1 //==-- CGFunctionInfo.h - Representation of function argument/return types -==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Defines CGFunctionInfo and associated types used in representing the
10 // LLVM source types and ABI-coerced types for function arguments and
11 // return values.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_CODEGEN_CGFUNCTIONINFO_H
16 #define LLVM_CLANG_CODEGEN_CGFUNCTIONINFO_H
17 
18 #include "clang/AST/CanonicalType.h"
19 #include "clang/AST/CharUnits.h"
20 #include "clang/AST/Decl.h"
21 #include "clang/AST/Type.h"
22 #include "llvm/IR/DerivedTypes.h"
23 #include "llvm/ADT/FoldingSet.h"
24 #include "llvm/Support/TrailingObjects.h"
25 #include <cassert>
26 
27 namespace clang {
28 namespace CodeGen {
29 
30 /// ABIArgInfo - Helper class to encapsulate information about how a
31 /// specific C type should be passed to or returned from a function.
32 class ABIArgInfo {
33 public:
34   enum Kind : uint8_t {
35     /// Direct - Pass the argument directly using the normal converted LLVM
36     /// type, or by coercing to another specified type stored in
37     /// 'CoerceToType').  If an offset is specified (in UIntData), then the
38     /// argument passed is offset by some number of bytes in the memory
39     /// representation. A dummy argument is emitted before the real argument
40     /// if the specified type stored in "PaddingType" is not zero.
41     Direct,
42 
43     /// Extend - Valid only for integer argument types. Same as 'direct'
44     /// but also emit a zero/sign extension attribute.
45     Extend,
46 
47     /// Indirect - Pass the argument indirectly via a hidden pointer with the
48     /// specified alignment (0 indicates default alignment) and address space.
49     Indirect,
50 
51     /// IndirectAliased - Similar to Indirect, but the pointer may be to an
52     /// object that is otherwise referenced.  The object is known to not be
53     /// modified through any other references for the duration of the call, and
54     /// the callee must not itself modify the object.  Because C allows
55     /// parameter variables to be modified and guarantees that they have unique
56     /// addresses, the callee must defensively copy the object into a local
57     /// variable if it might be modified or its address might be compared.
58     /// Since those are uncommon, in principle this convention allows programs
59     /// to avoid copies in more situations.  However, it may introduce *extra*
60     /// copies if the callee fails to prove that a copy is unnecessary and the
61     /// caller naturally produces an unaliased object for the argument.
62     IndirectAliased,
63 
64     /// Ignore - Ignore the argument (treat as void). Useful for void and
65     /// empty structs.
66     Ignore,
67 
68     /// Expand - Only valid for aggregate argument types. The structure should
69     /// be expanded into consecutive arguments for its constituent fields.
70     /// Currently expand is only allowed on structures whose fields
71     /// are all scalar types or are themselves expandable types.
72     Expand,
73 
74     /// CoerceAndExpand - Only valid for aggregate argument types. The
75     /// structure should be expanded into consecutive arguments corresponding
76     /// to the non-array elements of the type stored in CoerceToType.
77     /// Array elements in the type are assumed to be padding and skipped.
78     CoerceAndExpand,
79 
80     /// InAlloca - Pass the argument directly using the LLVM inalloca attribute.
81     /// This is similar to indirect with byval, except it only applies to
82     /// arguments stored in memory and forbids any implicit copies.  When
83     /// applied to a return type, it means the value is returned indirectly via
84     /// an implicit sret parameter stored in the argument struct.
