1 //===-- Analysis.cpp - CodeGen LLVM IR Analysis Utilities -----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines several CodeGen-specific LLVM IR analysis utilities.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/Analysis.h"
15 #include "llvm/Analysis/ValueTracking.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/CodeGen/SelectionDAG.h"
18 #include "llvm/IR/DataLayout.h"
19 #include "llvm/IR/DerivedTypes.h"
20 #include "llvm/IR/Function.h"
21 #include "llvm/IR/Instructions.h"
22 #include "llvm/IR/IntrinsicInst.h"
23 #include "llvm/IR/LLVMContext.h"
24 #include "llvm/IR/Module.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/MathExtras.h"
27 #include "llvm/Target/TargetLowering.h"
30 /// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
31 /// of insertvalue or extractvalue indices that identify a member, return
32 /// the linearized index of the start of the member.
34 unsigned llvm::ComputeLinearIndex(Type *Ty,
35 const unsigned *Indices,
36 const unsigned *IndicesEnd,
38 // Base case: We're done.
39 if (Indices && Indices == IndicesEnd)
42 // Given a struct type, recursively traverse the elements.
43 if (StructType *STy = dyn_cast<StructType>(Ty)) {
44 for (StructType::element_iterator EB = STy->element_begin(),
46 EE = STy->element_end();
48 if (Indices && *Indices == unsigned(EI - EB))
49 return ComputeLinearIndex(*EI, Indices+1, IndicesEnd, CurIndex);
50 CurIndex = ComputeLinearIndex(*EI, nullptr, nullptr, CurIndex);
54 // Given an array type, recursively traverse the elements.
55 else if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
56 Type *EltTy = ATy->getElementType();
57 for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i) {
58 if (Indices && *Indices == i)
59 return ComputeLinearIndex(EltTy, Indices+1, IndicesEnd, CurIndex);
60 CurIndex = ComputeLinearIndex(EltTy, nullptr, nullptr, CurIndex);
64 // We haven't found the type we're looking for, so keep searching.
68 /// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
69 /// EVTs that represent all the individual underlying
70 /// non-aggregate types that comprise it.
72 /// If Offsets is non-null, it points to a vector to be filled in
73 /// with the in-memory offsets of each of the individual values.
75 void llvm::ComputeValueVTs(const TargetLowering &TLI, Type *Ty,
76 SmallVectorImpl<EVT> &ValueVTs,
77 SmallVectorImpl<uint64_t> *Offsets,
78 uint64_t StartingOffset) {
79 // Given a struct type, recursively traverse the elements.
80 if (StructType *STy = dyn_cast<StructType>(Ty)) {
81 const StructLayout *SL = TLI.getDataLayout()->getStructLayout(STy);
82 for (StructType::element_iterator EB = STy->element_begin(),
84 EE = STy->element_end();
86 ComputeValueVTs(TLI, *EI, ValueVTs, Offsets,
87 StartingOffset + SL->getElementOffset(EI - EB));
90 // Given an array type, recursively traverse the elements.
91 if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
92 Type *EltTy = ATy->getElementType();
93 uint64_t EltSize = TLI.getDataLayout()->getTypeAllocSize(EltTy);
94 for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
95 ComputeValueVTs(TLI, EltTy, ValueVTs, Offsets,
96 StartingOffset + i * EltSize);
99 // Interpret void as zero return values.
102 // Base case: we can get an EVT for this LLVM IR type.
103 ValueVTs.push_back(TLI.getValueType(Ty));
105 Offsets->push_back(StartingOffset);
108 /// ExtractTypeInfo - Returns the type info, possibly bitcast, encoded in V.
109 GlobalVariable *llvm::ExtractTypeInfo(Value *V) {
110 V = V->stripPointerCasts();
111 GlobalVariable *GV = dyn_cast<GlobalVariable>(V);
113 if (GV && GV->getName() == "llvm.eh.catch.all.value") {
114 assert(GV->hasInitializer() &&
115 "The EH catch-all value must have an initializer");
116 Value *Init = GV->getInitializer();
117 GV = dyn_cast<GlobalVariable>(Init);
118 if (!GV) V = cast<ConstantPointerNull>(Init);
121 assert((GV || isa<ConstantPointerNull>(V)) &&
122 "TypeInfo must be a global variable or NULL");
126 /// hasInlineAsmMemConstraint - Return true if the inline asm instruction being
127 /// processed uses a memory 'm' constraint.
