InputSection.h | Explore in Territory

//===- InputSection.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_MACHO_INPUT_SECTION_H
#define LLD_MACHO_INPUT_SECTION_H

#include "Config.h"
#include "Relocations.h"
#include "Symbols.h"

#include "lld/Common/LLVM.h"
#include "lld/Common/Memory.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/CachedHashString.h"
#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/BinaryFormat/MachO.h"

namespace lld {
namespace macho {

class InputFile;
class OutputSection;

class InputSection { … };

// ConcatInputSections are combined into (Concat)OutputSections through simple
// concatenation, in contrast with literal sections which may have their
// contents merged before output.
class ConcatInputSection final : public InputSection { … };

// Initialize a fake InputSection that does not belong to any InputFile.
// The created ConcatInputSection will always have 'live=true'
ConcatInputSection *makeSyntheticInputSection(StringRef segName,
                                              StringRef sectName,
                                              uint32_t flags = 0,
                                              ArrayRef<uint8_t> data = { … };

// Helper functions to make it easy to sprinkle asserts.

inline bool shouldOmitFromOutput(InputSection *isec) { … }

inline bool isCoalescedWeak(InputSection *isec) { … }

// We allocate a lot of these and binary search on them, so they should be as
// compact as possible. Hence the use of 31 rather than 64 bits for the hash.
struct StringPiece { … };

static_assert …;

// CStringInputSections are composed of multiple null-terminated string
// literals, which we represent using StringPieces. These literals can be
// deduplicated and tail-merged, so translating offsets between the input and
// outputs sections is more complicated.
//
// NOTE: One significant difference between LLD and ld64 is that we merge all
// cstring literals, even those referenced directly by non-private symbols.
// ld64 is more conservative and does not do that. This was mostly done for
// implementation simplicity; if we find programs that need the more
// conservative behavior we can certainly implement that.
class CStringInputSection final : public InputSection { … };

class WordLiteralInputSection final : public InputSection { … };

inline uint8_t sectionType(uint32_t flags) { … }

inline bool isZeroFill(uint32_t flags) { … }

inline bool isThreadLocalVariables(uint32_t flags) { … }

// These sections contain the data for initializing thread-local variables.
inline bool isThreadLocalData(uint32_t flags) { … }

inline bool isDebugSection(uint32_t flags) { … }

inline bool isWordLiteralSection(uint32_t flags) { … }

bool isCodeSection(const InputSection *);
bool isCfStringSection(const InputSection *);
bool isClassRefsSection(const InputSection *);
bool isSelRefsSection(const InputSection *);
bool isEhFrameSection(const InputSection *);
bool isGccExceptTabSection(const InputSection *);

extern std::vector<ConcatInputSection *> inputSections;
// This is used as a counter for specyfing input order for input sections
extern int inputSectionsOrder;

namespace section_names {

constexpr const char authGot[] = …;
constexpr const char authPtr[] = …;
constexpr const char binding[] = …;
constexpr const char bitcodeBundle[] = …;
constexpr const char cString[] = …;
constexpr const char cfString[] = …;
constexpr const char cgProfile[] = …;
constexpr const char chainFixups[] = …;
constexpr const char codeSignature[] = …;
constexpr const char common[] = …;
constexpr const char compactUnwind[] = …;
constexpr const char data[] = …;
constexpr const char debugAbbrev[] = …;
constexpr const char debugInfo[] = …;
constexpr const char debugLine[] = …;
constexpr const char debugStr[] = …;
constexpr const char debugStrOffs[] = …;
constexpr const char ehFrame[] = …;
constexpr const char gccExceptTab[] = …;
constexpr const char export_[] = …;
constexpr const char dataInCode[] = …;
constexpr const char functionStarts[] = …;
constexpr const char got[] = …;
constexpr const char header[] = …;
constexpr const char indirectSymbolTable[] = …;
constexpr const char initOffsets[] = …;
constexpr const char const_[] = …;
constexpr const char lazySymbolPtr[] = …;
constexpr const char lazyBinding[] = …;
constexpr const char literals[] = …;
constexpr const char moduleInitFunc[] = …;
constexpr const char moduleTermFunc[] = …;
constexpr const char nonLazySymbolPtr[] = …;
constexpr const char objcCatList[] = …;
constexpr const char objcClassList[] = …;
constexpr const char objcMethList[] = …;
constexpr const char objcClassRefs[] = …;
constexpr const char objcConst[] = …;
constexpr const char objCImageInfo[] = …;
constexpr const char objcStubs[] = …;
constexpr const char objcSelrefs[] = …;
constexpr const char objcMethname[] = …;
constexpr const char objcNonLazyCatList[] = …;
constexpr const char objcNonLazyClassList[] = …;
constexpr const char objcProtoList[] = …;
constexpr const char pageZero[] = …;
constexpr const char pointers[] = …;
constexpr const char rebase[] = …;
constexpr const char staticInit[] = …;
constexpr const char stringTable[] = …;
constexpr const char stubHelper[] = …;
constexpr const char stubs[] = …;
constexpr const char swift[] = …;
constexpr const char symbolTable[] = …;
constexpr const char textCoalNt[] = …;
constexpr const char text[] = …;
constexpr const char threadPtrs[] = …;
constexpr const char threadVars[] = …;
constexpr const char unwindInfo[] = …;
constexpr const char weakBinding[] = …;
constexpr const char zeroFill[] = …;
constexpr const char addrSig[] = …;

} // namespace section_names

void addInputSection(InputSection *inputSection);
} // namespace macho

std::string toString(const macho::InputSection *);

} // namespace lld

#endif
llvm/lld/MachO/InputSection.h
