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8bb4bdeb 1//! Inlining pass for MIR functions
923072b8 2use crate::deref_separator::deref_finder;
6a06907d 3use rustc_attr::InlineAttr;
9c376795 4use rustc_hir::def_id::DefId;
e74abb32 5use rustc_index::bit_set::BitSet;
29967ef6 6use rustc_index::vec::Idx;
1b1a35ee 7use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
ba9703b0
XL
8use rustc_middle::mir::visit::*;
9use rustc_middle::mir::*;
f2b60f7d
FG
10use rustc_middle::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
11use rustc_session::config::OptLevel;
5e7ed085 12use rustc_span::{hygiene::ExpnKind, ExpnData, LocalExpnId, Span};
f2b60f7d 13use rustc_target::abi::VariantIdx;
ba9703b0 14use rustc_target::spec::abi::Abi;
8bb4bdeb 15
487cf647
FG
16use crate::simplify::{remove_dead_blocks, CfgSimplifier};
17use crate::util;
c295e0f8 18use crate::MirPass;
ff7c6d11 19use std::iter;
29967ef6 20use std::ops::{Range, RangeFrom};
8bb4bdeb 21
923072b8 22pub(crate) mod cycle;
5869c6ff 23
8bb4bdeb
XL
24const INSTR_COST: usize = 5;
25const CALL_PENALTY: usize = 25;
ba9703b0
XL
26const LANDINGPAD_PENALTY: usize = 50;
27const RESUME_PENALTY: usize = 45;
8bb4bdeb
XL
28
29const UNKNOWN_SIZE_COST: usize = 10;
30
9c376795
FG
31const TOP_DOWN_DEPTH_LIMIT: usize = 5;
32
8bb4bdeb
XL
33pub struct Inline;
34
abe05a73 35#[derive(Copy, Clone, Debug)]
8bb4bdeb 36struct CallSite<'tcx> {
29967ef6 37 callee: Instance<'tcx>,
fc512014 38 fn_sig: ty::PolyFnSig<'tcx>,
29967ef6
XL
39 block: BasicBlock,
40 target: Option<BasicBlock>,
41 source_info: SourceInfo,
8bb4bdeb
XL
42}
43
e1599b0c 44impl<'tcx> MirPass<'tcx> for Inline {
a2a8927a 45 fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
064997fb 46 if let Some(enabled) = sess.opts.unstable_opts.inline_mir {
a2a8927a 47 return enabled;
5869c6ff
XL
48 }
49
f2b60f7d
FG
50 match sess.mir_opt_level() {
51 0 | 1 => false,
52 2 => {
53 (sess.opts.optimize == OptLevel::Default
54 || sess.opts.optimize == OptLevel::Aggressive)
55 && sess.opts.incremental == None
56 }
57 _ => true,
58 }
a2a8927a
XL
59 }
60
61 fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
5869c6ff
XL
62 let span = trace_span!("inline", body = %tcx.def_path_str(body.source.def_id()));
63 let _guard = span.enter();
29967ef6
XL
64 if inline(tcx, body) {
65 debug!("running simplify cfg on {:?}", body.source);
66 CfgSimplifier::new(body).simplify();
17df50a5 67 remove_dead_blocks(tcx, body);
923072b8 68 deref_finder(tcx, body);
7cac9316
XL
69 }
70 }
71}
8bb4bdeb 72
a2a8927a 73fn inline<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool {
5e7ed085 74 let def_id = body.source.def_id().expect_local();
29967ef6
XL
75
76 // Only do inlining into fn bodies.
5e7ed085 77 if !tcx.hir().body_owner_kind(def_id).is_fn_or_closure() {
29967ef6
XL
78 return false;
79 }
80 if body.source.promoted.is_some() {
81 return false;
82 }
a2a8927a
XL
83 // Avoid inlining into generators, since their `optimized_mir` is used for layout computation,
84 // which can create a cycle, even when no attempt is made to inline the function in the other
85 // direction.
86 if body.generator.is_some() {
87 return false;
88 }
29967ef6 89
5099ac24 90 let param_env = tcx.param_env_reveal_all_normalized(def_id);
5099ac24 91
9c376795
FG
92 let mut this = Inliner {
93 tcx,
94 param_env,
95 codegen_fn_attrs: tcx.codegen_fn_attrs(def_id),
96 history: Vec::new(),
97 changed: false,
98 };
f2b60f7d 99 let blocks = BasicBlock::new(0)..body.basic_blocks.next_index();
29967ef6
XL
100 this.process_blocks(body, blocks);
101 this.changed
102}
103
dc9dc135
XL
104struct Inliner<'tcx> {
105 tcx: TyCtxt<'tcx>,
29967ef6
XL
106 param_env: ParamEnv<'tcx>,
107 /// Caller codegen attributes.
1b1a35ee 108 codegen_fn_attrs: &'tcx CodegenFnAttrs,
9c376795
FG
109 /// Stack of inlined instances.
110 /// We only check the `DefId` and not the substs because we want to
111 /// avoid inlining cases of polymorphic recursion.
112 /// The number of `DefId`s is finite, so checking history is enough
113 /// to ensure that we do not loop endlessly while inlining.
114 history: Vec<DefId>,
29967ef6
XL
115 /// Indicates that the caller body has been modified.
116 changed: bool,
7cac9316 117}
8bb4bdeb 118
a2a8927a 119impl<'tcx> Inliner<'tcx> {
29967ef6 120 fn process_blocks(&mut self, caller_body: &mut Body<'tcx>, blocks: Range<BasicBlock>) {
9c376795
FG
121 // How many callsites in this body are we allowed to inline? We need to limit this in order
122 // to prevent super-linear growth in MIR size
123 let inline_limit = match self.history.len() {
124 0 => usize::MAX,
125 1..=TOP_DOWN_DEPTH_LIMIT => 1,
126 _ => return,
127 };
128 let mut inlined_count = 0;
29967ef6 129 for bb in blocks {
6a06907d
XL
130 let bb_data = &caller_body[bb];
131 if bb_data.is_cleanup {
132 continue;
133 }
134
5e7ed085
FG
135 let Some(callsite) = self.resolve_callsite(caller_body, bb, bb_data) else {
136 continue;
29967ef6 137 };
6a06907d 138
5869c6ff
XL
139 let span = trace_span!("process_blocks", %callsite.callee, ?bb);
140 let _guard = span.enter();
141
6a06907d
XL
142 match self.try_inlining(caller_body, &callsite) {
143 Err(reason) => {
144 debug!("not-inlined {} [{}]", callsite.callee, reason);
145 continue;
146 }
9c376795 147 Ok(new_blocks) => {
6a06907d
XL
148 debug!("inlined {}", callsite.callee);
149 self.changed = true;
9c376795
FG
150 inlined_count += 1;
151 if inlined_count == inline_limit {
152 return;
153 }
154 self.history.push(callsite.callee.def_id());
155 self.process_blocks(caller_body, new_blocks);
156 self.history.pop();
6a06907d 157 }
8bb4bdeb 158 }
6a06907d
XL
159 }
160 }
8bb4bdeb 161
6a06907d
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162 /// Attempts to inline a callsite into the caller body. When successful returns basic blocks
163 /// containing the inlined body. Otherwise returns an error describing why inlining didn't take
164 /// place.
