Add the llvm asan support

[andrew]

Summary

Add the llvm support for running AddressSanitizer on FreeBSD on AArch64. The address space is larger on FreeBSD/arm64, create a new constant for this.

[andrew]

The compiler-rt bits are in D32172

[andrew]

Is there any feedback on this?

[peter.smith]

I think you probably have the wrong set of reviewers. From a pure change perspective it looks fine to me, however I think you'll need to check with someone who knows the details of BSD and someone in the ASAN team to check it over stylistically. Perhaps Ed Maste on the BSD side and I think Kosta Serebryany on the sanitizer side. The same comment applies to D32172 . Apologies I don't feel like I can offer much help in reviewing.

[emaste]

The change looks fine to me from a FreeBSD perspective

lib/Transforms/Instrumentation/AddressSanitizer.cpp

 static const uint64_t kLinuxKasan_ShadowOffset64 = 0xdffffc0000000000;
 static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
 static const uint64_t kSystemZ_ShadowOffset64 = 1ULL << 52;
 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 kFreeBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
+static const uint64_t kFreeBSD_AArch64_ShadowOffset64 = 1ULL << 47;
 static const uint64_t kPS4CPU_ShadowOffset64 = 1ULL << 40;
 static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
 // The shadow memory space is dynamically allocated.
 static const uint64_t kWindowsShadowOffset64 = kDynamicShadowSentinel;
 
 static const size_t kMinStackMallocSize = 1 << 6;   // 64B
 static const size_t kMaxStackMallocSize = 1 << 16;  // 64K
 static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
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 = kFreeBSD_AArch64_ShadowOffset64;
     else if (IsFreeBSD)
       Mapping.Offset = kFreeBSD_ShadowOffset64;
     else if (IsPS4CPU)
       Mapping.Offset = kPS4CPU_ShadowOffset64;
     else if (IsLinux && IsX86_64) {
       if (IsKasan)
         Mapping.Offset = kLinuxKasan_ShadowOffset64;
       else

test/Instrumentation/AddressSanitizer/freebsd.ll

 ; RUN: opt < %s -asan -asan-module -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 -asan -asan-module -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 -asan -asan-module -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
+
 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