| use std::cmp; | |
| use rustc_abi::{Align, BackendRepr, ExternAbi, HasDataLayout, Reg, Size, WrappingRange}; | |
| use rustc_ast as ast; | |
| use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece}; | |
| use rustc_data_structures::packed::Pu128; | |
| use rustc_hir::lang_items::LangItem; | |
| use rustc_lint_defs::builtin::TAIL_CALL_TRACK_CALLER; | |
| use rustc_middle::mir::{self, AssertKind, 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, TypeVisitableExt}; | |
| use rustc_middle::{bug, span_bug}; | |
| use rustc_session::config::OptLevel; | |
| use rustc_span::{Span, Spanned}; | |
| use rustc_target::callconv::{ArgAbi, ArgAttributes, CastTarget, FnAbi, PassMode}; | |
| 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, | |
| } | |
| /// Indicates to the call terminator codegen whether a call | |
| /// is a normal call or an explicit tail call. | |
| #[derive(Debug, PartialEq)] | |
| enum CallKind { | |
| Normal, | |
| Tail, | |
| } | |
| /// 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, | |
| lifetime_ends_after_call: &[(Bx::Value, Size)], | |
| instance: Option<Instance<'tcx>>, | |
| kind: CallKind, | |
| mergeable_succ: bool, | |
| ) -> MergingSucc { | |
| let tcx = bx.tcx(); | |
| if let Some(instance) = instance | |
| && is_call_from_compiler_builtins_to_upstream_monomorphization(tcx, instance) | |
| { | |
| if destination.is_some() { | |
| let caller_def = fx.instance.def_id(); | |
| let e = CompilerBuiltinsCannotCall { | |
| span: tcx.def_span(caller_def), | |
| caller: with_no_trimmed_paths!(tcx.def_path_str(caller_def)), | |
| callee: with_no_trimmed_paths!(tcx.def_path_str(instance.def_id())), | |
| }; | |
| tcx.dcx().emit_err(e); | |
| } 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 caller_attrs = if bx.tcx().def_kind(fx.instance.def_id()).has_codegen_attrs() { | |
| Some(bx.tcx().codegen_instance_attrs(fx.instance.def)) | |
| } else { | |
| None | |
| }; | |
| let caller_attrs = caller_attrs.as_deref(); | |
| 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_wasm_eh(fx.cx.tcx().sess) { | |
| // For wasm, we need to generate a nested `cleanuppad within %outer_pad` | |
| // to catch exceptions during cleanup and call `panic_in_cleanup`. | |
| Some(fx.terminate_block(reason, Some(self.bb))) | |
| } else 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. | |
| None | |
| } else { | |
| Some(fx.terminate_block(reason, None)) | |
| } | |
| } | |
| }; | |
| if kind == CallKind::Tail { | |
| bx.tail_call(fn_ty, caller_attrs, fn_abi, fn_ptr, llargs, self.funclet(fx), instance); | |
| return MergingSucc::False; | |
| } | |
| if let Some(unwind_block) = unwind_block { | |
| let ret_llbb = if let Some((_, target)) = destination { | |
| self.llbb_with_cleanup(fx, target) | |
| } else { | |
| fx.unreachable_block() | |
| }; | |
| let invokeret = bx.invoke( | |
| fn_ty, | |
| caller_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, size) in lifetime_ends_after_call { | |
| bx.lifetime_end(tmp, size); | |
| } | |
| fx.store_return(bx, ret_dest, &fn_abi.ret, invokeret); | |
| } | |
| MergingSucc::False | |
| } else { | |
| let llret = bx.call( | |
| fn_ty, | |
| caller_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, size) in lifetime_ends_after_call { | |
| bx.lifetime_end(tmp, 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, None)), | |
| 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 { | |
| self.llbb_with_cleanup(fx, 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 { | |
| self.llbb_with_cleanup(fx, 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 otherwise = targets.otherwise(); | |
| let lltarget = helper.llbb_with_cleanup(self, target); | |
| let llotherwise = helper.llbb_with_cleanup(self, otherwise); | |
| let target_cold = self.cold_blocks[target]; | |
| let otherwise_cold = self.cold_blocks[otherwise]; | |
| // If `target_cold == otherwise_cold`, the branches have the same weight | |
| // so there is no expectation. If they differ, the `target` branch is expected | |
