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

11 files changed, 9 insertions, 183 deletions

diff --git a/lib/asan/CMakeLists.txt b/lib/asan/CMakeLists.txt
index da82e485b..78872cd9f 100644
--- a/lib/asan/CMakeLists.txt
+++ b/lib/asan/CMakeLists.txt
@@ -21,7 +21,6 @@ set(ASAN_SOURCES
   asan_memory_profile.cc
   asan_poisoning.cc
   asan_posix.cc
-  asan_premap_shadow.cc
   asan_report.cc
   asan_rtl.cc
   asan_shadow_setup.cc
diff --git a/lib/asan/asan_init_version.h b/lib/asan/asan_init_version.h
index c49fcd740..f48cc19cc 100644
--- a/lib/asan/asan_init_version.h
+++ b/lib/asan/asan_init_version.h
@@ -15,8 +15,6 @@
 #ifndef ASAN_INIT_VERSION_H
 #define ASAN_INIT_VERSION_H
 
-#include "sanitizer_common/sanitizer_platform.h"
-
 extern "C" {
   // Every time the ASan ABI changes we also change the version number in the
   // __asan_init function name.  Objects built with incompatible ASan ABI
@@ -34,12 +32,7 @@ extern "C" {
   // v6=>v7: added 'odr_indicator' to __asan_global
   // v7=>v8: added '__asan_(un)register_image_globals' functions for dead
   //         stripping support on Mach-O platforms
-#if SANITIZER_WORDSIZE == 32 && SANITIZER_ANDROID
-  // v8=>v9: 32-bit Android switched to dynamic shadow
-  #define __asan_version_mismatch_check __asan_version_mismatch_check_v9
-#else
   #define __asan_version_mismatch_check __asan_version_mismatch_check_v8
-#endif
 }
 
 #endif  // ASAN_INIT_VERSION_H
diff --git a/lib/asan/asan_linux.cc b/lib/asan/asan_linux.cc
index 8ce4b96c2..a949a9888 100644
--- a/lib/asan/asan_linux.cc
+++ b/lib/asan/asan_linux.cc
@@ -17,7 +17,6 @@
 
 #include "asan_interceptors.h"
 #include "asan_internal.h"
-#include "asan_premap_shadow.h"
 #include "asan_thread.h"
 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_freebsd.h"
@@ -82,41 +81,9 @@ void *AsanDoesNotSupportStaticLinkage() {
   return &_DYNAMIC;  // defined in link.h
 }
 
-#if ASAN_PREMAP_SHADOW
-uptr FindPremappedShadowStart() {
-  uptr granularity = GetMmapGranularity();
-  uptr shadow_start = reinterpret_cast<uptr>(&__asan_shadow);
-  uptr shadow_size = PremapShadowSize();
-  UnmapOrDie((void *)(shadow_start - granularity), shadow_size + granularity);
-  // MmapNoAccess does not touch TotalMmap, but UnmapOrDie decreases it.
-  // Compensate.
-  IncreaseTotalMmap(shadow_size + granularity);
-  return shadow_start;
-}
-#endif
-
 uptr FindDynamicShadowStart() {
-#if ASAN_PREMAP_SHADOW
-  if (!PremapShadowFailed())
-    return FindPremappedShadowStart();
-#endif
-
-  uptr granularity = GetMmapGranularity();
-  uptr alignment = granularity * 8;
-  uptr left_padding = granularity;
-  uptr shadow_size = kHighShadowEnd + left_padding;
-  uptr map_size = shadow_size + alignment;
-
-  uptr map_start = (uptr)MmapNoAccess(map_size);
-  CHECK_NE(map_start, ~(uptr)0);
-
-  uptr shadow_start = RoundUpTo(map_start, alignment);
-  UnmapOrDie((void *)map_start, map_size);
-  // MmapNoAccess does not touch TotalMmap, but UnmapOrDie decreases it.
-  // Compensate.
-  IncreaseTotalMmap(map_size);
-
-  return shadow_start;
+  UNREACHABLE("FindDynamicShadowStart is not available");
+  return 0;
 }
 
 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
diff --git a/lib/asan/asan_mapping.h b/lib/asan/asan_mapping.h
index c51c960c5..acdaa60b9 100644
--- a/lib/asan/asan_mapping.h
+++ b/lib/asan/asan_mapping.h
@@ -161,7 +161,7 @@ static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 #  define SHADOW_OFFSET (0)
 #elif SANITIZER_WORDSIZE == 32
 #  if SANITIZER_ANDROID
-#    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
+#    define SHADOW_OFFSET (0)
 #  elif defined(__mips__)
 #    define SHADOW_OFFSET kMIPS32_ShadowOffset32
 #  elif SANITIZER_FREEBSD
@@ -205,12 +205,6 @@ static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 #  endif
 #endif
 
-#if SANITIZER_ANDROID && defined(__arm__)
-# define ASAN_PREMAP_SHADOW 1
-#else
-# define ASAN_PREMAP_SHADOW 0
-#endif
-
 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
 
