From 773147ef7118a2d09966f6351d6da5ff07f6868c Mon Sep 17 00:00:00 2001
From: Marc Vertes <mvertes@free.fr>
Date: Fri, 8 Nov 2019 00:34:04 +0100
Subject: [PATCH] fix: properly align atomic counters

---
 interp/interp.go | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/interp/interp.go b/interp/interp.go
index bb35a106a..8fe3de84b 100644
--- a/interp/interp.go
+++ b/interp/interp.go
@@ -53,11 +53,14 @@ type receiver struct {
 
 // frame contains values for the current execution level (a function context)
 type frame struct {
+	// id is an atomic counter used for cancellation, only access
+	// via newFrame/runid/setrunid/clone.
+	// Located at start of struct to ensure proper aligment.
+	id uint64
+
 	anc  *frame          // ancestor frame (global space)
 	data []reflect.Value // values
 
-	id uint64 // for cancellation, only access via newFrame/runid/setrunid/clone.
-
 	mutex     sync.RWMutex
 	deferred  [][]reflect.Value  // defer stack
 	recovered interface{}        // to handle panic recover
@@ -108,6 +111,12 @@ type opt struct {
 
 // Interpreter contains global resources and state
 type Interpreter struct {
+	// id is an atomic counter counter used for run cancellation,
+	// only accessed via runid/stop
+	// Located at start of struct to ensure proper alignment on 32 bit
+	// architectures.
+	id uint64
+
 	Name string // program name
 
 	opt                        // user settable options
@@ -117,8 +126,6 @@ type Interpreter struct {
 	binPkg     Exports         // binary packages used in interpreter, indexed by path
 	rdir       map[string]bool // for src import cycle detection
 
-	id uint64 // for cancellation, only accessed via runid/stop
-
 	mutex    sync.RWMutex
 	frame    *frame            // program data storage during execution
 	universe *scope            // interpreter global level scope