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@MaskRay MaskRay commented Jul 9, 2023

This can be used to accelerate some XXH64 use cases, primarily:

  • llvm/ADT/StringMap.h StringMapImpl::LookupBucketFor
  • lld (e.g. ELF SHF_MERGE|SHF_STRINGS duplicate elimination, --icf)

llvm#63750

@MaskRay MaskRay force-pushed the xxhash-clean branch 17 times, most recently from 6e6aa09 to 95d1e64 Compare July 10, 2023 02:49
ld.lld SHF_MERGE|SHF_STRINGS duplicate elimination is computation heavy
and utilitizes llvm::xxHash64, a simplified version of XXH64.
Externally many sources confirm that a new variant XXH3 is much faster.

I have picked a few hash implementations and computed the
proportion of time spent on hashing in the overall link time (a debug
build of clang 16):

* status quo: 3.63%
* official XXH64 (`#define XXH_VECTOR XXH_SCALAR`): 3.53%
* official XXH3_64bits (`#define XXH_VECTOR XXH_SCALAR`): 1.21%
* official XXH3_64bits (default, essentially `XXH_SSE2`): 1.22%
* this patch llvm::xxh3_64bits: 1.19%

The remaining part of lld remains unchanged. Consequently, a lower ratio
indicates that hashing is faster. Therefore, it is evident that XXH3 from xxhash
is significantly faster than both the official version and our llvm::xxHash64.

(
string length: count
1-3: 393434
4-8: 2084056
9-16: 2846249
17-128: 5598928
129-240: 1317989
241-: 328058
)

This patch adds heavily simplified https://github.com/Cyan4973/xxHash,
taking account of many simplification ideas from Devin Hussey's xxhash-clean.

Important x86-64 optimization ideas:

* Make XXH3_len_129to240_64b and XXH3_hashLong_64b noinline
* Unroll XXH3_len_17to128_64b
* __restrict does not affect Clang code generation

Beside SHF_MERGE|SHF_STRINGS duplicate elimination, llvm/ADT/StringMap.h
StringMapImpl::LookupBucketFor and a few places in lld can potentially be
accelerated by switching to llvm::xxh3_64bits.
@MaskRay MaskRay closed this Jul 10, 2023
@MaskRay MaskRay deleted the xxhash-clean branch July 10, 2023 03:09
MaskRay pushed a commit that referenced this pull request Jul 15, 2023
…tput

The crash happens in clang::driver::tools::SplitDebugName when Output is
InputInfo::Nothing. It doesn't happen with standalone clang driver because
output is created in Driver::BuildJobsForActionNoCache.

Example backtrace:
```
* thread #1, name = 'clangd', stop reason = hit program assert
  * frame #0: 0x00007ffff5c4eacf libc.so.6`raise + 271
    frame #1: 0x00007ffff5c21ea5 libc.so.6`abort + 295
    frame #2: 0x00007ffff5c21d79 libc.so.6`__assert_fail_base.cold.0 + 15
    frame #3: 0x00007ffff5c47426 libc.so.6`__assert_fail + 70
    frame #4: 0x000055555dc0923c clangd`clang::driver::InputInfo::getFilename(this=0x00007fffffff9398) const at InputInfo.h:84:5
    frame #5: 0x000055555dcd0d8d clangd`clang::driver::tools::SplitDebugName(JA=0x000055555f6c6a50, Args=0x000055555f6d0b80, Input=0x00007fffffff9678, Output=0x00007fffffff9398) at CommonArgs.cpp:1275:40
    frame llvm#6: 0x000055555dc955a5 clangd`clang::driver::tools::Clang::ConstructJob(this=0x000055555f6c69d0, C=0x000055555f6c64a0, JA=0x000055555f6c6a50, Output=0x00007fffffff9398, Inputs=0x00007fffffff9668, Args=0x000055555f6d0b80, LinkingOutput=0x0000000000000000) const at Clang.cpp:5690:33
    frame llvm#7: 0x000055555dbf6b54 clangd`clang::driver::Driver::BuildJobsForActionNoCache(this=0x00007fffffffb5e0, C=0x000055555f6c64a0, A=0x000055555f6c6a50, TC=0x000055555f6c4be0, BoundArch=(Data = 0x0000000000000000, Length = 0), AtTopLevel=true, MultipleArchs=false, LinkingOutput=0x0000000000000000, CachedResults=size=1, TargetDeviceOffloadKind=OFK_None) const at Driver.cpp:5618:10
    frame llvm#8: 0x000055555dbf4ef0 clangd`clang::driver::Driver::BuildJobsForAction(this=0x00007fffffffb5e0, C=0x000055555f6c64a0, A=0x000055555f6c6a50, TC=0x000055555f6c4be0, BoundArch=(Data = 0x0000000000000000, Length = 0), AtTopLevel=true, MultipleArchs=false, LinkingOutput=0x0000000000000000, CachedResults=size=1, TargetDeviceOffloadKind=OFK_None) const at Driver.cpp:5306:26
    frame llvm#9: 0x000055555dbeb590 clangd`clang::driver::Driver::BuildJobs(this=0x00007fffffffb5e0, C=0x000055555f6c64a0) const at Driver.cpp:4844:5
    frame llvm#10: 0x000055555dbe6b0f clangd`clang::driver::Driver::BuildCompilation(this=0x00007fffffffb5e0, ArgList=ArrayRef<const char *> @ 0x00007fffffffb268) at Driver.cpp:1496:3
    frame llvm#11: 0x000055555b0cc0d9 clangd`clang::createInvocation(ArgList=ArrayRef<const char *> @ 0x00007fffffffbb38, Opts=CreateInvocationOptions @ 0x00007fffffffbb90) at CreateInvocationFromCommandLine.cpp:53:52
    frame llvm#12: 0x000055555b378e7b clangd`clang::clangd::buildCompilerInvocation(Inputs=0x00007fffffffca58, D=0x00007fffffffc158, CC1Args=size=0) at Compiler.cpp:116:44
    frame llvm#13: 0x000055555895a6c8 clangd`clang::clangd::(anonymous namespace)::Checker::buildInvocation(this=0x00007fffffffc760, TFS=0x00007fffffffe570, Contents= Has Value=false ) at Check.cpp:212:9
    frame llvm#14: 0x0000555558959cec clangd`clang::clangd::check(File=(Data = "build/test.cpp", Length = 64), TFS=0x00007fffffffe570, Opts=0x00007fffffffe600) at Check.cpp:486:34
    frame llvm#15: 0x000055555892164a clangd`main(argc=4, argv=0x00007fffffffecd8) at ClangdMain.cpp:993:12
    frame llvm#16: 0x00007ffff5c3ad85 libc.so.6`__libc_start_main + 229
    frame llvm#17: 0x00005555585bbe9e clangd`_start + 46
```

Test Plan: ninja ClangDriverTests && tools/clang/unittests/Driver/ClangDriverTests

Differential Revision: https://reviews.llvm.org/D154602
MaskRay pushed a commit that referenced this pull request Jul 24, 2023
ParmVarDecl of BlockDecl is unnecessarily dumped twice.
Remove this duplication as other FunctionDecls.

Fixes llvm#64005 (#2)

Differential Revision: https://reviews.llvm.org/D155985
MaskRay pushed a commit that referenced this pull request Aug 10, 2023
TSan reports the following data race:

  Write of size 4 at 0x000109e0b160 by thread T2 (mutexes: write M0, write M1):
    #0 NativeFile::Close() File.cpp:329
    #1 ConnectionFileDescriptor::Disconnect(lldb_private::Status*) ConnectionFileDescriptorPosix.cpp:232
    #2 Communication::Disconnect(lldb_private::Status*) Communication.cpp:61
    #3 process_gdb_remote::ProcessGDBRemote::DidExit() ProcessGDBRemote.cpp:1164
    #4 Process::SetExitStatus(int, char const*) Process.cpp:1097
    #5 process_gdb_remote::ProcessGDBRemote::MonitorDebugserverProcess(...) ProcessGDBRemote.cpp:3387

  Previous read of size 4 at 0x000109e0b160 by main thread (mutexes: write M2):
    #0 NativeFile::IsValid() const File.h:393
    #1 ConnectionFileDescriptor::IsConnected() const ConnectionFileDescriptorPosix.cpp:121
    #2 Communication::IsConnected() const Communication.cpp:79
    #3 process_gdb_remote::GDBRemoteCommunication::WaitForPacketNoLock(...) GDBRemoteCommunication.cpp:256
    #4 process_gdb_remote::GDBRemoteCommunication::WaitForPacketNoLock(...l) GDBRemoteCommunication.cpp:244
    #5 process_gdb_remote::GDBRemoteClientBase::SendPacketAndWaitForResponseNoLock(llvm::StringRef, StringExtractorGDBRemote&) GDBRemoteClientBase.cpp:246

The problem is that in WaitForPacketNoLock's run loop, it checks that
the connection is still connected. This races with the
ConnectionFileDescriptor disconnecting. Most (but not all) access to the
IOObject in ConnectionFileDescriptorPosix is already gated by the mutex.
This patch just protects IsConnected in the same way.

Differential revision: https://reviews.llvm.org/D157347
MaskRay pushed a commit that referenced this pull request Aug 10, 2023
TSan reports the following race:

  Write of size 8 at 0x000107707ee8 by main thread:
    #0 lldb_private::ThreadedCommunication::StartReadThread(...) ThreadedCommunication.cpp:175
    #1 lldb_private::Process::SetSTDIOFileDescriptor(...) Process.cpp:4533
    #2 lldb_private::Platform::DebugProcess(...) Platform.cpp:1121
    #3 lldb_private::PlatformDarwin::DebugProcess(...) PlatformDarwin.cpp:711
    #4 lldb_private::Target::Launch(...) Target.cpp:3235
    #5 CommandObjectProcessLaunch::DoExecute(...) CommandObjectProcess.cpp:256
    llvm#6 lldb_private::CommandObjectParsed::Execute(...) CommandObject.cpp:751
    llvm#7 lldb_private::CommandInterpreter::HandleCommand(...) CommandInterpreter.cpp:2054

  Previous read of size 8 at 0x000107707ee8 by thread T5:
    #0 lldb_private::HostThread::IsJoinable(...) const HostThread.cpp:30
    #1 lldb_private::ThreadedCommunication::StopReadThread(...) ThreadedCommunication.cpp:192
    #2 lldb_private::Process::ShouldBroadcastEvent(...) Process.cpp:3420
    #3 lldb_private::Process::HandlePrivateEvent(...) Process.cpp:3728
    #4 lldb_private::Process::RunPrivateStateThread(...) Process.cpp:3914
    #5 std::__1::__function::__func<lldb_private::Process::StartPrivateStateThread(...) function.h:356
    llvm#6 lldb_private::HostNativeThreadBase::ThreadCreateTrampoline(...) HostNativeThreadBase.cpp:62
    llvm#7 lldb_private::HostThreadMacOSX::ThreadCreateTrampoline(...) HostThreadMacOSX.mm:18

The problem is the lack of synchronization between starting and stopping
the read thread. This patch fixes that by protecting those operations
with a mutex.

Differential revision: https://reviews.llvm.org/D157361
MaskRay pushed a commit that referenced this pull request Aug 10, 2023
TSan reports the following data race:

  Write of size 4 at 0x000109e0b160 by thread T2 (...):
    #0 lldb_private::NativeFile::Close() File.cpp:329
    #1 lldb_private::ConnectionFileDescriptor::Disconnect(...) ConnectionFileDescriptorPosix.cpp:232
    #2 lldb_private::Communication::Disconnect(...) Communication.cpp:61
    #3 lldb_private::process_gdb_remote::ProcessGDBRemote::DidExit() ProcessGDBRemote.cpp:1164
    #4 lldb_private::Process::SetExitStatus(...) Process.cpp:1097
    #5 lldb_private::process_gdb_remote::ProcessGDBRemote::MonitorDebugserverProcess(...) ProcessGDBRemote.cpp:3387

  Previous read of size 4 at 0x000109e0b160 by main thread (...):
    #0 lldb_private::NativeFile::IsValid() const File.h:393
    #1 lldb_private::ConnectionFileDescriptor::IsConnected() const ConnectionFileDescriptorPosix.cpp:121
    #2 lldb_private::Communication::IsConnected() const Communication.cpp:79
    #3 lldb_private::process_gdb_remote::GDBRemoteCommunication::WaitForPacketNoLock(...) GDBRemoteCommunication.cpp:256
    #4 lldb_private::process_gdb_remote::GDBRemoteCommunication::WaitForPacketNoLock(...) GDBRemoteCommunication.cpp:244
    #5 lldb_private::process_gdb_remote::GDBRemoteClientBase::SendPacketAndWaitForResponseNoLock(...) GDBRemoteClientBase.cpp:246

I originally tried fixing the problem at the ConnectionFileDescriptor
level, but that operates on an IOObject which can have different thread
safety guarantees depending on its implementation.

For this particular issue, the problem is specific to NativeFile.
NativeFile can hold a file descriptor and/or a file stream. Throughout
its implementation, it checks if the descriptor or stream is valid and
do some operation on it if it is. While that works in a single threaded
environment, nothing prevents another thread from modifying the
descriptor or stream between the IsValid check and when it's actually
being used.

