blob: de3c36b353a37b4f665ecf5267f76057344df7fe [file] [log] [blame]
//===- Relocations.h -------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLD_ELF_RELOCATIONS_H
#define LLD_ELF_RELOCATIONS_H
#include "lld/Common/LLVM.h"
#include "llvm/ADT/DenseMap.h"
#include <map>
#include <vector>
namespace lld {
namespace elf {
class Symbol;
class InputSection;
class InputSectionBase;
class OutputSection;
class SectionBase;
// Represents a relocation type, such as R_X86_64_PC32 or R_ARM_THM_CALL.
using RelType = uint32_t;
using JumpModType = uint32_t;
// List of target-independent relocation types. Relocations read
// from files are converted to these types so that the main code
// doesn't have to know about architecture-specific details.
enum RelExpr {
R_ABS,
R_ADDEND,
R_DTPREL,
R_GOT,
R_GOT_OFF,
R_GOT_PC,
R_GOTONLY_PC,
R_GOTPLTONLY_PC,
R_GOTPLT,
R_GOTPLTREL,
R_GOTREL,
R_NONE,
R_PC,
R_PLT,
R_PLT_PC,
R_RELAX_GOT_PC,
R_RELAX_GOT_PC_NOPIC,
R_RELAX_TLS_GD_TO_IE,
R_RELAX_TLS_GD_TO_IE_ABS,
R_RELAX_TLS_GD_TO_IE_GOT_OFF,
R_RELAX_TLS_GD_TO_IE_GOTPLT,
R_RELAX_TLS_GD_TO_LE,
R_RELAX_TLS_GD_TO_LE_NEG,
R_RELAX_TLS_IE_TO_LE,
R_RELAX_TLS_LD_TO_LE,
R_RELAX_TLS_LD_TO_LE_ABS,
R_SIZE,
R_TPREL,
R_TPREL_NEG,
R_TLSDESC,
R_TLSDESC_CALL,
R_TLSDESC_PC,
R_TLSGD_GOT,
R_TLSGD_GOTPLT,
R_TLSGD_PC,
R_TLSIE_HINT,
R_TLSLD_GOT,
R_TLSLD_GOTPLT,
R_TLSLD_GOT_OFF,
R_TLSLD_HINT,
R_TLSLD_PC,
// The following is abstract relocation types used for only one target.
//
// Even though RelExpr is intended to be a target-neutral representation
// of a relocation type, there are some relocations whose semantics are
// unique to a target. Such relocation are marked with R_<TARGET_NAME>.
R_AARCH64_GOT_PAGE_PC,
R_AARCH64_PAGE_PC,
R_AARCH64_RELAX_TLS_GD_TO_IE_PAGE_PC,
R_AARCH64_TLSDESC_PAGE,
R_ARM_PCA,
R_ARM_SBREL,
R_MIPS_GOTREL,
R_MIPS_GOT_GP,
R_MIPS_GOT_GP_PC,
R_MIPS_GOT_LOCAL_PAGE,
R_MIPS_GOT_OFF,
R_MIPS_GOT_OFF32,
R_MIPS_TLSGD,
R_MIPS_TLSLD,
R_PPC32_PLTREL,
R_PPC64_CALL,
R_PPC64_CALL_PLT,
R_PPC64_RELAX_TOC,
R_PPC64_TOCBASE,
R_PPC64_RELAX_GOT_PC,
R_RISCV_ADD,
R_RISCV_PC_INDIRECT,
};
// Architecture-neutral representation of relocation.
struct Relocation {
RelExpr expr;
RelType type;
uint64_t offset;
int64_t addend;
Symbol *sym;
};
// Manipulate jump instructions with these modifiers. These are used to relax
// jump instruction opcodes at basic block boundaries and are particularly
// useful when basic block sections are enabled.
struct JumpInstrMod {
JumpModType original;
uint64_t offset;
unsigned size;
};
// This function writes undefined symbol diagnostics to an internal buffer.
// Call reportUndefinedSymbols() after calling scanRelocations() to emit
// the diagnostics.
template <class ELFT> void scanRelocations(InputSectionBase &);
template <class ELFT> void reportUndefinedSymbols();
void hexagonTLSSymbolUpdate(ArrayRef<OutputSection *> outputSections);
bool hexagonNeedsTLSSymbol(ArrayRef<OutputSection *> outputSections);
class ThunkSection;
class Thunk;
class InputSectionDescription;
class ThunkCreator {
public:
// Return true if Thunks have been added to OutputSections
bool createThunks(ArrayRef<OutputSection *> outputSections);
// The number of completed passes of createThunks this permits us
// to do one time initialization on Pass 0 and put a limit on the
// number of times it can be called to prevent infinite loops.
uint32_t pass = 0;
private:
void mergeThunks(ArrayRef<OutputSection *> outputSections);
ThunkSection *getISDThunkSec(OutputSection *os, InputSection *isec,
InputSectionDescription *isd, uint32_t type,
uint64_t src);
ThunkSection *getISThunkSec(InputSection *isec);
void createInitialThunkSections(ArrayRef<OutputSection *> outputSections);
std::pair<Thunk *, bool> getThunk(InputSection *isec, Relocation &rel,
uint64_t src);
ThunkSection *addThunkSection(OutputSection *os, InputSectionDescription *,
uint64_t off);
bool normalizeExistingThunk(Relocation &rel, uint64_t src);
// Record all the available Thunks for a (Symbol, addend) pair, where Symbol
// is represented as a (section, offset) pair. There may be multiple
// relocations sharing the same (section, offset + addend) pair. We may revert
// a relocation back to its original non-Thunk target, and restore the
// original addend, so we cannot fold offset + addend. A nested pair is used
// because DenseMapInfo is not specialized for std::tuple.
llvm::DenseMap<std::pair<std::pair<SectionBase *, uint64_t>, int64_t>,
std::vector<Thunk *>>
thunkedSymbolsBySectionAndAddend;
llvm::DenseMap<std::pair<Symbol *, int64_t>, std::vector<Thunk *>>
thunkedSymbols;
// Find a Thunk from the Thunks symbol definition, we can use this to find
// the Thunk from a relocation to the Thunks symbol definition.
llvm::DenseMap<Symbol *, Thunk *> thunks;
// Track InputSections that have an inline ThunkSection placed in front
// an inline ThunkSection may have control fall through to the section below
// so we need to make sure that there is only one of them.
// The Mips LA25 Thunk is an example of an inline ThunkSection.
llvm::DenseMap<InputSection *, ThunkSection *> thunkedSections;
};
// Return a int64_t to make sure we get the sign extension out of the way as
// early as possible.
template <class ELFT>
static inline int64_t getAddend(const typename ELFT::Rel &rel) {
return 0;
}
template <class ELFT>
static inline int64_t getAddend(const typename ELFT::Rela &rel) {
return rel.r_addend;
}
} // namespace elf
} // namespace lld
#endif