129 llvm::hasInlineAsmMemConstraint(InlineAsm::ConstraintInfoVector &CInfos,
130 const TargetLowering &TLI) {
131 for (unsigned i = 0, e = CInfos.size(); i != e; ++i) {
132 InlineAsm::ConstraintInfo &CI = CInfos[i];
133 for (unsigned j = 0, ee = CI.Codes.size(); j != ee; ++j) {
134 TargetLowering::ConstraintType CType = TLI.getConstraintType(CI.Codes[j]);
135 if (CType == TargetLowering::C_Memory)
139 // Indirect operand accesses access memory.
147 /// getFCmpCondCode - Return the ISD condition code corresponding to
148 /// the given LLVM IR floating-point condition code. This includes
149 /// consideration of global floating-point math flags.
151 ISD::CondCode llvm::getFCmpCondCode(FCmpInst::Predicate Pred) {
153 case FCmpInst::FCMP_FALSE: return ISD::SETFALSE;
154 case FCmpInst::FCMP_OEQ: return ISD::SETOEQ;
155 case FCmpInst::FCMP_OGT: return ISD::SETOGT;
156 case FCmpInst::FCMP_OGE: return ISD::SETOGE;
157 case FCmpInst::FCMP_OLT: return ISD::SETOLT;
158 case FCmpInst::FCMP_OLE: return ISD::SETOLE;
159 case FCmpInst::FCMP_ONE: return ISD::SETONE;
160 case FCmpInst::FCMP_ORD: return ISD::SETO;
161 case FCmpInst::FCMP_UNO: return ISD::SETUO;
162 case FCmpInst::FCMP_UEQ: return ISD::SETUEQ;
163 case FCmpInst::FCMP_UGT: return ISD::SETUGT;
164 case FCmpInst::FCMP_UGE: return ISD::SETUGE;
165 case FCmpInst::FCMP_ULT: return ISD::SETULT;
166 case FCmpInst::FCMP_ULE: return ISD::SETULE;
167 case FCmpInst::FCMP_UNE: return ISD::SETUNE;
168 case FCmpInst::FCMP_TRUE: return ISD::SETTRUE;
169 default: llvm_unreachable("Invalid FCmp predicate opcode!");
173 ISD::CondCode llvm::getFCmpCodeWithoutNaN(ISD::CondCode CC) {
175 case ISD::SETOEQ: case ISD::SETUEQ: return ISD::SETEQ;
176 case ISD::SETONE: case ISD::SETUNE: return ISD::SETNE;
177 case ISD::SETOLT: case ISD::SETULT: return ISD::SETLT;
178 case ISD::SETOLE: case ISD::SETULE: return ISD::SETLE;
179 case ISD::SETOGT: case ISD::SETUGT: return ISD::SETGT;
180 case ISD::SETOGE: case ISD::SETUGE: return ISD::SETGE;
185 /// getICmpCondCode - Return the ISD condition code corresponding to
186 /// the given LLVM IR integer condition code.
188 ISD::CondCode llvm::getICmpCondCode(ICmpInst::Predicate Pred) {
190 case ICmpInst::ICMP_EQ: return ISD::SETEQ;
191 case ICmpInst::ICMP_NE: return ISD::SETNE;
192 case ICmpInst::ICMP_SLE: return ISD::SETLE;
193 case ICmpInst::ICMP_ULE: return ISD::SETULE;
194 case ICmpInst::ICMP_SGE: return ISD::SETGE;
195 case ICmpInst::ICMP_UGE: return ISD::SETUGE;
196 case ICmpInst::ICMP_SLT: return ISD::SETLT;
197 case ICmpInst::ICMP_ULT: return ISD::SETULT;
198 case ICmpInst::ICMP_SGT: return ISD::SETGT;
199 case ICmpInst::ICMP_UGT: return ISD::SETUGT;
201 llvm_unreachable("Invalid ICmp predicate opcode!");
205 static bool isNoopBitcast(Type *T1, Type *T2,
206 const TargetLoweringBase& TLI) {
207 return T1 == T2 || (T1->isPointerTy() && T2->isPointerTy()) ||
208 (isa<VectorType>(T1) && isa<VectorType>(T2) &&
209 TLI.isTypeLegal(EVT::getEVT(T1)) && TLI.isTypeLegal(EVT::getEVT(T2)));
212 /// Look through operations that will be free to find the earliest source of
215 /// @param ValLoc If V has aggegate type, we will be interested in a particular
216 /// scalar component. This records its address; the reverse of this list gives a
217 /// sequence of indices appropriate for an extractvalue to locate the important
218 /// value. This value is updated during the function and on exit will indicate
219 /// similar information for the Value returned.
