| // 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/linux' 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/asan", | |
| "internal/byteorder", | |
| "internal/coverage/rtcov", | |
| "internal/cpu", | |
| "internal/bytealg", | |
| "internal/goarch", | |
| "internal/abi", | |
| "internal/chacha8rand", | |
| "internal/godebugs", | |
| "internal/goexperiment", | |
| "internal/goos", | |
| "internal/msan", | |
| "internal/profilerecord", | |
| "internal/race", | |
| "internal/runtime/atomic", | |
| "internal/runtime/exithook", | |
| "internal/runtime/gc", | |
| "internal/runtime/math", | |
| "internal/runtime/sys", | |
| "internal/runtime/maps", | |
| "internal/runtime/syscall/linux", | |
| "internal/runtime/syscall/windows", | |
| "internal/runtime/cgroup", | |
| "internal/strconv", | |
| "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 { | |
| for k, p := range rtPkgs { | |
| if p == pkgpath { | |
| return (0 - k) - 2 | |
| } | |
| } | |
| return NotHardCoded | |
| } | |