[libc] gcc build failures on github action runners

[SchrodingerZhu]

These were spotted in #119104.

The first one is at https://github.com/llvm/llvm-project/actions/runs/12217700280/job/34082285018?pr=119104

In file included from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/linux/syscall.h:13,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/syscall.h:15,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/pread.cpp:11:
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/pread.cpp:21:29: error: ‘ssize_t __llvm_libc_20_0_0_git::pread(int, void*, size_t, off_t)’ aliased to external symbol ‘pread’
[ 92%] Built target libc.src.unistd.linux.lseek
   21 | LLVM_LIBC_FUNCTION(ssize_t, pread,
      |                             ^~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/common.h:46:34: note: in definition of macro ‘LLVM_LIBC_FUNCTION_IMPL’
   46 |   decltype(LIBC_NAMESPACE::name) name [[gnu::alias(#name)]];                   \
      |                                  ^~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/pread.cpp:21:1: note: in expansion of macro ‘LLVM_LIBC_FUNCTION’
   21 | LLVM_LIBC_FUNCTION(ssize_t, pread,
      | ^~~~~~~~~~~~~~~~~~
gmake[2]: *** [libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.pread.dir/build.make:79: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.pread.dir/pread.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:147979: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.pread.dir/all] Error 2
[ 92%] Built target libc.src.unistd.linux.link
[ 92%] Built target libc.src.unistd.linux.pipe
[ 92%] Built target libc.src.unistd.linux.pwrite
[ 92%] Built target libc.src.unistd.linux.linkat
[ 92%] Built target libc.src.unistd.linux.pipe2
In file included from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/linux/syscall.h:13,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/syscall.h:15,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlinkat.cpp:11:
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlinkat.cpp:21:29: error: ‘ssize_t __llvm_libc_20_0_0_git::readlinkat(int, const char*, char*, size_t)’ aliased to external symbol ‘readlinkat’
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlinkat,
      |                             ^~~~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/common.h:46:34: note: in definition of macro ‘LLVM_LIBC_FUNCTION_IMPL’
   46 |   decltype(LIBC_NAMESPACE::name) name [[gnu::alias(#name)]];                   \
      |                                  ^~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlinkat.cpp:21:1: note: in expansion of macro ‘LLVM_LIBC_FUNCTION’
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlinkat,
      | ^~~~~~~~~~~~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlinkat.cpp:21:29: error: ‘ssize_t __llvm_libc_20_0_0_git::readlinkat(int, const char*, char*, size_t)’ specifies less restrictive attributes than its target ‘ssize_t readlinkat(int, const char*, char*, size_t)’: ‘leaf’, ‘nonnull’, ‘nothrow’ [-Werror=missing-attributes]
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlinkat,
      |                             ^~~~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/common.h:46:34: note: in definition of macro ‘LLVM_LIBC_FUNCTION_IMPL’
   46 |   decltype(LIBC_NAMESPACE::name) name [[gnu::alias(#name)]];                   \
      |                                  ^~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlinkat.cpp:21:1: note: in expansion of macro ‘LLVM_LIBC_FUNCTION’
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlinkat,
      | ^~~~~~~~~~~~~~~~~~
In file included from /usr/include/features.h:486,
                 from /usr/include/unistd.h:25,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/readlinkat.h:13,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlinkat.cpp:9:
/usr/include/x86_64-linux-gnu/bits/unistd.h:144:1: note: ‘ssize_t __llvm_libc_20_0_0_git::readlinkat(int, const char*, char*, size_t)’ target declared here
  144 | __NTH (readlinkat (int __fd, const char *__restrict __path,
      | ^~~~~
cc1plus: all warnings being treated as errors
gmake[2]: *** [libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.readlinkat.dir/build.make:79: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.readlinkat.dir/readlinkat.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:148299: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.readlinkat.dir/all] Error 2
[ 92%] Built target libc.src.unistd.linux.rmdir
In file included from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/linux/syscall.h:13,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/syscall.h:15,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlink.cpp:11:
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlink.cpp:21:29: error: ‘ssize_t __llvm_libc_20_0_0_git::readlink(const char*, char*, size_t)’ aliased to external symbol ‘readlink’
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlink,
