llvm-6502/lib/CodeGen/MachOWriter.h
Devang Patel 3e15bf33e0 Use 'static const char' instead of 'static const int'.
Due to darwin gcc bug, one version of darwin linker coalesces
static const int, which defauts PassID based pass identification.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36652 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-02 21:39:20 +00:00

628 lines
26 KiB
C++

//=== MachOWriter.h - Target-independent Mach-O writer support --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Nate Begeman and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the MachOWriter class.
//
//===----------------------------------------------------------------------===//
#ifndef MACHOWRITER_H
#define MACHOWRITER_H
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineRelocation.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetMachOWriterInfo.h"
namespace llvm {
class GlobalVariable;
class Mangler;
class MachineCodeEmitter;
class MachOCodeEmitter;
class OutputBuffer;
/// MachOSym - This struct contains information about each symbol that is
/// added to logical symbol table for the module. This is eventually
/// turned into a real symbol table in the file.
struct MachOSym {
const GlobalValue *GV; // The global value this corresponds to.
std::string GVName; // The mangled name of the global value.
uint32_t n_strx; // index into the string table
uint8_t n_type; // type flag
uint8_t n_sect; // section number or NO_SECT
int16_t n_desc; // see <mach-o/stab.h>
uint64_t n_value; // value for this symbol (or stab offset)
// Constants for the n_sect field
// see <mach-o/nlist.h>
enum { NO_SECT = 0 }; // symbol is not in any section
// Constants for the n_type field
// see <mach-o/nlist.h>
enum { N_UNDF = 0x0, // undefined, n_sect == NO_SECT
N_ABS = 0x2, // absolute, n_sect == NO_SECT
N_SECT = 0xe, // defined in section number n_sect
N_PBUD = 0xc, // prebound undefined (defined in a dylib)
N_INDR = 0xa // indirect
};
// The following bits are OR'd into the types above. For example, a type
// of 0x0f would be an external N_SECT symbol (0x0e | 0x01).
enum { N_EXT = 0x01, // external symbol bit
N_PEXT = 0x10 // private external symbol bit
};
// Constants for the n_desc field
// see <mach-o/loader.h>
enum { REFERENCE_FLAG_UNDEFINED_NON_LAZY = 0,
REFERENCE_FLAG_UNDEFINED_LAZY = 1,
REFERENCE_FLAG_DEFINED = 2,
REFERENCE_FLAG_PRIVATE_DEFINED = 3,
REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY = 4,
REFERENCE_FLAG_PRIVATE_UNDEFINED_LAZY = 5
};
enum { N_NO_DEAD_STRIP = 0x0020, // symbol is not to be dead stripped
N_WEAK_REF = 0x0040, // symbol is weak referenced
N_WEAK_DEF = 0x0080 // coalesced symbol is a weak definition
};
MachOSym(const GlobalValue *gv, std::string name, uint8_t sect,
TargetMachine &TM);
};
/// MachOWriter - This class implements the common target-independent code for
/// writing Mach-O files. Targets should derive a class from this to
/// parameterize the output format.
///
class MachOWriter : public MachineFunctionPass {
friend class MachOCodeEmitter;
public:
static const char ID;
MachineCodeEmitter &getMachineCodeEmitter() const {
return *(MachineCodeEmitter*)MCE;
}
MachOWriter(std::ostream &O, TargetMachine &TM);
virtual ~MachOWriter();
virtual const char *getPassName() const {
return "Mach-O Writer";
}
typedef std::vector<unsigned char> DataBuffer;
protected:
/// Output stream to send the resultant object file to.
///
std::ostream &O;
/// Target machine description.
///
TargetMachine &TM;
/// Mang - The object used to perform name mangling for this module.
///
Mangler *Mang;
/// MCE - The MachineCodeEmitter object that we are exposing to emit machine
/// code for functions to the .o file.
