qemu/hw/cpu/core.c
Markus Armbruster 668f62ec62 error: Eliminate error_propagate() with Coccinelle, part 1
When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.  Convert

    if (!foo(..., &err)) {
        ...
        error_propagate(errp, err);
        ...
        return ...
    }

to

    if (!foo(..., errp)) {
        ...
        ...
        return ...
    }

where nothing else needs @err.  Coccinelle script:

    @rule1 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
         if (
    (
    -        fun(args, &err, args2)
    +        fun(args, errp, args2)
    |
    -        !fun(args, &err, args2)
    +        !fun(args, errp, args2)
    |
    -        fun(args, &err, args2) op c1
    +        fun(args, errp, args2) op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    )
         }

    @rule2 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    expression var;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
    -    var = fun(args, &err, args2);
    +    var = fun(args, errp, args2);
         ... when != err
         if (
    (
             var
    |
             !var
    |
             var op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    |
             return var;
    )
         }

    @depends on rule1 || rule2@
    identifier err;
    @@
    -    Error *err = NULL;
         ... when != err

Not exactly elegant, I'm afraid.

The "when != lbl:" is necessary to avoid transforming

         if (fun(args, &err)) {
             goto out
         }
         ...
     out:
         error_propagate(errp, err);

even though other paths to label out still need the error_propagate().
For an actual example, see sclp_realize().

Without the "when strict", Coccinelle transforms vfio_msix_setup(),
incorrectly.  I don't know what exactly "when strict" does, only that
it helps here.

The match of return is narrower than what I want, but I can't figure
out how to express "return where the operand doesn't use @err".  For
an example where it's too narrow, see vfio_intx_enable().

Silently fails to convert hw/arm/armsse.c, because Coccinelle gets
confused by ARMSSE being used both as typedef and function-like macro
there.  Converted manually.

Line breaks tidied up manually.  One nested declaration of @local_err
deleted manually.  Preexisting unwanted blank line dropped in
hw/riscv/sifive_e.c.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-35-armbru@redhat.com>
2020-07-10 15:18:08 +02:00

100 lines
2.6 KiB
C

/*
* CPU core abstract device
*
* Copyright (C) 2016 Bharata B Rao <bharata@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "hw/cpu/core.h"
#include "qapi/visitor.h"
#include "qemu/module.h"
#include "qapi/error.h"
#include "sysemu/cpus.h"
#include "hw/boards.h"
static void core_prop_get_core_id(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
CPUCore *core = CPU_CORE(obj);
int64_t value = core->core_id;
visit_type_int(v, name, &value, errp);
}
static void core_prop_set_core_id(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
CPUCore *core = CPU_CORE(obj);
int64_t value;
if (!visit_type_int(v, name, &value, errp)) {
return;
}
if (value < 0) {
error_setg(errp, "Invalid core id %"PRId64, value);
return;
}
core->core_id = value;
}
static void core_prop_get_nr_threads(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
CPUCore *core = CPU_CORE(obj);
int64_t value = core->nr_threads;
visit_type_int(v, name, &value, errp);
}
static void core_prop_set_nr_threads(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
CPUCore *core = CPU_CORE(obj);
int64_t value;
if (!visit_type_int(v, name, &value, errp)) {
return;
}
core->nr_threads = value;
}
static void cpu_core_instance_init(Object *obj)
{
MachineState *ms = MACHINE(qdev_get_machine());
CPUCore *core = CPU_CORE(obj);
object_property_add(obj, "core-id", "int", core_prop_get_core_id,
core_prop_set_core_id, NULL, NULL);
object_property_add(obj, "nr-threads", "int", core_prop_get_nr_threads,
core_prop_set_nr_threads, NULL, NULL);
core->nr_threads = ms->smp.threads;
}
static void cpu_core_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
set_bit(DEVICE_CATEGORY_CPU, dc->categories);
}
static const TypeInfo cpu_core_type_info = {
.name = TYPE_CPU_CORE,
.parent = TYPE_DEVICE,
.abstract = true,
.class_init = cpu_core_class_init,
.instance_size = sizeof(CPUCore),
.instance_init = cpu_core_instance_init,
};
static void cpu_core_register_types(void)
{
type_register_static(&cpu_core_type_info);
}
type_init(cpu_core_register_types)