From 00ee5edc0de59ad90623144730252b3ffc276946 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Mon, 17 Oct 2016 19:25:08 +0000
Subject: [PATCH] Avoid using getComdatSymbolTable.

This is not particularly efficient, but does avoid exposing Comdat*
out of LTO.h.

I will send a patch for review with a more efficient interface that
should map nicely to a bitcode symbol table.

llvm-svn: 284413
---
 lld/ELF/InputFiles.cpp | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 9c88d5f..af0f30a 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -693,7 +693,8 @@ static uint8_t mapVisibility(GlobalValue::VisibilityTypes GvVisibility) {
 }
 
 template <class ELFT>
-static Symbol *createBitcodeSymbol(const DenseSet<StringRef> &KeptComdats,
+static Symbol *createBitcodeSymbol(DenseSet<StringRef> &KeptComdats,
+                                   DenseSet<StringRef> &ComdatGroups,
                                    const lto::InputFile::Symbol &ObjSym,
                                    StringSaver &Saver, BitcodeFile *F) {
   StringRef NameRef = Saver.save(ObjSym.getName());
@@ -705,9 +706,19 @@ static Symbol *createBitcodeSymbol(const DenseSet<StringRef> &KeptComdats,
   bool CanOmitFromDynSym = ObjSym.canBeOmittedFromSymbolTable();
 
   StringRef C = check(ObjSym.getComdat());
-  if (!C.empty() && !KeptComdats.count(C))
-    return Symtab<ELFT>::X->addUndefined(NameRef, Binding, Visibility, Type,
-                                         CanOmitFromDynSym, F);
+  if (!C.empty()) {
+    bool Keep = KeptComdats.count(C);
+    if (!Keep) {
+      StringRef N = Saver.save(C);
+      if (ComdatGroups.insert(N).second) {
+        Keep = true;
+        KeptComdats.insert(C);
+      }
+    }
+    if (!Keep)
+      return Symtab<ELFT>::X->addUndefined(NameRef, Binding, Visibility, Type,
+                                           CanOmitFromDynSym, F);
+}
 
   if (Flags & BasicSymbolRef::SF_Undefined)
     return Symtab<ELFT>::X->addUndefined(NameRef, Binding, Visibility, Type,
@@ -737,15 +748,9 @@ void BitcodeFile::parse(DenseSet<StringRef> &ComdatGroups) {
       MB.getBuffer(), Saver.save(ArchiveName + MB.getBufferIdentifier() +
                                  utostr(OffsetInArchive)))));
   DenseSet<StringRef> KeptComdats;
-  for (const auto &P : Obj->getComdatSymbolTable()) {
-    StringRef N = Saver.save(P.first());
-    if (ComdatGroups.insert(N).second)
-      KeptComdats.insert(N);
-  }
-
   for (const lto::InputFile::Symbol &ObjSym : Obj->symbols())
-    Symbols.push_back(
-        createBitcodeSymbol<ELFT>(KeptComdats, ObjSym, Saver, this));
+    Symbols.push_back(createBitcodeSymbol<ELFT>(KeptComdats, ComdatGroups,
+                                                ObjSym, Saver, this));
 }
 
 template <template <class> class T>
-- 
2.7.4