165 fn try_inlining(
166 &self,
167 caller_body: &mut Body<'tcx>,
168 callsite: &CallSite<'tcx>,
169 ) -> Result<std::ops::Range<BasicBlock>, &'static str> {
170 let callee_attrs = self.tcx.codegen_fn_attrs(callsite.callee.def_id());
171 self.check_codegen_attributes(callsite, callee_attrs)?;
172 self.check_mir_is_available(caller_body, &callsite.callee)?;
173 let callee_body = self.tcx.instance_mir(callsite.callee.def);
174 self.check_mir_body(callsite, callee_body, callee_attrs)?;
175
176 if !self.tcx.consider_optimizing(|| {
c295e0f8 177 format!("Inline {:?} into {:?}", callsite.callee, caller_body.source)
6a06907d
XL
178 }) {
179 return Err("optimization fuel exhausted");
180 }
8bb4bdeb 181
923072b8 182 let Ok(callee_body) = callsite.callee.try_subst_mir_and_normalize_erasing_regions(
6a06907d
XL
183 self.tcx,
184 self.param_env,
185 callee_body.clone(),
923072b8
FG
186 ) else {
187 return Err("failed to normalize callee body");
188 };
f9f354fc 189
064997fb
FG
190 // Check call signature compatibility.
191 // Normally, this shouldn't be required, but trait normalization failure can create a
192 // validation ICE.
193 let terminator = caller_body[callsite.block].terminator.as_ref().unwrap();
194 let TerminatorKind::Call { args, destination, .. } = &terminator.kind else { bug!() };
195 let destination_ty = destination.ty(&caller_body.local_decls, self.tcx).ty;
196 let output_type = callee_body.return_ty();
487cf647 197 if !util::is_subtype(self.tcx, self.param_env, output_type, destination_ty) {
064997fb
FG
198 trace!(?output_type, ?destination_ty);
199 return Err("failed to normalize return type");
200 }
201 if callsite.fn_sig.abi() == Abi::RustCall {
202 let (arg_tuple, skipped_args) = match &args[..] {
203 [arg_tuple] => (arg_tuple, 0),
204 [_, arg_tuple] => (arg_tuple, 1),
205 _ => bug!("Expected `rust-call` to have 1 or 2 args"),
206 };
207
208 let arg_tuple_ty = arg_tuple.ty(&caller_body.local_decls, self.tcx);
209 let ty::Tuple(arg_tuple_tys) = arg_tuple_ty.kind() else {
210 bug!("Closure arguments are not passed as a tuple");
211 };
212
213 for (arg_ty, input) in
214 arg_tuple_tys.iter().zip(callee_body.args_iter().skip(skipped_args))
215 {
216 let input_type = callee_body.local_decls[input].ty;
487cf647 217 if !util::is_subtype(self.tcx, self.param_env, input_type, arg_ty) {
064997fb
FG
218 trace!(?arg_ty, ?input_type);
219 return Err("failed to normalize tuple argument type");
220 }
221 }
222 } else {
223 for (arg, input) in args.iter().zip(callee_body.args_iter()) {
224 let input_type = callee_body.local_decls[input].ty;
225 let arg_ty = arg.ty(&caller_body.local_decls, self.tcx);
487cf647 226 if !util::is_subtype(self.tcx, self.param_env, input_type, arg_ty) {
064997fb
FG
227 trace!(?arg_ty, ?input_type);
228 return Err("failed to normalize argument type");
229 }
230 }
231 }
232
f2b60f7d 233 let old_blocks = caller_body.basic_blocks.next_index();
6a06907d 234 self.inline_call(caller_body, &callsite, callee_body);
f2b60f7d 235 let new_blocks = old_blocks..caller_body.basic_blocks.next_index();
8bb4bdeb 236
6a06907d
XL
237 Ok(new_blocks)
238 }
8bb4bdeb 239
6a06907d
XL
240 fn check_mir_is_available(
241 &self,
242 caller_body: &Body<'tcx>,
243 callee: &Instance<'tcx>,
244 ) -> Result<(), &'static str> {
5e7ed085
FG
245 let caller_def_id = caller_body.source.def_id();
246 let callee_def_id = callee.def_id();
247 if callee_def_id == caller_def_id {
6a06907d 248 return Err("self-recursion");
29967ef6 249 }
8bb4bdeb 250
5869c6ff
XL
251 match callee.def {
252 InstanceDef::Item(_) => {
253 // If there is no MIR available (either because it was not in metadata or
254 // because it has no MIR because it's an extern function), then the inliner
255 // won't cause cycles on this.
5e7ed085 256 if !self.tcx.is_mir_available(callee_def_id) {
6a06907d 257 return Err("item MIR unavailable");
5869c6ff 258 }
8bb4bdeb 259 }
5869c6ff 260 // These have no own callable MIR.
6a06907d
XL
261 InstanceDef::Intrinsic(_) | InstanceDef::Virtual(..) => {
262 return Err("instance without MIR (intrinsic / virtual)");
263 }
5869c6ff
XL
264 // This cannot result in an immediate cycle since the callee MIR is a shim, which does
265 // not get any optimizations run on it. Any subsequent inlining may cause cycles, but we
266 // do not need to catch this here, we can wait until the inliner decides to continue
267 // inlining a second time.
064997fb 268 InstanceDef::VTableShim(_)
5869c6ff
XL
269 | InstanceDef::ReifyShim(_)
270 | InstanceDef::FnPtrShim(..)
271 | InstanceDef::ClosureOnceShim { .. }
272 | InstanceDef::DropGlue(..)
6a06907d 273 | InstanceDef::CloneShim(..) => return Ok(()),
5869c6ff
XL
274 }
275
5e7ed085 276 if self.tcx.is_constructor(callee_def_id) {
5869c6ff
XL
277 trace!("constructors always have MIR");
278 // Constructor functions cannot cause a query cycle.
6a06907d 279 return Ok(());
8bb4bdeb
XL
280 }
281
5e7ed085 282 if callee_def_id.is_local() {
6a06907d 283 // Avoid a cycle here by only using `instance_mir` only if we have
5e7ed085
FG
284 // a lower `DefPathHash` than the callee. This ensures that the callee will
285 // not inline us. This trick even works with incremental compilation,
286 // since `DefPathHash` is stable.
