[libc-commits] [libc] [libc] Implement strftime (PR #122556)

[LLVM Continuous Integration via libc-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-x86_64-debian-gcc-fullbuild-dbg` running on `libc-x86_64-debian-fullbuild` while building `libc` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/131/builds/16056

<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)
...
[62/88] Generating header sys/types.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/types.yaml
[63/86] Generating header uchar.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/uchar.yaml
[64/86] Generating header termios.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/termios.yaml
[65/75] Generating header sys/wait.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/wait.yaml
[66/72] Generating header math.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/math.yaml
[67/72] Building CXX object compiler-rt/lib/scudo/standalone/CMakeFiles/RTScudoStandalone.x86_64.dir/mem_map_linux.cpp.o
[68/72] Building CXX object compiler-rt/lib/scudo/standalone/CMakeFiles/RTScudoStandalone.x86_64.dir/linux.cpp.o
[69/72] Building CXX object libc/src/time/CMakeFiles/libc.src.time.strftime.dir/strftime.cpp.o
[70/72] Building CXX object libc/src/time/strftime_core/CMakeFiles/libc.src.time.strftime_core.strftime_main.dir/strftime_main.cpp.o
[71/72] Building CXX object libc/src/time/strftime_core/CMakeFiles/libc.src.time.strftime_core.converter.dir/converter.cpp.o
FAILED: libc/src/time/strftime_core/CMakeFiles/libc.src.time.strftime_core.converter.dir/converter.cpp.o 
/usr/bin/g++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/libc -isystem /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -Wimplicit-fallthrough -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -fpie -ffreestanding -DLIBC_FULL_BUILD -isystem/usr/lib/gcc/x86_64-linux-gnu/12//include -nostdinc -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 -mno-omit-leaf-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -fext-numeric-literals -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -std=gnu++17 -MD -MT libc/src/time/strftime_core/CMakeFiles/libc.src.time.strftime_core.converter.dir/converter.cpp.o -MF libc/src/time/strftime_core/CMakeFiles/libc.src.time.strftime_core.converter.dir/converter.cpp.o.d -o libc/src/time/strftime_core/CMakeFiles/libc.src.time.strftime_core.converter.dir/converter.cpp.o -c /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/libc/src/time/strftime_core/converter.cpp
In file included from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/libc/src/time/strftime_core/converter.cpp:14:
/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/libc/src/time/strftime_core/composite_converter.h: In function ‘int __llvm_libc_20_0_0_git::strftime_core::convert_full_date_time(__llvm_libc_20_0_0_git::printf_core::Writer*, const FormatSection&, const tm*)’:
/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/libc/src/time/strftime_core/composite_converter.h:178:51: error: conversion from ‘long unsigned int’ to ‘int’ may change value [-Werror=conversion]
  178 |   const int requested_padding = to_conv.min_width - full_conv_len;
      |                                 ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors
ninja: build stopped: subcommand failed.
['ninja', 'libc'] exited with return code 1.
The build step threw an exception...
Traceback (most recent call last):
  File "/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 164, in step
    yield
  File "/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 126, in main
    run_command(['ninja', 'libc'])
  File "/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 179, in run_command
    util.report_run_cmd(cmd, cwd=directory)
  File "/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-zorg/zorg/buildbot/builders/annotated/util.py", line 49, in report_run_cmd
    subprocess.check_call(cmd, shell=shell, *args, **kwargs)
  File "/usr/lib/python3.11/subprocess.py", line 413, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['ninja', 'libc']' returned non-zero exit status 1.
@@@STEP_FAILURE@@@
@@@BUILD_STEP build libc-startup@@@
Running: ninja libc-startup
[1/19] Generating header errno.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/errno.yaml
[2/19] Generating header stdint.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/stdint.yaml
[3/18] Generating header fcntl.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/fcntl.yaml
[4/18] Generating header float.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/float.yaml
[5/18] Generating header limits.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/limits.yaml
[6/18] Generating header link.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/link.yaml
[7/18] Generating header sys/syscall.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/syscall.yaml
[8/18] Generating header sys/auxv.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/auxv.yaml
[9/18] Generating header sys/prctl.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/prctl.yaml
[10/18] Generating header sys/time.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/time.yaml
[11/18] Generating header time.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/time.yaml
[12/18] Generating header sys/mman.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/sys/mman.yaml
[13/17] Generating header stdlib.h from /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/llvm-project/runtimes/../libc/include/stdlib.yaml

```

</details>

https://github.com/llvm/llvm-project/pull/122556