Re: [python] Allow explicit locations in breakpoints.

[Phil Muldoon <pmuldoon@redhat.com>]

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On 07/12/17 14:54, Simon Marchi wrote:
> On 2017-12-07 07:15, Phil Muldoon wrote:
>> On 07/12/17 10:02, Phil Muldoon wrote:
>>> On 23/11/17 22:17, Simon Marchi wrote:
>>>> On 2017-11-17 06:02 AM, Phil Muldoon wrote:

>> Phil
> 
> Thanks for the git-am format, it's usually easier to apply.  However, I can't seem to find the right baseline.  Which commit did you base this on?  If it is old-ish, would it be possible for you to rebase it to current master?
> 
> Thanks,
> 
> Simon

Apologies, my github branch was more behind master than I at first
thought. I've attached the update patch.

Cheers,

Phil


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From: Phil Muldoon <pmuldoon@redhat.com>
Date: Thu, 7 Dec 2017 15:05:51 +0000
Subject: [PATCH] Implement explicit locations for Python breakpoints.
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit

This introduces several new keywords to the bppy_init constructor.
The spec parameter is now optional but mutually exclusive to the
explicit keywords source, label, function and line.

gdb/ChangeLog

2017-12-07  Phil Muldoon  <pmuldoon@redhat.com>

       * python/py-breakpoint.c (bppy_init): Use string_to_event_location
       over basic location code. Implement explicit location keywords.
       (bppy_init_validate_args): New function.
       * NEWS: Document Python explicit breakpoint locations.

doc/ChangeLog

2017-12-07  Phil Muldoon  <pmuldoon@redhat.com>

       * python.texi (Breakpoints In Python): Add text relating
       to allowed explicit locations and keywords in gdb.Breakpoints.

testsuite/ChangeLog

2017-12-07  Phil Muldoon  <pmuldoon@redhat.com>

       * gdb.python/py-breakpoint.exp (test_bkpt_explicit_loc): Add new
       tests for explicit locations.
---
 gdb/NEWS                                   |   4 +
 gdb/doc/python.texi                        |  41 +++++----
 gdb/python/py-breakpoint.c                 | 134 ++++++++++++++++++++++++++---
 gdb/testsuite/gdb.python/py-breakpoint.c   |   2 +-
 gdb/testsuite/gdb.python/py-breakpoint.exp |  80 +++++++++++++++++
 5 files changed, 228 insertions(+), 33 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 2262b259a8..72b4057f4d 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -115,6 +115,10 @@
      command allows the setting of a large number of breakpoints via a
      regex pattern in Python.  See the manual for further details.
 
+  ** Python breakpoints can now accept explicit locations.  See the
+     manual for a further description of this feature.
+
+
 * New features in the GDB remote stub, GDBserver
 
   ** GDBserver is now able to start inferior processes with a
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index f411f60d7e..28a7a1a9f5 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -4878,27 +4878,30 @@ represented as Python @code{Long} values.
 Python code can manipulate breakpoints via the @code{gdb.Breakpoint}
 class.
 
