From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- compiler/rustc_codegen_ssa/src/mir/block.rs | 1654 +++++++++++++++++++++++++++ 1 file changed, 1654 insertions(+) create mode 100644 compiler/rustc_codegen_ssa/src/mir/block.rs (limited to 'compiler/rustc_codegen_ssa/src/mir/block.rs') diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs new file mode 100644 index 000000000..3eee58d9d --- /dev/null +++ b/compiler/rustc_codegen_ssa/src/mir/block.rs @@ -0,0 +1,1654 @@ +use super::operand::OperandRef; +use super::operand::OperandValue::{Immediate, Pair, Ref}; +use super::place::PlaceRef; +use super::{FunctionCx, LocalRef}; + +use crate::base; +use crate::common::{self, IntPredicate}; +use crate::meth; +use crate::traits::*; +use crate::MemFlags; + +use rustc_ast as ast; +use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece}; +use rustc_hir::lang_items::LangItem; +use rustc_index::vec::Idx; +use rustc_middle::mir::AssertKind; +use rustc_middle::mir::{self, SwitchTargets}; +use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf}; +use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths}; +use rustc_middle::ty::{self, Instance, Ty, TypeVisitable}; +use rustc_span::source_map::Span; +use rustc_span::{sym, Symbol}; +use rustc_symbol_mangling::typeid::typeid_for_fnabi; +use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode}; +use rustc_target::abi::{self, HasDataLayout, WrappingRange}; +use rustc_target::spec::abi::Abi; + +/// Used by `FunctionCx::codegen_terminator` for emitting common patterns +/// e.g., creating a basic block, calling a function, etc. +struct TerminatorCodegenHelper<'tcx> { + bb: mir::BasicBlock, + terminator: &'tcx mir::Terminator<'tcx>, + funclet_bb: Option, +} + +impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> { + /// Returns the appropriate `Funclet` for the current funclet, if on MSVC, + /// either already previously cached, or newly created, by `landing_pad_for`. + fn funclet<'b, Bx: BuilderMethods<'a, 'tcx>>( + &self, + fx: &'b mut FunctionCx<'a, 'tcx, Bx>, + ) -> Option<&'b Bx::Funclet> { + let funclet_bb = self.funclet_bb?; + if base::wants_msvc_seh(fx.cx.tcx().sess) { + // If `landing_pad_for` hasn't been called yet to create the `Funclet`, + // it has to be now. This may not seem necessary, as RPO should lead + // to all the unwind edges being visited (and so to `landing_pad_for` + // getting called for them), before building any of the blocks inside + // the funclet itself - however, if MIR contains edges that end up not + // being needed in the LLVM IR after monomorphization, the funclet may + // be unreachable, and we don't have yet a way to skip building it in + // such an eventuality (which may be a better solution than this). + if fx.funclets[funclet_bb].is_none() { + fx.landing_pad_for(funclet_bb); + } + + Some( + fx.funclets[funclet_bb] + .as_ref() + .expect("landing_pad_for didn't also create funclets entry"), + ) + } else { + None + } + } + + fn lltarget>( + &self, + fx: &mut FunctionCx<'a, 'tcx, Bx>, + target: mir::BasicBlock, + ) -> (Bx::BasicBlock, bool) { + let span = self.terminator.source_info.span; + let lltarget = fx.llbb(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, cleanup pad if MSVC + (None, Some(_)) => (fx.landing_pad_for(target), false), + (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator), + (Some(_), Some(_)) => (fx.landing_pad_for(target), true), + } + } + + /// Create a basic block. + fn llblock>( + &self, + fx: &mut FunctionCx<'a, '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 trampoline = Bx::append_block(fx.cx, fx.llfn, name); + let mut trampoline_bx = Bx::build(fx.cx, trampoline); + trampoline_bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget)); + trampoline + } else { + lltarget + } + } + + fn funclet_br>( + &self, + fx: &mut FunctionCx<'a, '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>( + &self, + fx: &mut FunctionCx<'a, 'tcx, Bx>, + bx: &mut Bx, + fn_abi: &'tcx FnAbi<'tcx, Ty<'tcx>>, + fn_ptr: