diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs index ce59bf1d61d..23a5b0cf32a 100644 --- a/src/librustc_codegen_ssa/mir/block.rs +++ b/src/librustc_codegen_ssa/mir/block.rs @@ -362,7 +362,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { } }; helper.maybe_sideeffect(self.mir, &mut bx, &[target]); - helper.do_call(self, &mut bx, fn_ty, drop_fn, args, + helper.do_call(self, &mut bx, fn_abi, drop_fn, args, Some((ReturnDest::Nothing, target)), unwind); } @@ -779,7 +779,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { if let Some((_, target)) = destination.as_ref() { helper.maybe_sideeffect(self.mir, &mut bx, &[*target]); } - helper.do_call(self, &mut bx, fn_ty, fn_ptr, &llargs, + helper.do_call(self, &mut bx, fn_abi, fn_ptr, &llargs, destination.as_ref().map(|&(_, target)| (ret_dest, target)), cleanup); } diff --git a/src/librustc_codegen_ssa/mir/block.rs.orig b/src/librustc_codegen_ssa/mir/block.rs.orig new file mode 100644 index 00000000000..d715a4e0e09 --- /dev/null +++ b/src/librustc_codegen_ssa/mir/block.rs.orig @@ -0,0 +1,1257 @@ +use rustc_index::vec::Idx; +use rustc::middle::lang_items; +use rustc::ty::{self, Ty, TypeFoldable, Instance}; +use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, FnAbiExt}; +use rustc::mir::{self, PlaceBase, Static, StaticKind}; +use rustc::mir::interpret::PanicInfo; +use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode}; +use rustc_target::spec::abi::Abi; +use crate::base; +use crate::MemFlags; +use crate::common::{self, IntPredicate}; +use crate::meth; + +use crate::traits::*; + +use std::borrow::Cow; + +use syntax::{source_map::Span, symbol::Symbol}; + +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_abi` 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_abi: FnAbi<'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_abi, 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_abi.ret, invokeret); + } + } else { + let llret = bx.call(fn_ptr, &llargs, self.funclet(fx)); + bx.apply_attrs_callsite(&fn_abi, 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_abi.ret, llret); + self.funclet_br(fx, bx, target); + } else { + bx.unreachable(); + } + } + } + + // Generate sideeffect intrinsic if jumping to any of the targets can form + // a loop. + fn maybe_sideeffect<'b, 'tcx2: 'b, Bx: BuilderMethods<'b, 'tcx2>>( + &self, + mir: mir::ReadOnlyBodyCache<'b, 'tcx>, + bx: &mut Bx, + targets: &[mir::BasicBlock], + ) { + if bx.tcx().sess.opts.debugging_opts.insert_sideeffect { + if targets.iter().any(|target| { + *target <= *self.bb + && target + .start_location() + .is_predecessor_of(self.bb.start_location(), mir) + }) { + bx.sideeffect(); + } + } + } +} + +/// Codegen implementations for some terminator variants. +impl<'a, 'tcx, 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 { + helper.maybe_sideeffect(self.mir, &mut bx, targets.as_slice()); + // 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); + helper.maybe_sideeffect(self.mir, &mut bx, targets.as_slice()); + bx.cond_br(cmp, lltrue, llfalse); + } + } else { + helper.maybe_sideeffect(self.mir, &mut bx, targets.as_slice()); + 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(&mut self, mut bx: Bx) { + // Call `va_end` if this is the definition of a C-variadic function. + if self.fn_abi.c_variadic { + // The `VaList` "spoofed" argument is just after all the real arguments. + let va_list_arg_idx = self.fn_abi.args.len(); + match self.locals[mir::Local::new(1 + va_list_arg_idx)] { + LocalRef::Place(va_list) => { + bx.va_end(va_list.llval); + } + _ => bug!("C-variadic function must have a `VaList` place"), + } + } + if self.fn_abi.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_abi.ret.mode { + PassMode::Ignore | PassMode::Indirect(..) => { + bx.ret_void(); + return; + } + + PassMode::Direct(_) | PassMode::Pair(..) => { + let op = + self.codegen_consume(&mut bx, &mir::Place::return_place().as_ref()); + 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_abi.ret.layout); + 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_abi.