xref: /freebsd/contrib/llvm-project/clang/lib/CodeGen/Targets/RISCV.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 //===- RISCV.cpp ----------------------------------------------------------===//
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 #include "ABIInfoImpl.h"
10 #include "TargetInfo.h"
11 
12 using namespace clang;
13 using namespace clang::CodeGen;
14 
15 //===----------------------------------------------------------------------===//
16 // RISC-V ABI Implementation
17 //===----------------------------------------------------------------------===//
18 
19 namespace {
20 class RISCVABIInfo : public DefaultABIInfo {
21 private:
22   // Size of the integer ('x') registers in bits.
23   unsigned XLen;
24   // Size of the floating point ('f') registers in bits. Note that the target
25   // ISA might have a wider FLen than the selected ABI (e.g. an RV32IF target
26   // with soft float ABI has FLen==0).
27   unsigned FLen;
28   const int NumArgGPRs;
29   const int NumArgFPRs;
30   const bool EABI;
31   bool detectFPCCEligibleStructHelper(QualType Ty, CharUnits CurOff,
32                                       llvm::Type *&Field1Ty,
33                                       CharUnits &Field1Off,
34                                       llvm::Type *&Field2Ty,
35                                       CharUnits &Field2Off) const;
36 
37 public:
RISCVABIInfo(CodeGen::CodeGenTypes & CGT,unsigned XLen,unsigned FLen,bool EABI)38   RISCVABIInfo(CodeGen::CodeGenTypes &CGT, unsigned XLen, unsigned FLen,
39                bool EABI)
40       : DefaultABIInfo(CGT), XLen(XLen), FLen(FLen), NumArgGPRs(EABI ? 6 : 8),
41         NumArgFPRs(FLen != 0 ? 8 : 0), EABI(EABI) {}
42 
43   // DefaultABIInfo's classifyReturnType and classifyArgumentType are
44   // non-virtual, but computeInfo is virtual, so we overload it.
45   void computeInfo(CGFunctionInfo &FI) const override;
46 
47   ABIArgInfo classifyArgumentType(QualType Ty, bool IsFixed, int &ArgGPRsLeft,
48                                   int &ArgFPRsLeft) const;
49   ABIArgInfo classifyReturnType(QualType RetTy) const;
50 
51   RValue EmitVAArg(CodeGenFunction &CGF, Address VAListAddr, QualType Ty,
52                    AggValueSlot Slot) const override;
53 
54   ABIArgInfo extendType(QualType Ty) const;
55 
56   bool detectFPCCEligibleStruct(QualType Ty, llvm::Type *&Field1Ty,
57                                 CharUnits &Field1Off, llvm::Type *&Field2Ty,
58                                 CharUnits &Field2Off, int &NeededArgGPRs,
59                                 int &NeededArgFPRs) const;
60   ABIArgInfo coerceAndExpandFPCCEligibleStruct(llvm::Type *Field1Ty,
61                                                CharUnits Field1Off,
62                                                llvm::Type *Field2Ty,
63                                                CharUnits Field2Off) const;
64 
65   ABIArgInfo coerceVLSVector(QualType Ty) const;
66 };
67 } // end anonymous namespace
68 
computeInfo(CGFunctionInfo & FI) const69 void RISCVABIInfo::computeInfo(CGFunctionInfo &FI) const {
70   QualType RetTy = FI.getReturnType();
71   if (!getCXXABI().classifyReturnType(FI))
72     FI.getReturnInfo() = classifyReturnType(RetTy);
73 
74   // IsRetIndirect is true if classifyArgumentType indicated the value should
75   // be passed indirect, or if the type size is a scalar greater than 2*XLen
76   // and not a complex type with elements <= FLen. e.g. fp128 is passed direct
77   // in LLVM IR, relying on the backend lowering code to rewrite the argument
78   // list and pass indirectly on RV32.