Bx::Value, + llargs: &[Bx::Value], + destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>, + cleanup: Option, + copied_constant_arguments: &[PlaceRef<'tcx, ::Value>], + ) { + // If there is a cleanup block and the function we're calling can unwind, then + // do an invoke, otherwise do a call. + let fn_ty = bx.fn_decl_backend_type(&fn_abi); + + let unwind_block = if let Some(cleanup) = cleanup.filter(|_| fn_abi.can_unwind) { + Some(self.llblock(fx, cleanup)) + } else if fx.mir[self.bb].is_cleanup + && fn_abi.can_unwind + && !base::wants_msvc_seh(fx.cx.tcx().sess) + { + // Exception must not propagate out of the execution of a cleanup (doing so + // can cause undefined behaviour). We insert a double unwind guard for + // functions that can potentially unwind to protect against this. + // + // This is not necessary for SEH which does not use successive unwinding + // like Itanium EH. EH frames in SEH are different from normal function + // frames and SEH will abort automatically if an exception tries to + // propagate out from cleanup. + Some(fx.double_unwind_guard()) + } else { + None + }; + + if let Some(unwind_block) = unwind_block { + let ret_llbb = if let Some((_, target)) = destination { + fx.llbb(target) + } else { + fx.unreachable_block() + }; + let invokeret = + bx.invoke(fn_ty, fn_ptr, &llargs, ret_llbb, unwind_block, self.funclet(fx)); + bx.apply_attrs_callsite(&fn_abi, invokeret); + if fx.mir[self.bb].is_cleanup { + bx.do_not_inline(invokeret); + } + + if let Some((ret_dest, target)) = destination { + bx.switch_to_block(fx.llbb(target)); + fx.set_debug_loc(bx, self.terminator.source_info); + for tmp in copied_constant_arguments { + bx.lifetime_end(tmp.llval, tmp.layout.size); + } + fx.store_return(bx, ret_dest, &fn_abi.ret, invokeret); + } + } else { + let llret = bx.call(fn_ty, 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 { + for tmp in copied_constant_arguments { + bx.lifetime_end(tmp.llval, tmp.layout.size); + } + fx.store_return(bx, ret_dest, &fn_abi.ret, llret); + self.funclet_br(fx, bx, target); + } else { + bx.unreachable(); + } + } + } + + /// Generates inline assembly with optional `destination` and `cleanup`. + fn do_inlineasm>( + &self, + fx: &mut FunctionCx<'a, 'tcx, Bx>, + bx: &mut Bx, + template: &[InlineAsmTemplatePiece], + operands: &[InlineAsmOperandRef<'tcx, Bx>], + options: InlineAsmOptions, + line_spans: &[Span], + destination: Option, + cleanup: Option, + instance: Instance<'_>, + ) { + if let Some(cleanup) = cleanup { + let ret_llbb = if let Some(target) = destination { + fx.llbb(target) + } else { + fx.unreachable_block() + }; + + bx.codegen_inline_asm( + template, + &operands, + options, + line_spans, + instance, + Some((ret_llbb, self.llblock(fx, cleanup), self.funclet(fx))), + ); + } else { + bx.codegen_inline_asm(template, &operands, options, line_spans, instance, None); + + if let Some(target) = destination { + self.funclet_br(fx, bx, target); + } else { + bx.unreachable(); + } + } + } +} + +/// 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(&mut self, helper: TerminatorCodegenHelper<'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); + + 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); + } + } + + fn codegen_switchint_terminator( + &mut self, + helper: TerminatorCodegenHelper<'tcx>, + mut bx: Bx, + discr: &mir::Operand<'tcx>, + switch_ty: Ty<'tcx>, + targets: &SwitchTargets, + ) { + let discr = self.codegen_operand(&mut bx, &discr); + // `switch_ty` is redundant, sanity-check that. + assert_eq!(discr.layout.ty, switch_ty); + let mut target_iter = targets.iter(); + if target_iter.len() == 1 { + // If there are two targets (one conditional, one fallback), emit br instead of switch + let (test_value, target) = target_iter.next().unwrap(); + let lltrue = helper.llblock(self, target); + let llfalse = helper.llblock(self, targets.otherwise()); + if switch_ty == bx.tcx().types.bool { + // Don't generate trivial icmps when switching on bool + match test_value { + 0 => bx.cond_br(discr.immediate(), llfalse, lltrue), + 1 => bx.cond_br(discr.immediate(), lltrue, llfalse), + _ => bug!