[compiler-rt] r364105 - [ASan] Use dynamic shadow on 32-bit iOS and simulators

[Julian Lettner via llvm-commits]

Author: yln
Date: Fri Jun 21 14:01:39 2019
New Revision: 364105

URL: http://llvm.org/viewvc/llvm-project?rev=364105&view=rev
Log:
[ASan] Use dynamic shadow on 32-bit iOS and simulators

The VM layout on iOS is not stable between releases. On 64-bit iOS and
its derivatives we use a dynamic shadow offset that enables ASan to
search for a valid location for the shadow heap on process launch rather
than hardcode it.

This commit extends that approach for 32-bit iOS plus derivatives and
their simulators.

rdar://50645192
rdar://51200372
rdar://51767702

Reviewed By: delcypher

Differential Revision: https://reviews.llvm.org/D63586

Modified:
    compiler-rt/trunk/lib/asan/asan_mapping.h
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc

Modified: compiler-rt/trunk/lib/asan/asan_mapping.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_mapping.h?rev=364105&r1=364104&r2=364105&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_mapping.h (original)
+++ compiler-rt/trunk/lib/asan/asan_mapping.h Fri Jun 21 14:01:39 2019
@@ -160,10 +160,6 @@ static const u64 kDefaultShadowOffset32
 static const u64 kDefaultShadowOffset64 = 1ULL << 44;
 static const u64 kDefaultShort64bitShadowOffset =
     0x7FFFFFFF & (~0xFFFULL << kDefaultShadowScale);  // < 2G.
-static const u64 kIosShadowOffset32 = 1ULL << 30;  // 0x40000000
-static const u64 kIosShadowOffset64 = 0x120200000;
-static const u64 kIosSimShadowOffset32 = 1ULL << 30;
-static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
@@ -201,11 +197,7 @@ static const u64 kMyriadCacheBitMask32 =
 #  elif SANITIZER_WINDOWS
 #    define SHADOW_OFFSET kWindowsShadowOffset32
 #  elif SANITIZER_IOS
-#    if SANITIZER_IOSSIM
-#      define SHADOW_OFFSET kIosSimShadowOffset32
-#    else
-#      define SHADOW_OFFSET kIosShadowOffset32
-#    endif
+#    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
 #  elif SANITIZER_MYRIAD2
 #    define SHADOW_OFFSET kMyriadShadowOffset32
 #  else
@@ -213,11 +205,7 @@ static const u64 kMyriadCacheBitMask32 =
 #  endif
 #else
 #  if SANITIZER_IOS
-#    if SANITIZER_IOSSIM
-#      define SHADOW_OFFSET kIosSimShadowOffset64
-#    else
-#      define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
-#    endif
+#    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
 #  elif defined(__aarch64__)
 #    define SHADOW_OFFSET kAArch64_ShadowOffset64
 #  elif defined(__powerpc64__)

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc?rev=364105&r1=364104&r2=364105&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc Fri Jun 21 14:01:39 2019
@@ -912,7 +912,7 @@ char **GetArgv() {
   return *_NSGetArgv();
 }
 
-#if defined(__aarch64__) && SANITIZER_IOS && !SANITIZER_IOSSIM
+#if SANITIZER_IOS
 // The task_vm_info struct is normally provided by the macOS SDK, but we need
 // fields only available in 10.12+. Declare the struct manually to be able to
 // build against older SDKs.
@@ -943,33 +943,37 @@ struct __sanitizer_task_vm_info {
 #define __SANITIZER_TASK_VM_INFO_COUNT ((mach_msg_type_number_t) \
     (sizeof(__sanitizer_task_vm_info) / sizeof(natural_t)))
 
-uptr GetTaskInfoMaxAddress() {
+static uptr GetTaskInfoMaxAddress() {
   __sanitizer_task_vm_info vm_info = {} /* zero initialize */;
   mach_msg_type_number_t count = __SANITIZER_TASK_VM_INFO_COUNT;
   int err = task_info(mach_task_self(), TASK_VM_INFO, (int *)&vm_info, &count);
-  if (err == 0 && vm_info.max_address != 0) {
-    return vm_info.max_address - 1;
-  } else {
-    // xnu cannot provide vm address limit
-    return 0x200000000 - 1;
-  }
+  return err ? 0 : vm_info.max_address;
 }
-#endif
 
 uptr GetMaxUserVirtualAddress() {
-#if SANITIZER_WORDSIZE == 64
-# if defined(__aarch64__) && SANITIZER_IOS && !SANITIZER_IOSSIM
-  // Get the maximum VM address
   static uptr max_vm = GetTaskInfoMaxAddress();
-  CHECK(max_vm);
-  return max_vm;
+  if (max_vm != 0)
+    return max_vm - 1;
+
+  // xnu cannot provide vm address limit
+# if SANITIZER_WORDSIZE == 32
+  return 0xffe00000 - 1;
 # else
-  return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
+  return 0x200000000 - 1;
 # endif
-#else  // SANITIZER_WORDSIZE == 32
+}
+
+#else // !SANITIZER_IOS
+
+uptr GetMaxUserVirtualAddress() {
+# if SANITIZER_WORDSIZE == 64
+  return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
+# else // SANITIZER_WORDSIZE == 32
+  static_assert(SANITIZER_WORDSIZE == 32, "Wrong wordsize");
   return (1ULL << 32) - 1;  // 0xffffffff;
-#endif  // SANITIZER_WORDSIZE
+# endif
 }
+#endif
 
 uptr GetMaxVirtualAddress() {
   return GetMaxUserVirtualAddress();