| //! Inlining pass for MIR functions |
| |
| use rustc_attr as attr; |
| use rustc_hir as hir; |
| use rustc_index::bit_set::BitSet; |
| use rustc_index::vec::Idx; |
| use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs}; |
| use rustc_middle::mir::visit::*; |
| use rustc_middle::mir::*; |
| use rustc_middle::ty::subst::Subst; |
| use rustc_middle::ty::{self, ConstKind, Instance, InstanceDef, ParamEnv, Ty, TyCtxt}; |
| use rustc_span::{hygiene::ExpnKind, ExpnData, Span}; |
| use rustc_target::spec::abi::Abi; |
| |
| use super::simplify::{remove_dead_blocks, CfgSimplifier}; |
| use crate::transform::MirPass; |
| use std::iter; |
| use std::ops::{Range, RangeFrom}; |
| |
| const INSTR_COST: usize = 5; |
| const CALL_PENALTY: usize = 25; |
| const LANDINGPAD_PENALTY: usize = 50; |
| const RESUME_PENALTY: usize = 45; |
| |
| const UNKNOWN_SIZE_COST: usize = 10; |
| |
| pub struct Inline; |
| |
| #[derive(Copy, Clone, Debug)] |
| struct CallSite<'tcx> { |
| callee: Instance<'tcx>, |
| fn_sig: ty::PolyFnSig<'tcx>, |
| block: BasicBlock, |
| target: Option<BasicBlock>, |
| source_info: SourceInfo, |
| } |
| |
| impl<'tcx> MirPass<'tcx> for Inline { |
| fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { |
| if tcx.sess.opts.debugging_opts.mir_opt_level < 2 { |
| return; |
| } |
| |
| if inline(tcx, body) { |
| debug!("running simplify cfg on {:?}", body.source); |
| CfgSimplifier::new(body).simplify(); |
| remove_dead_blocks(body); |
| } |
| } |
| } |
| |
| fn inline(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool { |
| let def_id = body.source.def_id(); |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); |
| |
| // Only do inlining into fn bodies. |
| if !tcx.hir().body_owner_kind(hir_id).is_fn_or_closure() { |
| return false; |
| } |
| if body.source.promoted.is_some() { |
| return false; |
| } |
| |
| let mut this = Inliner { |
| tcx, |
| param_env: tcx.param_env_reveal_all_normalized(body.source.def_id()), |
| codegen_fn_attrs: tcx.codegen_fn_attrs(body.source.def_id()), |
| hir_id, |
| history: Vec::new(), |
| changed: false, |
| }; |
| let blocks = BasicBlock::new(0)..body.basic_blocks().next_index(); |
| this.process_blocks(body, blocks); |
| this.changed |
| } |
| |
| struct Inliner<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| param_env: ParamEnv<'tcx>, |
| /// Caller codegen attributes. |
| codegen_fn_attrs: &'tcx CodegenFnAttrs, |
| /// Caller HirID. |
| hir_id: hir::HirId, |
| /// Stack of inlined instances. |
| history: Vec<Instance<'tcx>>, |
| /// Indicates that the caller body has been modified. |
| changed: bool, |
| } |
| |
| impl Inliner<'tcx> { |
| fn process_blocks(&mut self, caller_body: &mut Body<'tcx>, blocks: Range<BasicBlock>) { |
| for bb in blocks { |
| let callsite = match self.get_valid_function_call(bb, &caller_body[bb], caller_body) { |
| None => continue, |
| Some(it) => it, |
| }; |
| |
| if !self.is_mir_available(&callsite.callee, caller_body) { |
| debug!("MIR unavailable {}", callsite.callee); |
| continue; |
| } |
| |
| let callee_body = self.tcx.instance_mir(callsite.callee.def); |
| if !self.should_inline(callsite, callee_body) { |
| continue; |
| } |
| |
| if !self.tcx.consider_optimizing(|| { |
| format!("Inline {:?} into {}", callee_body.span, callsite.callee) |
| }) { |
| return; |
| } |
| |
| let callee_body = callsite.callee.subst_mir_and_normalize_erasing_regions( |
| self.tcx, |
| self.param_env, |
| callee_body.clone(), |
| ); |
| |
| let old_blocks = caller_body.basic_blocks().next_index(); |
| self.inline_call(callsite, caller_body, callee_body); |
| let new_blocks = old_blocks..caller_body.basic_blocks().next_index(); |
| self.changed = true; |
| |
