[asan] Add the FreeBSD AArch64 shadow offset to llvm

[andrew]

Summary

AArch64 has a larger address space than 64 but x86. Use the larger
shadow offset on FreeBSD AArch64.

[andrew]

Enable the FreeBSD llvm asan test on AArch64

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

 static const uint64_t kSystemZ_ShadowOffset64 = 1ULL << 52;
 static const uint64_t kMIPS_ShadowOffsetN32 = 1ULL << 29;
 static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
 static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 37;
 static const uint64_t kAArch64_ShadowOffset64 = 1ULL << 36;
 static const uint64_t kRISCV64_ShadowOffset64 = 0xd55550000;
 static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
+static const uint64_t kFreeBSDAArch64_ShadowOffset64 = 1ULL << 47;
 static const uint64_t kFreeBSDKasan_ShadowOffset64 = 0xdffff7c000000000;
 static const uint64_t kNetBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kNetBSD_ShadowOffset64 = 1ULL << 46;
 static const uint64_t kNetBSDKasan_ShadowOffset64 = 0xdfff900000000000;
 static const uint64_t kPS_ShadowOffset64 = 1ULL << 40;
 static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
 static const uint64_t kEmscriptenShadowOffset = 0;
 
if (LongSize == 32) {
     // Fuchsia is always PIE, which means that the beginning of the address
     // space is always available.
     if (IsFuchsia)
       Mapping.Offset = 0;
     else if (IsPPC64)
       Mapping.Offset = kPPC64_ShadowOffset64;
     else if (IsSystemZ)
       Mapping.Offset = kSystemZ_ShadowOffset64;
+    else if (IsFreeBSD && IsAArch64)
+        Mapping.Offset = kFreeBSDAArch64_ShadowOffset64;
     else if (IsFreeBSD && !IsMIPS64) {
       if (IsKasan)
         Mapping.Offset = kFreeBSDKasan_ShadowOffset64;
       else
         Mapping.Offset = kFreeBSD_ShadowOffset64;
     } else if (IsNetBSD) {
       if (IsKasan)
         Mapping.Offset = kNetBSDKasan_ShadowOffset64;

llvm/test/Instrumentation/AddressSanitizer/freebsd.ll

 ; RUN: opt < %s -passes='asan-pipeline' -S \
 ; RUN:     -mtriple=i386-unknown-freebsd \
 ; RUN:     -data-layout="e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128" | \
 ; RUN:     FileCheck --check-prefix=CHECK-32 %s
 
 ; RUN: opt < %s -passes='asan-pipeline' -S \
 ; RUN:     -mtriple=x86_64-unknown-freebsd \
 ; RUN:     -data-layout="e-m:e-i64:64-f80:128-n8:16:32:64-S128" | \
 ; RUN:     FileCheck --check-prefix=CHECK-64 %s
 
 ; RUN: opt < %s -passes='asan-pipeline' -S \
+; RUN:     -mtriple=aarch64-unknown-freebsd \
+; RUN:     -data-layout="e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128" | \
+; RUN:     FileCheck --check-prefix=CHECK-AARCH64 %s
+
+; RUN: opt < %s -passes='asan-pipeline' -S \
 ; RUN:     -mtriple=mips64-unknown-freebsd \
 ; RUN:     -data-layout="E-m:e-i64:64-n32:64-S128" | \
 ; RUN:     FileCheck --check-prefix=CHECK-MIPS64 %s
 
 define i32 @read_4_bytes(i32* %a) sanitize_address {
 entry:
   %tmp1 = load i32, i32* %a, align 4
   ret i32 %tmp1
 }
 
 ; CHECK-32: @read_4_bytes
 ; CHECK-32-NOT: ret
 ; Check for ASAN's Offset for 32-bit (2^30 or 0x40000000)
 ; CHECK-32: lshr {{.*}} 3
 ; CHECK-32-NEXT: {{1073741824}}
 ; CHECK-32: ret
 
 ; CHECK-64: @read_4_bytes
 ; CHECK-64-NOT: ret
 ; Check for ASAN's Offset for 64-bit (2^46 or 0x400000000000)
 ; CHECK-64: lshr {{.*}} 3
 ; CHECK-64-NEXT: {{70368744177664}}
 ; CHECK-64: ret
 
+; CHECK-AARCH64: @read_4_bytes
+; CHECK-AARCH64-NOT: ret
+; Check for ASAN's Offset for 64-bit (2^47 or 0x800000000000)
+; CHECK-AARCH64: lshr {{.*}} 3
+; CHECK-AARCH64-NEXT: {{140737488355328}}
+; CHECK-AARCH64: ret
+
 ; CHECK-MIPS64: @read_4_bytes
 ; CHECK-MIPS64-NOT: ret
 ; Check for ASAN's Offset for 64-bit (2^37 or 0x2000000000)
 ; CHECK-MIPS64: lshr {{.*}} 3
 ; CHECK-MIPS64-NEXT: {{137438953472}}
 ; CHECK-MIPS64: ret