZEND_RESULT_TYPE(opline) & (IS_VAR | IS_TMP_VAR)) {
currT = VAR_NUM(ZEND_RESULT(opline).var) - offset;
if (zend_bitset_in(valid_T, currT)) {
if (start_of_T[currT] == opline) {
/* ZEND_FAST_CALL can not share temporary var with others
* since the fast_var could also be set by ZEND_HANDLE_EXCEPTION
* which could be ahead of it */
if (opline->opcode != ZEND_FAST_CALL) {
zend_bitset_excl(taken_T, map_T[currT]);
}
}
ZEND_RESULT(opline).var = NUM_VAR(map_T[currT] + offset);
if (opline->opcode == ZEND_ROPE_INIT) {
if (start_of_T[currT] == opline) {
uint32_t num = ((opline->extended_value * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval);
while (num > 1) {
num--;
zend_bitset_excl(taken_T, map_T[currT]+num);
}
}
}
} else {
/* Code which gets here is using a wrongly built opcode such as RECV() */
GET_AVAILABLE_T();
map_T[currT] = i;
zend_bitset_incl(valid_T, currT);
ZEND_RESULT(opline).var = NUM_VAR(i + offset);
}
}
if (var_to_free >= 0) {
zend_bitset_excl(taken_T, var_to_free);
var_to_free = -1;
}
opline--;
}
if (op_array->live_range) {
for (i = 0; i < op_array->last_live_range; i++) {
op_array->live_range[i].var =
NUM_VAR(map_T[VAR_NUM(op_array->live_range[i].var & ~ZEND_LIVE_MASK) - offset] + offset) |
(op_array->live_range[i].var & ZEND_LIVE_MASK);
}
}
zend_arena_release(&ctx->arena, checkpoint);
op_array->T = max + 1;
}
/* This pass removes all CVs and temporaries that are completely unused. It does *not* merge any CVs or TMPs.
* This pass does not operate on SSA form anymore. */
void zend_optimizer_compact_vars(zend_op_array *op_array) {
int i;
ALLOCA_FLAG(use_heap1);
ALLOCA_FLAG(use_heap2);
uint32_t used_vars_len = zend_bitset_len(op_array->last_var + op_array->T);
zend_bitset used_vars = ZEND_BITSET_ALLOCA(used_vars_len, use_heap1);
uint32_t *vars_map = do_alloca((op_array->last_var + op_array->T) * sizeof(uint32_t), use_heap2);
uint32_t num_cvs, num_tmps;
/* Determine which CVs are used */
zend_bitset_clear(used_vars, used_vars_len);
for (i = 0; i < op_array->last; i++) {
zend_op *opline = &op_array->opcodes[i];
if (opline->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
zend_bitset_incl(used_vars, VAR_NUM(opline->op1.var));
}
if (opline->op2_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
zend_bitset_incl(used_vars, VAR_NUM(opline->op2.var));
}
if (opline->result_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
zend_bitset_incl(used_vars, VAR_NUM(opline->result.var));
if (opline->opcode == ZEND_ROPE_INIT) {
uint32_t num = ((opline->extended_value * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval);
while (num > 1) {
num--;
zend_bitset_incl(used_vars, VAR_NUM(opline->result.var) + num);
}
}
}
}
num_cvs = 0;
for (i = 0; i < op_array->last_var; i++) {
if (zend_bitset_in(used_vars, i)) {
vars_map[i] = num_cvs++;
} else {
vars_map[i] = (uint32_t) -1;
}
}
num_tmps = 0;
for (i = op_array->last_var; i < op_array->last_var + op_array->T; i++) {
if (zend_bitset_in(used_vars, i)) {
vars_map[i] = num_cvs + num_tmps++;
} else {
vars_map[i] = (uint32_t) -1;
}
}
free_alloca(used_vars, use_heap1);
if (num_cvs == op_array->last_var && num_tmps == op_array->T) {
free_alloca(vars_map, use_heap2);
return;
}
ZEND_ASSERT(num_cvs <= op_array->last_var);
ZEND_ASSERT(num_tmps <= op_array->T);
/* Update CV and TMP references in opcodes */
for (i = 0; i < op_array->last; i++) {
zend_op *opline = &op_array->opcodes[i];
if (opline->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
opline->op1.var = NUM_VAR(vars_map[VAR_NUM(opline->op1.var)]);
}
if (opline->op2_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
opline->op2.var = NUM_VAR(vars_map[VAR_NUM(opline->op2.var)]);
}
