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jdoerfert and others added 23 commits June 13, 2024 01:34
Through the new `-foffload-via-llvm` flag, CUDA kernels can now be
lowered to the LLVM/Offload API. On the Clang side, this is simply done
by using the OpenMP offload toolchain and emitting calls to `llvm*`
functions to orchestrate the kernel launch rather than `cuda*`
functions. These `llvm*` functions are implemented on top of the
existing LLVM/Offload API.

As we are about to redefine the Offload API, this wil help us in the
design process as a second offload language.

We do not support any CUDA APIs yet, however, we could:
  https://www.osti.gov/servlets/purl/1892137

For proper host execution we need to resurrect/rebase
  https://tianshilei.me/wp-content/uploads/2021/12/llpp-2021.pdf
(which was designed for debugging).

```
❯❯❯ cat test.cu
extern "C" {
void *llvm_omp_target_alloc_shared(size_t Size, int DeviceNum);
void llvm_omp_target_free_shared(void *DevicePtr, int DeviceNum);
}

__global__ void square(int *A) { *A = 42; }

int main(int argc, char **argv) {
  int DevNo = 0;
  int *Ptr = reinterpret_cast<int *>(llvm_omp_target_alloc_shared(4, DevNo));
  *Ptr = 7;
  printf("Ptr %p, *Ptr %i\n", Ptr, *Ptr);
  square<<<1, 1>>>(Ptr);
  printf("Ptr %p, *Ptr %i\n", Ptr, *Ptr);
  llvm_omp_target_free_shared(Ptr, DevNo);
}

❯❯❯ clang++ test.cu -O3 -o test123 -foffload-via-llvm --offload-arch=native

❯❯❯ llvm-objdump --offloading test123

test123:        file format elf64-x86-64

OFFLOADING IMAGE [0]:
kind            elf
arch            gfx90a
triple          amdgcn-amd-amdhsa
producer        openmp

❯❯❯ LIBOMPTARGET_INFO=16 ./test123
Ptr 0x155448ac8000, *Ptr 7
Ptr 0x155448ac8000, *Ptr 42
```
This provides the header overlay for cuda_runtime.h which is found
before any CUDA installation (none is necessary). Some basic APIs are
defined in terms of the omp_target_* ones, but with the API redesign
the requirements of CUDA should be taken into account.

Based on: llvm#94549
The offload APIs, and the CUDA wrappers in clang, now support "default
streams" per thread (and per device). It should be per context but we
don't really expose that concept yet. The KernelArguments allow an
LLVM/Offload user to provide a "AsyncInfoQueue", which is plugin
dependent and can later also be created outside or queried from the
runtime. User managed "queues" are kept persistent, thus not returned to
the pool once synchronized.

The CUDA tests will synchronize via `cudaDeviceSynchronize` before
checking the results.

Based on: llvm#94821
shiltian pushed a commit that referenced this pull request Jul 24, 2024
…linux (llvm#99613)

Examples of the output:

ARM:
```
# ./a.out 
AddressSanitizer:DEADLYSIGNAL
=================================================================
==122==ERROR: AddressSanitizer: SEGV on unknown address 0x0000007a (pc 0x76e13ac0 bp 0x7eb7fd00 sp 0x7eb7fcc8 T0)
==122==The signal is caused by a READ memory access.
==122==Hint: address points to the zero page.
    #0 0x76e13ac0  (/lib/libc.so.6+0x7cac0)
    #1 0x76dce680 in gsignal (/lib/libc.so.6+0x37680)
    #2 0x005c2250  (/root/a.out+0x145250)
    #3 0x76db982c  (/lib/libc.so.6+0x2282c)
    #4 0x76db9918 in __libc_start_main (/lib/libc.so.6+0x22918)

==122==Register values:
 r0 = 0x00000000   r1 = 0x0000007a   r2 = 0x0000000b   r3 = 0x76d95020  
 r4 = 0x0000007a   r5 = 0x00000001   r6 = 0x005dcc5c   r7 = 0x0000010c  
 r8 = 0x0000000b   r9 = 0x76f9ece0  r10 = 0x00000000  r11 = 0x7eb7fd00  
r12 = 0x76dce670   sp = 0x7eb7fcc8   lr = 0x76e13ab4   pc = 0x76e13ac0  
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/libc.so.6+0x7cac0) 
==122==ABORTING
```

