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JakobDegenJakobDegen
committed
Disable top-down inlining
1 parent 744a97b commit f4f7777

10 files changed

+243
-115
lines changed

‎compiler/rustc_mir_transform/src/inline.rs

+6-22
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,6 @@ use rustc_middle::mir::visit::*;
88
use rustc_middle::mir::*;
99
use rustc_middle::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
1010
use rustc_session::config::OptLevel;
11-
use rustc_span::def_id::DefId;
1211
use rustc_span::{hygiene::ExpnKind, ExpnData, LocalExpnId, Span};
1312
use rustc_target::abi::VariantIdx;
1413
use rustc_target::spec::abi::Abi;
@@ -87,13 +86,8 @@ fn inline<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool {
8786

8887
let param_env = tcx.param_env_reveal_all_normalized(def_id);
8988

90-
let mut this = Inliner {
91-
tcx,
92-
param_env,
93-
codegen_fn_attrs: tcx.codegen_fn_attrs(def_id),
94-
history: Vec::new(),
95-
changed: false,
96-
};
89+
let mut this =
90+
Inliner { tcx, param_env, codegen_fn_attrs: tcx.codegen_fn_attrs(def_id), changed: false };
9791
let blocks = BasicBlock::new(0)..body.basic_blocks.next_index();
9892
this.process_blocks(body, blocks);
9993
this.changed
@@ -104,12 +98,6 @@ struct Inliner<'tcx> {
10498
param_env: ParamEnv<'tcx>,
10599
/// Caller codegen attributes.
106100
codegen_fn_attrs: &'tcx CodegenFnAttrs,
107-
/// Stack of inlined instances.
108-
/// We only check the `DefId` and not the substs because we want to
109-
/// avoid inlining cases of polymorphic recursion.
110-
/// The number of `DefId`s is finite, so checking history is enough
111-
/// to ensure that we do not loop endlessly while inlining.
112-
history: Vec<DefId>,
113101
/// Indicates that the caller body has been modified.
114102
changed: bool,
115103
}
@@ -134,12 +122,12 @@ impl<'tcx> Inliner<'tcx> {
134122
debug!("not-inlined {} [{}]", callsite.callee, reason);
135123
continue;
136124
}
137-
Ok(new_blocks) => {
125+
Ok(_) => {
138126
debug!("inlined {}", callsite.callee);
139127
self.changed = true;
140-
self.history.push(callsite.callee.def_id());
141-
self.process_blocks(caller_body, new_blocks);
142-
self.history.pop();
128+
// We could process the blocks returned by `try_inlining` here. However, that
129+
// leads to exponential compile times due to the top-down nature of this kind
130+
// of inlining.
143131
}
144132
}
145133
}
@@ -313,10 +301,6 @@ impl<'tcx> Inliner<'tcx> {
313301
return None;
314302
}
315303

316-
if self.history.contains(&callee.def_id()) {
317-
return None;
318-
}
319-
320304
let fn_sig = self.tcx.bound_fn_sig(def_id).subst(self.tcx, substs);
321305

322306
return Some(CallSite {

‎src/test/mir-opt/inline/cycle.g.Inline.diff

+12-11
Original file line numberDiff line numberDiff line change
@@ -10,8 +10,6 @@
1010
+ let _3: (); // in scope 1 at $DIR/cycle.rs:6:5: 6:8
1111
+ let mut _4: &fn() {main}; // in scope 1 at $DIR/cycle.rs:6:5: 6:6
1212
+ let mut _5: (); // in scope 1 at $DIR/cycle.rs:6:5: 6:8
13-
+ scope 2 (inlined <fn() {main} as Fn<()>>::call - shim(fn() {main})) { // at $DIR/cycle.rs:6:5: 6:8
14-
+ }
1513
+ }
1614

