| use std::cmp; |
| |
| use rustc_ast as ast; |
| use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece}; |
| use rustc_hir::lang_items::LangItem; |
| use rustc_middle::mir::{ |
| self, AssertKind, BasicBlock, InlineAsmMacro, SwitchTargets, UnwindTerminateReason, |
| }; |
| use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, ValidityRequirement}; |
| use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths}; |
| use rustc_middle::ty::{self, Instance, Ty}; |
| use rustc_middle::{bug, span_bug}; |
| use rustc_session::config::OptLevel; |
| use rustc_span::source_map::Spanned; |
| use rustc_span::{Span, sym}; |
| use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode, Reg}; |
| use rustc_target::abi::{self, HasDataLayout, WrappingRange}; |
| use rustc_target::spec::abi::Abi; |
| use tracing::{debug, info}; |
| |
| use super::operand::OperandRef; |
| use super::operand::OperandValue::{Immediate, Pair, Ref, ZeroSized}; |
| use super::place::{PlaceRef, PlaceValue}; |
| use super::{CachedLlbb, FunctionCx, LocalRef}; |
| use crate::base::{self, is_call_from_compiler_builtins_to_upstream_monomorphization}; |
| use crate::common::{self, IntPredicate}; |
| use crate::errors::CompilerBuiltinsCannotCall; |
| use crate::traits::*; |
| use crate::{MemFlags, meth}; |
| |
| // Indicates if we are in the middle of merging a BB's successor into it. This |
| // can happen when BB jumps directly to its successor and the successor has no |
| // other predecessors. |
| #[derive(Debug, PartialEq)] |
| enum MergingSucc { |
| False, |
| True, |
| } |
| |
| /// 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>, |
| } |
| |
| 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 cleanup_kinds = fx.cleanup_kinds.as_ref()?; |
| let funclet_bb = cleanup_kinds[self.bb].funclet_bb(self.bb)?; |
| // 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"), |
| ) |
| } |
| |
| /// Get a basic block (creating it if necessary), possibly with cleanup |
| /// stuff in it or next to it. |
| fn llbb_with_cleanup<Bx: BuilderMethods<'a, 'tcx>>( |
| &self, |
| fx: &mut FunctionCx<'a, 'tcx, Bx>, |
| target: mir::BasicBlock, |
| ) -> Bx::BasicBlock { |
| let (needs_landing_pad, is_cleanupret) = self.llbb_characteristics(fx, target); |
| let mut lltarget = fx.llbb(target); |
| if needs_landing_pad { |
| lltarget = fx.landing_pad_for(target); |
| } |
| if is_cleanupret { |
| // Cross-funclet jump - need a trampoline |
| assert!(base::wants_new_eh_instructions(fx.cx.tcx().sess)); |
| debug!("llbb_with_cleanup: creating cleanup trampoline for {:?}", target); |
| let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target); |
| let trampoline_llbb = Bx::append_block(fx.cx, fx.llfn, name); |
| let mut trampoline_bx = Bx::build(fx.cx, trampoline_llbb); |
| trampoline_bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget)); |
| trampoline_llbb |
| } else { |
| lltarget |
| } |
| } |
| |
| fn llbb_characteristics<Bx: BuilderMethods<'a, 'tcx>>( |
| &self, |
| fx: &mut FunctionCx<'a, 'tcx, Bx>, |
| target: mir::BasicBlock, |
| ) -> (bool, bool) { |
| if let Some(ref cleanup_kinds) = fx.cleanup_kinds { |
| let funclet_bb = cleanup_kinds[self.bb].funclet_bb(self.bb); |
| let target_funclet = cleanup_kinds[target].funclet_bb(target); |
| let (needs_landing_pad, is_cleanupret) = match (funclet_bb, target_funclet) { |
| (None, None) => (false, false), |
| (None, Some(_)) => (true, false), |
| (Some(f), Some(t_f)) => (f != t_f, f != t_f), |
| (Some(_), None) => { |
| let span = self.terminator.source_info.span; |
| span_bug!(span, "{:?} - jump out of cleanup?", self.terminator); |
| } |
| }; |
| (needs_landing_pad, is_cleanupret) |
| } else { |
| let needs_landing_pad = !fx.mir[self.bb].is_cleanup && fx.mir[target].is_cleanup; |
| let is_cleanupret = false; |
| (needs_landing_pad, is_cleanupret) |
| } |
| } |
| |
| fn funclet_br<Bx: BuilderMethods<'a, 'tcx>>( |
| &self, |
| fx: &mut FunctionCx<'a, 'tcx, Bx>, |
| bx: &mut Bx, |
| target: mir::BasicBlock, |
| mergeable_succ: bool, |
| ) -> MergingSucc { |
| let (needs_landing_pad, is_cleanupret) = self.llbb_characteristics(fx, target); |
| if mergeable_succ && !needs_landing_pad && !is_cleanupret { |
| // We can merge the successor into this bb, so no need for a `br`. |
| MergingSucc::True |
| } else { |
| let mut lltarget = fx.llbb(target); |
| if needs_landing_pad { |
| lltarget = fx.landing_pad_for(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); |
| } |
| MergingSucc::False |
| } |
| } |
| |
| /// Call `fn_ptr` of `fn_abi` with the arguments `llargs`, the optional |
| /// return destination `destination` and the unwind action `unwind`. |
| fn do_call<Bx: BuilderMethods<'a, 'tcx>>( |
| &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)>, |
| mut unwind: mir::UnwindAction, |
| copied_constant_arguments: &[PlaceRef<'tcx, <Bx as BackendTypes>::Value>], |
| instance: Option<Instance<'tcx>>, |
| mergeable_succ: bool, |
| ) -> MergingSucc { |
| let tcx = bx.tcx(); |
| if let Some(instance) = instance { |
| if is_call_from_compiler_builtins_to_upstream_monomorphization(tcx, instance) { |
| if destination.is_some() { |
| let caller = with_no_trimmed_paths!(tcx.def_path_str(fx.instance.def_id())); |
| let callee = with_no_trimmed_paths!(tcx.def_path_str(instance.def_id())); |
| tcx.dcx().emit_err(CompilerBuiltinsCannotCall { caller, callee }); |
| } else { |
| info!( |
| "compiler_builtins call to diverging function {:?} replaced with abort", |
| instance.def_id() |
| ); |
| bx.abort(); |
| bx.unreachable(); |
| return MergingSucc::False; |
| } |
| } |
| } |
| |
| // 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 fn_attrs = if bx.tcx().def_kind(fx.instance.def_id()).has_codegen_attrs() { |
| Some(bx.tcx().codegen_fn_attrs(fx.instance.def_id())) |
| } else { |
| None |
| }; |
| |