79   bool IsRetIndirect = FI.getReturnInfo().getKind() == ABIArgInfo::Indirect;
80   if (!IsRetIndirect && RetTy->isScalarType() &&
81       getContext().getTypeSize(RetTy) > (2 * XLen)) {
82     if (RetTy->isComplexType() && FLen) {
83       QualType EltTy = RetTy->castAs<ComplexType>()->getElementType();
84       IsRetIndirect = getContext().getTypeSize(EltTy) > FLen;
85     } else {
86       // This is a normal scalar > 2*XLen, such as fp128 on RV32.
87       IsRetIndirect = true;
88     }
89   }
90 
91   int ArgGPRsLeft = IsRetIndirect ? NumArgGPRs - 1 : NumArgGPRs;
92   int ArgFPRsLeft = NumArgFPRs;
93   int NumFixedArgs = FI.getNumRequiredArgs();
94 
95   int ArgNum = 0;
96   for (auto &ArgInfo : FI.arguments()) {
97     bool IsFixed = ArgNum < NumFixedArgs;
98     ArgInfo.info =
99         classifyArgumentType(ArgInfo.type, IsFixed, ArgGPRsLeft, ArgFPRsLeft);
100     ArgNum++;
101   }
102 }
103 
104 // Returns true if the struct is a potential candidate for the floating point
105 // calling convention. If this function returns true, the caller is
106 // responsible for checking that if there is only a single field then that
107 // field is a float.
detectFPCCEligibleStructHelper(QualType Ty,CharUnits CurOff,llvm::Type * & Field1Ty,CharUnits & Field1Off,llvm::Type * & Field2Ty,CharUnits & Field2Off) const108 bool RISCVABIInfo::detectFPCCEligibleStructHelper(QualType Ty, CharUnits CurOff,
109                                                   llvm::Type *&Field1Ty,
110                                                   CharUnits &Field1Off,
111                                                   llvm::Type *&Field2Ty,
112                                                   CharUnits &Field2Off) const {
113   bool IsInt = Ty->isIntegralOrEnumerationType();
114   bool IsFloat = Ty->isRealFloatingType();
115 
116   if (IsInt || IsFloat) {
117     uint64_t Size = getContext().getTypeSize(Ty);
118     if (IsInt && Size > XLen)
119       return false;
120     // Can't be eligible if larger than the FP registers. Handling of half
121     // precision values has been specified in the ABI, so don't block those.
122     if (IsFloat && Size > FLen)
123       return false;
124     // Can't be eligible if an integer type was already found (int+int pairs
125     // are not eligible).
126     if (IsInt && Field1Ty && Field1Ty->isIntegerTy())
127       return false;
128     if (!Field1Ty) {
129       Field1Ty = CGT.ConvertType(Ty);
130       Field1Off = CurOff;
131       return true;
132     }
133     if (!Field2Ty) {
134       Field2Ty = CGT.ConvertType(Ty);
135       Field2Off = CurOff;
136       return true;
137     }
138     return false;
139   }
140 
141   if (auto CTy = Ty->getAs<ComplexType>()) {
142     if (Field1Ty)
143       return false;
144     QualType EltTy = CTy->getElementType();
145     if (getContext().getTypeSize(EltTy) > FLen)
146       return false;
147     Field1Ty = CGT.ConvertType(EltTy);
148     Field1Off = CurOff;
149     Field2Ty = Field1Ty;
150     Field2Off = Field1Off + getContext().getTypeSizeInChars(EltTy);
151     return true;
152   }
153 
154   if (const ConstantArrayType *ATy = getContext().getAsConstantArrayType(Ty)) {
155     uint64_t ArraySize = ATy->getZExtSize();
156     QualType EltTy = ATy->getElementType();
157     // Non-zero-length arrays of empty records make the struct ineligible for
158     // the FP calling convention in C++.
