[mlir][spirv] Serializer produces incorrect generator metadata in SPIR-V header

[andfau-amd]

See KhronosGroup/SPIRV-Tools#5717 for more. Probably a trivial one-line fix, good low-hanging fruit for a newcomer?

[andfau-amd]

llvm-project/mlir/lib/Target/SPIRV/SPIRVBinaryUtils.cpp

Lines 38 to 57 in bbcb3d6

	// See "2.3. Physical Layout of a SPIR-V Module and Instruction" in the SPIR-V
	// spec for the definition of the binary module header.
	//
	// The first five words of a SPIR-V module must be:
	// +-------------------------------------------------------------------------+
	// | Magic number |
	// +-------------------------------------------------------------------------+
	// | Version number (bytes: 0 | major number | minor number | 0) |
	// +-------------------------------------------------------------------------+
	// | Generator magic number |
	// +-------------------------------------------------------------------------+
	// | Bound (all result <id>s in the module guaranteed to be less than it) |
	// +-------------------------------------------------------------------------+
	// | 0 (reserved for instruction schema) |
	// +-------------------------------------------------------------------------+
	header.push_back(spirv::kMagicNumber);
	header.push_back((majorVersion << 16) | (minorVersion << 8));
	header.push_back(kGeneratorNumber);
	header.push_back(idBound); // <id> bound
	header.push_back(0); // Schema (reserved word)

[andfau-amd]

https://github.com/KhronosGroup/SPIRV-Headers/blob/3c355ec439dcf821c50fb4660ef0e50d19ae2b63/include/spirv/spir-v.xml#L35-L50

[llvmbot]

@llvm/issue-subscribers-mlir-spirv

Author: Andrea 🦈 (andfau-amd)

See https://github.com/KhronosGroup/SPIRV-Tools/issues/5717 for more. Probably a trivial one-line fix, good low-hanging fruit for a newcomer?

[kuhar]

Nice catch @andfau-amd!

[llvmbot]

@llvm/issue-subscribers-bug

Author: Andrea 🦈 (andfau-amd)

See https://github.com/KhronosGroup/SPIRV-Tools/issues/5717 for more. Probably a trivial one-line fix, good low-hanging fruit for a newcomer?

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor has already been assigned to this issue. If you believe that no one is actually working on it despite an assignment, ping the person. After one week without a response, the assignee may be changed.
2. In the comments of this issue, request for it to be assigned to you, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Andrea Faulds (andfau-amd)

See https://github.com/KhronosGroup/SPIRV-Tools/issues/5717 for more. Probably a trivial one-line fix, good low-hanging fruit for a newcomer?