85     InAlloca,
86     KindFirst = Direct,
87     KindLast = InAlloca
88   };
89 
90 private:
91   llvm::Type *TypeData; // canHaveCoerceToType()
92   union {
93     llvm::Type *PaddingType; // canHavePaddingType()
94     llvm::Type *UnpaddedCoerceAndExpandType; // isCoerceAndExpand()
95   };
96   struct DirectAttrInfo {
97     unsigned Offset;
98     unsigned Align;
99   };
100   struct IndirectAttrInfo {
101     unsigned Align;
102     unsigned AddrSpace;
103   };
104   union {
105     DirectAttrInfo DirectAttr;     // isDirect() || isExtend()
106     IndirectAttrInfo IndirectAttr; // isIndirect()
107     unsigned AllocaFieldIndex; // isInAlloca()
108   };
109   Kind TheKind;
110   bool PaddingInReg : 1;
111   bool InAllocaSRet : 1;    // isInAlloca()
112   bool InAllocaIndirect : 1;// isInAlloca()
113   bool IndirectByVal : 1;   // isIndirect()
114   bool IndirectRealign : 1; // isIndirect()
115   bool SRetAfterThis : 1;   // isIndirect()
116   bool InReg : 1;           // isDirect() || isExtend() || isIndirect()
117   bool CanBeFlattened: 1;   // isDirect()
118   bool SignExt : 1;         // isExtend()
119 
120   bool canHavePaddingType() const {
121     return isDirect() || isExtend() || isIndirect() || isIndirectAliased() ||
122            isExpand();
123   }
124   void setPaddingType(llvm::Type *T) {
125     assert(canHavePaddingType());
126     PaddingType = T;
127   }
128 
129   void setUnpaddedCoerceToType(llvm::Type *T) {
130     assert(isCoerceAndExpand());
131     UnpaddedCoerceAndExpandType = T;
132   }
133 
134 public:
135   ABIArgInfo(Kind K = Direct)
136       : TypeData(nullptr), PaddingType(nullptr), DirectAttr{0, 0}, TheKind(K),
137         PaddingInReg(false), InAllocaSRet(false),
138         InAllocaIndirect(false), IndirectByVal(false), IndirectRealign(false),
139         SRetAfterThis(false), InReg(false), CanBeFlattened(false),
140         SignExt(false) {}
141 
142   static ABIArgInfo getDirect(llvm::Type *T = nullptr, unsigned Offset = 0,
143                               llvm::Type *Padding = nullptr,
144                               bool CanBeFlattened = true, unsigned Align = 0) {
145     auto AI = ABIArgInfo(Direct);
146     AI.setCoerceToType(T);
147     AI.setPaddingType(Padding);
148     AI.setDirectOffset(Offset);
149     AI.setDirectAlign(Align);
150     AI.setCanBeFlattened(CanBeFlattened);
151     return AI;
152   }
153   static ABIArgInfo getDirectInReg(llvm::Type *T = nullptr) {
154     auto AI = getDirect(T);
155     AI.setInReg(true);
156     return AI;
157   }
158 
159   static ABIArgInfo getSignExtend(QualType Ty, llvm::Type *T = nullptr) {
160     assert(Ty->isIntegralOrEnumerationType() && "Unexpected QualType");
161     auto AI = ABIArgInfo(Extend);
162     AI.setCoerceToType(T);
163     AI.setPaddingType(nullptr);
164     AI.setDirectOffset(0);
165     AI.setDirectAlign(0);
166     AI.setSignExt(true);
167     return AI;
168   }
169 
170   static ABIArgInfo getZeroExtend(QualType Ty, llvm::Type *T = nullptr) {
171     assert(Ty->isIntegralOrEnumerationType() && "Unexpected QualType");
172     auto AI = ABIArgInfo(Extend);
173     AI.setCoerceToType(T);
174     AI.setPaddingType(nullptr);
175     AI.setDirectOffset(0);
176     AI.setDirectAlign(0);
177     AI.setSignExt(false);
178     return AI;
179   }
180 
181   // ABIArgInfo will record the argument as being extended based on the sign
182   // of its type.
183   static ABIArgInfo getExtend(QualType Ty, llvm::Type *T = nullptr) {
184     assert(Ty->isIntegralOrEnumerationType() && "Unexpected QualType");
185     if (Ty->hasSignedIntegerRepresentation())
186       return getSignExtend(Ty, T);
187     return getZeroExtend(Ty, T);
188   }
189 
190   static ABIArgInfo getExtendInReg(QualType Ty, llvm::Type *T = nullptr) {
191     auto AI = getExtend(Ty, T);
192     AI.setInReg(true);
193     return AI;
194   }
195   static ABIArgInfo getIgnore() {
196     return ABIArgInfo(Ignore);
197   }
198   static ABIArgInfo getIndirect(CharUnits Alignment, bool ByVal = true,
199                                 bool Realign = false,
200                                 llvm::Type *Padding = nullptr) {
201     auto AI = ABIArgInfo(Indirect);
202     AI.setIndirectAlign(Alignment);
203     AI.setIndirectByVal(ByVal);
204     AI.setIndirectRealign(Realign);
205     AI.setSRetAfterThis(false);
206     AI.setPaddingType(Padding);
207     return AI;
208   }
209 
210   /// Pass this in memory using the IR byref attribute.
