Re-land [lldb-dap] Add support for data breakpoint. (#81909)

This implements functionality to handle DataBreakpointInfo request and
SetDataBreakpoints request.

Previous commit
8c56e78
was reverted because setting 1 byte watchpoint failed in the new test on
ARM64. So, I changed the test to setting 4 byte watchpoint instead, and
hope this won't break it again. It also adds the fixes from
#81680.

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

@@ -501,6 +501,18 @@ def get_local_variable_value(self, name, frameIndex=0, threadId=None):
             return variable["value"]
         return None
 
+    def get_local_variable_child(self, name, child_name, frameIndex=0, threadId=None):
+        local = self.get_local_variable(name, frameIndex, threadId)
+        if local["variablesReference"] == 0:
+            return None
+        children = self.request_variables(local["variablesReference"])["body"][
+            "variables"
+        ]
+        for child in children:
+            if child["name"] == child_name:
+                return child
+        return None
+
     def replay_packets(self, replay_file_path):
         f = open(replay_file_path, "r")
         mode = "invalid"
@@ -895,6 +907,41 @@ def request_setFunctionBreakpoints(self, names, condition=None, hitCondition=Non
         }
         return self.send_recv(command_dict)
 
+    def request_dataBreakpointInfo(
+        self, variablesReference, name, 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"],
+        }
+        command_dict = {
+            "command": "dataBreakpointInfo",
+            "type": "request",
+            "arguments": args_dict,
+        }
+        return self.send_recv(command_dict)
+
+    def request_setDataBreakpoint(self, dataBreakpoints):
+        """dataBreakpoints is a list of dictionary with following fields:
+        {
+            dataId: (address in hex)/(size in bytes)
+            accessType: read/write/readWrite
+            [condition]: string
+            [hitCondition]: string
+        }
+        """
+        args_dict = {"breakpoints": dataBreakpoints}
+        command_dict = {
+            "command": "setDataBreakpoints",
+            "type": "request",
+            "arguments": args_dict,
+        }
+        return self.send_recv(command_dict)
+
     def request_compileUnits(self, moduleId):
         args_dict = {"moduleId": moduleId}
         command_dict = {

lldb/test/API/tools/lldb-dap/databreakpoint/Makefile

@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules

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

@@ -0,0 +1,131 @@
+"""
+Test lldb-dap dataBreakpointInfo and setDataBreakpoints requests
+"""
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+import lldbdap_testcase
+
+
+class TestDAP_setDataBreakpoints(lldbdap_testcase.DAPTestCaseBase):
+    def setUp(self):
+        lldbdap_testcase.DAPTestCaseBase.setUp(self)
+        self.accessTypes = ["read", "write", "readWrite"]
+
+    @skipIfWindows
+    @skipIfRemote
+    def test_expression(self):
+        """Tests setting data breakpoints on expression."""
+        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()
+        self.dap_server.get_stackFrame()
+        # Test setting write watchpoint using expressions: &x, arr+2
+        response_x = self.dap_server.request_dataBreakpointInfo(0, "&x")
+        response_arr_2 = self.dap_server.request_dataBreakpointInfo(0, "arr+2")
+        # Test response from dataBreakpointInfo request.
+        self.assertEquals(response_x["body"]["dataId"].split("/")[1], "4")
+        self.assertEquals(response_x["body"]["accessTypes"], self.accessTypes)
+        self.assertEquals(response_arr_2["body"]["dataId"].split("/")[1], "4")
+        self.assertEquals(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.assertEquals(
+            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.assertEquals(x_val, "2")
+        self.assertEquals(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.assertEquals(arr_2["value"], "42")
+        self.assertEquals(i_val, "2")
+
+    @skipIfWindows
+    @skipIfRemote
+    def test_functionality(self):
+        """Tests setting data breakpoints on variable."""
+        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()
+        self.dap_server.get_local_variables()
+        # Test write watchpoints on x, arr[2]
+        response_x = self.dap_server.request_dataBreakpointInfo(1, "x")
+        arr = self.dap_server.get_local_variable("arr")
+        response_arr_2 = self.dap_server.request_dataBreakpointInfo(
+            arr["variablesReference"], "[2]"
+        )
+
+        # Test response from dataBreakpointInfo request.
+        self.assertEquals(response_x["body"]["dataId"].split("/")[1], "4")
+        self.assertEquals(response_x["body"]["accessTypes"], self.accessTypes)
+        self.assertEquals(response_arr_2["body"]["dataId"].split("/")[1], "4")
+        self.assertEquals(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.assertEquals(
+            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.assertEquals(x_val, "2")
+        self.assertEquals(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.assertEquals(arr_2["value"], "42")
+        self.assertEquals(i_val, "2")
+        self.dap_server.request_setDataBreakpoint([])
+
+        # Test hit condition
+        second_loop_break_line = line_number(source, "// second loop breakpoint")
+        breakpoint_ids = self.set_source_breakpoints(source, [second_loop_break_line])
+        self.continue_to_breakpoints(breakpoint_ids)
+        dataBreakpoints = [
+            {
+                "dataId": response_x["body"]["dataId"],
+                "accessType": "write",
+                "hitCondition": "2",
+            }
+        ]
+        set_response = self.dap_server.request_setDataBreakpoint(dataBreakpoints)
+        self.assertEquals(set_response["body"]["breakpoints"], [{"verified": True}])
+        self.continue_to_next_stop()
+        x_val = self.dap_server.get_local_variable_value("x")
+        self.assertEquals(x_val, "3")
+
+        # Test condition
+        dataBreakpoints = [
+            {
+                "dataId": response_x["body"]["dataId"],
+                "accessType": "write",
+                "condition": "x==10",
+            }
+        ]
+        set_response = self.dap_server.request_setDataBreakpoint(dataBreakpoints)
+        self.assertEquals(set_response["body"]["breakpoints"], [{"verified": True}])
+        self.continue_to_next_stop()
+        x_val = self.dap_server.get_local_variable_value("x")
+        self.assertEquals(x_val, "10")

