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Remove non-standard use of std::exception in compiler-rt/test/asan/TestCases/Windows/basic_exception_handling.cpp#164137

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thurstond merged 1 commit intollvm:mainfrom
davidmrdavid:dev/dajusto/remove-non-standard-exception-test
Oct 19, 2025
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Remove non-standard use of std::exception in compiler-rt/test/asan/TestCases/Windows/basic_exception_handling.cpp#164137
thurstond merged 1 commit intollvm:mainfrom
davidmrdavid:dev/dajusto/remove-non-standard-exception-test

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@davidmrdavid davidmrdavid commented Oct 19, 2025

Follow up to: #159618

Context

The linked PR ^ introduced a new test to ensure that ASan on Windows no longer instruments catch-parameters. This test used a non-standard constructor of std::exception,one that accepted strings as their input, which somehow passed the PR CI but would fail to compile on mingw with libc++.

This was originally reported by @mstorsjo, in this comment:

This testcase fails to compile in mingw environments, with libc++ as a C++ standard library - https://github.com/mstorsjo/llvm-mingw/actions/runs/18608410056/job/53074081871:

D:\a\llvm-mingw\llvm-mingw\llvm-project\compiler-rt\test\asan\TestCases\Windows\basic_exception_handling.cpp:11:32: error: no matching conversion for functional-style cast from 'const char[6]' to 'std::exception'
   11 | void throwInFunction() { throw std::exception("test2"); }
      |                                ^~~~~~~~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:75:25: note: candidate constructor not viable: no known conversion from 'const char[6]' to 'const exception' for 1st argument
   75 |   _LIBCPP_HIDE_FROM_ABI exception(const exception&) _NOEXCEPT            = default;
      |                         ^         ~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:74:25: note: candidate constructor not viable: requires 0 arguments, but 1 was provided
   74 |   _LIBCPP_HIDE_FROM_ABI exception() _NOEXCEPT {}
      |                         ^
D:\a\llvm-mingw\llvm-mingw\llvm-project\compiler-rt\test\asan\TestCases\Windows\basic_exception_handling.cpp:16:11: error: no matching conversion for functional-style cast from 'const char[6]' to 'std::exception'
   16 |     throw std::exception("test1");
      |           ^~~~~~~~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:75:25: note: candidate constructor not viable: no known conversion from 'const char[6]' to 'const exception' for 1st argument
   75 |   _LIBCPP_HIDE_FROM_ABI exception(const exception&) _NOEXCEPT            = default;
      |                         ^         ~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:74:25: note: candidate constructor not viable: requires 0 arguments, but 1 was provided
   74 |   _LIBCPP_HIDE_FROM_ABI exception() _NOEXCEPT {}
      |                         ^
2 errors generated.
Looking at https://en.cppreference.com/w/cpp/error/exception/exception.html, I don't see any std::exception constructor taking a const char* parameter.

from: #159618 (comment)

This PR adjusts the faulty test case to rely on std::runtime_error, which contains a standard constructor accepting a string. This should suffice to make the test pass on mingw. I tested this on godbolt: https://godbolt.org/z/M4hPv5Wvx

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llvmbot commented Oct 19, 2025

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: David Justo (davidmrdavid)

Changes

Follow up to: #159618

Context

The linked PR ^ introduced a new test to ensure that ASan on Windows no longer instruments catch-parameters. This test used a non-standard constructor of std::exception,one that accepted strings as their input, which somehow passed the PR CI but would fail to compile on mingw with libc++.

