[TI removal] Leverage the fact that TerminatorInst is gone to create a normal base class that provides all common "call" functionality.

[chandlerc]

Summary

This merges two complex CRTP mixins for the common "call" logic and
common operand bundle logic into a single, normal base class of
CallInst and InvokeInst. Going forward, users can typically
dyn_cast<CallBase> and use the resulting API. No more need for the
CallSite wrapper. I'm planning to migrate current usage of the wrapper
to directly use the base class and then it can be removed, but those are
simpler and much more incremental steps. The big change is to introduce
this abstraction into the type system.

I've tried to do some basic simplifications of the APIs that I couldn't
really help but touch as part of this:

• I've tried to organize the attribute API and bundle API into groups to make understanding the API of CallBase easier. Without this, I wasn't able to navigate the API sanely for all of the ways I needed to modify it.
• I've added what seem like more clear and consistent APIs for getting at the called operand. These ended up being especially useful to consolidate the *numerous* duplicated code paths trying to do this.
• I've largely reworked the organization and implementation of the APIs for computing the argument operands as they needed to change to work with the new subclass approach.

To minimize any cost associated with this abstraction, I've moved the
operand layout in memory to store the called operand last. This makes
its position relative to the end of the operand array the same,
regardless of the subclass. It should make it much cheaper to reference
from the CallBase abstraction, and this is likely one of the most
frequent things to query.

We do still pay one abstraction penalty here: we have to branch to
determine whether there are 0 or 2 extra operands when computing the end
of the argument operand sequence. However, that seems both rare and
should optimize well. I've implemented this in a way specifically
designed to allow it to optimize fairly well. If this shows up in
profiles, we can add overrides of the relevant methods to the subclasses
that bypass this penalty. It seems very unlikely that this will be an
issue as the code was *already* dealing with an ever present abstraction
of whether or not there are operand bundles, so this isn't the first
branch to go into the computation.

I've tried to remove as much of the obvious vestigial API surface of the
old CRTP implementation as I could, but I suspect there is further
cleanup that should now be possible, especially around the operand
bundle APIs. I'm leaving all of that for future work in this patch as
enough things are changing here as-is.

One thing that made this harder for me to reason about and debug was the
pervasive use of unsigned values in subtraction and other arithmetic
computations. I had to debug more than one unintentional wrap. I've
switched a few of these to use int which seems substantially simpler,
but I've held back from doing this more broadly to avoid creating
confusing divergence within a single class's API.

I also worked to remove all of the magic numbers used to index into
operands, putting them behind named constants or putting them into
a single method with a comment and strictly using the method elsewhere.
This was necessary to be able to re-layout the operands as discussed
above.

[bkramer]

I like it.

llvm/include/llvm/IR/CallSite.h

for (arg_iterator AI = this->arg_begin(), E = this->arg_end(); AI != E;
          ++AI)
       if (AI->get() == Arg)
         return true;
     return false;
   }
 
 private:
   IterTy getCallee() const {
-    if (isCall()) // Skip Callee
-      return cast<CallInst>(getInstruction())->op_end() - 1;
-    else // Skip BB, BB, Callee
-      return cast<InvokeInst>(getInstruction())->op_end() - 3;
+    return cast<CallBase>(getInstruction())->op_end() - 1;
   }
 };
 
 class CallSite : public CallSiteBase<Function, BasicBlock, Value, User, Use,
                                      Instruction, CallInst, InvokeInst,
                                      User::op_iterator> {
 public:
   CallSite() = default;

llvm/include/llvm/IR/InstrTypes.h

 #include "llvm/ADT/None.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/IR/Attributes.h"
+#include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/OperandTraits.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/User.h"
 #include "llvm/IR/Value.h"

 
 // FIXME: these are redundant if CmpInst < BinaryOperator
 template <>
 struct OperandTraits<CmpInst> : public FixedNumOperandTraits<CmpInst, 2> {
 };
 
 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(CmpInst, Value)
 
-//===----------------------------------------------------------------------===//
-//                           FuncletPadInst Class
-//===----------------------------------------------------------------------===//
-class FuncletPadInst : public Instruction {
-private:
-  FuncletPadInst(const FuncletPadInst &CPI);
-
-  explicit FuncletPadInst(Instruction::FuncletPadOps Op, Value *ParentPad,
-                          ArrayRef<Value *> Args, unsigned Values,
-                          const Twine &NameStr, Instruction *InsertBefore);
-  explicit FuncletPadInst(Instruction::FuncletPadOps Op, Value *ParentPad,
-                          ArrayRef<Value *> Args, unsigned Values,
-                          const Twine &NameStr, BasicBlock *InsertAtEnd);
-
-  void init(Value *ParentPad, ArrayRef<Value *> Args, const Twine &NameStr);
-
-protected:
-  // Note: Instruction needs to be a friend here to call cloneImpl.
-  friend class Instruction;
-  friend class CatchPadInst;
-  friend class CleanupPadInst;
-
-  FuncletPadInst *cloneImpl() const;
-
-public:
-  /// Provide fast operand accessors
-  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
-
-  /// getNumArgOperands - Return the number of funcletpad arguments.
-  ///
-  unsigned getNumArgOperands() const { return getNumOperands() - 1; }
-
-  /// Convenience accessors
-
-  /// Return the outer EH-pad this funclet is nested within.
-  ///
-  /// Note: This returns the associated CatchSwitchInst if this FuncletPadInst
-  /// is a CatchPadInst.
-  Value *getParentPad() const { return Op<-1>(); }
-  void setParentPad(Value *ParentPad) {
-    assert(ParentPad);
-    Op<-1>() = ParentPad;
-  }
-
-  /// getArgOperand/setArgOperand - Return/set the i-th funcletpad argument.
-  ///
-  Value *getArgOperand(unsigned i) const { return getOperand(i); }
-  void setArgOperand(unsigned i, Value *v) { setOperand(i, v); }
-
-  /// arg_operands - iteration adapter for range-for loops.
-  op_range arg_operands() { return op_range(op_begin(), op_end() - 1); }
-
-  /// arg_operands - iteration adapter for range-for loops.
-  const_op_range arg_operands() const {
-    return const_op_range(op_begin(), op_end() - 1);
-  }
-
-  // Methods for support type inquiry through isa, cast, and dyn_cast:
-  static bool classof(const Instruction *I) { return I->isFuncletPad(); }
-  static bool classof(const Value *V) {
-    return isa<Instruction>(V) && classof(cast<Instruction>(V));
-  }
-};
-
-template <>
-struct OperandTraits<FuncletPadInst>
-    : public VariadicOperandTraits<FuncletPadInst, /*MINARITY=*/1> {};
-
-DEFINE_TRANSPARENT_OPERAND_ACCESSORS(FuncletPadInst, Value)
-
 /// A lightweight accessor for an operand bundle meant to be passed
 /// around by value.
 struct OperandBundleUse {
   ArrayRef<Use> Inputs;
 
   OperandBundleUse() = default;
   explicit OperandBundleUse(StringMapEntry<uint32_t> *Tag, ArrayRef<Use> Inputs)
       : Inputs(Inputs), Tag(Tag) {}
public:
   input_iterator input_end() const { return Inputs.end(); }
 
   StringRef getTag() const { return Tag; }
 };
 
 using OperandBundleDef = OperandBundleDefT<Value *>;
 using ConstOperandBundleDef = OperandBundleDefT<const Value *>;
 
