[libc++] Remove workarounds for systems that used to require __need_XXX macros

[ldionne]

Summary

Libc++ tried accomodating systems that need to be able to define various
__need_FOO macros before including C library headers, however it does not
appear to be needed anymore in most cases. Indeed, glibc used to use that
system to conditionally provide definitions, however almost all instances
of these macros have been removed from glibc years ago.

This is a reapplication of 119cef40d18c, which was reverted in 3f65c8fcbe4e
because it broke some builders.

[ldionne]

I am expecting CI to let me know whether these workarounds are still needed.

[ldionne]

Fix issues.

[ldionne]

Hopefully fix CI.

[philnik]

LGTM % nit with CI passing.

libcxx/include/ext/__hash

18

Why not <cstddef> like we do everywhere else?

[ldionne]

Rebase onto main.

[ldionne]

Try to fix GCC issues

[ldionne]

libcxx/include/ext/__hash

18

I remember why I had included <stddef.h> now -- it's because this file uses size_t instead of std::size_t and that breaks the module build if we include <cstddef> instead of <stddef.h>.

[ldionne]

Include <stddef.h> instead of <cstddef>

[ldionne]

AIX is stuck but the rest is passing.

[gulfem]

We started seeing failures while compiling some libcxx/src/ files:

FAILED: libcxx/src/CMakeFiles/cxx_static.dir/barrier.cpp.o 
/b/s/w/ir/cache/goma/client/gomacc /b/s/w/ir/x/w/staging/llvm_build/./bin/clang++ --target=aarch64-unknown-linux-gnu --sysroot=/b/s/w/ir/x/w/cipd/linux -DLIBCXX_BUILDING_LIBCXXABI -D_LIBCPP_BUILDING_LIBRARY -D_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS -D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER -D_LIBCPP_LINK_PTHREAD_LIB -D_LIBCPP_LINK_RT_LIB -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src -I/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1 -I/b/s/w/ir/x/w/staging/llvm_build/include/aarch64-unknown-linux-gnu/c++/v1 -I/b/s/w/ir/x/w/llvm-llvm-project/libcxxabi/include --target=aarch64-unknown-linux-gnu -fPIC -fno-semantic-interposition -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 -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -ffile-prefix-map=/b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-aarch64-unknown-linux-gnu-bins=../staging/llvm_build/runtimes/runtimes-aarch64-unknown-linux-gnu-bins -ffile-prefix-map=/b/s/w/ir/x/w/llvm-llvm-project/= -no-canonical-prefixes -O2 -g  -UNDEBUG -faligned-allocation -nostdinc++ -fvisibility-inlines-hidden -fvisibility=hidden -Wall -Wextra -W -Wwrite-strings -Wno-unused-parameter -Wno-long-long -Werror=return-type -Wextra-semi -Wundef -Wformat-nonliteral -Wno-user-defined-literals -Wno-covered-switch-default -Wno-suggest-override -Wno-error -std=c++20 -MD -MT libcxx/src/CMakeFiles/cxx_static.dir/barrier.cpp.o -MF libcxx/src/CMakeFiles/cxx_static.dir/barrier.cpp.o.d -o libcxx/src/CMakeFiles/cxx_static.dir/barrier.cpp.o -c /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/barrier.cpp
In file included from /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/barrier.cpp:14:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/thread:90:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__mutex_base:20:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/system_error:154:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/string:561:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__string/char_traits.h:24:
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/cstdio:160:9: error: target of using declaration conflicts with declaration already in scope
using ::remove _LIBCPP_USING_IF_EXISTS;
        ^
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/cstdio:160:1: note: target of using declaration
using ::remove _LIBCPP_USING_IF_EXISTS;
^
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__algorithm/remove.h:25:1: note: conflicting declaration
remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
^
In file included from /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/barrier.cpp:14:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/thread:90:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__mutex_base:20:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/system_error:154:
In file included from /b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/string:561:
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__string/char_traits.h:81:26: error: use of undeclared identifier 'EOF'
        {return int_type(EOF);}
                         ^
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__string/char_traits.h:80:47: error: no return statement in constexpr function
    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
                                              ^
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__string/char_traits.h:257:26: error: use of undeclared identifier 'EOF'
        {return int_type(EOF);}
                         ^
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__string/char_traits.h:256:47: error: no return statement in constexpr function
    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
                                              ^
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__string/char_traits.h:482:26: error: use of undeclared identifier 'EOF'
        {return int_type(EOF);}
                         ^
/b/s/w/ir/x/w/staging/llvm_build/include/c++/v1/__string/char_traits.h:481:38: error: no return statement in constexpr function
    static inline constexpr int_type eof() noexcept
                                     ^
7 errors generated.