| // when the `otherwise` branch is cold. | |
| let expect = if target_cold == otherwise_cold { None } else { Some(otherwise_cold) }; | |
| if switch_ty == bx.tcx().types.bool { | |
| // Don't generate trivial icmps when switching on bool. | |
| match test_value { | |
| 0 => { | |
| let expect = expect.map(|e| !e); | |
| bx.cond_br_with_expect(discr_value, llotherwise, lltarget, expect); | |
| } | |
| 1 => { | |
| bx.cond_br_with_expect(discr_value, lltarget, llotherwise, expect); | |
| } | |
| _ => 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_with_expect(cmp, lltarget, llotherwise, expect); | |
| } | |
| } else if target_iter.len() == 2 | |
| && self.mir[targets.otherwise()].is_empty_unreachable() | |
| && targets.all_values().contains(&Pu128(0)) | |
| && targets.all_values().contains(&Pu128(1)) | |
| { | |
| // This is the really common case for `bool`, `Option`, etc. | |
| // By using `trunc nuw` we communicate that other values are | |
| // impossible without needing `switch` or `assume`s. | |
| let true_bb = targets.target_for_value(1); | |
| let false_bb = targets.target_for_value(0); | |
| let true_ll = helper.llbb_with_cleanup(self, true_bb); | |
| let false_ll = helper.llbb_with_cleanup(self, false_bb); | |
| let expected_cond_value = if self.cx.sess().opts.optimize == OptLevel::No { | |
| None | |
| } else { | |
| match (self.cold_blocks[true_bb], self.cold_blocks[false_bb]) { | |
| // Same coldness, no expectation | |
| (true, true) | (false, false) => None, | |
| // Different coldness, expect the non-cold one | |
| (true, false) => Some(false), | |
| (false, true) => Some(true), | |
| } | |
| }; | |
| let bool_ty = bx.tcx().types.bool; | |
| let cond = if switch_ty == bool_ty { | |
| discr_value | |
| } else { | |
| let bool_llty = bx.immediate_backend_type(bx.layout_of(bool_ty)); | |
| bx.unchecked_utrunc(discr_value, bool_llty) | |
| }; | |
| bx.cond_br_with_expect(cond, true_ll, false_ll, expected_cond_value); | |
| } 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 { | |
| let otherwise = targets.otherwise(); | |
| let otherwise_cold = self.cold_blocks[otherwise]; | |
| let otherwise_unreachable = self.mir[otherwise].is_empty_unreachable(); | |
| let cold_count = targets.iter().filter(|(_, target)| self.cold_blocks[*target]).count(); | |
| let none_cold = cold_count == 0; | |
| let all_cold = cold_count == targets.iter().len(); | |
| if (none_cold && (!otherwise_cold || otherwise_unreachable)) | |
| || (all_cold && (otherwise_cold || otherwise_unreachable)) | |
| { | |
| // All targets have the same weight, | |
| // or `otherwise` is unreachable and it's the only target with a different weight. | |
| bx.switch( | |
| discr_value, | |
| helper.llbb_with_cleanup(self, targets.otherwise()), | |
| target_iter | |
| .map(|(value, target)| (value, helper.llbb_with_cleanup(self, target))), | |
| ); | |
| } else { | |
| // Targets have different weights | |
| bx.switch_with_weights( | |
| discr_value, | |
| helper.llbb_with_cleanup(self, targets.otherwise()), | |
| otherwise_cold, | |
| target_iter.map(|(value, target)| { | |
| (value, helper.llbb_with_cleanup(self, target), self.cold_blocks[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::arg(va_list_arg_idx)] { | |
| LocalRef::Place(va_list) => { | |
| bx.va_end(va_list.val.llval); | |
| // Explicitly end the lifetime of the `va_list`, improves LLVM codegen. | |
| bx.lifetime_end(va_list.val.llval, va_list.layout.size); | |
| } | |
| _ => bug!("C-variadic function must have a `VaList` place"), | |
| } | |
| } | |
| if self.fn_abi.ret.layout.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, | |
| move_annotation: None, | |
| }, | |
| 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"), | |
| }; | |
| load_cast(bx, cast_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(_, _) => { | |
| // 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, | |
| ) | |
| } | |
| _ => ( | |
| 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), | |
| CallKind::Normal, | |
