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[DirectX] Replace bitfield version in ProgramHeader. (#91797)

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Avoid using bitfield in dxbc::ProgramHeader.
It could potentially be read incorrectly on any host depending on the
compiler.

From [C++17's
[class.bit]](https://timsong-cpp.github.io/cppwp/n4659/class.bit#1)
> Bit-fields are packed into some addressable allocation unit. [ Note:
Bit-fields straddle allocation units on some machines and not on others.
Bit-fields are assigned right-to-left on some machines, left-to-right on
others.  — end note ]

For #91793
This commit is contained in:
Xiang Li 2024-05-11 18:16:22 -07:00 committed by GitHub
parent 0869204cff
commit f42117c851
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
5 changed files with 58 additions and 9 deletions
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8
llvm/include/llvm/BinaryFormat/DXContainer.h
View File

@ -119,8 +119,7 @@ struct BitcodeHeader {
};
struct ProgramHeader {
uint8_t MinorVersion : 4;
uint8_t MajorVersion : 4;
uint8_t Version;
uint8_t Unused;
uint16_t ShaderKind;
uint32_t Size; // Size in uint32_t words including this header.
@ -131,6 +130,11 @@ struct ProgramHeader {
sys::swapByteOrder(Size);
Bitcode.swapBytes();
}
uint8_t getMajorVersion() { return Version >> 4; }
uint8_t getMinorVersion() { return Version & 0xF; }
static uint8_t getVersion(uint8_t Major, uint8_t Minor) {
return (Major << 4) | Minor;
}
};
static_assert(sizeof(ProgramHeader) == 24, "ProgramHeader Size incorrect!");

8
llvm/lib/MC/MCDXContainerWriter.cpp
View File

@ -117,9 +117,11 @@ uint64_t DXContainerObjectWriter::writeObject(MCAssembler &Asm,
const Triple &TT = Asm.getContext().getTargetTriple();
VersionTuple Version = TT.getOSVersion();
Header.MajorVersion = static_cast<uint8_t>(Version.getMajor());
if (Version.getMinor())
Header.MinorVersion = static_cast<uint8_t>(*Version.getMinor());
uint8_t MajorVersion = static_cast<uint8_t>(Version.getMajor());
uint8_t MinorVersion =
static_cast<uint8_t>(Version.getMinor().value_or(0));
Header.Version =
dxbc::ProgramHeader::getVersion(MajorVersion, MinorVersion);
if (TT.hasEnvironment())
Header.ShaderKind =
static_cast<uint16_t>(TT.getEnvironment() - Triple::Pixel);

4
llvm/lib/ObjectYAML/DXContainerEmitter.cpp
View File

@ -131,8 +131,8 @@ void DXContainerWriter::writeParts(raw_ostream &OS) {
if (!P.Program)
continue;
dxbc::ProgramHeader Header;
Header.MajorVersion = P.Program->MajorVersion;
Header.MinorVersion = P.Program->MinorVersion;
Header.Version = dxbc::ProgramHeader::getVersion(P.Program->MajorVersion,
P.Program->MinorVersion);
Header.Unused = 0;
Header.ShaderKind = P.Program->ShaderKind;
memcpy(Header.Bitcode.Magic, "DXIL", 4);

4
llvm/tools/obj2yaml/dxcontainer2yaml.cpp
View File

@ -58,8 +58,8 @@ dumpDXContainer(MemoryBufferRef Source) {
assert(DXIL && "Since we are iterating and found a DXIL part, "
"this should never not have a value");
NewPart.Program = DXContainerYAML::DXILProgram{
DXIL->first.MajorVersion,
DXIL->first.MinorVersion,
DXIL->first.getMajorVersion(),
DXIL->first.getMinorVersion(),
DXIL->first.ShaderKind,
DXIL->first.Size,
DXIL->first.Bitcode.MajorVersion,

43
llvm/unittests/Object/DXContainerTest.cpp
View File

@ -174,6 +174,49 @@ TEST(DXCFile, ParseEmptyParts) {
}
}
// This test verify DXIL part are correctly parsed.
// This test is based on the binary output constructed from this yaml.
// --- !dxcontainer
// Header:
// Hash: [ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
// 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 ]
// Version:
// Major: 1
// Minor: 0
// PartCount: 1
// Parts:
// - Name: DXIL
// Size: 28
// Program:
// MajorVersion: 6
// MinorVersion: 5
// ShaderKind: 5
// Size: 8
// DXILMajorVersion: 1
// DXILMinorVersion: 5
// DXILSize: 4
// DXIL: [ 0x42, 0x43, 0xC0, 0xDE, ]
// ...
TEST(DXCFile, ParseDXILPart) {
uint8_t Buffer[] = {
0x44, 0x58, 0x42, 0x43, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
0x48, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00,
0x44, 0x58, 0x49, 0x4c, 0x1c, 0x00, 0x00, 0x00, 0x65, 0x00, 0x05, 0x00,
0x08, 0x00, 0x00, 0x00, 0x44, 0x58, 0x49, 0x4c, 0x05, 0x01, 0x00, 0x00,
0x10, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x42, 0x43, 0xc0, 0xde};
DXContainer C =
llvm::cantFail(DXContainer::create(getMemoryBuffer<116>(Buffer)));
EXPECT_EQ(C.getHeader().PartCount, 1u);
const std::optional<object::DXContainer::DXILData> &DXIL = C.getDXIL();
EXPECT_TRUE(DXIL.has_value());
dxbc::ProgramHeader Header = DXIL->first;
EXPECT_EQ(Header.getMajorVersion(), 6u);
EXPECT_EQ(Header.getMinorVersion(), 5u);
EXPECT_EQ(Header.ShaderKind, 5u);
EXPECT_EQ(Header.Size, 8u);
}
static Expected<DXContainer>
generateDXContainer(StringRef Yaml, SmallVectorImpl<char> &BinaryData) {
DXContainerYAML::Object Obj;