Revert "[asan] Use dynamic shadow on 32-bit Android" and 3 more.

Revert the following commits:
  r318369 [asan] Fallback to non-ifunc dynamic shadow on android<22.
  r318235 [asan] Prevent rematerialization of &__asan_shadow.
  r317948 [sanitizer] Remove unnecessary attribute hidden.
  r317943 [asan] Use dynamic shadow on 32-bit Android.

MemoryRangeIsAvailable() reads /proc/$PID/maps into an mmap-ed buffer
that may overlap with the address range that we plan to use for the
dynamic shadow mapping. This is causing random startup crashes.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@318575 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 78 deletions

diff --git a/lib/asan/asan_premap_shadow.cc b/lib/asan/asan_premap_shadow.cc
deleted file mode 100644
index 2d20c3b8c..000000000
--- a/lib/asan/asan_premap_shadow.cc
+++ /dev/null
@@ -1,78 +0,0 @@
-//===-- asan_premap_shadow.cc ---------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file is a part of AddressSanitizer, an address sanity checker.
-//
-// Reserve shadow memory with an ifunc resolver.
-//===----------------------------------------------------------------------===//
-
-#include "asan_mapping.h"
-
-#if ASAN_PREMAP_SHADOW
-
-#include "asan_premap_shadow.h"
-#include "sanitizer_common/sanitizer_posix.h"
-
-namespace __asan {
-
-// The code in this file needs to run in an unrelocated binary. It may not
-// access any external symbol, including its own non-hidden globals.
-
-// Conservative upper limit.
-uptr PremapShadowSize() {
-  return GetMaxVirtualAddress() >> SHADOW_SCALE;
-}
-
-// Returns an address aligned to 8 pages, such that one page on the left and
-// PremapShadowSize() bytes on the right of it are mapped r/o.
-uptr PremapShadow() {
-  uptr granularity = GetMmapGranularity();
-  uptr alignment = granularity * 8;
-  uptr left_padding = granularity;
-  uptr shadow_size = PremapShadowSize();
-  uptr map_size = shadow_size + left_padding + alignment;
-
-  uptr map_start = (uptr)MmapNoAccess(map_size);
-  CHECK_NE(map_start, ~(uptr)0);
-
-  uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
-  uptr shadow_end = shadow_start + shadow_size;
-  internal_munmap(reinterpret_cast<void *>(map_start),
-                  shadow_start - left_padding - map_start);
-  internal_munmap(reinterpret_cast<void *>(shadow_end),
-                  map_start + map_size - shadow_end);
-  return shadow_start;
-}
-
-bool PremapShadowFailed() {
-  uptr shadow = reinterpret_cast<uptr>(&__asan_shadow);
-  uptr resolver = reinterpret_cast<uptr>(&__asan_premap_shadow);
-  // shadow == resolver is how Android KitKat and older handles ifunc.
-  // shadow == 0 just in case.
-  if (shadow == 0 || shadow == resolver)
-    return true;
-  return false;
-}
-} // namespace __asan
-
-extern "C" {
-decltype(__asan_shadow)* __asan_premap_shadow() {
-  // The resolver may be called multiple times. Map the shadow just once.
-  static uptr premapped_shadow = 0;
-  if (!premapped_shadow) premapped_shadow = __asan::PremapShadow();
-  return reinterpret_cast<decltype(__asan_shadow)*>(premapped_shadow);
-}
-
-// __asan_shadow is a "function" that has the same address as the first byte of
-// the shadow mapping.
-INTERFACE_ATTRIBUTE __attribute__((ifunc("__asan_premap_shadow"))) void
-__asan_shadow();
-}
-
-#endif // ASAN_PREMAP_SHADOW