| self.history.push(callsite.callee); |
| self.process_blocks(caller_body, new_blocks); |
| self.history.pop(); |
| } |
| } |
| |
| fn is_mir_available(&self, callee: &Instance<'tcx>, caller_body: &Body<'tcx>) -> bool { |
| if let InstanceDef::Item(_) = callee.def { |
| if !self.tcx.is_mir_available(callee.def_id()) { |
| return false; |
| } |
| } |
| |
| if let Some(callee_def_id) = callee.def_id().as_local() { |
| let callee_hir_id = self.tcx.hir().local_def_id_to_hir_id(callee_def_id); |
| // Avoid a cycle here by only using `instance_mir` only if we have |
| // a lower `HirId` than the callee. This ensures that the callee will |
| // not inline us. This trick only works without incremental compilation. |
| // So don't do it if that is enabled. Also avoid inlining into generators, |
| // since their `optimized_mir` is used for layout computation, which can |
| // create a cycle, even when no attempt is made to inline the function |
| // in the other direction. |
| !self.tcx.dep_graph.is_fully_enabled() |
| && self.hir_id < callee_hir_id |
| && caller_body.generator_kind.is_none() |
| } else { |
| // This cannot result in a cycle since the callee MIR is from another crate |
| // and is already optimized. |
| true |
| } |
| } |
| |
| fn get_valid_function_call( |
| &self, |
| bb: BasicBlock, |
| bb_data: &BasicBlockData<'tcx>, |
| caller_body: &Body<'tcx>, |
| ) -> Option<CallSite<'tcx>> { |
| // Don't inline calls that are in cleanup blocks. |
| if bb_data.is_cleanup { |
| return None; |
| } |
| |
| // Only consider direct calls to functions |
| let terminator = bb_data.terminator(); |
| if let TerminatorKind::Call { ref func, ref destination, .. } = terminator.kind { |
| let func_ty = func.ty(caller_body, self.tcx); |
| if let ty::FnDef(def_id, substs) = *func_ty.kind() { |
| // To resolve an instance its substs have to be fully normalized. |
| let substs = self.tcx.normalize_erasing_regions(self.param_env, substs); |
| let callee = |
| Instance::resolve(self.tcx, self.param_env, def_id, substs).ok().flatten()?; |
| |
| if let InstanceDef::Virtual(..) | InstanceDef::Intrinsic(_) = callee.def { |
| return None; |
| } |
| |
| let fn_sig = self.tcx.fn_sig(def_id).subst(self.tcx, substs); |
| |
| return Some(CallSite { |
| callee, |
| fn_sig, |
| block: bb, |
| target: destination.map(|(_, target)| target), |
| source_info: terminator.source_info, |
| }); |
| } |
| } |
| |
| None |
| } |
| |
| fn should_inline(&self, callsite: CallSite<'tcx>, callee_body: &Body<'tcx>) -> bool { |
| debug!("should_inline({:?})", callsite); |
| let tcx = self.tcx; |
| |
| if callsite.fn_sig.c_variadic() { |
| debug!("callee is variadic - not inlining"); |
| return false; |
| } |
| |
| let codegen_fn_attrs = tcx.codegen_fn_attrs(callsite.callee.def_id()); |
| |
| let self_features = &self.codegen_fn_attrs.target_features; |
| let callee_features = &codegen_fn_attrs.target_features; |
| if callee_features.iter().any(|feature| !self_features.contains(feature)) { |
| debug!("`callee has extra target features - not inlining"); |
| return false; |
| } |
| |
| if self.codegen_fn_attrs.no_sanitize != codegen_fn_attrs.no_sanitize { |
| debug!("`callee has incompatible no_sanitize attribute - not inlining"); |
| return false; |
| } |
| |
| let hinted = match codegen_fn_attrs.inline { |
| // Just treat inline(always) as a hint for now, |
| // there are cases that prevent inlining that we |
| // need to check for first. |
| attr::InlineAttr::Always => true, |
| attr::InlineAttr::Never => { |
| debug!("`#[inline(never)]` present - not inlining"); |
| return false; |
| } |
| attr::InlineAttr::Hint => true, |
| attr::InlineAttr::None => false, |
| }; |
| |