-/// A mixin to add operand bundle functionality to llvm instruction
-/// classes.
-///
-/// OperandBundleUser uses the descriptor area co-allocated with the host User
-/// to store some meta information about which operands are "normal" operands,
-/// and which ones belong to some operand bundle.
+//===----------------------------------------------------------------------===//
+//                               CallBase Class
+//===----------------------------------------------------------------------===//
+
+/// Base class for all callable instructions (InvokeInst and CallInst)
+/// Holds everything related to calling a function.
 ///
-/// The layout of an operand bundle user is
+/// All call-like instructions are required to use a common operand layout:
+/// - Zero or more arguments to the call,
+/// - Zero or more operand bundles with zero or more operand inputs each
+///   bundle,
+/// - Zero or more subclass controlled operands
+/// - The called function.
+///
+/// This allows this base class to easily access the called function and the
+/// start of the arguments without knowing how many other operands a particular
+/// subclass requires. Note that accessing the end of the argument list isn't
+/// as cheap as most other operations on the base class.
+class CallBase : public Instruction {
+protected:
+  /// The last operand is the called operand.
+  static constexpr int CalledOperandOpEndIdx = -1;
+
+  AttributeList Attrs; ///< parameter attributes for callable
+  FunctionType *FTy;
+
+  template <class... ArgsTy>
+  CallBase(AttributeList const &A, FunctionType *FT, ArgsTy &&... Args)
+      : Instruction(std::forward<ArgsTy>(Args)...), Attrs(A), FTy(FT) {}
+
+  using Instruction::Instruction;
+
+  bool hasDescriptor() const { return Value::HasDescriptor; }
+
+  unsigned getNumSubclassExtraOperands() const {
+    switch (getOpcode()) {
+    case Instruction::Call:
+      return 0;
+    case Instruction::Invoke:
+      return 2;
+    }
+    llvm_unreachable("Invalid opcode!");
+  }
+
+public:
+  using Instruction::getContext;
+
+  static bool classof(const Instruction *I) {
+    return I->getOpcode() == Instruction::Call ||
+           I->getOpcode() == Instruction::Invoke;
+  }
+
+  FunctionType *getFunctionType() const { return FTy; }
+
+  void mutateFunctionType(FunctionType *FTy) {
+    Value::mutateType(FTy->getReturnType());
+    this->FTy = FTy;
+  }
+
+  /// Return the iterator pointing to the beginning of the argument list.
+  User::op_iterator arg_begin() { return op_begin(); }
+  User::const_op_iterator arg_begin() const {
+    return const_cast<CallBase *>(this)->arg_begin();
+  }
+
+  /// Return the iterator pointing to the end of the argument list.
+  User::op_iterator arg_end() {
+    // Walk from the end of the operands over the called operand, the subclass
+    // operands, and any operands for bundles to find the end of the argument
+    // operands.
+    return op_end() - getNumTotalBundleOperands() -
+           getNumSubclassExtraOperands() - 1;
+  }
+  User::const_op_iterator arg_end() const {
+    return const_cast<CallBase *>(this)->arg_end();
+  }
+
+  /// Iteration adapter for range-for loops.
+  iterator_range<User::op_iterator> arg_operands() {
+    return make_range(arg_begin(), arg_end());
+  }
+  iterator_range<User::const_op_iterator> arg_operands() const {
+    return make_range(arg_begin(), arg_end());
+  }
+
+  unsigned getNumArgOperands() const { return arg_end() - arg_begin(); }
+
+  Value *getArgOperand(unsigned i) const {
+    assert(i < getNumArgOperands() && "Out of bounds!");
+    return getOperand(i);
+  }
+
+  void setArgOperand(unsigned i, Value *v) {
+    assert(i < getNumArgOperands() && "Out of bounds!");
+    setOperand(i, v);
+  }
+
+  /// Wrappers for getting the \c Use of a call argument.
+  const Use &getArgOperandUse(unsigned i) const {
+    assert(i < getNumArgOperands() && "Out of bounds!");
+    return User::getOperandUse(i);
+  }
+  Use &getArgOperandUse(unsigned i) {
+    assert(i < getNumArgOperands() && "Out of bounds!");
+    return User::getOperandUse(i);
+  }
+
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+
+  Value *getCalledOperand() const { return Op<CalledOperandOpEndIdx>(); }
+
+  // DEPRECATED: This routine will be removed in favor of `getCalledOperand` in
+  // the near future.
+  Value *getCalledValue() const { return getCalledOperand(); }
+
+  const Use &getCalledOperandUse() const { return Op<CalledOperandOpEndIdx>(); }
+  Use &getCalledOperandUse() { return Op<CalledOperandOpEndIdx>(); }
+
+  /// Returns the function called, or null if this is an
+  /// indirect function invocation.
+  Function *getCalledFunction() const {
+    return dyn_cast_or_null<Function>(getCalledOperand());
+  }
+
+  void setCalledOperand(Value *V) { Op<CalledOperandOpEndIdx>() = V; }
+
+  /// Sets the function called, including updating the function type.
+  void setCalledFunction(Value *Fn) {
+    setCalledFunction(
+        cast<FunctionType>(cast<PointerType>(Fn->getType())->getElementType()),
+        Fn);
+  }
+
+  /// Sets the function called, including updating to the specified function
+  /// type.
+  void setCalledFunction(FunctionType *FTy, Value *Fn) {
+    this->FTy = FTy;
+    assert(FTy == cast<FunctionType>(
+                      cast<PointerType>(Fn->getType())->getElementType()));
+    setCalledOperand(Fn);
+  }
+
+  CallingConv::ID getCallingConv() const {
+    return static_cast<CallingConv::ID>(getSubclassDataFromInstruction() >> 2);
+  }
+
+  void setCallingConv(CallingConv::ID CC) {
+    auto ID = static_cast<unsigned>(CC);
+    assert(!(ID & ~CallingConv::MaxID) && "Unsupported calling convention");
+    setInstructionSubclassData((getSubclassDataFromInstruction() & 3) |
+                               (ID << 2));
+  }
+
+  /// \name Attribute API
   ///
-///          +-----------uint32_t End-------------------------------------+
-///          |                                                            |
-///          |  +--------uint32_t Begin--------------------+              |
-///          |  |                                          |              |
-///          ^  ^                                          v              v
-///  |------|------|----|----|----|----|----|---------|----|---------|----|-----
-///  | BOI0 | BOI1 | .. | DU | U0 | U1 | .. | BOI0_U0 | .. | BOI1_U0 | .. | Un
-///  |------|------|----|----|----|----|----|---------|----|---------|----|-----
-///   v  v                                  ^              ^
-///   |  |                                  |              |
-///   |  +--------uint32_t Begin------------+              |
-///   |                                                    |
-///   +-----------uint32_t End-----------------------------+
+  /// These methods access and modify attributes on this call (including
+  /// looking through to the attributes on the called function when necessary).
+  ///@{
+
+  /// Return the parameter attributes for this call.
   ///
+  AttributeList getAttributes() const { return Attrs; }
+
+  /// Set the parameter attributes for this call.
   ///
-/// BOI0, BOI1 ... are descriptions of operand bundles in this User's use list.
-/// These descriptions are installed and managed by this class, and they're all
-/// instances of OperandBundleUser<T>::BundleOpInfo.
+  void setAttributes(AttributeList A) { Attrs = A; }
+
+  /// Determine whether this call has the given attribute.
+  bool hasFnAttr(Attribute::AttrKind Kind) const {
+    assert(Kind != Attribute::NoBuiltin &&
+           "Use CallBase::isNoBuiltin() to check for Attribute::NoBuiltin");
+    return hasFnAttrImpl(Kind);
+  }
+
+  /// Determine whether this call has the given attribute.
+  bool hasFnAttr(StringRef Kind) const { return hasFnAttrImpl(Kind); }
+
+  /// adds the attribute to the list of attributes.
+  void addAttribute(unsigned i, Attribute::AttrKind Kind) {
+    AttributeList PAL = getAttributes();
+    PAL = PAL.addAttribute(getContext(), i, Kind);
+    setAttributes(PAL);
+  }
+
+  /// adds the attribute to the list of attributes.
+  void addAttribute(unsigned i, Attribute Attr) {
+    AttributeList PAL = getAttributes();
+    PAL = PAL.addAttribute(getContext(), i, Attr);
+    setAttributes(PAL);
+  }
+
+  /// Adds the attribute to the indicated argument
+  void addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+    assert(ArgNo < getNumArgOperands() && "Out of bounds");
+    AttributeList PAL = getAttributes();
+    PAL = PAL.addParamAttribute(getContext(), ArgNo, Kind);
+    setAttributes(PAL);
+  }
+
+  /// Adds the attribute to the indicated argument
+  void addParamAttr(unsigned ArgNo, Attribute Attr) {
+    assert(ArgNo < getNumArgOperands() && "Out of bounds");
+    AttributeList PAL = getAttributes();
+    PAL = PAL.addParamAttribute(getContext(), ArgNo, Attr);
+    setAttributes(PAL);
+  }
+
+  /// removes the attribute from the list of attributes.
+  void removeAttribute(unsigned i, Attribute::AttrKind Kind) {
+    AttributeList PAL = getAttributes();
+    PAL = PAL.removeAttribute(getContext(), i, Kind);
+    setAttributes(PAL);
+  }
+
+  /// removes the attribute from the list of attributes.
+  void removeAttribute(unsigned i, StringRef Kind) {
+    AttributeList PAL = getAttributes();
+    PAL = PAL.removeAttribute(getContext(), i, Kind);
+    setAttributes(PAL);
+  }
+
+  /// Removes the attribute from the given argument
+  void removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+    assert(ArgNo < getNumArgOperands() && "Out of bounds");
+    AttributeList PAL = getAttributes();
+    PAL = PAL.removeParamAttribute(getContext(), ArgNo, Kind);
+    setAttributes(PAL);
+  }
+
+  /// Removes the attribute from the given argument
+  void removeParamAttr(unsigned ArgNo, StringRef Kind) {
+    assert(ArgNo < getNumArgOperands() && "Out of bounds");
+    AttributeList PAL = getAttributes();
+    PAL = PAL.removeParamAttribute(getContext(), ArgNo, Kind);
+    setAttributes(PAL);
+  }
+
+  /// adds the dereferenceable attribute to the list of attributes.
+  void addDereferenceableAttr(unsigned i, uint64_t Bytes) {
+    AttributeList PAL = getAttributes();
+    PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
+    setAttributes(PAL);
+  }
+
+  /// adds the dereferenceable_or_null attribute to the list of
+  /// attributes.
+  void addDereferenceableOrNullAttr(unsigned i, uint64_t Bytes) {
+    AttributeList PAL = getAttributes();
+    PAL = PAL.addDereferenceableOrNullAttr(getContext(), i, Bytes);
+    setAttributes(PAL);
+  }
+
+  /// Determine whether the return value has the given attribute.
+  bool hasRetAttr(Attribute::AttrKind Kind) const;
+
+  /// Determine whether the argument or parameter has the given attribute.
+  bool paramHasAttr(unsigned ArgNo, Attribute::AttrKind Kind) const;
+
+  /// Get the attribute of a given kind at a position.
+  Attribute getAttribute(unsigned i, Attribute::AttrKind Kind) const {
+    return getAttributes().getAttribute(i, Kind);
+  }
+
+  /// Get the attribute of a given kind at a position.
+  Attribute getAttribute(unsigned i, StringRef Kind) const {
+    return getAttributes().getAttribute(i, Kind);
+  }
+
+  /// Get the attribute of a given kind from a given arg
+  Attribute getParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) const {
+    assert(ArgNo < getNumArgOperands() && "Out of bounds");
+    return getAttributes().getParamAttr(ArgNo, Kind);
+  }
+
+  /// Get the attribute of a given kind from a given arg
+  Attribute getParamAttr(unsigned ArgNo, StringRef Kind) const {
+    assert(ArgNo < getNumArgOperands() && "Out of bounds");
+    return getAttributes().getParamAttr(ArgNo, Kind);
+  }
+
+  /// Return true if the data operand at index \p i has the attribute \p
+  /// A.
   ///
-/// DU is an additional descriptor installed by User's 'operator new' to keep
-/// track of the 'BOI0 ... BOIN' co-allocation.  OperandBundleUser does not
-/// access or modify DU in any way, it's an implementation detail private to
-/// User.
+  /// Data operands include call arguments and values used in operand bundles,
+  /// but does not include the callee operand.  This routine dispatches to the
+  /// underlying AttributeList or the OperandBundleUser as appropriate.
   ///
-/// The regular Use& vector for the User starts at U0.  The operand bundle uses
-/// are part of the Use& vector, just like normal uses.  In the diagram above,
-/// the operand bundle uses start at BOI0_U0.  Each instance of BundleOpInfo has
-/// information about a contiguous set of uses constituting an operand bundle,
-/// and the total set of operand bundle uses themselves form a contiguous set of
-/// uses (i.e. there are no gaps between uses corresponding to individual
-/// operand bundles).
+  /// The index \p i is interpreted as
   ///
-/// This class does not know the location of the set of operand bundle uses
-/// within the use list -- that is decided by the User using this class via the
-/// BeginIdx argument in populateBundleOperandInfos.
+  ///  \p i == Attribute::ReturnIndex  -> the return value
+  ///  \p i in [1, arg_size + 1)  -> argument number (\p i - 1)
+  ///  \p i in [arg_size + 1, data_operand_size + 1) -> bundle operand at index
+  ///     (\p i - 1) in the operand list.
+  bool dataOperandHasImpliedAttr(unsigned i, Attribute::AttrKind Kind) const {
+    // Note that we have to add one because `i` isn't zero-indexed.
+    assert(i < (getNumArgOperands() + getNumTotalBundleOperands() + 1) &&
+           "Data operand index out of bounds!");
+
+    // The attribute A can either be directly specified, if the operand in
+    // question is a call argument; or be indirectly implied by the kind of its
+    // containing operand bundle, if the operand is a bundle operand.
+
+    if (i == AttributeList::ReturnIndex)
+      return hasRetAttr(Kind);
+
+    // FIXME: Avoid these i - 1 calculations and update the API to use
+    // zero-based indices.
+    if (i < (getNumArgOperands() + 1))
+      return paramHasAttr(i - 1, Kind);
+
+    assert(hasOperandBundles() && i >= (getBundleOperandsStartIndex() + 1) &&
+           "Must be either a call argument or an operand bundle!");
+    return bundleOperandHasAttr(i - 1, Kind);
+  }
+
+  /// Extract the alignment of the return value.
+  unsigned getRetAlignment() const { return Attrs.getRetAlignment(); }
+
+  /// Extract the alignment for a call or parameter (0=unknown).
+  unsigned getParamAlignment(unsigned ArgNo) const {
+    return Attrs.getParamAlignment(ArgNo);
+  }
+
+  /// Extract the number of dereferenceable bytes for a call or
+  /// parameter (0=unknown).
+  uint64_t getDereferenceableBytes(unsigned i) const {
+    return Attrs.getDereferenceableBytes(i);
+  }
+
+  /// Extract the number of dereferenceable_or_null bytes for a call or
+  /// parameter (0=unknown).
+  uint64_t getDereferenceableOrNullBytes(unsigned i) const {
+    return Attrs.getDereferenceableOrNullBytes(i);
+  }
+
+  /// Determine if the return value is marked with NoAlias attribute.
+  bool returnDoesNotAlias() const {
+    return Attrs.hasAttribute(AttributeList::ReturnIndex, Attribute::NoAlias);
+  }
+
+  /// If one of the arguments has the 'returned' attribute, returns its
+  /// operand value. Otherwise, return nullptr.
+  Value *getReturnedArgOperand() const;
+
+  /// Return true if the call should not be treated as a call to a
+  /// builtin.
+  bool isNoBuiltin() const {
+    return hasFnAttrImpl(Attribute::NoBuiltin) &&
+           !hasFnAttrImpl(Attribute::Builtin);
+  }
+
+  /// Determine if the call requires strict floating point semantics.
+  bool isStrictFP() const { return hasFnAttr(Attribute::StrictFP); }
+
+  /// Return true if the call should not be inlined.
+  bool isNoInline() const { return hasFnAttr(Attribute::NoInline); }
+  void setIsNoInline() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::NoInline);
+  }
+  /// Determine if the call does not access memory.
+  bool doesNotAccessMemory() const { return hasFnAttr(Attribute::ReadNone); }
+  void setDoesNotAccessMemory() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::ReadNone);
+  }
+
+  /// Determine if the call does not access or only reads memory.
+  bool onlyReadsMemory() const {
+    return doesNotAccessMemory() || hasFnAttr(Attribute::ReadOnly);
+  }
+  void setOnlyReadsMemory() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::ReadOnly);
+  }
+
+  /// Determine if the call does not access or only writes memory.
+  bool doesNotReadMemory() const {
+    return doesNotAccessMemory() || hasFnAttr(Attribute::WriteOnly);
+  }
+  void setDoesNotReadMemory() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::WriteOnly);
+  }
+
+  /// Determine if the call can access memmory only using pointers based
+  /// on its arguments.
+  bool onlyAccessesArgMemory() const {
+    return hasFnAttr(Attribute::ArgMemOnly);
+  }
+  void setOnlyAccessesArgMemory() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::ArgMemOnly);
+  }
+
+  /// Determine if the function may only access memory that is
+  /// inaccessible from the IR.
+  bool onlyAccessesInaccessibleMemory() const {
+    return hasFnAttr(Attribute::InaccessibleMemOnly);
+  }
+  void setOnlyAccessesInaccessibleMemory() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::InaccessibleMemOnly);
+  }
+
+  /// Determine if the function may only access memory that is
+  /// either inaccessible from the IR or pointed to by its arguments.
+  bool onlyAccessesInaccessibleMemOrArgMem() const {
+    return hasFnAttr(Attribute::InaccessibleMemOrArgMemOnly);
+  }
+  void setOnlyAccessesInaccessibleMemOrArgMem() {
+    addAttribute(AttributeList::FunctionIndex,
+                 Attribute::InaccessibleMemOrArgMemOnly);
+  }
+  /// Determine if the call cannot return.
+  bool doesNotReturn() const { return hasFnAttr(Attribute::NoReturn); }
+  void setDoesNotReturn() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::NoReturn);
+  }
+
+  /// Determine if the call should not perform indirect branch tracking.
+  bool doesNoCfCheck() const { return hasFnAttr(Attribute::NoCfCheck); }
+
+  /// Determine if the call cannot unwind.
+  bool doesNotThrow() const { return hasFnAttr(Attribute::NoUnwind); }
+  void setDoesNotThrow() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
+  }
+
+  /// Determine if the invoke cannot be duplicated.
+  bool cannotDuplicate() const { return hasFnAttr(Attribute::NoDuplicate); }
+  void setCannotDuplicate() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::NoDuplicate);
+  }
+
+  /// Determine if the invoke is convergent
+  bool isConvergent() const { return hasFnAttr(Attribute::Convergent); }
+  void setConvergent() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::Convergent);
+  }
+  void setNotConvergent() {
+    removeAttribute(AttributeList::FunctionIndex, Attribute::Convergent);
+  }
+
+  /// Determine if the call returns a structure through first
+  /// pointer argument.
+  bool hasStructRetAttr() const {
+    if (getNumArgOperands() == 0)
+      return false;
+
+    // Be friendly and also check the callee.
+    return paramHasAttr(0, Attribute::StructRet);
+  }
+
+  /// Determine if any call argument is an aggregate passed by value.
+  bool hasByValArgument() const {
+    return Attrs.hasAttrSomewhere(Attribute::ByVal);
+  }
+
+  ///@{
+  // End of attribute API.
+
+  /// \name Operand Bundle API
   ///
-/// Currently operand bundle users with hung-off operands are not supported.
-template <typename InstrTy, typename OpIteratorTy> class OperandBundleUser {
-public:
+  /// This group of methods provides the API to access and manipulate operand
+  /// bundles on this call.
+  /// @{
+
   /// Return the number of operand bundles associated with this User.
   unsigned getNumOperandBundles() const {
     return std::distance(bundle_op_info_begin(), bundle_op_info_end());
   }
 
