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/MCFixupKindInfo.h"
15#include "llvm/MC/MCObjectWriter.h"
16#include "llvm/MC/MCSubtargetInfo.h"
17#include "llvm/MC/MCValue.h"
18#include "llvm/MC/TargetRegistry.h"
19#include "llvm/Support/EndianStream.h"
20
21using namespace llvm;
22
23static uint64_t adjustFixupValue(unsigned Kind, uint64_t Value) {
24 switch (Kind) {
25 default:
26 llvm_unreachable("Unknown fixup kind!");
27 case FK_Data_1:
28 case FK_Data_2:
29 case FK_Data_4:
30 case FK_Data_8:
31 case FK_PCRel_1:
32 case FK_PCRel_2:
33 case FK_PCRel_4:
34 case FK_PCRel_8:
35 return Value;
36 case VE::fixup_ve_hi32:
37 case VE::fixup_ve_pc_hi32:
38 case VE::fixup_ve_got_hi32:
39 case VE::fixup_ve_gotoff_hi32:
40 case VE::fixup_ve_plt_hi32:
41 case VE::fixup_ve_tls_gd_hi32:
42 case VE::fixup_ve_tpoff_hi32:
43 return (Value >> 32) & 0xffffffff;
44 case VE::fixup_ve_reflong:
45 case VE::fixup_ve_srel32:
46 case VE::fixup_ve_lo32:
47 case VE::fixup_ve_pc_lo32:
48 case VE::fixup_ve_got_lo32:
49 case VE::fixup_ve_gotoff_lo32:
50 case VE::fixup_ve_plt_lo32:
51 case VE::fixup_ve_tls_gd_lo32:
52 case VE::fixup_ve_tpoff_lo32:
53 return Value & 0xffffffff;
54 }
55}
56
57/// getFixupKindNumBytes - The number of bytes the fixup may change.
58static unsigned getFixupKindNumBytes(unsigned Kind) {
59 switch (Kind) {
60 default:
61 llvm_unreachable("Unknown fixup kind!");
62 case FK_Data_1:
63 case FK_PCRel_1:
64 return 1;
65 case FK_Data_2:
66 case FK_PCRel_2:
67 return 2;
68 return 4;
69 case FK_Data_4:
70 case FK_PCRel_4:
71 case VE::fixup_ve_reflong:
72 case VE::fixup_ve_srel32:
73 case VE::fixup_ve_hi32:
74 case VE::fixup_ve_lo32:
75 case VE::fixup_ve_pc_hi32:
76 case VE::fixup_ve_pc_lo32:
77 case VE::fixup_ve_got_hi32:
78 case VE::fixup_ve_got_lo32:
79 case VE::fixup_ve_gotoff_hi32:
80 case VE::fixup_ve_gotoff_lo32:
81 case VE::fixup_ve_plt_hi32:
82 case VE::fixup_ve_plt_lo32:
83 case VE::fixup_ve_tls_gd_hi32:
84 case VE::fixup_ve_tls_gd_lo32:
85 case VE::fixup_ve_tpoff_hi32:
86 case VE::fixup_ve_tpoff_lo32:
87 return 4;
88 case FK_Data_8:
89 case FK_PCRel_8:
90 return 8;
91 }
92}
93
94namespace {
95class VEAsmBackend : public MCAsmBackend {
96protected:
97 const Target &TheTarget;
98
99public:
100 VEAsmBackend(const Target &T)
101 : MCAsmBackend(llvm::endianness::little), TheTarget(T) {}
102
103 unsigned getNumFixupKinds() const override { return VE::NumTargetFixupKinds; }
104
105 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override {
106 const static MCFixupKindInfo Infos[VE::NumTargetFixupKinds] = {
107 // name, offset, bits, flags
108 {.Name: "fixup_ve_reflong", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
109 {.Name: "fixup_ve_srel32", .TargetOffset: 0, .TargetSize: 32, .Flags: MCFixupKindInfo::FKF_IsPCRel},
110 {.Name: "fixup_ve_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
111 {.Name: "fixup_ve_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
112 {.Name: "fixup_ve_pc_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: MCFixupKindInfo::FKF_IsPCRel},
113 {.Name: "fixup_ve_pc_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: MCFixupKindInfo::FKF_IsPCRel},
114 {.Name: "fixup_ve_got_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
115 {.Name: "fixup_ve_got_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
116 {.Name: "fixup_ve_gotoff_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
117 {.Name: "fixup_ve_gotoff_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
118 {.Name: "fixup_ve_plt_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
119 {.Name: "fixup_ve_plt_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
120 {.Name: "fixup_ve_tls_gd_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
121 {.Name: "fixup_ve_tls_gd_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
122 {.Name: "fixup_ve_tpoff_hi32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
