gcc-python-pass.c

/*
   Copyright 2011-2013, 2015 David Malcolm <dmalcolm@redhat.com>
   Copyright 2011-2013, 2015 Red Hat, Inc.

   This 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/>.
*/

#include <Python.h>
#include "gcc-python.h"
#include "gcc-python-wrappers.h"
#include "diagnostic.h"
#include "gcc-c-api/gcc-function.h"
#include "gcc-c-api/gcc-location.h"
#if (GCC_VERSION >= 4009)
#include "context.h"
#include "pass_manager.h"
#endif

/*
  Wrapper for GCC's (opt_pass *)
*/

/*
   Ensure we have a unique PyGccPass per pass address (by maintaining a dict)

   For passes defined in Python, this dictionary maps from
   long (struct opt_pass *) to the gcc.Pass wrapper object for that pass

   The references on the right-hand-side keep these wrappers alive
*/
static PyObject *pass_wrapper_cache = NULL;

static bool impl_gate(function *fun)
{
    PyObject *pass_obj;
    PyObject *cfun_obj = NULL;
    PyObject* result_obj;
    int result;
    gcc_location saved_loc = gcc_get_input_location();

    /*
       It appears that current_pass is not set by when gcc (4.7 at least) when
       it invokes gate for an IPA_PASS within execute_ipa_summary_passes
       (in gcc/passes.c), so we don't have a way of figuring out which pass
       we were called on.

       Reported as http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54959
    */
    if (NULL == current_pass) {
        return true;
    }

    assert(current_pass);
    pass_obj = PyGccPass_New(current_pass);
    assert(pass_obj); /* we own a ref at this point */

    if (!PyObject_HasAttrString(pass_obj, "gate")) {
        /* No "gate" method?  Always execute this pass: */
        Py_DECREF(pass_obj);
        return true;
    }

    /* Supply the function, if any */
    if (fun) {
        assert (fun == cfun);
        gcc_function cf = gcc_get_current_function();

        /* Temporarily override input_location to the top of the function: */
        gcc_set_input_location(gcc_function_get_start(cf));
        cfun_obj = PyGccFunction_New(cf);
        if (!cfun_obj) {
            PyGcc_PrintException("Unhandled Python exception raised calling 'gate' method");
            Py_DECREF(pass_obj);
            gcc_set_input_location(saved_loc);
            return false;
        }
        result_obj = PyObject_CallMethod(pass_obj, (char*)"gate", (char*)"O",
                                         cfun_obj, NULL);
    } else {
        result_obj = PyObject_CallMethod(pass_obj, (char*)"gate", NULL);
    }

    Py_XDECREF(cfun_obj);
    Py_DECREF(pass_obj);

    if (!result_obj) {
        PyGcc_PrintException("Unhandled Python exception raised calling 'gate' method");
        gcc_set_input_location(saved_loc);
        return false;
    }

    result = PyObject_IsTrue(result_obj);
    Py_DECREF(result_obj);
    gcc_set_input_location(saved_loc);
    return result;
}

static unsigned int impl_execute(function *fun)
{
    PyObject *pass_obj;
    PyObject *cfun_obj = NULL;
    PyObject* result_obj;
    gcc_location saved_loc = gcc_get_input_location();

    assert(current_pass);
    pass_obj = PyGccPass_New(current_pass);
    assert(pass_obj); /* we own a ref at this point */

    if (fun) {
        assert (fun == cfun);
        gcc_function cf = gcc_get_current_function();

        /* Temporarily override input_location to the top of the function: */
        gcc_set_input_location(gcc_function_get_start(cf));
        cfun_obj = PyGccFunction_New(cf);
        if (!cfun_obj) {
            PyGcc_PrintException("Unhandled Python exception raised calling 'execute' method");
            Py_DECREF(pass_obj);
            gcc_set_input_location(saved_loc);
            return false;
        }
        result_obj = PyObject_CallMethod(pass_obj, (char*)"execute",
                                         (char*)"O", cfun_obj, NULL);
    } else {
        result_obj = PyObject_CallMethod(pass_obj, (char*)"execute", NULL);
    }