This patch prevents such issues by returning a ValueGuard RAII object.
As long as the object is in scope, the value is guaranteed by a lock.

Differential revision: https://reviews.llvm.org/D157347
MaskRay pushed a commit that referenced this pull request Aug 17, 2023
Thread sanitizer reports the following data race:

```
WARNING: ThreadSanitizer: data race (pid=43201)
  Write of size 4 at 0x00010520c474 by thread T1 (mutexes: write M0, write M1):
    #0 lldb_private::PipePosix::CloseWriteFileDescriptor() PipePosix.cpp:242 (liblldb.18.0.0git.dylib:arm64+0x414700) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #1 lldb_private::PipePosix::Close() PipePosix.cpp:217 (liblldb.18.0.0git.dylib:arm64+0x4144e8) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #2 lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Status*) ConnectionFileDescriptorPosix.cpp:239 (liblldb.18.0.0git.dylib:arm64+0x40a620) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #3 lldb_private::Communication::Disconnect(lldb_private::Status*) Communication.cpp:61 (liblldb.18.0.0git.dylib:arm64+0x2a9318) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #4 lldb_private::process_gdb_remote::ProcessGDBRemote::DidExit() ProcessGDBRemote.cpp:1167 (liblldb.18.0.0git.dylib:arm64+0x8ed984) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)

  Previous read of size 4 at 0x00010520c474 by main thread (mutexes: write M2, write M3):
    #0 lldb_private::PipePosix::CanWrite() const PipePosix.cpp:229 (liblldb.18.0.0git.dylib:arm64+0x4145e4) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #1 lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Status*) ConnectionFileDescriptorPosix.cpp:212 (liblldb.18.0.0git.dylib:arm64+0x40a4a8) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #2 lldb_private::Communication::Disconnect(lldb_private::Status*) Communication.cpp:61 (liblldb.18.0.0git.dylib:arm64+0x2a9318) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #3 lldb_private::process_gdb_remote::GDBRemoteCommunication::WaitForPacketNoLock(StringExtractorGDBRemote&, lldb_private::Timeout<std::__1::ratio<1l, 1000000l>>, bool) GDBRemoteCommunication.cpp:373 (liblldb.18.0.0git.dylib:arm64+0x8b9c48) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
    #4 lldb_private::process_gdb_remote::GDBRemoteCommunication::WaitForPacketNoLock(StringExtractorGDBRemote&, lldb_private::Timeout<std::__1::ratio<1l, 1000000l>>, bool) GDBRemoteCommunication.cpp:243 (liblldb.18.0.0git.dylib:arm64+0x8b9904) (BuildId: 2983976beb2637b5943bff32fd12eb8932000000200000000100000000000e00)
```

Fix this by adding a mutex to PipePosix.

Differential Revision: https://reviews.llvm.org/D157654
MaskRay pushed a commit that referenced this pull request Aug 19, 2023
ThreadSanitizer reports the following issue:

```
  Write of size 8 at 0x00010a70abb0 by thread T3 (mutexes: write M0):
    #0 lldb_private::ThreadList::Update(lldb_private::ThreadList&) ThreadList.cpp:741 (liblldb.18.0.0git.dylib:arm64+0x5dedf4) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
    #1 lldb_private::Process::UpdateThreadListIfNeeded() Process.cpp:1212 (liblldb.18.0.0git.dylib:arm64+0x53bbec) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)

  Previous read of size 8 at 0x00010a70abb0 by main thread (mutexes: write M1):
    #0 lldb_private::ThreadList::GetMutex() const ThreadList.cpp:785 (liblldb.18.0.0git.dylib:arm64+0x5df138) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
    #1 lldb_private::ThreadList::DidResume() ThreadList.cpp:656 (liblldb.18.0.0git.dylib:arm64+0x5de5c0) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
    #2 lldb_private::Process::PrivateResume() Process.cpp:3130 (liblldb.18.0.0git.dylib:arm64+0x53cd7c) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
```

Fix this by only using the mutex in ThreadList and removing the one in
process entirely.

Differential Revision: https://reviews.llvm.org/D158034
MaskRay pushed a commit that referenced this pull request Aug 22, 2023
Replace `BPFMIPeepholeTruncElim` by adding an overload for
`TargetLowering::isZExtFree()` aware that zero extension is
free for `ISD::LOAD`.

Short description
=================

The `BPFMIPeepholeTruncElim` handles two patterns:

Pattern #1:

    %1 = LDB %0, ...              %1 = LDB %0, ...
    %2 = AND_ri %1, 0xff      ->  %2 = MOV_ri %1    <-- (!)

Pattern #2:

    bb.1:                         bb.1:
      %a = LDB %0, ...              %a = LDB %0, ...
      br %bb3                       br %bb3
    bb.2:                         bb.2:
      %b = LDB %0, ...        ->    %b = LDB %0, ...
      br %bb3                       br %bb3
    bb.3:                         bb.3:
      %1 = PHI %a, %b               %1 = PHI %a, %b
      %2 = AND_ri %1, 0xff          %2 = MOV_ri %1  <-- (!)

Plus variations:
- AND_ri_32 instead of AND_ri
- SLL/SLR instead of AND_ri
- LDH, LDW, LDB32, LDH32, LDW32

Both patterns could be handled by built-in transformations at
instruction selection phase if suitable `isZExtFree()` implementation
is provided. The idea is borrowed from `ARMTargetLowering::isZExtFree`.

When evaluating on BPF kernel selftests and remove_truncate_*.ll LLVM
test cases this revisions performs slightly better than
BPFMIPeepholeTruncElim, see "Impact" section below for details.

Commit also adds a few test cases to make sure that patterns in
question are handled.

Long description
================

Why this works: Pattern #1
--------------------------

Consider the following example:

    define i1 @foo(ptr %p) {
    entry:
      %a = load i8, ptr %p, align 1
      %cond = icmp eq i8 %a, 0
      ret i1 %cond
    }

Log for `llc -mcpu=v2 -mtriple=bpfel -debug-only=isel` command:

    ...
    Type-legalized selection DAG: %bb.0 'foo:entry'
    SelectionDAG has 13 nodes:
      t0: ch,glue = EntryToken
              t2: i64,ch = CopyFromReg t0, Register:i64 %0
            t16: i64,ch = load<(load (s8) from %ir.p), anyext from i8> t0, t2, undef:i64
          t19: i64 = and t16, Constant:i64<255>
        t17: i64 = setcc t19, Constant:i64<0>, seteq:ch
      t11: ch,glue = CopyToReg t0, Register:i64 $r0, t17
      t12: ch = BPFISD::RET_GLUE t11, Register:i64 $r0, t11:1
    ...
    Replacing.1 t19: i64 = and t16, Constant:i64<255>
    With: t16: i64,ch = load<(load (s8) from %ir.p), anyext from i8> t0, t2, undef:i64
     and 0 other values
    ...
    Optimized type-legalized selection DAG: %bb.0 'foo:entry'
    SelectionDAG has 11 nodes:
      t0: ch,glue = EntryToken
            t2: i64,ch = CopyFromReg t0, Register:i64 %0
          t20: i64,ch = load<(load (s8) from %ir.p), zext from i8> t0, t2, undef:i64
        t17: i64 = setcc t20, Constant:i64<0>, seteq:ch
      t11: ch,glue = CopyToReg t0, Register:i64 $r0, t17
      t12: ch = BPFISD::RET_GLUE t11, Register:i64 $r0, t11:1
    ...

Note:
- Optimized type-legalized selection DAG:
  - `t19 = and t16, 255` had been replaced by `t16` (load).
  - Patterns like `(and (load ... i8), 255)` are replaced by `load`
    in `DAGCombiner::BackwardsPropagateMask` called from
    `DAGCombiner::visitAND`.
  - Similarly patterns like `(shl (srl ..., 56), 56)` are replaced by
    `(and ..., 255)` in `DAGCombiner::visitSRL` (this function is huge,
    look for `TLI.shouldFoldConstantShiftPairToMask()` call).

Why this works: Pattern #2
--------------------------

Consider the following example:

    define i1 @foo(ptr %p) {
    entry:
      %a = load i8, ptr %p, align 1
      br label %next

    next:
      %cond = icmp eq i8 %a, 0
      ret i1 %cond
    }

Consider log for `llc -mcpu=v2 -mtriple=bpfel -debug-only=isel` command.
Log for first basic block:

    Initial selection DAG: %bb.0 'foo:entry'
    SelectionDAG has 9 nodes:
      t0: ch,glue = EntryToken
      t3: i64 = Constant<0>
            t2: i64,ch = CopyFromReg t0, Register:i64 %1
          t5: i8,ch = load<(load (s8) from %ir.p)> t0, t2, undef:i64
        t6: i64 = zero_extend t5
      t8: ch = CopyToReg t0, Register:i64 %0, t6
    ...
    Replacing.1 t6: i64 = zero_extend t5
    With: t9: i64,ch = load<(load (s8) from %ir.p), zext from i8> t0, t2, undef:i64
     and 0 other values
    ...
    Optimized lowered selection DAG: %bb.0 'foo:entry'
    SelectionDAG has 7 nodes:
      t0: ch,glue = EntryToken
          t2: i64,ch = CopyFromReg t0, Register:i64 %1
        t9: i64,ch = load<(load (s8) from %ir.p), zext from i8> t0, t2, undef:i64
      t8: ch = CopyToReg t0, Register:i64 %0, t9

Note:
- Initial selection DAG:
  - `%a = load ...` is lowered as `t6 = (zero_extend (load ...))`
    w/o special `isZExtFree()` overload added by this commit
    it is instead lowered as `t6 = (any_extend (load ...))`.
  - The decision to generate `zero_extend` or `any_extend` is
    done in `RegsForValue::getCopyToRegs` called from
    `SelectionDAGBuilder::CopyValueToVirtualRegister`:
    - if `isZExtFree()` for load returns true `zero_extend` is used;
    - `any_extend` is used otherwise.
- Optimized lowered selection DAG:
  - `t6 = (any_extend (load ...))` is replaced by
    `t9 = load ..., zext from i8`
    This is done by `DagCombiner.cpp:tryToFoldExtOfLoad()` called from
    `DAGCombiner::visitZERO_EXTEND`.

Log for second basic block:

    Initial selection DAG: %bb.1 'foo:next'
    SelectionDAG has 13 nodes:
      t0: ch,glue = EntryToken
                t2: i64,ch = CopyFromReg t0, Register:i64 %0
              t4: i64 = AssertZext t2, ValueType:ch:i8
            t5: i8 = truncate t4
          t8: i1 = setcc t5, Constant:i8<0>, seteq:ch
        t9: i64 = any_extend t8
      t11: ch,glue = CopyToReg t0, Register:i64 $r0, t9
      t12: ch = BPFISD::RET_GLUE t11, Register:i64 $r0, t11:1
    ...
    Replacing.2 t18: i64 = and t4, Constant:i64<255>
    With: t4: i64 = AssertZext t2, ValueType:ch:i8
    ...
    Type-legalized selection DAG: %bb.1 'foo:next'
    SelectionDAG has 13 nodes:
      t0: ch,glue = EntryToken
              t2: i64,ch = CopyFromReg t0, Register:i64 %0
            t4: i64 = AssertZext t2, ValueType:ch:i8
          t18: i64 = and t4, Constant:i64<255>
        t16: i64 = setcc t18, Constant:i64<0>, seteq:ch
      t11: ch,glue = CopyToReg t0, Register:i64 $r0, t16
      t12: ch = BPFISD::RET_GLUE t11, Register:i64 $r0, t11:1
    ...
    Optimized type-legalized selection DAG: %bb.1 'foo:next'
    SelectionDAG has 11 nodes:
      t0: ch,glue = EntryToken
            t2: i64,ch = CopyFromReg t0, Register:i64 %0
          t4: i64 = AssertZext t2, ValueType:ch:i8
        t16: i64 = setcc t4, Constant:i64<0>, seteq:ch
      t11: ch,glue = CopyToReg t0, Register:i64 $r0, t16
      t12: ch = BPFISD::RET_GLUE t11, Register:i64 $r0, t11:1
    ...

Note:
- Initial selection DAG:
  - `t0` is an input value for this basic block, it corresponds load
    instruction (`t9`) from the first basic block.
  - It is accessed within basic block via
    `t4` (AssertZext (CopyFromReg t0, ...)).
  - The `AssertZext` is generated by RegsForValue::getCopyFromRegs
    called from SelectionDAGBuilder::getCopyFromRegs, it is generated
    only when `LiveOutInfo` with known number of leading zeros is
    present for `t0`.
  - Known register bits in `LiveOutInfo` are computed by
    `SelectionDAG::computeKnownBits` called from
    `SelectionDAGISel::ComputeLiveOutVRegInfo`.
  - `computeKnownBits()` generates leading zeros information for
    `(load ..., zext from ...)` but *does not* generate leading zeros
    information for `(load ..., anyext from ...)`.
    This is why `isZExtFree()` added in this commit is important.
- Type-legalized selection DAG:
  - `t5 = truncate t4` is replaced by `t18 = and t4, 255`
- Optimized type-legalized selection DAG:
  - `t18 = and t4, 255` is replaced by `t4`, this is done by
    `DAGCombiner::SimplifyDemandedBits` called from
    `DAGCombiner::visitAND`, which simplifies patterns like
    `(and (assertzext ...))`

Impact
------

This change covers all remove_truncate_*.ll test cases:
- for -mcpu=v4 there are no changes in the generated code;
- for -mcpu=v2 code generated for remove_truncate_7 and
  remove_truncate_8 improved slightly, for other tests it is
  unchanged.