AArch64:
```
# ./a.out 
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==99==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000063 (pc 0x007fbbbc5860 bp 0x007fcfdcb700 sp 0x007fcfdcb700 T99)
==99==The signal is caused by a UNKNOWN memory access.
==99==Hint: address points to the zero page.
    #0 0x007fbbbc5860  (/lib64/libc.so.6+0x82860)
    #1 0x007fbbb81578  (/lib64/libc.so.6+0x3e578)
    #2 0x00556051152c  (/root/a.out+0x3152c)
    #3 0x007fbbb6e268  (/lib64/libc.so.6+0x2b268)
    #4 0x007fbbb6e344  (/lib64/libc.so.6+0x2b344)
    #5 0x0055604e45ec  (/root/a.out+0x45ec)

==99==Register values:
 x0 = 0x0000000000000000   x1 = 0x0000000000000063   x2 = 0x000000000000000b   x3 = 0x0000007fbbb41440  
 x4 = 0x0000007fbbb41580   x5 = 0x3669288942d44cce   x6 = 0x0000000000000000   x7 = 0x00000055605110b0  
 x8 = 0x0000000000000083   x9 = 0x0000000000000000  x10 = 0x0000000000000000  x11 = 0x0000000000000000  
x12 = 0x0000007fbbdb3360  x13 = 0x0000000000010000  x14 = 0x0000000000000039  x15 = 0x00000000004113a0  
x16 = 0x0000007fbbb81560  x17 = 0x0000005560540138  x18 = 0x000000006474e552  x19 = 0x0000000000000063  
x20 = 0x0000000000000001  x21 = 0x000000000000000b  x22 = 0x0000005560511510  x23 = 0x0000007fcfdcb918  
x24 = 0x0000007fbbdb1b50  x25 = 0x0000000000000000  x26 = 0x0000007fbbdb2000  x27 = 0x000000556053f858  
x28 = 0x0000000000000000   fp = 0x0000007fcfdcb700   lr = 0x0000007fbbbc584c   sp = 0x0000007fcfdcb700  
UndefinedBehaviorSanitizer can not provide additional info.
SUMMARY: UndefinedBehaviorSanitizer: SEGV (/lib64/libc.so.6+0x82860) 
==99==ABORTING
```
shiltian pushed a commit that referenced this pull request Jul 24, 2024
Somewhat confusingly a `SCEVMulExpr` is a `SCEVNAryExpr`, so can have
> 2 operands. Previously, the vscale immediate matching did not check
the number of operands of the `SCEVMulExpr`, so would ignore any
operands after the first two.

This led to incorrect codegen (and results) for ArmSME in IREE
(https://github.com/iree-org/iree), which sometimes addresses things
that are a `vscale * vscale` multiple away. The test added with this
change shows an example reduced from IREE. The second write should
be offset from the first `16 * vscale * vscale` (* 4 bytes), however,
previously LSR dropped the second vscale and instead offset the write by
`#4, mul vl`, which is an offset of `16 * vscale` (* 4 bytes).
@jdoerfert jdoerfert force-pushed the gpu_san branch 3 times, most recently from 3a99d18 to acf4219 Compare August 15, 2024 00:29
jdoerfert pushed a commit that referenced this pull request Aug 30, 2024
…104523)

Compilers and language runtimes often use helper functions that are
fundamentally uninteresting when debugging anything but the
compiler/runtime itself. This patch introduces a user-extensible
mechanism that allows for these frames to be hidden from backtraces and
automatically skipped over when navigating the stack with `up` and
`down`.

This does not affect the numbering of frames, so `f <N>` will still
provide access to the hidden frames. The `bt` output will also print a
hint that frames have been hidden.

