C++ IRGenFunction::createAlloca方法代码示例

static void maybeEmitDebugInfoForLocalTypeData(IRGenFunction &IGF,
                                               LocalTypeDataKey key,
                                               llvm::Value *data) {
  // Only if debug info is enabled.
  if (!IGF.IGM.DebugInfo) return;

  // Only for type metadata.
  if (key.Kind != LocalTypeDataKind::forTypeMetadata()) return;

  // Only for archetypes, and not for opened archetypes.
  auto type = dyn_cast<ArchetypeType>(key.Type);
  if (!type) return;
  if (type->getOpenedExistentialType()) return;

  // At -O0, create an alloca to keep the type alive.
  auto name = type->getFullName();
  if (!IGF.IGM.IRGen.Opts.Optimize) {
    auto temp = IGF.createAlloca(data->getType(), IGF.IGM.getPointerAlignment(),
                                 name);
    IGF.Builder.CreateStore(data, temp);
    data = temp.getAddress();
  }

  // Emit debug info for the metadata.
  IGF.IGM.DebugInfo->emitTypeMetadata(IGF, data, name);
}

static void maybeEmitDebugInfoForLocalTypeData(IRGenFunction &IGF,
                                               LocalTypeDataKey key,
                                               MetadataResponse value) {
  // FIXME: This check doesn't entirely behave correctly for non-transparent
  // functions that were inlined into transparent functions. Correct would be to
  // check which instruction requests the type metadata and see whether its
  // inlined function is transparent.
  auto * DS = IGF.getDebugScope();
  if (DS && DS->getInlinedFunction() &&
      DS->getInlinedFunction()->isTransparent())
    return;
  
  // Only for formal type metadata.
  if (key.Kind != LocalTypeDataKind::forFormalTypeMetadata())
    return;

  // Only for archetypes, and not for opened archetypes.
  auto type = dyn_cast<ArchetypeType>(key.Type);
  if (!type)
    return;
  if (type->getOpenedExistentialType())
    return;

  llvm::Value *data = value.getMetadata();

  // At -O0, create an alloca to keep the type alive.
  auto name = type->getFullName();
  if (!IGF.IGM.IRGen.Opts.shouldOptimize()) {
    auto alloca =
        IGF.createAlloca(data->getType(), IGF.IGM.getPointerAlignment(), name);
    IGF.Builder.CreateStore(data, alloca);
    data = alloca.getAddress();
  }

  // Only if debug info is enabled.
  if (!IGF.IGM.DebugInfo)
    return;

  // Emit debug info for the metadata.
  llvm::SmallString<8> AssocType;
  auto *oocTy = type->mapTypeOutOfContext().getPointer();
  {
    llvm::raw_svector_ostream OS(AssocType);
    while (auto *dependentMemberType = dyn_cast<DependentMemberType>(oocTy)) {
      OS << '.' << dependentMemberType->getName();
      oocTy = dependentMemberType->getBase().getPointer();
    }
  }
  auto *typeParam = cast<GenericTypeParamType>(oocTy);
  IGF.IGM.DebugInfo->emitTypeMetadata(IGF, data, typeParam->getDepth(),
                                      typeParam->getIndex(), AssocType);
}

ContainedAddress FixedTypeInfo::allocateStack(IRGenFunction &IGF, SILType T,
                                              const Twine &name) const {
  // If the type is known to be empty, don't actually allocate anything.
  if (isKnownEmpty(ResilienceExpansion::Maximal)) {
    auto addr = getUndefAddress();
    return { addr, addr };
  }

  Address alloca =
    IGF.createAlloca(getStorageType(), getFixedAlignment(), name);
  IGF.Builder.CreateLifetimeStart(alloca, getFixedSize());
  
  return { alloca, alloca };
}

ContainedAddress FixedTypeInfo::allocateStack(IRGenFunction &IGF, SILType T,
                                              const Twine &name) const {
  // If the type is known to be empty, don't actually allocate anything.
  if (isKnownEmpty()) {
    auto addr = getUndefAddress();
    return { addr, addr };
  }

  Address alloca =
    IGF.createAlloca(getStorageType(), getFixedAlignment(), name);
  // TODO: lifetime intrinsics?

  return { alloca, alloca };
}

static void setMetadataRef(IRGenFunction &IGF,
                           ArchetypeType *archetype,
                           llvm::Value *metadata) {
  assert(metadata->getType() == IGF.IGM.TypeMetadataPtrTy);
  IGF.setUnscopedLocalTypeData(CanType(archetype),
                               LocalTypeData::forMetatype(),
                               metadata);

  // Create a shadow copy of the metadata in an alloca for the debug info.
  StringRef Name = metadata->getName();
  if (!IGF.IGM.Opts.Optimize) {
    auto Alloca = IGF.createAlloca(metadata->getType(),
                                   IGF.IGM.getPointerAlignment(), Name);
    IGF.Builder.CreateAlignedStore(metadata, Alloca.getAddress(),
                                   IGF.IGM.getPointerAlignment().getValue());
    metadata = Alloca.getAddress();
  }

