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Auto merge of rust-lang#46833 - diwic:7c-abort-ffi, r=arielb1
Prevent unwinding past FFI boundaries Second attempt to write a patch to solve this. r? @nikomatsakis ~~So, my biggest issue with this patch is the way the patch determines *what* functions should have an abort landing pad (in `construct_fn`). I would ideally have this code match [src/librustc_trans/callee.rs::get_fn](https://github.com/rust-lang/rust/blob/master/src/librustc_trans/callee.rs#L107-L115) but couldn't find an id that returns true for `is_foreign_item`. Also tried `tcx.has_attr("unwind")` with no luck.~~ FIXED Other issues: * llvm.trap is an SIGILL on amd64. Ideally we could use panic-abort's version of aborting which is nicer but we don't want to depend on that library... * ~~Mir inlining is a stub currently.~~ FIXED (no-op) Also, when reviewing please take into account that I'm new to the code and only partially know what I'm doing... and that I've mostly made made matches on `TerminatorKind::Abort` match either `TerminatorKind::Resume` or `TerminatorKind::Unreachable` based on what looked best.
2 parents 8d4da4f + 4910ed2 commit 51b47dc

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23 files changed

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‎src/Cargo.lock

Lines changed: 1 addition & 0 deletions
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‎src/librustc/ich/impls_mir.rs

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Original file line numberDiff line numberDiff line change
@@ -150,6 +150,7 @@ for mir::TerminatorKind<'gcx> {
150150
targets.hash_stable(hcx, hasher);
151151
}
152152
mir::TerminatorKind::Resume |
153+
mir::TerminatorKind::Abort |
153154
mir::TerminatorKind::Return |
154155
mir::TerminatorKind::GeneratorDrop |
155156
mir::TerminatorKind::Unreachable => {}

‎src/librustc/mir/mod.rs

Lines changed: 11 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -637,6 +637,10 @@ pub enum TerminatorKind<'tcx> {
637637
/// continue. Emitted by build::scope::diverge_cleanup.
638638
Resume,
639639

640+
/// Indicates that the landing pad is finished and that the process
641+
/// should abort. Used to prevent unwinding for foreign items.
642+
Abort,
643+
640644
/// Indicates a normal return. The return place should have
641645
/// been filled in by now. This should occur at most once.
642646
Return,
@@ -759,7 +763,7 @@ impl<'tcx> TerminatorKind<'tcx> {
759763
match *self {
760764
Goto { target: ref b } => slice::from_ref(b).into_cow(),
761765
SwitchInt { targets: ref b, .. } => b[..].into_cow(),
762-
Resume | GeneratorDrop => (&[]).into_cow(),
766+
Resume | Abort | GeneratorDrop => (&[]).into_cow(),
763767
Return => (&[]).into_cow(),
764768
Unreachable => (&[]).into_cow(),
765769
Call { destination: Some((_, t)), cleanup: Some(c), .. } => vec![t, c].into_cow(),
@@ -794,7 +798,7 @@ impl<'tcx> TerminatorKind<'tcx> {
794798
match *self {
795799
Goto { target: ref mut b } => vec![b],
796800
SwitchInt { targets: ref mut b, .. } => b.iter_mut().collect(),
797-
Resume | GeneratorDrop => Vec::new(),
801+
Resume | Abort | GeneratorDrop => Vec::new(),
798802
Return => Vec::new(),
799803
Unreachable => Vec::new(),
800804
Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut c), .. } => vec![t, c],
@@ -823,6 +827,7 @@ impl<'tcx> TerminatorKind<'tcx> {
823827
match *self {
824828
TerminatorKind::Goto { .. } |
825829
TerminatorKind::Resume |
830+
TerminatorKind::Abort |
826831
TerminatorKind::Return |
827832
TerminatorKind::Unreachable |
828833
TerminatorKind::GeneratorDrop |
@@ -918,6 +923,7 @@ impl<'tcx> TerminatorKind<'tcx> {
918923
Return => write!(fmt, "return"),
919924
GeneratorDrop => write!(fmt, "generator_drop"),
920925
Resume => write!(fmt, "resume"),
926+
Abort => write!(fmt, "abort"),
921927
Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
922928
Unreachable => write!(fmt, "unreachable"),
923929
Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
@@ -970,7 +976,7 @@ impl<'tcx> TerminatorKind<'tcx> {
970976
pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
971977
use self::TerminatorKind::*;
972978
match *self {
973-
Return | Resume | Unreachable | GeneratorDrop => vec![],
979+
Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
974980
Goto { .. } => vec!["".into()],
975981
SwitchInt { ref values, .. } => {
976982
values.iter()
@@ -2102,6 +2108,7 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
21022108
},
21032109
GeneratorDrop => GeneratorDrop,
21042110
Resume => Resume,
2111+
Abort => Abort,
21052112
Return => Return,
21062113
Unreachable => Unreachable,
21072114
FalseEdges { real_target, ref imaginary_targets } =>
@@ -2143,6 +2150,7 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
21432150
},
21442151
Goto { .. } |
21452152
Resume |
2153+
Abort |
21462154
Return |
21472155
GeneratorDrop |
21482156
Unreachable |

