[Lldb-commits] [lldb] [lldb] Add WebAssembly platform (PR #171507)

[Jonas Devlieghere via lldb-commits]

================
@@ -0,0 +1,210 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 "Plugins/Platform/WebAssembly/PlatformWasm.h"
+#include "Plugins/Process/wasm/ProcessWasm.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Host/ProcessLaunchInfo.h"
+#include "lldb/Host/common/TCPSocket.h"
+#include "lldb/Interpreter/OptionValueProperties.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Target/Target.h"
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/Listener.h"
+#include "lldb/Utility/Log.h"
+#include "llvm/ADT/StringExtras.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+LLDB_PLUGIN_DEFINE(PlatformWasm)
+
+namespace {
+#define LLDB_PROPERTIES_platformwasm
+#include "PlatformWasmProperties.inc"
+
+enum {
+#define LLDB_PROPERTIES_platformwasm
+#include "PlatformWasmPropertiesEnum.inc"
+};
+
+class PluginProperties : public Properties {
+public:
+  PluginProperties() {
+    m_collection_sp = std::make_shared<OptionValueProperties>(
+        PlatformWasm::GetPluginNameStatic());
+    m_collection_sp->Initialize(g_platformwasm_properties);
+  }
+
+  FileSpec GetRuntimePath() const {
+    return GetPropertyAtIndexAs<FileSpec>(ePropertyRuntimePath, {});
+  }
+
+  Args GetRuntimeArgs() const {
+    Args result;
+    m_collection_sp->GetPropertyAtIndexAsArgs(ePropertyRuntimeArgs, result);
+    return result;
+  }
+
+  llvm::StringRef GetPortArg() const {
+    return GetPropertyAtIndexAs<llvm::StringRef>(ePropertyPortArg, {});
+  }
+};
+
+} // namespace
+
+static PluginProperties &GetGlobalProperties() {
+  static PluginProperties g_settings;
+  return g_settings;
+}
+
+llvm::StringRef PlatformWasm::GetPluginDescriptionStatic() {
+  return "Platform for debugging Wasm";
+}
+
+void PlatformWasm::Initialize() {
+  PluginManager::RegisterPlugin(
+      GetPluginNameStatic(), GetPluginDescriptionStatic(),
+      PlatformWasm::CreateInstance, PlatformWasm::DebuggerInitialize);
+}
+
+void PlatformWasm::Terminate() {
+  PluginManager::UnregisterPlugin(PlatformWasm::CreateInstance);
+}
+
+void PlatformWasm::DebuggerInitialize(Debugger &debugger) {
+  if (!PluginManager::GetSettingForPlatformPlugin(debugger,
+                                                  GetPluginNameStatic())) {
+    PluginManager::CreateSettingForPlatformPlugin(
+        debugger, GetGlobalProperties().GetValueProperties(),
+        "Properties for the wasm platform plugin.",
+        /*is_global_property=*/true);
+  }
+}
+
+PlatformSP PlatformWasm::CreateInstance(bool force, const ArchSpec *arch) {
+  Log *log = GetLog(LLDBLog::Platform);
+  LLDB_LOG(log, "force = {0}, arch = ({1}, {2})", force,
+           arch ? arch->GetArchitectureName() : "<null>",
+           arch ? arch->GetTriple().getTriple() : "<null>");
+
+  bool create = force;
+  if (!create && arch && arch->IsValid()) {
+    const llvm::Triple &triple = arch->GetTriple();
+    switch (triple.getArch()) {
+    case llvm::Triple::wasm32:
+    case llvm::Triple::wasm64:
+      create = true;
+      break;
+    default:
+      break;
+    }
+  }
+
+  LLDB_LOG(log, "create = {0}", create);
+  return create ? PlatformSP(new PlatformWasm()) : PlatformSP();
+}
+
+std::vector<ArchSpec>
+PlatformWasm::GetSupportedArchitectures(const ArchSpec &process_host_arch) {
+  return {ArchSpec("wasm32-unknown-unknown-wasm"),
