[asan] Use dynamic shadow memory position on Apple Silicon macOS

This is needed because macOS on Apple Silicon has some reserved pages inside the "regular" shadow memory location, and mapping over that location fails.

Differential Revision: https://reviews.llvm.org/D82912

Author: kubamracek

compiler-rt/lib/asan/asan_mapping.h

@@ -206,6 +206,8 @@ static const u64 kMyriadCacheBitMask32 = 0x40000000ULL;
 #else
 #  if SANITIZER_IOS
 #    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
+#  elif SANITIZER_MAC && defined(__aarch64__)
+#    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
 #  elif defined(__aarch64__)
 #    define SHADOW_OFFSET kAArch64_ShadowOffset64
 #  elif defined(__powerpc64__)

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -434,6 +434,7 @@ static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
                                       bool IsKasan) {
   bool IsAndroid = TargetTriple.isAndroid();
   bool IsIOS = TargetTriple.isiOS() || TargetTriple.isWatchOS();
+  bool IsMacOS = TargetTriple.isMacOSX();
   bool IsFreeBSD = TargetTriple.isOSFreeBSD();
   bool IsNetBSD = TargetTriple.isOSNetBSD();
   bool IsPS4CPU = TargetTriple.isPS4CPU();
@@ -510,6 +511,8 @@ static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
       Mapping.Offset = kMIPS64_ShadowOffset64;
     else if (IsIOS)
       Mapping.Offset = kDynamicShadowSentinel;
+    else if (IsMacOS && IsAArch64)
+      Mapping.Offset = kDynamicShadowSentinel;
     else if (IsAArch64)
       Mapping.Offset = kAArch64_ShadowOffset64;
     else

llvm/test/Instrumentation/AddressSanitizer/dynamic-shadow-darwin.ll

@@ -8,8 +8,10 @@
 ; RUN: opt -asan -asan-module -mtriple=i386-apple-ios-simulator --data-layout="e-m:o-p:32:32-f64:32:64-f80:128-n8:16:32-S128" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-DYNAMIC -DPTR_SIZE=32
 ; RUN: opt -asan -asan-module -mtriple=x86_64-apple-ios-simulator --data-layout="e-m:o-i64:64-f80:128-n8:16:32:64-S128" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-DYNAMIC -DPTR_SIZE=64
 ;
-; // macOS does not use dynamic shadow placement
+; // macOS does not use dynamic shadow placement on x86_64
 ; RUN: opt -asan -asan-module -mtriple=x86_64-apple-macosx --data-layout="e-m:o-i64:64-f80:128-n8:16:32:64-S128" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-NONDYNAMIC -DPTR_SIZE=64
+; // macOS does use dynamic shadow placement on arm64
+; RUN: opt -asan -asan-module -mtriple=arm64-apple-macosx --data-layout="e-m:o-i64:64-i128:128-n32:64-S128" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-DYNAMIC -DPTR_SIZE=64
 
 define i32 @test_load(i32* %a) sanitize_address {
 ; First instrumentation in the function must be to load the dynamic shadow