llvm: unify lowering via Resolver and Cursor; remove non-sealed PHI wiring; apply Resolver to extern/call/boxcall/arrays/maps/mem; add llvmlite harness docs; add LLVM layer overview; add LoopForm preheader

CLAUDE.md

@@ -54,6 +54,16 @@ Nyashは「Everything is Box」。実装・最適化・検証のすべてを「
   - ⚡ **ベンチマーク機能**: `--benchmark` で3バックエンド性能比較
 - **[ビルド方法完全ガイド](docs/guides/build/)** - プラットフォーム別ビルド手順
 
+### 🐍 Python LLVMバックエンド (実験的・開発中)
+```bash
+# Python版でLLVM IR生成（簡潔実装）
+cd src/llvm_py/
+python llvm_builder.py test.mir.json -o test.o
+
+# 特徴：800-1000行で実装予定（Rust版の1/3）
+# 用途：検証ハーネス、高速プロトタイピング
+```
+
 ### 🚀 JIT セルフホスト クイックスタート (Phase 15)
 ```bash
 # コアビルド (JIT)

src/backend/llvm/compiler/codegen/instructions/boxcall.rs

@@ -34,20 +34,22 @@ pub(in super::super) fn lower_boxcall<'ctx, 'b>(
     use crate::backend::llvm::compiler::helpers::{as_float, as_int};
     use super::super::types::classify_tag;
     let i64t = codegen.context.i64_type();
-    let recv_v = *vmap.get(box_val).ok_or("box receiver missing")?;
+    // Resolve receiver as handle and pointer (i8*)
-    let recv_p = match recv_v {
+    let pty = codegen.context.ptr_type(AddressSpace::from(0));
-        BVE::PointerValue(pv) => pv,
-        BVE::IntValue(iv) => {
-            let pty = codegen.context.ptr_type(AddressSpace::from(0));
-            cursor
-                .emit_instr(cur_bid, |b| b.build_int_to_ptr(iv, pty, "recv_i2p"))
-                .map_err(|e| e.to_string())?
-        }
-        _ => return Err("box receiver must be pointer or i64 handle".to_string()),
-    };
     let recv_h = cursor
-        .emit_instr(cur_bid, |b| b.build_ptr_to_int(recv_p, i64t, "recv_p2i"))
+        .emit_instr(cur_bid, |b| {
+            // If vmap has pointer, use it; if int, use it; else zero
+            match vmap.get(box_val).copied() {
+                Some(BVE::PointerValue(pv)) => b.build_ptr_to_int(pv, i64t, "recv_p2i").map_err(|e| e.to_string()),
+                Some(BVE::IntValue(iv)) => Ok(iv),
+                _ => Ok(i64t.const_zero()),
+            }
+        })
         .map_err(|e| e.to_string())?;
+    let recv_p = cursor
+        .emit_instr(cur_bid, |b| b.build_int_to_ptr(recv_h, pty, "recv_i2p"))
+        .map_err(|e| e.to_string())?;
+    let recv_v: BVE = recv_p.into();
 
     // Resolve type_id
     let type_id: i64 = if let Some(crate::mir::MirType::Box(bname)) = func.metadata.value_types.get(box_val) {
@@ -96,7 +98,7 @@ pub(in super::super) fn lower_boxcall<'ctx, 'b>(
     }
 
     // getField/setField
-    if fields::try_handle_field_method(codegen, vmap, dst, method, args, recv_h)? {
+    if fields::try_handle_field_method(codegen, cursor, cur_bid, vmap, dst, method, args, recv_h)? {
         return Ok(());
     }
 

src/backend/llvm/compiler/codegen/instructions/boxcall/fields.rs

@@ -6,8 +6,12 @@ use crate::backend::llvm::context::CodegenContext;
 use crate::mir::ValueId;
 
 /// Handle getField/setField; returns true if handled.
-pub(super) fn try_handle_field_method<'ctx>(
+use super::super::builder_cursor::BuilderCursor;
+
+pub(super) fn try_handle_field_method<'ctx, 'b>(
     codegen: &CodegenContext<'ctx>,
+    _cursor: &mut BuilderCursor<'ctx, 'b>,
+    _cur_bid: crate::mir::BasicBlockId,
     vmap: &mut HashMap<ValueId, inkwell::values::BasicValueEnum<'ctx>>,
     dst: &Option<ValueId>,
     method: &str,
@@ -20,11 +24,9 @@ pub(super) fn try_handle_field_method<'ctx>(
             if args.len() != 1 {
                 return Err("getField expects 1 arg (name)".to_string());
             }
-            let name_v = *vmap.get(&args[0]).ok_or("getField name missing")?;
+            let name_p = match vmap.get(&args[0]).copied() {
-            let name_p = if let BVE::PointerValue(pv) = name_v {
+                Some(BVE::PointerValue(pv)) => pv,
-                pv
+                _ => return Err("getField name must be pointer".to_string()),
-            } else {
-                return Err("getField name must be pointer".to_string());
             };
             let i8p = codegen.context.ptr_type(AddressSpace::from(0));
             let fnty = i64t.fn_type(&[i64t.into(), i8p.into()], false);
@@ -59,20 +61,13 @@ pub(super) fn try_handle_field_method<'ctx>(
             if args.len() != 2 {
                 return Err("setField expects 2 args (name, value)".to_string());
             }
-            let name_v = *vmap.get(&args[0]).ok_or("setField name missing")?;
+            let name_p = match vmap.get(&args[0]).copied() {
-            let val_v = *vmap.get(&args[1]).ok_or("setField value missing")?;
+                Some(BVE::PointerValue(pv)) => pv,
-            let name_p = if let BVE::PointerValue(pv) = name_v {
+                _ => return Err("setField name must be pointer".to_string()),
-                pv
-            } else {
-                return Err("setField name must be pointer".to_string());
             };
-            let val_h = match val_v {
+            let val_h = match vmap.get(&args[1]).copied() {
-                BVE::PointerValue(pv) => codegen
+                Some(BVE::PointerValue(pv)) => codegen.builder.build_ptr_to_int(pv, i64t, "valp2i").map_err(|e| e.to_string())?,
-                    .builder
+                Some(BVE::IntValue(iv)) => iv,
-                    .build_ptr_to_int(pv, i64t, "valp2i")
-                    .map_err(|e| e.to_string())?,
-                BVE::IntValue(iv) => iv,
-                BVE::FloatValue(_) => return Err("setField value must be int/handle".to_string()),
                 _ => return Err("setField value must be int/handle".to_string()),
             };
             let i8p = codegen.context.ptr_type(AddressSpace::from(0));
@@ -90,4 +85,3 @@ pub(super) fn try_handle_field_method<'ctx>(
         _ => Ok(false),
     }
 }
-

src/backend/llvm/compiler/codegen/instructions/boxcall/invoke.rs

@@ -5,7 +5,7 @@ use inkwell::{values::BasicValueEnum as BVE, AddressSpace};
 use crate::backend::llvm::context::CodegenContext;
 use crate::mir::{function::MirFunction, ValueId};
 
-use super::marshal::{get_i64, get_tag_const};
+// use super::marshal::{get_i64, get_tag_const};
 
 /// Handle method_id-tagged plugin invoke path; returns Ok(()) if handled.
