981 lines
39 KiB
Rust
981 lines
39 KiB
Rust
//! Inlining pass for MIR functions
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use rustc_attr::InlineAttr;
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use rustc_hir as hir;
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use rustc_index::bit_set::BitSet;
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use rustc_index::vec::Idx;
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use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
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use rustc_middle::mir::visit::*;
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use rustc_middle::mir::*;
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use rustc_middle::ty::subst::Subst;
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use rustc_middle::ty::{self, ConstKind, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
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use rustc_span::{hygiene::ExpnKind, ExpnData, Span};
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use rustc_target::spec::abi::Abi;
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use super::simplify::{remove_dead_blocks, CfgSimplifier};
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use crate::transform::MirPass;
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use std::iter;
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use std::ops::{Range, RangeFrom};
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crate mod cycle;
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const INSTR_COST: usize = 5;
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const CALL_PENALTY: usize = 25;
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const LANDINGPAD_PENALTY: usize = 50;
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const RESUME_PENALTY: usize = 45;
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const UNKNOWN_SIZE_COST: usize = 10;
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pub struct Inline;
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#[derive(Copy, Clone, Debug)]
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struct CallSite<'tcx> {
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callee: Instance<'tcx>,
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fn_sig: ty::PolyFnSig<'tcx>,
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block: BasicBlock,
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target: Option<BasicBlock>,
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source_info: SourceInfo,
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}
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/// Returns true if MIR inlining is enabled in the current compilation session.
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crate fn is_enabled(tcx: TyCtxt<'_>) -> bool {
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if tcx.sess.opts.debugging_opts.instrument_coverage {
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// Since `Inline` happens after `InstrumentCoverage`, the function-specific coverage
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// counters can be invalidated, such as by merging coverage counter statements from
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// a pre-inlined function into a different function. This kind of change is invalid,
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// so inlining must be skipped. Note: This check is performed here so inlining can
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// be disabled without preventing other optimizations (regardless of `mir_opt_level`).
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return false;
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}
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if let Some(enabled) = tcx.sess.opts.debugging_opts.inline_mir {
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return enabled;
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}
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tcx.sess.mir_opt_level() >= 3
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}
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impl<'tcx> MirPass<'tcx> for Inline {
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fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
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if !is_enabled(tcx) {
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return;
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}
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let span = trace_span!("inline", body = %tcx.def_path_str(body.source.def_id()));
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let _guard = span.enter();
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if inline(tcx, body) {
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debug!("running simplify cfg on {:?}", body.source);
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CfgSimplifier::new(body).simplify();
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remove_dead_blocks(body);
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}
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}
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}
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fn inline(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool {
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let def_id = body.source.def_id();
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let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
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// Only do inlining into fn bodies.
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if !tcx.hir().body_owner_kind(hir_id).is_fn_or_closure() {
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return false;
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}
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if body.source.promoted.is_some() {
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return false;
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}
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let mut this = Inliner {
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tcx,
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param_env: tcx.param_env_reveal_all_normalized(body.source.def_id()),
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codegen_fn_attrs: tcx.codegen_fn_attrs(body.source.def_id()),
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hir_id,
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history: Vec::new(),
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changed: false,
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};
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let blocks = BasicBlock::new(0)..body.basic_blocks().next_index();
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this.process_blocks(body, blocks);
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this.changed
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}
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struct Inliner<'tcx> {
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tcx: TyCtxt<'tcx>,
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param_env: ParamEnv<'tcx>,
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/// Caller codegen attributes.
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codegen_fn_attrs: &'tcx CodegenFnAttrs,
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/// Caller HirID.
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hir_id: hir::HirId,
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/// Stack of inlined Instances.
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history: Vec<ty::Instance<'tcx>>,
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/// Indicates that the caller body has been modified.
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changed: bool,
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}
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impl Inliner<'tcx> {
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fn process_blocks(&mut self, caller_body: &mut Body<'tcx>, blocks: Range<BasicBlock>) {
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for bb in blocks {
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let bb_data = &caller_body[bb];
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if bb_data.is_cleanup {
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continue;
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}
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let callsite = match self.resolve_callsite(caller_body, bb, bb_data) {
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None => continue,
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Some(it) => it,
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};
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let span = trace_span!("process_blocks", %callsite.callee, ?bb);
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let _guard = span.enter();
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match self.try_inlining(caller_body, &callsite) {
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Err(reason) => {
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debug!("not-inlined {} [{}]", callsite.callee, reason);
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continue;
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}
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Ok(new_blocks) => {
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debug!("inlined {}", callsite.callee);
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self.changed = true;
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self.history.push(callsite.callee);
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self.process_blocks(caller_body, new_blocks);
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self.history.pop();
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}
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}
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}
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}
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/// Attempts to inline a callsite into the caller body. When successful returns basic blocks
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/// containing the inlined body. Otherwise returns an error describing why inlining didn't take
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/// place.