(), + } + } else { + let switch_llty = bx.immediate_backend_type(bx.layout_of(switch_ty)); + let llval = bx.const_uint_big(switch_llty, test_value); + let cmp = bx.icmp(IntPredicate::IntEQ, discr.immediate(), llval); + bx.cond_br(cmp, lltrue, llfalse); + } + } else { + bx.switch( + discr.immediate(), + helper.llblock(self, targets.otherwise()), + target_iter.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. + // We play it safe by using a well-defined `abort`, but we could go for immediate UB + // if that turns out to be helpful. + bx.abort(); + // `abort` does not terminate the block, so we still need to generate + // an `unreachable` terminator after it. + 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(bx.backend_type(op.layout), 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 ty = bx.cast_backend_type(&cast_ty); + let addr = bx.pointercast(llslot, bx.type_ptr_to(ty)); + bx.load(ty, addr, self.fn_abi.ret.layout.align.abi) + } + }; + bx.ret(llval); + } + + fn codegen_drop_terminator( + &mut self, + helper: TerminatorCodegenHelper<'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 = 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.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() { + // FIXME(eddyb) perhaps move some of this logic into + // `Instance::resolve_drop_in_place`? + ty::Dynamic(..) => { + let virtual_drop = Instance { + def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0), + substs: drop_fn.substs, + }; + let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty()); + let vtable = args[1]; + args = &args[..1]; + ( + meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE) + .get_fn(&mut bx, vtable, ty, &fn_abi), + fn_abi, + ) + } + _ => (bx.get_fn_addr(drop_fn), bx.fn_abi_of_instance(drop_fn, ty::List::empty())), + }; + helper.do_call( + self, + &mut bx, + fn_abi, + drop_fn, + args, + Some((ReturnDest::Nothing, target)), + unwind, + &[], + ); + } + + fn codegen_assert_terminator( + &mut self, + helper: TerminatorCodegenHelper<'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 AssertKind::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 = bx.append_sibling_block("panic"); + if expected { + bx.cond_br(cond, lltarget, panic_block); + } else { + bx.cond_br(cond, panic_block, lltarget); + } + + // After this point, bx is the block for the call to panic. + bx.switch_to_block(panic_block); + self.set_debug_loc(&mut bx, terminator.source_info); + + // Get the location information. + let location = self.get_caller_location(&mut bx, terminator.source_info).immediate(); + + // Put together the arguments to the panic entry point. + let (lang_item, args) = match msg { + AssertKind::BoundsCheck { ref len, ref index } => { + let len = self.codegen_operand(&mut bx, len).immediate(); + let index = self.codegen_operand(&mut bx, index).immediate(); + // It's `fn panic_bounds_check(index: usize, len: usize)`, + // and `#[track_caller]` adds an implicit third argument. + (LangItem::PanicBoundsCheck, vec![index, len, location]) + } + _ => { + let msg = bx.const_str(msg.description()); + // It's `pub fn panic(expr: &str)`, with the wide reference being passed + // as two arguments, and `#[track_caller]` adds an implicit third argument. + (LangItem::Panic, vec![msg.0, msg.1, location]) + } + }; + + let (fn_abi, llfn) = common::build_langcall(&bx, Some(span), lang_item); + + // Codegen the actual panic invoke/call. + helper.do_call(self, &mut bx, fn_abi, llfn, &args, None, cleanup, &[]); + } + + fn codegen_abort_terminator( + &mut self, + helper: TerminatorCodegenHelper<'tcx>, + mut bx: Bx, + terminator: &mir::Terminator<'tcx>, + ) { + let span = terminator.source_info.span; + self.set_debug_loc(&mut bx, terminator.source_info); + + // Obtain the panic entry point. + let (fn_abi, llfn) = common::build_langcall(&bx, Some(span), LangItem::PanicNoUnwind); + + // Codegen