[clang] [lldb] clang: Do not overwrite a module's DataLayout in the backend (PR #224012)

[David Spickett via cfe-commits]

DavidSpickett wrote:

We have some test-suite failures on Arm 32-bit: https://lab.llvm.org/buildbot/#/builders/122/builds/4
```
fatal error: error in backend: Can't create a MachineFunction using a Module with a Target-incompatible DataLayout attached
  Target DataLayout: e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64
  Module DataLayout: e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64

PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and dumped files.
Stack dump:
0.  Program arguments: /buildbot/clang-armv8-lld-2stage/stage2.install/bin/clang++ -DNDEBUG -x c++ -mcpu=neoverse-n1 -fuse-ld=lld -w -Werror=date-time -xir -MD -MT Bitcode/simd_ops/CMakeFiles/simd_ops.dir/ARM_halide_runtime.bc.o -MF CMakeFiles/simd_ops.dir/ARM_halide_runtime.bc.o.d -o CMakeFiles/simd_ops.dir/ARM_halide_runtime.bc.o -c /buildbot/clang-armv8-lld-2stage/test/test-suite/Bitcode/simd_ops/ARM_halide_runtime.bc
1.  Code generation
2.  Running pass 'Function Pass Manager' on module '/buildbot/clang-armv8-lld-2stage/test/test-suite/Bitcode/simd_ops/ARM_halide_runtime.bc'.
3.  Running pass 'ARM Instruction Selection' on function '@_ZN6Halide7Runtime8Internal14default_mallocEPvj'
```
I'll see if that can be reproduced with just clang shortly, I expect so.

https://github.com/llvm/llvm-project/pull/224012