413 lines
17 KiB
C++
413 lines
17 KiB
C++
//=== MachO.h - Mach-O structures and constants -----------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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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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//
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// This file defines MachO .
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//
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//===----------------------------------------------------------------------===//
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#ifndef MACHO_H
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#define MACHO_H
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#include "llvm/CodeGen/BinaryObject.h"
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#include <string>
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#include <vector>
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namespace llvm {
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class GlobalValue;
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class MCAsmInfo;
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/// MachOSym - This struct contains information about each symbol that is
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/// added to logical symbol table for the module. This is eventually
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/// turned into a real symbol table in the file.
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struct MachOSym {
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const GlobalValue *GV; // The global value this corresponds to.
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std::string GVName; // The mangled name of the global value.
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uint32_t n_strx; // index into the string table
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uint8_t n_type; // type flag
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uint8_t n_sect; // section number or NO_SECT
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int16_t n_desc; // see <mach-o/stab.h>
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uint64_t n_value; // value for this symbol (or stab offset)
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// Constants for the n_sect field
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// see <mach-o/nlist.h>
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enum { NO_SECT = 0 }; // symbol is not in any section
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// Constants for the n_type field
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// see <mach-o/nlist.h>
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enum { N_UNDF = 0x0, // undefined, n_sect == NO_SECT
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N_ABS = 0x2, // absolute, n_sect == NO_SECT
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N_SECT = 0xe, // defined in section number n_sect
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N_PBUD = 0xc, // prebound undefined (defined in a dylib)
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N_INDR = 0xa // indirect
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};
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// The following bits are OR'd into the types above. For example, a type
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// of 0x0f would be an external N_SECT symbol (0x0e | 0x01).
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enum { N_EXT = 0x01, // external symbol bit
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N_PEXT = 0x10 // private external symbol bit
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};
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// Constants for the n_desc field
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// see <mach-o/loader.h>
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enum { REFERENCE_FLAG_UNDEFINED_NON_LAZY = 0,
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REFERENCE_FLAG_UNDEFINED_LAZY = 1,
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REFERENCE_FLAG_DEFINED = 2,
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REFERENCE_FLAG_PRIVATE_DEFINED = 3,
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REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY = 4,
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REFERENCE_FLAG_PRIVATE_UNDEFINED_LAZY = 5
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};
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enum { N_NO_DEAD_STRIP = 0x0020, // symbol is not to be dead stripped
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N_WEAK_REF = 0x0040, // symbol is weak referenced
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N_WEAK_DEF = 0x0080 // coalesced symbol is a weak definition
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};
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MachOSym(const GlobalValue *gv, std::string name, uint8_t sect,
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const MCAsmInfo *MAI);
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struct SymCmp {
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// FIXME: this does not appear to be sorting 'f' after 'F'
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bool operator()(const MachOSym &LHS, const MachOSym &RHS) {
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return LHS.GVName < RHS.GVName;
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}
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};
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/// PartitionByLocal - Simple boolean predicate that returns true if Sym is
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/// a local symbol rather than an external symbol.
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static inline bool PartitionByLocal(const MachOSym &Sym) {
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return (Sym.n_type & (MachOSym::N_EXT | MachOSym::N_PEXT)) == 0;
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}
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/// PartitionByDefined - Simple boolean predicate that returns true if Sym is
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/// defined in this module.
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static inline bool PartitionByDefined(const MachOSym &Sym) {
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// FIXME: Do N_ABS or N_INDR count as defined?
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return (Sym.n_type & MachOSym::N_SECT) == MachOSym::N_SECT;
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}
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}; // end struct MachOSym
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/// MachOHeader - This struct contains the header information about a
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/// specific architecture type/subtype pair that is emitted to the file.
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struct MachOHeader {
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uint32_t magic; // mach magic number identifier
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uint32_t filetype; // type of file
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uint32_t ncmds; // number of load commands
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uint32_t sizeofcmds; // the size of all the load commands
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uint32_t flags; // flags
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uint32_t reserved; // 64-bit only
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/// HeaderData - The actual data for the header which we are building
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/// up for emission to the file.
