| //===- lib/MC/MCAssembler.cpp - Assembler Backend Implementation ----------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/MC/MCAssembler.h" |
| |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/MC/MCSectionMachO.h" |
| #include "llvm/Support/DataTypes.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetMachOWriterInfo.h" |
| |
| using namespace llvm; |
| |
| namespace { |
| |
| class MachObjectWriter { |
| // See <mach-o/loader.h>. |
| enum { |
| Header_Magic32 = 0xFEEDFACE, |
| Header_Magic64 = 0xFEEDFACF |
| }; |
| |
| static const unsigned Header32Size = 28; |
| static const unsigned Header64Size = 32; |
| static const unsigned SegmentLoadCommand32Size = 56; |
| static const unsigned Section32Size = 68; |
| |
| enum HeaderFileType { |
| HFT_Object = 0x1 |
| }; |
| |
| enum LoadCommandType { |
| LCT_Segment = 0x1 |
| }; |
| |
| raw_ostream &OS; |
| bool IsLSB; |
| |
| public: |
| MachObjectWriter(raw_ostream &_OS, bool _IsLSB = true) |
| : OS(_OS), IsLSB(_IsLSB) { |
| } |
| |
| /// @name Helper Methods |
| /// @{ |
| |
| void Write8(uint8_t Value) { |
| OS << char(Value); |
| } |
| |
| void Write16(uint16_t Value) { |
| if (IsLSB) { |
| Write8(uint8_t(Value >> 0)); |
| Write8(uint8_t(Value >> 8)); |
| } else { |
| Write8(uint8_t(Value >> 8)); |
| Write8(uint8_t(Value >> 0)); |
| } |
| } |
| |
| void Write32(uint32_t Value) { |
| if (IsLSB) { |
| Write16(uint16_t(Value >> 0)); |
| Write16(uint16_t(Value >> 16)); |
| } else { |
| Write16(uint16_t(Value >> 16)); |
| Write16(uint16_t(Value >> 0)); |
| } |
| } |
| |
| void Write64(uint64_t Value) { |
| if (IsLSB) { |
| Write32(uint32_t(Value >> 0)); |
| Write32(uint32_t(Value >> 32)); |
| } else { |
| Write32(uint32_t(Value >> 32)); |
| Write32(uint32_t(Value >> 0)); |
| } |
| } |
| |
| void WriteZeros(unsigned N) { |
| const char Zeros[16] = { 0 }; |
| |
| for (unsigned i = 0, e = N / 16; i != e; ++i) |
| OS << StringRef(Zeros, 16); |
| |
| OS << StringRef(Zeros, N % 16); |
| } |
| |
| void WriteString(const StringRef &Str, unsigned ZeroFillSize = 0) { |
| OS << Str; |
| if (ZeroFillSize) |
| WriteZeros(ZeroFillSize - Str.size()); |
| } |
| |
| /// @} |
| |
| static unsigned getPrologSize32(unsigned NumSections) { |
| return Header32Size + SegmentLoadCommand32Size + |
| NumSections * Section32Size; |
| } |
| |
| void WriteHeader32(unsigned NumSections) { |
| // struct mach_header (28 bytes) |
| |
| uint64_t Start = OS.tell(); |
| (void) Start; |
| |
| Write32(Header_Magic32); |
| |
| // FIXME: Support cputype. |
| Write32(TargetMachOWriterInfo::HDR_CPU_TYPE_I386); |
| |
| // FIXME: Support cpusubtype. |
| Write32(TargetMachOWriterInfo::HDR_CPU_SUBTYPE_I386_ALL); |
| |
| Write32(HFT_Object); |
| |
| // Object files have a single load command, the segment. |
| Write32(1); |
| Write32(SegmentLoadCommand32Size + NumSections * Section32Size); |
| Write32(0); // Flags |
| |
| assert(OS.tell() - Start == Header32Size); |
| } |
| |
| void WriteLoadCommandHeader(uint32_t Cmd, uint32_t CmdSize) { |
| assert((CmdSize & 0x3) == 0 && "Invalid size!"); |
| |
| Write32(Cmd); |
| Write32(CmdSize); |
| } |
| |
| /// WriteSegmentLoadCommand32 - Write a 32-bit segment load command. |
| /// |
| /// \arg NumSections - The number of sections in this segment. |
| /// \arg SectionDataSize - The total size of the sections. |
| void WriteSegmentLoadCommand32(unsigned NumSections, |
| uint64_t SectionDataSize) { |
| // struct segment_command (56 bytes) |
| |
| uint64_t Start = OS.tell(); |
| (void) Start; |
| |
| Write32(LCT_Segment); |
| Write32(SegmentLoadCommand32Size + NumSections * Section32Size); |
| |
| WriteString("", 16); |
