Apply summary-based dead stripping to regular LTO modules with summaries.

If a regular LTO module has a summary index, then instead of linking
it into the combined regular LTO module right away, add it to the
combined summary index and associate it with a special module that
represents the combined regular LTO module.

Any such modules are linked during LTO::run(), at which time we use
the results of summary-based dead stripping to control whether to
link prevailing symbols.

Differential Revision: https://reviews.llvm.org/D33922

llvm-svn: 305482

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/IR/ModuleSummaryIndex.cpp b/llvm/lib/IR/ModuleSummaryIndex.cpp
index 9dd712f..721d4d47 100644
--- a/llvm/lib/IR/ModuleSummaryIndex.cpp
+++ b/llvm/lib/IR/ModuleSummaryIndex.cpp
@@ -56,3 +56,13 @@ ModuleSummaryIndex::getGlobalValueSummary(uint64_t ValueGUID,
   auto &Summary = VI.getSummaryList()[0];
   return Summary.get();
 }
+
+bool ModuleSummaryIndex::isGUIDLive(GlobalValue::GUID GUID) const {
+  auto VI = getValueInfo(GUID);
+  if (!VI)
+    return false;
+  for (auto &I : VI.getSummaryList())
+    if (isGlobalValueLive(I.get()))
+      return true;
+  return false;
+}