| !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 { len, 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 { required, 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]) | |
| } | |
| AssertKind::NullPointerDereference => { | |
| // It's `fn panic_null_pointer_dereference()`, | |
| // `#[track_caller]` adds an implicit argument. | |
| (LangItem::PanicNullPointerDereference, vec![location]) | |
| } | |
| AssertKind::InvalidEnumConstruction(source) => { | |
| let source = self.codegen_operand(bx, source).immediate(); | |
| // It's `fn panic_invalid_enum_construction(source: u128)`, | |
| // `#[track_caller]` adds an implicit argument. | |
| (LangItem::PanicInvalidEnumConstruction, vec![source, 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, 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), | |
| CallKind::Normal, | |
| 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, 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), | |
| CallKind::Normal, | |
| 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: 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. | |
| let Some(requirement) = ValidityRequirement::from_intrinsic(intrinsic.name) else { | |
| return None; | |
| }; | |
| let ty = instance.args.type_at(0); | |
| let is_valid = bx | |
| .tcx() | |
| .check_validity_requirement((requirement, bx.typing_env().as_query_input(ty))) | |
| .expect("expect to have layout during codegen"); | |
| if is_valid { | |
| // a NOP | |
| let target = target.unwrap(); | |
| return Some(helper.funclet_br(self, bx, target, mergeable_succ)); | |
| } | |
| let layout = bx.layout_of(ty); | |
| let msg_str = with_no_visible_paths!({ | |
| with_no_trimmed_paths!({ | |
| if layout.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, source_info.span, LangItem::PanicNounwind); | |
| // Codegen the actual panic invoke/call. | |
| Some(helper.do_call( | |
| self, | |
| bx, | |
| fn_abi, | |
| llfn, | |
| &[msg.0, msg.1], | |
| target.as_ref().map(|bb| (ReturnDest::Nothing, *bb)), | |
| unwind, | |
| &[], | |
| Some(instance), | |
| CallKind::Normal, | |
| mergeable_succ, | |
| )) | |
| } | |
| 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, | |
| kind: CallKind, | |
| mergeable_succ: bool, | |
| ) -> MergingSucc { | |
| let source_info = mir::SourceInfo { span: fn_span, ..terminator.source_info }; | |
| // 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, generic_args) => { | |
| let instance = ty::Instance::expect_resolve( | |
| bx.tcx(), | |
| bx.typing_env(), | |
| def_id, | |
| generic_args, | |
| fn_span, | |
| ); | |
| match instance.def { | |
| // We don't need AsyncDropGlueCtorShim here because it is not `noop func`, | |
| // it is `func returning noop future` | |
| ty::InstanceKind::DropGlue(_, None) => { | |
| // Empty drop glue; a no-op. | |
| let target = target.unwrap(); | |
| return helper.funclet_br(self, bx, target, mergeable_succ); | |
| } | |
| 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 result_layout = | |
| self.cx.layout_of(self.monomorphized_place_ty(destination.as_ref())); | |
| let (result, store_in_local) = if result_layout.is_zst() { | |
| ( | |
| PlaceRef::new_sized(bx.const_undef(bx.type_ptr()), result_layout), | |
| None, | |
| ) | |
| } else if let Some(local) = destination.as_local() { | |
| match self.locals[local] { | |
| LocalRef::Place(dest) => (dest, None), | |
| LocalRef::UnsizedPlace(_) => bug!("return type must be sized"), | |
| LocalRef::PendingOperand => { | |
| // Currently, intrinsics always need a location to store | |
| // the result, so we create a temporary `alloca` for the | |
| // result. | |
| let tmp = PlaceRef::alloca(bx, result_layout); | |
| tmp.storage_live(bx); | |
| (tmp, Some(local)) | |
| } | |
| LocalRef::Operand(_) => { | |
| bug!("place local already assigned to"); | |
| } | |
| } | |
| } else { | |
| (self.codegen_place(bx, destination.as_ref()), None) | |
| }; | |
| if result.val.align < result.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"); | |