| // Only inline local functions if they would be eligible for cross-crate |
| // inlining. This is to ensure that the final crate doesn't have MIR that |
| // reference unexported symbols |
| if callsite.callee.def_id().is_local() { |
| if callsite.callee.substs.non_erasable_generics().count() == 0 && !hinted { |
| debug!(" callee is an exported function - not inlining"); |
| return false; |
| } |
| } |
| |
| let mut threshold = if hinted { |
| self.tcx.sess.opts.debugging_opts.inline_mir_hint_threshold |
| } else { |
| self.tcx.sess.opts.debugging_opts.inline_mir_threshold |
| }; |
| |
| if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) { |
| debug!("#[naked] present - not inlining"); |
| return false; |
| } |
| |
| if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::COLD) { |
| debug!("#[cold] present - not inlining"); |
| return false; |
| } |
| |
| // Give a bonus functions with a small number of blocks, |
| // We normally have two or three blocks for even |
| // very small functions. |
| if callee_body.basic_blocks().len() <= 3 { |
| threshold += threshold / 4; |
| } |
| debug!(" final inline threshold = {}", threshold); |
| |
| // FIXME: Give a bonus to functions with only a single caller |
| let mut first_block = true; |
| let mut cost = 0; |
| |
| // Traverse the MIR manually so we can account for the effects of |
| // inlining on the CFG. |
| let mut work_list = vec![START_BLOCK]; |
| let mut visited = BitSet::new_empty(callee_body.basic_blocks().len()); |
| while let Some(bb) = work_list.pop() { |
| if !visited.insert(bb.index()) { |
| continue; |
| } |
| let blk = &callee_body.basic_blocks()[bb]; |
| |
| for stmt in &blk.statements { |
| // Don't count StorageLive/StorageDead in the inlining cost. |
| match stmt.kind { |
| StatementKind::StorageLive(_) |
| | StatementKind::StorageDead(_) |
| | StatementKind::Nop => {} |
| _ => cost += INSTR_COST, |
| } |
| } |
| let term = blk.terminator(); |
| let mut is_drop = false; |
| match term.kind { |
| TerminatorKind::Drop { ref place, target, unwind } |
| | TerminatorKind::DropAndReplace { ref place, target, unwind, .. } => { |
| is_drop = true; |
| work_list.push(target); |
| // If the place doesn't actually need dropping, treat it like |
| // a regular goto. |
| let ty = callsite.callee.subst_mir(self.tcx, &place.ty(callee_body, tcx).ty); |
| if ty.needs_drop(tcx, self.param_env) { |
| cost += CALL_PENALTY; |
| if let Some(unwind) = unwind { |
| cost += LANDINGPAD_PENALTY; |
| work_list.push(unwind); |
| } |
| } else { |
| cost += INSTR_COST; |
| } |
| } |
| |
| TerminatorKind::Unreachable | TerminatorKind::Call { destination: None, .. } |
| if first_block => |
| { |
| // If the function always diverges, don't inline |
| // unless the cost is zero |
| threshold = 0; |
| } |
| |
| TerminatorKind::Call { func: Operand::Constant(ref f), cleanup, .. } => { |
| if let ty::FnDef(def_id, substs) = |
| *callsite.callee.subst_mir(self.tcx, &f.literal.ty).kind() |
| { |
| let substs = self.tcx.normalize_erasing_regions(self.param_env, substs); |
| if let Ok(Some(instance)) = |
| Instance::resolve(self.tcx, self.param_env, def_id, substs) |
| { |
| if callsite.callee == instance || self.history.contains(&instance) { |
| debug!("`callee is recursive - not inlining"); |
| return false; |
| } |
| } |
| // Don't give intrinsics the extra penalty for calls |
| let f = tcx.fn_sig(def_id); |
| if f.abi() == Abi::RustIntrinsic || f.abi() == Abi::PlatformIntrinsic { |
| cost += INSTR_COST; |
| } else { |
| cost += CALL_PENALTY; |
| } |
| } else { |
| cost += CALL_PENALTY; |
| } |
| if cleanup.is_some() { |
| cost += LANDINGPAD_PENALTY; |
| } |
| } |
| TerminatorKind::Assert { cleanup, .. } => { |