221 /// @param DataBits If this function looks through truncate instructions, this
222 /// will record the smallest size attained.
223 static const Value *getNoopInput(const Value *V,
224 SmallVectorImpl<unsigned> &ValLoc,
226 const TargetLoweringBase &TLI) {
228 // Try to look through V1; if V1 is not an instruction, it can't be looked
230 const Instruction *I = dyn_cast<Instruction>(V);
231 if (!I || I->getNumOperands() == 0) return V;
232 const Value *NoopInput = nullptr;
234 Value *Op = I->getOperand(0);
235 if (isa<BitCastInst>(I)) {
236 // Look through truly no-op bitcasts.
237 if (isNoopBitcast(Op->getType(), I->getType(), TLI))
239 } else if (isa<GetElementPtrInst>(I)) {
240 // Look through getelementptr
241 if (cast<GetElementPtrInst>(I)->hasAllZeroIndices())
243 } else if (isa<IntToPtrInst>(I)) {
244 // Look through inttoptr.
245 // Make sure this isn't a truncating or extending cast. We could
246 // support this eventually, but don't bother for now.
247 if (!isa<VectorType>(I->getType()) &&
248 TLI.getPointerTy().getSizeInBits() ==
249 cast<IntegerType>(Op->getType())->getBitWidth())
251 } else if (isa<PtrToIntInst>(I)) {
252 // Look through ptrtoint.
253 // Make sure this isn't a truncating or extending cast. We could
254 // support this eventually, but don't bother for now.
255 if (!isa<VectorType>(I->getType()) &&
256 TLI.getPointerTy().getSizeInBits() ==
257 cast<IntegerType>(I->getType())->getBitWidth())
259 } else if (isa<TruncInst>(I) &&
260 TLI.allowTruncateForTailCall(Op->getType(), I->getType())) {
261 DataBits = std::min(DataBits, I->getType()->getPrimitiveSizeInBits());
263 } else if (isa<CallInst>(I)) {
264 // Look through call (skipping callee)
265 for (User::const_op_iterator i = I->op_begin(), e = I->op_end() - 1;
267 unsigned attrInd = i - I->op_begin() + 1;
268 if (cast<CallInst>(I)->paramHasAttr(attrInd, Attribute::Returned) &&
269 isNoopBitcast((*i)->getType(), I->getType(), TLI)) {
274 } else if (isa<InvokeInst>(I)) {
275 // Look through invoke (skipping BB, BB, Callee)
276 for (User::const_op_iterator i = I->op_begin(), e = I->op_end() - 3;
278 unsigned attrInd = i - I->op_begin() + 1;
279 if (cast<InvokeInst>(I)->paramHasAttr(attrInd, Attribute::Returned) &&
280 isNoopBitcast((*i)->getType(), I->getType(), TLI)) {
285 } else if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(V)) {
286 // Value may come from either the aggregate or the scalar
287 ArrayRef<unsigned> InsertLoc = IVI->getIndices();
288 if (std::equal(InsertLoc.rbegin(), InsertLoc.rend(),
290 // The type being inserted is a nested sub-type of the aggregate; we
291 // have to remove those initial indices to get the location we're
292 // interested in for the operand.
293 ValLoc.resize(ValLoc.size() - InsertLoc.size());
294 NoopInput = IVI->getInsertedValueOperand();
296 // The struct we're inserting into has the value we're interested in, no
297 // change of address.