My primary motivation for this feature is to hide thunks in the Swift
programming language, but I'm including an example recognizer for
`std::function::operator()` that I wished for myself many times while
debugging LLDB.

rdar://126629381


Example output. (Yes, my proof-of-concept recognizer could hide even
more frames if we had a method that returned the function name without
the return type or I used something that isn't based off regex, but it's
really only meant as an example).

before:
```
(lldb) thread backtrace --filtered=false
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame #3: 0x0000000100003968 a.out`std::__1::__function::__alloc_func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()[abi:se200000](this=0x000000016fdff280, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:171:12
    frame #4: 0x00000001000026bc a.out`std::__1::__function::__func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()(this=0x000000016fdff278, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:313:10
    frame #5: 0x0000000100003c38 a.out`std::__1::__function::__value_func<int (int, int)>::operator()[abi:se200000](this=0x000000016fdff278, __args=0x000000016fdff224, __args=0x000000016fdff220) const at function.h:430:12
    frame #6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame #8: 0x0000000183cdf154 dyld`start + 2476
(lldb) 
```

after

```
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame #6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame #8: 0x0000000183cdf154 dyld`start + 2476
Note: Some frames were hidden by frame recognizers
```
jdoerfert pushed a commit that referenced this pull request Aug 30, 2024
`JITDylibSearchOrderResolver` local variable can be destroyed before
completion of all callbacks. Capture it together with `Deps` in
`OnEmitted` callback.

Original error:

```
==2035==ERROR: AddressSanitizer: stack-use-after-return on address 0x7bebfa155b70 at pc 0x7ff2a9a88b4a bp 0x7bec08d51980 sp 0x7bec08d51978
READ of size 8 at 0x7bebfa155b70 thread T87 (tf_xla-cpu-llvm)
    #0 0x7ff2a9a88b49 in operator() llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:55:58
    #1 0x7ff2a9a88b49 in __invoke<(lambda at llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:55:9) &, const llvm::DenseMap<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> >, llvm::DenseMapInfo<llvm::orc::JITDylib *, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> > > > &> libcxx/include/__type_traits/invoke.h:149:25
    #2 0x7ff2a9a88b49 in __call<(lambda at llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:55:9) &, const llvm::DenseMap<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> >, llvm::DenseMapInfo<llvm::orc::JITDylib *, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> > > > &> libcxx/include/__type_traits/invoke.h:224:5
    #3 0x7ff2a9a88b49 in operator() libcxx/include/__functional/function.h:210:12
    #4 0x7ff2a9a88b49 in void std::__u::__function::__policy_invoker<void (llvm::DenseMap<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr,
```
jdoerfert pushed a commit that referenced this pull request Sep 5, 2024
Static destructor can race with calls to notify and trigger tsan
warning.

```
WARNING: ThreadSanitizer: data race (pid=5787)
  Write of size 1 at 0x55bec9df8de8 by thread T23:
    #0 pthread_mutex_destroy [third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:1344](third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp?l=1344&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x1b12affb) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #1 __libcpp_recursive_mutex_destroy [third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h:91](third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h?l=91&cl=669089572):10 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d4e9) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #2 std::__tsan::recursive_mutex::~recursive_mutex() [third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp:52](third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp?l=52&cl=669089572):11 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d4e9)
    #3 ~SmartMutex [third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h:28](third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h?l=28&cl=669089572):11 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaedfe) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #4 (anonymous namespace)::PerfJITEventListener::~PerfJITEventListener() [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp:65](third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp?l=65&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaedfe)
    #5 cxa_at_exit_callback_installed_at(void*) [third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:437](third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp?l=437&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x1b172cb9) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #6 llvm::JITEventListener::createPerfJITEventListener() [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp:496](third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp?l=496&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcad8f5) (BuildId: ff25ace8b17d9863348bb1759c47246c)
```
```
Previous atomic read of size 1 at 0x55bec9df8de8 by thread T192 (mutexes: write M0, write M1):
    #0 pthread_mutex_unlock [third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:1387](third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp?l=1387&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x1b12b6bb) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #1 __libcpp_recursive_mutex_unlock [third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h:87](third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h?l=87&cl=669089572):10 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d589) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #2 std::__tsan::recursive_mutex::unlock() [third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp:64](third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp?l=64&cl=669089572):11 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d589)
    #3 unlock [third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h:47](third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h?l=47&cl=669089572):16 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaf968) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #4 ~lock_guard [third_party/crosstool/v18/stable/src/libcxx/include/__mutex/lock_guard.h:39](third_party/crosstool/v18/stable/src/libcxx/include/__mutex/lock_guard.h?l=39&cl=669089572):101 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaf968)
    #5 (anonymous namespace)::PerfJITEventListener::notifyObjectLoaded(unsigned long, llvm::object::ObjectFile const&, llvm::RuntimeDyld::LoadedObjectInfo const&) [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp:290](https://cs.corp.google.com/piper///depot/google3/third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp?l=290&cl=669089572):1 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaf968)
    #6 llvm::orc::RTDyldObjectLinkingLayer::onObjEmit(llvm::orc::MaterializationResponsibility&, llvm::object::OwningBinary<llvm::object::ObjectFile>, std::__tsan::unique_ptr<llvm::RuntimeDyld::MemoryManager, std::__tsan::default_delete<llvm::RuntimeDyld::MemoryManager>>, std::__tsan::unique_ptr<llvm::RuntimeDyld::LoadedObjectInfo, std::__tsan::default_delete<llvm::RuntimeDyld::LoadedObjectInfo>>, std::__tsan::unique_ptr<llvm::DenseMap<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>, llvm::DenseMapInfo<llvm::orc::JITDylib*, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>>>, std::__tsan::default_delete<llvm::DenseMap<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>, llvm::DenseMapInfo<llvm::orc::JITDylib*, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>>>>>, llvm::Error) [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:386](https://cs.corp.google.com/piper///depot/google3/third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp?l=386&cl=669089572):10 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bc404a8) (BuildId: ff25ace8b17d9863348bb1759c47246c)
```
jdoerfert pushed a commit that referenced this pull request Sep 20, 2024
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`.
jdoerfert pushed a commit that referenced this pull request Oct 2, 2024
…ext is not fully initialized (llvm#110481)