https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8796880526532247985/+/u/clang/build/stdout

[glandium]

Also getting errors when building compiler-rt standalone:

[task 2022-11-21T21:07:28.272Z] In file included from /builds/worker/fetches/llvm-project/libcxx/src/mutex.cpp:11:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/mutex:192:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/__mutex_base:20:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/system_error:154:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/string:561:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/__string/char_traits.h:24:
[task 2022-11-21T21:07:28.272Z] include/c++/v1/cstdio:160:9: error: target of using declaration conflicts with declaration already in scope
[task 2022-11-21T21:07:28.272Z] using ::remove _LIBCPP_USING_IF_EXISTS;
[task 2022-11-21T21:07:28.272Z]         ^
[task 2022-11-21T21:07:28.272Z] include/c++/v1/cstdio:160:1: note: target of using declaration
[task 2022-11-21T21:07:28.272Z] using ::remove _LIBCPP_USING_IF_EXISTS;
[task 2022-11-21T21:07:28.272Z] ^
[task 2022-11-21T21:07:28.272Z] include/c++/v1/__algorithm/remove.h:25:1: note: conflicting declaration
[task 2022-11-21T21:07:28.272Z] remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
[task 2022-11-21T21:07:28.272Z] ^
[task 2022-11-21T21:07:28.272Z] In file included from /builds/worker/fetches/llvm-project/libcxx/src/mutex.cpp:11:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/mutex:192:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/__mutex_base:20:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/system_error:154:
[task 2022-11-21T21:07:28.272Z] In file included from include/c++/v1/string:561:
[task 2022-11-21T21:07:28.272Z] include/c++/v1/__string/char_traits.h:81:26: error: use of undeclared identifier 'EOF'
[task 2022-11-21T21:07:28.272Z]         {return int_type(EOF);}
[task 2022-11-21T21:07:28.272Z]                          ^
[task 2022-11-21T21:07:28.272Z] include/c++/v1/__string/char_traits.h:80:47: error: no return statement in constexpr function
[task 2022-11-21T21:07:28.272Z]     static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
[task 2022-11-21T21:07:28.272Z]                                               ^
[task 2022-11-21T21:07:28.272Z] include/c++/v1/__string/char_traits.h:257:26: error: use of undeclared identifier 'EOF'
[task 2022-11-21T21:07:28.272Z]         {return int_type(EOF);}
[task 2022-11-21T21:07:28.272Z]                          ^
[task 2022-11-21T21:07:28.272Z] include/c++/v1/__string/char_traits.h:256:47: error: no return statement in constexpr function
[task 2022-11-21T21:07:28.272Z]     static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
[task 2022-11-21T21:07:28.272Z]                                               ^
[task 2022-11-21T21:07:28.272Z] include/c++/v1/__string/char_traits.h:482:26: error: use of undeclared identifier 'EOF'
[task 2022-11-21T21:07:28.272Z]         {return int_type(EOF);}
[task 2022-11-21T21:07:28.272Z]                          ^
[task 2022-11-21T21:07:28.272Z] include/c++/v1/__string/char_traits.h:481:38: error: no return statement in constexpr function
[task 2022-11-21T21:07:28.272Z]     static inline constexpr int_type eof() noexcept
[task 2022-11-21T21:07:28.272Z]                                      ^
[task 2022-11-21T21:07:28.272Z] 7 errors generated.
[task 2022-11-21T21:07:28.577Z] [880/906] Building CXX object libcxx/src/CMakeFiles/cxx_static.dir/random_shuffle.cpp.o

[glandium]

(using a sysroot that contains glibc 2.19)

[uabelho]

We also see errors with this patch, compiling on a clean tree. First error:

