[MLIR][LLVMIR][OpenMP] Changes to scan Lowering from MLIR #1

anchuraj · 2025-04-18T20:47:46Z

Scan reductions are supported in OpenMP with the the help of scan directive. Reduction clause of the for loop/simd directive takes an inscan modifier if scan reduction is specified. With an inscan modifier, the body of the directive should specify a scan directive. This PR implements the lowering logic for scan reductions in workshare loops of OpenMP.
The body of the for loop is splitted into two loops and a scan reduction loop is added in the middle.

size num_iters = <num_iters>;
<type> buffer[num_iters];
for (i: 0..<num_iters>) {
  <input phase>;
  buffer[i] = red;
}
for (int k = 0; k != ceil(log2(num_iters)); ++k) {
  i=pow(2,k)
  for (size cnt = last_iter; cnt >= i; --cnt)
    buffer[cnt] op= buffer[cnt-i];
}
for (0..<num_iters>) {
  red = buffer[i] ;
  <scan phase>;
}

…gger memory is updated (llvm#129092)" This reverts commit daa4061. Original PR llvm#129092. I have restricted the test to X86 Windows because it turns out the only reason that `expr x.get()` would change m_memory_id is that on x86 we have to write the return address to the stack in ABIWindows_X86_64::PrepareTrivialCall: ``` // Save return address onto the stack if (!process_sp->WritePointerToMemory(sp, return_addr, error)) return false; ``` This is not required on AArch64 so m_memory_id was not changed: ``` (lldb) expr x.get() (int) $0 = 0 (lldb) process status -d Process 15316 stopped * thread #1, stop reason = Exception 0x80000003 encountered at address 0x7ff764a31034 frame #0: 0x00007ff764a31038 TestProcessModificationIdOnExpr.cpp.tmp`main at TestProcessModificationIdOnExpr.cpp:35 32 __builtin_debugtrap(); 33 __builtin_debugtrap(); 34 return 0; -> 35 } 36 37 // CHECK-LABEL: process status -d 38 // CHECK: m_stop_id: 2 ProcessModID: m_stop_id: 3 m_last_natural_stop_id: 0 m_resume_id: 0 m_memory_id: 0 ``` Really we should find a better way to force a memory write here, but I can't think of one right now.

we already check for `platform_sp` not null in one line below. existing code ``` if (platform_sp) { Status error; if (platform_sp) { ... ... } } ``` `platform_sp` null check is redundant and error variable is unused. ### TEST PLAN manual test ``` satyajanga@devvm21837:toolchain $ ./bin/lldb LLDB logging initialized. Logs stored in: /tmp (lldb) platform select host Platform: host Triple: x86_64-*-linux-gnu OS Version: 6.9.0 (6.9.0-0_fbk5_hardened_1_gf368ae920c1a) Hostname: 127.0.0.1 WorkingDir: /home/satyajanga/llvm-sand/build/Debug/fbcode-x86_64/toolchain Kernel: #1 SMP Tue Feb 11 07:24:41 PST 2025 Kernel: Linux Release: 6.9.0-0_fbk5_hardened_1_gf368ae920c1a Version: #1 SMP Tue Feb 11 07:24:41 PST 2025 (lldb) platform process list 144 matching processes were found on "host" PID PARENT USER TRIPLE NAME ====== ====== ========== ============================== ============================ 130461 874915 satyajanga x86_64-*-linux-gnu sushd 135505 874915 satyajanga x86_64-*-linux-gnu hg.real 817146 874915 satyajanga x86_64-*-linux-gnu vscode-thrift 874915 1 satyajanga 874947 874915 satyajanga ``` and running the existing tests ``` satyajanga@devvm21837:toolchain $ ./bin/llvm-lit -v ~/llvm-sand/external/llvm-project/lldb/test/API/commands/platform/ -- Testing: 9 tests, 9 workers -- PASS: lldb-api :: commands/platform/file/read/TestPlatformFileRead.py (1 of 9) PASS: lldb-api :: commands/platform/file/close/TestPlatformFileClose.py (2 of 9) UNSUPPORTED: lldb-api :: commands/platform/sdk/TestPlatformSDK.py (3 of 9) PASS: lldb-api :: commands/platform/basic/TestPlatformPython.py (4 of 9) PASS: lldb-api :: commands/platform/basic/TestPlatformCommand.py (5 of 9) PASS: lldb-api :: commands/platform/connect/TestPlatformConnect.py (6 of 9) PASS: lldb-api :: commands/platform/process/launch/TestPlatformProcessLaunch.py (7 of 9) PASS: lldb-api :: commands/platform/launchgdbserver/TestPlatformLaunchGDBServer.py (8 of 9) PASS: lldb-api :: commands/platform/process/list/TestProcessList.py (9 of 9) Testing Time: 13.48s Total Discovered Tests: 9 Unsupported: 1 (11.11%) Passed : 8 (88.89%) satyajanga@devvm21837:toolchain $ ```

