[DRAFT] Loop exploration function pass #7

cjappl · 2024-09-04T20:22:59Z

Attempt to detect unbound loops in our function pass

cjappl · 2024-09-04T20:23:27Z

clang/lib/CodeGen/BackendUtil.cpp

            FPM.addPass(RealtimeSanitizerPass(Opts));
          });
+    }


Here is where we add the SROA pass

cjappl · 2024-09-04T20:23:46Z

llvm/include/llvm/Transforms/Scalar/SROA.h

@@ -36,6 +36,8 @@ class SROAPass : public PassInfoMixin<SROAPass> {

  void printPipeline(raw_ostream &OS,
                     function_ref<StringRef(StringRef)> MapClassName2PassName);
+
+  static bool isRequired() { return true; }


SROA does not ever run, unless I add this hack here

…lvm#107294) Random testing revealed it's possible to crash the analyzer with the command line invocation: clang -cc1 -analyze -analyzer-checker=nullability empty.c where the source file, empty.c is an empty source file. ``` clang: <root>/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp:56: void clang::ento::CheckerManager::finishedCheckerRegistration(): Assertion `Event.second.HasDispatcher && "No dispatcher registered for an event"' failed. PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ Stack dump: 0. Program arguments: clang -cc1 -analyze -analyzer-checker=nullability nullability-nocrash.c #0 ... ... #7 <addr> clang::ento::CheckerManager::finishedCheckerRegistration() #8 <addr> clang::ento::CheckerManager::CheckerManager(clang::ASTContext&, clang::AnalyzerOptions&, clang::Preprocessor const&, llvm::ArrayRef<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>, llvm::ArrayRef<std::function<void (clang::ento::CheckerRegistry&)>>) ``` This commit removes the assertion which failed here, because it was logically incorrect: it required that if an Event is handled by some (enabled) checker, then there must be an **enabled** checker which can emit that kind of Event. It should be OK to disable the event-producing checkers but enable an event-consuming checker which has different responsibilities in addition to handling the events. Note that this assertion was in an `#ifndef NDEBUG` block, so this change does not impact the non-debug builds. Co-authored-by: Vince Bridgers <[email protected]>

When SPARC Asan testing is enabled by PR llvm#107405, many Linux/sparc64 tests just hang like ``` #0 0xf7ae8e90 in syscall () from /usr/lib32/libc.so.6 #1 0x701065e8 in __sanitizer::FutexWait(__sanitizer::atomic_uint32_t*, unsigned int) () at compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp:766 #2 0x70107c90 in Wait () at compiler-rt/lib/sanitizer_common/sanitizer_mutex.cpp:35 #3 0x700f7cac in Lock () at compiler-rt/lib/asan/../sanitizer_common/sanitizer_mutex.h:196 #4 Lock () at compiler-rt/lib/asan/../sanitizer_common/sanitizer_thread_registry.h:98 #5 LockThreads () at compiler-rt/lib/asan/asan_thread.cpp:489 #6 0x700e9c8c in __asan::BeforeFork() () at compiler-rt/lib/asan/asan_posix.cpp:157 #7 0xf7ac83f4 in ?? () from /usr/lib32/libc.so.6 Backtrace stopped: previous frame identical to this frame (corrupt stack?) ``` It turns out that this happens in tests using `internal_fork` (e.g. invoking `llvm-symbolizer`): unlike most other Linux targets, which use `clone`, Linux/sparc64 has to use `__fork` instead. While `clone` doesn't trigger `pthread_atfork` handlers, `__fork` obviously does, causing the hang. To avoid this, this patch disables `InstallAtForkHandler` and lets the ASan tests run to completion. Tested on `sparc64-unknown-linux-gnu`.

