Add Frame.read_register to Python API
Commit Message
Thanks.
Here it is again:
The ability to read registers is needed to use Frame Filter API to
display the frames created by JIT compilers.
gdb/ChangeLog:
2014-08-29 Sasha Smundak <asmundak@google.com>
* python/py-frame.c (frapy_read_register): New function.
gdb/doc/ChangeLog
2014-08-26 Sasha Smundak <asmundak@google.com>
* python.texi (Frames in Python): Add read_register description.
gdb/testsuite/ChangeLog:
2014-08-26 Sasha Smundak <asmundak@google.com>
* gdb.python/py-frame.exp: Test Frame.read_register.
Comments
On Fri, Aug 29, 2014 at 4:32 PM, Sasha Smundak <asmundak@google.com> wrote:
> Thanks.
> Here it is again:
>
>
> The ability to read registers is needed to use Frame Filter API to
> display the frames created by JIT compilers.
>
> gdb/ChangeLog:
>
> 2014-08-29 Sasha Smundak <asmundak@google.com>
>
>
> * python/py-frame.c (frapy_read_register): New function.
>
> gdb/doc/ChangeLog
>
>
> 2014-08-26 Sasha Smundak <asmundak@google.com>
>
> * python.texi (Frames in Python): Add read_register description.
>
> gdb/testsuite/ChangeLog:
>
>
> 2014-08-26 Sasha Smundak <asmundak@google.com>
>
> * gdb.python/py-frame.exp: Test Frame.read_register.
LGTM.
On Fri, Aug 29, 2014 at 4:36 PM, Doug Evans <dje@google.com> wrote:
> On Fri, Aug 29, 2014 at 4:32 PM, Sasha Smundak <asmundak@google.com> wrote:
>> Thanks.
>> Here it is again:
>>
>>
>> The ability to read registers is needed to use Frame Filter API to
>> display the frames created by JIT compilers.
>>
>> gdb/ChangeLog:
>>
>> 2014-08-29 Sasha Smundak <asmundak@google.com>
>>
>>
>> * python/py-frame.c (frapy_read_register): New function.
>>
>> gdb/doc/ChangeLog
>>
>>
>> 2014-08-26 Sasha Smundak <asmundak@google.com>
>>
>> * python.texi (Frames in Python): Add read_register description.
>>
>> gdb/testsuite/ChangeLog:
>>
>>
>> 2014-08-26 Sasha Smundak <asmundak@google.com>
>>
>> * gdb.python/py-frame.exp: Test Frame.read_register.
>
> LGTM.
Hi.
fyi, I've committed this.
Thanks!
@@ -3,6 +3,9 @@
*** Changes since GDB 7.8
+* Python Scripting
+ You can now access frame registers from Python scripts.
+
* On resume, GDB now always passes the signal the program had stopped
for to the thread the signal was sent to, even if the user changed
threads before resuming. Previously GDB would often (but not
@@ -3589,6 +3589,13 @@ Return the frame's symtab and line object.
@xref{Symbol Tables In Python}.
@end defun
+@defun Frame.read_register (register)
+Return the value of @var{register} in this frame. The @var{register}
+argument must be a string (e.g., @code{'sp'} or @code{'rax'}).
+Returns a @code{Gdb.Value} object. Throws an exception if @var{register}
+does not exist.
+@end defun
+
@defun Frame.read_var (variable @r{[}, block@r{]})
Return the value of @var{variable} in this frame. If the optional
argument @var{block} is provided, search for the variable from that
@@ -28,6 +28,7 @@
#include "python-internal.h"
#include "symfile.h"
#include "objfiles.h"
+#include "user-regs.h"
typedef struct {
PyObject_HEAD
@@ -235,6 +236,40 @@ frapy_pc (PyObject *self, PyObject *args)
return gdb_py_long_from_ulongest (pc);
}
+/* Implementation of gdb.Frame.read_register (self, register) -> gdb.Value.
+ Returns the value of a register in this frame. */
+
+static PyObject *
+frapy_read_register (PyObject *self, PyObject *args)
+{
+ volatile struct gdb_exception except;
+ const char *regnum_str;
+ struct value *val = NULL;
+
+ if (!PyArg_ParseTuple (args, "s", ®num_str))
+ return NULL;
+
+ TRY_CATCH (except, RETURN_MASK_ALL)
+ {
+ struct frame_info *frame;
+ int regnum;
+
+ FRAPY_REQUIRE_VALID (self, frame);
+
+ regnum = user_reg_map_name_to_regnum (get_frame_arch (frame),
+ regnum_str,
+ strlen (regnum_str));
+ if (regnum >= 0)
+ val = value_of_register (regnum, frame);
+
+ if (val == NULL)
+ PyErr_SetString (PyExc_ValueError, _("Unknown register."));
+ }
+ GDB_PY_HANDLE_EXCEPTION (except);
+
+ return val == NULL ? NULL : value_to_value_object (val);
+}
+
/* Implementation of gdb.Frame.block (self) -> gdb.Block.
Returns the frame's code block. */
@@ -674,6 +709,9 @@ Return the reason why it's not possible to find frames older than this." },
{ "pc", frapy_pc, METH_NOARGS,
"pc () -> Long.\n\
Return the frame's resume address." },
+ { "read_register", frapy_read_register, METH_VARARGS,
+ "read_register (register_name) -> gdb.Value\n\
+Return the value of the register in the frame." },
{ "block", frapy_block, METH_NOARGS,
"block () -> gdb.Block.\n\
Return the frame's code block." },
@@ -94,3 +94,20 @@ gdb_test "python print ('result = %s' % f0.read_var ('variable_which_surely_does
gdb_test "python print ('result = %s' % f0.read_var ('a'))" " = 1" "test Frame.read_var - success"
gdb_test "python print ('result = %s' % (gdb.selected_frame () == f1))" " = True" "test gdb.selected_frame"
+
+# Can read SP register.
+gdb_test "python print ('result = %s' % (gdb.selected_frame ().read_register ('sp') == gdb.parse_and_eval ('\$sp')))" \
+ " = True" \
+ "test Frame.read_register(sp)"
+
+# PC value obtained via read_register is as expected.
+gdb_test "python print ('result = %s' % (f0.read_register('pc') == f0.pc()))" \
+ " = True" \
+ "test Frame.read_register(pc)"
+
+# On x86-64, PC is in $rip register.
+if {[istarget x86_64-*]} {
+ gdb_test "python print ('result = %s' % (f0.read_register('pc') == f0.read_register('rip')))" \
+ " = True" \
+ "test Frame.read_register(rip)"
+}