211   static ABIArgInfo getIndirectAliased(CharUnits Alignment, unsigned AddrSpace,
212                                        bool Realign = false,
213                                        llvm::Type *Padding = nullptr) {
214     auto AI = ABIArgInfo(IndirectAliased);
215     AI.setIndirectAlign(Alignment);
216     AI.setIndirectRealign(Realign);
217     AI.setPaddingType(Padding);
218     AI.setIndirectAddrSpace(AddrSpace);
219     return AI;
220   }
221 
222   static ABIArgInfo getIndirectInReg(CharUnits Alignment, bool ByVal = true,
223                                      bool Realign = false) {
224     auto AI = getIndirect(Alignment, ByVal, Realign);
225     AI.setInReg(true);
226     return AI;
227   }
228   static ABIArgInfo getInAlloca(unsigned FieldIndex, bool Indirect = false) {
229     auto AI = ABIArgInfo(InAlloca);
230     AI.setInAllocaFieldIndex(FieldIndex);
231     AI.setInAllocaIndirect(Indirect);
232     return AI;
233   }
234   static ABIArgInfo getExpand() {
235     auto AI = ABIArgInfo(Expand);
236     AI.setPaddingType(nullptr);
237     return AI;
238   }
239   static ABIArgInfo getExpandWithPadding(bool PaddingInReg,
240                                          llvm::Type *Padding) {
241     auto AI = getExpand();
242     AI.setPaddingInReg(PaddingInReg);
243     AI.setPaddingType(Padding);
244     return AI;
245   }
246 
247   /// \param unpaddedCoerceToType The coerce-to type with padding elements
248   ///   removed, canonicalized to a single element if it would otherwise
249   ///   have exactly one element.
250   static ABIArgInfo getCoerceAndExpand(llvm::StructType *coerceToType,
251                                        llvm::Type *unpaddedCoerceToType) {
252 #ifndef NDEBUG
253     // Check that unpaddedCoerceToType has roughly the right shape.
254 
255     // Assert that we only have a struct type if there are multiple elements.
256     auto unpaddedStruct = dyn_cast<llvm::StructType>(unpaddedCoerceToType);
257     assert(!unpaddedStruct || unpaddedStruct->getNumElements() != 1);
258 
259     // Assert that all the non-padding elements have a corresponding element
260     // in the unpadded type.
261     unsigned unpaddedIndex = 0;
262     for (auto eltType : coerceToType->elements()) {
263       if (isPaddingForCoerceAndExpand(eltType)) continue;
264       if (unpaddedStruct) {
265         assert(unpaddedStruct->getElementType(unpaddedIndex) == eltType);
266       } else {
267         assert(unpaddedIndex == 0 && unpaddedCoerceToType == eltType);
268       }
269       unpaddedIndex++;
270     }
271 
272     // Assert that there aren't extra elements in the unpadded type.