   /// Return true if this User has any operand bundles.
   bool hasOperandBundles() const { return getNumOperandBundles() != 0; }
 
bool bundleOperandHasAttr(unsigned OpIdx,  Attribute::AttrKind A) const {
     auto &BOI = getBundleOpInfoForOperand(OpIdx);
     auto OBU = operandBundleFromBundleOpInfo(BOI);
     return OBU.operandHasAttr(OpIdx - BOI.Begin, A);
   }
 
   /// Return true if \p Other has the same sequence of operand bundle
   /// tags with the same number of operands on each one of them as this
   /// OperandBundleUser.
-  bool hasIdenticalOperandBundleSchema(
-      const OperandBundleUser<InstrTy, OpIteratorTy> &Other) const {
+  bool hasIdenticalOperandBundleSchema(const CallBase &Other) const {
     if (getNumOperandBundles() != Other.getNumOperandBundles())
       return false;
 
     return std::equal(bundle_op_info_begin(), bundle_op_info_end(),
                       Other.bundle_op_info_begin());
   }
 
   /// Return true if this operand bundle user contains operand bundles
   /// with tags other than those specified in \p IDs.
   bool hasOperandBundlesOtherThan(ArrayRef<uint32_t> IDs) const {
     for (unsigned i = 0, e = getNumOperandBundles(); i != e; ++i) {
       uint32_t ID = getOperandBundleAt(i).getTagID();
       if (!is_contained(IDs, ID))
         return true;
     }
     return false;
   }
 
-protected:
   /// Is the function attribute S disallowed by some operand bundle on
   /// this operand bundle user?
   bool isFnAttrDisallowedByOpBundle(StringRef S) const {
     // Operand bundles only possibly disallow readnone, readonly and argmenonly
     // attributes.  All String attributes are fine.
     return false;
   }
 
bool operator==(const BundleOpInfo &Other) const {
       return Tag == Other.Tag && Begin == Other.Begin && End == Other.End;
     }
   };
 
   /// Simple helper function to map a BundleOpInfo to an
   /// OperandBundleUse.
   OperandBundleUse
   operandBundleFromBundleOpInfo(const BundleOpInfo &BOI) const {
-    auto op_begin = static_cast<const InstrTy *>(this)->op_begin();
-    ArrayRef<Use> Inputs(op_begin + BOI.Begin, op_begin + BOI.End);
+    auto begin = op_begin();
+    ArrayRef<Use> Inputs(begin + BOI.Begin, begin + BOI.End);
     return OperandBundleUse(BOI.Tag, Inputs);
   }
 
   using bundle_op_iterator = BundleOpInfo *;
   using const_bundle_op_iterator = const BundleOpInfo *;
 
   /// Return the start of the list of BundleOpInfo instances associated
   /// with this OperandBundleUser.
+  ///
+  /// OperandBundleUser uses the descriptor area co-allocated with the host User
+  /// to store some meta information about which operands are "normal" operands,
+  /// and which ones belong to some operand bundle.
+  ///
+  /// The layout of an operand bundle user is
+  ///
+  ///          +-----------uint32_t End-------------------------------------+
+  ///          |                                                            |
+  ///          |  +--------uint32_t Begin--------------------+              |
+  ///          |  |                                          |              |
+  ///          ^  ^                                          v              v
+  ///  |------|------|----|----|----|----|----|---------|----|---------|----|-----
+  ///  | BOI0 | BOI1 | .. | DU | U0 | U1 | .. | BOI0_U0 | .. | BOI1_U0 | .. | Un
+  ///  |------|------|----|----|----|----|----|---------|----|---------|----|-----
+  ///   v  v                                  ^              ^
+  ///   |  |                                  |              |
+  ///   |  +--------uint32_t Begin------------+              |
+  ///   |                                                    |
+  ///   +-----------uint32_t End-----------------------------+
+  ///
+  ///
+  /// BOI0, BOI1 ... are descriptions of operand bundles in this User's use
+  /// list. These descriptions are installed and managed by this class, and
+  /// they're all instances of OperandBundleUser<T>::BundleOpInfo.
+  ///
+  /// DU is an additional descriptor installed by User's 'operator new' to keep
+  /// track of the 'BOI0 ... BOIN' co-allocation.  OperandBundleUser does not
+  /// access or modify DU in any way, it's an implementation detail private to
+  /// User.
+  ///
+  /// The regular Use& vector for the User starts at U0.  The operand bundle
+  /// uses are part of the Use& vector, just like normal uses.  In the diagram
+  /// above, the operand bundle uses start at BOI0_U0.  Each instance of
+  /// BundleOpInfo has information about a contiguous set of uses constituting
+  /// an operand bundle, and the total set of operand bundle uses themselves
+  /// form a contiguous set of uses (i.e. there are no gaps between uses
+  /// corresponding to individual operand bundles).
+  ///
+  /// This class does not know the location of the set of operand bundle uses
+  /// within the use list -- that is decided by the User using this class via
+  /// the BeginIdx argument in populateBundleOperandInfos.
+  ///
+  /// Currently operand bundle users with hung-off operands are not supported.
   bundle_op_iterator bundle_op_info_begin() {
-    if (!static_cast<InstrTy *>(this)->hasDescriptor())
+    if (!hasDescriptor())
       return nullptr;
 
-    uint8_t *BytesBegin = static_cast<InstrTy *>(this)->getDescriptor().begin();
+    uint8_t *BytesBegin = getDescriptor().begin();
     return reinterpret_cast<bundle_op_iterator>(BytesBegin);
   }
 
   /// Return the start of the list of BundleOpInfo instances associated
   /// with this OperandBundleUser.
   const_bundle_op_iterator bundle_op_info_begin() const {
-    auto *NonConstThis =
-        const_cast<OperandBundleUser<InstrTy, OpIteratorTy> *>(this);
+    auto *NonConstThis = const_cast<CallBase *>(this);
     return NonConstThis->bundle_op_info_begin();
   }
 
   /// Return the end of the list of BundleOpInfo instances associated
   /// with this OperandBundleUser.
   bundle_op_iterator bundle_op_info_end() {
-    if (!static_cast<InstrTy *>(this)->hasDescriptor())
+    if (!hasDescriptor())
       return nullptr;
 
-    uint8_t *BytesEnd = static_cast<InstrTy *>(this)->getDescriptor().end();
+    uint8_t *BytesEnd = getDescriptor().end();
     return reinterpret_cast<bundle_op_iterator>(BytesEnd);
   }
 
   /// Return the end of the list of BundleOpInfo instances associated
   /// with this OperandBundleUser.
   const_bundle_op_iterator bundle_op_info_end() const {
-    auto *NonConstThis =
-        const_cast<OperandBundleUser<InstrTy, OpIteratorTy> *>(this);
+    auto *NonConstThis = const_cast<CallBase *>(this);
     return NonConstThis->bundle_op_info_end();
   }
 
   /// Return the range [\p bundle_op_info_begin, \p bundle_op_info_end).
   iterator_range<bundle_op_iterator> bundle_op_infos() {
     return make_range(bundle_op_info_begin(), bundle_op_info_end());
   }
 
   /// Return the range [\p bundle_op_info_begin, \p bundle_op_info_end).
   iterator_range<const_bundle_op_iterator> bundle_op_infos() const {
     return make_range(bundle_op_info_begin(), bundle_op_info_end());
   }
 
   /// Populate the BundleOpInfo instances and the Use& vector from \p
   /// Bundles.  Return the op_iterator pointing to the Use& one past the last
   /// last bundle operand use.
   ///
   /// Each \p OperandBundleDef instance is tracked by a OperandBundleInfo
   /// instance allocated in this User's descriptor.
-  OpIteratorTy populateBundleOperandInfos(ArrayRef<OperandBundleDef> Bundles,
-                                          const unsigned BeginIndex) {
-    auto It = static_cast<InstrTy *>(this)->op_begin() + BeginIndex;
-    for (auto &B : Bundles)
-      It = std::copy(B.input_begin(), B.input_end(), It);
-
-    auto *ContextImpl = static_cast<InstrTy *>(this)->getContext().pImpl;
-    auto BI = Bundles.begin();
-    unsigned CurrentIndex = BeginIndex;
-
-    for (auto &BOI : bundle_op_infos()) {
-      assert(BI != Bundles.end() && "Incorrect allocation?");
-
-      BOI.Tag = ContextImpl->getOrInsertBundleTag(BI->getTag());
-      BOI.Begin = CurrentIndex;
-      BOI.End = CurrentIndex + BI->input_size();
-      CurrentIndex = BOI.End;
-      BI++;
-    }
-
-    assert(BI == Bundles.end() && "Incorrect allocation?");
-
-    return It;
-  }
+  op_iterator populateBundleOperandInfos(ArrayRef<OperandBundleDef> Bundles,
+                                         const unsigned BeginIndex);
 