MachOCodeEmitter *MCE;
/// is64Bit/isLittleEndian - This information is inferred from the target
/// machine directly, indicating what header values and flags to set.
bool is64Bit, isLittleEndian;
/// doInitialization - Emit the file header and all of the global variables
/// for the module to the Mach-O file.
bool doInitialization(Module &M);
bool runOnMachineFunction(MachineFunction &MF);
/// doFinalization - Now that the module has been completely processed, emit
/// the Mach-O file to 'O'.
bool doFinalization(Module &M);
/// MachOHeader - This struct contains the header information about a
/// specific architecture type/subtype pair that is emitted to the file.
struct MachOHeader {
uint32_t magic; // mach magic number identifier
uint32_t filetype; // type of file
uint32_t ncmds; // number of load commands
uint32_t sizeofcmds; // the size of all the load commands
uint32_t flags; // flags
uint32_t reserved; // 64-bit only
/// HeaderData - The actual data for the header which we are building
/// up for emission to the file.
DataBuffer HeaderData;
// Constants for the filetype field
// see <mach-o/loader.h> for additional info on the various types
enum { MH_OBJECT = 1, // relocatable object file
MH_EXECUTE = 2, // demand paged executable file
MH_FVMLIB = 3, // fixed VM shared library file
MH_CORE = 4, // core file
MH_PRELOAD = 5, // preloaded executable file
MH_DYLIB = 6, // dynamically bound shared library
MH_DYLINKER = 7, // dynamic link editor
MH_BUNDLE = 8, // dynamically bound bundle file
MH_DYLIB_STUB = 9, // shared library stub for static linking only
MH_DSYM = 10 // companion file wiht only debug sections
};
// Constants for the flags field
enum { MH_NOUNDEFS = 1 << 0,
// the object file has no undefined references
MH_INCRLINK = 1 << 1,
// the object file is the output of an incremental link against
// a base file and cannot be link edited again
MH_DYLDLINK = 1 << 2,
// the object file is input for the dynamic linker and cannot be
// statically link edited again.
MH_BINDATLOAD = 1 << 3,
// the object file's undefined references are bound by the
// dynamic linker when loaded.
MH_PREBOUND = 1 << 4,
// the file has its dynamic undefined references prebound
MH_SPLIT_SEGS = 1 << 5,
// the file has its read-only and read-write segments split
// see <mach/shared_memory_server.h>
MH_LAZY_INIT = 1 << 6,
// the shared library init routine is to be run lazily via
// catching memory faults to its writable segments (obsolete)
MH_TWOLEVEL = 1 << 7,
// the image is using two-level namespace bindings
MH_FORCE_FLAT = 1 << 8,
// the executable is forcing all images to use flat namespace
// bindings.
MH_NOMULTIDEFS = 1 << 8,
// this umbrella guarantees no multiple definitions of symbols
// in its sub-images so the two-level namespace hints can
// always be used.
MH_NOFIXPREBINDING = 1 << 10,
// do not have dyld notify the prebidning agent about this
// executable.
MH_PREBINDABLE = 1 << 11,
// the binary is not prebound but can have its prebinding
// redone. only used when MH_PREBOUND is not set.
MH_ALLMODSBOUND = 1 << 12,
// indicates that this binary binds to all two-level namespace
// modules of its dependent libraries. Only used when
// MH_PREBINDABLE and MH_TWOLEVEL are both set.
MH_SUBSECTIONS_VIA_SYMBOLS = 1 << 13,
// safe to divide up the sections into sub-sections via symbols
// for dead code stripping.
MH_CANONICAL = 1 << 14,
// the binary has been canonicalized via the unprebind operation
MH_WEAK_DEFINES = 1 << 15,
// the final linked image contains external weak symbols
MH_BINDS_TO_WEAK = 1 << 16,
// the final linked image uses weak symbols
MH_ALLOW_STACK_EXECUTION = 1 << 17
// When this bit is set, all stacks in the task will be given
// stack execution privilege. Only used in MH_EXECUTE filetype
};
MachOHeader() : magic(0), filetype(0), ncmds(0), sizeofcmds(0), flags(0),
reserved(0) { }
/// cmdSize - This routine returns the size of the MachOSection as written
/// to disk, depending on whether the destination is a 64 bit Mach-O file.
