[llvm] Unittests and usability for BitstreamWriter incremental flushing (PR #92983)

[Teresa Johnson via llvm-commits]

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@@ -5055,13 +5055,13 @@ void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
   Triple TT(M.getTargetTriple());
   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
-
-  BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
-  Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
-                     ModHash);
-  Writer.writeSymtab();
-  Writer.writeStrtab();
-
+  {
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teresajohnson wrote:

Why is this change needed? Is it to trigger the destructor earlier? Why is that needed when the rest of the buffer is written to Out just below here at line 5070?

https://github.com/llvm/llvm-project/pull/92983