For remove_truncate_7:

    Before this revision                 After this revision
    --------------------                 -------------------
        r1 <<= 0x20                          r1 <<= 0x20
        r1 >>= 0x20                          r1 >>= 0x20
        if r1 == 0x0 goto +0x2 <LBB0_2>      if r1 == 0x0 goto +0x2 <LBB0_2>
        r1 = *(u32 *)(r2 + 0x0)              r0 = *(u32 *)(r2 + 0x0)
        goto +0x1 <LBB0_3>                   goto +0x1 <LBB0_3>
    <LBB0_2>:                            <LBB0_2>:
        r1 = *(u32 *)(r2 + 0x4)              r0 = *(u32 *)(r2 + 0x4)
    <LBB0_3>:                            <LBB0_3>:
        r0 = r1                              exit
        exit

For remove_truncate_8:

    Before this revision                 After this revision
    --------------------                 -------------------
        r2 = *(u32 *)(r1 + 0x0)              r2 = *(u32 *)(r1 + 0x0)
        r3 = r2                              r3 = r2
        r3 <<= 0x20                          r3 <<= 0x20
        r4 = r3                              r3 s>>= 0x20
        r4 s>>= 0x20
        if r4 s> 0x2 goto +0x5 <LBB0_3>      if r3 s> 0x2 goto +0x4 <LBB0_3>
        r4 = *(u32 *)(r1 + 0x4)              r3 = *(u32 *)(r1 + 0x4)
        r3 >>= 0x20
        if r3 >= r4 goto +0x2 <LBB0_3>       if r2 >= r3 goto +0x2 <LBB0_3>
        r2 += 0x2                            r2 += 0x2
        *(u32 *)(r1 + 0x0) = r2              *(u32 *)(r1 + 0x0) = r2
    <LBB0_3>:                            <LBB0_3>:
        r0 = 0x3                             r0 = 0x3
        exit                                 exit

For kernel BPF selftests statistics is as follows: (-mcpu=v4):
- For -mcpu=v4: 9 out of 655 object files have differences,
  in all cases total number of instructions marginally decreased
  (-27 instructions).
- For -mcpu=v2: 9 out of 655 object files have differences:
  - For 19 object files number of instruction decreased
    (-129 instruction in total): some redundant `rX &= 0xffff`
    and register to register assignments removed;
  - For 2 object files number of instructions increased +2
    instructions in each file.

Both -mcpu=v2 instruction increases could be reduced to the same
example:

    define void @foo(ptr %p) {
    entry:
      %a = load i32, ptr %p, align 4
      %b = sext i32 %a to i64
      %c = icmp ult i64 1, %b
      br i1 %c, label %next, label %end

    next:
      call void inttoptr (i64 62 to ptr)(i32 %a)
      br label %end

    end:
      ret void
    }

Note that this example uses value loaded to `%a` both as a sign
extended (`%b`) and as zero extended (`%a` passed as parameter).
Here is the difference in final assembly code:

    Before this revision          After this revision
    --------------------          -------------------
        r1 = *(u32 *)(r1 + 0)         r1 = *(u32 *)(r1 + 0)
        r1 <<= 32                     r1 <<= 32
        r1 s>>= 32                    r1 s>>= 32
        if r1 < 2 goto <LBB0_2>       if r1 < 2 goto <LBB0_2>
                                      r1 <<= 32
                                      r1 >>= 32
        call 62                       call 62
    <LBB0_2>:                     <LBB0_2>:
        exit                          exit

Before this commit `%a` is passed to call as a sign extended value,
after this commit `%a` is passed to call as a zero extended value,
both are correct as 32-bit sub-register is the same.

The difference comes from `DAGCombiner` operation on the initial DAG:

Initial selection DAG before this commit:

    t5: i32,ch = load<(load (s32) from %ir.p)> t0, t2, undef:i64
          t6: i64 = any_extend t5         <--------------------- (1)
        t8: ch = CopyToReg t0, Register:i64 %0, t6
            t9: i64 = sign_extend t5
          t12: i1 = setcc Constant:i64<1>, t9, setult:ch

Initial selection DAG after this commit:

    t5: i32,ch = load<(load (s32) from %ir.p)> t0, t2, undef:i64
          t6: i64 = zero_extend t5        <--------------------- (2)
        t8: ch = CopyToReg t0, Register:i64 %0, t6
            t9: i64 = sign_extend t5
          t12: i1 = setcc Constant:i64<1>, t9, setult:ch

The node `t9` is processed before node `t6` and `load` instruction is
combined to load with sign extension:

    Replacing.1 t9: i64 = sign_extend t5
    With: t30: i64,ch = load<(load (s32) from %ir.p), sext from i32> t0, t2, undef:i64
     and 0 other values
    Replacing.1 t5: i32,ch = load<(load (s32) from %ir.p)> t0, t2, undef:i64
    With: t31: i32 = truncate t30
     and 1 other values

This is done by `DAGCombiner.cpp:tryToFoldExtOfLoad` called from
`DAGCombiner::visitSIGN_EXTEND`. Note that `t5` is used by `t6` which
is `any_extend` in (1) and `zero_extend` in (2).
`tryToFoldExtOfLoad()` rewrites such uses of `t5` differently:
- `any_extend` is simply removed
- `zero_extend` is replaced by `and t30, 0xffffffff`, which is later
  converted to a pair of shifts. This pair of shifts survives till the
  end of translation.

Differential Revision: https://reviews.llvm.org/D157870
MaskRay pushed a commit that referenced this pull request Aug 29, 2023
This reverts commit 0e63f1a.

clang-format started to crash with contents like:
a.h:
```
```
$ clang-format a.h
```
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: ../llvm/build/bin/clang-format a.h
 #0 0x0000560b689fe177 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/local/google/home/kadircet/repos/llvm/llvm/lib/Support/Unix/Signals.inc:723:13
 #1 0x0000560b689fbfbe llvm::sys::RunSignalHandlers() /usr/local/google/home/kadircet/repos/llvm/llvm/lib/Support/Signals.cpp:106:18
 #2 0x0000560b689feaca SignalHandler(int) /usr/local/google/home/kadircet/repos/llvm/llvm/lib/Support/Unix/Signals.inc:413:1
 #3 0x00007f030405a540 (/lib/x86_64-linux-gnu/libc.so.6+0x3c540)
 #4 0x0000560b68a9a980 is /usr/local/google/home/kadircet/repos/llvm/clang/include/clang/Lex/Token.h:98:44
 #5 0x0000560b68a9a980 is /usr/local/google/home/kadircet/repos/llvm/clang/lib/Format/FormatToken.h:562:51
 llvm#6 0x0000560b68a9a980 startsSequenceInternal<clang::tok::TokenKind, clang::tok::TokenKind> /usr/local/google/home/kadircet/repos/llvm/clang/lib/Format/FormatToken.h:831:9
 llvm#7 0x0000560b68a9a980 startsSequence<clang::tok::TokenKind, clang::tok::TokenKind> /usr/local/google/home/kadircet/repos/llvm/clang/lib/Format/FormatToken.h:600:12
 llvm#8 0x0000560b68a9a980 getFunctionName /usr/local/google/home/kadircet/repos/llvm/clang/lib/Format/TokenAnnotator.cpp:3131:17
 llvm#9 0x0000560b68a9a980 clang::format::TokenAnnotator::annotate(clang::format::AnnotatedLine&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Format/TokenAnnotator.cpp:3191:17
Segmentation fault
```
MaskRay pushed a commit that referenced this pull request Dec 8, 2024
## Description

This PR fixes a segmentation fault that occurs when passing options
requiring arguments via `-Xopenmp-target=<triple>`. The issue was that
the function `Driver::getOffloadArchs` did not properly parse the
extracted option, but instead assumed it was valid, leading to a crash
when incomplete arguments were provided.

## Backtrace

```sh
llvm-project/build/bin/clang++ main.cpp -fopenmp=libomp -fopenmp-targets=powerpc64le-ibm-linux-gnu -Xopenmp-target=powerpc64le-ibm-linux-gnu -o 
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: llvm-project/build/bin/clang++ main.cpp -fopenmp=libomp -fopenmp-targets=powerpc64le-ibm-linux-gnu -Xopenmp-target=powerpc64le-ibm-linux-gnu -o
1.      Compilation construction
2.      Building compilation actions
 #0 0x0000562fb21c363b llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (llvm-project/build/bin/clang+++0x392f63b)
 #1 0x0000562fb21c0e3c SignalHandler(int) Signals.cpp:0:0
 #2 0x00007fcbf6c81420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #3 0x0000562fb1fa5d70 llvm::opt::Option::matches(llvm::opt::OptSpecifier) const (llvm-project/build/bin/clang+++0x3711d70)
 #4 0x0000562fb2a78e7d clang::driver::Driver::getOffloadArchs(clang::driver::Compilation&, llvm::opt::DerivedArgList const&, clang::driver::Action::OffloadKind, clang::driver::ToolChain const*, bool) const (llvm-project/build/bin/clang+++0x41e4e7d)
 #5 0x0000562fb2a7a9aa clang::driver::Driver::BuildOffloadingActions(clang::driver::Compilation&, llvm::opt::DerivedArgList&, std::pair<clang::driver::types::ID, llvm::opt::Arg const*> const&, clang::driver::Action*) const (.part.1164) Driver.cpp:0:0
 llvm#6 0x0000562fb2a7c093 clang::driver::Driver::BuildActions(clang::driver::Compilation&, llvm::opt::DerivedArgList&, llvm::SmallVector<std::pair<clang::driver::types::ID, llvm::opt::Arg const*>, 16u> const&, llvm::SmallVector<clang::driver::Action*, 3u>&) const (llvm-project/build/bin/clang+++0x41e8093)
 llvm#7 0x0000562fb2a8395d clang::driver::Driver::BuildCompilation(llvm::ArrayRef<char const*>) (llvm-project/build/bin/clang+++0x41ef95d)
 llvm#8 0x0000562faf92684c clang_main(int, char**, llvm::ToolContext const&) (llvm-project/build/bin/clang+++0x109284c)
 llvm#9 0x0000562faf826cc6 main (llvm-project/build/bin/clang+++0xf92cc6)
llvm#10 0x00007fcbf6699083 __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:342:3
llvm#11 0x0000562faf923a5e _start (llvm-project/build/bin/clang+++0x108fa5e)
[1]    2628042 segmentation fault (core dumped)   main.cpp -fopenmp=libomp -fopenmp-targets=powerpc64le-ibm-linux-gnu  -o
```
MaskRay pushed a commit that referenced this pull request Dec 8, 2024
llvm#118923)

…d reentry.

These utilities provide new, more generic and easier to use support for
lazy compilation in ORC.

LazyReexportsManager is an alternative to LazyCallThroughManager. It
takes requests for lazy re-entry points in the form of an alias map:
lazy-reexports = {
  ( <entry point symbol #1>, <implementation symbol #1> ),
  ( <entry point symbol #2>, <implementation symbol #2> ),
  ...
  ( <entry point symbol #n>, <implementation symbol #n> )
}

LazyReexportsManager then:
1. binds the entry points to the implementation names in an internal
table.
2. creates a JIT re-entry trampoline for each entry point.
3. creates a redirectable symbol for each of the entry point name and
binds redirectable symbol to the corresponding reentry trampoline.

When an entry point symbol is first called at runtime (which may be on
any thread of the JIT'd program) it will re-enter the JIT via the
trampoline and trigger a lookup for the implementation symbol stored in
LazyReexportsManager's internal table. When the lookup completes the
entry point symbol will be updated (via the RedirectableSymbolManager)
to point at the implementation symbol, and execution will proceed to the
implementation symbol.

Actual construction of the re-entry trampolines and redirectable symbols
is delegated to an EmitTrampolines functor and the
RedirectableSymbolsManager respectively.

JITLinkReentryTrampolines.h provides a JITLink-based implementation of
the EmitTrampolines functor. (AArch64 only in this patch, but other
architectures will be added in the near future).

Register state save and reentry functionality is added to the ORC
runtime in the __orc_rt_sysv_resolve and __orc_rt_resolve_implementation
functions (the latter is generic, the former will need custom
implementations for each ABI and architecture to be supported, however
this should be much less effort than the existing OrcABISupport
approach, since the ORC runtime allows this code to be written as native
assembly).

The resulting system:
1. Works equally well for in-process and out-of-process JIT'd code.
2. Requires less boilerplate to set up.

