Implement DAP conditional breakpoints

I realized that I had only implemented DAP breakpoint conditions for
exception breakpoints, and not other kinds of breakpoints.  This patch
corrects the oversight.

3 files changed, 144 insertions, 16 deletions

diff --git a/gdb/python/lib/gdb/dap/breakpoint.py b/gdb/python/lib/gdb/dap/breakpoint.py
index ad01933..20e65aa 100644
--- a/gdb/python/lib/gdb/dap/breakpoint.py
+++ b/gdb/python/lib/gdb/dap/breakpoint.py
@@ -63,6 +63,14 @@ def breakpoint_descriptor(bp):
         }
 
 
+# Extract entries from a hash table and return a list of them.  Each
+# entry is a string.  If a key of that name appears in the hash table,
+# it is removed and pushed on the result list; if it does not appear,
+# None is pushed on the list.
+def _remove_entries(table, *names):
+    return [table.pop(name, None) for name in names]
+
+
 # Helper function to set some breakpoints according to a list of
 # specifications and a callback function to do the work of creating
 # the breakpoint.
@@ -78,11 +86,20 @@ def _set_breakpoints_callback(kind, specs, creator):
     result = []
     for spec in specs:
         keyspec = frozenset(spec.items())
+
+        (condition, hit_condition) = _remove_entries(spec, "condition", "hitCondition")
+
         if keyspec in saved_map:
             bp = saved_map.pop(keyspec)
         else:
             # FIXME handle exceptions here
             bp = creator(**spec)
+
+        if condition is not None:
+            bp.condition = condition
+        if hit_condition is not None:
+            bp.ignore_count = hit_condition
+
         breakpoint_map[kind][keyspec] = bp
         result.append(breakpoint_descriptor(bp))
     # Delete any breakpoints that were not reused.
@@ -98,9 +115,22 @@ def _set_breakpoints(kind, specs):
     return _set_breakpoints_callback(kind, specs, gdb.Breakpoint)
 
 
+# Turn a DAP SourceBreakpoint, FunctionBreakpoint, or
+# InstructionBreakpoint into a "spec" that is used by
+# _set_breakpoints.  SPEC is a dictionary of parameters that is used
+# as the base of the result; it is modified in place.
+def _basic_spec(bp_info, spec):
+    for name in ("condition", "hitCondition"):
+        if name in bp_info:
+            spec[name] = bp_info[name]
+    return spec
+
+
 # FIXME we do not specify a type for 'source'.
 # FIXME 'breakpoints' is really a list[SourceBreakpoint].
 @request("setBreakpoints")
+@capability("supportsHitConditionalBreakpoints")
+@capability("supportsConditionalBreakpoints")
 def set_breakpoint(*, source, breakpoints: Sequence = (), **args):
     if "path" not in source:
         result = []
@@ -108,10 +138,13 @@ def set_breakpoint(*, source, breakpoints: Sequence = (), **args):
         specs = []
         for obj in breakpoints:
             specs.append(
-                {
-                    "source": source["path"],
-                    "line": obj["line"],
-                }
+                _basic_spec(
+                    obj,
+                    {
+                        "source": source["path"],
+                        "line": obj["line"],
+                    },
+                )
             )
         # Be sure to include the path in the key, so that we only
         # clear out breakpoints coming from this same source.
@@ -128,9 +161,12 @@ def set_fn_breakpoint(*, breakpoints: Sequence, **args):
     specs = []
     for bp in breakpoints:
         specs.append(
-            {
-                "function": bp["name"],
-            }
+            _basic_spec(
+                bp,
+                {
+                    "function": bp["name"],
+                },
+            )
         )
     result = send_gdb_with_response(lambda: _set_breakpoints("function", specs))
     return {
@@ -151,9 +187,12 @@ def set_insn_breakpoints(
         if offset is not None:
             val = val + " + " + str(offset)
         specs.append(
-            {
-                "spec": val,
-            }
+            _basic_spec(
+                bp,
+                {
+                    "spec": val,
+                },
+            )
         )
     result = send_gdb_with_response(lambda: _set_breakpoints("instruction", specs))
     return {
@@ -162,16 +201,14 @@ def set_insn_breakpoints(
 
 
 @in_gdb_thread
-def _catch_exception(filterId, condition=None, **args):
+def _catch_exception(filterId, **args):
     if filterId == "assert":
-        args = ["-catch-assert"]
+        cmd = "-catch-assert"
     elif filterId == "exception":
-        args = ["-catch-exception"]
+        cmd = "-catch-exception"
     else:
         raise Exception(f"Invalid exception filterID: {filterId}")
-    if condition is not None:
-        args.extend(["-c", condition])
-    result = gdb.execute_mi(*args)
+    result = gdb.execute_mi(cmd)
     # A little lame that there's no more direct way.
     for bp in gdb.breakpoints():
         if bp.number == result["bkptno"]:
diff --git a/gdb/testsuite/gdb.dap/cond-bp.c b/gdb/testsuite/gdb.dap/cond-bp.c
new file mode 100644
index 0000000..535b15d
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/cond-bp.c
@@ -0,0 +1,26 @@
+/* Copyright 2023 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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/>.  */
+
+int
+main ()
+{
+  int acc = 0, i, j;
+  for (i = 0; i < 5; ++i)
+    for (j = 0; j < 5; ++j)
+      acc += i + j;		/* STOP */
+  return acc;
+}
diff --git a/gdb/testsuite/gdb.dap/cond-bp.exp b/gdb/testsuite/gdb.dap/cond-bp.exp
new file mode 100644
index 0000000..376db4b
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/cond-bp.exp
@@ -0,0 +1,65 @@
+# Copyright 2023 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/>.
+
+# Test DAP breakpoint conditions.
+
+require allow_dap_tests
+
+load_lib dap-support.exp
+
+standard_testfile
+
+if {[build_executable ${testfile}.exp $testfile] == -1} {
+    return
+}
+
+if {[dap_launch $testfile] == ""} {
+    return
+}
+
+set line [gdb_get_line_number "STOP"]
+set obj [dap_check_request_and_response "set conditional breakpoint" \
+	     setBreakpoints \
+	     [format {o source [o path [%s]] \
+			  breakpoints [a [o line [i %d] \
+					      condition [s "i == 3"] \
+					      hitCondition [i 3]]]} \
+		  [list s $srcfile] $line]]
+set fn_bpno [dap_get_breakpoint_number $obj]
+
+dap_check_request_and_response "start inferior" configurationDone
+
+dap_wait_for_event_and_check "stopped at function breakpoint" stopped \
+    "body reason" breakpoint \
+    "body hitBreakpointIds" $fn_bpno
+
+set bt [lindex [dap_check_request_and_response "backtrace" stackTrace \
+		    {o threadId [i 1]}] \
+	    0]
+set frame_id [dict get [lindex [dict get $bt body stackFrames] 0] id]
+
+set obj [dap_check_request_and_response "evaluate i" \
+	     evaluate \
+	     [format {o expression [s i] frameId [i %s]} $frame_id]]
+dap_match_values "value of i" [lindex $obj 0] \
+    "body result" 3
+
+set obj [dap_check_request_and_response "evaluate j" \
+	     evaluate \
+	     [format {o expression [s j] frameId [i %s]} $frame_id]]
+dap_match_values "value of j" [lindex $obj 0] \
+    "body result" 3
+
+dap_shutdown