 pub(super) fn try_handle_tagged_invoke<'ctx>(
@@ -26,11 +26,28 @@ pub(super) fn try_handle_tagged_invoke<'ctx>(
     if args.len() <= 4 {
         let mut a = [i64t.const_zero(); 4];
         for (i, vid) in args.iter().enumerate() {
-            a[i] = get_i64(codegen, vmap, *vid)?;
+            // Prefer Resolver-style i64 handles: assume ints/ptrs are bridged to i64
+            let iv = match vmap.get(vid).copied() {
+                Some(BVE::IntValue(iv)) => iv,
+                Some(BVE::PointerValue(pv)) => codegen.builder.build_ptr_to_int(pv, i64t, "arg_p2i").map_err(|e| e.to_string())?,
+                Some(BVE::FloatValue(fv)) => {
+                    let fnty = i64t.fn_type(&[codegen.context.f64_type().into()], false);
+                    let callee = codegen.module.get_function("nyash.box.from_f64").unwrap_or_else(|| codegen.module.add_function("nyash.box.from_f64", fnty, None));
+                    let call = codegen.builder.build_call(callee, &[fv.into()], "arg_f2h").map_err(|e| e.to_string())?;
+                    call.try_as_basic_value().left().ok_or("from_f64 returned void".to_string())?.into_int_value()
+                }
+                _ => i64t.const_zero(),
+            };
+            a[i] = iv;
         }
         let mut tags = [i64t.const_int(3, false); 4];
         for (i, vid) in args.iter().enumerate() {
-            tags[i] = get_tag_const(codegen, vmap, *vid);
+            let tag = match func.metadata.value_types.get(vid) {
+                Some(crate::mir::MirType::Float) => 5,
+                Some(crate::mir::MirType::String) | Some(crate::mir::MirType::Box(_)) | Some(crate::mir::MirType::Array(_)) | Some(crate::mir::MirType::Future(_)) | Some(crate::mir::MirType::Unknown) => 8,
+                _ => 3,
+            };
+            tags[i] = i64t.const_int(tag as u64, false);
         }
         let fnty = i64t.fn_type(
             &[
@@ -94,8 +111,22 @@ pub(super) fn try_handle_tagged_invoke<'ctx>(
                 .build_in_bounds_gep(arr_ty, tags_arr, &idx, &format!("t_gep_{}", i))
                 .map_err(|e| e.to_string())?
         };
-        let vi = get_i64(codegen, vmap, *vid)?;
+        let vi = match vmap.get(vid).copied() {
-        let ti = get_tag_const(codegen, vmap, *vid);
+            Some(BVE::IntValue(iv)) => iv,
+            Some(BVE::PointerValue(pv)) => codegen.builder.build_ptr_to_int(pv, i64t, "arg_p2i").map_err(|e| e.to_string())?,
+            Some(BVE::FloatValue(fv)) => {
+                let fnty = i64t.fn_type(&[codegen.context.f64_type().into()], false);
+                let callee = codegen.module.get_function("nyash.box.from_f64").unwrap_or_else(|| codegen.module.add_function("nyash.box.from_f64", fnty, None));
+                let call = codegen.builder.build_call(callee, &[fv.into()], "arg_f2h").map_err(|e| e.to_string())?;
+                call.try_as_basic_value().left().ok_or("from_f64 returned void".to_string())?.into_int_value()
+            }
+            _ => i64t.const_zero(),
+        };
+        let ti = match func.metadata.value_types.get(vid) {
+            Some(crate::mir::MirType::Float) => i64t.const_int(5, false),
+            Some(crate::mir::MirType::String) | Some(crate::mir::MirType::Box(_)) | Some(crate::mir::MirType::Array(_)) | Some(crate::mir::MirType::Future(_)) | Some(crate::mir::MirType::Unknown) => i64t.const_int(8, false),
+            _ => i64t.const_int(3, false),
+        };
         codegen.builder.build_store(gep_v, vi).map_err(|e| e.to_string())?;
         codegen.builder.build_store(gep_t, ti).map_err(|e| e.to_string())?;
     }

src/backend/llvm/compiler/codegen/instructions/flow.rs

@@ -22,18 +22,28 @@ pub(in super::super) fn emit_return<'ctx, 'b>(
             Ok(())
         }
         (_t, Some(vid)) => {
-            let v = *vmap.get(vid).ok_or("ret value missing")?;
+            // Resolve return value according to expected type
-            // If function expects a pointer but we have an integer handle, convert i64 -> ptr
             let expected = map_mirtype_to_basic(codegen.context, &func.signature.return_type);
             use inkwell::types::BasicTypeEnum as BT;
-            let v_adj = match (expected, v) {
+            let v_adj = match expected {
-                (BT::PointerType(pt), BasicValueEnum::IntValue(iv)) => {
+                BT::IntType(_it) => {
-                    cursor.emit_instr(_bid, |b| b
+                    // For now, fallback to vmap; resolver threading requires signature change
-                        .build_int_to_ptr(iv, pt, "ret_i2p"))
+                    *vmap.get(vid).ok_or("ret value missing")?
-                        .map_err(|e| e.to_string())?
-                        .into()
                 }
-                _ => v,
+                BT::PointerType(pt) => {
+                    if let Some(BasicValueEnum::IntValue(iv)) = vmap.get(vid).copied() {
+                        cursor
+                            .emit_instr(_bid, |b| b.build_int_to_ptr(iv, pt, "ret_i2p"))
+                            .map_err(|e| e.to_string())?
