C++ MemCpyInst::getDestAlignment方法代码示例

//.........这里部分代码省略.........

        if (isa<ConstantPointerNull>(CI->getOperand(0)))
          CI->setOperand(0, ConstantPointerNull::get(NewTy));

        if (isa<ConstantPointerNull>(CI->getOperand(1)))
          CI->setOperand(1, ConstantPointerNull::get(NewTy));

        continue;
      }

      // The operand's value should be corrected on its own and we don't want to
      // touch the users.
      if (isa<AddrSpaceCastInst>(V))
        continue;

      Type *EltTy = V->getType()->getPointerElementType();
      PointerType *NewTy = PointerType::get(EltTy, AS.LOCAL_ADDRESS);

      // FIXME: It doesn't really make sense to try to do this for all
      // instructions.
      V->mutateType(NewTy);

      // Adjust the types of any constant operands.
      if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
        if (isa<ConstantPointerNull>(SI->getOperand(1)))
          SI->setOperand(1, ConstantPointerNull::get(NewTy));

        if (isa<ConstantPointerNull>(SI->getOperand(2)))
          SI->setOperand(2, ConstantPointerNull::get(NewTy));
      } else if (PHINode *Phi = dyn_cast<PHINode>(V)) {
        for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I) {
          if (isa<ConstantPointerNull>(Phi->getIncomingValue(I)))
            Phi->setIncomingValue(I, ConstantPointerNull::get(NewTy));
        }
      }

      continue;
    }

    IntrinsicInst *Intr = cast<IntrinsicInst>(Call);
    Builder.SetInsertPoint(Intr);
    switch (Intr->getIntrinsicID()) {
    case Intrinsic::lifetime_start:
    case Intrinsic::lifetime_end:
      // These intrinsics are for address space 0 only
      Intr->eraseFromParent();
      continue;
    case Intrinsic::memcpy: {
      MemCpyInst *MemCpy = cast<MemCpyInst>(Intr);
      Builder.CreateMemCpy(MemCpy->getRawDest(), MemCpy->getDestAlignment(),
                           MemCpy->getRawSource(), MemCpy->getSourceAlignment(),
                           MemCpy->getLength(), MemCpy->isVolatile());
      Intr->eraseFromParent();
      continue;
    }
    case Intrinsic::memmove: {
      MemMoveInst *MemMove = cast<MemMoveInst>(Intr);
      Builder.CreateMemMove(MemMove->getRawDest(), MemMove->getDestAlignment(),
                            MemMove->getRawSource(), MemMove->getSourceAlignment(),
                            MemMove->getLength(), MemMove->isVolatile());
      Intr->eraseFromParent();
      continue;
    }
    case Intrinsic::memset: {
      MemSetInst *MemSet = cast<MemSetInst>(Intr);
      Builder.CreateMemSet(MemSet->getRawDest(), MemSet->getValue(),
                           MemSet->getLength(), MemSet->getDestAlignment(),
                           MemSet->isVolatile());
      Intr->eraseFromParent();
      continue;
    }
    case Intrinsic::invariant_start:
    case Intrinsic::invariant_end:
    case Intrinsic::invariant_group_barrier:
      Intr->eraseFromParent();
      // FIXME: I think the invariant marker should still theoretically apply,
      // but the intrinsics need to be changed to accept pointers with any
      // address space.
      continue;
    case Intrinsic::objectsize: {
      Value *Src = Intr->getOperand(0);
      Type *SrcTy = Src->getType()->getPointerElementType();
      Function *ObjectSize = Intrinsic::getDeclaration(Mod,
        Intrinsic::objectsize,
        { Intr->getType(), PointerType::get(SrcTy, AS.LOCAL_ADDRESS) }
      );

      CallInst *NewCall = Builder.CreateCall(
          ObjectSize, {Src, Intr->getOperand(1), Intr->getOperand(2)});
      Intr->replaceAllUsesWith(NewCall);
      Intr->eraseFromParent();
      continue;
    }
    default:
      Intr->print(errs());
      llvm_unreachable("Don't know how to promote alloca intrinsic use.");
    }
  }
  return true;
}

