run init in a goroutine

src/runtime/gc_conservative.go

@@ -180,7 +180,7 @@ func (b gcBlock) unmark() {
 // No memory may be allocated before this is called. That means the runtime and
 // any packages the runtime depends upon may not allocate memory during package
 // initialization.
-func init() {
+func initHeap() {
 	totalSize := heapEnd - heapStart
 
 	// Allocate some memory to keep 2 bits of information about every block.

src/runtime/gc_leaking.go

@@ -45,3 +45,7 @@ func KeepAlive(x interface{}) {
 func SetFinalizer(obj interface{}, finalizer interface{}) {
 	// Unimplemented.
 }
+
+func initHeap() {
+	// Nothing to initialize.
+}

src/runtime/gc_none.go

@@ -27,3 +27,7 @@ func KeepAlive(x interface{}) {
 func SetFinalizer(obj interface{}, finalizer interface{}) {
 	// Unimplemented.
 }
+
+func initHeap() {
+	// Nothing to initialize.
+}

src/runtime/runtime_unix.go

@@ -26,10 +26,7 @@ func clock_gettime(clk_id int32, ts *timespec)
 
 const heapSize = 1 * 1024 * 1024 // 1MB to start
 
-var (
+var heapStart, heapEnd uintptr
-	heapStart = uintptr(malloc(heapSize))
-	heapEnd   = heapStart + heapSize
-)
 
 type timeUnit int64
 
@@ -50,6 +47,9 @@ func postinit() {}
 // Entry point for Go. Initialize all packages and call main.main().
 //go:export main
 func main() int {
+	heapStart = uintptr(malloc(heapSize))
+	heapEnd = heapStart + heapSize
+
 	run()
 
 	// For libc compatibility.

src/runtime/runtime_wasm.go

@@ -22,6 +22,10 @@ func postinit() {}
 
 //export _start
 func _start() {
+	// These need to be initialized early so that the heap can be initialized.
+	heapStart = uintptr(unsafe.Pointer(&heapStartSymbol))
+	heapEnd = uintptr(wasm_memory_size(0) * wasmPageSize)
+
 	run()
 }
 

src/runtime/scheduler_any.go

@@ -14,9 +14,10 @@ func sleep(duration int64) {
 // run is called by the program entry point to execute the go program.
 // With a scheduler, init and the main function are invoked in a goroutine before starting the scheduler.
 func run() {
-	initAll()
+	initHeap()
-	postinit()
 	go func() {
+		initAll()
+		postinit()
 		callMain()
 	}()
 	scheduler()

src/runtime/scheduler_none.go

@@ -16,6 +16,7 @@ func getSystemStackPointer() uintptr {
 // run is called by the program entry point to execute the go program.
 // With the "none" scheduler, init and the main function are invoked directly.
 func run() {
+	initHeap()
 	initAll()
 	postinit()
 	callMain()