✨ Add QIRSetAttributesAndMetadata Pass

[MatthiasReumann]

Changes

• ✨ Adds an QIRSetAttributesAndMetadata pass which sets the meta data of the QIR entry point function. Resolves 🐛 Invalid / Duplicated Metadata Produced By QIR Builder / Translation #1777.
• 🚛 Migrates QIRMetadata.h into the new pass file.
• ✨Calls the pass on qirbuilder.finalize() and after the cleanup pipeline.
• ✨Adds additional attribute checks to the IR-verifier.

Checklist

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• I have added migration instructions to the upgrade guide (if needed).
• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

If PR contains AI-assisted content:

• I have disclosed the use of AI tools in the PR description as per our AI Usage Guidelines.
• AI-assisted commits include an Assisted-by: [Model Name] via [Tool Name] footer.
• I confirm that I have personally reviewed and understood all AI-generated content, and accept full responsibility for it.

[codecov]

Codecov Report

❌ Patch coverage is 90.41667% with 23 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...lib/Dialect/QIR/Transforms/AttachQIRAttributes.cpp	93.2%	11 Missing ⚠️
mlir/lib/Support/IRVerification.cpp	70.2%	11 Missing ⚠️
mlir/lib/Compiler/CompilerPipeline.cpp	87.5%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[MatthiasReumann]

@coderabbitai full review

[coderabbitai]

Actionable comments posted: 3

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (3)

mlir/lib/Conversion/QCToQIR/QIRAdaptive/QCToQIRAdaptive.cpp (1)

475-483: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Documentation lists removed stage.

The class-level docstring still references "6. Set QIR metadata attributes" which has been removed from the implementation. The stage numbers in the docstring (1-8) don't match the actual implementation stages (1-7).

📝 Suggested fix

 * Conversion stages:
 * 1. Convert scf dialect to cf
-* 2. Cpmvert func dialect to LLVM
+* 2. Convert func dialect to LLVM
 * 3. Ensure proper block structure for QIR Adaptive Profile
 * 4. Add QIR initialization call
 * 5. Convert QC and memref operations to QIR calls
-* 6. Set QIR metadata attributes
-* 7. Convert arith and cf dialects to LLVM
-* 8. Reconcile unrealized casts
+* 6. Convert arith and cf dialects to LLVM
+* 7. Reconcile unrealized casts

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@mlir/lib/Conversion/QCToQIR/QIRAdaptive/QCToQIRAdaptive.cpp` around lines 475
- 483, The docstring in the QCToQIRAdaptive.cpp file describes eight conversion
stages but the implementation only contains seven stages. Update the comment
block by removing the line "6. Set QIR metadata attributes" and renumbering the
subsequent stage from "7. Convert arith and cf dialects to LLVM" to "6. Convert
arith and cf dialects to LLVM" and "8. Reconcile unrealized casts" to "7.
Reconcile unrealized casts" to ensure the documented stages match the actual
implementation.

mlir/lib/Conversion/QCToQIR/QIRBase/QCToQIRBase.cpp (1)

288-296: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Class-level docstring still lists removed metadata stage.

The class documentation lists "5. Set QIR metadata attributes" which has been removed from the implementation. Update the stage list to match the actual 6-stage implementation.

📝 Suggested fix

 * Conversion stages:
 * 1. Convert func dialect to LLVM
 * 2. Ensure proper block structure for QIR base profile
 * 3. Add QIR initialization call
 * 4. Convert QC operations to QIR calls
-* 5. Set QIR metadata attributes
-* 6. Convert arith and cf dialects to LLVM
-* 7. Reconcile unrealized casts
+* 5. Convert arith and cf dialects to LLVM
+* 6. Reconcile unrealized casts

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@mlir/lib/Conversion/QCToQIR/QIRBase/QCToQIRBase.cpp` around lines 288 - 296,
The class-level docstring in the conversion function lists a seven-stage
conversion process including "5. Set QIR metadata attributes", but this stage
has been removed from the actual implementation. Update the docstring to remove
stage 5 and renumber the remaining stages so that "Convert arith and cf dialects
to LLVM" becomes stage 5 and "Reconcile unrealized casts" becomes stage 6,
making the documented process match the actual six-stage implementation.

mlir/unittests/Conversion/QCToQIR/QCToQIRAdaptive/test_qc_to_qir_adaptive.cpp (1)

103-114: 🧹 Nitpick | 🔵 Trivial | ⚡ Quick win

Add explicit assertions for QIR metadata deduplication.

