Fix phpGH-17577: JIT packed type guard crash

When a guard check is created for a variable to check if it's a packed array,
it is possible that there was no prior type check for that variable.
This happens in the global scope for example when the variable aliases.
In the test, this causes a dereference of address 8 because the integer
element in `$a` is interpreted as an array address.

This patch adds a check to see if the guard is handled.
If we were not able to determine or guard the type then we also cannot know the array is packed.

Closes phpGH-17584.

Author: ndossche

NEWS

@@ -14,6 +14,7 @@ PHP                                                                        NEWS
 - Opcache:
   . Fixed bug GH-17654 (Multiple classes using same trait causes function
     JIT crash). (nielsdos)
+  . Fixed bug GH-17577 (JIT packed type guard crash). (nielsdos, Dmitry)
 
 - PHPDBG:
   . Partially fixed bug GH-17387 (Trivial crash in phpdbg lexer). (nielsdos)

ext/opcache/jit/zend_jit_trace.c

@@ -1745,7 +1745,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin
 						if (!(orig_op1_type & IS_TRACE_PACKED)) {
 							zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];
 
-							if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
+							if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
+							 && (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
 								info->type |= MAY_BE_PACKED_GUARD;
 								info->type &= ~MAY_BE_ARRAY_PACKED;
 							}
@@ -1754,7 +1755,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin
 								&& val_type != IS_UNDEF) {
 							zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];
 
-							if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
+							if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
+							 && (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
 								info->type |= MAY_BE_PACKED_GUARD;
 								info->type &= ~(MAY_BE_ARRAY_NUMERIC_HASH|MAY_BE_ARRAY_STRING_HASH);
 							}
@@ -1833,7 +1835,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin
 
 						zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];
 
-						if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
+						if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
+						 && (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
 							info->type |= MAY_BE_PACKED_GUARD;
 							if (orig_op1_type & IS_TRACE_PACKED) {
 								info->type &= ~(MAY_BE_ARRAY_NUMERIC_HASH|MAY_BE_ARRAY_STRING_HASH);
@@ -1935,7 +1938,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin
 
 						zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];
 
-						if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
+						if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
+						 && (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
 							info->type |= MAY_BE_PACKED_GUARD;
 							if (orig_op1_type & IS_TRACE_PACKED) {
 								info->type &= ~(MAY_BE_ARRAY_NUMERIC_HASH|MAY_BE_ARRAY_STRING_HASH);
@@ -1965,7 +1969,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin
 
 						zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];
 
-						if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
+						if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
+						 && (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
 							info->type |= MAY_BE_PACKED_GUARD;
 							info->type &= ~MAY_BE_ARRAY_PACKED;
 						}
@@ -4164,10 +4169,14 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 			if ((info & MAY_BE_PACKED_GUARD) != 0
 			 && (trace_buffer->stop == ZEND_JIT_TRACE_STOP_LOOP
 			  || trace_buffer->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_CALL
-			  || trace_buffer->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_RET)
+			  || (trace_buffer->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_RET
+			   && (opline-1)->result_type == IS_VAR
+			   && EX_VAR_TO_NUM((opline-1)->result.var) == i))
 			 && (ssa->vars[i].use_chain != -1
 			  || (ssa->vars[i].phi_use_chain
 			   && !(ssa->var_info[ssa->vars[i].phi_use_chain->ssa_var].type & MAY_BE_PACKED_GUARD)))) {
+				ZEND_ASSERT(STACK_TYPE(stack, i) == IS_ARRAY);
+
 				if (!zend_jit_packed_guard(&dasm_state, opline, EX_NUM_TO_VAR(i), info)) {
 					goto jit_failure;
 				}

ext/opcache/tests/jit/gh17577.phpt

@@ -0,0 +1,27 @@
+--TEST--
+GH-17577 (JIT packed type guard crash)
+--EXTENSIONS--
+opcache
+--INI--
+opcache.jit_buffer_size=16M
+opcache.jit_hot_func=1
+--FILE--
+<?php
+$a = array(
+    array(1,2,3),
+    0,
+);
+function my_dump($var) {
+}
+foreach($a as $b) {
+    for ($i = 0; $i < 3; $i++) {
+        my_dump($b[$i]);
+    }
+}
+?>
+--EXPECTF--
+Warning: Trying to access array offset on int in %s on line %d
+
+Warning: Trying to access array offset on int in %s on line %d
+
+Warning: Trying to access array offset on int in %s on line %d