[lldb-dap] Add data breakpoints for bytes

Author: DrSergei

lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py

@@ -1234,16 +1234,24 @@ def request_setFunctionBreakpoints(self, names, condition=None, hitCondition=Non
         return response
 
     def request_dataBreakpointInfo(
-        self, variablesReference, name, frameIndex=0, threadId=None
+        self, variablesReference, name, size=None, frameIndex=0, threadId=None
     ):
         stackFrame = self.get_stackFrame(frameIndex=frameIndex, threadId=threadId)
         if stackFrame is None:
             return []
-        args_dict = {
-            "variablesReference": variablesReference,
-            "name": name,
-            "frameId": stackFrame["id"],
-        }
+        args_dict = (
+            {
+                "variablesReference": variablesReference,
+                "name": name,
+                "frameId": stackFrame["id"],
+            }
+            if size is None
+            else {
+                "bytes": size,
+                "name": name,
+                "asAddress": True,
+            }
+        )
         command_dict = {
             "command": "dataBreakpointInfo",
             "type": "request",

lldb/test/API/tools/lldb-dap/databreakpoint/TestDAP_setDataBreakpoints.py

@@ -171,3 +171,55 @@ def test_functionality(self):
         self.continue_to_next_stop()
         x_val = self.dap_server.get_local_variable_value("x")
         self.assertEqual(x_val, "10")
+
+    @skipIfWindows
+    def test_bytes(self):
+        """Tests setting data breakpoints on memory range."""
+        program = self.getBuildArtifact("a.out")
+        self.build_and_launch(program)
+        source = "main.cpp"
+        first_loop_break_line = line_number(source, "// first loop breakpoint")
+        self.set_source_breakpoints(source, [first_loop_break_line])
+        self.continue_to_next_stop()
+        # Test write watchpoints on x, arr[2]
+        x = self.dap_server.get_local_variable("x")
+        response_x = self.dap_server.request_dataBreakpointInfo(
+            0, x["memoryReference"], 4
+        )
+        arr_2 = self.dap_server.get_local_variable_child("arr", "[2]")
+        response_arr_2 = self.dap_server.request_dataBreakpointInfo(
+            0, arr_2["memoryReference"], 4
+        )
+
+        # Test response from dataBreakpointInfo request.
+        self.assertEqual(
+            response_x["body"]["dataId"].split("/"), [x["memoryReference"][2:], "4"]
+        )
+        self.assertEqual(response_x["body"]["accessTypes"], self.accessTypes)
+        self.assertEqual(
+            response_arr_2["body"]["dataId"].split("/"),
+            [arr_2["memoryReference"][2:], "4"],
+        )
+        self.assertEqual(response_arr_2["body"]["accessTypes"], self.accessTypes)
+        dataBreakpoints = [
+            {"dataId": response_x["body"]["dataId"], "accessType": "write"},
+            {"dataId": response_arr_2["body"]["dataId"], "accessType": "write"},
+        ]
+        set_response = self.dap_server.request_setDataBreakpoint(dataBreakpoints)
+        self.assertEqual(
+            set_response["body"]["breakpoints"],
+            [{"verified": True}, {"verified": True}],
+        )
+
+        self.continue_to_next_stop()
+        x_val = self.dap_server.get_local_variable_value("x")
+        i_val = self.dap_server.get_local_variable_value("i")
+        self.assertEqual(x_val, "2")
+        self.assertEqual(i_val, "1")
+
+        self.continue_to_next_stop()
+        arr_2 = self.dap_server.get_local_variable_child("arr", "[2]")
+        i_val = self.dap_server.get_local_variable_value("i")
+        self.assertEqual(arr_2["value"], "42")
+        self.assertEqual(i_val, "2")
+        self.dap_server.request_setDataBreakpoint([])

