[Lldb-commits] [lldb] [LLDB][libc++] Adds valarray proxy data formatters. (PR #88613)

[Michael Buch via lldb-commits]

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@@ -0,0 +1,194 @@
+//===-- LibCxxProxyArray.cpp-----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "LibCxx.h"
+
+#include "lldb/Core/ValueObject.h"
+#include "lldb/DataFormatters/FormattersHelpers.h"
+#include <optional>
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::formatters;
+
+namespace lldb_private {
+namespace formatters {
+
+/// Data formatter for libc++'s std::"proxy_array".
+///
+/// A proxy_array's are created by using:
+///   std::gslice_array   operator[](const std::gslice& gslicearr);
+///   std::mask_array     operator[](const std::valarray<bool>& boolarr);
+///   std::indirect_array operator[](const std::valarray<std::size_t>& indarr);
+///
+/// These arrays have the following members:
+/// - __vp_ points to std::valarray::__begin_
+/// - __1d_ an array of offsets of the elements from @a __vp_
+class LibcxxStdProxyArraySyntheticFrontEnd : public SyntheticChildrenFrontEnd {
+public:
+  LibcxxStdProxyArraySyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
+
+  ~LibcxxStdProxyArraySyntheticFrontEnd() override;
+
+  llvm::Expected<uint32_t> CalculateNumChildren() override;
+
+  lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
+
+  lldb::ChildCacheState Update() override;
+
+  bool MightHaveChildren() override;
+
+  size_t GetIndexOfChildWithName(ConstString name) override;
+
+private:
+  /// A non-owning pointer to the array's __vp_.
+  ValueObject *m_base = nullptr;
+  /// The type of the array's template argument T.
+  CompilerType m_element_type;
+  /// The sizeof the array's template argument T.
+  uint32_t m_element_size = 0;
+
+  /// A non-owning pointer to the array's __1d_.__begin_.
+  ValueObject *m_start = nullptr;
+  /// A non-owning pointer to the array's __1d_.__end_.
+  ValueObject *m_finish = nullptr;
+  /// The type of the __1d_ array's template argument T (size_t).
+  CompilerType m_element_type_size_t;
+  /// The sizeof the __1d_ array's template argument T (size_t)
+  uint32_t m_element_size_size_t = 0;
+};
+
+} // namespace formatters
+} // namespace lldb_private
+
+lldb_private::formatters::LibcxxStdProxyArraySyntheticFrontEnd::
+    LibcxxStdProxyArraySyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
+    : SyntheticChildrenFrontEnd(*valobj_sp), m_element_type() {
+  if (valobj_sp)
+    Update();
+}
+
+lldb_private::formatters::LibcxxStdProxyArraySyntheticFrontEnd::
+    ~LibcxxStdProxyArraySyntheticFrontEnd() {
+  // these need to stay around because they are child objects who will follow
+  // their parent's life cycle
+  // delete m_base;
+}
+
+llvm::Expected<uint32_t> lldb_private::formatters::
+    LibcxxStdProxyArraySyntheticFrontEnd::CalculateNumChildren() {
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Michael137 wrote:

This is outside the scope of this PR but eventually we might want to pull this out into a helper or something since we have this implementation across multiple formatters now. Same with `GetChildAtIndex`.

https://github.com/llvm/llvm-project/pull/88613