[ASan][compiler-rt] Implemented Dormant Mode in ASan

compiler-rt/include/sanitizer/asan_interface.h

@@ -269,6 +269,13 @@ void SANITIZER_CDECL __asan_set_death_callback(void (*callback)(void));
 void SANITIZER_CDECL
 __asan_set_error_report_callback(void (*callback)(const char *));
 
+/// Sets whether ASan should be dormant or not. If 0 is passed, ASan resumes
+/// checking memory accesses for errors. If a non-0 value is passed, these
+/// checks will be skipped.
+///
+/// \param dormancy A boolean to control if ASan is dormant or not.
+void SANITIZER_CDECL __asan_set_dormant(int dormancy);
+
 /// User-provided callback on ASan errors.
 ///
 /// You can provide a function that would be called immediately when ASan

compiler-rt/lib/asan/asan_interface.inc

@@ -107,6 +107,7 @@ INTERFACE_FUNCTION(__asan_report_store16_noabort)
 INTERFACE_FUNCTION(__asan_report_store_n_noabort)
 INTERFACE_FUNCTION(__asan_set_death_callback)
 INTERFACE_FUNCTION(__asan_set_error_report_callback)
+INTERFACE_FUNCTION(__asan_set_dormant)
 INTERFACE_FUNCTION(__asan_set_shadow_00)
 INTERFACE_FUNCTION(__asan_set_shadow_01)
 INTERFACE_FUNCTION(__asan_set_shadow_02)

compiler-rt/lib/asan/asan_interface_internal.h

@@ -184,6 +184,9 @@ extern "C" {
   SANITIZER_INTERFACE_ATTRIBUTE
   void __asan_set_error_report_callback(void (*callback)(const char*));
 
+  SANITIZER_INTERFACE_ATTRIBUTE
+  void __asan_set_dormant(int dormancy);
+
   SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
   void __asan_on_error();
 
@@ -202,6 +205,9 @@ extern "C" {
   SANITIZER_INTERFACE_ATTRIBUTE
   extern uptr *__asan_test_only_reported_buggy_pointer;
 
+  SANITIZER_INTERFACE_ATTRIBUTE
+  extern int __asan_is_dormant;
+
   SANITIZER_INTERFACE_ATTRIBUTE void __asan_load1(uptr p);
   SANITIZER_INTERFACE_ATTRIBUTE void __asan_load2(uptr p);
   SANITIZER_INTERFACE_ATTRIBUTE void __asan_load4(uptr p);

compiler-rt/lib/asan/asan_rtl.cpp

@@ -36,6 +36,9 @@
 uptr __asan_shadow_memory_dynamic_address;  // Global interface symbol.
 int __asan_option_detect_stack_use_after_return;  // Global interface symbol.
 uptr *__asan_test_only_reported_buggy_pointer;  // Used only for testing asan.
+int __asan_is_dormant = true;  // Used only if compiling with dormant asan
+
+void __asan_set_dormant(int dormancy) { __asan_is_dormant = dormancy; }
 
 namespace __asan {
 

compiler-rt/test/asan/TestCases/dormant.cpp

@@ -0,0 +1,37 @@
+// RUN: %clangxx_asan -DREAD -O0 -mllvm -asan-dormant %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-READ
+// RUN: %clangxx_asan -O0 -mllvm -asan-dormant %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-WRITE
+// REQUIRES: stable-runtime
+
+#include <sanitizer/asan_interface.h>
+int readHeapAfterFree(){
+  int * volatile x = new int[10];
+  delete[] x;
+  return x[5];
+}
+
+static int * volatile y;
+int writeHeapAfterFree(){
+  y = new int[10];
+  delete[] y;
+  return y[5] = 413;
+}
+
+int main() {
+#ifdef READ
+  readHeapAfterFree();
+  // CHECK-READCHECK-NOT {{.*ERROR: AddressSanitizer: heap-use-after-free on address}}
+  __asan_set_dormant(false);
+  readHeapAfterFree();
+  // CHECK-READ: {{.*ERROR: AddressSanitizer: heap-use-after-free on address}}
+
+#else
+
+  writeHeapAfterFree();
+  // CHECK-WRITE-NOT {{.*ERROR: AddressSanitizer: heap-use-after-free on address}}
+  __asan_set_dormant(false);
+  writeHeapAfterFree();
+  // CHECK-WRITE: {{.*ERROR: AddressSanitizer: heap-use-after-free on address}}
+#endif
+
+  return 0;
+}

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -178,6 +178,8 @@ const char kAMDGPUAddressPrivateName[] = "llvm.amdgcn.is.private";
 const char kAMDGPUBallotName[] = "llvm.amdgcn.ballot.i64";
 const char kAMDGPUUnreachableName[] = "llvm.amdgcn.unreachable";
 
+const char kAsanDormancyVarName[] = "__asan_is_dormant";
+
 // Accesses sizes are powers of two: 1, 2, 4, 8, 16.
 static const size_t kNumberOfAccessSizes = 5;
 
