add prelude.bc and code in llvm_interpreter to load the prelude from the bitcode

Author: bollu

prelude.bc

@@ -14,6 +14,8 @@ use llvm_sys::prelude::*;
 use llvm_sys::analysis::*;
 use llvm_sys::target::*;
 use llvm_sys::target_machine::*;
+use std::os::raw::c_char;
+use llvm_sys::bit_reader::*;
 use llvm_sys::execution_engine::*;
 
 use std::os::raw::{c_ulonglong, c_uint};
@@ -26,6 +28,12 @@ use value::{Value, Number};
 use libc;
 
 
+fn char_ptr_to_string(char_ptr: *const c_char) -> String {
+    unsafe {
+        CStr::from_ptr(char_ptr as *const _).to_str().expect("expected correct char* to str").to_owned()
+    }
+}
+
 const LLVM_FALSE: LLVMBool = 0;
 const LLVM_TRUE: LLVMBool = 1;
 
@@ -960,10 +968,32 @@ fn create_module(module_name: &str, target_triple: Option<String>) -> Module {
     module
 }
 
+
+fn load_llvm_prelude_from_file(path: &str) -> Module {
+    unsafe  {
+        let mut out : LLVMModuleRef = mem::uninitialized();
+
+        let mut out_message_raw : *mut c_char = mem::uninitialized();
+        let path_cstr : CString = CString::new(path).unwrap();
+        let mut membuf : LLVMMemoryBufferRef = mem::uninitialized();
+        if 0 != LLVMCreateMemoryBufferWithContentsOfFile(path_cstr.as_ptr(), &mut membuf, &mut out_message_raw) {
+            panic!("unable to read memory buffer from file: {}", char_ptr_to_string(out_message_raw))
+        }
+
+
+        if 0 != LLVMParseBitcode2(membuf, &mut out) {
+            panic!("unable to load module")
+        }
+        Module {module: out, strings: Vec::new()}
+            
+    }
+}
+
 fn interpret_statements(stmts: &[StmtNode],
                         _: Rc<RefCell<Environment>>)
                         -> Result<Option<StmtResult>, RuntimeErrorWithPosition> {
     let target_triple: Option<String> = None;
+    /*
     let mut module = create_module("ModuleName", target_triple);
 
     let c_declarations = gen_c_declarations(&mut module);
@@ -974,6 +1004,11 @@ fn interpret_statements(stmts: &[StmtNode],
 
     print!("@@@@@@Module after all prelude generation:\n{:?}\n----",
            module);
+    */
+
+    let other_module = load_llvm_prelude_from_file("prelude.bc");
+    println!("####@@@###@@@####@@@###\nother module: {:?}", other_module);
+    /*
 
     unsafe {
 
@@ -1025,6 +1060,7 @@ fn interpret_statements(stmts: &[StmtNode],
         jit.add_module(module, main_fn, c_declarations);
 
     };
+    */