llvm#138091) Check this error for more context (https://github.com/compiler-research/CppInterOp/actions/runs/14749797085/job/41407625681?pr=491#step:10:531) This fails with ``` * thread #1, name = 'CppInterOpTests', stop reason = signal SIGSEGV: address not mapped to object (fault address: 0x55500356d6d3) * frame #0: 0x00007fffee41cfe3 libclangCppInterOp.so.21.0gitclang::PragmaNamespace::~PragmaNamespace() + 99 frame #1: 0x00007fffee435666 libclangCppInterOp.so.21.0gitclang::Preprocessor::~Preprocessor() + 3830 frame #2: 0x00007fffee20917a libclangCppInterOp.so.21.0gitstd::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() + 58 frame llvm#3: 0x00007fffee224796 libclangCppInterOp.so.21.0gitclang::CompilerInstance::~CompilerInstance() + 838 frame llvm#4: 0x00007fffee22494d libclangCppInterOp.so.21.0gitclang::CompilerInstance::~CompilerInstance() + 13 frame llvm#5: 0x00007fffed95ec62 libclangCppInterOp.so.21.0gitclang::IncrementalCUDADeviceParser::~IncrementalCUDADeviceParser() + 98 frame llvm#6: 0x00007fffed9551b6 libclangCppInterOp.so.21.0gitclang::Interpreter::~Interpreter() + 102 frame llvm#7: 0x00007fffed95598d libclangCppInterOp.so.21.0gitclang::Interpreter::~Interpreter() + 13 frame llvm#8: 0x00007fffed9181e7 libclangCppInterOp.so.21.0gitcompat::createClangInterpreter(std::vector<char const*, std::allocator<char const*>>&) + 2919 ``` Problem : 1) The destructor currently handles no clearance for the DeviceParser and the DeviceAct. We currently only have this https://github.com/llvm/llvm-project/blob/976493822443c52a71ed3c67aaca9a555b20c55d/clang/lib/Interpreter/Interpreter.cpp#L416-L419 2) The ownership for DeviceCI currently is present in IncrementalCudaDeviceParser. But this should be similar to how the combination for hostCI, hostAction and hostParser are managed by the Interpreter. As on master the DeviceAct and DeviceParser are managed by the Interpreter but not DeviceCI. This is problematic because : IncrementalParser holds a Sema& which points into the DeviceCI. On master, DeviceCI is destroyed before the base class ~IncrementalParser() runs, causing Parser::reset() to access a dangling Sema (and as Sema holds a reference to Preprocessor which owns PragmaNamespace) we see this ``` * frame #0: 0x00007fffee41cfe3 libclangCppInterOp.so.21.0gitclang::PragmaNamespace::~PragmaNamespace() + 99 frame #1: 0x00007fffee435666 libclangCppInterOp.so.21.0gitclang::Preprocessor::~Preprocessor() + 3830 ```

When running the `openmp` testsuite on Solaris/amd64, many tests `FAIL` like ``` # | OMP: Error llvm#11: Stack overflow detected for OpenMP thread #1 ``` In a `Debug` build, I also get ``` # | Assertion failure at kmp_runtime.cpp(203): __kmp_gtid_get_specific() < 0 || __kmp_gtid_get_specific() == i. ``` Further investigation shows that just setting `__kmp_gtid_mode` to 3 massively reduces the number of failures. Tested on `amd64-pc-solaris2.11` and `x86_64-pc-linux-gnu`.