unsigned cmdSize(bool is64Bit) const {
if (is64Bit)
return 8 * sizeof(uint32_t);
else
return 7 * sizeof(uint32_t);
}
/// setMagic - This routine sets the appropriate value for the 'magic'
/// field based on pointer size and endianness.
void setMagic(bool isLittleEndian, bool is64Bit) {
if (isLittleEndian)
if (is64Bit) magic = 0xcffaedfe;
else magic = 0xcefaedfe;
else
if (is64Bit) magic = 0xfeedfacf;
else magic = 0xfeedface;
}
};
/// Header - An instance of MachOHeader that we will update while we build
/// the file, and then emit during finalization.
MachOHeader Header;
/// MachOSegment - This struct contains the necessary information to
/// emit the load commands for each section in the file.
struct MachOSegment {
uint32_t cmd; // LC_SEGMENT or LC_SEGMENT_64
uint32_t cmdsize; // Total size of this struct and section commands
std::string segname; // segment name
uint64_t vmaddr; // address of this segment
uint64_t vmsize; // size of this segment, may be larger than filesize
uint64_t fileoff; // offset in file
uint64_t filesize; // amount to read from file
uint32_t maxprot; // maximum VM protection
uint32_t initprot; // initial VM protection
uint32_t nsects; // number of sections in this segment
uint32_t flags; // flags
// The following constants are getting pulled in by one of the
// system headers, which creates a neat clash with the enum.
#if !defined(VM_PROT_NONE)
#define VM_PROT_NONE 0x00
#endif
#if !defined(VM_PROT_READ)
#define VM_PROT_READ 0x01
#endif
#if !defined(VM_PROT_WRITE)
#define VM_PROT_WRITE 0x02
#endif
#if !defined(VM_PROT_EXECUTE)
#define VM_PROT_EXECUTE 0x04
#endif
#if !defined(VM_PROT_ALL)
#define VM_PROT_ALL 0x07
#endif
// Constants for the vm protection fields
// see <mach-o/vm_prot.h>
enum { SEG_VM_PROT_NONE = VM_PROT_NONE,
SEG_VM_PROT_READ = VM_PROT_READ, // read permission
SEG_VM_PROT_WRITE = VM_PROT_WRITE, // write permission
SEG_VM_PROT_EXECUTE = VM_PROT_EXECUTE,
SEG_VM_PROT_ALL = VM_PROT_ALL
};
// Constants for the cmd field
// see <mach-o/loader.h>
enum { LC_SEGMENT = 0x01, // segment of this file to be mapped
LC_SEGMENT_64 = 0x19 // 64-bit segment of this file to be mapped
};
/// cmdSize - This routine returns the size of the MachOSection as written
/// to disk, depending on whether the destination is a 64 bit Mach-O file.
unsigned cmdSize(bool is64Bit) const {
if (is64Bit)
return 6 * sizeof(uint32_t) + 4 * sizeof(uint64_t) + 16;
else
return 10 * sizeof(uint32_t) + 16; // addresses only 32 bits
}
MachOSegment(const std::string &seg, bool is64Bit)
: cmd(is64Bit ? LC_SEGMENT_64 : LC_SEGMENT), cmdsize(0), segname(seg),
vmaddr(0), vmsize(0), fileoff(0), filesize(0), maxprot(VM_PROT_ALL),
initprot(VM_PROT_ALL), nsects(0), flags(0) { }
};
/// MachOSection - This struct contains information about each section in a
/// particular segment that is emitted to the file. This is eventually
/// turned into the SectionCommand in the load command for a particlar
/// segment.
struct MachOSection {
std::string sectname; // name of this section,
std::string segname; // segment this section goes in
uint64_t addr; // memory address of this section
uint64_t size; // size in bytes of this section
uint32_t offset; // file offset of this section
uint32_t align; // section alignment (power of 2)
uint32_t reloff; // file offset of relocation entries
uint32_t nreloc; // number of relocation entries
uint32_t flags; // flags (section type and attributes)
uint32_t reserved1; // reserved (for offset or index)
uint32_t reserved2; // reserved (for count or sizeof)
uint32_t reserved3; // reserved (64 bit only)
/// A unique number for this section, which will be used to match symbols
/// to the correct section.
uint32_t Index;
/// SectionData - The actual data for this section which we are building
/// up for emission to the file.