| cost += CALL_PENALTY; |
| |
| if cleanup.is_some() { |
| cost += LANDINGPAD_PENALTY; |
| } |
| } |
| TerminatorKind::Resume => cost += RESUME_PENALTY, |
| _ => cost += INSTR_COST, |
| } |
| |
| if !is_drop { |
| for &succ in term.successors() { |
| work_list.push(succ); |
| } |
| } |
| |
| first_block = false; |
| } |
| |
| // Count up the cost of local variables and temps, if we know the size |
| // use that, otherwise we use a moderately-large dummy cost. |
| |
| let ptr_size = tcx.data_layout.pointer_size.bytes(); |
| |
| for v in callee_body.vars_and_temps_iter() { |
| let ty = callsite.callee.subst_mir(self.tcx, &callee_body.local_decls[v].ty); |
| // Cost of the var is the size in machine-words, if we know |
| // it. |
| if let Some(size) = type_size_of(tcx, self.param_env, ty) { |
| cost += (size / ptr_size) as usize; |
| } else { |
| cost += UNKNOWN_SIZE_COST; |
| } |
| } |
| |
| if let attr::InlineAttr::Always = codegen_fn_attrs.inline { |
| debug!("INLINING {:?} because inline(always) [cost={}]", callsite, cost); |
| true |
| } else { |
| if cost <= threshold { |
| debug!("INLINING {:?} [cost={} <= threshold={}]", callsite, cost, threshold); |
| true |
| } else { |
| debug!("NOT inlining {:?} [cost={} > threshold={}]", callsite, cost, threshold); |
| false |
| } |
| } |
| } |
| |
| fn inline_call( |
| &self, |
| callsite: CallSite<'tcx>, |
| caller_body: &mut Body<'tcx>, |
| mut callee_body: Body<'tcx>, |
| ) { |
| let terminator = caller_body[callsite.block].terminator.take().unwrap(); |
| match terminator.kind { |
| TerminatorKind::Call { args, destination, cleanup, .. } => { |
| // If the call is something like `a[*i] = f(i)`, where |
| // `i : &mut usize`, then just duplicating the `a[*i]` |
| // Place could result in two different locations if `f` |
| // writes to `i`. To prevent this we need to create a temporary |
| // borrow of the place and pass the destination as `*temp` instead. |
| fn dest_needs_borrow(place: Place<'_>) -> bool { |
| for elem in place.projection.iter() { |
| match elem { |
| ProjectionElem::Deref | ProjectionElem::Index(_) => return true, |
| _ => {} |
| } |
| } |
| |
| false |
| } |
| |
| let dest = if let Some((destination_place, _)) = destination { |
| if dest_needs_borrow(destination_place) { |
| trace!("creating temp for return destination"); |
| let dest = Rvalue::Ref( |
| self.tcx.lifetimes.re_erased, |
| BorrowKind::Mut { allow_two_phase_borrow: false }, |
| destination_place, |
| ); |
| let dest_ty = dest.ty(caller_body, self.tcx); |
| let temp = Place::from(self.new_call_temp(caller_body, &callsite, dest_ty)); |
| caller_body[callsite.block].statements.push(Statement { |
| source_info: callsite.source_info, |
| kind: StatementKind::Assign(box (temp, dest)), |
| }); |
| self.tcx.mk_place_deref(temp) |
| } else { |
| destination_place |
| } |
| } else { |
| trace!("creating temp for return place"); |
| Place::from(self.new_call_temp(caller_body, &callsite, callee_body.return_ty())) |
| }; |
| |
| // Copy the arguments if needed. |
| let args: Vec<_> = self.make_call_args(args, &callsite, caller_body, &callee_body); |
| |
| let mut integrator = Integrator { |
| args: &args, |
| new_locals: Local::new(caller_body.local_decls.len()).., |
| new_scopes: SourceScope::new(caller_body.source_scopes.len()).., |
| new_blocks: BasicBlock::new(caller_body.basic_blocks().len()).., |
| destination: dest, |
| return_block: callsite.target, |
| cleanup_block: cleanup, |
| in_cleanup_block: false, |
| tcx: self.tcx, |
| callsite_span: callsite.source_info.span, |
| body_span: callee_body.span, |
| always_live_locals: BitSet::new_filled(callee_body.local_decls.len()), |
| }; |
| |