      |                             ^~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/common.h:46:34: note: in definition of macro ‘LLVM_LIBC_FUNCTION_IMPL’
   46 |   decltype(LIBC_NAMESPACE::name) name [[gnu::alias(#name)]];                   \
      |                                  ^~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlink.cpp:21:1: note: in expansion of macro ‘LLVM_LIBC_FUNCTION’
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlink,
      | ^~~~~~~~~~~~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlink.cpp:21:29: error: ‘ssize_t __llvm_libc_20_0_0_git::readlink(const char*, char*, size_t)’ specifies less restrictive attributes than its target ‘ssize_t readlink(const char*, char*, size_t)’: ‘leaf’, ‘nonnull’, ‘nothrow’ [-Werror=missing-attributes]
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlink,
      |                             ^~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/common.h:46:34: note: in definition of macro ‘LLVM_LIBC_FUNCTION_IMPL’
   46 |   decltype(LIBC_NAMESPACE::name) name [[gnu::alias(#name)]];                   \
      |                                  ^~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlink.cpp:21:1: note: in expansion of macro ‘LLVM_LIBC_FUNCTION’
   21 | LLVM_LIBC_FUNCTION(ssize_t, readlink,
      | ^~~~~~~~~~~~~~~~~~
In file included from /usr/include/features.h:486,
                 from /usr/include/unistd.h:25,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/readlink.h:13,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/readlink.cpp:9:
/usr/include/x86_64-linux-gnu/bits/unistd.h:116:1: note: ‘ssize_t __llvm_libc_20_0_0_git::readlink(const char*, char*, size_t)’ target declared here
  116 | __NTH (readlink (const char *__restrict __path, char *__restrict __buf,
      | ^~~~~
cc1plus: all warnings being treated as errors
gmake[2]: *** [libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.readlink.dir/build.make:79: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.readlink.dir/readlink.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:148235: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.readlink.dir/all] Error 2
[ 92%] Built target libc.src.unistd.linux.symlinkat
[ 92%] Built target libc.src.unistd.linux.symlink
[ 92%] Built target libc.src.unistd.linux.unlinkat
[ 92%] Built target libc.src.unistd.linux.truncate
In file included from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/linux/syscall.h:13,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/__support/OSUtil/syscall.h:15,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/getcwd.cpp:11:
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/getcwd.cpp:38:28: error: ‘char* __llvm_libc_20_0_0_git::getcwd(char*, size_t)’ aliased to external symbol ‘getcwd’
   38 | LLVM_LIBC_FUNCTION(char *, getcwd, (char *buf, size_t size)) {
      |                            ^~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/common.h:46:34: note: in definition of macro ‘LLVM_LIBC_FUNCTION_IMPL’
   46 |   decltype(LIBC_NAMESPACE::name) name [[gnu::alias(#name)]];                   \
      |                                  ^~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/getcwd.cpp:38:1: note: in expansion of macro ‘LLVM_LIBC_FUNCTION’
   38 | LLVM_LIBC_FUNCTION(char *, getcwd, (char *buf, size_t size)) {
      | ^~~~~~~~~~~~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/getcwd.cpp:38:28: error: ‘char* __llvm_libc_20_0_0_git::getcwd(char*, size_t)’ specifies less restrictive attributes than its target ‘char* getcwd(char*, size_t)’: ‘leaf’, ‘nothrow’ [-Werror=missing-attributes]
   38 | LLVM_LIBC_FUNCTION(char *, getcwd, (char *buf, size_t size)) {
      |                            ^~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/common.h:46:34: note: in definition of macro ‘LLVM_LIBC_FUNCTION_IMPL’
   46 |   decltype(LIBC_NAMESPACE::name) name [[gnu::alias(#name)]];                   \
      |                                  ^~~~
/home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/getcwd.cpp:38:1: note: in expansion of macro ‘LLVM_LIBC_FUNCTION’
   38 | LLVM_LIBC_FUNCTION(char *, getcwd, (char *buf, size_t size)) {
      | ^~~~~~~~~~~~~~~~~~
In file included from /usr/include/features.h:486,
                 from /usr/include/unistd.h:25,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/getcwd.h:13,
                 from /home/runner/work/llvm-project/llvm-project/libc/src/unistd/linux/getcwd.cpp:9:
/usr/include/x86_64-linux-gnu/bits/unistd.h:164:1: note: ‘char* __llvm_libc_20_0_0_git::getcwd(char*, size_t)’ target declared here
  164 | __NTH (getcwd (char *__buf, size_t __size))
      | ^~~~~
cc1plus: all warnings being treated as errors
gmake[2]: *** [libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.getcwd.dir/build.make:79: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.getcwd.dir/getcwd.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:147175: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.getcwd.dir/all] Error 2
gmake: *** [Makefile:136: all] Error 2