| if !fn_abi.can_unwind { |
| unwind = mir::UnwindAction::Unreachable; |
| } |
| |
| let unwind_block = match unwind { |
| mir::UnwindAction::Cleanup(cleanup) => Some(self.llbb_with_cleanup(fx, cleanup)), |
| mir::UnwindAction::Continue => None, |
| mir::UnwindAction::Unreachable => None, |
| mir::UnwindAction::Terminate(reason) => { |
| if fx.mir[self.bb].is_cleanup && base::wants_new_eh_instructions(fx.cx.tcx().sess) { |
| // MSVC SEH will abort automatically if an exception tries to |
| // propagate out from cleanup. |
| |
| // FIXME(@mirkootter): For wasm, we currently do not support terminate during |
| // cleanup, because this requires a few more changes: The current code |
| // caches the `terminate_block` for each function; funclet based code - however - |
| // requires a different terminate_block for each funclet |
| // Until this is implemented, we just do not unwind inside cleanup blocks |
| |
| None |
| } else { |
| Some(fx.terminate_block(reason)) |
| } |
| } |
| }; |
| |
| 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_attrs, |
| Some(fn_abi), |
| fn_ptr, |
| llargs, |
| ret_llbb, |
| unwind_block, |
| self.funclet(fx), |
| instance, |
| ); |
| if fx.mir[self.bb].is_cleanup { |
| bx.apply_attrs_to_cleanup_callsite(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.val.llval, tmp.layout.size); |
| } |
| fx.store_return(bx, ret_dest, &fn_abi.ret, invokeret); |
| } |
| MergingSucc::False |
| } else { |
| let llret = |
| bx.call(fn_ty, fn_attrs, Some(fn_abi), fn_ptr, llargs, self.funclet(fx), instance); |
| if fx.mir[self.bb].is_cleanup { |
| bx.apply_attrs_to_cleanup_callsite(llret); |
| } |
| |
| if let Some((ret_dest, target)) = destination { |
| for tmp in copied_constant_arguments { |
| bx.lifetime_end(tmp.val.llval, tmp.layout.size); |
| } |
| fx.store_return(bx, ret_dest, &fn_abi.ret, llret); |
| self.funclet_br(fx, bx, target, mergeable_succ) |
| } else { |
| bx.unreachable(); |
| MergingSucc::False |
| } |
| } |
| } |
| |
| /// Generates inline assembly with optional `destination` and `unwind`. |
| fn do_inlineasm<Bx: BuilderMethods<'a, 'tcx>>( |
| &self, |
| fx: &mut FunctionCx<'a, 'tcx, Bx>, |
| bx: &mut Bx, |
| template: &[InlineAsmTemplatePiece], |
| operands: &[InlineAsmOperandRef<'tcx, Bx>], |
| options: InlineAsmOptions, |
| line_spans: &[Span], |
| destination: Option<mir::BasicBlock>, |
| unwind: mir::UnwindAction, |
| instance: Instance<'_>, |
| mergeable_succ: bool, |
| ) -> MergingSucc { |
| let unwind_target = match unwind { |
| mir::UnwindAction::Cleanup(cleanup) => Some(self.llbb_with_cleanup(fx, cleanup)), |
| mir::UnwindAction::Terminate(reason) => Some(fx.terminate_block(reason)), |
| mir::UnwindAction::Continue => None, |
| mir::UnwindAction::Unreachable => None, |
| }; |
| |
| if operands.iter().any(|x| matches!(x, InlineAsmOperandRef::Label { .. })) { |
| assert!(unwind_target.is_none()); |
| 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), |
| None, |
| ); |
| MergingSucc::False |
| } else if let Some(cleanup) = unwind_target { |
| 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), |
| Some((cleanup, self.funclet(fx))), |
| ); |
| MergingSucc::False |
| } else { |
| bx.codegen_inline_asm(template, operands, options, line_spans, instance, None, None); |
| |
| if let Some(target) = destination { |
| self.funclet_br(fx, bx, target, mergeable_succ) |
| } else { |
| bx.unreachable(); |
| MergingSucc::False |
| } |
| } |
| } |
| } |
| |
| /// 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>, bx: &mut Bx) { |
| if let Some(funclet) = helper.funclet(self) { |
| bx.cleanup_ret(funclet, None); |
| } else { |
| let slot = self.get_personality_slot(bx); |
| let exn0 = slot.project_field(bx, 0); |
| let exn0 = bx.load_operand(exn0).immediate(); |
| let exn1 = slot.project_field(bx, 1); |
| let exn1 = bx.load_operand(exn1).immediate(); |
| slot.storage_dead(bx); |
| |
| bx.resume(exn0, exn1); |
| } |
| } |
| |
| fn codegen_switchint_terminator( |
| &mut self, |
| helper: TerminatorCodegenHelper<'tcx>, |
| bx: &mut Bx, |
| discr: &mir::Operand<'tcx>, |
| targets: &SwitchTargets, |
| ) { |
| let discr = self.codegen_operand(bx, discr); |
| let discr_value = discr.immediate(); |
| let switch_ty = discr.layout.ty; |
| // If our discriminant is a constant we can branch directly |
| if let Some(const_discr) = bx.const_to_opt_u128(discr_value, false) { |
| let target = targets.target_for_value(const_discr); |
| bx.br(helper.llbb_with_cleanup(self, target)); |
| return; |
| }; |
| |
| 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.llbb_with_cleanup(self, target); |
| let llfalse = helper.llbb_with_cleanup(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_value, llfalse, lltrue), |
| 1 => bx.cond_br(discr_value, 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_value, llval); |
| bx.cond_br(cmp, lltrue, llfalse); |
| } |
| } else if self.cx.sess().opts.optimize == OptLevel::No |
| && target_iter.len() == 2 |
| && self.mir[targets.otherwise()].is_empty_unreachable() |
| { |
| // In unoptimized builds, if there are two normal targets and the `otherwise` target is |
| // an unreachable BB, emit `br` instead of `switch`. This leaves behind the unreachable |
| // BB, which will usually (but not always) be dead code. |
| // |
| // Why only in unoptimized builds? |
| // - In unoptimized builds LLVM uses FastISel which does not support switches, so it |
| // must fall back to the slower SelectionDAG isel. Therefore, using `br` gives |
| // significant compile time speedups for unoptimized builds. |
| // - In optimized builds the above doesn't hold, and using `br` sometimes results in |
| // worse generated code because LLVM can no longer tell that the value being switched |
| // on can only have two values, e.g. 0 and 1. |
| // |
| let (test_value1, target1) = target_iter.next().unwrap(); |