123 {.Name: "fixup_ve_tpoff_lo32", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
124 };
125
126 if (Kind < FirstTargetFixupKind)
127 return MCAsmBackend::getFixupKindInfo(Kind);
128
129 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
130 "Invalid kind!");
131 return Infos[Kind - FirstTargetFixupKind];
132 }
133
134 bool shouldForceRelocation(const MCAssembler &Asm, const MCFixup &Fixup,
135 const MCValue &Target,
136 const MCSubtargetInfo *STI) override {
137 switch ((VE::Fixups)Fixup.getKind()) {
138 default:
139 return false;
140 case VE::fixup_ve_tls_gd_hi32:
141 case VE::fixup_ve_tls_gd_lo32:
142 case VE::fixup_ve_tpoff_hi32:
143 case VE::fixup_ve_tpoff_lo32:
144 return true;
145 }
146 }
147
148 bool mayNeedRelaxation(const MCInst &Inst,
149 const MCSubtargetInfo &STI) const override {
150 // Not implemented yet. For example, if we have a branch with
151 // lager than SIMM32 immediate value, we want to relaxation such
152 // branch instructions.
153 return false;
154 }
155
156 /// fixupNeedsRelaxation - Target specific predicate for whether a given
157 /// fixup requires the associated instruction to be relaxed.
158 bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
159 const MCRelaxableFragment *DF,
160 const MCAsmLayout &Layout) const override {
161 // Not implemented yet. For example, if we have a branch with
162 // lager than SIMM32 immediate value, we want to relaxation such
163 // branch instructions.
164 return false;
165 }
166 void relaxInstruction(MCInst &Inst,
167 const MCSubtargetInfo &STI) const override {
168 // Aurora VE doesn't support relaxInstruction yet.
169 llvm_unreachable("relaxInstruction() should not be called");
170 }
171
172 bool writeNopData(raw_ostream &OS, uint64_t Count,
173 const MCSubtargetInfo *STI) const override {
174 if ((Count % 8) != 0)
175 return false;
176
177 for (uint64_t i = 0; i < Count; i += 8)
178 support::endian::write<uint64_t>(os&: OS, value: 0x7900000000000000ULL,
179 endian: llvm::endianness::little);
180
181 return true;
182 }
183};
184
185class ELFVEAsmBackend : public VEAsmBackend {
186 Triple::OSType OSType;
187
188public:
189 ELFVEAsmBackend(const Target &T, Triple::OSType OSType)
190 : VEAsmBackend(T), OSType(OSType) {}
191
192 void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
193 const MCValue &Target, MutableArrayRef<char> Data,
194 uint64_t Value, bool IsResolved,
195 const MCSubtargetInfo *STI) const override {
196 Value = adjustFixupValue(Kind: Fixup.getKind(), Value);
197 if (!Value)
198 return; // Doesn't change encoding.
199
200 MCFixupKindInfo Info = getFixupKindInfo(Kind: Fixup.getKind());
201
202 // Shift the value into position.
203 Value <<= Info.TargetOffset;
204
205 unsigned NumBytes = getFixupKindNumBytes(Kind: Fixup.getKind());
206 unsigned Offset = Fixup.getOffset();
207 assert(Offset + NumBytes <= Data.size() && "Invalid fixup offset!");
208 // For each byte of the fragment that the fixup touches, mask in the bits
209 // from the fixup value. The Value has been "split up" into the
210 // appropriate bitfields above.
211 for (unsigned i = 0; i != NumBytes; ++i) {
212 unsigned Idx =
213 Endian == llvm::endianness::little ? i : (NumBytes - 1) - i;
214 Data[Offset + Idx] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
215 }
216 }
217
218 std::unique_ptr<MCObjectTargetWriter>
219 createObjectTargetWriter() const override {
220 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(OSType);
221 return createVEELFObjectWriter(OSABI);
222 }
223};
224} // end anonymous namespace
225
226MCAsmBackend *llvm::createVEAsmBackend(const Target &T,
227 const MCSubtargetInfo &STI,
228 const MCRegisterInfo &MRI,
229 const MCTargetOptions &Options) {
230 return new ELFVEAsmBackend(T, STI.getTargetTriple().getOS());
231}
232

source code of llvm/lib/Target/VE/MCTargetDesc/VEAsmBackend.cpp