[TSan][Darwin] Fix shadow mapping for iOS simulator on Apple Silicon

[yln]

Summary

With the introduction of Apple Silicon defined(__aarch64__) is not a
reliable way to check for the platform anymore.

We want to use the "normal" Mapping48AddressSpace mapping everywhere
(including the iOS simulators on AS) except on device.

Relevant revisions:
https://reviews.llvm.org/D35147
https://reviews.llvm.org/D86377
https://reviews.llvm.org/D107743
https://reviews.llvm.org/D107888

[yln]

compiler-rt/lib/tsan/rtl/tsan_platform.h

588–593

This change is NFC, but I hope it makes things easier to read.

compiler-rt/lib/tsan/rtl/tsan_platform_posix.cpp

113

iOS simulator on AS is now not included here; it will get the default mapping from the #else.

[delcypher]

LGTM

compiler-rt/lib/tsan/rtl/tsan_platform.h

588–593

It's a little hard to read but I think that's because the SANITIZER_MAC name is confusing.

compiler-rt/lib/tsan/rtl/tsan_platform.h

 #  elif defined(__aarch64__)
   return Func::template Apply<MappingGoAarch64>(arg);
 #  elif SANITIZER_WINDOWS
   return Func::template Apply<MappingGoWindows>(arg);
 #  else
   return Func::template Apply<MappingGo48>(arg);
 #  endif
 #else  // SANITIZER_GO
-#  if defined(__x86_64__) || SANITIZER_IOSSIM || SANITIZER_MAC && !SANITIZER_IOS
-  return Func::template Apply<Mapping48AddressSpace>(arg);
-#  elif defined(__aarch64__) && defined(__APPLE__)
+#  if SANITIZER_IOS && !SANITIZER_IOSSIM
   return Func::template Apply<MappingAppleAarch64>(arg);
-#  elif defined(__aarch64__) && !defined(__APPLE__)
+#  elif defined(__x86_64__) || SANITIZER_MAC
+  return Func::template Apply<Mapping48AddressSpace>(arg);
+#  elif defined(__aarch64__)
   switch (vmaSize) {
     case 39:
       return Func::template Apply<MappingAarch64_39>(arg);
     case 42:
       return Func::template Apply<MappingAarch64_42>(arg);
     case 48:
       return Func::template Apply<MappingAarch64_48>(arg);
   }
 #  elif defined(__powerpc64__)

compiler-rt/lib/tsan/rtl/tsan_platform_posix.cpp

if (segment.protection == 0)  // Zero page or mprotected.
       continue;
     if (segment.start >= VdsoBeg())  // vdso
       break;
     Printf("FATAL: ThreadSanitizer: unexpected memory mapping 0x%zx-0x%zx\n",
            segment.start, segment.end);
     Die();
   }
 
-#    if defined(__aarch64__) && defined(__APPLE__) && SANITIZER_IOS
+#    if SANITIZER_IOS && !SANITIZER_IOSSIM
   ProtectRange(HeapMemEnd(), ShadowBeg());
   ProtectRange(ShadowEnd(), MetaShadowBeg());
   ProtectRange(MetaShadowEnd(), HiAppMemBeg());
 #    else
   ProtectRange(LoAppMemEnd(), ShadowBeg());
   ProtectRange(ShadowEnd(), MetaShadowBeg());
   if (MidAppMemBeg()) {
     ProtectRange(MetaShadowEnd(), MidAppMemBeg());