DataBuffer SectionData;
/// RelocBuffer - A buffer to hold the mach-o relocations before we write
/// them out at the appropriate location in the file.
DataBuffer RelocBuffer;
/// Relocations - The relocations that we have encountered so far in this
/// section that we will need to convert to MachORelocation entries when
/// the file is written.
std::vector<MachineRelocation> Relocations;
// Constants for the section types (low 8 bits of flags field)
// see <mach-o/loader.h>
enum { S_REGULAR = 0,
// regular section
S_ZEROFILL = 1,
// zero fill on demand section
S_CSTRING_LITERALS = 2,
// section with only literal C strings
S_4BYTE_LITERALS = 3,
// section with only 4 byte literals
S_8BYTE_LITERALS = 4,
// section with only 8 byte literals
S_LITERAL_POINTERS = 5,
// section with only pointers to literals
S_NON_LAZY_SYMBOL_POINTERS = 6,
// section with only non-lazy symbol pointers
S_LAZY_SYMBOL_POINTERS = 7,
// section with only lazy symbol pointers
S_SYMBOL_STUBS = 8,
// section with only symbol stubs
// byte size of stub in the reserved2 field
S_MOD_INIT_FUNC_POINTERS = 9,
// section with only function pointers for initialization
S_MOD_TERM_FUNC_POINTERS = 10,
// section with only function pointers for termination
S_COALESCED = 11,
// section contains symbols that are coalesced
S_GB_ZEROFILL = 12,
// zero fill on demand section (that can be larger than 4GB)
S_INTERPOSING = 13,
// section with only pairs of function pointers for interposing
S_16BYTE_LITERALS = 14
// section with only 16 byte literals
};
// Constants for the section flags (high 24 bits of flags field)
// see <mach-o/loader.h>
enum { S_ATTR_PURE_INSTRUCTIONS = 1 << 31,
// section contains only true machine instructions
S_ATTR_NO_TOC = 1 << 30,
// section contains coalesced symbols that are not to be in a
// ranlib table of contents
S_ATTR_STRIP_STATIC_SYMS = 1 << 29,
// ok to strip static symbols in this section in files with the
// MY_DYLDLINK flag
S_ATTR_NO_DEAD_STRIP = 1 << 28,
// no dead stripping
S_ATTR_LIVE_SUPPORT = 1 << 27,
// blocks are live if they reference live blocks
S_ATTR_SELF_MODIFYING_CODE = 1 << 26,
// used with i386 code stubs written on by dyld
S_ATTR_DEBUG = 1 << 25,
// a debug section
S_ATTR_SOME_INSTRUCTIONS = 1 << 10,
// section contains some machine instructions
S_ATTR_EXT_RELOC = 1 << 9,
// section has external relocation entries
S_ATTR_LOC_RELOC = 1 << 8
// section has local relocation entries
};
/// cmdSize - This routine returns the size of the MachOSection as written
/// to disk, depending on whether the destination is a 64 bit Mach-O file.
unsigned cmdSize(bool is64Bit) const {
if (is64Bit)
return 7 * sizeof(uint32_t) + 2 * sizeof(uint64_t) + 32;
else
return 9 * sizeof(uint32_t) + 32; // addresses only 32 bits
}
MachOSection(const std::string &seg, const std::string &sect)
: sectname(sect), segname(seg), addr(0), size(0), offset(0), align(2),
reloff(0), nreloc(0), flags(0), reserved1(0), reserved2(0),
reserved3(0) { }
};
private:
/// SectionList - This is the list of sections that we have emitted to the
/// file. Once the file has been completely built, the segment load command
/// SectionCommands are constructed from this info.