    Py_XDECREF(cfun_obj);
    Py_DECREF(pass_obj);

    if (!result_obj) {
        PyGcc_PrintException("Unhandled Python exception raised calling 'execute' method");
        gcc_set_input_location(saved_loc);
        return 0;
    }

    if (result_obj == Py_None) {
        Py_DECREF(result_obj);
        gcc_set_input_location(saved_loc);
        return 0;
    }

#if PY_MAJOR_VERSION < 3
    if (PyInt_Check(result_obj)) {
        long result = PyInt_AS_LONG(result_obj);
        Py_DECREF(result_obj);
        gcc_set_input_location(saved_loc);
        return result;
    }
#endif

    if (PyLong_Check(result_obj)) {
        long result = PyLong_AsLong(result_obj);
        Py_DECREF(result_obj);
        gcc_set_input_location(saved_loc);
        return result;
    }

    PyErr_Format(PyExc_TypeError,
                 "execute returned a non-integer"   \
                 "(type %.200s)",
                 Py_TYPE(result_obj)->tp_name);
    Py_DECREF(result_obj);
    PyGcc_PrintException("Unhandled Python exception raised calling 'execute' method");
    gcc_set_input_location(saved_loc);
    return 0;
}

#if (GCC_VERSION >= 4009)
/*
  GCC 4.9 converted passes to a C++ class hierarchy, with methods for gate
  and execute.
*/

#if (GCC_VERSION >= 5000)
/* GCC 5 added a "fun" param to the "gate" and "execute" vfuncs of
   pass opt_pass.  */
# define PASS_DECLARE_GATE_AND_EXECUTE                                  \
    bool gate (function *fun) { return impl_gate(fun); }                \
    unsigned int execute (function *fun) { return impl_execute(fun); }
#else
/* ...whereas in GCC 4.9 they took no params, with cfun being implied.  */
# define PASS_DECLARE_GATE_AND_EXECUTE                            \
    bool gate () { return impl_gate(cfun); }                      \
    unsigned int execute () { return impl_execute(cfun); }
#endif /* #if (GCC_VERSION >= 5000) */

class PyGccGimplePass : public gimple_opt_pass
{
public:
 PyGccGimplePass(const pass_data& data, gcc::context *ctxt) :
    gimple_opt_pass(data, ctxt)
 {
 }

  PASS_DECLARE_GATE_AND_EXECUTE
  opt_pass *clone() {return this; }
};

class PyGccRtlPass : public rtl_opt_pass
{
public:
  PyGccRtlPass (const pass_data& data, gcc::context *ctxt)
    : rtl_opt_pass (data, ctxt)
  {
  }

  PASS_DECLARE_GATE_AND_EXECUTE
  opt_pass *clone() {return this; }
};

class PyGccIpaPass : public ipa_opt_pass_d
{
public:
  PyGccIpaPass(const pass_data& data, gcc::context *ctxt)
      : ipa_opt_pass_d (data, ctxt,
                        NULL, /* void (*generate_summary) (void), */
                        NULL, /* void (*write_summary) (void), */
                        NULL, /* void (*read_summary) (void), */
                        NULL, /* void (*write_optimization_summary) (void), */
                        NULL, /* void (*read_optimization_summary) (void), */
                        NULL, /* void (*stmt_fixup) (struct cgraph_node *, gimple *), */
                        0, /* unsigned int function_transform_todo_flags_start, */
                        NULL, /* unsigned int (*function_transform) (struct cgraph_node *), */
                        NULL) /* void (*variable_transform) (struct varpool_node *)) */
  {
  }

  PASS_DECLARE_GATE_AND_EXECUTE
  opt_pass *clone() {return this; }
};

class PyGccSimpleIpaPass : public simple_ipa_opt_pass
{
public:
  PyGccSimpleIpaPass(const pass_data& data, gcc::context *ctxt)
    : simple_ipa_opt_pass(data, ctxt)
  {
  }

  PASS_DECLARE_GATE_AND_EXECUTE
  opt_pass *clone() {return this; }
};

#else /* #if (GCC_VERSION >= 4009) */
/*
  Before GCC 4.9, passes were implemented using callback functions.
*/
static bool gate_cb(void)
{
    return impl_gate(cfun);
}

static unsigned int execute_cb(void)
{
    return impl_execute(cfun);
}
#endif /* #else clause of if (GCC_VERSION >= 4009) */

static int
do_pass_init(PyObject *s, PyObject *args, PyObject *kwargs,
             enum opt_pass_type pass_type,
             size_t sizeof_pass)
{
    struct PyGccPass *self = (struct PyGccPass *)s;
    const char *name;
    const char *keywords[] = {"name",
                              NULL};
    struct opt_pass *pass;

