use rustc::middle::lang_items; use rustc::ty::{self, Ty, TypeFoldable}; use rustc::ty::layout::{self, LayoutOf, HasTyCtxt}; use rustc::mir::{self, Place, PlaceBase, Static, StaticKind}; use rustc::mir::interpret::InterpError; use rustc_target::abi::call::{ArgType, FnType, PassMode, IgnoreMode}; use rustc_target::spec::abi::Abi; use rustc_mir::monomorphize; use crate::base; use crate::MemFlags; use crate::common::{self, IntPredicate}; use crate::meth; use crate::traits::*; use std::borrow::Cow; use syntax::symbol::Symbol; use syntax_pos::Pos; use super::{FunctionCx, LocalRef}; use super::place::PlaceRef; use super::operand::OperandRef; use super::operand::OperandValue::{Pair, Ref, Immediate}; /// Used by `FunctionCx::codegen_terminator` for emitting common patterns /// e.g., creating a basic block, calling a function, etc. struct TerminatorCodegenHelper<'a, 'tcx> { bb: &'a mir::BasicBlock, terminator: &'a mir::Terminator<'tcx>, funclet_bb: Option, } impl<'a, 'tcx> TerminatorCodegenHelper<'a, 'tcx> { /// Returns the associated funclet from `FunctionCx::funclets` for the /// `funclet_bb` member if it is not `None`. fn funclet<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>( &self, fx: &'c mut FunctionCx<'b, 'tcx, Bx>, ) -> Option<&'c Bx::Funclet> { match self.funclet_bb { Some(funcl) => fx.funclets[funcl].as_ref(), None => None, } } fn lltarget<'b, 'c, Bx: BuilderMethods<'b, 'tcx>>( &self, fx: &'c mut FunctionCx<'b, 'tcx, Bx>, target: mir::BasicBlock, ) -> (Bx::BasicBlock, bool) { let span = self.terminator.source_info.span; let lltarget = fx.blocks[target]; let target_funclet = fx.cleanup_kinds[target].funclet_bb(target); match (self.funclet_bb, target_funclet) { (None, None) => (lltarget, false), (Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) => (lltarget, false), // jump *into* cleanup - need a landing pad if GNU (None, Some(_)) => (fx.landing_pad_to(target), false), (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator), (Some(_), Some(_)) => (fx.landing_pad_to(target), true), } } /// Create a basic block. fn llblock<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>( &self, fx: &'c mut FunctionCx<'b, 'tcx, Bx>, target: mir::BasicBlock, ) -> Bx::BasicBlock { let (lltarget, is_cleanupret) = self.lltarget(fx, target); if is_cleanupret { // MSVC cross-funclet jump - need a trampoline debug!("llblock: creating cleanup trampoline for {:?}", target); let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target); let mut trampoline = fx.new_block(name); trampoline.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget)); trampoline.llbb() } else { lltarget } } fn funclet_br<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>( &self, fx: &'c mut FunctionCx<'b, 'tcx, Bx>, bx: &mut Bx, target: mir::BasicBlock, ) { let (lltarget, is_cleanupret) = self.lltarget(fx, target); if is_cleanupret { // micro-optimization: generate a `ret` rather than a jump // to a trampoline. bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget)); } else { bx.br(lltarget); } } /// Call `fn_ptr` of `fn_ty` with the arguments `llargs`, the optional /// return destination `destination` and the cleanup function `cleanup`. fn do_call<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>( &self, fx: &'c mut FunctionCx<'b, 'tcx, Bx>, bx: &mut Bx, fn_ty: FnType<'tcx, Ty<'tcx>>, fn_ptr: Bx::Value, llargs: &[Bx::Value], destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>, cleanup: Option, ) { if let Some(cleanup) = cleanup { let ret_bx = if let Some((_, target)) = destination { fx.blocks[target] } else { fx.unreachable_block() }; let invokeret = bx.invoke(fn_ptr, &llargs, ret_bx, self.llblock(fx, cleanup), self.funclet(fx)); bx.apply_attrs_callsite(&fn_ty, invokeret); if let Some((ret_dest, target)) = destination { let mut ret_bx = fx.build_block(target); fx.set_debug_loc(&mut ret_bx, self.terminator.source_info); fx.store_return(&mut ret_bx, ret_dest, &fn_ty.ret, invokeret); } } else { let llret = bx.call(fn_ptr, &llargs, self.funclet(fx)); bx.apply_attrs_callsite(&fn_ty, llret); if fx.mir[*self.bb].is_cleanup { // Cleanup is always the cold path. Don't inline // drop glue. Also, when there is a