287 if self.tcx.def_path_hash(caller_def_id).local_hash()
288 < self.tcx.def_path_hash(callee_def_id).local_hash()
a2a8927a 289 {
6a06907d
XL
290 return Ok(());
291 }
292
293 // If we know for sure that the function we're calling will itself try to
294 // call us, then we avoid inlining that function.
5e7ed085 295 if self.tcx.mir_callgraph_reachable((*callee, caller_def_id.expect_local())) {
6a06907d
XL
296 return Err("caller might be reachable from callee (query cycle avoidance)");
297 }
298
299 Ok(())
29967ef6 300 } else {
5869c6ff
XL
301 // This cannot result in an immediate cycle since the callee MIR is from another crate
302 // and is already optimized. Any subsequent inlining may cause cycles, but we do
303 // not need to catch this here, we can wait until the inliner decides to continue
304 // inlining a second time.
305 trace!("functions from other crates always have MIR");
6a06907d 306 Ok(())
8bb4bdeb 307 }
8bb4bdeb
XL
308 }
309
6a06907d 310 fn resolve_callsite(
dfeec247 311 &self,
6a06907d 312 caller_body: &Body<'tcx>,
dfeec247
XL
313 bb: BasicBlock,
314 bb_data: &BasicBlockData<'tcx>,
a1dfa0c6 315 ) -> Option<CallSite<'tcx>> {
a1dfa0c6
XL
316 // Only consider direct calls to functions
317 let terminator = bb_data.terminator();
9c376795 318 if let TerminatorKind::Call { ref func, target, fn_span, .. } = terminator.kind {
fc512014
XL
319 let func_ty = func.ty(caller_body, self.tcx);
320 if let ty::FnDef(def_id, substs) = *func_ty.kind() {
321 // To resolve an instance its substs have to be fully normalized.
923072b8 322 let substs = self.tcx.try_normalize_erasing_regions(self.param_env, substs).ok()?;
29967ef6 323 let callee =
fc512014 324 Instance::resolve(self.tcx, self.param_env, def_id, substs).ok().flatten()?;
29967ef6
XL
325
326 if let InstanceDef::Virtual(..) | InstanceDef::Intrinsic(_) = callee.def {
a1dfa0c6
XL
327 return None;
328 }
329
9c376795
FG
330 if self.history.contains(&callee.def_id()) {
331 return None;
332 }
333
04454e1e 334 let fn_sig = self.tcx.bound_fn_sig(def_id).subst(self.tcx, substs);
9c376795 335 let source_info = SourceInfo { span: fn_span, ..terminator.source_info };
fc512014 336
9c376795 337 return Some(CallSite { callee, fn_sig, block: bb, target, source_info });
a1dfa0c6
XL
338 }
339 }
340
341 None
342 }
343
6a06907d
XL
344 /// Returns an error if inlining is not possible based on codegen attributes alone. A success
345 /// indicates that inlining decision should be based on other criteria.
346 fn check_codegen_attributes(
347 &self,
348 callsite: &CallSite<'tcx>,
349 callee_attrs: &CodegenFnAttrs,
136023e0 350 ) -> Result<(), &'static str> {
064997fb
FG
351 match callee_attrs.inline {
352 InlineAttr::Never => return Err("never inline hint"),
353 InlineAttr::Always | InlineAttr::Hint => {}
354 InlineAttr::None => {
355 if self.tcx.sess.mir_opt_level() <= 2 {
356 return Err("at mir-opt-level=2, only #[inline] is inlined");
357 }
358 }
6a06907d 359 }
8bb4bdeb 360
6a06907d
XL
361 // Only inline local functions if they would be eligible for cross-crate
362 // inlining. This is to ensure that the final crate doesn't have MIR that
363 // reference unexported symbols
364 if callsite.callee.def_id().is_local() {
365 let is_generic = callsite.callee.substs.non_erasable_generics().next().is_some();
366 if !is_generic && !callee_attrs.requests_inline() {
367 return Err("not exported");
368 }
ea8adc8c 369 }
8bb4bdeb 370
6a06907d
XL
371 if callsite.fn_sig.c_variadic() {
372 return Err("C variadic");
373 }
60c5eb7d 374
6a06907d
XL
375 if callee_attrs.flags.contains(CodegenFnAttrFlags::COLD) {
376 return Err("cold");
74b04a01
XL
377 }
378
6a06907d
XL
379 if callee_attrs.no_sanitize != self.codegen_fn_attrs.no_sanitize {
380 return Err("incompatible sanitizer set");
5869c6ff
XL
381 }
382
487cf647
FG
383 // Two functions are compatible if the callee has no attribute (meaning
384 // that it's codegen agnostic), or sets an attribute that is identical
385 // to this function's attribute.
386 if callee_attrs.instruction_set.is_some()
387 && callee_attrs.instruction_set != self.codegen_fn_attrs.instruction_set
388 {
6a06907d
XL
389 return Err("incompatible instruction set");
390 }
8bb4bdeb 391
6a06907d
XL
392 for feature in &callee_attrs.target_features {
393 if !self.codegen_fn_attrs.target_features.contains(feature) {
394 return Err("incompatible target feature");
8bb4bdeb
XL
395 }
396 }
397
6a06907d
XL
398 Ok(())
399 }
8bb4bdeb 400
6a06907d
XL
401 /// Returns inlining decision that is based on the examination of callee MIR body.
402 /// Assumes that codegen attributes have been checked for compatibility already.
403 #[instrument(level = "debug", skip(self, callee_body))]
404 fn check_mir_body(
405 &self,
406 callsite: &CallSite<'tcx>,
407 callee_body: &Body<'tcx>,
408 callee_attrs: &CodegenFnAttrs,
409 ) -> Result<(), &'static str> {
410 let tcx = self.tcx;
fc512014 411
6a06907d 412 let mut threshold = if callee_attrs.requests_inline() {
064997fb 413 self.tcx.sess.opts.unstable_opts.inline_mir_hint_threshold.unwrap_or(100)
6a06907d 414 } else {
064997fb 415 self.tcx.sess.opts.unstable_opts.inline_mir_threshold.unwrap_or(50)
6a06907d 416 };
8bb4bdeb
XL
417
418 // Give a bonus functions with a small number of blocks,
419 // We normally have two or three blocks for even
420 // very small functions.
f2b60f7d 421 if callee_body.basic_blocks.len() <= 3 {
8bb4bdeb
XL
422 threshold += threshold / 4;
423 }
abe05a73 424 debug!(" final inline threshold = {}", threshold);
8bb4bdeb
XL
425
426 // FIXME: Give a bonus to functions with only a single caller
f2b60f7d
FG
427 let diverges = matches!(
428 callee_body.basic_blocks[START_BLOCK].terminator().kind,
429 TerminatorKind::Unreachable | TerminatorKind::Call { target: None, .. }
430 );
431 if diverges && !matches!(callee_attrs.inline, InlineAttr::Always) {
432 return Err("callee diverges unconditionally");
433 }
8bb4bdeb 434
f2b60f7d
FG
435 let mut checker = CostChecker {
436 tcx: self.tcx,
437 param_env: self.param_env,
438 instance: callsite.callee,
439 callee_body,
440 cost: 0,
441 validation: Ok(()),
442 };
443
444 // Traverse the MIR manually so we can account for the effects of inlining on the CFG.
