SPARC lacks support for over-aligned dynamic alloca

[rorth]

The SPARC backend lacks support for over-aligned dynamic alloca. So far, I've encountered the issue in the testsuite (D133493:

FAILED: MultiSource/UnitTests/C++11/frame_layout/CMakeFiles/frame_layout.dir/frame_layout.cpp.o
[...]
fatal error: error in backend: Function "_Z10test_frameILj4096ELb1ELj2048ELb0ELb0EJEEvDpT4_jPKcP13trace_elementd": over-aligned dynamic alloca not supported.
void test_frame<4096u, true, 2048u, false, false>(, unsigned int, char const*, trace_element*, double)

Additionally, it breaks asan support with several instances of the same issue:

      4 fatal error: error in backend: Function "_Z21MemSetOOBTestTemplateIcEvj": over-aligned dynamic alloca not supported.
      3 fatal error: error in backend: Function "_Z21StrLenOOBTestTemplatePcjN12_GLOBAL__N_17OOBKindE": over-aligned dynamic alloca not supported.
      4 fatal error: error in backend: Function "_Z24asan_write_sized_alignedPhj": over-aligned dynamic alloca not supported.
      4 fatal error: error in backend: Function "_ZN48AddressSanitizerInternalInterface_SetShadow_Test8TestBodyEv": over-aligned dynamic alloca not supported.
      4 fatal error: error in backend: Function "_ZN52AddressSanitizer_HasFeatureAddressSanitizerTest_Test8TestBodyEv": over-aligned dynamic alloca not supported.
      4 fatal error: error in backend: Function "_ZN56AddressSanitizerInterface_GetEstimatedAllocatedSize_Test8TestBodyEv": over-aligned dynamic alloca not supported.
      4 fatal error: error in backend: Function "_ZN7testing8internal16BoolFromGTestEnvEPKcb": over-aligned dynamic alloca not supported.
      3 fatal error: error in backend: Function "main": over-aligned dynamic alloca not supported.

which caused be to disable asan completely.

This puts clang at a considerable advantage to gcc which handles both just fine.

[rorth]

/cherry-pick 83de0f31e66f1d1a9706b8e057475efd3ea1ed3a

[llvmbot]

Failed to cherry-pick: 83de0f31e66f1d1a9706b8e057475efd3ea1ed3a

https://github.com/llvm/llvm-project/actions/runs/3016468488

Please manually backport the fix and push it to your github fork. Once this is done, please add a comment like this:

/branch <user>/<repo>/<branch>

[rorth]

The commit hash is for the llvm-test-suite repo, not llvm-project. How would I request a backport there? I don't believe a fork is necessary here.

[tru]

You can just manually cherry-pick it over to the release/15.x branch for the test-suite.

[rorth]

... which would have required approval first ;-) Alternatively, I've now created a fork before seeing your message:

/branch rorth/llvm-test-suite/issue57626