Fix for: `Assertion failed: (false && "Architecture or OS not supported"), function CreateRegisterContextForFrame, file /usr/src/contrib/llvm-project/lldb/source/Plugins/Process/elf-core/ThreadElfCore.cpp, line 182. PLEASE submit a bug report to https://bugs.freebsd.org/submit/ and include the crash backtrace. #0 0x000000080cd857c8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:723:13 #1 0x000000080cd85ed4 /usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:797:3 #2 0x000000080cd82ae8 llvm::sys::RunSignalHandlers() /usr/src/contrib/llvm-project/llvm/lib/Support/Signals.cpp:104:5 llvm#3 0x000000080cd861f0 SignalHandler /usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:403:3 llvm#4 0x000000080f159644 handle_signal /usr/src/lib/libthr/thread/thr_sig.c:298:3 `

These were failing on our Windows on Arm bot, or more precisely, not even completing. This is because Microsoft's C runtime does extra parameter validation. So when we called _read with an invalid fd, it called an invalid parameter handler instead of returning an error. https://learn.microsoft.com/en-us/%20cpp/c-runtime-library/reference/read?view=msvc-170 https://learn.microsoft.com/en-us/%20cpp/c-runtime-library/parameter-validation?view=msvc-170 (lldb) run Process 8440 launched: 'C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\tools\lldb\unittests\Host\HostTests.exe' (aarch64) Process 8440 stopped * thread #1, stop reason = Exception 0xc0000409 encountered at address 0x7ffb7453564c frame #0: 0x00007ffb7453564c ucrtbase.dll`_get_thread_local_invalid_parameter_handler + 652 ucrtbase.dll`_get_thread_local_invalid_parameter_handler: -> 0x7ffb7453564c <+652>: brk #0xf003 ucrtbase.dll`_invalid_parameter_noinfo: 0x7ffb74535650 <+0>: b 0x7ffb745354d8 ; _get_thread_local_invalid_parameter_handler + 280 0x7ffb74535654 <+4>: nop 0x7ffb74535658 <+8>: nop You can override this handler but I'm assuming that this reading after close isn't a crucial feature, so disabling the tests seems like the way to go. If it is crucial, we can check the fd before we use it. Tests added by llvm#143946.

# Benefit This patch fixes: 1. After `platform select ios-simulator`, `platform process list` will now print processes which are running in the iOS simulator. Previously, no process will be listed. 2. After `platform select ios-simulator`, `platform attach --name <name>` will succeed. Previously, it will error out saying no process is found. # Several bugs that is being fixed 1. During the process listing, add `aarch64` to the list of CPU types for which iOS simulators are checked for. 2. Given a candidate process, when checking for simulators, the original code will find the desired environment variable (`SIMULATOR_UDID`) and set the OS to iOS, but then the immediate next environment variable will set it back to macOS. 3. For processes running on simulator, set the triple's `Environment` to `Simulator`, so that such processes can pass the filtering [in this line](https://fburl.com/8nivnrjx). The original code leave it as the default `UnknownEnvironment`. # Manual test **With this patch:** ``` royshi-mac-home ~/public_llvm/build % bin/lldb (lldb) platform select ios-simulator (lldb) platform process list 240 matching processes were found on "ios-simulator" PID PARENT USER TRIPLE NAME ====== ====== ========== ============================== ============================ 40511 28844 royshi arm64-apple-ios-simulator FocusPlayground // my toy iOS app running on simulator ... // omit 28844 1 royshi arm64-apple-ios-simulator launchd_sim (lldb) process attach --name FocusPlayground Process 40511 stopped * thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP frame #0: 0x0000000104e3cb70 libsystem_kernel.dylib`mach_msg2_trap + 8 libsystem_kernel.dylib`mach_msg2_trap: -> 0x104e3cb70 <+8>: ret ... // omit ``` **Without this patch:** ``` $ bin/lldb (lldb) platform select ios-simulator (lldb) platform process list error: no processes were found on the "ios-simulator" platform (lldb) process attach --name FocusPlayground error: attach failed: could not find a process named FocusPlayground ``` # Unittest See PR.

