[lldb] Make sure that the "TypeSystemClang::GetBuiltinTypeByName" method returns the correct value also for "_BitInt(...)" types.

[sedymrak]

When trying to get the SBType object corresponding to the _BitInt(...) type name, we have noticed that the SBTarget::FindFirstType metod returns nil. This branch proposes:

• some test that demonstrate that the problem exists
• a possible fix

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Matej Košík (sedymrak)

Changes

When trying to get the SBType object corresponding to the _BitInt(...) type name, we have noticed that the SBTarget::FindFirstType metod returns nil. This branch proposes:

• some test that demonstrate that the problem exists
• a possible fix

---

Full diff: https://github.com/llvm/llvm-project/pull/165857.diff

2 Files Affected:

• (modified) lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp (+11)
• (modified) lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py (+20)

diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index 6ec054d5eac05..cfa936415d634 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -5498,6 +5498,17 @@ TypeSystemClang::GetNumChildren(lldb::opaque_compiler_type_t type,
 }
 
 CompilerType TypeSystemClang::GetBuiltinTypeByName(ConstString name) {
+  StringRef name_ref = name.GetStringRef();
+  llvm::Regex re("^(unsigned )?_BitInt\\((.*)\\)$");
+  llvm::SmallVector<llvm::StringRef, 4> matches;
+  bool is_bitint = re.match(name_ref, &matches);
+  if (is_bitint && matches.size() == 3) {
+    bool is_unsigned = matches[1] == "unsigned ";
+    llvm::APInt ap_bit_size;
+    if (!matches[2].getAsInteger(10, ap_bit_size))
+      return GetType(getASTContext().getBitIntType(is_unsigned,
+                                                   ap_bit_size.getZExtValue()));
+  }
   return GetBasicType(GetBasicTypeEnumeration(name));
 }
 
diff --git a/lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py b/lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py
index f8594dfc6b78d..07a4fae82677d 100644
--- a/lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py
+++ b/lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py
@@ -30,9 +30,29 @@ def test(self):
         self.assertEqual(d.GetType().GetBasicType(), int_basic_type)
 
         # Check the size of the chosen basic types.
+        self.assertEqual(self.target().FindFirstType("__int128").name, "__int128")
         self.assertEqual(self.target().FindFirstType("__int128").size, 16)
+        self.assertEqual(
+            self.target().FindFirstType("unsigned __int128").name, "unsigned __int128"
+        )
         self.assertEqual(self.target().FindFirstType("unsigned __int128").size, 16)
 
         # Check the size of the chosen aliases of basic types.
+        self.assertEqual(self.target().FindFirstType("__int128_t").name, "__int128_t")
         self.assertEqual(self.target().FindFirstType("__int128_t").size, 16)
+        self.assertEqual(self.target().FindFirstType("__uint128_t").name, "__uint128_t")
         self.assertEqual(self.target().FindFirstType("__uint128_t").size, 16)
+
+        # "_BitInt(...)" and "unsigned _BitInt(...)" are GNU C compiler extensions
+        # that are supported by LLVM C(++) compiler as well.
+        #
+        # We check that LLDB is able to map the names of these types
+        # (as reported by LLDB for variables of this type)
+        # to the corresponding SBType objects.
+        self.assertEqual(self.target().FindFirstType("_BitInt(65)").name, "_BitInt(65)")
+        self.assertEqual(self.target().FindFirstType("_BitInt(65)").size, 16)
+        self.assertEqual(
+            self.target().FindFirstType("unsigned _BitInt(65)").name,
+            "unsigned _BitInt(65)",
+        )
+        self.assertEqual(self.target().FindFirstType("unsigned _BitInt(65)").size, 16)