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Specify add_free behaviour on invalid usage #27

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@EwanC EwanC commented Nov 15, 2022

In sycl::free the wording is that that behavior is not defined on invalid usage, so I think we should specify that rather than checking for and throwing an exception.

Issue #10

In [sycl::free](https://registry.khronos.org/SYCL/specs/sycl-2020/html/sycl-2020.html#_memory_deallocation_functions) the wording is that that behavior is not defined on invalid usage,
so I think we should specify that rather than checking for and throwing an exception.

Issue #10
@@ -534,7 +534,7 @@ Table 7. Member functions of the `command_graph` class (memory operations).
using namespace ext::oneapi::experimental;
node add_malloc_device(void *&data, size_t numBytes, const std::vector<node>& dep = {});
----
|Adding a node that encapsulates a memory allocation operation.
|Adds a node that encapsulates a USM device memory allocation operation.
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My understanding is that this is equivalent to a USM device allocation, saying this explicitly means that a reading can just consult that section of the SYCL spec for valid usage of the pointer returned by data. However if add_malloc_device should be used differently, we should specify that expectation here instead.

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I think the usage of the pointers returned should be the same as a regular USM allocation, we could note that specifically here I suppose just to be extra clear.

@@ -562,7 +562,10 @@ Exceptions:
using namespace ext::oneapi::experimental;
node add_free(void *data, const std::vector<node>& dep = {});
----
|Adding a node that encapsulates a memory free operation.
|Adds a node that encapsulates a memory free operation. The memory pointed to
by `data` must be a valid address that has been allocated using one of the USM
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The phrase

must be a valid address that has been allocated using one of the USM allocation routines

means that a user could call add_free using an address that was from a USM allocation function that is not add_malloc_device, but sycl::malloc_[device,host,shared]. I'd like to double check if this is behaviour we want. If not, this language can be changed to "must be a valid address that has been allocated from add_malloc_device"

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I think letting the graph free an allocation it didn't create is very error prone. IMO we should either mandate that it must have been allocated as part of the graph and error if not, or remove allocation/freeing altogether from graphs.

@EwanC EwanC added the Graph Specification Extension Specification related label Nov 15, 2022
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EwanC commented Nov 29, 2022

Closing this without merging, as this should be addressed as part of a larger PR clarifying graph memory semantics - #39

@EwanC EwanC closed this Nov 29, 2022
reble pushed a commit that referenced this pull request May 15, 2023
…callback

The `TypeSystemMap::m_mutex` guards against concurrent modifications
of members of `TypeSystemMap`. In particular, `m_map`.

`TypeSystemMap::ForEach` iterates through the entire `m_map` calling
a user-specified callback for each entry. This is all done while
`m_mutex` is locked. However, there's nothing that guarantees that
the callback itself won't call back into `TypeSystemMap` APIs on the
same thread. This lead to double-locking `m_mutex`, which is undefined
behaviour. We've seen this cause a deadlock in the swift plugin with
following backtrace:

```

int main() {
    std::unique_ptr<int> up = std::make_unique<int>(5);

    volatile int val = *up;
    return val;
}

clang++ -std=c++2a -g -O1 main.cpp

./bin/lldb -o “br se -p return” -o run -o “v *up” -o “expr *up” -b
```

```
frame #4: std::lock_guard<std::mutex>::lock_guard
frame #5: lldb_private::TypeSystemMap::GetTypeSystemForLanguage <<<< Lock #2
frame #6: lldb_private::TypeSystemMap::GetTypeSystemForLanguage
frame #7: lldb_private::Target::GetScratchTypeSystemForLanguage
...
frame #26: lldb_private::SwiftASTContext::LoadLibraryUsingPaths
frame #27: lldb_private::SwiftASTContext::LoadModule
frame #30: swift::ModuleDecl::collectLinkLibraries
frame #31: lldb_private::SwiftASTContext::LoadModule
frame #34: lldb_private::SwiftASTContext::GetCompileUnitImportsImpl
frame #35: lldb_private::SwiftASTContext::PerformCompileUnitImports
frame #36: lldb_private::TypeSystemSwiftTypeRefForExpressions::GetSwiftASTContext
frame #37: lldb_private::TypeSystemSwiftTypeRefForExpressions::GetPersistentExpressionState
frame #38: lldb_private::Target::GetPersistentSymbol
frame #41: lldb_private::TypeSystemMap::ForEach                 <<<< Lock #1
frame #42: lldb_private::Target::GetPersistentSymbol
frame #43: lldb_private::IRExecutionUnit::FindInUserDefinedSymbols
frame #44: lldb_private::IRExecutionUnit::FindSymbol
frame #45: lldb_private::IRExecutionUnit::MemoryManager::GetSymbolAddressAndPresence
frame #46: lldb_private::IRExecutionUnit::MemoryManager::findSymbol
frame #47: non-virtual thunk to lldb_private::IRExecutionUnit::MemoryManager::findSymbol
frame #48: llvm::LinkingSymbolResolver::findSymbol
frame #49: llvm::LegacyJITSymbolResolver::lookup
frame #50: llvm::RuntimeDyldImpl::resolveExternalSymbols
frame #51: llvm::RuntimeDyldImpl::resolveRelocations
frame #52: llvm::MCJIT::finalizeLoadedModules
frame #53: llvm::MCJIT::finalizeObject
frame #54: lldb_private::IRExecutionUnit::ReportAllocations
frame #55: lldb_private::IRExecutionUnit::GetRunnableInfo
frame #56: lldb_private::ClangExpressionParser::PrepareForExecution
frame #57: lldb_private::ClangUserExpression::TryParse
frame #58: lldb_private::ClangUserExpression::Parse
```

Our solution is to simply iterate over a local copy of `m_map`.

