1 files changed, 93 insertions, 0 deletions
diff --git a/gdb/python/lib/gdb/dap/bt.py b/gdb/python/lib/gdb/dap/bt.py
new file mode 100644
index 0000000..990ab13
--- /dev/null
+++ b/gdb/python/lib/gdb/dap/bt.py
@@ -0,0 +1,93 @@
+# Copyright 2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import gdb
+import os
+
+from .frames import frame_id
+from .server import request, capability
+from .startup import send_gdb_with_response, in_gdb_thread
+from .state import set_thread
+
+
+# Helper function to safely get the name of a frame as a string.
+@in_gdb_thread
+def _frame_name(frame):
+    name = frame.name()
+    if name is None:
+        name = "???"
+    return name
+
+
+# Helper function to get a frame's SAL without an error.
+@in_gdb_thread
+def _safe_sal(frame):
+    try:
+        return frame.find_sal()
+    except gdb.error:
+        return None
+
+
+# Helper function to compute a stack trace.
+@in_gdb_thread
+def _backtrace(thread_id, levels, startFrame):
+    set_thread(thread_id)
+    frames = []
+    current_number = 0
+    # FIXME could invoke frame filters here.
+    try:
+        current_frame = gdb.newest_frame()
+    except gdb.error:
+        current_frame = None
+    # Note that we always iterate over all frames, which is lame, but
+    # seemingly necessary to support the totalFrames response.
+    # FIXME maybe the mildly mysterious note about "monotonically
+    # increasing totalFrames values" would let us fix this.
+    while current_frame is not None:
+        # This condition handles the startFrame==0 case as well.
+        if current_number >= startFrame and (levels == 0 or len(frames) < levels):
+            newframe = {
+                "id": frame_id(current_frame),
+                "name": _frame_name(current_frame),
+                # This must always be supplied, but we will set it
+                # correctly later if that is possible.
+                "line": 0,
+                # GDB doesn't support columns.
+                "column": 0,
+                "instructionPointerReference": hex(current_frame.pc()),
+            }
+            sal = _safe_sal(current_frame)
+            if sal is not None:
+                newframe["source"] = {
+                    "name": os.path.basename(sal.symtab.filename),
+                    "path": sal.symtab.filename,
+                    # We probably don't need this but it doesn't hurt
+                    # to be explicit.
+                    "sourceReference": 0,
+                }
+                newframe["line"] = sal.line
+            frames.append(newframe)
+        current_number = current_number + 1
+        current_frame = current_frame.older()
+    return {
+        "stackFrames": frames,
+        "totalFrames": current_number,
+    }
+
+
+@request("stackTrace")
+@capability("supportsDelayedStackTraceLoading")
+def stacktrace(*, levels=0, startFrame=0, threadId, **extra):
+    return send_gdb_with_response(lambda: _backtrace(threadId, levels, startFrame))