[clang] Fix packed being ignored on ms_struct bitfields (PR #182792)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-x86_64-linux-bootstrap-msan` running on `sanitizer-buildbot5` while building `clang` at step 2 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/164/builds/19592

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

```
Step 2 (annotate) failure: 'python ../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py' (failure)
...
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/ld.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/main.py:74: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 97227 tests, 64 workers --
Testing:  0.. 10
FAIL: Clang :: Layout/ms-x86-bitfields-overflow.c (15028 of 97227)
******************** TEST 'Clang :: Layout/ms-x86-bitfields-overflow.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/clang -cc1 -internal-isystem /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/lib/clang/23/include -nostdsysteminc -triple x86_64-unknown-linux-gnu -fms-extensions -fdump-record-layouts -fsyntax-only /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c 2>/dev/null             | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# executed command: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/clang -cc1 -internal-isystem /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/lib/clang/23/include -nostdsysteminc -triple x86_64-unknown-linux-gnu -fms-extensions -fdump-record-layouts -fsyntax-only /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# note: command had no output on stdout or stderr
# executed command: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# .---command stderr------------
# | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c:23:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: | [sizeof=32, align=32]
# |                ^
# | <stdin>:5:25: note: scanning from here
# |  0:2-3 | _BitInt(250) f2
# |                         ^
# | <stdin>:6:2: note: possible intended match here
# |  | [sizeof=32, align=1]
# |  ^
# | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c:28:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: | [sizeof=64, align=64]
# |                ^
# | <stdin>:11:27: note: scanning from here
# |  0:2-256 | _BitInt(500) f2
# |                           ^
# | <stdin>:12:2: note: possible intended match here
# |  | [sizeof=64, align=1]
# |  ^
# | 
# | Input file: <stdin>
# | Check file: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            1:  
Step 11 (stage2/msan check) failure: stage2/msan check (failure)
...
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/ld.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/main.py:74: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 97227 tests, 64 workers --
Testing:  0.. 10
FAIL: Clang :: Layout/ms-x86-bitfields-overflow.c (15028 of 97227)
******************** TEST 'Clang :: Layout/ms-x86-bitfields-overflow.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/clang -cc1 -internal-isystem /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/lib/clang/23/include -nostdsysteminc -triple x86_64-unknown-linux-gnu -fms-extensions -fdump-record-layouts -fsyntax-only /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c 2>/dev/null             | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# executed command: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/clang -cc1 -internal-isystem /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/lib/clang/23/include -nostdsysteminc -triple x86_64-unknown-linux-gnu -fms-extensions -fdump-record-layouts -fsyntax-only /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# note: command had no output on stdout or stderr
# executed command: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# .---command stderr------------
# | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c:23:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: | [sizeof=32, align=32]
# |                ^
# | <stdin>:5:25: note: scanning from here
# |  0:2-3 | _BitInt(250) f2
# |                         ^
# | <stdin>:6:2: note: possible intended match here
# |  | [sizeof=32, align=1]
# |  ^
# | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c:28:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: | [sizeof=64, align=64]
# |                ^
# | <stdin>:11:27: note: scanning from here
# |  0:2-256 | _BitInt(500) f2
# |                           ^
# | <stdin>:12:2: note: possible intended match here
# |  | [sizeof=64, align=1]
# |  ^
# | 
# | Input file: <stdin>
# | Check file: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            1:  
Step 14 (stage3/msan check) failure: stage3/msan check (failure)
...
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/ld.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/llvm/utils/lit/lit/main.py:74: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 93522 tests, 64 workers --
Testing:  0.. 10.
FAIL: Clang :: Layout/ms-x86-bitfields-overflow.c (15031 of 93522)
******************** TEST 'Clang :: Layout/ms-x86-bitfields-overflow.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/clang -cc1 -internal-isystem /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/lib/clang/23/include -nostdsysteminc -triple x86_64-unknown-linux-gnu -fms-extensions -fdump-record-layouts -fsyntax-only /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c 2>/dev/null             | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# executed command: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/clang -cc1 -internal-isystem /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/lib/clang/23/include -nostdsysteminc -triple x86_64-unknown-linux-gnu -fms-extensions -fdump-record-layouts -fsyntax-only /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# note: command had no output on stdout or stderr
# executed command: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm_build2_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# .---command stderr------------
# | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c:23:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: | [sizeof=32, align=32]
# |                ^
# | <stdin>:5:25: note: scanning from here
# |  0:2-3 | _BitInt(250) f2
# |                         ^
# | <stdin>:6:2: note: possible intended match here
# |  | [sizeof=32, align=1]
# |  ^
# | /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c:28:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: | [sizeof=64, align=64]
# |                ^
# | <stdin>:11:27: note: scanning from here
# |  0:2-256 | _BitInt(500) f2
# |                           ^
# | <stdin>:12:2: note: possible intended match here
# |  | [sizeof=64, align=1]
# |  ^
# | 
# | Input file: <stdin>
# | Check file: /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/test/Layout/ms-x86-bitfields-overflow.c
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            1:  

```

</details>

https://github.com/llvm/llvm-project/pull/182792