| // Map all `Local`s, `SourceScope`s and `BasicBlock`s to new ones |
| // (or existing ones, in a few special cases) in the caller. |
| integrator.visit_body(&mut callee_body); |
| |
| for scope in &mut callee_body.source_scopes { |
| // FIXME(eddyb) move this into a `fn visit_scope_data` in `Integrator`. |
| if scope.parent_scope.is_none() { |
| let callsite_scope = &caller_body.source_scopes[callsite.source_info.scope]; |
| |
| // Attach the outermost callee scope as a child of the callsite |
| // scope, via the `parent_scope` and `inlined_parent_scope` chains. |
| scope.parent_scope = Some(callsite.source_info.scope); |
| assert_eq!(scope.inlined_parent_scope, None); |
| scope.inlined_parent_scope = if callsite_scope.inlined.is_some() { |
| Some(callsite.source_info.scope) |
| } else { |
| callsite_scope.inlined_parent_scope |
| }; |
| |
| // Mark the outermost callee scope as an inlined one. |
| assert_eq!(scope.inlined, None); |
| scope.inlined = Some((callsite.callee, callsite.source_info.span)); |
| } else if scope.inlined_parent_scope.is_none() { |
| // Make it easy to find the scope with `inlined` set above. |
| scope.inlined_parent_scope = |
| Some(integrator.map_scope(OUTERMOST_SOURCE_SCOPE)); |
| } |
| } |
| |
| // If there are any locals without storage markers, give them storage only for the |
| // duration of the call. |
| for local in callee_body.vars_and_temps_iter() { |
| if integrator.always_live_locals.contains(local) { |
| let new_local = integrator.map_local(local); |
| caller_body[callsite.block].statements.push(Statement { |
| source_info: callsite.source_info, |
| kind: StatementKind::StorageLive(new_local), |
| }); |
| } |
| } |
| if let Some(block) = callsite.target { |
| // To avoid repeated O(n) insert, push any new statements to the end and rotate |
| // the slice once. |
| let mut n = 0; |
| for local in callee_body.vars_and_temps_iter().rev() { |
| if integrator.always_live_locals.contains(local) { |
| let new_local = integrator.map_local(local); |
| caller_body[block].statements.push(Statement { |
| source_info: callsite.source_info, |
| kind: StatementKind::StorageDead(new_local), |
| }); |
| n += 1; |
| } |
| } |
| caller_body[block].statements.rotate_right(n); |
| } |
| |
| // Insert all of the (mapped) parts of the callee body into the caller. |
| caller_body.local_decls.extend( |
| // FIXME(eddyb) make `Range<Local>` iterable so that we can use |
| // `callee_body.local_decls.drain(callee_body.vars_and_temps())` |
| callee_body |
| .vars_and_temps_iter() |
| .map(|local| callee_body.local_decls[local].clone()), |
| ); |
| caller_body.source_scopes.extend(callee_body.source_scopes.drain(..)); |
| caller_body.var_debug_info.extend(callee_body.var_debug_info.drain(..)); |
| caller_body.basic_blocks_mut().extend(callee_body.basic_blocks_mut().drain(..)); |
| |
| caller_body[callsite.block].terminator = Some(Terminator { |
| source_info: callsite.source_info, |
| kind: TerminatorKind::Goto { target: integrator.map_block(START_BLOCK) }, |
| }); |
| |
| // Copy only unevaluated constants from the callee_body into the caller_body. |
| // Although we are only pushing `ConstKind::Unevaluated` consts to |
| // `required_consts`, here we may not only have `ConstKind::Unevaluated` |
| // because we are calling `subst_and_normalize_erasing_regions`. |
| caller_body.required_consts.extend( |
| callee_body.required_consts.iter().copied().filter(|&constant| { |
| matches!(constant.literal.val, ConstKind::Unevaluated(_, _, _)) |
| }), |
| ); |
| } |
| kind => bug!("unexpected terminator kind {:?}", kind), |
| } |
| } |
| |
| fn make_call_args( |
| &self, |
| args: Vec<Operand<'tcx>>, |
| callsite: &CallSite<'tcx>, |
