Revert "[tsan] Use large address space mapping on Apple Silicon Macs"

This reverts commit bde2e56071.

This patch produces a compile failure on linux amd64 environments, when
running:

  ninja GotsanRuntimeCheck

I get various build errors:

  ../rtl/tsan_platform.h:608: error: use of undeclared identifier 'Mapping'
    return MappingImpl<Mapping, Type>();

Here's a buildbot with the same failure during stage "check-tsan in gcc
build", there are other unrelated failures in there.

  http://lab.llvm.org:8011/#/builders/37/builds/2831

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

@@ -26,18 +26,6 @@ namespace __tsan {
 #if !SANITIZER_GO
 
 #if defined(__x86_64__)
-#define HAS_48_BIT_ADDRESS_SPACE 1
-#elif SANITIZER_IOSSIM // arm64 iOS simulators (order of #if matters)
-#define HAS_48_BIT_ADDRESS_SPACE 1
-#elif SANITIZER_IOS // arm64 iOS devices (order of #if matters)
-#define HAS_48_BIT_ADDRESS_SPACE 0
-#elif SANITIZER_MAC // arm64 macOS (order of #if matters)
-#define HAS_48_BIT_ADDRESS_SPACE 1
-#else
-#define HAS_48_BIT_ADDRESS_SPACE 0
-#endif
-
-#if HAS_48_BIT_ADDRESS_SPACE
 /*
 C/C++ on linux/x86_64 and freebsd/x86_64
 0000 0000 1000 - 0080 0000 0000: main binary and/or MAP_32BIT mappings (512GB)
@@ -158,7 +146,7 @@ struct Mapping {
   static const uptr kVdsoBeg       = 0x7000000000000000ull;
 };
 
-#elif defined(__aarch64__) && !defined(__APPLE__)
+#elif defined(__aarch64__)
 // AArch64 supports multiple VMA which leads to multiple address transformation
 // functions.  To support these multiple VMAS transformations and mappings TSAN
 // runtime for AArch64 uses an external memory read (vmaSize) to select which
@@ -366,7 +354,7 @@ struct Mapping47 {
 #define TSAN_RUNTIME_VMA 1
 #endif
 
-#elif SANITIZER_GO && !SANITIZER_WINDOWS && HAS_48_BIT_ADDRESS_SPACE
+#elif SANITIZER_GO && !SANITIZER_WINDOWS && defined(__x86_64__)
 
 /* Go on linux, darwin and freebsd on x86_64
 0000 0000 1000 - 0000 1000 0000: executable

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

@@ -234,7 +234,7 @@ static void my_pthread_introspection_hook(unsigned int event, pthread_t thread,
 #endif
 
 void InitializePlatformEarly() {
-#if !SANITIZER_GO && !HAS_48_BIT_ADDRESS_SPACE
+#if !SANITIZER_GO && defined(__aarch64__)
   uptr max_vm = GetMaxUserVirtualAddress() + 1;
   if (max_vm != Mapping::kHiAppMemEnd) {
     Printf("ThreadSanitizer: unsupported vm address limit %p, expected %p.\n",

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

@@ -99,7 +99,7 @@ void CheckAndProtect() {
     Die();
   }
 
-#if defined(__aarch64__) && !HAS_48_BIT_ADDRESS_SPACE
+#if defined(__aarch64__) && defined(__APPLE__)
   ProtectRange(HeapMemEnd(), ShadowBeg());
   ProtectRange(ShadowEnd(), MetaShadowBeg());
   ProtectRange(MetaShadowEnd(), TraceMemBeg());