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fn try_inlining(
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&self,
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caller_body: &mut Body<'tcx>,
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callsite: &CallSite<'tcx>,
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) -> Result<std::ops::Range<BasicBlock>, &'static str> {
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let callee_attrs = self.tcx.codegen_fn_attrs(callsite.callee.def_id());
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self.check_codegen_attributes(callsite, callee_attrs)?;
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self.check_mir_is_available(caller_body, &callsite.callee)?;
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let callee_body = self.tcx.instance_mir(callsite.callee.def);
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self.check_mir_body(callsite, callee_body, callee_attrs)?;
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if !self.tcx.consider_optimizing(|| {
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format!("Inline {:?} into {}", callee_body.span, callsite.callee)
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}) {
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return Err("optimization fuel exhausted");
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}
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let callee_body = callsite.callee.subst_mir_and_normalize_erasing_regions(
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self.tcx,
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self.param_env,
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callee_body.clone(),
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);
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let old_blocks = caller_body.basic_blocks().next_index();
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self.inline_call(caller_body, &callsite, callee_body);
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let new_blocks = old_blocks..caller_body.basic_blocks().next_index();
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Ok(new_blocks)
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}
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fn check_mir_is_available(
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&self,
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caller_body: &Body<'tcx>,
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callee: &Instance<'tcx>,
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) -> Result<(), &'static str> {
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if callee.def_id() == caller_body.source.def_id() {
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return Err("self-recursion");
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}
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match callee.def {
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InstanceDef::Item(_) => {
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// If there is no MIR available (either because it was not in metadata or
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// because it has no MIR because it's an extern function), then the inliner
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// won't cause cycles on this.
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if !self.tcx.is_mir_available(callee.def_id()) {
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return Err("item MIR unavailable");
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}
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}
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// These have no own callable MIR.
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InstanceDef::Intrinsic(_) | InstanceDef::Virtual(..) => {
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return Err("instance without MIR (intrinsic / virtual)");
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}
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// This cannot result in an immediate cycle since the callee MIR is a shim, which does
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// not get any optimizations run on it. Any subsequent inlining may cause cycles, but we
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// do not need to catch this here, we can wait until the inliner decides to continue
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// inlining a second time.
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InstanceDef::VtableShim(_)
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| InstanceDef::ReifyShim(_)
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| InstanceDef::FnPtrShim(..)
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| InstanceDef::ClosureOnceShim { .. }
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| InstanceDef::DropGlue(..)
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| InstanceDef::CloneShim(..) => return Ok(()),
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}
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if self.tcx.is_constructor(callee.def_id()) {
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trace!("constructors always have MIR");
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// Constructor functions cannot cause a query cycle.
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return Ok(());
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}
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if let Some(callee_def_id) = callee.def_id().as_local() {
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let callee_hir_id = self.tcx.hir().local_def_id_to_hir_id(callee_def_id);
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// Avoid inlining into generators,
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// since their `optimized_mir` is used for layout computation, which can
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// create a cycle, even when no attempt is made to inline the function
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// in the other direction.
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if caller_body.generator.is_some() {
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return Err("local generator (query cycle avoidance)");
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}
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// Avoid a cycle here by only using `instance_mir` only if we have
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// a lower `HirId` than the callee. This ensures that the callee will
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// not inline us. This trick only works without incremental compilation.
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// So don't do it if that is enabled.
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if !self.tcx.dep_graph.is_fully_enabled() && self.hir_id < callee_hir_id {
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return Ok(());
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}
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// If we know for sure that the function we're calling will itself try to
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// call us, then we avoid inlining that function.
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if self
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.tcx
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.mir_callgraph_reachable((*callee, caller_body.source.def_id().expect_local()))
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{
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return Err("caller might be reachable from callee (query cycle avoidance)");
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}
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Ok(())
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} else {
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// This cannot result in an immediate cycle since the callee MIR is from another crate
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// and is already optimized. Any subsequent inlining may cause cycles, but we do
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// not need to catch this here, we can wait until the inliner decides to continue
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// inlining a second time.
