unicorn/qemu
Eric Blake 12dabf0640
qapi: Don't box struct branch of alternate
There's no reason to do two malloc's for an alternate type visiting
a QAPI struct; let's just inline the struct directly as the C union
branch of the struct.

Surprisingly, no clients were actually using the struct member prior
to this patch outside of the testsuite; an earlier patch in the series
added some testsuite coverage to make the effect of this patch more
obvious.

In qapi.py, c_type() gains a new is_unboxed flag to control when we
are emitting a C struct unboxed within the context of an outer
struct (different from our other two modes of usage with no flags
for normal local variable declarations, and with is_param for adding
'const' in a parameter list). I don't know if there is any more
pythonic way of collapsing the two flags into a single parameter,
as we never have a caller setting both flags at once.

Ultimately, we want to also unbox branches for QAPI unions, but as
that touches a lot more client code, it is better as separate
patches. But since unions and alternates share gen_variants(), I
had to hack in a way to test if we are visiting an alternate type
for setting the is_unboxed flag: look for a non-object branch.
This works because alternates have at least two branches, with at
most one object branch, while unions have only object branches.
The hack will go away in a later patch.

The generated code difference to qapi-types.h is relatively small:

| struct BlockdevRef {
| QType type;
| union { /* union tag is @type */
| void *data;
|- BlockdevOptions *definition;
|+ BlockdevOptions definition;
| char *reference;
| } u;
| };

The corresponding spot in qapi-visit.c calls visit_type_FOO(), which
first calls visit_start_struct() to allocate or deallocate the member
and handle a layer of {} from the JSON stream, then visits the
members. To peel off the indirection and the memory management that
comes with it, we inline this call, then suppress allocation /
deallocation by passing NULL to visit_start_struct(), and adjust the
member visit:

| switch ((*obj)->type) {
| case QTYPE_QDICT:
|- visit_type_BlockdevOptions(v, name, &(*obj)->u.definition, &err);
|+ visit_start_struct(v, name, NULL, 0, &err);
|+ if (err) {
|+ break;
|+ }
|+ visit_type_BlockdevOptions_fields(v, &(*obj)->u.definition, &err);
|+ error_propagate(errp, err);
|+ err = NULL;
|+ visit_end_struct(v, &err);
| break;
| case QTYPE_QSTRING:
| visit_type_str(v, name, &(*obj)->u.reference, &err);

The visit of non-object fields is unchanged.

Backports commit becceedc4d9bc1435099c90a0514945a89844d3a from qemu
2018-02-20 16:32:11 -05:00
..
crypto crypto: Clean up includes 2018-02-19 00:47:40 -05:00
default-configs arm64eb: add support for ARM64 big endian. 2017-04-24 23:30:01 +08:00
docs docs: clarify memory region lifecycle 2018-02-12 15:11:21 -05:00
fpu all: Clean up includes 2018-02-19 01:34:28 -05:00
hw x86: Clean up includes 2018-02-19 01:00:09 -05:00
include qom: Correct object_property_get_int() description 2018-02-20 11:52:16 -05:00
qapi qmp: Don't abuse stack to track qmp-output root 2018-02-20 08:09:56 -05:00
qobject qapi: Convert QType into QAPI built-in enum type 2018-02-19 21:47:05 -05:00
qom cpu: Add callback to check architectural watchpoint match 2018-02-20 11:43:56 -05:00
scripts qapi: Don't box struct branch of alternate 2018-02-20 16:32:11 -05:00
target-arm target-arm: Add PMUSERENR_EL0 register 2018-02-20 15:36:31 -05:00
target-i386 target-i386: Implement FSGSBASE 2018-02-20 14:45:58 -05:00
target-m68k m68k: Clean up includes 2018-02-19 01:06:05 -05:00
target-mips mips: Clean up includes 2018-02-19 00:45:08 -05:00
target-sparc sparc: Clean up includes 2018-02-19 00:52:41 -05:00
tcg target-i386: Implement BNDMK 2018-02-20 14:02:31 -05:00
util error: New error_fatal 2018-02-20 08:22:27 -05:00
aarch64.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
aarch64eb.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
accel.c all: Clean up includes 2018-02-19 01:34:28 -05:00
arm.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
armeb.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
CODING_STYLE import 2015-08-21 15:04:50 +08:00
configure tcg: Drop ia64 host support 2018-02-04 18:33:02 -05:00
COPYING import 2015-08-21 15:04:50 +08:00
COPYING.LIB import 2015-08-21 15:04:50 +08:00
cpu-exec-common.c exec: Clean up includes 2018-02-19 00:49:55 -05:00
cpu-exec.c exec: Clean up includes 2018-02-19 00:49:55 -05:00
cpus.c exec: Clean up includes 2018-02-19 00:49:55 -05:00
cputlb.c exec: Clean up includes 2018-02-19 00:49:55 -05:00
exec.c exec: Clean up includes 2018-02-19 00:49:55 -05:00
gen_all_header.sh arm64eb: add support for ARM64 big endian. 2017-04-24 23:30:01 +08:00
glib_compat.c crypto: introduce new module for computing hash digests 2018-02-17 15:23:17 -05:00
HACKING import 2015-08-21 15:04:50 +08:00
header_gen.py target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
ioport.c all: Clean up includes 2018-02-19 01:34:28 -05:00
LICENSE import 2015-08-21 15:04:50 +08:00
m68k.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
Makefile qapi: Turn generators' mandatory option -i into an argument 2018-02-19 15:22:27 -05:00
Makefile.objs crypto: move crypto objects out of libqemuutil.la 2018-02-17 15:23:50 -05:00
Makefile.target tcg: split tcg_op_defs to -common 2018-02-17 15:23:51 -05:00
memory.c qom: Swap 'name' next to visitor in ObjectPropertyAccessor 2018-02-19 23:14:37 -05:00
memory_mapping.c all: Clean up includes 2018-02-19 01:34:28 -05:00
mips.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
mips64.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
mips64el.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
mipsel.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
powerpc.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
qapi-schema.json qapi: Lazy creation of array types 2018-02-19 18:55:35 -05:00
qemu-log.c all: Clean up includes 2018-02-19 01:34:28 -05:00
qemu-timer.c all: Clean up includes 2018-02-19 01:34:28 -05:00
rules.mak import 2015-08-21 15:04:50 +08:00
softmmu_template.h exec.c: Pass MemTxAttrs to iotlb_to_region so it uses the right AS 2018-02-17 23:19:00 -05:00
sparc.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
sparc64.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00
tcg-runtime.c all: Clean up includes 2018-02-19 01:34:28 -05:00
translate-all.c all: Clean up includes 2018-02-19 01:34:28 -05:00
translate-all.h translate-all: remove unnecessary argument to tb_invalidate_phys_range 2018-02-13 09:04:51 -05:00
translate-common.c exec: Clean up includes 2018-02-19 00:49:55 -05:00
unicorn_common.h qom/cpu: Add MemoryRegion property 2018-02-18 21:54:50 -05:00
VERSION import 2015-08-21 15:04:50 +08:00
vl.c vl.c: Remove periods and exclamation points from error messages 2018-02-17 15:24:14 -05:00
vl.h import 2015-08-21 15:04:50 +08:00
x86_64.h target-arm: Implement checking of fired watchpoint 2018-02-20 11:50:29 -05:00