[1/29] Building CXX object libcxx/src/CMakeFiles/cxx_static.dir/system_error.cpp.o
FAILED: libcxx/src/CMakeFiles/cxx_static.dir/system_error.cpp.o 
/repo/uabelho/main-github/llvm/build-all-builtins/./bin/clang++ --target=x86_64-unknown-linux-gnu -DLIBCXX_BUILDING_LIBCXXABI -D_LIBCPP_BUILDING_LIBRARY -D_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS -D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS="" -D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER -D_LIBCPP_LINK_PTHREAD_LIB -D_LIBCPP_LINK_RT_LIB -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/repo/uabelho/main-github/libcxx/src -Iinclude/c++/v1 -I/repo/uabelho/main-github/libcxxabi/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 -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3  -fPIC -faligned-allocation -nostdinc++ -fvisibility-inlines-hidden -fvisibility=hidden -Wall -Wextra -W -Wwrite-strings -Wno-unused-parameter -Wno-long-long -Werror=return-type -Wextra-semi -Wundef -Wformat-nonliteral -Wno-user-defined-literals -Wno-covered-switch-default -Wno-suggest-override -Wno-error -fno-exceptions -std=c++20 -MD -MT libcxx/src/CMakeFiles/cxx_static.dir/system_error.cpp.o -MF libcxx/src/CMakeFiles/cxx_static.dir/system_error.cpp.o.d -o libcxx/src/CMakeFiles/cxx_static.dir/system_error.cpp.o -c /repo/uabelho/main-github/libcxx/src/system_error.cpp
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:218:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:218:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:219:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    wstreampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:219:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    wstreampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:221:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    u8streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:221:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    u8streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:223:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    u16streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:223:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    u16streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:224:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    u32streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:548:
In file included from include/c++/v1/__ios/fpos.h:14:
include/c++/v1/iosfwd:224:14: error: reference to unresolved using declaration
typedef fpos<mbstate_t>    u32streampos;
             ^
include/c++/v1/__mbstate_t.h:40:1: note: using declaration annotated with 'using_if_exists' here
using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
^
In file included from /repo/uabelho/main-github/libcxx/src/system_error.cpp:19:
In file included from include/c++/v1/string:561:
In file included from include/c++/v1/__string/char_traits.h:29:
In file included from include/c++/v1/cwchar:107:
In file included from include/c++/v1/cwctype:56:
In file included from include/c++/v1/wctype.h:67:
/usr/include/wctype.h:111:22: error: unknown type name 'wint_t'
extern int iswalnum (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:117:22: error: unknown type name 'wint_t'
extern int iswalpha (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:120:22: error: unknown type name 'wint_t'
extern int iswcntrl (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:124:22: error: unknown type name 'wint_t'
extern int iswdigit (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:128:22: error: unknown type name 'wint_t'
extern int iswgraph (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:133:22: error: unknown type name 'wint_t'
extern int iswlower (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:136:22: error: unknown type name 'wint_t'
extern int iswprint (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:141:22: error: unknown type name 'wint_t'
extern int iswpunct (wint_t __wc) __THROW;
                     ^
/usr/include/wctype.h:146:22: error: unknown type name 'wint_t'
extern int iswspace (wint_t __wc) __THROW;
                     ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

[arichardson]

libcxx/include/stddef.h

36

I don't believe this is true: running clang -nostdinc -P -E ~/llvm-project/clang/lib/Headers/stddef.h gives me the following output:

typedef long int ptrdiff_t;
typedef long unsigned int size_t;
typedef int wchar_t;
typedef struct {
  long long __clang_max_align_nonce1
      __attribute__((__aligned__(__alignof__(long long))));
  long double __clang_max_align_nonce2
      __attribute__((__aligned__(__alignof__(long double))));
} max_align_t;

And running with -dD shows that NULL is also defined.

The only thing that explicitly needs a __need macro appears to be __need_wint_t (added in rGa8792e514a4e271a61b8cc7e3e39485fb00af2bf)

[kongyi]

+1 seeing build errors on Android build bots (glibc 2.17 sysroot). I'm reverting this change given it is affecting multiple developers and has been one business day without a fix.

[ldionne]

Folks who encountered failures: Please paste the CMake configuration and the system you're on. All of our CI passed with this patch so there's nothing I can do about it unless you paste the configuration you are using and the system you're on.

[ldionne]

Reupload without any __need_XXX macros

[jyknight]

FWIW, the purpose of all the gunk in stddef.h was to allow a libc implementation to retrieve only a particular subset of the names from the compiler-provided stddef.h. E.g. stdlib.h is specified to define size_t and wchar_t, but not ptrdiff_t/etc. Whether that level of pedantic namespace cleanliness is ever actually useful seems...questionable. But, someone felt it was a useful goal at some point, at least.

For C++ code, though, I really doubt it can matter -- we're already pretty-much hosed in terms of namespace pollution by unconditionally setting __GNU_SOURCE. What's a few more extraneous names after all that?