This was originally reported by @mstorsjo, in this comment:

This testcase fails to compile in mingw environments, with libc++ as a C++ standard library - https://github.com/mstorsjo/llvm-mingw/actions/runs/18608410056/job/53074081871:

D:\a\llvm-mingw\llvm-mingw\llvm-project\compiler-rt\test\asan\TestCases\Windows\basic_exception_handling.cpp:11:32: error: no matching conversion for functional-style cast from 'const char[6]' to 'std::exception'
   11 | void throwInFunction() { throw std::exception("test2"); }
      |                                ^~~~~~~~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:75:25: note: candidate constructor not viable: no known conversion from 'const char[6]' to 'const exception' for 1st argument
   75 |   _LIBCPP_HIDE_FROM_ABI exception(const exception&) _NOEXCEPT            = default;
      |                         ^         ~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:74:25: note: candidate constructor not viable: requires 0 arguments, but 1 was provided
   74 |   _LIBCPP_HIDE_FROM_ABI exception() _NOEXCEPT {}
      |                         ^
D:\a\llvm-mingw\llvm-mingw\llvm-project\compiler-rt\test\asan\TestCases\Windows\basic_exception_handling.cpp:16:11: error: no matching conversion for functional-style cast from 'const char[6]' to 'std::exception'
   16 |     throw std::exception("test1");
      |           ^~~~~~~~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:75:25: note: candidate constructor not viable: no known conversion from 'const char[6]' to 'const exception' for 1st argument
   75 |   _LIBCPP_HIDE_FROM_ABI exception(const exception&) _NOEXCEPT            = default;
      |                         ^         ~~~~~~~~~~~~~~~~
C:/llvm-mingw/include/c++/v1/__exception/exception.h:74:25: note: candidate constructor not viable: requires 0 arguments, but 1 was provided
   74 |   _LIBCPP_HIDE_FROM_ABI exception() _NOEXCEPT {}
      |                         ^
2 errors generated.
Looking at https://en.cppreference.com/w/cpp/error/exception/exception.html, I don't see any std::exception constructor taking a const char* parameter.

from: #159618 (comment)

This PR adjusts the faulty test case to rely on std::runtime_error, which contains a standard constructor accepting a string. This should suffice to make the test pass on mingw. I tested this on godbolt: https://godbolt.org/z/M4hPv5Wvx

Full diff: https://github.com/llvm/llvm-project/pull/164137.diff

1 Files Affected:

  • (modified) compiler-rt/test/asan/TestCases/Windows/basic_exception_handling.cpp (+3-2)
diff --git a/compiler-rt/test/asan/TestCases/Windows/basic_exception_handling.cpp b/compiler-rt/test/asan/TestCases/Windows/basic_exception_handling.cpp
index 6f028147c9049..8d1b9ef17393f 100644
--- a/compiler-rt/test/asan/TestCases/Windows/basic_exception_handling.cpp
+++ b/compiler-rt/test/asan/TestCases/Windows/basic_exception_handling.cpp
@@ -7,13 +7,14 @@
 // This code is based on the repro in https://github.com/google/sanitizers/issues/749
 #include <cstdio>
 #include <exception>
+#include <stdexcept>
 
-void throwInFunction() { throw std::exception("test2"); }
+void throwInFunction() { throw std::runtime_error("test2"); }
 
 int main() {
   // case 1: direct throw
   try {
-    throw std::exception("test1");
+    throw std::runtime_error("test1");
   } catch (const std::exception &ex) {
     puts(ex.what());
     // CHECK: test1

@davidmrdavid davidmrdavid mentioned this pull request Oct 19, 2025
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thurstond commented Oct 19, 2025

Thanks for the fix-forward!

Btw, some quirks of LLVM:

  • 'You are allowed to commit patches without approval which you think are obvious. This is clearly a subjective decision — we simply expect you to use good judgement. Examples include: fixing build breakage, reverting obviously broken patches, documentation/comment changes, any other minor changes.'
  • 'we tend to make much heavier use of reverts to keep the tree healthy than some other open source projects, and our norms are a bit different. ... Any time you learn of a serious problem with a change, you should revert it. We strongly encourage “revert to green” as opposed to “fixing forward”. We encourage reverting first, investigating offline, and then reapplying the fixed patch - possibly after another round of review if warranted.'
    (https://llvm.org/docs/DeveloperPolicy.html)

@thurstond thurstond merged commit 52f5683 into llvm:main Oct 19, 2025
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davidmrdavid commented Oct 19, 2025

thanks for the info! Next time I'll do a quick revert, and fix later. Got it!

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