llvm/lld/COFF/DLL.cpp

//===- DLL.cpp ------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines various types of chunks for the DLL import or export
// descriptor tables. They are inherently Windows-specific.
// You need to read Microsoft PE/COFF spec to understand details
// about the data structures.
//
// If you are not particularly interested in linking against Windows
// DLL, you can skip this file, and you should still be able to
// understand the rest of the linker.
//
//===----------------------------------------------------------------------===//

#include "DLL.h"
#include "COFFLinkerContext.h"
#include "Chunks.h"
#include "SymbolTable.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Object/COFF.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Path.h"

usingnamespacellvm;
usingnamespacellvm::object;
usingnamespacellvm::support::endian;
usingnamespacellvm::COFF;

namespace lld::coff {
namespace {

// Import table

// A chunk for the import descriptor table.
class HintNameChunk : public NonSectionChunk { … };

// A chunk for the import descriptor table.
class LookupChunk : public NonSectionChunk { … };

// A chunk for the import descriptor table.
// This chunk represent import-by-ordinal symbols.
// See Microsoft PE/COFF spec 7.1. Import Header for details.
class OrdinalOnlyChunk : public NonSectionChunk { … };

// A chunk for the import descriptor table.
class ImportDirectoryChunk : public NonSectionChunk { … };

// A chunk representing null terminator in the import table.
// Contents of this chunk is always null bytes.
class NullChunk : public NonSectionChunk { … };

static std::vector<std::vector<DefinedImportData *>>
binImports(COFFLinkerContext &ctx,
           const std::vector<DefinedImportData *> &imports) { … }

// See Microsoft PE/COFF spec 4.3 for details.

// A chunk for the delay import descriptor table etnry.
class DelayDirectoryChunk : public NonSectionChunk { … };

// Initial contents for delay-loaded functions.
// This code calls __delayLoadHelper2 function to resolve a symbol
// which then overwrites its jump table slot with the result
// for subsequent function calls.
static const uint8_t thunkX64[] = …;

static const uint8_t tailMergeX64[] = …;

static const uint8_t tailMergeUnwindInfoX64[] = …;

static const uint8_t thunkX86[] = …;

static const uint8_t tailMergeX86[] = …;

static const uint8_t thunkARM[] = …;

static const uint8_t tailMergeARM[] = …;

static const uint8_t thunkARM64[] = …;

static const uint8_t tailMergeARM64[] = …;

// A chunk for the delay import thunk.
class ThunkChunkX64 : public NonSectionCodeChunk { … };

class TailMergeChunkX64 : public NonSectionCodeChunk { … };

class TailMergePDataChunkX64 : public NonSectionChunk { … };

class TailMergeUnwindInfoX64 : public NonSectionChunk { … };

class ThunkChunkX86 : public NonSectionCodeChunk { … };

class TailMergeChunkX86 : public NonSectionCodeChunk { … };

class ThunkChunkARM : public NonSectionCodeChunk { … };

class TailMergeChunkARM : public NonSectionCodeChunk { … };

class ThunkChunkARM64 : public NonSectionCodeChunk { … };

class TailMergeChunkARM64 : public NonSectionCodeChunk { … };

// A chunk for the import descriptor table.
class DelayAddressChunk : public NonSectionChunk { … };

// Export table
// Read Microsoft PE/COFF spec 5.3 for details.

// A chunk for the export descriptor table.
class ExportDirectoryChunk : public NonSectionChunk { … };

class AddressTableChunk : public NonSectionChunk { … };

class NamePointersChunk : public NonSectionChunk { … };

class ExportOrdinalChunk : public NonSectionChunk { … };

} // anonymous namespace

void IdataContents::create(COFFLinkerContext &ctx) { … }

std::vector<Chunk *> DelayLoadContents::getChunks() { … }

std::vector<Chunk *> DelayLoadContents::getDataChunks() { … }

uint64_t DelayLoadContents::getDirSize() { … }

void DelayLoadContents::create(Defined *h) { … }

Chunk *DelayLoadContents::newTailMergeChunk(Chunk *dir) { … }

Chunk *DelayLoadContents::newTailMergeUnwindInfoChunk() { … }
Chunk *DelayLoadContents::newTailMergePDataChunk(Chunk *tm, Chunk *unwind) { … }

Chunk *DelayLoadContents::newThunkChunk(DefinedImportData *s,
                                        Chunk *tailMerge) { … }

EdataContents::EdataContents(COFFLinkerContext &ctx) : … { … }

} // namespace lld::coff