8bb4bdeb 445 let mut work_list = vec![START_BLOCK];
f2b60f7d 446 let mut visited = BitSet::new_empty(callee_body.basic_blocks.len());
8bb4bdeb 447 while let Some(bb) = work_list.pop() {
dfeec247
XL
448 if !visited.insert(bb.index()) {
449 continue;
450 }
8bb4bdeb 451
f2b60f7d
FG
452 let blk = &callee_body.basic_blocks[bb];
453 checker.visit_basic_block_data(bb, blk);
8bb4bdeb 454
f2b60f7d
FG
455 let term = blk.terminator();
456 if let TerminatorKind::Drop { ref place, target, unwind }
457 | TerminatorKind::DropAndReplace { ref place, target, unwind, .. } = term.kind
458 {
459 work_list.push(target);
a2a8927a 460
f2b60f7d
FG
461 // If the place doesn't actually need dropping, treat it like a regular goto.
462 let ty = callsite.callee.subst_mir(self.tcx, &place.ty(callee_body, tcx).ty);
463 if ty.needs_drop(tcx, self.param_env) && let Some(unwind) = unwind {
464 work_list.push(unwind);
a2a8927a 465 }
487cf647
FG
466 } else if callee_attrs.instruction_set != self.codegen_fn_attrs.instruction_set
467 && matches!(term.kind, TerminatorKind::InlineAsm { .. })
468 {
469 // During the attribute checking stage we allow a callee with no
470 // instruction_set assigned to count as compatible with a function that does
471 // assign one. However, during this stage we require an exact match when any
472 // inline-asm is detected. LLVM will still possibly do an inline later on
473 // if the no-attribute function ends up with the same instruction set anyway.
474 return Err("Cannot move inline-asm across instruction sets");
f2b60f7d
FG
475 } else {
476 work_list.extend(term.successors())
8bb4bdeb 477 }
8bb4bdeb
XL
478 }
479
480 // Count up the cost of local variables and temps, if we know the size
481 // use that, otherwise we use a moderately-large dummy cost.
dc9dc135 482 for v in callee_body.vars_and_temps_iter() {
f2b60f7d 483 checker.visit_local_decl(v, &callee_body.local_decls[v]);
8bb4bdeb
XL
484 }
485
f2b60f7d
FG
486 // Abort if type validation found anything fishy.
487 checker.validation?;
488
489 let cost = checker.cost;
6a06907d 490 if let InlineAttr::Always = callee_attrs.inline {
abe05a73 491 debug!("INLINING {:?} because inline(always) [cost={}]", callsite, cost);
6a06907d 492 Ok(())
064997fb
FG
493 } else if cost <= threshold {
494 debug!("INLINING {:?} [cost={} <= threshold={}]", callsite, cost, threshold);
495 Ok(())
8bb4bdeb 496 } else {
064997fb
FG
497 debug!("NOT inlining {:?} [cost={} > threshold={}]", callsite, cost, threshold);
498 Err("cost above threshold")
8bb4bdeb
XL
499 }
500 }
501
dfeec247
XL
502 fn inline_call(
503 &self,
f9f354fc 504 caller_body: &mut Body<'tcx>,
6a06907d 505 callsite: &CallSite<'tcx>,
f9f354fc 506 mut callee_body: Body<'tcx>,
29967ef6
XL
507 ) {
508 let terminator = caller_body[callsite.block].terminator.take().unwrap();
8bb4bdeb 509 match terminator.kind {
29967ef6 510 TerminatorKind::Call { args, destination, cleanup, .. } => {
8bb4bdeb
XL
511 // If the call is something like `a[*i] = f(i)`, where
512 // `i : &mut usize`, then just duplicating the `a[*i]`
ff7c6d11 513 // Place could result in two different locations if `f`
8bb4bdeb 514 // writes to `i`. To prevent this we need to create a temporary
ff7c6d11 515 // borrow of the place and pass the destination as `*temp` instead.
ba9703b0 516 fn dest_needs_borrow(place: Place<'_>) -> bool {
e1599b0c
XL
517 for elem in place.projection.iter() {
518 match elem {
dfeec247 519 ProjectionElem::Deref | ProjectionElem::Index(_) => return true,
e1599b0c 520 _ => {}
8bb4bdeb 521 }
e1599b0c 522 }
dc9dc135 523
dfeec247 524 false
8bb4bdeb
XL
525 }
526
923072b8
FG
527 let dest = if dest_needs_borrow(destination) {
528 trace!("creating temp for return destination");
529 let dest = Rvalue::Ref(
530 self.tcx.lifetimes.re_erased,
531 BorrowKind::Mut { allow_two_phase_borrow: false },
532 destination,
533 );
534 let dest_ty = dest.ty(caller_body, self.tcx);
535 let temp = Place::from(self.new_call_temp(caller_body, &callsite, dest_ty));
536 caller_body[callsite.block].statements.push(Statement {
537 source_info: callsite.source_info,
538 kind: StatementKind::Assign(Box::new((temp, dest))),
539 });
540 self.tcx.mk_place_deref(temp)
8bb4bdeb 541 } else {
923072b8 542 destination
8bb4bdeb
XL
543 };
544
9c376795
FG
545 // Always create a local to hold the destination, as `RETURN_PLACE` may appear
546 // where a full `Place` is not allowed.