Given an ObjectLinkingLayer and PlatformJD (JITDylib containing the ORC
runtime), setup is just:

```c++
auto RSMgr = JITLinkRedirectableSymbolManager::Create(OLL);
if (!RSMgr)
  return RSMgr.takeError();

auto LRMgr = createJITLinkLazyReexportsManager(OLL, **RSMgr, PlatformJD);
if (!LRMgr)
  return LRMgr.takeError();
```

after which lazy reexports can be introduced with:

```c++
JD.define(lazyReexports(LRMgr, <alias map>));
```

LazyObectLinkingLayer is updated to use this new method, but the LLVM-IR
level CompileOnDemandLayer will continue to use LazyCallThroughManager
and OrcABISupport until the new system supports a wider range of
architectures and ABIs.

The llvm-jitlink utility's -lazy option now uses the new scheme. Since
it depends on the ORC runtime, the lazy-link.ll testcase and associated
helpers are moved to the ORC runtime.
MaskRay pushed a commit that referenced this pull request Dec 10, 2024
The Clang binary (and any binary linking Clang as a library), when built
using PIE, ends up with a pretty shocking number of dynamic relocations
to apply to the executable image: roughly 400k.

Each of these takes up binary space in the executable, and perhaps most
interestingly takes start-up time to apply the relocations.

The largest pattern I identified were the strings used to describe
target builtins. The addresses of these string literals were stored into
huge arrays, each one requiring a dynamic relocation. The way to avoid
this is to design the target builtins to use a single large table of
strings and offsets within the table for the individual strings. This
switches the builtin management to such a scheme.

This saves over 100k dynamic relocations by my measurement, an over 25%
reduction. Just looking at byte size improvements, using the `bloaty`
tool to compare a newly built `clang` binary to an old one:

```
    FILE SIZE        VM SIZE
 --------------  --------------
  +1.4%  +653Ki  +1.4%  +653Ki    .rodata
  +0.0%    +960  +0.0%    +960    .text
  +0.0%    +197  +0.0%    +197    .dynstr
  +0.0%    +184  +0.0%    +184    .eh_frame
  +0.0%     +96  +0.0%     +96    .dynsym
  +0.0%     +40  +0.0%     +40    .eh_frame_hdr
  +114%     +32  [ = ]       0    [Unmapped]
  +0.0%     +20  +0.0%     +20    .gnu.hash
  +0.0%      +8  +0.0%      +8    .gnu.version
  +0.9%      +7  +0.9%      +7    [LOAD #2 [R]]
  [ = ]       0 -75.4% -3.00Ki    .relro_padding
 -16.1%  -802Ki -16.1%  -802Ki    .data.rel.ro
 -27.3% -2.52Mi -27.3% -2.52Mi    .rela.dyn
  -1.6% -2.66Mi  -1.6% -2.66Mi    TOTAL
```

We get a 16% reduction in the `.data.rel.ro` section, and nearly 30%
reduction in `.rela.dyn` where those reloctaions are stored.

This is also visible in my benchmarking of binary start-up overhead at
least:

```
Benchmark 1: ./old_clang --version
  Time (mean ± σ):      17.6 ms ±   1.5 ms    [User: 4.1 ms, System: 13.3 ms]
  Range (min … max):    14.2 ms …  22.8 ms    162 runs

Benchmark 2: ./new_clang --version
  Time (mean ± σ):      15.5 ms ±   1.4 ms    [User: 3.6 ms, System: 11.8 ms]
  Range (min … max):    12.4 ms …  20.3 ms    216 runs

Summary
  './new_clang --version' ran
    1.13 ± 0.14 times faster than './old_clang --version'
```

We get about 2ms faster `--version` runs. While there is a lot of noise
in binary execution time, this delta is pretty consistent, and
represents over 10% improvement. This is particularly interesting to me
because for very short source files, repeatedly starting the `clang`
binary is actually the dominant cost. For example, `configure` scripts
running against the `clang` compiler are slow in large part because of
binary start up time, not the time to process the actual inputs to the
compiler.

----

This PR implements the string tables using `constexpr` code and the
existing macro system. I understand that the builtins are moving towards
a TableGen model, and if complete that would provide more options for
modeling this. Unfortunately, that migration isn't complete, and even
the parts that are migrated still rely on the ability to break out of
the TableGen model and directly expand an X-macro style `BUILTIN(...)`
textually. I looked at trying to complete the move to TableGen, but it
would both require the difficult migration of the remaining targets, and
solving some tricky problems with how to move away from any macro-based
expansion.

I was also able to find a reasonably clean and effective way of doing
this with the existing macros and some `constexpr` code that I think is
clean enough to be a pretty good intermediate state, and maybe give a
good target for the eventual TableGen solution. I was also able to
factor the macros into set of consistent patterns that avoids a
significant regression in overall boilerplate.
MaskRay pushed a commit that referenced this pull request Jan 25, 2025
llvm#123877)

Reverts llvm#122811 due to buildbot breakage e.g.,
https://lab.llvm.org/buildbot/#/builders/52/builds/5421/steps/11/logs/stdio

ASan output from local re-run:
```
==2780289==ERROR: AddressSanitizer: use-after-poison on address 0x7e0b87e28d28 at pc 0x55a979a99e7e bp 0x7ffe4b18f0b0 sp 0x7ffe4b18f0a8
READ of size 1 at 0x7e0b87e28d28 thread T0
    #0 0x55a979a99e7d in getStorageClass /usr/local/google/home/thurston/buildbot_repro/llvm-project/llvm/include/llvm/Object/COFF.h:344
    #1 0x55a979a99e7d in isSectionDefinition /usr/local/google/home/thurston/buildbot_repro/llvm-project/llvm/include/llvm/Object/COFF.h:429:9
    #2 0x55a979a99e7d in getSymbols /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/COFF/LLDMapFile.cpp:54:42
    #3 0x55a979a99e7d in lld::coff::writeLLDMapFile(lld::coff::COFFLinkerContext const&) /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/COFF/LLDMapFile.cpp:103:40
    #4 0x55a979a16879 in (anonymous namespace)::Writer::run() /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/COFF/Writer.cpp:810:3
    #5 0x55a979a00aac in lld::coff::writeResult(lld::coff::COFFLinkerContext&) /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/COFF/Writer.cpp:354:15
    llvm#6 0x55a97985f7ed in lld::coff::LinkerDriver::linkerMain(llvm::ArrayRef<char const*>) /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/COFF/Driver.cpp:2826:3
    llvm#7 0x55a97984cdd3 in lld::coff::link(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, bool, bool) /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/COFF/Driver.cpp:97:15
    llvm#8 0x55a9797f9793 in lld::unsafeLldMain(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, llvm::ArrayRef<lld::DriverDef>, bool) /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/Common/DriverDispatcher.cpp:163:12
    llvm#9 0x55a9797fa3b6 in operator() /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/Common/DriverDispatcher.cpp:188:15
    llvm#10 0x55a9797fa3b6 in void llvm::function_ref<void ()>::callback_fn<lld::lldMain(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, llvm::ArrayRef<lld::DriverDef>)::$_0>(long) /usr/local/google/home/thurston/buildbot_repro/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:46:12
    llvm#11 0x55a97966cb93 in operator() /usr/local/google/home/thurston/buildbot_repro/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:69:12
    llvm#12 0x55a97966cb93 in llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) /usr/local/google/home/thurston/buildbot_repro/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:426:3
    llvm#13 0x55a9797f9dc3 in lld::lldMain(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&, llvm::ArrayRef<lld::DriverDef>) /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/Common/DriverDispatcher.cpp:187:14
    llvm#14 0x55a979627512 in lld_main(int, char**, llvm::ToolContext const&) /usr/local/google/home/thurston/buildbot_repro/llvm-project/lld/tools/lld/lld.cpp:103:14
    llvm#15 0x55a979628731 in main /usr/local/google/home/thurston/buildbot_repro/llvm_build_asan/tools/lld/tools/lld/lld-driver.cpp:17:10
    llvm#16 0x7ffb8b202c89 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    llvm#17 0x7ffb8b202d44 in __libc_start_main csu/../csu/libc-start.c:360:3
    llvm#18 0x55a97953ef60 in _start (/usr/local/google/home/thurston/buildbot_repro/llvm_build_asan/bin/lld+0x8fd1f60)
```
MaskRay pushed a commit that referenced this pull request Mar 10, 2025
When compiling VLS SVE, the compiler often replaces VL-based offsets
with immediate-based ones. This leads to a mismatch in the allowed
addressing modes due to SVE loads/stores generally expecting immediate
offsets relative to VL. For example, given:
```c

svfloat64_t foo(const double *x) {
  svbool_t pg = svptrue_b64();
  return svld1_f64(pg, x+svcntd());
}
```

When compiled with `-msve-vector-bits=128`, we currently generate:
```gas
foo:
        ptrue   p0.d
        mov     x8, #2
        ld1d    { z0.d }, p0/z, [x0, x8, lsl #3]
        ret
```

Instead, we could be generating:
```gas
foo:
        ldr     z0, [x0, #1, mul vl]
        ret
```

Likewise for other types, stores, and other VLS lengths.

This patch achieves the above by extending `SelectAddrModeIndexedSVE`
to let constants through when `vscale` is known.
MaskRay pushed a commit that referenced this pull request Mar 13, 2025
…1027)

No codegen regression on either target. The two builtin_ffs implied on
nvptx CSE away.

```
define internal i64 @__gpu_read_first_lane_u64(i64 noundef %__lane_mask, i64 noundef %__x) #2 {
entry:
  %shr = lshr i64 %__x, 32
  %conv = trunc nuw i64 %shr to i32
  %conv1 = trunc i64 %__x to i32
  %conv2 = trunc i64 %__lane_mask to i32
  %0 = tail call range(i32 0, 33) i32 @llvm.cttz.i32(i32 %conv2, i1 true)
  %iszero = icmp eq i32 %conv2, 0
  %sub = select i1 %iszero, i32 -1, i32 %0
  %1 = tail call i32 @llvm.nvvm.shfl.sync.idx.i32(i32 %conv2, i32 %conv, i32 %sub, i32 31)
  %conv4 = sext i32 %1 to i64
  %shl = shl nsw i64 %conv4, 32
  %2 = tail call i32 @llvm.nvvm.shfl.sync.idx.i32(i32 %conv2, i32 %conv1, i32 %sub, i32 31)
  %conv7 = zext i32 %2 to i64
  %or = or disjoint i64 %shl, %conv7
  ret i64 %or
}
; becomes

define internal i64 @__gpu_competing_read_first_lane_u64(i64 noundef %__lane_mask, i64 noundef %__x) #2 {
entry:
  %shr = lshr i64 %__x, 32
  %conv = trunc nuw i64 %shr to i32
  %conv1 = trunc i64 %__x to i32
  %conv.i = trunc i64 %__lane_mask to i32
  %0 = tail call range(i32 0, 33) i32 @llvm.cttz.i32(i32 %conv.i, i1 true)
  %iszero = icmp eq i32 %conv.i, 0
  %sub.i = select i1 %iszero, i32 -1, i32 %0
  %1 = tail call i32 @llvm.nvvm.shfl.sync.idx.i32(i32 %conv.i, i32 %conv, i32 %sub.i, i32 31)
  %conv4 = zext i32 %1 to i64
  %shl = shl nuw i64 %conv4, 32
  %2 = tail call i32 @llvm.nvvm.shfl.sync.idx.i32(i32 %conv.i, i32 %conv1, i32 %sub.i, i32 31)
  %conv7 = zext i32 %2 to i64
  %or = or disjoint i64 %shl, %conv7
  ret i64 %or
}
```

The sext vs zext difference is vaguely interesting but since the bits
are immediately discarded in either case it make no odds. The amdgcn one
doesn't need CSE, the readfirstlane function is a single call to an
intrinsic.

Drive by fix to __gpu_match_all_u32, it was calling first_lane_u64 and
could use first_lane_u32 instead. Added the missing call to gpuintrin.c
test case and a stray missing static as well.
MaskRay pushed a commit that referenced this pull request Mar 22, 2025
…too. (llvm#132267)

Observed in Wine when trying to intercept `ExitThread`, which forwards
to `ntdll.RtlExitUserThread`.

