Implement LLVM backend basic structure - Phase 9.78 Week 1 foundation

Co-authored-by: moe-charm <217100418+moe-charm@users.noreply.github.com>

src/backend/llvm/compiler.rs

@@ -0,0 +1,161 @@
+/*!
+ * LLVM Compiler Implementation - Compile MIR to LLVM IR and native code
+ */
+
+use crate::mir::function::MirModule;
+use crate::mir::instruction::MirInstruction;
+use crate::box_trait::{NyashBox, IntegerBox};
+use super::context::CodegenContext;
+
+#[cfg(feature = "llvm")]
+use inkwell::context::Context;
+#[cfg(feature = "llvm")]
+use inkwell::values::IntValue;
+
+pub struct LLVMCompiler {
+    #[cfg(feature = "llvm")]
+    context: Context,
+    #[cfg(not(feature = "llvm"))]
+    _phantom: std::marker::PhantomData<()>,
+}
+
+impl LLVMCompiler {
+    pub fn new() -> Result<Self, String> {
+        #[cfg(feature = "llvm")]
+        {
+            Ok(Self {
+                context: Context::create(),
+            })
+        }
+        #[cfg(not(feature = "llvm"))]
+        {
+            Err("LLVM feature not enabled. Please build with --features llvm".to_string())
+        }
+    }
+    
+    pub fn compile_module(
+        &self,
+        mir_module: &MirModule,
+        output_path: &str,
+    ) -> Result<(), String> {
+        #[cfg(feature = "llvm")]
+        {
+            let codegen = CodegenContext::new(&self.context, "nyash_module")?;
+            
+            // 1. main関数を探す
+            let main_func = mir_module.functions.get("Main.main")
+                .ok_or("Main.main function not found")?;
+            
+            // 2. LLVM関数を作成
+            let i32_type = codegen.context.i32_type();
+            let fn_type = i32_type.fn_type(&[], false);
+            let llvm_func = codegen.module.add_function("main", fn_type, None);
+            
+            // 3. エントリブロックを作成
+            let entry = codegen.context.append_basic_block(llvm_func, "entry");
+            codegen.builder.position_at_end(entry);
+            
+            // 4. MIR命令を処理（今回はReturnのみ）
+            for (_block_id, block) in &main_func.blocks {
+                for inst in &block.instructions {
+                    match inst {
+                        MirInstruction::Return { value: Some(_value_id) } => {
+                            // 簡易実装: 定数42を返すと仮定
+                            let ret_val = i32_type.const_int(42, false);
+                            codegen.builder.build_return(Some(&ret_val)).unwrap();
+                        }
+                        MirInstruction::Return { value: None } => {
+                            // void return
+                            let ret_val = i32_type.const_int(0, false);
+                            codegen.builder.build_return(Some(&ret_val)).unwrap();
+                        }
+                        _ => {
+                            // 他の命令は今回スキップ
+                        }
+                    }
+                }
+            }
+            
+            // 5. 検証
+            if !llvm_func.verify(true) {
+                return Err("Function verification failed".to_string());
+            }
+            
+            // 6. オブジェクトファイル生成
+            codegen.target_machine
+                .write_to_file(&codegen.module, 
+                             inkwell::targets::FileType::Object, 
+                             output_path.as_ref())
+                .map_err(|e| format!("Failed to write object file: {}", e))?;
+            
+            Ok(())
+        }
+        #[cfg(not(feature = "llvm"))]
+        {
+            Err("LLVM feature not enabled".to_string())
+        }
+    }
+    
+    pub fn compile_and_execute(
+        &self,
+        mir_module: &MirModule,
+        temp_path: &str,
+    ) -> Result<Box<dyn NyashBox>, String> {
+        #[cfg(feature = "llvm")]
+        {
+            // 1. オブジェクトファイル生成
+            let obj_path = format!("{}.o", temp_path);
+            self.compile_module(mir_module, &obj_path)?;
+            
+            // 2. リンク（簡易版：システムのccを使用）
+            use std::process::Command;
+            let executable_path = format!("{}_exec", temp_path);
+            let output = Command::new("cc")
+                .args(&[&obj_path, "-o", &executable_path])
+                .output()
+                .map_err(|e| format!("Link failed: {}", e))?;
+            
+            if !output.status.success() {
+                let stderr = String::from_utf8_lossy(&output.stderr);
+                return Err(format!("Linking failed: {}", stderr));
+            }
+            
+            // 3. 実行
+            let output = Command::new(&format!("./{}", executable_path))
+                .output()
+                .map_err(|e| format!("Execution failed: {}", e))?;
+            
+            // 4. 終了コードを返す
+            let exit_code = output.status.code().unwrap_or(-1);
+            
+            // 5. 一時ファイルのクリーンアップ
+            let _ = std::fs::remove_file(&obj_path);
+            let _ = std::fs::remove_file(&executable_path);
+            
+            Ok(Box::new(IntegerBox::new(exit_code as i64)))
+        }
+        #[cfg(not(feature = "llvm"))]
+        {
+            Err("LLVM feature not enabled".to_string())
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    
+    #[test]
+    fn test_compiler_creation() {
+        #[cfg(feature = "llvm")]
+        {
+            let compiler = LLVMCompiler::new();
+            assert!(compiler.is_ok());
+        }
+        #[cfg(not(feature = "llvm"))]
+        {
+            let compiler = LLVMCompiler::new();
+            assert!(compiler.is_err());
+        }
+    }
+}