1//===- CSKY.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
12using namespace clang;
13using namespace clang::CodeGen;
14
15//===----------------------------------------------------------------------===//
16// CSKY ABI Implementation
17//===----------------------------------------------------------------------===//
18namespace {
19class CSKYABIInfo : public DefaultABIInfo {
20 static const int NumArgGPRs = 4;
21 static const int NumArgFPRs = 4;
22
23 static const unsigned XLen = 32;
24 unsigned FLen;
25
26public:
27 CSKYABIInfo(CodeGen::CodeGenTypes &CGT, unsigned FLen)
28 : DefaultABIInfo(CGT), FLen(FLen) {}
29
30 void computeInfo(CGFunctionInfo &FI) const override;
31 ABIArgInfo classifyArgumentType(QualType Ty, int &ArgGPRsLeft,
32 int &ArgFPRsLeft,
33 bool isReturnType = false) const;
34 ABIArgInfo classifyReturnType(QualType RetTy) const;
35
36 RValue EmitVAArg(CodeGenFunction &CGF, Address VAListAddr, QualType Ty,
37 AggValueSlot Slot) const override;
38};
39
40} // end anonymous namespace
41
42void CSKYABIInfo::computeInfo(CGFunctionInfo &FI) const {
43 QualType RetTy = FI.getReturnType();
44 if (!getCXXABI().classifyReturnType(FI))
45 FI.getReturnInfo() = classifyReturnType(RetTy);
46
47 bool IsRetIndirect = FI.getReturnInfo().getKind() == ABIArgInfo::Indirect;
48
49 // We must track the number of GPRs used in order to conform to the CSKY
50 // ABI, as integer scalars passed in registers should have signext/zeroext
51 // when promoted.
52 int ArgGPRsLeft = IsRetIndirect ? NumArgGPRs - 1 : NumArgGPRs;
53 int ArgFPRsLeft = FLen ? NumArgFPRs : 0;
54
55 for (auto &ArgInfo : FI.arguments()) {
56 ArgInfo.info = classifyArgumentType(Ty: ArgInfo.type, ArgGPRsLeft, ArgFPRsLeft);
57 }
58}
59
60RValue CSKYABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
61 QualType Ty, AggValueSlot Slot) const {
62 CharUnits SlotSize = CharUnits::fromQuantity(Quantity: XLen / 8);
63
64 // Empty records are ignored for parameter passing purposes.
65 if (isEmptyRecord(Context&: getContext(), T: Ty, AllowArrays: true))
66 return Slot.asRValue();
67
68 auto TInfo = getContext().getTypeInfoInChars(T: Ty);
69
70 return emitVoidPtrVAArg(CGF, VAListAddr, ValueTy: Ty, IsIndirect: false, ValueInfo: TInfo, SlotSizeAndAlign: SlotSize,
71 /*AllowHigherAlign=*/true, Slot);
72}
73
74ABIArgInfo CSKYABIInfo::classifyArgumentType(QualType Ty, int &ArgGPRsLeft,
75 int &ArgFPRsLeft,
76 bool isReturnType) const {
77 assert(ArgGPRsLeft <= NumArgGPRs && "Arg GPR tracking underflow");
78 Ty = useFirstFieldIfTransparentUnion(Ty);
79
80 // Structures with either a non-trivial destructor or a non-trivial
81 // copy constructor are always passed indirectly.
82 if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(T: Ty, CXXABI&: getCXXABI())) {
83 if (ArgGPRsLeft)
84 ArgGPRsLeft -= 1;
85 return getNaturalAlignIndirect(
86 Ty, /*AddrSpace=*/getDataLayout().getAllocaAddrSpace(),
87 /*ByVal=*/RAA == CGCXXABI::RAA_DirectInMemory);
88 }
89
90 // Ignore empty structs/unions.