`gdb` interprets it as `xchg %ax,%ax`.
`llvm-mc` outputs simply `nop`.

```
==Asan-i386-calls-Dynamic-Test.exe==964==interception_win: unhandled instruction at 0x7be27cf0: 66 90 55 89 e5 56 50 8b
```

```
Wine-gdb> bt
#0  0x789a1766 in __interception::GetInstructionSize (address=<optimized out>, rel_offset=<optimized out>) at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/interception/interception_win.cpp:983
#1  0x789ab480 in __sanitizer::SharedPrintfCode(bool, char const*, char*) () at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_printf.cpp:311
#2  0x789a18e7 in __interception::OverrideFunctionWithHotPatch (old_func=2078440688, new_func=2023702608, orig_old_func=warning: (Internal error: pc 0x792f1a2c in read in CU, but not in symtab.)warning: (Error: pc 0x792f1a2c in address map, but not in symtab.)0x792f1a2c) at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/interception/interception_win.cpp:1118
#3  0x789a1f34 in __interception::OverrideFunction (old_func=2078440688, new_func=2023702608, orig_old_func=warning: (Internal error: pc 0x792f1a2c in read in CU, but not in symtab.)warning: (Error: pc 0x792f1a2c in address map, but not in symtab.)0x792f1a2c) at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/interception/interception_win.cpp:1224
#4  0x789a24ce in __interception::OverrideFunction (func_name=0x78a0bc43 <vtable for __asan::AsanThreadContext+1163> "ExitThread", new_func=2023702608, orig_old_func=warning: (Internal error: pc 0x792f1a2c in read in CU, but not in symtab.)warning: (Error: pc 0x792f1a2c in address map, but not in symtab.)0x792f1a2c)    at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/interception/interception_win.cpp:1369
#5  0x789f40ef in __asan::InitializePlatformInterceptors () at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/asan/asan_win.cpp:190
llvm#6  0x789e0c3c in __asan::InitializeAsanInterceptors () at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/asan/asan_interceptors.cpp:802
llvm#7  0x789ee6b5 in __asan::AsanInitInternal () at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/asan/asan_rtl.cpp:442
llvm#8  0x789eefb0 in __asan::AsanInitFromRtl () at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/asan/asan_rtl.cpp:522
llvm#9  __asan::AsanInitializer::AsanInitializer (this=<optimized out>) at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/asan/asan_rtl.cpp:542
llvm#10 __cxx_global_var_init () at C:/llvm-mingw/llvm-mingw/llvm-project/compiler-rt/lib/asan/asan_rtl.cpp:546
...
Wine-gdb> disassemble /r 2078440688,2078440688+20
Dump of assembler code from 0x7be27cf0 to 0x7be27d04:
   0x7be27cf0 <_RtlExitUserThread@4+0>: 66 90                   xchg   %ax,%ax
...
```
MaskRay pushed a commit that referenced this pull request Apr 3, 2025
…#134130)

This should fix failures caused by
llvm#133967
Attn: @sarnex
Thanks

Signed-off-by: Arvind Sudarsanam <arvind.sudarsanam@intel.com>
MaskRay pushed a commit that referenced this pull request Apr 6, 2025
…d A520 (llvm#132246)

Inefficient SVE codegen occurs on at least two in-order cores,
those being Cortex-A510 and Cortex-A520. For example a simple vector
add

```
void foo(float a, float b, float dst, unsigned n) {
    for (unsigned i = 0; i < n; ++i)
        dst[i] = a[i] + b[i];
}
```

Vectorizes the inner loop into the following interleaved sequence
of instructions.

```
        add     x12, x1, x10
        ld1b    { z0.b }, p0/z, [x1, x10]
        add     x13, x2, x10
        ld1b    { z1.b }, p0/z, [x2, x10]
        ldr     z2, [x12, #1, mul vl]
        ldr     z3, [x13, #1, mul vl]
        dech    x11
        add     x12, x0, x10
        fadd    z0.s, z1.s, z0.s
        fadd    z1.s, z3.s, z2.s
        st1b    { z0.b }, p0, [x0, x10]
        addvl   x10, x10, #2
        str     z1, [x12, #1, mul vl]
```

By adjusting the target features to prefer fixed over scalable if the
cost is equal we get the following vectorized loop.

```
         ldp q0, q3, [x11, #-16]
         subs    x13, x13, llvm#8
         ldp q1, q2, [x10, #-16]
         add x10, x10, llvm#32
         add x11, x11, llvm#32
         fadd    v0.4s, v1.4s, v0.4s
         fadd    v1.4s, v2.4s, v3.4s
         stp q0, q1, [x12, #-16]
         add x12, x12, llvm#32
```

Which is more efficient.
MaskRay pushed a commit that referenced this pull request Apr 14, 2025
… A510/A520 (llvm#134606)

Recommit. This work was done by llvm#132246 but failed buildbots due to the
test introduced needing updates

Inefficient SVE codegen occurs on at least two in-order cores, those
being Cortex-A510 and Cortex-A520. For example a simple vector add

```
void foo(float a, float b, float dst, unsigned n) {
    for (unsigned i = 0; i < n; ++i)
        dst[i] = a[i] + b[i];
}
```

Vectorizes the inner loop into the following interleaved sequence of
instructions.

```
        add     x12, x1, x10
        ld1b    { z0.b }, p0/z, [x1, x10]
        add     x13, x2, x10
        ld1b    { z1.b }, p0/z, [x2, x10]
        ldr     z2, [x12, #1, mul vl]
        ldr     z3, [x13, #1, mul vl]
        dech    x11
        add     x12, x0, x10
        fadd    z0.s, z1.s, z0.s
        fadd    z1.s, z3.s, z2.s
        st1b    { z0.b }, p0, [x0, x10]
        addvl   x10, x10, #2
        str     z1, [x12, #1, mul vl]
```

By adjusting the target features to prefer fixed over scalable if the
cost is equal we get the following vectorized loop.

```
         ldp q0, q3, [x11, #-16]
         subs    x13, x13, llvm#8
         ldp q1, q2, [x10, #-16]
         add x10, x10, llvm#32
         add x11, x11, llvm#32
         fadd    v0.4s, v1.4s, v0.4s
         fadd    v1.4s, v2.4s, v3.4s
         stp q0, q1, [x12, #-16]
         add x12, x12, llvm#32
```

Which is more efficient.
MaskRay pushed a commit that referenced this pull request Apr 14, 2025
…ctor-bits=128." (llvm#134997)

Reverts llvm#134068

Caused a stage 2 build failure:
https://lab.llvm.org/buildbot/#/builders/41/builds/6016

```
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/Caching.cpp.o 
/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage1.install/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/lib/Support -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/llvm/lib/Support -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/include -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/llvm/include -mcpu=neoverse-512tvb -mllvm -scalable-vectorization=preferred -mllvm -treat-scalable-fixed-error-as-warning=false -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Werror=global-constructors -O3 -DNDEBUG -std=c++17 -UNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/Caching.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/Caching.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/Caching.cpp.o -c /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/llvm/lib/Support/Caching.cpp
Opcode has unknown scale!
UNREACHABLE executed at ../llvm/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp:4530!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage1.install/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/lib/Support -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/llvm/lib/Support -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/include -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/llvm/include -mcpu=neoverse-512tvb -mllvm -scalable-vectorization=preferred -mllvm -treat-scalable-fixed-error-as-warning=false -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Werror=global-constructors -O3 -DNDEBUG -std=c++17 -UNDEBUG -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/Caching.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/Caching.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/Caching.cpp.o -c /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/llvm/lib/Support/Caching.cpp
1.	<eof> parser at end of file
2.	Code generation
3.	Running pass 'Function Pass Manager' on module '/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/llvm/lib/Support/Caching.cpp'.
4.	Running pass 'AArch64 load / store optimization pass' on function '@"_ZNSt17_Function_handlerIFN4llvm8ExpectedISt8functionIFNS1_ISt10unique_ptrINS0_16CachedFileStreamESt14default_deleteIS4_EEEEjRKNS0_5TwineEEEEEjNS0_9StringRefESB_EZNS0_10localCacheESB_SB_SB_S2_IFvjSB_S3_INS0_12MemoryBufferES5_ISH_EEEEE3$_0E9_M_invokeERKSt9_Any_dataOjOSF_SB_"'
 #0 0x0000b6eae9b67bf0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage1.install/bin/clang+++0x81c7bf0)
 #1 0x0000b6eae9b65aec llvm::sys::RunSignalHandlers() (/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage1.install/bin/clang+++0x81c5aec)
 #2 0x0000b6eae9acd5f4 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x0000f16c1aff28f8 (linux-vdso.so.1+0x8f8)
 #4 0x0000f16c1aacf1f0 __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #5 0x0000f16c1aa8a67c gsignal ./signal/../sysdeps/posix/raise.c:27:6
 llvm#6 0x0000f16c1aa77130 abort ./stdlib/abort.c:81:7
 llvm#7 0x0000b6eae9ad6628 (/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage1.install/bin/clang+++0x8136628)
 llvm#8 0x0000b6eae72e95a8 (/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage1.install/bin/clang+++0x59495a8)
 llvm#9 0x0000b6eae74ca9a8 (anonymous namespace)::AArch64LoadStoreOpt::findMatchingInsn(llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>, (anonymous namespace)::LdStPairFlags&, unsigned int, bool) AArch64LoadStoreOptimizer.cpp:0:0
llvm#10 0x0000b6eae74c85a8 (anonymous namespace)::AArch64LoadStoreOpt::tryToPairLdStInst(llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&) AArch64LoadStoreOptimizer.cpp:0:0
llvm#11 0x0000b6eae74c624c (anonymous namespace)::AArch64LoadStoreOpt::optimizeBlock(llvm::MachineBasicBlock&, bool) AArch64LoadStoreOptimizer.cpp:0:0
llvm#12 0x0000b6eae74c429c (anonymous namespace)::AArch64LoadStoreOpt::runOnMachineFunction(llvm::MachineFunction&) AArch64LoadStoreOptimizer.cpp:0:0
```
MaskRay pushed a commit that referenced this pull request Apr 14, 2025
…vailable (llvm#135343)

When a frame is inlined, LLDB will display its name in backtraces as
follows:
```
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.3
  * frame #0: 0x0000000100000398 a.out`func() [inlined] baz(x=10) at inline.cpp:1:42
    frame #1: 0x0000000100000398 a.out`func() [inlined] bar() at inline.cpp:2:37
    frame #2: 0x0000000100000398 a.out`func() at inline.cpp:4:15
    frame #3: 0x00000001000003c0 a.out`main at inline.cpp:7:5
    frame #4: 0x000000026eb29ab8 dyld`start + 6812
```
The longer the names get the more confusing this gets because the first
function name that appears is the parent frame. My assumption (which may
need some more surveying) is that for the majority of cases we only care
about the actual frame name (not the parent). So this patch removes all
the special logic that prints the parent frame.

Another quirk of the current format is that the inlined frame name does
not abide by the `${function.name-XXX}` format variables. We always just
print the raw demangled name. With this patch, we would format the
inlined frame name according to the `frame-format` setting (see the
test-cases).

If we really want to have the `parentFrame [inlined] inlinedFrame`
format, we could expose it through a new `frame-format` variable (e..g.,
`${function.inlined-at-name}` and let the user decide where to place
things.
MaskRay pushed a commit that referenced this pull request May 15, 2025
… `getForwardSlice` matchers (llvm#115670)

Improve mlir-query tool by implementing `getBackwardSlice` and
`getForwardSlice` matchers. As an addition `SetQuery` also needed to be
added to enable custom configuration for each query. e.g: `inclusive`,
`omitUsesFromAbove`, `omitBlockArguments`.

Note: backwardSlice and forwardSlice algoritms are the same as the ones
in `mlir/lib/Analysis/SliceAnalysis.cpp`
Example of current matcher. The query was made to the file:
`mlir/test/mlir-query/complex-test.mlir`

```mlir
./mlir-query /home/dbudii/personal/llvm-project/mlir/test/mlir-query/complex-test.mlir -c "match getDefinitions(hasOpName(\"arith.add
f\"),2)"

Match #1:

/home/dbudii/personal/llvm-project/mlir/test/mlir-query/complex-test.mlir:5:8:
  %0 = linalg.generic {indexing_maps = [#map, #map], iterator_types = ["parallel", "parallel"]} ins(%arg0 : tensor<5x5xf32>) outs(%arg1 : tensor<5x5xf32>) {
       ^
/home/dbudii/personal/llvm-project/mlir/test/mlir-query/complex-test.mlir:7:10: note: "root" binds here
    %2 = arith.addf %in, %in : f32
         ^
Match #2:

/home/dbudii/personal/llvm-project/mlir/test/mlir-query/complex-test.mlir:10:16:
  %collapsed = tensor.collapse_shape %0 [[0, 1]] : tensor<5x5xf32> into tensor<25xf32>
               ^
/home/dbudii/personal/llvm-project/mlir/test/mlir-query/complex-test.mlir:13:11:
    %c2 = arith.constant 2 : index
          ^
/home/dbudii/personal/llvm-project/mlir/test/mlir-query/complex-test.mlir:14:18:
    %extracted = tensor.extract %collapsed[%c2] : tensor<25xf32>
                 ^
/home/dbudii/personal/llvm-project/mlir/test/mlir-query/complex-test.mlir:15:10: note: "root" binds here
    %2 = arith.addf %extracted, %extracted : f32
         ^
2 matches.
```
MaskRay pushed a commit that referenced this pull request Jun 5, 2025
Fixes llvm#123300

What is seen 
```
clang-repl> int x = 42;
clang-repl> auto capture = [&]() { return x * 2; };
In file included from <<< inputs >>>:1:
input_line_4:1:17: error: non-local lambda expression cannot have a capture-default
    1 | auto capture = [&]() { return x * 2; };
      |                 ^
zsh: segmentation fault  clang-repl --Xcc="-v"

(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x8)
  * frame #0: 0x0000000107b4f8b8 libclang-cpp.19.1.dylib`clang::IncrementalParser::CleanUpPTU(clang::PartialTranslationUnit&) + 988
    frame #1: 0x0000000107b4f1b4 libclang-cpp.19.1.dylib`clang::IncrementalParser::ParseOrWrapTopLevelDecl() + 416
    frame #2: 0x0000000107b4fb94 libclang-cpp.19.1.dylib`clang::IncrementalParser::Parse(llvm::StringRef) + 612
    frame #3: 0x0000000107b52fec libclang-cpp.19.1.dylib`clang::Interpreter::ParseAndExecute(llvm::StringRef, clang::Value*) + 180
    frame #4: 0x0000000100003498 clang-repl`main + 3560
    frame #5: 0x000000018d39a0e0 dyld`start + 2360
```

Though the error is justified, we shouldn't be interested in exiting
through a segfault in such cases.