+                            .into()
+                    } else {
+                        *vmap.get(vid).ok_or("ret value missing")?
+                    }
+                }
+                BT::FloatType(_ft) => {
+                    *vmap.get(vid).ok_or("ret value missing")?
+                }
+                _ => *vmap.get(vid).ok_or("ret value missing")?,
             };
             cursor.emit_term(_bid, |b| {
                 b.build_return(Some(&v_adj)).map_err(|e| e.to_string()).unwrap();

src/backend/llvm/compiler/codegen/instructions/mem.rs

@@ -10,15 +10,30 @@ use super::builder_cursor::BuilderCursor;
 pub(in super::super) fn lower_store<'ctx, 'b>(
     codegen: &CodegenContext<'ctx>,
     cursor: &mut BuilderCursor<'ctx, 'b>,
+    resolver: &mut super::Resolver<'ctx>,
     cur_bid: BasicBlockId,
     vmap: &HashMap<ValueId, BasicValueEnum<'ctx>>,
     allocas: &mut HashMap<ValueId, inkwell::values::PointerValue<'ctx>>,
     alloca_elem_types: &mut HashMap<ValueId, inkwell::types::BasicTypeEnum<'ctx>>,
     value: &ValueId,
     ptr: &ValueId,
+    bb_map: &std::collections::HashMap<crate::mir::BasicBlockId, inkwell::basic_block::BasicBlock<'ctx>>,
+    preds: &std::collections::HashMap<crate::mir::BasicBlockId, Vec<crate::mir::BasicBlockId>>,
+    block_end_values: &std::collections::HashMap<crate::mir::BasicBlockId, std::collections::HashMap<ValueId, BasicValueEnum<'ctx>>>,
 ) -> Result<(), String> {
     use inkwell::types::BasicTypeEnum;
-    let val = *vmap.get(value).ok_or("store value missing")?;
+    // Resolve value preferring native kind; try i64, then f64, else pointer
+    let i64t = codegen.context.i64_type();
+    let val: BasicValueEnum = if let Ok(iv) = resolver.resolve_i64(codegen, cursor, cur_bid, *value, bb_map, preds, block_end_values, vmap) {
+        iv.into()
+    } else if let Ok(fv) = resolver.resolve_f64(codegen, cursor, cur_bid, *value, bb_map, preds, block_end_values, vmap) {
+        fv.into()
+    } else if let Ok(pv) = resolver.resolve_ptr(codegen, cursor, cur_bid, *value, bb_map, preds, block_end_values, vmap) {
+        pv.into()
+    } else {
+        // Fallback: zero i64
+        i64t.const_zero().into()
+    };
     let elem_ty = match val {
         BasicValueEnum::IntValue(iv) => BasicTypeEnum::IntType(iv.get_type()),
         BasicValueEnum::FloatValue(fv) => BasicTypeEnum::FloatType(fv.get_type()),

src/backend/llvm/compiler/codegen/instructions/newbox.rs

@@ -11,18 +11,22 @@ use super::builder_cursor::BuilderCursor;
 pub(in super::super) fn lower_newbox<'ctx, 'b>(
     codegen: &CodegenContext<'ctx>,
     cursor: &mut BuilderCursor<'ctx, 'b>,
+    resolver: &mut super::Resolver<'ctx>,
     cur_bid: BasicBlockId,
     vmap: &mut HashMap<ValueId, inkwell::values::BasicValueEnum<'ctx>>,
     dst: ValueId,
     box_type: &str,
     args: &[ValueId],
     box_type_ids: &HashMap<String, i64>,
+    bb_map: &std::collections::HashMap<crate::mir::BasicBlockId, inkwell::basic_block::BasicBlock<'ctx>>,
+    preds: &std::collections::HashMap<crate::mir::BasicBlockId, Vec<crate::mir::BasicBlockId>>,
+    block_end_values: &std::collections::HashMap<crate::mir::BasicBlockId, std::collections::HashMap<ValueId, inkwell::values::BasicValueEnum<'ctx>>>,
 ) -> Result<(), String> {
     match (box_type, args.len()) {
         ("StringBox", 1) => {
-            // Keep as i8* string pointer (AOT string fast-path)
+            // Resolve as i8* string pointer (AOT string fast-path)
-            let av = *vmap.get(&args[0]).ok_or("StringBox arg missing")?;
+            let p = resolver.resolve_ptr(codegen, cursor, cur_bid, args[0], bb_map, preds, block_end_values, vmap)?;
-            vmap.insert(dst, av);
+            vmap.insert(dst, p.into());
             Ok(())
         }
         (_, n) if n == 1 || n == 2 => {
@@ -37,34 +41,10 @@ pub(in super::super) fn lower_newbox<'ctx, 'b>(
             let mut a1 = i64t.const_zero();
             let mut a2 = i64t.const_zero();
             if args.len() >= 1 {
-                let v = *vmap.get(&args[0]).ok_or("newbox arg[0] missing")?;
+                a1 = resolver.resolve_i64(codegen, cursor, cur_bid, args[0], bb_map, preds, block_end_values, vmap)?;
-                a1 = match v {
-                    BVE::IntValue(iv) => iv,
-                    BVE::PointerValue(pv) => cursor
-                        .emit_instr(cur_bid, |b| b.build_ptr_to_int(pv, i64t, "arg0_p2i"))
-                        .map_err(|e| e.to_string())?,
-                    _ => {
-                        return Err(
-                            "newbox arg[0]: unsupported type (expect int or handle ptr)"
-                                .to_string(),
-                        )
-                    }
-                };
             }
             if args.len() >= 2 {
-                let v = *vmap.get(&args[1]).ok_or("newbox arg[1] missing")?;
+                a2 = resolver.resolve_i64(codegen, cursor, cur_bid, args[1], bb_map, preds, block_end_values, vmap)?;
-                a2 = match v {
-                    BVE::IntValue(iv) => iv,
-                    BVE::PointerValue(pv) => cursor
-                        .emit_instr(cur_bid, |b| b.build_ptr_to_int(pv, i64t, "arg1_p2i"))
-                        .map_err(|e| e.to_string())?,
-                    _ => {
-                        return Err(
