[lldb] Encode `bool` as unsigned int

`bool` is considered to be unsigned according to `std::is_unsigned<bool>::value` (and `Type::GetTypeInfo`). Encoding it as signed int works fine for normal variables and fields, but breaks when reading the values of boolean bitfields. If the field is declared as `bool b : 1` and has a value of `0b1`, the call to `SBValue::GetValueAsSigned()` will return `-1`.

Reviewed By: teemperor

Differential Revision: https://reviews.llvm.org/D102685

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

@@ -4698,7 +4698,6 @@ lldb::Encoding TypeSystemClang::GetEncoding(lldb::opaque_compiler_type_t type,
     case clang::BuiltinType::Void:
       break;
 
-    case clang::BuiltinType::Bool:
     case clang::BuiltinType::Char_S:
     case clang::BuiltinType::SChar:
     case clang::BuiltinType::WChar_S:
@@ -4709,6 +4708,7 @@ lldb::Encoding TypeSystemClang::GetEncoding(lldb::opaque_compiler_type_t type,
     case clang::BuiltinType::Int128:
       return lldb::eEncodingSint;
 
+    case clang::BuiltinType::Bool:
     case clang::BuiltinType::Char_U:
     case clang::BuiltinType::UChar:
     case clang::BuiltinType::WChar_U:

lldb/test/API/lang/cpp/bitfields/TestCppBitfields.py

@@ -120,3 +120,36 @@ class CppBitfieldsTestCase(TestBase):
                 '(uint32_t) b_a = 2',
                 '(uint32_t:1) d_a = 1',
                 ])
+
+        self.expect(
+            "frame variable --show-types bb",
+            VARIABLES_DISPLAYED_CORRECTLY,
+            substrs=[
+                '(bool:1) a = true',
+                '(bool:1) b = false',
+                '(bool:2) c = true',
+                '(bool:2) d = true',
+                ])
+
+        bb = self.frame().FindVariable('bb')
+        self.assertTrue(bb.IsValid())
+
+        bb_a = bb.GetChildAtIndex(0)
+        self.assertTrue(bb_a.IsValid())
+        self.assertEqual(bb_a.GetValueAsUnsigned(), 1)
+        self.assertEqual(bb_a.GetValueAsSigned(), 1)
+
+        bb_b = bb.GetChildAtIndex(1)
+        self.assertTrue(bb_b.IsValid())
+        self.assertEqual(bb_b.GetValueAsUnsigned(), 0)
+        self.assertEqual(bb_b.GetValueAsSigned(), 0)
+
+        bb_c = bb.GetChildAtIndex(2)
+        self.assertTrue(bb_c.IsValid())
+        self.assertEqual(bb_c.GetValueAsUnsigned(), 1)
+        self.assertEqual(bb_c.GetValueAsSigned(), 1)
+
+        bb_d = bb.GetChildAtIndex(3)
+        self.assertTrue(bb_d.IsValid())
+        self.assertEqual(bb_d.GetValueAsUnsigned(), 1)
+        self.assertEqual(bb_d.GetValueAsSigned(), 1)

lldb/test/API/lang/cpp/bitfields/main.cpp

@@ -104,5 +104,17 @@ int main(int argc, char const *argv[]) {
   uwbf.x = 0xFFFFFFFF;
   uwubf.x = 0xFFFFFFFF;
 
+  struct BoolBits {
+    bool a : 1;
+    bool b : 1;
+    bool c : 2;
+    bool d : 2;
+  } bb;
+
+  bb.a = 0b1;
+  bb.b = 0b0;
+  bb.c = 0b11;
+  bb.d = 0b01;
+
   return 0; // Set break point at this line.
 }