   /// Return the BundleOpInfo for the operand at index OpIdx.
   ///
   /// It is an error to call this with an OpIdx that does not correspond to an
   /// bundle operand.
   const BundleOpInfo &getBundleOpInfoForOperand(unsigned OpIdx) const {
     for (auto &BOI : bundle_op_infos())
       if (BOI.Begin <= OpIdx && OpIdx < BOI.End)
         return BOI;
 
     llvm_unreachable("Did not find operand bundle for operand!");
   }
 
+protected:
   /// Return the total number of values used in \p Bundles.
   static unsigned CountBundleInputs(ArrayRef<OperandBundleDef> Bundles) {
     unsigned Total = 0;
     for (auto &B : Bundles)
       Total += B.input_size();
     return Total;
   }
+
+  /// @}
+  // End of operand bundle API.
+
+private:
+  bool hasFnAttrOnCalledFunction(Attribute::AttrKind Kind) const;
+  bool hasFnAttrOnCalledFunction(StringRef Kind) const;
+
+  template <typename AttrKind> bool hasFnAttrImpl(AttrKind Kind) const {
+    if (Attrs.hasAttribute(AttributeList::FunctionIndex, Kind))
+      return true;
+
+    // Operand bundles override attributes on the called function, but don't
+    // override attributes directly present on the call instruction.
+    if (isFnAttrDisallowedByOpBundle(Kind))
+      return false;
+
+    return hasFnAttrOnCalledFunction(Kind);
+  }
+};
+
+template <>
+struct OperandTraits<CallBase> : public VariadicOperandTraits<CallBase, 1> {};
+
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(CallBase, Value)
+
+//===----------------------------------------------------------------------===//
+//                           FuncletPadInst Class
+//===----------------------------------------------------------------------===//
+class FuncletPadInst : public Instruction {
+private:
+  FuncletPadInst(const FuncletPadInst &CPI);
+
+  explicit FuncletPadInst(Instruction::FuncletPadOps Op, Value *ParentPad,
+                          ArrayRef<Value *> Args, unsigned Values,
+                          const Twine &NameStr, Instruction *InsertBefore);
+  explicit FuncletPadInst(Instruction::FuncletPadOps Op, Value *ParentPad,
+                          ArrayRef<Value *> Args, unsigned Values,
+                          const Twine &NameStr, BasicBlock *InsertAtEnd);
+
+  void init(Value *ParentPad, ArrayRef<Value *> Args, const Twine &NameStr);
+
+protected:
+  // Note: Instruction needs to be a friend here to call cloneImpl.
+  friend class Instruction;
+  friend class CatchPadInst;
+  friend class CleanupPadInst;
+
+  FuncletPadInst *cloneImpl() const;
+
+public:
+  /// Provide fast operand accessors
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+
+  /// getNumArgOperands - Return the number of funcletpad arguments.
+  ///
+  unsigned getNumArgOperands() const { return getNumOperands() - 1; }
+
+  /// Convenience accessors
+
+  /// Return the outer EH-pad this funclet is nested within.
+  ///
+  /// Note: This returns the associated CatchSwitchInst if this FuncletPadInst
+  /// is a CatchPadInst.
+  Value *getParentPad() const { return Op<-1>(); }
+  void setParentPad(Value *ParentPad) {
+    assert(ParentPad);
+    Op<-1>() = ParentPad;
+  }
+
+  /// getArgOperand/setArgOperand - Return/set the i-th funcletpad argument.
+  ///
+  Value *getArgOperand(unsigned i) const { return getOperand(i); }
+  void setArgOperand(unsigned i, Value *v) { setOperand(i, v); }
+
+  /// arg_operands - iteration adapter for range-for loops.
+  op_range arg_operands() { return op_range(op_begin(), op_end() - 1); }
+
+  /// arg_operands - iteration adapter for range-for loops.
+  const_op_range arg_operands() const {
+    return const_op_range(op_begin(), op_end() - 1);
+  }
+
+  // Methods for support type inquiry through isa, cast, and dyn_cast:
+  static bool classof(const Instruction *I) { return I->isFuncletPad(); }
+  static bool classof(const Value *V) {
+    return isa<Instruction>(V) && classof(cast<Instruction>(V));
+  }
 };
 
+template <>
+struct OperandTraits<FuncletPadInst>
+    : public VariadicOperandTraits<FuncletPadInst, /*MINARITY=*/1> {};
+
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(FuncletPadInst, Value)
+
 } // end namespace llvm
 
 #endif // LLVM_IR_INSTRTYPES_H

llvm/include/llvm/IR/Instructions.h

public:
   static bool classof(const Instruction *I) {
     return I->getOpcode() == Instruction::FCmp;
   }
   static bool classof(const Value *V) {
     return isa<Instruction>(V) && classof(cast<Instruction>(V));
   }
 };
 
