[libc-commits] [libc] [libc] add basic lifetime annotations for support data structures (PR #145933)

Fri Oct 17 13:12:43 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-aarch64-ubuntu-fullbuild-dbg` running on `libc-aarch64-ubuntu` while building `libc` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/71/builds/33651

<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/libc-linux.py ...' (failure)
...
-- check-runtimes does nothing.
-- Configuring done
-- Generating done
-- Build files have been written to: /home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/build
@@@BUILD_STEP build libc@@@
Running: ninja libc
[1/532] Building CXX object libc/src/__support/CPP/CMakeFiles/libc.src.__support.CPP.new.dir/new.cpp.o
[2/532] Building CXX object libc/src/__support/OSUtil/linux/CMakeFiles/libc.src.__support.OSUtil.linux.linux_util.dir/exit.cpp.o
[3/532] Building CXX object libc/src/__support/OSUtil/linux/CMakeFiles/libc.src.__support.OSUtil.linux.linux_util.dir/fcntl.cpp.o
[4/532] Building CXX object libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.signal_to_string.dir/signal_to_string.cpp.o
FAILED: libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.signal_to_string.dir/signal_to_string.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/llvm-project/libc -isystem libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -Wno-pass-failed -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -DLIBC_THREAD_MODE=LIBC_THREAD_MODE_PLATFORM -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -std=gnu++17 -MD -MT libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.signal_to_string.dir/signal_to_string.cpp.o -MF libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.signal_to_string.dir/signal_to_string.cpp.o.d -o libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.signal_to_string.dir/signal_to_string.cpp.o -c /home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/llvm-project/libc/src/__support/StringUtil/signal_to_string.cpp
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/llvm-project/libc/src/__support/StringUtil/signal_to_string.cpp:75:13: error: address of stack memory associated with local variable 'opt_str' returned [-Werror,-Wreturn-stack-address]
    return *opt_str;
            ^~~~~~~
1 error generated.
[5/532] Building CXX object libc/src/stdio/generic/CMakeFiles/libc.src.stdio.generic.ferror_unlocked.dir/ferror_unlocked.cpp.o
[6/532] Building CXX object libc/src/stdio/linux/CMakeFiles/libc.src.stdio.linux.fdopen.dir/fdopen.cpp.o
[7/532] Building CXX object libc/src/__support/File/linux/CMakeFiles/libc.src.__support.File.linux.stdout.dir/stdout.cpp.o
[8/532] Building CXX object libc/src/__support/File/linux/CMakeFiles/libc.src.__support.File.linux.stdin.dir/stdin.cpp.o
[9/532] Building CXX object libc/src/__support/OSUtil/linux/CMakeFiles/libc.src.__support.OSUtil.linux.vdso.dir/vdso.cpp.o
[10/532] Building CXX object libc/src/stdio/CMakeFiles/libc.src.stdio.fopencookie.dir/fopencookie.cpp.o
[11/532] Building CXX object libc/src/__support/threads/linux/CMakeFiles/libc.src.__support.threads.linux.CndVar.dir/CndVar.cpp.o
[12/532] Building CXX object libc/src/__support/File/CMakeFiles/libc.src.__support.File.dir.dir/dir.cpp.o
[13/532] Building CXX object libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.error_to_string.dir/error_to_string.cpp.o
FAILED: libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.error_to_string.dir/error_to_string.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/llvm-project/libc -isystem libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -Wno-pass-failed -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -DLIBC_THREAD_MODE=LIBC_THREAD_MODE_PLATFORM -fpie -ffreestanding -DLIBC_FULL_BUILD -nostdlibinc -idirafter/usr/include -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -std=gnu++17 -MD -MT libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.error_to_string.dir/error_to_string.cpp.o -MF libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.error_to_string.dir/error_to_string.cpp.o.d -o libc/src/__support/StringUtil/CMakeFiles/libc.src.__support.StringUtil.error_to_string.dir/error_to_string.cpp.o -c /home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/llvm-project/libc/src/__support/StringUtil/error_to_string.cpp
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/llvm-project/libc/src/__support/StringUtil/error_to_string.cpp:75:13: error: address of stack memory associated with local variable 'opt_str' returned [-Werror,-Wreturn-stack-address]
    return *opt_str;
            ^~~~~~~
1 error generated.
[14/532] Building CXX object libc/src/__support/threads/CMakeFiles/libc.src.__support.threads.fork_callbacks.dir/fork_callbacks.cpp.o
[15/532] Building CXX object libc/src/stdio/generic/CMakeFiles/libc.src.stdio.generic.fread_unlocked.dir/fread_unlocked.cpp.o
[16/532] Building CXX object libc/src/stdio/generic/CMakeFiles/libc.src.stdio.generic.fputc.dir/fputc.cpp.o
[17/532] Building CXX object libc/src/__support/File/linux/CMakeFiles/libc.src.__support.File.linux.stderr.dir/stderr.cpp.o
[18/532] Building CXX object libc/src/__support/File/CMakeFiles/libc.src.__support.File.file.dir/file.cpp.o
[19/532] Building CXX object libc/src/__support/File/linux/CMakeFiles/libc.src.__support.File.linux.file.dir/file.cpp.o
[20/532] Building CXX object libc/src/__support/threads/linux/CMakeFiles/libc.src.__support.threads.linux.thread.dir/thread.cpp.o
[21/532] Building CXX object libc/src/__support/threads/CMakeFiles/libc.src.__support.threads.thread.dir/thread.cpp.o
ninja: build stopped: subcommand failed.
['ninja', 'libc'] exited with return code 1.
The build step threw an exception...
Traceback (most recent call last):
  File "../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 181, in step
    yield
  File "../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 143, in main
    run_command(['ninja', 'libc'])
  File "../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 196, in run_command
    util.report_run_cmd(cmd, cwd=directory)

```

</details>

https://github.com/llvm/llvm-project/pull/145933