packer-cn/vendor/honnef.co/go/tools/functions/stub.go

33 lines
845 B
Go

package functions
import (
"honnef.co/go/tools/ir"
)
// IsStub reports whether a function is a stub. A function is
// considered a stub if it has no instructions or if all it does is
// return a constant value.
func IsStub(fn *ir.Function) bool {
for _, b := range fn.Blocks {
for _, instr := range b.Instrs {
switch instr.(type) {
case *ir.Const:
// const naturally has no side-effects
case *ir.Panic:
// panic is a stub if it only uses constants
case *ir.Return:
// return is a stub if it only uses constants
case *ir.DebugRef:
case *ir.Jump:
// if there are no disallowed instructions, then we're
// only jumping to the exit block (or possibly
// somewhere else that's stubby?)
default:
// all other instructions are assumed to do actual work
return false
}
}
}
return true
}