| } | |
| let args: Vec<_> = | |
| args.iter().map(|arg| self.codegen_operand(bx, &arg.node)).collect(); | |
| match self.codegen_intrinsic_call(bx, instance, &args, result, source_info) | |
| { | |
| Ok(()) => { | |
| if let Some(local) = store_in_local { | |
| let op = bx.load_operand(result); | |
| result.storage_dead(bx); | |
| self.overwrite_local(local, LocalRef::Operand(op)); | |
| self.debug_introduce_local(bx, local); | |
| } | |
| 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!( | |
| fn_span, | |
| "intrinsic {} must be overridden by codegen backend, but isn't", | |
| intrinsic.name, | |
| ); | |
| } | |
| (Some(instance), None) | |
| } | |
| } | |
| } | |
| _ if kind == CallKind::Tail | |
| && instance.def.requires_caller_location(bx.tcx()) => | |
| { | |
| if let Some(hir_id) = | |
| terminator.source_info.scope.lint_root(&self.mir.source_scopes) | |
| { | |
| bx.tcx().emit_node_lint(TAIL_CALL_TRACK_CALLER, hir_id, rustc_errors::DiagDecorator(|d| { | |
| _ = d.primary_message("tail calling a function marked with `#[track_caller]` has no special effect").span(fn_span) | |
| })); | |
| } | |
| let instance = ty::Instance::resolve_for_fn_ptr( | |
| bx.tcx(), | |
| bx.typing_env(), | |
| def_id, | |
| generic_args, | |
| ) | |
| .unwrap(); | |
| (None, Some(bx.get_fn_addr(instance))) | |
| } | |
| _ => (Some(instance), None), | |
| } | |
| } | |
| ty::FnPtr(..) => (None, Some(callee.immediate())), | |
| _ => bug!("{} is not callable", callee.layout.ty), | |
| }; | |
| if let Some(instance) = instance | |
| && let Some(name) = bx.tcx().codegen_fn_attrs(instance.def_id()).symbol_name | |
| && name.as_str().starts_with("llvm.") | |
| // This is the only LLVM intrinsic we use that unwinds | |
| // FIXME either add unwind support to codegen_llvm_intrinsic_call or replace usage of | |
| // this intrinsic with something else | |
| && name.as_str() != "llvm.wasm.throw" | |
| { | |
| assert!(!instance.args.has_infer()); | |
| assert!(!instance.args.has_escaping_bound_vars()); | |
| let result_layout = | |
| self.cx.layout_of(self.monomorphized_place_ty(destination.as_ref())); | |
| let return_dest = if result_layout.is_zst() { | |
| ReturnDest::Nothing | |
| } else if let Some(index) = destination.as_local() { | |
| match self.locals[index] { | |
| LocalRef::Place(dest) => ReturnDest::Store(dest), | |
| LocalRef::UnsizedPlace(_) => bug!("return type must be sized"), | |
| LocalRef::PendingOperand => { | |
| // Handle temporary places, specifically `Operand` ones, as | |
| // they don't have `alloca`s. | |
| ReturnDest::DirectOperand(index) | |
| } | |
| LocalRef::Operand(_) => bug!("place local already assigned to"), | |
| } | |
| } else { | |
| ReturnDest::Store(self.codegen_place(bx, destination.as_ref())) | |
| }; | |
| let args = | |
| args.into_iter().map(|arg| self.codegen_operand(bx, &arg.node)).collect::<Vec<_>>(); | |
| self.set_debug_loc(bx, source_info); | |
| let llret = | |
| bx.codegen_llvm_intrinsic_call(instance, &args, self.mir[helper.bb].is_cleanup); | |
| if let Some(target) = target { | |
| self.store_return( | |
| bx, | |
| return_dest, | |
| &ArgAbi { layout: result_layout, mode: PassMode::Direct(ArgAttributes::new()) }, | |
| llret, | |
| ); | |
| return helper.funclet_br(self, bx, target, mergeable_succ); | |
| } else { | |
| bx.unreachable(); | |
| return MergingSucc::False; | |
| } | |
| } | |
| // 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 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 mut llargs = Vec::with_capacity(arg_count); | |
| // We still need to call `make_return_dest` even if there's no `target`, since | |
| // `fn_abi.ret` could be `PassMode::Indirect`, even if it is uninhabited, | |
| // and `make_return_dest` adds the return-place indirect pointer to `llargs`. | |
| let destination = match kind { | |
| CallKind::Normal => { | |
| let return_dest = self.make_return_dest(bx, destination, &fn_abi.ret, &mut llargs); | |
| target.map(|target| (return_dest, target)) | |
| } | |