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.body(), bx.tcx()).ty; + let ty = self.monomorphize(&ty); + let drop_fn = Instance::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.maybe_sideeffect(self.mir, &mut bx, &[target]); + helper.funclet_br(self, &mut bx, target); + return + } + + let place = self.codegen_place(&mut bx, &location.as_ref()); + 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_abi) = match ty.kind { + 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_abi = FnAbi::new_vtable(&bx, sig, &[]); + let vtable = args[1]; + args = &args[..1]; + (meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_abi), fn_abi) + } + _ => { + (bx.get_fn_addr(drop_fn), + FnAbi::of_instance(&bx, drop_fn)) + } + }; + helper.maybe_sideeffect(self.mir, &mut bx, &[target]); + 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 PanicInfo::OverflowNeg = *msg { + const_cond = Some(expected); + } + } + + // Don't codegen the panic block if success if known. + if const_cond == Some(expected) { + helper.maybe_sideeffect(self.mir, &mut bx, &[target]); + 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"); + helper.maybe_sideeffect(self.mir, &mut bx, &[target]); + 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 location = self.get_caller_location(&mut bx, span).immediate(); + + // Put together the arguments to the panic entry point. + let (lang_item, args) = match msg { + PanicInfo::BoundsCheck { ref len, ref index } => { + let len = self.codegen_operand(&mut bx, len).immediate(); + let index = self.codegen_operand(&mut bx, index).immediate(); + (lang_items::PanicBoundsCheckFnLangItem, vec![location, index, len]) + } + _ => { + let msg_str = Symbol::intern(msg.description()); + let msg = bx.const_str(msg_str); + (lang_items::PanicFnLangItem, vec![msg.0, msg.1, location]) + } + }; + + // 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_abi = FnAbi::of_instance(&bx, instance); + let llfn = bx.get_fn_addr(instance); + + // Codegen the actual panic invoke/call. + helper.do_call(self, &mut bx, fn_abi, 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.kind { + 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.maybe_sideeffect(self.mir, &mut bx, &[target]); + 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; + } + + let extra_args = &args[sig.inputs().len()..]; + let extra_args = extra_args.iter().map(|op_arg| { + let op_ty = op_arg.ty(self.mir.body(), bx.tcx()); + self.monomorphize(&op_ty) + }).collect::>(); + + let fn_abi = match def { + Some(ty::InstanceDef::Virtual(..)) => { + FnAbi::new_vtable(&bx, sig, &extra_args) + } + Some(ty::InstanceDef::DropGlue(_, None)) => { + // Empty drop glue; a no-op. + let &(_, target) = destination.as_ref().unwrap(); + helper.maybe_sideeffect(self.mir, &mut bx, &[target]); + helper.funclet_br(self, &mut bx, target); + return; + } + _ => FnAbi::new(&bx, 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 msg_str = format!("Attempted to instantiate uninhabited type {}", ty); + let msg = bx.const_str(Symbol::intern(&msg_str)); + let location = self.get_caller_location(&mut bx, span).immediate(); + + // 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_abi = FnAbi::of_instance(&bx, instance); + let llfn = bx.get_fn_addr(instance); + + if let Some((_, target)) = destination.as_ref() { + helper.maybe_sideeffect(self.mir, &mut bx, &[*target]); + } + // Codegen the actual panic invoke/call. + helper.do_call( + self, + &mut bx, + fn_abi, + llfn, + &[msg.0, msg.1, location], + destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)), + cleanup, + ); + } else { + // a NOP + let target = destination.as_ref().unwrap().1; + helper.maybe_sideeffect(self.mir, &mut bx, &[target]); + 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_abi.args.len() + fn_abi.