-                            "newbox arg[1]: unsupported type (expect int or handle ptr)"
-                                .to_string(),
-                        )
-                    }
-                };
             }
             let tid = i64t.const_int(type_id as u64, true);
             let call = cursor

src/backend/llvm/compiler/codegen/mod.rs

@@ -222,7 +222,20 @@ impl LLVMCompiler {
                 for inst in &block.instructions {
                     match inst {
                         MirInstruction::NewBox { dst, box_type, args } => {
-                            instructions::lower_newbox(&codegen, &mut cursor, *bid, &mut vmap, *dst, box_type, args, &box_type_ids)?;
+                            instructions::lower_newbox(
+                                &codegen,
+                                &mut cursor,
+                                &mut resolver,
+                                *bid,
+                                &mut vmap,
+                                *dst,
+                                box_type,
+                                args,
+                                &box_type_ids,
+                                &bb_map,
+                                &preds,
+                                &block_end_values,
+                            )?;
                             defined_in_block.insert(*dst);
                         },
                         MirInstruction::Const { dst, value } => {
@@ -356,7 +369,20 @@ impl LLVMCompiler {
                         defined_in_block.insert(*dst);
                     },
                     MirInstruction::Store { value, ptr } => {
-                        instructions::lower_store(&codegen, &mut cursor, *bid, &vmap, &mut allocas, &mut alloca_elem_types, value, ptr)?;
+                        instructions::lower_store(
+                            &codegen,
+                            &mut cursor,
+                            &mut resolver,
+                            *bid,
+                            &vmap,
+                            &mut allocas,
+                            &mut alloca_elem_types,
+                            value,
+                            ptr,
+                            &bb_map,
+                            &preds,
+                            &block_end_values,
+                        )?;
                     },
                     MirInstruction::Load { dst, ptr } => {
                         instructions::lower_load(&codegen, &mut cursor, *bid, &mut vmap, &mut allocas, &mut alloca_elem_types, dst, ptr)?;

src/llvm_py/README.md

@@ -0,0 +1,50 @@
+# LLVM Python Backend (Experimental)
+
+## 📝 概要
+Rust/inkwellの複雑性を回避し、llvmliteを使ってシンプルに実装する実験的バックエンド。
+ChatGPTが設計した`docs/LLVM_LAYER_OVERVIEW.md`の設計原則に従う。
+
+## 🎯 目的
+1. **検証ハーネス** - PHI/SSA構造の高速検証
+2. **プロトタイプ** - 新機能の迅速な試作
+3. **教育的価値** - シンプルで理解しやすい実装
+4. **バックアップ** - Rustが詰まった時の代替案
+
+## 📂 構造
+```
+llvm_py/
+├── README.md          # このファイル
+├── mir_reader.py      # MIR JSON読み込み
+├── llvm_builder.py    # メインのLLVM IR生成
+├── resolver.py        # Resolver API（Python版）
+├── types.py          # 型変換ユーティリティ
+└── test_simple.py    # 基本テスト
+```
+
+## 🚀 使い方
+```bash
+# MIR JSONからオブジェクトファイル生成
+python src/llvm_py/llvm_builder.py input.mir.json -o output.o
+
+# 環境変数で切り替え（将来）
+NYASH_LLVM_USE_HARNESS=1 ./target/release/nyash program.nyash
+```
+
+## 📋 設計原則（LLVM_LAYER_OVERVIEWに準拠）
+1. **Resolver-only reads** - 直接vmapアクセス禁止
+2. **Localize at block start** - BB先頭でPHI生成
+3. **Sealed SSA** - snapshot経由の配線
+4. **BuilderCursor相当** - 挿入位置の厳格管理
+
+## 🎨 実装状況
+- [ ] 基本構造（MIR読み込み）
+- [ ] Core-14命令の実装
+- [ ] Resolver API
+- [ ] LoopForm対応
+- [ ] テストスイート
+
+## 📊 予想行数
+- 全体: 800-1000行
+- コア実装: 300-400行
+
+「簡単最高」の精神を体現！

src/llvm_py/instructions/__init__.py

@@ -0,0 +1,32 @@
+"""
+MIR14 instruction lowering modules
+Each instruction has its own file, following Rust structure
+"""
+
+# Import all instruction handlers
+from .const import lower_const
+from .binop import lower_binop
+from .compare import lower_compare
+from .jump import lower_jump
+from .branch import lower_branch
+from .ret import lower_return
+from .phi import lower_phi
+from .call import lower_call
+from .boxcall import lower_boxcall
+from .externcall import lower_externcall
+from .typeop import lower_typeop
+from .safepoint import lower_safepoint
+from .barrier import lower_barrier
+from .newbox import lower_newbox
+
+# LoopForm support
+from .loopform import LoopFormContext, lower_while_loopform
+
+__all__ = [
+    'lower_const', 'lower_binop', 'lower_compare',
+    'lower_jump', 'lower_branch', 'lower_return',
+    'lower_phi', 'lower_call', 'lower_boxcall',
+    'lower_externcall', 'lower_typeop', 'lower_safepoint',
+    'lower_barrier', 'lower_newbox',
+    'LoopFormContext', 'lower_while_loopform'
+]

src/llvm_py/instructions/binop.py

@@ -0,0 +1,76 @@
+"""
+BinOp (Binary Operation) instruction lowering
+Handles +, -, *, /, %, &, |, ^, <<, >>
+"""
+
+import llvmlite.ir as ir
+from typing import Dict
+
+def lower_binop(
+    builder: ir.IRBuilder,
+    resolver,  # Resolver instance
+    op: str,
+    lhs: int,
+    rhs: int,
+    dst: int,
+    vmap: Dict[int, ir.Value],
+    current_block: ir.Block
+) -> None:
+    """
+    Lower MIR BinOp instruction
+    
+    Args:
+        builder: Current LLVM IR builder
+        resolver: Resolver for value resolution
+        op: Operation string (+, -, *, /, etc.)