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 llvm#3 (/lib/x86_64-linux-gnu/libc.so.6+0x3fdf0) llvm#4 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12772:0 llvm#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. ```

…erver (llvm#148774) Summary: There was a deadlock was introduced by [PR llvm#146441](llvm#146441) which changed `CurrentThreadIsPrivateStateThread()` to `CurrentThreadPosesAsPrivateStateThread()`. This change caused the execution path in [`ExecutionContextRef::SetTargetPtr()`](https://github.com/llvm/llvm-project/blob/10b5558b61baab59c7d3dff37ffdf0861c0cc67a/lldb/source/Target/ExecutionContext.cpp#L513) to now enter a code block that was previously skipped, triggering [`GetSelectedFrame()`](https://github.com/llvm/llvm-project/blob/10b5558b61baab59c7d3dff37ffdf0861c0cc67a/lldb/source/Target/ExecutionContext.cpp#L522) which leads to a deadlock. Thread 1 gets m_modules_mutex in [`ModuleList::AppendImpl`](https://github.com/llvm/llvm-project/blob/96148f92146e5211685246722664e51ec730e7ba/lldb/source/Core/ModuleList.cpp#L218), Thread 3 gets m_language_runtimes_mutex in [`GetLanguageRuntime`](https://github.com/llvm/llvm-project/blob/96148f92146e5211685246722664e51ec730e7ba/lldb/source/Target/Process.cpp#L1501), but then Thread 1 waits for m_language_runtimes_mutex in [`GetLanguageRuntime`](https://github.com/llvm/llvm-project/blob/96148f92146e5211685246722664e51ec730e7ba/lldb/source/Target/Process.cpp#L1501) while Thread 3 waits for m_modules_mutex in [`ScanForGNUstepObjCLibraryCandidate`](https://github.com/llvm/llvm-project/blob/96148f92146e5211685246722664e51ec730e7ba/lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp#L57). This fixes the deadlock by adding a scoped block around the mutex lock before the call to the notifier, and moved the notifier call outside of the mutex-guarded section. The notifier call [`NotifyModuleAdded`](https://github.com/llvm/llvm-project/blob/96148f92146e5211685246722664e51ec730e7ba/lldb/source/Target/Target.cpp#L1810) should be thread-safe, since the module should be added to the `ModuleList` before the mutex is released, and the notifier doesn't modify the module list further, and the call is operates on local state and the `Target` instance. ### Deadlocked Thread backtraces: ``` * thread llvm#3, name = 'dbg.evt-handler', stop reason = signal SIGSTOP * frame #0: 0x00007f2f1e2973dc libc.so.6`futex_wait(private=0, expected=2, futex_word=0x0000563786bd5f40) at futex-internal.h:146:13 /*... a bunch of mutex related bt ... */ liblldb.so.21.0git`std::lock_guard<std::recursive_mutex>::lock_guard(this=0x00007f2f0f1927b0, __m=0x0000563786bd5f40) at std_mutex.h:229:19 frame llvm#8: 0x00007f2f27946eb7 liblldb.so.21.0git`ScanForGNUstepObjCLibraryCandidate(modules=0x0000563786bd5f28, TT=0x0000563786bd5eb8) at GNUstepObjCRuntime.cpp:60:41 frame llvm#9: 0x00007f2f27946c80 liblldb.so.21.0git`lldb_private::GNUstepObjCRuntime::CreateInstance(process=0x0000563785e1d360, language=eLanguageTypeObjC) at GNUstepObjCRuntime.cpp:87:8 frame llvm#10: 0x00007f2f2746fca5 liblldb.so.21.0git`lldb_private::LanguageRuntime::FindPlugin(process=0x0000563785e1d360, language=eLanguageTypeObjC) at LanguageRuntime.cpp:210:36 frame llvm#11: 0x00007f2f2742c9e3 liblldb.so.21.0git`lldb_private::Process::GetLanguageRuntime(this=0x0000563785e1d360, language=eLanguageTypeObjC) at Process.cpp:1516:9 ... frame llvm#21: 0x00007f2f2750b5cc liblldb.so.21.0git`lldb_private::Thread::GetSelectedFrame(this=0x0000563785e064d0, select_most_relevant=DoNoSelectMostRelevantFrame) at Thread.cpp:274:48 frame llvm#22: 