300 } else if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(V)) {
301 // The part we're interested in will inevitably be some sub-section of the
302 // previous aggregate. Combine the two paths to obtain the true address of
304 ArrayRef<unsigned> ExtractLoc = EVI->getIndices();
305 std::copy(ExtractLoc.rbegin(), ExtractLoc.rend(),
306 std::back_inserter(ValLoc));
309 // Terminate if we couldn't find anything to look through.
317 /// Return true if this scalar return value only has bits discarded on its path
318 /// from the "tail call" to the "ret". This includes the obvious noop
319 /// instructions handled by getNoopInput above as well as free truncations (or
320 /// extensions prior to the call).
321 static bool slotOnlyDiscardsData(const Value *RetVal, const Value *CallVal,
322 SmallVectorImpl<unsigned> &RetIndices,
323 SmallVectorImpl<unsigned> &CallIndices,
324 bool AllowDifferingSizes,
325 const TargetLoweringBase &TLI) {
327 // Trace the sub-value needed by the return value as far back up the graph as
328 // possible, in the hope that it will intersect with the value produced by the
329 // call. In the simple case with no "returned" attribute, the hope is actually
330 // that we end up back at the tail call instruction itself.
331 unsigned BitsRequired = UINT_MAX;
332 RetVal = getNoopInput(RetVal, RetIndices, BitsRequired, TLI);
334 // If this slot in the value returned is undef, it doesn't matter what the
335 // call puts there, it'll be fine.
336 if (isa<UndefValue>(RetVal))
339 // Now do a similar search up through the graph to find where the value
340 // actually returned by the "tail call" comes from. In the simple case without
341 // a "returned" attribute, the search will be blocked immediately and the loop
343 unsigned BitsProvided = UINT_MAX;
344 CallVal = getNoopInput(CallVal, CallIndices, BitsProvided, TLI);
346 // There's no hope if we can't actually trace them to (the same part of!) the
348 if (CallVal != RetVal || CallIndices != RetIndices)
351 // However, intervening truncates may have made the call non-tail. Make sure
352 // all the bits that are needed by the "ret" have been provided by the "tail
353 // call". FIXME: with sufficiently cunning bit-tracking, we could look through
355 if (BitsProvided < BitsRequired ||
356 (!AllowDifferingSizes && BitsProvided != BitsRequired))
362 /// For an aggregate type, determine whether a given index is within bounds or
364 static bool indexReallyValid(CompositeType *T, unsigned Idx) {
365 if (ArrayType *AT = dyn_cast<ArrayType>(T))
366 return Idx < AT->getNumElements();
368 return Idx < cast<StructType>(T)->getNumElements();
371 /// Move the given iterators to the next leaf type in depth first traversal.
373 /// Performs a depth-first traversal of the type as specified by its arguments,
374 /// stopping at the next leaf node (which may be a legitimate scalar type or an
375 /// empty struct or array).
377 /// @param SubTypes List of the partial components making up the type from
378 /// outermost to innermost non-empty aggregate. The element currently
379 /// represented is SubTypes.back()->getTypeAtIndex(Path.back() - 1).
381 /// @param Path Set of extractvalue indices leading from the outermost type
382 /// (SubTypes[0]) to the leaf node currently represented.
384 /// @returns true if a new type was found, false otherwise. Calling this
385 /// function again on a finished iterator will repeatedly return
386 /// false. SubTypes.back()->getTypeAtIndex(Path.back()) is either an empty
387 /// aggregate or a non-aggregate
388 static bool advanceToNextLeafType(SmallVectorImpl<CompositeType *> &SubTypes,
389 SmallVectorImpl<unsigned> &Path) {
390 // First march back up the tree until we can successfully increment one of the
391 // coordinates in Path.
392 while (!Path.empty() && !indexReallyValid(SubTypes.back(), Path.back() + 1)) {
397 // If we reached the top, then the iterator is done.
401 // We know there's *some* valid leaf now, so march back down the tree picking
402 // out the left-most element at each node.