(Of course, making a standard header which supports magic defines to modify its behavior was a pretty yucky way to have implemented this libc/compiler cooperation. And we have a better way for the compiler to communicate these types to libc, anyways -- the built-in __PTRDIFF_TYPE__, __SIZE_TYPE__, __WINT_TYPE__, etc.)

But -- for this simplification to work, I think at minimum it needs to undef each of these macros before the include_next -- in order to ensure that it's NOT getting any header subsets from the include_next.

Otherwise, you break code like

#define __need_ptrdiff_t 1
// intended to define only ptrdiff_t.
#include <stddef.h>
...
// Now include full stddef.h...but this hits libc++ stddef.h's header guard, and becomes a no-op
#include <stddef.h>

I think the minimal implementation is to undef each of the "need" macros before the #include_next <stddef.h>. And the same for each of the other affected headers.

[gulfem]

In D131425#3943886, @ldionne wrote:

Folks who encountered failures: Please paste the CMake configuration and the system you're on. All of our CI passed with this patch so there's nothing I can do about it unless you paste the configuration you are using and the system you're on.

Here's our CMake configuration, and please let me know if you need help to reproduce it locally.
https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8796880526532247985/+/u/clang/configure/execution_details

[uabelho]

In D131425#3942906, @uabelho wrote:

We also see errors with this patch, compiling on a clean tree. First error:

[...]

cmake:

cmake command: CC='/proj/flexasic/app/llvm/8.0/bin/clang -march=corei7 --gcc-toolchain=/proj/bbi_twh/wh_bbi/x86_64-Linux2/bbigcc/1.9.3.0/crosscompiler' CXX='/proj/flexasic/app/llvm/8.0/bin/clang++ -march=corei7 --gcc-toolchain=/proj/bbi_twh/wh_bbi/x86_64-Linux2/bbigcc/1.9.3.0/crosscompiler' LDFLAGS='-Wl,-R/proj/bbi_twh/wh_bbi/x86_64-Linux3/z3/4.8.8-1/lib64' PATH=/app/vbuild/RHEL7-x86_64/ninja/1.10.2/bin:$PATH  /app/vbuild/RHEL7-x86_64/cmake/3.20.1/bin/cmake /repo/uabelho/main-github/llvm --debug-trycompile -G Ninja -DCMAKE_MAKE_PROGRAM=/app/vbuild/RHEL7-x86_64/ninja/1.10.2/bin/ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_FLAGS='-Wno-error=unused-command-line-argument' -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_INSTALL_PREFIX=/compiler-clang -DLLVM_APPEND_VC_REV=ON -DLLVM_CCACHE_BUILD=OFF -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ENABLE_WERROR=ON -DLLVM_ENABLE_PROJECTS='clang;clang-tools-extra;lld' -DLLVM_BUILTIN_TARGETS='x86_64-unknown-linux-gnu' -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON -DLLVM_ENABLE_RUNTIMES='libcxx;libcxxabi;libunwind;compiler-rt' -DRUNTIMES_x86_64-unknown-linux-gnu_SANITIZER_USE_STATIC_LLVM_UNWINDER=ON -DRUNTIMES_x86_64-unknown-linux-gnu_SANITIZER_USE_STATIC_CXX_ABI=ON -DRUNTIMES_x86_64-unknown-linux-gnu_COMPILER_RT_USE_BUILTINS_LIBRARY=ON -DRUNTIMES_x86_64-unknown-linux-gnu_COMPILER_RT_CAN_EXECUTE_TESTS=OFF -DRUNTIMES_x86_64-unknown-linux-gnu_COMPILER_RT_BUILD_XRAY=OFF -DRUNTIMES_x86_64-unknown-linux-gnu_COMPILER_RT_BUILD_ORC=OFF -DLLVM_RUNTIME_TARGETS='x86_64-unknown-linux-gnu' -DLLVM_ENABLE_Z3_SOLVER=ON -DLLVM_Z3_INSTALL_DIR=/proj/bbi_twh/wh_bbi/x86_64-Linux3/z3/4.8.8-1 -DLLVM_ENABLE_LIBPFM=OFF -DLLVM_ENABLE_LIBXML2=OFF -DLLVM_ENABLE_TERMINFO=OFF -DLLVM_ENABLE_LIBEDIT=OFF -DLLVM_STATIC_LINK_CXX_STDLIB=ON -DCLANG_ENABLE_ARCMT=OFF -DCLANG_TOOLING_BUILD_AST_INTROSPECTION=OFF

sysroot glibc 2.17

libcxx/include/ext/__hash

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_EXT_HASH
 #define _LIBCPP_EXT_HASH
 