-@defun Breakpoint.__init__ (spec @r{[}, type @r{[}, wp_class @r{[},internal @r{[},temporary@r{]]]]})
+@defun Breakpoint.__init__ (spec @r{[}, type @r{[}, wp_class @r{[}, internal @r{[}, temporary @r{]}, source @r{]}, function @r{]}, label @r{]}, line @r{]]]]]]]]})
 Create a new breakpoint according to @var{spec}, which is a string
 naming the location of the breakpoint, or an expression that defines a
-watchpoint.  The contents can be any location recognized by the
-@code{break} command, or in the case of a watchpoint, by the
-@code{watch} command.  The optional @var{type} denotes the breakpoint
-to create from the types defined later in this chapter.  This argument
-can be either @code{gdb.BP_BREAKPOINT} or @code{gdb.BP_WATCHPOINT}; it
-defaults to @code{gdb.BP_BREAKPOINT}.  The optional @var{internal}
-argument allows the breakpoint to become invisible to the user.  The
-breakpoint will neither be reported when created, nor will it be
-listed in the output from @code{info breakpoints} (but will be listed
-with the @code{maint info breakpoints} command).  The optional
-@var{temporary} argument makes the breakpoint a temporary breakpoint.
-Temporary breakpoints are deleted after they have been hit.  Any
-further access to the Python breakpoint after it has been hit will
-result in a runtime error (as that breakpoint has now been
-automatically deleted).  The optional @var{wp_class} argument defines
-the class of watchpoint to create, if @var{type} is
-@code{gdb.BP_WATCHPOINT}.  If a watchpoint class is not provided, it
-is assumed to be a @code{gdb.WP_WRITE} class.
+watchpoint. The contents can be any location recognized by the
+@code{break} command or, in the case of a watchpoint, by the
+@code{watch} command.  Alternatively, create a new a explicit location
+breakpoint (@pxref{Explicit Locations}) according to the
+specifications contained in the key words @var{source},
+@var{function}, @var{label} and @var{line}.  The optional @var{type}
+denotes the breakpoint to create from the types defined later in this
+chapter.  This argument can be either @code{gdb.BP_BREAKPOINT} or
+@code{gdb.BP_WATCHPOINT}; it defaults to @code{gdb.BP_BREAKPOINT}.
+The optional @var{internal} argument allows the breakpoint to become
+invisible to the user.  The breakpoint will neither be reported when
+created, nor will it be listed in the output from @code{info
+breakpoints} (but will be listed with the @code{maint info
+breakpoints} command).  The optional @var{temporary} argument makes
+the breakpoint a temporary breakpoint.  Temporary breakpoints are
+deleted after they have been hit.  Any further access to the Python
+breakpoint after it has been hit will result in a runtime error (as
+that breakpoint has now been automatically deleted).  The optional
+@var{wp_class} argument defines the class of watchpoint to create, if
+@var{type} is @code{gdb.BP_WATCHPOINT}.  If a watchpoint class is not
+provided, it is assumed to be a @code{gdb.WP_WRITE} class.
 @end defun
 
 The available types are represented by constants defined in the @code{gdb}
diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
index 2574683ed4..f865317ab3 100644
--- a/gdb/python/py-breakpoint.c
+++ b/gdb/python/py-breakpoint.c
@@ -32,6 +32,7 @@
 #include "language.h"
 #include "location.h"
 #include "py-event.h"
+#include "linespec.h"
 
 /* Number of live breakpoints.  */
 static int bppy_live;
@@ -631,25 +632,104 @@ bppy_get_ignore_count (PyObject *self, void *closure)
   return PyInt_FromLong (self_bp->bp->ignore_count);
 }
 
+/* Internal function to validate the Python parameters/keywords
+   provided to bppy_init.  */
+
+static int
+bppy_init_validate_args (const char *spec, char *source,
+			 char *function, char *label,
+			 char *line, enum bptype type)
+{
+  /* If spec is defined, ensure that none of the explicit location
+     keywords are also defined.  */
+  if (spec != NULL)
+    {
+      if (source != NULL || function != NULL || label != NULL || line != NULL)
+	{
+	  PyErr_SetString (PyExc_RuntimeError,
+			   _("Breakpoints specified with spec cannot "
+			     "have source, function, label or line defined."));
+	  return -1;
+	}
+    }
+  else
+    {
+      /* If spec isn't defined, ensure that the user is not trying to
+	 define a watchpoint with an explicit location.  */
+      if (type == bp_watchpoint)
+	{
+	  PyErr_SetString (PyExc_RuntimeError,
+			   _("Watchpoints cannot be set by explicit "
+			     "location parameters."));
+	  return -1;
+	}
+      else
+	{
+	  /* Otherwise, ensure some explicit locations are defined.  */
+	  if (source == NULL && function == NULL && label == NULL
+	      && line == NULL)
+	    {
+	      PyErr_SetString (PyExc_RuntimeError,
+			       _("Neither spec nor explicit location set."));
+	      return -1;
+	    }
+	  /* Finally, if source is specified, ensure that line, label
+	     or function are specified too.  */
+	  if (source != NULL && function == NULL && label == NULL
+	      && line == NULL)
+	    {
+	      PyErr_SetString (PyExc_RuntimeError,
+			       _("Specifying a source must also include a "
+				 "line, label or function."));
+	      return -1;
+	    }
+	}
+    }
+  return 1;
+}
+
 /* Python function to create a new breakpoint.  */
 static int
 bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
 {
   static const char *keywords[] = { "spec", "type", "wp_class", "internal",
-				    "temporary", NULL };
-  const char *spec;
-  int type = bp_breakpoint;
+				    "temporary","source", "function",
+				    "label", "line", NULL };
+  const char *spec = NULL;
+  enum bptype type = bp_breakpoint;
   int access_type = hw_write;
   PyObject *internal = NULL;
   PyObject *temporary = NULL;
+  PyObject *lineobj = NULL;;
   int internal_bp = 0;
   int temporary_bp = 0;
+  gdb::unique_xmalloc_ptr<char> line;
+  char *label = NULL;
+  char *source = NULL;
+  char *function = NULL;
 
