diff options
Diffstat (limited to 'compiler/rustc_codegen_cranelift/src/driver/jit.rs')
| -rw-r--r-- | compiler/rustc_codegen_cranelift/src/driver/jit.rs | 225 |
1 files changed, 20 insertions, 205 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/driver/jit.rs b/compiler/rustc_codegen_cranelift/src/driver/jit.rs index 57c88f4b0f9..41f8bb9161c 100644 --- a/compiler/rustc_codegen_cranelift/src/driver/jit.rs +++ b/compiler/rustc_codegen_cranelift/src/driver/jit.rs @@ -1,75 +1,27 @@ //! The JIT driver uses [`cranelift_jit`] to JIT execute programs without writing any object //! files. -use std::cell::RefCell; use std::ffi::CString; use std::os::raw::{c_char, c_int}; -use std::sync::{Mutex, OnceLock, mpsc}; -use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext}; use cranelift_jit::{JITBuilder, JITModule}; use rustc_codegen_ssa::CrateInfo; use rustc_middle::mir::mono::MonoItem; use rustc_session::Session; use rustc_span::sym; +use crate::CodegenCx; use crate::debuginfo::TypeDebugContext; use crate::prelude::*; use crate::unwind_module::UnwindModule; -use crate::{CodegenCx, CodegenMode}; -struct JitState { - jit_module: UnwindModule<JITModule>, -} - -thread_local! { - static LAZY_JIT_STATE: RefCell<Option<JitState>> = const { RefCell::new(None) }; -} - -/// The Sender owned by the rustc thread -static GLOBAL_MESSAGE_SENDER: OnceLock<Mutex<mpsc::Sender<UnsafeMessage>>> = OnceLock::new(); - -/// A message that is sent from the jitted runtime to the rustc thread. -/// Senders are responsible for upholding `Send` semantics. -enum UnsafeMessage { - /// Request that the specified `Instance` be lazily jitted. - /// - /// Nothing accessible through `instance_ptr` may be moved or mutated by the sender after - /// this message is sent. - JitFn { - instance_ptr: *const Instance<'static>, - trampoline_ptr: *const u8, - tx: mpsc::Sender<*const u8>, - }, -} -unsafe impl Send for UnsafeMessage {} - -impl UnsafeMessage { - /// Send the message. - fn send(self) { - thread_local! { - /// The Sender owned by the local thread - static LOCAL_MESSAGE_SENDER: mpsc::Sender<UnsafeMessage> = - GLOBAL_MESSAGE_SENDER - .get().unwrap() - .lock().unwrap() - .clone(); - } - LOCAL_MESSAGE_SENDER.with(|sender| { - sender.send(self).expect("rustc thread hung up before lazy JIT request was sent") - }) - } -} - -fn create_jit_module(tcx: TyCtxt<'_>, hotswap: bool) -> (UnwindModule<JITModule>, CodegenCx) { +fn create_jit_module(tcx: TyCtxt<'_>) -> (UnwindModule<JITModule>, CodegenCx) { let crate_info = CrateInfo::new(tcx, "dummy_target_cpu".to_string()); - let isa = crate::build_isa(tcx.sess); + let isa = crate::build_isa(tcx.sess, true); let mut jit_builder = JITBuilder::with_isa(isa, cranelift_module::default_libcall_names()); - jit_builder.hotswap(hotswap); crate::compiler_builtins::register_functions_for_jit(&mut jit_builder); jit_builder.symbol_lookup_fn(dep_symbol_lookup_fn(tcx.sess, crate_info)); - jit_builder.symbol("__clif_jit_fn", clif_jit_fn as *const u8); let mut jit_module = UnwindModule::new(JITModule::new(jit_builder), false); let cx = crate::CodegenCx::new(tcx, jit_module.isa(), false, sym::dummy_cgu_name); @@ -79,7 +31,7 @@ fn create_jit_module(tcx: TyCtxt<'_>, hotswap: bool) -> (UnwindModule<JITModule> (jit_module, cx) } -pub(crate) fn run_jit(tcx: TyCtxt<'_>, codegen_mode: CodegenMode, jit_args: Vec<String>) -> ! { +pub(crate) fn run_jit(tcx: TyCtxt<'_>, jit_args: Vec<String>) -> ! { if !tcx.sess.opts.output_types.should_codegen() { tcx.dcx().fatal("JIT mode doesn't work with `cargo check`"); } @@ -88,8 +40,7 @@ pub(crate) fn run_jit(tcx: TyCtxt<'_>, codegen_mode: CodegenMode, jit_args: Vec< tcx.dcx().fatal("can't jit non-executable crate"); } - let (mut jit_module, mut cx) = - create_jit_module(tcx, matches!