+          ArchSpec("wasm64-unknown-unknown-wasm")};
+}
+
+static auto get_arg_range(const Args &args) {
+  return llvm::make_range(args.GetArgumentArrayRef().begin(),
+                          args.GetArgumentArrayRef().end());
+}
+
+lldb::ProcessSP PlatformWasm::DebugProcess(ProcessLaunchInfo &launch_info,
+                                           Debugger &debugger, Target &target,
+                                           Status &error) {
+  Log *log = GetLog(LLDBLog::Platform);
+
+  const PluginProperties &properties = GetGlobalProperties();
+
+  FileSpec runtime = properties.GetRuntimePath();
+  FileSystem::Instance().ResolveExecutableLocation(runtime);
+
+  if (!FileSystem::Instance().Exists(runtime)) {
+    error = Status::FromErrorStringWithFormatv(
+        "WebAssembly runtime does not exist: {0}", runtime.GetPath());
+    return nullptr;
+  }
+
+  uint16_t port = 0;
+  {
+    TCPSocket listen_socket(true);
+    error = listen_socket.Listen("localhost:0", 5);
+    if (error.Fail())
+      return nullptr;
+    port = listen_socket.GetLocalPortNumber();
+  }
+
+  if (error.Fail())
+    return nullptr;
+
+  Args args({runtime.GetPath(),
+             llvm::formatv("{0}{1}", properties.GetPortArg(), port).str()});
+  args.AppendArguments(properties.GetRuntimeArgs());
+  args.AppendArguments(launch_info.GetArguments());
+
+  launch_info.SetArguments(args, true);
+  launch_info.SetLaunchInSeparateProcessGroup(true);
+  launch_info.GetFlags().Clear(eLaunchFlagDebug);
+
+  auto exit_code = std::make_shared<std::optional<int>>();
+  launch_info.SetMonitorProcessCallback(
+      [=](lldb::pid_t pid, int signal, int status) {
+        LLDB_LOG(
+            log,
+            "WebAssembly runtime exited: pid = {0}, signal = {1}, status = {2}",
+            pid, signal, status);
+        exit_code->emplace(status);
+      });
+
+  // This is automatically done for host platform in
+  // Target::FinalizeFileActions, but we're not a host platform.
+  llvm::Error Err = launch_info.SetUpPtyRedirection();
+  LLDB_LOG_ERROR(log, std::move(Err), "SetUpPtyRedirection failed: {0}");
+
+  LLDB_LOG(log, "{0}", get_arg_range(launch_info.GetArguments()));
+  error = Host::LaunchProcess(launch_info);
+  if (error.Fail())
+    return nullptr;
+
+  ProcessSP process_sp = target.CreateProcess(
+      launch_info.GetListener(), wasm::ProcessWasm::GetPluginNameStatic(),
+      nullptr, true);
+  if (!process_sp) {
+    error = Status::FromErrorString("failed to create WebAssembly process");
+    return nullptr;
+  }
+
+  process_sp->HijackProcessEvents(launch_info.GetHijackListener());
+
+  error = process_sp->ConnectRemote(
+      llvm::formatv("connect://localhost:{0}", port).str());
+  if (error.Fail()) {
+    // If we know the runtime has exited, that's a better error message than
+    // failing to connect.
+    if (*exit_code)
+      error = Status::FromErrorStringWithFormatv(
+          "WebAssembly runtime exited with exit code {0}", **exit_code);
----------------
JDevlieghere wrote:

Funny you mention that, it's what I had originally. I ended up going with this because the runtime exiting is always more interesting:

```
(lldb) run
WebAssembly runtime exited with exit code 1
Timed out connecting to localhost:12345
```

But on the other hand it's not nice to drop an error message so I'll revive it. 

https://github.com/llvm/llvm-project/pull/171507