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
diff --git a/lib/asan/asan_premap_shadow.h b/lib/asan/asan_premap_shadow.h
deleted file mode 100644
index 41acbdbbb..000000000
--- a/lib/asan/asan_premap_shadow.h
+++ /dev/null
@@ -1,30 +0,0 @@
-//===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
-//
-//                     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.
-//
-// Premap shadow range with an ifunc resolver.
-//===----------------------------------------------------------------------===//
-
-
-#ifndef ASAN_PREMAP_SHADOW_H
-#define ASAN_PREMAP_SHADOW_H
-
-#if ASAN_PREMAP_SHADOW
-namespace __asan {
-// Conservative upper limit.
-uptr PremapShadowSize();
-bool PremapShadowFailed();
-}
-#endif
-
-extern "C" INTERFACE_ATTRIBUTE void __asan_shadow();
-extern "C" decltype(__asan_shadow)* __asan_premap_shadow();
-
-#endif // ASAN_PREMAP_SHADOW_H
diff --git a/lib/sanitizer_common/sanitizer_common.h b/lib/sanitizer_common/sanitizer_common.h
index 746ba226c..9fb615f96 100644
--- a/lib/sanitizer_common/sanitizer_common.h
+++ b/lib/sanitizer_common/sanitizer_common.h
@@ -73,7 +73,6 @@ INLINE uptr GetPageSizeCached() {
   return PageSizeCached;
 }
 uptr GetMmapGranularity();
-uptr GetMaxVirtualAddress();
 uptr GetMaxUserVirtualAddress();
 // Threads
 tid_t GetTid();
diff --git a/lib/sanitizer_common/sanitizer_fuchsia.cc b/lib/sanitizer_common/sanitizer_fuchsia.cc
index c130c10c2..554bc458c 100644
--- a/lib/sanitizer_common/sanitizer_fuchsia.cc
+++ b/lib/sanitizer_common/sanitizer_fuchsia.cc
@@ -191,10 +191,6 @@ uptr GetMaxUserVirtualAddress() {
   return ShadowBounds.memory_limit - 1;
 }
 
-uptr GetMaxVirtualAddress() {
-  return GetMaxUserVirtualAddress();
-}
-
 static void *DoAnonymousMmapOrDie(uptr size, const char *mem_type,
                                   bool raw_report, bool die_for_nomem) {
   size = RoundUpTo(size, PAGE_SIZE);
diff --git a/lib/sanitizer_common/sanitizer_linux.cc b/lib/sanitizer_common/sanitizer_linux.cc
index 6274b248e..ea1e79556 100644
--- a/lib/sanitizer_common/sanitizer_linux.cc
+++ b/lib/sanitizer_common/sanitizer_linux.cc
@@ -954,7 +954,7 @@ static uptr GetKernelAreaSize() {
 }
 #endif  // SANITIZER_WORDSIZE == 32
 
-uptr GetMaxVirtualAddress() {
+uptr GetMaxUserVirtualAddress() {
 #if SANITIZER_NETBSD && defined(__x86_64__)
   return 0x7f7ffffff000ULL;  // (0x00007f8000000000 - PAGE_SIZE)
 #elif SANITIZER_WORDSIZE == 64
@@ -978,21 +978,15 @@ uptr GetMaxVirtualAddress() {
 # if defined(__s390__)
   return (1ULL << 31) - 1;  // 0x7fffffff;
 # else
-  return (1ULL << 32) - 1;  // 0xffffffff;
+  uptr res = (1ULL << 32) - 1;  // 0xffffffff;
+  if (!common_flags()->full_address_space)
+    res -= GetKernelAreaSize();
+  CHECK_LT(reinterpret_cast<uptr>(&res), res);
+  return res;
 # endif
 #endif  // SANITIZER_WORDSIZE
 }
 
-uptr GetMaxUserVirtualAddress() {
-  uptr addr = GetMaxVirtualAddress();
-#if SANITIZER_WORDSIZE == 32 && !defined(__s390__)
-  if (!common_flags()->full_address_space)
-    addr -= GetKernelAreaSize();
-  CHECK_LT(reinterpret_cast<uptr>(&addr), addr);
-#endif
-  return addr;
-}
-
 uptr GetPageSize() {
 // Android post-M sysconf(_SC_PAGESIZE) crashes if called from .preinit_array.
 #if SANITIZER_ANDROID
diff --git a/lib/sanitizer_common/sanitizer_mac.cc b/lib/sanitizer_common/sanitizer_mac.cc
index 195a52c47..284b6cfc7 100644
--- a/lib/sanitizer_common/sanitizer_mac.cc
+++ b/lib/sanitizer_common/sanitizer_mac.cc
@@ -864,10 +864,6 @@ uptr GetMaxUserVirtualAddress() {
 #endif  // SANITIZER_WORDSIZE
 }
 
-uptr GetMaxVirtualAddress() {
-  return GetMaxUserVirtualAddress();
-}
-
 uptr FindAvailableMemoryRange(uptr shadow_size,
                               uptr alignment,
                               uptr left_padding,
diff --git a/lib/sanitizer_common/sanitizer_win.cc b/lib/sanitizer_common/sanitizer_win.cc
index 0d72b494d..ef69ad45e 100644
--- a/lib/sanitizer_common/sanitizer_win.cc
+++ b/lib/sanitizer_common/sanitizer_win.cc
@@ -70,10 +70,6 @@ uptr GetMaxUserVirtualAddress() {
   return (uptr)si.lpMaximumApplicationAddress;
 }
 
-uptr GetMaxVirtualAddress() {
-  return GetMaxUserVirtualAddress();
-}
-
 bool FileExists(const char *filename) {
   return ::GetFileAttributesA(filename) != INVALID_FILE_ATTRIBUTES;
 }