273     if (unpaddedStruct) {
274       assert(unpaddedStruct->getNumElements() == unpaddedIndex);
275     } else {
276       assert(unpaddedIndex == 1);
277     }
278 #endif
279 
280     auto AI = ABIArgInfo(CoerceAndExpand);
281     AI.setCoerceToType(coerceToType);
282     AI.setUnpaddedCoerceToType(unpaddedCoerceToType);
283     return AI;
284   }
285 
286   static bool isPaddingForCoerceAndExpand(llvm::Type *eltType) {
287     if (eltType->isArrayTy()) {
288       assert(eltType->getArrayElementType()->isIntegerTy(8));
289       return true;
290     } else {
291       return false;
292     }
293   }
294 
295   Kind getKind() const { return TheKind; }
296   bool isDirect() const { return TheKind == Direct; }
297   bool isInAlloca() const { return TheKind == InAlloca; }
298   bool isExtend() const { return TheKind == Extend; }
299   bool isIgnore() const { return TheKind == Ignore; }
300   bool isIndirect() const { return TheKind == Indirect; }
301   bool isIndirectAliased() const { return TheKind == IndirectAliased; }
302   bool isExpand() const { return TheKind == Expand; }
303   bool isCoerceAndExpand() const { return TheKind == CoerceAndExpand; }
304 
305   bool canHaveCoerceToType() const {
306     return isDirect() || isExtend() || isCoerceAndExpand();
307   }
308 
309   // Direct/Extend accessors
310   unsigned getDirectOffset() const {
311     assert((isDirect() || isExtend()) && "Not a direct or extend kind");
312     return DirectAttr.Offset;
313   }
314   void setDirectOffset(unsigned Offset) {
315     assert((isDirect() || isExtend()) && "Not a direct or extend kind");
316     DirectAttr.Offset = Offset;
317   }
318 
319   unsigned getDirectAlign() const {
320     assert((isDirect() || isExtend()) && "Not a direct or extend kind");
321     return DirectAttr.Align;
322   }
323   void setDirectAlign(unsigned Align) {
324     assert((isDirect() || isExtend()) && "Not a direct or extend kind");
325     DirectAttr.Align = Align;
326   }
327 
328   bool isSignExt() const {
329     assert(isExtend() && "Invalid kind!");
330     return SignExt;
331   }
332   void setSignExt(bool SExt) {
333     assert(isExtend() && "Invalid kind!");
334     SignExt = SExt;
335   }
336 
337   llvm::Type *getPaddingType() const {
338     return (canHavePaddingType() ? PaddingType : nullptr);
339   }
340 
341   bool getPaddingInReg() const {
342     return PaddingInReg;
343   }
344   void setPaddingInReg(bool PIR) {
345     PaddingInReg = PIR;
346   }
347 
348   llvm::Type *getCoerceToType() const {
349     assert(canHaveCoerceToType() && "Invalid kind!");
350     return TypeData;
351   }
352 
353   void setCoerceToType(llvm::Type *T) {
354     assert(canHaveCoerceToType() && "Invalid kind!");
355     TypeData = T;
356   }
357 
358   llvm::StructType *getCoerceAndExpandType() const {
359     assert(isCoerceAndExpand());
360     return cast<llvm::StructType>(TypeData);
361   }
362 
363   llvm::Type *getUnpaddedCoerceAndExpandType() const {
364     assert(isCoerceAndExpand());
365     return UnpaddedCoerceAndExpandType;
366   }
367 
368   ArrayRef<llvm::Type *>getCoerceAndExpandTypeSequence() const {
369     assert(isCoerceAndExpand());
370     if (auto structTy =
371           dyn_cast<llvm::StructType>(UnpaddedCoerceAndExpandType)) {
372       return structTy->elements();
373     } else {
374       return llvm::ArrayRef(&UnpaddedCoerceAndExpandType, 1);
375     }
376   }
377 
378   bool getInReg() const {
379     assert((isDirect() || isExtend() || isIndirect()) && "Invalid kind!");
380     return InReg;
381   }
382 
383   void setInReg(bool IR) {
384     assert((isDirect() || isExtend() || isIndirect()) && "Invalid kind!");
385     InReg = IR;
386   }
387 
388   // Indirect accessors
389   CharUnits getIndirectAlign() const {
390     assert((isIndirect() || isIndirectAliased()) && "Invalid kind!");
391     return CharUnits::fromQuantity(IndirectAttr.Align);
392   }
393   void setIndirectAlign(CharUnits IA) {
394     assert((isIndirect() || isIndirectAliased()) && "Invalid kind!");
395     IndirectAttr.Align = IA.getQuantity();
396   }
397 
398   bool getIndirectByVal() const {
399     assert(isIndirect() && "Invalid kind!");
400     return IndirectByVal;
401   }
402   void setIndirectByVal(bool IBV) {