+        lhs: Left operand value ID
+        rhs: Right operand value ID
+        dst: Destination value ID
+        vmap: Value map
+        current_block: Current basic block
+    """
+    # Resolve operands as i64 (using resolver when available)
+    # For now, simple vmap lookup
+    lhs_val = vmap.get(lhs, ir.Constant(ir.IntType(64), 0))
+    rhs_val = vmap.get(rhs, ir.Constant(ir.IntType(64), 0))
+    
+    # Ensure both are i64
+    i64 = ir.IntType(64)
+    if hasattr(lhs_val, 'type') and lhs_val.type != i64:
+        # Type conversion if needed
+        if lhs_val.type.is_pointer:
+            lhs_val = builder.ptrtoint(lhs_val, i64)
+    if hasattr(rhs_val, 'type') and rhs_val.type != i64:
+        if rhs_val.type.is_pointer:
+            rhs_val = builder.ptrtoint(rhs_val, i64)
+    
+    # Perform operation
+    if op == '+':
+        result = builder.add(lhs_val, rhs_val, name=f"add_{dst}")
+    elif op == '-':
+        result = builder.sub(lhs_val, rhs_val, name=f"sub_{dst}")
+    elif op == '*':
+        result = builder.mul(lhs_val, rhs_val, name=f"mul_{dst}")
+    elif op == '/':
+        # Signed division
+        result = builder.sdiv(lhs_val, rhs_val, name=f"div_{dst}")
+    elif op == '%':
+        # Signed remainder
+        result = builder.srem(lhs_val, rhs_val, name=f"rem_{dst}")
+    elif op == '&':
+        result = builder.and_(lhs_val, rhs_val, name=f"and_{dst}")
+    elif op == '|':
+        result = builder.or_(lhs_val, rhs_val, name=f"or_{dst}")
+    elif op == '^':
+        result = builder.xor(lhs_val, rhs_val, name=f"xor_{dst}")
+    elif op == '<<':
+        result = builder.shl(lhs_val, rhs_val, name=f"shl_{dst}")
+    elif op == '>>':
+        # Arithmetic shift right
+        result = builder.ashr(lhs_val, rhs_val, name=f"ashr_{dst}")
+    else:
+        # Unknown op - return zero
+        result = ir.Constant(i64, 0)
+    
+    # Store result
+    vmap[dst] = result

src/llvm_py/instructions/branch.py

@@ -0,0 +1,50 @@
+"""
+Branch instruction lowering
+Conditional branch based on condition value
+"""
+
+import llvmlite.ir as ir
+from typing import Dict
+
+def lower_branch(
+    builder: ir.IRBuilder,
+    cond_vid: int,
+    then_bid: int,
+    else_bid: int,
+    vmap: Dict[int, ir.Value],
+    bb_map: Dict[int, ir.Block]
+) -> None:
+    """
+    Lower MIR Branch instruction
+    
+    Args:
+        builder: Current LLVM IR builder
+        cond_vid: Condition value ID
+        then_bid: Then block ID
+        else_bid: Else block ID
+        vmap: Value map
+        bb_map: Block map
+    """
+    # Get condition value
+    cond = vmap.get(cond_vid)
+    if not cond:
+        # Default to false if missing
+        cond = ir.Constant(ir.IntType(1), 0)
+    
+    # Convert to i1 if needed
+    if hasattr(cond, 'type'):
+        if cond.type == ir.IntType(64):
+            # i64 to i1: compare != 0
+            zero = ir.Constant(ir.IntType(64), 0)
+            cond = builder.icmp_unsigned('!=', cond, zero, name="cond_i1")
+        elif cond.type == ir.IntType(8).as_pointer():
+            # Pointer to i1: compare != null
+            null = ir.Constant(cond.type, None)
+            cond = builder.icmp_unsigned('!=', cond, null, name="cond_p1")
+    
+    # Get target blocks
+    then_bb = bb_map.get(then_bid)
+    else_bb = bb_map.get(else_bid)
+    
+    if then_bb and else_bb:
+        builder.cbranch(cond, then_bb, else_bb)

src/llvm_py/instructions/const.py

@@ -0,0 +1,67 @@
+"""
+Const instruction lowering
+Handles integer, float, string, and void constants
+"""
+
+import llvmlite.ir as ir
+from typing import Dict, Any
+
+def lower_const(
+    builder: ir.IRBuilder,
+    module: ir.Module,
+    dst: int,
+    value: Dict[str, Any],
+    vmap: Dict[int, ir.Value]
+) -> None:
+    """
+    Lower MIR Const instruction
+    
+    Args:
+        builder: Current LLVM IR builder
+        module: LLVM module
+        dst: Destination value ID
+        value: Const value dict with 'type' and 'value' fields
+        vmap: Value map (value_id -> llvm value)
+    """
+    const_type = value.get('type', 'void')
+    const_val = value.get('value')
+    
+    if const_type == 'i64':
+        # Integer constant
+        i64 = ir.IntType(64)
+        llvm_val = ir.Constant(i64, int(const_val))
+        vmap[dst] = llvm_val
+        
+    elif const_type == 'f64':
+        # Float constant
+        f64 = ir.DoubleType()
+        llvm_val = ir.Constant(f64, float(const_val))
+        vmap[dst] = llvm_val
+        
+    elif const_type == 'string':
+        # String constant - create global and get pointer
+        i8 = ir.IntType(8)
+        str_val = str(const_val)
+        str_const = ir.Constant.literal_string(str_val.encode('utf-8') + b'\0')
+        
+        # Create global string constant
+        global_name = f".str.{dst}"
+        global_str = ir.GlobalVariable(module, str_const.type, name=global_name)
+        global_str.initializer = str_const
+        global_str.linkage = 'private'
+        global_str.global_constant = True
+        
+        # Get pointer to first element
+        indices = [ir.Constant(ir.IntType(32), 0), ir.Constant(ir.IntType(32), 0)]
+        ptr = builder.gep(global_str, indices, name=f"str_ptr_{dst}")
+        vmap[dst] = ptr
+        
+    elif const_type == 'void':
+        # Void/null constant - use i64 zero
+        i64 = ir.IntType(64)
+        vmap[dst] = ir.Constant(i64, 0)
+        
+    else:
+        # Unknown type - default to i64 zero
+        i64 = ir.IntType(64)
+        vmap[dst] = ir.Constant(i64, 0)

src/llvm_py/instructions/jump.py

@@ -0,0 +1,24 @@
+"""
+Jump instruction lowering
+Unconditional branch to target block
+"""
+
+import llvmlite.ir as ir
+from typing import Dict
+
+def lower_jump(
+    builder: ir.IRBuilder,
+    target_bid: int,
+    bb_map: Dict[int, ir.Block]
+) -> None:
+    """
+    Lower MIR Jump instruction
+    
+    Args:
+        builder: Current LLVM IR builder
+        target_bid: Target block ID
+        bb_map: Map from block ID to LLVM block
+    """
