1// Derived from Inferno utils/6l/l.h and related files. 2// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/l.h 3// 4// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. 5// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) 6// Portions Copyright © 1997-1999 Vita Nuova Limited 7// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) 8// Portions Copyright © 2004,2006 Bruce Ellis 9// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) 10// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others 11// Portions Copyright © 2009 The Go Authors. All rights reserved. 12// 13// Permission is hereby granted, free of charge, to any person obtaining a copy 14// of this software and associated documentation files (the "Software"), to deal 15// in the Software without restriction, including without limitation the rights 16// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 17// copies of the Software, and to permit persons to whom the Software is 18// furnished to do so, subject to the following conditions: 19// 20// The above copyright notice and this permission notice shall be included in 21// all copies or substantial portions of the Software. 22// 23// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 24// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 25// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 26// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 27// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 28// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 29// THE SOFTWARE. 30 31package objabi 32 33type RelocType int32 34 35//go:generate stringer -type=RelocType 36const ( 37 R_ADDR RelocType = 1 + iota 38 // R_ADDRPOWER relocates a pair of "D-form" instructions (instructions with 16-bit 39 // immediates in the low half of the instruction word), usually addis followed by 40 // another add or a load, inserting the "high adjusted" 16 bits of the address of 41 // the referenced symbol into the immediate field of the first instruction and the 42 // low 16 bits into that of the second instruction. 43 R_ADDRPOWER 44 // R_ADDRARM64 relocates an adrp, add pair to compute the address of the 45 // referenced symbol. 46 R_ADDRARM64 47 // R_ADDRMIPS (only used on mips/mips64) resolves to the low 16 bits of an external 48 // address, by encoding it into the instruction. 49 R_ADDRMIPS 50 // R_ADDROFF resolves to a 32-bit offset from the beginning of the section 51 // holding the data being relocated to the referenced symbol. 52 R_ADDROFF 53 // R_WEAKADDROFF resolves just like R_ADDROFF but is a weak relocation. 54 // A weak relocation does not make the symbol it refers to reachable, 55 // and is only honored by the linker if the symbol is in some other way 56 // reachable. 57 R_WEAKADDROFF 58 R_SIZE 59 R_CALL 60 R_CALLARM 61 R_CALLARM64 62 R_CALLIND 63 R_CALLPOWER 64 // R_CALLMIPS (only used on mips64) resolves to non-PC-relative target address 65 // of a CALL (JAL) instruction, by encoding the address into the instruction. 66 R_CALLMIPS 67 R_CONST 68 R_PCREL 69 // R_TLS_LE, used on 386, amd64, and ARM, resolves to the offset of the 70 // thread-local symbol from the thread local base and is used to implement the 71 // "local exec" model for tls access (r.Sym is not set on intel platforms but is 72 // set to a TLS symbol -- runtime.tlsg -- in the linker when externally linking). 73 R_TLS_LE 74 // R_TLS_IE, used 386, amd64, and ARM resolves to the PC-relative offset to a GOT 75 // slot containing the offset from the thread-local symbol from the thread local 76 // base and is used to implemented the "initial exec" model for tls access (r.Sym 77 // is not set on intel platforms but is set to a TLS symbol -- runtime.tlsg -- in 78 // the linker when externally linking). 79 R_TLS_IE 80 R_GOTOFF 81 R_PLT0 82 R_PLT1 83 R_PLT2 84 R_USEFIELD 85 // R_USETYPE resolves to an *rtype, but no relocation is created. The 86 // linker uses this as a signal that the pointed-to type information 87 // should be linked into the final binary, even if there are no other 88 // direct references. (This is used for types reachable by reflection.) 89 R_USETYPE 90 // R_METHODOFF resolves to a 32-bit offset from the beginning of the section 91 // holding the data being relocated to the referenced symbol. 92 // It is a variant of R_ADDROFF used when linking from the uncommonType of a 93 // *rtype, and may be set to zero by the linker if it determines the method 94 // text is unreachable by the linked program. 95 R_METHODOFF 96 R_POWER_TOC 97 R_GOTPCREL 98 // R_JMPMIPS (only used on mips64) resolves to non-PC-relative target address 99 // of a JMP instruction, by encoding the address into the instruction. 100 // The stack nosplit check ignores this since it is not a function call. 101 R_JMPMIPS 102 103 // R_DWARFSECREF resolves to the offset of the symbol from its section. 104 // Target of relocation must be size 4 (in current implementation). 