[RFC,v2,13/21] gdb/python: allow instantiation of gdb.Compunit from Python

Message ID 20241121124714.419946-14-jan.vrany@labware.com
State New
Headers
Series Add Python "JIT" API |

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Commit Message

Jan Vraný Nov. 21, 2024, 12:47 p.m. UTC
  This commit adds code to allow user extension to instantiate
gdb.Compunit. This is a step towards a Python support for dynamically
generated code (JIT) in GDB.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
---
 gdb/doc/python.texi                      | 18 ++++-
 gdb/python/py-compunit.c                 | 97 +++++++++++++++++++++++-
 gdb/python/py-objfile.c                  | 12 +++
 gdb/python/python-internal.h             |  1 +
 gdb/testsuite/gdb.python/py-compunit.exp | 42 +++++++++-
 5 files changed, 167 insertions(+), 3 deletions(-)
  

Comments

Eli Zaretskii Nov. 21, 2024, 1:40 p.m. UTC | #1
> From: Jan Vrany <jan.vrany@labware.com>
> CC: Jan Vrany <jan.vrany@labware.com>,
> 	Eli Zaretskii <eliz@gnu.org>
> Date: Thu, 21 Nov 2024 12:47:06 +0000
> 
> This commit adds code to allow user extension to instantiate
> gdb.Compunit. This is a step towards a Python support for dynamically
> generated code (JIT) in GDB.
> 
> Reviewed-By: Eli Zaretskii <eliz@gnu.org>
> ---
>  gdb/doc/python.texi                      | 18 ++++-
>  gdb/python/py-compunit.c                 | 97 +++++++++++++++++++++++-
>  gdb/python/py-objfile.c                  | 12 +++
>  gdb/python/python-internal.h             |  1 +
>  gdb/testsuite/gdb.python/py-compunit.exp | 42 +++++++++-
>  5 files changed, 167 insertions(+), 3 deletions(-)

OK for the documentation part, thanks.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
  

Patch

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index f48803d08b4..115d5f04165 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -6551,7 +6551,7 @@  that objfile.  @xref{Objfiles In Python}.
 A @code{gdb.Compunit} object has the following attributes:
 
 @defvar Compunit.objfile
-The compunits' backing object file.  @xref{Objfiles In Python}.
+The compunit's backing object file.  @xref{Objfiles In Python}.
 This attribute is not writable.
 @end defvar
 
@@ -6570,6 +6570,22 @@  The list of symbol tables associated with this compunit.
 
 A @code{gdb.Compunit} object has the following methods:
 
+@defun Compunit.__init__ (filename, objfile, start, end @r{[}, capacity @r{]})
+Create a new compunit with given @var{filename} in given @var{objfile}
+(@pxref{Objfiles In Python}).  The newly created compunit has an empty global
+block and empty static block (@pxref{Blocks In Python}).
+
+The @var{start} and @var{end} arguments specifies the start and end address
+of compunit's global and static blocks.  It must not overlap with any existing
+compunit belonging to the same program space
+(@pxref{Progspaces In Python}).
+
+The optional @var{capacity} argument sets the initial capacity of the
+internal block vector.  More blocks than @var{capacity} can still be added
+to the compunit however.  If not specified, defaults to 8 blocks (including
+global and static blocks).
+@end defun
+
 @defun Compunit.is_valid ()
 Returns @code{True} if the @code{gdb.Compunit} object is valid,
 @code{False} if not.  A @code{gdb.Compunit} object can become invalid if
diff --git a/gdb/python/py-compunit.c b/gdb/python/py-compunit.c
index 829746cc92d..c7e89643abc 100644
--- a/gdb/python/py-compunit.c
+++ b/gdb/python/py-compunit.c
@@ -17,6 +17,7 @@ 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
+#include <algorithm>
 #include "charset.h"
 #include "symtab.h"
 #include "source.h"
@@ -217,6 +218,100 @@  set_compunit (compunit_object *obj, struct compunit_symtab *compunit)
     obj->next = nullptr;
 }
 
