[lldb-dap] Refactor stepping related request handlers (NFC)

lldb/tools/lldb-dap/CMakeLists.txt

@@ -47,8 +47,12 @@ add_lldb_tool(lldb-dap
   Handler/ExceptionInfoRequestHandler.cpp
   Handler/InitializeRequestHandler.cpp
   Handler/LaunchRequestHandler.cpp
+  Handler/NextRequestHandler.cpp
   Handler/RequestHandler.cpp
   Handler/RestartRequestHandler.cpp
+  Handler/StepInRequestHandler.cpp
+  Handler/StepInTargetsRequestHandler.cpp
+  Handler/StepOutRequestHandler.cpp
 
   LINK_LIBS
     liblldb

lldb/tools/lldb-dap/Handler/NextRequestHandler.cpp

@@ -0,0 +1,79 @@
+//===-- NextRequestHandler.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 "DAP.h"
+#include "EventHelper.h"
+#include "JSONUtils.h"
+#include "RequestHandler.h"
+
+namespace lldb_dap {
+
+// "NextRequest": {
+//   "allOf": [ { "$ref": "#/definitions/Request" }, {
+//     "type": "object",
+//     "description": "Next request; value of command field is 'next'. The
+//                     request starts the debuggee to run again for one step.
+//                     The debug adapter first sends the NextResponse and then
+//                     a StoppedEvent (event type 'step') after the step has
+//                     completed.",
+//     "properties": {
+//       "command": {
+//         "type": "string",
+//         "enum": [ "next" ]
+//       },
+//       "arguments": {
+//         "$ref": "#/definitions/NextArguments"
+//       }
+//     },
+//     "required": [ "command", "arguments"  ]
+//   }]
+// },
+// "NextArguments": {
+//   "type": "object",
+//   "description": "Arguments for 'next' request.",
+//   "properties": {
+//     "threadId": {
+//       "type": "integer",
+//       "description": "Execute 'next' for this thread."
+//     },
+//     "granularity": {
+//       "$ref": "#/definitions/SteppingGranularity",
+//       "description": "Stepping granularity. If no granularity is specified, a
+//                       granularity of `statement` is assumed."
+//     }
+//   },
+//   "required": [ "threadId" ]
+// },
+// "NextResponse": {
+//   "allOf": [ { "$ref": "#/definitions/Response" }, {
+//     "type": "object",
+//     "description": "Response to 'next' request. This is just an
+//                     acknowledgement, so no body field is required."
+//   }]
+// }
+void NextRequestHandler::operator()(const llvm::json::Object &request) {
+  llvm::json::Object response;
+  FillResponse(request, response);
+  const auto *arguments = request.getObject("arguments");
+  lldb::SBThread thread = dap.GetLLDBThread(*arguments);
+  if (thread.IsValid()) {
+    // Remember the thread ID that caused the resume so we can set the
+    // "threadCausedFocus" boolean value in the "stopped" events.
+    dap.focus_tid = thread.GetThreadID();
+    if (HasInstructionGranularity(*arguments)) {
+      thread.StepInstruction(/*step_over=*/true);
+    } else {
+      thread.StepOver();
+    }
+  } else {
+    response["success"] = llvm::json::Value(false);
+  }
+  dap.SendJSON(llvm::json::Value(std::move(response)));
+}
+
+} // namespace lldb_dap

lldb/tools/lldb-dap/Handler/RequestHandler.cpp

@@ -225,4 +225,11 @@ void RequestHandler::PrintWelcomeMessage() {
 #endif
 }
 
+bool RequestHandler::HasInstructionGranularity(
+    const llvm::json::Object &request) {
+  if (std::optional<llvm::StringRef> value = request.getString("granularity"))
+    return value == "instruction";
+  return false;
+}
+
 } // namespace lldb_dap

lldb/tools/lldb-dap/Handler/RequestHandler.h

@@ -30,6 +30,7 @@ class RequestHandler {
 
   virtual void operator()(const llvm::json::Object &request) = 0;
 
+protected:
   /// Helpers used by multiple request handlers.
   /// FIXME: Move these into the DAP class?
   /// @{
@@ -48,9 +49,11 @@ class RequestHandler {
   // This way we can reuse the process launching logic for RestartRequest too.
   lldb::SBError LaunchProcess(const llvm::json::Object &request);
 
+  // Check if the step-granularity is `instruction`.
+  bool HasInstructionGranularity(const llvm::json::Object &request);
+
   /// @}
 
-protected:
   DAP &dap;
 };
 
@@ -131,6 +134,34 @@ class RestartRequestHandler : public RequestHandler {
   void operator()(const llvm::json::Object &request) override;
 };
 