| CallKind::Tail => { | |
| if fn_abi.ret.is_indirect() { | |
| match self.make_return_dest(bx, destination, &fn_abi.ret, &mut llargs) { | |
| ReturnDest::Nothing => {} | |
| _ => bug!( | |
| "tail calls to functions with indirect returns cannot store into a destination" | |
| ), | |
| } | |
| } | |
| None | |
| } | |
| }; | |
| // Split the rust-call tupled arguments off. | |
| let (first_args, untuple) = if sig.abi() == ExternAbi::RustCall | |
| && let Some((tup, args)) = args.split_last() | |
| { | |
| (args, Some(tup)) | |
| } else { | |
| (args, None) | |
| }; | |
| // Special logic for tail calls with `PassMode::Indirect { on_stack: false, .. }` arguments. | |
| // | |
| // Normally an indirect argument that is allocated in the caller's stack frame | |
| // would be passed as a pointer into the callee's stack frame. | |
| // For tail calls, that would be unsound, because the caller's | |
| // stack frame is overwritten by the callee's stack frame. | |
| // | |
| // Therefore we store the argument for the callee in the corresponding caller's slot. | |
| // Because guaranteed tail calls demand that the caller's signature matches the callee's, | |
| // the corresponding slot has the correct type. | |
| // | |
| // To handle cases like the one below, the tail call arguments must first be copied to a | |
| // temporary, and only then copied to the caller's argument slots. | |
| // | |
| // ``` | |
| // // A struct big enough that it is not passed via registers. | |
| // pub struct Big([u64; 4]); | |
| // | |
| // fn swapper(a: Big, b: Big) -> (Big, Big) { | |
| // become swapper_helper(b, a); | |
| // } | |
| // ``` | |
| let mut tail_call_temporaries = vec![]; | |
| if kind == CallKind::Tail { | |
| tail_call_temporaries = vec![None; first_args.len()]; | |
| // Copy the arguments that use `PassMode::Indirect { on_stack: false , ..}` | |
| // to temporary stack allocations. See the comment above. | |
| for (i, arg) in first_args.iter().enumerate() { | |
| if !matches!(fn_abi.args[i].mode, PassMode::Indirect { on_stack: false, .. }) { | |
| continue; | |
| } | |
| let op = self.codegen_operand(bx, &arg.node); | |
| let tmp = PlaceRef::alloca(bx, op.layout); | |
| bx.lifetime_start(tmp.val.llval, tmp.layout.size); | |
| op.store_with_annotation(bx, tmp); | |
| tail_call_temporaries[i] = Some(tmp); | |
| } | |
| } | |
| // When generating arguments we sometimes introduce temporary allocations with lifetime | |
| // that extend for the duration of a call. Keep track of those allocations and their sizes | |
| // to generate `lifetime_end` when the call returns. | |
| let mut lifetime_ends_after_call: Vec<(Bx::Value, Size)> = Vec::new(); | |
| '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, instance.map(|i| 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_raw_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(self, bx, idx.as_usize()); | |
| } | |
| // 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; | |
| } | |
| _ => { | |
| span_bug!(fn_span, "can't codegen a virtual call on {:#?}", op); | |
| } | |
| } | |
| } | |
| let by_move = if let PassMode::Indirect { on_stack: false, .. } = fn_abi.args[i].mode | |
| && kind == CallKind::Tail | |
| { | |
| // Special logic for tail calls with `PassMode::Indirect { on_stack: false, .. }` arguments. | |
| // | |
| // Normally an indirect argument that is allocated in the caller's stack frame | |
| // would be passed as a pointer into the callee's stack frame. | |
| // For tail calls, that would be unsound, because the caller's | |
| // stack frame is overwritten by the callee's stack frame. | |
| // | |
| // To handle the case, we introduce `tail_call_temporaries` to copy arguments into | |
| // temporaries, then copy back to the caller's argument slots. | |
| // Finally, we pass the caller's argument slots as arguments. | |
| // | |
| // To do that, the argument must be MUST-by-move value. | |
| let Some(tmp) = tail_call_temporaries[i].take() else { | |
| span_bug!(fn_span, "missing temporary for indirect tail call argument #{i}") | |