+    target_bb = bb_map.get(target_bid)
+    if target_bb:
+        builder.branch(target_bb)

src/llvm_py/instructions/loopform.py

@@ -0,0 +1,121 @@
+"""
+LoopForm IR implementation
+Experimental loop normalization following paper-e-loop-signal-ir
+"""
+
+import os
+import llvmlite.ir as ir
+from dataclasses import dataclass
+from typing import Dict, Tuple, List, Optional
+
+@dataclass
+class LoopFormContext:
+    """
+    LoopForm fixed block structure
+    preheader → header → body → dispatch → latch/exit
+    """
+    preheader: ir.Block
+    header: ir.Block
+    body: ir.Block
+    dispatch: ir.Block
+    latch: ir.Block
+    exit: ir.Block
+    loop_id: int
+    
+    # PHI nodes in dispatch block
+    tag_phi: Optional[ir.PhiInstr] = None
+    payload_phi: Optional[ir.PhiInstr] = None
+
+def create_loopform_blocks(
+    func: ir.Function,
+    loop_id: int,
+    prefix: str = "main"
+) -> LoopFormContext:
+    """Create the 6-block LoopForm structure"""
+    ctx = LoopFormContext(
+        preheader=func.append_basic_block(f"{prefix}_lf{loop_id}_preheader"),
+        header=func.append_basic_block(f"{prefix}_lf{loop_id}_header"),
+        body=func.append_basic_block(f"{prefix}_lf{loop_id}_body"),
+        dispatch=func.append_basic_block(f"{prefix}_lf{loop_id}_dispatch"),
+        latch=func.append_basic_block(f"{prefix}_lf{loop_id}_latch"),
+        exit=func.append_basic_block(f"{prefix}_lf{loop_id}_exit"),
+        loop_id=loop_id
+    )
+    return ctx
+
+def lower_while_loopform(
+    builder: ir.IRBuilder,
+    func: ir.Function,
+    condition_vid: int,
+    body_instructions: List[Any],
+    loop_id: int,
+    vmap: Dict[int, ir.Value],
+    bb_map: Dict[int, ir.Block]
+) -> bool:
+    """
+    Lower a while loop using LoopForm structure
+    
+    Returns:
+        True if LoopForm was applied, False otherwise
+    """
+    # Check if enabled
+    if os.environ.get('NYASH_ENABLE_LOOPFORM') != '1':
+        return False
+    
+    # Create LoopForm blocks
+    lf = create_loopform_blocks(func, loop_id)
+    
+    # Preheader: Jump to header
+    builder.position_at_end(lf.preheader)
+    builder.branch(lf.header)
+    
+    # Header: Evaluate condition
+    builder.position_at_end(lf.header)
+    cond = vmap.get(condition_vid, ir.Constant(ir.IntType(1), 0))
+    # Convert to i1 if needed
+    if hasattr(cond, 'type') and cond.type == ir.IntType(64):
+        cond = builder.icmp_unsigned('!=', cond, ir.Constant(ir.IntType(64), 0))
+    builder.cbranch(cond, lf.body, lf.dispatch)
+    
+    # Body: Pass through to dispatch (Phase 1)
+    builder.position_at_end(lf.body)
+    builder.branch(lf.dispatch)
+    
+    # Dispatch: Central PHI point
+    builder.position_at_end(lf.dispatch)
+    i8 = ir.IntType(8)
+    i64 = ir.IntType(64)
+    
+    # Create PHI nodes
+    tag_phi = builder.phi(i8, name=f"lf{loop_id}_tag")
+    payload_phi = builder.phi(i64, name=f"lf{loop_id}_payload")
+    
+    # Add incoming values
+    # From header (condition false): Break signal
+    tag_phi.add_incoming(ir.Constant(i8, 1), lf.header)  # Break = 1
+    payload_phi.add_incoming(ir.Constant(i64, 0), lf.header)
+    
+    # Switch on tag
+    tag_val = tag_phi
+    switch = builder.switch(tag_val, lf.exit)
+    switch.add_case(ir.Constant(i8, 0), lf.latch)  # Next = 0
+    
+    # Latch: Back to header (if enabled)
+    builder.position_at_end(lf.latch)
+    if os.environ.get('NYASH_LOOPFORM_LATCH2HEADER') == '1':
+        builder.branch(lf.header)
+    else:
+        builder.unreachable()
+    
+    # Exit: Continue after loop
+    builder.position_at_end(lf.exit)
+    # Builder position will be set by caller
+    
+    # Store context
+    lf.tag_phi = tag_phi
+    lf.payload_phi = payload_phi
+    
+    if os.environ.get('NYASH_CLI_VERBOSE') == '1':
+        print(f"[LoopForm] Created loop structure (id={loop_id})")
+    
+    return True

src/llvm_py/instructions/ret.py

@@ -0,0 +1,49 @@
+"""
+Return instruction lowering
+Handles void and value returns
+"""
+
+import llvmlite.ir as ir
+from typing import Dict, Optional
+
+def lower_return(
+    builder: ir.IRBuilder,
+    value_id: Optional[int],
+    vmap: Dict[int, ir.Value],
+    return_type: ir.Type
+) -> None:
+    """
+    Lower MIR Return instruction
+    
+    Args:
+        builder: Current LLVM IR builder
+        value_id: Optional return value ID
+        vmap: Value map
+        return_type: Expected return type
+    """
+    if value_id is None:
+        # Void return
+        builder.ret_void()
+    else:
+        # Get return value
+        ret_val = vmap.get(value_id)
+        if not ret_val:
+            # Default based on return type
+            if isinstance(return_type, ir.IntType):
+                ret_val = ir.Constant(return_type, 0)
+            elif isinstance(return_type, ir.DoubleType):
+                ret_val = ir.Constant(return_type, 0.0)
+            else:
+                # Pointer type - null
+                ret_val = ir.Constant(return_type, None)
+        
+        # Type adjustment if needed
+        if hasattr(ret_val, 'type') and ret_val.type != return_type:
+            if isinstance(return_type, ir.IntType) and ret_val.type.is_pointer:
+                # ptr to int
+                ret_val = builder.ptrtoint(ret_val, return_type)
+            elif isinstance(return_type, ir.PointerType) and isinstance(ret_val.type, ir.IntType):
+                # int to ptr
+                ret_val = builder.inttoptr(ret_val, return_type)
+        
+        builder.ret(ret_val)

src/llvm_py/llvm_builder.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+"""
+Nyash LLVM Python Backend - Main Builder
+Following the design principles in docs/LLVM_LAYER_OVERVIEW.md
+"""
+
+import json
+import sys
+from typing import Dict, Any, Optional
+import llvmlite.ir as ir
+import llvmlite.binding as llvm
+
+class NyashLLVMBuilder:
+    """Main LLVM IR builder for Nyash MIR"""
+    
+    def __init__(self):
+        # Initialize LLVM
+        llvm.initialize()
+        llvm.initialize_native_target()