-class CallInst;
-class InvokeInst;
-
-template <class T> struct CallBaseParent { using type = Instruction; };
-
-//===----------------------------------------------------------------------===//
-/// Base class for all callable instructions (InvokeInst and CallInst)
-/// Holds everything related to calling a function, abstracting from the base
-/// type @p BaseInstTy and the concrete instruction @p InstTy
-///
-template <class InstTy>
-class CallBase : public CallBaseParent<InstTy>::type,
-                 public OperandBundleUser<InstTy, User::op_iterator> {
-protected:
-  AttributeList Attrs; ///< parameter attributes for callable
-  FunctionType *FTy;
-  using BaseInstTy = typename CallBaseParent<InstTy>::type;
-
-  template <class... ArgsTy>
-  CallBase(AttributeList const &A, FunctionType *FT, ArgsTy &&... Args)
-      : BaseInstTy(std::forward<ArgsTy>(Args)...), Attrs(A), FTy(FT) {}
-  bool hasDescriptor() const { return Value::HasDescriptor; }
-
-  using BaseInstTy::BaseInstTy;
-
-  using OperandBundleUser<InstTy,
-                          User::op_iterator>::isFnAttrDisallowedByOpBundle;
-  using OperandBundleUser<InstTy, User::op_iterator>::getNumTotalBundleOperands;
-  using OperandBundleUser<InstTy, User::op_iterator>::bundleOperandHasAttr;
-  using Instruction::getSubclassDataFromInstruction;
-  using Instruction::setInstructionSubclassData;
-
-public:
-  using Instruction::getContext;
-  using OperandBundleUser<InstTy, User::op_iterator>::hasOperandBundles;
-  using OperandBundleUser<InstTy,
-                          User::op_iterator>::getBundleOperandsStartIndex;
-
-  static bool classof(const Instruction *I) {
-    llvm_unreachable(
-        "CallBase is not meant to be used as part of the classof hierarchy");
-  }
-
-public:
-  /// Return the parameter attributes for this call.
-  ///
-  AttributeList getAttributes() const { return Attrs; }
-
-  /// Set the parameter attributes for this call.
-  ///
-  void setAttributes(AttributeList A) { Attrs = A; }
-
-  FunctionType *getFunctionType() const { return FTy; }
-
-  void mutateFunctionType(FunctionType *FTy) {
-    Value::mutateType(FTy->getReturnType());
-    this->FTy = FTy;
-  }
-
-  /// Return the number of call arguments.
-  ///
-  unsigned getNumArgOperands() const {
-    return getNumOperands() - getNumTotalBundleOperands() - InstTy::ArgOffset;
-  }
-
-  /// getArgOperand/setArgOperand - Return/set the i-th call argument.
-  ///
-  Value *getArgOperand(unsigned i) const {
-    assert(i < getNumArgOperands() && "Out of bounds!");
-    return getOperand(i);
-  }
-  void setArgOperand(unsigned i, Value *v) {
-    assert(i < getNumArgOperands() && "Out of bounds!");
-    setOperand(i, v);
-  }
-
-  /// Return the iterator pointing to the beginning of the argument list.
-  User::op_iterator arg_begin() { return op_begin(); }
-
-  /// Return the iterator pointing to the end of the argument list.
-  User::op_iterator arg_end() {
-    // [ call args ], [ operand bundles ], callee
-    return op_end() - getNumTotalBundleOperands() - InstTy::ArgOffset;
-  }
-
-  /// Iteration adapter for range-for loops.
-  iterator_range<User::op_iterator> arg_operands() {
-    return make_range(arg_begin(), arg_end());
-  }
-
-  /// Return the iterator pointing to the beginning of the argument list.
-  User::const_op_iterator arg_begin() const { return op_begin(); }
-
-  /// Return the iterator pointing to the end of the argument list.
-  User::const_op_iterator arg_end() const {
-    // [ call args ], [ operand bundles ], callee
-    return op_end() - getNumTotalBundleOperands() - InstTy::ArgOffset;
-  }
-
-  /// Iteration adapter for range-for loops.
-  iterator_range<User::const_op_iterator> arg_operands() const {
-    return make_range(arg_begin(), arg_end());
-  }
-
-  /// Wrappers for getting the \c Use of a call argument.
-  const Use &getArgOperandUse(unsigned i) const {
-    assert(i < getNumArgOperands() && "Out of bounds!");
-    return User::getOperandUse(i);
-  }
-  Use &getArgOperandUse(unsigned i) {
-    assert(i < getNumArgOperands() && "Out of bounds!");
-    return User::getOperandUse(i);
-  }
-
-  /// If one of the arguments has the 'returned' attribute, return its
-  /// operand value. Otherwise, return nullptr.
-  Value *getReturnedArgOperand() const {
-    unsigned Index;
-
-    if (Attrs.hasAttrSomewhere(Attribute::Returned, &Index) && Index)
-      return getArgOperand(Index - AttributeList::FirstArgIndex);
-    if (const Function *F = getCalledFunction())
-      if (F->getAttributes().hasAttrSomewhere(Attribute::Returned, &Index) &&
-          Index)
-        return getArgOperand(Index - AttributeList::FirstArgIndex);
-
-    return nullptr;
-  }
-
-  User::op_iterator op_begin() {
-    return OperandTraits<CallBase>::op_begin(this);
-  }
-
-  User::const_op_iterator op_begin() const {
-    return OperandTraits<CallBase>::op_begin(const_cast<CallBase *>(this));
-  }
-
-  User::op_iterator op_end() { return OperandTraits<CallBase>::op_end(this); }
-
-  User::const_op_iterator op_end() const {
-    return OperandTraits<CallBase>::op_end(const_cast<CallBase *>(this));
-  }
-
-  Value *getOperand(unsigned i_nocapture) const {
-    assert(i_nocapture < OperandTraits<CallBase>::operands(this) &&
-           "getOperand() out of range!");
-    return cast_or_null<Value>(OperandTraits<CallBase>::op_begin(
-                                   const_cast<CallBase *>(this))[i_nocapture]
-                                   .get());
-  }
-
-  void setOperand(unsigned i_nocapture, Value *Val_nocapture) {
-    assert(i_nocapture < OperandTraits<CallBase>::operands(this) &&
-           "setOperand() out of range!");
-    OperandTraits<CallBase>::op_begin(this)[i_nocapture] = Val_nocapture;
-  }
-
-  unsigned getNumOperands() const {
-    return OperandTraits<CallBase>::operands(this);
-  }
-  template <int Idx_nocapture> Use &Op() {
-    return User::OpFrom<Idx_nocapture>(this);
-  }
-  template <int Idx_nocapture> const Use &Op() const {
-    return User::OpFrom<Idx_nocapture>(this);
-  }
-
-  /// Return the function called, or null if this is an
-  /// indirect function invocation.
-  ///
-  Function *getCalledFunction() const {
-    return dyn_cast_or_null<Function>(Op<-InstTy::ArgOffset>());
-  }
-
-  /// Determine whether this call has the given attribute.
-  bool hasFnAttr(Attribute::AttrKind Kind) const {
-    assert(Kind != Attribute::NoBuiltin &&
-           "Use CallBase::isNoBuiltin() to check for Attribute::NoBuiltin");
-    return hasFnAttrImpl(Kind);
-  }
-
-  /// Determine whether this call has the given attribute.
-  bool hasFnAttr(StringRef Kind) const { return hasFnAttrImpl(Kind); }
-
-  /// getCallingConv/setCallingConv - Get or set the calling convention of this
-  /// function call.
-  CallingConv::ID getCallingConv() const {
-    return static_cast<CallingConv::ID>(getSubclassDataFromInstruction() >> 2);
-  }
-  void setCallingConv(CallingConv::ID CC) {
-    auto ID = static_cast<unsigned>(CC);
-    assert(!(ID & ~CallingConv::MaxID) && "Unsupported calling convention");
-    setInstructionSubclassData((getSubclassDataFromInstruction() & 3) |
-                               (ID << 2));
-  }
-
-
-  /// adds the attribute to the list of attributes.
-  void addAttribute(unsigned i, Attribute::AttrKind Kind) {
-    AttributeList PAL = getAttributes();
-    PAL = PAL.addAttribute(getContext(), i, Kind);
-    setAttributes(PAL);
-  }
-
-  /// adds the attribute to the list of attributes.
-  void addAttribute(unsigned i, Attribute Attr) {
-    AttributeList PAL = getAttributes();
-    PAL = PAL.addAttribute(getContext(), i, Attr);
-    setAttributes(PAL);
-  }
-
-  /// Adds the attribute to the indicated argument
-  void addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
-    assert(ArgNo < getNumArgOperands() && "Out of bounds");
-    AttributeList PAL = getAttributes();
-    PAL = PAL.addParamAttribute(getContext(), ArgNo, Kind);
-    setAttributes(PAL);
-  }
-
-  /// Adds the attribute to the indicated argument
-  void addParamAttr(unsigned ArgNo, Attribute Attr) {
-    assert(ArgNo < getNumArgOperands() && "Out of bounds");
-    AttributeList PAL = getAttributes();
-    PAL = PAL.addParamAttribute(getContext(), ArgNo, Attr);
-    setAttributes(PAL);
-  }
-
-  /// removes the attribute from the list of attributes.
-  void removeAttribute(unsigned i, Attribute::AttrKind Kind) {
-    AttributeList PAL = getAttributes();
-    PAL = PAL.removeAttribute(getContext(), i, Kind);
-    setAttributes(PAL);
-  }
-
-  /// removes the attribute from the list of attributes.
-  void removeAttribute(unsigned i, StringRef Kind) {
-    AttributeList PAL = getAttributes();
-    PAL = PAL.removeAttribute(getContext(), i, Kind);
-    setAttributes(PAL);
-  }
-
-  /// Removes the attribute from the given argument
-  void removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
-    assert(ArgNo < getNumArgOperands() && "Out of bounds");
-    AttributeList PAL = getAttributes();
-    PAL = PAL.removeParamAttribute(getContext(), ArgNo, Kind);
-    setAttributes(PAL);
-  }
-
-  /// Removes the attribute from the given argument
-  void removeParamAttr(unsigned ArgNo, StringRef Kind) {
-    assert(ArgNo < getNumArgOperands() && "Out of bounds");
-    AttributeList PAL = getAttributes();
-    PAL = PAL.removeParamAttribute(getContext(), ArgNo, Kind);
-    setAttributes(PAL);
-  }
-
-  /// adds the dereferenceable attribute to the list of attributes.
-  void addDereferenceableAttr(unsigned i, uint64_t Bytes) {
-    AttributeList PAL = getAttributes();
-    PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
-    setAttributes(PAL);
-  }
-
-  /// adds the dereferenceable_or_null attribute to the list of
-  /// attributes.
-  void addDereferenceableOrNullAttr(unsigned i, uint64_t Bytes) {
-    AttributeList PAL = getAttributes();
-    PAL = PAL.addDereferenceableOrNullAttr(getContext(), i, Bytes);
-    setAttributes(PAL);
-  }
-
-  /// Determine whether the return value has the given attribute.
-  bool hasRetAttr(Attribute::AttrKind Kind) const {
-    if (Attrs.hasAttribute(AttributeList::ReturnIndex, Kind))
-      return true;
-
-    // Look at the callee, if available.
-    if (const Function *F = getCalledFunction())
-      return F->getAttributes().hasAttribute(AttributeList::ReturnIndex, Kind);
-    return false;
-  }
-
-  /// Determine whether the argument or parameter has the given attribute.
-  bool paramHasAttr(unsigned ArgNo, Attribute::AttrKind Kind) const {
-    assert(ArgNo < getNumArgOperands() && "Param index out of bounds!");
-
-    if (Attrs.hasParamAttribute(ArgNo, Kind))
-      return true;
-    if (const Function *F = getCalledFunction())
-      return F->getAttributes().hasParamAttribute(ArgNo, Kind);
-    return false;
-  }
-
-  /// Get the attribute of a given kind at a position.
-  Attribute getAttribute(unsigned i, Attribute::AttrKind Kind) const {
-    return getAttributes().getAttribute(i, Kind);
-  }
-
-  /// Get the attribute of a given kind at a position.
-  Attribute getAttribute(unsigned i, StringRef Kind) const {
-    return getAttributes().getAttribute(i, Kind);
-  }
-
-  /// Get the attribute of a given kind from a given arg
-  Attribute getParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) const {
-    assert(ArgNo < getNumArgOperands() && "Out of bounds");
-    return getAttributes().getParamAttr(ArgNo, Kind);
-  }
-
-  /// Get the attribute of a given kind from a given arg
-  Attribute getParamAttr(unsigned ArgNo, StringRef Kind) const {
-    assert(ArgNo < getNumArgOperands() && "Out of bounds");
-    return getAttributes().getParamAttr(ArgNo, Kind);
-  }
-  /// Return true if the data operand at index \p i has the attribute \p
-  /// A.
-  ///
-  /// Data operands include call arguments and values used in operand bundles,
-  /// but does not include the callee operand.  This routine dispatches to the
-  /// underlying AttributeList or the OperandBundleUser as appropriate.
-  ///
-  /// The index \p i is interpreted as
-  ///
-  ///  \p i == Attribute::ReturnIndex  -> the return value
-  ///  \p i in [1, arg_size + 1)  -> argument number (\p i - 1)
-  ///  \p i in [arg_size + 1, data_operand_size + 1) -> bundle operand at index
-  ///     (\p i - 1) in the operand list.
-  bool dataOperandHasImpliedAttr(unsigned i, Attribute::AttrKind Kind) const {
-    // There are getNumOperands() - (InstTy::ArgOffset - 1) data operands.
-    // The last operand is the callee.
-    assert(i < (getNumOperands() - InstTy::ArgOffset + 1) &&
-           "Data operand index out of bounds!");
-
-    // The attribute A can either be directly specified, if the operand in
-    // question is a call argument; or be indirectly implied by the kind of its
-    // containing operand bundle, if the operand is a bundle operand.
-
-    if (i == AttributeList::ReturnIndex)
-      return hasRetAttr(Kind);
-
-    // FIXME: Avoid these i - 1 calculations and update the API to use
-    // zero-based indices.
-    if (i < (getNumArgOperands() + 1))
-      return paramHasAttr(i - 1, Kind);
-
-    assert(hasOperandBundles() && i >= (getBundleOperandsStartIndex() + 1) &&
-           "Must be either a call argument or an operand bundle!");
-    return bundleOperandHasAttr(i - 1, Kind);
-  }
-
-  /// Extract the alignment of the return value.
-  unsigned getRetAlignment() const { return Attrs.getRetAlignment(); }
-
-  /// Extract the alignment for a call or parameter (0=unknown).
-  unsigned getParamAlignment(unsigned ArgNo) const {
-    return Attrs.getParamAlignment(ArgNo);
-  }
-
-  /// Extract the number of dereferenceable bytes for a call or
-  /// parameter (0=unknown).
-  uint64_t getDereferenceableBytes(unsigned i) const {
-    return Attrs.getDereferenceableBytes(i);
-  }
-
-  /// Extract the number of dereferenceable_or_null bytes for a call or
-  /// parameter (0=unknown).
-  uint64_t getDereferenceableOrNullBytes(unsigned i) const {
-    return Attrs.getDereferenceableOrNullBytes(i);
-  }
-
-  /// Determine if the return value is marked with NoAlias attribute.
-  bool returnDoesNotAlias() const {
-    return Attrs.hasAttribute(AttributeList::ReturnIndex, Attribute::NoAlias);
-  }
-
-  /// Return true if the call should not be treated as a call to a
-  /// builtin.
-  bool isNoBuiltin() const {
-    return hasFnAttrImpl(Attribute::NoBuiltin) &&
-      !hasFnAttrImpl(Attribute::Builtin);
-  }
-
-  /// Determine if the call requires strict floating point semantics.
-  bool isStrictFP() const { return hasFnAttr(Attribute::StrictFP); }
-
-  /// Return true if the call should not be inlined.
-  bool isNoInline() const { return hasFnAttr(Attribute::NoInline); }
-  void setIsNoInline() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::NoInline);
-  }
-  /// Determine if the call does not access memory.
-  bool doesNotAccessMemory() const {
-    return hasFnAttr(Attribute::ReadNone);
-  }
-  void setDoesNotAccessMemory() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::ReadNone);
-  }
-
-  /// Determine if the call does not access or only reads memory.
-  bool onlyReadsMemory() const {
-    return doesNotAccessMemory() || hasFnAttr(Attribute::ReadOnly);
-  }
-  void setOnlyReadsMemory() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::ReadOnly);
-  }
-
-  /// Determine if the call does not access or only writes memory.
-  bool doesNotReadMemory() const {
-    return doesNotAccessMemory() || hasFnAttr(Attribute::WriteOnly);
-  }
-  void setDoesNotReadMemory() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::WriteOnly);
-  }
-
-  /// Determine if the call can access memmory only using pointers based
-  /// on its arguments.
-  bool onlyAccessesArgMemory() const {
-    return hasFnAttr(Attribute::ArgMemOnly);
-  }
-  void setOnlyAccessesArgMemory() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::ArgMemOnly);
-  }
-
-  /// Determine if the function may only access memory that is
-  /// inaccessible from the IR.
-  bool onlyAccessesInaccessibleMemory() const {
-    return hasFnAttr(Attribute::InaccessibleMemOnly);
-  }
-  void setOnlyAccessesInaccessibleMemory() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::InaccessibleMemOnly);
-  }
-
-  /// Determine if the function may only access memory that is
-  /// either inaccessible from the IR or pointed to by its arguments.
-  bool onlyAccessesInaccessibleMemOrArgMem() const {
-    return hasFnAttr(Attribute::InaccessibleMemOrArgMemOnly);
-  }
-  void setOnlyAccessesInaccessibleMemOrArgMem() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::InaccessibleMemOrArgMemOnly);
-  }
-  /// Determine if the call cannot return.
-  bool doesNotReturn() const { return hasFnAttr(Attribute::NoReturn); }
-  void setDoesNotReturn() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::NoReturn);
-  }
-
-  /// Determine if the call should not perform indirect branch tracking.
-  bool doesNoCfCheck() const { return hasFnAttr(Attribute::NoCfCheck); }
-
-  /// Determine if the call cannot unwind.
-  bool doesNotThrow() const { return hasFnAttr(Attribute::NoUnwind); }
-  void setDoesNotThrow() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
-  }
-
-  /// Determine if the invoke cannot be duplicated.
-  bool cannotDuplicate() const {return hasFnAttr(Attribute::NoDuplicate); }
-  void setCannotDuplicate() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::NoDuplicate);
-  }
-
-  /// Determine if the invoke is convergent
-  bool isConvergent() const { return hasFnAttr(Attribute::Convergent); }
-  void setConvergent() {
-    addAttribute(AttributeList::FunctionIndex, Attribute::Convergent);
-  }
-  void setNotConvergent() {
-    removeAttribute(AttributeList::FunctionIndex, Attribute::Convergent);
-  }
-
-  /// Determine if the call returns a structure through first
-  /// pointer argument.
-  bool hasStructRetAttr() const {
-    if (getNumArgOperands() == 0)
-      return false;
-
-    // Be friendly and also check the callee.
-    return paramHasAttr(0, Attribute::StructRet);
-  }
-
-  /// Determine if any call argument is an aggregate passed by value.
-  bool hasByValArgument() const {
-    return Attrs.hasAttrSomewhere(Attribute::ByVal);
-  }
-  /// Get a pointer to the function that is invoked by this
-  /// instruction.
-  const Value *getCalledValue() const { return Op<-InstTy::ArgOffset>(); }
-  Value *getCalledValue() { return Op<-InstTy::ArgOffset>(); }
-
-  /// Set the function called.
-  void setCalledFunction(Value* Fn) {
-    setCalledFunction(
-        cast<FunctionType>(cast<PointerType>(Fn->getType())->getElementType()),
-        Fn);
-  }
-  void setCalledFunction(FunctionType *FTy, Value *Fn) {
-    this->FTy = FTy;
-    assert(FTy == cast<FunctionType>(
-                      cast<PointerType>(Fn->getType())->getElementType()));
-    Op<-InstTy::ArgOffset>() = Fn;
-  }
-
-protected:
-  template <typename AttrKind> bool hasFnAttrImpl(AttrKind Kind) const {
-    if (Attrs.hasAttribute(AttributeList::FunctionIndex, Kind))
-      return true;
-
-    // Operand bundles override attributes on the called function, but don't
-    // override attributes directly present on the call instruction.
-    if (isFnAttrDisallowedByOpBundle(Kind))
-      return false;
-
-    if (const Function *F = getCalledFunction())
-      return F->getAttributes().hasAttribute(AttributeList::FunctionIndex,
-                                             Kind);
-    return false;
-  }
-};
-
 //===----------------------------------------------------------------------===//
 /// This class represents a function call, abstracting a target
 /// machine's calling convention.  This class uses low bit of the SubClassData
 /// field to indicate whether or not this is a tail call.  The rest of the bits
 /// hold the calling convention of the call.
 ///
-class CallInst : public CallBase<CallInst> {
-  friend class OperandBundleUser<CallInst, User::op_iterator>;
-
+class CallInst : public CallBase {
   CallInst(const CallInst &CI);
 