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std::vector<unsigned char> HeaderData;
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// Constants for the filetype field
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// see <mach-o/loader.h> for additional info on the various types
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enum { MH_OBJECT = 1, // relocatable object file
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MH_EXECUTE = 2, // demand paged executable file
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MH_FVMLIB = 3, // fixed VM shared library file
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MH_CORE = 4, // core file
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MH_PRELOAD = 5, // preloaded executable file
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MH_DYLIB = 6, // dynamically bound shared library
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MH_DYLINKER = 7, // dynamic link editor
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MH_BUNDLE = 8, // dynamically bound bundle file
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MH_DYLIB_STUB = 9, // shared library stub for static linking only
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MH_DSYM = 10 // companion file wiht only debug sections
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};
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// Constants for the flags field
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enum { MH_NOUNDEFS = 1 << 0,
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// the object file has no undefined references
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MH_INCRLINK = 1 << 1,
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// the object file is the output of an incremental link against
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// a base file and cannot be link edited again
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MH_DYLDLINK = 1 << 2,
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// the object file is input for the dynamic linker and cannot be
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// statically link edited again.
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MH_BINDATLOAD = 1 << 3,
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// the object file's undefined references are bound by the
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// dynamic linker when loaded.
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MH_PREBOUND = 1 << 4,
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// the file has its dynamic undefined references prebound
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MH_SPLIT_SEGS = 1 << 5,
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// the file has its read-only and read-write segments split
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// see <mach/shared_memory_server.h>
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MH_LAZY_INIT = 1 << 6,
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// the shared library init routine is to be run lazily via
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// catching memory faults to its writable segments (obsolete)
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MH_TWOLEVEL = 1 << 7,
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// the image is using two-level namespace bindings
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MH_FORCE_FLAT = 1 << 8,
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// the executable is forcing all images to use flat namespace
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// bindings.
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MH_NOMULTIDEFS = 1 << 8,
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// this umbrella guarantees no multiple definitions of symbols
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// in its sub-images so the two-level namespace hints can
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// always be used.
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MH_NOFIXPREBINDING = 1 << 10,
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// do not have dyld notify the prebidning agent about this
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// executable.
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MH_PREBINDABLE = 1 << 11,
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// the binary is not prebound but can have its prebinding
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// redone. only used when MH_PREBOUND is not set.
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MH_ALLMODSBOUND = 1 << 12,
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// indicates that this binary binds to all two-level namespace
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// modules of its dependent libraries. Only used when
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// MH_PREBINDABLE and MH_TWOLEVEL are both set.
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MH_SUBSECTIONS_VIA_SYMBOLS = 1 << 13,
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// safe to divide up the sections into sub-sections via symbols
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// for dead code stripping.
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MH_CANONICAL = 1 << 14,
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// the binary has been canonicalized via the unprebind operation
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MH_WEAK_DEFINES = 1 << 15,
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// the final linked image contains external weak symbols
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MH_BINDS_TO_WEAK = 1 << 16,
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// the final linked image uses weak symbols
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MH_ALLOW_STACK_EXECUTION = 1 << 17
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// When this bit is set, all stacks in the task will be given
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// stack execution privilege. Only used in MH_EXECUTE filetype
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};
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MachOHeader() : magic(0), filetype(0), ncmds(0), sizeofcmds(0), flags(0),
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reserved(0) {}
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/// cmdSize - This routine returns the size of the MachOSection as written
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/// to disk, depending on whether the destination is a 64 bit Mach-O file.
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unsigned cmdSize(bool is64Bit) const {
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if (is64Bit)
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return 8 * sizeof(uint32_t);
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else
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return 7 * sizeof(uint32_t);
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}
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/// setMagic - This routine sets the appropriate value for the 'magic'
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/// field based on pointer size and endianness.
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void setMagic(bool isLittleEndian, bool is64Bit) {
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if (isLittleEndian)
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if (is64Bit) magic = 0xcffaedfe;
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else magic = 0xcefaedfe;
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else
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if (is64Bit) magic = 0xfeedfacf;
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else magic = 0xfeedface;
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}
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}; // end struct MachOHeader
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/// MachOSegment - This struct contains the necessary information to
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/// emit the load commands for each section in the file.
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struct MachOSegment {
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uint32_t cmd; // LC_SEGMENT or LC_SEGMENT_64
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uint32_t cmdsize; // Total size of this struct and section commands
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std::string segname; // segment name
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uint64_t vmaddr; // address of this segment
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uint64_t vmsize; // size of this segment, may be larger than filesize
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uint64_t fileoff; // offset in file
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uint64_t filesize; // amount to read from file
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uint32_t maxprot; // maximum VM protection
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uint32_t initprot; // initial VM protection
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uint32_t nsects; // number of sections in this segment
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uint32_t flags; // flags
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// The following constants are getting pulled in by one of the
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// system headers, which creates a neat clash with the enum.