159     if (const auto *RTy = EltTy->getAs<RecordType>()) {
160       if (ArraySize != 0 && isa<CXXRecordDecl>(RTy->getDecl()) &&
161           isEmptyRecord(getContext(), EltTy, true, true))
162         return false;
163     }
164     CharUnits EltSize = getContext().getTypeSizeInChars(EltTy);
165     for (uint64_t i = 0; i < ArraySize; ++i) {
166       bool Ret = detectFPCCEligibleStructHelper(EltTy, CurOff, Field1Ty,
167                                                 Field1Off, Field2Ty, Field2Off);
168       if (!Ret)
169         return false;
170       CurOff += EltSize;
171     }
172     return true;
173   }
174 
175   if (const auto *RTy = Ty->getAs<RecordType>()) {
176     // Structures with either a non-trivial destructor or a non-trivial
177     // copy constructor are not eligible for the FP calling convention.
178     if (getRecordArgABI(Ty, CGT.getCXXABI()))
179       return false;
180     if (isEmptyRecord(getContext(), Ty, true, true))
181       return true;
182     const RecordDecl *RD = RTy->getDecl();
183     // Unions aren't eligible unless they're empty (which is caught above).
184     if (RD->isUnion())
185       return false;
186     const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
187     // If this is a C++ record, check the bases first.
188     if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
189       for (const CXXBaseSpecifier &B : CXXRD->bases()) {
190         const auto *BDecl =
191             cast<CXXRecordDecl>(B.getType()->castAs<RecordType>()->getDecl());
192         CharUnits BaseOff = Layout.getBaseClassOffset(BDecl);
193         bool Ret = detectFPCCEligibleStructHelper(B.getType(), CurOff + BaseOff,
194                                                   Field1Ty, Field1Off, Field2Ty,
195                                                   Field2Off);
196         if (!Ret)
197           return false;
198       }
199     }
200     int ZeroWidthBitFieldCount = 0;
201     for (const FieldDecl *FD : RD->fields()) {
202       uint64_t FieldOffInBits = Layout.getFieldOffset(FD->getFieldIndex());
203       QualType QTy = FD->getType();
204       if (FD->isBitField()) {
205         unsigned BitWidth = FD->getBitWidthValue(getContext());
206         // Allow a bitfield with a type greater than XLen as long as the
207         // bitwidth is XLen or less.
208         if (getContext().getTypeSize(QTy) > XLen && BitWidth <= XLen)
209           QTy = getContext().getIntTypeForBitwidth(XLen, false);
210         if (BitWidth == 0) {
211           ZeroWidthBitFieldCount++;
212           continue;
213         }
214       }
215 
216       bool Ret = detectFPCCEligibleStructHelper(
217           QTy, CurOff + getContext().toCharUnitsFromBits(FieldOffInBits),
218           Field1Ty, Field1Off, Field2Ty, Field2Off);
219       if (!Ret)
220         return false;
221 
222       // As a quirk of the ABI, zero-width bitfields aren't ignored for fp+fp
223       // or int+fp structs, but are ignored for a struct with an fp field and
224       // any number of zero-width bitfields.
225       if (Field2Ty && ZeroWidthBitFieldCount > 0)
226         return false;
227     }
228     return Field1Ty != nullptr;
229   }
230 
231   return false;
232 }
233 
234 // Determine if a struct is eligible for passing according to the floating
235 // point calling convention (i.e., when flattened it contains a single fp
236 // value, fp+fp, or int+fp of appropriate size). If so, NeededArgFPRs and
237 // NeededArgGPRs are incremented appropriately.
detectFPCCEligibleStruct(QualType Ty,llvm::Type * & Field1Ty,CharUnits & Field1Off,llvm::Type * & Field2Ty,CharUnits & Field2Off,int & NeededArgGPRs,int & NeededArgFPRs) const238 bool RISCVABIInfo::detectFPCCEligibleStruct(QualType Ty, llvm::Type *&Field1Ty,
239                                             CharUnits &Field1Off,
240                                             llvm::Type *&Field2Ty,
241                                             CharUnits &Field2Off,
242                                             int &NeededArgGPRs,
243                                             int &NeededArgFPRs) const {
244   Field1Ty = nullptr;
245   Field2Ty = nullptr;
246   NeededArgGPRs = 0;
247   NeededArgFPRs = 0;
248   bool IsCandidate = detectFPCCEligibleStructHelper(
249       Ty, CharUnits::Zero(), Field1Ty, Field1Off, Field2Ty, Field2Off);
250   if (!Field1Ty)
251     return false;
252   // Not really a candidate if we have a single int but no float.