| caller_body: &mut Body<'tcx>, |
| callee_body: &Body<'tcx>, |
| ) -> Vec<Local> { |
| let tcx = self.tcx; |
| |
| // There is a bit of a mismatch between the *caller* of a closure and the *callee*. |
| // The caller provides the arguments wrapped up in a tuple: |
| // |
| // tuple_tmp = (a, b, c) |
| // Fn::call(closure_ref, tuple_tmp) |
| // |
| // meanwhile the closure body expects the arguments (here, `a`, `b`, and `c`) |
| // as distinct arguments. (This is the "rust-call" ABI hack.) Normally, codegen has |
| // the job of unpacking this tuple. But here, we are codegen. =) So we want to create |
| // a vector like |
| // |
| // [closure_ref, tuple_tmp.0, tuple_tmp.1, tuple_tmp.2] |
| // |
| // Except for one tiny wrinkle: we don't actually want `tuple_tmp.0`. It's more convenient |
| // if we "spill" that into *another* temporary, so that we can map the argument |
| // variable in the callee MIR directly to an argument variable on our side. |
| // So we introduce temporaries like: |
| // |
| // tmp0 = tuple_tmp.0 |
| // tmp1 = tuple_tmp.1 |
| // tmp2 = tuple_tmp.2 |
| // |
| // and the vector is `[closure_ref, tmp0, tmp1, tmp2]`. |
| if callsite.fn_sig.abi() == Abi::RustCall && callee_body.spread_arg.is_none() { |
| let mut args = args.into_iter(); |
| let self_ = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body); |
| let tuple = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body); |
| assert!(args.next().is_none()); |
| |
| let tuple = Place::from(tuple); |
| let tuple_tys = if let ty::Tuple(s) = tuple.ty(caller_body, tcx).ty.kind() { |
| s |
| } else { |
| bug!("Closure arguments are not passed as a tuple"); |
| }; |
| |
| // The `closure_ref` in our example above. |
| let closure_ref_arg = iter::once(self_); |
| |
| // The `tmp0`, `tmp1`, and `tmp2` in our example abonve. |
| let tuple_tmp_args = tuple_tys.iter().enumerate().map(|(i, ty)| { |
| // This is e.g., `tuple_tmp.0` in our example above. |
| let tuple_field = |
| Operand::Move(tcx.mk_place_field(tuple, Field::new(i), ty.expect_ty())); |
| |
| // Spill to a local to make e.g., `tmp0`. |
| self.create_temp_if_necessary(tuple_field, callsite, caller_body) |
| }); |
| |
| closure_ref_arg.chain(tuple_tmp_args).collect() |
| } else { |
| args.into_iter() |
| .map(|a| self.create_temp_if_necessary(a, callsite, caller_body)) |
| .collect() |
| } |
| } |
| |
| /// If `arg` is already a temporary, returns it. Otherwise, introduces a fresh |
| /// temporary `T` and an instruction `T = arg`, and returns `T`. |
| fn create_temp_if_necessary( |
| &self, |
| arg: Operand<'tcx>, |
| callsite: &CallSite<'tcx>, |
| caller_body: &mut Body<'tcx>, |
| ) -> Local { |
| // Reuse the operand if it is a moved temporary. |
| if let Operand::Move(place) = &arg { |
| if let Some(local) = place.as_local() { |
| if caller_body.local_kind(local) == LocalKind::Temp { |
| return local; |
| } |
| } |
| } |
| |
| // Otherwise, create a temporary for the argument. |
| trace!("creating temp for argument {:?}", arg); |
| let arg_ty = arg.ty(caller_body, self.tcx); |
| let local = self.new_call_temp(caller_body, callsite, arg_ty); |
| caller_body[callsite.block].statements.push(Statement { |
| source_info: callsite.source_info, |
| kind: StatementKind::Assign(box (Place::from(local), Rvalue::Use(arg))), |
| }); |
| local |
| } |
| |
| /// Introduces a new temporary into the caller body that is live for the duration of the call. |
| fn new_call_temp( |
| &self, |
| caller_body: &mut Body<'tcx>, |
| callsite: &CallSite<'tcx>, |
| ty: Ty<'tcx>, |
| ) -> Local { |
| let local = caller_body.local_decls.push(LocalDecl::new(ty, callsite.source_info.span)); |
| |
| caller_body[callsite.block].statements.push(Statement { |