As this comment around target initialization implies:
```
  // This can be NULL if we don't know anything about the architecture or if
  // the target for an architecture isn't enabled in the llvm/clang that we
  // built
```

There are cases where we might fail to call `InitBuiltinTypes` when
creating the backing `ASTContext` for a `TypeSystemClang`. If that
happens, the builtins `QualType`s, e.g., `VoidPtrTy`/`IntTy`/etc., are
not initialized and dereferencing them as we do in
`GetBuiltinTypeForEncodingAndBitSize` (and other places) will lead to
nullptr-dereferences. Example backtrace:
```
(lldb) run
Assertion failed: (!isNull() && "Cannot retrieve a NULL type pointer"), function getCommonPtr, file Type.h, line 958.
Process 2680 stopped
* thread #15, name = '<lldb.process.internal-state(pid=2712)>', stop reason = hit program assert
    frame #4: 0x000000010cdf3cdc liblldb.20.0.0git.dylib`DWARFASTParserClang::ExtractIntFromFormValue(lldb_private::CompilerType const&, lldb_private::plugin::dwarf::DWARFFormValue const&) const (.cold.1) + 
liblldb.20.0.0git.dylib`DWARFASTParserClang::ParseObjCMethod(lldb_private::ObjCLanguage::MethodName const&, lldb_private::plugin::dwarf::DWARFDIE const&, lldb_private::CompilerType, ParsedDWARFTypeAttributes
, bool) (.cold.1):
->  0x10cdf3cdc <+0>:  stp    x29, x30, [sp, #-0x10]!
    0x10cdf3ce0 <+4>:  mov    x29, sp
    0x10cdf3ce4 <+8>:  adrp   x0, 545
    0x10cdf3ce8 <+12>: add    x0, x0, #0xa25 ; "ParseObjCMethod"
Target 0: (lldb) stopped.
(lldb) bt
* thread #15, name = '<lldb.process.internal-state(pid=2712)>', stop reason = hit program assert
    frame #0: 0x0000000180d08600 libsystem_kernel.dylib`__pthread_kill + 8
    frame #1: 0x0000000180d40f50 libsystem_pthread.dylib`pthread_kill + 288
    frame #2: 0x0000000180c4d908 libsystem_c.dylib`abort + 128
    frame #3: 0x0000000180c4cc1c libsystem_c.dylib`__assert_rtn + 284
  * frame #4: 0x000000010cdf3cdc liblldb.20.0.0git.dylib`DWARFASTParserClang::ExtractIntFromFormValue(lldb_private::CompilerType const&, lldb_private::plugin::dwarf::DWARFFormValue const&) const (.cold.1) + 
    frame #5: 0x0000000109d30acc liblldb.20.0.0git.dylib`lldb_private::TypeSystemClang::GetBuiltinTypeForEncodingAndBitSize(lldb::Encoding, unsigned long) + 1188
    frame #6: 0x0000000109aaaed4 liblldb.20.0.0git.dylib`DynamicLoaderMacOS::NotifyBreakpointHit(void*, lldb_private::StoppointCallbackContext*, unsigned long long, unsigned long long) + 384
```

