0f7cedaa1e
We will need to do something like this to support range extension thunks since that process is iterative. Doing this also has the advantage that when doing the regular relocation scan the offset in the output section is known and we can just store that. This reduces the number of times we have to run getOffset and I think will allow a more specialized .eh_frame representation. By itself this is already a performance win. firefox master 7.295045737 patch 7.209466989 0.98826892235 chromium master 4.531254468 patch 4.509221804 0.995137623774 chromium fast master 1.836928973 patch 1.823805241 0.992855612714 the gold plugin master 0.379768791 patch 0.380043405 1.00072310839 clang master 0.642698284 patch 0.642215663 0.999249070657 llvm-as master 0.036665467 patch 0.036456225 0.994293213284 the gold plugin fsds master 0.40395817 patch 0.404384555 1.0010555177 clang fsds master 0.722045545 patch 0.720946135 0.998477367518 llvm-as fsds master 0.03292646 patch 0.032759965 0.994943428477 scylla master 3.427376378 patch 3.368316181 0.98276810292 llvm-svn: 276146
117 lines
4.2 KiB
C++
117 lines
4.2 KiB
C++
//===- Target.h -------------------------------------------------*- C++ -*-===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLD_ELF_TARGET_H
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#define LLD_ELF_TARGET_H
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#include "InputSection.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Object/ELF.h"
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#include <memory>
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namespace lld {
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namespace elf {
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class InputFile;
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class SymbolBody;
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class TargetInfo {
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public:
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virtual bool isTlsInitialExecRel(uint32_t Type) const;
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virtual bool isTlsLocalDynamicRel(uint32_t Type) const;
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virtual bool isTlsGlobalDynamicRel(uint32_t Type) const;
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virtual uint32_t getDynRel(uint32_t Type) const { return Type; }
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virtual void writeGotPltHeader(uint8_t *Buf) const {}
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virtual void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const {};
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virtual uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const;
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// If lazy binding is supported, the first entry of the PLT has code
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// to call the dynamic linker to resolve PLT entries the first time
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// they are called. This function writes that code.
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virtual void writePltHeader(uint8_t *Buf) const {}
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virtual void writePlt(uint8_t *Buf, uint64_t GotEntryAddr,
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uint64_t PltEntryAddr, int32_t Index,
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unsigned RelOff) const {}
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// Returns true if a relocation only uses the low bits of a value such that
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// all those bits are in in the same page. For example, if the relocation
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// only uses the low 12 bits in a system with 4k pages. If this is true, the
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// bits will always have the same value at runtime and we don't have to emit
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// a dynamic relocation.
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virtual bool usesOnlyLowPageBits(uint32_t Type) const;
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// Decide whether a Thunk is needed for the relocation from File
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// targeting S. Returns one of:
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// Expr if there is no Thunk required
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// R_THUNK_ABS if thunk is required and expression is absolute
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// R_THUNK_PC if thunk is required and expression is pc rel
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// R_THUNK_PLT_PC if thunk is required to PLT entry and expression is pc rel
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virtual RelExpr getThunkExpr(RelExpr Expr, uint32_t RelocType,
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const InputFile &File,
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const SymbolBody &S) const;
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virtual RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const = 0;
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virtual void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const = 0;
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virtual ~TargetInfo();
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unsigned TlsGdRelaxSkip = 1;
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unsigned PageSize = 4096;
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// On freebsd x86_64 the first page cannot be mmaped.
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// On linux that is controled by vm.mmap_min_addr. At least on some x86_64
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// installs that is 65536, so the first 15 pages cannot be used.
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// Given that, the smallest value that can be used in here is 0x10000.
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// If using 2MB pages, the smallest page aligned address that works is
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// 0x200000, but it looks like every OS uses 4k pages for executables.
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uint64_t DefaultImageBase = 0x10000;
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uint32_t CopyRel;
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uint32_t GotRel;
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uint32_t PltRel;
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uint32_t RelativeRel;
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uint32_t IRelativeRel;
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uint32_t TlsDescRel;
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uint32_t TlsGotRel;
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uint32_t TlsModuleIndexRel;
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uint32_t TlsOffsetRel;
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unsigned GotEntrySize;
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unsigned GotPltEntrySize;
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unsigned PltEntrySize;
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unsigned PltHeaderSize;
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// At least on x86_64 positions 1 and 2 are used by the first plt entry
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// to support lazy loading.
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unsigned GotPltHeaderEntriesNum = 3;
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// Set to 0 for variant 2
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unsigned TcbSize = 0;
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bool NeedsThunks = false;
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virtual RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
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RelExpr Expr) const;
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virtual void relaxGot(uint8_t *Loc, uint64_t Val) const;
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virtual void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
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virtual void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
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virtual void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
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virtual void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
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};
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StringRef getRelName(uint32_t Type);
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uint64_t getPPC64TocBase();
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const unsigned MipsGPOffset = 0x7ff0;
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extern TargetInfo *Target;
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TargetInfo *createTarget();
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}
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}
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#endif
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