404 Type *DeeperType = SubTypes.back()->getTypeAtIndex(Path.back());
405 while (DeeperType->isAggregateType()) {
406 CompositeType *CT = cast<CompositeType>(DeeperType);
407 if (!indexReallyValid(CT, 0))
410 SubTypes.push_back(CT);
413 DeeperType = CT->getTypeAtIndex(0U);
419 /// Find the first non-empty, scalar-like type in Next and setup the iterator
422 /// Assuming Next is an aggregate of some kind, this function will traverse the
423 /// tree from left to right (i.e. depth-first) looking for the first
424 /// non-aggregate type which will play a role in function return.
426 /// For example, if Next was {[0 x i64], {{}, i32, {}}, i32} then we would setup
427 /// Path as [1, 1] and SubTypes as [Next, {{}, i32, {}}] to represent the first
428 /// i32 in that type.
429 static bool firstRealType(Type *Next,
430 SmallVectorImpl<CompositeType *> &SubTypes,
431 SmallVectorImpl<unsigned> &Path) {
432 // First initialise the iterator components to the first "leaf" node
433 // (i.e. node with no valid sub-type at any index, so {} does count as a leaf
434 // despite nominally being an aggregate).
435 while (Next->isAggregateType() &&
436 indexReallyValid(cast<CompositeType>(Next), 0)) {
437 SubTypes.push_back(cast<CompositeType>(Next));
439 Next = cast<CompositeType>(Next)->getTypeAtIndex(0U);
442 // If there's no Path now, Next was originally scalar already (or empty
443 // leaf). We're done.
447 // Otherwise, use normal iteration to keep looking through the tree until we
448 // find a non-aggregate type.
449 while (SubTypes.back()->getTypeAtIndex(Path.back())->isAggregateType()) {
450 if (!advanceToNextLeafType(SubTypes, Path))
457 /// Set the iterator data-structures to the next non-empty, non-aggregate
459 static bool nextRealType(SmallVectorImpl<CompositeType *> &SubTypes,
460 SmallVectorImpl<unsigned> &Path) {
462 if (!advanceToNextLeafType(SubTypes, Path))
465 assert(!Path.empty() && "found a leaf but didn't set the path?");
466 } while (SubTypes.back()->getTypeAtIndex(Path.back())->isAggregateType());
472 /// Test if the given instruction is in a position to be optimized
473 /// with a tail-call. This roughly means that it's in a block with
474 /// a return and there's nothing that needs to be scheduled
475 /// between it and the return.
477 /// This function only tests target-independent requirements.
478 bool llvm::isInTailCallPosition(ImmutableCallSite CS, const SelectionDAG &DAG) {
479 const Instruction *I = CS.getInstruction();
480 const BasicBlock *ExitBB = I->getParent();
481 const TerminatorInst *Term = ExitBB->getTerminator();
482 const ReturnInst *Ret = dyn_cast<ReturnInst>(Term);
484 // The block must end in a return statement or unreachable.
486 // FIXME: Decline tailcall if it's not guaranteed and if the block ends in
487 // an unreachable, for now. The way tailcall optimization is currently
488 // implemented means it will add an epilogue followed by a jump. That is
489 // not profitable. Also, if the callee is a special function (e.g.
490 // longjmp on x86), it can end up causing miscompilation that has not
491 // been fully understood.
493 (!DAG.getTarget().Options.GuaranteedTailCallOpt ||
494 !isa<UnreachableInst>(Term)))
497 // If I will have a chain, make sure no other instruction that will have a
498 // chain interposes between I and the return.
499 if (I->mayHaveSideEffects() || I->mayReadFromMemory() ||
500 !isSafeToSpeculativelyExecute(I))
501 for (BasicBlock::const_iterator BBI = std::prev(ExitBB->end(), 2);; --BBI) {
504 // Debug info intrinsics do not get in the way of tail call optimization.
