Subzero. Removes X8664_STACK_HACK from the crosstests.

crosstest/stack_hack.x8664.c

-//===- subzero/crosstest/stack_hack.x8664.c - X8664 stack hack ------------===//
-//
-//                        The Subzero Code Generator
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// Implements main() for crosstests in x86-64.
-//
-//===----------------------------------------------------------------------===//
-#include <assert.h>
-#include <stdint.h>
-
-#include <sys/mman.h>
-
-// X8664_STACK_HACK needs to be defined before xdefs.h is included.
-#define X8664_STACK_HACK
-#include "xdefs.h"
-
-/// xSetStack is used to set %rsp to NewRsp. OldRsp is a pointer that will be
-/// used to save the old %rsp value.
-#define xSetStack(NewRsp, OldRsp)                                              \
-  do {                                                                         \
-    __asm__ volatile("xchgq   %1, %%rsp\n\t"                                   \
-                     "xchgq   %1, %0"                                          \
-                     : "=r"(*(OldRsp))                                         \
-                     : "r"(NewRsp));                                           \
-  } while (0)
-
-extern int wrapped_main(int argc, char *argv[]);
-
-unsigned char *xStackStart(uint32 StackEnd, uint32 Size) {
-  const uint32 PageBoundary = 4 << 20; // 4 MB.
-  const uint64 StackStart = StackEnd - Size;
-  assert(StackStart + (PageBoundary - 1) & ~(PageBoundary - 1) &&
-         "StackStart not aligned to page boundary.");
-  (void)PageBoundary;
-  assert((StackStart & 0xFFFFFFFF00000000ull) == 0 && "StackStart wraps.");
-  return (unsigned char *)StackStart;
-}
-
-unsigned char *xAllocStack(uint64 StackEnd, uint32 Size) {
-  assert((StackEnd & 0xFFFFFFFF00000000ull) == 0 && "Invalid StackEnd.");
-  void *Stack =
-      mmap(xStackStart(StackEnd, Size), Size, PROT_READ | PROT_WRITE,
-           MAP_FIXED | MAP_PRIVATE | MAP_GROWSDOWN | MAP_ANONYMOUS, -1, 0);
-  assert(Stack != MAP_FAILED && "mmap failed. no stack.");
-  return Stack;
-}
-
-void xDeallocStack(uint64 StackEnd, uint32 Size) {
-  assert((StackEnd & 0xFFFFFFFF00000000ull) == 0 && "Invalid StackEnd.");
-  munmap(xStackStart(StackEnd, Size), Size);
-}
-
-int main(int argc, char *argv[]) {
-  // These "locals" need to live **NOT** in the stack.
-  static int Argc;
-  static char **Argv;
-  static const uint32_t StackEnd = 0x80000000;
-  static const uint32_t StackSize = 40 * 1024 * 1024;
-  static unsigned char *new_rsp;
-  static unsigned char *old_rsp;
-  static unsigned char *dummy_rsp;
-  static int Failures;
-  Argc = argc;
-  Argv = argv;
-  new_rsp = xAllocStack(StackEnd, StackSize) + StackSize;
-  xSetStack(new_rsp, &old_rsp);
-  Failures = wrapped_main(Argc, Argv);
-  xSetStack(old_rsp, &new_rsp);
-  xDeallocStack(StackEnd, StackSize);
-  return Failures;
-}