0x00007f2f273f9957 liblldb.so.21.0git`lldb_private::ExecutionContextRef::SetTargetPtr(this=0x00007f2f0f193778, target=0x0000563786bd5be0, adopt_selected=true) at ExecutionContext.cpp:525:32 frame llvm#23: 0x00007f2f273f9714 liblldb.so.21.0git`lldb_private::ExecutionContextRef::ExecutionContextRef(this=0x00007f2f0f193778, target=0x0000563786bd5be0, adopt_selected=true) at ExecutionContext.cpp:413:3 frame llvm#24: 0x00007f2f270e80af liblldb.so.21.0git`lldb_private::Debugger::GetSelectedExecutionContext(this=0x0000563785d83bc0) at Debugger.cpp:1225:23 frame llvm#25: 0x00007f2f271bb7fd liblldb.so.21.0git`lldb_private::Statusline::Redraw(this=0x0000563785d83f30, update=true) at Statusline.cpp:136:41 ... * thread #1, name = 'lldb', stop reason = signal SIGSTOP * frame #0: 0x00007f2f1e2973dc libc.so.6`futex_wait(private=0, expected=2, futex_word=0x0000563785e1dd98) at futex-internal.h:146:13 /*... a bunch of mutex related bt ... */ liblldb.so.21.0git`std::lock_guard<std::recursive_mutex>::lock_guard(this=0x00007ffe62be0488, __m=0x0000563785e1dd98) at std_mutex.h:229:19 frame llvm#8: 0x00007f2f2742c8d1 liblldb.so.21.0git`lldb_private::Process::GetLanguageRuntime(this=0x0000563785e1d360, language=eLanguageTypeC_plus_plus) at Process.cpp:1510:41 frame llvm#9: 0x00007f2f2743c46f liblldb.so.21.0git`lldb_private::Process::ModulesDidLoad(this=0x0000563785e1d360, module_list=0x00007ffe62be06a0) at Process.cpp:6082:36 ... frame llvm#13: 0x00007f2f2715cf03 liblldb.so.21.0git`lldb_private::ModuleList::AppendImpl(this=0x0000563786bd5f28, module_sp=ptr = 0x563785cec560, use_notifier=true) at ModuleList.cpp:246:19 frame llvm#14: 0x00007f2f2715cf4c liblldb.so.21.0git`lldb_private::ModuleList::Append(this=0x0000563786bd5f28, module_sp=ptr = 0x563785cec560, notify=true) at ModuleList.cpp:251:3 ... frame llvm#19: 0x00007f2f274349b3 liblldb.so.21.0git`lldb_private::Process::ConnectRemote(this=0x0000563785e1d360, remote_url=(Data = "connect://localhost:1234", Length = 24)) at Process.cpp:3250:9 frame llvm#20: 0x00007f2f27411e0e liblldb.so.21.0git`lldb_private::Platform::DoConnectProcess(this=0x0000563785c59990, connect_url=(Data = "connect://localhost:1234", Length = 24), plugin_name=(Data = "gdb-remote", Length = 10), debugger=0x0000563785d83bc0, stream=0x00007ffe62be3128, target=0x0000563786bd5be0, error=0x00007ffe62be1ca0) at Platform.cpp:1926:23 ``` ## Test Plan: Built a hello world a.out Run server in one terminal: ``` ~/llvm/build/Debug/bin/lldb-server g :1234 a.out ``` Run client in another terminal ``` ~/llvm/build/Debug/bin/lldb -o "gdb-remote 1234" -o "b hello.cc:3" ``` Before: Client hangs indefinitely ``` ~/llvm/build/Debug/bin/lldb -o "gdb-remote 1234" -o "b main" (lldb) gdb-remote 1234 ^C^C ``` After: ``` ~/llvm/build/Debug/bin/lldb -o "gdb-remote 1234" -o "b hello.cc:3" (lldb) gdb-remote 1234 Process 837068 stopped * thread #1, name = 'a.out', stop reason = signal SIGSTOP frame #0: 0x00007ffff7fe4a60 ld-linux-x86-64.so.2`_start: -> 0x7ffff7fe4a60 <+0>: movq %rsp, %rdi 0x7ffff7fe4a63 <+3>: callq 0x7ffff7fe5780 ; _dl_start at rtld.c:522:1 ld-linux-x86-64.so.2`_dl_start_user: 0x7ffff7fe4a68 <+0>: movq %rax, %r12 0x7ffff7fe4a6b <+3>: movl 0x18067(%rip), %eax ; _dl_skip_args (lldb) b hello.cc:3 Breakpoint 1: where = a.out`main + 15 at hello.cc:4:13, address = 0x00005555555551bf (lldb) c Process 837068 resuming Process 837068 stopped * thread #1, name = 'a.out', stop reason = breakpoint 1.1 frame #0: 0x00005555555551bf a.out`main at hello.cc:4:13 1 #include <iostream> 2 3 int main() { -> 4 std::cout << "Hello World" << std::endl; 5 return 0; 6 } ```

