VoidCallRemoval: does not support InvokeInst

[stanislaw]

This line:

if (instruction->getOpcode() != llvm::Instruction::Call &&

prevents the code that follows it to be executed for the InvokeInst instructions.

Changing it to

  if (instruction->getOpcode() != llvm::Instruction::Call &&
      instruction->getOpcode() != llvm::Instruction::Invoke) {
    return false;
  }

is a valid step but then LLVM compilation of the mutated module crashes on the well-known chunk of code:

      MCContext *Ctx;
      if (TM.addPassesToEmitMC(PM, Ctx, ObjStream))
        llvm_unreachable("Target does not support MC emission.");
      PM.run(M);
    }

According to the SO here,

I guess, it is because your BasicBlock ends with invoke instruction, so it serves as BB's terminator. So when you remove it, your BB lose its terminator and that's an error, because every BasicBlock should end with terminator instruction.

Which is the case for my test case.

Some additional code has to be written to handle this case of the InvokeInst.

void VoidCallRemoval::mutate(llvm::Instruction *instruction) {
  assert(instruction);
  assert(canMutate(instruction));

  instruction->print(llvm::outs(), true);

  instruction->eraseFromParent();

  /// Handle special case of InvokeInst
}