std::vector<MachOSection*> SectionList;
/// SectionLookup - This is a mapping from section name to SectionList entry
std::map<std::string, MachOSection*> SectionLookup;
/// GVSection - This is a mapping from a GlobalValue to a MachOSection,
/// to aid in emitting relocations.
std::map<GlobalValue*, MachOSection*> GVSection;
/// GVOffset - This is a mapping from a GlobalValue to an offset from the
/// start of the section in which the GV resides, to aid in emitting
/// relocations.
std::map<GlobalValue*, intptr_t> GVOffset;
/// getSection - Return the section with the specified name, creating a new
/// section if one does not already exist.
MachOSection *getSection(const std::string &seg, const std::string &sect,
unsigned Flags = 0) {
MachOSection *MOS = SectionLookup[seg+sect];
if (MOS) return MOS;
MOS = new MachOSection(seg, sect);
SectionList.push_back(MOS);
MOS->Index = SectionList.size();
MOS->flags = MachOSection::S_REGULAR | Flags;
SectionLookup[seg+sect] = MOS;
return MOS;
}
MachOSection *getTextSection(bool isCode = true) {
if (isCode)
return getSection("__TEXT", "__text",
MachOSection::S_ATTR_PURE_INSTRUCTIONS |
MachOSection::S_ATTR_SOME_INSTRUCTIONS);
else
return getSection("__TEXT", "__text");
}
MachOSection *getBSSSection() {
return getSection("__DATA", "__bss", MachOSection::S_ZEROFILL);
}
MachOSection *getDataSection() {
return getSection("__DATA", "__data");
}
MachOSection *getConstSection(Constant *C) {
const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
if (CVA && CVA->isCString())
return getSection("__TEXT", "__cstring",
MachOSection::S_CSTRING_LITERALS);
const Type *Ty = C->getType();
if (Ty->isPrimitiveType() || Ty->isInteger()) {
unsigned Size = TM.getTargetData()->getTypeSize(Ty);
switch(Size) {
default: break; // Fall through to __TEXT,__const
case 4:
return getSection("__TEXT", "__literal4",
MachOSection::S_4BYTE_LITERALS);
case 8:
return getSection("__TEXT", "__literal8",
MachOSection::S_8BYTE_LITERALS);
case 16:
return getSection("__TEXT", "__literal16",
MachOSection::S_16BYTE_LITERALS);
}
}
return getSection("__TEXT", "__const");
}
MachOSection *getJumpTableSection() {
if (TM.getRelocationModel() == Reloc::PIC_)
return getTextSection(false);
else
return getSection("__TEXT", "__const");
}
/// MachOSymTab - This struct contains information about the offsets and
/// size of symbol table information.
/// segment.
struct MachOSymTab {
uint32_t cmd; // LC_SYMTAB
uint32_t cmdsize; // sizeof( MachOSymTab )
uint32_t symoff; // symbol table offset
uint32_t nsyms; // number of symbol table entries
uint32_t stroff; // string table offset
uint32_t strsize; // string table size in bytes
// Constants for the cmd field
// see <mach-o/loader.h>
enum { LC_SYMTAB = 0x02 // link-edit stab symbol table info
};
MachOSymTab() : cmd(LC_SYMTAB), cmdsize(6 * sizeof(uint32_t)), symoff(0),
nsyms(0), stroff(0), strsize(0) { }
};
/// MachOSymTab - This struct contains information about the offsets and
/// size of symbol table information.