253   if (Field1Ty && !Field2Ty && !Field1Ty->isFloatingPointTy())
254     return false;
255   if (!IsCandidate)
256     return false;
257   if (Field1Ty && Field1Ty->isFloatingPointTy())
258     NeededArgFPRs++;
259   else if (Field1Ty)
260     NeededArgGPRs++;
261   if (Field2Ty && Field2Ty->isFloatingPointTy())
262     NeededArgFPRs++;
263   else if (Field2Ty)
264     NeededArgGPRs++;
265   return true;
266 }
267 
268 // Call getCoerceAndExpand for the two-element flattened struct described by
269 // Field1Ty, Field1Off, Field2Ty, Field2Off. This method will create an
270 // appropriate coerceToType and unpaddedCoerceToType.
coerceAndExpandFPCCEligibleStruct(llvm::Type * Field1Ty,CharUnits Field1Off,llvm::Type * Field2Ty,CharUnits Field2Off) const271 ABIArgInfo RISCVABIInfo::coerceAndExpandFPCCEligibleStruct(
272     llvm::Type *Field1Ty, CharUnits Field1Off, llvm::Type *Field2Ty,
273     CharUnits Field2Off) const {
274   SmallVector<llvm::Type *, 3> CoerceElts;
275   SmallVector<llvm::Type *, 2> UnpaddedCoerceElts;
276   if (!Field1Off.isZero())
277     CoerceElts.push_back(llvm::ArrayType::get(
278         llvm::Type::getInt8Ty(getVMContext()), Field1Off.getQuantity()));
279 
280   CoerceElts.push_back(Field1Ty);
281   UnpaddedCoerceElts.push_back(Field1Ty);
282 
283   if (!Field2Ty) {
284     return ABIArgInfo::getCoerceAndExpand(
285         llvm::StructType::get(getVMContext(), CoerceElts, !Field1Off.isZero()),
286         UnpaddedCoerceElts[0]);
287   }
288 
289   CharUnits Field2Align =
290       CharUnits::fromQuantity(getDataLayout().getABITypeAlign(Field2Ty));
291   CharUnits Field1End = Field1Off +
292       CharUnits::fromQuantity(getDataLayout().getTypeStoreSize(Field1Ty));
293   CharUnits Field2OffNoPadNoPack = Field1End.alignTo(Field2Align);
294 
295   CharUnits Padding = CharUnits::Zero();
296   if (Field2Off > Field2OffNoPadNoPack)
297     Padding = Field2Off - Field2OffNoPadNoPack;
298   else if (Field2Off != Field2Align && Field2Off > Field1End)
299     Padding = Field2Off - Field1End;
300 
301   bool IsPacked = !Field2Off.isMultipleOf(Field2Align);
302 
303   if (!Padding.isZero())
304     CoerceElts.push_back(llvm::ArrayType::get(
305         llvm::Type::getInt8Ty(getVMContext()), Padding.getQuantity()));
306 
307   CoerceElts.push_back(Field2Ty);
308   UnpaddedCoerceElts.push_back(Field2Ty);
309 
310   auto CoerceToType =
311       llvm::StructType::get(getVMContext(), CoerceElts, IsPacked);
312   auto UnpaddedCoerceToType =
313       llvm::StructType::get(getVMContext(), UnpaddedCoerceElts, IsPacked);
314 
315   return ABIArgInfo::getCoerceAndExpand(CoerceToType, UnpaddedCoerceToType);
316 }
317 
318 // Fixed-length RVV vectors are represented as scalable vectors in function
319 // args/return and must be coerced from fixed vectors.
