fix -fsanitize-address-field-padding for the cases with virtual base classes

[kcc]

Summary

Correctly compute the non-virtual size of a class.

[rsmith]

LGTM

lib/CodeGen/CGClass.cpp

void CodeGenFunction::EmitAsanPrologueOrEpilogue(bool Prologue) {
   llvm::FunctionType *FTy =
       llvm::FunctionType::get(CGM.VoidTy, Args, false);
   llvm::Constant *F = CGM.CreateRuntimeFunction(
       FTy, Prologue ? "__asan_poison_intra_object_redzone"
                     : "__asan_unpoison_intra_object_redzone");
 
   llvm::Value *ThisPtr = LoadCXXThis();
   ThisPtr = Builder.CreatePtrToInt(ThisPtr, IntPtrTy);
-  QualType RecordTy = Context.getTypeDeclType(ClassDecl);
-  uint64_t TypeSize = Context.getTypeSizeInChars(RecordTy).getQuantity();
-
+  uint64_t TypeSize = Info.getNonVirtualSize().getQuantity();
   // For each field check if it has sufficient padding,
   // if so (un)poison it with a call.
   for (size_t i = 0; i < SSV.size(); i++) {
     uint64_t AsanAlignment = 8;
     uint64_t NextField = i == SSV.size() - 1 ? TypeSize : SSV[i + 1].Offset;
     uint64_t PoisonSize = NextField - SSV[i].Offset - SSV[i].Size;
     uint64_t EndOffset = SSV[i].Offset + SSV[i].Size;
     if (PoisonSize < AsanAlignment || !SSV[i].Size ||

test/CodeGen/sanitize-address-field-padding.cpp

private:
   short private_array[6];
   long long private3;
 };
 
 Positive1 positive1;
 // Positive1 with extra paddings
 // CHECK: type { i32, [12 x i8], i8, [15 x i8], i32, [12 x i8], [6 x i16], [12 x i8], i64, [8 x i8] }
 
+struct VirtualBase {
+  int foo;
+};
+
+class ClassWithVirtualBase : public virtual VirtualBase {
+ public:
+  ClassWithVirtualBase() {}
+  ~ClassWithVirtualBase() {}
+  int make_it_non_standard_layout;
+ private:
+  char x[7];
+  char y[9];
+};
+
+ClassWithVirtualBase class_with_virtual_base;
+
+
 class Negative1 {
  public:
   Negative1() {}
   int public1, public2;
 };
 Negative1 negative1;
 // CHECK: type { i32, i32 }
 

 // DTOR
 // CHECK: call void @__asan_unpoison_intra_object_redzone({{.*}}12)
 // CHECK: call void @__asan_unpoison_intra_object_redzone({{.*}}15)
 // CHECK: call void @__asan_unpoison_intra_object_redzone({{.*}}12)
 // CHECK: call void @__asan_unpoison_intra_object_redzone({{.*}}12)
 // CHECK: call void @__asan_unpoison_intra_object_redzone({{.*}}8)
 // CHECK-NOT: __asan_unpoison_intra_object_redzone
 // CHECK: ret void
+//
+//
+// CHECK-LABEL: define linkonce_odr void @_ZN20ClassWithVirtualBaseC1Ev
+// CHECK: call void @__asan_poison_intra_object_redzone({{.*}} 12)
+// CHECK: call void @__asan_poison_intra_object_redzone({{.*}} 9)
+// CHECK: call void @__asan_poison_intra_object_redzone({{.*}} 15)
+// CHECK-NOT: __asan_poison_intra_object_redzone
+// CHECK: ret void
+//