1//===- BPF.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// BPF ABI Implementation
17//===----------------------------------------------------------------------===//
18
19namespace {
20
21class BPFABIInfo : public DefaultABIInfo {
22public:
23 BPFABIInfo(CodeGenTypes &CGT) : DefaultABIInfo(CGT) {}
24
25 ABIArgInfo classifyArgumentType(QualType Ty) const {
26 Ty = useFirstFieldIfTransparentUnion(Ty);
27
28 if (isAggregateTypeForABI(T: Ty)) {
29 uint64_t Bits = getContext().getTypeSize(T: Ty);
30 if (Bits == 0)
31 return ABIArgInfo::getIgnore();
32
33 // If the aggregate needs 1 or 2 registers, do not use reference.
34 if (Bits <= 128) {
35 llvm::Type *CoerceTy;
36 if (Bits <= 64) {
37 CoerceTy =
38 llvm::IntegerType::get(C&: getVMContext(), NumBits: llvm::alignTo(Value: Bits, Align: 8));
39 } else {
40 llvm::Type *RegTy = llvm::IntegerType::get(C&: getVMContext(), NumBits: 64);
41 CoerceTy = llvm::ArrayType::get(ElementType: RegTy, NumElements: 2);
42 }
43 return ABIArgInfo::getDirect(T: CoerceTy);
44 } else {
45 return getNaturalAlignIndirect(Ty);
46 }
47 }
48
49 if (const EnumType *EnumTy = Ty->getAs<EnumType>())
50 Ty = EnumTy->getDecl()->getIntegerType();
51
52 ASTContext &Context = getContext();
53 if (const auto *EIT = Ty->getAs<BitIntType>())
54 if (EIT->getNumBits() > Context.getTypeSize(T: Context.Int128Ty))
55 return getNaturalAlignIndirect(Ty);
56
57 return (isPromotableIntegerTypeForABI(Ty) ? ABIArgInfo::getExtend(Ty)
58 : ABIArgInfo::getDirect());
59 }
60
61 ABIArgInfo classifyReturnType(QualType RetTy) const {
62 if (RetTy->isVoidType())
63 return ABIArgInfo::getIgnore();
64
65 if (isAggregateTypeForABI(T: RetTy))
66 return getNaturalAlignIndirect(Ty: RetTy);
67
68 // Treat an enum type as its underlying type.
69 if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
70 RetTy = EnumTy->getDecl()->getIntegerType();
71
72 ASTContext &Context = getContext();
73 if (const auto *EIT = RetTy->getAs<BitIntType>())
74 if (EIT->getNumBits() > Context.getTypeSize(T: Context.Int128Ty))
75 return getNaturalAlignIndirect(Ty: RetTy);
76
77 // Caller will do necessary sign/zero extension.
78 return ABIArgInfo::getDirect();
79 }
80
81 void computeInfo(CGFunctionInfo &FI) const override {
82 FI.getReturnInfo() = classifyReturnType(RetTy: FI.getReturnType());
83 for (auto &I : FI.arguments())
84 I.info = classifyArgumentType(Ty: I.type);
85 }
86
87};
88
89class BPFTargetCodeGenInfo : public TargetCodeGenInfo {
90public:
91 BPFTargetCodeGenInfo(CodeGenTypes &CGT)
92 : TargetCodeGenInfo(std::make_unique<BPFABIInfo>(args&: CGT)) {}
93};
94
95}
96
97std::unique_ptr<TargetCodeGenInfo>
98CodeGen::createBPFTargetCodeGenInfo(CodeGenModule &CGM) {
99 return std::make_unique<BPFTargetCodeGenInfo>(args&: CGM.getTypes());
100}
101