   /// Construct a CallInst given a range of arguments.
   /// Construct a CallInst from a range of arguments
   inline CallInst(FunctionType *Ty, Value *Func, ArrayRef<Value *> Args,
                   ArrayRef<OperandBundleDef> Bundles, const Twine &NameStr,
                   Instruction *InsertBefore);
 
void init(Value *Func, ArrayRef<Value *> Args,
     init(cast<FunctionType>(
              cast<PointerType>(Func->getType())->getElementType()),
          Func, Args, Bundles, NameStr);
   }
   void init(FunctionType *FTy, Value *Func, ArrayRef<Value *> Args,
             ArrayRef<OperandBundleDef> Bundles, const Twine &NameStr);
   void init(Value *Func, const Twine &NameStr);
 
+  /// Compute the number of operands to allocate.
+  static int ComputeNumOperands(int NumArgs, int NumBundleInputs = 0) {
+    // We need one operand for the called function, plus the input operand
+    // counts provided.
+    return 1 + NumArgs + NumBundleInputs;
+  }
+
 protected:
   // Note: Instruction needs to be a friend here to call cloneImpl.
   friend class Instruction;
 
   CallInst *cloneImpl() const;
 
 public:
-  static constexpr int ArgOffset = 1;
-
   static CallInst *Create(Value *Func, ArrayRef<Value *> Args,
                           ArrayRef<OperandBundleDef> Bundles = None,
                           const Twine &NameStr = "",
                           Instruction *InsertBefore = nullptr) {
     return Create(cast<FunctionType>(
                       cast<PointerType>(Func->getType())->getElementType()),
                   Func, Args, Bundles, NameStr, InsertBefore);
   }
 
   static CallInst *Create(Value *Func, ArrayRef<Value *> Args,
                           const Twine &NameStr,
                           Instruction *InsertBefore = nullptr) {
     return Create(cast<FunctionType>(
                       cast<PointerType>(Func->getType())->getElementType()),
                   Func, Args, None, NameStr, InsertBefore);
   }
 
   static CallInst *Create(FunctionType *Ty, Value *Func, ArrayRef<Value *> Args,
                           const Twine &NameStr,
                           Instruction *InsertBefore = nullptr) {
-    return new (unsigned(Args.size() + 1))
+    return new (ComputeNumOperands(Args.size()))
         CallInst(Ty, Func, Args, None, NameStr, InsertBefore);
   }
 
   static CallInst *Create(FunctionType *Ty, Value *Func, ArrayRef<Value *> Args,
                           ArrayRef<OperandBundleDef> Bundles = None,
                           const Twine &NameStr = "",
                           Instruction *InsertBefore = nullptr) {
-    const unsigned TotalOps =
-        unsigned(Args.size()) + CountBundleInputs(Bundles) + 1;
+    const int NumOperands =
+        ComputeNumOperands(Args.size(), CountBundleInputs(Bundles));
     const unsigned DescriptorBytes = Bundles.size() * sizeof(BundleOpInfo);
 
-    return new (TotalOps, DescriptorBytes)
+    return new (NumOperands, DescriptorBytes)
         CallInst(Ty, Func, Args, Bundles, NameStr, InsertBefore);
   }
 
   static CallInst *Create(Value *Func, ArrayRef<Value *> Args,
                           ArrayRef<OperandBundleDef> Bundles,
                           const Twine &NameStr, BasicBlock *InsertAtEnd) {
-    const unsigned TotalOps =
-        unsigned(Args.size()) + CountBundleInputs(Bundles) + 1;
+    const int NumOperands =
+        ComputeNumOperands(Args.size(), CountBundleInputs(Bundles));
     const unsigned DescriptorBytes = Bundles.size() * sizeof(BundleOpInfo);
 
-    return new (TotalOps, DescriptorBytes)
+    return new (NumOperands, DescriptorBytes)
         CallInst(Func, Args, Bundles, NameStr, InsertAtEnd);
   }
 
   static CallInst *Create(Value *Func, ArrayRef<Value *> Args,
                           const Twine &NameStr, BasicBlock *InsertAtEnd) {
-    return new (unsigned(Args.size() + 1))
+    return new (ComputeNumOperands(Args.size()))
         CallInst(Func, Args, None, NameStr, InsertAtEnd);
   }
 
   static CallInst *Create(Value *F, const Twine &NameStr = "",
                           Instruction *InsertBefore = nullptr) {
-    return new (1) CallInst(F, NameStr, InsertBefore);
+    return new (ComputeNumOperands(0)) CallInst(F, NameStr, InsertBefore);
   }
 
   static CallInst *Create(Value *F, const Twine &NameStr,
                           BasicBlock *InsertAtEnd) {
-    return new (1) CallInst(F, NameStr, InsertAtEnd);
+    return new (ComputeNumOperands(0)) CallInst(F, NameStr, InsertAtEnd);
   }
 
   /// Create a clone of \p CI with a different set of operand bundles and
   /// insert it before \p InsertPt.
   ///
   /// The returned call instruction is identical \p CI in every way except that
   /// the operand bundles for the new instruction are set to the operand bundles
   /// in \p Bundles.
public:
 
   /// Return true if the call can return twice
   bool canReturnTwice() const { return hasFnAttr(Attribute::ReturnsTwice); }
   void setCanReturnTwice() {
     addAttribute(AttributeList::FunctionIndex, Attribute::ReturnsTwice);
   }
 
   /// Check if this call is an inline asm statement.
-  bool isInlineAsm() const { return isa<InlineAsm>(Op<-1>()); }
+  bool isInlineAsm() const { return isa<InlineAsm>(getCalledOperand()); }
 
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Instruction *I) {
     return I->getOpcode() == Instruction::Call;
   }
   static bool classof(const Value *V) {
     return isa<Instruction>(V) && classof(cast<Instruction>(V));
   }
 
 private:
   // Shadow Instruction::setInstructionSubclassData with a private forwarding
   // method so that subclasses cannot accidentally use it.
   void setInstructionSubclassData(unsigned short D) {
     Instruction::setInstructionSubclassData(D);
   }
 };
 
-template <>
-struct OperandTraits<CallBase<CallInst>>
-    : public VariadicOperandTraits<CallBase<CallInst>, 1> {};
-
 CallInst::CallInst(Value *Func, ArrayRef<Value *> Args,
                    ArrayRef<OperandBundleDef> Bundles, const Twine &NameStr,
                    BasicBlock *InsertAtEnd)
-    : CallBase<CallInst>(
-          cast<FunctionType>(
+    : CallBase(cast<FunctionType>(
                    cast<PointerType>(Func->getType())->getElementType())
                    ->getReturnType(),
                Instruction::Call,
-          OperandTraits<CallBase<CallInst>>::op_end(this) -
+               OperandTraits<CallBase>::op_end(this) -
                    (Args.size() + CountBundleInputs(Bundles) + 1),
-          unsigned(Args.size() + CountBundleInputs(Bundles) + 1), InsertAtEnd) {
+               unsigned(Args.size() + CountBundleInputs(Bundles) + 1),
+               InsertAtEnd) {
   init(Func, Args, Bundles, NameStr);
 }
 
 CallInst::CallInst(FunctionType *Ty, Value *Func, ArrayRef<Value *> Args,
                    ArrayRef<OperandBundleDef> Bundles, const Twine &NameStr,
                    Instruction *InsertBefore)
-    : CallBase<CallInst>(Ty->getReturnType(), Instruction::Call,
-                         OperandTraits<CallBase<CallInst>>::op_end(this) -
-                             (Args.size() + CountBundleInputs(Bundles) + 1),
-                         unsigned(Args.size() + CountBundleInputs(Bundles) + 1),
-                         InsertBefore) {
+    : CallBase(Ty->getReturnType(), Instruction::Call,
+               OperandTraits<CallBase>::op_end(this) -
   init(Ty, Func, Args, Bundles, NameStr);
 }
 
 //===----------------------------------------------------------------------===//
 //                               SelectInst Class
 //===----------------------------------------------------------------------===//
 
 /// This class represents the LLVM 'select' instruction.

 
 //===----------------------------------------------------------------------===//
 //                               InvokeInst Class
 //===----------------------------------------------------------------------===//
 
 /// Invoke instruction.  The SubclassData field is used to hold the
 /// calling convention of the call.
 ///
-class InvokeInst : public CallBase<InvokeInst> {
-  friend class OperandBundleUser<InvokeInst, User::op_iterator>;
+class InvokeInst : public CallBase {
+  /// The number of operands for this call beyond the called function,
+  /// arguments, and operand bundles.
+  static constexpr int NumExtraOperands = 2;
+
+  /// The index from the end of the operand array to the normal destination.
+  static constexpr int NormalDestOpEndIdx = -3;
+
+  /// The index from the end of the operand array to the unwind destination.
+  static constexpr int UnwindDestOpEndIdx = -2;
 
   InvokeInst(const InvokeInst &BI);
 
   /// Construct an InvokeInst given a range of arguments.
   ///
   /// Construct an InvokeInst from a range of arguments
   inline InvokeInst(Value *Func, BasicBlock *IfNormal, BasicBlock *IfException,
                     ArrayRef<Value *> Args, ArrayRef<OperandBundleDef> Bundles,
-                    unsigned Values, const Twine &NameStr,
+                    int NumOperands, const Twine &NameStr,
                     Instruction *InsertBefore)
       : InvokeInst(cast<FunctionType>(
                        cast<PointerType>(Func->getType())->getElementType()),
-                   Func, IfNormal, IfException, Args, Bundles, Values, NameStr,
-                   InsertBefore) {}
+                   Func, IfNormal, IfException, Args, Bundles, NumOperands,
+                   NameStr, InsertBefore) {}
 
   inline InvokeInst(FunctionType *Ty, Value *Func, BasicBlock *IfNormal,
                     BasicBlock *IfException, ArrayRef<Value *> Args,
-                    ArrayRef<OperandBundleDef> Bundles, unsigned Values,
+                    ArrayRef<OperandBundleDef> Bundles, int NumOperands,
                     const Twine &NameStr, Instruction *InsertBefore);
   /// Construct an InvokeInst given a range of arguments.
   ///
   /// Construct an InvokeInst from a range of arguments
   inline InvokeInst(Value *Func, BasicBlock *IfNormal, BasicBlock *IfException,
                     ArrayRef<Value *> Args, ArrayRef<OperandBundleDef> Bundles,
-                    unsigned Values, const Twine &NameStr,
+                    int NumOperands, const Twine &NameStr,
                     BasicBlock *InsertAtEnd);
 