deeply-nested // struct, there are "symmetry" issues that cause // exponential inlining - see issue #41696. bx.do_not_inline(llret); } if let Some((ret_dest, target)) = destination { fx.store_return(bx, ret_dest, &fn_ty.ret, llret); self.funclet_br(fx, bx, target); } else { bx.unreachable(); } } } } /// Codegen implementations for some terminator variants. impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { /// Generates code for a `Resume` terminator. fn codegen_resume_terminator<'b>( &mut self, helper: TerminatorCodegenHelper<'b, 'tcx>, mut bx: Bx, ) { if let Some(funclet) = helper.funclet(self) { bx.cleanup_ret(funclet, None); } else { let slot = self.get_personality_slot(&mut bx); let lp0 = slot.project_field(&mut bx, 0); let lp0 = bx.load_operand(lp0).immediate(); let lp1 = slot.project_field(&mut bx, 1); let lp1 = bx.load_operand(lp1).immediate(); slot.storage_dead(&mut bx); if !bx.sess().target.target.options.custom_unwind_resume { let mut lp = bx.const_undef(self.landing_pad_type()); lp = bx.insert_value(lp, lp0, 0); lp = bx.insert_value(lp, lp1, 1); bx.resume(lp); } else { bx.call(bx.eh_unwind_resume(), &[lp0], helper.funclet(self)); bx.unreachable(); } } } fn codegen_switchint_terminator<'b>( &mut self, helper: TerminatorCodegenHelper<'b, 'tcx>, mut bx: Bx, discr: &mir::Operand<'tcx>, switch_ty: Ty<'tcx>, values: &Cow<'tcx, [u128]>, targets: &Vec, ) { let discr = self.codegen_operand(&mut bx, &discr); if targets.len() == 2 { // If there are two targets, emit br instead of switch let lltrue = helper.llblock(self, targets[0]); let llfalse = helper.llblock(self, targets[1]); if switch_ty == bx.tcx().types.bool { // Don't generate trivial icmps when switching on bool if let [0] = values[..] { bx.cond_br(discr.immediate(), llfalse, lltrue); } else { assert_eq!(&values[..], &[1]); bx.cond_br(discr.immediate(), lltrue, llfalse); } } else { let switch_llty = bx.immediate_backend_type( bx.layout_of(switch_ty) ); let llval = bx.const_uint_big(switch_llty, values[0]); let cmp = bx.icmp(IntPredicate::IntEQ, discr.immediate(), llval); bx.cond_br(cmp, lltrue, llfalse); } } else { let (otherwise, targets) = targets.split_last().unwrap(); bx.switch( discr.immediate(), helper.llblock(self, *otherwise), values.iter().zip(targets).map(|(&value, target)| { (value, helper.llblock(self, *target)) }) ); } } fn codegen_return_terminator<'b>( &mut self, mut bx: Bx, ) { if self.fn_ty.c_variadic { match self.va_list_ref { Some(va_list) => { bx.va_end(va_list.llval); } None => { bug!("C-variadic function must have a `va_list_ref`"); } } } if self.fn_ty.ret.layout.abi.is_uninhabited() { // Functions with uninhabited return values are marked `noreturn`, // so we should make sure that we never actually do. bx.abort(); bx.unreachable(); return; } let llval = match self.fn_ty.ret.mode { PassMode::Ignore(IgnoreMode::Zst) | PassMode::Indirect(..) => { bx.ret_void(); return; } PassMode::Ignore(IgnoreMode::CVarArgs) => { bug!("C-variadic arguments should never be the return type"); } PassMode::Direct(_) | PassMode::Pair(..) => { let op = self.codegen_consume(&mut bx, &mir::Place::RETURN_PLACE); if let Ref(llval, _, align) = op.val { bx.load(llval, align) } else { op.immediate_or_packed_pair(&mut bx) } } PassMode::Cast(cast_ty) => { let op = match self.locals[mir::RETURN_PLACE] { LocalRef::Operand(Some(op)) => op, LocalRef::Operand(None) => bug!("use of return before def"), LocalRef::Place(cg_place) => { OperandRef { val: Ref(cg_place.llval, None, cg_place.align), layout: cg_place.layout } } LocalRef::UnsizedPlace(_) => bug!("return type must be sized"), }; let llslot = match op.val { Immediate(_) | Pair(..) => { let scratch = PlaceRef::alloca(&mut bx, self.fn_ty.ret.layout, "ret"); op.val.store(&mut bx, scratch); scratch.llval } Ref(llval, _, align) => { assert_eq!