1715
bb0: {
@@ -29,7 +27,10 @@
2927
+ StorageLive(_4); // scope 1 at $DIR/cycle.rs:6:5: 6:6
3028
+ _4 = &_2; // scope 1 at $DIR/cycle.rs:6:5: 6:6
3129
+ StorageLive(_5); // scope 1 at $DIR/cycle.rs:6:5: 6:8
32-
+ _3 = move (*_4)() -> [return: bb4, unwind: bb2]; // scope 2 at $SRC_DIR/core/src/ops/function.rs:LL:COL
30+
+ _3 = <fn() {main} as Fn<()>>::call(move _4, move _5) -> [return: bb2, unwind: bb3]; // scope 1 at $DIR/cycle.rs:6:5: 6:8
31+
+ // mir::Constant
32+
+ // + span: $DIR/cycle.rs:6:5: 6:6
33+
+ // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a fn() {main}, ()) -> <fn() {main} as FnOnce<()>>::Output {<fn() {main} as Fn<()>>::call}, val: Value(<ZST>) }
3334
}
3435

3536
bb1: {
@@ -39,19 +40,19 @@
3940
return; // scope 0 at $DIR/cycle.rs:+2:2: +2:2
4041
+ }
4142
+
42-
+ bb2 (cleanup): {
43-
+ drop(_2) -> bb3; // scope 1 at $DIR/cycle.rs:7:1: 7:2
43+
+ bb2: {
44+
+ StorageDead(_5); // scope 1 at $DIR/cycle.rs:6:7: 6:8
45+
+ StorageDead(_4); // scope 1 at $DIR/cycle.rs:6:7: 6:8
46+
+ StorageDead(_3); // scope 1 at $DIR/cycle.rs:6:8: 6:9
47+
+ drop(_2) -> bb1; // scope 1 at $DIR/cycle.rs:7:1: 7:2
4448
+ }
4549
+
4650
+ bb3 (cleanup): {
47-
+ resume; // scope 1 at $DIR/cycle.rs:5:1: 7:2
51+
+ drop(_2) -> bb4; // scope 1 at $DIR/cycle.rs:7:1: 7:2
4852
+ }
4953
+
50-
+ bb4: {
51-
+ StorageDead(_5); // scope 1 at $DIR/cycle.rs:6:7: 6:8
52-
+ StorageDead(_4); // scope 1 at $DIR/cycle.rs:6:7: 6:8
53-
+ StorageDead(_3); // scope 1 at $DIR/cycle.rs:6:8: 6:9
54-
+ drop(_2) -> bb1; // scope 1 at $DIR/cycle.rs:7:1: 7:2
54+
+ bb4 (cleanup): {
55+
+ resume; // scope 1 at $DIR/cycle.rs:5:1: 7:2
5556
}
5657
}
5758

‎src/test/mir-opt/inline/cycle.main.Inline.diff

+12-28
Original file line numberDiff line numberDiff line change
@@ -10,18 +10,6 @@
1010
+ let _3: (); // in scope 1 at $DIR/cycle.rs:6:5: 6:8
1111
+ let mut _4: &fn() {g}; // in scope 1 at $DIR/cycle.rs:6:5: 6:6
1212
+ let mut _5: (); // in scope 1 at $DIR/cycle.rs:6:5: 6:8
13-
+ scope 2 (inlined <fn() {g} as Fn<()>>::call - shim(fn() {g})) { // at $DIR/cycle.rs:6:5: 6:8
14-
+ scope 3 (inlined g) { // at $SRC_DIR/core/src/ops/function.rs:LL:COL
15-
+ let mut _6: fn() {main}; // in scope 3 at $DIR/cycle.rs:12:5: 12:12
16-
+ scope 4 (inlined f::<fn() {main}>) { // at $DIR/cycle.rs:12:5: 12:12
17-
+ debug g => _6; // in scope 4 at $DIR/cycle.rs:5:6: 5:7
18-
+ let _7: (); // in scope 4 at $DIR/cycle.rs:6:5: 6:8
19-
+ let mut _8: &fn() {main}; // in scope 4 at $DIR/cycle.rs:6:5: 6:6
20-
+ scope 5 (inlined <fn() {main} as Fn<()>>::call - shim(fn() {main})) { // at $DIR/cycle.rs:6:5: 6:8
21-
+ }
22-
+ }
23-
+ }
24-
+ }
2513
+ }
2614