547 let (remap_destination, destination_local) = if let Some(d) = dest.as_local() {
548 (false, d)
549 } else {
550 (
551 true,
552 self.new_call_temp(
553 caller_body,
554 &callsite,
555 destination.ty(caller_body, self.tcx).ty,
556 ),
557 )
558 };
559
83c7162d 560 // Copy the arguments if needed.
fc512014 561 let args: Vec<_> = self.make_call_args(args, &callsite, caller_body, &callee_body);
8bb4bdeb 562
5e7ed085
FG
563 let mut expn_data = ExpnData::default(
564 ExpnKind::Inlined,
565 callsite.source_info.span,
566 self.tcx.sess.edition(),
567 None,
568 None,
569 );
570 expn_data.def_site = callee_body.span;
571 let expn_data =
064997fb 572 self.tcx.with_stable_hashing_context(|hcx| LocalExpnId::fresh(expn_data, hcx));
8bb4bdeb 573 let mut integrator = Integrator {
8bb4bdeb 574 args: &args,
29967ef6
XL
575 new_locals: Local::new(caller_body.local_decls.len())..,
576 new_scopes: SourceScope::new(caller_body.source_scopes.len())..,
f2b60f7d 577 new_blocks: BasicBlock::new(caller_body.basic_blocks.len())..,
9c376795 578 destination: destination_local,
923072b8
FG
579 callsite_scope: caller_body.source_scopes[callsite.source_info.scope].clone(),
580 callsite,
8bb4bdeb 581 cleanup_block: cleanup,
e1599b0c 582 in_cleanup_block: false,
e74abb32 583 tcx: self.tcx,
5e7ed085 584 expn_data,
fc512014 585 always_live_locals: BitSet::new_filled(callee_body.local_decls.len()),
8bb4bdeb
XL
586 };
587
29967ef6
XL
588 // Map all `Local`s, `SourceScope`s and `BasicBlock`s to new ones
589 // (or existing ones, in a few special cases) in the caller.
590 integrator.visit_body(&mut callee_body);
8bb4bdeb 591
fc512014
XL
592 // If there are any locals without storage markers, give them storage only for the
593 // duration of the call.
594 for local in callee_body.vars_and_temps_iter() {
f2b60f7d
FG
595 if !callee_body.local_decls[local].internal
596 && integrator.always_live_locals.contains(local)
597 {
fc512014
XL
598 let new_local = integrator.map_local(local);
599 caller_body[callsite.block].statements.push(Statement {
600 source_info: callsite.source_info,
601 kind: StatementKind::StorageLive(new_local),
602 });
603 }
604 }
605 if let Some(block) = callsite.target {
606 // To avoid repeated O(n) insert, push any new statements to the end and rotate
607 // the slice once.
608 let mut n = 0;
9c376795
FG
609 if remap_destination {
610 caller_body[block].statements.push(Statement {
611 source_info: callsite.source_info,
612 kind: StatementKind::Assign(Box::new((
613 dest,
614 Rvalue::Use(Operand::Move(destination_local.into())),
615 ))),
616 });
617 n += 1;
618 }
fc512014 619 for local in callee_body.vars_and_temps_iter().rev() {
f2b60f7d
FG
620 if !callee_body.local_decls[local].internal
621 && integrator.always_live_locals.contains(local)
622 {
fc512014
XL
623 let new_local = integrator.map_local(local);
624 caller_body[block].statements.push(Statement {
625 source_info: callsite.source_info,
626 kind: StatementKind::StorageDead(new_local),
627 });
628 n += 1;
629 }
630 }
631 caller_body[block].statements.rotate_right(n);
632 }
633
29967ef6 634 // Insert all of the (mapped) parts of the callee body into the caller.
94222f64
XL
635 caller_body.local_decls.extend(callee_body.drain_vars_and_temps());
636 caller_body.source_scopes.extend(&mut callee_body.source_scopes.drain(..));
637 caller_body.var_debug_info.append(&mut callee_body.var_debug_info);
29967ef6 638 caller_body.basic_blocks_mut().extend(callee_body.basic_blocks_mut().drain(..));
8bb4bdeb 639
29967ef6
XL
640 caller_body[callsite.block].terminator = Some(Terminator {
641 source_info: callsite.source_info,
642 kind: TerminatorKind::Goto { target: integrator.map_block(START_BLOCK) },
643 });
8bb4bdeb 644
29967ef6
XL
645 // Copy only unevaluated constants from the callee_body into the caller_body.
646 // Although we are only pushing `ConstKind::Unevaluated` consts to
647 // `required_consts`, here we may not only have `ConstKind::Unevaluated`
648 // because we are calling `subst_and_normalize_erasing_regions`.
649 caller_body.required_consts.extend(
f2b60f7d
FG
650 callee_body.required_consts.iter().copied().filter(|&ct| match ct.literal {
651 ConstantKind::Ty(_) => {
2b03887a 652 bug!("should never encounter ty::UnevaluatedConst in `required_consts`")
6a06907d 653 }
f2b60f7d 654 ConstantKind::Val(..) | ConstantKind::Unevaluated(..) => true,
29967ef6
XL
655 }),
656 );
8bb4bdeb 657 }
29967ef6 658 kind => bug!("unexpected terminator kind {:?}", kind),
8bb4bdeb
XL
659 }
660 }
661
abe05a73
XL
662 fn make_call_args(
663 &self,
664 args: Vec<Operand<'tcx>>,
665 callsite: &CallSite<'tcx>,
f9f354fc 666 caller_body: &mut Body<'tcx>,
fc512014 667 callee_body: &Body<'tcx>,
ff7c6d11 668 ) -> Vec<Local> {
8bb4bdeb 669 let tcx = self.tcx;
abe05a73 670
ff7c6d11
XL
671 // There is a bit of a mismatch between the *caller* of a closure and the *callee*.
672 // The caller provides the arguments wrapped up in a tuple:
673 //
674 // tuple_tmp = (a, b, c)
675 // Fn::call(closure_ref, tuple_tmp)
676 //
677 // meanwhile the closure body expects the arguments (here, `a`, `b`, and `c`)
94b46f34
XL
678 // as distinct arguments. (This is the "rust-call" ABI hack.) Normally, codegen has
679 // the job of unpacking this tuple. But here, we are codegen. =) So we want to create
ff7c6d11
XL
680 // a vector like
681 //
682 // [closure_ref, tuple_tmp.0, tuple_tmp.1, tuple_tmp.2]
683 //
684 // Except for one tiny wrinkle: we don't actually want `tuple_tmp.0`. It's more convenient
685 // if we "spill" that into *another* temporary, so that we can map the argument
686 // variable in the callee MIR directly to an argument variable on our side.
687 // So we introduce temporaries like:
688 //
689 // tmp0 = tuple_tmp.0
690 // tmp1 = tuple_tmp.1
691 // tmp2 = tuple_tmp.2
692 //
693 // and the vector is `[closure_ref, tmp0, tmp1, tmp2]`.
fc512014 694 if callsite.fn_sig.abi() == Abi::RustCall && callee_body.spread_arg.is_none() {
abe05a73 695 let mut args = args.into_iter();
29967ef6
XL
696 let self_ = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body);
697 let tuple = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body);
abe05a73
XL
698 assert!(args.next().is_none());
699
dc9dc135 700 let tuple = Place::from(tuple);
3c0e092e 701 let ty::Tuple(tuple_tys) = tuple.ty(caller_body, tcx).ty.kind() else {
abe05a73
XL
702 bug!("Closure arguments are not passed as a tuple");
703 };
704
ff7c6d11
XL
705 // The `closure_ref` in our example above.