(align, op.layout.align.abi, "return place is unaligned!"); llval } }; let addr = bx.pointercast(llslot, bx.type_ptr_to( bx.cast_backend_type(&cast_ty) )); bx.load(addr, self.fn_ty.ret.layout.align.abi) } }; bx.ret(llval); } fn codegen_drop_terminator<'b>( &mut self, helper: TerminatorCodegenHelper<'b, 'tcx>, mut bx: Bx, location: &mir::Place<'tcx>, target: mir::BasicBlock, unwind: Option, ) { let ty = location.ty(self.mir, bx.tcx()).ty; let ty = self.monomorphize(&ty); let drop_fn = monomorphize::resolve_drop_in_place(bx.tcx(), ty); if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def { // we don't actually need to drop anything. helper.funclet_br(self, &mut bx, target); return } let place = self.codegen_place(&mut bx, location); let (args1, args2); let mut args = if let Some(llextra) = place.llextra { args2 = [place.llval, llextra]; &args2[..] } else { args1 = [place.llval]; &args1[..] }; let (drop_fn, fn_ty) = match ty.sty { ty::Dynamic(..) => { let sig = drop_fn.fn_sig(self.cx.tcx()); let sig = self.cx.tcx().normalize_erasing_late_bound_regions( ty::ParamEnv::reveal_all(), &sig, ); let fn_ty = bx.new_vtable(sig, &[]); let vtable = args[1]; args = &args[..1]; (meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_ty), fn_ty) } _ => { (bx.get_fn(drop_fn), bx.fn_type_of_instance(&drop_fn)) } }; helper.do_call(self, &mut bx, fn_ty, drop_fn, args, Some((ReturnDest::Nothing, target)), unwind); } fn codegen_assert_terminator<'b>( &mut self, helper: TerminatorCodegenHelper<'b, 'tcx>, mut bx: Bx, terminator: &mir::Terminator<'tcx>, cond: &mir::Operand<'tcx>, expected: bool, msg: &mir::AssertMessage<'tcx>, target: mir::BasicBlock, cleanup: Option, ) { let span = terminator.source_info.span; let cond = self.codegen_operand(&mut bx, cond).immediate(); let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1); // This case can currently arise only from functions marked // with #[rustc_inherit_overflow_checks] and inlined from // another crate (mostly core::num generic/#[inline] fns), // while the current crate doesn't use overflow checks. // NOTE: Unlike binops, negation doesn't have its own // checked operation, just a comparison with the minimum // value, so we have to check for the assert message. if !bx.check_overflow() { if let mir::interpret::InterpError::OverflowNeg = *msg { const_cond = Some(expected); } } // Don't codegen the panic block if success if known. if const_cond == Some(expected) { helper.funclet_br(self, &mut bx, target); return; } // Pass the condition through llvm.expect for branch hinting. let cond = bx.expect(cond, expected); // Create the failure block and the conditional branch to it. let lltarget = helper.llblock(self, target); let panic_block = self.new_block("panic"); if expected { bx.cond_br(cond, lltarget, panic_block.llbb()); } else { bx.cond_br(cond, panic_block.llbb(), lltarget); } // After this point, bx is the block for the call to panic. bx = panic_block; self.set_debug_loc(&mut bx, terminator.source_info); // Get the location information. let loc = bx.sess().source_map().lookup_char_pos(span.lo()); let filename = Symbol::intern(&loc.file.name.to_string()).as_str(); let line = bx.const_u32(loc.line as u32); let col = bx.const_u32(loc.col.to_usize() as u32 + 1); // Put together the arguments to the panic entry point. let (lang_item, args) = match *msg { InterpError::BoundsCheck { ref len, ref index } => { let len = self.codegen_operand(&mut bx, len).immediate(); let index = self.codegen_operand(&mut bx, index).immediate(); let file_line_col = bx.static_panic_msg( None, filename, line, col, "panic_bounds_check_loc", ); (lang_items::PanicBoundsCheckFnLangItem, vec![file_line_col, index, len]) } _ => { let str = msg.description(); let msg_str = Symbol::intern(str).as_str(); let msg_file_line_col = bx.static_panic_msg( Some(msg_str), filename, line, col, "panic_loc", ); (lang_items::PanicFnLangItem, vec![msg_file_line_col]) } }; // Obtain the panic entry point. let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item); let instance = ty::Instance::mono(bx.tcx(), def_id); let fn_ty = bx.fn_type_of_instance(&instance); let llfn = bx.get_fn(instance); // Codegen the actual panic invoke/call. helper.do_call(self, &mut bx, fn_ty, llfn, &args, None, cleanup); } fn codegen_call_terminator<'b>( &mut self, helper: TerminatorCodegenHelper<'b, 'tcx>, mut bx: Bx, terminator: &mir::Terminator<'tcx>, func: &mir::Operand<'tcx>, args: &Vec>, destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>, cleanup: Option, ) { let span = terminator.source_info.span; // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar. let callee = self.codegen_operand(&mut bx, func); let (instance, mut llfn) = match callee.layout.ty.sty { ty::FnDef(def_id, substs) => { (Some(ty::Instance::resolve(bx.tcx(), ty::ParamEnv::reveal_all(), def_id, substs).unwrap()), None) } ty::FnPtr(_) => { (None, Some(callee.immediate())) } _ => bug!