2715
bb0: {
@@ -39,11 +27,10 @@
3927
+ StorageLive(_4); // scope 1 at $DIR/cycle.rs:6:5: 6:6
4028
+ _4 = &_2; // scope 1 at $DIR/cycle.rs:6:5: 6:6
4129
+ StorageLive(_5); // scope 1 at $DIR/cycle.rs:6:5: 6:8
42-
+ StorageLive(_6); // scope 3 at $DIR/cycle.rs:12:5: 12:12
43-
+ StorageLive(_7); // scope 4 at $DIR/cycle.rs:6:5: 6:8
44-
+ StorageLive(_8); // scope 4 at $DIR/cycle.rs:6:5: 6:6
45-
+ _8 = &_6; // scope 4 at $DIR/cycle.rs:6:5: 6:6
46-
+ _7 = move (*_8)() -> [return: bb4, unwind: bb2]; // scope 5 at $SRC_DIR/core/src/ops/function.rs:LL:COL
30+
+ _3 = <fn() {g} as Fn<()>>::call(move _4, move _5) -> [return: bb2, unwind: bb3]; // scope 1 at $DIR/cycle.rs:6:5: 6:8
31+
+ // mir::Constant
32+
+ // + span: $DIR/cycle.rs:6:5: 6:6
33+
+ // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a fn() {g}, ()) -> <fn() {g} as FnOnce<()>>::Output {<fn() {g} as Fn<()>>::call}, val: Value(<ZST>) }
4734
}
4835

4936
bb1: {
@@ -53,22 +40,19 @@
5340
return; // scope 0 at $DIR/cycle.rs:+2:2: +2:2
5441
+ }
5542
+
56-
+ bb2 (cleanup): {
57-
+ drop(_2) -> bb3; // scope 1 at $DIR/cycle.rs:7:1: 7:2
43+
+ bb2: {
44+
+ StorageDead(_5); // scope 1 at $DIR/cycle.rs:6:7: 6:8
45+
+ StorageDead(_4); // scope 1 at $DIR/cycle.rs:6:7: 6:8
46+
+ StorageDead(_3); // scope 1 at $DIR/cycle.rs:6:8: 6:9
47+
+ drop(_2) -> bb1; // scope 1 at $DIR/cycle.rs:7:1: 7:2
5848
+ }
5949
+
6050
+ bb3 (cleanup): {
61-
+ resume; // scope 1 at $DIR/cycle.rs:5:1: 7:2
51+
+ drop(_2) -> bb4; // scope 1 at $DIR/cycle.rs:7:1: 7:2
6252
+ }
6353
+
64-
+ bb4: {
65-
+ StorageDead(_8); // scope 4 at $DIR/cycle.rs:6:7: 6:8
66-
+ StorageDead(_7); // scope 4 at $DIR/cycle.rs:6:8: 6:9
67-
+ StorageDead(_6); // scope 3 at $DIR/cycle.rs:12:5: 12:12
68-
+ StorageDead(_5); // scope 1 at $DIR/cycle.rs:6:7: 6:8
69-
+ StorageDead(_4); // scope 1 at $DIR/cycle.rs:6:7: 6:8
70-
+ StorageDead(_3); // scope 1 at $DIR/cycle.rs:6:8: 6:9
71-
+ drop(_2) -> bb1; // scope 1 at $DIR/cycle.rs:7:1: 7:2
54+
+ bb4 (cleanup): {
55+
+ resume; // scope 1 at $DIR/cycle.rs:5:1: 7:2
7256
}
7357
}
7458