| }; | |
| let local = self.mir.args_iter().nth(i).unwrap(); | |
| match &self.locals[local] { | |
| LocalRef::Place(arg) => { | |
| bx.typed_place_copy(arg.val, tmp.val, fn_abi.args[i].layout); | |
| op.val = Ref(arg.val); | |
| } | |
| LocalRef::Operand(arg) => { | |
| let Ref(place_value) = arg.val else { | |
| bug!("only `Ref` should use `PassMode::Indirect`"); | |
| }; | |
| bx.typed_place_copy(place_value, tmp.val, fn_abi.args[i].layout); | |
| op.val = arg.val; | |
| } | |
| LocalRef::UnsizedPlace(_) => { | |
| span_bug!(fn_span, "unsized types are not supported") | |
| } | |
| LocalRef::PendingOperand => { | |
| span_bug!(fn_span, "argument local should not be pending") | |
| } | |
| }; | |
| bx.lifetime_end(tmp.val.llval, tmp.layout.size); | |
| true | |
| } else { | |
| matches!(arg.node, mir::Operand::Move(_)) | |
| }; | |
| self.codegen_argument( | |
| bx, | |
| op, | |
| by_move, | |
| &mut llargs, | |
| &fn_abi.args[i], | |
| &mut lifetime_ends_after_call, | |
| ); | |
| } | |
| let num_untupled = untuple.map(|tup| { | |
| self.codegen_arguments_untupled( | |
| bx, | |
| &tup.node, | |
| &mut llargs, | |
| &fn_abi.args[first_args.len()..], | |
| &mut lifetime_ends_after_call, | |
| ) | |
| }); | |
| 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, 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, | |
| /* by_move */ false, | |
| &mut llargs, | |
| last_arg, | |
| &mut lifetime_ends_after_call, | |
| ); | |
| } | |
| let fn_ptr = match (instance, llfn) { | |
| (Some(instance), None) => bx.get_fn_addr(instance), | |
| (_, Some(llfn)) => llfn, | |
| _ => span_bug!(fn_span, "no instance or llfn for call"), | |
| }; | |
| self.set_debug_loc(bx, source_info); | |
| helper.do_call( | |
| self, | |
| bx, | |
| fn_abi, | |
| fn_ptr, | |
| &llargs, | |
| destination, | |
| unwind, | |
| &lifetime_ends_after_call, | |
| instance, | |
| kind, | |
| 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(), | |
| bx.typing_env(), | |
| 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); | |
| } | |
| self.codegen_stmt_debuginfos(bx, &data.after_last_stmt_debuginfos); | |
| 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: _, drop, async_fut } => { | |
| assert!( | |
| async_fut.is_none() && drop.is_none(), | |
| "Async Drop must be expanded or reset to sync before codegen" | |
| ); | |
| 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, | |
| CallKind::Normal, | |
| mergeable_succ(), | |
| ), | |
| mir::TerminatorKind::TailCall { ref func, ref args, fn_span } => self | |
| .codegen_call_terminator( | |
| helper, | |
| bx, | |
| terminator, | |
| func, | |
| args, | |
| mir::Place::from(mir::RETURN_PLACE), | |
| None, | |
| mir::UnwindAction::Unreachable, | |
| fn_span, | |
| CallKind::Tail, | |
| mergeable_succ(), | |
| ), | |
| 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>, | |
| by_move: bool, | |
| llargs: &mut Vec<Bx::Value>, | |
| arg: &ArgAbi<'tcx, Ty<'tcx>>, | |
| lifetime_ends_after_call: &mut Vec<(Bx::Value, Size)>, | |
| ) { | |
| 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); | |
| bx.lifetime_start(scratch.llval, arg.layout.size); | |
| op.store_with_annotation(bx, scratch.with_type(arg.layout)); | |
| lifetime_ends_after_call.push((scratch.llval, arg.layout.size)); | |
| (scratch.llval, scratch.align, true) | |
| } | |
| PassMode::Cast { .. } => { | |
| let scratch = PlaceRef::alloca(bx, arg.layout); | |
| op.store_with_annotation(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, on_stack, .. } => { | |
| // 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 required_align = match attrs.pointee_align { | |
| Some(pointee_align) => cmp::max(pointee_align, arg.layout.align.abi), | |
| None => arg.layout.align.abi, | |
| }; | |
| // Copy to an alloca when the argument is neither by-val nor by-move. | |
| if op_place_val.align < required_align || (!on_stack && !by_move) { | |
| let scratch = PlaceValue::alloca(bx, arg.layout.size, required_align); | |
