Fix undefined behavior in DWARFASTParser::ParseChildArrayInfo()

PR40827: https://bugs.llvm.org/show_bug.cgi?id=40827
<rdar://problem/48729057>

llvm-svn: 358137

2 files changed, 5 insertions, 3 deletions

diff --git a/lldb/include/lldb/Symbol/SymbolFile.h b/lldb/include/lldb/Symbol/SymbolFile.h
index 5d607989f44..e2f18d81c3e 100644
--- a/lldb/include/lldb/Symbol/SymbolFile.h
+++ b/lldb/include/lldb/Symbol/SymbolFile.h
@@ -132,10 +132,10 @@ public:
 
   /// The characteristics of an array type.
   struct ArrayInfo {
-    int64_t first_index;
+    int64_t first_index = 0;
     llvm::SmallVector<uint64_t, 1> element_orders;
-    uint32_t byte_stride;
-    uint32_t bit_stride;
+    uint32_t byte_stride = 0;
+    uint32_t bit_stride = 0;
   };
   /// If \c type_uid points to an array type, return its characteristics.
   /// To support variable-length array types, this function takes an
diff --git a/lldb/packages/Python/lldbsuite/test/lang/c/array_types/TestArrayTypes.py b/lldb/packages/Python/lldbsuite/test/lang/c/array_types/TestArrayTypes.py
index a47e6c311d4..da3a46ac0bc 100644
--- a/lldb/packages/Python/lldbsuite/test/lang/c/array_types/TestArrayTypes.py
+++ b/lldb/packages/Python/lldbsuite/test/lang/c/array_types/TestArrayTypes.py
@@ -175,6 +175,8 @@ class ArrayTypesTestCase(TestBase):
         self.DebugSBValue(variable)
         self.assertTrue(variable.GetNumChildren() == 4,
                         "Variable 'strings' should have 4 children")
+        byte_size = variable.GetByteSize()
+        self.assertTrue(byte_size >= 4*4 and byte_size <= 1024)
 
         child3 = variable.GetChildAtIndex(3)
         self.DebugSBValue(child3)