coerceVLSVector(QualType Ty) const320 ABIArgInfo RISCVABIInfo::coerceVLSVector(QualType Ty) const {
321   assert(Ty->isVectorType() && "expected vector type!");
322 
323   const auto *VT = Ty->castAs<VectorType>();
324   assert(VT->getElementType()->isBuiltinType() && "expected builtin type!");
325 
326   auto VScale =
327       getContext().getTargetInfo().getVScaleRange(getContext().getLangOpts());
328 
329   unsigned NumElts = VT->getNumElements();
330   llvm::Type *EltType;
331   if (VT->getVectorKind() == VectorKind::RVVFixedLengthMask) {
332     NumElts *= 8;
333     EltType = llvm::Type::getInt1Ty(getVMContext());
334   } else {
335     assert(VT->getVectorKind() == VectorKind::RVVFixedLengthData &&
336            "Unexpected vector kind");
337     EltType = CGT.ConvertType(VT->getElementType());
338   }
339 
340   // The MinNumElts is simplified from equation:
341   // NumElts / VScale =
342   //  (EltSize * NumElts / (VScale * RVVBitsPerBlock))
343   //    * (RVVBitsPerBlock / EltSize)
344   llvm::ScalableVectorType *ResType =
345       llvm::ScalableVectorType::get(EltType, NumElts / VScale->first);
346   return ABIArgInfo::getDirect(ResType);
347 }
348 
classifyArgumentType(QualType Ty,bool IsFixed,int & ArgGPRsLeft,int & ArgFPRsLeft) const349 ABIArgInfo RISCVABIInfo::classifyArgumentType(QualType Ty, bool IsFixed,
350                                               int &ArgGPRsLeft,
351                                               int &ArgFPRsLeft) const {
352   assert(ArgGPRsLeft <= NumArgGPRs && "Arg GPR tracking underflow");
353   Ty = useFirstFieldIfTransparentUnion(Ty);
354 
355   // Structures with either a non-trivial destructor or a non-trivial
356   // copy constructor are always passed indirectly.
357   if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI())) {
358     if (ArgGPRsLeft)
359       ArgGPRsLeft -= 1;
360     return getNaturalAlignIndirect(Ty, /*ByVal=*/RAA ==
361                                            CGCXXABI::RAA_DirectInMemory);
362   }
363 
364   uint64_t Size = getContext().getTypeSize(Ty);
365 
366   // Ignore empty structs/unions whose size is zero. According to the calling
367   // convention empty structs/unions are required to be sized types in C++.
368   if (isEmptyRecord(getContext(), Ty, true) && Size == 0)
369     return ABIArgInfo::getIgnore();
370 
371   // Pass floating point values via FPRs if possible.
372   if (IsFixed && Ty->isFloatingType() && !Ty->isComplexType() &&
373       FLen >= Size && ArgFPRsLeft) {
374     ArgFPRsLeft--;
375     return ABIArgInfo::getDirect();
376   }
377 
378   // Complex types for the hard float ABI must be passed direct rather than
379   // using CoerceAndExpand.
380   if (IsFixed && Ty->isComplexType() && FLen && ArgFPRsLeft >= 2) {
381     QualType EltTy = Ty->castAs<ComplexType>()->getElementType();
382     if (getContext().getTypeSize(EltTy) <= FLen) {
383       ArgFPRsLeft -= 2;
384       return ABIArgInfo::getDirect();
385     }
386   }
387 
388   if (IsFixed && FLen && Ty->isStructureOrClassType()) {
389     llvm::Type *Field1Ty = nullptr;
390     llvm::Type *Field2Ty = nullptr;
391     CharUnits Field1Off = CharUnits::Zero();
392     CharUnits Field2Off = CharUnits::Zero();
393     int NeededArgGPRs = 0;
394     int NeededArgFPRs = 0;
395     bool IsCandidate =
396         detectFPCCEligibleStruct(Ty, Field1Ty, Field1Off, Field2Ty, Field2Off,
397                                  NeededArgGPRs, NeededArgFPRs);
398     if (IsCandidate && NeededArgGPRs <= ArgGPRsLeft &&
399         NeededArgFPRs <= ArgFPRsLeft) {
400       ArgGPRsLeft -= NeededArgGPRs;
401       ArgFPRsLeft -= NeededArgFPRs;
402       return coerceAndExpandFPCCEligibleStruct(Field1Ty, Field1Off, Field2Ty,
403                                                Field2Off);
404     }
405   }
406 
407   uint64_t NeededAlign = getContext().getTypeAlign(Ty);
408   // Determine the number of GPRs needed to pass the current argument
409   // according to the ABI. 2*XLen-aligned varargs are passed in "aligned"
410   // register pairs, so may consume 3 registers.