706 let closure_ref_arg = iter::once(self_);
707
5e7ed085 708 // The `tmp0`, `tmp1`, and `tmp2` in our example above.
dfeec247
XL
709 let tuple_tmp_args = tuple_tys.iter().enumerate().map(|(i, ty)| {
710 // This is e.g., `tuple_tmp.0` in our example above.
5e7ed085 711 let tuple_field = Operand::Move(tcx.mk_place_field(tuple, Field::new(i), ty));
dfeec247
XL
712
713 // Spill to a local to make e.g., `tmp0`.
29967ef6 714 self.create_temp_if_necessary(tuple_field, callsite, caller_body)
dfeec247 715 });
ff7c6d11
XL
716
717 closure_ref_arg.chain(tuple_tmp_args).collect()
abe05a73
XL
718 } else {
719 args.into_iter()
29967ef6 720 .map(|a| self.create_temp_if_necessary(a, callsite, caller_body))
abe05a73
XL
721 .collect()
722 }
723 }
724
725 /// If `arg` is already a temporary, returns it. Otherwise, introduces a fresh
726 /// temporary `T` and an instruction `T = arg`, and returns `T`.
727 fn create_temp_if_necessary(
728 &self,
729 arg: Operand<'tcx>,
730 callsite: &CallSite<'tcx>,
f9f354fc 731 caller_body: &mut Body<'tcx>,
ff7c6d11 732 ) -> Local {
29967ef6 733 // Reuse the operand if it is a moved temporary.
5e7ed085
FG
734 if let Operand::Move(place) = &arg
735 && let Some(local) = place.as_local()
736 && caller_body.local_kind(local) == LocalKind::Temp
737 {
738 return local;
abe05a73 739 }
8bb4bdeb 740
29967ef6
XL
741 // Otherwise, create a temporary for the argument.
742 trace!("creating temp for argument {:?}", arg);
743 let arg_ty = arg.ty(caller_body, self.tcx);
744 let local = self.new_call_temp(caller_body, callsite, arg_ty);
745 caller_body[callsite.block].statements.push(Statement {
746 source_info: callsite.source_info,
94222f64 747 kind: StatementKind::Assign(Box::new((Place::from(local), Rvalue::Use(arg)))),
29967ef6
XL
748 });
749 local
750 }
8bb4bdeb 751
29967ef6
XL
752 /// Introduces a new temporary into the caller body that is live for the duration of the call.
753 fn new_call_temp(
754 &self,
755 caller_body: &mut Body<'tcx>,
756 callsite: &CallSite<'tcx>,
757 ty: Ty<'tcx>,
758 ) -> Local {
759 let local = caller_body.local_decls.push(LocalDecl::new(ty, callsite.source_info.span));
8bb4bdeb 760
29967ef6
XL
761 caller_body[callsite.block].statements.push(Statement {
762 source_info: callsite.source_info,
763 kind: StatementKind::StorageLive(local),
1b1a35ee 764 });
1b1a35ee 765
29967ef6
XL
766 if let Some(block) = callsite.target {
767 caller_body[block].statements.insert(
768 0,
769 Statement {
770 source_info: callsite.source_info,
771 kind: StatementKind::StorageDead(local),
772 },
773 );
774 }
775
776 local
8bb4bdeb
XL
777 }
778}
779
dc9dc135
XL
780fn type_size_of<'tcx>(
781 tcx: TyCtxt<'tcx>,
782 param_env: ty::ParamEnv<'tcx>,
783 ty: Ty<'tcx>,
784) -> Option<u64> {
2c00a5a8 785 tcx.layout_of(param_env.and(ty)).ok().map(|layout| layout.size.bytes())
8bb4bdeb
XL
786}
787
f2b60f7d
FG
788/// Verify that the callee body is compatible with the caller.
789///
790/// This visitor mostly computes the inlining cost,
791/// but also needs to verify that types match because of normalization failure.
792struct CostChecker<'b, 'tcx> {
793 tcx: TyCtxt<'tcx>,
794 param_env: ParamEnv<'tcx>,
795 cost: usize,
796 callee_body: &'b Body<'tcx>,
797 instance: ty::Instance<'tcx>,
798 validation: Result<(), &'static str>,
799}
800
801impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> {
802 fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
803 // Don't count StorageLive/StorageDead in the inlining cost.
804 match statement.kind {
805 StatementKind::StorageLive(_)
806 | StatementKind::StorageDead(_)
807 | StatementKind::Deinit(_)
808 | StatementKind::Nop => {}
809 _ => self.cost += INSTR_COST,
810 }
811
812 self.super_statement(statement, location);
813 }
814
815 fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
816 let tcx = self.tcx;
817 match terminator.kind {
818 TerminatorKind::Drop { ref place, unwind, .. }
819 | TerminatorKind::DropAndReplace { ref place, unwind, .. } => {
820 // If the place doesn't actually need dropping, treat it like a regular goto.
821 let ty = self.instance.subst_mir(tcx, &place.ty(self.callee_body, tcx).ty);
822 if ty.needs_drop(tcx, self.param_env) {
823 self.cost += CALL_PENALTY;
824 if unwind.is_some() {
825 self.cost += LANDINGPAD_PENALTY;
826 }
827 } else {
828 self.cost += INSTR_COST;
829 }
830 }
831 TerminatorKind::Call { func: Operand::Constant(ref f), cleanup, .. } => {
832 let fn_ty = self.instance.subst_mir(tcx, &f.literal.ty());
833 self.cost += if let ty::FnDef(def_id, _) = *fn_ty.kind() && tcx.is_intrinsic(def_id) {
834 // Don't give intrinsics the extra penalty for calls
835 INSTR_COST
836 } else {
837 CALL_PENALTY
838 };
839 if cleanup.is_some() {
840 self.cost += LANDINGPAD_PENALTY;
841 }
842 }
843 TerminatorKind::Assert { cleanup, .. } => {
844 self.cost += CALL_PENALTY;
845 if cleanup.is_some() {
846 self.cost += LANDINGPAD_PENALTY;
847 }
848 }
849 TerminatorKind::Resume => self.cost += RESUME_PENALTY,
850 TerminatorKind::InlineAsm { cleanup, .. } => {
851 self.cost += INSTR_COST;
852 if cleanup.is_some() {
853 self.cost += LANDINGPAD_PENALTY;
854 }
855 }
856 _ => self.cost += INSTR_COST,
857 }
858
859 self.super_terminator(terminator, location);
860 }
861
862 /// Count up the cost of local variables and temps, if we know the size
863 /// use that, otherwise we use a moderately-large dummy cost.
