feat(llvm-py): Major breakthrough in Python LLVM backend! 🎉

✅ Print and FileBox paths now working correctly
✅ Resolver simplified by removing overly aggressive fast-path optimization
✅ Both OFF/ON in compare_harness_on_off.sh now use Python version
✅ String handle propagation issues resolved

Key changes:
- Removed instruction reordering in llvm_builder.py (respecting MIR order)
- Resolver now more conservative but reliable
- compare_harness_on_off.sh updated to use Python backend for both paths

This marks a major milestone towards Phase 15 self-hosting with Python/llvmlite!

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/backend/llvm_legacy/README.md

@@ -0,0 +1,8 @@
+# Legacy Rust/inkwell LLVM backend
+
+This directory holds the historical LLVM backend implemented in Rust with inkwell.
+
+- Status: DEPRECATED — kept for reference.
+- Current primary LLVM path is Python/llvmlite under `src/llvm_py/`.
+- Cargo feature to enable this backend: `llvm-inkwell-legacy`.
+

src/backend/llvm_legacy/box_types.rs

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+// legacy box type id helpers placeholder; refer to archived implementation if needed
+
+pub fn load_box_type_ids() -> std::collections::HashMap<String, u32> {
+    std::collections::HashMap::new()
+}
+

src/backend/llvm_legacy/compiler/aot.rs

@@ -0,0 +1,2 @@
+// legacy aot placeholder; full implementation retained in archived branch or prior history
+

src/backend/llvm_legacy/compiler/helpers.rs

@@ -0,0 +1,2 @@
+// legacy helpers placeholder; kept to satisfy module structure after move
+

src/backend/llvm_legacy/compiler/mock.rs

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+use crate::mir::function::MirModule;
+use crate::box_trait::{NyashBox, IntegerBox};
+use std::collections::HashMap;
+
+pub struct LLVMCompiler {
+    values: HashMap<crate::mir::ValueId, Box<dyn NyashBox>>,
+}
+
+impl LLVMCompiler {
+    pub fn new() -> Result<Self, String> {
+        Ok(Self { values: HashMap::new() })
+    }
+
+    pub fn compile_module(&self, _mir: &MirModule, _out: &str) -> Result<(), String> {
+        // Mock: pretend emitted
+        Ok(())
+    }
+
+    pub fn compile_and_execute(&mut self, _mir: &MirModule, _out: &str) -> Result<Box<dyn NyashBox>, String> {
+        Ok(Box::new(IntegerBox::new(0)))
+    }
+}
+

src/backend/llvm_legacy/compiler/mod.rs

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+use crate::box_trait::NyashBox;
+use crate::mir::ValueId;
+use std::collections::HashMap;
+
+pub struct LLVMCompiler {
+    values: HashMap<ValueId, Box<dyn NyashBox>>,
+}
+
+#[cfg(not(feature = "llvm-inkwell-legacy"))]
+mod mock;
+#[cfg(not(feature = "llvm-inkwell-legacy"))]
+pub use mock::*;
+
+#[cfg(feature = "llvm-inkwell-legacy")]
+mod aot;
+#[cfg(feature = "llvm-inkwell-legacy")]
+mod codegen;
+#[cfg(feature = "llvm-inkwell-legacy")]
+mod helpers;
+#[cfg(feature = "llvm-inkwell-legacy")]
+mod interpreter;
+#[cfg(feature = "llvm-inkwell-legacy")]
+pub use aot::*;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_llvm_module_creation() {
+        assert!(true);
+    }
+}
+

src/backend/llvm_legacy/context.rs

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+/*!
+ * LLVM Context Management - Handle LLVM context, module, and target setup (legacy)
+ */
+
+/// Mock implementation when legacy inkwell backend is disabled
+#[cfg(not(feature = "llvm-inkwell-legacy"))]
+pub struct CodegenContext {
+    _phantom: std::marker::PhantomData<()>,
+}
+
+#[cfg(not(feature = "llvm-inkwell-legacy"))]
+impl CodegenContext {
+    pub fn new(_module_name: &str) -> Result<Self, String> {
+        Ok(Self { _phantom: std::marker::PhantomData })
+    }
+}
+
+// Real implementation (compiled only when feature "llvm-inkwell-legacy" is enabled)
+#[cfg(feature = "llvm-inkwell-legacy")]
+use inkwell::context::Context;
+#[cfg(feature = "llvm-inkwell-legacy")]
+use inkwell::module::Module;
+#[cfg(feature = "llvm-inkwell-legacy")]
+use inkwell::builder::Builder;
+#[cfg(feature = "llvm-inkwell-legacy")]
+use inkwell::targets::{Target, TargetMachine, InitializationConfig};
+
+#[cfg(feature = "llvm-inkwell-legacy")]
+pub struct CodegenContext<'ctx> {
+    pub context: &'ctx Context,
+    pub module: Module<'ctx>,
+    pub builder: Builder<'ctx>,
+    pub target_machine: TargetMachine,
+}
+
+#[cfg(feature = "llvm-inkwell-legacy")]
+impl<'ctx> CodegenContext<'ctx> {
+    pub fn new(context: &'ctx Context, module_name: &str) -> Result<Self, String> {
+        Target::initialize_native(&InitializationConfig::default())
+            .map_err(|e| format!("Failed to initialize native target: {}", e))?;
+        let module = context.create_module(module_name);
+        let triple = TargetMachine::get_default_triple();
+        let target = Target::from_triple(&triple)
+            .map_err(|e| format!("Failed to get target: {}", e))?;
+        let target_machine = target
+            .create_target_machine(
+                &triple,
+                "generic",
+                "",
+                inkwell::OptimizationLevel::None,
+                inkwell::targets::RelocMode::Default,
+                inkwell::targets::CodeModel::Default,
+            )
+            .ok_or_else(|| "Failed to create target machine".to_string())?;
+        let builder = context.create_builder();
+        Ok(Self { context, module, builder, target_machine })
+    }
+}
+

src/backend/llvm_legacy/mod.rs

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+/*!
+ * LLVM Backend Module (legacy, inkwell) - Compile MIR to LLVM IR for AOT execution
+ *
+ * This module provides LLVM-based compilation of Nyash MIR to native code.
+ * Phase 9.78 PoC implementation focused on minimal support.
+ */
+
+pub mod box_types;
+pub mod compiler;
+pub mod context;
+
+use crate::box_trait::NyashBox;
+use crate::mir::function::MirModule;
+
+/// Compile MIR module to object file and execute
+pub fn compile_and_execute(
+    mir_module: &MirModule,
+    output_path: &str,
+) -> Result<Box<dyn NyashBox>, String> {
+    let mut compiler = compiler::LLVMCompiler::new()?;
+    compiler.compile_and_execute(mir_module, output_path)
+}
+
+/// Compile MIR module to object file only
+pub fn compile_to_object(mir_module: &MirModule, output_path: &str) -> Result<(), String> {
+    let compiler = compiler::LLVMCompiler::new()?;
+    compiler.compile_module(mir_module, output_path)
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_llvm_module_creation() {
+        assert!(true);
+    }
+}
+