[LLVM] [AArch64] [DFSan] Adding support of AArch64 for DFSan

[sdkie]

Summary

Added ShadowPtrMask for AArch64 Architecture.

[sdkie]

Considering AArch64 has only 39 bit addressable.

[sdkie]

@kcc @pcc Did you got time to review DFSAN patches for ARM64?

[pcc]

LGTM

[Eugene.Zelenko]

Looks like patch was not committed.

lib/Transforms/Instrumentation/DataFlowSanitizer.cpp

 ///
 /// To derive a shadow memory address from an application memory address,
 /// bits 44-46 are cleared to bring the address into the range
 /// [0x000000008000,0x100000000000).  Then the address is shifted left by 1 to
 /// account for the double byte representation of shadow labels and move the
 /// address into the shadow memory range.  See the function
 /// DataFlowSanitizer::getShadowAddress below.
 ///
+
+/// On Linux/MIPS64, memory is laid out as follows:
+///
+/// +--------------------+ 0x10000000000 (top of memory)
+/// | application memory |
+/// +--------------------+ 0xF000008000 (kAppAddr)
+/// |                    |
+/// |       unused       |
+/// |                    |
+/// +--------------------+ 0x2200000000 (kUnusedAddr)
+/// |    union table     |
+/// +--------------------+ 0x2000000000 (kUnionTableAddr)
+/// |   shadow memory    |
+/// +--------------------+ 0x0000010000 (kShadowAddr)
+/// | reserved by kernel |
+/// +--------------------+ 0x0000000000
+
+/// On Linux/AArch64, memory is laid out as follows:
+///
+/// +--------------------+ 0x8000000000 (top of memory)
+/// | application memory |
+/// +--------------------+ 0x7000008000 (kAppAddr)
+/// |                    |
+/// |       unused       |
+/// |                    |
+/// +--------------------+ 0x2200000000 (kUnusedAddr)
+/// |    union table     |
+/// +--------------------+ 0x2000000000 (kUnionTableAddr)
+/// |   shadow memory    |
+/// +--------------------+ 0x0000010000 (kShadowAddr)
+/// | reserved by kernel |
+/// +--------------------+ 0x0000000000
+
 /// For more information, please refer to the design document:
 /// http://clang.llvm.org/docs/DataFlowSanitizerDesign.html
 
 #include "llvm/Transforms/Instrumentation.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/StringExtras.h"
FunctionType *DataFlowSanitizer::getCustomFunctionType(FunctionType *T) {
   return FunctionType::get(T->getReturnType(), ArgTypes, T->isVarArg());
 }
 
 bool DataFlowSanitizer::doInitialization(Module &M) {
   llvm::Triple TargetTriple(M.getTargetTriple());
   bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
   bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
                   TargetTriple.getArch() == llvm::Triple::mips64el;
+  bool IsAArch64 = TargetTriple.getArch() == llvm::Triple::aarch64;
 
   const DataLayout &DL = M.getDataLayout();
 
   Mod = &M;
   Ctx = &M.getContext();
   ShadowTy = IntegerType::get(*Ctx, ShadowWidth);
   ShadowPtrTy = PointerType::getUnqual(ShadowTy);
   IntptrTy = DL.getIntPtrType(*Ctx);
   ZeroShadow = ConstantInt::getSigned(ShadowTy, 0);
   ShadowPtrMul = ConstantInt::getSigned(IntptrTy, ShadowWidth / 8);
   if (IsX86_64)
     ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0x700000000000LL);
   else if (IsMIPS64)
     ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0xF000000000LL);
+  else if (IsAArch64)
+    ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0x7000000000LL);
   else
     report_fatal_error("unsupported triple");
 
   Type *DFSanUnionArgs[2] = { ShadowTy, ShadowTy };
   DFSanUnionFnTy =
       FunctionType::get(ShadowTy, DFSanUnionArgs, /*isVarArg=*/ false);
   Type *DFSanUnionLoadArgs[2] = { ShadowPtrTy, IntptrTy };
   DFSanUnionLoadFnTy =