+class NextRequestHandler : public RequestHandler {
+public:
+  using RequestHandler::RequestHandler;
+  static llvm::StringLiteral getCommand() { return "next"; }
+  void operator()(const llvm::json::Object &request) override;
+};
+
+class StepInRequestHandler : public RequestHandler {
+public:
+  using RequestHandler::RequestHandler;
+  static llvm::StringLiteral getCommand() { return "stepIn"; }
+  void operator()(const llvm::json::Object &request) override;
+};
+
+class StepInTargetsRequestHandler : public RequestHandler {
+public:
+  using RequestHandler::RequestHandler;
+  static llvm::StringLiteral getCommand() { return "stepInTargets"; }
+  void operator()(const llvm::json::Object &request) override;
+};
+
+class StepOutRequestHandler : public RequestHandler {
+public:
+  using RequestHandler::RequestHandler;
+  static llvm::StringLiteral getCommand() { return "stepOut"; }
+  void operator()(const llvm::json::Object &request) override;
+};
+
 } // namespace lldb_dap
 
 #endif

lldb/tools/lldb-dap/Handler/StepInRequestHandler.cpp

@@ -0,0 +1,96 @@
+//===-- StepInRequestHandler.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 "DAP.h"
+#include "EventHelper.h"
+#include "JSONUtils.h"
+#include "RequestHandler.h"
+
+namespace lldb_dap {
+
+// "StepInRequest": {
+//   "allOf": [ { "$ref": "#/definitions/Request" }, {
+//     "type": "object",
+//     "description": "StepIn request; value of command field is 'stepIn'. The
+//     request starts the debuggee to step into a function/method if possible.
+//     If it cannot step into a target, 'stepIn' behaves like 'next'. The debug
+//     adapter first sends the StepInResponse and then a StoppedEvent (event
+//     type 'step') after the step has completed. If there are multiple
+//     function/method calls (or other targets) on the source line, the optional
+//     argument 'targetId' can be used to control into which target the 'stepIn'
+//     should occur. The list of possible targets for a given source line can be
+//     retrieved via the 'stepInTargets' request.", "properties": {
+//       "command": {
+//         "type": "string",
+//         "enum": [ "stepIn" ]
+//       },
+//       "arguments": {
+//         "$ref": "#/definitions/StepInArguments"
+//       }
+//     },
+//     "required": [ "command", "arguments"  ]
+//   }]
+// },
+// "StepInArguments": {
+//   "type": "object",
+//   "description": "Arguments for 'stepIn' request.",
+//   "properties": {
+//     "threadId": {
+//       "type": "integer",
+//       "description": "Execute 'stepIn' for this thread."
+//     },
+//     "targetId": {
+//       "type": "integer",
+//       "description": "Optional id of the target to step into."
+//     },
+//     "granularity": {
+//       "$ref": "#/definitions/SteppingGranularity",
+//       "description": "Stepping granularity. If no granularity is specified, a
+//                       granularity of `statement` is assumed."
+//     }
+//   },
+//   "required": [ "threadId" ]
+// },
+// "StepInResponse": {
+//   "allOf": [ { "$ref": "#/definitions/Response" }, {
+//     "type": "object",
+//     "description": "Response to 'stepIn' request. This is just an
+//     acknowledgement, so no body field is required."
+//   }]
+// }
+void StepInRequestHandler::operator()(const llvm::json::Object &request) {
+  llvm::json::Object response;
+  FillResponse(request, response);
+  const auto *arguments = request.getObject("arguments");
+
+  std::string step_in_target;
+  uint64_t target_id = GetUnsigned(arguments, "targetId", 0);
+  auto it = dap.step_in_targets.find(target_id);
+  if (it != dap.step_in_targets.end())
+    step_in_target = it->second;
+
+  const bool single_thread = GetBoolean(arguments, "singleThread", false);
+  lldb::RunMode run_mode =
+      single_thread ? lldb::eOnlyThisThread : lldb::eOnlyDuringStepping;
+  lldb::SBThread thread = dap.GetLLDBThread(*arguments);
+  if (thread.IsValid()) {
+    // Remember the thread ID that caused the resume so we can set the
+    // "threadCausedFocus" boolean value in the "stopped" events.
+    dap.focus_tid = thread.GetThreadID();
+    if (HasInstructionGranularity(*arguments)) {
+      thread.StepInstruction(/*step_over=*/false);
+    } else {
+      thread.StepInto(step_in_target.c_str(), run_mode);
+    }
+  } else {
+    response["success"] = llvm::json::Value(false);
+  }
+  dap.SendJSON(llvm::json::Value(std::move(response)));
+}
+
+} // namespace lldb_dap