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

[kubamracek]

Summary

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

[yln]

This means we are using dynamic shadow placement everywhere but macOS i386 and x86_64, right?

compiler-rt/lib/asan/asan_mapping.h

 #  elif SANITIZER_MYRIAD2
 #    define SHADOW_OFFSET kMyriadShadowOffset32
 #  else
 #    define SHADOW_OFFSET kDefaultShadowOffset32
 #  endif
 #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__)
 #    define SHADOW_OFFSET kPPC64_ShadowOffset64
 #  elif defined(__s390x__)
 #    define SHADOW_OFFSET kSystemZ_ShadowOffset64
 #  elif SANITIZER_FREEBSD
 #    define SHADOW_OFFSET kFreeBSD_ShadowOffset64

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

 };
 
 } // end anonymous namespace
 
 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();
   bool IsLinux = TargetTriple.isOSLinux();
   bool IsPPC64 = TargetTriple.getArch() == Triple::ppc64 ||
                  TargetTriple.getArch() == Triple::ppc64le;
   bool IsSystemZ = TargetTriple.getArch() == Triple::systemz;
   bool IsX86_64 = TargetTriple.getArch() == Triple::x86_64;
else if (IsLinux && IsX86_64) {
         Mapping.Offset = (kSmallX86_64ShadowOffsetBase &
                           (kSmallX86_64ShadowOffsetAlignMask << Mapping.Scale));
     } else if (IsWindows && IsX86_64) {
       Mapping.Offset = kWindowsShadowOffset64;
     } else if (IsMIPS64)
       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
       Mapping.Offset = kDefaultShadowOffset64;
   }
 
   if (ClForceDynamicShadow) {
     Mapping.Offset = kDynamicShadowSentinel;

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

 ; Test using dynamic shadow address on darwin
 ;
 ; RUN: opt -asan -asan-module -mtriple=arm64_32-apple-watchos --data-layout="e-m:o-p:32:32-i64:64-i128:128-n32:64-S128" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-DYNAMIC -DPTR_SIZE=32
 ; RUN: opt -asan -asan-module -mtriple=armv7k-apple-watchos --data-layout="e-m:o-p:32:32-Fi8-i64:64-a:0:32-n32-S128" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-DYNAMIC -DPTR_SIZE=32
 ; RUN: opt -asan -asan-module -mtriple=arm64-apple-ios --data-layout="e-m:o-i64:64-i128:128-n32:64-S128" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-DYNAMIC -DPTR_SIZE=64
 ; RUN: opt -asan -asan-module -mtriple=armv7s-apple-ios --data-layout="e-m:o-p:32:32-Fi8-f64:32:64-v64:32:64-v128:32:128-a:0:32-n32-S32" -S < %s | FileCheck %s --check-prefixes=CHECK,CHECK-DYNAMIC -DPTR_SIZE=32
 ; RUN: opt -asan -asan-module -mtriple=i386-apple-watchos-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=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
 ; address into a local variable.
 ; CHECK-LABEL: @test_load
 ; CHECK: entry:
 ; CHECK-DYNAMIC-NEXT: %[[SHADOW:[^ ]*]] = load i[[PTR_SIZE]], i[[PTR_SIZE]]* @__asan_shadow_memory_dynamic_address
 ; CHECK-NONDYNAMIC-NOT: __asan_shadow_memory_dynamic_address
 
 ; Shadow address is loaded and added into the whole offset computation.
 ; CHECK-DYNAMIC: add i[[PTR_SIZE]] %{{.*}}, %[[SHADOW]]
 
 entry:
   %tmp1 = load i32, i32* %a, align 4
   ret i32 %tmp1
 }