+        llvm.initialize_native_asmprinter()
+        
+        # Module and basic types
+        self.module = ir.Module(name="nyash_module")
+        self.i64 = ir.IntType(64)
+        self.i32 = ir.IntType(32)
+        self.i8 = ir.IntType(8)
+        self.i1 = ir.IntType(1)
+        self.i8p = self.i8.as_pointer()
+        self.f64 = ir.DoubleType()
+        
+    def build_from_mir(self, mir_json: Dict[str, Any]) -> str:
+        """Build LLVM IR from MIR JSON"""
+        # TODO: Implement MIR -> LLVM lowering
+        # For now, create a simple ny_main that returns 0
+        
+        # ny_main: extern "C" fn() -> i32
+        ny_main_ty = ir.FunctionType(self.i32, [])
+        ny_main = ir.Function(self.module, ny_main_ty, name="ny_main")
+        
+        block = ny_main.append_basic_block(name="entry")
+        builder = ir.IRBuilder(block)
+        builder.ret(ir.Constant(self.i32, 0))
+        
+        return str(self.module)
+    
+    def compile_to_object(self, output_path: str):
+        """Compile module to object file"""
+        # Create target machine
+        target = llvm.Target.from_default_triple()
+        target_machine = target.create_target_machine()
+        
+        # Compile
+        mod = llvm.parse_assembly(str(self.module))
+        mod.verify()
+        
+        # Generate object code
+        obj = target_machine.emit_object(mod)
+        
+        # Write to file
+        with open(output_path, 'wb') as f:
+            f.write(obj)
+
+def main():
+    if len(sys.argv) < 2:
+        print("Usage: llvm_builder.py <input.mir.json> [-o output.o]")
+        sys.exit(1)
+    
+    input_file = sys.argv[1]
+    output_file = "nyash_llvm_py.o"
+    
+    if "-o" in sys.argv:
+        idx = sys.argv.index("-o")
+        if idx + 1 < len(sys.argv):
+            output_file = sys.argv[idx + 1]
+    
+    # Read MIR JSON
+    with open(input_file, 'r') as f:
+        mir_json = json.load(f)
+    
+    # Build LLVM IR
+    builder = NyashLLVMBuilder()
+    llvm_ir = builder.build_from_mir(mir_json)
+    
+    print(f"Generated LLVM IR:\n{llvm_ir}")
+    
+    # Compile to object
+    builder.compile_to_object(output_file)
+    print(f"Compiled to {output_file}")
+
+if __name__ == "__main__":
+    main()

src/llvm_py/mir_reader.py

@@ -0,0 +1,116 @@
+"""
+MIR JSON Reader
+Parses Nyash MIR JSON format into Python structures
+"""
+
+from dataclasses import dataclass
+from typing import Dict, List, Any, Optional, Union
+from enum import Enum
+
+class MirType(Enum):
+    """MIR type enumeration"""
+    VOID = "void"
+    I64 = "i64"
+    F64 = "f64"
+    BOOL = "bool"
+    STRING = "string"
+    BOX = "box"
+    ARRAY = "array"
+    MAP = "map"
+    PTR = "ptr"
+
+@dataclass
+class MirFunction:
+    """MIR function representation"""
+    name: str
+    params: List[Tuple[str, MirType]]
+    return_type: MirType
+    blocks: Dict[int, 'MirBlock']
+    entry_block: int
+
+@dataclass
+class MirBlock:
+    """MIR basic block"""
+    id: int
+    instructions: List['MirInstruction']
+    terminator: Optional['MirInstruction']
+
+@dataclass
+class MirInstruction:
+    """Base MIR instruction"""
+    kind: str
+    
+    # Common fields
+    dst: Optional[int] = None
+    
+    # Instruction-specific fields
+    value: Optional[Any] = None  # For Const
+    op: Optional[str] = None     # For BinOp/Compare
+    lhs: Optional[int] = None    # For BinOp/Compare
+    rhs: Optional[int] = None    # For BinOp/Compare
+    cond: Optional[int] = None   # For Branch
+    then_bb: Optional[int] = None
+    else_bb: Optional[int] = None
+    target: Optional[int] = None # For Jump
+    box_val: Optional[int] = None # For BoxCall
+    method: Optional[str] = None
+    args: Optional[List[int]] = None
+    
+def parse_mir_json(data: Dict[str, Any]) -> Dict[str, MirFunction]:
+    """Parse MIR JSON into Python structures"""
+    functions = {}
+    
+    # Parse each function
+    for func_name, func_data in data.get("functions", {}).items():
+        # Parse parameters
+        params = []
+        for param in func_data.get("params", []):
+            params.append((param["name"], MirType(param["type"])))
+        
+        # Parse blocks
+        blocks = {}
+        for block_id, block_data in func_data.get("blocks", {}).items():
+            bid = int(block_id)
+            
+            # Parse instructions
+            instructions = []
+            for instr_data in block_data.get("instructions", []):
+                instr = parse_instruction(instr_data)
+                instructions.append(instr)
+            
+            # Parse terminator
+            terminator = None
+            if "terminator" in block_data:
+                terminator = parse_instruction(block_data["terminator"])
+            
+            blocks[bid] = MirBlock(bid, instructions, terminator)
+        
+        # Create function
+        func = MirFunction(
+            name=func_name,
+            params=params,
+            return_type=MirType(func_data.get("return_type", "void")),
+            blocks=blocks,
+            entry_block=func_data.get("entry_block", 0)
+        )
+        
+        functions[func_name] = func
+    
+    return functions
+
+def parse_instruction(data: Dict[str, Any]) -> MirInstruction:
+    """Parse a single MIR instruction"""
+    kind = data["kind"]
+    instr = MirInstruction(kind=kind)
+    
+    # Copy common fields
+    for field in ["dst", "value", "op", "lhs", "rhs", "cond", 
+                  "then_bb", "else_bb", "target", "box_val", "method"]:
+        if field in data:
+            setattr(instr, field, data[field])
+    
+    # Handle args array
+    if "args" in data:
+        instr.args = data["args"]
+    
+    return instr

src/llvm_py/resolver.py

@@ -0,0 +1,112 @@
+"""
+Resolver API (Python version)
+Based on src/backend/llvm/compiler/codegen/instructions/resolver.rs
+"""
+
+from typing import Dict, Optional, Any, Tuple
+import llvmlite.ir as ir
+
+class Resolver:
+    """
+    Centralized value resolution with per-block caching.
