ispc
Failure building 1.17.0 and 1.18.0 with XE_ENABLED
On ArchLinux, using the following components:
clang/llvm/openmp 13.0.1
spirv-llvm-translator 13.0.0@c9f1e369
level-zero 1.7.9
vc-intrinsics 0.1.0
Building command:
cmake -B build -S ispc-1.17.0 \
-DCMAKE_INSTALL_PREFIX=/usr \
-DISPC_INCLUDE_EXAMPLES=OFF \
-DISPC_NO_DUMPS=ON \
-DXE_ENABLED=ON \
-DXE_DEPS_DIR=/usr
make -C build
The main (ispc) compilation itself goes fine, but during ispc_xpu_examples we get this:
make[5]: Entering directory '/build/ispc/src/build/xpu_examples/src/ispc_xpu_examples-build'
[ 50%] Building ISPC object /build/ispc/src/build/xpu_examples/src/ispc_xpu_examples-build/aobench/local_ispc/aobench.dev.o
/build/ispc/src/ispc-1.17.0/src/main.cpp(396): FATAL ERROR: Unhandled signal sent to process; terminating.
***
*** Please file a bug report at https://github.com/ispc/ispc/issues
*** (Including as much information as you can about how to reproduce this error).
*** You have apparently encountered a bug in the compiler that we'd like to fix!
***
make[5]: *** [aobench/CMakeFiles/xe_aobench.dir/build.make:75: aobench/local_ispc/aobench.dev.o] Aborted (core dumped)
make[5]: Leaving directory '/build/ispc/src/build/xpu_examples/src/ispc_xpu_examples-build'
make[4]: *** [CMakeFiles/Makefile2:387: aobench/CMakeFiles/xe_aobench.dir/all] Error 2
The issue is a bit different now with 1.18.0, it has a more specific output:
/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/12.1.0/../../../../include/c++/12.1.0/bits/stl_vector.h:1123: std::vector::reference std::vector<llvm::Constant *>::operator[](std::vector::size_type) [_Tp = llvm::Constant *, _Alloc = std::allocator<llvm::Constant *>]: Assertion '__n < this->size()' failed.
/build/ispc/src/ispc-1.18.0/src/main.cpp(404): FATAL ERROR: Unhandled signal sent to process; terminating.
***
*** Please file a bug report at https://github.com/ispc/ispc/issues
*** (Including as much information as you can about how to reproduce this error).
*** You have apparently encountered a bug in the compiler that we'd like to fix!
***
This looks like https://github.com/ispc/ispc/issues/2192, but not sure how it was solved (@ndowens)?
OK, thanks from the solution of #2192, I’ve narrowed it down to -Wp,-D_GLIBCXX_ASSERTIONS in our CXXFLAGS. Per upstream documentation, this
enables extra error checking in the form of precondition assertions, such as bounds checking in strings and null pointer checks when dereferencing smart pointers.
So this likely reveals some bounds/memory issue.
It is not related to XE_ENABLED builds. Seems that it was a bug in ISPC code for ages which can be only discoverable by using -D_GLIBCXX_ASSERTIONS. Proposed fix https://github.com/ispc/ispc/pull/2353.
