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