864 fn visit_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>) {
865 let tcx = self.tcx;
866 let ptr_size = tcx.data_layout.pointer_size.bytes();
867
868 let ty = self.instance.subst_mir(tcx, &local_decl.ty);
869 // Cost of the var is the size in machine-words, if we know
870 // it.
871 if let Some(size) = type_size_of(tcx, self.param_env, ty) {
872 self.cost += ((size + ptr_size - 1) / ptr_size) as usize;
873 } else {
874 self.cost += UNKNOWN_SIZE_COST;
875 }
876
877 self.super_local_decl(local, local_decl)
878 }
879
880 /// This method duplicates code from MIR validation in an attempt to detect type mismatches due
881 /// to normalization failure.
882 fn visit_projection_elem(
883 &mut self,
884 local: Local,
885 proj_base: &[PlaceElem<'tcx>],
886 elem: PlaceElem<'tcx>,
887 context: PlaceContext,
888 location: Location,
889 ) {
890 if let ProjectionElem::Field(f, ty) = elem {
891 let parent = Place { local, projection: self.tcx.intern_place_elems(proj_base) };
892 let parent_ty = parent.ty(&self.callee_body.local_decls, self.tcx);
893 let check_equal = |this: &mut Self, f_ty| {
487cf647 894 if !util::is_equal_up_to_subtyping(this.tcx, this.param_env, ty, f_ty) {
f2b60f7d
FG
895 trace!(?ty, ?f_ty);
896 this.validation = Err("failed to normalize projection type");
897 return;
898 }
899 };
900
901 let kind = match parent_ty.ty.kind() {
9c376795 902 &ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
f2b60f7d
FG
903 self.tcx.bound_type_of(def_id).subst(self.tcx, substs).kind()
904 }
905 kind => kind,
906 };
907
908 match kind {
909 ty::Tuple(fields) => {
910 let Some(f_ty) = fields.get(f.as_usize()) else {
911 self.validation = Err("malformed MIR");
912 return;
913 };
914 check_equal(self, *f_ty);
915 }
916 ty::Adt(adt_def, substs) => {
917 let var = parent_ty.variant_index.unwrap_or(VariantIdx::from_u32(0));
918 let Some(field) = adt_def.variant(var).fields.get(f.as_usize()) else {
919 self.validation = Err("malformed MIR");
920 return;
921 };
922 check_equal(self, field.ty(self.tcx, substs));
923 }
924 ty::Closure(_, substs) => {
925 let substs = substs.as_closure();
926 let Some(f_ty) = substs.upvar_tys().nth(f.as_usize()) else {
927 self.validation = Err("malformed MIR");
928 return;
929 };
930 check_equal(self, f_ty);
931 }
932 &ty::Generator(def_id, substs, _) => {
933 let f_ty = if let Some(var) = parent_ty.variant_index {
934 let gen_body = if def_id == self.callee_body.source.def_id() {
935 self.callee_body
936 } else {
937 self.tcx.optimized_mir(def_id)
938 };
939
940 let Some(layout) = gen_body.generator_layout() else {
941 self.validation = Err("malformed MIR");
942 return;
943 };
944
945 let Some(&local) = layout.variant_fields[var].get(f) else {
946 self.validation = Err("malformed MIR");
947 return;
948 };
949
950 let Some(&f_ty) = layout.field_tys.get(local) else {
951 self.validation = Err("malformed MIR");
952 return;
953 };
954
955 f_ty
956 } else {
957 let Some(f_ty) = substs.as_generator().prefix_tys().nth(f.index()) else {
958 self.validation = Err("malformed MIR");
959 return;
960 };
961
962 f_ty
963 };
964
965 check_equal(self, f_ty);
966 }
967 _ => self.validation = Err("malformed MIR"),
968 }
969 }
970
971 self.super_projection_elem(local, proj_base, elem, context, location);
972 }
973}
974
8bb4bdeb
XL
975/**
976 * Integrator.
977 *
978 * Integrates blocks from the callee function into the calling function.
979 * Updates block indices, references to locals and other control flow
980 * stuff.
dc9dc135
XL
981*/
982struct Integrator<'a, 'tcx> {
ff7c6d11 983 args: &'a [Local],
29967ef6
XL
984 new_locals: RangeFrom<Local>,
985 new_scopes: RangeFrom<SourceScope>,
986 new_blocks: RangeFrom<BasicBlock>,
9c376795 987 destination: Local,
923072b8
FG
988 callsite_scope: SourceScopeData<'tcx>,
989 callsite: &'a CallSite<'tcx>,
8bb4bdeb
XL
990 cleanup_block: Option<BasicBlock>,
991 in_cleanup_block: bool,
e74abb32 992 tcx: TyCtxt<'tcx>,
5e7ed085 993 expn_data: LocalExpnId,
fc512014 994 always_live_locals: BitSet<Local>,
8bb4bdeb
XL
995}
996
a2a8927a 997impl Integrator<'_, '_> {
29967ef6
XL
998 fn map_local(&self, local: Local) -> Local {
999 let new = if local == RETURN_PLACE {
9c376795 1000 self.destination
29967ef6
XL
1001 } else {
1002 let idx = local.index() - 1;
1003 if idx < self.args.len() {
1004 self.args[idx]
1005 } else {
1006 Local::new(self.new_locals.start.index() + (idx - self.args.len()))
1007 }
1008 };
1009 trace!("mapping local `{:?}` to `{:?}`", local, new);
8bb4bdeb
XL
1010 new
1011 }
8bb4bdeb 1012
29967ef6
XL
1013 fn map_scope(&self, scope: SourceScope) -> SourceScope {
1014 let new = SourceScope::new(self.new_scopes.start.index() + scope.index());
1015 trace!("mapping scope `{:?}` to `{:?}`", scope, new);
1016 new
1017 }
e74abb32 1018
29967ef6
XL
1019 fn map_block(&self, block: BasicBlock) -> BasicBlock {
1020 let new = BasicBlock::new(self.new_blocks.start.index() + block.index());
1021 trace!("mapping block `{:?}` to `{:?}`", block, new);
1022 new
e74abb32 1023 }
2b03887a
FG
1024
1025 fn map_unwind(&self, unwind: Option<BasicBlock>) -> Option<BasicBlock> {
1026 if self.in_cleanup_block {
1027 if unwind.is_some() {
1028 bug!("cleanup on cleanup block");
1029 }
1030 return unwind;
1031 }
1032
1033 match unwind {
1034 Some(target) => Some(self.map_block(target)),
1035 // Add an unwind edge to the original call's cleanup block
1036 None => self.cleanup_block,
1037 }
1038 }
e74abb32
XL
1039}
1040
a2a8927a 1041impl<'tcx> MutVisitor<'tcx> for Integrator<'_, 'tcx> {
e74abb32
XL
1042 fn tcx(&self) -> TyCtxt<'tcx> {
1043 self.tcx
ea8adc8c
XL
1044 }
1045
dfeec247 1046 fn visit_local(&mut self, local: &mut Local, _ctxt: PlaceContext, _location: Location) {
29967ef6
XL
1047 *local = self.map_local(*local);
1048 }
1049
923072b8
FG
1050 fn visit_source_scope_data(&mut self, scope_data: &mut SourceScopeData<'tcx>) {
1051 self.super_source_scope_data(scope_data);
1052 if scope_data.parent_scope.is_none() {
1053 // Attach the outermost callee scope as a child of the callsite
1054 // scope, via the `parent_scope` and `inlined_parent_scope` chains.