@@ -452,6 +454,10 @@ static cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"),
 static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug max inst"),
                                cl::Hidden, cl::init(-1));
 
+static cl::opt<bool> ClAsanDormant("asan-dormant",
+                                   cl::desc("Makes asan dormant"), cl::Hidden,
+                                   cl::init(false));
+
 STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
 STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
 STATISTIC(NumOptimizedAccessesToGlobalVar,
@@ -852,6 +858,7 @@ struct AddressSanitizer {
 
   FunctionCallee AsanMemmove, AsanMemcpy, AsanMemset;
   Value *LocalDynamicShadow = nullptr;
+  Constant *DormantAsanFlag;
   const StackSafetyGlobalInfo *SSGI;
   DenseMap<const AllocaInst *, bool> ProcessedAllocas;
 
@@ -1584,6 +1591,12 @@ bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) {
 void AddressSanitizer::instrumentPointerComparisonOrSubtraction(
     Instruction *I, RuntimeCallInserter &RTCI) {
   IRBuilder<> IRB(I);
+
+  if (ClAsanDormant)
+    IRB.SetInsertPoint(SplitBlockAndInsertIfThen(
+        IRB.CreateNot(IRB.CreateLoad(IRB.getInt1Ty(), DormantAsanFlag)), I,
+        false, MDBuilder(*C).createUnlikelyBranchWeights()));
+
   FunctionCallee F = isa<ICmpInst>(I) ? AsanPtrCmpFunction : AsanPtrSubFunction;
   Value *Param[2] = {I->getOperand(0), I->getOperand(1)};
   for (Value *&i : Param) {
@@ -1729,15 +1742,23 @@ void AddressSanitizer::instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis,
     NumInstrumentedWrites++;
   else
     NumInstrumentedReads++;
+
+  Instruction* InsertPoint = O.getInsn();
+  if(ClAsanDormant){
+    InstrumentationIRBuilder IRB(InsertPoint);
+    InsertPoint = SplitBlockAndInsertIfThen(
+        IRB.CreateNot(IRB.CreateLoad(IRB.getInt1Ty(), DormantAsanFlag)),
+        InsertPoint, false, MDBuilder(*C).createUnlikelyBranchWeights());
+  }
 
   unsigned Granularity = 1 << Mapping.Scale;
   if (O.MaybeMask) {
     instrumentMaskedLoadOrStore(this, DL, IntptrTy, O.MaybeMask, O.MaybeEVL,
-                                O.MaybeStride, O.getInsn(), Addr, O.Alignment,
+                                O.MaybeStride, InsertPoint, Addr, O.Alignment,
                                 Granularity, O.OpType, O.IsWrite, nullptr,
                                 UseCalls, Exp, RTCI);
   } else {
-    doInstrumentAddress(this, O.getInsn(), O.getInsn(), Addr, O.Alignment,
+    doInstrumentAddress(this, InsertPoint, InsertPoint, Addr, O.Alignment,
                         Granularity, O.TypeStoreSize, O.IsWrite, nullptr,
                         UseCalls, Exp, RTCI);
   }
@@ -2860,6 +2881,8 @@ void AddressSanitizer::initializeCallbacks(Module &M, const TargetLibraryInfo *T
       M.getOrInsertFunction(kAMDGPUAddressSharedName, IRB.getInt1Ty(), PtrTy);
   AMDGPUAddressPrivate =
       M.getOrInsertFunction(kAMDGPUAddressPrivateName, IRB.getInt1Ty(), PtrTy);
+
+  DormantAsanFlag = M.getOrInsertGlobal(kAsanDormancyVarName, IRB.getInt1Ty());
 }
 