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(); +<<<<<<< HEAD + self.make_return_dest(&mut bx, dest, &fn_abi.ret, &mut llargs, is_intrinsic) +======= + self.make_return_dest(&mut bx, dest, &fn_ty.ret, &mut llargs, + is_intrinsic) +>>>>>>> Undo minor changes that weren't needed, fix one lifetime typo + } else { + ReturnDest::Nothing + }; + + if intrinsic == Some("caller_location") { + if let Some((_, target)) = destination.as_ref() { + let location = self.get_caller_location(&mut bx, span); + + if let ReturnDest::IndirectOperand(tmp, _) = ret_dest { + location.val.store(&mut bx, tmp); + } + self.store_return(&mut bx, ret_dest, &fn_abi.ret, location.immediate()); + + helper.maybe_sideeffect(self.mir, &mut bx, &[*target]); + helper.funclet_br(self, &mut bx, *target); + } + return; + } + + if intrinsic.is_some() && intrinsic != Some("drop_in_place") { + let dest = match ret_dest { + _ if fn_abi.ret.is_indirect() => llargs[0], + ReturnDest::Nothing => + bx.const_undef(bx.type_ptr_to(bx.arg_memory_ty(&fn_abi.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) | mir::Operand::Move(place) => { + if let mir::PlaceRef { + base: + &PlaceBase::Static(box Static { + kind: StaticKind::Promoted(promoted, _), + ty, + def_id: _, + }), + projection: &[], + } = place.as_ref() + { + 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), + }; + } else { + span_bug!(span, "shuffle indices must be constant"); + } + } + + mir::Operand::Constant(constant) => { + let c = self.eval_mir_constant(constant); + let (llval, ty) = self.simd_shuffle_indices( + &bx, + constant.span, + constant.literal.ty, + c, + ); + return OperandRef { + val: Immediate(llval), + layout: bx.layout_of(ty) + }; + } + } + } + + self.codegen_operand(&mut bx, arg) + }).collect(); + + + bx.codegen_intrinsic_call(*instance.as_ref().unwrap(), &fn_abi, &args, dest, + terminator.source_info.span); + + if let ReturnDest::IndirectOperand(dst, _) = ret_dest { + self.store_return(&mut bx, ret_dest, &fn_abi.ret, dst.llval); + } + + if let Some((_, target)) = *destination { + helper.maybe_sideeffect(self.mir, &mut bx, &[target]); + 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) + }; + + 'make_args: for (i, arg) in first_args.iter().enumerate() { + 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_abi)); + 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_abi)); + 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); + op.val.store(&mut bx, tmp); + op.val = Ref(tmp.llval, None, tmp.align); + } + _ => {} + } + + self.codegen_argument(&mut bx, op, &mut llargs, &fn_abi.args[i]); + } + if let Some(tup) = untuple { + self.codegen_arguments_untupled(&mut bx, tup, &mut llargs, + &fn_abi.args[first_args.len()..]) + } + + let fn_ptr = match (llfn, instance) { + (Some(llfn), _) => llfn, + (None, Some(instance)) => bx.get_fn_addr(instance), + _ => span_bug!(span, "no llfn for call"), + }; + + if let Some((_, target)) = destination.as_ref() { + helper.maybe_sideeffect(self.mir, &mut bx, &[*target]); + } + helper.do_call(self, &mut bx, fn_ty, fn_ptr, &llargs, + destination.as_ref().map(|&(_, target)| (ret_dest, target)), + cleanup); + } +} + +impl<'a, 'tcx, 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.body()[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.maybe_sideeffect(self.mir, &mut bx, &[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: &ArgAbi<'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); + 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); + 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: &[ArgAbi<'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_aligned(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_caller_location( + &mut self, + bx: &mut Bx, + span: Span, + ) -> OperandRef<'tcx, Bx::Value> { + let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span); + let caller = bx.tcx().sess.source_map().lookup_char_pos(topmost.lo()); + let const_loc = bx.tcx().const_caller_location(( + Symbol::intern(&caller.file.name.to_string()), + caller.line