From b4131e297e18fde119f6f461b3e622218166b009 Mon Sep 17 00:00:00 2001

From: Josh Stone <jistone@redhat.com>

Date: Fri, 26 Apr 2019 08:58:14 -0700

Subject: [PATCH] Limit internalization in LLVM 8 ThinLTO

---

 src/rustllvm/PassWrapper.cpp | 5 ++++-

 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/rustllvm/PassWrapper.cpp b/src/rustllvm/PassWrapper.cpp

index 319c66a21f17..0ebef82d3768 100644

--- a/src/rustllvm/PassWrapper.cpp

+++ b/src/rustllvm/PassWrapper.cpp

@@ -873,8 +873,11 @@ LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules,

     return PrevailingType::Unknown;

   };

 #if LLVM_VERSION_GE(8, 0)

+  // We don't have a complete picture in our use of ThinLTO, just our immediate

+  // crate, so we need `ImportEnabled = false` to limit internalization.

+  // Otherwise, we sometimes lose `static` values -- see #60184.

   computeDeadSymbolsWithConstProp(Ret->Index, Ret->GUIDPreservedSymbols,

-                                  deadIsPrevailing, /* ImportEnabled = */ true);

+                                  deadIsPrevailing, /* ImportEnabled = */ false);

 #else

   computeDeadSymbols(Ret->Index, Ret->GUIDPreservedSymbols, deadIsPrevailing);

 #endif

-- 

2.20.1