("{} is not callable", callee.layout.ty), }; let def = instance.map(|i| i.def); let sig = callee.layout.ty.fn_sig(bx.tcx()); let sig = bx.tcx().normalize_erasing_late_bound_regions( ty::ParamEnv::reveal_all(), &sig, ); let abi = sig.abi; // Handle intrinsics old codegen wants Expr's for, ourselves. let intrinsic = match def { Some(ty::InstanceDef::Intrinsic(def_id)) => Some(bx.tcx().item_name(def_id).as_str()), _ => None }; let intrinsic = intrinsic.as_ref().map(|s| &s[..]); if intrinsic == Some("transmute") { if let Some(destination_ref) = destination.as_ref() { let &(ref dest, target) = destination_ref; self.codegen_transmute(&mut bx, &args[0], dest); helper.funclet_br(self, &mut bx, target); } else { // If we are trying to transmute to an uninhabited type, // it is likely there is no allotted destination. In fact, // transmuting to an uninhabited type is UB, which means // we can do what we like. Here, we declare that transmuting // into an uninhabited type is impossible, so anything following // it must be unreachable. assert_eq!(bx.layout_of(sig.output()).abi, layout::Abi::Uninhabited); bx.unreachable(); } return; } // The "spoofed" `VaList` added to a C-variadic functions signature // should not be included in the `extra_args` calculation. let extra_args_start_idx = sig.inputs().len() - if sig.c_variadic { 1 } else { 0 }; let extra_args = &args[extra_args_start_idx..]; let extra_args = extra_args.iter().map(|op_arg| { let op_ty = op_arg.ty(self.mir, bx.tcx()); self.monomorphize(&op_ty) }).collect::>(); let fn_ty = match def { Some(ty::InstanceDef::Virtual(..)) => { bx.new_vtable(sig, &extra_args) } Some(ty::InstanceDef::DropGlue(_, None)) => { // Empty drop glue; a no-op. let &(_, target) = destination.as_ref().unwrap(); helper.funclet_br(self, &mut bx, target); return; } _ => bx.new_fn_type(sig, &extra_args) }; // Emit a panic or a no-op for `panic_if_uninhabited`. if intrinsic == Some("panic_if_uninhabited") { let ty = instance.unwrap().substs.type_at(0); let layout = bx.layout_of(ty); if layout.abi.is_uninhabited() { let loc = bx.sess().source_map().lookup_char_pos(span.lo()); let filename = Symbol::intern(&loc.file.name.to_string()).as_str(); let line = bx.const_u32(loc.line as u32); let col = bx.const_u32(loc.col.to_usize() as u32 + 1); let str = format!( "Attempted to instantiate uninhabited type {}", ty ); let msg_str = Symbol::intern(&str).as_str(); let msg_file_line_col = bx.static_panic_msg( Some(msg_str), filename, line, col, "panic_loc", ); // Obtain the panic entry point. let def_id = common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem); let instance = ty::Instance::mono(bx.tcx(), def_id); let fn_ty = bx.fn_type_of_instance(&instance); let llfn = bx.get_fn(instance); // Codegen the actual panic invoke/call. helper.do_call( self, &mut bx, fn_ty, llfn, &[msg_file_line_col], destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)), cleanup, ); } else { // a NOP helper.funclet_br(self, &mut bx, destination.as_ref().unwrap().1) } return; } // The arguments we'll be passing. Plus one to account for outptr, if used. let arg_count = fn_ty.args.len() + fn_ty.ret.is_indirect() as usize; let mut llargs = Vec::with_capacity(arg_count); // Prepare the return value destination let ret_dest = if let Some((ref dest, _)) = *destination { let is_intrinsic = intrinsic.is_some(); self.make_return_dest(&mut bx, dest, &fn_ty.ret, &mut llargs, is_intrinsic) } else { ReturnDest::Nothing }; if intrinsic.is_some() && intrinsic != Some("drop_in_place") { let dest = match ret_dest { _ if fn_ty.ret.is_indirect() => llargs[0], ReturnDest::Nothing => bx.const_undef(bx.type_ptr_to(bx.memory_ty(&fn_ty.ret))), ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) => dst.llval, ReturnDest::DirectOperand(_) => bug!