the actual panic invoke/call. + helper.do_call(self, &mut bx, fn_abi, llfn, &[], None, None, &[]); + } + + /// Returns `true` if this is indeed a panic intrinsic and codegen is done. + fn codegen_panic_intrinsic( + &mut self, + helper: &TerminatorCodegenHelper<'tcx>, + bx: &mut Bx, + intrinsic: Option, + instance: Option>, + source_info: mir::SourceInfo, + target: Option, + cleanup: Option, + ) -> bool { + // Emit a panic or a no-op for `assert_*` intrinsics. + // These are intrinsics that compile to panics so that we can get a message + // which mentions the offending type, even from a const context. + #[derive(Debug, PartialEq)] + enum AssertIntrinsic { + Inhabited, + ZeroValid, + UninitValid, + } + let panic_intrinsic = intrinsic.and_then(|i| match i { + sym::assert_inhabited => Some(AssertIntrinsic::Inhabited), + sym::assert_zero_valid => Some(AssertIntrinsic::ZeroValid), + sym::assert_uninit_valid => Some(AssertIntrinsic::UninitValid), + _ => None, + }); + if let Some(intrinsic) = panic_intrinsic { + use AssertIntrinsic::*; + + let ty = instance.unwrap().substs.type_at(0); + let layout = bx.layout_of(ty); + let do_panic = match intrinsic { + Inhabited => layout.abi.is_uninhabited(), + ZeroValid => !bx.tcx().permits_zero_init(layout), + UninitValid => !bx.tcx().permits_uninit_init(layout), + }; + if do_panic { + let msg_str = with_no_visible_paths!({ + with_no_trimmed_paths!({ + if layout.abi.is_uninhabited() { + // Use this error even for the other intrinsics as it is more precise. + format!("attempted to instantiate uninhabited type `{}`", ty) + } else if intrinsic == ZeroValid { + format!("attempted to zero-initialize type `{}`, which is invalid", ty) + } else { + format!( + "attempted to leave type `{}` uninitialized, which is invalid", + ty + ) + } + }) + }); + let msg = bx.const_str(&msg_str); + let location = self.get_caller_location(bx, source_info).immediate(); + + // Obtain the panic entry point. + let (fn_abi, llfn) = + common::build_langcall(bx, Some(source_info.span), LangItem::Panic); + + // Codegen the actual panic invoke/call. + helper.do_call( + self, + bx, + fn_abi, + llfn, + &[msg.0, msg.1, location], + target.as_ref().map(|bb| (ReturnDest::Nothing, *bb)), + cleanup, + &[], + ); + } else { + // a NOP + let target = target.unwrap(); + helper.funclet_br(self, bx, target) + } + true + } else { + false + } + } + + fn codegen_call_terminator( + &mut self, + helper: TerminatorCodegenHelper<'tcx>, + mut bx: Bx, + terminator: &mir::Terminator<'tcx>, + func: &mir::Operand<'tcx>, + args: &[mir::Operand<'tcx>], + destination: mir::Place<'tcx>, + target: Option, + cleanup: Option, + fn_span: Span, + ) { + let source_info = terminator.source_info; + let span = 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() + .unwrap() + .polymorphize(bx.tcx()), + ), + None, + ), + ty::FnPtr(_) => (None, Some(callee.immediate())), + _ => bug!("{} is not callable", callee.layout.ty), + }; + let def = instance.map(|i| i.def); + + if let Some(ty::InstanceDef::DropGlue(_, None)) = def { + // Empty drop glue; a no-op. + let target = target.unwrap(); + helper.funclet_br(self, &mut bx, target); + return; + } + + // FIXME(eddyb) avoid computing this if possible, when `instance` is + // available - right now `sig` is only needed for getting the `abi` + // and figuring out how many extra args were passed to a C-variadic `fn`. + let sig = callee.layout.ty.fn_sig(bx.tcx()); + 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)), + _ => None, + }; + + let extra_args = &args[sig.inputs().skip_binder().len()..]; + let extra_args = bx.tcx().mk_type_list(extra_args.iter().map(|op_arg| { + let op_ty = op_arg.ty(self.mir, bx.tcx()); + self.monomorphize(op_ty) + })); + + let fn_abi = match instance { + Some(instance) => bx.fn_abi_of_instance(instance, extra_args), + None => bx.fn_abi_of_fn_ptr(sig, extra_args), + }; + + if intrinsic == Some(sym::transmute) { + if let Some(target) = target { + self.codegen_transmute(&mut bx, &args[0], destination); + 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!