[RISCV][ASAN] instrumentation pass now uses proper shadow offset

[EccoTheDolphin]

Summary

[10/11] patch series to port ASAN for riscv64

Depends On D87580

[eugenis]

LGTM

[EccoTheDolphin]

rebasing

[EccoTheDolphin]

rebasing

[EccoTheDolphin]

rebasing

[EccoTheDolphin]

[NFC] formatting: kRiscv64_ShadowOffset64->kRISCV64_ShadowOffset64

[EccoTheDolphin]

Regarding the build failure (linux > libarcher.parallel::parallel-nosuppression.c). I assume that my change is not related to this failure:

1. This is a completely different codebase.
2. I observe this failure on other revisions too, for example: https://reviews.llvm.org/D88580

As such I take the liberty to commit the change since it was accepted and is quite simple.

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

 static const uint64_t kSmallX86_64ShadowOffsetBase = 0x7FFFFFFF;  // < 2G.
 static const uint64_t kSmallX86_64ShadowOffsetAlignMask = ~0xFFFULL;
 static const uint64_t kLinuxKasan_ShadowOffset64 = 0xdffffc0000000000;
 static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 44;
 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 kRiscv64_ShadowOffset64 = 0x20000000;
 static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
 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 kPS4CPU_ShadowOffset64 = 1ULL << 40;
 static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
 static const uint64_t kEmscriptenShadowOffset = 0;
static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
   bool IsPPC64 = TargetTriple.getArch() == Triple::ppc64 ||
                  TargetTriple.getArch() == Triple::ppc64le;
   bool IsSystemZ = TargetTriple.getArch() == Triple::systemz;
   bool IsX86_64 = TargetTriple.getArch() == Triple::x86_64;
   bool IsMIPS32 = TargetTriple.isMIPS32();
   bool IsMIPS64 = TargetTriple.isMIPS64();
   bool IsArmOrThumb = TargetTriple.isARM() || TargetTriple.isThumb();
   bool IsAArch64 = TargetTriple.getArch() == Triple::aarch64;
+  bool IsRISCV64 = TargetTriple.getArch() == Triple::riscv64;
   bool IsWindows = TargetTriple.isOSWindows();
   bool IsFuchsia = TargetTriple.isOSFuchsia();
   bool IsMyriad = TargetTriple.getVendor() == llvm::Triple::Myriad;
   bool IsEmscripten = TargetTriple.isOSEmscripten();
 
   ShadowMapping Mapping;
 
   Mapping.Scale = IsMyriad ? kMyriadShadowScale : kDefaultShadowScale;
if (LongSize == 32) {
     } 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 if (IsRISCV64)
+      Mapping.Offset = kRiscv64_ShadowOffset64;
     else
       Mapping.Offset = kDefaultShadowOffset64;
   }
 
   if (ClForceDynamicShadow) {
     Mapping.Offset = kDynamicShadowSentinel;
   }
 
   if (ClMappingOffset.getNumOccurrences() > 0) {
     Mapping.Offset = ClMappingOffset;
   }
 
   // OR-ing shadow offset if more efficient (at least on x86) if the offset
   // is a power of two, but on ppc64 we have to use add since the shadow
   // offset is not necessary 1/8-th of the address space.  On SystemZ,
   // we could OR the constant in a single instruction, but it's more
   // efficient to load it once and use indexed addressing.
   Mapping.OrShadowOffset = !IsAArch64 && !IsPPC64 && !IsSystemZ && !IsPS4CPU &&
+                           !IsRISCV64 &&
                            !(Mapping.Offset & (Mapping.Offset - 1)) &&
                            Mapping.Offset != kDynamicShadowSentinel;
   bool IsAndroidWithIfuncSupport =
       IsAndroid && !TargetTriple.isAndroidVersionLT(21);
   Mapping.InGlobal = ClWithIfunc && IsAndroidWithIfuncSupport && IsArmOrThumb;
 
   return Mapping;
 }