[lldb-vscode] Allow specifying a custom escape prefix for LLDB commands

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

@@ -731,6 +731,7 @@ def request_launch(
         postRunCommands=None,
         enableAutoVariableSummaries=False,
         enableSyntheticChildDebugging=False,
+        commandEscapePrefix="`",
     ):
         args_dict = {"program": program}
         if args:
@@ -774,6 +775,7 @@ def request_launch(
             args_dict["postRunCommands"] = postRunCommands
         args_dict["enableAutoVariableSummaries"] = enableAutoVariableSummaries
         args_dict["enableSyntheticChildDebugging"] = enableSyntheticChildDebugging
+        args_dict["commandEscapePrefix"] = commandEscapePrefix
         command_dict = {"command": "launch", "type": "request", "arguments": args_dict}
         response = self.send_recv(command_dict)
 
@@ -1015,7 +1017,12 @@ def terminate(self):
 
 class DebugAdaptorServer(DebugCommunication):
     def __init__(
-        self, executable=None, port=None, init_commands=[], log_file=None, env=None
+        self,
+        executable=None,
+        port=None,
+        init_commands=[],
+        log_file=None,
+        env=None,
     ):
         self.process = None
         if executable is not None:

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

@@ -351,6 +351,7 @@ def launch(
         postRunCommands=None,
         enableAutoVariableSummaries=False,
         enableSyntheticChildDebugging=False,
+        commandEscapePrefix="`",
     ):
         """Sending launch request to dap"""
 
@@ -389,6 +390,7 @@ def cleanup():
             postRunCommands=postRunCommands,
             enableAutoVariableSummaries=enableAutoVariableSummaries,
             enableSyntheticChildDebugging=enableSyntheticChildDebugging,
+            commandEscapePrefix=commandEscapePrefix,
         )
 
         if expectFailure:
@@ -425,6 +427,7 @@ def build_and_launch(
         lldbDAPEnv=None,
         enableAutoVariableSummaries=False,
         enableSyntheticChildDebugging=False,
+        commandEscapePrefix="`",
     ):
         """Build the default Makefile target, create the DAP debug adaptor,
         and launch the process.
@@ -455,4 +458,5 @@ def build_and_launch(
             postRunCommands=postRunCommands,
             enableAutoVariableSummaries=enableAutoVariableSummaries,
             enableSyntheticChildDebugging=enableSyntheticChildDebugging,
+            commandEscapePrefix=commandEscapePrefix,
         )

lldb/test/API/tools/lldb-dap/console/TestDAP_console.py

@@ -3,16 +3,18 @@
 """
 
 import dap_server
+import lldbdap_testcase
+from lldbsuite.test import lldbutil
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
-from lldbsuite.test import lldbutil
-import lldbdap_testcase
 
 
 class TestDAP_console(lldbdap_testcase.DAPTestCaseBase):
-    def check_lldb_command(self, lldb_command, contains_string, assert_msg):
+    def check_lldb_command(
+        self, lldb_command, contains_string, assert_msg, command_escape_prefix="`"
+    ):
         response = self.dap_server.request_evaluate(
-            "`%s" % (lldb_command), context="repl"
+            f"{command_escape_prefix}{lldb_command}", context="repl"
         )
         output = response["body"]["result"]
         self.assertIn(
@@ -68,3 +70,37 @@ def test_scopes_variables_setVariable_evaluate(self):
         # currently selected frame.
 
         self.check_lldb_command("frame select", "frame #1", "frame 1 is selected")
+
+    @skipIfWindows
+    @skipIfRemote
+    def test_custom_escape_prefix(self):
+        program = self.getBuildArtifact("a.out")
+        self.build_and_launch(program, commandEscapePrefix="::")
+        source = "main.cpp"
+        breakpoint1_line = line_number(source, "// breakpoint 1")
+        breakpoint_ids = self.set_source_breakpoints(source, [breakpoint1_line])
+        self.continue_to_breakpoints(breakpoint_ids)
+
+        self.check_lldb_command(
+            "help",
+            "For more information on any command",
+            "Help can be invoked",
+            command_escape_prefix="::",
+        )
+
+    @skipIfWindows
+    @skipIfRemote
+    def test_empty_escape_prefix(self):
+        program = self.getBuildArtifact("a.out")
+        self.build_and_launch(program, commandEscapePrefix="")
+        source = "main.cpp"
+        breakpoint1_line = line_number(source, "// breakpoint 1")
+        breakpoint_ids = self.set_source_breakpoints(source, [breakpoint1_line])
+        self.continue_to_breakpoints(breakpoint_ids)
+
+        self.check_lldb_command(
+            "help",
+            "For more information on any command",
+            "Help can be invoked",
+            command_escape_prefix="",
+        )

lldb/tools/lldb-dap/DAP.cpp

@@ -382,9 +382,10 @@ llvm::json::Value DAP::CreateTopLevelScopes() {
 
 ExpressionContext DAP::DetectExpressionContext(lldb::SBFrame &frame,
                                                std::string &text) {
-  // Include ` as an escape hatch.
-  if (!text.empty() && text[0] == '`') {
-    text = text.substr(1);
+  // Include the escape hatch prefix.
+  if (!text.empty() &&
+      llvm::StringRef(text).starts_with(g_dap.command_escape_prefix)) {
+    text = text.substr(g_dap.command_escape_prefix.size());
     return ExpressionContext::Command;
   }
 