‎src/librustc/mir/visit.rs

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Original file line numberDiff line numberDiff line change
@@ -432,6 +432,7 @@ macro_rules! make_mir_visitor {
432432
}
433433

434434
TerminatorKind::Resume |
435+
TerminatorKind::Abort |
435436
TerminatorKind::Return |
436437
TerminatorKind::GeneratorDrop |
437438
TerminatorKind::Unreachable => {

‎src/librustc_mir/Cargo.toml

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@@ -14,6 +14,7 @@ graphviz = { path = "../libgraphviz" }
1414
log = "0.3"
1515
log_settings = "0.1.1"
1616
rustc = { path = "../librustc" }
17+
rustc_back = { path = "../librustc_back" }
1718
rustc_const_eval = { path = "../librustc_const_eval" }
1819
rustc_const_math = { path = "../librustc_const_math" }
1920
rustc_data_structures = { path = "../librustc_data_structures" }

‎src/librustc_mir/borrow_check/mod.rs

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@@ -552,6 +552,7 @@ impl<'cx, 'gcx, 'tcx> DataflowResultsConsumer<'cx, 'tcx> for MirBorrowckCtxt<'cx
552552
});
553553
}
554554
TerminatorKind::Goto { target: _ }
555+
| TerminatorKind::Abort
555556
| TerminatorKind::Unreachable
556557
| TerminatorKind::FalseEdges { .. } => {
557558
// no data used, thus irrelevant to borrowck

‎src/librustc_mir/borrow_check/nll/type_check/mod.rs

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Original file line numberDiff line numberDiff line change
@@ -780,6 +780,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
780780
match term.kind {
781781
TerminatorKind::Goto { .. }
782782
| TerminatorKind::Resume
783+
| TerminatorKind::Abort
783784
| TerminatorKind::Return
784785
| TerminatorKind::GeneratorDrop
785786
| TerminatorKind::Unreachable
@@ -1082,6 +1083,9 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
10821083
TerminatorKind::Resume => if !is_cleanup {
10831084
span_mirbug!(self, block_data, "resume on non-cleanup block!")
10841085
},
1086+
TerminatorKind::Abort => if !is_cleanup {
1087+
span_mirbug!(self, block_data, "abort on non-cleanup block!")
1088+
},
10851089
TerminatorKind::Return => if is_cleanup {
10861090
span_mirbug!(self, block_data, "return on cleanup block")
10871091
},

‎src/librustc_mir/build/mod.rs

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@@ -20,6 +20,7 @@ use rustc::mir::visit::{MutVisitor, TyContext};
2020
use rustc::ty::{self, Ty, TyCtxt};
2121
use rustc::ty::subst::Substs;
2222
use rustc::util::nodemap::NodeMap;
23+
use rustc_back::PanicStrategy;
2324
use rustc_const_eval::pattern::{BindingMode, PatternKind};
2425
use rustc_data_structures::indexed_vec::{IndexVec, Idx};
2526
use shim;
@@ -353,6 +354,27 @@ macro_rules! unpack {
353354
};
354355
}
355356

357+
fn should_abort_on_panic<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
358+
fn_id: ast::NodeId,
359+
abi: Abi)
360+
-> bool {
361+
362+
// Not callable from C, so we can safely unwind through these
363+
if abi == Abi::Rust || abi == Abi::RustCall { return false; }
364+
365+
// We never unwind, so it's not relevant to stop an unwind
366+
if tcx.sess.panic_strategy() != PanicStrategy::Unwind { return false; }
367+
368+
// We cannot add landing pads, so don't add one
369+
if tcx.sess.no_landing_pads() { return false; }
370+
371+
// This is a special case: some functions have a C abi but are meant to
372+
// unwind anyway. Don't stop them.
373+
if tcx.has_attr(tcx.hir.local_def_id(fn_id), "unwind") { return false; }
374+
375+
return true;
376+
}
377+
356378
///////////////////////////////////////////////////////////////////////////
357379
/// the main entry point for building MIR for a function
358380
@@ -383,6 +405,10 @@ fn construct_fn<'a, 'gcx, 'tcx, A>(hir: Cx<'a, 'gcx, 'tcx>,
383405
let source_info = builder.source_info(span);
384406
let call_site_s = (call_site_scope, source_info);
385407
unpack!(block = builder.in_scope(call_site_s, LintLevel::Inherited, block, |builder| {
408+
if should_abort_on_panic(tcx, fn_id, abi) {
409+
builder.schedule_abort();
410+
}
411+
386412
let arg_scope_s = (arg_scope, source_info);
387413
unpack!(block = builder.in_scope(arg_scope_s, LintLevel::Inherited, block, |builder| {
388414
builder.args_and_body(block, &arguments, arg_scope, &body.value)

