hakorune/docs/development/current/main/investigations

Investigations Folder

This folder contains investigation notes and analysis for debugging sessions.

Active Investigations

Phase 131-12: LLVM Wrong Result (Case C)

Status: ✅ Root cause identified Problem: LLVM backend returns wrong results for loop exit values Root Cause: vmap object identity mismatch between Pass A and Pass C

Key Documents:

1. phase131-12-case-c-llvm-wrong-result.md - Initial investigation scope
2. phase131-12-p1-vmap-identity-analysis.md - Detailed trace analysis
3. phase131-12-p1-trace-summary.md - Executive summary with fix recommendations

Quick Summary:

• Bug: Pass A deletes _current_vmap before Pass C runs
• Impact: Terminators use wrong vmap object, missing all Pass A writes
• Fix: Store vmap_cur in deferred_terminators tuple (Option 3)

Next Steps:

1. Implement Option 3 fix in block_lower.py
2. Add Fail-Fast check in instruction_lower.py
3. Verify with NYASH_LLVM_VMAP_TRACE=1
4. Run full test suite

Trace Environment Variables

Phase 131-12-P1 Traces

NYASH_LLVM_VMAP_TRACE=1    # Object identity and vmap keys tracing
NYASH_LLVM_USE_HARNESS=1   # Enable llvmlite harness
NYASH_LLVM_DUMP_IR=<path>  # Save LLVM IR to file

Investigation Workflow

1. Scope - Define problem and test case (phase131-12-case-c-*.md)
2. Trace - Add instrumentation and collect data (phase131-12-p1-vmap-identity-*.md)
3. Analysis - Identify root cause with evidence (phase131-12-p1-trace-summary.md)
4. Fix - Implement solution with validation
5. Document - Update investigation notes with results

Archive

Completed investigations are kept for reference and pattern recognition.

JoinIR Generalization Study (Historical)

• joinir-generalization-study.md（Phase 131–138 の状況と一般化案の相談用コンテキスト。SSOT は design/ を参照）