… depobj construct (llvm#114221) A codegen crash is occurring when a depend object was initialized with omp_all_memory in the depobj directive. llvm#114214 The root cause of issue looks to be the improper handling of the dependency list when omp_all_memory was specified. The change introduces the use of OMPTaskDataTy to manage dependencies. The buildDependences function is called to construct the dependency list, and the list is iterated over to emit and store the dependencies. Reduced Test Case : ``` #include <omp.h> int main() { omp_depend_t obj; #pragma omp depobj(obj) depend(inout: omp_all_memory) } ``` ``` #1 0x0000000003de6623 SignalHandler(int) Signals.cpp:0:0 #2 0x00007f8e4a6b990f (/lib64/libpthread.so.0+0x1690f) #3 0x00007f8e4a117d2a raise (/lib64/libc.so.6+0x4ad2a) #4 0x00007f8e4a1193e4 abort (/lib64/libc.so.6+0x4c3e4) #5 0x00007f8e4a10fc69 __assert_fail_base (/lib64/libc.so.6+0x42c69) #6 0x00007f8e4a10fcf1 __assert_fail (/lib64/libc.so.6+0x42cf1) #7 0x0000000004114367 clang::CodeGen::CodeGenFunction::EmitOMPDepobjDirective(clang::OMPDepobjDirective const&) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x4114367) #8 0x00000000040f8fac clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x40f8fac) #9 0x00000000040ff4fb clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x40ff4fb) #10 0x00000000041847b2 clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x41847b2) #11 0x0000000004199e4a clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x4199e4a) #12 0x00000000041f7b9d clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x41f7b9d) #13 0x00000000041f16a3 clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x41f16a3) #14 0x00000000041fd954 clang::CodeGen::CodeGenModule::EmitDeferred() (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x41fd954) realtime-sanitizer#15 0x0000000004200277 clang::CodeGen::CodeGenModule::Release() (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x4200277) realtime-sanitizer#16 0x00000000046b6a49 (anonymous namespace)::CodeGeneratorImpl::HandleTranslationUnit(clang::ASTContext&) ModuleBuilder.cpp:0:0 realtime-sanitizer#17 0x00000000046b4cb6 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x46b4cb6) realtime-sanitizer#18 0x0000000006204d5c clang::ParseAST(clang::Sema&, bool, bool) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x6204d5c) realtime-sanitizer#19 0x000000000496b278 clang::FrontendAction::Execute() (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x496b278) realtime-sanitizer#20 0x00000000048dd074 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x48dd074) realtime-sanitizer#21 0x0000000004a38092 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0x4a38092) realtime-sanitizer#22 0x0000000000fd4e9c cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0xfd4e9c) realtime-sanitizer#23 0x0000000000fcca73 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0 realtime-sanitizer#24 0x0000000000fd140c clang_main(int, char**, llvm::ToolContext const&) (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0xfd140c) realtime-sanitizer#25 0x0000000000ee2ef3 main (/opt/cray/pe/cce/18.0.1/cce-clang/x86_64/bin/clang-18+0xee2ef3) realtime-sanitizer#26 0x00007f8e4a10224c __libc_start_main (/lib64/libc.so.6+0x3524c) realtime-sanitizer#27 0x0000000000fcaae9 _start /home/abuild/rpmbuild/BUILD/glibc-2.31/csu/../sysdeps/x86_64/start.S:120:0 clang: error: unable to execute command: Aborted ``` --------- Co-authored-by: Chandra Ghale <[email protected]>

