[Lldb-commits] [lldb] [lldb] Add generic string view summary provider (PR #171854)

[Sergei Druzhkov via lldb-commits]

================
@@ -0,0 +1,131 @@
+//===-- GenericStringView.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 "Generic.h"
+#include "LibCxx.h"
+
+#include "lldb/ValueObject/ValueObject.h"
+#include "lldb/lldb-forward.h"
+
+#include "Plugins/Language/CPlusPlus/CxxStringTypes.h"
+#include <tuple>
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::formatters;
+
+using StringElementType = StringPrinter::StringElementType;
+
+enum class StlType {
+  LibCxx,
+  LibStdcpp,
+  MsvcStl,
+};
+
+std::tuple<StlType, lldb::ValueObjectSP, lldb::ValueObjectSP>
+extractStringViewData(ValueObject &valobj) {
+  auto data_sp = valobj.GetChildMemberWithName("_Mydata");
+  if (data_sp)
+    return std::make_tuple(StlType::MsvcStl, data_sp,
+                           valobj.GetChildMemberWithName("_Mysize"));
+  data_sp = valobj.GetChildMemberWithName("_M_str");
+  if (data_sp)
+    return std::make_tuple(StlType::LibStdcpp, data_sp,
+                           valobj.GetChildMemberWithName("_M_len"));
+  return std::make_tuple(
+      StlType::LibCxx,
+      GetChildMemberWithName(valobj,
+                             {ConstString("__data_"), ConstString("__data")}),
+      GetChildMemberWithName(valobj,
+                             {ConstString("__size_"), ConstString("__size")}));
+}
+
+template <StringPrinter::StringElementType element_type>
+static bool formatStringViewImpl(lldb::ValueObjectSP data_sp,
+                                 lldb::ValueObjectSP size_sp, Stream &stream,
+                                 const TypeSummaryOptions &summary_options,
+                                 std::string prefix_token) {
+  if (!data_sp || !size_sp)
+    return false;
+
+  bool success = false;
+  uint64_t size = size_sp->GetValueAsUnsigned(0, &success);
+  if (!success) {
+    stream << "Summary Unavailable";
+    return true;
+  }
+
+  StreamString scratch_stream;
+  success = StringBufferSummaryProvider<element_type>(
+      scratch_stream, summary_options, data_sp, size, prefix_token);
+
+  if (success)
+    stream << scratch_stream.GetData();
+  else
+    stream << "Summary Unavailable";
+  return true;
+}
+
+template <StringElementType element_type>
+static constexpr const char *getPrefixToken() {
+  if constexpr (element_type == StringElementType::ASCII)
+    return "";
+  if constexpr (element_type == StringElementType::UTF8)
+    return "u8";
+  if constexpr (element_type == StringElementType::UTF16)
+    return "u";
+  if constexpr (element_type == StringElementType::UTF32)
+    return "U";
+  llvm_unreachable("invalid element type");
+}
+
+template <StringPrinter::StringElementType element_type>
+bool lldb_private::formatters::GenericStringViewSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  auto [_, data_sp, size_sp] = extractStringViewData(valobj);
+  return formatStringViewImpl<element_type>(data_sp, size_sp, stream, options,
+                                            getPrefixToken<element_type>());
+}
+
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::ASCII>(ValueObject &, Stream &,
+                              const TypeSummaryOptions &);
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::UTF8>(ValueObject &, Stream &,
+                             const TypeSummaryOptions &);
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::UTF16>(ValueObject &, Stream &,
+                              const TypeSummaryOptions &);
+template bool lldb_private::formatters::GenericStringViewSummaryProvider<
+    StringElementType::UTF32>(ValueObject &, Stream &,
+                              const TypeSummaryOptions &);
+
+bool lldb_private::formatters::GenericWStringViewSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  auto [stl, data_sp, size_sp] = extractStringViewData(valobj);
+  if (stl == StlType::LibStdcpp)
+    return formatStringViewImpl<StringElementType::UTF32>(data_sp, size_sp,
+                                                          stream, options, "L");
----------------
DrSergei wrote:

Sorry, It was a typo. I mean we should use utf32 for msvc stl and try to get exact wchar size for libstdcpp and libcxx.

https://github.com/llvm/llvm-project/pull/171854