//.........这里部分代码省略.........
                               DL->getABITypeAlignment(Ty), Ty,
                               MemRef::Read | MemRef::Write);
        }
      }
    }
  }

  if (CS.isCall()) {
    const CallInst *CI = cast<CallInst>(CS.getInstruction());
    if (CI->isTailCall()) {
      const AttributeList &PAL = CI->getAttributes();
      unsigned ArgNo = 0;
      for (Value *Arg : CS.args()) {
        // Skip ByVal arguments since they will be memcpy'd to the callee's
        // stack anyway.
        if (PAL.hasParamAttribute(ArgNo++, Attribute::ByVal))
          continue;
        Value *Obj = findValue(Arg, /*OffsetOk=*/true);
        Assert(!isa<AllocaInst>(Obj),
               "Undefined behavior: Call with \"tail\" keyword references "
               "alloca",
               &I);
      }
    }
  }


  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I))
    switch (II->getIntrinsicID()) {
    default: break;

    // TODO: Check more intrinsics

    case Intrinsic::memcpy: {
      MemCpyInst *MCI = cast<MemCpyInst>(&I);
      // TODO: If the size is known, use it.
      visitMemoryReference(I, MCI->getDest(), MemoryLocation::UnknownSize,
                           MCI->getDestAlignment(), nullptr, MemRef::Write);
      visitMemoryReference(I, MCI->getSource(), MemoryLocation::UnknownSize,
                           MCI->getSourceAlignment(), nullptr, MemRef::Read);

      // Check that the memcpy arguments don't overlap. The AliasAnalysis API
      // isn't expressive enough for what we really want to do. Known partial
      // overlap is not distinguished from the case where nothing is known.
      uint64_t Size = 0;
      if (const ConstantInt *Len =
              dyn_cast<ConstantInt>(findValue(MCI->getLength(),
                                              /*OffsetOk=*/false)))
        if (Len->getValue().isIntN(32))
          Size = Len->getValue().getZExtValue();
      Assert(AA->alias(MCI->getSource(), Size, MCI->getDest(), Size) !=
                 MustAlias,
             "Undefined behavior: memcpy source and destination overlap", &I);
      break;
    }
    case Intrinsic::memmove: {
      MemMoveInst *MMI = cast<MemMoveInst>(&I);
      // TODO: If the size is known, use it.
      visitMemoryReference(I, MMI->getDest(), MemoryLocation::UnknownSize,
                           MMI->getDestAlignment(), nullptr, MemRef::Write);
      visitMemoryReference(I, MMI->getSource(), MemoryLocation::UnknownSize,
                           MMI->getSourceAlignment(), nullptr, MemRef::Read);
      break;
    }
    case Intrinsic::memset: {
      MemSetInst *MSI = cast<MemSetInst>(&I);
      // TODO: If the size is known, use it.
      visitMemoryReference(I, MSI->getDest(), MemoryLocation::UnknownSize,
                           MSI->getDestAlignment(), nullptr, MemRef::Write);
      break;
    }

    case Intrinsic::vastart:
      Assert(I.getParent()->getParent()->isVarArg(),
             "Undefined behavior: va_start called in a non-varargs function",
             &I);

      visitMemoryReference(I, CS.getArgument(0), MemoryLocation::UnknownSize, 0,
                           nullptr, MemRef::Read | MemRef::Write);
      break;
    case Intrinsic::vacopy:
      visitMemoryReference(I, CS.getArgument(0), MemoryLocation::UnknownSize, 0,
                           nullptr, MemRef::Write);
      visitMemoryReference(I, CS.getArgument(1), MemoryLocation::UnknownSize, 0,
                           nullptr, MemRef::Read);
      break;
    case Intrinsic::vaend:
      visitMemoryReference(I, CS.getArgument(0), MemoryLocation::UnknownSize, 0,
                           nullptr, MemRef::Read | MemRef::Write);
      break;

    case Intrinsic::stackrestore:
      // Stackrestore doesn't read or write memory, but it sets the
      // stack pointer, which the compiler may read from or write to
      // at any time, so check it for both readability and writeability.
      visitMemoryReference(I, CS.getArgument(0), MemoryLocation::UnknownSize, 0,
                           nullptr, MemRef::Read | MemRef::Write);
      break;
    }
}