This patch adds a one-time user-visible warning for when we fail to
initialize the AST to indicate that initialization went wrong for the
given target. Additionally, we add checks for whether one of the
`ASTContext` `QualType`s is invalid before dereferencing any builtin
types.

The warning would look as follows:
```
(lldb) target create "a.out"
Current executable set to 'a.out' (arm64).
(lldb) b main
warning: Failed to initialize builtin ASTContext types for target 'some-unknown-triple'. Printing variables may behave unexpectedly.
Breakpoint 1: where = a.out`main + 8 at stepping.cpp:5:14, address = 0x0000000100003f90
```

rdar://134869779
jdoerfert pushed a commit that referenced this pull request May 9, 2025
The mcmodel=tiny memory model is only valid on ARM targets. While trying
this on X86 compiler throws an internal error along with stack dump.
llvm#125641
This patch resolves the issue.
Reduced test case:
```
#include <stdio.h>
int main( void )
{
printf( "Hello, World!\n" ); 
return 0; 
}
```
```
0.	Program arguments: /opt/compiler-explorer/clang-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -mcmodel=tiny <source>
1.	<eof> parser at end of file
 #0 0x0000000003b10218 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b10218)
 #1 0x0000000003b0e35c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b0e35c)
 #2 0x0000000003a5dbc3 llvm::CrashRecoveryContext::HandleExit(int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a5dbc3)
 #3 0x0000000003b05cfe llvm::sys::Process::Exit(int, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b05cfe)
 #4 0x0000000000d4e3eb LLVMErrorHandler(void*, char const*, bool) cc1_main.cpp:0:0
 #5 0x0000000003a67c93 llvm::report_fatal_error(llvm::Twine const&, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a67c93)
 #6 0x0000000003a67df8 (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a67df8)
 #7 0x0000000002549148 llvm::X86TargetMachine::X86TargetMachine(llvm::Target const&, llvm::Triple const&, llvm::StringRef, llvm::StringRef, llvm::TargetOptions const&, std::optional<llvm::Reloc::Model>, std::optional<llvm::CodeModel::Model>, llvm::CodeGenOptLevel, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x2549148)
 #8 0x00000000025491fc llvm::RegisterTargetMachine<llvm::X86TargetMachine>::Allocator(llvm::Target const&, llvm::Triple const&, llvm::StringRef, llvm::StringRef, llvm::TargetOptions const&, std::optional<llvm::Reloc::Model>, std::optional<llvm::CodeModel::Model>, llvm::CodeGenOptLevel, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x25491fc)
 #9 0x0000000003db74cc clang::emitBackendOutput(clang::CompilerInstance&, clang::CodeGenOptions&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3db74cc)
#10 0x0000000004460d95 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4460d95)
#11 0x00000000060005ec clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x60005ec)
#12 0x00000000044614b5 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x44614b5)
#13 0x0000000004737121 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4737121)
#14 0x00000000046b777b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x46b777b)
#15 0x00000000048229e3 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x48229e3)
#16 0x0000000000d50621 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd50621)
#17 0x0000000000d48e2d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#18 0x00000000044acc99 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#19 0x0000000003a5dac3 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a5dac3)
#20 0x00000000044aceb9 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
llvm#21 0x00000000044710dd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x44710dd)
llvm#22 0x0000000004472071 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4472071)
llvm#23 0x000000000447c3fc clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x447c3fc)
llvm#24 0x0000000000d4d2b1 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd4d2b1)
llvm#25 0x0000000000c12464 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xc12464)
llvm#26 0x00007ae43b029d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
llvm#27 0x00007ae43b029e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
llvm#28 0x0000000000d488c5 _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd488c5)
```

---------

Co-authored-by: Shashwathi N <[email protected]>
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