[lldb][SBType] GetBasicType to unwrap canonical type (#149112)

`SBType::GetBasicType` fails on typedefs to primitive types. The docs
for `GetBasicType` state:
```
Returns the BasicType value that is most appropriate to this type
```
But, e.g., for `uint64_t` this would currently return
`eBasicTypeInvalid`.

`TypeSystemClang::GetBasicTypeEnumeration` (which is what
`SBType::GetBasicType` uses) doesn't see through typedefs. Inside LLDB
we almost always call `GetBasicTypeEnumeration` on the canonical type.
In the cases we don't I suspect those were just subtle bugs. This patch
gets the canonical type inside of `GetBasicTypeEnumeration` instead.

rdar://155829208

3 files changed, 44 insertions, 0 deletions

diff --git a/lldb/test/API/python_api/sbtype_basic_type/Makefile b/lldb/test/API/python_api/sbtype_basic_type/Makefile
new file mode 100644
index 0000000..99998b2
--- /dev/null
+++ b/lldb/test/API/python_api/sbtype_basic_type/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules
diff --git a/lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py b/lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py
new file mode 100644
index 0000000..535d8b9
--- /dev/null
+++ b/lldb/test/API/python_api/sbtype_basic_type/TestSBTypeBasicType.py
@@ -0,0 +1,30 @@
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestCase(TestBase):
+    def test(self):
+        """Test that SBType.GetBasicType unwraps typedefs."""
+        self.build()
+        lldbutil.run_to_source_breakpoint(self, "return", lldb.SBFileSpec("main.cpp"))
+
+        a = self.frame().FindVariable("a")
+        self.assertTrue(a)
+
+        int_basic_type = a.GetType().GetBasicType()
+        self.assertEqual(int_basic_type, 13)
+
+        b = self.frame().FindVariable("b")
+        self.assertTrue(b)
+
+        c = self.frame().FindVariable("c")
+        self.assertTrue(c)
+
+        d = self.frame().FindVariable("d")
+        self.assertTrue(d)
+
+        self.assertEqual(b.GetType().GetBasicType(), int_basic_type)
+        self.assertEqual(c.GetType().GetBasicType(), int_basic_type)
+        self.assertEqual(d.GetType().GetBasicType(), int_basic_type)
diff --git a/lldb/test/API/python_api/sbtype_basic_type/main.cpp b/lldb/test/API/python_api/sbtype_basic_type/main.cpp
new file mode 100644
index 0000000..7ded371
--- /dev/null
+++ b/lldb/test/API/python_api/sbtype_basic_type/main.cpp
@@ -0,0 +1,11 @@
+using T1 = int;
+using T2 = T1;
+using T3 = T2;
+
+int main() {
+  int a;
+  T1 b;
+  T2 c;
+  T3 d;
+  return 0;
+}