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

Fri Oct 17 13:12:27 PDT 2025

llvm-ci wrote:

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

Full details are available at: https://lab.llvm.org/buildbot/#/builders/104/builds/33677

<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)
...
[13/784] Building CXX object libc/src/complex/generic/CMakeFiles/libc.src.complex.generic.cprojf128.dir/cprojf128.cpp.o
[14/784] Building CXX object libc/src/complex/generic/CMakeFiles/libc.src.complex.generic.cprojf.dir/cprojf.cpp.o
[15/784] Building CXX object libc/src/complex/generic/CMakeFiles/libc.src.complex.generic.creall.dir/creall.cpp.o
[16/784] Building CXX object libc/src/complex/generic/CMakeFiles/libc.src.complex.generic.crealf128.dir/crealf128.cpp.o
[17/784] Building CXX object libc/src/complex/generic/CMakeFiles/libc.src.complex.generic.cimag.dir/cimag.cpp.o
[18/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.islower.dir/islower.cpp.o
[19/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.toascii.dir/toascii.cpp.o
[20/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isgraph.dir/isgraph.cpp.o
[21/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isalnum.dir/isalnum.cpp.o
[22/784] 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/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 -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/llvm-project/libc/src/__support/StringUtil/signal_to_string.cpp
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/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.
[23/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isascii.dir/isascii.cpp.o
[24/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isdigit.dir/isdigit.cpp.o
[25/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isblank.dir/isblank.cpp.o
[26/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.iscntrl.dir/iscntrl.cpp.o
[27/784] Building CXX object libc/src/complex/generic/CMakeFiles/libc.src.complex.generic.cimagf128.dir/cimagf128.cpp.o
[28/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isalpha.dir/isalpha.cpp.o
[29/784] Building CXX object libc/src/complex/generic/CMakeFiles/libc.src.complex.generic.cproj.dir/cproj.cpp.o
[30/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isupper.dir/isupper.cpp.o
[31/784] 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/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 -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/llvm-project/libc/src/__support/StringUtil/error_to_string.cpp
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/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.
[32/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isspace.dir/isspace.cpp.o
[33/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.toupper.dir/toupper.cpp.o
[34/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.ispunct.dir/ispunct.cpp.o
[35/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isxdigit.dir/isxdigit.cpp.o
[36/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.tolower.dir/tolower.cpp.o
[37/784] Building CXX object libc/src/dlfcn/CMakeFiles/libc.src.dlfcn.dlclose.dir/dlclose.cpp.o
[38/784] Building CXX object libc/src/dlfcn/CMakeFiles/libc.src.dlfcn.dlsym.dir/dlsym.cpp.o
[39/784] Building CXX object libc/src/ctype/CMakeFiles/libc.src.ctype.isprint.dir/isprint.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