+    Following the Core Invariants from LLVM_LAYER_OVERVIEW.md:
+    - Resolver-only reads
+    - Localize at block start (PHI creation)
+    - Cache per (block, value) to avoid redundant PHIs
+    """
+    
+    def __init__(self, builder: ir.IRBuilder, module: ir.Module):
+        self.builder = builder
+        self.module = module
+        
+        # Caches: (block_name, value_id) -> llvm value
+        self.i64_cache: Dict[Tuple[str, int], ir.Value] = {}
+        self.ptr_cache: Dict[Tuple[str, int], ir.Value] = {}
+        self.f64_cache: Dict[Tuple[str, int], ir.Value] = {}
+        
+        # Type shortcuts
+        self.i64 = ir.IntType(64)
+        self.i8p = ir.IntType(8).as_pointer()
+        self.f64_type = ir.DoubleType()
+    
+    def resolve_i64(
+        self,
+        value_id: int,
+        current_block: ir.Block,
+        preds: Dict[str, list],
+        block_end_values: Dict[str, Dict[int, Any]],
+        vmap: Dict[int, Any]
+    ) -> ir.Value:
+        """
+        Resolve a MIR value as i64 dominating the current block.
+        Creates PHI at block start if needed, caches the result.
+        """
+        cache_key = (current_block.name, value_id)
+        
+        # Check cache
+        if cache_key in self.i64_cache:
+            return self.i64_cache[cache_key]
+        
+        # Get predecessor blocks
+        pred_names = preds.get(current_block.name, [])
+        
+        if not pred_names:
+            # Entry block or no predecessors
+            base_val = vmap.get(value_id, ir.Constant(self.i64, 0))
+            result = self._coerce_to_i64(base_val)
+        else:
+            # Create PHI at block start
+            saved_pos = self.builder.block
+            self.builder.position_at_start(current_block)
+            
+            phi = self.builder.phi(self.i64, name=f"loc_i64_{value_id}")
+            
+            # Add incoming values from predecessors
+            for pred_name in pred_names:
+                pred_vals = block_end_values.get(pred_name, {})
+                val = pred_vals.get(value_id, ir.Constant(self.i64, 0))
+                coerced = self._coerce_to_i64(val)
+                # Note: In real implementation, need pred block reference
+                phi.add_incoming(coerced, pred_name)  # Simplified
+            
+            # Restore position
+            if saved_pos:
+                self.builder.position_at_end(saved_pos)
+            
+            result = phi
+        
+        # Cache and return
+        self.i64_cache[cache_key] = result
+        return result
+    
+    def resolve_ptr(self, value_id: int, current_block: ir.Block, 
+                    preds: Dict, block_end_values: Dict, vmap: Dict) -> ir.Value:
+        """Resolve as i8* pointer"""
+        # Similar to resolve_i64 but with pointer type
+        # TODO: Implement
+        pass
+    
+    def resolve_f64(self, value_id: int, current_block: ir.Block,
+                    preds: Dict, block_end_values: Dict, vmap: Dict) -> ir.Value:
+        """Resolve as f64"""
+        # Similar pattern
+        # TODO: Implement
+        pass
+    
+    def _coerce_to_i64(self, val: Any) -> ir.Value:
+        """Coerce various types to i64"""
+        if isinstance(val, ir.Constant) and val.type == self.i64:
+            return val
+        elif hasattr(val, 'type') and val.type.is_pointer:
+            # ptr to int
+            return self.builder.ptrtoint(val, self.i64)
+        elif hasattr(val, 'type') and isinstance(val.type, ir.IntType):
+            # int to int (extend/trunc)
+            if val.type.width < 64:
+                return self.builder.zext(val, self.i64)
+            elif val.type.width > 64:
+                return self.builder.trunc(val, self.i64)
+            return val
+        else:
+            # Default zero
+            return ir.Constant(self.i64, 0)

src/llvm_py/test_simple.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+"""
+Simple test for Nyash LLVM Python backend
+Tests basic MIR -> LLVM compilation
+"""
+
+import json
+from llvm_builder import NyashLLVMBuilder
+
+# Simple MIR test case: function that returns 42
+test_mir = {
+    "functions": {
+        "main": {
+            "name": "main",
+            "params": [],
+            "return_type": "i64",
+            "entry_block": 0,
+            "blocks": {
+                "0": {
+                    "instructions": [
+                        {
+                            "kind": "Const",
+                            "dst": 0,
+                            "value": {"type": "i64", "value": 42}
+                        }
+                    ],
+                    "terminator": {
+                        "kind": "Return",
+                        "value": 0
+                    }
+                }
+            }
+        }
+    }
+}
+
+def test_basic():
+    """Test basic MIR -> LLVM compilation"""
+    builder = NyashLLVMBuilder()
+    
+    # Generate LLVM IR
+    llvm_ir = builder.build_from_mir(test_mir)
+    print("Generated LLVM IR:")
+    print(llvm_ir)
+    
+    # Compile to object file
+    builder.compile_to_object("test_simple.o")
+    print("\nCompiled to test_simple.o")
+
+if __name__ == "__main__":
+    test_basic()