revert 281908 because 281909 got reverted

llvm-svn: 282097

1 files changed, 7 insertions, 46 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index c5bcb39992f..992920ff1e5 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -67,7 +67,6 @@ using namespace llvm;
 static const uint64_t kDefaultShadowScale = 3;
 static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
 static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
-static const uint64_t kDynamicShadowSentinel = ~(uint64_t)0;
 static const uint64_t kIOSShadowOffset32 = 1ULL << 30;
 static const uint64_t kIOSShadowOffset64 = 0x120200000;
 static const uint64_t kIOSSimShadowOffset32 = 1ULL << 30;
@@ -82,8 +81,8 @@ 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 kWindowsShadowOffset32 = 3ULL << 28;
-// The shadow memory space is dynamically allocated.
-static const uint64_t kWindowsShadowOffset64 = kDynamicShadowSentinel;
+// TODO(wwchrome): Experimental for asan Win64, may change.
+static const uint64_t kWindowsShadowOffset64 = 0x1ULL << 45;  // 32TB.
 
 static const size_t kMinStackMallocSize = 1 << 6;   // 64B
 static const size_t kMaxStackMallocSize = 1 << 16;  // 64K
@@ -126,9 +125,6 @@ static const char *const kAsanGlobalsRegisteredFlagName =
 static const char *const kAsanOptionDetectUseAfterReturn =
     "__asan_option_detect_stack_use_after_return";
 
-static const char *const kAsanShadowMemoryDynamicAddress =
-    "__asan_shadow_memory_dynamic_address";
-
 static const char *const kAsanAllocaPoison = "__asan_alloca_poison";
 static const char *const kAsanAllocasUnpoison = "__asan_allocas_unpoison";
 
@@ -161,11 +157,6 @@ static cl::opt<bool> ClAlwaysSlowPath(
     "asan-always-slow-path",
     cl::desc("use instrumentation with slow path for all accesses"), cl::Hidden,
     cl::init(false));
-static cl::opt<bool> ClForceDynamicShadow(
-    "asan-force-dynamic-shadow",
-    cl::desc("Load shadow address into a local variable for each function"),
-    cl::Hidden, cl::init(false));
-
 // This flag limits the number of instructions to be instrumented
 // in any given BB. Normally, this should be set to unlimited (INT_MAX),
 // but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
@@ -456,8 +447,7 @@ static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
   // 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
-                           && !(Mapping.Offset & (Mapping.Offset - 1))
-                           && Mapping.Offset != kDynamicShadowSentinel;
+                           && !(Mapping.Offset & (Mapping.Offset - 1));
 
   return Mapping;
 }
@@ -474,8 +464,7 @@ struct AddressSanitizer : public FunctionPass {
                             bool UseAfterScope = false)
       : FunctionPass(ID), CompileKernel(CompileKernel || ClEnableKasan),
         Recover(Recover || ClRecover),
-        UseAfterScope(UseAfterScope || ClUseAfterScope),
-        LocalDynamicShadow(nullptr) {
+        UseAfterScope(UseAfterScope || ClUseAfterScope) {
     initializeAddressSanitizerPass(*PassRegistry::getPassRegistry());
   }
   const char *getPassName() const override {
@@ -523,7 +512,6 @@ struct AddressSanitizer : public FunctionPass {
   Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
   bool runOnFunction(Function &F) override;
   bool maybeInsertAsanInitAtFunctionEntry(Function &F);
-  void maybeInsertDynamicShadowAtFunctionEntry(Function &F);
   void markEscapedLocalAllocas(Function &F);
   bool doInitialization(Module &M) override;
   bool doFinalization(Module &M) override;
@@ -545,12 +533,8 @@ struct AddressSanitizer : public FunctionPass {
     FunctionStateRAII(AddressSanitizer *Pass) : Pass(Pass) {
       assert(Pass->ProcessedAllocas.empty() &&
              "last pass forgot to clear cache");
-      assert(!Pass->LocalDynamicShadow);
-    }
-    ~FunctionStateRAII() {
-      Pass->LocalDynamicShadow = nullptr;
-      Pass->ProcessedAllocas.clear();
     }
+    ~FunctionStateRAII() { Pass->ProcessedAllocas.clear(); }
   };
 
   LLVMContext *C;
@@ -574,7 +558,6 @@ struct AddressSanitizer : public FunctionPass {
   Function *AsanMemoryAccessCallbackSized[2][2];
   Function *AsanMemmove, *AsanMemcpy, *AsanMemset;
   InlineAsm *EmptyAsm;
-  Value *LocalDynamicShadow;
   GlobalsMetadata GlobalsMD;
   DenseMap<const AllocaInst *, bool> ProcessedAllocas;
 
@@ -938,15 +921,10 @@ Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
   Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
   if (Mapping.Offset == 0) return Shadow;
   // (Shadow >> scale) | offset
-  Value *ShadowBase;
-  if (LocalDynamicShadow)
-    ShadowBase = LocalDynamicShadow;
-  else
-    ShadowBase = ConstantInt::get(IntptrTy, Mapping.Offset);
   if (Mapping.OrShadowOffset)
-    return IRB.CreateOr(Shadow, ShadowBase);
+    return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
   else
-    return IRB.CreateAdd(Shadow, ShadowBase);
+    return IRB.CreateAdd(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
 }
 
 // Instrument memset/memmove/memcpy
@@ -999,10 +977,6 @@ Value *AddressSanitizer::isInterestingMemoryAccess(Instruction *I,
   // Skip memory accesses inserted by another instrumentation.
   if (I->getMetadata("nosanitize")) return nullptr;
 
-  // Do not instrument the load fetching the dynamic shadow address.
-  if (LocalDynamicShadow == I)
-    return nullptr;
-
   Value *PtrOperand = nullptr;
   const DataLayout &DL = I->getModule()->getDataLayout();
   if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
@@ -1807,17 +1781,6 @@ bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
   return false;
 }
 
-void AddressSanitizer::maybeInsertDynamicShadowAtFunctionEntry(Function &F) {
-  // Generate code only when dynamic addressing is needed.
-  if (!ClForceDynamicShadow && Mapping.Offset != kDynamicShadowSentinel)
-    return;
-
-  IRBuilder<> IRB(&F.front().front());
-  Value *GlobalDynamicAddress = F.getParent()->getOrInsertGlobal(
-      kAsanShadowMemoryDynamicAddress, IntptrTy);
-  LocalDynamicShadow = IRB.CreateLoad(GlobalDynamicAddress);
-}
-
 void AddressSanitizer::markEscapedLocalAllocas(Function &F) {
   // Find the one possible call to llvm.localescape and pre-mark allocas passed
   // to it as uninteresting. This assumes we haven't started processing allocas
@@ -1870,8 +1833,6 @@ bool AddressSanitizer::runOnFunction(Function &F) {
 
   FunctionStateRAII CleanupObj(this);
 
-  maybeInsertDynamicShadowAtFunctionEntry(F);
-
   // We can't instrument allocas used with llvm.localescape. Only static allocas
   // can be passed to that intrinsic.
   markEscapedLocalAllocas(F);