[llvm] [llvm-debuginfo-analyzer] Fix crash with WebAssembly dead code (PR #141616)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `fuchsia-x86_64-linux` running on `fuchsia-debian-64-us-central1-a-1` while building `llvm` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/11/builds/18127

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/fuchsia-linux.py ...' (failure)
...
  Passed           : 46217 (97.76%)
  Expectedly Failed:    27 (0.06%)
[1377/1379] Linking CXX executable unittests/Transforms/Scalar/ScalarTests
[1378/1379] Running the LLVM regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/wasm-ld
-- Testing: 59866 tests, 60 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80..
FAIL: LLVM :: tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s (53081 of 59866)
******************** TEST 'LLVM :: tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/llvm-mc -arch=wasm32 -filetype=obj                /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s                 -o /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test/tools/llvm-debuginfo-analyzer/WebAssembly/Output/wasm-32bit-tombstone.s.tmp.wasm-32bit-tombstone.wasm # RUN: at line 27
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/llvm-mc -arch=wasm32 -filetype=obj /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s -o /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test/tools/llvm-debuginfo-analyzer/WebAssembly/Output/wasm-32bit-tombstone.s.tmp.wasm-32bit-tombstone.wasm
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/llvm-mc: error: invalid target 'wasm32'.
--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 
********************
Failed Tests (1):
  LLVM :: tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s


Testing Time: 80.58s

Total Discovered Tests: 66137
  Skipped          :    35 (0.05%)
  Unsupported      : 18463 (27.92%)
  Passed           : 47566 (71.92%)
  Expectedly Failed:    72 (0.11%)
  Failed           :     1 (0.00%)
FAILED: test/CMakeFiles/check-llvm /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test/CMakeFiles/check-llvm 
cd /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test && /usr/bin/python3.10 /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/./bin/llvm-lit -sv /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test
ninja: build stopped: subcommand failed.
['ninja', '-C', '/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx', 'check-llvm', 'check-clang', 'check-lld'] exited with return code 1.
@@@STEP_FAILURE@@@
Step 7 (check) failure: check (failure)
...
  Passed           : 46217 (97.76%)
  Expectedly Failed:    27 (0.06%)
[1377/1379] Linking CXX executable unittests/Transforms/Scalar/ScalarTests
[1378/1379] Running the LLVM regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/wasm-ld
-- Testing: 59866 tests, 60 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80..
FAIL: LLVM :: tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s (53081 of 59866)
******************** TEST 'LLVM :: tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/llvm-mc -arch=wasm32 -filetype=obj                /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s                 -o /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test/tools/llvm-debuginfo-analyzer/WebAssembly/Output/wasm-32bit-tombstone.s.tmp.wasm-32bit-tombstone.wasm # RUN: at line 27
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/llvm-mc -arch=wasm32 -filetype=obj /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/test/tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s -o /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test/tools/llvm-debuginfo-analyzer/WebAssembly/Output/wasm-32bit-tombstone.s.tmp.wasm-32bit-tombstone.wasm
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/bin/llvm-mc: error: invalid target 'wasm32'.
--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 
********************
Failed Tests (1):
  LLVM :: tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s


Testing Time: 80.58s

Total Discovered Tests: 66137
  Skipped          :    35 (0.05%)
  Unsupported      : 18463 (27.92%)
  Passed           : 47566 (71.92%)
  Expectedly Failed:    72 (0.11%)
  Failed           :     1 (0.00%)
FAILED: test/CMakeFiles/check-llvm /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test/CMakeFiles/check-llvm 
cd /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test && /usr/bin/python3.10 /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/./bin/llvm-lit -sv /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx/test
ninja: build stopped: subcommand failed.
['ninja', '-C', '/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-2rcnnkbx', 'check-llvm', 'check-clang', 'check-lld'] exited with return code 1.
program finished with exit code 0
elapsedTime=1234.874067

```

</details>

https://github.com/llvm/llvm-project/pull/141616