| Write32(0); // vmaddr |
| Write32(SectionDataSize); // vmsize |
| Write32(Header32Size + SegmentLoadCommand32Size + |
| NumSections * Section32Size); // file offset |
| Write32(SectionDataSize); // file size |
| Write32(0x7); // maxprot |
| Write32(0x7); // initprot |
| Write32(NumSections); |
| Write32(0); // flags |
| |
| assert(OS.tell() - Start == SegmentLoadCommand32Size); |
| } |
| |
| void WriteSection32(const MCSectionData &SD) { |
| // struct section (68 bytes) |
| |
| uint64_t Start = OS.tell(); |
| (void) Start; |
| |
| // FIXME: cast<> support! |
| const MCSectionMachO &Section = |
| static_cast<const MCSectionMachO&>(SD.getSection()); |
| WriteString(Section.getSectionName(), 16); |
| WriteString(Section.getSegmentName(), 16); |
| Write32(0); // address |
| Write32(SD.getFileSize()); // size |
| Write32(SD.getFileOffset()); |
| |
| assert(isPowerOf2_32(SD.getAlignment()) && "Invalid alignment!"); |
| Write32(Log2_32(SD.getAlignment())); |
| Write32(0); // file offset of relocation entries |
| Write32(0); // number of relocation entrions |
| Write32(Section.getTypeAndAttributes()); |
| Write32(0); // reserved1 |
| Write32(Section.getStubSize()); // reserved2 |
| |
| assert(OS.tell() - Start == Section32Size); |
| } |
| }; |
| |
| } |
| |
| /* *** */ |
| |
| MCFragment::MCFragment() : Kind(FragmentType(~0)) { |
| } |
| |
| MCFragment::MCFragment(FragmentType _Kind, MCSectionData *SD) |
| : Kind(_Kind), |
| FileOffset(~UINT64_C(0)), |
| FileSize(~UINT64_C(0)) |
| { |
| if (SD) |
| SD->getFragmentList().push_back(this); |
| } |
| |
| MCFragment::~MCFragment() { |
| } |
| |
| /* *** */ |
| |
| MCSectionData::MCSectionData() : Section(*(MCSection*)0) {} |
| |
| MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A) |
| : Section(_Section), |
| Alignment(1), |
| FileOffset(~UINT64_C(0)), |
| FileSize(~UINT64_C(0)) |
| { |
| if (A) |
| A->getSectionList().push_back(this); |
| } |
| |
| /* *** */ |
| |
| MCAssembler::MCAssembler(raw_ostream &_OS) : OS(_OS) {} |
| |
| MCAssembler::~MCAssembler() { |
| } |
| |
| void MCAssembler::LayoutSection(MCSectionData &SD) { |
| uint64_t FileOffset = SD.getFileOffset(); |
| uint64_t SectionOffset = 0; |
| |
| for (MCSectionData::iterator it = SD.begin(), ie = SD.end(); it != ie; ++it) { |
| MCFragment &F = *it; |
| |
| F.setFileOffset(FileOffset); |
| |
| // Evaluate fragment size. |
| switch (F.getKind()) { |
| case MCFragment::FT_Align: { |
| MCAlignFragment &AF = cast<MCAlignFragment>(F); |
| |
| uint64_t AlignedOffset = |
| RoundUpToAlignment(SectionOffset, AF.getAlignment()); |
| uint64_t PaddingBytes = AlignedOffset - SectionOffset; |
| |
| if (PaddingBytes > AF.getMaxBytesToEmit()) |
| AF.setFileSize(0); |
| else |
| AF.setFileSize(PaddingBytes); |
| break; |
| } |
| |
| case MCFragment::FT_Data: |
| case MCFragment::FT_Fill: |
| F.setFileSize(F.getMaxFileSize()); |
| break; |
| |
| case MCFragment::FT_Org: { |
| MCOrgFragment &OF = cast<MCOrgFragment>(F); |
| |
| if (!OF.getOffset().isAbsolute()) |
| llvm_unreachable("FIXME: Not yet implemented!"); |
| uint64_t OrgOffset = OF.getOffset().getConstant(); |
| |
| // FIXME: We need a way to communicate this error. |
| if (OrgOffset < SectionOffset) |
| llvm_report_error("invalid .org offset '" + Twine(OrgOffset) + |
| "' (section offset '" + Twine(SectionOffset) + "'"); |
| |
| F.setFileSize(OrgOffset - SectionOffset); |
| break; |
| } |
| } |
| |
| FileOffset += F.getFileSize(); |
| SectionOffset += F.getFileSize(); |
| } |
| |
| // FIXME: Pad section? |
| SD.setFileSize(FileOffset - SD.getFileOffset()); |
| } |
| |
| /// WriteFileData - Write the \arg F data to the output file. |