(codegen_mode, CodegenMode::JitLazy)); + let (mut jit_module, mut cx) = create_jit_module(tcx); let mut cached_context = Context::new(); let cgus = tcx.collect_and_partition_mono_items(()).codegen_units; @@ -105,21 +56,15 @@ pub(crate) fn run_jit(tcx: TyCtxt<'_>, codegen_mode: CodegenMode, jit_args: Vec< super::predefine_mono_items(tcx, &mut jit_module, &mono_items); for (mono_item, _) in mono_items { match mono_item { - MonoItem::Fn(inst) => match codegen_mode { - CodegenMode::Aot => unreachable!(), - CodegenMode::Jit => { - codegen_and_compile_fn( - tcx, - &mut cx, - &mut cached_context, - &mut jit_module, - inst, - ); - } - CodegenMode::JitLazy => { - codegen_shim(tcx, &mut cached_context, &mut jit_module, inst) - } - }, + MonoItem::Fn(inst) => { + codegen_and_compile_fn( + tcx, + &mut cx, + &mut cached_context, + &mut jit_module, + inst, + ); + } MonoItem::Static(def_id) => { crate::constant::codegen_static(tcx, &mut jit_module, def_id); } @@ -161,41 +106,17 @@ pub(crate) fn run_jit(tcx: TyCtxt<'_>, codegen_mode: CodegenMode, jit_args: Vec< let start_func_id = jit_module.declare_function("main", Linkage::Import, &start_sig).unwrap(); let finalized_start: *const u8 = jit_module.module.get_finalized_function(start_func_id); - LAZY_JIT_STATE.with(|lazy_jit_state| { - let mut lazy_jit_state = lazy_jit_state.borrow_mut(); - assert!(lazy_jit_state.is_none()); - *lazy_jit_state = Some(JitState { jit_module }); - }); - let f: extern "C" fn(c_int, *const *const c_char) -> c_int = unsafe { ::std::mem::transmute(finalized_start) }; - let (tx, rx) = mpsc::channel(); - GLOBAL_MESSAGE_SENDER.set(Mutex::new(tx)).unwrap(); - - // Spawn the jitted runtime in a new thread so that this rustc thread can handle messages - // (eg to lazily JIT further functions as required) - std::thread::spawn(move || { - let mut argv = args.iter().map(|arg| arg.as_ptr()).collect::<Vec<_>>(); + let mut argv = args.iter().map(|arg| arg.as_ptr()).collect::<Vec<_>>(); - // Push a null pointer as a terminating argument. This is required by POSIX and - // useful as some dynamic linkers use it as a marker to jump over. - argv.push(std::ptr::null()); + // Push a null pointer as a terminating argument. This is required by POSIX and + // useful as some dynamic linkers use it as a marker to jump over. + argv.push(std::ptr::null()); - let ret = f(args.len() as c_int, argv.as_ptr()); - std::process::exit(ret); - }); - - // Handle messages - loop { - match rx.recv().unwrap() { - // lazy JIT compilation request - compile requested instance and return pointer to result - UnsafeMessage::JitFn { instance_ptr, trampoline_ptr, tx } => { - tx.send(jit_fn(instance_ptr, trampoline_ptr)) - .expect("jitted runtime hung up before response to lazy JIT request was sent"); - } - } - } + let ret = f(args.len() as c_int, argv.as_ptr()); + std::process::exit(ret); } pub(crate) fn codegen_and_compile_fn<'tcx>( @@ -227,58 +148,6 @@ pub(crate) fn codegen_and_compile_fn<'tcx>( }); } -extern "C" fn clif_jit_fn( - instance_ptr: *const Instance<'static>, - trampoline_ptr: *const u8, -) -> *const u8 { - // send the JIT request to the rustc thread, with a channel for the response - let (tx, rx) = mpsc::channel(); - UnsafeMessage::JitFn { instance_ptr, trampoline_ptr, tx }.send(); - - // block on JIT compilation result - rx.recv().expect("rustc thread hung up before responding to sent lazy JIT request") -} - -fn jit_fn(instance_ptr: *const Instance<'static>, trampoline_ptr: *const u8) -> *const u8 { - rustc_middle::ty::tls::with(|tcx| { - // lift