as u32, + caller.col_display as u32 + 1, + )); + OperandRef::from_const(bx, const_loc) + } + + 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); + 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>, +<<<<<<< HEAD + fn_ret: &ArgAbi<'tcx, Ty<'tcx>>, + llargs: &mut Vec, is_intrinsic: bool, +======= + fn_ret: &ArgType<'tcx, Ty<'tcx>>, + llargs: &mut Vec, is_intrinsic: bool +>>>>>>> Undo minor changes that weren't needed, fix one lifetime typo + ) -> 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 Some(index) = dest.as_local() { + 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 `alloca`s. + 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.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.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, &mir::PlaceRef { + base: &dest.base, + projection: &dest.projection, + }) + }; + 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 Some(index) = dst.as_local() { + 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.as_ref())); + assert!(!dst_layout.ty.has_erasable_regions()); + let place = PlaceRef::alloca(bx, dst_layout); + 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.as_ref()); + 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_aligned(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_abi: &ArgAbi<'tcx, Ty<'tcx>>, + llval: Bx::Value + ) { + use self::ReturnDest::*; + + match dest { + Nothing => (), + Store(dst) => bx.store_arg(&ret_abi, 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_abi.mode { + let tmp = PlaceRef::alloca(bx, ret_abi.layout); + tmp.storage_live(bx); + bx.store_arg(&ret_abi, llval, tmp); + let op = bx.load_operand(tmp); + tmp.storage_dead(bx); + op + } else { + OperandRef::from_immediate_or_packed_pair(bx, llval, ret_abi.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>), + // Store an indirect return value to an operand local place. + IndirectOperand(PlaceRef<'tcx, V>, mir::Local), + // Store a direct return value to an operand local place. + DirectOperand(mir::Local) +} diff --git a/src/librustc_codegen_ssa/mir/mod.rs.orig b/src/librustc_codegen_ssa/mir/mod.rs.orig new file mode 100644 index 00000000000..83365f2ab22 --- /dev/null +++ b/src/librustc_codegen_ssa/mir/mod.rs.orig @@ -0,0 +1,439 @@ +use rustc::ty::{self, Ty, TypeFoldable, Instance}; +<<<<<<< HEAD +use rustc::ty::layout::{TyLayout, HasTyCtxt, FnAbiExt}; +use rustc::mir::{self, Body, BodyCache}; +use rustc_target::abi::call::{FnAbi, PassMode}; +======= +use rustc::ty::layout::{TyLayout, HasTyCtxt, FnTypeExt}; +use rustc::mir::{self, Body, ReadOnlyBodyCache}; +use rustc_target::abi::call::{FnType, PassMode}; +>>>>>>> Simplify BodyCache impl and fix all remaining type errors in librustc_mir (lifetime errors still exist) +use crate::base; +use crate::traits::*; + +use std::iter; + +use rustc_index::bit_set::BitSet; +use rustc_index::vec::IndexVec; + +use self::analyze::CleanupKind; +use self::debuginfo::FunctionDebugContext; +use self::place::PlaceRef; +use rustc::mir::traversal; + +use self::operand::{OperandRef, OperandValue}; + +/// Master context for codegenning from MIR. +pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> { + instance: Instance<'tcx>, + + mir: mir::ReadOnlyBodyCache<'a, 'tcx>, + + debug_context: Option>, + + llfn: Bx::Function, + + cx: &'a Bx::CodegenCx, + + fn_abi: FnAbi<'tcx, Ty<'tcx>>, + + /// When unwinding is initiated, we have to store this personality + /// value somewhere so that we can load it and re-use it in the + /// resume instruction. The personality is (afaik) some kind of + /// value used for C++ unwinding, which must filter by type: we + /// don't really care about it very much. Anyway, this value + /// contains an alloca into which the personality is stored and + /// then later loaded when generating the DIVERGE_BLOCK. + personality_slot: Option>, + + /// A `Block` for each MIR `BasicBlock` + blocks: IndexVec, + + /// The funclet