‎src/test/mir-opt/inline/exponential_runtime.main.Inline.diff

+50
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,50 @@
1+
- // MIR for `main` before Inline
2+
+ // MIR for `main` after Inline
3+
4+
fn main() -> () {
5+
let mut _0: (); // return place in scope 0 at $DIR/exponential_runtime.rs:+0:11: +0:11
6+
let _1: (); // in scope 0 at $DIR/exponential_runtime.rs:+1:5: +1:22
7+
+ scope 1 (inlined <() as G>::call) { // at $DIR/exponential_runtime.rs:86:5: 86:22
8+
+ let _2: (); // in scope 1 at $DIR/exponential_runtime.rs:73:9: 73:25
9+
+ let _3: (); // in scope 1 at $DIR/exponential_runtime.rs:74:9: 74:25
10+
+ let _4: (); // in scope 1 at $DIR/exponential_runtime.rs:75:9: 75:25
11+
+ }
12+
13+
bb0: {
14+
StorageLive(_1); // scope 0 at $DIR/exponential_runtime.rs:+1:5: +1:22
15+
- _1 = <() as G>::call() -> bb1; // scope 0 at $DIR/exponential_runtime.rs:+1:5: +1:22
16+
+ StorageLive(_2); // scope 1 at $DIR/exponential_runtime.rs:73:9: 73:25
17+
+ _2 = <() as F>::call() -> bb1; // scope 1 at $DIR/exponential_runtime.rs:73:9: 73:25
18+
// mir::Constant
19+
- // + span: $DIR/exponential_runtime.rs:86:5: 86:20
20+
- // + literal: Const { ty: fn() {<() as G>::call}, val: Value(<ZST>) }
21+
+ // + span: $DIR/exponential_runtime.rs:73:9: 73:23
22+
+ // + literal: Const { ty: fn() {<() as F>::call}, val: Value(<ZST>) }
23+
}
24+
25+
bb1: {
26+
+ StorageDead(_2); // scope 1 at $DIR/exponential_runtime.rs:73:25: 73:26
27+
+ StorageLive(_3); // scope 1 at $DIR/exponential_runtime.rs:74:9: 74:25
28+
+ _3 = <() as F>::call() -> bb2; // scope 1 at $DIR/exponential_runtime.rs:74:9: 74:25
29+
+ // mir::Constant
30+
+ // + span: $DIR/exponential_runtime.rs:74:9: 74:23
31+
+ // + literal: Const { ty: fn() {<() as F>::call}, val: Value(<ZST>) }
32+
+ }
33+
+
34+
+ bb2: {
35+
+ StorageDead(_3); // scope 1 at $DIR/exponential_runtime.rs:74:25: 74:26
36+
+ StorageLive(_4); // scope 1 at $DIR/exponential_runtime.rs:75:9: 75:25
37+
+ _4 = <() as F>::call() -> bb3; // scope 1 at $DIR/exponential_runtime.rs:75:9: 75:25
38+
+ // mir::Constant
39+
+ // + span: $DIR/exponential_runtime.rs:75:9: 75:23
40+
+ // + literal: Const { ty: fn() {<() as F>::call}, val: Value(<ZST>) }
41+
+ }
42+
+
43+
+ bb3: {
44+
+ StorageDead(_4); // scope 1 at $DIR/exponential_runtime.rs:75:25: 75:26
45+
StorageDead(_1); // scope 0 at $DIR/exponential_runtime.rs:+1:22: +1:23
46+
_0 = const (); // scope 0 at $DIR/exponential_runtime.rs:+0:11: +2:2
47+
return; // scope 0 at $DIR/exponential_runtime.rs:+2:2: +2:2
48+
}
49+
}
50+