ProgramEquivalence cleans both program and reference with runQIRCleanupPipeline(..., true). A symmetric regression in cleanup (e.g., duplicated required_num_qubits / required_num_results on both sides) can still pass equivalence. Add direct post-cleanup assertions that these keys occur exactly once in entry-point passthrough metadata.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In
`@mlir/unittests/Conversion/QCToQIR/QCToQIRAdaptive/test_qc_to_qir_adaptive.cpp`
around lines 103 - 114, The test currently relies on ProgramEquivalence to
verify both programs match, but symmetric regressions (where duplicated metadata
appears on both sides) would still pass equivalence checks. After calling
runQIRCleanupPipeline on both program and reference (which occurs after line 103
and before line 114), add explicit assertions to verify that metadata
deduplication worked correctly. Specifically, add assertions to check that
metadata keys like required_num_qubits and required_num_results appear exactly
once in the entry-point passthrough metadata for both the program and reference
objects to catch any symmetric metadata duplication issues.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@mlir/lib/Dialect/QIR/Transforms/AttachQIRAttributes.cpp`:
- Around line 65-70: The runOnOperation method calls getMainFunction which can
return nullptr when no function with the entry_point attribute exists, but does
not check for null before passing the result to setMetadata, getAdaptive, or
getBase. Add a null check on the main variable immediately after the
getMainFunction call and return early from runOnOperation if main is nullptr to
prevent null pointer dereference.
- Around line 374-375: Fix the Doxygen comment for the getAdaptive method which
currently incorrectly states "QIR base profile compliant program" but should
state "QIR adaptive profile compliant program" since the method name and
functionality are related to the adaptive profile, not the base profile. Update
the comment text to accurately reflect that this method returns metadata for the
adaptive profile.
- Around line 247-255: In the classifyCondBrOp function, the call to
condition.getDefiningOp() can return nullptr when the condition is a block
argument rather than an operation result, and passing nullptr to dyn_cast will
cause a crash. Add a null check on the result of getDefiningOp() before
attempting the dyn_cast to LLVM::CallOp, and if it is null, handle that case
appropriately (the existing comment suggests returning true for non-measurement
conditions).

---

Outside diff comments:
In `@mlir/lib/Conversion/QCToQIR/QIRAdaptive/QCToQIRAdaptive.cpp`:
- Around line 475-483: The docstring in the QCToQIRAdaptive.cpp file describes
eight conversion stages but the implementation only contains seven stages.
Update the comment block by removing the line "6. Set QIR metadata attributes"
and renumbering the subsequent stage from "7. Convert arith and cf dialects to
LLVM" to "6. Convert arith and cf dialects to LLVM" and "8. Reconcile unrealized
casts" to "7. Reconcile unrealized casts" to ensure the documented stages match
the actual implementation.

In `@mlir/lib/Conversion/QCToQIR/QIRBase/QCToQIRBase.cpp`:
- Around line 288-296: The class-level docstring in the conversion function
lists a seven-stage conversion process including "5. Set QIR metadata
attributes", but this stage has been removed from the actual implementation.
Update the docstring to remove stage 5 and renumber the remaining stages so that
"Convert arith and cf dialects to LLVM" becomes stage 5 and "Reconcile
unrealized casts" becomes stage 6, making the documented process match the
actual six-stage implementation.

In
`@mlir/unittests/Conversion/QCToQIR/QCToQIRAdaptive/test_qc_to_qir_adaptive.cpp`:
- Around line 103-114: The test currently relies on ProgramEquivalence to verify
both programs match, but symmetric regressions (where duplicated metadata
appears on both sides) would still pass equivalence checks. After calling
runQIRCleanupPipeline on both program and reference (which occurs after line 103
and before line 114), add explicit assertions to verify that metadata
deduplication worked correctly. Specifically, add assertions to check that
metadata keys like required_num_qubits and required_num_results appear exactly
once in the entry-point passthrough metadata for both the program and reference
objects to catch any symmetric metadata duplication issues.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: bbb22f46-55eb-405d-af7d-6e976a1662b3

📥 Commits

Reviewing files that changed from the base of the PR and between 12cf546 and 026ba2c.

📒 Files selected for processing (21)

• CHANGELOG.md
• mlir/include/mlir/Conversion/QCToQIR/QIRCommon/QIRCommon.h
• mlir/include/mlir/Dialect/QIR/Builder/QIRProgramBuilder.h
• mlir/include/mlir/Dialect/QIR/Transforms/Passes.td
• mlir/include/mlir/Dialect/QIR/Utils/QIRMetadata.h
• mlir/include/mlir/Dialect/QIR/Utils/QIRUtils.h
• mlir/include/mlir/Support/Passes.h
• mlir/lib/Compiler/CMakeLists.txt
• mlir/lib/Compiler/CompilerPipeline.cpp
• mlir/lib/Conversion/QCToQIR/QIRAdaptive/QCToQIRAdaptive.cpp
• mlir/lib/Conversion/QCToQIR/QIRBase/QCToQIRBase.cpp
• mlir/lib/Conversion/QCToQIR/QIRCommon/QIRCommon.cpp
• mlir/lib/Dialect/QIR/Builder/QIRProgramBuilder.cpp
• mlir/lib/Dialect/QIR/Transforms/AttachQIRAttributes.cpp
• mlir/lib/Dialect/QIR/Utils/QIRUtils.cpp
• mlir/lib/Support/IRVerification.cpp
• mlir/lib/Support/Passes.cpp
• mlir/unittests/Compiler/test_compiler_pipeline.cpp
• mlir/unittests/Conversion/QCToQIR/QCToQIRAdaptive/test_qc_to_qir_adaptive.cpp
• mlir/unittests/Conversion/QCToQIR/QCToQIRBase/test_qc_to_qir_base.cpp
• mlir/unittests/Dialect/QIR/IR/test_qir_ir.cpp

💤 Files with no reviewable changes (4)

• mlir/include/mlir/Dialect/QIR/Utils/QIRMetadata.h
• mlir/include/mlir/Dialect/QIR/Utils/QIRUtils.h
• mlir/lib/Conversion/QCToQIR/QIRCommon/QIRCommon.cpp
• mlir/lib/Dialect/QIR/Utils/QIRUtils.cpp

[burgholzer]

This looks very clean! Nice work.
I just have one minor question and a typo left here.
Otherwise, this is good to go!

[burgholzer]

Good to go!