[Lldb-commits] [lldb] [lldb][TypeSystemClang] Added unique builtins types for __bf16 and _Float16 (PR #157674)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: None (tgs-sc)

<details>
<summary>Changes</summary>

During debugging applization with __bf16 and _Float16 float types it was discovered that lldb creates the same CompilerType for them. This can cause an infinite recursion error, if one tries to create two struct specializations with these types and then inherit one specialization from another. This is an example, provided by @<!-- -->Michael137:

```c++
template <typename T> struct Foo;

template <> struct Foo<__bf16> {};

template <> struct Foo<_Float16> : Foo<__bf16> {};

int main() {
  Foo<_Float16> f1;
  return 0;
}
```

---
Full diff: https://github.com/llvm/llvm-project/pull/157674.diff


2 Files Affected:

- (modified) lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp (+7) 
- (modified) lldb/test/API/lang/cpp/template-arguments/TestCppTemplateArguments.py (+1-1) 


``````````diff
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index c4a917f59fb88..804ddd042574e 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -959,6 +959,12 @@ CompilerType TypeSystemClang::GetBuiltinTypeForDWARFEncodingAndBitSize(
     if (type_name == "long double" &&
         QualTypeMatchesBitSize(bit_size, ast, ast.LongDoubleTy))
       return GetType(ast.LongDoubleTy);
+    if (type_name == "__bf16" &&
+        QualTypeMatchesBitSize(bit_size, ast, ast.BFloat16Ty))
+      return GetType(ast.BFloat16Ty);
+    if (type_name == "_Float16" &&
+        QualTypeMatchesBitSize(bit_size, ast, ast.Float16Ty))
+      return GetType(ast.Float16Ty);
     // As Rust currently uses `TypeSystemClang`, match `f128` here as well so it
     // doesn't get misinterpreted as `long double` on targets where they are
     // the same size but different formats.
@@ -1791,6 +1797,7 @@ bool TypeSystemClang::RecordHasFields(const RecordDecl *record_decl) {
     for (base_class = cxx_record_decl->bases_begin(),
         base_class_end = cxx_record_decl->bases_end();
          base_class != base_class_end; ++base_class) {
+      assert(record_decl != base_class->getType()->getAsCXXRecordDecl());
       if (RecordHasFields(base_class->getType()->getAsCXXRecordDecl()))
         return true;
     }
diff --git a/lldb/test/API/lang/cpp/template-arguments/TestCppTemplateArguments.py b/lldb/test/API/lang/cpp/template-arguments/TestCppTemplateArguments.py
index eac7b5ef1099a..f26d382bf8582 100644
--- a/lldb/test/API/lang/cpp/template-arguments/TestCppTemplateArguments.py
+++ b/lldb/test/API/lang/cpp/template-arguments/TestCppTemplateArguments.py
@@ -82,7 +82,7 @@ def test(self):
         value = self.expect_expr("temp7", result_type="Foo<__fp16, __fp16>")
         self.assertFalse(value.GetType().GetTemplateArgumentValue(target, 1))
 
-        value = self.expect_expr("temp8", result_type="Foo<__fp16, __fp16>")
+        value = self.expect_expr("temp8", result_type="Foo<__bf16, __bf16>")
         self.assertFalse(value.GetType().GetTemplateArgumentValue(target, 1))
 
         value = self.expect_expr("temp9", result_type="Bar<double, 1.200000e+00>")

``````````

</details>


https://github.com/llvm/llvm-project/pull/157674