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, 4 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 9c4316f..bd01902 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -964,11 +964,11 @@ Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
   if (!BMsOrErr)
     return BMsOrErr.takeError();
 
-  // The bitcode file may contain multiple modules, we want the one with a
-  // summary.
+  // The bitcode file may contain multiple modules, we want the one that is
+  // marked as being the ThinLTO module.
   for (BitcodeModule &BM : *BMsOrErr) {
-    Expected<bool> HasSummary = BM.hasSummary();
-    if (HasSummary && *HasSummary)
+    Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
+    if (LTOInfo && LTOInfo->IsThinLTO)
       return BM;
   }