…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 ... ```

M68k's SETCC instruction (`scc`) distinctly fills the destination byte with all 1s. If boolean contents are set to `ZeroOrOneBooleanContent`, LLVM can mistakenly think the destination holds `0x01` instead of `0xff` and emit broken code as a result. This change corrects the boolean content type to `ZeroOrNegativeOneBooleanContent`. For example, this IR: ```llvm define dso_local signext range(i8 0, 2) i8 @testBool(i32 noundef %a) local_unnamed_addr #0 { entry: %cmp = icmp eq i32 %a, 4660 %. = zext i1 %cmp to i8 ret i8 %. } ``` would previously build as: ```asm testBool: ; @testBool cmpi.l llvm#4660, (4,%sp) seq %d0 and.l llvm#255, %d0 rts ``` Notice the `zext` is erroneously not clearing the low bits, and thus the register returns with 255 instead of 1. This patch fixes the issue: ```asm testBool: ; @testBool cmpi.l llvm#4660, (4,%sp) seq %d0 and.l #1, %d0 rts ``` Most of the tests containing `scc` suffered from the same value error as described above, so those tests have been updated to match the new output (which also logically corrects them).

## 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) llvm#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 llvm#4 0x00007f9c04ea7707 lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Status*) (usr/bin/../lib/liblldb.so.15+0x22a7707) llvm#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)

…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 llvm#3 0x0000565131b18c30 llvm::sys::RunSignalHandlers() /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/llvm/lib/Support/Signals.cpp:105:18 llvm#4 0x0000565131b18c30 SignalHandler(int, siginfo_t*, void*) /local-ssd/sayans/Softwares/llvm-repo/llvm-project-latest/llvm/lib/Support/Unix/Signals.inc:409:3 llvm#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.

