Have lldb-vscode update the currently selecte thread and frame when it receives a "scopes" request.

[clayborg]

Summary

The IDE has no packets that are sent to lldb-vscode that say which thread and frame are selected. The only way we know is we get a request for variables for a stack frame via a "scopes" request. When we receive this packet we make that thread and frame the selected thread and frame in lldb. This way when people execute lldb commands in the debug console by prefixing the expression with the backtick character, we will have the right thread and frame selected. Previously this was not updated as new stack frames were selected.

[wallace]

I agree with the implementation.
I also find no way notify the IDE that the user has switched to a different thread or frame in the console, and I actually think it's better this way.

lldb/test/API/tools/lldb-vscode/console/TestVSCode_console.py

21

just use lldb_command instead of using a formatted string

57

frame #0

58

select

[wallace]

lldb/test/API/tools/lldb-vscode/console/TestVSCode_console.py

21

I didn't notice the backtick. Forget about this

[clayborg]

Fix typos.

[clayborg]

commit 5998aceda9fdca04db4d9ee390cec660896bf0bf (HEAD -> master, origin/master, origin/HEAD)
Author: Greg Clayton <[e-mail]>
Date: Thu Apr 2 16:30:33 2020 -0700

Have lldb-vscode update the currently selecte thread and frame when it receives a "scopes" request.

Summary: The IDE has no packets that are sent to lldb-vscode that say which thread and frame are selected. The only way we know is we get a request for variables for a stack frame via a "scopes" request. When we receive this packet we make that thread and frame the selected thread and frame in lldb. This way when people execute lldb commands in the debug console by prefixing the expression with the backtick character, we will have the right thread and frame selected. Previously this was not updated as new stack frames were selected.

Reviewers: labath, aadsm, wallace, JDevlieghere

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D77347

[labath]

looks good

lldb/test/API/tools/lldb-vscode/console/TestVSCode_console.py

22

if you used self.assertIn(contains_string, output, assertmsg), then you wouldn't need to repeat the arguments in the assert message.

lldb/test/API/tools/lldb-vscode/console/Makefile

+CXX_SOURCES := main.cpp
+
+include Makefile.rules

lldb/test/API/tools/lldb-vscode/console/TestVSCode_console.py

+"""
+Test lldb-vscode setBreakpoints request
+"""
+
+from __future__ import print_function
+
+import unittest2
+import vscode
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+import lldbvscode_testcase
+
+
+class TestVSCode_console(lldbvscode_testcase.VSCodeTestCaseBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def check_lldb_command(self, lldb_command, contains_string, assert_msg):
+        response = self.vscode.request_evaluate('`%s' % (lldb_command))
+        output = response['body']['result']
+        self.assertTrue(contains_string in output,
+                        ("""Verify %s by checking the command output:\n"""
+                         """'''\n%s'''\nfor the string: "%s" """ % (
+                         assert_msg, output, contains_string)))
+
+    @skipIfWindows
+    @skipIfRemote
+    def test_scopes_variables_setVariable_evaluate(self):
+        '''
+            Tests that the "scopes" request causes the currently selected
+            thread and frame to be updated. There are no DAP packets that tell
+            lldb-vscode which thread and frame are selected other than the
+            "scopes" request. lldb-vscode will now select the thread and frame
+            for the latest "scopes" request that it receives.
+
+            The LLDB command interpreter needs to have the right thread and
+            frame selected so that commands executed in the debug console act
+            on the right scope. This applies both to the expressions that are
+            evaluated and the lldb commands that start with the backtick
+            character.
+        '''
+        program = self.getBuildArtifact("a.out")
+        self.build_and_launch(program)
+        source = 'main.cpp'
+        breakpoint1_line = line_number(source, '// breakpoint 1')
+        lines = [breakpoint1_line]
+        # Set breakpoint in the thread function so we can step the threads
+        breakpoint_ids = self.set_source_breakpoints(source, lines)
+        self.assertTrue(len(breakpoint_ids) == len(lines),
+                        "expect correct number of breakpoints")
+        self.continue_to_breakpoints(breakpoint_ids)
+        # Cause a "scopes" to be sent for frame zero which should update the
+        # selected thread and frame to frame 0.
+        self.vscode.get_local_variables(frameIndex=0)
+        # Verify frame #0 is selected in the command interpreter by running
+        # the "frame select" command with no frame index which will print the
+        # currently selected frame.
+        self.check_lldb_command("frame select", "frame #0",
+                                "frame 0 is selected")
+
+        # Cause a "scopes" to be sent for frame one which should update the
+        # selected thread and frame to frame 1.
+        self.vscode.get_local_variables(frameIndex=1)
+        # Verify frame #1 is selected in the command interpreter by running
+        # the "frame select" command with no frame index which will print the
+        # currently selected frame.
+
+        self.check_lldb_command("frame select", "frame #1",
+                                "frame 1 is selected")

