From 668f62ec621e4e2919fb7d4caa5d805764c5852d Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Tue, 7 Jul 2020 18:06:02 +0200 Subject: 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 Reviewed-by: Eric Blake Message-Id: <20200707160613.848843-35-armbru@redhat.com> --- hw/misc/macio/pmu.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'hw/misc/macio/pmu.c') diff --git a/hw/misc/macio/pmu.c b/hw/misc/macio/pmu.c index 42ba963d8c..09022995ad 100644 --- a/hw/misc/macio/pmu.c +++ b/hw/misc/macio/pmu.c @@ -735,13 +735,11 @@ static void pmu_reset(DeviceState *dev) static void pmu_realize(DeviceState *dev, Error **errp) { PMUState *s = VIA_PMU(dev); - Error *err = NULL; SysBusDevice *sbd; ADBBusState *adb_bus = &s->adb_bus; struct tm tm; - if (!sysbus_realize(SYS_BUS_DEVICE(&s->mos6522_pmu), &err)) { - error_propagate(errp, err); + if (!sysbus_realize(SYS_BUS_DEVICE(&s->mos6522_pmu), errp)) { return; } -- cgit v1.2.3