mirror of https://gitee.com/openkylin/qemu.git
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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|---|---|---|
| .. | ||
| alpha | ||
| cris | ||
| lm32 | ||
| mips | ||
| openrisc | ||
| xtensa | ||
| Makefile | ||
| README | ||
| hello-arm.c | ||
| hello-i386.c | ||
| hello-mips.c | ||
| linux-test.c | ||
| pi_10.com | ||
| runcom.c | ||
| sha1.c | ||
| test-arm-iwmmxt.s | ||
| test-i386-code16.S | ||
| test-i386-fprem.c | ||
| test-i386-muldiv.h | ||
| test-i386-shift.h | ||
| test-i386-ssse3.c | ||
| test-i386-vm86.S | ||
| test-i386.c | ||
| test-i386.h | ||
| test-mmap.c | ||
| test_path.c | ||
| testthread.c | ||
README
This directory contains various interesting programs for regression testing. The target "make test" runs the programs and, if applicable, runs "diff" to detect mismatches between output on the host and output on QEMU. i386 ==== test-i386 --------- This program executes most of the 16 bit and 32 bit x86 instructions and generates a text output, for comparison with the output obtained with a real CPU or another emulator. The Linux system call modify_ldt() is used to create x86 selectors to test some 16 bit addressing and 32 bit with segmentation cases. The Linux system call vm86() is used to test vm86 emulation. Various exceptions are raised to test most of the x86 user space exception reporting. linux-test ---------- This program tests various Linux system calls. It is used to verify that the system call parameters are correctly converted between target and host CPUs. test-i386-fprem --------------- runcom ------ test-mmap --------- sha1 ---- hello-i386 ---------- ARM === hello-arm --------- test-arm-iwmmxt --------------- MIPS ==== hello-mips ---------- hello-mipsel ------------ CRIS ==== The testsuite for CRIS is in tests/tcg/cris. You can run it with "make test-cris". LM32 ==== The testsuite for LM32 is in tests/tcg/cris. You can run it with "make test-lm32".