[PATCH] D12747: Implement [depr.c.headers]

[Richard Smith via cfe-commits]

rsmith created this revision.
rsmith added reviewers: mclow.lists, EricWF, chandlerc.
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rsmith set the repository for this revision to rL LLVM.

This patch provides the <foo.h> headers required by [depr.c.headers]. Previously, libc++ would rely on the underlying C library to provide these files, but it provides the C versions of the headers which typically miss some overloads required for a C++ standard library, and define macros that the C++ headers are not permitted to define.

I also removed some code which did this:

    #ifdef isxdigit
    inline _LIBCPP_INLINE_VISIBILITY int __libcpp_isxdigit(int __c) {return isxdigit(__c);}
    #undef isxdigit
    inline _LIBCPP_INLINE_VISIBILITY int isxdigit(int __c) {return __libcpp_isxdigit(__c);}
    #endif  // isxdigit

This doesn't work when defining the function in the global namespace (there already is a function named `isxdigit` in that scope), and is not necessary for correctness -- the C standard requires that these symbols are defined as functions, even if there's a macro present. So instead we just use this:

    #undef isxdigit

This theoretically produces slower code, in that the macro may do something that's faster than a function call. However, in at least glibc, the libc function is defined as an inline function anyway (when building at -O1 or above), so there is no actual difference.

Repository:
  rL LLVM

http://reviews.llvm.org/D12747

Files:
  include/__nullptr
  include/cctype
  include/cerrno
  include/cfloat
  include/cinttypes
  include/cmath
  include/csetjmp
  include/cstddef
  include/cstdio
  include/cstdlib
  include/cstring
  include/ctype.h
  include/cwchar
  include/cwctype
  include/deque
  include/errno.h
  include/float.h
  include/inttypes.h
  include/math.h
  include/module.modulemap
  include/setjmp.h
  include/stddef.h
  include/stdio.h
  include/stdlib.h
  include/string.h
  include/wchar.h
  include/wctype.h
  lib/buildit
  test/std/depr/depr.c.headers/inttypes_h.pass.cpp
  test/std/depr/depr.c.headers/math_h.pass.cpp
  test/std/depr/depr.c.headers/math_h_isinf.pass.cpp
  test/std/depr/depr.c.headers/math_h_isnan.pass.cpp
  test/std/depr/depr.c.headers/setjmp_h.pass.cpp
  test/std/depr/depr.c.headers/stddef_h.pass.cpp
  test/std/depr/depr.c.headers/stdio_h.pass.cpp
  test/std/depr/depr.c.headers/stdlib_h.pass.cpp
  test/std/depr/depr.c.headers/wchar_h.pass.cpp
  test/std/strings/c.strings/cctype.pass.cpp

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