1 //===- llvm/MC/MCSPIRVObjectWriter.cpp - SPIR-V Object 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/MCAssembler.h"
10 #include "llvm/MC/MCSPIRVObjectWriter.h"
11 #include "llvm/MC/MCSection.h"
12 #include "llvm/MC/MCValue.h"
13 #include "llvm/Support/EndianStream.h"
14
15 using namespace llvm;
16
17 class SPIRVObjectWriter : public MCObjectWriter {
18 ::support::endian::Writer W;
19
20 /// The target specific SPIR-V writer instance.
21 std::unique_ptr<MCSPIRVObjectTargetWriter> TargetObjectWriter;
22
23 public:
SPIRVObjectWriter(std::unique_ptr<MCSPIRVObjectTargetWriter> MOTW,raw_pwrite_stream & OS)24 SPIRVObjectWriter(std::unique_ptr<MCSPIRVObjectTargetWriter> MOTW,
25 raw_pwrite_stream &OS)
26 : W(OS, support::little), TargetObjectWriter(std::move(MOTW)) {}
27
~SPIRVObjectWriter()28 ~SPIRVObjectWriter() override {}
29
30 private:
recordRelocation(MCAssembler & Asm,const MCAsmLayout & Layout,const MCFragment * Fragment,const MCFixup & Fixup,MCValue Target,uint64_t & FixedValue)31 void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout,
32 const MCFragment *Fragment, const MCFixup &Fixup,
33 MCValue Target, uint64_t &FixedValue) override {}
34
executePostLayoutBinding(MCAssembler & Asm,const MCAsmLayout & Layout)35 void executePostLayoutBinding(MCAssembler &Asm,
36 const MCAsmLayout &Layout) override {}
37
38 uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
39 void writeHeader(const MCAssembler &Asm);
40 };
41
writeHeader(const MCAssembler & Asm)42 void SPIRVObjectWriter::writeHeader(const MCAssembler &Asm) {
43 constexpr uint32_t MagicNumber = 0x07230203;
44
45 // TODO: set the version on a min-necessary basis (just like the translator
46 // does) requires some refactoring of MCAssembler::VersionInfoType.
47 constexpr uint32_t Major = 1;
48 constexpr uint32_t Minor = 0;
49 constexpr uint32_t VersionNumber = 0 | (Major << 16) | (Minor << 8);
50 // TODO: check if we could use anything other than 0 (spec allows).
51 constexpr uint32_t GeneratorMagicNumber = 0;
52 // TODO: do not hardcode this as well.
53 constexpr uint32_t Bound = 900;
54 constexpr uint32_t Schema = 0;
55
56 W.write<uint32_t>(MagicNumber);
57 W.write<uint32_t>(VersionNumber);
58 W.write<uint32_t>(GeneratorMagicNumber);
59 W.write<uint32_t>(Bound);
60 W.write<uint32_t>(Schema);
61 }
62
writeObject(MCAssembler & Asm,const MCAsmLayout & Layout)63 uint64_t SPIRVObjectWriter::writeObject(MCAssembler &Asm,
64 const MCAsmLayout &Layout) {
65 uint64_t StartOffset = W.OS.tell();
66 writeHeader(Asm);
67 for (const MCSection &S : Asm)
68 Asm.writeSectionData(W.OS, &S, Layout);
69 return W.OS.tell() - StartOffset;
70 }
71
72 std::unique_ptr<MCObjectWriter>
createSPIRVObjectWriter(std::unique_ptr<MCSPIRVObjectTargetWriter> MOTW,raw_pwrite_stream & OS)73 llvm::createSPIRVObjectWriter(std::unique_ptr<MCSPIRVObjectTargetWriter> MOTW,
74 raw_pwrite_stream &OS) {
75 return std::make_unique<SPIRVObjectWriter>(std::move(MOTW), OS);
76 }
77