[ThinLTO] Allow importing of multiple symbols with same GUID

Summary:
The is the clang side of the fix in D55047, to handle the case where
two different modules have local variables with the same GUID because
they had the same source file name at compilation time. Allow multiple
symbols with the same GUID to be imported, and test that this case works
with the distributed backend path.

Depends on D55047.

Reviewers: evgeny777

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D55048

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@347887 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 9 deletions

diff --git a/lib/CodeGen/BackendUtil.cpp b/lib/CodeGen/BackendUtil.cpp
index 61c68d117e..f746bc2f88 100644
--- a/lib/CodeGen/BackendUtil.cpp
+++ b/lib/CodeGen/BackendUtil.cpp
@@ -1155,15 +1155,14 @@ static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
       continue;
 
     auto GUID = GlobalList.first;
-    assert(GlobalList.second.SummaryList.size() == 1 &&
-           "Expected individual combined index to have one summary per GUID");
-    auto &Summary = GlobalList.second.SummaryList[0];
-    // Skip the summaries for the importing module. These are included to
-    // e.g. record required linkage changes.
-    if (Summary->modulePath() == M->getModuleIdentifier())
-      continue;
-    // Add an entry to provoke importing by thinBackend.
-    ImportList[Summary->modulePath()].insert(GUID);
+    for (auto &Summary : GlobalList.second.SummaryList) {
+      // Skip the summaries for the importing module. These are included to
+      // e.g. record required linkage changes.
+      if (Summary->modulePath() == M->getModuleIdentifier())
+        continue;
+      // Add an entry to provoke importing by thinBackend.
+      ImportList[Summary->modulePath()].insert(GUID);
+    }
   }
 
   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;