lldb/test/API/tools/lldb-dap/databreakpoint/main.cpp

@@ -0,0 +1,17 @@
+int main(int argc, char const *argv[]) {
+  // Test for data breakpoint
+  int x = 0;
+  int arr[4] = {1, 2, 3, 4};
+  for (int i = 0; i < 5; ++i) { // first loop breakpoint
+    if (i == 1) {
+      x = i + 1;
+    } else if (i == 2) {
+      arr[i] = 42;
+    }
+  }
+
+  x = 1;
+  for (int i = 0; i < 10; ++i) { // second loop breakpoint
+    ++x;
+  }
+}

lldb/tools/lldb-dap/CMakeLists.txt

@@ -37,6 +37,7 @@ add_lldb_tool(lldb-dap
   RunInTerminal.cpp
   SourceBreakpoint.cpp
   DAP.cpp
+  Watchpoint.cpp
 
   LINK_LIBS
     liblldb

lldb/tools/lldb-dap/DAPForward.h

@@ -14,6 +14,7 @@ struct BreakpointBase;
 struct ExceptionBreakpoint;
 struct FunctionBreakpoint;
 struct SourceBreakpoint;
+struct Watchpoint;
 } // namespace lldb_dap
 
 namespace lldb {
@@ -39,6 +40,7 @@ class SBStringList;
 class SBTarget;
 class SBThread;
 class SBValue;
+class SBWatchpoint;
 } // namespace lldb
 
 #endif

lldb/tools/lldb-dap/Watchpoint.cpp

@@ -0,0 +1,48 @@
+//===-- Watchpoint.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 "Watchpoint.h"
+#include "DAP.h"
+#include "JSONUtils.h"
+#include "llvm/ADT/StringExtras.h"
+
+namespace lldb_dap {
+Watchpoint::Watchpoint(const llvm::json::Object &obj) : BreakpointBase(obj) {
+  llvm::StringRef dataId = GetString(obj, "dataId");
+  std::string accessType = GetString(obj, "accessType").str();
+  auto [addr_str, size_str] = dataId.split('/');
+  lldb::addr_t addr;
+  size_t size;
+  llvm::to_integer(addr_str, addr, 16);
+  llvm::to_integer(size_str, size);
+  lldb::SBWatchpointOptions options;
+  options.SetWatchpointTypeRead(accessType != "write");
+  if (accessType != "read")
+    options.SetWatchpointTypeWrite(lldb::eWatchpointWriteTypeOnModify);
+  wp = g_dap.target.WatchpointCreateByAddress(addr, size, options, error);
+  SetCondition();
+  SetHitCondition();
+}
+
+void Watchpoint::SetCondition() { wp.SetCondition(condition.c_str()); }
+
+void Watchpoint::SetHitCondition() {
+  uint64_t hitCount = 0;
+  if (llvm::to_integer(hitCondition, hitCount))
+    wp.SetIgnoreCount(hitCount - 1);
+}
+
+void Watchpoint::CreateJsonObject(llvm::json::Object &object) {
+  if (error.Success()) {
+    object.try_emplace("verified", true);
+  } else {
+    object.try_emplace("verified", false);
+    EmplaceSafeString(object, "message", error.GetCString());
+  }
+}
+} // namespace lldb_dap

lldb/tools/lldb-dap/Watchpoint.h

@@ -0,0 +1,34 @@
+//===-- Watchpoint.h --------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_TOOLS_LLDB_DAP_WATCHPOINT_H
+#define LLDB_TOOLS_LLDB_DAP_WATCHPOINT_H
+
+#include "BreakpointBase.h"
+#include "lldb/API/SBError.h"
+#include "lldb/API/SBWatchpoint.h"
+#include "lldb/API/SBWatchpointOptions.h"
+
+namespace lldb_dap {
+
+struct Watchpoint : public BreakpointBase {
+  // The LLDB breakpoint associated wit this watchpoint.
+  lldb::SBWatchpoint wp;
+  lldb::SBError error;
+
+  Watchpoint() = default;
+  Watchpoint(const llvm::json::Object &obj);
+  Watchpoint(lldb::SBWatchpoint wp) : wp(wp) {}
+
+  void SetCondition() override;
+  void SetHitCondition() override;
+  void CreateJsonObject(llvm::json::Object &object) override;
+};
+} // namespace lldb_dap
+
+#endif