[SR-6357] [sil-opt] crash while running early inlining: "evaluating cost of access with unknown enforcement?"

[dcci]

Previous ID	SR-6357
Radar	None
Original Reporter	@dcci
Type	Bug

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug
Assignee	None
Priority	Medium

md5: 534ab4497ba13078f650381f7de3c0d9

Issue Description:

Stacktrace:

evaluating cost of access with unknown enforcement?
UNREACHABLE executed at /home/davide/work/swift/swift/lib/SILOptimizer/Utils/SILInliner.cpp:225!
#​0 0x00000000037a788f llvm::sys::PrintStackTrace(llvm::raw_ostream&) /home/davide/work/swift/llvm/lib/Support/Unix/Signals.inc:398:13
#&#8203;1 0x00000000037a7b96 bool __gnu_cxx::operator!=<std::pair<void (*)(void*), void*>*, std::vector<std::pair<void (*)(void*), void*>, std::allocator<std::pair<void (*)(void*), void*>
> > >(__gnu_cxx::__normal_iterator<std::pair<void (*)(void*), void*>*, std::vector<std::pair<void (*)(void*), void*>, std::allocator<std::pair<void (*)(void*), void*> > > > const&,
__gnu_cxx::__normal_iterator<std::pair<void (*)(void*), void*>*, std::vector<std::pair<void (*)(void*), void*>, std::allocator<std::pair<void (*)(void*), void*> > > > const&) /usr/$
ib/gcc/x86_64-redhat-linux/6.3.1/../../../../include/c++/6.3.1/bits/stl_iterator.h:880:27
#&#8203;2 0x00000000037a7b96 llvm::sys::RunSignalHandlers() /home/davide/work/swift/llvm/lib/Support/Signals.cpp:49:0
#&#8203;3 0x00000000037a7b96 SignalHandler(int) /home/davide/work/swift/llvm/lib/Support/Unix/Signals.inc:242:0
#&#8203;4 0x00007f2537c68c30 __restore_rt (/lib64/libpthread.so.0+0x10c30)
#&#8203;5 0x00007f25363c7765 __GI_raise (/lib64/libc.so.6+0x34765)
#&#8203;6 0x00007f25363c936a __GI_abort (/lib64/libc.so.6+0x3636a)
#&#8203;7 0x000000000374c9a9 (./sil-opt+0x374c9a9)
#&#8203;8 0x000000000099788a swift::CanType::CanType(swift::TypeBase*) /home/davide/work/swift/swift/include/swift/AST/Type.h:388:5
#&#8203;9 0x000000000099788a swift::SILType::getSwiftRValueType() const /home/davide/work/swift/swift/include/swift/SIL/SILType.h:163:0
#&#8203;10 0x000000000099788a swift::CanTypeWrapperTraits<swift::MetatypeType>::type swift::SILType::castTo<swift::MetatypeType>() const /home/davide/work/swift/swift/include/swift/SIL/SI$
Type.h:182:0
#&#8203;11 0x000000000099788a swift::instructionInlineCost(swift::SILInstruction&) /home/davide/work/swift/swift/lib/SILOptimizer/Utils/SILInliner.cpp:321:0
#&#8203;12 0x00000000007ed6c8 void ShortestPathAnalysis::analyze<(anonymous namespace)::SILPerformanceInliner::collectAppliesToInline(swift::SILFunction*, llvm::SmallVectorImpl<swift::Ful$
ApplySite>&)::$_4>(swift::ColdBlockInfo&, (anonymous namespace)::SILPerformanceInliner::collectAppliesToInline(swift::SILFunction*, llvm::SmallVectorImpl<swift::FullApplySite>&)::$$
4) /home/davide/work/swift/swift/include/swift/SILOptimizer/Utils/PerformanceInlinerUtils.h:405:28
#&#8203;13 0x00000000007ed6c8 (anonymous namespace)::SILPerformanceInliner::collectAppliesToInline(swift::SILFunction*, llvm::SmallVectorImpl<swift::FullApplySite>&) /home/davide/work/swi$
t/swift/lib/SILOptimizer/Transforms/PerformanceInliner.cpp:696:0
#&#8203;14 0x00000000007eca65 llvm::SmallVectorBase::empty() const /home/davide/work/swift/llvm/include/llvm/ADT/SmallVector.h:60:46
#&#8203;15 0x00000000007eca65 (anonymous namespace)::SILPerformanceInliner::inlineCallsIntoFunction(swift::SILFunction*) /home/davide/work/swift/swift/lib/SILOptimizer/Transforms/Performa$
ceInliner.cpp:812:0
#&#8203;16 0x00000000007eca65 (anonymous namespace)::SILPerformanceInlinerPass::run() /home/davide/work/swift/swift/lib/SILOptimizer/Transforms/PerformanceInliner.cpp:919:0
#&#8203;17 0x00000000006f9fc8 llvm::SmallVectorTemplateCommon<swift::SILAnalysis*, void>::begin() /home/davide/work/swift/llvm/include/llvm/ADT/SmallVector.h:115:45
#&#8203;18 0x00000000006f9fc8 swift::SILPassManager::analysesUnlocked() /home/davide/work/swift/swift/lib/SILOptimizer/PassManager/PassManager.cpp:264:0
#&#8203;19 0x00000000006f9fc8 swift::SILPassManager::runPassOnFunction(swift::SILFunctionTransform*, swift::SILFunction*) /home/davide/work/swift/swift/lib/SILOptimizer/PassManager/PassMa$
ager.cpp:341:0
#&#8203;20 0x00000000006faddb std::vector<swift::SILPassManager::WorklistEntry, std::allocator<swift::SILPassManager::WorklistEntry> >::operator[](unsigned long) /usr/lib/gcc/x86_64-redha$
-linux/6.3.1/../../../../include/c++/6.3.1/bits/stl_vector.h:781:32
#&#8203;21 0x00000000006faddb swift::SILPassManager::runFunctionPasses(llvm::ArrayRef<swift::SILFunctionTransform*>) /home/davide/work/swift/swift/lib/SILOptimizer/PassManager/PassManager$
cpp:426:0
#&#8203;22 0x00000000006fc17c llvm::SmallVectorImpl<swift::SILFunctionTransform*>::clear() /home/davide/work/swift/llvm/include/llvm/ADT/SmallVector.h:349:24
#&#8203;23 0x00000000006fc17c swift::SILPassManager::runOneIteration() /home/davide/work/swift/swift/lib/SILOptimizer/PassManager/PassManager.cpp:525:0

