1//===-- VEAsmBackend.cpp - VE Assembler Backend ---------------------------===//
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 "MCTargetDesc/VEFixupKinds.h"
10#include "MCTargetDesc/VEMCTargetDesc.h"
11#include "llvm/MC/MCAsmBackend.h"
12#include "llvm/MC/MCELFObjectWriter.h"
13#include "llvm/MC/MCExpr.h"
14#include "llvm/MC/MCObjectWriter.h"
15#include "llvm/MC/MCSubtargetInfo.h"
16#include "llvm/MC/MCValue.h"
17#include "llvm/MC/TargetRegistry.h"
18#include "llvm/Support/EndianStream.h"
19
20using namespace llvm;
21
22static uint64_t adjustFixupValue(unsigned Kind, uint64_t Value) {
23 switch (Kind) {
24 default:
25 llvm_unreachable("Unknown fixup kind!");
26 case FK_Data_1:
27 case FK_Data_2:
28 case FK_Data_4:
29 case FK_Data_8:
30 return Value;
31 case VE::fixup_ve_hi32:
32 case VE::fixup_ve_pc_hi32:
33 case VE::fixup_ve_got_hi32:
34 case VE::fixup_ve_gotoff_hi32:
35 case VE::fixup_ve_plt_hi32:
36 case VE::fixup_ve_tls_gd_hi32:
37 case VE::fixup_ve_tpoff_hi32:
38 return (Value >> 32) & 0xffffffff;
39 case VE::fixup_ve_reflong:
40 case VE::fixup_ve_srel32:
41 case VE::fixup_ve_lo32:
42 case VE::fixup_ve_pc_lo32:
43 case VE::fixup_ve_got_lo32:
44 case VE::fixup_ve_gotoff_lo32:
45 case VE::fixup_ve_plt_lo32:
46 case VE::fixup_ve_tls_gd_lo32:
47 case VE::fixup_ve_tpoff_lo32:
48 return Value & 0xffffffff;
49 }
50}
51
52/// getFixupKindNumBytes - The number of bytes the fixup may change.
53static unsigned getFixupKindNumBytes(unsigned Kind) {
54 switch (Kind) {
55 default:
56 llvm_unreachable("Unknown fixup kind!");
57 case FK_Data_1:
58 return 1;
59 case FK_Data_2:
60 return 2;
61 case FK_Data_4:
62 case VE::fixup_ve_reflong:
63 case VE::fixup_ve_srel32:
64 case VE::fixup_ve_hi32:
65 case VE::fixup_ve_lo32:
66 case VE::fixup_ve_pc_hi32:
67 case VE::fixup_ve_pc_lo32:
68 case VE::fixup_ve_got_hi32:
69 case VE::fixup_ve_got_lo32:
70 case VE::fixup_ve_gotoff_hi32:
71 case VE::fixup_ve_gotoff_lo32:
72 case VE::fixup_ve_plt_hi32:
73 case VE::fixup_ve_plt_lo32:
74 case VE::fixup_ve_tls_gd_hi32:
75 case VE::fixup_ve_tls_gd_lo32:
76 case VE::fixup_ve_tpoff_hi32:
77 case VE::fixup_ve_tpoff_lo32:
78 return 4;
79 case FK_Data_8:
80 return 8;
81 }
82}
83
84namespace {
85class VEAsmBackend : public MCAsmBackend {
86protected:
87 const Target &TheTarget;
88
89public:
90 VEAsmBackend(const Target &T)
91 : MCAsmBackend(llvm::endianness::little), TheTarget(T) {}
92
93 MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override {
94 const static MCFixupKindInfo Infos[VE::NumTargetFixupKinds] = {
95 // name, offset, bits, flags
96 {.Name: "fixup_ve_reflong", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_srel32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
97 {.Name: "fixup_ve_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
98 {.Name: "fixup_ve_pc_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_pc_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
99 {.Name: "fixup_ve_got_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_got_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
100 {.Name: "fixup_ve_gotoff_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_gotoff_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
101 {.Name: "fixup_ve_plt_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_plt_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
102 {.Name: "fixup_ve_tls_gd_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_tls_gd_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
103 {.Name: "fixup_ve_tpoff_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0}, {.Name: "fixup_ve_tpoff_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
104 };
105
106 if (Kind < FirstTargetFixupKind)
107 return MCAsmBackend::getFixupKindInfo(Kind);
108
109 assert(unsigned(Kind - FirstTargetFixupKind) < VE::NumTargetFixupKinds &&
110 "Invalid kind!");
111 return Infos[Kind - FirstTargetFixupKind];
112 }
113
114 void applyFixup(const MCFragment &, const MCFixup &, const MCValue &,
115 uint8_t *, uint64_t Value, bool IsResolved) override;
116
117 bool mayNeedRelaxation(unsigned Opcode, ArrayRef<MCOperand> Operands,
118 const MCSubtargetInfo &STI) const override {
119 // Not implemented yet. For example, if we have a branch with
120 // lager than SIMM32 immediate value, we want to relaxation such
121 // branch instructions.
122 return false;
123 }
124
125 bool writeNopData(raw_ostream &OS, uint64_t Count,
126 const MCSubtargetInfo *STI) const override {
127 if ((Count % 8) != 0)
128 return false;
129
130 for (uint64_t i = 0; i < Count; i += 8)
131 support::endian::write<uint64_t>(os&: OS, value: 0x7900000000000000ULL,
132 endian: llvm::endianness::little);
133
134 return true;
135 }
136};
137
138class ELFVEAsmBackend : public VEAsmBackend {
139 Triple::OSType OSType;
140
141public:
142 ELFVEAsmBackend(const Target &T, Triple::OSType OSType)
143 : VEAsmBackend(T), OSType(OSType) {}
144
145 std::unique_ptr<MCObjectTargetWriter>
146 createObjectTargetWriter() const override {
147 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(OSType);
148 return createVEELFObjectWriter(OSABI);
149 }
150};
151} // end anonymous namespace
152
153void VEAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
154 const MCValue &Target, uint8_t *Data,
155 uint64_t Value, bool IsResolved) {
156 switch (Fixup.getKind()) {
157 case VE::fixup_ve_tls_gd_hi32:
158 case VE::fixup_ve_tls_gd_lo32:
159 case VE::fixup_ve_tpoff_hi32:
160 case VE::fixup_ve_tpoff_lo32:
161 IsResolved = false;
162 break;
163 }
164 maybeAddReloc(F, Fixup, Target, Value, IsResolved);
165 Value = adjustFixupValue(Kind: Fixup.getKind(), Value);
166 if (!Value)
167 return; // Doesn't change encoding.
168
169 MCFixupKindInfo Info = getFixupKindInfo(Kind: Fixup.getKind());
170
171 // Shift the value into position.
172 Value <<= Info.TargetOffset;
173
174 unsigned NumBytes = getFixupKindNumBytes(Kind: Fixup.getKind());
175 assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
176 "Invalid fixup offset!");
177 // For each byte of the fragment that the fixup touches, mask in the bits
178 // from the fixup value. The Value has been "split up" into the
179 // appropriate bitfields above.
180 for (unsigned i = 0; i != NumBytes; ++i) {
181 unsigned Idx = Endian == llvm::endianness::little ? i : (NumBytes - 1) - i;
182 Data[Idx] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
183 }
184}
185
186MCAsmBackend *llvm::createVEAsmBackend(const Target &T,
187 const MCSubtargetInfo &STI,
188 const MCRegisterInfo &MRI,
189 const MCTargetOptions &Options) {
190 return new ELFVEAsmBackend(T, STI.getTargetTriple().getOS());
191}
192