-  if (!gdb_PyArg_ParseTupleAndKeywords (args, kwargs, "s|iiOO", keywords,
+  if (!gdb_PyArg_ParseTupleAndKeywords (args, kwargs, "|siiOOsssO", keywords,
 					&spec, &type, &access_type,
-					&internal, &temporary))
+					&internal,
+					&temporary, &source,
+					&function, &label, &lineobj))
     return -1;
 
+
+  if (lineobj != NULL)
+    {
+      if (PyInt_Check (lineobj))
+	line.reset (xstrprintf ("%ld", PyInt_AsLong (lineobj)));
+      else if (PyString_Check (lineobj))
+	line = python_string_to_host_string (lineobj);
+      else
+	{
+	  PyErr_SetString (PyExc_RuntimeError,
+			   _("Line keyword should be an integer or a string. "));
+	  return -1;
+	}
+    }
+
   if (internal)
     {
       internal_bp = PyObject_IsTrue (internal);
@@ -664,23 +744,47 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
 	return -1;
     }
 
+  if (bppy_init_validate_args (spec, source, function, label, line.get (),
+			       type) == -1)
+    return -1;
+
   bppy_pending_object = (gdbpy_breakpoint_object *) self;
   bppy_pending_object->number = -1;
   bppy_pending_object->bp = NULL;
 
   TRY
     {
-      gdb::unique_xmalloc_ptr<char>
-	copy_holder (xstrdup (skip_spaces (spec)));
-      const char *copy = copy_holder.get ();
-
       switch (type)
 	{
 	case bp_breakpoint:
 	  {
-	    event_location_up location
-	      = string_to_event_location_basic (&copy, current_language,
-						symbol_name_match_type::WILD);
+	    event_location_up location;
+
+	    if (spec != NULL)
+	      {
+		gdb::unique_xmalloc_ptr<char>
+		  copy_holder (xstrdup (skip_spaces (spec)));
+		const char *copy = copy_holder.get ();
+
+		location  = string_to_event_location (&copy,
+						      current_language);
+	      }
+	    else
+	      {
+		struct explicit_location explicit_loc;
+
+		initialize_explicit_location (&explicit_loc);
+		explicit_loc.source_filename = source;
+		explicit_loc.function_name = function;
+		explicit_loc.label_name = label;
+
+		if (line != NULL)
+		  explicit_loc.line_offset =
+		    linespec_parse_line_offset (line.get ());
+
+		location = new_explicit_location (&explicit_loc);
+	      }
+
 	    create_breakpoint (python_gdbarch,
 			       location.get (), NULL, -1, NULL,
 			       0,
@@ -691,8 +795,12 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
 			       0, 1, internal_bp, 0);
 	    break;
 	  }
-        case bp_watchpoint:
+	case bp_watchpoint:
 	  {
+	    gdb::unique_xmalloc_ptr<char>
+	      copy_holder (xstrdup (skip_spaces (spec)));
+	    char *copy = copy_holder.get ();
+
 	    if (access_type == hw_write)
 	      watch_command_wrapper (copy, 0, internal_bp);
 	    else if (access_type == hw_access)
diff --git a/gdb/testsuite/gdb.python/py-breakpoint.c b/gdb/testsuite/gdb.python/py-breakpoint.c
index df6163e53a..562cab35f7 100644
--- a/gdb/testsuite/gdb.python/py-breakpoint.c
+++ b/gdb/testsuite/gdb.python/py-breakpoint.c
@@ -24,7 +24,7 @@ int multiply (int i)
 
 int add (int i)
 {
-  return i + i; 
+  return i + i;  /* Break at function add.  */
 }
 
 
diff --git a/gdb/testsuite/gdb.python/py-breakpoint.exp b/gdb/testsuite/gdb.python/py-breakpoint.exp
index 6c39f13696..e89b9b8446 100644
--- a/gdb/testsuite/gdb.python/py-breakpoint.exp
+++ b/gdb/testsuite/gdb.python/py-breakpoint.exp
@@ -531,6 +531,85 @@ proc_with_prefix test_bkpt_events {} {
     check_last_event breakpoint_deleted
 }
 