505 if (isa<DbgInfoIntrinsic>(BBI))
507 if (BBI->mayHaveSideEffects() || BBI->mayReadFromMemory() ||
508 !isSafeToSpeculativelyExecute(BBI))
512 return returnTypeIsEligibleForTailCall(ExitBB->getParent(), I, Ret,
513 *DAG.getTarget().getTargetLowering());
516 bool llvm::returnTypeIsEligibleForTailCall(const Function *F,
517 const Instruction *I,
518 const ReturnInst *Ret,
519 const TargetLoweringBase &TLI) {
520 // If the block ends with a void return or unreachable, it doesn't matter
521 // what the call's return type is.
522 if (!Ret || Ret->getNumOperands() == 0) return true;
524 // If the return value is undef, it doesn't matter what the call's
526 if (isa<UndefValue>(Ret->getOperand(0))) return true;
528 // Make sure the attributes attached to each return are compatible.
529 AttrBuilder CallerAttrs(F->getAttributes(),
530 AttributeSet::ReturnIndex);
531 AttrBuilder CalleeAttrs(cast<CallInst>(I)->getAttributes(),
532 AttributeSet::ReturnIndex);
534 // Noalias is completely benign as far as calling convention goes, it
535 // shouldn't affect whether the call is a tail call.
536 CallerAttrs = CallerAttrs.removeAttribute(Attribute::NoAlias);
537 CalleeAttrs = CalleeAttrs.removeAttribute(Attribute::NoAlias);
539 bool AllowDifferingSizes = true;
540 if (CallerAttrs.contains(Attribute::ZExt)) {
541 if (!CalleeAttrs.contains(Attribute::ZExt))
544 AllowDifferingSizes = false;
545 CallerAttrs.removeAttribute(Attribute::ZExt);
546 CalleeAttrs.removeAttribute(Attribute::ZExt);
547 } else if (CallerAttrs.contains(Attribute::SExt)) {
548 if (!CalleeAttrs.contains(Attribute::SExt))
551 AllowDifferingSizes = false;
552 CallerAttrs.removeAttribute(Attribute::SExt);
553 CalleeAttrs.removeAttribute(Attribute::SExt);
556 // If they're still different, there's some facet we don't understand
557 // (currently only "inreg", but in future who knows). It may be OK but the
558 // only safe option is to reject the tail call.
559 if (CallerAttrs != CalleeAttrs)
562 const Value *RetVal = Ret->getOperand(0), *CallVal = I;
563 SmallVector<unsigned, 4> RetPath, CallPath;
564 SmallVector<CompositeType *, 4> RetSubTypes, CallSubTypes;
566 bool RetEmpty = !firstRealType(RetVal->getType(), RetSubTypes, RetPath);
567 bool CallEmpty = !firstRealType(CallVal->getType(), CallSubTypes, CallPath);
569 // Nothing's actually returned, it doesn't matter what the callee put there
570 // it's a valid tail call.
574 // Iterate pairwise through each of the value types making up the tail call
575 // and the corresponding return. For each one we want to know whether it's
576 // essentially going directly from the tail call to the ret, via operations
577 // that end up not generating any code.
579 // We allow a certain amount of covariance here. For example it's permitted
580 // for the tail call to define more bits than the ret actually cares about
581 // (e.g. via a truncate).
584 // We've exhausted the values produced by the tail call instruction, the
585 // rest are essentially undef. The type doesn't really matter, but we need
587 Type *SlotType = RetSubTypes.back()->getTypeAtIndex(RetPath.back());
588 CallVal = UndefValue::get(SlotType);
591 // The manipulations performed when we're looking through an insertvalue or
592 // an extractvalue would happen at the front of the RetPath list, so since
593 // we have to copy it anyway it's more efficient to create a reversed copy.
595 SmallVector<unsigned, 4> TmpRetPath, TmpCallPath;
596 copy(RetPath.rbegin(), RetPath.rend(), std::back_inserter(TmpRetPath));
597 copy(CallPath.rbegin(), CallPath.rend(), std::back_inserter(TmpCallPath));
599 // Finally, we can check whether the value produced by the tail call at this
600 // index is compatible with the value we return.
601 if (!slotOnlyDiscardsData(RetVal, CallVal, TmpRetPath, TmpCallPath,
602 AllowDifferingSizes, TLI))
605 CallEmpty = !nextRealType(CallSubTypes, CallPath);
606 } while(nextRealType(RetSubTypes, RetPath));