403     assert(isIndirect() && "Invalid kind!");
404     IndirectByVal = IBV;
405   }
406 
407   unsigned getIndirectAddrSpace() const {
408     assert(isIndirectAliased() && "Invalid kind!");
409     return IndirectAttr.AddrSpace;
410   }
411 
412   void setIndirectAddrSpace(unsigned AddrSpace) {
413     assert(isIndirectAliased() && "Invalid kind!");
414     IndirectAttr.AddrSpace = AddrSpace;
415   }
416 
417   bool getIndirectRealign() const {
418     assert((isIndirect() || isIndirectAliased()) && "Invalid kind!");
419     return IndirectRealign;
420   }
421   void setIndirectRealign(bool IR) {
422     assert((isIndirect() || isIndirectAliased()) && "Invalid kind!");
423     IndirectRealign = IR;
424   }
425 
426   bool isSRetAfterThis() const {
427     assert(isIndirect() && "Invalid kind!");
428     return SRetAfterThis;
429   }
430   void setSRetAfterThis(bool AfterThis) {
431     assert(isIndirect() && "Invalid kind!");
432     SRetAfterThis = AfterThis;
433   }
434 
435   unsigned getInAllocaFieldIndex() const {
436     assert(isInAlloca() && "Invalid kind!");
437     return AllocaFieldIndex;
438   }
439   void setInAllocaFieldIndex(unsigned FieldIndex) {
440     assert(isInAlloca() && "Invalid kind!");
441     AllocaFieldIndex = FieldIndex;
442   }
443 
444   unsigned getInAllocaIndirect() const {
445     assert(isInAlloca() && "Invalid kind!");
446     return InAllocaIndirect;
447   }
448   void setInAllocaIndirect(bool Indirect) {
449     assert(isInAlloca() && "Invalid kind!");
450     InAllocaIndirect = Indirect;
451   }
452 
453   /// Return true if this field of an inalloca struct should be returned
454   /// to implement a struct return calling convention.
455   bool getInAllocaSRet() const {
456     assert(isInAlloca() && "Invalid kind!");
457     return InAllocaSRet;
458   }
459 
460   void setInAllocaSRet(bool SRet) {
461     assert(isInAlloca() && "Invalid kind!");
462     InAllocaSRet = SRet;
463   }
464 
465   bool getCanBeFlattened() const {
466     assert(isDirect() && "Invalid kind!");
467     return CanBeFlattened;
468   }
469 
470   void setCanBeFlattened(bool Flatten) {
471     assert(isDirect() && "Invalid kind!");
472     CanBeFlattened = Flatten;
473   }
474 
475   void dump() const;
476 };
477 
478 /// A class for recording the number of arguments that a function
479 /// signature requires.
480 class RequiredArgs {
481   /// The number of required arguments, or ~0 if the signature does
482   /// not permit optional arguments.
483   unsigned NumRequired;
484 public:
485   enum All_t { All };
486 
487   RequiredArgs(All_t _) : NumRequired(~0U) {}
488   explicit RequiredArgs(unsigned n) : NumRequired(n) {
489     assert(n != ~0U);
490   }
491 
492   /// Compute the arguments required by the given formal prototype,
493   /// given that there may be some additional, non-formal arguments
494   /// in play.
495   ///
496   /// If FD is not null, this will consider pass_object_size params in FD.
497   static RequiredArgs forPrototypePlus(const FunctionProtoType *prototype,
498                                        unsigned additional) {
499     if (!prototype->isVariadic()) return All;
500 
501     if (prototype->hasExtParameterInfos())
502       additional += llvm::count_if(
503           prototype->getExtParameterInfos(),
504           [](const FunctionProtoType::ExtParameterInfo &ExtInfo) {
505             return ExtInfo.hasPassObjectSize();
506           });
507 
508     return RequiredArgs(prototype->getNumParams() + additional);
509   }
510 
511   static RequiredArgs forPrototypePlus(CanQual<FunctionProtoType> prototype,
512                                        unsigned additional) {
513     return forPrototypePlus(prototype.getTypePtr(), additional);
514   }
515 
516   static RequiredArgs forPrototype(const FunctionProtoType *prototype) {
517     return forPrototypePlus(prototype, 0);
518   }
519 
520   static RequiredArgs forPrototype(CanQual<FunctionProtoType> prototype) {
521     return forPrototypePlus(prototype.getTypePtr(), 0);
522   }
523 
524   bool allowsOptionalArgs() const { return NumRequired != ~0U; }
525   unsigned getNumRequiredArgs() const {
526     assert(allowsOptionalArgs());
527     return NumRequired;
528   }
529 
530   /// Return true if the argument at a given index is required.