**Testing**

* Confirmed on manual reproducer (would reproduce 100% of the time
  before the patch)

Differential Revision: https://reviews.llvm.org/D149949
@EwanC EwanC deleted the free_UB branch June 28, 2023 14:35
EwanC pushed a commit that referenced this pull request Feb 27, 2024
…(#80904)"

This reverts commit b1ac052.

This commit breaks coroutine splitting for non-swift calling convention
functions. In this example:

```ll
; ModuleID = 'repro.ll'
source_filename = "stdlib/test/runtime/test_llcl.mojo"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

@0 = internal constant { i32, i32 } { i32 trunc (i64 sub (i64 ptrtoint (ptr @craSH to i64), i64 ptrtoint (ptr getelementptr inbounds ({ i32, i32 }, ptr @0, i32 0, i32 1) to i64)) to i32), i32 64 }

define dso_local void @af_suspend_fn(ptr %0, i64 %1, ptr %2) #0 {
  ret void
}

define dso_local void @craSH(ptr %0) #0 {
  %2 = call token @llvm.coro.id.async(i32 64, i32 8, i32 0, ptr @0)
  %3 = call ptr @llvm.coro.begin(token %2, ptr null)
  %4 = getelementptr inbounds { ptr, { ptr, ptr }, i64, { ptr, i1 }, i64, i64 }, ptr poison, i32 0, i32 0
  %5 = call ptr @llvm.coro.async.resume()
  store ptr %5, ptr %4, align 8
  %6 = call { ptr, ptr, ptr } (i32, ptr, ptr, ...) @llvm.coro.suspend.async.sl_p0p0p0s(i32 0, ptr %5, ptr @ctxt_proj_fn, ptr @af_suspend_fn, ptr poison, i64 -1, ptr poison)
  ret void
}

define dso_local ptr @ctxt_proj_fn(ptr %0) #0 {
  ret ptr %0
}

; Function Attrs: nomerge nounwind
declare { ptr, ptr, ptr } @llvm.coro.suspend.async.sl_p0p0p0s(i32, ptr, ptr, ...) #1

; Function Attrs: nounwind
declare token @llvm.coro.id.async(i32, i32, i32, ptr) #2

; Function Attrs: nounwind
declare ptr @llvm.coro.begin(token, ptr writeonly) #2

; Function Attrs: nomerge nounwind
declare ptr @llvm.coro.async.resume() #1

attributes #0 = { "target-features"="+adx,+aes,+avx,+avx2,+bmi,+bmi2,+clflushopt,+clwb,+clzero,+crc32,+cx16,+cx8,+f16c,+fma,+fsgsbase,+fxsr,+invpcid,+lzcnt,+mmx,+movbe,+mwaitx,+pclmul,+pku,+popcnt,+prfchw,+rdpid,+rdpru,+rdrnd,+rdseed,+sahf,+sha,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+sse4a,+ssse3,+vaes,+vpclmulqdq,+wbnoinvd,+x87,+xsave,+xsavec,+xsaveopt,+xsaves" }
attributes #1 = { nomerge nounwind }
attributes #2 = { nounwind }
```