swift version:

commit ec4cd51c14a82063319046eee2b00f814ad3f1c6
Merge: 311a59d 8c0e3fb
Author: Arnold Schwaighofer <aschwaighofer@apple.com>
Date:   Fri Nov 10 10:39:34 2017 -0800

    Merge pull request #&#8203;12857 from aschwaighofer/irgen_objc_callee_guaranteed_closures

    IRGen: emitObjCPartialApplicationForwarder support @callee_guaranteed

Cmdline (the test is in tree):

$ ./sil-opt /home/davide/work/swift/swift/test/SILOptimizer//access_marker_elim.sil -o /dev/null -verify-abort-on-failure=false -allocbox-to-stack -dead-arg-signature-opt -normal-simplify-cfg -arc-sequence-opts -lower-aggregate-instrs -early-codemotion -performance-constant-propagation -arc-sequence-opts -early-inline -normal-simplify-cfg

Going to reduce it, but in the meanwhile, FYI @gottesmm/@eeckstein/@belkadan

[dcci]

Reduced:

public struct S {
}
sil hidden [noinline] @f010_initS : $@convention(thin) () -> @owned S {
  %0 = alloc_box ${ var S }, var, name "s"
  %1 = project_box %0 : ${ var S }, 0
  %7 = begin_access [read] [unknown] %1 : $*S
  %8 = load [trivial] %7 : $*S
  end_access %7 : $*S
  return %8 : $S
}

cmdline:

$ ./sil-opt red.sil -o /dev/null -early-inline
evaluating cost of access with unknown enforcement?
UNREACHABLE executed at /home/davide/work/swift/swift/lib/SILOptimizer/Utils/SILInliner.cpp:225!

I find it funny that the inliner is bothering to run an analysis in a single function translation unit 🙂

[dcci]

I looked at this more closely and it looks like the early inliner expects that enforcement for
begin_access and end_access is actually not unknown.
My take is that, regardless, the optimizer shouldn't crash on this, but either a) degrade gracefully or b) report a fatal error and call it a night.