Add [opt] suffix to optimized stack frame in lldb-vscode

[yinghuitan]

Summary

To help user identify optimized code This diff adds a "[opt]" suffix to
optimized stack frames in lldb-vscode. This provides consistent experience
as command line lldb.

It also adds a new "optimized" attribute to DAP stack frame object so that
it is easy to identify from telemetry than parsing trailing "[opt]".

[clayborg]

lldb/tools/lldb-vscode/JSONUtils.cpp

754–767

No need to test if the function is valid, the SBFunction::IsValid() does this already for us and will return false if it isn't valid.

758

This will crash if the function name is NULL, so we should guard against this.

762

We should probably get the function name with "const char *func_name = frame.GetFunctionName();" before the entire "if (is_optimized)" and use it here, and above

[clayborg]

lldb/tools/lldb-vscode/JSONUtils.cpp

754–767

I meant to say "the SBFunction::GetIsOptimized()" does this already and will return false if it isn't valid

[yinghuitan]

lldb/tools/lldb-vscode/JSONUtils.cpp

762

Thanks, seems we have this potential crash in existing code already. I will fix it.

[yinghuitan]

Address review comments

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

+CXX_SOURCES := main.cpp
+CXXFLAGS_EXTRAS := -O3 -glldb
+include Makefile.rules

lldb/test/API/tools/lldb-vscode/optimized/TestVSCode_optimized.py

+"""
+Test lldb-vscode variables/stackTrace request for optimized code
+"""
+
+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_optimized(lldbvscode_testcase.VSCodeTestCaseBase):
+    mydir = TestBase.compute_mydir(__file__)
+
+    @skipIfWindows
+    @skipIfRemote
+    def test_stack_frame_name(self):
+        ''' Test optimized frame has special name suffix.
+        '''
+        program = self.getBuildArtifact("a.out")
+        self.build_and_launch(program)
+        source = 'main.cpp'
+        breakpoint_line = line_number(source, '// breakpoint 1')
+        lines = [breakpoint_line]
+        breakpoint_ids = self.set_source_breakpoints(source, lines)
+        self.assertEqual(len(breakpoint_ids), len(lines),
+                        "expect correct number of breakpoints")
+        self.continue_to_breakpoints(breakpoint_ids)
+        leaf_frame = self.vscode.get_stackFrame(frameIndex=0)
+        self.assertTrue(leaf_frame['name'].endswith(' [opt]'))
+        parent_frame = self.vscode.get_stackFrame(frameIndex=1)
+        self.assertTrue(parent_frame['name'].endswith(' [opt]'))

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

+#include <stdio.h>
+#include <string>
+
+int foo(int x, int y) {
+  printf("Got input %d, %d\n", x, y);
+  return x + y + 3; // breakpoint 1
+}
+
+int main(int argc, char const *argv[]) {
+  int optimized = argc > 1 ? std::stoi(argv[1]) : 0;
+
+  printf("argc: %d, optimized: %d\n", argc, optimized);
+  int result = foo(argc, 20);
+  printf("result: %d\n", result); // breakpoint 2
+  return 0;
+}

lldb/tools/lldb-vscode/JSONUtils.cpp

 //     }
 //   },
 //   "required": [ "id", "name", "line", "column" ]
 // }
 llvm::json::Value CreateStackFrame(lldb::SBFrame &frame) {
   llvm::json::Object object;
   int64_t frame_id = MakeVSCodeFrameID(frame);
   object.try_emplace("id", frame_id);
-  EmplaceSafeString(object, "name", frame.GetFunctionName());
+
+  std::string frame_name;
+  const char *func_name = frame.GetFunctionName();
+  if (func_name)
+    frame_name = func_name;
+  else
+    frame_name = "<unknown>";
+  bool is_optimized = frame.GetFunction().GetIsOptimized();
+  if (is_optimized)
+    frame_name += " [opt]";
+  EmplaceSafeString(object, "name", frame_name);
+  object.try_emplace("optimized", is_optimized);
+
   int64_t disasm_line = 0;
   object.try_emplace("source", CreateSource(frame, disasm_line));
 
   auto line_entry = frame.GetLineEntry();
   if (disasm_line > 0) {
     object.try_emplace("line", disasm_line);
   } else {
     auto line = line_entry.GetLine();
     if (line == UINT32_MAX)