105 R_DWARFSECREF 106 107 // R_DWARFFILEREF resolves to an index into the DWARF .debug_line 108 // file table for the specified file symbol. Must be applied to an 109 // attribute of form DW_FORM_data4. 110 R_DWARFFILEREF 111 112 // Platform dependent relocations. Architectures with fixed width instructions 113 // have the inherent issue that a 32-bit (or 64-bit!) displacement cannot be 114 // stuffed into a 32-bit instruction, so an address needs to be spread across 115 // several instructions, and in turn this requires a sequence of relocations, each 116 // updating a part of an instruction. This leads to relocation codes that are 117 // inherently processor specific. 118 119 // Arm64. 120 121 // Set a MOV[NZ] immediate field to bits [15:0] of the offset from the thread 122 // local base to the thread local variable defined by the referenced (thread 123 // local) symbol. Error if the offset does not fit into 16 bits. 124 R_ARM64_TLS_LE 125 126 // Relocates an ADRP; LD64 instruction sequence to load the offset between 127 // the thread local base and the thread local variable defined by the 128 // referenced (thread local) symbol from the GOT. 129 R_ARM64_TLS_IE 130 131 // R_ARM64_GOTPCREL relocates an adrp, ld64 pair to compute the address of the GOT 132 // slot of the referenced symbol. 133 R_ARM64_GOTPCREL 134 135 // PPC64. 136 137 // R_POWER_TLS_LE is used to implement the "local exec" model for tls 138 // access. It resolves to the offset of the thread-local symbol from the 139 // thread pointer (R13) and inserts this value into the low 16 bits of an 140 // instruction word. 141 R_POWER_TLS_LE 142 143 // R_POWER_TLS_IE is used to implement the "initial exec" model for tls access. It 144 // relocates a D-form, DS-form instruction sequence like R_ADDRPOWER_DS. It 145 // inserts to the offset of GOT slot for the thread-local symbol from the TOC (the 146 // GOT slot is filled by the dynamic linker with the offset of the thread-local 147 // symbol from the thread pointer (R13)). 148 R_POWER_TLS_IE 149 150 // R_POWER_TLS marks an X-form instruction such as "MOVD 0(R13)(R31*1), g" as 151 // accessing a particular thread-local symbol. It does not affect code generation 152 // but is used by the system linker when relaxing "initial exec" model code to 153 // "local exec" model code. 154 R_POWER_TLS 155 156 // R_ADDRPOWER_DS is similar to R_ADDRPOWER above, but assumes the second 157 // instruction is a "DS-form" instruction, which has an immediate field occupying 158 // bits [15:2] of the instruction word. Bits [15:2] of the address of the 159 // relocated symbol are inserted into this field; it is an error if the last two 160 // bits of the address are not 0. 161 R_ADDRPOWER_DS 162 163 // R_ADDRPOWER_PCREL relocates a D-form, DS-form instruction sequence like 164 // R_ADDRPOWER_DS but inserts the offset of the GOT slot for the referenced symbol 165 // from the TOC rather than the symbol's address. 166 R_ADDRPOWER_GOT 167 168 // R_ADDRPOWER_PCREL relocates two D-form instructions like R_ADDRPOWER, but 169 // inserts the displacement from the place being relocated to the address of the 170 // the relocated symbol instead of just its address. 171 R_ADDRPOWER_PCREL 172 173 // R_ADDRPOWER_TOCREL relocates two D-form instructions like R_ADDRPOWER, but 174 // inserts the offset from the TOC to the address of the relocated symbol 175 // rather than the symbol's address. 176 R_ADDRPOWER_TOCREL 177 178 // R_ADDRPOWER_TOCREL relocates a D-form, DS-form instruction sequence like 179 // R_ADDRPOWER_DS but inserts the offset from the TOC to the address of the the 180 // relocated symbol rather than the symbol's address. 181 R_ADDRPOWER_TOCREL_DS 182 183 // R_PCRELDBL relocates s390x 2-byte aligned PC-relative addresses. 184 // TODO(mundaym): remove once variants can be serialized - see issue 14218. 185 R_PCRELDBL 186 187 // R_ADDRMIPSU (only used on mips/mips64) resolves to the sign-adjusted "upper" 16 188 // bits (bit 16-31) of an external address, by encoding it into the instruction. 189 R_ADDRMIPSU 190 // R_ADDRMIPSTLS (only used on mips64) resolves to the low 16 bits of a TLS 191 // address (offset from thread pointer), by encoding it into the instruction. 192 R_ADDRMIPSTLS 193 // R_ADDRCUOFF resolves to a pointer-sized offset from the start of the 194 // symbol's DWARF compile unit. 195 R_ADDRCUOFF 196) 197 198// IsDirectJump returns whether r is a relocation for a direct jump. 199// A direct jump is a CALL or JMP instruction that takes the target address 200// as immediate. The address is embedded into the instruction, possibly 201// with limited width. 202// An indirect jump is a CALL or JMP instruction that takes the target address 203// in register or memory. 204func (r RelocType) IsDirectJump() bool { 205 switch r { 206 case R_CALL, R_CALLARM, R_CALLARM64, R_CALLPOWER, R_CALLMIPS, R_JMPMIPS: 207 return true 208 } 209 return false 210} 211