// Copyright 2022 The Go Authors. All rights reserved.

// Use of this source code is governed by a BSD-style

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

package coverage

// Building the runtime package with coverage instrumentation enabled

// is tricky. For all other packages, you can be guaranteed that

// the package init function is run before any functions are executed,

// but this invariant is not maintained for packages such as "runtime",

// "internal/cpu", etc. To handle this, hard-code the package ID for

// the set of packages whose functions may be running before the

// init function of the package is complete.

//

// Hardcoding is unfortunate because it means that the tool that does

// coverage instrumentation has to keep a list of runtime packages,

// meaning that if someone makes changes to the pkg "runtime"

// dependencies, unexpected behavior will result for coverage builds.

// The coverage runtime will detect and report the unexpected

// behavior; look for an error of this form:

//

// internal error in coverage meta-data tracking:

// list of hard-coded runtime package IDs needs revising.

// registered list:

// slot: 0 path='internal/cpu' hard-coded id: 1

// slot: 1 path='internal/goarch' hard-coded id: 2

// slot: 2 path='internal/runtime/atomic' hard-coded id: 3

// slot: 3 path='internal/goos'

// slot: 4 path='internal/runtime/sys' hard-coded id: 5

// slot: 5 path='internal/abi' hard-coded id: 4

// slot: 6 path='internal/runtime/math' hard-coded id: 6

// slot: 7 path='internal/bytealg' hard-coded id: 7

// slot: 8 path='internal/goexperiment'

// slot: 9 path='internal/runtime/syscall' hard-coded id: 8

// slot: 10 path='runtime' hard-coded id: 9

// fatal error: runtime.addCovMeta

//

// For the error above, the hard-coded list is missing "internal/goos"

// and "internal/goexperiment" ; the developer in question will need

// to copy the list above into "rtPkgs" below.

//

// Note: this strategy assumes that the list of dependencies of

// package runtime is fixed, and doesn't vary depending on OS/arch. If

// this were to be the case, we would need a table of some sort below

// as opposed to a fixed list.

var rtPkgs = [...]string{

"internal/cpu",

"internal/goarch",

"internal/runtime/atomic",

"internal/goos",

"internal/chacha8rand",

"internal/runtime/sys",

"internal/abi",

"internal/runtime/maps",

"internal/runtime/math",

"internal/bytealg",

"internal/goexperiment",

"internal/runtime/syscall",

"internal/stringslite",

"runtime",

}

// Scoping note: the constants and apis in this file are internal

// only, not expected to ever be exposed outside of the runtime (unlike

// other coverage file formats and APIs, which will likely be shared

// at some point).

// NotHardCoded is a package pseudo-ID indicating that a given package

// is not part of the runtime and doesn't require a hard-coded ID.

const NotHardCoded = -1

// HardCodedPkgID returns the hard-coded ID for the specified package

// path, or -1 if we don't use a hard-coded ID. Hard-coded IDs start

// at -2 and decrease as we go down the list.

func HardCodedPkgID(pkgpath string) int {

}