("Cannot use direct operand with an intrinsic call"), }; let args: Vec<_> = args.iter().enumerate().map(|(i, arg)| { // The indices passed to simd_shuffle* in the // third argument must be constant. This is // checked by const-qualification, which also // promotes any complex rvalues to constants. if i == 2 && intrinsic.unwrap().starts_with("simd_shuffle") { match *arg { // The shuffle array argument is usually not an explicit constant, // but specified directly in the code. This means it gets promoted // and we can then extract the value by evaluating the promoted. mir::Operand::Copy( Place::Base( PlaceBase::Static( box Static { kind: StaticKind::Promoted(promoted), ty } ) ) ) | mir::Operand::Move( Place::Base( PlaceBase::Static( box Static { kind: StaticKind::Promoted(promoted), ty } ) ) ) => { let param_env = ty::ParamEnv::reveal_all(); let cid = mir::interpret::GlobalId { instance: self.instance, promoted: Some(promoted), }; let c = bx.tcx().const_eval(param_env.and(cid)); let (llval, ty) = self.simd_shuffle_indices( &bx, terminator.source_info.span, ty, c, ); return OperandRef { val: Immediate(llval), layout: bx.layout_of(ty), }; } mir::Operand::Copy(_) | mir::Operand::Move(_) => { span_bug!(span, "shuffle indices must be constant"); } mir::Operand::Constant(ref constant) => { let c = self.eval_mir_constant(constant); let (llval, ty) = self.simd_shuffle_indices( &bx, constant.span, constant.ty, c, ); return OperandRef { val: Immediate(llval), layout: bx.layout_of(ty) }; } } } self.codegen_operand(&mut bx, arg) }).collect(); let callee_ty = instance.as_ref().unwrap().ty(bx.tcx()); bx.codegen_intrinsic_call(callee_ty, &fn_ty, &args, dest, terminator.source_info.span); if let ReturnDest::IndirectOperand(dst, _) = ret_dest { self.store_return(&mut bx, ret_dest, &fn_ty.ret, dst.llval); } if let Some((_, target)) = *destination { helper.funclet_br(self, &mut bx, target); } else { bx.unreachable(); } return; } // Split the rust-call tupled arguments off. let (first_args, untuple) = if abi == Abi::RustCall && !args.is_empty() { let (tup, args) = args.split_last().unwrap(); (args, Some(tup)) } else { (&args[..], None) }; // Useful determining if the current argument is the "spoofed" `VaList` let last_arg_idx = if sig.inputs().is_empty() { None } else { Some(sig.inputs().len() - 1) }; 'make_args: for (i, arg) in first_args.iter().enumerate() { // If this is a C-variadic function the function signature contains // an "spoofed" `VaList`. This argument is ignored, but we need to // populate it with a dummy operand so that the users real arguments // are not overwritten. let i = if sig.c_variadic && last_arg_idx.map(|x| i >= x).unwrap_or(false) { if i + 1 < fn_ty.args.len() { i + 1 } else { break 'make_args } } else { i }; let mut op = self.codegen_operand(&mut bx, arg); if let (0, Some(ty::InstanceDef::Virtual(_, idx))) = (i, def) { if let Pair(..) = op.val { // In the case of Rc, we need to explicitly pass a // *mut RcBox with a Scalar (not ScalarPair) ABI. This is a hack // that is understood elsewhere in the compiler as a method on // `dyn Trait`. // To get a `*mut RcBox`, we just keep unwrapping newtypes until // we get a value of a built-in pointer type 'descend_newtypes: while !op.layout.ty.is_unsafe_ptr() && !op.layout.ty.is_region_ptr() { 'iter_fields: for i in 0..op.layout.fields.count() { let field = op.extract_field(&mut bx, i); if !field.layout.is_zst() { // we found the one non-zero-sized field that is allowed // now find *its* non-zero-sized field, or stop if it's a // pointer op = field; continue 'descend_newtypes } } span_bug!(span, "receiver has no non-zero-sized fields {:?}", op); } // now that we have `*dyn Trait` or `&dyn Trait`, split it up into its // data pointer and vtable. Look up the method in the vtable, and pass // the data pointer as the first argument match op.val { Pair(data_ptr, meta) => { llfn = Some(meth::VirtualIndex::from_index(idx) .get_fn(&mut bx, meta, &fn_ty)); llargs.push(data_ptr); continue 'make_args } other => bug!("expected a Pair, got {:?}", other), } } else if let Ref(data_ptr, Some(meta), _) = op.val { // by-value dynamic dispatch llfn = Some(meth::VirtualIndex::from_index(idx) .get_fn(&mut bx, meta, &fn_ty)); llargs.push(data_ptr); continue; } else { span_bug!