    /*
      We need to call _track manually as we're not using PyGccWrapper_New():
    */
    PyGccWrapper_Track(&self->head);

    if (!PyArg_ParseTupleAndKeywords(args, kwargs,
                                     "s:gcc.Pass.__init__", (char**)keywords,
                                     &name)) {
        return -1;
    }

#if (GCC_VERSION >= 4009)
    pass_data pass_data;
    memset(&pass_data, 0, sizeof(pass_data));
    pass_data.type = pass_type;
    pass_data.name = PyGcc_strdup(name);
#if (GCC_VERSION < 5000)
    pass_data.has_gate = true;
    pass_data.has_execute = true;
#endif
    switch (pass_type) {
      case GIMPLE_PASS:
          pass = new PyGccGimplePass (pass_data, g);
          break;
      case RTL_PASS:
          pass = new PyGccRtlPass (pass_data, g);
          break;
      case SIMPLE_IPA_PASS:
          pass = new PyGccSimpleIpaPass (pass_data, g);
          break;
      case IPA_PASS:
          pass = new PyGccIpaPass (pass_data, g);
          break;
      default:
          gcc_unreachable();
    }
#else /* #if (GCC_VERSION >= 4009) */
    pass = (struct opt_pass*)PyMem_Malloc(sizeof_pass);
    if (!pass) {
        return -1;
    }
    memset(pass, 0, sizeof_pass);
    pass->type = pass_type;

    pass->name = PyGcc_strdup(name);
    /* does the name need to be unique?
       mapping from opt_pass ptr to callable?
       (the ID (as a long) is unique)
    */
    if (!pass->name) {
        PyMem_Free(pass);
        return -1;
    }

    pass->gate = gate_cb;
    pass->execute = execute_cb;
#endif /* ending the #else clause of #if (GCC_VERSION >= 4009) */

    if (PyGcc_insert_new_wrapper_into_cache(&pass_wrapper_cache,
                                                 pass,
                                                 s)) {
        return -1;
    }

    self->pass = pass;
    return 0; // FIXME
}

int
PyGccGimplePass_init(PyObject *self, PyObject *args, PyObject *kwds)
{
    return do_pass_init(self, args, kwds,
                        GIMPLE_PASS,
                        sizeof(struct gimple_opt_pass));
}

int
PyGccRtlPass_init(PyObject *self, PyObject *args, PyObject *kwds)
{
    return do_pass_init(self, args, kwds,
                        RTL_PASS,
                        sizeof(struct rtl_opt_pass));
}

int
PyGccSimpleIpaPass_init(PyObject *self, PyObject *args, PyObject *kwds)
{
    return do_pass_init(self, args, kwds,
                        SIMPLE_IPA_PASS,
                        sizeof(struct simple_ipa_opt_pass));
}

int
PyGccIpaPass_init(PyObject *self, PyObject *args, PyObject *kwds)
{
    return do_pass_init(self, args, kwds,
                        IPA_PASS,
                        sizeof(struct ipa_opt_pass_d));
}



PyObject *
PyGccPass_repr(struct PyGccPass *self)
{
     return PyGccString_FromFormat("%s(name='%s')",
                                          Py_TYPE(self)->tp_name,
                                          self->pass->name);
}

#if (GCC_VERSION >= 4009)
static struct dump_file_info *
get_dump_file_info(int phase)
{
    gcc::dump_manager *dumps = g->get_dumps ();
    return dumps->get_dump_file_info (phase);
}
#endif

/* In GCC 4.8, dump_enabled_p changed from acting on one pass to the
   current phase (as of r192773), and dump_phase_enabled_p() was added (as
   of r192692).

