[clang] [clang] Avoid sandbox violation in Windows signal handler (PR #190615)

Mon Apr 6 08:32:46 PDT 2026

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 53500 tests passed
* 1069 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.SemaCXX/windows_sandbox_violtion.cpp</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\clang.exe -std=c++17 -fsyntax-only C:\_work\llvm-project\llvm-project\clang\test\SemaCXX\windows_sandbox_violtion.cpp
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -std=c++17 -fsyntax-only 'C:\_work\llvm-project\llvm-project\clang\test\SemaCXX\windows_sandbox_violtion.cpp'
# .---command stderr------------
# | Assertion failed: ArgPackSubstIndex && "found declaration pack but not pack expanding", file C:\_work\llvm-project\llvm-project\clang\lib\Sema\SemaTemplateInstantiateDecl.cpp, line 6939
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
# | Stack dump:
# | 0.	Program arguments: c:\\_work\\llvm-project\\llvm-project\\build\\bin\\clang.exe -std=c++17 -fsyntax-only C:\\_work\\llvm-project\\llvm-project\\clang\\test\\SemaCXX\\windows_sandbox_violtion.cpp
# | 1.	C:\_work\llvm-project\llvm-project\clang\test\SemaCXX\windows_sandbox_violtion.cpp:10:14: current parser token '}'
# | Exception Code: 0xC000001D
# |  #0 0x00007ff680065596 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x805596)
# |  #1 0x00007ffdde2dbb04 (C:\Windows\System32\ucrtbase.dll+0x7bb04)
# |  #2 0x00007ffdde2dcad1 (C:\Windows\System32\ucrtbase.dll+0x7cad1)
# |  #3 0x00007ffdde2de4a1 (C:\Windows\System32\ucrtbase.dll+0x7e4a1)
# |  #4 0x00007ffdde2de6e1 (C:\Windows\System32\ucrtbase.dll+0x7e6e1)
# |  #5 0x00007ff684f45340 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x56e5340)
# |  #6 0x00007ff685081a43 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5821a43)
# |  #7 0x00007ff6850f2860 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5892860)
# |  #8 0x00007ff6850dd388 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x587d388)
# |  #9 0x00007ff6850e4c1d (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5884c1d)
# | #10 0x00007ff6850790d3 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x58190d3)
# | #11 0x00007ff6850e94f2 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x58894f2)
# | #12 0x00007ff6850f2f1c (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5892f1c)
# | #13 0x00007ff6850dd388 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x587d388)
# | #14 0x00007ff685106e80 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x58a6e80)
# | #15 0x00007ff6850e94f2 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x58894f2)
# | #16 0x00007ff6850f2f1c (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5892f1c)
# | #17 0x00007ff6850dd388 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x587d388)
# | #18 0x00007ff68507dac5 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x581dac5)
# | #19 0x00007ff6850dd4f6 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x587d4f6)
# | #20 0x00007ff685076953 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5816953)
# | #21 0x00007ff684f57d2b (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x56f7d2b)
# | #22 0x00007ff684f47b4e (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x56e7b4e)
# | #23 0x00007ff684f59c61 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x56f9c61)
# | #24 0x00007ff684f5eef9 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x56feef9)
# | #25 0x00007ff686180282 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6920282)
# | #26 0x00007ff686180916 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6920916)
# | #27 0x00007ff686181c01 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6921c01)
# | #28 0x00007ff685138ae3 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x58d8ae3)
# | #29 0x00007ff68686a264 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x700a264)
# | #30 0x00007ff68686bd1a (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x700bd1a)
# | #31 0x00007ff68685750d (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6ff750d)
# | #32 0x00007ff686856cf6 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6ff6cf6)
# | #33 0x00007ff6868503fa (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6ff03fa)
# | #34 0x00007ff686be476e (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x738476e)
# | #35 0x00007ff6867c9c74 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6f69c74)
# | #36 0x00007ff6867c6c10 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6f66c10)
# | #37 0x00007ff6865325b6 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6cd25b6)
# | #38 0x00007ff686531d8d (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6cd1d8d)
# | #39 0x00007ff686530cd4 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6cd0cd4)
# | #40 0x00007ff68652e500 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6cce500)
# | #41 0x00007ff6854ad9de (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5c4d9de)
# | #42 0x00007ff68266a02f (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x2e0a02f)
# | #43 0x00007ff6801a5e04 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x945e04)
# | #44 0x00007ff680259cfc (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x9f9cfc)
# | #45 0x00007ff67f8688a1 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x88a1)
# | #46 0x00007ff67f8641a4 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x41a4)
# | #47 0x00007ff67f866ecb (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6ecb)
# | #48 0x00007ff68243a30d (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x2bda30d)
# | #49 0x00007ff680060939 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x800939)
# | #50 0x00007ff682439946 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x2bd9946)
# | #51 0x00007ff68018bfd9 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x92bfd9)
# | #52 0x00007ff68018c28d (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x92c28d)
# | #53 0x00007ff68016a1fc (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x90a1fc)
# | #54 0x00007ff67f863540 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x3540)
# | #55 0x00007ff67f877c5c (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x17c5c)
# | #56 0x00007ff686c357e0 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x73d57e0)
# | #57 0x00007ffde1f94cb0 (C:\Windows\System32\KERNEL32.DLL+0x14cb0)
# | #58 0x00007ffdf07dedcb (C:\Windows\SYSTEM32\ntdll.dll+0x7edcb)
# | clang: error: clang frontend command failed due to signal (use -v to see invocation)
# | clang version 23.0.0git (https://github.com/llvm/llvm-project 527d6bb3625a637a8b7e716f187aa020d124de6c)
# | Target: x86_64-pc-windows-msvc
# | Thread model: posix
# | InstalledDir: C:\_work\llvm-project\llvm-project\build\bin
# | Build config: +assertions
# | clang: note: diagnostic msg: 
# | ********************
# | 
# | PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
# | Preprocessed source(s) and associated run script(s) are located at:
# | clang: note: diagnostic msg: C:\Users\ContainerAdministrator\AppData\Local\Temp\lit-tmp-m7_disau\windows_sandbox_violtion-271f02.cpp
# | clang: note: diagnostic msg: C:\Users\ContainerAdministrator\AppData\Local\Temp\lit-tmp-m7_disau\windows_sandbox_violtion-271f02.sh
# | clang: note: diagnostic msg: 
# | 
# | ********************
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/190615