if (opline->result_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
opline->result.var = NUM_VAR(vars_map[VAR_NUM(opline->result.var)]);
}
}
/* Update TMP references in live ranges */
if (op_array->live_range) {
for (i = 0; i < op_array->last_live_range; i++) {
op_array->live_range[i].var =
(op_array->live_range[i].var & ZEND_LIVE_MASK) |
NUM_VAR(vars_map[VAR_NUM(op_array->live_range[i].var & ~ZEND_LIVE_MASK)]);
}
}
/* Update CV name table */
if (num_cvs != op_array->last_var) {
zend_string **names = safe_emalloc(sizeof(zend_string *), num_cvs, 0);
for (i = 0; i < op_array->last_var; i++) {
if (vars_map[i] != (uint32_t) -1) {
names[vars_map[i]] = op_array->vars[i];
} else {
zend_string_release(op_array->vars[i]);
}
}
efree(op_array->vars);
op_array->vars = names;
}
op_array->last_var = num_cvs;
op_array->T = num_tmps;
free_alloca(vars_map, use_heap2);
}
void scdf_solve(scdf_ctx *scdf, const char *name) {
zend_ssa *ssa = scdf->ssa;
DEBUG_PRINT("Start SCDF solve (%s)\n", name);
while (!zend_bitset_empty(scdf->instr_worklist, scdf->instr_worklist_len)
|| !zend_bitset_empty(scdf->phi_var_worklist, scdf->phi_var_worklist_len)
|| !zend_bitset_empty(scdf->block_worklist, scdf->block_worklist_len)
) {
int i;
while ((i = zend_bitset_pop_first(scdf->phi_var_worklist, scdf->phi_var_worklist_len)) >= 0) {
zend_ssa_phi *phi = ssa->vars[i].definition_phi;
ZEND_ASSERT(phi);
if (zend_bitset_in(scdf->executable_blocks, phi->block)) {
scdf->handlers.visit_phi(scdf, phi);
}
}
while ((i = zend_bitset_pop_first(scdf->instr_worklist, scdf->instr_worklist_len)) >= 0) {
int block_num = ssa->cfg.map[i];
if (zend_bitset_in(scdf->executable_blocks, block_num)) {
zend_basic_block *block = &ssa->cfg.blocks[block_num];
zend_op *opline = &scdf->op_array->opcodes[i];
zend_ssa_op *ssa_op = &ssa->ops[i];
if (opline->opcode == ZEND_OP_DATA) {
opline--;
ssa_op--;
}
scdf->handlers.visit_instr(scdf, opline, ssa_op);
if (i == block->start + block->len - 1) {
if (block->successors_count == 1) {
scdf_mark_edge_feasible(scdf, block_num, block->successors[0]);
} else if (block->successors_count > 1) {
scdf->handlers.mark_feasible_successors(scdf, block_num, block, opline, ssa_op);
}
}
}
}
while ((i = zend_bitset_pop_first(scdf->block_worklist, scdf->block_worklist_len)) >= 0) {
/* This block is now live. Interpret phis and instructions in it. */
zend_basic_block *block = &ssa->cfg.blocks[i];
zend_ssa_block *ssa_block = &ssa->blocks[i];
DEBUG_PRINT("Pop block %d from worklist\n", i);
zend_bitset_incl(scdf->executable_blocks, i);
{
zend_ssa_phi *phi;
for (phi = ssa_block->phis; phi; phi = phi->next) {
zend_bitset_excl(scdf->phi_var_worklist, phi->ssa_var);
scdf->handlers.visit_phi(scdf, phi);
}
}
if (block->len == 0) {
/* Zero length blocks don't have a last instruction that would normally do this */
scdf_mark_edge_feasible(scdf, i, block->successors[0]);
} else {
zend_op *opline;
int j, end = block->start + block->len;
for (j = block->start; j < end; j++) {
opline = &scdf->op_array->opcodes[j];
zend_bitset_excl(scdf->instr_worklist, j);
if (opline->opcode != ZEND_OP_DATA) {
scdf->handlers.visit_instr(scdf, opline, &ssa->ops[j]);
}
}
if (block->successors_count == 1) {
scdf_mark_edge_feasible(scdf, i, block->successors[0]);
} else if (block->successors_count > 1) {
if (opline->opcode == ZEND_OP_DATA) {
opline--;
j--;
}
scdf->handlers.mark_feasible_successors(scdf, i, block, opline, &ssa->ops[j-1]);
}
}
}
}
}
static inline void add_to_phi_worklist_no_val(context *ctx, int var_num) {
zend_ssa_var *var = &ctx->ssa->vars[var_num];
if (var->definition_phi && zend_bitset_in(ctx->phi_dead, var_num)) {
zend_bitset_incl(ctx->phi_worklist_no_val, var_num);
}
}
