1 //===- Relocations.h -------------------------------------------*- C++ -*-===//
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
7 //===----------------------------------------------------------------------===//
9 #ifndef LLD_ELF_RELOCATIONS_H
10 #define LLD_ELF_RELOCATIONS_H
12 #include "lld/Common/LLVM.h"
13 #include "llvm/ADT/DenseMap.h"
21 class InputSectionBase;
25 // Represents a relocation type, such as R_X86_64_PC32 or R_ARM_THM_CALL.
26 using RelType = uint32_t;
28 // List of target-independent relocation types. Relocations read
29 // from files are converted to these types so that the main code
30 // doesn't have to know about architecture-specific details.
52 R_RELAX_TLS_GD_TO_IE_ABS,
53 R_RELAX_TLS_GD_TO_IE_GOT_OFF,
54 R_RELAX_TLS_GD_TO_IE_GOTPLT,
56 R_RELAX_TLS_GD_TO_LE_NEG,
59 R_RELAX_TLS_LD_TO_LE_ABS,
75 // The following is abstract relocation types used for only one target.
77 // Even though RelExpr is intended to be a target-neutral representation
78 // of a relocation type, there are some relocations whose semantics are
79 // unique to a target. Such relocation are marked with R_<TARGET_NAME>.
80 R_AARCH64_GOT_PAGE_PC,
82 R_AARCH64_RELAX_TLS_GD_TO_IE_PAGE_PC,
83 R_AARCH64_TLSDESC_PAGE,
89 R_MIPS_GOT_LOCAL_PAGE,
103 // Architecture-neutral representation of relocation.
112 // This function writes undefined symbol diagnostics to an internal buffer.
113 // Call reportUndefinedSymbols() after calling scanRelocations() to emit
115 template <class ELFT> void scanRelocations(InputSectionBase &);
117 template <class ELFT> void reportUndefinedSymbols();
119 void addIRelativeRelocs();
123 struct InputSectionDescription;
127 // Return true if Thunks have been added to OutputSections
128 bool createThunks(ArrayRef<OutputSection *> outputSections);
130 // The number of completed passes of createThunks this permits us
131 // to do one time initialization on Pass 0 and put a limit on the
132 // number of times it can be called to prevent infinite loops.
136 void mergeThunks(ArrayRef<OutputSection *> outputSections);
138 ThunkSection *getISDThunkSec(OutputSection *os, InputSection *isec,
139 InputSectionDescription *isd, uint32_t type,
142 ThunkSection *getISThunkSec(InputSection *isec);
144 void createInitialThunkSections(ArrayRef<OutputSection *> outputSections);
146 std::pair<Thunk *, bool> getThunk(InputSection *isec, Relocation &rel,
149 ThunkSection *addThunkSection(OutputSection *os, InputSectionDescription *,
152 bool normalizeExistingThunk(Relocation &rel, uint64_t src);
154 // Record all the available Thunks for a Symbol
155 llvm::DenseMap<std::pair<SectionBase *, uint64_t>, std::vector<Thunk *>>
156 thunkedSymbolsBySection;
157 llvm::DenseMap<Symbol *, std::vector<Thunk *>> thunkedSymbols;
159 // Find a Thunk from the Thunks symbol definition, we can use this to find
160 // the Thunk from a relocation to the Thunks symbol definition.
161 llvm::DenseMap<Symbol *, Thunk *> thunks;
163 // Track InputSections that have an inline ThunkSection placed in front
164 // an inline ThunkSection may have control fall through to the section below
165 // so we need to make sure that there is only one of them.
166 // The Mips LA25 Thunk is an example of an inline ThunkSection.
167 llvm::DenseMap<InputSection *, ThunkSection *> thunkedSections;
170 // Return a int64_t to make sure we get the sign extension out of the way as
171 // early as possible.
172 template <class ELFT>
173 static inline int64_t getAddend(const typename ELFT::Rel &rel) {
176 template <class ELFT>
177 static inline int64_t getAddend(const typename ELFT::Rela &rel) {