411   // TODO: To be compatible with GCC's behaviors, we don't align registers
412   // currently if we are using ILP32E calling convention. This behavior may be
413   // changed when RV32E/ILP32E is ratified.
414   int NeededArgGPRs = 1;
415   if (!IsFixed && NeededAlign == 2 * XLen)
416     NeededArgGPRs = 2 + (EABI && XLen == 32 ? 0 : (ArgGPRsLeft % 2));
417   else if (Size > XLen && Size <= 2 * XLen)
418     NeededArgGPRs = 2;
419 
420   if (NeededArgGPRs > ArgGPRsLeft) {
421     NeededArgGPRs = ArgGPRsLeft;
422   }
423 
424   ArgGPRsLeft -= NeededArgGPRs;
425 
426   if (!isAggregateTypeForABI(Ty) && !Ty->isVectorType()) {
427     // Treat an enum type as its underlying type.
428     if (const EnumType *EnumTy = Ty->getAs<EnumType>())
429       Ty = EnumTy->getDecl()->getIntegerType();
430 
431     // All integral types are promoted to XLen width
432     if (Size < XLen && Ty->isIntegralOrEnumerationType()) {
433       return extendType(Ty);
434     }
435 
436     if (const auto *EIT = Ty->getAs<BitIntType>()) {
437       if (EIT->getNumBits() < XLen)
438         return extendType(Ty);
439       if (EIT->getNumBits() > 128 ||
440           (!getContext().getTargetInfo().hasInt128Type() &&
441            EIT->getNumBits() > 64))
442         return getNaturalAlignIndirect(Ty, /*ByVal=*/false);
443     }
444 
445     ABIArgInfo Info = ABIArgInfo::getDirect();
446 
447     // If it is tuple type, it can't be flattened.
448     if (llvm::StructType *STy = dyn_cast<llvm::StructType>(CGT.ConvertType(Ty)))
449       Info.setCanBeFlattened(!STy->containsHomogeneousScalableVectorTypes());
450 
451     return Info;
452   }
453 
454   if (const VectorType *VT = Ty->getAs<VectorType>())
455     if (VT->getVectorKind() == VectorKind::RVVFixedLengthData ||
456         VT->getVectorKind() == VectorKind::RVVFixedLengthMask)
457       return coerceVLSVector(Ty);
458 
459   // Aggregates which are <= 2*XLen will be passed in registers if possible,
460   // so coerce to integers.
461   if (Size <= 2 * XLen) {
462     unsigned Alignment = getContext().getTypeAlign(Ty);
463 
464     // Use a single XLen int if possible, 2*XLen if 2*XLen alignment is
465     // required, and a 2-element XLen array if only XLen alignment is required.
466     if (Size <= XLen) {
467       return ABIArgInfo::getDirect(
468           llvm::IntegerType::get(getVMContext(), XLen));
469     } else if (Alignment == 2 * XLen) {
470       return ABIArgInfo::getDirect(
471           llvm::IntegerType::get(getVMContext(), 2 * XLen));
472     } else {
473       return ABIArgInfo::getDirect(llvm::ArrayType::get(
474           llvm::IntegerType::get(getVMContext(), XLen), 2));
475     }
476   }
477   return getNaturalAlignIndirect(Ty, /*ByVal=*/false);
478 }
479 
classifyReturnType(QualType RetTy) const480 ABIArgInfo RISCVABIInfo::classifyReturnType(QualType RetTy) const {
481   if (RetTy->isVoidType())
482     return ABIArgInfo::getIgnore();
483 
484   int ArgGPRsLeft = 2;
485   int ArgFPRsLeft = FLen ? 2 : 0;
486 
487   // The rules for return and argument types are the same, so defer to
488   // classifyArgumentType.
