// package is nil for objects in universe scope
	if a == nil || b == nil {
		return a == b
	}
	// a != nil && b != nil
	return a.path == b.path
}

// An ifacePair is a node in a stack of interface type pairs compared for identity.
type ifacePair struct {
	x, y *Interface
	prev *ifacePair
}

func (p *ifacePair) identical(q *ifacePair) bool {

	appendWalkStmt(init, ir.NewAssignStmt(base.Pos, vauto, a))

	if vstat != nil && n.Prealloc == nil && n.Esc() != ir.EscNone {
		// If we allocated on the heap with ONEW, copy the static to the
		// heap (4). We skip this for stack temporaries, because
		// initStackTemp already handled the copy.
		a = ir.NewStarExpr(base.Pos, vauto)
		appendWalkStmt(init, ir.NewAssignStmt(base.Pos, a, vstat))
	}

	// put dynamics into array (5)

// NewNat returns a new nat with a size of zero, just like new(Nat), but with
// the preallocated capacity to hold a number of up to preallocTarget bits.
// NewNat inlines, so the allocation can live on the stack.
func NewNat() *Nat {
	limbs := make([]uint, 0, preallocLimbs)
	return &Nat{limbs}
}

// expand expands x to n limbs, leaving its value unchanged.
func (x *Nat) expand(n int) *Nat {
	if len(x.limbs) > n {

// stack grows as part of starting the deferred function. It calls Goexit at various
// stack depths, forcing the deferred function (with >4kB of args) to be run at
// the bottom of the stack. The goal is to find a stack depth less than 4kB from
// the end of the stack. Each trial runs in a different goroutine so that an earlier
// stack growth does not invalidate a later attempt.

	// Set the stack bounds to match the current stack. If we don't
	// actually know how big the stack is, like we don't know how big any
	// scheduling stack is, but we assume there's at least 32 kB. If we
	// can get a more accurate stack bound from pthread, use that, provided
	// it actually contains SP..
	g0.stack.hi = sp + 1024
	g0.stack.lo = sp - 32*1024
	if !signal && _cgo_getstackbound != nil {

			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		type event struct {
			WhenString string
			Elapsed    time.Duration
			Goroutine  trace.GoID
			What       string
			// TODO: include stack trace of creation time
		}
		type task struct {
			WhenString string
			ID         trace.TaskID
			Duration   time.Duration
			Complete   bool
			Events     []event

// alternate signal stack. If the alternate signal stack is not set
// for the thread (the normal case) then set the alternate signal
// stack to the gsignal stack. If the alternate signal stack is set
// for the thread (the case when a non-Go thread sets the alternate
// signal stack and then calls a Go function) then set the gsignal
// stack to the alternate signal stack. We also set the alternate

// license that can be found in the LICENSE file.

// Trace stack table and acquisition.

package runtime

import (
	"internal/abi"
	"internal/goarch"
	"unsafe"
)

const (
	// Maximum number of PCs in a single stack trace.
	// Since events contain only stack id rather than whole stack trace,
	// we can allow quite large values here.
	traceStackSize = 128

//
// //go:uintptrkeepalive because the uintptr argument may be converted pointers
// that need to be kept alive in the caller.
//
// //go:nosplit because stack copying does not account for uintptrkeepalive, so
// the stack must not grow. Stack copying cannot blindly assume that all
// uintptr arguments are pointers, because some values may look like pointers,

// its value is looked up in the type argument list of the instantiated
// (enclosing) type, if it exists. Otherwise the type parameter must be from
// an enclosing function and can be ignored.
// The nest list describes the stack (the "nest in memory") of types which
// contain (or embed in the case of interfaces) other types. For instance, a
// struct named S which contains a field of named type F contains (the memory