 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {

llvm/test/Instrumentation/AddressSanitizer/dormant.ll

@@ -0,0 +1,88 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes=asan -asan-dormant -S | FileCheck --check-prefixes=CHECK %s
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: mustprogress noinline nounwind optnone uwtable
+define dso_local i32 @test(ptr %a) sanitize_address {
+; CHECK-LABEL: define dso_local i32 @test(
+; CHECK-SAME: ptr [[A:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[A_ADDR:%.*]] = alloca ptr, align 8
+; CHECK-NEXT:    store ptr [[A]], ptr [[A_ADDR]], align 8
+; CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[A_ADDR]], align 8
+; CHECK-NEXT:    [[TMP1:%.*]] = load i1, ptr @__asan_is_dormant, align 1
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i1 [[TMP1]], true
+; CHECK-NEXT:    br i1 [[TMP2]], label %[[BB3:.*]], label %[[BB17:.*]], !prof [[PROF7:![0-9]+]]
+; CHECK:       [[BB3]]:
+; CHECK-NEXT:    [[TMP4:%.*]] = ptrtoint ptr [[TMP0]] to i64
+; CHECK-NEXT:    [[TMP5:%.*]] = lshr i64 [[TMP4]], 3
+; CHECK-NEXT:    [[TMP6:%.*]] = add i64 [[TMP5]], 2147450880
+; CHECK-NEXT:    [[TMP7:%.*]] = inttoptr i64 [[TMP6]] to ptr
+; CHECK-NEXT:    [[TMP8:%.*]] = load i8, ptr [[TMP7]], align 1
+; CHECK-NEXT:    [[TMP9:%.*]] = icmp ne i8 [[TMP8]], 0
+; CHECK-NEXT:    br i1 [[TMP9]], label %[[BB10:.*]], label %[[BB16:.*]], !prof [[PROF7]]
+; CHECK:       [[BB10]]:
+; CHECK-NEXT:    [[TMP11:%.*]] = and i64 [[TMP4]], 7
+; CHECK-NEXT:    [[TMP12:%.*]] = add i64 [[TMP11]], 3
+; CHECK-NEXT:    [[TMP13:%.*]] = trunc i64 [[TMP12]] to i8
+; CHECK-NEXT:    [[TMP14:%.*]] = icmp sge i8 [[TMP13]], [[TMP8]]
+; CHECK-NEXT:    br i1 [[TMP14]], label %[[BB15:.*]], label %[[BB16]]
+; CHECK:       [[BB15]]:
+; CHECK-NEXT:    call void @__asan_report_store4(i64 [[TMP4]]) #[[ATTR3:[0-9]+]]
+; CHECK-NEXT:    unreachable
+; CHECK:       [[BB16]]:
+; CHECK-NEXT:    br label %[[BB17]]
+; CHECK:       [[BB17]]:
+; CHECK-NEXT:    store i32 5, ptr [[TMP0]], align 4
+; CHECK-NEXT:    [[TMP18:%.*]] = load ptr, ptr [[A_ADDR]], align 8
+; CHECK-NEXT:    [[TMP19:%.*]] = load i1, ptr @__asan_is_dormant, align 1
+; CHECK-NEXT:    [[TMP20:%.*]] = xor i1 [[TMP19]], true
+; CHECK-NEXT:    br i1 [[TMP20]], label %[[BB21:.*]], label %[[BB35:.*]], !prof [[PROF7]]
+; CHECK:       [[BB21]]:
+; CHECK-NEXT:    [[TMP22:%.*]] = ptrtoint ptr [[TMP18]] to i64
+; CHECK-NEXT:    [[TMP23:%.*]] = lshr i64 [[TMP22]], 3
+; CHECK-NEXT:    [[TMP24:%.*]] = add i64 [[TMP23]], 2147450880
+; CHECK-NEXT:    [[TMP25:%.*]] = inttoptr i64 [[TMP24]] to ptr
+; CHECK-NEXT:    [[TMP26:%.*]] = load i8, ptr [[TMP25]], align 1
+; CHECK-NEXT:    [[TMP27:%.*]] = icmp ne i8 [[TMP26]], 0
+; CHECK-NEXT:    br i1 [[TMP27]], label %[[BB28:.*]], label %[[BB34:.*]], !prof [[PROF7]]
+; CHECK:       [[BB28]]:
+; CHECK-NEXT:    [[TMP29:%.*]] = and i64 [[TMP22]], 7
+; CHECK-NEXT:    [[TMP30:%.*]] = add i64 [[TMP29]], 3
+; CHECK-NEXT:    [[TMP31:%.*]] = trunc i64 [[TMP30]] to i8
+; CHECK-NEXT:    [[TMP32:%.*]] = icmp sge i8 [[TMP31]], [[TMP26]]
+; CHECK-NEXT:    br i1 [[TMP32]], label %[[BB33:.*]], label %[[BB34]]
+; CHECK:       [[BB33]]:
+; CHECK-NEXT:    call void @__asan_report_load4(i64 [[TMP22]]) #[[ATTR3]]
+; CHECK-NEXT:    unreachable
+; CHECK:       [[BB34]]:
+; CHECK-NEXT:    br label %[[BB35]]
+; CHECK:       [[BB35]]:
+; CHECK-NEXT:    [[TMP36:%.*]] = load i32, ptr [[TMP18]], align 4
+; CHECK-NEXT:    ret i32 [[TMP36]]
+;
+entry:
+  %a.addr = alloca ptr, align 8
+  store ptr %a, ptr %a.addr, align 8
+  %0 = load ptr, ptr %a.addr, align 8
+  store i32 5, ptr %0, align 4
+  %1 = load ptr, ptr %a.addr, align 8
+  %2 = load i32, ptr %1, align 4
+  ret i32 %2
+
+}
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4}
+!llvm.ident = !{!5}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 8, !"PIC Level", i32 2}
+!2 = !{i32 7, !"PIE Level", i32 2}
+!3 = !{i32 7, !"uwtable", i32 2}
+!4 = !{i32 7, !"frame-pointer", i32 2}
+!5 = !{!"clang version 20.0.0git (https://github.com/gbMattN/llvm-project.git 3d0736cd0a60f7f0f78a14982091e5687e2be7da)"}
+;.
+; CHECK: [[PROF7]] = !{!"branch_weights", i32 1, i32 1048575}
+;.