   Unfortunately, dump_phase_enabled_p() is static within gcc/dumpfile.c,
   so we use a copy of the 2 lines of relevant code:
*/
static bool
is_dump_enabled(struct opt_pass *pass)
{
#if (GCC_VERSION >= 4008)
    struct dump_file_info *dfi = get_dump_file_info(pass->static_pass_number);
    return dfi->pstate || dfi->alt_state;
#else
    return dump_enabled_p(pass->static_pass_number);
#endif
}

PyObject *
PyGccPass_get_dump_enabled(struct PyGccPass *self, void *closure)
{
    return PyBool_FromLong(is_dump_enabled(self->pass));
}

/* In GCC 4.8, this field became "pstate" */
#if (GCC_VERSION >= 4008)
  #define DFI_STATE(dfi) (dfi)->pstate
#else
  #define DFI_STATE(dfi) (dfi)->state
#endif

int
PyGccPass_set_dump_enabled(struct PyGccPass *self, PyObject *value, void *closure)
{
    struct dump_file_info *dfi = get_dump_file_info (self->pass->static_pass_number);
    assert(dfi);

    int newbool = PyObject_IsTrue(value);
    if (newbool == -1) {
        return -1;
    }

    if (DFI_STATE (dfi) == 0) {
        /* Dumping was disabled: */
        if (newbool) {
            /* Enabling: */
            DFI_STATE (dfi) = -1;
            return 0;
        } else {
            /* No change: */
            return 0;
        }
    } else {
        if (DFI_STATE (dfi) < 0) {
            /* Dumping was enabled but has not yet started */
            if (newbool) {
                /* No change: */
                return 0;
            } else {
                /* Disabling: */
                DFI_STATE (dfi) = 0;
                return 0;
            }
        } else {
            assert(DFI_STATE (dfi) > 0);
            /* Dumping was enabled and has already started */
            if (newbool) {
                /* No change: */
                return 0;
            } else {
                /* Can't disable after it's started: */
                PyErr_SetString(PyExc_RuntimeError,
                                "Can't disable dumping: already started");
                return -1;
            }
        }
    }
}

/* In GCC 4.9, passes moved from being globals to fields of the
   pass_manager.  */
#if (GCC_VERSION >= 4009)
#define GET_PASS_LIST(PASS_NAME) (g->get_passes()->PASS_NAME)
#else
#define GET_PASS_LIST(PASS_NAME) (PASS_NAME)
#endif


PyObject *
PyGccPass_get_roots(PyObject *cls, PyObject *noargs)
{
    /*
      There are 5 "roots" for the pass tree; see gcc/passes.c
    */
    PyObject *result;
    PyObject *passobj;

    result = PyTuple_New(5);
    if (!result) {
        goto error;
    }

#define SET_PASS(IDX, PASS_NAME) \
    passobj = PyGccPass_New(GET_PASS_LIST(PASS_NAME)); \
    if (!passobj) goto error;                  \
    PyTuple_SET_ITEM(result, IDX, passobj);    \
    (void)0;

    SET_PASS(0, all_lowering_passes);
    SET_PASS(1, all_small_ipa_passes);
    SET_PASS(2, all_regular_ipa_passes);
    /* all_late_ipa_passes appeared in r175336 */
    /* r204984 eliminated all_lto_gen_passes */
#if (GCC_VERSION >= 4009)
    SET_PASS(3, all_late_ipa_passes);
#else
    SET_PASS(3, all_lto_gen_passes);
#endif
    SET_PASS(4, all_passes);

    return result;

 error:
    Py_XDECREF(result);
    return NULL;

}

static struct opt_pass *
find_pass_by_name(const char *name, struct opt_pass *pass_list)
{
    struct opt_pass *pass;

    for (pass = pass_list; pass; pass = pass->next)
    {
        if (pass->name && !strcmp (name, pass->name)) {
            /* Found: */
            return pass;
        }

        if (pass->sub) {
            /* Recurse: */
            struct opt_pass *result = find_pass_by_name(name, pass->sub);
            if (result) {
                return result;
            }
        }
    }

    /* Not found: */
    return NULL;
}


PyObject *
PyGccPass_get_by_name(PyObject *cls, PyObject *args, PyObject *kwargs)
{
    const char *name;
    const char *keywords[] = {"name",
                              NULL};
    struct opt_pass *result;

    if (!PyArg_ParseTupleAndKeywords(args, kwargs,
                                     "s:get_by_name", (char**)keywords,
                                     &name)) {
        return NULL;
    }