…onger cause a crash (llvm#116569) This PR fixes a bug introduced by llvm#110199, which causes any half float argument to crash the compiler on MIPS64. Currently compiling this bit of code with `llc -mtriple=mips64`: ``` define void @half_args(half %a) nounwind { entry: ret void } ``` Crashes with the following log: ``` LLVM ERROR: unable to allocate function argument #0 PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace. Stack dump: 0. Program arguments: llc -mtriple=mips64 1. Running pass 'Function Pass Manager' on module '<stdin>'. 2. Running pass 'MIPS DAG->DAG Pattern Instruction Selection' on function '@half_args' #0 0x000055a3a4013df8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x32d0df8) #1 0x000055a3a401199e llvm::sys::RunSignalHandlers() (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x32ce99e) #2 0x000055a3a40144a8 SignalHandler(int) Signals.cpp:0:0 #3 0x00007f00bde558c0 __restore_rt libc_sigaction.c:0:0 #4 0x00007f00bdea462c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76 #5 0x00007f00bde55822 gsignal ./signal/../sysdeps/posix/raise.c:27:6 #6 0x00007f00bde3e4af abort ./stdlib/abort.c:81:7 #7 0x000055a3a3f80e3c llvm::report_fatal_error(llvm::Twine const&, bool) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x323de3c) #8 0x000055a3a2e20dfa (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x20dddfa) #9 0x000055a3a2a34e20 llvm::MipsTargetLowering::LowerFormalArguments(llvm::SDValue, unsigned int, bool, llvm::SmallVectorImpl<llvm::ISD::InputArg> const&, llvm::SDLoc const&, llvm::SelectionDAG&, llvm::SmallVectorImpl<llvm::SDValue>&) const MipsISelLowering.cpp:0:0 #10 0x000055a3a3d896a9 llvm::SelectionDAGISel::LowerArguments(llvm::Function const&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x30466a9) #11 0x000055a3a3e0b3ec llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x30c83ec) #12 0x000055a3a3e09e21 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x30c6e21) #13 0x000055a3a2aae1ca llvm::MipsDAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) MipsISelDAGToDAG.cpp:0:0 #14 0x000055a3a3e07706 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x30c4706) realtime-sanitizer#15 0x000055a3a3051ed6 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x230eed6) realtime-sanitizer#16 0x000055a3a35a3ec9 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x2860ec9) realtime-sanitizer#17 0x000055a3a35ac3b2 llvm::FPPassManager::runOnModule(llvm::Module&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x28693b2) realtime-sanitizer#18 0x000055a3a35a499c llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x286199c) realtime-sanitizer#19 0x000055a3a262abbb main (/home/davide/Ps2/rps2-tools/prefix/bin/llc+0x18e7bbb) realtime-sanitizer#20 0x00007f00bde3fc4c __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3 realtime-sanitizer#21 0x00007f00bde3fd05 call_init ./csu/../csu/libc-start.c:128:20 realtime-sanitizer#22 0x00007f00bde3fd05 __libc_start_main@GLIBC_2.2.5 ./csu/../csu/libc-start.c:347:5 realtime-sanitizer#23 0x000055a3a2624921 _start /builddir/glibc-2.39/csu/../sysdeps/x86_64/start.S:117:0 ``` This is caused by the fact that after the change, `f16`s are no longer lowered as `f32`s in calls. Two possible fixes are available: - Update calling conventions to properly support passing `f16` as integers. - Update `useFPRegsForHalfType()` to return `true` so that `f16` are still kept in `f32` registers, as before llvm#110199. This PR implements the first solution to not introduce any more ABI changes as llvm#110199 already did. As of what is the correct ABI for halfs, I don't think there is a correct answer. GCC doesn't support halfs on MIPS, and I couldn't find any information on old MIPS ABI manuals either.