(span, "can't codegen a virtual call on {:?}", op); } } // The callee needs to own the argument memory if we pass it // by-ref, so make a local copy of non-immediate constants. match (arg, op.val) { (&mir::Operand::Copy(_), Ref(_, None, _)) | (&mir::Operand::Constant(_), Ref(_, None, _)) => { let tmp = PlaceRef::alloca(&mut bx, op.layout, "const"); op.val.store(&mut bx, tmp); op.val = Ref(tmp.llval, None, tmp.align); } _ => {} } self.codegen_argument(&mut bx, op, &mut llargs, &fn_ty.args[i]); } if let Some(tup) = untuple { self.codegen_arguments_untupled(&mut bx, tup, &mut llargs, &fn_ty.args[first_args.len()..]) } let fn_ptr = match (llfn, instance) { (Some(llfn), _) => llfn, (None, Some(instance)) => bx.get_fn(instance), _ => span_bug!(span, "no llfn for call"), }; helper.do_call(self, &mut bx, fn_ty, fn_ptr, &llargs, destination.as_ref().map(|&(_, target)| (ret_dest, target)), cleanup); } } impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { pub fn codegen_block( &mut self, bb: mir::BasicBlock, ) { let mut bx = self.build_block(bb); let data = &self.mir[bb]; debug!("codegen_block({:?}={:?})", bb, data); for statement in &data.statements { bx = self.codegen_statement(bx, statement); } self.codegen_terminator(bx, bb, data.terminator()); } fn codegen_terminator( &mut self, mut bx: Bx, bb: mir::BasicBlock, terminator: &mir::Terminator<'tcx> ) { debug!("codegen_terminator: {:?}", terminator); // Create the cleanup bundle, if needed. let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb); let helper = TerminatorCodegenHelper { bb: &bb, terminator, funclet_bb }; self.set_debug_loc(&mut bx, terminator.source_info); match terminator.kind { mir::TerminatorKind::Resume => { self.codegen_resume_terminator(helper, bx) } mir::TerminatorKind::Abort => { bx.abort(); bx.unreachable(); } mir::TerminatorKind::Goto { target } => { helper.funclet_br(self, &mut bx, target); } mir::TerminatorKind::SwitchInt { ref discr, switch_ty, ref values, ref targets } => { self.codegen_switchint_terminator(helper, bx, discr, switch_ty, values, targets); } mir::TerminatorKind::Return => { self.codegen_return_terminator(bx); } mir::TerminatorKind::Unreachable => { bx.unreachable(); } mir::TerminatorKind::Drop { ref location, target, unwind } => { self.codegen_drop_terminator(helper, bx, location, target, unwind); } mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => { self.codegen_assert_terminator(helper, bx, terminator, cond, expected, msg, target, cleanup); } mir::TerminatorKind::DropAndReplace { .. } => { bug!("undesugared DropAndReplace in codegen: {:?}", terminator); } mir::TerminatorKind::Call { ref func, ref args, ref destination, cleanup, from_hir_call: _ } => { self.codegen_call_terminator(helper, bx, terminator, func, args, destination, cleanup); } mir::TerminatorKind::GeneratorDrop | mir::TerminatorKind::Yield { .. } => bug!("generator ops in codegen"), mir::TerminatorKind::FalseEdges { .. } | mir::TerminatorKind::FalseUnwind { .. } => bug!("borrowck false edges in codegen"), } } fn codegen_argument( &mut self, bx: &mut Bx, op: OperandRef<'tcx, Bx::Value>, llargs: &mut Vec, arg: &ArgType<'tcx, Ty<'tcx>> ) { // Fill padding with undef value, where applicable. if let Some(ty) = arg.pad { llargs.push(bx.const_undef(bx.reg_backend_type(&ty))) } if arg.is_ignore() { return; } if let PassMode::Pair(..) = arg.mode { match op.val { Pair(a, b) => { llargs.push(a); llargs.push(b); return; } _ => bug!("codegen_argument: {:?} invalid for pair argument", op) } } else if arg.is_unsized_indirect() { match op.val { Ref(a, Some(b), _) => { llargs.push(a); llargs.push(b); return; } _ => bug!("codegen_argument: {:?