‎src/librustc_mir/build/scope.rs

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Original file line numberDiff line numberDiff line change
@@ -612,6 +612,16 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
612612
}
613613
}
614614

615+
// Schedule an abort block - this is used for some ABIs that cannot unwind
616+
pub fn schedule_abort(&mut self) -> BasicBlock {
617+
self.scopes[0].needs_cleanup = true;
618+
let abortblk = self.cfg.start_new_cleanup_block();
619+
let source_info = self.scopes[0].source_info(self.fn_span);
620+
self.cfg.terminate(abortblk, source_info, TerminatorKind::Abort);
621+
self.cached_resume_block = Some(abortblk);
622+
abortblk
623+
}
624+
615625
// Scheduling drops
616626
// ================
617627
/// Indicates that `place` should be dropped on exit from

‎src/librustc_mir/dataflow/impls/borrows.rs

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@@ -496,6 +496,7 @@ impl<'a, 'gcx, 'tcx> Borrows<'a, 'gcx, 'tcx> {
496496
}
497497
}
498498
}
499+
mir::TerminatorKind::Abort |
499500
mir::TerminatorKind::SwitchInt {..} |
500501
mir::TerminatorKind::Drop {..} |
501502
mir::TerminatorKind::DropAndReplace {..} |

‎src/librustc_mir/dataflow/mod.rs

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Original file line numberDiff line numberDiff line change
@@ -771,6 +771,7 @@ impl<'a, 'tcx: 'a, D> DataflowAnalysis<'a, 'tcx, D> where D: BitDenotation
771771
match bb_data.terminator().kind {
772772
mir::TerminatorKind::Return |
773773
mir::TerminatorKind::Resume |
774+
mir::TerminatorKind::Abort |
774775
mir::TerminatorKind::GeneratorDrop |
775776
mir::TerminatorKind::Unreachable => {}
776777
mir::TerminatorKind::Goto { ref target } |

‎src/librustc_mir/dataflow/move_paths/builder.rs

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@@ -334,6 +334,7 @@ impl<'b, 'a, 'gcx, 'tcx> Gatherer<'b, 'a, 'gcx, 'tcx> {
334334
match term.kind {
335335
TerminatorKind::Goto { target: _ } |
336336
TerminatorKind::Resume |
337+
TerminatorKind::Abort |
337338
TerminatorKind::GeneratorDrop |
338339
TerminatorKind::FalseEdges { .. } |
339340
TerminatorKind::Unreachable => { }

‎src/librustc_mir/interpret/terminator/mod.rs

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@@ -163,6 +163,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
163163
GeneratorDrop => unimplemented!(),
164164
DropAndReplace { .. } => unimplemented!(),
165165
Resume => unimplemented!(),
166+
Abort => unimplemented!(),
166167
FalseEdges { .. } => bug!("should have been eliminated by `simplify_branches` mir pass"),
167168
Unreachable => return err!(Unreachable),
168169
}

‎src/librustc_mir/lib.rs

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@@ -49,6 +49,7 @@ extern crate rustc_errors;
4949
#[macro_use]
5050
extern crate syntax;
5151
extern crate syntax_pos;
52+
extern crate rustc_back;
5253
extern crate rustc_const_math;
5354
extern crate rustc_const_eval;
5455
extern crate core; // for NonZero

‎src/librustc_mir/monomorphize/collector.rs

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@@ -625,6 +625,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
625625
mir::TerminatorKind::Goto { .. } |
626626
mir::TerminatorKind::SwitchInt { .. } |
627627
mir::TerminatorKind::Resume |
628+
mir::TerminatorKind::Abort |
628629
mir::TerminatorKind::Return |
629630
mir::TerminatorKind::Unreachable |
630631
mir::TerminatorKind::Assert { .. } => {}

‎src/librustc_mir/transform/check_unsafety.rs

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Original file line numberDiff line numberDiff line change
@@ -73,6 +73,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
7373
TerminatorKind::DropAndReplace { .. } |
7474
TerminatorKind::GeneratorDrop |
7575
TerminatorKind::Resume |
76+
TerminatorKind::Abort |
7677
TerminatorKind::Return |
7778
TerminatorKind::Unreachable |
7879
TerminatorKind::FalseEdges { .. } => {