…abort (llvm#117603) Hey guys, I found that Flang's built-in ABORT function is incomplete when I was using it. Compared with gfortran's ABORT (which can both abort and print out a backtrace), flang's ABORT implementation lacks the function of printing out a backtrace. This feature is essential for debugging and understanding the call stack at the failure point. To solve this problem, I completed the "// TODO:" of the abort function, and then implemented an additional built-in function BACKTRACE for flang. After a brief reading of the relevant source code, I used backtrace and backtrace_symbols in "execinfo.h" to quickly implement this. But since I used the above two functions directly, my implementation is slightly different from gfortran's implementation (in the output, the function call stack before main is additionally output, and the function line number is missing). In addition, since I used the above two functions, I did not need to add -g to embed debug information into the ELF file, but needed -rdynamic to ensure that the symbols are added to the dynamic symbol table (so that the function name will be printed out). Here is a comparison of the output between gfortran 's backtrace and my implementation: gfortran's implemention output: ``` #0 0x557eb71f4184 in testfun2_ at /home/hunter/plct/fortran/test.f90:5 #1 0x557eb71f4165 in testfun1_ at /home/hunter/plct/fortran/test.f90:13 #2 0x557eb71f4192 in test_backtrace at /home/hunter/plct/fortran/test.f90:17 #3 0x557eb71f41ce in main at /home/hunter/plct/fortran/test.f90:18 ``` my impelmention output: ``` Backtrace: #0 ./test(_FortranABacktrace+0x32) [0x574f07efcf92] #1 ./test(testfun2_+0x14) [0x574f07efc7b4] #2 ./test(testfun1_+0xd) [0x574f07efc7cd] #3 ./test(_QQmain+0x9) [0x574f07efc7e9] #4 ./test(main+0x12) [0x574f07efc802] #5 /usr/lib/libc.so.6(+0x25e08) [0x76954694fe08] #6 /usr/lib/libc.so.6(__libc_start_main+0x8c) [0x76954694fecc] #7 ./test(_start+0x25) [0x574f07efc6c5] ``` test program is: ``` function testfun2() result(err) implicit none integer :: err err = 1 call backtrace end function testfun2 subroutine testfun1() implicit none integer :: err integer :: testfun2 err = testfun2() end subroutine testfun1 program test_backtrace call testfun1() end program test_backtrace ``` I am well aware of the importance of line numbers, so I am now working on implementing line numbers (by parsing DWARF information) and supporting cross-platform (Windows) support.

## 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 #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) #7 0x0000562fb2a8395d clang::driver::Driver::BuildCompilation(llvm::ArrayRef<char const*>) (llvm-project/build/bin/clang+++0x41ef95d) #8 0x0000562faf92684c clang_main(int, char**, llvm::ToolContext const&) (llvm-project/build/bin/clang+++0x109284c) #9 0x0000562faf826cc6 main (llvm-project/build/bin/clang+++0xf92cc6) #10 0x00007fcbf6699083 __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:342:3 #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 ```

cjappl commented Sep 4, 2024

View reviewed changes

clang/lib/CodeGen/BackendUtil.cpp

FPM.addPass(RealtimeSanitizerPass(Opts));

});

}

Copy link

Owner Author

cjappl Sep 4, 2024

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Here is where we add the SROA pass

cjappl commented Sep 4, 2024

View reviewed changes

cjappl force-pushed the loop_exploration_function_pass branch from e4d2102 to b0c405c Compare September 6, 2024 18:55

cjappl added 7 commits September 9, 2024 14:11

First version

15821d0

WIP: Loop pass

0a02dcd

Cleanup

5f4d0b0

Fix incorrect conditional predicting loop count

b86f26a

Fix clang format

2e8aef7

working with hack

b31279d

Fix clang format

428d2ec

cjappl force-pushed the loop_exploration_function_pass branch from b0c405c to 428d2ec Compare September 9, 2024 21:21

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[DRAFT] Loop exploration function pass #7

[DRAFT] Loop exploration function pass #7

Uh oh!

cjappl commented Sep 4, 2024

Uh oh!

cjappl Sep 4, 2024

Uh oh!

cjappl Sep 4, 2024

Uh oh!

Uh oh!

[DRAFT] Loop exploration function pass #7

Are you sure you want to change the base?

[DRAFT] Loop exploration function pass #7

Uh oh!

Conversation

cjappl commented Sep 4, 2024

Uh oh!

cjappl Sep 4, 2024

Choose a reason for hiding this comment

Uh oh!

cjappl Sep 4, 2024

Choose a reason for hiding this comment

Uh oh!

Uh oh!