(fn_abi.ret.layout.abi, abi::Abi::Uninhabited); + bx.unreachable(); + } + return; + } + + if self.codegen_panic_intrinsic( + &helper, + &mut bx, + intrinsic, + instance, + source_info, + target, + cleanup, + ) { + 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 target.is_some() { + let is_intrinsic = intrinsic.is_some(); + self.make_return_dest(&mut bx, destination, &fn_abi.ret, &mut llargs, is_intrinsic) + } else { + ReturnDest::Nothing + }; + + if intrinsic == Some(sym::caller_location) { + if let Some(target) = target { + let location = self + .get_caller_location(&mut bx, mir::SourceInfo { span: fn_span, ..source_info }); + + 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.funclet_br(self, &mut bx, target); + } + return; + } + + match intrinsic { + None | Some(sym::drop_in_place) => {} + Some(sym::copy_nonoverlapping) => unreachable!(), + Some(intrinsic) => { + 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.as_str().starts_with("simd_shuffle") { + if let mir::Operand::Constant(constant) = arg { + let c = self.eval_mir_constant(constant); + let (llval, ty) = self.simd_shuffle_indices( + &bx, + constant.span, + self.monomorphize(constant.ty()), + c, + ); + return OperandRef { + val: Immediate(llval), + layout: bx.layout_of(ty), + }; + } else { + span_bug!(span, "shuffle indices must be constant"); + } + } + + self.codegen_operand(&mut bx, arg) + }) + .collect(); + + Self::codegen_intrinsic_call( + &mut bx, + *instance.as_ref().unwrap(), + &fn_abi, + &args, + dest, + span, + ); + + if let ReturnDest::IndirectOperand(dst, _) = ret_dest { + self.store_return(&mut bx, ret_dest, &fn_abi.ret, dst.llval); + } + + if let Some(target) = 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) + }; + + let mut copied_constant_arguments = vec![]; + '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() + { + 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, + op.layout.ty, + &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, + op.layout.ty, + &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); + bx.lifetime_start(tmp.llval, tmp.layout.size); + op.val.store(&mut bx, tmp); + op.val = Ref(tmp.llval, None, tmp.align); + copied_constant_arguments.push(tmp); + } + _ => {} + } + + self.codegen_argument(&mut bx, op, &mut llargs, &fn_abi.args[i]); + } + let num_untupled = untuple.map(|tup| { + self.codegen_arguments_untupled( + &mut bx, + tup, + &mut llargs, + &fn_abi.args[first_args.len()..], + ) + }); + + let needs_location = + instance.map_or(false, |i| i.def.requires_caller_location(self.cx.tcx())); + if needs_location { + let mir_args = if let Some(num_untupled) = num_untupled { + first_args.len() + num_untupled + } else { + args.len() + }; + assert_eq!( + fn_abi.args.len(), + mir_args + 1, + "#[track_caller] fn's must have 1 more argument in their ABI than in their MIR: {:?} {:?} {:?}", + instance, + fn_span, + fn_abi, + ); + let location = + self.get_caller_location(&mut bx, mir::SourceInfo { span: fn_span, ..source_info }); + debug!( + "codegen_call_terminator({:?}): location={:?} (fn_span {:?})", + terminator, location, fn_span + ); + + let last_arg = fn_abi.args.last().unwrap(); + self.codegen_argument(&mut bx, location, &mut llargs, last_arg); + } + + let (is_indirect_call, fn_ptr) = match (llfn, instance) { + (Some(llfn), _) => (true, llfn), + (None, Some(instance)) => (false, bx.get_fn_addr(instance)), + _ => span_bug!