| bx.lifetime_start(scratch.llval, arg.layout.size); | |
| op.store_with_annotation(bx, scratch.with_type(arg.layout)); | |
| lifetime_ends_after_call.push((scratch.llval, arg.layout.size)); | |
| (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(), | |
| None, | |
| ); | |
| // ...and then load it with the ABI type. | |
| llval = load_cast(bx, cast, 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 BackendRepr::Scalar(scalar) = arg.layout.backend_repr { | |
| 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_scalar(llval, scalar); | |
| } | |
| } | |
| } | |
| 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>>], | |
| lifetime_ends_after_call: &mut Vec<(Bx::Value, Size)>, | |
| ) -> usize { | |
| let tuple = self.codegen_operand(bx, operand); | |
| let by_move = matches!(operand, mir::Operand::Move(_)); | |
| // 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, | |
| by_move, | |
| llargs, | |
| &args[i], | |
| lifetime_ends_after_call, | |
| ); | |
| } | |
| } else { | |
| // If the tuple is immediate, the elements are as well. | |
| for i in 0..tuple.layout.fields.count() { | |
| let op = tuple.extract_field(self, bx, i); | |
| self.codegen_argument(bx, op, by_move, llargs, &args[i], lifetime_ends_after_call); | |
| } | |
| } | |
| tuple.layout.fields.count() | |
| } | |
| pub(super) 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, | |
| outer_catchpad_bb: Option<mir::BasicBlock>, | |
| ) -> Bx::BasicBlock { | |
| // mb_funclet_bb should be present if and only if the target is wasm and | |
| // we're terminating because of an unwind in a cleanup block. In that | |
| // case we have nested funclets and the inner catch_switch needs to know | |
| // what outer catch_pad it is contained in. | |
| debug_assert!( | |
| outer_catchpad_bb.is_some() | |
| == (base::wants_wasm_eh(self.cx.tcx().sess) | |
| && reason == UnwindTerminateReason::InCleanup) | |
| ); | |
| // When we aren't in a wasm InCleanup block, there's only one terminate | |
| // block needed so we cache at START_BLOCK index. | |
| let mut cache_bb = mir::START_BLOCK; | |
| // In wasm eh InCleanup, use the outer funclet's cleanup BB as the cache | |
| // key. | |
| if let Some(outer_bb) = outer_catchpad_bb { | |
| let cleanup_kinds = | |
| self.cleanup_kinds.as_ref().expect("cleanup_kinds required for funclets"); | |
| cache_bb = cleanup_kinds[outer_bb] | |
| .funclet_bb(outer_bb) | |
| .expect("funclet_bb should be in a funclet"); | |
| // Ensure the outer funclet is created first | |
| if self.funclets[cache_bb].is_none() { | |
| self.landing_pad_for(cache_bb); | |
| } | |
| } | |
| if let Some((cached_bb, cached_reason)) = self.terminate_blocks[cache_bb] | |
| && 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] | |
| // ... | |
| // | |
| // By contrast, on WebAssembly targets, we specifically _do_ want to | |
| // catch foreign exceptions. The situation with MSVC is a | |
| // regrettable hack which we don't want to extend to other targets | |
| // unless necessary. For WebAssembly, to generate catch(...) and | |
| // catch only C++ exception instead of generating a catch_all, we | |
| // need to call the intrinsics @llvm.wasm.get.exception and | |
| // @llvm.wasm.get.ehselector in the catch pad. Since we don't do | |
| // this, we generate a catch_all. We originally got this behavior | |
| // by accident but it luckily matches our intention. | |
| llbb = Bx::append_block(self.cx, self.llfn, "cs_terminate"); | |
| let mut cs_bx = Bx::build(self.cx, llbb); | |
| // For wasm InCleanup blocks, our catch_switch is nested within the | |
| // outer catchpad, so we need to provide it as the parent value to | |
| // catch_switch. | |
| let mut outer_cleanuppad = None; | |
| if outer_catchpad_bb.is_some() { | |
| // Get the outer funclet's catchpad | |
| let outer_funclet = self.funclets[cache_bb] | |
| .as_ref() | |
| .expect("landing_pad_for didn't create funclet"); | |
| outer_cleanuppad = Some(cs_bx.get_funclet_cleanuppad(outer_funclet)); | |
| } | |