This verifier crashes after the `coro-split` pass with

```
cannot guarantee tail call due to mismatched parameter counts
  musttail call void @af_suspend_fn(ptr poison, i64 -1, ptr poison)
LLVM ERROR: Broken function
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: opt ../../../reduced.ll -O0
 #0 0x00007f1d89645c0e __interceptor_backtrace.part.0 /build/gcc-11-XeT9lY/gcc-11-11.4.0/build/x86_64-linux-gnu/libsanitizer/asan/../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:4193:28
 #1 0x0000556d94d254f7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/Unix/Signals.inc:723:22
 #2 0x0000556d94d19a2f llvm::sys::RunSignalHandlers() /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/Signals.cpp:105:20
 #3 0x0000556d94d1aa42 SignalHandler(int) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/Unix/Signals.inc:371:36
 #4 0x00007f1d88e42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #5 0x00007f1d88e969fc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #6 0x00007f1d88e969fc __pthread_kill_internal ./nptl/pthread_kill.c:78:10
 #7 0x00007f1d88e969fc pthread_kill ./nptl/pthread_kill.c:89:10
 #8 0x00007f1d88e42476 gsignal ./signal/../sysdeps/posix/raise.c:27:6
 #9 0x00007f1d88e287f3 abort ./stdlib/abort.c:81:7
 #10 0x0000556d8944be01 std::vector<llvm::json::Value, std::allocator<llvm::json::Value>>::size() const /usr/include/c++/11/bits/stl_vector.h:919:40
 #11 0x0000556d8944be01 bool std::operator==<llvm::json::Value, std::allocator<llvm::json::Value>>(std::vector<llvm::json::Value, std::allocator<llvm::json::Value>> const&, std::vector<llvm::json::Value, std::allocator<llvm::json::Value>> const&) /usr/include/c++/11/bits/stl_vector.h:1893:23
 #12 0x0000556d8944be01 llvm::json::operator==(llvm::json::Array const&, llvm::json::Array const&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/Support/JSON.h:572:69
 #13 0x0000556d8944be01 llvm::json::operator==(llvm::json::Value const&, llvm::json::Value const&) (.cold) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/JSON.cpp:204:28
 #14 0x0000556d949ed2bd llvm::report_fatal_error(char const*, bool) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/ErrorHandling.cpp:82:70
 #15 0x0000556d8e37e876 llvm::SmallVectorBase<unsigned int>::size() const /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallVector.h:91:32
 #16 0x0000556d8e37e876 llvm::SmallVectorTemplateCommon<llvm::DiagnosticInfoOptimizationBase::Argument, void>::end() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallVector.h:282:41
 #17 0x0000556d8e37e876 llvm::SmallVector<llvm::DiagnosticInfoOptimizationBase::Argument, 4u>::~SmallVector() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallVector.h:1215:24
 #18 0x0000556d8e37e876 llvm::DiagnosticInfoOptimizationBase::~DiagnosticInfoOptimizationBase() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/DiagnosticInfo.h:413:7
 #19 0x0000556d8e37e876 llvm::DiagnosticInfoIROptimization::~DiagnosticInfoIROptimization() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/DiagnosticInfo.h:622:7
 #20 0x0000556d8e37e876 llvm::OptimizationRemark::~OptimizationRemark() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/DiagnosticInfo.h:689:7
 #21 0x0000556d8e37e876 operator() /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Transforms/Coroutines/CoroSplit.cpp:2213:14
 #22 0x0000556d8e37e876 emit<llvm::CoroSplitPass::run(llvm::LazyCallGraph::SCC&, llvm::CGSCCAnalysisManager&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&)::<lambda()> > /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/Analysis/OptimizationRemarkEmitter.h:83:12
 #23 0x0000556d8e37e876 llvm::CoroSplitPass::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Transforms/Coroutines/CoroSplit.cpp:2212:13
 #24 0x0000556d8c36ecb1 llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::CoroSplitPass, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 #25 0x0000556d91c1a84f llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Analysis/CGSCCPassManager.cpp:90:12
 #26 0x0000556d8c3690d1 llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 #27 0x0000556d91c2162d llvm::ModuleToPostOrderCGSCCPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Analysis/CGSCCPassManager.cpp:278:18
 #28 0x0000556d8c369035 llvm::detail::PassModel<llvm::Module, llvm::ModuleToPostOrderCGSCCPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 #29 0x0000556d9457abc5 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManager.h:247:20
 #30 0x0000556d8e30979e llvm::CoroConditionalWrapper::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Transforms/Coroutines/CoroConditionalWrapper.cpp:19:74
 #31 0x0000556d8c365755 llvm::detail::PassModel<llvm::Module, llvm::CoroConditionalWrapper, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 #32 0x0000556d9457abc5 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManager.h:247:20
 #33 0x0000556d89818556 llvm::SmallPtrSetImplBase::isSmall() const /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:196:33
 #34 0x0000556d89818556 llvm::SmallPtrSetImplBase::~SmallPtrSetImplBase() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:84:17
 #35 0x0000556d89818556 llvm::SmallPtrSetImpl<llvm::AnalysisKey*>::~SmallPtrSetImpl() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:321:7
 #36 0x0000556d89818556 llvm::SmallPtrSet<llvm::AnalysisKey*, 2u>::~SmallPtrSet() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:427:7
 #37 0x0000556d89818556 llvm::PreservedAnalyses::~PreservedAnalyses() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/Analysis.h:109:7
 #38 0x0000556d89818556 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::ArrayRef<std::function<void (llvm::PassBuilder&)>>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool) /home/ubuntu/modular/third-party/llvm-project/llvm/tools/opt/NewPMDriver.cpp:532:10
 #39 0x0000556d897e3939 optMain /home/ubuntu/modular/third-party/llvm-project/llvm/tools/opt/optdriver.cpp:737:27
 #40 0x0000556d89455461 main /home/ubuntu/modular/third-party/llvm-project/llvm/tools/opt/opt.cpp:25:33
 #41 0x00007f1d88e29d90 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
 #42 0x00007f1d88e29e40 call_init ./csu/../csu/libc-start.c:128:20
 #43 0x00007f1d88e29e40 __libc_start_main ./csu/../csu/libc-start.c:379:5
 #44 0x0000556d897b6335 _start (/home/ubuntu/modular/.derived/third-party/llvm-project/build-relwithdebinfo-asan/bin/opt+0x150c335)
Aborted (core dumped)
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