489   return classifyArgumentType(RetTy, /*IsFixed=*/true, ArgGPRsLeft,
490                               ArgFPRsLeft);
491 }
492 
EmitVAArg(CodeGenFunction & CGF,Address VAListAddr,QualType Ty,AggValueSlot Slot) const493 RValue RISCVABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
494                                QualType Ty, AggValueSlot Slot) const {
495   CharUnits SlotSize = CharUnits::fromQuantity(XLen / 8);
496 
497   // Empty records are ignored for parameter passing purposes.
498   if (isEmptyRecord(getContext(), Ty, true))
499     return Slot.asRValue();
500 
501   auto TInfo = getContext().getTypeInfoInChars(Ty);
502 
503   // TODO: To be compatible with GCC's behaviors, we force arguments with
504   // 2×XLEN-bit alignment and size at most 2×XLEN bits like `long long`,
505   // `unsigned long long` and `double` to have 4-byte alignment. This
506   // behavior may be changed when RV32E/ILP32E is ratified.
507   if (EABI && XLen == 32)
508     TInfo.Align = std::min(TInfo.Align, CharUnits::fromQuantity(4));
509 
510   // Arguments bigger than 2*Xlen bytes are passed indirectly.
511   bool IsIndirect = TInfo.Width > 2 * SlotSize;
512 
513   return emitVoidPtrVAArg(CGF, VAListAddr, Ty, IsIndirect, TInfo, SlotSize,
514                           /*AllowHigherAlign=*/true, Slot);
515 }
516 
extendType(QualType Ty) const517 ABIArgInfo RISCVABIInfo::extendType(QualType Ty) const {
518   int TySize = getContext().getTypeSize(Ty);
519   // RV64 ABI requires unsigned 32 bit integers to be sign extended.
520   if (XLen == 64 && Ty->isUnsignedIntegerOrEnumerationType() && TySize == 32)
521     return ABIArgInfo::getSignExtend(Ty);
522   return ABIArgInfo::getExtend(Ty);
523 }
524 
525 namespace {
526 class RISCVTargetCodeGenInfo : public TargetCodeGenInfo {
527 public:
RISCVTargetCodeGenInfo(CodeGen::CodeGenTypes & CGT,unsigned XLen,unsigned FLen,bool EABI)528   RISCVTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT, unsigned XLen,
529                          unsigned FLen, bool EABI)
530       : TargetCodeGenInfo(
531             std::make_unique<RISCVABIInfo>(CGT, XLen, FLen, EABI)) {
532     SwiftInfo =
533         std::make_unique<SwiftABIInfo>(CGT, /*SwiftErrorInRegister=*/false);
534   }
535 
setTargetAttributes(const Decl * D,llvm::GlobalValue * GV,CodeGen::CodeGenModule & CGM) const536   void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
537                            CodeGen::CodeGenModule &CGM) const override {
538     const auto *FD = dyn_cast_or_null<FunctionDecl>(D);
539     if (!FD) return;
540 
541     const auto *Attr = FD->getAttr<RISCVInterruptAttr>();
542     if (!Attr)
543       return;
544 
545     const char *Kind;
546     switch (Attr->getInterrupt()) {
547     case RISCVInterruptAttr::supervisor: Kind = "supervisor"; break;
548     case RISCVInterruptAttr::machine: Kind = "machine"; break;
549     }
550 
551     auto *Fn = cast<llvm::Function>(GV);
552 
553     Fn->addFnAttr("interrupt", Kind);
554   }
555 };
556 } // namespace
557 
558 std::unique_ptr<TargetCodeGenInfo>
createRISCVTargetCodeGenInfo(CodeGenModule & CGM,unsigned XLen,unsigned FLen,bool EABI)559 CodeGen::createRISCVTargetCodeGenInfo(CodeGenModule &CGM, unsigned XLen,
560                                       unsigned FLen, bool EABI) {
561   return std::make_unique<RISCVTargetCodeGenInfo>(CGM.getTypes(), XLen, FLen,
562                                                   EABI);
563 }
564