1 files changed, 72 insertions, 0 deletions
diff --git a/src/runtime/covermeta.go b/src/runtime/covermeta.go
new file mode 100644
index 0000000..54ef42a
--- /dev/null
+++ b/src/runtime/covermeta.go
@@ -0,0 +1,72 @@
+// 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 runtime
+
+import (
+	"internal/coverage/rtcov"
+	"unsafe"
+)
+
+// covMeta is the top-level container for bits of state related to
+// code coverage meta-data in the runtime.
+var covMeta struct {
+	// metaList contains the list of currently registered meta-data
+	// blobs for the running program.
+	metaList []rtcov.CovMetaBlob
+
+	// pkgMap records mappings from hard-coded package IDs to
+	// slots in the covMetaList above.
+	pkgMap map[int]int
+
+	// Set to true if we discover a package mapping glitch.
+	hardCodedListNeedsUpdating bool
+}
+
+// addCovMeta is invoked during package "init" functions by the
+// compiler when compiling for coverage instrumentation; here 'p' is a
+// meta-data blob of length 'dlen' for the package in question, 'hash'
+// is a compiler-computed md5.sum for the blob, 'pkpath' is the
+// package path, 'pkid' is the hard-coded ID that the compiler is
+// using for the package (or -1 if the compiler doesn't think a
+// hard-coded ID is needed), and 'cmode'/'cgran' are the coverage
+// counter mode and granularity requested by the user. Return value is
+// the ID for the package for use by the package code itself.
+func addCovMeta(p unsafe.Pointer, dlen uint32, hash [16]byte, pkpath string, pkid int, cmode uint8, cgran uint8) uint32 {
+	slot := len(covMeta.metaList)
+	covMeta.metaList = append(covMeta.metaList,
+		rtcov.CovMetaBlob{
+			P:                  (*byte)(p),
+			Len:                dlen,
+			Hash:               hash,
+			PkgPath:            pkpath,
+			PkgID:              pkid,
+			CounterMode:        cmode,
+			CounterGranularity: cgran,
+		})
+	if pkid != -1 {
+		if covMeta.pkgMap == nil {
+			covMeta.pkgMap = make(map[int]int)
+		}
+		if _, ok := covMeta.pkgMap[pkid]; ok {
+			throw("runtime.addCovMeta: coverage package map collision")
+		}
+		// Record the real slot (position on meta-list) for this
+		// package; we'll use the map to fix things up later on.
+		covMeta.pkgMap[pkid] = slot
+	}
+
+	// ID zero is reserved as invalid.
+	return uint32(slot + 1)
+}
+
+//go:linkname runtime_coverage_getCovMetaList runtime/coverage.getCovMetaList
+func runtime_coverage_getCovMetaList() []rtcov.CovMetaBlob {
+	return covMeta.metaList
+}
+
+//go:linkname runtime_coverage_getCovPkgMap runtime/coverage.getCovPkgMap
+func runtime_coverage_getCovPkgMap() map[int]int {
+	return covMeta.pkgMap
+}