Avoid memset/memcpy null ub in block pass

The arena allocator has no problem with zero-size allocations (and
will just return the same pointer for each in this case), so just
do that to avoid null pointers.

diff --git a/ext/opcache/Optimizer/block_pass.c b/ext/opcache/Optimizer/block_pass.c
index e0d44dd5cc2a68ec2ff1792528489b741a8804e4..a635c55571c80367757d70b5b2a677d96bc29253 100644 (file)
--- a/ext/opcache/Optimizer/block_pass.c
+++ b/ext/opcache/Optimizer/block_pass.c
@@ -1912,17 +1912,11 @@ void zend_optimize_cfg(zend_op_array *op_array, zend_optimizer_ctx *ctx)
                zend_dump_op_array(op_array, ZEND_DUMP_CFG, "before block pass", &cfg);
        }
 
-       if (op_array->last_var || op_array->T) {
-               bitset_len = zend_bitset_len(op_array->last_var + op_array->T);
-               Tsource = zend_arena_calloc(&ctx->arena, op_array->last_var + op_array->T, sizeof(zend_op *));
-               same_t = zend_arena_alloc(&ctx->arena, op_array->last_var + op_array->T);
-               usage = zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
-       } else {
-               bitset_len = 0;
-               Tsource = NULL;
-               same_t = NULL;
-               usage = NULL;
-       }
+       bitset_len = zend_bitset_len(op_array->last_var + op_array->T);
+       Tsource = zend_arena_calloc(&ctx->arena, op_array->last_var + op_array->T, sizeof(zend_op *));
+       same_t = zend_arena_alloc(&ctx->arena, op_array->last_var + op_array->T);
+       usage = zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
+
        blocks = cfg.blocks;
        end = blocks + cfg.blocks_count;
        for (pass = 0; pass < PASSES; pass++) {