Keep CPU regesters used by deoptimizer

Author: dstogov

ext/opcache/jit/zend_jit_trace.c

@@ -2752,7 +2752,8 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 	if (!parent_trace) {
 		zend_jit_prologue(&dasm_state);
 	}
-	zend_jit_trace_begin(&dasm_state, ZEND_JIT_TRACE_NUM);
+	zend_jit_trace_begin(&dasm_state, ZEND_JIT_TRACE_NUM,
+		parent_trace ? &zend_jit_traces[parent_trace] : NULL, exit_num);
 
 	if (!parent_trace) {
 		zend_jit_set_opline(&dasm_state, opline);

ext/opcache/jit/zend_jit_x86.dasc

@@ -2867,12 +2867,47 @@ static int zend_jit_check_exception_undef_result(dasm_State **Dst, const zend_op
 	return zend_jit_check_exception(Dst);
 }
 
-static int zend_jit_trace_begin(dasm_State **Dst, uint32_t trace_num)
+static int zend_jit_trace_begin(dasm_State **Dst, uint32_t trace_num, zend_jit_trace_info *parent, uint32_t exit_num)
 {
+	zend_regset regset = ZEND_REGSET_SCRATCH;
+
+#if ZTS
+	if (1) {
+#else
+	if ((sizeof(void*) == 8 && !IS_32BIT(&EG(jit_trace_num)))) {
+#endif
+		/* assignment to EG(jit_trace_num) shouldn't clober CPU register used by deoptimizer */
+		if (parent) {
+			int i;
+			int parent_vars_count = parent->exit_info[exit_num].stack_size;
+			zend_jit_trace_stack *parent_stack =
+				parent->stack_map +
+				parent->exit_info[exit_num].stack_offset;
+
+			for (i = 0; i < parent_vars_count; i++) {
+				if (STACK_REG(parent_stack, i) != ZREG_NONE) {
+					if (STACK_REG(parent_stack, i) < ZREG_NUM) {
+						ZEND_REGSET_EXCL(regset, STACK_REG(parent_stack, i));
+					} else if (STACK_REG(parent_stack, i) == ZREG_ZVAL_COPY_R0) {
+						ZEND_REGSET_EXCL(regset, ZREG_R0);
+					}
+				}
+			}
+		}
+	}
+
 	current_trace_num = trace_num;
 
 	|	// EG(jit_trace_num) = trace_num;
-	|	MEM_OP2_1_ZTS mov, dword, executor_globals, jit_trace_num, trace_num, r0
+	if (regset == ZEND_REGSET_EMPTY) {
+		|	push r0
+		|	MEM_OP2_1_ZTS mov, dword, executor_globals, jit_trace_num, trace_num, r0
+		|	pop r0
+	} else {
+		zend_reg tmp = ZEND_REGSET_FIRST(regset);
+
+		|	MEM_OP2_1_ZTS mov, dword, executor_globals, jit_trace_num, trace_num, Ra(tmp)
+	}
 
 	return 1;
 }