Keep information about SSA variables, that may be modified indirectly.

Author: dstogov

ext/opcache/Optimizer/zend_cfg.c

@@ -598,6 +598,8 @@ int zend_build_cfg(zend_arena **arena, const zend_op_array *op_array, uint32_t b
 	/* Build CFG, Step 4, Mark Reachable Basic Blocks */
 	zend_mark_reachable_blocks(op_array, cfg, 0);
 
+	cfg->dynamic = (flags & ZEND_FUNC_INDIRECT_VAR_ACCESS);
+
 	if (func_flags) {
 		*func_flags |= flags;
 	}

ext/opcache/Optimizer/zend_cfg.h

@@ -92,6 +92,7 @@ typedef struct _zend_cfg {
 	unsigned int      split_at_live_ranges : 1;
 	unsigned int      split_at_calls : 1;
 	unsigned int      split_at_recv : 1;
+	unsigned int      dynamic : 1;        /* accesses varables by name   */
 } zend_cfg;
 
 /* Build Flags */

ext/opcache/Optimizer/zend_inference.c

@@ -3835,21 +3835,14 @@ static int zend_infer_types(const zend_op_array *op_array, const zend_script *sc
 	/* Narrowing integer initialization to doubles */
 	zend_type_narrowing(op_array, script, ssa);
 
-	for (j = 0; j < op_array->last_var; j++) {
-		/* $php_errormsg and $http_response_header may be updated indirectly */
-		if (zend_string_equals_literal(op_array->vars[j], "php_errormsg")) {
-			int i;
-			for (i = 0; i < ssa_vars_count; i++) {
-				if (ssa->vars[i].var == j) {
-					ssa_var_info[i].type |= MAY_BE_STRING | MAY_BE_RC1 | MAY_BE_RCN;
-				}
-			}
-		} else if (zend_string_equals_literal(op_array->vars[j], "http_response_header")) {
-			int i;
-			for (i = 0; i < ssa_vars_count; i++) {
-				if (ssa->vars[i].var == j) {
-					ssa_var_info[i].type |= MAY_BE_ARRAY | MAY_BE_ARRAY_KEY_LONG | MAY_BE_ARRAY_OF_STRING | MAY_BE_RC1 | MAY_BE_RCN;
-				}
+	for (j = 0; j < ssa_vars_count; j++) {
+		if (ssa->vars[j].alias) {
+			if (ssa->vars[j].alias == PHP_ERRORMSG_ALIAS) {
+				ssa_var_info[j].type |= MAY_BE_STRING | MAY_BE_RC1 | MAY_BE_RCN;
+			} else if (ssa->vars[j].alias == PHP_ERRORMSG_ALIAS) {
+				ssa_var_info[j].type |= MAY_BE_ARRAY | MAY_BE_ARRAY_KEY_LONG | MAY_BE_ARRAY_OF_STRING | MAY_BE_RC1 | MAY_BE_RCN;
+			} else {
+				ssa_var_info[j].type = MAY_BE_UNDEF | MAY_BE_RC1 | MAY_BE_RCN | MAY_BE_REF | MAY_BE_ANY | MAY_BE_ARRAY_KEY_ANY | MAY_BE_ARRAY_OF_ANY | MAY_BE_ARRAY_OF_REF;
 			}
 		}
 	}

ext/opcache/Optimizer/zend_ssa.c

@@ -1100,6 +1100,22 @@ int zend_ssa_compute_use_def_chains(zend_arena **arena, const zend_op_array *op_
 		}
 	}
 
+	/* Mark indirectly accessed variables */
+	for (i = 0; i < op_array->last_var; i++) {
+		if (ssa->cfg.dynamic) {
+			ssa_vars[i].alias = SYMTABLE_ALIAS;
+		} else if (zend_string_equals_literal(op_array->vars[i], "php_errormsg")) {
+			ssa_vars[i].alias = PHP_ERRORMSG_ALIAS;
+		} else if (zend_string_equals_literal(op_array->vars[i], "http_response_header")) {
+			ssa_vars[i].alias = HTTP_RESPONSE_HEADER_ALIAS;
+		}
+	}
+	for (i = op_array->last_var; i < ssa->vars_count; i++) {
+		if (ssa_vars[i].var < op_array->last_var) {
+			ssa_vars[i].alias = ssa_vars[ssa_vars[i].var].alias;
+		}
+	}
+
 	return SUCCESS;
 }
 /* }}} */

ext/opcache/Optimizer/zend_ssa.h

@@ -92,6 +92,13 @@ typedef struct _zend_ssa_op {
 	int                    res_use_chain;
 } zend_ssa_op;
 
+typedef enum _zend_ssa_alias_kind {
+	NO_ALIAS,
+	SYMTABLE_ALIAS,
+	PHP_ERRORMSG_ALIAS,
+	HTTP_RESPONSE_HEADER_ALIAS
+} zend_ssa_alias_kind;
+
 typedef struct _zend_ssa_var {
 	int                    var;            /* original var number; op.var for CVs and following numbers for VARs and TMP_VARs */
 	int                    scc;            /* strongly connected component */
@@ -102,6 +109,7 @@ typedef struct _zend_ssa_var {
 	zend_ssa_phi          *sym_use_chain;  /* uses of this value in Pi constaints */
 	unsigned int           no_val : 1;     /* value doesn't mater (used as op1 in ZEND_ASSIGN) */
 	unsigned int           scc_entry : 1;
+	zend_ssa_alias_kind    alias : 2;  /* value may be changed indirectly */
 } zend_ssa_var;
 
 typedef struct _zend_ssa_var_info {