#define SEARCH_WITHIN_LIST(PASS_LIST) \
    result = find_pass_by_name(name, (GET_PASS_LIST(PASS_LIST))); \
    if (result) {                                    \
        return PyGccPass_New(result); \
    }

    SEARCH_WITHIN_LIST(all_lowering_passes);
    SEARCH_WITHIN_LIST(all_small_ipa_passes);
    SEARCH_WITHIN_LIST(all_regular_ipa_passes);
    /* all_late_ipa_passes appeared in r175336 */
    /* r204984 eliminated all_lto_gen_passes */
#if (GCC_VERSION >= 4009)
    SEARCH_WITHIN_LIST(all_late_ipa_passes);
#else
    SEARCH_WITHIN_LIST(all_lto_gen_passes);
#endif
    SEARCH_WITHIN_LIST(all_passes);

    /* Not found: */
    PyErr_Format(PyExc_ValueError, "pass named '%s' not found", name);
    return NULL;
}

static PyObject *
impl_register(struct PyGccPass *self, PyObject *args, PyObject *kwargs,
              enum pass_positioning_ops pos_op, const char *arg_format)
{
    struct register_pass_info rpi;
    const char *keywords[] = {"name",
                              "instance_number",
                              NULL};

    rpi.pass = self->pass;
    rpi.pos_op = pos_op;
    rpi.ref_pass_instance_number = 0;

    if (!PyArg_ParseTupleAndKeywords(args, kwargs,
                                     arg_format, (char**)keywords,
                                     &rpi.reference_pass_name,
                                     &rpi.ref_pass_instance_number)) {
        return NULL;
    }

    /* (Failures lead to a fatal error) */
    register_pass (&rpi);

    Py_RETURN_NONE;
}

PyObject *
PyGccPass_register_before(struct PyGccPass *self, PyObject *args, PyObject *kwargs)
{
    return impl_register(self, args, kwargs,
                         PASS_POS_INSERT_BEFORE,
                         "s|i:register_before");
}

PyObject *
PyGccPass_register_after(struct PyGccPass *self, PyObject *args, PyObject *kwargs)
{
    return impl_register(self, args, kwargs,
                         PASS_POS_INSERT_AFTER,
                         "s|i:register_after");
}

PyObject *
PyGccPass_replace(struct PyGccPass *self, PyObject *args, PyObject *kwargs)
{
    return impl_register(self, args, kwargs,
                         PASS_POS_REPLACE,
                         "s|i:replace");
}

static PyGccWrapperTypeObject *
get_type_for_pass_type(enum opt_pass_type pt)
{
    switch (pt) {
    default: assert(0);

    case GIMPLE_PASS:
	return &PyGccGimplePass_TypeObj;

    case RTL_PASS:
	return &PyGccRtlPass_TypeObj;

    case SIMPLE_IPA_PASS:
	return &PyGccSimpleIpaPass_TypeObj;

    case IPA_PASS:
	return &PyGccIpaPass_TypeObj;
    }
};


static PyObject *
real_make_pass_wrapper(void *p)
{
    struct opt_pass *pass = (struct opt_pass *)p;
    PyGccWrapperTypeObject *type_obj;
    struct PyGccPass *pass_obj = NULL;

    if (NULL == pass) {
	Py_RETURN_NONE;
    }

    type_obj = get_type_for_pass_type(pass->type);

    pass_obj = PyGccWrapper_New(struct PyGccPass, type_obj);
    if (!pass_obj) {
        goto error;
    }

    pass_obj->pass = pass;
    /* FIXME: do we need to do something for the GCC GC? */

    return (PyObject*)pass_obj;
      
error:
    return NULL;
}

void
PyGcc_WrtpMarkForPyGccPass(PyGccPass *wrapper)
{
    /*
      This function is empty: struct opt_pass does not have a GTY()
      and any (struct opt_pass*) is either statically-allocated, or
      allocated by us within do_pass_init using PyMem_Malloc
    */
}

PyObject *
PyGccPass_New(struct opt_pass *pass)
{
    return PyGcc_LazilyCreateWrapper(&pass_wrapper_cache,
					    pass,
					    real_make_pass_wrapper);
}

/*
  PEP-7  
Local variables:
c-basic-offset: 4
indent-tabs-mode: nil
End:
*/