Add ThinLTO support for py_binary targets.

Builds of py_binary targets were failing with --features=thin_lto
during the link because the C++ source files were compiled into
bitcode, but the link (which is set up by GooglePythonSemantics.java) did
not have support for ThinLTO actions and attempted to do a native link of
the bitcode objects.

--
PiperOrigin-RevId: 150201765
MOS_MIGRATED_REVID=150201765

1 files changed, 1 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
index 22201abdc4..ac15e13c76 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
@@ -289,6 +289,7 @@ public class CppLinkActionBuilder {
     this.nonCodeInputs.addAll(linkContext.nonCodeInputs);
     this.libraries.addTransitive(linkContext.libraries);
     this.crosstoolInputs = linkContext.crosstoolInputs;
+    this.ltoBitcodeFiles.addAll(linkContext.ltoBitcodeFiles);
     this.runtimeMiddleman = linkContext.runtimeMiddleman;
     this.runtimeInputs = linkContext.runtimeInputs;
     this.runtimeType = linkContext.runtimeType;