| let (_test_value2, target2) = target_iter.next().unwrap(); |
| let ll1 = helper.llbb_with_cleanup(self, target1); |
| let ll2 = helper.llbb_with_cleanup(self, target2); |
| let switch_llty = bx.immediate_backend_type(bx.layout_of(switch_ty)); |
| let llval = bx.const_uint_big(switch_llty, test_value1); |
| let cmp = bx.icmp(IntPredicate::IntEQ, discr_value, llval); |
| bx.cond_br(cmp, ll1, ll2); |
| } else { |
| bx.switch( |
| discr_value, |
| helper.llbb_with_cleanup(self, targets.otherwise()), |
| target_iter.map(|(value, target)| (value, helper.llbb_with_cleanup(self, target))), |
| ); |
| } |
| } |
| |
| fn codegen_return_terminator(&mut self, bx: &mut 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::from_usize(1 + va_list_arg_idx)] { |
| LocalRef::Place(va_list) => { |
| bx.va_end(va_list.val.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(bx, mir::Place::return_place().as_ref()); |
| if let Ref(place_val) = op.val { |
| bx.load_from_place(bx.backend_type(op.layout), place_val) |
| } else { |
| op.immediate_or_packed_pair(bx) |
| } |
| } |
| |
| PassMode::Cast { cast: cast_ty, pad_i32: _ } => { |
| let op = match self.locals[mir::RETURN_PLACE] { |
| LocalRef::Operand(op) => op, |
| LocalRef::PendingOperand => bug!("use of return before def"), |
| LocalRef::Place(cg_place) => { |
| OperandRef { val: Ref(cg_place.val), layout: cg_place.layout } |
| } |
| LocalRef::UnsizedPlace(_) => bug!("return type must be sized"), |
| }; |
| let llslot = match op.val { |
| Immediate(_) | Pair(..) => { |
| let scratch = PlaceRef::alloca(bx, self.fn_abi.ret.layout); |
| op.val.store(bx, scratch); |
| scratch.val.llval |
| } |
| Ref(place_val) => { |
| assert_eq!( |
| place_val.align, op.layout.align.abi, |
| "return place is unaligned!" |
| ); |
| place_val.llval |
| } |
| ZeroSized => bug!("ZST return value shouldn't be in PassMode::Cast"), |
| }; |
| let ty = bx.cast_backend_type(cast_ty); |
| bx.load(ty, llslot, self.fn_abi.ret.layout.align.abi) |
| } |
| }; |
| bx.ret(llval); |
| } |
| |
| #[tracing::instrument(level = "trace", skip(self, helper, bx))] |
| fn codegen_drop_terminator( |
| &mut self, |
| helper: TerminatorCodegenHelper<'tcx>, |
| bx: &mut Bx, |
| source_info: &mir::SourceInfo, |
| location: mir::Place<'tcx>, |
| target: mir::BasicBlock, |
| unwind: mir::UnwindAction, |
| mergeable_succ: bool, |
| ) -> MergingSucc { |
| 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::InstanceKind::DropGlue(_, None) = drop_fn.def { |
| // we don't actually need to drop anything. |
| return helper.funclet_br(self, bx, target, mergeable_succ); |
| } |
| |
| let place = self.codegen_place(bx, location.as_ref()); |
| let (args1, args2); |
| let mut args = if let Some(llextra) = place.val.llextra { |
| args2 = [place.val.llval, llextra]; |
| &args2[..] |
| } else { |
| args1 = [place.val.llval]; |
| &args1[..] |
| }; |
| let (maybe_null, drop_fn, fn_abi, drop_instance) = match ty.kind() { |
| // FIXME(eddyb) perhaps move some of this logic into |
| // `Instance::resolve_drop_in_place`? |
| ty::Dynamic(_, _, ty::Dyn) => { |
| // IN THIS ARM, WE HAVE: |
| // ty = *mut (dyn Trait) |
| // which is: exists<T> ( *mut T, Vtable<T: Trait> ) |
| // args[0] args[1] |
| // |
| // args = ( Data, Vtable ) |
| // | |
| // v |
| // /-------\ |
| // | ... | |
| // \-------/ |
| // |
| let virtual_drop = Instance { |
| def: ty::InstanceKind::Virtual(drop_fn.def_id(), 0), // idx 0: the drop function |
| args: drop_fn.args, |
| }; |
| debug!("ty = {:?}", ty); |
| debug!("drop_fn = {:?}", drop_fn); |
| debug!("args = {:?}", args); |
| let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty()); |
| let vtable = args[1]; |
| // Truncate vtable off of args list |
| args = &args[..1]; |
| ( |
| true, |
| meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE) |
| .get_optional_fn(bx, vtable, ty, fn_abi), |
| fn_abi, |
| virtual_drop, |
| ) |
| } |
| ty::Dynamic(_, _, ty::DynStar) => { |
| // IN THIS ARM, WE HAVE: |
| // ty = *mut (dyn* Trait) |
| // which is: *mut exists<T: sizeof(T) == sizeof(usize)> (T, Vtable<T: Trait>) |
| // |
| // args = [ * ] |
| // | |
| // v |
| // ( Data, Vtable ) |
| // | |
| // v |
| // /-------\ |
| // | ... | |
| // \-------/ |
| // |
| // |
| // WE CAN CONVERT THIS INTO THE ABOVE LOGIC BY DOING |
| // |
| // data = &(*args[0]).0 // gives a pointer to Data above (really the same pointer) |
| // vtable = (*args[0]).1 // loads the vtable out |
| // (data, vtable) // an equivalent Rust `*mut dyn Trait` |
| // |
| // SO THEN WE CAN USE THE ABOVE CODE. |
| let virtual_drop = Instance { |
| def: ty::InstanceKind::Virtual(drop_fn.def_id(), 0), // idx 0: the drop function |
| args: drop_fn.args, |
| }; |
| debug!("ty = {:?}", ty); |
| debug!("drop_fn = {:?}", drop_fn); |
| debug!("args = {:?}", args); |
| let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty()); |
| let meta_ptr = place.project_field(bx, 1); |
| let meta = bx.load_operand(meta_ptr); |
| // Truncate vtable off of args list |
| args = &args[..1]; |
| debug!("args' = {:?}", args); |
| ( |
| true, |
| meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE) |
| .get_optional_fn(bx, meta.immediate(), ty, fn_abi), |
| fn_abi, |
| virtual_drop, |
| ) |
| } |
| _ => ( |
| false, |
| bx.get_fn_addr(drop_fn), |
| bx.fn_abi_of_instance(drop_fn, ty::List::empty()), |
| drop_fn, |
| ), |
| }; |
| |
| // We generate a null check for the drop_fn. This saves a bunch of relocations being |
| // generated for no-op drops. |
| if maybe_null { |
| let is_not_null = bx.append_sibling_block("is_not_null"); |
| let llty = bx.fn_ptr_backend_type(fn_abi); |
| let null = bx.const_null(llty); |
| let non_null = |
| bx.icmp(base::bin_op_to_icmp_predicate(mir::BinOp::Ne, false), drop_fn, null); |
| bx.cond_br(non_null, is_not_null, helper.llbb_with_cleanup(self, target)); |