The issue is that empty named decls weren't being taken care of
resulting into this assert


https://github.com/llvm/llvm-project/blob/c1a229252617ed58f943bf3f4698bd8204ee0f04/clang/include/clang/AST/DeclarationName.h#L503

Can also be seen when the example is attempted through xeus-cpp-lite.


![image](https://github.com/user-attachments/assets/9b0e6ead-138e-4b06-9ad9-fcb9f8d5bf6e)
MaskRay pushed a commit that referenced this pull request Jun 11, 2025
…142952)

This was removed in llvm#135343 in
favour of making it a format variable, which we do here. This follows
the precedent of the `[opt]` and `[artificial]` markers.

Before:
```
 thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.2
 * frame #0: 0x000000010000037c a.out`inlined1() at inline.cpp:4:3
   frame #1: 0x000000010000037c a.out`regular() at inline.cpp:6:17
   frame #2: 0x00000001000003b8 a.out`inlined2() at inline.cpp:7:43
   frame #3: 0x00000001000003b4 a.out`main at inline.cpp:10:3
   frame #4: 0x0000000186345be4 dyld`start + 7040
```

After (note the `[inlined]` markers):
```
thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.2
* frame #0: 0x000000010000037c a.out`inlined1() at inline.cpp:4:3 [inlined]
  frame #1: 0x000000010000037c a.out`regular() at inline.cpp:6:17
  frame #2: 0x00000001000003b8 a.out`inlined2() at inline.cpp:7:43 [inlined]
  frame #3: 0x00000001000003b4 a.out`main at inline.cpp:10:3
  frame #4: 0x0000000186345be4 dyld`start + 7040
```

rdar://152642178
MaskRay pushed a commit that referenced this pull request Jun 27, 2025
LLVM prevents the sm_32_intrinsics.hpp header from being included with a
#define SM_32_INTRINSICS_HPP. It also provides drop-in replacements of
the functions defined in the CUDA header.

One issue is that some intrinsics were added after the replacement was
written, and thus have no replacement, breaking code that calls them
(Raft is one example).

This commit backport the code from sm_32_intrinsics.hpp for the missing
intrinsics.

This is the second try after PR llvm#143664 broke tests.
MaskRay pushed a commit that referenced this pull request Jun 29, 2025
The function already exposes a work list to avoid deep recursion, this
commit starts utilizing it in a helper that could also lead to a deep
recursion.

We have observed this crash on `clang/test/C/C99/n590.c` with our
internal builds that enable aggressive optimizations and hit the limit
earlier than default release builds of Clang.

See the added test for an example with a deeper recursion that used to
crash in upstream Clang before this change with the following stack
trace:

```
  #0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/local/google/home/ibiryukov/code/llvm-project/llvm/lib/Support/Unix/Signals.inc:804:13
  #1 llvm::sys::RunSignalHandlers() /usr/local/google/home/ibiryukov/code/llvm-project/llvm/lib/Support/Signals.cpp:106:18
  #2 SignalHandler(int, siginfo_t*, void*) /usr/local/google/home/ibiryukov/code/llvm-project/llvm/lib/Support/Unix/Signals.inc:0:3
  #3 (/lib/x86_64-linux-gnu/libc.so.6+0x3fdf0)
  #4 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12772:0
  #5 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
  llvm#6 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
  llvm#7 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
  llvm#8 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
  llvm#9 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#10 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
 llvm#11 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
 llvm#12 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#13 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
 llvm#14 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
 llvm#15 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#16 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
 llvm#17 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
 llvm#18 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#19 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
... 700+ more stack frames.
```
MaskRay pushed a commit that referenced this pull request Jul 16, 2025
Fix unnecessary conversion of C-String to StringRef in the `Cmp` lambda
inside `lookupLLVMIntrinsicByName`. This both fixes an ASAN error in the
code that happens when the `Name` StringRef passed in is not a Null
terminated StringRef, and additionally can potentially speed up the code
as well by eliminating the unnecessary computation of string length
every time a C String is converted to StringRef in this code (It seems
practically this computation is eliminated in optimized builds, but this
will avoid it in O0 builds as well).

Added a unit test that demonstrates this issue by building LLVM with
these options:

```
CMAKE_BUILD_TYPE=Debug
LLVM_USE_SANITIZER=Address
LLVM_OPTIMIZE_SANITIZED_BUILDS=OFF
```

The error reported is as follows:

```
==462665==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x5030000391a2 at pc 0x56525cc30bbf bp 0x7fff9e4ccc60 sp 0x7fff9e4cc428
READ of size 19 at 0x5030000391a2 thread T0
    #0 0x56525cc30bbe in strlen (upstream-llvm-second/llvm-project/build/unittests/IR/IRTests+0x713bbe) (BuildId: 0651acf1e582a4d2)
    #1 0x7f8ff22ad334 in std::char_traits<char>::length(char const*) /usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/char_traits.h:399:9
    #2 0x7f8ff22a34a0 in llvm::StringRef::StringRef(char const*) /home/rjoshi/upstream-llvm-second/llvm-project/llvm/include/llvm/ADT/StringRef.h:96:33
    #3 0x7f8ff28ca184 in _ZZL25lookupLLVMIntrinsicByNameN4llvm8ArrayRefIjEENS_9StringRefES2_ENK3$_0clIjPKcEEDaT_T0_ upstream-llvm-second/llvm-project/llvm/lib/IR/Intrinsics.cpp:673:18
```
MaskRay pushed a commit that referenced this pull request Jul 29, 2025
Tracked at llvm#112294

This patch implements from [basic.link]p14 to [basic.link]p18 partially.

The explicitly missing parts are:
- Anything related to specializations.
- Decide if a pointer is associated with a TU-local value at compile
  time.
- [basic.link]p15.1.2 to decide if a type is TU-local.
- Diagnose if TU-local functions from other TU are collected to the
  overload set. See [basic.link]p19, the call to 'h(N::A{});' in
  translation unit #2

There should be other implicitly missing parts as the wording uses
"names" briefly several times. But to implement this precisely, we have
to visit the whole AST, including Decls, Expression and Types, which may
be harder to implement and be more time-consuming for compilation time.
So I choose to implement the common parts.

It won't be too bad to miss some cases since we DIDN'T do any such
checks in the past 3 years. Any new check is an improvement. Given
modules have been basically available since clang15 without such checks,
it will be user unfriendly if we give a hard error now. And there are
a lot of cases which violating the rule actually just fine. So I decide
to emit it as warnings instead of hard errors.
MaskRay pushed a commit that referenced this pull request Jul 31, 2025
Extend support in LLDB for WebAssembly. This PR adds a new Process
plugin (ProcessWasm) that extends ProcessGDBRemote for WebAssembly
targets. It adds support for WebAssembly's memory model with separate
address spaces, and the ability to fetch the call stack from the
WebAssembly runtime.

I have tested this change with the WebAssembly Micro Runtime (WAMR,
https://github.com/bytecodealliance/wasm-micro-runtime) which implements
a GDB debug stub and supports the qWasmCallStack packet.

```
(lldb) process connect --plugin wasm connect://localhost:4567
Process 1 stopped
* thread #1, name = 'nobody', stop reason = trace
    frame #0: 0x40000000000001ad
wasm32_args.wasm`main:
->  0x40000000000001ad <+3>:  global.get 0
    0x40000000000001b3 <+9>:  i32.const 16
    0x40000000000001b5 <+11>: i32.sub
    0x40000000000001b6 <+12>: local.set 0
(lldb) b add
Breakpoint 1: where = wasm32_args.wasm`add + 28 at test.c:4:12, address = 0x400000000000019c
(lldb) c
Process 1 resuming
Process 1 stopped
* thread #1, name = 'nobody', stop reason = breakpoint 1.1
    frame #0: 0x400000000000019c wasm32_args.wasm`add(a=<unavailable>, b=<unavailable>) at test.c:4:12
   1    int
   2    add(int a, int b)
   3    {
-> 4        return a + b;
   5    }
   6
   7    int
(lldb) bt
* thread #1, name = 'nobody', stop reason = breakpoint 1.1
  * frame #0: 0x400000000000019c wasm32_args.wasm`add(a=<unavailable>, b=<unavailable>) at test.c:4:12
    frame #1: 0x40000000000001e5 wasm32_args.wasm`main at test.c:12:12
    frame #2: 0x40000000000001fe wasm32_args.wasm
```

This PR is based on an unmerged patch from Paolo Severini:
https://reviews.llvm.org/D78801. I intentionally stuck to the
foundations to keep this PR small. I have more PRs in the pipeline to
support the other features/packets.

My motivation for supporting Wasm is to support debugging Swift compiled
to WebAssembly:
https://www.swift.org/documentation/articles/wasm-getting-started.html
MaskRay pushed a commit that referenced this pull request Aug 4, 2025
Pointers and GEP are untyped. SPIR-V required structured OpAccessChain.
This means the backend will have to determine a good way to retrieve the
structured access from an untyped GEP. This is not a trivial problem,
and needs to be addressed to have a robust compiler.

The issue is other workstreams relies on the access chain deduction to
work. So we have 2 options:
 - pause all dependent work until we have a good chain deduction.
- submit this limited fix to we can work on both this and other features
in parallel.

Choice we want to make is #2: submitting this **knowing this is not a
good** fix. It only increase the number of patterns we can work with,
thus allowing others to continue working on other parts of the backend.

This patch as-is has many limitations:
- If cannot robustly determine the depth of the structured access from a
GEP. Fixing this would require looking ahead at the full GEP chain.
- It cannot always figure out the correct access indices, especially
with dynamic indices. This will require frontend collaboration.

Because we know this is a temporary hack, this patch only impacts the
logical SPIR-V target. Physical SPIR-V, which can rely on pointer cast
remains on the old method.

Related to llvm#145002
MaskRay pushed a commit that referenced this pull request Aug 15, 2025
…lvm#152156)

With this new A320 in-order core, we follow adding the
FeatureUseFixedOverScalableIfEqualCost feature to A510 and A520
(llvm#132246), which reaps the same code generation benefits of preferring
fixed over scalable when the cost is equal.

So when we have:
```
void foo(float* a, float* b, float* dst, unsigned n) {
    for (unsigned i = 0; i < n; ++i)
        dst[i] = a[i] + b[i];
}
```

When compiling without the feature enabled, we get:
```
...
    ld1b    { z0.b }, p0/z, [x0, x10]
    ld1b    { z2.b }, p0/z, [x1, x10]
    add     x12, x0, x10
    ldr     z1, [x12, #1, mul vl]
    add     x12, x1, x10
    ldr     z3, [x12, #1, mul vl]
    fadd    z0.s, z2.s, z0.s
    add     x12, x2, x10
    fadd    z1.s, z3.s, z1.s
    dech    x11
    st1b    { z0.b }, p0, [x2, x10]
    incb    x10, all, mul #2
    str     z1, [x12, #1, mul vl]
...
```

When compiling with, we get:
```
...
  	ldp	    q0, q1, [x12, #-16]
	ldp	    q2, q3, [x11, #-16]
	subs	x13, x13, llvm#8
	fadd	v0.4s, v2.4s, v0.4s
	fadd	v1.4s, v3.4s, v1.4s
	add	    x11, x11, llvm#32
	add	    x12, x12, llvm#32
	stp	    q0, q1, [x10, #-16]
	add	    x10, x10, llvm#32

...
```
MaskRay pushed a commit that referenced this pull request Aug 15, 2025
## Problem

When the new setting

```
set target.parallel-module-load true
```
was added, lldb began fetching modules from the devices from multiple
threads simultaneously. This caused crashes of lldb when debugging on
android devices.

The top of the stack in the crash look something like this:
```
#0 0x0000555aaf2b27fe llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/llvm/bin/lldb-dap+0xb87fe)
 #1 0x0000555aaf2b0a99 llvm::sys::RunSignalHandlers() (/opt/llvm/bin/lldb-dap+0xb6a99)
 #2 0x0000555aaf2b2fda SignalHandler(int, siginfo_t*, void*) (/opt/llvm/bin/lldb-dap+0xb8fda)
 #3 0x00007f9c02444560 __restore_rt /home/engshare/third-party2/glibc/2.34/src/glibc-2.34/signal/../sysdeps/unix/sysv/linux/libc_sigaction.c:13:0
 #4 0x00007f9c04ea7707 lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Status*) (usr/bin/../lib/liblldb.so.15+0x22a7707)
 #5 0x00007f9c04ea5b41 lldb_private::ConnectionFileDescriptor::~ConnectionFileDescriptor() (usr/bin/../lib/liblldb.so.15+0x22a5b41)
 llvm#6 0x00007f9c04ea5c1e lldb_private::ConnectionFileDescriptor::~ConnectionFileDescriptor() (usr/bin/../lib/liblldb.so.15+0x22a5c1e)
 llvm#7 0x00007f9c052916ff lldb_private::platform_android::AdbClient::SyncService::Stat(lldb_private::FileSpec const&, unsigned int&, unsigned int&, unsigned int&) (usr/bin/../lib/liblldb.so.15+0x26916ff)
 llvm#8 0x00007f9c0528b9dc lldb_private::platform_android::PlatformAndroid::GetFile(lldb_private::FileSpec const&, lldb_private::FileSpec const&) (usr/bin/../lib/liblldb.so.15+0x268b9dc)
```
Our workaround was to set `set target.parallel-module-load ` to `false`
to avoid the crash.

