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2562755ee7
The point of writing a macro embedded in a 'do { ... } while (0)'
loop (particularly if the macro has multiple statements or would
otherwise end with an 'if' statement) is so that the macro can be
used as a drop-in statement with the caller supplying the
trailing ';'. Although our coding style frowns on brace-less 'if':
if (cond)
statement;
else
something else;
that is the classic case where failure to use do/while(0) wrapping
would cause the 'else' to pair with any embedded 'if' in the macro
rather than the intended outer 'if'. But conversely, if the macro
includes an embedded ';', then the same brace-less coding style
would now have two statements, making the 'else' a syntax error
rather than pairing with the outer 'if'. Thus, even though our
coding style with required braces is not impacted, ending a macro
with ';' makes our code harder to port to projects that use
brace-less styles.
The change should have no semantic impact. I was not able to
fully compile-test all of the changes (as some of them are
examples of the ugly bit-rotting debug print statements that are
completely elided by default, and I didn't want to recompile
with the necessary -D witnesses - cleaning those up is left as a
bite-sized task for another day); I did, however, audit that for
all files touched, all callers of the changed macros DID supply
a trailing ';' at the callsite, and did not appear to be used
as part of a brace-less conditional.
Found mechanically via: $ git grep -B1 'while (0);' | grep -A1 \\\\
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20171201232433.25193-7-eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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| .. | ||
| macio | ||
| a9scu.c | ||
| applesmc.c | ||
| arm11scu.c | ||
| arm_integrator_debug.c | ||
| arm_l2x0.c | ||
| arm_sysctl.c | ||
| aspeed_scu.c | ||
| aspeed_sdmc.c | ||
| auxbus.c | ||
| bcm2835_mbox.c | ||
| bcm2835_property.c | ||
| bcm2835_rng.c | ||
| cbus.c | ||
| debugexit.c | ||
| eccmemctl.c | ||
| edu.c | ||
| exynos4210_clk.c | ||
| exynos4210_pmu.c | ||
| exynos4210_rng.c | ||
| hyperv_testdev.c | ||
| imx6_ccm.c | ||
| imx6_src.c | ||
| imx25_ccm.c | ||
| imx31_ccm.c | ||
| imx_ccm.c | ||
| ivshmem.c | ||
| Makefile.objs | ||
| max111x.c | ||
| milkymist-hpdmc.c | ||
| milkymist-pfpu.c | ||
| mips_cmgcr.c | ||
| mips_cpc.c | ||
| mips_itu.c | ||
| mmio_interface.c | ||
| mps2-scc.c | ||
| msf2-sysreg.c | ||
| mst_fpga.c | ||
| omap_clk.c | ||
| omap_gpmc.c | ||
| omap_l4.c | ||
| omap_sdrc.c | ||
| omap_tap.c | ||
| pc-testdev.c | ||
| pci-testdev.c | ||
| puv3_pm.c | ||
| pvpanic.c | ||
| sga.c | ||
| slavio_misc.c | ||
| stm32f2xx_syscfg.c | ||
| tmp105.c | ||
| tmp105.h | ||
| tmp421.c | ||
| trace-events | ||
| unimp.c | ||
| vmcoreinfo.c | ||
| zynq_slcr.c | ||
| zynq-xadc.c | ||