/// segment.
struct MachODySymTab {
uint32_t cmd; // LC_DYSYMTAB
uint32_t cmdsize; // sizeof( MachODySymTab )
uint32_t ilocalsym; // index to local symbols
uint32_t nlocalsym; // number of local symbols
uint32_t iextdefsym; // index to externally defined symbols
uint32_t nextdefsym; // number of externally defined symbols
uint32_t iundefsym; // index to undefined symbols
uint32_t nundefsym; // number of undefined symbols
uint32_t tocoff; // file offset to table of contents
uint32_t ntoc; // number of entries in table of contents
uint32_t modtaboff; // file offset to module table
uint32_t nmodtab; // number of module table entries
uint32_t extrefsymoff; // offset to referenced symbol table
uint32_t nextrefsyms; // number of referenced symbol table entries
uint32_t indirectsymoff; // file offset to the indirect symbol table
uint32_t nindirectsyms; // number of indirect symbol table entries
uint32_t extreloff; // offset to external relocation entries
uint32_t nextrel; // number of external relocation entries
uint32_t locreloff; // offset to local relocation entries
uint32_t nlocrel; // number of local relocation entries
// Constants for the cmd field
// see <mach-o/loader.h>
enum { LC_DYSYMTAB = 0x0B // dynamic link-edit symbol table info
};
MachODySymTab() : cmd(LC_DYSYMTAB), cmdsize(20 * sizeof(uint32_t)),
ilocalsym(0), nlocalsym(0), iextdefsym(0), nextdefsym(0),
iundefsym(0), nundefsym(0), tocoff(0), ntoc(0), modtaboff(0),
nmodtab(0), extrefsymoff(0), nextrefsyms(0), indirectsymoff(0),
nindirectsyms(0), extreloff(0), nextrel(0), locreloff(0), nlocrel(0) { }
};
/// SymTab - The "stab" style symbol table information
MachOSymTab SymTab;
/// DySymTab - symbol table info for the dynamic link editor
MachODySymTab DySymTab;
struct MachOSymCmp {
// FIXME: this does not appear to be sorting 'f' after 'F'
bool operator()(const MachOSym &LHS, const MachOSym &RHS) {
return LHS.GVName < RHS.GVName;
}
};
/// PartitionByLocal - Simple boolean predicate that returns true if Sym is
/// a local symbol rather than an external symbol.
static bool PartitionByLocal(const MachOSym &Sym);
/// PartitionByDefined - Simple boolean predicate that returns true if Sym
/// is defined in this module.
static bool PartitionByDefined(const MachOSym &Sym);
protected:
/// SymbolTable - This is the list of symbols we have emitted to the file.
/// This actually gets rearranged before emission to the file (to put the
/// local symbols first in the list).
std::vector<MachOSym> SymbolTable;
/// SymT - A buffer to hold the symbol table before we write it out at the
/// appropriate location in the file.
DataBuffer SymT;
/// StrT - A buffer to hold the string table before we write it out at the
/// appropriate location in the file.
DataBuffer StrT;
/// PendingSyms - This is a list of externally defined symbols that we have
/// been asked to emit, but have not seen a reference to. When a reference
/// is seen, the symbol will move from this list to the SymbolTable.
std::vector<GlobalValue*> PendingGlobals;
/// DynamicSymbolTable - This is just a vector of indices into
/// SymbolTable to aid in emitting the DYSYMTAB load command.
std::vector<unsigned> DynamicSymbolTable;
static void InitMem(const Constant *C, void *Addr, intptr_t Offset,
const TargetData *TD,
std::vector<MachineRelocation> &MRs);
private:
void AddSymbolToSection(MachOSection *MOS, GlobalVariable *GV);
void EmitGlobal(GlobalVariable *GV);
void EmitHeaderAndLoadCommands();
void EmitSections();
void BufferSymbolAndStringTable();
void CalculateRelocations(MachOSection &MOS);
MachineRelocation GetJTRelocation(unsigned Offset,
MachineBasicBlock *MBB) const {
return TM.getMachOWriterInfo()->GetJTRelocation(Offset, MBB);
}
/// GetTargetRelocation - Returns the number of relocations.
unsigned GetTargetRelocation(MachineRelocation &MR,
unsigned FromIdx,
unsigned ToAddr,
unsigned ToIndex,
OutputBuffer &RelocOut,
OutputBuffer &SecOut,
bool Scattered,
bool Extern) {
return TM.getMachOWriterInfo()->GetTargetRelocation(MR, FromIdx, ToAddr,
ToIndex, RelocOut,
SecOut, Scattered,
Extern);
}
};
}
#endif