531   bool isRequiredArg(unsigned argIdx) const {
532     return argIdx == ~0U || argIdx < NumRequired;
533   }
534 
535   unsigned getOpaqueData() const { return NumRequired; }
536   static RequiredArgs getFromOpaqueData(unsigned value) {
537     if (value == ~0U) return All;
538     return RequiredArgs(value);
539   }
540 };
541 
542 // Implementation detail of CGFunctionInfo, factored out so it can be named
543 // in the TrailingObjects base class of CGFunctionInfo.
544 struct CGFunctionInfoArgInfo {
545   CanQualType type;
546   ABIArgInfo info;
547 };
548 
549 /// CGFunctionInfo - Class to encapsulate the information about a
550 /// function definition.
551 class CGFunctionInfo final
552     : public llvm::FoldingSetNode,
553       private llvm::TrailingObjects<CGFunctionInfo, CGFunctionInfoArgInfo,
554                                     FunctionProtoType::ExtParameterInfo> {
555   typedef CGFunctionInfoArgInfo ArgInfo;
556   typedef FunctionProtoType::ExtParameterInfo ExtParameterInfo;
557 
558   /// The LLVM::CallingConv to use for this function (as specified by the
559   /// user).
560   unsigned CallingConvention : 8;
561 
562   /// The LLVM::CallingConv to actually use for this function, which may
563   /// depend on the ABI.
564   unsigned EffectiveCallingConvention : 8;
565 
566   /// The clang::CallingConv that this was originally created with.
567   unsigned ASTCallingConvention : 6;
568 
569   /// Whether this is an instance method.
570   unsigned InstanceMethod : 1;
571 
572   /// Whether this is a chain call.
573   unsigned ChainCall : 1;
574 
575   /// Whether this function is called by forwarding arguments.
576   /// This doesn't support inalloca or varargs.
577   unsigned DelegateCall : 1;
578 
579   /// Whether this function is a CMSE nonsecure call
580   unsigned CmseNSCall : 1;
581 
582   /// Whether this function is noreturn.
583   unsigned NoReturn : 1;
584 
585   /// Whether this function is returns-retained.
586   unsigned ReturnsRetained : 1;
587 
588   /// Whether this function saved caller registers.
589   unsigned NoCallerSavedRegs : 1;
590 
591   /// How many arguments to pass inreg.
592   unsigned HasRegParm : 1;
593   unsigned RegParm : 3;
594 
595   /// Whether this function has nocf_check attribute.
596   unsigned NoCfCheck : 1;
597 
598   /// Log 2 of the maximum vector width.
599   unsigned MaxVectorWidth : 4;
600 
601   RequiredArgs Required;
602 
603   /// The struct representing all arguments passed in memory.  Only used when
604   /// passing non-trivial types with inalloca.  Not part of the profile.
605   llvm::StructType *ArgStruct;
606   unsigned ArgStructAlign : 31;
607   unsigned HasExtParameterInfos : 1;
608 
609   unsigned NumArgs;
610 
611   ArgInfo *getArgsBuffer() {
612     return getTrailingObjects<ArgInfo>();
613   }
614   const ArgInfo *getArgsBuffer() const {
615     return getTrailingObjects<ArgInfo>();
616   }
617 
618   ExtParameterInfo *getExtParameterInfosBuffer() {
619     return getTrailingObjects<ExtParameterInfo>();
620   }
621   const ExtParameterInfo *getExtParameterInfosBuffer() const{
622     return getTrailingObjects<ExtParameterInfo>();
623   }
624 
625   CGFunctionInfo() : Required(RequiredArgs::All) {}
626 
627 public:
628   static CGFunctionInfo *
629   create(unsigned llvmCC, bool instanceMethod, bool chainCall,
630          bool delegateCall, const FunctionType::ExtInfo &extInfo,
631          ArrayRef<ExtParameterInfo> paramInfos, CanQualType resultType,
632          ArrayRef<CanQualType> argTypes, RequiredArgs required);
633   void operator delete(void *p) { ::operator delete(p); }
634 
635   // Friending class TrailingObjects is apparently not good enough for MSVC,
636   // so these have to be public.