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#if !defined(VM_PROT_NONE)
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#define VM_PROT_NONE 0x00
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#endif
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#if !defined(VM_PROT_READ)
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#define VM_PROT_READ 0x01
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#endif
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#if !defined(VM_PROT_WRITE)
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#define VM_PROT_WRITE 0x02
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#endif
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#if !defined(VM_PROT_EXECUTE)
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#define VM_PROT_EXECUTE 0x04
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#endif
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#if !defined(VM_PROT_ALL)
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#define VM_PROT_ALL 0x07
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#endif
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// Constants for the vm protection fields
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// see <mach-o/vm_prot.h>
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enum { SEG_VM_PROT_NONE = VM_PROT_NONE,
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SEG_VM_PROT_READ = VM_PROT_READ, // read permission
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SEG_VM_PROT_WRITE = VM_PROT_WRITE, // write permission
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SEG_VM_PROT_EXECUTE = VM_PROT_EXECUTE,
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SEG_VM_PROT_ALL = VM_PROT_ALL
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};
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// Constants for the cmd field
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// see <mach-o/loader.h>
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enum { LC_SEGMENT = 0x01, // segment of this file to be mapped
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LC_SEGMENT_64 = 0x19 // 64-bit segment of this file to be mapped
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};
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/// cmdSize - This routine returns the size of the MachOSection as written
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/// to disk, depending on whether the destination is a 64 bit Mach-O file.
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unsigned cmdSize(bool is64Bit) const {
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if (is64Bit)
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return 6 * sizeof(uint32_t) + 4 * sizeof(uint64_t) + 16;
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else
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return 10 * sizeof(uint32_t) + 16; // addresses only 32 bits
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}
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MachOSegment(const std::string &seg, bool is64Bit)
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: cmd(is64Bit ? LC_SEGMENT_64 : LC_SEGMENT), cmdsize(0), segname(seg),
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vmaddr(0), vmsize(0), fileoff(0), filesize(0), maxprot(VM_PROT_ALL),
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initprot(VM_PROT_ALL), nsects(0), flags(0) { }
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};
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/// MachOSection - This struct contains information about each section in a
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/// particular segment that is emitted to the file. This is eventually
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/// turned into the SectionCommand in the load command for a particlar
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/// segment.
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struct MachOSection : public BinaryObject {
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std::string sectname; // name of this section,
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std::string segname; // segment this section goes in
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uint64_t addr; // memory address of this section
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uint32_t offset; // file offset of this section
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uint32_t align; // section alignment (power of 2)
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uint32_t reloff; // file offset of relocation entries
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uint32_t nreloc; // number of relocation entries
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uint32_t flags; // flags (section type and attributes)
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uint32_t reserved1; // reserved (for offset or index)
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uint32_t reserved2; // reserved (for count or sizeof)
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uint32_t reserved3; // reserved (64 bit only)
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/// A unique number for this section, which will be used to match symbols
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/// to the correct section.
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uint32_t Index;
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/// RelocBuffer - A buffer to hold the mach-o relocations before we write
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/// them out at the appropriate location in the file.
