LC

Write an IR Pretty-Printer and Round-Trip Parser

medium7/8

Add Phi-Nodes to Your SSA IR Study LLVM IR: Compile C Code and Read the .ll Output

Language

Compiler

2.0s Limit 256MB

Implementation

Why This Matters

LLVM's textual IR (.ll files) is round-trippable by design, and that decision made the entire ecosystem debuggable: every optimization bug report is a before/after IR dump. FileCheck-based tests — thousands of them in LLVM's repo — only work because the printer and parser agree, which is the invariant you are building.

Hints

0 / 3 revealed

Validation Suite

main.c

Workspace 1.0

Your Task

Implement a pretty-printer and parser for your three-address code IR that support round-trip conversion.

Requirements

Pretty-Printer

Format instructions:
- Binary ops: result = arg1 op arg2
- Assignments: result = arg1
- Labels: label_name:
- Jumps: goto label
- Conditional jumps: if condition goto label
Add structure:
- Comments before each basic block
- Blank lines between blocks
- Consistent indentation
Output:
- Write to file or stdout
- Support human-readable format

Parser

Read instructions:
- Ignore comments (lines starting with #)
- Parse instruction format
- Handle labels (ending with :)
- Build IR data structures
Error handling:
- Detect invalid syntax
- Report line number of errors
- Handle missing operands
Validation:
- Check for required fields
- Validate operator types
- Ensure labels are defined

Round-Trip Test

Generate IR
Pretty-print to string
Parse string back to IR
Pretty-print again
Compare outputs

Success Criteria

Printer outputs human-readable IR
Parser reads printer output correctly
Round-trip test passes (output matches)
Handles all instruction types
Good error messages for invalid input