(span, "no llfn for call"), + }; + + // For backends that support CFI using type membership (i.e., testing whether a given + // pointer is associated with a type identifier). + if bx.tcx().sess.is_sanitizer_cfi_enabled() && is_indirect_call { + // Emit type metadata and checks. + // FIXME(rcvalle): Add support for generalized identifiers. + // FIXME(rcvalle): Create distinct unnamed MDNodes for internal identifiers. + let typeid = typeid_for_fnabi(bx.tcx(), fn_abi); + let typeid_metadata = self.cx.typeid_metadata(typeid); + + // Test whether the function pointer is associated with the type identifier. + let cond = bx.type_test(fn_ptr, typeid_metadata); + let bb_pass = bx.append_sibling_block("type_test.pass"); + let bb_fail = bx.append_sibling_block("type_test.fail"); + bx.cond_br(cond, bb_pass, bb_fail); + + bx.switch_to_block(bb_pass); + helper.do_call( + self, + &mut bx, + fn_abi, + fn_ptr, + &llargs, + target.as_ref().map(|&target| (ret_dest, target)), + cleanup, + &copied_constant_arguments, + ); + + bx.switch_to_block(bb_fail); + bx.abort(); + bx.unreachable(); + + return; + } + + helper.do_call( + self, + &mut bx, + fn_abi, + fn_ptr, + &llargs, + target.as_ref().map(|&target| (ret_dest, target)), + cleanup, + &copied_constant_arguments, + ); + } + + fn codegen_asm_terminator( + &mut self, + helper: TerminatorCodegenHelper<'tcx>, + mut bx: Bx, + terminator: &mir::Terminator<'tcx>, + template: &[ast::InlineAsmTemplatePiece], + operands: &[mir::InlineAsmOperand<'tcx>], + options: ast::InlineAsmOptions, + line_spans: &[Span], + destination: Option, + cleanup: Option, + instance: Instance<'_>, + ) { + let span = terminator.source_info.span; + + let operands: Vec<_> = operands + .iter() + .map(|op| match *op { + mir::InlineAsmOperand::In { reg, ref value } => { + let value = self.codegen_operand(&mut bx, value); + InlineAsmOperandRef::In { reg, value } + } + mir::InlineAsmOperand::Out { reg, late, ref place } => { + let place = place.map(|place| self.codegen_place(&mut bx, place.as_ref())); + InlineAsmOperandRef::Out { reg, late, place } + } + mir::InlineAsmOperand::InOut { reg, late, ref in_value, ref out_place } => { + let in_value = self.codegen_operand(&mut bx, in_value); + let out_place = + out_place.map(|out_place| self.codegen_place(&mut bx, out_place.as_ref())); + InlineAsmOperandRef::InOut { reg, late, in_value, out_place } + } + mir::InlineAsmOperand::Const { ref value } => { + let const_value = self + .eval_mir_constant(value) + .unwrap_or_else(|_| span_bug!(span, "asm const cannot be resolved")); + let string = common::asm_const_to_str( + bx.tcx(), + span, + const_value, + bx.layout_of(value.ty()), + ); + InlineAsmOperandRef::Const { string } + } + mir::InlineAsmOperand::SymFn { ref value } => { + let literal = self.monomorphize(value.literal); + if let ty::FnDef(def_id, substs) = *literal.ty().kind() { + let instance = ty::Instance::resolve_for_fn_ptr( + bx.tcx(), + ty::ParamEnv::reveal_all(), + def_id, + substs, + ) + .unwrap(); + InlineAsmOperandRef::SymFn { instance } + } else { + span_bug!(span, "invalid type for asm sym (fn)"); + } + } + mir::InlineAsmOperand::SymStatic { def_id } => { + InlineAsmOperandRef::SymStatic { def_id } + } + }) + .collect(); + + helper.do_inlineasm( + self, + &mut bx, + template, + &operands, + options, + line_spans, + destination, + cleanup, + instance, + ); + } +} + +impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { + pub fn codegen_block(&mut self, bb: mir::BasicBlock) { + let llbb = self.llbb(bb); + let mut bx = Bx::build(self.cx, llbb); + let mir = self.mir; + let data = &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: &'tcx 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, 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 => { + self.codegen_abort_terminator(helper, bx, terminator); + } + + mir::TerminatorKind::Goto { target } => { + helper.funclet_br(self, &mut bx, target); + } + + mir::TerminatorKind::SwitchInt { ref discr, switch_ty, ref targets } => { + self.codegen_switchint_terminator(helper, bx, discr, switch_ty, targets); + } + + mir::TerminatorKind::Return => { + self.codegen_return_terminator(bx); + } + + mir::TerminatorKind::Unreachable => { + bx.unreachable(); + } + + mir::TerminatorKind::Drop { place, target, unwind } => { + self.codegen_drop_terminator(helper, bx, place, 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, + destination, + target, + cleanup, + from_hir_call: _, + fn_span, + } => { + self.codegen_call_terminator( + helper, + bx, + terminator, + func, + args, + destination, + target, + cleanup, + fn_span, + ); + } + mir::TerminatorKind::GeneratorDrop | mir::TerminatorKind::Yield { .. } => { + bug!