+proc test_bkpt_explicit_loc {} {
+    global srcfile testfile
+
+    with_test_prefix test_bkpt_invisible {
+	# Start with a fresh gdb.
+	clean_restart ${testfile}
+
+	if ![runto_main] then {
+	    fail "cannot run to main."
+	    return 0
+	}
+
+	delete_breakpoints
+
+	set bp_location1 [gdb_get_line_number "Break at multiply."]
+	set bp_location2 [gdb_get_line_number "Break at add."]
+
+	gdb_py_test_silent_cmd "python bp1 = gdb.Breakpoint (line=$bp_location1)" \
+	    "set explicit breakpoint by line" 0
+	gdb_continue_to_breakpoint "break at multiply for explicit line" \
+	    ".*Break at multiply.*"
+
+	gdb_py_test_silent_cmd "python bp1 = gdb.Breakpoint (line=\"+1\")" \
+	    "set explicit breakpoint by relative line" 0
+	gdb_continue_to_breakpoint "break at add for relative line" \
+	    ".*Break at add.*"
+
+	delete_breakpoints
+	gdb_py_test_silent_cmd "python bp1 = gdb.Breakpoint (line=\"-1\")" \
+	    "set explicit breakpoint by relative negative line" 0
+	gdb_continue_to_breakpoint "break at multiply for negative line" \
+	    ".*Break at multiply.*"
+
+	delete_breakpoints
+	gdb_test "python bp1 = gdb.Breakpoint (line=bp1)" \
+	    "RuntimeError: Line keyword should be an integer or a string.*" \
+	    "set explicit breakpoint by invalid line type"
+
+	delete_breakpoints
+	gdb_py_test_silent_cmd "python bp1 = gdb.Breakpoint (function=\"add\")" \
+	    "set explicit breakpoint by function" 0
+	gdb_continue_to_breakpoint "break at function add for function" \
+	    ".*Break at function add.*"
+
+	delete_breakpoints
+	gdb_py_test_silent_cmd "python bp1 = gdb.Breakpoint (source=\"$srcfile\", function=\"add\")" \
+	    "set explicit breakpoint by source file and function" 0
+	gdb_continue_to_breakpoint "break at function add for source and function" \
+	    ".*Break at function add.*"
+
+	delete_breakpoints
+	gdb_py_test_silent_cmd "python bp1 = gdb.Breakpoint (source=\"$srcfile\", line=\"$bp_location2\")" \
+	    "set explicit breakpoint by source file and line number" 0
+	gdb_continue_to_breakpoint "break at add for source and line" \
+	    ".*Break at add.*"
+
+	delete_breakpoints
+	gdb_py_test_silent_cmd "python bp1 = gdb.Breakpoint (\"-source $srcfile -line $bp_location2\")" \
+	    "set explicit breakpoint by source file and line number in spec" 0
+	gdb_continue_to_breakpoint "break at add for source and line in spec" \
+	    ".*Break at add.*"
+
+	delete_breakpoints
+	gdb_test "python bp1 = gdb.Breakpoint (source=\"$srcfile\")" \
+	    "RuntimeError: Specifying a source must also include a line, label or function.*" \
+	    "set invalid explicit breakpoint by source only"
+
+	gdb_test "python bp1 = gdb.Breakpoint (source=\"foo.c\", line=\"5\")" \
+	    "No source file named foo.*" \
+	    "set invalid explicit breakpoint by missing source and line"
+	gdb_test "python bp1 = gdb.Breakpoint (source=\"$srcfile\", line=\"900\")" \
+	    "No line 900 in file \"$srcfile\".*" \
+	    "set invalid explicit breakpoint by source and invalid line"
+	gdb_test "python bp1 = gdb.Breakpoint (function=\"blah\")" \
+	    "Function \"blah\" not defined.*" \
+	    "set invalid explicit breakpoint by missing function"
+    }
+}
+
 test_bkpt_basic
 test_bkpt_deletion
 test_bkpt_cond_and_cmds
@@ -542,3 +621,4 @@ test_bkpt_temporary
 test_bkpt_address
 test_bkpt_pending
 test_bkpt_events
+test_bkpt_explicit_loc
-- 
2.14.3