LowerTypeTests: Propagate symver directives

Summary:
This change fixes https://crbug.com/834474, a build failure caused by
LowerTypeTests not preserving .symver symbol versioning directives for
exported functions. Emit symver information to ThinLTO summary data and
then propagate symver directives for exported functions to the merged
module.

Emitting symver information to the summaries increases the size of
intermediate build artifacts for a Chromium build by less than 0.2%.

Reviewers: pcc

Reviewed By: pcc

Subscribers: tejohnson, mehdi_amini, eraman, llvm-commits, eugenis, kcc

Differential Revision: https://reviews.llvm.org/D45798

llvm-svn: 330387

1 files changed, 10 insertions, 4 deletions

diff --git a/llvm/lib/Object/RecordStreamer.h b/llvm/lib/Object/RecordStreamer.h
index 60b2d3ec3e8..13eac028a28 100644
--- a/llvm/lib/Object/RecordStreamer.h
+++ b/llvm/lib/Object/RecordStreamer.h
@@ -47,10 +47,6 @@ private:
 public:
   RecordStreamer(MCContext &Context, const Module &M);
 
-  using const_iterator = StringMap<State>::const_iterator;
-
-  const_iterator begin();
-  const_iterator end();
   void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
                        bool) override;
   void EmitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
@@ -63,9 +59,19 @@ public:
   /// Record .symver aliases for later processing.
   void emitELFSymverDirective(StringRef AliasName,
                               const MCSymbol *Aliasee) override;
+
   // Emit ELF .symver aliases and ensure they have the same binding as the
   // defined symbol they alias with.
   void flushSymverDirectives();
+
+  // Symbols iterators
+  using const_iterator = StringMap<State>::const_iterator;
+  const_iterator begin();
+  const_iterator end();
+
+  // SymverAliasMap iterators
+  using const_symver_iterator = decltype(SymverAliasMap)::const_iterator;
+  iterator_range<const_symver_iterator> symverAliases();
 };
 
 } // end namespace llvm