1055 scope_data.parent_scope = Some(self.callsite.source_info.scope);
1056 assert_eq!(scope_data.inlined_parent_scope, None);
1057 scope_data.inlined_parent_scope = if self.callsite_scope.inlined.is_some() {
1058 Some(self.callsite.source_info.scope)
1059 } else {
1060 self.callsite_scope.inlined_parent_scope
1061 };
1062
1063 // Mark the outermost callee scope as an inlined one.
1064 assert_eq!(scope_data.inlined, None);
1065 scope_data.inlined = Some((self.callsite.callee, self.callsite.source_info.span));
1066 } else if scope_data.inlined_parent_scope.is_none() {
1067 // Make it easy to find the scope with `inlined` set above.
1068 scope_data.inlined_parent_scope = Some(self.map_scope(OUTERMOST_SOURCE_SCOPE));
1069 }
1070 }
1071
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1072 fn visit_source_scope(&mut self, scope: &mut SourceScope) {
1073 *scope = self.map_scope(*scope);
1074 }
1075
1076 fn visit_span(&mut self, span: &mut Span) {
1077 // Make sure that all spans track the fact that they were inlined.
5e7ed085 1078 *span = span.fresh_expansion(self.expn_data);
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1079 }
1080
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1081 fn visit_basic_block_data(&mut self, block: BasicBlock, data: &mut BasicBlockData<'tcx>) {
1082 self.in_cleanup_block = data.is_cleanup;
1083 self.super_basic_block_data(block, data);
1084 self.in_cleanup_block = false;
1085 }
1086
dfeec247 1087 fn visit_retag(&mut self, kind: &mut RetagKind, place: &mut Place<'tcx>, loc: Location) {
0731742a 1088 self.super_retag(kind, place, loc);
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1089
1090 // We have to patch all inlined retags to be aware that they are no longer
1091 // happening on function entry.
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1092 if *kind == RetagKind::FnEntry {
1093 *kind = RetagKind::Default;
1094 }
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1095 }
1096
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1097 fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
1098 if let StatementKind::StorageLive(local) | StatementKind::StorageDead(local) =
1099 statement.kind
1100 {
1101 self.always_live_locals.remove(local);
1102 }
1103 self.super_statement(statement, location);
1104 }
1105
f035d41b 1106 fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, loc: Location) {
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1107 // Don't try to modify the implicit `_0` access on return (`return` terminators are
1108 // replaced down below anyways).
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1109 if !matches!(terminator.kind, TerminatorKind::Return) {
1110 self.super_terminator(terminator, loc);
f9f354fc 1111 }
8bb4bdeb 1112
f035d41b 1113 match terminator.kind {
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1114 TerminatorKind::GeneratorDrop | TerminatorKind::Yield { .. } => bug!(),
1115 TerminatorKind::Goto { ref mut target } => {
29967ef6 1116 *target = self.map_block(*target);
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1117 }
1118 TerminatorKind::SwitchInt { ref mut targets, .. } => {
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1119 for tgt in targets.all_targets_mut() {
1120 *tgt = self.map_block(*tgt);
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1121 }
1122 }
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1123 TerminatorKind::Drop { ref mut target, ref mut unwind, .. }
1124 | TerminatorKind::DropAndReplace { ref mut target, ref mut unwind, .. } => {
29967ef6 1125 *target = self.map_block(*target);
2b03887a 1126 *unwind = self.map_unwind(*unwind);
8bb4bdeb 1127 }
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1128 TerminatorKind::Call { ref mut target, ref mut cleanup, .. } => {
1129 if let Some(ref mut tgt) = *target {
29967ef6 1130 *tgt = self.map_block(*tgt);
8bb4bdeb 1131 }
2b03887a 1132 *cleanup = self.map_unwind(*cleanup);
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1133 }
1134 TerminatorKind::Assert { ref mut target, ref mut cleanup, .. } => {
29967ef6 1135 *target = self.map_block(*target);
2b03887a 1136 *cleanup = self.map_unwind(*cleanup);
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1137 }
1138 TerminatorKind::Return => {
923072b8 1139 terminator.kind = if let Some(tgt) = self.callsite.target {
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1140 TerminatorKind::Goto { target: tgt }
1141 } else {
1142 TerminatorKind::Unreachable
1143 }
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1144 }
1145 TerminatorKind::Resume => {
1146 if let Some(tgt) = self.cleanup_block {
f035d41b 1147 terminator.kind = TerminatorKind::Goto { target: tgt }
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1148 }
1149 }
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1150 TerminatorKind::Abort => {}
1151 TerminatorKind::Unreachable => {}
f035d41b 1152 TerminatorKind::FalseEdge { ref mut real_target, ref mut imaginary_target } => {
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1153 *real_target = self.map_block(*real_target);
1154 *imaginary_target = self.map_block(*imaginary_target);
abe05a73 1155 }
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1156 TerminatorKind::FalseUnwind { real_target: _, unwind: _ } =>
1157 // see the ordering of passes in the optimized_mir query.
1158 {
2c00a5a8 1159 bug!("False unwinds should have been removed before inlining")
dfeec247 1160 }
a2a8927a 1161 TerminatorKind::InlineAsm { ref mut destination, ref mut cleanup, .. } => {
f9f354fc 1162 if let Some(ref mut tgt) = *destination {
29967ef6 1163 *tgt = self.map_block(*tgt);
f9f354fc 1164 }
2b03887a 1165 *cleanup = self.map_unwind(*cleanup);
f9f354fc 1166 }
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1167 }
1168 }
8bb4bdeb 1169}