status of each basic block + cleanup_kinds: IndexVec, + + /// When targeting MSVC, this stores the cleanup info for each funclet + /// BB. This is initialized as we compute the funclets' head block in RPO. + funclets: IndexVec>, + + /// This stores the landing-pad block for a given BB, computed lazily on GNU + /// and eagerly on MSVC. + landing_pads: IndexVec>, + + /// Cached unreachable block + unreachable_block: Option, + + /// The location where each MIR arg/var/tmp/ret is stored. This is + /// usually an `PlaceRef` representing an alloca, but not always: + /// sometimes we can skip the alloca and just store the value + /// directly using an `OperandRef`, which makes for tighter LLVM + /// IR. The conditions for using an `OperandRef` are as follows: + /// + /// - the type of the local must be judged "immediate" by `is_llvm_immediate` + /// - the operand must never be referenced indirectly + /// - we should not take its address using the `&` operator + /// - nor should it appear in a place path like `tmp.a` + /// - the operand must be defined by an rvalue that can generate immediate + /// values + /// + /// Avoiding allocs can also be important for certain intrinsics, + /// notably `expect`. + locals: IndexVec>, + + per_local_var_debug_info: Option>>>, +} + +impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { + pub fn monomorphize(&self, value: &T) -> T + where T: TypeFoldable<'tcx> + { + self.cx.tcx().subst_and_normalize_erasing_regions( + self.instance.substs, + ty::ParamEnv::reveal_all(), + value, + ) + } +} + +enum LocalRef<'tcx, V> { + Place(PlaceRef<'tcx, V>), + /// `UnsizedPlace(p)`: `p` itself is a thin pointer (indirect place). + /// `*p` is the fat pointer that references the actual unsized place. + /// Every time it is initialized, we have to reallocate the place + /// and update the fat pointer. That's the reason why it is indirect. + UnsizedPlace(PlaceRef<'tcx, V>), + Operand(Option>), +} + +impl<'a, 'tcx, V: CodegenObject> LocalRef<'tcx, V> { + fn new_operand>( + bx: &mut Bx, + layout: TyLayout<'tcx>, + ) -> LocalRef<'tcx, V> { + if layout.is_zst() { + // Zero-size temporaries aren't always initialized, which + // doesn't matter because they don't contain data, but + // we need something in the operand. + LocalRef::Operand(Some(OperandRef::new_zst(bx, layout))) + } else { + LocalRef::Operand(None) + } + } +} + +/////////////////////////////////////////////////////////////////////////// + +pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + cx: &'a Bx::CodegenCx, + llfn: Bx::Function, + mir: ReadOnlyBodyCache<'a, 'tcx>, + instance: Instance<'tcx>, + sig: ty::FnSig<'tcx>, +) { + assert!(!instance.substs.needs_infer()); + + let fn_abi = FnAbi::new(cx, sig, &[]); + debug!("fn_abi: {:?}", fn_abi); + + let debug_context = + cx.create_function_debug_context(instance, sig, llfn, &mir); + + let mut bx = Bx::new_block(cx, llfn, "start"); + + if mir.basic_blocks().iter().any(|bb| bb.is_cleanup) { + bx.set_personality_fn(cx.eh_personality()); + } + + bx.sideeffect(); + + let cleanup_kinds = analyze::cleanup_kinds(&mir); + // Allocate a `Block` for every basic block, except + // the start block, if nothing loops back to it. + let reentrant_start_block = !mir.predecessors_for(mir::START_BLOCK).is_empty(); + let block_bxs: IndexVec = + mir.basic_blocks().indices().map(|bb| { + if bb == mir::START_BLOCK && !reentrant_start_block { + bx.llbb() + } else { + bx.build_sibling_block(&format!("{:?}", bb)).llbb() + } + }).collect(); + + let (landing_pads, funclets) = create_funclets(&mir, &mut bx, &cleanup_kinds, &block_bxs); + let mir_body = mir.body(); + let mut fx = FunctionCx { + instance, + mir, + llfn, + fn_abi, + cx, + personality_slot: None, + blocks: block_bxs, + unreachable_block: None, + cleanup_kinds, + landing_pads, + funclets, + locals: IndexVec::new(), + debug_context, + per_local_var_debug_info: debuginfo::per_local_var_debug_info(cx.tcx(), mir), + }; + + let memory_locals = analyze::non_ssa_locals(&fx); + + // Allocate variable and temp allocas + fx.locals = { + let args = arg_local_refs(&mut bx, &fx, &memory_locals); + + let mut allocate_local = |local| { + let decl = &mir_body.local_decls[local]; + let layout = bx.layout_of(fx.monomorphize(&decl.ty)); + assert!