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
20 using namespace llvm;
21
adjustFixupValue(unsigned Kind,uint64_t Value)22 static 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.
getFixupKindNumBytes(unsigned Kind)53 static 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
84 namespace {
85 class VEAsmBackend : public MCAsmBackend {
86 protected:
87 const Target &TheTarget;
88
89 public:
VEAsmBackend(const Target & T)90 VEAsmBackend(const Target &T)
91 : MCAsmBackend(llvm::endianness::little), TheTarget(T) {}
92
getFixupKindInfo(MCFixupKind Kind) const93 MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override {
94 const static MCFixupKindInfo Infos[VE::NumTargetFixupKinds] = {
95 // name, offset, bits, flags
96 {"fixup_ve_reflong", 0, 32, 0}, {"fixup_ve_srel32", 0, 32, 0},
97 {"fixup_ve_hi32", 0, 32, 0}, {"fixup_ve_lo32", 0, 32, 0},
98 {"fixup_ve_pc_hi32", 0, 32, 0}, {"fixup_ve_pc_lo32", 0, 32, 0},
99 {"fixup_ve_got_hi32", 0, 32, 0}, {"fixup_ve_got_lo32", 0, 32, 0},
100 {"fixup_ve_gotoff_hi32", 0, 32, 0}, {"fixup_ve_gotoff_lo32", 0, 32, 0},
101 {"fixup_ve_plt_hi32", 0, 32, 0}, {"fixup_ve_plt_lo32", 0, 32, 0},
102 {"fixup_ve_tls_gd_hi32", 0, 32, 0}, {"fixup_ve_tls_gd_lo32", 0, 32, 0},
103 {"fixup_ve_tpoff_hi32", 0, 32, 0}, {"fixup_ve_tpoff_lo32", 0, 32, 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 MutableArrayRef<char>, uint64_t Value,
116 bool IsResolved) override;
117
mayNeedRelaxation(unsigned Opcode,ArrayRef<MCOperand> Operands,const MCSubtargetInfo & STI) const118 bool mayNeedRelaxation(unsigned Opcode, ArrayRef<MCOperand> Operands,
119 const MCSubtargetInfo &STI) const override {
120 // Not implemented yet. For example, if we have a branch with
121 // lager than SIMM32 immediate value, we want to relaxation such
122 // branch instructions.
123 return false;
124 }
125
writeNopData(raw_ostream & OS,uint64_t Count,const MCSubtargetInfo * STI) const126 bool writeNopData(raw_ostream &OS, uint64_t Count,
127 const MCSubtargetInfo *STI) const override {
128 if ((Count % 8) != 0)
129 return false;
130
131 for (uint64_t i = 0; i < Count; i += 8)
132 support::endian::write<uint64_t>(OS, 0x7900000000000000ULL,
133 llvm::endianness::little);
134
135 return true;
136 }
137 };
138
139 class ELFVEAsmBackend : public VEAsmBackend {
140 Triple::OSType OSType;
141
142 public:
ELFVEAsmBackend(const Target & T,Triple::OSType OSType)143 ELFVEAsmBackend(const Target &T, Triple::OSType OSType)
144 : VEAsmBackend(T), OSType(OSType) {}
145
146 std::unique_ptr<MCObjectTargetWriter>
createObjectTargetWriter() const147 createObjectTargetWriter() const override {
148 uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(OSType);
149 return createVEELFObjectWriter(OSABI);
150 }
151 };
152 } // end anonymous namespace
153
applyFixup(const MCFragment & F,const MCFixup & Fixup,const MCValue & Target,MutableArrayRef<char> Data,uint64_t Value,bool IsResolved)154 void VEAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
155 const MCValue &Target, MutableArrayRef<char> Data,
156 uint64_t Value, bool IsResolved) {
157 switch (Fixup.getKind()) {
158 case VE::fixup_ve_tls_gd_hi32:
159 case VE::fixup_ve_tls_gd_lo32:
160 case VE::fixup_ve_tpoff_hi32:
161 case VE::fixup_ve_tpoff_lo32:
162 IsResolved = false;
163 break;
164 }
165 maybeAddReloc(F, Fixup, Target, Value, IsResolved);
166 Value = adjustFixupValue(Fixup.getKind(), Value);
167 if (!Value)
168 return; // Doesn't change encoding.
169
170 MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
171
172 // Shift the value into position.
173 Value <<= Info.TargetOffset;
174
175 unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
176 unsigned Offset = Fixup.getOffset();
177 assert(Offset + NumBytes <= Data.size() && "Invalid fixup offset!");
178 // For each byte of the fragment that the fixup touches, mask in the bits
179 // from the fixup value. The Value has been "split up" into the
180 // appropriate bitfields above.
181 for (unsigned i = 0; i != NumBytes; ++i) {
182 unsigned Idx = Endian == llvm::endianness::little ? i : (NumBytes - 1) - i;
183 Data[Offset + Idx] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
184 }
185 }
186
createVEAsmBackend(const Target & T,const MCSubtargetInfo & STI,const MCRegisterInfo & MRI,const MCTargetOptions & Options)187 MCAsmBackend *llvm::createVEAsmBackend(const Target &T,
188 const MCSubtargetInfo &STI,
189 const MCRegisterInfo &MRI,
190 const MCTargetOptions &Options) {
191 return new ELFVEAsmBackend(T, STI.getTargetTriple().getOS());
192 }
193