The second one is at https://github.com/llvm/llvm-project/actions/runs/12218362957/job/34083763790?pr=119104

FAILED: libc/src/math/generic/CMakeFiles/libc.src.math.generic.sinf16.dir/sinf16.cpp.o 
sccache /usr/bin/g++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -I/home/runner/work/llvm-project/llvm-project/libc -isystem /home/runner/work/llvm-project/llvm-project/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 -ffunction-sections -fdata-sections -O2 -g -DNDEBUG -std=gnu++17 -mavx2 -mfma -msse4.2 -D__LIBC_USE_BUILTIN_CEIL_FLOOR_RINT_TRUNC -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -fpie -ffreestanding -DLIBC_FULL_BUILD -isystem/usr/lib/gcc/x86_64-linux-gnu/13//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 -fext-numeric-literals -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -O3 -DLIBC_COPT_PUBLIC_PACKAGING -MD -MT libc/src/math/generic/CMakeFiles/libc.src.math.generic.sinf16.dir/sinf16.cpp.o -MF libc/src/math/generic/CMakeFiles/libc.src.math.generic.sinf16.dir/sinf16.cpp.o.d -o libc/src/math/generic/CMakeFiles/libc.src.math.generic.sinf16.dir/sinf16.cpp.o -c /home/runner/work/llvm-project/llvm-project/libc/src/math/generic/sinf16.cpp
In file included from /home/runner/work/llvm-project/llvm-project/libc/src/math/generic/sinf16.cpp:16:
/home/runner/work/llvm-project/llvm-project/libc/src/__support/FPUtil/except_value_utils.h: In instantiation of ‘constexpr __llvm_libc_20_0_0_git::cpp::optional<T> __llvm_libc_20_0_0_git::fputil::ExceptValues<T, N>::lookup_odd(StorageType, bool) const [with T = _Float16; long unsigned int N = 4; StorageType = short unsigned int]’:
/home/runner/work/llvm-project/llvm-project/libc/src/math/generic/sinf16.cpp:60:43:   required from here
/home/runner/work/llvm-project/llvm-project/libc/src/__support/FPUtil/except_value_utils.h:84:20: error: conversion from ‘int’ to ‘__llvm_libc_20_0_0_git::fputil::ExceptValues<_Float16, 4>::StorageType’ {aka ‘short unsigned int’} may change value [-Werror=conversion]
   84 |           out_bits += sign ? values[i].rnd_downward_offset
      |           ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   85 |                            : values[i].rnd_upward_offset;
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/__support/FPUtil/except_value_utils.h:88:20: error: conversion from ‘int’ to ‘__llvm_libc_20_0_0_git::fputil::ExceptValues<_Float16, 4>::StorageType’ {aka ‘short unsigned int’} may change value [-Werror=conversion]
   88 |           out_bits += sign ? values[i].rnd_upward_offset
      |           ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   89 |                            : values[i].rnd_downward_offset;
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors

[nickdesaulniers]

The second one seems straightforward to fix.

The first one is a duplicate of #60481.

[SchrodingerZhu]

In that case, once these are fixed, it seems good to enable the gcc ci to capture future build issues like this.

[nickdesaulniers]

Let's track the second issue at #120427.