-
   void init(Value *Func, BasicBlock *IfNormal, BasicBlock *IfException,
             ArrayRef<Value *> Args, ArrayRef<OperandBundleDef> Bundles,
             const Twine &NameStr) {
     init(cast<FunctionType>(
              cast<PointerType>(Func->getType())->getElementType()),
          Func, IfNormal, IfException, Args, Bundles, NameStr);
   }
 
   void init(FunctionType *FTy, Value *Func, BasicBlock *IfNormal,
             BasicBlock *IfException, ArrayRef<Value *> Args,
             ArrayRef<OperandBundleDef> Bundles, const Twine &NameStr);
 
+  /// Compute the number of operands to allocate.
+  static int ComputeNumOperands(int NumArgs, int NumBundleInputs = 0) {
+    // We need one operand for the called function, plus our extra operands and
+    // the input operand counts provided.
+    return 1 + NumExtraOperands + NumArgs + NumBundleInputs;
+  }
+
 protected:
   // Note: Instruction needs to be a friend here to call cloneImpl.
   friend class Instruction;
 
   InvokeInst *cloneImpl() const;
 
 public:
-  static constexpr int ArgOffset = 3;
   static InvokeInst *Create(Value *Func, BasicBlock *IfNormal,
                             BasicBlock *IfException, ArrayRef<Value *> Args,
                             const Twine &NameStr,
                             Instruction *InsertBefore = nullptr) {
     return Create(cast<FunctionType>(
                       cast<PointerType>(Func->getType())->getElementType()),
                   Func, IfNormal, IfException, Args, None, NameStr,
                   InsertBefore);
return Create(cast<FunctionType>(
                   Func, IfNormal, IfException, Args, Bundles, NameStr,
                   InsertBefore);
   }
 
   static InvokeInst *Create(FunctionType *Ty, Value *Func, BasicBlock *IfNormal,
                             BasicBlock *IfException, ArrayRef<Value *> Args,
                             const Twine &NameStr,
                             Instruction *InsertBefore = nullptr) {
-    unsigned Values = unsigned(Args.size()) + 3;
-    return new (Values) InvokeInst(Ty, Func, IfNormal, IfException, Args, None,
-                                   Values, NameStr, InsertBefore);
+    int NumOperands = ComputeNumOperands(Args.size());
+    return new (NumOperands)
+        InvokeInst(Ty, Func, IfNormal, IfException, Args, None, NumOperands,
+                   NameStr, InsertBefore);
   }
 
   static InvokeInst *Create(FunctionType *Ty, Value *Func, BasicBlock *IfNormal,
                             BasicBlock *IfException, ArrayRef<Value *> Args,
                             ArrayRef<OperandBundleDef> Bundles = None,
                             const Twine &NameStr = "",
                             Instruction *InsertBefore = nullptr) {
-    unsigned Values = unsigned(Args.size()) + CountBundleInputs(Bundles) + 3;
+    int NumOperands =
+        ComputeNumOperands(Args.size(), CountBundleInputs(Bundles));
     unsigned DescriptorBytes = Bundles.size() * sizeof(BundleOpInfo);
 
-    return new (Values, DescriptorBytes)
-        InvokeInst(Ty, Func, IfNormal, IfException, Args, Bundles, Values,
+    return new (NumOperands, DescriptorBytes)
+        InvokeInst(Ty, Func, IfNormal, IfException, Args, Bundles, NumOperands,
                    NameStr, InsertBefore);
   }
 
   static InvokeInst *Create(Value *Func,
                             BasicBlock *IfNormal, BasicBlock *IfException,
                             ArrayRef<Value *> Args, const Twine &NameStr,
                             BasicBlock *InsertAtEnd) {
-    unsigned Values = unsigned(Args.size()) + 3;
-    return new (Values) InvokeInst(Func, IfNormal, IfException, Args, None,
-                                   Values, NameStr, InsertAtEnd);
+    int NumOperands = ComputeNumOperands(Args.size());
+    return new (NumOperands) InvokeInst(Func, IfNormal, IfException, Args, None,
+                                        NumOperands, NameStr, InsertAtEnd);
   }
 
   static InvokeInst *Create(Value *Func, BasicBlock *IfNormal,
                             BasicBlock *IfException, ArrayRef<Value *> Args,
                             ArrayRef<OperandBundleDef> Bundles,
                             const Twine &NameStr, BasicBlock *InsertAtEnd) {
-    unsigned Values = unsigned(Args.size()) + CountBundleInputs(Bundles) + 3;
+    int NumOperands =
+        ComputeNumOperands(Args.size(), CountBundleInputs(Bundles));
     unsigned DescriptorBytes = Bundles.size() * sizeof(BundleOpInfo);
 
-    return new (Values, DescriptorBytes)
-        InvokeInst(Func, IfNormal, IfException, Args, Bundles, Values, NameStr,
-                   InsertAtEnd);
+    return new (NumOperands, DescriptorBytes)
+        InvokeInst(Func, IfNormal, IfException, Args, Bundles, NumOperands,
+                   NameStr, InsertAtEnd);
   }
 
   /// Create a clone of \p II with a different set of operand bundles and
   /// insert it before \p InsertPt.
   ///
   /// The returned invoke instruction is identical to \p II in every way except
   /// that the operand bundles for the new instruction are set to the operand
   /// bundles in \p Bundles.
   static InvokeInst *Create(InvokeInst *II, ArrayRef<OperandBundleDef> Bundles,
                             Instruction *InsertPt = nullptr);
 
   /// Determine if the call should not perform indirect branch tracking.
   bool doesNoCfCheck() const { return hasFnAttr(Attribute::NoCfCheck); }
 
   /// Determine if the call cannot unwind.
   bool doesNotThrow() const { return hasFnAttr(Attribute::NoUnwind); }
   void setDoesNotThrow() {
     addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
   }
 
-  /// Return the function called, or null if this is an
-  /// indirect function invocation.
-  ///
-  Function *getCalledFunction() const {
-    return dyn_cast<Function>(Op<-3>());
-  }
-
-  /// Get a pointer to the function that is invoked by this
-  /// instruction
-  const Value *getCalledValue() const { return Op<-3>(); }
-        Value *getCalledValue()       { return Op<-3>(); }
-
-  /// Set the function called.
-  void setCalledFunction(Value* Fn) {
-    setCalledFunction(
-        cast<FunctionType>(cast<PointerType>(Fn->getType())->getElementType()),
-        Fn);
-  }
-  void setCalledFunction(FunctionType *FTy, Value *Fn) {
-    this->FTy = FTy;
-    assert(FTy == cast<FunctionType>(
-                      cast<PointerType>(Fn->getType())->getElementType()));
-    Op<-3>() = Fn;
-  }
-
   // get*Dest - Return the destination basic blocks...
   BasicBlock *getNormalDest() const {
-    return cast<BasicBlock>(Op<-2>());
+    return cast<BasicBlock>(Op<NormalDestOpEndIdx>());
   }
   BasicBlock *getUnwindDest() const {
-    return cast<BasicBlock>(Op<-1>());
+    return cast<BasicBlock>(Op<UnwindDestOpEndIdx>());
   }
   void setNormalDest(BasicBlock *B) {
-    Op<-2>() = reinterpret_cast<Value*>(B);
+    Op<NormalDestOpEndIdx>() = reinterpret_cast<Value *>(B);
   }
   void setUnwindDest(BasicBlock *B) {
-    Op<-1>() = reinterpret_cast<Value*>(B);
+    Op<UnwindDestOpEndIdx>() = reinterpret_cast<Value *>(B);
   }
 
   /// Get the landingpad instruction from the landing pad
   /// block (the unwind destination).
   LandingPadInst *getLandingPadInst() const;
 
   BasicBlock *getSuccessor(unsigned i) const {
     assert(i < 2 && "Successor # out of range for invoke!");
     return i == 0 ? getNormalDest() : getUnwindDest();
   }
 
-  void setSuccessor(unsigned idx, BasicBlock *NewSucc) {
-    assert(idx < 2 && "Successor # out of range for invoke!");
-    *(&Op<-2>() + idx) = reinterpret_cast<Value*>(NewSucc);
+  void setSuccessor(unsigned i, BasicBlock *NewSucc) {
+    assert(i < 2 && "Successor # out of range for invoke!");
+    if (i == 0)
+      setNormalDest(NewSucc);
+    else
+      setUnwindDest(NewSucc);
   }
 
   unsigned getNumSuccessors() const { return 2; }
 
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Instruction *I) {
     return (I->getOpcode() == Instruction::Invoke);
   }
   static bool classof(const Value *V) {
     return isa<Instruction>(V) && classof(cast<Instruction>(V));
   }
 
 private:
 
   // Shadow Instruction::setInstructionSubclassData with a private forwarding
   // method so that subclasses cannot accidentally use it.
   void setInstructionSubclassData(unsigned short D) {
     Instruction::setInstructionSubclassData(D);
   }
 };
 
-template <>
-struct OperandTraits<CallBase<InvokeInst>>
-    : public VariadicOperandTraits<CallBase<InvokeInst>, 3> {};
-
 InvokeInst::InvokeInst(FunctionType *Ty, Value *Func, BasicBlock *IfNormal,
                        BasicBlock *IfException, ArrayRef<Value *> Args,
-                       ArrayRef<OperandBundleDef> Bundles, unsigned Values,
+                       ArrayRef<OperandBundleDef> Bundles, int NumOperands,
                        const Twine &NameStr, Instruction *InsertBefore)
-    : CallBase<InvokeInst>(Ty->getReturnType(), Instruction::Invoke,
-                           OperandTraits<CallBase<InvokeInst>>::op_end(this) -
-                               Values,
-                           Values, InsertBefore) {
+    : CallBase(Ty->getReturnType(), Instruction::Invoke,
+               OperandTraits<CallBase>::op_end(this) - NumOperands, NumOperands,
+               InsertBefore) {
   init(Ty, Func, IfNormal, IfException, Args, Bundles, NameStr);
 }
 
 InvokeInst::InvokeInst(Value *Func, BasicBlock *IfNormal,
                        BasicBlock *IfException, ArrayRef<Value *> Args,
-                       ArrayRef<OperandBundleDef> Bundles, unsigned Values,
+                       ArrayRef<OperandBundleDef> Bundles, int NumOperands,
                        const Twine &NameStr, BasicBlock *InsertAtEnd)
-    : CallBase<InvokeInst>(
-          cast<FunctionType>(
+    : CallBase(cast<FunctionType>(
                    cast<PointerType>(Func->getType())->getElementType())
                    ->getReturnType(),
                Instruction::Invoke,
-          OperandTraits<CallBase<InvokeInst>>::op_end(this) - Values, Values,
+               OperandTraits<CallBase>::op_end(this) - NumOperands, NumOperands,
                InsertAtEnd) {
   init(Func, IfNormal, IfException, Args, Bundles, NameStr);
 }
 
-
 //===----------------------------------------------------------------------===//
 //                              ResumeInst Class
 //===----------------------------------------------------------------------===//
 
 //===---------------------------------------------------------------------------
 /// Resume the propagation of an exception.
 ///
 class ResumeInst : public Instruction {

llvm/lib/IR/Instructions.cpp

AllocaInst::getAllocationSizeInBits(const DataLayout &DL) const {
   return Size;
 }
 
 //===----------------------------------------------------------------------===//
 //                            CallSite Class
 //===----------------------------------------------------------------------===//
 
 User::op_iterator CallSite::getCallee() const {
-  Instruction *II(getInstruction());
-  return isCall()
-    ? cast<CallInst>(II)->op_end() - 1 // Skip Callee
-    : cast<InvokeInst>(II)->op_end() - 3; // Skip BB, BB, Callee
+  return cast<CallBase>(getInstruction())->op_end() - 1;
 }
 
 //===----------------------------------------------------------------------===//
 //                              SelectInst Class
 //===----------------------------------------------------------------------===//
 