| bx.switch_to_block(is_not_null); |
| self.set_debug_loc(bx, *source_info); |
| } |
| |
| helper.do_call( |
| self, |
| bx, |
| fn_abi, |
| drop_fn, |
| args, |
| Some((ReturnDest::Nothing, target)), |
| unwind, |
| &[], |
| Some(drop_instance), |
| !maybe_null && mergeable_succ, |
| ) |
| } |
| |
| fn codegen_assert_terminator( |
| &mut self, |
| helper: TerminatorCodegenHelper<'tcx>, |
| bx: &mut Bx, |
| terminator: &mir::Terminator<'tcx>, |
| cond: &mir::Operand<'tcx>, |
| expected: bool, |
| msg: &mir::AssertMessage<'tcx>, |
| target: mir::BasicBlock, |
| unwind: mir::UnwindAction, |
| mergeable_succ: bool, |
| ) -> MergingSucc { |
| let span = terminator.source_info.span; |
| let cond = self.codegen_operand(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. |
| if !bx.sess().overflow_checks() && msg.is_optional_overflow_check() { |
| const_cond = Some(expected); |
| } |
| |
| // Don't codegen the panic block if success if known. |
| if const_cond == Some(expected) { |
| return helper.funclet_br(self, bx, target, mergeable_succ); |
| } |
| |
| // Because we're branching to a panic block (either a `#[cold]` one |
| // or an inlined abort), there's no need to `expect` it. |
| |
| // Create the failure block and the conditional branch to it. |
| let lltarget = helper.llbb_with_cleanup(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(bx, terminator.source_info); |
| |
| // Get the location information. |
| let location = self.get_caller_location(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(bx, len).immediate(); |
| let index = self.codegen_operand(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]) |
| } |
| AssertKind::MisalignedPointerDereference { ref required, ref found } => { |
| let required = self.codegen_operand(bx, required).immediate(); |
| let found = self.codegen_operand(bx, found).immediate(); |
| // It's `fn panic_misaligned_pointer_dereference(required: usize, found: usize)`, |
| // and `#[track_caller]` adds an implicit third argument. |
| (LangItem::PanicMisalignedPointerDereference, vec![required, found, location]) |
| } |
| _ => { |
| // It's `pub fn panic_...()` and `#[track_caller]` adds an implicit argument. |
| (msg.panic_function(), vec![location]) |
| } |
| }; |
| |
| let (fn_abi, llfn, instance) = common::build_langcall(bx, Some(span), lang_item); |
| |
| // Codegen the actual panic invoke/call. |
| let merging_succ = |
| helper.do_call(self, bx, fn_abi, llfn, &args, None, unwind, &[], Some(instance), false); |
| assert_eq!(merging_succ, MergingSucc::False); |
| MergingSucc::False |
| } |
| |
| fn codegen_terminate_terminator( |
| &mut self, |
| helper: TerminatorCodegenHelper<'tcx>, |
| bx: &mut Bx, |
| terminator: &mir::Terminator<'tcx>, |
| reason: UnwindTerminateReason, |
| ) { |
| let span = terminator.source_info.span; |
| self.set_debug_loc(bx, terminator.source_info); |
| |
| // Obtain the panic entry point. |
| let (fn_abi, llfn, instance) = common::build_langcall(bx, Some(span), reason.lang_item()); |
| |
| // Codegen the actual panic invoke/call. |
| let merging_succ = helper.do_call( |
| self, |
| bx, |
| fn_abi, |
| llfn, |
| &[], |
| None, |
| mir::UnwindAction::Unreachable, |
| &[], |
| Some(instance), |
| false, |
| ); |
| assert_eq!(merging_succ, MergingSucc::False); |
| } |
| |
| /// Returns `Some` if this is indeed a panic intrinsic and codegen is done. |
| fn codegen_panic_intrinsic( |
| &mut self, |
| helper: &TerminatorCodegenHelper<'tcx>, |
| bx: &mut Bx, |
| intrinsic: ty::IntrinsicDef, |
| instance: Option<Instance<'tcx>>, |
| source_info: mir::SourceInfo, |
| target: Option<mir::BasicBlock>, |
| unwind: mir::UnwindAction, |
| mergeable_succ: bool, |
| ) -> Option<MergingSucc> { |
| // 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. |
| if let Some(requirement) = ValidityRequirement::from_intrinsic(intrinsic.name) { |
| let ty = instance.unwrap().args.type_at(0); |
| |
| let do_panic = !bx |
| .tcx() |
| .check_validity_requirement((requirement, bx.param_env().and(ty))) |
| .expect("expect to have layout during codegen"); |
| |
| let layout = bx.layout_of(ty); |
| |
| Some(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 requirement == ValidityRequirement::Zero { |
| format!("attempted to zero-initialize type `{ty}`, which is invalid") |
| } else { |
| format!( |
| "attempted to leave type `{ty}` uninitialized, which is invalid" |
| ) |
| } |
| }) |
| }); |
| let msg = bx.const_str(&msg_str); |
| |
| // Obtain the panic entry point. |
| let (fn_abi, llfn, instance) = |
| common::build_langcall(bx, Some(source_info.span), LangItem::PanicNounwind); |
| |
| // Codegen the actual panic invoke/call. |
| helper.do_call( |
| self, |
| bx, |
| fn_abi, |
| llfn, |
| &[msg.0, msg.1], |
| target.as_ref().map(|bb| (ReturnDest::Nothing, *bb)), |
| unwind, |
| &[], |
| Some(instance), |
| mergeable_succ, |
| ) |
| } else { |
| // a NOP |
| let target = target.unwrap(); |
| helper.funclet_br(self, bx, target, mergeable_succ) |
| }) |
| } else { |
| None |
| } |
| } |
| |
| fn codegen_call_terminator( |
| &mut self, |
| helper: TerminatorCodegenHelper<'tcx>, |
| bx: &mut Bx, |
| terminator: &mir::Terminator<'tcx>, |
| func: &mir::Operand<'tcx>, |
| args: &[Spanned<mir::Operand<'tcx>>], |
| destination: mir::Place<'tcx>, |
| target: Option<mir::BasicBlock>, |
| unwind: mir::UnwindAction, |
| fn_span: Span, |
| mergeable_succ: bool, |
| ) -> MergingSucc { |
| 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(bx, func); |
| |
| let (instance, mut llfn) = match *callee.layout.ty.kind() { |
| ty::FnDef(def_id, args) => ( |
| Some( |
| ty::Instance::expect_resolve( |
| bx.tcx(), |
| ty::ParamEnv::reveal_all(), |
| def_id, |
| args, |
| fn_span, |
| ) |
| .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::InstanceKind::DropGlue(_, None) | ty::InstanceKind::AsyncDropGlueCtorShim(_, None), |