} invalid for unsized indirect argument", op) } } // Force by-ref if we have to load through a cast pointer. let (mut llval, align, by_ref) = match op.val { Immediate(_) | Pair(..) => { match arg.mode { PassMode::Indirect(..) | PassMode::Cast(_) => { let scratch = PlaceRef::alloca(bx, arg.layout, "arg"); op.val.store(bx, scratch); (scratch.llval, scratch.align, true) } _ => { (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false) } } } Ref(llval, _, align) => { if arg.is_indirect() && align < arg.layout.align.abi { // `foo(packed.large_field)`. We can't pass the (unaligned) field directly. I // think that ATM (Rust 1.16) we only pass temporaries, but we shouldn't // have scary latent bugs around. let scratch = PlaceRef::alloca(bx, arg.layout, "arg"); base::memcpy_ty(bx, scratch.llval, scratch.align, llval, align, op.layout, MemFlags::empty()); (scratch.llval, scratch.align, true) } else { (llval, align, true) } } }; if by_ref && !arg.is_indirect() { // Have to load the argument, maybe while casting it. if let PassMode::Cast(ty) = arg.mode { let addr = bx.pointercast(llval, bx.type_ptr_to( bx.cast_backend_type(&ty)) ); llval = bx.load(addr, align.min(arg.layout.align.abi)); } else { // We can't use `PlaceRef::load` here because the argument // may have a type we don't treat as immediate, but the ABI // used for this call is passing it by-value. In that case, // the load would just produce `OperandValue::Ref` instead // of the `OperandValue::Immediate` we need for the call. llval = bx.load(llval, align); if let layout::Abi::Scalar(ref scalar) = arg.layout.abi { if scalar.is_bool() { bx.range_metadata(llval, 0..2); } } // We store bools as i8 so we need to truncate to i1. llval = base::to_immediate(bx, llval, arg.layout); } } llargs.push(llval); } fn codegen_arguments_untupled( &mut self, bx: &mut Bx, operand: &mir::Operand<'tcx>, llargs: &mut Vec, args: &[ArgType<'tcx, Ty<'tcx>>] ) { let tuple = self.codegen_operand(bx, operand); // Handle both by-ref and immediate tuples. if let Ref(llval, None, align) = tuple.val { let tuple_ptr = PlaceRef::new_sized(llval, tuple.layout, align); for i in 0..tuple.layout.fields.count() { let field_ptr = tuple_ptr.project_field(bx, i); let field = bx.load_operand(field_ptr); self.codegen_argument(bx, field, llargs, &args[i]); } } else if let Ref(_, Some(_), _) = tuple.val { bug!("closure arguments must be sized") } else { // If the tuple is immediate, the elements are as well. for i in 0..tuple.layout.fields.count() { let op = tuple.extract_field(bx, i); self.codegen_argument(bx, op, llargs, &args[i]); } } } fn get_personality_slot( &mut self, bx: &mut Bx ) -> PlaceRef<'tcx, Bx::Value> { let cx = bx.cx(); if let Some(slot) = self.personality_slot { slot } else { let layout = cx.layout_of(cx.tcx().intern_tup(&[ cx.tcx().mk_mut_ptr(cx.tcx().types.u8), cx.tcx().types.i32 ])); let slot = PlaceRef::alloca(bx, layout, "personalityslot"); self.personality_slot = Some(slot); slot } } /// Returns the landing-pad wrapper around the given basic block. /// /// No-op in MSVC SEH scheme. fn landing_pad_to( &mut self, target_bb: mir::BasicBlock ) -> Bx::BasicBlock { if let Some(block) = self.landing_pads[target_bb] { return block; } let block = self.blocks[target_bb]; let landing_pad = self.landing_pad_uncached(block); self.landing_pads[target_bb] = Some(landing_pad); landing_pad } fn landing_pad_uncached( &mut self, target_bb: Bx::BasicBlock ) -> Bx::BasicBlock { if base::wants_msvc_seh(self.cx.sess()) { span_bug!(self.mir.span, "landing pad was not inserted?") } let mut bx = self.new_block("cleanup"); let llpersonality = self.cx.eh_personality(); let llretty = self.landing_pad_type(); let lp = bx.landing_pad(llretty, llpersonality, 1); bx.set_cleanup(lp); let slot = self.get_personality_slot(&mut bx); slot.storage_live(&mut bx); Pair(bx.extract_value(lp, 0), bx.extract_value(lp, 1)).store(&mut bx, slot); bx.br(target_bb); bx.llbb() } fn landing_pad_type(&self) -> Bx::Type { let cx = self.cx; cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false) } fn unreachable_block( &mut self ) -> Bx::BasicBlock { self.unreachable_block.unwrap_or_else(|| { let mut bx = self.new_block("unreachable"); bx.unreachable(); self.unreachable_block = Some(bx.llbb()); bx.llbb() }) } pub fn new_block(&self, name: &str) -> Bx { Bx::new_block(self.cx, self.llfn, name) } pub fn build_block( &self, bb: mir::BasicBlock ) -> Bx { let mut bx = Bx::with_cx(self.cx); bx.position_at_end(self.blocks[bb]); bx } fn make_return_dest( &mut self, bx: &mut Bx, dest: &mir::Place<'tcx>, fn_ret: &ArgType<'tcx, Ty<'tcx>>, llargs: &mut Vec, is_intrinsic: bool ) -> ReturnDest<'tcx, Bx::Value> { // If the return is ignored, we can just return a do-nothing ReturnDest if fn_ret.is_ignore() { return ReturnDest::Nothing; } let dest = if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dest { match self.locals[index] { LocalRef::Place(dest) => dest, LocalRef::UnsizedPlace(_) => bug!