lldb/test/API/tools/lldb-vscode/console/main.cpp

+
+int multiply(int x, int y) {
+  return x * y; // breakpoint 1
+}
+
+int main(int argc, char const *argv[]) {
+  int result = multiply(argc, 20);
+  return result < 0;
+}

lldb/tools/lldb-vscode/lldb-vscode.cpp

 //===-- lldb-vscode.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
 //
 //===----------------------------------------------------------------------===//
 
g_vsc.debugger.GetCommandInterpreter().HandleCompletionWithDescriptions(
     text.c_str(),
     actual_column,
     0, -1, matches, descriptions);
   size_t count = std::min((uint32_t)50, matches.GetSize());
   targets.reserve(count);
   for (size_t i = 0; i < count; i++) {
     std::string match = matches.GetStringAtIndex(i);
     std::string description = descriptions.GetStringAtIndex(i);
-    
     llvm::json::Object item;
 
     llvm::StringRef match_ref = match;
     for(llvm::StringRef commit_point: {".", "->"}) {
       if (match_ref.contains(commit_point)){
         match_ref = match_ref.rsplit(commit_point).second;
       }
     }
void request_initialize(const llvm::json::Object &request) {
   body.try_emplace("supportsSetVariable", true);
   // The debug adapter supports restarting a frame.
   body.try_emplace("supportsRestartFrame", false);
   // The debug adapter supports the gotoTargetsRequest.
   body.try_emplace("supportsGotoTargetsRequest", false);
   // The debug adapter supports the stepInTargetsRequest.
   body.try_emplace("supportsStepInTargetsRequest", false);
   // We need to improve the current implementation of completions in order to
-  // enable it again. For some context, this is how VSCode works: 
+  // enable it again. For some context, this is how VSCode works:
   // - VSCode sends a completion request whenever chars are added, the user
   //   triggers completion manually via CTRL-space or similar mechanisms, but
   //   not when there's a deletion. Besides, VSCode doesn't let us know which
   //   of these events we are handling. What is more, the use can paste or cut
   //   sections of the text arbitrarily.
   //   https://github.com/microsoft/vscode/issues/89531 tracks part of the
   //   issue just mentioned.
   // This behavior causes many problems with the current way completion is

 //   }]
 // }
 void request_scopes(const llvm::json::Object &request) {
   llvm::json::Object response;
   FillResponse(request, response);
   llvm::json::Object body;
   auto arguments = request.getObject("arguments");
   lldb::SBFrame frame = g_vsc.GetLLDBFrame(*arguments);
+  // As the user selects different stack frames in the GUI, a "scopes" request
+  // will be sent to the DAP. This is the only way we know that the user has
+  // selected a frame in a thread. There are no other notifications that are
+  // sent and VS code doesn't allow multiple frames to show variables
+  // concurrently. If we select the thread and frame as the "scopes" requests
+  // are sent, this allows users to type commands in the debugger console
+  // with a backtick character to run lldb commands and these lldb commands
+  // will now have the right context selected as they are run. If the user
+  // types "`bt" into the debugger console and we had another thread selected
+  // in the LLDB library, we would show the wrong thing to the user. If the
+  // users switches threads with a lldb command like "`thread select 14", the
+  // GUI will not update as there are no "event" notification packets that
+  // allow us to change the currently selected thread or frame in the GUI that
+  // I am aware of.
+  if (frame.IsValid()) {
+    frame.GetThread().GetProcess().SetSelectedThread(frame.GetThread());
+    frame.GetThread().SetSelectedFrame(frame.GetFrameID());
+  }
   g_vsc.variables.Clear();
   g_vsc.variables.Append(frame.GetVariables(true,   // arguments
                                             true,   // locals
                                             false,  // statics
                                             true)); // in_scope_only
   g_vsc.num_locals = g_vsc.variables.GetSize();
   g_vsc.variables.Append(frame.GetVariables(false,  // arguments
                                             false,  // locals