637   friend class TrailingObjects;
638   size_t numTrailingObjects(OverloadToken<ArgInfo>) const {
639     return NumArgs + 1;
640   }
641   size_t numTrailingObjects(OverloadToken<ExtParameterInfo>) const {
642     return (HasExtParameterInfos ? NumArgs : 0);
643   }
644 
645   typedef const ArgInfo *const_arg_iterator;
646   typedef ArgInfo *arg_iterator;
647 
648   MutableArrayRef<ArgInfo> arguments() {
649     return MutableArrayRef<ArgInfo>(arg_begin(), NumArgs);
650   }
651   ArrayRef<ArgInfo> arguments() const {
652     return ArrayRef<ArgInfo>(arg_begin(), NumArgs);
653   }
654 
655   const_arg_iterator arg_begin() const { return getArgsBuffer() + 1; }
656   const_arg_iterator arg_end() const { return getArgsBuffer() + 1 + NumArgs; }
657   arg_iterator arg_begin() { return getArgsBuffer() + 1; }
658   arg_iterator arg_end() { return getArgsBuffer() + 1 + NumArgs; }
659 
660   unsigned  arg_size() const { return NumArgs; }
661 
662   bool isVariadic() const { return Required.allowsOptionalArgs(); }
663   RequiredArgs getRequiredArgs() const { return Required; }
664   unsigned getNumRequiredArgs() const {
665     return isVariadic() ? getRequiredArgs().getNumRequiredArgs() : arg_size();
666   }
667 
668   bool isInstanceMethod() const { return InstanceMethod; }
669 
670   bool isChainCall() const { return ChainCall; }
671 
672   bool isDelegateCall() const { return DelegateCall; }
673 
674   bool isCmseNSCall() const { return CmseNSCall; }
675 
676   bool isNoReturn() const { return NoReturn; }
677 
678   /// In ARC, whether this function retains its return value.  This
679   /// is not always reliable for call sites.
680   bool isReturnsRetained() const { return ReturnsRetained; }
681 
682   /// Whether this function no longer saves caller registers.
683   bool isNoCallerSavedRegs() const { return NoCallerSavedRegs; }
684 
685   /// Whether this function has nocf_check attribute.
686   bool isNoCfCheck() const { return NoCfCheck; }
687 
688   /// getASTCallingConvention() - Return the AST-specified calling
689   /// convention.
690   CallingConv getASTCallingConvention() const {
691     return CallingConv(ASTCallingConvention);
692   }
693 
694   /// getCallingConvention - Return the user specified calling
695   /// convention, which has been translated into an LLVM CC.
696   unsigned getCallingConvention() const { return CallingConvention; }
697 
698   /// getEffectiveCallingConvention - Return the actual calling convention to
699   /// use, which may depend on the ABI.
700   unsigned getEffectiveCallingConvention() const {
701     return EffectiveCallingConvention;
702   }
703   void setEffectiveCallingConvention(unsigned Value) {
704     EffectiveCallingConvention = Value;
705   }
706 
707   bool getHasRegParm() const { return HasRegParm; }
708   unsigned getRegParm() const { return RegParm; }
709 
710   FunctionType::ExtInfo getExtInfo() const {
711     return FunctionType::ExtInfo(isNoReturn(), getHasRegParm(), getRegParm(),
712                                  getASTCallingConvention(), isReturnsRetained(),
713                                  isNoCallerSavedRegs(), isNoCfCheck(),
714                                  isCmseNSCall());
715   }
716 
717   CanQualType getReturnType() const { return getArgsBuffer()[0].type; }
718 
719   ABIArgInfo &getReturnInfo() { return getArgsBuffer()[0].info; }
720   const ABIArgInfo &getReturnInfo() const { return getArgsBuffer()[0].info; }
721 
722   ArrayRef<ExtParameterInfo> getExtParameterInfos() const {
723     if (!HasExtParameterInfos) return {};
724     return llvm::ArrayRef(getExtParameterInfosBuffer(), NumArgs);
725   }
726   ExtParameterInfo getExtParameterInfo(unsigned argIndex) const {
727     assert(argIndex <= NumArgs);
728     if (!HasExtParameterInfos) return ExtParameterInfo();
729     return getExtParameterInfos()[argIndex];
730   }
731 
732   /// Return true if this function uses inalloca arguments.
