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
21 using namespace llvm;
22
adjustFixupValue(unsigned Kind,uint64_t Value)23 static 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.
getFixupKindNumBytes(unsigned Kind)58 static 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
94 namespace {
95 class VEAsmBackend : public MCAsmBackend {
96 protected:
97 const Target &TheTarget;
98
99 public:
VEAsmBackend(const Target & T)100 VEAsmBackend(const Target &T)
101 : MCAsmBackend(llvm::endianness::little), TheTarget(T) {}
102
getNumFixupKinds() const103 unsigned getNumFixupKinds() const override { return VE::NumTargetFixupKinds; }
104
getFixupKindInfo(MCFixupKind Kind) const105 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override {
106 const static MCFixupKindInfo Infos[VE::NumTargetFixupKinds] = {
107 // name, offset, bits, flags
108 {"fixup_ve_reflong", 0, 32, 0},
109 {"fixup_ve_srel32", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
110 {"fixup_ve_hi32", 0, 32, 0},
111 {"fixup_ve_lo32", 0, 32, 0},
112 {"fixup_ve_pc_hi32", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
113 {"fixup_ve_pc_lo32", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
114 {"fixup_ve_got_hi32", 0, 32, 0},
115 {"fixup_ve_got_lo32", 0, 32, 0},
116 {"fixup_ve_gotoff_hi32", 0, 32, 0},
117 {"fixup_ve_gotoff_lo32", 0, 32, 0},
118 {"fixup_ve_plt_hi32", 0, 32, 0},
119 {"fixup_ve_plt_lo32", 0, 32, 0},
120 {"fixup_ve_tls_gd_hi32", 0, 32, 0},
121 {"fixup_ve_tls_gd_lo32", 0, 32, 0},
122 {"fixup_ve_tpoff_hi32", 0, 32, 0},
123 {"fixup_ve_tpoff_lo32", 0, 32, 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
shouldForceRelocation(const MCAssembler & Asm,const MCFixup & Fixup,const MCValue & Target,const MCSubtargetInfo * STI)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
mayNeedRelaxation(const MCInst & Inst,const MCSubtargetInfo & STI) const148 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
relaxInstruction(MCInst & Inst,const MCSubtargetInfo & STI) const156 void relaxInstruction(MCInst &Inst,
157 const MCSubtargetInfo &STI) const override {
158 // Aurora VE doesn't support relaxInstruction yet.
159 llvm_unreachable("relaxInstruction() should not be called");
160 }
161
writeNopData(raw_ostream & OS,uint64_t Count,const MCSubtargetInfo * STI) const162 bool writeNopData(raw_ostream &OS, uint64_t Count,
163 const MCSubtargetInfo *STI) const override {
164 if ((Count % 8) != 0)
165 return false;
166
167 for (uint64_t i = 0; i < Count; i += 8)
168 support::endian::write<uint64_t>(OS, 0x7900000000000000ULL,
169 llvm::endianness::little);
170
171 return true;
172 }
173 };
174
175 class ELFVEAsmBackend : public VEAsmBackend {
176 Triple::OSType OSType;
177
178 public:
ELFVEAsmBackend(const Target & T,Triple::OSType OSType)179 ELFVEAsmBackend(const Target &T, Triple::OSType OSType)
180 : VEAsmBackend(T), OSType(OSType) {}
181
applyFixup(const MCAssembler & Asm,const MCFixup & Fixup,const MCValue & Target,MutableArrayRef<char> Data,uint64_t Value,bool IsResolved,const MCSubtargetInfo * STI) const182 void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
183 const MCValue &Target, MutableArrayRef<char> Data,
184 uint64_t Value, bool IsResolved,
185 const MCSubtargetInfo *STI) const override {
186 Value = adjustFixupValue(Fixup.getKind(), Value);
187 if (!Value)
188 return; // Doesn't change encoding.
189
190 MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
191
192 // Shift the value into position.
193 Value <<= Info.TargetOffset;
194
195 unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
196 unsigned Offset = Fixup.getOffset();
197 assert(Offset + NumBytes <= Data.size() && "Invalid fixup offset!");
198 // For each byte of the fragment that the fixup touches, mask in the bits
199 // from the fixup value. The Value has been "split up" into the
200 // appropriate bitfields above.
201 for (unsigned i = 0; i != NumBytes; ++i) {
202 unsigned Idx =
203 Endian == llvm::endianness::little ? i : (NumBytes - 1) - i;
204 Data[Offset + Idx] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
205 }
206 }
207
208 std::unique_ptr<MCObjectTargetWriter>
createObjectTargetWriter() const209 createObjectTargetWriter() const override {
210 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(OSType);
211 return createVEELFObjectWriter(OSABI);
212 }
213 };
214 } // end anonymous namespace
215
createVEAsmBackend(const Target & T,const MCSubtargetInfo & STI,const MCRegisterInfo & MRI,const MCTargetOptions & Options)216 MCAsmBackend *llvm::createVEAsmBackend(const Target &T,
217 const MCSubtargetInfo &STI,
218 const MCRegisterInfo &MRI,
219 const MCTargetOptions &Options) {
220 return new ELFVEAsmBackend(T, STI.getTargetTriple().getOS());
221 }
222