[IR2Vec][llvm-ir2vec] Add support for reading from stdin

[svkeerthy]

Add support for reading LLVM IR from stdin in the llvm-ir2vec tool.

This allows usage of the tool in pipelines where LLVM IR is generated or transformed on-the-fly just like the other llvm tools. Useful in upcoming PRs.

(Tracking issue - #141817)

[svkeerthy]

• [IR2Vec] Add triplet generation utility script for vocabulary training #149215
• [IR2Vec][llvm-ir2vec] Revamp triplet generation and add entity mapping mode  #149214
• [IR2Vec][llvm-ir2vec] Add support for reading from stdin #149213 👈 (View in Graphite)
• [IR2Vec][NFC] Add helper methods for numeric ID mapping in Vocabulary #149212
• [IR2Vec] Adding documentation for llvm-ir2vec tool #148719
• [IR2Vec] Add embeddings mode to llvm-ir2vec tool #147844
• [IR2Vec] Add llvm-ir2vec tool for generating triplet embeddings #147842
• [NFC][IR2Vec] Exposing helpers in IR2Vec Vocabulary #147841
• [NFC][IR2Vec] Minor refactoring of opcode access in vocabulary #147585
• [IR2Vec] Restructuring Vocabulary #145119
• [IR2Vec] Add out-of-place arithmetic operators to Embedding class #145118
• [NFC][IR2Vec] Increasing tolerance in approximatelyEquals() of Embedding  #145117
• [IR2Vec] Simplifying creation of Embedder #143999
• [IR2Vec] Scale embeddings once in vocab analysis instead of repetitive scaling #143986
• [MLGO][IR2Vec] Integrating IR2Vec with MLInliner #143479 : 1 other dependent PR (#144139 )
• [IR2Vec] Consider only reachable BBs and non-debug instructions #143476
• [IR2Vec] Minor vocab changes and exposing weights #143200
• [IR2Vec] Exposing Embedding as an data type wrapped around std::vector<double> #143197
• main

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[boomanaiden154]

Nits at this point, otherwise LGTM.

[Copilot]

Pull Request Overview

Adds support for reading LLVM IR from stdin by allowing "-" as the positional input filename and updating the parsing logic.

• Changed InputFilename option to default to "-" and updated its description for stdin support
• Refactored main to introduce a placeholder for stdin handling and unconditionally call parseIRFile

Comments suppressed due to low confidence (1)

llvm/tools/llvm-ir2vec/llvm-ir2vec.cpp:54

• The new stdin support path isn't covered by existing tests. Consider adding unit or integration tests that pipe LLVM IR into stdin (using -) to verify the feature works end-to-end.

                  cl::init("-"), cl::cat(IR2VecToolCategory));

[svkeerthy]

Merge activity

• Jul 17, 8:36 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Jul 17, 8:41 PM UTC: Graphite rebased this pull request as part of a merge.
• Jul 17, 8:43 PM UTC: @svkeerthy merged this pull request with Graphite.

[boomanaiden154]

Should have thought of this during the review: You might want to add a test somewhere that checks this actually works.