91 if (isEmptyRecord(Context&: getContext(), T: Ty, AllowArrays: true))
92 return ABIArgInfo::getIgnore();
93
94 if (!Ty->getAsUnionType())
95 if (const Type *SeltTy = isSingleElementStruct(T: Ty, Context&: getContext()))
96 return ABIArgInfo::getDirect(T: CGT.ConvertType(T: QualType(SeltTy, 0)));
97
98 uint64_t Size = getContext().getTypeSize(T: Ty);
99 // Pass floating point values via FPRs if possible.
100 if (Ty->isFloatingType() && !Ty->isComplexType() && FLen >= Size &&
101 ArgFPRsLeft) {
102 ArgFPRsLeft--;
103 return ABIArgInfo::getDirect();
104 }
105
106 // Complex types for the hard float ABI must be passed direct rather than
107 // using CoerceAndExpand.
108 if (Ty->isComplexType() && FLen && !isReturnType) {
109 QualType EltTy = Ty->castAs<ComplexType>()->getElementType();
110 if (getContext().getTypeSize(T: EltTy) <= FLen) {
111 ArgFPRsLeft -= 2;
112 return ABIArgInfo::getDirect();
113 }
114 }
115
116 if (!isAggregateTypeForABI(T: Ty)) {
117 // Treat an enum type as its underlying type.
118 if (const EnumType *EnumTy = Ty->getAs<EnumType>())
119 Ty = EnumTy->getDecl()->getIntegerType();
120
121 // All integral types are promoted to XLen width, unless passed on the
122 // stack.
123 if (Size < XLen && Ty->isIntegralOrEnumerationType())
124 return ABIArgInfo::getExtend(Ty);
125
126 if (const auto *EIT = Ty->getAs<BitIntType>()) {
127 if (EIT->getNumBits() < XLen)
128 return ABIArgInfo::getExtend(Ty);
129 }
130
131 return ABIArgInfo::getDirect();
132 }
133
134 // For argument type, the first 4*XLen parts of aggregate will be passed
135 // in registers, and the rest will be passed in stack.
136 // So we can coerce to integers directly and let backend handle it correctly.
137 // For return type, aggregate which <= 2*XLen will be returned in registers.
138 // Otherwise, aggregate will be returned indirectly.
139 if (!isReturnType || (isReturnType && Size <= 2 * XLen)) {
140 if (Size <= XLen) {
141 return ABIArgInfo::getDirect(
142 T: llvm::IntegerType::get(C&: getVMContext(), NumBits: XLen));
143 } else {
144 return ABIArgInfo::getDirect(T: llvm::ArrayType::get(
145 ElementType: llvm::IntegerType::get(C&: getVMContext(), NumBits: XLen), NumElements: (Size + 31) / XLen));
146 }
147 }
148 return getNaturalAlignIndirect(Ty, AddrSpace: getDataLayout().getAllocaAddrSpace(),
149 /*ByVal=*/false);
150}
151
152ABIArgInfo CSKYABIInfo::classifyReturnType(QualType RetTy) const {
153 if (RetTy->isVoidType())
154 return ABIArgInfo::getIgnore();
155
156 int ArgGPRsLeft = 2;
157 int ArgFPRsLeft = FLen ? 1 : 0;
158
159 // The rules for return and argument types are the same, so defer to
160 // classifyArgumentType.
161 return classifyArgumentType(Ty: RetTy, ArgGPRsLeft, ArgFPRsLeft, isReturnType: true);
162}
163
164namespace {
165class CSKYTargetCodeGenInfo : public TargetCodeGenInfo {
166public:
167 CSKYTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT, unsigned FLen)
168 : TargetCodeGenInfo(std::make_unique<CSKYABIInfo>(args&: CGT, args&: FLen)) {}
169};
170} // end anonymous namespace
171
172std::unique_ptr<TargetCodeGenInfo>
173CodeGen::createCSKYTargetCodeGenInfo(CodeGenModule &CGM, unsigned FLen) {
174 return std::make_unique<CSKYTargetCodeGenInfo>(args&: CGM.getTypes(), args&: FLen);
175}
176