From 87db4ffadac291bc878cb892e05601610ca68ef5 Mon Sep 17 00:00:00 2001 From: Than McIntosh Date: Mon, 11 Oct 2021 07:34:20 -0400 Subject: runtime/coverage: runtime routines to emit coverage data This patch fleshes out the runtime support for emitting coverage data at the end of a run of an instrumented binary. Data is emitted in the form of a pair of files, a meta-out-file and counter-data-outfile, each written to the dir GOCOVERDIR. The meta-out-file is emitted only if required; no need to emit again if an existing meta-data file with the same hash and length is present. Updates #51430. Change-Id: I59d20a4b8c05910c933ee29527972f8e401b1685 Reviewed-on: https://go-review.googlesource.com/c/go/+/355451 Reviewed-by: Michael Knyszek TryBot-Result: Gopher Robot Run-TryBot: Than McIntosh --- src/runtime/coverage/hooks.go | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 src/runtime/coverage/hooks.go (limited to 'src/runtime/coverage/hooks.go') diff --git a/src/runtime/coverage/hooks.go b/src/runtime/coverage/hooks.go new file mode 100644 index 0000000000..a9fbf9d7dd --- /dev/null +++ b/src/runtime/coverage/hooks.go @@ -0,0 +1,42 @@ +// 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 + +import _ "unsafe" + +// initHook is invoked from the main package "init" routine in +// programs built with "-cover". This function is intended to be +// called only by the compiler. +// +// If 'istest' is false, it indicates we're building a regular program +// ("go build -cover ..."), in which case we immediately try to write +// out the meta-data file, and register emitCounterData as an exit +// hook. +// +// If 'istest' is true (indicating that the program in question is a +// Go test binary), then we tentatively queue up both emitMetaData and +// emitCounterData as exit hooks. In the normal case (e.g. regular "go +// test -cover" run) the testmain.go boilerplate will run at the end +// of the test, write out the coverage percentage, and then invoke +// markProfileEmitted() to indicate that no more work needs to be +// done. If however that call is never made, this is a sign that the +// test binary is being used as a replacement binary for the tool +// being tested, hence we do want to run exit hooks when the program +// terminates. +func initHook(istest bool) { + // Note: hooks are run in reverse registration order, so + // register the counter data hook before the meta-data hook + // (in the case where two hooks are needed). + runOnNonZeroExit := true + runtime_addExitHook(emitCounterData, runOnNonZeroExit) + if istest { + runtime_addExitHook(emitMetaData, runOnNonZeroExit) + } else { + emitMetaData() + } +} + +//go:linkname runtime_addExitHook runtime.addExitHook +func runtime_addExitHook(f func(), runOnNonZeroExit bool) -- cgit v1.2.1