is used to ensure the correct lifetime for instance. - let instance = tcx.lift(unsafe { *instance_ptr }).unwrap(); - - LAZY_JIT_STATE.with(|lazy_jit_state| { - let mut lazy_jit_state = lazy_jit_state.borrow_mut(); - let lazy_jit_state = lazy_jit_state.as_mut().unwrap(); - let jit_module = &mut lazy_jit_state.jit_module; - - let name = tcx.symbol_name(instance).name; - let sig = crate::abi::get_function_sig( - tcx, - jit_module.target_config().default_call_conv, - instance, - ); - let func_id = jit_module.declare_function(name, Linkage::Export, &sig).unwrap(); - - let current_ptr = jit_module.module.read_got_entry(func_id); - - // If the function's GOT entry has already been updated to point at something other - // than the shim trampoline, don't re-jit but just return the new pointer instead. - // This does not need synchronization as this code is executed only by a sole rustc - // thread. - if current_ptr != trampoline_ptr { - return current_ptr; - } - - jit_module.module.prepare_for_function_redefine(func_id).unwrap(); - - let mut cx = crate::CodegenCx::new(tcx, jit_module.isa(), false, sym::dummy_cgu_name); - codegen_and_compile_fn(tcx, &mut cx, &mut Context::new(), jit_module, instance); - - assert!(cx.global_asm.is_empty()); - jit_module.finalize_definitions(); - jit_module.module.get_finalized_function(func_id) - }) - }) -} - fn dep_symbol_lookup_fn( sess: &Session, crate_info: CrateInfo, @@ -326,57 +195,3 @@ fn dep_symbol_lookup_fn( None }) } - -fn codegen_shim<'tcx>( - tcx: TyCtxt<'tcx>, - cached_context: &mut Context, - module: &mut UnwindModule<JITModule>, - inst: Instance<'tcx>, -) { - let pointer_type = module.target_config().pointer_type(); - - let name = tcx.symbol_name(inst).name; - let sig = crate::abi::get_function_sig(tcx, module.target_config().default_call_conv, inst); - let func_id = module.declare_function(name, Linkage::Export, &sig).unwrap(); - - let instance_ptr = Box::into_raw(Box::new(inst)); - - let jit_fn = module - .declare_function( - "__clif_jit_fn", - Linkage::Import, - &Signature { - call_conv: module.target_config().default_call_conv, - params: vec![AbiParam::new(pointer_type), AbiParam::new(pointer_type)], - returns: vec![AbiParam::new(pointer_type)], - }, - ) - .unwrap(); - - let context = cached_context; - context.clear(); - let trampoline = &mut context.func; - trampoline.signature = sig.clone(); - - let mut builder_ctx = FunctionBuilderContext::new(); - let mut trampoline_builder = FunctionBuilder::new(trampoline, &mut builder_ctx); - - let trampoline_fn = module.declare_func_in_func(func_id, trampoline_builder.func); - let jit_fn = module.declare_func_in_func(jit_fn, trampoline_builder.func); - let sig_ref = trampoline_builder.func.import_signature(sig); - - let entry_block = trampoline_builder.create_block(); - trampoline_builder.append_block_params_for_function_params(entry_block); - let fn_args = trampoline_builder.func.dfg.block_params(entry_block).to_vec(); - - trampoline_builder.switch_to_block(entry_block); - let instance_ptr = trampoline_builder.ins().iconst(pointer_type, instance_ptr as u64 as i64); - let trampoline_ptr = trampoline_builder.ins().func_addr(pointer_type, trampoline_fn); - let jitted_fn = trampoline_builder.ins().call(jit_fn, &[instance_ptr, trampoline_ptr]); - let jitted_fn = trampoline_builder.func.dfg.inst_results(jitted_fn)[0]; - let call_inst = trampoline_builder.ins().call_indirect(sig_ref, jitted_fn, &fn_args); - let ret_vals = trampoline_builder.func.dfg.inst_results(call_inst).to_vec(); - trampoline_builder.ins().return_(&ret_vals); - - module.define_function(func_id, context).unwrap(); -} |