(!layout.ty.has_erasable_regions()); + + if local == mir::RETURN_PLACE && fx.fn_abi.ret.is_indirect() { + debug!("alloc: {:?} (return place) -> place", local); + let llretptr = bx.get_param(0); + return LocalRef::Place(PlaceRef::new_sized(llretptr, layout)); + } + + if memory_locals.contains(local) { + debug!("alloc: {:?} -> place", local); + if layout.is_unsized() { + LocalRef::UnsizedPlace(PlaceRef::alloca_unsized_indirect(&mut bx, layout)) + } else { + LocalRef::Place(PlaceRef::alloca(&mut bx, layout)) + } + } else { + debug!("alloc: {:?} -> operand", local); + LocalRef::new_operand(&mut bx, layout) + } + }; + + let retptr = allocate_local(mir::RETURN_PLACE); + iter::once(retptr) + .chain(args.into_iter()) + .chain(mir_body.vars_and_temps_iter().map(allocate_local)) + .collect() + }; + + // Apply debuginfo to the newly allocated locals. + fx.debug_introduce_locals(&mut bx); + + // Branch to the START block, if it's not the entry block. + if reentrant_start_block { + bx.br(fx.blocks[mir::START_BLOCK]); + } + + // Up until here, IR instructions for this function have explicitly not been annotated with + // source code location, so we don't step into call setup code. From here on, source location + // emitting should be enabled. + if let Some(debug_context) = &mut fx.debug_context { + debug_context.source_locations_enabled = true; + } + + let rpo = traversal::reverse_postorder(&mir_body); + let mut visited = BitSet::new_empty(mir_body.basic_blocks().len()); + + // Codegen the body of each block using reverse postorder + for (bb, _) in rpo { + visited.insert(bb.index()); + fx.codegen_block(bb); + } + + // Remove blocks that haven't been visited, or have no + // predecessors. + for bb in mir_body.basic_blocks().indices() { + // Unreachable block + if !visited.contains(bb.index()) { + debug!("codegen_mir: block {:?} was not visited", bb); + unsafe { + bx.delete_basic_block(fx.blocks[bb]); + } + } + } +} + +fn create_funclets<'a, 'b, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + mir: &'b Body<'tcx>, + bx: &mut Bx, + cleanup_kinds: &IndexVec, + block_bxs: &IndexVec, +) -> ( + IndexVec>, + IndexVec>, +) { + block_bxs.iter_enumerated().zip(cleanup_kinds).map(|((bb, &llbb), cleanup_kind)| { + match *cleanup_kind { + CleanupKind::Funclet if base::wants_msvc_seh(bx.sess()) => {} + _ => return (None, None) + } + + let funclet; + let ret_llbb; + match mir[bb].terminator.as_ref().map(|t| &t.kind) { + // This is a basic block that we're aborting the program for, + // notably in an `extern` function. These basic blocks are inserted + // so that we assert that `extern` functions do indeed not panic, + // and if they do we abort the process. + // + // On MSVC these are tricky though (where we're doing funclets). If + // we were to do a cleanuppad (like below) the normal functions like + // `longjmp` would trigger the abort logic, terminating the + // program. Instead we insert the equivalent of `catch(...)` for C++ + // which magically doesn't trigger when `longjmp` files over this + // frame. + // + // Lots more discussion can be found on #48251 but this codegen is + // modeled after clang's for: + // + // try { + // foo(); + // } catch (...) { + // bar(); + // } + Some(&mir::TerminatorKind::Abort) => { + let mut cs_bx = bx.build_sibling_block(&format!("cs_funclet{:?}", bb)); + let mut cp_bx = bx.build_sibling_block(&format!("cp_funclet{:?}", bb)); + ret_llbb = cs_bx.llbb(); + + let cs = cs_bx.catch_switch(None, None, 1); + cs_bx.add_handler(cs, cp_bx.llbb()); + + // The "null" here is actually a RTTI type descriptor for the + // C++ personality function, but `catch (...)