Issue with controlflow of SelectStmt

[KamrulHassan (Md Kamrul Hassan)]

I have been using the cfg package to create cfg of go programs. While working with SelectStmt, I’ve found the cfg a bit odd. For example:

func Foo() bool {
   	var c1, c2 chan int
   	select {
   	case c1 <- 1:
		fmt.Print("c1 <- 1")
   	case c1 <- 3:
		fmt.Print("c1 <- 3")
   	case <-c2:
   	default:
		fmt.Print("default")
   	}
   	return true
}

For this code snippet, CFG is generated like below:

.0: # entry
c1, c2 chan int
c1 ← 1
c1 ← 3
<-c2
succs: 2 3

.1: # select.done
return true

.2: # select.body
fmt.Print(“c1 ← 1”)
succs: 1

.3: # select.next
succs: 4 5

.4: # select.body
fmt.Print(“c1 ← 3”)
succs: 1

.5: # select.next
succs: 6 7

.6: # select.body
succs: 1

.7: # select.next
fmt.Print(“default”)
succs: 1

.8: # unreachable.return

Here in block 0, We can find all the Comms are present sequentially, suggesting CommClauses are evaluated sequentially which is similar to switch. I was expecting something like the following. There should be multiple paths from block 0 (instead of true,false path):

.0: # entry
msg []string
c1, c2 chan int
succs: 1, 2, 3, 4

.1 # select.body
c1 ← 1
fmt.Print(“c1 ← 1”)
succs : 5

.2 # select.body
c3 ← 1
fmt.Print(“c1 ← 3”)
succs : 5

.3 # select.body
← c2
succs : 5

.4 # select.body
fmt.Print(“default”)
succs : 5

.5 # select.done
return true

Am I missing Something?