‎src/test/mir-opt/inline/exponential_runtime.rs

+87
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,87 @@
1+
// Checks that code with exponential runtime does not have exponential behavior in inlining.
2+
3+
trait A {
4+
fn call();
5+
}
6+
7+
trait B {
8+
fn call();
9+
}
10+
impl<T: A> B for T {
11+
#[inline]
12+
fn call() {
13+
<T as A>::call();
14+
<T as A>::call();
15+
<T as A>::call();
16+
}
17+
}
18+
19+
trait C {
20+
fn call();
21+
}
22+
impl<T: B> C for T {
23+
#[inline]
24+
fn call() {
25+
<T as B>::call();
26+
<T as B>::call();
27+
<T as B>::call();
28+
}
29+
}
30+
31+
trait D {
32+
fn call();
33+
}
34+
impl<T: C> D for T {
35+
#[inline]
36+
fn call() {
37+
<T as C>::call();
38+
<T as C>::call();
39+
<T as C>::call();
40+
}
41+
}
42+
43+
trait E {
44+
fn call();
45+
}
46+
impl<T: D> E for T {
47+
#[inline]
48+
fn call() {
49+
<T as D>::call();
50+
<T as D>::call();
51+
<T as D>::call();
52+
}
53+
}
54+
55+
trait F {
56+
fn call();
57+
}
58+
impl<T: E> F for T {
59+
#[inline]
60+
fn call() {
61+
<T as E>::call();
62+
<T as E>::call();
63+
<T as E>::call();
64+
}
65+
}
66+
67+
trait G {
68+
fn call();
69+
}
70+
impl<T: F> G for T {
71+
#[inline]
72+
fn call() {
73+
<T as F>::call();
74+
<T as F>::call();
75+
<T as F>::call();
76+
}
77+
}
78+
79+
impl A for () {
80+
#[inline(never)]
81+
fn call() {}
82+
}
83+
84+
// EMIT_MIR exponential_runtime.main.Inline.diff
85+
fn main() {
86+
<() as G>::call();
87+
}

‎src/test/mir-opt/inline/inline_cycle.one.Inline.diff

+4-7
Original file line numberDiff line numberDiff line change
@@ -5,20 +5,17 @@
55
let mut _0: (); // return place in scope 0 at $DIR/inline_cycle.rs:+0:10: +0:10
66
let _1: (); // in scope 0 at $DIR/inline_cycle.rs:+1:5: +1:24
77
+ scope 1 (inlined <C as Call>::call) { // at $DIR/inline_cycle.rs:14:5: 14:24
8-
+ scope 2 (inlined <A<C> as Call>::call) { // at $DIR/inline_cycle.rs:43:9: 43:23
9-
+ scope 3 (inlined <B<C> as Call>::call) { // at $DIR/inline_cycle.rs:28:9: 28:31
10-
+ }
11-
+ }
128
+ }
139

1410
bb0: {
1511
StorageLive(_1); // scope 0 at $DIR/inline_cycle.rs:+1:5: +1:24
1612
- _1 = <C as Call>::call() -> bb1; // scope 0 at $DIR/inline_cycle.rs:+1:5: +1:24
17-
+ _1 = <C as Call>::call() -> bb1; // scope 3 at $DIR/inline_cycle.rs:36:9: 36:28
13+
+ _1 = <A<C> as Call>::call() -> bb1; // scope 1 at $DIR/inline_cycle.rs:43:9: 43:23
1814
// mir::Constant
1915
- // + span: $DIR/inline_cycle.rs:14:5: 14:22
20-
+ // + span: $DIR/inline_cycle.rs:36:9: 36:26
21-
// + literal: Const { ty: fn() {<C as Call>::call}, val: Value(<ZST>) }
16+
- // + literal: Const { ty: fn() {<C as Call>::call}, val: Value(<ZST>) }
17+
+ // + span: $DIR/inline_cycle.rs:43:9: 43:21
18+
+ // + literal: Const { ty: fn() {<A<C> as Call>::call}, val: Value(<ZST>) }
2219
}
2320

