[libc][test] make DeathTestExecutors and FPExceptionHelpers hermetic

[nickdesaulniers]

Towards the goal of being able to cross compile full builds, I hit a snag yesterday when cross compiling some of the unit tests. With some other smaller fixes to our cmake, I can cross compile (and run in QEMU) some unit tests, but quite a few still fail to build.

80cf21d added a TODO that implies that the LibcDeathTestExecutors and LibcFPExceptionHelpers are indeed not yet hermetic. (It then unsets LLVM_LIBC_FULL_BUILD which changes the set compiler options from _get_common_test_compile_options).

Here's an example failure:

llvm-project/libc/test/UnitTest/LibcDeathTestExecutors.cpp:15:10: fatal error: 'assert.h' file not found
   15 | #include <assert.h>
      |          ^~~~~~~~~~

I suspect we can start relying on hdr/ for these from the UnitTests.

So that needs to get fixed first, before we can cross compile the entire unit test suite.

cc @lntue

---

FWIW, my cmake invocation is:

$ cmake ../runtimes -GNinja -DLLVM_ENABLE_LLD=ON -DCMAKE_BUILD_TYPE=Debug -DLLVM_ENABLE_RUNTIMES="libc" -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DLLVM_LIBC_FULL_BUILD=ON -DLIBC_TARGET_TRIPLE=aarch64-linux-gnu -DCMAKE_CROSSCOMPILING_EMULATOR=qemu-aarch64 -DLIBC_KERNEL_HEADERS=/tmp/sysroot/include

and my kernel headers were built via:

$ make LLVM=1 ARCH=arm64 INSTALL_HDR_PATH=/tmp/sysroot headers_install

[llvmbot]

@llvm/issue-subscribers-libc

Author: Nick Desaulniers (nickdesaulniers)

Towards the goal of being able to cross compile full builds, I hit a snag yesterday when cross compiling some of the unit tests. With some other smaller fixes to our cmake, I can cross compile (and run in QEMU) _some_ unit tests, but quite a few still fail to build.

80cf21d added a TODO that implies that the LibcDeathTestExecutors and LibcFPExceptionHelpers are indeed not yet hermetic. (It then unsets LLVM_LIBC_FULL_BUILD which changes the set compiler options from _get_common_test_compile_options).

Here's an example failure:

llvm-project/libc/test/UnitTest/LibcDeathTestExecutors.cpp:15:10: fatal error: 'assert.h' file not found
   15 | #include <assert.h>
      |          ^~~~~~~~~~

I suspect we can start relying on hdr/ for these from the UnitTests.

So that needs to get fixed first, before we can cross compile the entire unit test suite.

cc @lntue

---

FWIW, my cmake invocation is:

$ cmake ../runtimes -GNinja -DLLVM_ENABLE_LLD=ON -DCMAKE_BUILD_TYPE=Debug -DLLVM_ENABLE_RUNTIMES="libc" -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DLLVM_LIBC_FULL_BUILD=ON -DLIBC_TARGET_TRIPLE=aarch64-linux-gnu -DCMAKE_CROSSCOMPILING_EMULATOR=qemu-aarch64 -DLIBC_KERNEL_HEADERS=/tmp/sysroot/include

and my kernel headers were built via:

$ make LLVM=1 ARCH=arm64 INSTALL_HDR_PATH=/tmp/sysroot headers_install

[nickdesaulniers]

If we make a proxy hdr/ for assert, we could probably also use it from libc/src/__support/libc_assert.h.