[PATCH] D13782: [sanitizer] [asan] Use same shadow offset for aarch64

[Adhemerval Zanella via llvm-commits]

zatrazz created this revision.
zatrazz added reviewers: kcc, pcc, rengolin, samsonov, eugenis.
zatrazz added a subscriber: llvm-commits.
Herald added subscribers: rengolin, aemerson.

Following a discussion in gcc maillist for the libsanitizer merge I am now
trying to remove the SANITIZER_AARCH64_VMA flags for aarch64 port.

This patch makes ASAN for aarch64 use the same shadow offset for all
currently supported VMAs (39 and 42 bits).  The shadow offset is the
same of 39-bit (36). To make it work on 42-bit llvm instrumentation will
require a change [1] on how to generate the memory address.

No regression tests found in 39 and 42-bit VMA. I have not tested on 
48-bit VMA due lack of available platforms (but it is on my radar).

[1] http://reviews.llvm.org/D13781

http://reviews.llvm.org/D13782

Files:
  lib/asan/asan_mapping.h
  lib/asan/asan_rtl.cc
  lib/sanitizer_common/sanitizer_platform.h

Index: lib/sanitizer_common/sanitizer_platform.h
===================================================================
--- lib/sanitizer_common/sanitizer_platform.h
+++ lib/sanitizer_common/sanitizer_platform.h
@@ -97,23 +97,18 @@
 // For such platforms build this code with -DSANITIZER_CAN_USE_ALLOCATOR64=0 or
 // change the definition of SANITIZER_CAN_USE_ALLOCATOR64 here.
 #ifndef SANITIZER_CAN_USE_ALLOCATOR64
-# if defined(__mips64) || (defined(__aarch64__) && SANITIZER_AARCH64_VMA == 39)
+# if defined(__mips64) || defined(__aarch64__)
 #  define SANITIZER_CAN_USE_ALLOCATOR64 0
 # else
 #  define SANITIZER_CAN_USE_ALLOCATOR64 (SANITIZER_WORDSIZE == 64)
 # endif
 #endif
 
 // The range of addresses which can be returned my mmap.
-// FIXME: this value should be different on different platforms,
-// e.g. on AArch64 it is most likely (1ULL << 39). Larger values will still work
-// but will consume more memory for TwoLevelByteMap.
+// FIXME: this value should be different on different platforms.  Larger values
+// will still work but will consume more memory for TwoLevelByteMap.
 #if defined(__aarch64__)
-# if SANITIZER_AARCH64_VMA == 39
-#  define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 39)
-# elif SANITIZER_AARCH64_VMA == 42
-#  define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 42)
-# endif
+# define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 42)
 #elif defined(__mips__)
 # define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 40)
 #else
Index: lib/asan/asan_rtl.cc
===================================================================
--- lib/asan/asan_rtl.cc
+++ lib/asan/asan_rtl.cc
@@ -378,8 +378,6 @@
   // initialization steps look at flags().
   InitializeFlags();
 
-  CheckVMASize();
-
   AsanCheckIncompatibleRT();
   AsanCheckDynamicRTPrereqs();
 
Index: lib/asan/asan_mapping.h
===================================================================
--- lib/asan/asan_mapping.h
+++ lib/asan/asan_mapping.h
@@ -118,11 +118,7 @@
 static const u64 kIosShadowOffset64 = 0x130000000;
 static const u64 kIosSimShadowOffset32 = 1ULL << 30;
 static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
-#if SANITIZER_AARCH64_VMA == 39
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
-#elif SANITIZER_AARCH64_VMA == 42
-static const u64 kAArch64_ShadowOffset64 = 1ULL << 39;
-#endif
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;


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