2421
bb1: {

‎src/test/mir-opt/inline/inline_cycle.two.Inline.diff

+7-16
Original file line numberDiff line numberDiff line change
@@ -9,11 +9,6 @@
99
+ debug f => _2; // in scope 1 at $DIR/inline_cycle.rs:53:22: 53:23
1010
+ let _3: (); // in scope 1 at $DIR/inline_cycle.rs:54:5: 54:8
1111
+ let mut _4: (); // in scope 1 at $DIR/inline_cycle.rs:54:5: 54:8
12-
+ scope 2 (inlined <fn() {f} as FnOnce<()>>::call_once - shim(fn() {f})) { // at $DIR/inline_cycle.rs:54:5: 54:8
13-
+ scope 3 (inlined f) { // at $SRC_DIR/core/src/ops/function.rs:LL:COL
14-
+ let _5: (); // in scope 3 at $DIR/inline_cycle.rs:59:5: 59:12
15-
+ }
16-
+ }
1712
+ }
1813

1914
bb0: {
@@ -23,23 +18,19 @@
2318
+ _2 = f; // scope 0 at $DIR/inline_cycle.rs:+1:5: +1:12
2419
// mir::Constant
2520
- // + span: $DIR/inline_cycle.rs:49:5: 49:9
26-
+ // + span: $DIR/inline_cycle.rs:49:10: 49:11
27-
+ // + literal: Const { ty: fn() {f}, val: Value(<ZST>) }
21+
- // + literal: Const { ty: fn(fn() {f}) {call::<fn() {f}>}, val: Value(<ZST>) }
22+
- // mir::Constant
23+
// + span: $DIR/inline_cycle.rs:49:10: 49:11
24+
// + literal: Const { ty: fn() {f}, val: Value(<ZST>) }
2825
+ StorageLive(_3); // scope 1 at $DIR/inline_cycle.rs:54:5: 54:8
2926
+ StorageLive(_4); // scope 1 at $DIR/inline_cycle.rs:54:5: 54:8
30-
+ StorageLive(_5); // scope 3 at $DIR/inline_cycle.rs:59:5: 59:12
31-
+ _5 = call::<fn() {f}>(f) -> bb1; // scope 3 at $DIR/inline_cycle.rs:59:5: 59:12
27+
+ _3 = <fn() {f} as FnOnce<()>>::call_once(move _2, move _4) -> bb1; // scope 1 at $DIR/inline_cycle.rs:54:5: 54:8
3228
+ // mir::Constant
33-
+ // + span: $DIR/inline_cycle.rs:59:5: 59:9
34-
// + literal: Const { ty: fn(fn() {f}) {call::<fn() {f}>}, val: Value(<ZST>) }
35-
// mir::Constant
36-
- // + span: $DIR/inline_cycle.rs:49:10: 49:11
37-
+ // + span: $DIR/inline_cycle.rs:59:10: 59:11
38-
// + literal: Const { ty: fn() {f}, val: Value(<ZST>) }
29+
+ // + span: $DIR/inline_cycle.rs:54:5: 54:6
30+
+ // + literal: Const { ty: extern "rust-call" fn(fn() {f}, ()) -> <fn() {f} as FnOnce<()>>::Output {<fn() {f} as FnOnce<()>>::call_once}, val: Value(<ZST>) }
3931
}
4032

4133
bb1: {
42-
+ StorageDead(_5); // scope 3 at $DIR/inline_cycle.rs:59:12: 59:13
4334
+ StorageDead(_4); // scope 1 at $DIR/inline_cycle.rs:54:7: 54:8
4435
+ StorageDead(_3); // scope 1 at $DIR/inline_cycle.rs:54:8: 54:9
4536
+ StorageDead(_2); // scope 0 at $DIR/inline_cycle.rs:+1:5: +1:12

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