qemu/target/sparc
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
..
asi.h Clean up ill-advised or unusual header guards 2019-05-13 08:58:55 +02:00
cc_helper.c
cpu-param.h tcg: Split out target/arch/cpu-param.h 2019-06-10 07:03:34 -07:00
cpu-qom.h cpu: Use DeviceClass reset instead of a special CPUClass reset 2020-03-17 19:48:10 -04:00
cpu.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
cpu.h gdbstub: extend GByteArray to read register helpers 2020-03-17 17:38:38 +00:00
fop_helper.c softfloat: Name compare relation enum 2020-05-19 08:41:45 -07:00
gdbstub.c gdbstub: extend GByteArray to read register helpers 2020-03-17 17:38:38 +00:00
helper.c Clean up inclusion of sysemu/sysemu.h 2019-08-16 13:31:53 +02:00
helper.h target-sparc: implement UA2005 GL register 2017-01-18 22:03:44 +01:00
int32_helper.c target/sparc/int32_helper: Extract and use excp_name_str() 2020-06-09 09:21:10 +02:00
int64_helper.c sparc: embed sparc_def_t into CPUSPARCState 2017-09-01 11:54:24 -03:00
ldst_helper.c tcg: Search includes from the project root source directory 2020-01-15 15:13:10 -10:00
machine.c Include hw/boards.h a bit less 2019-08-16 13:31:53 +02:00
Makefile.objs
mmu_helper.c target/sparc: Remove unused ldl_phys from dump_mmu() 2019-09-17 12:01:00 +01:00
monitor.c hmp: Move hmp.h to include/monitor/ 2019-07-02 07:19:45 +02:00
trace-events trace-events: Shorten file names in comments 2019-03-22 16:18:07 +00:00
translate.c target/sparc: Translate flushw opcode 2020-06-29 12:59:50 +02:00
vis_helper.c
win_helper.c sparc: embed sparc_def_t into CPUSPARCState 2017-09-01 11:54:24 -03:00