733   bool usesInAlloca() const { return ArgStruct; }
734 
735   /// Get the struct type used to represent all the arguments in memory.
736   llvm::StructType *getArgStruct() const { return ArgStruct; }
737   CharUnits getArgStructAlignment() const {
738     return CharUnits::fromQuantity(ArgStructAlign);
739   }
740   void setArgStruct(llvm::StructType *Ty, CharUnits Align) {
741     ArgStruct = Ty;
742     ArgStructAlign = Align.getQuantity();
743   }
744 
745   /// Return the maximum vector width in the arguments.
746   unsigned getMaxVectorWidth() const {
747     return MaxVectorWidth ? 1U << (MaxVectorWidth - 1) : 0;
748   }
749 
750   /// Set the maximum vector width in the arguments.
751   void setMaxVectorWidth(unsigned Width) {
752     assert(llvm::isPowerOf2_32(Width) && "Expected power of 2 vector");
753     MaxVectorWidth = llvm::countr_zero(Width) + 1;
754   }
755 
756   void Profile(llvm::FoldingSetNodeID &ID) {
757     ID.AddInteger(getASTCallingConvention());
758     ID.AddBoolean(InstanceMethod);
759     ID.AddBoolean(ChainCall);
760     ID.AddBoolean(DelegateCall);
761     ID.AddBoolean(NoReturn);
762     ID.AddBoolean(ReturnsRetained);
763     ID.AddBoolean(NoCallerSavedRegs);
764     ID.AddBoolean(HasRegParm);
765     ID.AddInteger(RegParm);
766     ID.AddBoolean(NoCfCheck);
767     ID.AddBoolean(CmseNSCall);
768     ID.AddInteger(Required.getOpaqueData());
769     ID.AddBoolean(HasExtParameterInfos);
770     if (HasExtParameterInfos) {
771       for (auto paramInfo : getExtParameterInfos())
772         ID.AddInteger(paramInfo.getOpaqueValue());
773     }
774     getReturnType().Profile(ID);
775     for (const auto &I : arguments())
776       I.type.Profile(ID);
777   }
778   static void Profile(llvm::FoldingSetNodeID &ID, bool InstanceMethod,
779                       bool ChainCall, bool IsDelegateCall,
780                       const FunctionType::ExtInfo &info,
781                       ArrayRef<ExtParameterInfo> paramInfos,
782                       RequiredArgs required, CanQualType resultType,
783                       ArrayRef<CanQualType> argTypes) {
784     ID.AddInteger(info.getCC());
785     ID.AddBoolean(InstanceMethod);
786     ID.AddBoolean(ChainCall);
787     ID.AddBoolean(IsDelegateCall);
788     ID.AddBoolean(info.getNoReturn());
789     ID.AddBoolean(info.getProducesResult());
790     ID.AddBoolean(info.getNoCallerSavedRegs());
791     ID.AddBoolean(info.getHasRegParm());
792     ID.AddInteger(info.getRegParm());
793     ID.AddBoolean(info.getNoCfCheck());
794     ID.AddBoolean(info.getCmseNSCall());
795     ID.AddInteger(required.getOpaqueData());
796     ID.AddBoolean(!paramInfos.empty());
797     if (!paramInfos.empty()) {
798       for (auto paramInfo : paramInfos)
799         ID.AddInteger(paramInfo.getOpaqueValue());
800     }
801     resultType.Profile(ID);
802     for (ArrayRef<CanQualType>::iterator
803            i = argTypes.begin(), e = argTypes.end(); i != e; ++i) {
804       i->Profile(ID);
805     }
806   }
807 };
808 
809 }  // end namespace CodeGen
810 }  // end namespace clang
811 
812 #endif
813