[llvm] r320572 - [FuzzMutate] Avoid zero sized aggregates

[Igor Laevsky via llvm-commits]

Author: igor.laevsky
Date: Wed Dec 13 03:47:35 2017
New Revision: 320572

URL: http://llvm.org/viewvc/llvm-project?rev=320572&view=rev
Log:
[FuzzMutate] Avoid zero sized aggregates

Differential Revision: https://reviews.llvm.org/D41110


Modified:
    llvm/trunk/include/llvm/FuzzMutate/OpDescriptor.h
    llvm/trunk/unittests/FuzzMutate/OperationsTest.cpp

Modified: llvm/trunk/include/llvm/FuzzMutate/OpDescriptor.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/FuzzMutate/OpDescriptor.h?rev=320572&r1=320571&r2=320572&view=diff
==============================================================================
--- llvm/trunk/include/llvm/FuzzMutate/OpDescriptor.h (original)
+++ llvm/trunk/include/llvm/FuzzMutate/OpDescriptor.h Wed Dec 13 03:47:35 2017
@@ -160,6 +160,14 @@ static inline SourcePred sizedPtrType()
 
 static inline SourcePred anyAggregateType() {
   auto Pred = [](ArrayRef<Value *>, const Value *V) {
+    // We can't index zero sized arrays.
+    if (isa<ArrayType>(V->getType()))
+      return V->getType()->getArrayNumElements() > 0;
+
+    // Structs can also be zero sized. I.e opaque types.
+    if (isa<StructType>(V->getType()))
+      return V->getType()->getStructNumElements() > 0;
+
     return V->getType()->isAggregateType();
   };
   // TODO: For now we only find aggregates in BaseTypes. It might be better to

Modified: llvm/trunk/unittests/FuzzMutate/OperationsTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/FuzzMutate/OperationsTest.cpp?rev=320572&r1=320571&r2=320572&view=diff
==============================================================================
--- llvm/trunk/unittests/FuzzMutate/OperationsTest.cpp (original)
+++ llvm/trunk/unittests/FuzzMutate/OperationsTest.cpp Wed Dec 13 03:47:35 2017
@@ -336,6 +336,7 @@ TEST(OperationsTest, ExtractAndInsertVal
 
   Type *StructTy = StructType::create(Ctx, {Int8PtrTy, Int32Ty});
   Type *OpaqueTy = StructType::create(Ctx, "OpaqueStruct");
+  Type *ZeroSizedArrayTy = ArrayType::get(Int64Ty, 0);
   Type *ArrayTy = ArrayType::get(Int64Ty, 4);
   Type *VectorTy = VectorType::get(Int32Ty, 2);
 
@@ -346,17 +347,22 @@ TEST(OperationsTest, ExtractAndInsertVal
   Constant *SVal = UndefValue::get(StructTy);
   Constant *OVal = UndefValue::get(OpaqueTy);
   Constant *AVal = UndefValue::get(ArrayTy);
+  Constant *ZAVal = UndefValue::get(ZeroSizedArrayTy);
   Constant *VVal = UndefValue::get(VectorTy);
 
   EXPECT_TRUE(EVOp.SourcePreds[0].matches({}, SVal));
-  EXPECT_TRUE(EVOp.SourcePreds[0].matches({}, OVal));
+  EXPECT_FALSE(EVOp.SourcePreds[0].matches({}, OVal));
   EXPECT_TRUE(EVOp.SourcePreds[0].matches({}, AVal));
   EXPECT_FALSE(EVOp.SourcePreds[0].matches({}, VVal));
   EXPECT_TRUE(IVOp.SourcePreds[0].matches({}, SVal));
-  EXPECT_TRUE(IVOp.SourcePreds[0].matches({}, OVal));
+  EXPECT_FALSE(IVOp.SourcePreds[0].matches({}, OVal));
   EXPECT_TRUE(IVOp.SourcePreds[0].matches({}, AVal));
   EXPECT_FALSE(IVOp.SourcePreds[0].matches({}, VVal));
 
+  // Don't consider zero sized arrays as viable sources
+  EXPECT_FALSE(EVOp.SourcePreds[0].matches({}, ZAVal));
+  EXPECT_FALSE(IVOp.SourcePreds[0].matches({}, ZAVal));
+
   // Make sure we're range checking appropriately.
   EXPECT_TRUE(
       EVOp.SourcePreds[1].matches({SVal}, ConstantInt::get(Int32Ty, 0)));