` has no type so + // it's null. The 64 here is actually a bitfield which + // represents that this is a catch-all block. + let null = bx.const_null(bx.type_i8p()); + let sixty_four = bx.const_i32(64); + funclet = cp_bx.catch_pad(cs, &[null, sixty_four, null]); + cp_bx.br(llbb); + } + _ => { + let mut cleanup_bx = bx.build_sibling_block(&format!("funclet_{:?}", bb)); + ret_llbb = cleanup_bx.llbb(); + funclet = cleanup_bx.cleanup_pad(None, &[]); + cleanup_bx.br(llbb); + } + }; + + (Some(ret_llbb), Some(funclet)) + }).unzip() +} + +/// Produces, for each argument, a `Value` pointing at the +/// argument's value. As arguments are places, these are always +/// indirect. +fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + fx: &FunctionCx<'a, 'tcx, Bx>, + memory_locals: &BitSet, +) -> Vec> { + let mut idx = 0; + let mut llarg_idx = fx.fn_abi.ret.is_indirect() as usize; + + fx.mir.args_iter().enumerate().map(|(arg_index, local)| { + let arg_decl = &fx.mir.local_decls[local]; + + if Some(local) == fx.mir.spread_arg { + // This argument (e.g., the last argument in the "rust-call" ABI) + // is a tuple that was spread at the ABI level and now we have + // to reconstruct it into a tuple local variable, from multiple + // individual LLVM function arguments. + + let arg_ty = fx.monomorphize(&arg_decl.ty); + let tupled_arg_tys = match arg_ty.kind { + ty::Tuple(ref tys) => tys, + _ => bug!("spread argument isn't a tuple?!") + }; + + let place = PlaceRef::alloca(bx, bx.layout_of(arg_ty)); + for i in 0..tupled_arg_tys.len() { + let arg = &fx.fn_abi.args[idx]; + idx += 1; + if arg.pad.is_some() { + llarg_idx += 1; + } + let pr_field = place.project_field(bx, i); + bx.store_fn_arg(arg, &mut llarg_idx, pr_field); + } + + return LocalRef::Place(place); + } + + if fx.fn_abi.c_variadic && arg_index == fx.fn_abi.args.len() { + let arg_ty = fx.monomorphize(&arg_decl.ty); + + let va_list = PlaceRef::alloca(bx, bx.layout_of(arg_ty)); + bx.va_start(va_list.llval); + + return LocalRef::Place(va_list); + } + + let arg = &fx.fn_abi.args[idx]; + idx += 1; + if arg.pad.is_some() { + llarg_idx += 1; + } + + if !memory_locals.contains(local) { + // We don't have to cast or keep the argument in the alloca. + // FIXME(eddyb): We should figure out how to use llvm.dbg.value instead + // of putting everything in allocas just so we can use llvm.dbg.declare. + let local = |op| LocalRef::Operand(Some(op)); + match arg.mode { + PassMode::Ignore => { + return local(OperandRef::new_zst(bx, arg.layout)); + } + PassMode::Direct(_) => { + let llarg = bx.get_param(llarg_idx); + llarg_idx += 1; + return local( + OperandRef::from_immediate_or_packed_pair(bx, llarg, arg.layout)); + } + PassMode::Pair(..) => { + let (a, b) = (bx.get_param(llarg_idx), bx.get_param(llarg_idx + 1)); + llarg_idx += 2; + + return local(OperandRef { + val: OperandValue::Pair(a, b), + layout: arg.layout + }); + } + _ => {} + } + } + + if arg.is_sized_indirect() { + // Don't copy an indirect argument to an alloca, the caller + // already put it in a temporary alloca and gave it up. + // FIXME: lifetimes + let llarg = bx.get_param(llarg_idx); + llarg_idx += 1; + LocalRef::Place(PlaceRef::new_sized(llarg, arg.layout)) + } else if arg.is_unsized_indirect() { + // As the storage for the indirect argument lives during + // the whole function call, we just copy the fat pointer. + let llarg = bx.get_param(llarg_idx); + llarg_idx += 1; + let llextra = bx.get_param(llarg_idx); + llarg_idx += 1; + let indirect_operand = OperandValue::Pair(llarg, llextra); + + let tmp = PlaceRef::alloca_unsized_indirect(bx, arg.layout); + indirect_operand.store(bx, tmp); + LocalRef::UnsizedPlace(tmp) + } else { + let tmp = PlaceRef::alloca(bx, arg.layout); + bx.store_fn_arg(arg, &mut llarg_idx, tmp); + LocalRef::Place(tmp) + } + }).collect() +} + +mod analyze; +mod block; +pub mod constant; +pub mod debuginfo; +pub mod place; +pub mod operand; +mod rvalue; +mod statement;