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trace!("functions from other crates always have MIR");
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Ok(())
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}
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}
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fn resolve_callsite(
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&self,
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caller_body: &Body<'tcx>,
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bb: BasicBlock,
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bb_data: &BasicBlockData<'tcx>,
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) -> Option<CallSite<'tcx>> {
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// Only consider direct calls to functions
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let terminator = bb_data.terminator();
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if let TerminatorKind::Call { ref func, ref destination, .. } = terminator.kind {
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let func_ty = func.ty(caller_body, self.tcx);
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if let ty::FnDef(def_id, substs) = *func_ty.kind() {
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// To resolve an instance its substs have to be fully normalized.
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let substs = self.tcx.normalize_erasing_regions(self.param_env, substs);
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let callee =
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Instance::resolve(self.tcx, self.param_env, def_id, substs).ok().flatten()?;
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if let InstanceDef::Virtual(..) | InstanceDef::Intrinsic(_) = callee.def {
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return None;
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}
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let fn_sig = self.tcx.fn_sig(def_id).subst(self.tcx, substs);
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return Some(CallSite {
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callee,
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fn_sig,
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block: bb,
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target: destination.map(|(_, target)| target),
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source_info: terminator.source_info,
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});
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}
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}
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None
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}
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/// Returns an error if inlining is not possible based on codegen attributes alone. A success
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/// indicates that inlining decision should be based on other criteria.
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fn check_codegen_attributes(
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&self,
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callsite: &CallSite<'tcx>,
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callee_attrs: &CodegenFnAttrs,
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) -> Result<(), &'satic str> {
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if let InlineAttr::Never = callee_attrs.inline {
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return Err("never inline hint");
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}
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// Only inline local functions if they would be eligible for cross-crate
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// inlining. This is to ensure that the final crate doesn't have MIR that
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// reference unexported symbols
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if callsite.callee.def_id().is_local() {
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let is_generic = callsite.callee.substs.non_erasable_generics().next().is_some();
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if !is_generic && !callee_attrs.requests_inline() {
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return Err("not exported");
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}
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}
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if callsite.fn_sig.c_variadic() {
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return Err("C variadic");
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}
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if callee_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
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return Err("naked");
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}
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if callee_attrs.flags.contains(CodegenFnAttrFlags::COLD) {
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return Err("cold");
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}
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if callee_attrs.no_sanitize != self.codegen_fn_attrs.no_sanitize {
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return Err("incompatible sanitizer set");
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}
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if callee_attrs.instruction_set != self.codegen_fn_attrs.instruction_set {
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return Err("incompatible instruction set");
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}
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for feature in &callee_attrs.target_features {
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if !self.codegen_fn_attrs.target_features.contains(feature) {
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return Err("incompatible target feature");
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}
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}
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Ok(())
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}
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/// Returns inlining decision that is based on the examination of callee MIR body.
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/// Assumes that codegen attributes have been checked for compatibility already.
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#[instrument(level = "debug", skip(self, callee_body))]
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fn check_mir_body(
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&self,
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callsite: &CallSite<'tcx>,
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callee_body: &Body<'tcx>,
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callee_attrs: &CodegenFnAttrs,
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) -> Result<(), &'static str> {
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let tcx = self.tcx;
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let mut threshold = if callee_attrs.requests_inline() {
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self.tcx.sess.opts.debugging_opts.inline_mir_hint_threshold.unwrap_or(100)
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} else {
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self.tcx.sess.opts.debugging_opts.inline_mir_threshold.unwrap_or(50)
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};
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// Give a bonus functions with a small number of blocks,
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// We normally have two or three blocks for even
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// very small functions.
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if callee_body.basic_blocks().len() <= 3 {
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threshold += threshold / 4;
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}
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debug!(" final inline threshold = {}", threshold);
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// FIXME: Give a bonus to functions with only a single caller
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let mut first_block = true;
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let mut cost = 0;
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// Traverse the MIR manually so we can account for the effects of
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// inlining on the CFG.
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let mut work_list = vec![START_BLOCK];
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let mut visited = BitSet::new_empty(callee_body.basic_blocks().len());
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while let Some(bb) = work_list.pop() {
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if !visited.insert(bb.index()) {
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continue;
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}
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let blk = &callee_body.basic_blocks()[bb];
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for stmt in &blk.statements {
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// Don't count StorageLive/StorageDead in the inlining cost.
