1 //===- llvm/MC/MCDXContainerWriter.cpp - DXContainer Writer -----*- 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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/MC/MCDXContainerWriter.h" 10 #include "llvm/BinaryFormat/DXContainer.h" 11 #include "llvm/MC/MCAsmLayout.h" 12 #include "llvm/MC/MCAssembler.h" 13 #include "llvm/MC/MCContext.h" 14 #include "llvm/MC/MCSection.h" 15 #include "llvm/MC/MCValue.h" 16 #include "llvm/Support/Alignment.h" 17 #include "llvm/Support/EndianStream.h" 18 19 using namespace llvm; 20 21 MCDXContainerTargetWriter::~MCDXContainerTargetWriter() {} 22 23 namespace { 24 class DXContainerObjectWriter : public MCObjectWriter { 25 ::support::endian::Writer W; 26 27 /// The target specific DXContainer writer instance. 28 std::unique_ptr<MCDXContainerTargetWriter> TargetObjectWriter; 29 30 public: 31 DXContainerObjectWriter(std::unique_ptr<MCDXContainerTargetWriter> MOTW, 32 raw_pwrite_stream &OS) 33 : W(OS, support::little), TargetObjectWriter(std::move(MOTW)) {} 34 35 ~DXContainerObjectWriter() override {} 36 37 private: 38 void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout, 39 const MCFragment *Fragment, const MCFixup &Fixup, 40 MCValue Target, uint64_t &FixedValue) override {} 41 42 void executePostLayoutBinding(MCAssembler &Asm, 43 const MCAsmLayout &Layout) override {} 44 45 uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override; 46 }; 47 } // namespace 48 49 uint64_t DXContainerObjectWriter::writeObject(MCAssembler &Asm, 50 const MCAsmLayout &Layout) { 51 // Start the file size as the header plus the size of the part offsets. 52 // Presently DXContainer files usually contain 7-10 parts. Reserving space for 53 // 16 part offsets gives us a little room for growth. 54 llvm::SmallVector<uint64_t, 16> PartOffsets; 55 uint64_t PartOffset = 0; 56 for (const MCSection &Sec : Asm) { 57 uint64_t SectionSize = Layout.getSectionAddressSize(&Sec); 58 // Skip empty sections. 59 if (SectionSize == 0) 60 continue; 61 62 assert(SectionSize < std::numeric_limits<uint32_t>::max() && 63 "Section size too large for DXContainer"); 64 65 PartOffsets.push_back(PartOffset); 66 PartOffset += sizeof(dxbc::PartHeader) + SectionSize; 67 PartOffset = alignTo(PartOffset, Align(4ul)); 68 // The DXIL part also writes a program header, so we need to include its 69 // size when computing the offset for a part after the DXIL part. 70 if (Sec.getName() == "DXIL") 71 PartOffset += sizeof(dxbc::ProgramHeader); 72 } 73 assert(PartOffset < std::numeric_limits<uint32_t>::max() && 74 "Part data too large for DXContainer"); 75 76 uint64_t PartStart = 77 sizeof(dxbc::Header) + (PartOffsets.size() * sizeof(uint32_t)); 78 uint64_t FileSize = PartStart + PartOffset; 79 assert(FileSize < std::numeric_limits<uint32_t>::max() && 80 "File size too large for DXContainer"); 81 82 // Write the header. 83 W.write<char>({'D', 'X', 'B', 'C'}); 84 // Write 16-bytes of 0's for the hash. 85 W.OS.write_zeros(16); 86 // Write 1.0 for file format version. 87 W.write<uint16_t>(1u); 88 W.write<uint16_t>(0u); 89 // Write the file size. 90 W.write<uint32_t>(static_cast<uint32_t>(FileSize)); 91 // Write the number of parts. 92 W.write<uint32_t>(static_cast<uint32_t>(PartOffsets.size())); 93 // Write the offsets for the part headers for each part. 94 for (uint64_t Offset : PartOffsets) 95 W.write<uint32_t>(static_cast<uint32_t>(PartStart + Offset)); 96 97 for (const MCSection &Sec : Asm) { 98 uint64_t SectionSize = Layout.getSectionAddressSize(&Sec); 99 // Skip empty sections. 100 if (SectionSize == 0) 101 continue; 102 103 unsigned Start = W.OS.tell(); 104 // Write section header. 105 W.write<char>(ArrayRef<char>(Sec.getName().data(), 4)); 106 107 uint64_t PartSize = SectionSize; 108 109 if (Sec.getName() == "DXIL") 110 PartSize += sizeof(dxbc::ProgramHeader); 111 // DXContainer parts should be 4-byte aligned. 112 PartSize = alignTo(PartSize, Align(4)); 113 W.write<uint32_t>(static_cast<uint32_t>(PartSize)); 114 if (Sec.getName() == "DXIL") { 115 dxbc::ProgramHeader Header; 116 memset(reinterpret_cast<void *>(&Header), 0, sizeof(dxbc::ProgramHeader)); 117 118 const Triple &TT = Asm.getContext().getTargetTriple(); 119 VersionTuple Version = TT.getOSVersion(); 120 Header.MajorVersion = static_cast<uint8_t>(Version.getMajor()); 121 if (Version.getMinor()) 122 Header.MinorVersion = static_cast<uint8_t>(*Version.getMinor()); 123 if (TT.hasEnvironment()) 124 Header.ShaderKind = 125 static_cast<uint16_t>(TT.getEnvironment() - Triple::Pixel); 126 127 // The program header's size field is in 32-bit words. 128 Header.Size = (SectionSize + sizeof(dxbc::ProgramHeader) + 3) / 4; 129 memcpy(Header.Bitcode.Magic, "DXIL", 4); 130 Header.Bitcode.Offset = sizeof(dxbc::BitcodeHeader); 131 Header.Bitcode.Size = SectionSize; 132 if (sys::IsBigEndianHost) 133 Header.swapBytes(); 134 W.write<char>(ArrayRef<char>(reinterpret_cast<char *>(&Header), 135 sizeof(dxbc::ProgramHeader))); 136 } 137 Asm.writeSectionData(W.OS, &Sec, Layout); 138 unsigned Size = W.OS.tell() - Start; 139 W.OS.write_zeros(offsetToAlignment(Size, Align(4))); 140 } 141 return 0; 142 } 143 144 std::unique_ptr<MCObjectWriter> llvm::createDXContainerObjectWriter( 145 std::unique_ptr<MCDXContainerTargetWriter> MOTW, raw_pwrite_stream &OS) { 146 return std::make_unique<DXContainerObjectWriter>(std::move(MOTW), OS); 147 } 148