## Background

PlatformAndroid creates two different classes with one stateful adb
connection shared between the two -- one through AdbClient and another
through AdbClient::SyncService. The connection management and state is
complex, and seems to be responsible for the segfault we are seeing. The
AdbClient code resets these connections at times, and re-establishes
connections if they are not active. Similarly, PlatformAndroid caches
its SyncService, which uses an AdbClient class, but the SyncService puts
its connection into a different 'sync' state that is incompatible with a
standard connection.

## Changes in this diff

* This diff refactors the code to (hopefully) have clearer ownership of
the connection, clearer separation of AdbClient and SyncService by
making a new class for clearer separations of concerns, called
AdbSyncService.
* New unit tests are added
* Additional logs were added (see
llvm#145382 (comment)
for details)
MaskRay pushed a commit that referenced this pull request Aug 15, 2025
…namic (llvm#153420)

Canonicalizing the following IR:

```
func.func @mul_zero_dynamic_nofold(%arg0: tensor<?x17xf32>) -> tensor<?x17xf32> {
  %0 = "tosa.const"() <{values = dense<0.000000e+00> : tensor<1x1xf32>}> : () -> tensor<1x1xf32>
  %1 = "tosa.const"() <{values = dense<0> : tensor<1xi8>}> : () -> tensor<1xi8>
  %2 = tosa.mul %arg0, %0, %1 : (tensor<?x17xf32>, tensor<1x1xf32>, tensor<1xi8>) -> tensor<?x17xf32>
  return %2 : tensor<?x17xf32>
}
```

resulted in a crash

```
#0 0x000056513187e8db backtrace (./build-release/bin/mlir-opt+0x9d698db)                                                                                                                                                                                                                                                                                                                   
 #1 0x0000565131b17737 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/llvm/lib/Support/Unix/Signals.inc:838:8                                                                                                                                                                                                                
 #2 0x0000565131b187f3 PrintStackTraceSignalHandler(void*) /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/llvm/lib/Support/Unix/Signals.inc:918:1                                                                                                                                                                                                                                
 #3 0x0000565131b18c30 llvm::sys::RunSignalHandlers() /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/llvm/lib/Support/Signals.cpp:105:18                                                                                                                                                                                                                                         
 #4 0x0000565131b18c30 SignalHandler(int, siginfo_t*, void*) /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/llvm/lib/Support/Unix/Signals.inc:409:3                                                                                                                                                                                                                              
 #5 0x00007f2e4165b050 (/lib/x86_64-linux-gnu/libc.so.6+0x3c050)                                                                                                                                                                                                                                                                                                                            
 llvm#6 0x00007f2e416a9eec __pthread_kill_implementation ./nptl/pthread_kill.c:44:76                                                                                                                                                                                                                                                                                                            
 llvm#7 0x00007f2e4165afb2 raise ./signal/../sysdeps/posix/raise.c:27:6                                                                                                                                                                                                                                                                                                                         
 llvm#8 0x00007f2e41645472 abort ./stdlib/abort.c:81:7                                                                                                                                                                                                                                                                                                                                          
 llvm#9 0x00007f2e41645395 _nl_load_domain ./intl/loadmsgcat.c:1177:9                                                                                                                                                                                                                                                                                                                           
llvm#10 0x00007f2e41653ec2 (/lib/x86_64-linux-gnu/libc.so.6+0x34ec2)                                                                                                                                                                                                                                                                                                                            
llvm#11 0x00005651443ec4ba mlir::DenseIntOrFPElementsAttr::getRaw(mlir::ShapedType, llvm::ArrayRef<char>) /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/mlir/lib/IR/BuiltinAttributes.cpp:1361:3                                                                                                                                                                                    
llvm#12 0x00005651443f1209 mlir::DenseElementsAttr::resizeSplat(mlir::ShapedType) /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/mlir/lib/IR/BuiltinAttributes.cpp:0:10                                                                                                                                                                                                              
llvm#13 0x000056513f76f2b6 mlir::tosa::MulOp::fold(mlir::tosa::MulOpGenericAdaptor<llvm::ArrayRef<mlir::Attribute>>) /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/mlir/lib/Dialect/Tosa/IR/TosaCanonicalizations.cpp:0:0
```

from the folder for `tosa::mul` since the zero value was being reshaped
to `?x17` size which isn't supported. AFAIK, `tosa.const` requires all
dimensions to be static. So in this case, the fix is to not to fold the
op.
MaskRay pushed a commit that referenced this pull request Aug 24, 2025
This can happen when JIT code is run, and we can't symbolize those
frames, but they should remain numbered in the stack. An example
spidermonkey trace:

```
    #0 0x564ac90fb80f  (/builds/worker/dist/bin/js+0x240e80f) (BuildId: 5d053c76aad4cfbd08259f8832e7ac78bbeeab58)
    #1 0x564ac9223a64  (/builds/worker/dist/bin/js+0x2536a64) (BuildId: 5d053c76aad4cfbd08259f8832e7ac78bbeeab58)
    #2 0x564ac922316f  (/builds/worker/dist/bin/js+0x253616f) (BuildId: 5d053c76aad4cfbd08259f8832e7ac78bbeeab58)
    #3 0x564ac9eac032  (/builds/worker/dist/bin/js+0x31bf032) (BuildId: 5d053c76aad4cfbd08259f8832e7ac78bbeeab58)
    #4 0x0dec477ca22e  (<unknown module>)
```

Without this change, the following symbolization is output:

```
    #0 0x55a6d72f980f in MOZ_CrashSequence /builds/worker/workspace/obj-build/dist/include/mozilla/Assertions.h:248:3
    #1 0x55a6d72f980f in Crash(JSContext*, unsigned int, JS::Value*) /builds/worker/checkouts/gecko/js/src/shell/js.cpp:4223:5
    #2 0x55a6d7421a64 in CallJSNative(JSContext*, bool (*)(JSContext*, unsigned int, JS::Value*), js::CallReason, JS::CallArgs const&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:501:13
    #3 0x55a6d742116f in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:597:12
    #4 0x55a6d80aa032 in js::jit::DoCallFallback(JSContext*, js::jit::BaselineFrame*, js::jit::ICFallbackStub*, unsigned int, JS::Value*, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/jit/BaselineIC.cpp:1705:10
    #4 0x2c803bd8f22e  (<unknown module>)
```

The last frame has a duplicate number. With this change the numbering is
correct:

```
    #0 0x5620c58ec80f in MOZ_CrashSequence /builds/worker/workspace/obj-build/dist/include/mozilla/Assertions.h:248:3
    #1 0x5620c58ec80f in Crash(JSContext*, unsigned int, JS::Value*) /builds/worker/checkouts/gecko/js/src/shell/js.cpp:4223:5
    #2 0x5620c5a14a64 in CallJSNative(JSContext*, bool (*)(JSContext*, unsigned int, JS::Value*), js::CallReason, JS::CallArgs const&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:501:13
    #3 0x5620c5a1416f in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:597:12
    #4 0x5620c669d032 in js::jit::DoCallFallback(JSContext*, js::jit::BaselineFrame*, js::jit::ICFallbackStub*, unsigned int, JS::Value*, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/jit/BaselineIC.cpp:1705:10
    #5 0x349f24c7022e  (<unknown module>)
```
MaskRay pushed a commit that referenced this pull request Sep 22, 2025
A few improvements to logging when lldb-dap is started in **Server
Mode** AND when the **`lldb-dap.logFolder`** setting is used (not
`lldb-dap.log-path`).

### Improvement #1
**Avoid the prompt of restarting the server when starting each debug
session.**

That prompt is caused by the combination of the following facts:
1. The log filename changes every time a new debug session is starting
(see
[here](https://github.com/llvm/llvm-project/blob/9d6062c490548a5e6fea103e010ab3c9bc73a86d/lldb/tools/lldb-dap/src-ts/logging.ts#L47))
2. The log filename is passed to the server via an environment variable
called "LLDBDAP_LOG" (see
[here](https://github.com/llvm/llvm-project/blob/9d6062c490548a5e6fea103e010ab3c9bc73a86d/lldb/tools/lldb-dap/src-ts/debug-adapter-factory.ts#L263-L269))
3. All environment variables are put into the "spawn info" variable (see
[here](https://github.com/llvm/llvm-project/blob/9d6062c490548a5e6fea103e010ab3c9bc73a86d/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts#L170-L172)).
4. The old and new "spawn info" are compared to decide if a prompt
should show (see
[here](https://github.com/llvm/llvm-project/blob/9d6062c490548a5e6fea103e010ab3c9bc73a86d/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts#L107-L110)).

The fix is to remove the "LLDBDAP_LOG" from the "spawn info" variable,
so that the same server can be reused if the log path is the only thing
that has changed.

### Improvement #2
**Avoid log file conflict when multiple users share a machine and start
server in the same second.**

The problem: If two users start lldb-dap server in the same second, they
will share the same log path. The first user will create the log file.
The second user will find that they cannot access the same file, so
their server will fail to start.

The fix is to add a part of the VS Code session ID to the log filename.