  // Emit debug info for the metadata.
  if (IGF.IGM.DebugInfo)
    IGF.IGM.DebugInfo->emitTypeMetadata(IGF, metadata, Name);
}

void
irgen::emitTypeLayoutVerifier(IRGenFunction &IGF,
                              ArrayRef<CanType> formalTypes) {
  llvm::Type *verifierArgTys[] = {
    IGF.IGM.TypeMetadataPtrTy,
    IGF.IGM.Int8PtrTy,
    IGF.IGM.Int8PtrTy,
    IGF.IGM.SizeTy,
    IGF.IGM.Int8PtrTy,
  };
  auto verifierFnTy = llvm::FunctionType::get(IGF.IGM.VoidTy,
                                              verifierArgTys,
                                              /*var arg*/ false);
  auto verifierFn = IGF.IGM.Module.getOrInsertFunction(
                                       "_swift_debug_verifyTypeLayoutAttribute",
                                       verifierFnTy);
  struct VerifierArgumentBuffers {
    Address runtimeBuf, staticBuf;
  };
  llvm::DenseMap<llvm::Type *, VerifierArgumentBuffers>
    verifierArgBufs;
  
  auto getSizeConstant = [&](Size sz) -> llvm::Constant * {
    return llvm::ConstantInt::get(IGF.IGM.SizeTy, sz.getValue());
  };
  auto getAlignmentMaskConstant = [&](Alignment a) -> llvm::Constant * {
    return llvm::ConstantInt::get(IGF.IGM.SizeTy, a.getValue() - 1);
  };
  auto getBoolConstant = [&](bool b) -> llvm::Constant * {
    return llvm::ConstantInt::get(IGF.IGM.Int1Ty, b);
  };

  SmallString<20> numberBuf;

  for (auto formalType : formalTypes) {
    // Runtime type metadata always represents the maximal abstraction level of
    // the type.
    auto anyTy = ProtocolCompositionType::get(IGF.IGM.Context, {});
    auto openedAnyTy = ArchetypeType::getOpened(anyTy);
    auto maxAbstraction = AbstractionPattern(openedAnyTy);
    auto &ti = IGF.getTypeInfoForUnlowered(maxAbstraction, formalType);
    
    // If there's no fixed type info, we rely on the runtime anyway, so there's
    // nothing to verify.
    // TODO: There are some traits of partially-fixed layouts we could check too.
    auto *fixedTI = dyn_cast<FixedTypeInfo>(&ti);
    if (!fixedTI)
      return;
    
    auto metadata = IGF.emitTypeMetadataRef(formalType);
    
    auto verify = [&](llvm::Value *runtimeVal,
                      llvm::Value *staticVal,
                      const llvm::Twine &description) {
      assert(runtimeVal->getType() == staticVal->getType());
      // Get or create buffers for the arguments.
      VerifierArgumentBuffers bufs;
      auto foundBufs = verifierArgBufs.find(runtimeVal->getType());
      if (foundBufs != verifierArgBufs.end()) {
        bufs = foundBufs->second;
      } else {
        Address runtimeBuf = IGF.createAlloca(runtimeVal->getType(),
                                              IGF.IGM.getPointerAlignment(),
                                              "runtime");
        Address staticBuf = IGF.createAlloca(staticVal->getType(),
                                             IGF.IGM.getPointerAlignment(),
                                             "static");
        bufs = {runtimeBuf, staticBuf};
        verifierArgBufs[runtimeVal->getType()] = bufs;
      }
      
      IGF.Builder.CreateStore(runtimeVal, bufs.runtimeBuf);
      IGF.Builder.CreateStore(staticVal, bufs.staticBuf);
      
      auto runtimePtr = IGF.Builder.CreateBitCast(bufs.runtimeBuf.getAddress(),
                                                  IGF.IGM.Int8PtrTy);
      auto staticPtr = IGF.Builder.CreateBitCast(bufs.staticBuf.getAddress(),
                                                 IGF.IGM.Int8PtrTy);
      auto count = llvm::ConstantInt::get(IGF.IGM.SizeTy,
                    IGF.IGM.DataLayout.getTypeStoreSize(runtimeVal->getType()));
      auto msg
        = IGF.IGM.getAddrOfGlobalString(description.str());
      
      IGF.Builder.CreateCall(
          verifierFn, {metadata, runtimePtr, staticPtr, count, msg});
    };

    // Check that the fixed layout matches the runtime layout.
    SILType layoutType = SILType::getPrimitiveObjectType(formalType);
    verify(emitLoadOfSize(IGF, layoutType),
           getSizeConstant(fixedTI->getFixedSize()),
           "size");
    verify(emitLoadOfAlignmentMask(IGF, layoutType),
           getAlignmentMaskConstant(fixedTI->getFixedAlignment()),
           "alignment mask");
    verify(emitLoadOfStride(IGF, layoutType),
           getSizeConstant(fixedTI->getFixedStride()),
           "stride");
    verify(emitLoadOfIsInline(IGF, layoutType),
           getBoolConstant(fixedTI->getFixedPacking(IGF.IGM)
//.........这里部分代码省略.........

