type traceExperiment uint8

const (
	// traceNoExperiment indicates no experiment.
	traceNoExperiment traceExperiment = iota

	// traceExperimentAllocFree is an experiment to add alloc/free events to the trace.
	traceExperimentAllocFree
)

// Experimental events.
const (
	_ traceEv = 127 + iota

	// Experimental events for ExperimentAllocFree.

	// Experimental heap span events. IDs map reversibly to base addresses.

const (
	NSNAME = 8
	NSYM   = 50
	NREG   = 32 // number of general registers
	NFREG  = 32 // number of floating point registers
)

const (
	REG_R0 = obj.RBaseLOONG64 + iota // must be a multiple of 32
	REG_R1
	REG_R2
	REG_R3
	REG_R4
	REG_R5
	REG_R6
	REG_R7
	REG_R8
	REG_R9
	REG_R10
	REG_R11
	REG_R12
	REG_R13
	REG_R14
	REG_R15
	REG_R16
	REG_R17

type SchedReqs struct {
	Thread    Constraint
	Proc      Constraint
	Goroutine Constraint
}

// Constraint represents a various presence requirements.
type Constraint uint8

const (
	MustNotHave Constraint = iota
	MayHave
	MustHave
)

// UserGoReqs is a common requirement among events that are running
// or are close to running user code.

// and panic indicators, and the runtime, which turns them into more meaningful strings
// For best code generation, RF_DONE and RF_READY should be 0 and 1.
const (
	RF_DONE          = RF_State(iota) // body of loop has exited in a non-panic way
	RF_READY                          // body of loop has not exited yet, is not running  -- this is not a panic index

type Value struct {
	kind   ValueKind
	scalar uint64
}

// ValueKind is the type of a dynamically-typed value from a trace.
type ValueKind uint8

const (
	ValueBad ValueKind = iota
	ValueUint64
)

// Kind returns the ValueKind of the value.
//
// It represents the underlying structure of the value.
//
// New ValueKinds may be added in the future. Users of this type must be robust

// statuses.
type traceGoStatus uint8

const (
	traceGoBad traceGoStatus = iota
	traceGoRunnable
	traceGoRunning
	traceGoSyscall
	traceGoWaiting
)

// traceProcStatus is the status of a P.
//
// They mostly correspond to the various P statuses.
type traceProcStatus uint8

const (
	traceProcBad traceProcStatus = iota
	traceProcRunning
	traceProcIdle
	traceProcSyscall

}

var predeclaredConsts = [...]struct {
	name string
	kind BasicKind
	val  constant.Value
}{
	{"true", UntypedBool, constant.MakeBool(true)},
	{"false", UntypedBool, constant.MakeBool(false)},
	{"iota", UntypedInt, constant.MakeInt64(0)},
}

func defPredeclaredConsts() {
	for _, c := range predeclaredConsts {
		def(NewConst(nopos, nil, c.name, Typ[c.kind], c.val))
	}
}

func defPredeclaredNil() {

}

var predeclaredConsts = [...]struct {
	name string
	kind BasicKind
	val  constant.Value
}{
	{"true", UntypedBool, constant.MakeBool(true)},
	{"false", UntypedBool, constant.MakeBool(false)},
	{"iota", UntypedInt, constant.MakeInt64(0)},
}

func defPredeclaredConsts() {
	for _, c := range predeclaredConsts {
		def(NewConst(nopos, nil, c.name, Typ[c.kind], c.val))
	}
}

func defPredeclaredNil() {

// GoState represents the state of a goroutine.
//
// New GoStates may be added in the future. Users of this type must be robust
// to that possibility.
type GoState uint8

const (
	GoUndetermined GoState = iota // No information is known about the goroutine.
	GoNotExist                    // Goroutine does not exist.
	GoRunnable                    // Goroutine is runnable but not running.

	sema  uint32
}

// A Locker represents an object that can be locked and unlocked.
type Locker interface {
	Lock()
	Unlock()
}

const (
	mutexLocked = 1 << iota // mutex is locked
	mutexWoken
	mutexStarving
	mutexWaiterShift = iota

	// Mutex fairness.
	//
	// Mutex can be in 2 modes of operations: normal and starvation.
	// In normal mode waiters are queued in FIFO order, but a woken up waiter