 #  pragma GCC system_header
 
 #include <__config>
+#include <cstddef>
 #include <cstring>
 #include <string>
 
 namespace __gnu_cxx {
 
 template <typename _Tp> struct _LIBCPP_TEMPLATE_VIS hash { };
 
 template <> struct _LIBCPP_TEMPLATE_VIS hash<const char*>
  : public std::__unary_function<const char*, size_t>
 {

libcxx/include/module.modulemap.in

module depr [extern_c] {
     module stdint_h {
       header "stdint.h"
       export *
       // FIXME: This module only exists on OS X and for some reason the
       // wildcard above doesn't export it.
       export Darwin.C.stdint
     }
     module stdio_h {
-      // <stdio.h>'s __need_* macros require textual inclusion.
-      textual header "stdio.h"
+      header "stdio.h"
       export *
       export Darwin.C.stdio
     }
     module stdlib_h {
-      // <stdlib.h>'s __need_* macros require textual inclusion.
-      textual header "stdlib.h"
+      header "stdlib.h"
       export *
     }
     module string_h {
       header "string.h"
       export *
     }
     module uchar_h {
       header "uchar.h"
       export *
     }
     // <time.h> provided by C library.
     module wchar_h {
       @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
-      // <wchar.h>'s __need_* macros require textual inclusion.
-      textual header "wchar.h"
+      header "wchar.h"
       export *
     }
     module wctype_h {
       @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
       header "wctype.h"
       export *
     }
   }

libcxx/include/stdbool.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
+
 #ifndef _LIBCPP_STDBOOL_H
 #define _LIBCPP_STDBOOL_H
 
 /*
     stdbool.h synopsis
 
 Macros:
 

libcxx/include/stddef.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-#if defined(__need_ptrdiff_t) || defined(__need_size_t) || \
-    defined(__need_wchar_t) || defined(__need_NULL) || defined(__need_wint_t)
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-#include_next <stddef.h>
-
-#elif !defined(_LIBCPP_STDDEF_H)
+#ifndef _LIBCPP_STDDEF_H
 #define _LIBCPP_STDDEF_H
 
 /*
     stddef.h synopsis
 
 Macros:
 
     offsetof(type,member-designator)

 */
 
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
-#  if __has_include_next(<stddef.h>)
-#    include_next <stddef.h>
-#  endif
+// The Clang builtin headers only define the types we need when we request it explicitly.
+// TODO: We should fix that in Clang and drop these defines.
+#ifndef __need_ptrdiff_t
+#  define __need_ptrdiff_t
+#endif
+#ifndef __need_size_t
+#  define __need_size_t
+#endif
+#ifndef __need_wchar_t
+#  define __need_wchar_t
+#endif
+#ifndef __need_NULL
+#  define __need_NULL
+#endif
+#ifndef __need_STDDEF_H_misc
+#  define __need_STDDEF_H_misc
+#endif
+
+#if __has_include_next(<stddef.h>)
+#  include_next <stddef.h>
+#endif
 
 #ifdef __cplusplus
     typedef decltype(nullptr) nullptr_t;
 #endif
 
 #endif // _LIBCPP_STDDEF_H

libcxx/include/stdio.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-#if defined(__need_FILE) || defined(__need___FILE)
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-#include_next <stdio.h>
-
-#elif !defined(_LIBCPP_STDIO_H)
+#ifndef _LIBCPP_STDIO_H
 #define _LIBCPP_STDIO_H
 
 /*
     stdio.h synopsis
 
 Macros:
 
     BUFSIZ

libcxx/include/stdlib.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-#if defined(__need_malloc_and_calloc)
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-#include_next <stdlib.h>
-
-#elif !defined(_LIBCPP_STDLIB_H)
+#ifndef _LIBCPP_STDLIB_H
 #define _LIBCPP_STDLIB_H
 
 /*
     stdlib.h synopsis
 
 Macros:
 
     EXIT_FAILURE

libcxx/include/wchar.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-#if defined(__need_wint_t) || defined(__need_mbstate_t)
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-#include_next <wchar.h>
-
-#elif !defined(_LIBCPP_WCHAR_H)
+#ifndef _LIBCPP_WCHAR_H
 #define _LIBCPP_WCHAR_H
 
 /*
     wchar.h synopsis
 
 Macros:
 
     NULL