1 //===- lib/MC/MCSymbolELF.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 "llvm/MC/MCSymbolELF.h" 10 #include "llvm/BinaryFormat/ELF.h" 11 #include "llvm/MC/MCFixupKindInfo.h" 12 13 namespace llvm { 14 15 namespace { 16 enum { 17 // Shift value for STT_* flags. 7 possible values. 3 bits. 18 ELF_STT_Shift = 0, 19 20 // Shift value for STB_* flags. 4 possible values, 2 bits. 21 ELF_STB_Shift = 3, 22 23 // Shift value for STV_* flags. 4 possible values, 2 bits. 24 ELF_STV_Shift = 5, 25 26 // Shift value for STO_* flags. 3 bits. All the values are between 0x20 and 27 // 0xe0, so we shift right by 5 before storing. 28 ELF_STO_Shift = 7, 29 30 // One bit. 31 ELF_IsSignature_Shift = 10, 32 33 // One bit. 34 ELF_WeakrefUsedInReloc_Shift = 11, 35 36 // One bit. 37 ELF_BindingSet_Shift = 12 38 }; 39 } 40 41 void MCSymbolELF::setBinding(unsigned Binding) const { 42 setIsBindingSet(); 43 if (getType() == ELF::STT_SECTION && Binding != ELF::STB_LOCAL) 44 setType(ELF::STT_NOTYPE); 45 unsigned Val; 46 switch (Binding) { 47 default: 48 llvm_unreachable("Unsupported Binding"); 49 case ELF::STB_LOCAL: 50 Val = 0; 51 break; 52 case ELF::STB_GLOBAL: 53 Val = 1; 54 break; 55 case ELF::STB_WEAK: 56 Val = 2; 57 break; 58 case ELF::STB_GNU_UNIQUE: 59 Val = 3; 60 break; 61 } 62 uint32_t OtherFlags = getFlags() & ~(0x3 << ELF_STB_Shift); 63 setFlags(OtherFlags | (Val << ELF_STB_Shift)); 64 } 65 66 unsigned MCSymbolELF::getBinding() const { 67 if (isBindingSet()) { 68 uint32_t Val = (Flags >> ELF_STB_Shift) & 3; 69 switch (Val) { 70 default: 71 llvm_unreachable("Invalid value"); 72 case 0: 73 return ELF::STB_LOCAL; 74 case 1: 75 return ELF::STB_GLOBAL; 76 case 2: 77 return ELF::STB_WEAK; 78 case 3: 79 return ELF::STB_GNU_UNIQUE; 80 } 81 } 82 83 if (isDefined()) 84 return ELF::STB_LOCAL; 85 if (isUsedInReloc()) 86 return ELF::STB_GLOBAL; 87 if (isWeakrefUsedInReloc()) 88 return ELF::STB_WEAK; 89 if (isSignature()) 90 return ELF::STB_LOCAL; 91 return ELF::STB_GLOBAL; 92 } 93 94 void MCSymbolELF::setType(unsigned Type) const { 95 unsigned Val; 96 if (Type == ELF::STT_SECTION && getBinding() != ELF::STB_LOCAL) 97 return; 98 switch (Type) { 99 default: 100 llvm_unreachable("Unsupported Binding"); 101 case ELF::STT_NOTYPE: 102 Val = 0; 103 break; 104 case ELF::STT_OBJECT: 105 Val = 1; 106 break; 107 case ELF::STT_FUNC: 108 Val = 2; 109 break; 110 case ELF::STT_SECTION: 111 Val = 3; 112 break; 113 case ELF::STT_COMMON: 114 Val = 4; 115 break; 116 case ELF::STT_TLS: 117 Val = 5; 118 break; 119 case ELF::STT_GNU_IFUNC: 120 Val = 6; 121 break; 122 } 123 uint32_t OtherFlags = getFlags() & ~(0x7 << ELF_STT_Shift); 124 setFlags(OtherFlags | (Val << ELF_STT_Shift)); 125 } 126 127 unsigned MCSymbolELF::getType() const { 128 uint32_t Val = (Flags >> ELF_STT_Shift) & 7; 129 switch (Val) { 130 default: 131 llvm_unreachable("Invalid value"); 132 case 0: 133 return ELF::STT_NOTYPE; 134 case 1: 135 return ELF::STT_OBJECT; 136 case 2: 137 return ELF::STT_FUNC; 138 case 3: 139 return ELF::STT_SECTION; 140 case 4: 141 return ELF::STT_COMMON; 142 case 5: 143 return ELF::STT_TLS; 144 case 6: 145 return ELF::STT_GNU_IFUNC; 146 } 147 } 148 149 void MCSymbolELF::setVisibility(unsigned Visibility) { 150 assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL || 151 Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED); 152 153 uint32_t OtherFlags = getFlags() & ~(0x3 << ELF_STV_Shift); 154 setFlags(OtherFlags | (Visibility << ELF_STV_Shift)); 155 } 156 157 unsigned MCSymbolELF::getVisibility() const { 158 unsigned Visibility = (Flags >> ELF_STV_Shift) & 3; 159 return Visibility; 160 } 161 162 void MCSymbolELF::setOther(unsigned Other) { 163 assert((Other & 0x1f) == 0); 164 Other >>= 5; 165 assert(Other <= 0x7); 166 uint32_t OtherFlags = getFlags() & ~(0x7 << ELF_STO_Shift); 167 setFlags(OtherFlags | (Other << ELF_STO_Shift)); 168 } 169 170 unsigned MCSymbolELF::getOther() const { 171 unsigned Other = (Flags >> ELF_STO_Shift) & 7; 172 return Other << 5; 173 } 174 175 void MCSymbolELF::setIsWeakrefUsedInReloc() const { 176 uint32_t OtherFlags = getFlags() & ~(0x1 << ELF_WeakrefUsedInReloc_Shift); 177 setFlags(OtherFlags | (1 << ELF_WeakrefUsedInReloc_Shift)); 178 } 179 180 bool MCSymbolELF::isWeakrefUsedInReloc() const { 181 return getFlags() & (0x1 << ELF_WeakrefUsedInReloc_Shift); 182 } 183 184 void MCSymbolELF::setIsSignature() const { 185 uint32_t OtherFlags = getFlags() & ~(0x1 << ELF_IsSignature_Shift); 186 setFlags(OtherFlags | (1 << ELF_IsSignature_Shift)); 187 } 188 189 bool MCSymbolELF::isSignature() const { 190 return getFlags() & (0x1 << ELF_IsSignature_Shift); 191 } 192 193 void MCSymbolELF::setIsBindingSet() const { 194 uint32_t OtherFlags = getFlags() & ~(0x1 << ELF_BindingSet_Shift); 195 setFlags(OtherFlags | (1 << ELF_BindingSet_Shift)); 196 } 197 198 bool MCSymbolELF::isBindingSet() const { 199 return getFlags() & (0x1 << ELF_BindingSet_Shift); 200 } 201 } 202