| ) = def |
| { |
| // Empty drop glue; a no-op. |
| let target = target.unwrap(); |
| return helper.funclet_br(self, bx, target, mergeable_succ); |
| } |
| |
| // 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(); |
| |
| let extra_args = &args[sig.inputs().skip_binder().len()..]; |
| let extra_args = bx.tcx().mk_type_list_from_iter(extra_args.iter().map(|op_arg| { |
| let op_ty = op_arg.node.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), |
| }; |
| |
| // 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 instance = match def { |
| Some(ty::InstanceKind::Intrinsic(def_id)) => { |
| let intrinsic = bx.tcx().intrinsic(def_id).unwrap(); |
| if let Some(merging_succ) = self.codegen_panic_intrinsic( |
| &helper, |
| bx, |
| intrinsic, |
| instance, |
| source_info, |
| target, |
| unwind, |
| mergeable_succ, |
| ) { |
| return merging_succ; |
| } |
| |
| let mut llargs = Vec::with_capacity(1); |
| let ret_dest = self.make_return_dest( |
| bx, |
| destination, |
| &fn_abi.ret, |
| &mut llargs, |
| Some(intrinsic), |
| target, |
| ); |
| let dest = match ret_dest { |
| _ if fn_abi.ret.is_indirect() => llargs[0], |
| ReturnDest::Nothing => bx.const_undef(bx.type_ptr()), |
| ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) => dst.val.llval, |
| ReturnDest::DirectOperand(_) => { |
| bug!("Cannot use direct operand with an intrinsic call") |
| } |
| }; |
| |
| let args: Vec<_> = |
| args.iter().map(|arg| self.codegen_operand(bx, &arg.node)).collect(); |
| |
| if matches!(intrinsic, ty::IntrinsicDef { name: sym::caller_location, .. }) { |
| let location = self |
| .get_caller_location(bx, mir::SourceInfo { span: fn_span, ..source_info }); |
| |
| assert_eq!(llargs, []); |
| if let ReturnDest::IndirectOperand(tmp, _) = ret_dest { |
| location.val.store(bx, tmp); |
| } |
| self.store_return(bx, ret_dest, &fn_abi.ret, location.immediate()); |
| return helper.funclet_br(self, bx, target.unwrap(), mergeable_succ); |
| } |
| |
| let instance = *instance.as_ref().unwrap(); |
| match Self::codegen_intrinsic_call(bx, instance, fn_abi, &args, dest, span) { |
| Ok(()) => { |
| if let ReturnDest::IndirectOperand(dst, _) = ret_dest { |
| self.store_return(bx, ret_dest, &fn_abi.ret, dst.val.llval); |
| } |
| |
| return if let Some(target) = target { |
| helper.funclet_br(self, bx, target, mergeable_succ) |
| } else { |
| bx.unreachable(); |
| MergingSucc::False |
| }; |
| } |
| Err(instance) => { |
| if intrinsic.must_be_overridden { |
| span_bug!( |
| span, |
| "intrinsic {} must be overridden by codegen backend, but isn't", |
| intrinsic.name, |
| ); |
| } |
| Some(instance) |
| } |
| } |
| } |
| _ => instance, |
| }; |
| |
| let mut llargs = Vec::with_capacity(arg_count); |
| let destination = target.as_ref().map(|&target| { |
| ( |
| self.make_return_dest( |
| bx, |
| destination, |
| &fn_abi.ret, |
| &mut llargs, |
| None, |
| Some(target), |
| ), |
| target, |
| ) |
| }); |
| |
| // 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(bx, &arg.node); |
| |
| if let (0, Some(ty::InstanceKind::Virtual(_, idx))) = (i, def) { |
| match op.val { |
| Pair(data_ptr, meta) => { |
| // In the case of Rc<Self>, we need to explicitly pass a |
| // *mut RcInner<Self> 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 RcInner<Self>`, we just keep unwrapping newtypes until |
| // we get a value of a built-in pointer type. |
| // |
| // This is also relevant for `Pin<&mut Self>`, where we need to peel the |
| // `Pin`. |
| while !op.layout.ty.is_unsafe_ptr() && !op.layout.ty.is_ref() { |
| let (idx, _) = op.layout.non_1zst_field(bx).expect( |
| "not exactly one non-1-ZST field in a `DispatchFromDyn` type", |
| ); |
| op = op.extract_field(bx, idx); |
| } |
| |
| // 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. |
| llfn = Some(meth::VirtualIndex::from_index(idx).get_fn( |
| bx, |
| meta, |
| op.layout.ty, |
| fn_abi, |
| )); |
| llargs.push(data_ptr); |
| continue 'make_args; |
| } |
| Ref(PlaceValue { llval: data_ptr, llextra: Some(meta), .. }) => { |
| // by-value dynamic dispatch |
| llfn = Some(meth::VirtualIndex::from_index(idx).get_fn( |
| bx, |
| meta, |
| op.layout.ty, |
| fn_abi, |
| )); |
| llargs.push(data_ptr); |
| continue; |
| } |
| Immediate(_) => { |
| // See comment above explaining why we peel these newtypes |
| while !op.layout.ty.is_unsafe_ptr() && !op.layout.ty.is_ref() { |
| let (idx, _) = op.layout.non_1zst_field(bx).expect( |
| "not exactly one non-1-ZST field in a `DispatchFromDyn` type", |
| ); |
| op = op.extract_field(bx, idx); |
| } |
| |
| // Make sure that we've actually unwrapped the rcvr down |
| // to a pointer or ref to `dyn* Trait`. |
| if !op.layout.ty.builtin_deref(true).unwrap().is_dyn_star() { |
| span_bug!(span, "can't codegen a virtual call on {:#?}", op); |
| } |
| let place = op.deref(bx.cx()); |
| let data_place = place.project_field(bx, 0); |
| let meta_place = place.project_field(bx, 1); |
| let meta = bx.load_operand(meta_place); |
| llfn = Some(meth::VirtualIndex::from_index(idx).get_fn( |
| bx, |
| meta.immediate(), |
| op.layout.ty, |
| fn_abi, |
| )); |
| llargs.push(data_place.val.llval); |
| continue; |
| } |
| _ => { |
| 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.node, op.val) { |
| (&mir::Operand::Copy(_), Ref(PlaceValue { llextra: None, .. })) |
| | (&mir::Operand::Constant(_), Ref(PlaceValue { llextra: None, .. })) => { |
| let tmp = PlaceRef::alloca(bx, op.layout); |
| bx.lifetime_start(tmp.val.llval, tmp.layout.size); |
| op.val.store(bx, tmp); |
| op.val = Ref(tmp.val); |
| copied_constant_arguments.push(tmp); |
| } |
| _ => {} |
| } |
| |
| self.codegen_argument(bx, op, &mut llargs, &fn_abi.args[i]); |
| } |
| let num_untupled = untuple.map(|tup| { |
| self.codegen_arguments_untupled( |
| bx, |
