[opt] Initialize WriteBitcode pass.

[Meinersbur]

Summary

Probably due to a change of how some pass initializes its dependency, the -write-bitcode pass (BitcodeWriterPass.cpp) is not initialized in opt and therefore not available in the pass list anymore.

Explicitly call initializeWriteBitcodePassPass() to make it available again in opt.

Alternatively, is there an initializeBitcode{Reader/Writer}() function that initializes all passes from the Bitcode lib?

[MatzeB]

Seems obvious, LGTM.

Alternatively, is there an initializeBitcode{Reader/Writer}() function that initializes all passes from the Bitcode lib?

The reader and writer are in separate libraries, aren't they?

[Meinersbur]

In D39223#905326, @MatzeB wrote:

Alternatively, is there an initializeBitcode{Reader/Writer}() function that initializes all passes from the Bitcode lib?

The reader and writer are in separate libraries, aren't they?

Yes, they are. WriteBitcodePass is the only pass in these libraries (None in LLVMBitReader). I was speculating because other libraries have a common initializeXYZ().

tools/opt/opt.cpp

   initializeCountingFunctionInserterPass(Registry);
   initializeUnreachableBlockElimLegacyPassPass(Registry);
   initializeExpandReductionsPass(Registry);
+  initializeWriteBitcodePassPass(Registry);
 
 #ifdef LINK_POLLY_INTO_TOOLS
   polly::initializePollyPasses(Registry);