[libc++] Refactor Windows support headers.

Summary:
This patch refactors and tries to remove as much of the Windows support headers as possible. This is needed because they currently introduce super weird include cycles and dependencies between STL and libc headers.

The changes in this patch are:

* remove `support/win32/support.h` completely. The required parts have either been moved into `support/win32/msvc_support.h` (for `MSVC` only helpers not needed by Clang), or directly into their respective `foo.h` headers.

* Combine `locale_win32.h` and `locale_mgmt_win32.h` into a single headers, this header should only be included within `__locale` or `locale` to avoid include cycles.

* Remove the unneeded parts of `limits_win32.h` and re-name it to `limits_msvc_win32.h` since it's only needed by Clang.

I've tested this patch using Clang on Windows, but I suspect it might technically regress our non-existent support for MSVC. Is somebody able to double check?

This refactor is needed to support upcoming fixes to `<locale>` on Windows.



Reviewers: bcraig, rmaprath, compnerd, EricWF

Reviewed By: EricWF

Subscribers: majnemer, cfe-commits

Differential Revision: https://reviews.llvm.org/D32988

llvm-svn: 302727

1 files changed, 0 insertions, 177 deletions

diff --git a/libcxx/include/support/win32/support.h b/libcxx/include/support/win32/support.h
deleted file mode 100644
index e48b08ddad0..00000000000
--- a/libcxx/include/support/win32/support.h
+++ /dev/null
@@ -1,177 +0,0 @@
-// -*- C++ -*-
-//===----------------------- support/win32/support.h ----------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_SUPPORT_WIN32_SUPPORT_H
-#define _LIBCPP_SUPPORT_WIN32_SUPPORT_H
-
-// Functions and constants used in libc++ that
-// are missing from the Windows C library.
-
-#include <wchar.h> // mbstate_t
-#include <cstdarg> // va_ macros
-// "builtins" not implemented here for Clang or GCC as they provide
-// implementations. Assuming required for elsewhere else, certainly MSVC.
-#if defined(_LIBCPP_COMPILER_MSVC)
-#include <intrin.h>
-#endif
-#define swprintf _snwprintf
-#define vswprintf _vsnwprintf
-
-#ifndef NOMINMAX
-#define NOMINMAX
-#endif
-
-// The mingw headers already define these as static.
-#ifndef __MINGW32__
-extern "C" {
-
-int vasprintf(char **sptr, const char *__restrict fmt, va_list ap);
-int asprintf(char **sptr, const char *__restrict fmt, ...);
-size_t mbsnrtowcs(wchar_t *__restrict dst, const char **__restrict src,
-                  size_t nmc, size_t len, mbstate_t *__restrict ps);
-size_t wcsnrtombs(char *__restrict dst, const wchar_t **__restrict src,
-                  size_t nwc, size_t len, mbstate_t *__restrict ps);
-}
-#endif // __MINGW32__
-
-#if defined(_LIBCPP_COMPILER_MSVC)
-
-// Bit builtin's make these assumptions when calling _BitScanForward/Reverse
-// etc. These assumptions are expected to be true for Win32/Win64 which this
-// file supports.
-static_assert(sizeof(unsigned long long) == 8, "");
-static_assert(sizeof(unsigned long) == 4, "");
-static_assert(sizeof(unsigned int) == 4, "");
-
-_LIBCPP_ALWAYS_INLINE int __builtin_popcount(unsigned int x)
-{
-  // Binary: 0101...
-  static const unsigned int m1 = 0x55555555;
-  // Binary: 00110011..
-  static const unsigned int m2 = 0x33333333;
-  // Binary:  4 zeros,  4 ones ...
-  static const unsigned int m4 = 0x0f0f0f0f;
-  // The sum of 256 to the power of 0,1,2,3...
-  static const unsigned int h01 = 0x01010101;
-  // Put count of each 2 bits into those 2 bits.
-  x -= (x >> 1) & m1;
-  // Put count of each 4 bits into those 4 bits.
-  x = (x & m2) + ((x >> 2) & m2);
-  // Put count of each 8 bits into those 8 bits.
-  x = (x + (x >> 4)) & m4;
-  // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24).