| &tup.node, |
| &mut llargs, |
| &fn_abi.args[first_args.len()..], |
| ) |
| }); |
| |
| let needs_location = |
| instance.is_some_and(|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(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(bx, location, &mut llargs, last_arg); |
| } |
| |
| let fn_ptr = match (instance, llfn) { |
| (Some(instance), None) => bx.get_fn_addr(instance), |
| (_, Some(llfn)) => llfn, |
| _ => span_bug!(span, "no instance or llfn for call"), |
| }; |
| helper.do_call( |
| self, |
| bx, |
| fn_abi, |
| fn_ptr, |
| &llargs, |
| destination, |
| unwind, |
| &copied_constant_arguments, |
| instance, |
| mergeable_succ, |
| ) |
| } |
| |
| fn codegen_asm_terminator( |
| &mut self, |
| helper: TerminatorCodegenHelper<'tcx>, |
| bx: &mut Bx, |
| asm_macro: InlineAsmMacro, |
| terminator: &mir::Terminator<'tcx>, |
| template: &[ast::InlineAsmTemplatePiece], |
| operands: &[mir::InlineAsmOperand<'tcx>], |
| options: ast::InlineAsmOptions, |
| line_spans: &[Span], |
| targets: &[mir::BasicBlock], |
| unwind: mir::UnwindAction, |
| instance: Instance<'_>, |
| mergeable_succ: bool, |
| ) -> MergingSucc { |
| 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(bx, value); |
| InlineAsmOperandRef::In { reg, value } |
| } |
| mir::InlineAsmOperand::Out { reg, late, ref place } => { |
| let place = place.map(|place| self.codegen_place(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(bx, in_value); |
| let out_place = |
| out_place.map(|out_place| self.codegen_place(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); |
| 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 const_ = self.monomorphize(value.const_); |
| if let ty::FnDef(def_id, args) = *const_.ty().kind() { |
| let instance = ty::Instance::resolve_for_fn_ptr( |
| bx.tcx(), |
| ty::ParamEnv::reveal_all(), |
| def_id, |
| args, |
| ) |
| .unwrap(); |
| InlineAsmOperandRef::SymFn { instance } |
| } else { |
| span_bug!(span, "invalid type for asm sym (fn)"); |
| } |
| } |
| mir::InlineAsmOperand::SymStatic { def_id } => { |
| InlineAsmOperandRef::SymStatic { def_id } |
| } |
| mir::InlineAsmOperand::Label { target_index } => { |
| InlineAsmOperandRef::Label { label: self.llbb(targets[target_index]) } |
| } |
| }) |
| .collect(); |
| |
| helper.do_inlineasm( |
| self, |
| bx, |
| template, |
| &operands, |
| options, |
| line_spans, |
| if asm_macro.diverges(options) { None } else { targets.get(0).copied() }, |
| unwind, |
| instance, |
| mergeable_succ, |
| ) |
| } |
| |
| pub(crate) fn codegen_block(&mut self, mut bb: mir::BasicBlock) { |
| let llbb = match self.try_llbb(bb) { |
| Some(llbb) => llbb, |
| None => return, |
| }; |
| let bx = &mut Bx::build(self.cx, llbb); |
| let mir = self.mir; |
| |
| // MIR basic blocks stop at any function call. This may not be the case |
| // for the backend's basic blocks, in which case we might be able to |
| // combine multiple MIR basic blocks into a single backend basic block. |
| loop { |
| let data = &mir[bb]; |
| |
| debug!("codegen_block({:?}={:?})", bb, data); |
| |
| for statement in &data.statements { |
| self.codegen_statement(bx, statement); |
| } |
| |
| let merging_succ = self.codegen_terminator(bx, bb, data.terminator()); |
| if let MergingSucc::False = merging_succ { |
| break; |
| } |
| |
| // We are merging the successor into the produced backend basic |
| // block. Record that the successor should be skipped when it is |
| // reached. |
| // |
| // Note: we must not have already generated code for the successor. |
| // This is implicitly ensured by the reverse postorder traversal, |
| // and the assertion explicitly guarantees that. |
| let mut successors = data.terminator().successors(); |
| let succ = successors.next().unwrap(); |
| assert!(matches!(self.cached_llbbs[succ], CachedLlbb::None)); |
| self.cached_llbbs[succ] = CachedLlbb::Skip; |
| bb = succ; |
| } |
| } |
| |
| pub(crate) fn codegen_block_as_unreachable(&mut self, bb: mir::BasicBlock) { |
| let llbb = match self.try_llbb(bb) { |
| Some(llbb) => llbb, |
| None => return, |
| }; |
| let bx = &mut Bx::build(self.cx, llbb); |
| debug!("codegen_block_as_unreachable({:?})", bb); |
| bx.unreachable(); |
| } |
| |
| fn codegen_terminator( |
| &mut self, |
| bx: &mut Bx, |
| bb: mir::BasicBlock, |
| terminator: &'tcx mir::Terminator<'tcx>, |
| ) -> MergingSucc { |
| debug!("codegen_terminator: {:?}", terminator); |
| |
| let helper = TerminatorCodegenHelper { bb, terminator }; |
| |
| let mergeable_succ = || { |
| // Note: any call to `switch_to_block` will invalidate a `true` value |
| // of `mergeable_succ`. |
| let mut successors = terminator.successors(); |
| if let Some(succ) = successors.next() |
| && successors.next().is_none() |
| && let &[succ_pred] = self.mir.basic_blocks.predecessors()[succ].as_slice() |
| { |
| // bb has a single successor, and bb is its only predecessor. This |
| // makes it a candidate for merging. |
| assert_eq!(succ_pred, bb); |
| true |
| } else { |
| false |
| } |
| }; |
| |
| self.set_debug_loc(bx, terminator.source_info); |
| match terminator.kind { |
| mir::TerminatorKind::UnwindResume => { |
| self.codegen_resume_terminator(helper, bx); |
| MergingSucc::False |
| } |
| |
| mir::TerminatorKind::UnwindTerminate(reason) => { |
| self.codegen_terminate_terminator(helper, bx, terminator, reason); |
| MergingSucc::False |
| } |
| |
| mir::TerminatorKind::Goto { target } => { |
| helper.funclet_br(self, bx, target, mergeable_succ()) |
| } |
| |
| mir::TerminatorKind::SwitchInt { ref discr, ref targets } => { |
| self.codegen_switchint_terminator(helper, bx, discr, targets); |
| MergingSucc::False |
| } |
| |
| mir::TerminatorKind::Return => { |
| self.codegen_return_terminator(bx); |
| MergingSucc::False |
| } |
| |
| mir::TerminatorKind::Unreachable => { |
| bx.unreachable(); |
