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	|  668f62ec62 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> | ||
|---|---|---|
| .. | ||
| asi.h | ||
| cc_helper.c | ||
| cpu-param.h | ||
| cpu-qom.h | ||
| cpu.c | ||
| cpu.h | ||
| fop_helper.c | ||
| gdbstub.c | ||
| helper.c | ||
| helper.h | ||
| int32_helper.c | ||
| int64_helper.c | ||
| ldst_helper.c | ||
| machine.c | ||
| Makefile.objs | ||
| mmu_helper.c | ||
| monitor.c | ||
| trace-events | ||
| translate.c | ||
| vis_helper.c | ||
| win_helper.c | ||