### Improvement #3
**Avoid restarting the server when the order of environment variables
changed.**

This is done by sorting the environment variables before putting them
into the "spawn info".
MaskRay pushed a commit that referenced this pull request Sep 24, 2025
Need this as `mlir/dialects/transform/smt.py` imports it:

```py
from .._transform_smt_extension_ops_gen import *
from .._transform_smt_extension_ops_gen import _Dialect
```
MaskRay pushed a commit that referenced this pull request Oct 13, 2025
A recent change adding a new sanitizer kind (via Sanitizers.def) was
reverted in c74fa20 ("Revert "[Clang][CodeGen] Introduce the
AllocToken SanitizerKind" (llvm#162413)"). The reason was this ASan report,
when running the test cases in
clang/test/Preprocessor/print-header-json.c:

```
==clang==483265==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7d82b97e8b58 at pc 0x562cd432231f bp 0x7fff3fad0850 sp 0x7fff3fad0848
READ of size 16 at 0x7d82b97e8b58 thread T0
    #0 0x562cd432231e in __copy_non_overlapping_range<const unsigned long *, const unsigned long *> zorg-test/libcxx_install_asan_ubsan/include/c++/v1/string:2144:38
    #1 0x562cd432231e in void std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>::__init_with_size[abi:nn220000]<unsigned long const*, unsigned long const*>(unsigned long const*, unsigned long const*, unsigned long) zorg-test/libcxx_install_asan_ubsan/include/c++/v1/string:2685:18
    #2 0x562cd41e2797 in __init<const unsigned long *, 0> zorg-test/libcxx_install_asan_ubsan/include/c++/v1/string:2673:3
    #3 0x562cd41e2797 in basic_string<const unsigned long *, 0> zorg-test/libcxx_install_asan_ubsan/include/c++/v1/string:1174:5
    #4 0x562cd41e2797 in clang::ASTReader::ReadString(llvm::SmallVectorImpl<unsigned long> const&, unsigned int&) clang/lib/Serialization/ASTReader.cpp:10171:15
    #5 0x562cd41fd89a in clang::ASTReader::ParseLanguageOptions(llvm::SmallVector<unsigned long, 64u> const&, llvm::StringRef, bool, clang::ASTReaderListener&, bool) clang/lib/Serialization/ASTReader.cpp:6475:28
    llvm#6 0x562cd41eea53 in clang::ASTReader::ReadOptionsBlock(llvm::BitstreamCursor&, llvm::StringRef, unsigned int, bool, clang::ASTReaderListener&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>&) clang/lib/Serialization/ASTReader.cpp:3069:11
    llvm#7 0x562cd4204ab8 in clang::ASTReader::ReadControlBlock(clang::serialization::ModuleFile&, llvm::SmallVectorImpl<clang::ASTReader::ImportedModule>&, clang::serialization::ModuleFile const*, unsigned int) clang/lib/Serialization/ASTReader.cpp:3249:15
    llvm#8 0x562cd42097d2 in clang::ASTReader::ReadASTCore(llvm::StringRef, clang::serialization::ModuleKind, clang::SourceLocation, clang::serialization::ModuleFile*, llvm::SmallVectorImpl<clang::ASTReader::ImportedModule>&, long, long, clang::ASTFileSignature, unsigned int) clang/lib/Serialization/ASTReader.cpp:5182:15
    llvm#9 0x562cd421ec77 in clang::ASTReader::ReadAST(llvm::StringRef, clang::serialization::ModuleKind, clang::SourceLocation, unsigned int, clang::serialization::ModuleFile**) clang/lib/Serialization/ASTReader.cpp:4828:11
    llvm#10 0x562cd3d07b74 in clang::CompilerInstance::findOrCompileModuleAndReadAST(llvm::StringRef, clang::SourceLocation, clang::SourceLocation, bool) clang/lib/Frontend/CompilerInstance.cpp:1805:27
    llvm#11 0x562cd3d0b2ef in clang::CompilerInstance::loadModule(clang::SourceLocation, llvm::ArrayRef<clang::IdentifierLoc>, clang::Module::NameVisibilityKind, bool) clang/lib/Frontend/CompilerInstance.cpp:1956:31
    llvm#12 0x562cdb04eb1c in clang::Preprocessor::HandleHeaderIncludeOrImport(clang::SourceLocation, clang::Token&, clang::Token&, clang::SourceLocation, clang::detail::SearchDirIteratorImpl<true>, clang::FileEntry const*) clang/lib/Lex/PPDirectives.cpp:2423:49
    llvm#13 0x562cdb042222 in clang::Preprocessor::HandleIncludeDirective(clang::SourceLocation, clang::Token&, clang::detail::SearchDirIteratorImpl<true>, clang::FileEntry const*) clang/lib/Lex/PPDirectives.cpp:2101:17
    llvm#14 0x562cdb043366 in clang::Preprocessor::HandleDirective(clang::Token&) clang/lib/Lex/PPDirectives.cpp:1338:14
    llvm#15 0x562cdafa84bc in clang::Lexer::LexTokenInternal(clang::Token&, bool) clang/lib/Lex/Lexer.cpp:4512:7
    llvm#16 0x562cdaf9f20b in clang::Lexer::Lex(clang::Token&) clang/lib/Lex/Lexer.cpp:3729:24
    llvm#17 0x562cdb0d4ffa in clang::Preprocessor::Lex(clang::Token&) clang/lib/Lex/Preprocessor.cpp:896:11
    llvm#18 0x562cd77da950 in clang::ParseAST(clang::Sema&, bool, bool) clang/lib/Parse/ParseAST.cpp:163:7
    [...]

0x7d82b97e8b58 is located 0 bytes after 3288-byte region [0x7d82b97e7e80,0x7d82b97e8b58)
allocated by thread T0 here:
    #0 0x562cca76f604 in malloc zorg-test/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:67:3
    #1 0x562cd1cce452 in safe_malloc llvm/include/llvm/Support/MemAlloc.h:26:18
    #2 0x562cd1cce452 in llvm::SmallVectorBase<unsigned int>::grow_pod(void*, unsigned long, unsigned long) llvm/lib/Support/SmallVector.cpp:151:15
    #3 0x562cdbe1768b in grow_pod llvm/include/llvm/ADT/SmallVector.h:139:11
    #4 0x562cdbe1768b in grow llvm/include/llvm/ADT/SmallVector.h:525:41
    #5 0x562cdbe1768b in reserve llvm/include/llvm/ADT/SmallVector.h:665:13
    llvm#6 0x562cdbe1768b in llvm::BitstreamCursor::readRecord(unsigned int, llvm::SmallVectorImpl<unsigned long>&, llvm::StringRef*) llvm/lib/Bitstream/Reader/BitstreamReader.cpp:230:10
    llvm#7 0x562cd41ee8ab in clang::ASTReader::ReadOptionsBlock(llvm::BitstreamCursor&, llvm::StringRef, unsigned int, bool, clang::ASTReaderListener&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>&) clang/lib/Serialization/ASTReader.cpp:3060:49
    llvm#8 0x562cd4204ab8 in clang::ASTReader::ReadControlBlock(clang::serialization::ModuleFile&, llvm::SmallVectorImpl<clang::ASTReader::ImportedModule>&, clang::serialization::ModuleFile const*, unsigned int) clang/lib/Serialization/ASTReader.cpp:3249:15
    llvm#9 0x562cd42097d2 in clang::ASTReader::ReadASTCore(llvm::StringRef, clang::serialization::ModuleKind, clang::SourceLocation, clang::serialization::ModuleFile*, llvm::SmallVectorImpl<clang::ASTReader::ImportedModule>&, long, long, clang::ASTFileSignature, unsigned int) clang/lib/Serialization/ASTReader.cpp:5182:15
    llvm#10 0x562cd421ec77 in clang::ASTReader::ReadAST(llvm::StringRef, clang::serialization::ModuleKind, clang::SourceLocation, unsigned int, clang::serialization::ModuleFile**) clang/lib/Serialization/ASTReader.cpp:4828:11
    llvm#11 0x562cd3d07b74 in clang::CompilerInstance::findOrCompileModuleAndReadAST(llvm::StringRef, clang::SourceLocation, clang::SourceLocation, bool) clang/lib/Frontend/CompilerInstance.cpp:1805:27
    llvm#12 0x562cd3d0b2ef in clang::CompilerInstance::loadModule(clang::SourceLocation, llvm::ArrayRef<clang::IdentifierLoc>, clang::Module::NameVisibilityKind, bool) clang/lib/Frontend/CompilerInstance.cpp:1956:31
    llvm#13 0x562cdb04eb1c in clang::Preprocessor::HandleHeaderIncludeOrImport(clang::SourceLocation, clang::Token&, clang::Token&, clang::SourceLocation, clang::detail::SearchDirIteratorImpl<true>, clang::FileEntry const*) clang/lib/Lex/PPDirectives.cpp:2423:49
    llvm#14 0x562cdb042222 in clang::Preprocessor::HandleIncludeDirective(clang::SourceLocation, clang::Token&, clang::detail::SearchDirIteratorImpl<true>, clang::FileEntry const*) clang/lib/Lex/PPDirectives.cpp:2101:17
    llvm#15 0x562cdb043366 in clang::Preprocessor::HandleDirective(clang::Token&) clang/lib/Lex/PPDirectives.cpp:1338:14
    llvm#16 0x562cdafa84bc in clang::Lexer::LexTokenInternal(clang::Token&, bool) clang/lib/Lex/Lexer.cpp:4512:7
    llvm#17 0x562cdaf9f20b in clang::Lexer::Lex(clang::Token&) clang/lib/Lex/Lexer.cpp:3729:24
    llvm#18 0x562cdb0d4ffa in clang::Preprocessor::Lex(clang::Token&) clang/lib/Lex/Preprocessor.cpp:896:11
    llvm#19 0x562cd77da950 in clang::ParseAST(clang::Sema&, bool, bool) clang/lib/Parse/ParseAST.cpp:163:7
    [...]

SUMMARY: AddressSanitizer: heap-buffer-overflow clang/lib/Serialization/ASTReader.cpp:10171:15 in clang::ASTReader::ReadString(llvm::SmallVectorImpl<unsigned long> const&, unsigned int&)
```

The reason is this particular RUN line:
```
// RUN: env CC_PRINT_HEADERS_FORMAT=json CC_PRINT_HEADERS_FILTERING=direct-per-file CC_PRINT_HEADERS_FILE=%t.txt %clang -fsyntax-only -I %S/Inputs/print-header-json -isystem %S/Inputs/print-header-json/system -fmodules -fimplicit-module-maps -fmodules-cache-path=%t %s -o /dev/null
```

which was added in 8df194f ("[Clang] Support includes translated to
module imports in -header-include-filtering=direct-per-file (llvm#156756)").

The problem is caused by an incremental build reusing stale cached
module files (.pcm) that are no longer binary-compatible with the
updated compiler. Adding a new sanitizer option altered the implicit
binary layout of the serialized LangOptions data structure. The build +
test system is oblivious to such changes. When the new compiler
attempted to read the old module file (from the previous test
invocation), it misinterpreted the data due to the layout mismatch,
resulting in a heap-buffer-overflow. Unfortunately Clang's PCM format
does not encode nor detect version mismatches here; a more graceful
failure mode would be preferable.

For now, fix the test to be more robust with incremental build + test.
MaskRay pushed a commit that referenced this pull request Oct 26, 2025
**Mitigation for:** google/sanitizers#749

**Disclosure:** I'm not an ASan compiler expert yet (I'm trying to
learn!), I primarily work in the runtime. Some of this PR was developed
with the help of AI tools (primarily as a "fuzzy `grep` engine"), but
I've manually refined and tested the output, and can speak for every
line. In general, I used it only to orient myself and for
"rubberducking".

**Context:**

The msvc ASan team (👋 ) has received an internal request to improve
clang's exception handling under ASan for Windows. Namely, we're
interested in **mitigating** this bug:
google/sanitizers#749

To summarize, today, clang + ASan produces a false-positive error for
this program:

```C++
#include <cstdio>
#include <exception>
int main()
{
	try	{
		throw std::exception("test");
	}catch (const std::exception& ex){
		puts(ex.what());
	}
	return 0;
}
```

The error reads as such:


```
C:\Users\dajusto\source\repros\upstream>type main.cpp
#include <cstdio>
#include <exception>
int main()
{
        try     {
                throw std::exception("test");
        }catch (const std::exception& ex){
                puts(ex.what());
        }
        return 0;
}
C:\Users\dajusto\source\repros\upstream>"C:\Users\dajusto\source\repos\llvm-project\build.runtimes\bin\clang.exe" -fsanitize=address -g -O0 main.cpp

C:\Users\dajusto\source\repros\upstream>a.exe
=================================================================
==19112==ERROR: AddressSanitizer: access-violation on unknown address 0x000000000000 (pc 0x7ff72c7c11d9 bp 0x0080000ff960 sp 0x0080000fcf50 T0)
==19112==The signal is caused by a READ memory access.
==19112==Hint: address points to the zero page.
    #0 0x7ff72c7c11d8 in main C:\Users\dajusto\source\repros\upstream\main.cpp:8
    #1 0x7ff72c7d479f in _CallSettingFrame C:\repos\msvc\src\vctools\crt\vcruntime\src\eh\amd64\handlers.asm:49
    #2 0x7ff72c7c8944 in __FrameHandler3::CxxCallCatchBlock(struct _EXCEPTION_RECORD *) C:\repos\msvc\src\vctools\crt\vcruntime\src\eh\frame.cpp:1567
    #3 0x7ffb4a90e3e5  (C:\WINDOWS\SYSTEM32\ntdll.dll+0x18012e3e5)
    #4 0x7ff72c7c1128 in main C:\Users\dajusto\source\repros\upstream\main.cpp:6
    #5 0x7ff72c7c33db in invoke_main C:\repos\msvc\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78
    llvm#6 0x7ff72c7c33db in __scrt_common_main_seh C:\repos\msvc\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288
    llvm#7 0x7ffb49b05c06  (C:\WINDOWS\System32\KERNEL32.DLL+0x180035c06)
    llvm#8 0x7ffb4a8455ef  (C:\WINDOWS\SYSTEM32\ntdll.dll+0x1800655ef)

==19112==Register values:
rax = 0  rbx = 80000ff8e0  rcx = 27d76d00000  rdx = 80000ff8e0
rdi = 80000fdd50  rsi = 80000ff6a0  rbp = 80000ff960  rsp = 80000fcf50
r8  = 100  r9  = 19930520  r10 = 8000503a90  r11 = 80000fd540
r12 = 80000fd020  r13 = 0  r14 = 80000fdeb8  r15 = 0
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: access-violation C:\Users\dajusto\source\repros\upstream\main.cpp:8 in main
==19112==ABORTING
```

The root of the issue _appears to be_ that ASan's instrumentation is
incompatible with Window's assumptions for instantiating `catch`-block's
parameters (`ex` in the snippet above).

The nitty gritty details are lost on me, but I understand that to make
this work without loss of ASan coverage, a "serious" refactoring is
needed. In the meantime, users risk false positive errors when pairing
ASan + catch-block parameters on Windows.

**To mitigate this** I think we should avoid instrumenting catch-block
parameters on Windows. It appears to me this is as "simple" as marking
catch block parameters as "uninteresting" in
`AddressSanitizer::isInterestingAlloca`. My manual tests seem to confirm
this.

I believe this is strictly better than today's status quo, where the
runtime generates false positives. Although we're now explicitly
choosing to instrument less, the benefit is that now more programs can
run with ASan without _funky_ macros that disable ASan on exception
blocks.

**This PR:** implements the mitigation above, and creates a simple new
test for it.

_Thanks!_

---------

Co-authored-by: Antonio Frighetto <me@antoniofrighetto.com>
MaskRay pushed a commit that referenced this pull request Nov 1, 2025
llvm#164955 has a use-after-scope
(https://lab.llvm.org/buildbot/#/builders/169/builds/16454):

```
==mlir-opt==3940651==ERROR: AddressSanitizer: stack-use-after-scope on address 0x6e1f6ba5c878 at pc 0x6336b214912a bp 0x7ffe607f1670 sp 0x7ffe607f1668
READ of size 4 at 0x6e1f6ba5c878 thread T0
    #0 0x6336b2149129 in size /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/ADT/SmallVector.h:80:32
    #1 0x6336b2149129 in operator[] /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/ADT/SmallVector.h:299:5
    #2 0x6336b2149129 in populateBoundsForShapedValueDim /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/mlir/lib/Dialect/MemRef/IR/ValueBoundsOpInterfaceImpl.cpp:113:43
...
```

This patch attempts to fix-forward by stack-allocating reassocIndices,
instead of taking a reference to a return value.
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