…build breakage from llvm#155943) (llvm#156103) ASan now detects dereferences of zero-sized allocations (llvm#155943; the corresponding MSan change is llvm#155944). This appears to have detected a bug in CrossOverTest.cpp, causing a buildbot breakage. This patch fixes the test. Buildbot report: https://lab.llvm.org/buildbot/#/builders/4/builds/8732 ``` 7: ==949882==ERROR: AddressSanitizer: heap-buffer-overflow on address 0xf169cfbe0010 at pc 0xb5f45efc6d1c bp 0xffffd933e460 sp 0xffffd933e458 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 8: READ of size 1 at 0xf169cfbe0010 thread T0 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 9: #0 0xb5f45efc6d18 in LLVMFuzzerTestOneInput /home/tcwg-buildbot/worker/clang-aarch64-sve-vls-2stage/llvm/compiler-rt/test/fuzzer/CrossOverTest.cpp:48:7 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ check:20'1 ? possible intended match 10: #1 0xb5f45eec7288 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /home/tcwg-buildbot/worker/clang-aarch64-sve-vls-2stage/llvm/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:619:13 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11: #2 0xb5f45eec85d4 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) /home/tcwg-buildbot/worker/clang-aarch64-sve-vls-2stage/llvm/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:812:3 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 12: llvm#3 0xb5f45eec8c60 in fuzzer::Fuzzer::Loop(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) /home/tcwg-buildbot/worker/clang-aarch64-sve-vls-2stage/llvm/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:872:3 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 13: llvm#4 0xb5f45eeb5c64 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /home/tcwg-buildbot/worker/clang-aarch64-sve-vls-2stage/llvm/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:923:6 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 14: llvm#5 0xb5f45eee09d0 in main /home/tcwg-buildbot/worker/clang-aarch64-sve-vls-2stage/llvm/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10 check:20'0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ``` For context, FuzzerLoop.cpp:812 tries empty input: ``` 810 // Test the callback with empty input and never try it again. 811 uint8_t dummy = 0; 812 ExecuteCallback(&dummy, 0); ```

IR Builder Changes to Support Scan Operation

6d59b7e

anchuraj force-pushed the scanMlirSupport branch from c4790ab to 35e9e71 Compare April 18, 2025 20:57

[MLIR][LLVMIR][OpenMP] Changes to scan reduction Lowering from MLIR

48e3f10

anchuraj force-pushed the scanMlirSupport branch from 35e9e71 to 48e3f10 Compare April 18, 2025 21:57

anchuraj force-pushed the scan-IRBuilder-Support branch from 6d59b7e to 0ad35dc Compare May 1, 2025 21:41

anchuraj force-pushed the scan-IRBuilder-Support branch 2 times, most recently from 4b50e9c to 323d3e3 Compare June 13, 2025 20:19

anchuraj force-pushed the scan-IRBuilder-Support branch 4 times, most recently from 5343c53 to a8fb6bd Compare July 27, 2025 23:44

anchuraj force-pushed the scan-IRBuilder-Support branch from 0c970b0 to 91b069a Compare August 7, 2025 19:16

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[MLIR][LLVMIR][OpenMP] Changes to scan Lowering from MLIR #1

[MLIR][LLVMIR][OpenMP] Changes to scan Lowering from MLIR #1

Uh oh!

anchuraj commented Apr 18, 2025 •

edited

Loading

Uh oh!

Uh oh!

[MLIR][LLVMIR][OpenMP] Changes to scan Lowering from MLIR #1

Are you sure you want to change the base?

[MLIR][LLVMIR][OpenMP] Changes to scan Lowering from MLIR #1

Uh oh!

Conversation

anchuraj commented Apr 18, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Uh oh!

anchuraj commented Apr 18, 2025 •

edited

Loading