//.........这里部分代码省略.........
        objcObject = nullptr;
        break;
      }
      case MetatypeRepresentation::ObjC:
        // Metatype is already an ObjC object.
        objcObject = value;
        break;
      }
    } else {
      // Class instance is already an ObjC object.
      objcObject = value;
    }
    if (objcObject)
      objcObject = IGF.Builder.CreateBitCast(objcObject,
                                             IGF.IGM.UnknownRefCountedPtrTy);
    
    // Pick the cast function based on the cast mode and on whether we're
    // casting a Swift metatype or ObjC object.
    llvm::Value *castFn;
    switch (mode) {
    case CheckedCastMode::Unconditional:
      castFn = objcObject
        ? IGF.IGM.getDynamicCastObjCProtocolUnconditionalFn()
        : IGF.IGM.getDynamicCastTypeToObjCProtocolUnconditionalFn();
      break;
    case CheckedCastMode::Conditional:
      castFn = objcObject
        ? IGF.IGM.getDynamicCastObjCProtocolConditionalFn()
        : IGF.IGM.getDynamicCastTypeToObjCProtocolConditionalFn();
      break;
    }
    llvm::Value *objcCastObject = objcObject ? objcObject : value;
    
    Address protoRefsBuf = IGF.createAlloca(
                                        llvm::ArrayType::get(IGF.IGM.Int8PtrTy,
                                                             objcProtos.size()),
                                        IGF.IGM.getPointerAlignment(),
                                        "objc_protocols");
    protoRefsBuf = IGF.Builder.CreateBitCast(protoRefsBuf,
                                             IGF.IGM.Int8PtrPtrTy);

    for (unsigned index : indices(objcProtos)) {
      Address protoRefSlot = IGF.Builder.CreateConstArrayGEP(
                                                     protoRefsBuf, index,
                                                     IGF.IGM.getPointerSize());
      IGF.Builder.CreateStore(objcProtos[index], protoRefSlot);
      ++index;
    }

    
    objcCast = IGF.Builder.CreateCall(
        castFn,
        {objcCastObject, IGF.IGM.getSize(Size(objcProtos.size())),
         protoRefsBuf.getAddress()});
    resultValue = IGF.Builder.CreateBitCast(objcCast, resultType);
  }

  // If we don't need to look up any witness tables, we're done.
  if (witnessTableProtos.empty() && !checkClassConstraint) {
    ex.add(resultValue);
    return;
  }

  // If we're doing a conditional cast, and the ObjC protocol checks failed,
  // then the cast is done.
  Optional<ConditionalDominanceScope> condition;

//.........这里部分代码省略.........
        objcObject = nullptr;
        break;
      }
      case MetatypeRepresentation::ObjC:
        // Metatype is already an ObjC object.
        objcObject = value;
        break;
      }
    } else {
      // Class instance is already an ObjC object.
      objcObject = value;
    }
    if (objcObject)
      objcObject = IGF.Builder.CreateBitCast(objcObject,
                                             IGF.IGM.UnknownRefCountedPtrTy);
    
    // Pick the cast function based on the cast mode and on whether we're
    // casting a Swift metatype or ObjC object.
    llvm::Constant *castFn;
    switch (mode) {
    case CheckedCastMode::Unconditional:
      castFn = objcObject
        ? IGF.IGM.getDynamicCastObjCProtocolUnconditionalFn()
        : IGF.IGM.getDynamicCastTypeToObjCProtocolUnconditionalFn();
      break;
    case CheckedCastMode::Conditional:
      castFn = objcObject
        ? IGF.IGM.getDynamicCastObjCProtocolConditionalFn()
        : IGF.IGM.getDynamicCastTypeToObjCProtocolConditionalFn();
      break;
    }
    llvm::Value *objcCastObject = objcObject ? objcObject : value;
    
    Address protoRefsBuf = IGF.createAlloca(
                                        llvm::ArrayType::get(IGF.IGM.Int8PtrTy,
                                                             objcProtos.size()),
                                        IGF.IGM.getPointerAlignment(),
                                        "objc_protocols");
    protoRefsBuf = IGF.Builder.CreateBitCast(protoRefsBuf,
                                             IGF.IGM.Int8PtrPtrTy);

    for (unsigned index : indices(objcProtos)) {
      Address protoRefSlot = IGF.Builder.CreateConstArrayGEP(
                                                     protoRefsBuf, index,
                                                     IGF.IGM.getPointerSize());
      IGF.Builder.CreateStore(objcProtos[index], protoRefSlot);
      ++index;
    }

    
    auto cc = IGF.IGM.DefaultCC;
    if (auto fun = dyn_cast<llvm::Function>(castFn))
      cc = fun->getCallingConv();


    auto call = IGF.Builder.CreateCall(
        castFn,
        {objcCastObject, IGF.IGM.getSize(Size(objcProtos.size())),
         protoRefsBuf.getAddress()});
    call->setCallingConv(cc);
    objcCast = call;
    resultValue = IGF.Builder.CreateBitCast(objcCast, resultType);
  }

  // If we don't need to look up any witness tables, we're done.
  if (witnessTableProtos.empty() && !checkClassConstraint) {