+/* Object initializer; creates a new compunit.
+
+   Use: __init__(FILENAME, OBJFILE, START, END [, CAPACITY]).  */
+
+static int
+cupy_init (PyObject *zelf, PyObject *args, PyObject *kw)
+{
+  struct compunit_object *self = (struct compunit_object*) zelf;
+
+  if (self->compunit)
+    {
+      PyErr_Format (PyExc_RuntimeError,
+		    _("Compunit object already initialized."));
+      return -1;
+    }
+
+  static const char *keywords[] = { "filename", "objfile", "start", "end",
+				    "capacity", nullptr };
+  const char *filename;
+  PyObject *objf_obj = nullptr;
+  uint64_t start = 0;
+  uint64_t end = 0;
+  uint64_t capacity = 8;
+
+
+  if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "sOKK|K", keywords,
+					&filename, &objf_obj, &start, &end,
+					&capacity))
+    return -1;
+
+  auto objf = objfile_object_to_objfile (objf_obj);
+  if (! objf)
+    {
+      PyErr_Format (PyExc_TypeError,
+		    _("The objfile argument is not valid gdb.Objfile object"));
+      return -1;
+    }
+
+  /* Check that start-end range is valid.  */
+  if (! (start <= end))
+    {
+      PyErr_Format (PyExc_ValueError,
+		    _("The start argument must be less or equal to the end "
+		      "argument"));
+      return -1;
+
+    }
+
+  /* Check that to-be created compunits' global block does not overlap
+     with existing compunit.  */
+
+  for (struct objfile *of : objf->pspace ()->objfiles_safe ())
+    {
+      for (compunit_symtab *cu : of->compunits ())
+	{
+	  global_block *gb = cu->blockvector ()->global_block ();
+	  if (std::max (start, gb->start ()) < std::min(end, gb->end ()))
+	    {
+	      PyErr_Format (PyExc_ValueError,
+		    _("The start-end range overlaps with existing compunit"));
+	      return -1;
+	    }
+	}
+    }
+
+  blockvector *bv = allocate_blockvector (&objf->objfile_obstack,
+					  FIRST_LOCAL_BLOCK, capacity);
+  compunit_symtab *cu = allocate_compunit_symtab (objf, filename);
+  cu->set_dirname (nullptr);
+  cu->set_blockvector (bv);
+
+  /* Allocate global block. */
+  global_block *gb = new (&objf->objfile_obstack) global_block ();
+  gb->set_multidict (mdict_create_linear_expandable (language_minimal));
+  gb->set_start ((CORE_ADDR) start);
+  gb->set_end ((CORE_ADDR) end);
+  gb->set_compunit (cu);
+  bv->set_block (GLOBAL_BLOCK, gb);
+
+  /* Allocate static block.  */
+  struct block *sb = new (&objf->objfile_obstack) block ();
+  sb->set_multidict (mdict_create_linear_expandable (language_minimal));
+  sb->set_start ((CORE_ADDR) start);
+  sb->set_end ((CORE_ADDR) end);
+  sb->set_superblock (gb);
+  bv->set_block (STATIC_BLOCK, sb);
+
+  add_compunit_symtab_to_objfile (cu);
+
+  set_compunit(self, cu);
+
+  return 0;
+}
+
 /* Return a new reference to gdb.Compunit Python object representing
    COMPUNIT.  Return NULL and set the Python error on failure.  */
 gdbpy_ref<>
@@ -313,7 +408,7 @@  PyTypeObject compunit_object_type = {
   0,				  /* tp_descr_get */
   0,				  /* tp_descr_set */
   0,				  /* tp_dictoffset */
-  0,				  /* tp_init */
+  cupy_init,                      /* tp_init */
   0,				  /* tp_alloc */
   PyType_GenericNew		  /* tp_new */
 };
diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index f8b29ae1f47..21f46260e74 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -824,6 +824,18 @@  objfile_to_objfile_object (struct objfile *objfile)
   return gdbpy_ref<>::new_reference (result);
 }
 
