From patchwork Wed Jun 11 23:52:45 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Smundak X-Patchwork-Id: 1456 Received: (qmail 1752 invoked by alias); 11 Jun 2014 23:52:49 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 1740 invoked by uid 89); 11 Jun 2014 23:52:48 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.7 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_LOW, RP_MATCHES_RCVD, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-oa0-f51.google.com Received: from mail-oa0-f51.google.com (HELO mail-oa0-f51.google.com) (209.85.219.51) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Wed, 11 Jun 2014 23:52:47 +0000 Received: by mail-oa0-f51.google.com with SMTP id j17so551371oag.24 for ; Wed, 11 Jun 2014 16:52:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=PFwhd+t770JKh57tGNWQ8dkBGpvGora6FLy3QF1ZHVg=; b=G1CtWxpk5XlanjrSm8k5kU3A4TZzBunDo5owQNtH8Xqcjt7AYpMrokZZGytBXWAGTy s1cEjEEQuNpKL/zzRmL8ccioBNxsIxuYGvtbEj9PktIGqDfumC/U6pWYgU/Y4QCLfINw D/s9Ey6behTjmADjbLkhymwWndYRl8UvKM6NRcte2VyS28ULiKtTGXABpwN6pXNyGVg1 m38YwQvJh+CQQg4GtPJ/4EtEVELozlFTk6wp/1nGDjw918sQ/fn71M7R1LrVJs84N3PA noooPg0QqYvQYfV074JjLWv7bwjETAWtJ64sskKdJu+PzbNy06s61HrLfuRwlK7pQekj ZYcA== X-Gm-Message-State: ALoCoQkbT0ARB2Xgu6KALQp4yH3xTHhZOaa/HxmQmDT6l+KuA0WCB+cHrwQNtX6pEerHdhee0f64 MIME-Version: 1.0 X-Received: by 10.60.33.102 with SMTP id q6mr8224908oei.59.1402530765466; Wed, 11 Jun 2014 16:52:45 -0700 (PDT) Received: by 10.182.144.133 with HTTP; Wed, 11 Jun 2014 16:52:45 -0700 (PDT) In-Reply-To: <87ioo7uuqm.fsf@fleche.redhat.com> References: <83oay128ca.fsf@gnu.org> <87ioo7uuqm.fsf@fleche.redhat.com> Date: Wed, 11 Jun 2014 16:52:45 -0700 Message-ID: Subject: Re: [PATCH] Add Frame.read_register to Python API From: Alexander Smundak To: Tom Tromey Cc: Eli Zaretskii , gdb-patches > Alexander> def __init__(self, fobj): > Alexander> super(InlinedFrameDecorator, self).__init__(fobj) > Alexander> + self.fobj = fobj > > Alexander> def function(self): > Alexander> - frame = fobj.inferior_frame() > Alexander> + frame = self.fobj.inferior_frame() > Alexander> name = str(frame.name()) > > I think this is a nice fix but it seems unrelated to the patch at hand. > > Alexander> @defun Frame.find_sal () > Alexander> -Return the frame's symtab and line object. > Alexander> +Return the frame's @code{gdb.Symtab_and_line} object. > > Likewise. Should I mail these two as a single patch or as two separate patches? > Alexander> + FRAPY_REQUIRE_VALID (self, frame); > Alexander> + if (!PyArg_ParseTuple (args, "i", ®num)) > Alexander> + { > Alexander> + const char *regnum_str; > Alexander> + PyErr_Clear(); /* Clear PyArg_ParseTuple failure above. */ > Alexander> + if (PyArg_ParseTuple (args, "s", ®num_str)) > Alexander> + { > Alexander> + regnum = user_reg_map_name_to_regnum (get_frame_arch (frame), > Alexander> + regnum_str, > Alexander> + strlen (regnum_str)); > Alexander> + } > Alexander> + } > > I tend to think this would be clearer if the arguments were only parsed > once and then explicit type checks were applied to the resulting object. Did that, and then started doubting whether it is really necessary to read a register by its (very arch-specific) number. The new version supports reading the register by the name. Another change is that it now throws an exception if the name is wrong. > Alexander> +# On x86-64, PC is register 16. > Alexander> +gdb_test "python print ('result = %s' % ((f0.architecture().name() != 'i386:x86-64') or f0.read_register('pc') == f0.read_register(16)))" \ > Alexander> + "True" \ > Alexander> + "test Frame.read_register(regnum)" > > A test that is arch-specific needs to be conditionalized somehow. IMHO it's borderline arch-specific -- it is runnable on any platform, although it will not be testing much on any but x86-64. There hasn't been any arch-specific tests for Python so far, so I am not sure what to do. Here's the new version (style violations have been addressed, too): The ability to read registers is needed to use Frame Filter API to display the frames created by JIT compilers. gdb/Changelog 2014-06-11 Sasha Smundak * python/py-frame.c (frapy_read_register): New function. 2014-06-11 Sasha Smundak * python.texi (Frames in Python): Add read_register description. 2014-06-11 Sasha Smundak * gdb.python/py-frame.exp: Test Frame.read_register. diff --git a/gdb/NEWS b/gdb/NEWS index 1397e8b..3db458b 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -3,6 +3,9 @@ *** Changes since GDB 7.7 +* Python Scripting + You can now access frame registers from Python scripts. + * New command line options -D data-directory diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi index 4688783..3cb6bf8 100644 --- a/gdb/doc/python.texi +++ b/gdb/doc/python.texi @@ -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 diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c index 77077d3..73bffb1 100644 --- a/gdb/python/py-frame.c +++ b/gdb/python/py-frame.c @@ -28,6 +28,7 @@ #include "python-internal.h" #include "symfile.h" #include "objfiles.h" +#include "user-regs.h" typedef struct { PyObject_HEAD @@ -235,6 +236,39 @@ 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) +{ + struct frame_info *frame; + volatile struct gdb_exception except; + int regnum = -1; + struct value *val = NULL; + const char *regnum_str; + + if (!PyArg_ParseTuple (args, "s", ®num_str)) + return NULL; + + TRY_CATCH (except, RETURN_MASK_ALL) + { + 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 +708,9 @@ 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) -> 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." }, diff --git a/gdb/testsuite/gdb.python/py-frame.exp b/gdb/testsuite/gdb.python/py-frame.exp index 3517824..9eeebba 100644 --- a/gdb/testsuite/gdb.python/py-frame.exp +++ b/gdb/testsuite/gdb.python/py-frame.exp @@ -94,3 +94,16 @@ 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' % f0.read_register('sp'))" \ + " = 0x\[0-9a-fA-F\]+" \ + "test Frame.read_register(fp)" +# PC value obtained via read_register is as expected. +gdb_test "python print ('result = %s' % (f0.read_register('pc').cast(gdb.lookup_type('unsigned long')) == f0.pc()))" \ + "True" \ + "test Frame.read_register(pc)" +# On x86-64, PC is in $rip register. +gdb_test "python print ('result = %s' % ((f0.architecture().name() != 'i386:x86-64') or f0.read_register('pc') == f0.read_register('rip')))" \ + "True" \ + "test Frame.read_register(regnum)"