 /// areInvalidOperands - Return a string if the specified operands are invalid
 /// for a select operation, otherwise return null.
void LandingPadInst::addClause(Constant *Val) {
   unsigned OpNo = getNumOperands();
   growOperands(1);
   assert(OpNo < ReservedSpace && "Growing didn't work!");
   setNumHungOffUseOperands(getNumOperands() + 1);
   getOperandList()[OpNo] = Val;
 }
 
 //===----------------------------------------------------------------------===//
+//                        CallBase Implementation
+//===----------------------------------------------------------------------===//
+
+Value *CallBase::getReturnedArgOperand() const {
+  unsigned Index;
+
+  if (Attrs.hasAttrSomewhere(Attribute::Returned, &Index) && Index)
+    return getArgOperand(Index - AttributeList::FirstArgIndex);
+  if (const Function *F = getCalledFunction())
+    if (F->getAttributes().hasAttrSomewhere(Attribute::Returned, &Index) &&
+        Index)
+      return getArgOperand(Index - AttributeList::FirstArgIndex);
+
+  return nullptr;
+}
+
+bool CallBase::hasRetAttr(Attribute::AttrKind Kind) const {
+  if (Attrs.hasAttribute(AttributeList::ReturnIndex, Kind))
+    return true;
+
+  // Look at the callee, if available.
+  if (const Function *F = getCalledFunction())
+    return F->getAttributes().hasAttribute(AttributeList::ReturnIndex, Kind);
+  return false;
+}
+
+/// Determine whether the argument or parameter has the given attribute.
+bool CallBase::paramHasAttr(unsigned ArgNo, Attribute::AttrKind Kind) const {
+  assert(ArgNo < getNumArgOperands() && "Param index out of bounds!");
+
+  if (Attrs.hasParamAttribute(ArgNo, Kind))
+    return true;
+  if (const Function *F = getCalledFunction())
+    return F->getAttributes().hasParamAttribute(ArgNo, Kind);
+  return false;
+}
+
+bool CallBase::hasFnAttrOnCalledFunction(Attribute::AttrKind Kind) const {
+  if (const Function *F = getCalledFunction())
+    return F->getAttributes().hasAttribute(AttributeList::FunctionIndex, Kind);
+  return false;
+}
+
+bool CallBase::hasFnAttrOnCalledFunction(StringRef Kind) const {
+  if (const Function *F = getCalledFunction())
+    return F->getAttributes().hasAttribute(AttributeList::FunctionIndex, Kind);
+  return false;
+}
+
+CallBase::op_iterator
+CallBase::populateBundleOperandInfos(ArrayRef<OperandBundleDef> Bundles,
+                                     const unsigned BeginIndex) {
+  auto It = op_begin() + BeginIndex;
+  for (auto &B : Bundles)
+    It = std::copy(B.input_begin(), B.input_end(), It);
+
+  auto *ContextImpl = getContext().pImpl;
+  auto BI = Bundles.begin();
+  unsigned CurrentIndex = BeginIndex;
+
+  for (auto &BOI : bundle_op_infos()) {
+    assert(BI != Bundles.end() && "Incorrect allocation?");
+
+    BOI.Tag = ContextImpl->getOrInsertBundleTag(BI->getTag());
+    BOI.Begin = CurrentIndex;
+    BOI.End = CurrentIndex + BI->input_size();
+    CurrentIndex = BOI.End;
+    BI++;
+  }
+
+  assert(BI == Bundles.end() && "Incorrect allocation?");
+
+  return It;
+}
+
+//===----------------------------------------------------------------------===//
 //                        CallInst Implementation
 //===----------------------------------------------------------------------===//
 
 void CallInst::init(FunctionType *FTy, Value *Func, ArrayRef<Value *> Args,
                     ArrayRef<OperandBundleDef> Bundles, const Twine &NameStr) {
   this->FTy = FTy;
   assert(getNumOperands() == Args.size() + CountBundleInputs(Bundles) + 1 &&
          "NumOperands not set up?");
-  Op<-1>() = Func;
+  setCalledOperand(Func);
 
 #ifndef NDEBUG
   assert((Args.size() == FTy->getNumParams() ||
           (FTy->isVarArg() && Args.size() > FTy->getNumParams())) &&
          "Calling a function with bad signature!");
 
   for (unsigned i = 0; i != Args.size(); ++i)
     assert((i >= FTy->getNumParams() ||
#endif
 
   setName(NameStr);
 }
 
 void CallInst::init(Value *Func, const Twine &NameStr) {
   FTy =
       cast<FunctionType>(cast<PointerType>(Func->getType())->getElementType());
   assert(getNumOperands() == 1 && "NumOperands not set up?");
-  Op<-1>() = Func;
+  setCalledOperand(Func);
 
   assert(FTy->getNumParams() == 0 && "Calling a function with bad signature");
 
   setName(NameStr);
 }
 
 CallInst::CallInst(Value *Func, const Twine &Name, Instruction *InsertBefore)
-    : CallBase<CallInst>(
-          cast<FunctionType>(
+    : CallBase(cast<FunctionType>(
                    cast<PointerType>(Func->getType())->getElementType())
                    ->getReturnType(),
-          Instruction::Call,
-          OperandTraits<CallBase<CallInst>>::op_end(this) - 1, 1,
+               Instruction::Call, OperandTraits<CallBase>::op_end(this) - 1, 1,
                InsertBefore) {
   init(Func, Name);
 }
 
 CallInst::CallInst(Value *Func, const Twine &Name, BasicBlock *InsertAtEnd)
-    : CallBase<CallInst>(
-          cast<FunctionType>(
+    : CallBase(cast<FunctionType>(
                    cast<PointerType>(Func->getType())->getElementType())
                    ->getReturnType(),
-          Instruction::Call,
-          OperandTraits<CallBase<CallInst>>::op_end(this) - 1, 1, InsertAtEnd) {
+               Instruction::Call, OperandTraits<CallBase>::op_end(this) - 1, 1,
+               InsertAtEnd) {
   init(Func, Name);
 }
 
 CallInst::CallInst(const CallInst &CI)
-    : CallBase<CallInst>(CI.Attrs, CI.FTy, CI.getType(), Instruction::Call,
-                         OperandTraits<CallBase<CallInst>>::op_end(this) -
-                             CI.getNumOperands(),
-                         CI.getNumOperands()) {
+    : CallBase(CI.Attrs, CI.FTy, CI.getType(), Instruction::Call,
+               OperandTraits<CallBase>::op_end(this) - CI.getNumOperands(),
   setTailCallKind(CI.getTailCallKind());
   setCallingConv(CI.getCallingConv());
 
   std::copy(CI.op_begin(), CI.op_end(), op_begin());
   std::copy(CI.bundle_op_info_begin(), CI.bundle_op_info_end(),
             bundle_op_info_begin());
   SubclassOptionalData = CI.SubclassOptionalData;
 }

 //===----------------------------------------------------------------------===//
 
 void InvokeInst::init(FunctionType *FTy, Value *Fn, BasicBlock *IfNormal,
                       BasicBlock *IfException, ArrayRef<Value *> Args,
                       ArrayRef<OperandBundleDef> Bundles,
                       const Twine &NameStr) {
   this->FTy = FTy;
 
-  assert(getNumOperands() == 3 + Args.size() + CountBundleInputs(Bundles) &&
+  assert((int)getNumOperands() ==
+             ComputeNumOperands(Args.size(), CountBundleInputs(Bundles)) &&
          "NumOperands not set up?");
-  Op<-3>() = Fn;
-  Op<-2>() = IfNormal;
-  Op<-1>() = IfException;
+  setNormalDest(IfNormal);
+  setUnwindDest(IfException);
+  setCalledOperand(Fn);
 
 #ifndef NDEBUG
   assert(((Args.size() == FTy->getNumParams()) ||
           (FTy->isVarArg() && Args.size() > FTy->getNumParams())) &&
          "Invoking a function with bad signature");
 
   for (unsigned i = 0, e = Args.size(); i != e; i++)
     assert((i >= FTy->getNumParams() ||
             FTy->getParamType(i) == Args[i]->getType()) &&
            "Invoking a function with a bad signature!");
 #endif
 
   llvm::copy(Args, op_begin());
 
   auto It = populateBundleOperandInfos(Bundles, Args.size());
   (void)It;
   assert(It + 3 == op_end() && "Should add up!");
 
   setName(NameStr);
 }
 
 InvokeInst::InvokeInst(const InvokeInst &II)
-    : CallBase<InvokeInst>(II.Attrs, II.FTy, II.getType(), Instruction::Invoke,
-                           OperandTraits<CallBase<InvokeInst>>::op_end(this) -
-                               II.getNumOperands(),
-                           II.getNumOperands()) {
+    : CallBase(II.Attrs, II.FTy, II.getType(), Instruction::Invoke,
+               OperandTraits<CallBase>::op_end(this) - II.getNumOperands(),
   setCallingConv(II.getCallingConv());
   std::copy(II.op_begin(), II.op_end(), op_begin());
   std::copy(II.bundle_op_info_begin(), II.bundle_op_info_end(),
             bundle_op_info_begin());
   SubclassOptionalData = II.SubclassOptionalData;
 }
 
 InvokeInst *InvokeInst::Create(InvokeInst *II, ArrayRef<OperandBundleDef> OpB,

llvm/lib/IR/Verifier.cpp

if (Instruction *Used = dyn_cast<Instruction>(U.getUser()))
              " instruction not embedded in a basic block!",
              &I, Used);
     else {
       CheckFailed("Use of instruction is not an instruction!", U);
       return;
     }
   }
 
+  // Get a pointer to the call base of the instruction if it is some form of
+  // call.
+  const CallBase *CBI = dyn_cast<CallBase>(&I);
+
   for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
     Assert(I.getOperand(i) != nullptr, "Instruction has null operand!", &I);
 
     // Check to make sure that only first-class-values are operands to
     // instructions.
     if (!I.getOperand(i)->getType()->isFirstClassType()) {
       Assert(false, "Instruction operands must be first-class values!", &I);
     }
 
     if (Function *F = dyn_cast<Function>(I.getOperand(i))) {
       // Check to make sure that the "address of" an intrinsic function is never
       // taken.
-      Assert(
-          !F->isIntrinsic() ||
-              i == (isa<CallInst>(I) ? e - 1 : isa<InvokeInst>(I) ? e - 3 : 0),
+      Assert(!F->isIntrinsic() ||
+                 (CBI && &CBI->getCalledOperandUse() == &I.getOperandUse(i)),
              "Cannot take the address of an intrinsic!", &I);
       Assert(
           !F->isIntrinsic() || isa<CallInst>(I) ||
               F->getIntrinsicID() == Intrinsic::donothing ||
               F->getIntrinsicID() == Intrinsic::coro_resume ||
               F->getIntrinsicID() == Intrinsic::coro_destroy ||
               F->getIntrinsicID() == Intrinsic::experimental_patchpoint_void ||
               F->getIntrinsicID() == Intrinsic::experimental_patchpoint_i64 ||
               F->getIntrinsicID() == Intrinsic::experimental_gc_statepoint,
if (Function *F = dyn_cast<Function>(I.getOperand(i))) {
       Assert(OpArg->getParent() == BB->getParent(),
              "Referring to an argument in another function!", &I);
     } else if (GlobalValue *GV = dyn_cast<GlobalValue>(I.getOperand(i))) {
       Assert(GV->getParent() == &M, "Referencing global in another module!", &I,
              &M, GV, GV->getParent());
     } else if (isa<Instruction>(I.getOperand(i))) {
       verifyDominatesUse(I, i);
     } else if (isa<InlineAsm>(I.getOperand(i))) {
-      Assert((i + 1 == e && isa<CallInst>(I)) ||
-                 (i + 3 == e && isa<InvokeInst>(I)),
+      Assert(CBI && &CBI->getCalledOperandUse() == &I.getOperandUse(i),
              "Cannot take the address of an inline asm!", &I);
     } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(I.getOperand(i))) {
       if (CE->getType()->isPtrOrPtrVectorTy() ||
           !DL.getNonIntegralAddressSpaces().empty()) {
         // If we have a ConstantExpr pointer, we need to see if it came from an
         // illegal bitcast.  If the datalayout string specifies non-integral
         // address spaces then we also need to check for illegal ptrtoint and
         // inttoptr expressions.