| let cp_llbb = Bx::append_block(self.cx, self.llfn, "cp_terminate"); | |
| let cs = cs_bx.catch_switch(outer_cleanuppad, None, &[cp_llbb]); | |
| drop(cs_bx); | |
| bx = Bx::build(self.cx, cp_llbb); | |
| let null = | |
| bx.const_null(bx.type_ptr_ext(bx.cx().data_layout().instruction_address_space)); | |
| // The `null` in first argument here is actually a RTTI type | |
| // descriptor for the C++ personality function, but `catch (...)` | |
| // has no type so it's null. | |
| let args = if base::wants_msvc_seh(self.cx.sess()) { | |
| // This bitmask is a single `HT_IsStdDotDot` flag, which | |
| // represents that this is a C++-style `catch (...)` block that | |
| // only captures programmatic exceptions, not all SEH | |
| // exceptions. The second `null` points to a non-existent | |
| // `alloca` instruction, which an LLVM pass would inline into | |
| // the initial SEH frame allocation. | |
| let adjectives = bx.const_i32(0x40); | |
| &[null, adjectives, null] as &[_] | |
| } else { | |
| // Specifying more arguments than necessary usually doesn't | |
| // hurt, but the `WasmEHPrepare` LLVM pass does not recognize | |
| // anything other than a single `null` as a `catch_all` block, | |
| // leading to problems down the line during instruction | |
| // selection. | |
| &[null] as &[_] | |
| }; | |
| funclet = Some(bx.catch_pad(cs, args)); | |
| // On wasm, if we wanted to generate a catch(...) and only catch C++ | |
| // exceptions, we'd call @llvm.wasm.get.exception and | |
| // @llvm.wasm.get.ehselector selectors here. We want a catch_all so | |
| // we leave them out. This is intentionally diverging from the MSVC | |
| // behavior. | |
| } 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, self.mir.span, 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_blocks[cache_bb] = 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>, | |
| ) -> 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::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 { | |
| ReturnDest::DirectOperand(index) | |
| }; | |
| } | |
| LocalRef::Operand(_) => { | |
| bug!("place local already assigned to"); | |
| } | |
| } | |
| } else { | |
| self.codegen_place(bx, dest.as_ref()) | |
| }; | |
| 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), | |
| } | |
| fn load_cast<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( | |
| bx: &mut Bx, | |
| cast: &CastTarget, | |
| ptr: Bx::Value, | |
| align: Align, | |
| ) -> Bx::Value { | |
| let cast_ty = bx.cast_backend_type(cast); | |
| if let Some(offset_from_start) = cast.rest_offset { | |
| assert!(cast.prefix[1..].iter().all(|p| p.is_none())); | |
| assert_eq!(cast.rest.unit.size, cast.rest.total); | |
| let first_ty = bx.reg_backend_type(&cast.prefix[0].unwrap()); | |
| let second_ty = bx.reg_backend_type(&cast.rest.unit); | |
| let first = bx.load(first_ty, ptr, align); | |
| let second_ptr = bx.inbounds_ptradd(ptr, bx.const_usize(offset_from_start.bytes())); | |
| let second = bx.load(second_ty, second_ptr, align.restrict_for_offset(offset_from_start)); | |
| let res = bx.cx().const_poison(cast_ty); | |
| let res = bx.insert_value(res, first, 0); | |
| bx.insert_value(res, second, 1) | |
| } else { | |
| bx.load(cast_ty, ptr, align) | |
| } | |
| } | |
| pub fn store_cast<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( | |
| bx: &mut Bx, | |
| cast: &CastTarget, | |
| value: Bx::Value, | |
| ptr: Bx::Value, | |
| align: Align, | |
| ) { | |
| if let Some(offset_from_start) = cast.rest_offset { | |
| assert!(cast.prefix[1..].iter().all(|p| p.is_none())); | |
| assert_eq!(cast.rest.unit.size, cast.rest.total); | |
| assert!(cast.prefix[0].is_some()); | |
| let first = bx.extract_value(value, 0); | |
| let second = bx.extract_value(value, 1); | |
| bx.store(first, ptr, align); | |
| let second_ptr = bx.inbounds_ptradd(ptr, bx.const_usize(offset_from_start.bytes())); | |
| bx.store(second, second_ptr, align.restrict_for_offset(offset_from_start)); | |
| } else { | |
| bx.store(value, ptr, align); | |
| }; | |
| } |