-  return (x * h01) >> 24;
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_popcountl(unsigned long x)
-{
-  return __builtin_popcount(static_cast<int>(x));
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_popcountll(unsigned long long x)
-{
-  // Binary: 0101...
-  static const unsigned long long m1 = 0x5555555555555555;
-  // Binary: 00110011..
-  static const unsigned long long m2 = 0x3333333333333333;
-  // Binary:  4 zeros,  4 ones ...
-  static const unsigned long long m4 = 0x0f0f0f0f0f0f0f0f;
-  // The sum of 256 to the power of 0,1,2,3...
-  static const unsigned long long h01 = 0x0101010101010101;
-  // Put count of each 2 bits into those 2 bits.
-  x -= (x >> 1) & m1;
-  // Put count of each 4 bits into those 4 bits.
-  x = (x & m2) + ((x >> 2) & m2);
-  // Put count of each 8 bits into those 8 bits.
-  x = (x + (x >> 4)) & m4;
-  // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ...
-  return static_cast<int>((x * h01) >> 56);
-}
-
-// Returns the number of trailing 0-bits in x, starting at the least significant
-// bit position. If x is 0, the result is undefined.
-_LIBCPP_ALWAYS_INLINE int __builtin_ctzll(unsigned long long mask)
-{
-  unsigned long where;
-// Search from LSB to MSB for first set bit.
-// Returns zero if no set bit is found.
-#if defined(_LIBCPP_HAS_BITSCAN64)
-    (defined(_M_AMD64) || defined(__x86_64__))
-  if (_BitScanForward64(&where, mask))
-    return static_cast<int>(where);
-#else
-  // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
-  // Scan the Low Word.
-  if (_BitScanForward(&where, static_cast<unsigned long>(mask)))
-    return static_cast<int>(where);
-  // Scan the High Word.
-  if (_BitScanForward(&where, static_cast<unsigned long>(mask >> 32)))
-    return static_cast<int>(where + 32); // Create a bit offset from the LSB.
-#endif
-  return 64;
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_ctzl(unsigned long mask)
-{
-  unsigned long where;
-  // Search from LSB to MSB for first set bit.
-  // Returns zero if no set bit is found.
-  if (_BitScanForward(&where, mask))
-    return static_cast<int>(where);
-  return 32;
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_ctz(unsigned int mask)
-{
-  // Win32 and Win64 expectations.
-  static_assert(sizeof(mask) == 4, "");
-  static_assert(sizeof(unsigned long) == 4, "");
-  return __builtin_ctzl(static_cast<unsigned long>(mask));
-}
-
-// Returns the number of leading 0-bits in x, starting at the most significant
-// bit position. If x is 0, the result is undefined.
-_LIBCPP_ALWAYS_INLINE int __builtin_clzll(unsigned long long mask)
-{
-  unsigned long where;
-// BitScanReverse scans from MSB to LSB for first set bit.
-// Returns 0 if no set bit is found.
-#if defined(_LIBCPP_HAS_BITSCAN64)
-  if (_BitScanReverse64(&where, mask))
-    return static_cast<int>(63 - where);
-#else
-  // Scan the high 32 bits.
-  if (_BitScanReverse(&where, static_cast<unsigned long>(mask >> 32)))
-    return static_cast<int>(63 -
-                            (where + 32)); // Create a bit offset from the MSB.
-  // Scan the low 32 bits.
-  if (_BitScanReverse(&where, static_cast<unsigned long>(mask)))
-    return static_cast<int>(63 - where);
-#endif
-  return 64; // Undefined Behavior.
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_clzl(unsigned long mask)
-{
-  unsigned long where;
-  // Search from LSB to MSB for first set bit.
-  // Returns zero if no set bit is found.
-  if (_BitScanReverse(&where, mask))
-    return static_cast<int>(31 - where);
-  return 32; // Undefined Behavior.
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_clz(unsigned int x)
-{
-  return __builtin_clzl(x);
-}
-#endif // _LIBCPP_MSVC
-
-#endif // _LIBCPP_SUPPORT_WIN32_SUPPORT_H