[llvm] [lldb] DEBUGINFOD based DWP acquisition for LLDB (PR #70996)

[Greg Clayton via llvm-commits]

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@@ -0,0 +1,154 @@
+//===-- SymbolLocatorDebuginfod.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 "SymbolLocatorDebuginfod.h"
+
+#include <cstring>
+#include <optional>
+
+#include "Plugins/ObjectFile/wasm/ObjectFileWasm.h"
+#include "lldb/Core/Debugger.h"
+#include "lldb/Core/Module.h"
+#include "lldb/Core/ModuleList.h"
+#include "lldb/Core/ModuleSpec.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/Progress.h"
+#include "lldb/Core/Section.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Host/Host.h"
+#include "lldb/Symbol/ObjectFile.h"
+#include "lldb/Target/Target.h"
+#include "lldb/Utility/ArchSpec.h"
+#include "lldb/Utility/DataBuffer.h"
+#include "lldb/Utility/DataExtractor.h"
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/Log.h"
+#include "lldb/Utility/StreamString.h"
+#include "lldb/Utility/Timer.h"
+#include "lldb/Utility/UUID.h"
+
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/Debuginfod/HTTPClient.h"
+#include "llvm/Debuginfod/Debuginfod.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/ThreadPool.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+LLDB_PLUGIN_DEFINE(SymbolLocatorDebuginfod)
+
+namespace {
+
+#define LLDB_PROPERTIES_symbollocatordebuginfod
+#include "SymbolLocatorDebuginfodProperties.inc"
+
+enum {
+#define LLDB_PROPERTIES_symbollocatordebuginfod
+#include "SymbolLocatorDebuginfodPropertiesEnum.inc"
+};
+
+class PluginProperties : public Properties {
+public:
+  static llvm::StringRef GetSettingName() {
+    return SymbolLocatorDebuginfod::GetPluginNameStatic();
+  }
+
+  PluginProperties() {
+    m_collection_sp = std::make_shared<OptionValueProperties>(GetSettingName());
+    m_collection_sp->Initialize(g_symbollocatordebuginfod_properties);
+    m_collection_sp->SetValueChangedCallback(
+        ePropertyURLs, [this] { URLsChangedCallback(); }
+    );
+  }
+
+  Args GetDebugInfoDURLs() const {
+    Args urls;
+    m_collection_sp->GetPropertyAtIndexAsArgs(ePropertyURLs, urls);
+    return urls;
+  }
+
+private:
+  void URLsChangedCallback() {
+    Args urls = GetDebugInfoDURLs();
+    llvm::SmallVector<llvm::StringRef> dbginfod_urls;
+    llvm::transform(urls, dbginfod_urls.end(),
+                    [](const auto &obj) { return obj.ref(); });
+    llvm::setDefaultDebuginfodUrls(dbginfod_urls);
+  }
+};
+
+} // namespace
+
+
+SymbolLocatorDebuginfod::SymbolLocatorDebuginfod() : SymbolLocator() {}
+
+void SymbolLocatorDebuginfod::Initialize() {
+  PluginManager::RegisterPlugin(
+      GetPluginNameStatic(), GetPluginDescriptionStatic(), CreateInstance,
+      LocateExecutableObjectFile, LocateExecutableSymbolFile,
+      DownloadObjectAndSymbolFile);
+  // There's a "safety" concern on this:
+  // Does plugin initialization occur while things are still single threaded?
----------------
clayborg wrote:

This Initialize() function will get called when `lldb::SBDebugger::Initialize()` is called for the first time. `lldb::SBDebugger::Initialize()` and `lldb::SBDebugger::Terminate()` are ref counted, and only the first call will call `lldb::SBDebugger::Initialize()`. Since LLDB is a shared library, we shouldn't do any work unless clients ask for it. So it really depends on what program is loading LLDB. Command line lldb will init on the main thread right away, so will `lldb-vscode`/`lldb-dap` (VS Code IDE), so will `lldb-rpc-server` (Xcode), not sure about Android Studio or other IDEs

https://github.com/llvm/llvm-project/pull/70996