("return type must be sized"), LocalRef::Operand(None) => { // Handle temporary places, specifically Operand ones, as // they don't have allocas return if fn_ret.is_indirect() { // Odd, but possible, case, we have an operand temporary, // but the calling convention has an indirect return. let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret"); tmp.storage_live(bx); llargs.push(tmp.llval); ReturnDest::IndirectOperand(tmp, index) } else if is_intrinsic { // Currently, intrinsics always need a location to store // the result. so we create a temporary alloca for the // result let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret"); tmp.storage_live(bx); ReturnDest::IndirectOperand(tmp, index) } else { ReturnDest::DirectOperand(index) }; } LocalRef::Operand(Some(_)) => { bug!("place local already assigned to"); } } } else { self.codegen_place(bx, dest) }; if fn_ret.is_indirect() { if dest.align < dest.layout.align.abi { // Currently, MIR code generation does not create calls // that store directly to fields of packed structs (in // fact, the calls it creates write only to temps), // // If someone changes that, please update this code path // to create a temporary. span_bug!(self.mir.span, "can't directly store to unaligned value"); } llargs.push(dest.llval); ReturnDest::Nothing } else { ReturnDest::Store(dest) } } fn codegen_transmute( &mut self, bx: &mut Bx, src: &mir::Operand<'tcx>, dst: &mir::Place<'tcx> ) { if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dst { match self.locals[index] { LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place), LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"), LocalRef::Operand(None) => { let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst)); assert!(!dst_layout.ty.has_erasable_regions()); let place = PlaceRef::alloca(bx, dst_layout, "transmute_temp"); place.storage_live(bx); self.codegen_transmute_into(bx, src, place); let op = bx.load_operand(place); place.storage_dead(bx); self.locals[index] = LocalRef::Operand(Some(op)); } LocalRef::Operand(Some(op)) => { assert!(op.layout.is_zst(), "assigning to initialized SSAtemp"); } } } else { let dst = self.codegen_place(bx, dst); self.codegen_transmute_into(bx, src, dst); } } fn codegen_transmute_into( &mut self, bx: &mut Bx, src: &mir::Operand<'tcx>, dst: PlaceRef<'tcx, Bx::Value> ) { let src = self.codegen_operand(bx, src); let llty = bx.backend_type(src.layout); let cast_ptr = bx.pointercast(dst.llval, bx.type_ptr_to(llty)); let align = src.layout.align.abi.min(dst.align); src.val.store(bx, PlaceRef::new_sized(cast_ptr, src.layout, align)); } // Stores the return value of a function call into it's final location. fn store_return( &mut self, bx: &mut Bx, dest: ReturnDest<'tcx, Bx::Value>, ret_ty: &ArgType<'tcx, Ty<'tcx>>, llval: Bx::Value ) { use self::ReturnDest::*; match dest { Nothing => (), Store(dst) => bx.store_arg_ty(&ret_ty, llval, dst), IndirectOperand(tmp, index) => { let op = bx.load_operand(tmp); tmp.storage_dead(bx); self.locals[index] = LocalRef::Operand(Some(op)); } DirectOperand(index) => { // If there is a cast, we have to store and reload. let op = if let PassMode::Cast(_) = ret_ty.mode { let tmp = PlaceRef::alloca(bx, ret_ty.layout, "tmp_ret"); tmp.storage_live(bx); bx.store_arg_ty(&ret_ty, llval, tmp); let op = bx.load_operand(tmp); tmp.storage_dead(bx); op } else { OperandRef::from_immediate_or_packed_pair(bx, llval, ret_ty.layout) }; self.locals[index] = LocalRef::Operand(Some(op)); } } } } enum ReturnDest<'tcx, V> { // Do nothing, the return value is indirect or ignored Nothing, // Store the return value to the pointer Store(PlaceRef<'tcx, V>), // Stores an indirect return value to an operand local place IndirectOperand(PlaceRef<'tcx, V>, mir::Local), // Stores a direct return value to an operand local place DirectOperand(mir::Local) }