+/* Returns the struct objfile value corresponding to the given Python
+   objfile object OBJ.  Returns NULL if OBJ is not an objfile object.  */
+
+struct objfile *
+objfile_object_to_objfile (PyObject *obj)
+{
+  if (! PyObject_TypeCheck (obj, &objfile_object_type))
+    return nullptr;
+
+  return ((objfile_object *)obj)->objfile;
+}
+
 /* This function remove any dynamic objfiles left over when the
    inferior exits.  */
 
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index a5bcfedf79b..88432e04f47 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -575,6 +575,7 @@  frame_info_ptr frame_object_to_frame_info (PyObject *frame_obj);
 struct gdbarch *arch_object_to_gdbarch (PyObject *obj);
 struct compunit_symtab *compunit_object_to_compunit (PyObject *obj);
 inferior *inferior_object_to_inferior(PyObject *obj);
+struct objfile *objfile_object_to_objfile(PyObject *obj);
 
 extern PyObject *gdbpy_execute_mi_command (PyObject *self, PyObject *args,
 					   PyObject *kw);
diff --git a/gdb/testsuite/gdb.python/py-compunit.exp b/gdb/testsuite/gdb.python/py-compunit.exp
index 450cd6c9f1b..cf9197988d7 100644
--- a/gdb/testsuite/gdb.python/py-compunit.exp
+++ b/gdb/testsuite/gdb.python/py-compunit.exp
@@ -54,9 +54,49 @@  gdb_test "python print (objfile.compunits()\[0\].symtabs)" \
     "Compunit symtabs return a sequence of gdb.Symtab"
 
 
+# Test creation of compunits
+gdb_py_test_silent_cmd "python cu = gdb.Compunit(\"compunit1\", objfile, 200, 300)" \
+    "Create compunit1" 1
+gdb_test "python print(cu)" \
+    "<gdb\.Compunit object at .*>" \
+    "Print created compunit1"
+gdb_test "python print(cu in objfile.compunits())" \
+    "True" \
+    "Test compunit1 is in objfile.compunits()"
+gdb_test "python print(cu.global_block().start)" \
+    "0" \
+    "Test compunit1.global_block().start is 0"
+gdb_test "python print(cu.global_block().end)" \
+    "0" \
+    "Test compunit1.global_block().end is 0"
+gdb_test "python print(cu.static_block().start)" \
+    "0" \
+    "Test compunit1.static_block().start is 0"
+gdb_test "python print(cu.static_block().end)" \
+    "0" \
+    "Test compunit1.static_block().end is 0"
+
+gdb_py_test_silent_cmd "python cu2 = gdb.Compunit(\"dynamic2\", objfile, 400, 500, 24)" \
+    "Create compunit2 with capacity fo 24 blocks" 1
+
+gdb_test "python cu3 = gdb.Compunit(\"dynamic3\", gdb, 600, 700)" \
+    "TypeError.*:.*" \
+    "Create compunit3 passing non-objfile"
+
+gdb_test "python cu4 = gdb.Compunit(\"dynamic4\", objfile, 900, 800)" \
+    "ValueError.*:.*" \
+    "Create compunit4 passing invalid global block range"
+
+gdb_test "python cu5 = gdb.Compunit(\"dynamic5\", objfile, 225, 325)" \
+    "ValueError.*:.*" \
+    "Create compunit4 passing overlapping global block range"
+
+
 gdb_unload "unload 1"
 
 gdb_test "python print (objfile.is_valid())" "False" \
 "Get objfile validity after unload"
 gdb_test "python print (objfile.compunits())" "RuntimeError.*: Objfile no longer exists.*" \
-"Get objfile compunits after unload"
\ No newline at end of file
+"Get objfile compunits after unload"
+gdb_py_test_silent_cmd "python cu6 = gdb.Compunit(\"dynamic6\", objfile)" \
+    "Create compunit4 passing invalid objfile" 1
\ No newline at end of file