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match stmt.kind {
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StatementKind::StorageLive(_)
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| StatementKind::StorageDead(_)
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| StatementKind::Nop => {}
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_ => cost += INSTR_COST,
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}
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}
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let term = blk.terminator();
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let mut is_drop = false;
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match term.kind {
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TerminatorKind::Drop { ref place, target, unwind }
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| TerminatorKind::DropAndReplace { ref place, target, unwind, .. } => {
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is_drop = true;
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work_list.push(target);
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// If the place doesn't actually need dropping, treat it like
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// a regular goto.
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let ty = callsite.callee.subst_mir(self.tcx, &place.ty(callee_body, tcx).ty);
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if ty.needs_drop(tcx, self.param_env) {
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cost += CALL_PENALTY;
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if let Some(unwind) = unwind {
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cost += LANDINGPAD_PENALTY;
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work_list.push(unwind);
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}
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} else {
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cost += INSTR_COST;
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}
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}
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TerminatorKind::Unreachable | TerminatorKind::Call { destination: None, .. }
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if first_block =>
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{
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// If the function always diverges, don't inline
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// unless the cost is zero
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threshold = 0;
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}
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TerminatorKind::Call { func: Operand::Constant(ref f), cleanup, .. } => {
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if let ty::FnDef(def_id, substs) =
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*callsite.callee.subst_mir(self.tcx, &f.literal.ty()).kind()
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{
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let substs = self.tcx.normalize_erasing_regions(self.param_env, substs);
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if let Ok(Some(instance)) =
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Instance::resolve(self.tcx, self.param_env, def_id, substs)
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{
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if callsite.callee.def_id() == instance.def_id() {
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return Err("self-recursion");
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} else if self.history.contains(&instance) {
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return Err("already inlined");
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}
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}
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// Don't give intrinsics the extra penalty for calls
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let f = tcx.fn_sig(def_id);
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if f.abi() == Abi::RustIntrinsic || f.abi() == Abi::PlatformIntrinsic {
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cost += INSTR_COST;
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} else {
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cost += CALL_PENALTY;
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}
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} else {
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cost += CALL_PENALTY;
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}
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if cleanup.is_some() {
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cost += LANDINGPAD_PENALTY;
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}
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}
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TerminatorKind::Assert { cleanup, .. } => {
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cost += CALL_PENALTY;
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if cleanup.is_some() {
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cost += LANDINGPAD_PENALTY;
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}
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}
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TerminatorKind::Resume => cost += RESUME_PENALTY,
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_ => cost += INSTR_COST,
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}
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if !is_drop {
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for &succ in term.successors() {
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work_list.push(succ);
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}
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}
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first_block = false;
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}
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// Count up the cost of local variables and temps, if we know the size
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// use that, otherwise we use a moderately-large dummy cost.
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let ptr_size = tcx.data_layout.pointer_size.bytes();
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for v in callee_body.vars_and_temps_iter() {
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let ty = callsite.callee.subst_mir(self.tcx, &callee_body.local_decls[v].ty);
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// Cost of the var is the size in machine-words, if we know
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// it.
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if let Some(size) = type_size_of(tcx, self.param_env, ty) {
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cost += ((size + ptr_size - 1) / ptr_size) as usize;
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} else {
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cost += UNKNOWN_SIZE_COST;
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}
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}
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if let InlineAttr::Always = callee_attrs.inline {
|
|
debug!("INLINING {:?} because inline(always) [cost={}]", callsite, cost);
|
|
Ok(())
|
|
} else {
|
|
if cost <= threshold {
|
|
debug!("INLINING {:?} [cost={} <= threshold={}]", callsite, cost, threshold);
|
|
Ok(())
|
|
} else {
|
|
debug!("NOT inlining {:?} [cost={} > threshold={}]", callsite, cost, threshold);
|
|
Err("cost above threshold")
|
|
}
|
|
}
|
|
}
|
|
|
|
fn inline_call(
|
|
&self,
|
|
caller_body: &mut Body<'tcx>,
|
|
callsite: &CallSite<'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(|&ct| {
|
|
match ct.literal.const_for_ty() {
|
|
Some(ct) => matches!(ct.val, ConstKind::Unevaluated(_, _, _)),
|
|
None => true,
|
|
}
|
|
}),
|
|
);
|
|
}
|
|
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) {
|
|
let mut expn_data =
|
|
ExpnData::default(ExpnKind::Inlined, *span, self.tcx.sess.edition(), None);
|
|
expn_data.def_site = self.body_span;
|
|
// Make sure that all spans track the fact that they were inlined.
|
|
*span = self.callsite_span.fresh_expansion(expn_data);
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|