Merge "Add option to emit ThinLTO indexes and imports for MLGO training" into main am: bc9d35168c

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2812353

Change-Id: Id79172f6ad0bb0bb87da0511de0ee70034f8b835
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/cc/lto.go b/cc/lto.go
index d48be14..20e4f24 100644
--- a/cc/lto.go
+++ b/cc/lto.go
@@ -147,6 +147,12 @@
 			}
 		}
 
+		// For ML training
+		if ctx.Config().IsEnvTrue("THINLTO_EMIT_INDEXES_AND_IMPORTS") {
+			ltoLdFlags = append(ltoLdFlags, "-Wl,--save-temps=import")
+			ltoLdFlags = append(ltoLdFlags, "-Wl,--thinlto-emit-index-files")
+		}
+
 		flags.Local.CFlags = append(flags.Local.CFlags, ltoCFlags...)
 		flags.Local.AsFlags = append(flags.Local.AsFlags, ltoCFlags...)
 		flags.Local.LdFlags = append(flags.Local.LdFlags, ltoCFlags...)