("generator ops in codegen") + } + mir::TerminatorKind::FalseEdge { .. } | mir::TerminatorKind::FalseUnwind { .. } => { + bug!("borrowck false edges in codegen") + } + + mir::TerminatorKind::InlineAsm { + template, + ref operands, + options, + line_spans, + destination, + cleanup, + } => { + self.codegen_asm_terminator( + helper, + bx, + terminator, + template, + operands, + options, + line_spans, + destination, + cleanup, + self.instance, + ); + } + } + } + + 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 llty = bx.cast_backend_type(&ty); + let addr = bx.pointercast(llval, bx.type_ptr_to(llty)); + llval = bx.load(llty, 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(bx.backend_type(arg.layout), llval, align); + if let abi::Abi::Scalar(scalar) = arg.layout.abi { + if scalar.is_bool() { + bx.range_metadata(llval, WrappingRange { start: 0, end: 1 }); + } + } + // We store bools as `i8` so we need to truncate to `i1`. + llval = bx.to_immediate(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>>], + ) -> usize { + 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]); + } + } + tuple.layout.fields.count() + } + + fn get_caller_location( + &mut self, + bx: &mut Bx, + mut source_info: mir::SourceInfo, + ) -> OperandRef<'tcx, Bx::Value> { + let tcx = bx.tcx(); + + let mut span_to_caller_location = |span: Span| { + let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span); + let caller = tcx.sess.source_map().lookup_char_pos(topmost.lo()); + let const_loc = tcx.const_caller_location(( + Symbol::intern(&caller.file.name.prefer_remapped().to_string_lossy()), + caller.line as u32, + caller.col_display as u32 + 1, + )); + OperandRef::from_const(bx, const_loc, bx.tcx().caller_location_ty()) + }; + + // Walk up the `SourceScope`s, in case some of them are from MIR inlining. + // If so, the starting `source_info.span` is in the innermost inlined + // function, and will be replaced with outer callsite spans as long + // as the inlined functions were `#[track_caller]`. + loop { + let scope_data = &self.mir.source_scopes[source_info.scope]; + + if let Some((callee, callsite_span)) = scope_data.inlined { + // Stop inside the most nested non-`#[track_caller]` function, + // before ever reaching its caller (which is irrelevant). + if !callee.def.requires_caller_location(tcx) { + return span_to_caller_location(source_info.span); + } + source_info.span = callsite_span; + } + + // Skip past all of the parents with `inlined: None`. + match scope_data.inlined_parent_scope { + Some(parent) => source_info.scope = parent, + None => break, + } + } + + // No inlined `SourceScope`s, or all of them were `#[track_caller]`. + self.caller_location.unwrap_or_else(|| span_to_caller_location(source_info.span)) + } + + 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/cleanup pad wrapper around the given basic block. + // FIXME(eddyb) rename this to `eh_pad_for`. + fn landing_pad_for(&mut self, bb: mir::BasicBlock) -> Bx::BasicBlock { + if let Some(landing_pad) = self.landing_pads[bb] { + return landing_pad; + } + + let landing_pad = self.landing_pad_for_uncached(bb); + self.landing_pads[bb] = Some(landing_pad); + landing_pad + } + + // FIXME(eddyb) rename this to `eh_pad_for_uncached`. + fn landing_pad_for_uncached(&mut self, bb: mir::BasicBlock) -> Bx::BasicBlock { + let llbb = self.llbb(bb); + if base::wants_msvc_seh(self.cx.sess()) { + let funclet; + let ret_llbb; + match self.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 cs_bb = + Bx::append_block(self.cx, self.llfn, &format!("cs_funclet{:?}", bb)); + let cp_bb = + Bx::append_block(self.cx, self.llfn, &format!("cp_funclet{:?