Add vendor snapshot modules

This implements four modules (static/shared/header libraries, and
binaries) for vendor snapshot. These modules will override source
modules if BOARD_VNDK_VERSION != current.

Bug: 65377115
Test: 1) VNDK_SNAPSHOT_BUILD_ARTIFACTS=true m dist vndk vendor-snapshot
Test: 2) install snapshot under source tree
Test: 3) set BOARD_VNDK_VERSION and boot cuttlefish
Change-Id: I24ddb4c3aa6abeab60bbfd31bcbd8753e2592dc5

1 files changed, 27 insertions, 0 deletions

diff --git a/cc/snapshot_utils.go b/cc/snapshot_utils.go
index 1c872c2c9..8f48f869b 100644
--- a/cc/snapshot_utils.go
+++ b/cc/snapshot_utils.go
@@ -31,6 +31,33 @@ type snapshotLibraryInterface interface {
 var _ snapshotLibraryInterface = (*prebuiltLibraryLinker)(nil)
 var _ snapshotLibraryInterface = (*libraryDecorator)(nil)
 
+type snapshotMap struct {
+	snapshots map[string]string
+}
+
+func newSnapshotMap() *snapshotMap {
+	return &snapshotMap{
+		snapshots: make(map[string]string),
+	}
+}
+
+func snapshotMapKey(name string, arch android.ArchType) string {
+	return name + ":" + arch.String()
+}
+
+// Adds a snapshot name for given module name and architecture.
+// e.g. add("libbase", X86, "libbase.vndk.29.x86")
+func (s *snapshotMap) add(name string, arch android.ArchType, snapshot string) {
+	s.snapshots[snapshotMapKey(name, arch)] = snapshot
+}
+
+// Returns snapshot name for given module name and architecture, if found.
+// e.g. get("libcutils", X86) => "libcutils.vndk.29.x86", true
+func (s *snapshotMap) get(name string, arch android.ArchType) (snapshot string, found bool) {
+	snapshot, found = s.snapshots[snapshotMapKey(name, arch)]
+	return snapshot, found
+}
+
 func exportedHeaders(ctx android.SingletonContext, l exportedFlagsProducer) android.Paths {
 	var ret android.Paths