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

@@ -16,14 +16,27 @@
 
 namespace lldb_dap {
 
+static bool CheckAddress(DAP &dap, lldb::addr_t load_addr) {
+  lldb::SBMemoryRegionInfo region;
+  lldb::SBError err =
+      dap.target.GetProcess().GetMemoryRegionInfo(load_addr, region);
+  // Only lldb-server supports "qMemoryRegionInfo". So, don't fail this
+  // request if SBProcess::GetMemoryRegionInfo returns error.
+  if (err.Success()) {
+    if (!(region.IsReadable() || region.IsWritable())) {
+      return false;
+    }
+  }
+  return true;
+}
+
 /// Obtains information on a possible data breakpoint that could be set on an
 /// expression or variable. Clients should only call this request if the
 /// corresponding capability supportsDataBreakpoints is true.
 llvm::Expected<protocol::DataBreakpointInfoResponseBody>
 DataBreakpointInfoRequestHandler::Run(
     const protocol::DataBreakpointInfoArguments &args) const {
   protocol::DataBreakpointInfoResponseBody response;
-  lldb::SBFrame frame = dap.GetLLDBFrame(args.frameId);
   lldb::SBValue variable = dap.variables.FindVariable(
       args.variablesReference.value_or(0), args.name);
   std::string addr, size;
@@ -43,7 +56,8 @@ DataBreakpointInfoRequestHandler::Run(
       addr = llvm::utohexstr(load_addr);
       size = llvm::utostr(byte_size);
     }
-  } else if (args.variablesReference.value_or(0) == 0 && frame.IsValid()) {
+  } else if (lldb::SBFrame frame = dap.GetLLDBFrame(args.frameId);
+             args.variablesReference.value_or(0) == 0 && frame.IsValid()) {
     lldb::SBValue value = frame.EvaluateExpression(args.name.c_str());
     if (value.GetError().Fail()) {
       lldb::SBError error = value.GetError();
@@ -58,24 +72,28 @@ DataBreakpointInfoRequestHandler::Run(
       if (data.IsValid()) {
         size = llvm::utostr(data.GetByteSize());
         addr = llvm::utohexstr(load_addr);
-        lldb::SBMemoryRegionInfo region;
-        lldb::SBError err =
-            dap.target.GetProcess().GetMemoryRegionInfo(load_addr, region);
-        // Only lldb-server supports "qMemoryRegionInfo". So, don't fail this
-        // request if SBProcess::GetMemoryRegionInfo returns error.
-        if (err.Success()) {
-          if (!(region.IsReadable() || region.IsWritable())) {
-            is_data_ok = false;
-            response.description = "memory region for address " + addr +
-                                   " has no read or write permissions";
-          }
+        if (!CheckAddress(dap, load_addr)) {
+          is_data_ok = false;
+          response.description = "memory region for address " + addr +
+                                 " has no read or write permissions";
         }
       } else {
         is_data_ok = false;
         response.description =
             "unable to get byte size for expression: " + args.name;
       }
     }
+  } else if (args.asAddress) {
+    size = llvm::utostr(args.bytes.value_or(1));
+    if (llvm::StringRef(args.name).starts_with("0x"))
+      addr = args.name.substr(2);
+    else
+      addr = llvm::utohexstr(std::stoull(args.name));
+    if (!CheckAddress(dap, std::stoull(addr, 0, 16))) {
+      is_data_ok = false;
+      response.description = "memory region for address " + addr +
+                             " has no read or write permissions";
+    }
   } else {
     is_data_ok = false;
     response.description = "variable not found: " + args.name;

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

@@ -432,6 +432,9 @@ class DataBreakpointInfoRequestHandler
 public:
   using RequestHandler::RequestHandler;
   static llvm::StringLiteral GetCommand() { return "dataBreakpointInfo"; }
+  FeatureSet GetSupportedFeatures() const override {
+    return {protocol::eAdapterFeatureDataBreakpointBytes};
+  }
   llvm::Expected<protocol::DataBreakpointInfoResponseBody>
   Run(const protocol::DataBreakpointInfoArguments &args) const override;
 };