llvm/llvm-project

[Attributor] Cleanup and upstream `Attribute::MaxObjectSize`

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#179 opened on Mar 14, 2020

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Description

We introduced a new llvm::Attribute in the Attributor tutorial (https://youtu.be/HVvvCSSLiTw) which never made it out of the prototype stage: https://github.com/jdoerfert/llvm-project/tree/feature/max_obj_size

The meaning of the attribute is described in the tutorial along with the rational, what code is there, and what needs to be done (to some degree).

  • Write a short RFC for a the attribute and send it to llvm-dev
  • Create the attribute with all the pluming (taken from the prototype)
  • Extract the deduction code from the prototype, rebase it, cleanup and additional tests, put it up for review
  • Extract the alias analysis interaction code, rebase it, cleanup and additional tests, put it up for review
  • Determine if and how we can use assumed information of dereferenceability and max object size inside of AANoAlias.

Contributor guide

Research direction
Review the prototype branch (jdoerfert/llvm project feature/max obj size), understand the attribute design, and follow the steps: write an RFC to llvm dev, create the attribute with plumbing, extract and clean up deduction and alias analysis interaction code, and determine how to use assumed information in AANoAlias.
Tech stack
cpp
Domain
compilerstooling
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++LLVM internalsGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25