| source_info: callsite.source_info, |
| kind: StatementKind::StorageLive(local), |
| }); |
| |
| if let Some(block) = callsite.target { |
| caller_body[block].statements.insert( |
| 0, |
| Statement { |
| source_info: callsite.source_info, |
| kind: StatementKind::StorageDead(local), |
| }, |
| ); |
| } |
| |
| local |
| } |
| } |
| |
| fn type_size_of<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| ty: Ty<'tcx>, |
| ) -> Option<u64> { |
| tcx.layout_of(param_env.and(ty)).ok().map(|layout| layout.size.bytes()) |
| } |
| |
| /** |
| * Integrator. |
| * |
| * Integrates blocks from the callee function into the calling function. |
| * Updates block indices, references to locals and other control flow |
| * stuff. |
| */ |
| struct Integrator<'a, 'tcx> { |
| args: &'a [Local], |
| new_locals: RangeFrom<Local>, |
| new_scopes: RangeFrom<SourceScope>, |
| new_blocks: RangeFrom<BasicBlock>, |
| destination: Place<'tcx>, |
| return_block: Option<BasicBlock>, |
| cleanup_block: Option<BasicBlock>, |
| in_cleanup_block: bool, |
| tcx: TyCtxt<'tcx>, |
| callsite_span: Span, |
| body_span: Span, |
| always_live_locals: BitSet<Local>, |
| } |
| |
| impl<'a, 'tcx> Integrator<'a, 'tcx> { |
| fn map_local(&self, local: Local) -> Local { |
| let new = if local == RETURN_PLACE { |
| self.destination.local |
| } else { |
| let idx = local.index() - 1; |
| if idx < self.args.len() { |
| self.args[idx] |
| } else { |
| Local::new(self.new_locals.start.index() + (idx - self.args.len())) |
| } |
| }; |
| trace!("mapping local `{:?}` to `{:?}`", local, new); |
| new |
| } |
| |
| fn map_scope(&self, scope: SourceScope) -> SourceScope { |
| let new = SourceScope::new(self.new_scopes.start.index() + scope.index()); |
| trace!("mapping scope `{:?}` to `{:?}`", scope, new); |
| new |
| } |
| |
| fn map_block(&self, block: BasicBlock) -> BasicBlock { |
| let new = BasicBlock::new(self.new_blocks.start.index() + block.index()); |
| trace!("mapping block `{:?}` to `{:?}`", block, new); |
| new |
| } |
| } |
| |
| impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> { |
| fn tcx(&self) -> TyCtxt<'tcx> { |
| self.tcx |
| } |
| |
| fn visit_local(&mut self, local: &mut Local, _ctxt: PlaceContext, _location: Location) { |
| *local = self.map_local(*local); |
| } |
| |
| fn visit_source_scope(&mut self, scope: &mut SourceScope) { |
| *scope = self.map_scope(*scope); |
| } |
| |
| fn visit_span(&mut self, span: &mut Span) { |
| // Make sure that all spans track the fact that they were inlined. |
| *span = self.callsite_span.fresh_expansion(ExpnData { |
| def_site: self.body_span, |
| ..ExpnData::default(ExpnKind::Inlined, *span, self.tcx.sess.edition(), None) |
| }); |
| } |
| |
| fn visit_place(&mut self, place: &mut Place<'tcx>, context: PlaceContext, location: Location) { |
| for elem in place.projection { |
| // FIXME: Make sure that return place is not used in an indexing projection, since it |
| // won't be rebased as it is supposed to be. |
| assert_ne!(ProjectionElem::Index(RETURN_PLACE), elem); |
| } |
| |
| // If this is the `RETURN_PLACE`, we need to rebase any projections onto it. |
| let dest_proj_len = self.destination.projection.len(); |
| if place.local == RETURN_PLACE && dest_proj_len > 0 { |
| let mut projs = Vec::with_capacity(dest_proj_len + place.projection.len()); |
| projs.extend(self.destination.projection); |
| projs.extend(place.projection); |
| |
| place.projection = self.tcx.intern_place_elems(&*projs); |
| } |
| // Handles integrating any locals that occur in the base |
| // or projections |
| self.super_place(place, context, location) |
| } |
| |
| fn visit_basic_block_data(&mut self, block: BasicBlock, data: &mut BasicBlockData<'tcx>) { |