| MergingSucc::False |
| } |
| |
| mir::TerminatorKind::Drop { place, target, unwind, replace: _ } => self |
| .codegen_drop_terminator( |
| helper, |
| bx, |
| &terminator.source_info, |
| place, |
| target, |
| unwind, |
| mergeable_succ(), |
| ), |
| |
| mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, unwind } => self |
| .codegen_assert_terminator( |
| helper, |
| bx, |
| terminator, |
| cond, |
| expected, |
| msg, |
| target, |
| unwind, |
| mergeable_succ(), |
| ), |
| |
| mir::TerminatorKind::Call { |
| ref func, |
| ref args, |
| destination, |
| target, |
| unwind, |
| call_source: _, |
| fn_span, |
| } => self.codegen_call_terminator( |
| helper, |
| bx, |
| terminator, |
| func, |
| args, |
| destination, |
| target, |
| unwind, |
| fn_span, |
| mergeable_succ(), |
| ), |
| mir::TerminatorKind::TailCall { .. } => { |
| // FIXME(explicit_tail_calls): implement tail calls in ssa backend |
| span_bug!( |
| terminator.source_info.span, |
| "`TailCall` terminator is not yet supported by `rustc_codegen_ssa`" |
| ) |
| } |
| mir::TerminatorKind::CoroutineDrop | mir::TerminatorKind::Yield { .. } => { |
| bug!("coroutine ops in codegen") |
| } |
| mir::TerminatorKind::FalseEdge { .. } | mir::TerminatorKind::FalseUnwind { .. } => { |
| bug!("borrowck false edges in codegen") |
| } |
| |
| mir::TerminatorKind::InlineAsm { |
| asm_macro, |
| template, |
| ref operands, |
| options, |
| line_spans, |
| ref targets, |
| unwind, |
| } => self.codegen_asm_terminator( |
| helper, |
| bx, |
| asm_macro, |
| terminator, |
| template, |
| operands, |
| options, |
| line_spans, |
| targets, |
| unwind, |
| self.instance, |
| mergeable_succ(), |
| ), |
| } |
| } |
| |
| fn codegen_argument( |
| &mut self, |
| bx: &mut Bx, |
| op: OperandRef<'tcx, Bx::Value>, |
| llargs: &mut Vec<Bx::Value>, |
| arg: &ArgAbi<'tcx, Ty<'tcx>>, |
| ) { |
| match arg.mode { |
| PassMode::Ignore => return, |
| PassMode::Cast { pad_i32: true, .. } => { |
| // Fill padding with undef value, where applicable. |
| llargs.push(bx.const_undef(bx.reg_backend_type(&Reg::i32()))); |
| } |
| PassMode::Pair(..) => match op.val { |
| Pair(a, b) => { |
| llargs.push(a); |
| llargs.push(b); |
| return; |
| } |
| _ => bug!("codegen_argument: {:?} invalid for pair argument", op), |
| }, |
| PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => match op.val { |
| Ref(PlaceValue { llval: a, llextra: 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 { attrs, .. } => { |
| // Indirect argument may have higher alignment requirements than the type's |
| // alignment. This can happen, e.g. when passing types with <4 byte alignment |
| // on the stack on x86. |
| let required_align = match attrs.pointee_align { |
| Some(pointee_align) => cmp::max(pointee_align, arg.layout.align.abi), |
| None => arg.layout.align.abi, |
| }; |
| let scratch = PlaceValue::alloca(bx, arg.layout.size, required_align); |
| op.val.store(bx, scratch.with_type(arg.layout)); |
| (scratch.llval, scratch.align, true) |
| } |
| PassMode::Cast { .. } => { |
| let scratch = PlaceRef::alloca(bx, arg.layout); |
| op.val.store(bx, scratch); |
| (scratch.val.llval, scratch.val.align, true) |
| } |
| _ => (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false), |
| }, |
| Ref(op_place_val) => match arg.mode { |
| PassMode::Indirect { attrs, .. } => { |
| let required_align = match attrs.pointee_align { |
| Some(pointee_align) => cmp::max(pointee_align, arg.layout.align.abi), |
| None => arg.layout.align.abi, |
| }; |
| if op_place_val.align < required_align { |
| // For `foo(packed.large_field)`, and types with <4 byte alignment on x86, |
| // alignment requirements may be higher than the type's alignment, so copy |
| // to a higher-aligned alloca. |
| let scratch = PlaceValue::alloca(bx, arg.layout.size, required_align); |
| bx.typed_place_copy(scratch, op_place_val, op.layout); |
| (scratch.llval, scratch.align, true) |
| } else { |
| (op_place_val.llval, op_place_val.align, true) |
| } |
| } |
| _ => (op_place_val.llval, op_place_val.align, true), |
| }, |
| ZeroSized => match arg.mode { |
| PassMode::Indirect { on_stack, .. } => { |
| if on_stack { |
| // It doesn't seem like any target can have `byval` ZSTs, so this assert |
| // is here to replace a would-be untested codepath. |
| bug!("ZST {op:?} passed on stack with abi {arg:?}"); |
| } |
| // Though `extern "Rust"` doesn't pass ZSTs, some ABIs pass |
| // a pointer for `repr(C)` structs even when empty, so get |
| // one from an `alloca` (which can be left uninitialized). |
| let scratch = PlaceRef::alloca(bx, arg.layout); |
| (scratch.val.llval, scratch.val.align, true) |
| } |
| _ => bug!("ZST {op:?} wasn't ignored, but was passed with abi {arg:?}"), |
| }, |
| }; |
| |
| if by_ref && !arg.is_indirect() { |
| // Have to load the argument, maybe while casting it. |
| if let PassMode::Cast { cast, pad_i32: _ } = &arg.mode { |
| // The ABI mandates that the value is passed as a different struct representation. |
| // Spill and reload it from the stack to convert from the Rust representation to |
| // the ABI representation. |
| let scratch_size = cast.size(bx); |
| let scratch_align = cast.align(bx); |
| // Note that the ABI type may be either larger or smaller than the Rust type, |
| // due to the presence or absence of trailing padding. For example: |
| // - On some ABIs, the Rust layout { f64, f32, <f32 padding> } may omit padding |
| // when passed by value, making it smaller. |
| // - On some ABIs, the Rust layout { u16, u16, u16 } may be padded up to 8 bytes |
| // when passed by value, making it larger. |
| let copy_bytes = cmp::min(cast.unaligned_size(bx).bytes(), arg.layout.size.bytes()); |
| // Allocate some scratch space... |
| let llscratch = bx.alloca(scratch_size, scratch_align); |
| bx.lifetime_start(llscratch, scratch_size); |
