1 files changed, 207 insertions, 0 deletions
diff --git a/lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp b/lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp
new file mode 100644
index 0000000000000..5cfd978774fd0
--- /dev/null
+++ b/lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp
@@ -0,0 +1,207 @@
+//===-- BlockPointer.cpp ----------------------------------------*- C++ -*-===//
+//
+// 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 "BlockPointer.h"
+
+#include "lldb/Core/ValueObject.h"
+#include "lldb/DataFormatters/FormattersHelpers.h"
+#include "lldb/Symbol/ClangASTContext.h"
+#include "lldb/Symbol/ClangASTImporter.h"
+#include "lldb/Symbol/CompilerType.h"
+#include "lldb/Symbol/TypeSystem.h"
+#include "lldb/Target/Target.h"
+
+#include "lldb/Utility/LLDBAssert.h"
+#include "lldb/Utility/Log.h"
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::formatters;
+
+namespace lldb_private {
+namespace formatters {
+
+class BlockPointerSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
+public:
+  BlockPointerSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
+      : SyntheticChildrenFrontEnd(*valobj_sp), m_block_struct_type() {
+    CompilerType block_pointer_type(m_backend.GetCompilerType());
+    CompilerType function_pointer_type;
+    block_pointer_type.IsBlockPointerType(&function_pointer_type);
+
+    TargetSP target_sp(m_backend.GetTargetSP());
+
+    if (!target_sp) {
+      return;
+    }
+
+    auto type_system_or_err = target_sp->GetScratchTypeSystemForLanguage(
+        lldb::eLanguageTypeC_plus_plus);
+    if (auto err = type_system_or_err.takeError()) {
+      LLDB_LOG_ERROR(
+          lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DATAFORMATTERS),
+          std::move(err), "Failed to get scratch ClangASTContext");
+      return;
+    }
+
+    ClangASTContext *clang_ast_context =
+        llvm::dyn_cast<ClangASTContext>(&type_system_or_err.get());
+
+    if (!clang_ast_context) {
+      return;
+    }
+
+    ClangASTImporterSP clang_ast_importer = target_sp->GetClangASTImporter();
+
+    if (!clang_ast_importer) {
+      return;
+    }
+
+    const char *const isa_name("__isa");
+    const CompilerType isa_type =
+        clang_ast_context->GetBasicType(lldb::eBasicTypeObjCClass);
+    const char *const flags_name("__flags");
+    const CompilerType flags_type =
+        clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
+    const char *const reserved_name("__reserved");
+    const CompilerType reserved_type =
+        clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
+    const char *const FuncPtr_name("__FuncPtr");
+    const CompilerType FuncPtr_type =
+        clang_ast_importer->CopyType(*clang_ast_context, function_pointer_type);
+
+    m_block_struct_type = clang_ast_context->CreateStructForIdentifier(
+        ConstString(), {{isa_name, isa_type},
+                        {flags_name, flags_type},
+                        {reserved_name, reserved_type},
+                        {FuncPtr_name, FuncPtr_type}});
+  }
+
+  ~BlockPointerSyntheticFrontEnd() override = default;
+
+  size_t CalculateNumChildren() override {
+    const bool omit_empty_base_classes = false;
+    return m_block_struct_type.GetNumChildren(omit_empty_base_classes, nullptr);
+  }
+
+  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override {
+    if (!m_block_struct_type.IsValid()) {
+      return lldb::ValueObjectSP();
+    }
+
+    if (idx >= CalculateNumChildren()) {
+      return lldb::ValueObjectSP();
+    }
+
+    const bool thread_and_frame_only_if_stopped = true;
+    ExecutionContext exe_ctx = m_backend.GetExecutionContextRef().Lock(
+        thread_and_frame_only_if_stopped);
+    const bool transparent_pointers = false;
+    const bool omit_empty_base_classes = false;
+    const bool ignore_array_bounds = false;
+    ValueObject *value_object = nullptr;
+
+    std::string child_name;
+    uint32_t child_byte_size = 0;
+    int32_t child_byte_offset = 0;
+    uint32_t child_bitfield_bit_size = 0;
+    uint32_t child_bitfield_bit_offset = 0;
+    bool child_is_base_class = false;
+    bool child_is_deref_of_parent = false;
+    uint64_t language_flags = 0;
+
+    const CompilerType child_type =
+        m_block_struct_type.GetChildCompilerTypeAtIndex(
+            &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
+            ignore_array_bounds, child_name, child_byte_size, child_byte_offset,
+            child_bitfield_bit_size, child_bitfield_bit_offset,
+            child_is_base_class, child_is_deref_of_parent, value_object,
+            language_flags);
+
+    ValueObjectSP struct_pointer_sp =
+        m_backend.Cast(m_block_struct_type.GetPointerType());
+
+    if (!struct_pointer_sp) {
+      return lldb::ValueObjectSP();
+    }
+
+    Status err;
+    ValueObjectSP struct_sp = struct_pointer_sp->Dereference(err);
+
+    if (!struct_sp || !err.Success()) {
+      return lldb::ValueObjectSP();
+    }
+
+    ValueObjectSP child_sp(struct_sp->GetSyntheticChildAtOffset(
+        child_byte_offset, child_type, true,
+        ConstString(child_name.c_str(), child_name.size())));
+
+    return child_sp;
+  }
+
+  // return true if this object is now safe to use forever without ever
+  // updating again; the typical (and tested) answer here is 'false'
+  bool Update() override { return false; }
+
+  // maybe return false if the block pointer is, say, null
+  bool MightHaveChildren() override { return true; }
+
+  size_t GetIndexOfChildWithName(ConstString name) override {
+    if (!m_block_struct_type.IsValid())
+      return UINT32_MAX;
+
+    const bool omit_empty_base_classes = false;
+    return m_block_struct_type.GetIndexOfChildWithName(name.AsCString(),
+                                                       omit_empty_base_classes);
+  }
+
+private:
+  CompilerType m_block_struct_type;
+};
+
+} // namespace formatters
+} // namespace lldb_private
+
+bool lldb_private::formatters::BlockPointerSummaryProvider(
+    ValueObject &valobj, Stream &s, const TypeSummaryOptions &) {
+  lldb_private::SyntheticChildrenFrontEnd *synthetic_children =
+      BlockPointerSyntheticFrontEndCreator(nullptr, valobj.GetSP());
+  if (!synthetic_children) {
+    return false;
+  }
+
+  synthetic_children->Update();
+
+  static const ConstString s_FuncPtr_name("__FuncPtr");
+
+  lldb::ValueObjectSP child_sp = synthetic_children->GetChildAtIndex(
+      synthetic_children->GetIndexOfChildWithName(s_FuncPtr_name));
+
+  if (!child_sp) {
+    return false;
+  }
+
+  lldb::ValueObjectSP qualified_child_representation_sp =
+      child_sp->GetQualifiedRepresentationIfAvailable(
+          lldb::eDynamicDontRunTarget, true);
+
+  const char *child_value =
+      qualified_child_representation_sp->GetValueAsCString();
+
+  s.Printf("%s", child_value);
+
+  return true;
+}
+
+lldb_private::SyntheticChildrenFrontEnd *
+lldb_private::formatters::BlockPointerSyntheticFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  if (!valobj_sp)
+    return nullptr;
+  return new BlockPointerSyntheticFrontEnd(valobj_sp);
+}