| self.in_cleanup_block = data.is_cleanup; |
| self.super_basic_block_data(block, data); |
| self.in_cleanup_block = false; |
| } |
| |
| fn visit_retag(&mut self, kind: &mut RetagKind, place: &mut Place<'tcx>, loc: Location) { |
| self.super_retag(kind, place, loc); |
| |
| // We have to patch all inlined retags to be aware that they are no longer |
| // happening on function entry. |
| if *kind == RetagKind::FnEntry { |
| *kind = RetagKind::Default; |
| } |
| } |
| |
| fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) { |
| if let StatementKind::StorageLive(local) | StatementKind::StorageDead(local) = |
| statement.kind |
| { |
| self.always_live_locals.remove(local); |
| } |
| self.super_statement(statement, location); |
| } |
| |
| fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, loc: Location) { |
| // Don't try to modify the implicit `_0` access on return (`return` terminators are |
| // replaced down below anyways). |
| if !matches!(terminator.kind, TerminatorKind::Return) { |
| self.super_terminator(terminator, loc); |
| } |
| |
| match terminator.kind { |
| TerminatorKind::GeneratorDrop | TerminatorKind::Yield { .. } => bug!(), |
| TerminatorKind::Goto { ref mut target } => { |
| *target = self.map_block(*target); |
| } |
| TerminatorKind::SwitchInt { ref mut targets, .. } => { |
| for tgt in targets.all_targets_mut() { |
| *tgt = self.map_block(*tgt); |
| } |
| } |
| TerminatorKind::Drop { ref mut target, ref mut unwind, .. } |
| | TerminatorKind::DropAndReplace { ref mut target, ref mut unwind, .. } => { |
| *target = self.map_block(*target); |
| if let Some(tgt) = *unwind { |
| *unwind = Some(self.map_block(tgt)); |
| } else if !self.in_cleanup_block { |
| // Unless this drop is in a cleanup block, add an unwind edge to |
| // the original call's cleanup block |
| *unwind = self.cleanup_block; |
| } |
| } |
| TerminatorKind::Call { ref mut destination, ref mut cleanup, .. } => { |
| if let Some((_, ref mut tgt)) = *destination { |
| *tgt = self.map_block(*tgt); |
| } |
| if let Some(tgt) = *cleanup { |
| *cleanup = Some(self.map_block(tgt)); |
| } else if !self.in_cleanup_block { |
| // Unless this call is in a cleanup block, add an unwind edge to |
| // the original call's cleanup block |
| *cleanup = self.cleanup_block; |
| } |
| } |
| TerminatorKind::Assert { ref mut target, ref mut cleanup, .. } => { |
| *target = self.map_block(*target); |
| if let Some(tgt) = *cleanup { |
| *cleanup = Some(self.map_block(tgt)); |
| } else if !self.in_cleanup_block { |
| // Unless this assert is in a cleanup block, add an unwind edge to |
| // the original call's cleanup block |
| *cleanup = self.cleanup_block; |
| } |
| } |
| TerminatorKind::Return => { |
| terminator.kind = if let Some(tgt) = self.return_block { |
| TerminatorKind::Goto { target: tgt } |
| } else { |
| TerminatorKind::Unreachable |
| } |
| } |
| TerminatorKind::Resume => { |
| if let Some(tgt) = self.cleanup_block { |
| terminator.kind = TerminatorKind::Goto { target: tgt } |
| } |
| } |
| TerminatorKind::Abort => {} |
| TerminatorKind::Unreachable => {} |
| TerminatorKind::FalseEdge { ref mut real_target, ref mut imaginary_target } => { |
| *real_target = self.map_block(*real_target); |
| *imaginary_target = self.map_block(*imaginary_target); |
| } |
| TerminatorKind::FalseUnwind { real_target: _, unwind: _ } => |
| // see the ordering of passes in the optimized_mir query. |
| { |
| bug!("False unwinds should have been removed before inlining") |
| } |
| TerminatorKind::InlineAsm { ref mut destination, .. } => { |
| if let Some(ref mut tgt) = *destination { |
| *tgt = self.map_block(*tgt); |
| } |
| } |
| } |
| } |
| } |
