mlir-fold.nvim

Neovim plugin for automatically folding MLIR IR dump sections with beautiful display and crash trace preservation.

Features

• 🔍 Auto-detects MLIR IR dump markers - Works with any file containing IR dumps
• 📁 Automatic folding - Each IR dump section is foldable independently
• 🏷️ Beautiful fold display - Shows pass names (Before/After), line counts with diamond decorators
• ⚡ Zero configuration - Works out of the box
• 🚀 Optimized for large files - Fast performance even with huge log files
• 🎯 Only activates when needed - No overhead for non-MLIR files
• 🛡️ Error/crash preservation - Stack traces and error messages stay visible
• 🔄 Pass detection - Supports "Before" and "After" passes, including failed passes
• 📝 No file modifications - Pure read-only folding

Requirements

• Neovim >= 0.8
• No external dependencies. Be careful with other folding plugins that may conflict. E.g., disable nvim-ufo for MLIR files (see Tips & Troubleshooting)

Installation

lazy.nvim

{
  'hanhanW/mlir-fold.nvim',
  ft = 'mlir',
}

packer.nvim

use 'hanhanW/mlir-fold.nvim'

vim-plug

Plug 'hanhanW/mlir-fold.nvim'

Fold Commands (Standard Vim)

• zo - Open fold under cursor
• zc - Close fold under cursor
• zR - Open all folds
• zM - Close all folds
• zj - Jump to next fold
• zk - Jump to previous fold
• za - Toggle fold under cursor

Example Display

When you open an MLIR log file with IR dumps:

◆ IR Dump After MaterializeTargetDevicesPass (iree-hal-materialize-target-devices) ◆ 89 lines

[IR dump content FOLDED]

◆ IR Dump After ResolveDevicePromisesPass (iree-hal-resolve-device-promises) ◆ 87 lines

[IR dump content FOLDED]

iree-compile: ....: Assertion `false' failed.
Stack dump:
0.	Program arguments: build/tools/iree-compile ...
 #0 0x0000713fdbb0b2e8 llvm::sys::PrintStackTrace(...)
 #1 0x0000713fdbb08f70 llvm::sys::RunSignalHandlers(...)
[... stack frames remain visible ...]

How It Works

Folding Strategy

• Each IR dump section (from marker to next marker) is a fold
• Error messages and stack traces are never folded
• Fold level 1 (flat) - no nested folds

Detection Patterns

• IR dump markers: // -----// IR Dump (Before|After) ...
• Error messages: File path errors like /path/file.mlir:line:col: error:
• Stack traces: Stack dump:, #0 0x..., #1 0x..., etc.
• Compiler errors: iree-compile:, iree-opt:, mlir-opt:, etc.

Performance Optimizations

• ✅ Only triggers on .mlir files (zero overhead for other files)
• ✅ Pre-compiled regex patterns (no recompilation overhead)
• ✅ Simplified error detection with early exit strategy
• ✅ Optimized for files 10K+ lines

Supported Compiler Tools

The plugin detects and preserves errors from:

• iree-compile
• iree-opt
• mlir-opt
• Any tool following the pattern <tool>: error message

Tips & Troubleshooting

Using with nvim-ufo

If you use nvim-ufo, you should disable it for MLIR files to use mlir-fold.nvim's folding instead:

{
  'kevinhwang91/nvim-ufo',
  config = function()
    require('ufo').setup({
      provider_selector = function(bufnr, filetype, buftype)
        -- Disable ufo for MLIR files (use mlir-fold.nvim instead)
        if filetype == 'mlir' then
          return ''
        end
        return { 'treesitter', 'indent' }
      end,
    })
  end,
}

This ensures mlir-fold.nvim has full control over folding for MLIR files.