}", bb)); + ret_llbb = cs_bb; + + let mut cs_bx = Bx::build(self.cx, cs_bb); + let cs = cs_bx.catch_switch(None, None, &[cp_bb]); + + // 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 mut cp_bx = Bx::build(self.cx, cp_bb); + let null = cp_bx.const_null( + cp_bx.type_i8p_ext(cp_bx.cx().data_layout().instruction_address_space), + ); + let sixty_four = cp_bx.const_i32(64); + funclet = cp_bx.catch_pad(cs, &[null, sixty_four, null]); + cp_bx.br(llbb); + } + _ => { + let cleanup_bb = + Bx::append_block(self.cx, self.llfn, &format!("funclet_{:?}", bb)); + ret_llbb = cleanup_bb; + let mut cleanup_bx = Bx::build(self.cx, cleanup_bb); + funclet = cleanup_bx.cleanup_pad(None, &[]); + cleanup_bx.br(llbb); + } + } + self.funclets[bb] = Some(funclet); + ret_llbb + } else { + let bb = Bx::append_block(self.cx, self.llfn, "cleanup"); + let mut bx = Bx::build(self.cx, bb); + + let llpersonality = self.cx.eh_personality(); + let llretty = self.landing_pad_type(); + let lp = bx.cleanup_landing_pad(llretty, llpersonality); + + 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(llbb); + 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 llbb = Bx::append_block(self.cx, self.llfn, "unreachable"); + let mut bx = Bx::build(self.cx, llbb); + bx.unreachable(); + self.unreachable_block = Some(llbb); + llbb + }) + } + + fn double_unwind_guard(&mut self) -> Bx::BasicBlock { + self.double_unwind_guard.unwrap_or_else(|| { + assert!(!base::wants_msvc_seh(self.cx.sess())); + + let llbb = Bx::append_block(self.cx, self.llfn, "abort"); + let mut bx = Bx::build(self.cx, llbb); + self.set_debug_loc(&mut bx, mir::SourceInfo::outermost(self.mir.span)); + + let llpersonality = self.cx.eh_personality(); + let llretty = self.landing_pad_type(); + bx.cleanup_landing_pad(llretty, llpersonality); + + let (fn_abi, fn_ptr) = common::build_langcall(&bx, None, LangItem::PanicNoUnwind); + let fn_ty = bx.fn_decl_backend_type(&fn_abi); + + let llret = bx.call(fn_ty, fn_ptr, &[], None); + bx.apply_attrs_callsite(&fn_abi, llret); + bx.do_not_inline(llret); + + bx.unreachable(); + + self.double_unwind_guard = Some(llbb); + llbb + }) + } + + /// Get the backend `BasicBlock` for a MIR `BasicBlock`, either already + /// cached in `self.cached_llbbs`, or created on demand (and cached). + // FIXME(eddyb) rename `llbb` and other `ll`-prefixed things to use a + // more backend-agnostic prefix such as `cg` (i.e. this would be `cgbb`). + pub fn llbb(&mut self, bb: mir::BasicBlock) -> Bx::BasicBlock { + self.cached_llbbs[bb].unwrap_or_else(|| { + // FIXME(eddyb) only name the block if `fewer_names` is `false`. + let llbb = Bx::append_block(self.cx, self.llfn, &format!("{:?}", bb)); + self.cached_llbbs[bb] = Some(llbb); + llbb + }) + } + + fn make_return_dest( + &mut self, + bx: &mut Bx, + dest: mir::Place<'tcx>, + fn_ret: &ArgAbi<'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 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 { local: dest.local, 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)); + self.debug_introduce_local(bx, index); + } + 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); + + // Special-case transmutes between scalars as simple bitcasts. + match (src.layout.abi, dst.layout.abi) { + (abi::Abi::Scalar(src_scalar), abi::Abi::Scalar(dst_scalar)) => { + // HACK(eddyb) LLVM doesn't like `bitcast`s between pointers and non-pointers. + if (src_scalar.primitive() == abi::Pointer) + == (dst_scalar.primitive() == abi::Pointer) + { + assert_eq!(src.layout.size, dst.layout.size); + + // NOTE(eddyb) the `from_immediate` and `to_immediate_scalar` + // conversions allow handling `bool`s the same as `u8`s. + let src = bx.from_immediate(src.immediate()); + let src_as_dst = bx.bitcast(src, bx.backend_type(dst.layout)); + Immediate(bx.to_immediate_scalar(src_as_dst, dst_scalar)).store(bx, dst); + return; + } + } + _ => {} + } + + 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)); + self.debug_introduce_local(bx, index); + } + 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)); + self.debug_introduce_local(bx, index); + } + } + } +} + +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), +} -- cgit v1.2.3