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std::vector<unsigned char> RelocBuffer;
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// Constants for the section types (low 8 bits of flags field)
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// see <mach-o/loader.h>
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enum { S_REGULAR = 0,
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// regular section
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S_ZEROFILL = 1,
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// zero fill on demand section
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S_CSTRING_LITERALS = 2,
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// section with only literal C strings
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S_4BYTE_LITERALS = 3,
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// section with only 4 byte literals
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S_8BYTE_LITERALS = 4,
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// section with only 8 byte literals
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S_LITERAL_POINTERS = 5,
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// section with only pointers to literals
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S_NON_LAZY_SYMBOL_POINTERS = 6,
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// section with only non-lazy symbol pointers
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S_LAZY_SYMBOL_POINTERS = 7,
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// section with only lazy symbol pointers
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S_SYMBOL_STUBS = 8,
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// section with only symbol stubs
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// byte size of stub in the reserved2 field
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S_MOD_INIT_FUNC_POINTERS = 9,
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// section with only function pointers for initialization
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S_MOD_TERM_FUNC_POINTERS = 10,
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// section with only function pointers for termination
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S_COALESCED = 11,
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// section contains symbols that are coalesced
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S_GB_ZEROFILL = 12,
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// zero fill on demand section (that can be larger than 4GB)
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S_INTERPOSING = 13,
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// section with only pairs of function pointers for interposing
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S_16BYTE_LITERALS = 14
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// section with only 16 byte literals
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};
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// Constants for the section flags (high 24 bits of flags field)
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// see <mach-o/loader.h>
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enum { S_ATTR_PURE_INSTRUCTIONS = 1 << 31,
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// section contains only true machine instructions
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S_ATTR_NO_TOC = 1 << 30,
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// section contains coalesced symbols that are not to be in a
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// ranlib table of contents
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S_ATTR_STRIP_STATIC_SYMS = 1 << 29,
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// ok to strip static symbols in this section in files with the
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// MY_DYLDLINK flag
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S_ATTR_NO_DEAD_STRIP = 1 << 28,
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// no dead stripping
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S_ATTR_LIVE_SUPPORT = 1 << 27,
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// blocks are live if they reference live blocks
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S_ATTR_SELF_MODIFYING_CODE = 1 << 26,
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// used with i386 code stubs written on by dyld
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S_ATTR_DEBUG = 1 << 25,
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// a debug section
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S_ATTR_SOME_INSTRUCTIONS = 1 << 10,
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// section contains some machine instructions
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S_ATTR_EXT_RELOC = 1 << 9,
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// section has external relocation entries
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S_ATTR_LOC_RELOC = 1 << 8
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// section has local relocation entries
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};
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/// cmdSize - This routine returns the size of the MachOSection as written
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/// to disk, depending on whether the destination is a 64 bit Mach-O file.
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unsigned cmdSize(bool is64Bit) const {
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if (is64Bit)
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return 7 * sizeof(uint32_t) + 2 * sizeof(uint64_t) + 32;
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else
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return 9 * sizeof(uint32_t) + 32; // addresses only 32 bits
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}
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MachOSection(const std::string &seg, const std::string §)
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: BinaryObject(), sectname(sect), segname(seg), addr(0), offset(0),
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align(2), reloff(0), nreloc(0), flags(0), reserved1(0), reserved2(0),
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reserved3(0) { }
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}; // end struct MachOSection
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/// MachOSymTab - This struct contains information about the offsets and
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/// size of symbol table information.
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/// segment.
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struct MachODySymTab {
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uint32_t cmd; // LC_DYSYMTAB
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uint32_t cmdsize; // sizeof(MachODySymTab)
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uint32_t ilocalsym; // index to local symbols
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uint32_t nlocalsym; // number of local symbols
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uint32_t iextdefsym; // index to externally defined symbols
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uint32_t nextdefsym; // number of externally defined symbols
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uint32_t iundefsym; // index to undefined symbols
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uint32_t nundefsym; // number of undefined symbols
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uint32_t tocoff; // file offset to table of contents
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uint32_t ntoc; // number of entries in table of contents
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uint32_t modtaboff; // file offset to module table
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uint32_t nmodtab; // number of module table entries
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uint32_t extrefsymoff; // offset to referenced symbol table
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uint32_t nextrefsyms; // number of referenced symbol table entries
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uint32_t indirectsymoff; // file offset to the indirect symbol table
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uint32_t nindirectsyms; // number of indirect symbol table entries
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uint32_t extreloff; // offset to external relocation entries
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uint32_t nextrel; // number of external relocation entries
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uint32_t locreloff; // offset to local relocation entries
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uint32_t nlocrel; // number of local relocation entries
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// Constants for the cmd field
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// see <mach-o/loader.h>
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enum { LC_DYSYMTAB = 0x0B // dynamic link-edit symbol table info
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};
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MachODySymTab() : cmd(LC_DYSYMTAB), cmdsize(20 * sizeof(uint32_t)),
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ilocalsym(0), nlocalsym(0), iextdefsym(0), nextdefsym(0),
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iundefsym(0), nundefsym(0), tocoff(0), ntoc(0), modtaboff(0),
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nmodtab(0), extrefsymoff(0), nextrefsyms(0), indirectsymoff(0),
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nindirectsyms(0), extreloff(0), nextrel(0), locreloff(0), nlocrel(0) {}
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}; // end struct MachODySymTab
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} // end namespace llvm
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#endif
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