@@ -416,7 +417,9 @@ ExpressionContext DAP::DetectExpressionContext(lldb::SBFrame &frame,
         if (!auto_repl_mode_collision_warning) {
           llvm::errs() << "Variable expression '" << text
                        << "' is hiding an lldb command, prefix an expression "
-                          "with ` to ensure it runs as a lldb command.\n";
+                          "with '"
+                       << g_dap.command_escape_prefix
+                       << "' to ensure it runs as a lldb command.\n";
           auto_repl_mode_collision_warning = true;
         }
         return ExpressionContext::Variable;

lldb/tools/lldb-dap/DAP.h

@@ -188,6 +188,7 @@ struct DAP {
   ReplModeRequestHandler repl_mode_request_handler;
   ReplMode repl_mode;
   bool auto_repl_mode_collision_warning;
+  std::string command_escape_prefix = "`";
 
   DAP();
   ~DAP();

lldb/tools/lldb-dap/JSONUtils.cpp

@@ -46,15 +46,17 @@ llvm::StringRef GetAsString(const llvm::json::Value &value) {
 }
 
 // Gets a string from a JSON object using the key, or returns an empty string.
-llvm::StringRef GetString(const llvm::json::Object &obj, llvm::StringRef key) {
+llvm::StringRef GetString(const llvm::json::Object &obj, llvm::StringRef key,
+                          llvm::StringRef defaultValue) {
   if (std::optional<llvm::StringRef> value = obj.getString(key))
     return *value;
-  return llvm::StringRef();
+  return defaultValue;
 }
 
-llvm::StringRef GetString(const llvm::json::Object *obj, llvm::StringRef key) {
+llvm::StringRef GetString(const llvm::json::Object *obj, llvm::StringRef key,
+                          llvm::StringRef defaultValue) {
   if (obj == nullptr)
-    return llvm::StringRef();
+    return defaultValue;
   return GetString(*obj, key);
 }
 

lldb/tools/lldb-dap/JSONUtils.h

@@ -52,12 +52,17 @@ llvm::StringRef GetAsString(const llvm::json::Value &value);
 /// \param[in] key
 ///     The key to use when extracting the value
 ///
+/// \param[in] defaultValue
+///     The default value to return if the key is not present
+///
 /// \return
 ///     A llvm::StringRef that contains the string value for the
-///     specified \a key, or an empty string if there is no key that
+///     specified \a key, or the default value if there is no key that
 ///     matches or if the value is not a string.
-llvm::StringRef GetString(const llvm::json::Object &obj, llvm::StringRef key);
-llvm::StringRef GetString(const llvm::json::Object *obj, llvm::StringRef key);
+llvm::StringRef GetString(const llvm::json::Object &obj, llvm::StringRef key,
+                          llvm::StringRef defaultValue = {});
+llvm::StringRef GetString(const llvm::json::Object *obj, llvm::StringRef key,
+                          llvm::StringRef defaultValue = {});
 
 /// Extract the unsigned integer value for the specified key from
 /// the specified object.

lldb/tools/lldb-dap/lldb-dap.cpp

@@ -651,6 +651,8 @@ void request_attach(const llvm::json::Object &request) {
       GetBoolean(arguments, "enableAutoVariableSummaries", false);
   g_dap.enable_synthetic_child_debugging =
       GetBoolean(arguments, "enableSyntheticChildDebugging", false);
+  g_dap.command_escape_prefix =
+      GetString(arguments, "commandEscapePrefix", "`");
 
   // This is a hack for loading DWARF in .o files on Mac where the .o files
   // in the debug map of the main executable have relative paths which require
@@ -1801,6 +1803,8 @@ void request_launch(const llvm::json::Object &request) {
       GetBoolean(arguments, "enableAutoVariableSummaries", false);
   g_dap.enable_synthetic_child_debugging =
       GetBoolean(arguments, "enableSyntheticChildDebugging", false);
+  g_dap.command_escape_prefix =
+      GetString(arguments, "commandEscapePrefix", "`");
 
   // This is a hack for loading DWARF in .o files on Mac where the .o files
   // in the debug map of the main executable have relative paths which require

lldb/tools/lldb-dap/package.json

@@ -250,6 +250,11 @@
 								"type": "boolean",
 								"description": "If a variable is displayed using a synthetic children, also display the actual contents of the variable at the end under a [raw] entry. This is useful when creating sythetic child plug-ins as it lets you see the actual contents of the variable.",
 								"default": false
+							},
+							"commandEscapePrefix": {
+								"type": "string",
+								"description": "The escape prefix to use for executing regular LLDB commands in the Debug Console, instead of printing variables. Defaults to a back-tick (`). If it's an empty string, then all expression in the Debug Console are treated as regular LLDB commands.",
+								"default": "`"
 							}
 						}
 					},
@@ -339,6 +344,11 @@
 								"type": "boolean",
 								"description": "If a variable is displayed using a synthetic children, also display the actual contents of the variable at the end under a [raw] entry. This is useful when creating sythetic child plug-ins as it lets you see the actual contents of the variable.",
 								"default": false
+							},
+							"commandEscapePrefix": {
+								"type": "string",
+								"description": "The escape prefix character to use for executing regular LLDB commands in the Debug Console, instead of printing variables. Defaults to a back-tick (`). If empty, then all expression in the Debug Console are treated as regular LLDB commands.",
+								"default": "`"
 							}
 						}
 					}