[LinkerWrapper] Fix use of string savers and correctly pass bitcode libraries

This patch removes some uses of string savers that are no-longer needed.
We also create a new string saver when linking bitcode files. It seems
that occasionally the symbol string references can go out of scope when
they are added to the LTO input so we need to save these names that are
used for symbol resolution. Additionally, a previous patch added new
logic for handling bitcode libraries, but failed to actually add them to
the input. This bug has been fixed.

Fixes llvm#56445

Reviewed By: ye-luo

Differential Revision: https://reviews.llvm.org/D129383

Author: jhuber6

clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp

@@ -525,17 +525,15 @@ fatbinary(ArrayRef<std::pair<StringRef, StringRef>> InputFiles,
   if (!TempFileOrErr)
     return TempFileOrErr.takeError();
 
-  BumpPtrAllocator Alloc;
-  StringSaver Saver(Alloc);
-
   SmallVector<StringRef, 16> CmdArgs;
   CmdArgs.push_back(*FatBinaryPath);
   CmdArgs.push_back(Triple.isArch64Bit() ? "-64" : "-32");
   CmdArgs.push_back("--create");
   CmdArgs.push_back(*TempFileOrErr);
   for (const auto &FileAndArch : InputFiles)
-    CmdArgs.push_back(Saver.save("--image=profile=" + std::get<1>(FileAndArch) +
-                                 ",file=" + std::get<0>(FileAndArch)));
+    CmdArgs.push_back(
+        Args.MakeArgString("--image=profile=" + std::get<1>(FileAndArch) +
+                           ",file=" + std::get<0>(FileAndArch)));
 
   if (Error Err = executeCommands(*FatBinaryPath, CmdArgs))
     return std::move(Err);
@@ -808,6 +806,8 @@ Error linkBitcodeFiles(SmallVectorImpl<OffloadFile> &InputFiles,
   SmallVector<OffloadFile, 4> BitcodeInputFiles;
   DenseSet<StringRef> UsedInRegularObj;
   DenseSet<StringRef> UsedInSharedLib;
+  BumpPtrAllocator Alloc;
+  StringSaver Saver(Alloc);
 
   // Search for bitcode files in the input and create an LTO input file. If it
   // is not a bitcode file, scan its symbol table for symbols we need to save.
@@ -844,9 +844,9 @@ Error linkBitcodeFiles(SmallVectorImpl<OffloadFile> &InputFiles,
 
         // Record if we've seen these symbols in any object or shared libraries.
         if ((*ObjFile)->isRelocatableObject())
-          UsedInRegularObj.insert(*Name);
+          UsedInRegularObj.insert(Saver.save(*Name));
         else
-          UsedInSharedLib.insert(*Name);
+          UsedInSharedLib.insert(Saver.save(*Name));
       }
       continue;
     }
@@ -908,7 +908,8 @@ Error linkBitcodeFiles(SmallVectorImpl<OffloadFile> &InputFiles,
       // We will use this as the prevailing symbol definition in LTO unless
       // it is undefined or another definition has already been used.
       Res.Prevailing =
-          !Sym.isUndefined() && PrevailingSymbols.insert(Sym.getName()).second;
+          !Sym.isUndefined() &&
+          PrevailingSymbols.insert(Saver.save(Sym.getName())).second;
 
       // We need LTO to preseve the following global symbols:
       // 1) Symbols used in regular objects.
@@ -1193,8 +1194,6 @@ linkAndWrapDeviceFiles(SmallVectorImpl<OffloadFile> &LinkerInputFiles,
     InputsForTarget[File].emplace_back(std::move(File));
   LinkerInputFiles.clear();
 
-  BumpPtrAllocator Alloc;
-  UniqueStringSaver Saver(Alloc);
   DenseMap<OffloadKind, SmallVector<OffloadingImage, 2>> Images;
   for (auto &InputForTarget : InputsForTarget) {
     SmallVector<OffloadFile, 4> &Input = InputForTarget.getSecond();
@@ -1395,6 +1394,7 @@ int main(int Argc, char **Argv) {
     auto FileOrErr = getInputBitcodeLibrary(Library);
     if (!FileOrErr)
       reportError(FileOrErr.takeError());
+    InputFiles.push_back(std::move(*FileOrErr));
   }
 
   DenseSet<OffloadFile::TargetID> IsTargetUsed;