| // ...memcpy the value... |
| bx.memcpy( |
| llscratch, |
| scratch_align, |
| llval, |
| align, |
| bx.const_usize(copy_bytes), |
| MemFlags::empty(), |
| ); |
| // ...and then load it with the ABI type. |
| let cast_ty = bx.cast_backend_type(cast); |
| llval = bx.load(cast_ty, llscratch, scratch_align); |
| bx.lifetime_end(llscratch, scratch_size); |
| } 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<Bx::Value>, |
| args: &[ArgAbi<'tcx, Ty<'tcx>>], |
| ) -> usize { |
| let tuple = self.codegen_operand(bx, operand); |
| |
| // Handle both by-ref and immediate tuples. |
| if let Ref(place_val) = tuple.val { |
| if place_val.llextra.is_some() { |
| bug!("closure arguments must be sized"); |
| } |
| let tuple_ptr = place_val.with_type(tuple.layout); |
| 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 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, |
| source_info: mir::SourceInfo, |
| ) -> OperandRef<'tcx, Bx::Value> { |
| self.mir.caller_location_span(source_info, self.caller_location, bx.tcx(), |span: Span| { |
| let const_loc = bx.tcx().span_as_caller_location(span); |
| OperandRef::from_const(bx, const_loc, bx.tcx().caller_location_ty()) |
| }) |
| } |
| |
| 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(Ty::new_tup(cx.tcx(), &[ |
| Ty::new_mut_ptr(cx.tcx(), 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_new_eh_instructions(self.cx.sess()) { |
| let cleanup_bb = Bx::append_block(self.cx, self.llfn, &format!("funclet_{bb:?}")); |
| let mut cleanup_bx = Bx::build(self.cx, cleanup_bb); |
| let funclet = cleanup_bx.cleanup_pad(None, &[]); |
| cleanup_bx.br(llbb); |
| self.funclets[bb] = Some(funclet); |
| cleanup_bb |
| } else { |
| let cleanup_llbb = Bx::append_block(self.cx, self.llfn, "cleanup"); |
| let mut cleanup_bx = Bx::build(self.cx, cleanup_llbb); |
| |
| let llpersonality = self.cx.eh_personality(); |
| let (exn0, exn1) = cleanup_bx.cleanup_landing_pad(llpersonality); |
| |
| let slot = self.get_personality_slot(&mut cleanup_bx); |
| slot.storage_live(&mut cleanup_bx); |
| Pair(exn0, exn1).store(&mut cleanup_bx, slot); |
| |
| cleanup_bx.br(llbb); |
| cleanup_llbb |
| } |
| } |
| |
| 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 terminate_block(&mut self, reason: UnwindTerminateReason) -> Bx::BasicBlock { |
| if let Some((cached_bb, cached_reason)) = self.terminate_block |
| && reason == cached_reason |
| { |
| return cached_bb; |
| } |
| |
| let funclet; |
| let llbb; |
| let mut bx; |
| if base::wants_new_eh_instructions(self.cx.sess()) { |
| // 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(); |
| // } |
| // |
| // which creates an IR snippet like |
| // |
| // cs_terminate: |
| // %cs = catchswitch within none [%cp_terminate] unwind to caller |
| // cp_terminate: |
| // %cp = catchpad within %cs [null, i32 64, null] |
| // ... |
| |
| llbb = Bx::append_block(self.cx, self.llfn, "cs_terminate"); |
| let cp_llbb = Bx::append_block(self.cx, self.llfn, "cp_terminate"); |
| |
| let mut cs_bx = Bx::build(self.cx, llbb); |
| let cs = cs_bx.catch_switch(None, None, &[cp_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. |
| bx = Bx::build(self.cx, cp_llbb); |
| let null = |
| bx.const_null(bx.type_ptr_ext(bx.cx().data_layout().instruction_address_space)); |
| let sixty_four = bx.const_i32(64); |
| funclet = Some(bx.catch_pad(cs, &[null, sixty_four, null])); |
| } else { |
| llbb = Bx::append_block(self.cx, self.llfn, "terminate"); |
| bx = Bx::build(self.cx, llbb); |
| |
| let llpersonality = self.cx.eh_personality(); |
| bx.filter_landing_pad(llpersonality); |
| |
| funclet = None; |
| } |
| |
| self.set_debug_loc(&mut bx, mir::SourceInfo::outermost(self.mir.span)); |
| |
| let (fn_abi, fn_ptr, instance) = common::build_langcall(&bx, None, reason.lang_item()); |
| if is_call_from_compiler_builtins_to_upstream_monomorphization(bx.tcx(), instance) { |
| bx.abort(); |
| } else { |
| let fn_ty = bx.fn_decl_backend_type(fn_abi); |
| |
| let llret = bx.call(fn_ty, None, Some(fn_abi), fn_ptr, &[], funclet.as_ref(), None); |
| bx.apply_attrs_to_cleanup_callsite(llret); |
| } |
| |
| bx.unreachable(); |
| |
| self.terminate_block = Some((llbb, reason)); |
| 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.try_llbb(bb).unwrap() |
| } |
| |
| /// Like `llbb`, but may fail if the basic block should be skipped. |
| pub(crate) fn try_llbb(&mut self, bb: mir::BasicBlock) -> Option<Bx::BasicBlock> { |
| match self.cached_llbbs[bb] { |
| CachedLlbb::None => { |
| let llbb = Bx::append_block(self.cx, self.llfn, &format!("{bb:?}")); |
| self.cached_llbbs[bb] = CachedLlbb::Some(llbb); |
| Some(llbb) |
| } |
| CachedLlbb::Some(llbb) => Some(llbb), |
| CachedLlbb::Skip => None, |
| } |
| } |
| |
| fn make_return_dest( |
| &mut self, |
| bx: &mut Bx, |
| dest: mir::Place<'tcx>, |
| fn_ret: &ArgAbi<'tcx, Ty<'tcx>>, |
| llargs: &mut Vec<Bx::Value>, |
| intrinsic: Option<ty::IntrinsicDef>, |
| target: Option<BasicBlock>, |
| ) -> ReturnDest<'tcx, Bx::Value> { |
| if target.is_none() { |
| return ReturnDest::Nothing; |
| } |
| // 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::PendingOperand => { |
| // 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.val.llval); |
| ReturnDest::IndirectOperand(tmp, index) |
| } else if intrinsic.is_some() { |
| // 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(_) => { |
| 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.val.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.val.llval); |
| ReturnDest::Nothing |
| } else { |
| ReturnDest::Store(dest) |
| } |
| } |
| |
| // 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.overwrite_local(index, LocalRef::Operand(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.overwrite_local(index, LocalRef::Operand(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), |
| } |
