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1//===- MachOLayoutBuilder.h -------------------------------------*- C++ -*-===//2//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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLVM_LIB_OBJCOPY_MACHO_MACHOLAYOUTBUILDER_H10#define LLVM_LIB_OBJCOPY_MACHO_MACHOLAYOUTBUILDER_H11 12#include "MachOObject.h"13#include "llvm/ObjCopy/MachO/MachOObjcopy.h"14 15namespace llvm {16namespace objcopy {17namespace macho {18 19/// When MachO binaries include a LC_CODE_SIGNATURE load command,20/// the __LINKEDIT data segment will include a section corresponding21/// to the LC_CODE_SIGNATURE load command. This section serves as a signature22/// for the binary. Included in the CodeSignature section is a header followed23/// by a hash of the binary. If present, the CodeSignature section is the24/// last component of the binary.25struct CodeSignatureInfo {26 // NOTE: These values are to be kept in sync with those in27 // LLD's CodeSignatureSection class.28 29 static constexpr uint32_t Align = 16;30 static constexpr uint8_t BlockSizeShift = 12;31 // The binary is read in blocks of the following size.32 static constexpr size_t BlockSize = (1 << BlockSizeShift); // 4 KiB33 // For each block, a SHA256 hash (256 bits, 32 bytes) is written to34 // the CodeSignature section.35 static constexpr size_t HashSize = 256 / 8;36 static constexpr size_t BlobHeadersSize = llvm::alignTo<8>(37 sizeof(llvm::MachO::CS_SuperBlob) + sizeof(llvm::MachO::CS_BlobIndex));38 // The size of the entire header depends upon the filename the binary is being39 // written to, but the rest of the header is fixed in size.40 static constexpr uint32_t FixedHeadersSize =41 BlobHeadersSize + sizeof(llvm::MachO::CS_CodeDirectory);42 43 // The offset relative to the start of the binary where44 // the CodeSignature section should begin.45 uint32_t StartOffset;46 // The size of the entire header, output file name size included.47 uint32_t AllHeadersSize;48 // The number of blocks required to hash the binary.49 uint32_t BlockCount;50 StringRef OutputFileName;51 // The size of the entire CodeSignature section, including both the header and52 // hashes.53 uint32_t Size;54};55 56class MachOLayoutBuilder {57 Object &O;58 bool Is64Bit;59 StringRef OutputFileName;60 uint64_t PageSize;61 CodeSignatureInfo CodeSignature;62 63 // Points to the __LINKEDIT segment if it exists.64 MachO::macho_load_command *LinkEditLoadCommand = nullptr;65 StringTableBuilder StrTableBuilder;66 67 uint32_t computeSizeOfCmds() const;68 void constructStringTable();69 void updateSymbolIndexes();70 void updateDySymTab(MachO::macho_load_command &MLC);71 uint64_t layoutSegments();72 uint64_t layoutRelocations(uint64_t Offset);73 Error layoutTail(uint64_t Offset);74 75 static StringTableBuilder::Kind getStringTableBuilderKind(const Object &O,76 bool Is64Bit);77 78public:79 MachOLayoutBuilder(Object &O, bool Is64Bit, StringRef OutputFileName,80 uint64_t PageSize)81 : O(O), Is64Bit(Is64Bit), OutputFileName(OutputFileName),82 PageSize(PageSize),83 StrTableBuilder(getStringTableBuilderKind(O, Is64Bit)) {}84 85 // Recomputes and updates fields in the given object such as file offsets.86 Error layout();87 88 StringTableBuilder &getStringTableBuilder() { return StrTableBuilder; }89 90 const CodeSignatureInfo &getCodeSignature() const { return CodeSignature; }91};92 93} // end namespace macho94} // end namespace objcopy95} // end namespace llvm96 97#endif // LLVM_LIB_OBJCOPY_MACHO_MACHOLAYOUTBUILDER_H98