| static void WriteFileData(raw_ostream &OS, const MCFragment &F, |
| MachObjectWriter &MOW) { |
| uint64_t Start = OS.tell(); |
| (void) Start; |
| |
| assert(F.getFileOffset() == Start && "Invalid file offset!"); |
| |
| // FIXME: Embed in fragments instead? |
| switch (F.getKind()) { |
| case MCFragment::FT_Align: { |
| MCAlignFragment &AF = cast<MCAlignFragment>(F); |
| uint64_t Count = AF.getFileSize() / AF.getValueSize(); |
| |
| // FIXME: This error shouldn't actually occur (the front end should emit |
| // multiple .align directives to enforce the semantics it wants), but is |
| // severe enough that we want to report it. How to handle this? |
| if (Count * AF.getValueSize() != AF.getFileSize()) |
| llvm_report_error("undefined .align directive, value size '" + |
| Twine(AF.getValueSize()) + |
| "' is not a divisor of padding size '" + |
| Twine(AF.getFileSize()) + "'"); |
| |
| for (uint64_t i = 0; i != Count; ++i) { |
| switch (AF.getValueSize()) { |
| default: |
| assert(0 && "Invalid size!"); |
| case 1: MOW.Write8 (uint8_t (AF.getValue())); break; |
| case 2: MOW.Write16(uint16_t(AF.getValue())); break; |
| case 4: MOW.Write32(uint32_t(AF.getValue())); break; |
| case 8: MOW.Write64(uint64_t(AF.getValue())); break; |
| } |
| } |
| break; |
| } |
| |
| case MCFragment::FT_Data: |
| OS << cast<MCDataFragment>(F).getContents().str(); |
| break; |
| |
| case MCFragment::FT_Fill: { |
| MCFillFragment &FF = cast<MCFillFragment>(F); |
| |
| if (!FF.getValue().isAbsolute()) |
| llvm_unreachable("FIXME: Not yet implemented!"); |
| int64_t Value = FF.getValue().getConstant(); |
| |
| for (uint64_t i = 0, e = FF.getCount(); i != e; ++i) { |
| switch (FF.getValueSize()) { |
| default: |
| assert(0 && "Invalid size!"); |
| case 1: MOW.Write8 (uint8_t (Value)); break; |
| case 2: MOW.Write16(uint16_t(Value)); break; |
| case 4: MOW.Write32(uint32_t(Value)); break; |
| case 8: MOW.Write64(uint64_t(Value)); break; |
| } |
| } |
| break; |
| } |
| |
| case MCFragment::FT_Org: { |
| MCOrgFragment &OF = cast<MCOrgFragment>(F); |
| |
| for (uint64_t i = 0, e = OF.getFileSize(); i != e; ++i) |
| MOW.Write8(uint8_t(OF.getValue())); |
| |
| break; |
| } |
| } |
| |
| assert(OS.tell() - Start == F.getFileSize()); |
| } |
| |
| /// WriteFileData - Write the \arg SD data to the output file. |
| static void WriteFileData(raw_ostream &OS, const MCSectionData &SD, |
| MachObjectWriter &MOW) { |
| uint64_t Start = OS.tell(); |
| (void) Start; |
| |
| for (MCSectionData::const_iterator it = SD.begin(), |
| ie = SD.end(); it != ie; ++it) |
| WriteFileData(OS, *it, MOW); |
| |
| assert(OS.tell() - Start == SD.getFileSize()); |
| } |
| |
| void MCAssembler::Finish() { |
| unsigned NumSections = Sections.size(); |
| |
| // Layout the sections and fragments. |
| uint64_t Offset = MachObjectWriter::getPrologSize32(NumSections); |
| uint64_t SectionDataSize = 0; |
| for (iterator it = begin(), ie = end(); it != ie; ++it) { |
| it->setFileOffset(Offset); |
| |
| LayoutSection(*it); |
| |
| Offset += it->getFileSize(); |
| SectionDataSize += it->getFileSize(); |
| } |
| |
| MachObjectWriter MOW(OS); |
| |
| // Write the prolog, starting with the header and load command... |
| MOW.WriteHeader32(NumSections); |
| MOW.WriteSegmentLoadCommand32(NumSections, SectionDataSize); |
| |
| // ... and then the section headers. |
| for (iterator it = begin(), ie = end(); it != ie; ++it) |
| MOW.WriteSection32(*it); |
| |
| // Finally, write the section data. |
| for (iterator it = begin(), ie = end(); it != ie; ++it) |
| WriteFileData(OS, *it, MOW); |
| |
| OS.flush(); |
| } |