‎src/librustc_mir/transform/inline.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -806,6 +806,7 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
806806
*kind = TerminatorKind::Goto { target: tgt }
807807
}
808808
}
809+
TerminatorKind::Abort => { }
809810
TerminatorKind::Unreachable => { }
810811
TerminatorKind::FalseEdges { ref mut real_target, ref mut imaginary_targets } => {
811812
*real_target = self.update_target(*real_target);

‎src/librustc_mir/transform/qualify_consts.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -324,6 +324,7 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
324324
TerminatorKind::SwitchInt {..} |
325325
TerminatorKind::DropAndReplace { .. } |
326326
TerminatorKind::Resume |
327+
TerminatorKind::Abort |
327328
TerminatorKind::GeneratorDrop |
328329
TerminatorKind::Yield { .. } |
329330
TerminatorKind::Unreachable |

‎src/librustc_mir/transform/remove_noop_landing_pads.rs

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Original file line numberDiff line numberDiff line change
@@ -76,6 +76,7 @@ impl RemoveNoopLandingPads {
7676
TerminatorKind::GeneratorDrop |
7777
TerminatorKind::Yield { .. } |
7878
TerminatorKind::Return |
79+
TerminatorKind::Abort |
7980
TerminatorKind::Unreachable |
8081
TerminatorKind::Call { .. } |
8182
TerminatorKind::Assert { .. } |

‎src/librustc_passes/mir_stats.rs

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Original file line numberDiff line numberDiff line change
@@ -113,6 +113,7 @@ impl<'a, 'tcx> mir_visit::Visitor<'tcx> for StatCollector<'a, 'tcx> {
113113
TerminatorKind::Goto { .. } => "TerminatorKind::Goto",
114114
TerminatorKind::SwitchInt { .. } => "TerminatorKind::SwitchInt",
115115
TerminatorKind::Resume => "TerminatorKind::Resume",
116+
TerminatorKind::Abort => "TerminatorKind::Abort",
116117
TerminatorKind::Return => "TerminatorKind::Return",
117118
TerminatorKind::Unreachable => "TerminatorKind::Unreachable",
118119
TerminatorKind::Drop { .. } => "TerminatorKind::Drop",

‎src/librustc_trans/mir/analyze.rs

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Original file line numberDiff line numberDiff line change
@@ -236,6 +236,7 @@ pub fn cleanup_kinds<'a, 'tcx>(mir: &mir::Mir<'tcx>) -> IndexVec<mir::BasicBlock
236236
match data.terminator().kind {
237237
TerminatorKind::Goto { .. } |
238238
TerminatorKind::Resume |
239+
TerminatorKind::Abort |
239240
TerminatorKind::Return |
240241
TerminatorKind::GeneratorDrop |
241242
TerminatorKind::Unreachable |

‎src/librustc_trans/mir/block.rs

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Original file line numberDiff line numberDiff line change
@@ -180,6 +180,13 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
180180
}
181181
}
182182

183+
mir::TerminatorKind::Abort => {
184+
// Call core::intrinsics::abort()
185+
let fnname = bcx.ccx.get_intrinsic(&("llvm.trap"));
186+
bcx.call(fnname, &[], None);
187+
bcx.unreachable();
188+
}
189+
183190
mir::TerminatorKind::Goto { target } => {
184191
funclet_br(self, bcx, target);
185192
}

‎src/test/run-pass/abort-on-c-abi.rs

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,43 @@
1+
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2+
// file at the top-level directory of this distribution and at
3+
// http://rust-lang.org/COPYRIGHT.
4+
//
5+
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6+
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7+
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8+
// option. This file may not be copied, modified, or distributed
9+
// except according to those terms.
10+
11+
// Since we mark some ABIs as "nounwind" to LLVM, we must make sure that
12+
// we never unwind through them.
13+
14+
// ignore-emscripten no processes
15+
16+
use std::{env, panic};
17+
use std::io::prelude::*;
18+
use std::io;
19+
use std::process::{Command, Stdio};
20+
21+
extern "C" fn panic_in_ffi() {
22+
panic!("Test");
23+
}
24+
25+
fn test() {
26+
let _ = panic::catch_unwind(|| { panic_in_ffi(); });
27+
// The process should have aborted by now.
28+
io::stdout().write(b"This should never be printed.\n");
29+
let _ = io::stdout().flush();
30+
}
31+
32+
fn main() {
33+
let args: Vec<String> = env::args().collect();
34+
if args.len() > 1 && args[1] == "test" {
35+
return test();
36+
}
37+
38+
let mut p = Command::new(&args[0])
39+
.stdout(Stdio::piped())
40+
.stdin(Stdio::piped())
41+
.arg("test").spawn().unwrap();
42+
assert!(!p.wait().unwrap().success());
43+
}

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