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2016-02-19qapi: Change visit_start_implicit_struct to visit_start_alternateEric Blake
After recent changes, the only remaining use of visit_start_implicit_struct() is for allocating the space needed when visiting an alternate. Since the term 'implicit struct' is hard to explain, rename the function to its current usage. While at it, we can merge the functionality of visit_get_next_type() into the same function, making it more like visit_start_struct(). Generated code is now slightly smaller: | { | Error *err = NULL; | |- visit_start_implicit_struct(v, (void**) obj, sizeof(BlockdevRef), &err); |+ visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj), |+ true, &err); | if (err) { | goto out; | } |- visit_get_next_type(v, name, &(*obj)->type, true, &err); |- if (err) { |- goto out_obj; |- } | switch ((*obj)->type) { | case QTYPE_QDICT: | visit_start_struct(v, name, NULL, 0, &err); ... | } |-out_obj: |- visit_end_implicit_struct(v); |+ visit_end_alternate(v); | out: | error_propagate(errp, err); | } Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1455778109-6278-16-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-19qapi: Don't box branches of flat unionsEric Blake
There's no reason to do two malloc's for a flat union; let's just inline the branch struct directly into the C union branch of the flat union. Surprisingly, fewer clients were actually using explicit references to the branch types in comparison to the number of flat unions thus modified. This lets us reduce the hack in qapi-types:gen_variants() added in the previous patch; we no longer need to distinguish between alternates and flat unions. The change to unboxed structs means that u.data (added in commit cee2dedb) is now coincident with random fields of each branch of the flat union, whereas beforehand it was only coincident with pointers (since all branches of a flat union have to be objects). Note that this was already the case for simple unions - but there we got lucky. Remember, visit_start_union() blindly returns true for all visitors except for the dealloc visitor, where it returns the value !!obj->u.data, and that this result then controls whether to proceed with the visit to the variant. Pre-patch, this meant that flat unions were testing whether the boxed pointer was still NULL, and thereby skipping visit_end_implicit_struct() and avoiding a NULL dereference if the pointer had not been allocated. The same was true for simple unions where the current branch had pointer type, except there we bypassed visit_type_FOO(). But for simple unions where the current branch had scalar type, the contents of that scalar meant that the decision to call visit_type_FOO() was data-dependent - the reason we got lucky there is that visit_type_FOO() for all scalar types in the dealloc visitor is a no-op (only the pointer variants had anything to free), so it did not matter whether the dealloc visit was skipped. But with this patch, we would risk leaking memory if we could skip a call to visit_type_FOO_fields() based solely on a data-dependent decision. But notice: in the dealloc visitor, visit_type_FOO() already handles a NULL obj - it was only the visit_type_implicit_FOO() that was failing to check for NULL. And now that we have refactored things to have the branch be part of the parent struct, we no longer have a separate pointer that can be NULL in the first place. So we can just delete the call to visit_start_union() altogether, and blindly visit the branch type; there is no change in behavior except to the dealloc visitor, where we now unconditionally visit the branch, but where that visit is now always safe (for a flat union, we can no longer dereference NULL, and for a simple union, visit_type_FOO() was already safely handling NULL on pointer types). Unfortunately, simple unions are not as easy to switch to unboxed layout; because we are special-casing the hidden implicit type with a single 'data' member, we really DO need to keep calling another layer of visit_start_struct(), with a second malloc; although there are some cleanups planned for simple unions in later patches. visit_start_union() and gen_visit_implicit_struct() are now unused. Drop them. Note that after this patch, the only remaining use of visit_start_implicit_struct() is for alternate types; the next patch will do further cleanup based on that fact. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1455778109-6278-14-git-send-email-eblake@redhat.com> [Dead code deletion squashed in, commit message updated accordingly] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-19qapi: Adjust layout of FooList typesEric Blake
By sticking the next pointer first, we don't need a union with 64-bit padding for smaller types. On 32-bit platforms, this can reduce the size of uint8List from 16 bytes (or 12, depending on whether 64-bit ints can tolerate 4-byte alignment) down to 8. It has no effect on 64-bit platforms (where alignment still dictates a 16-byte struct); but fewer anonymous unions is still a win in my book. It requires visit_next_list() to gain a size parameter, to know what size element to allocate; comparable to the size parameter of visit_start_struct(). I debated about going one step further, to allow for fewer casts, by doing: typedef GenericList GenericList; struct GenericList { GenericList *next; }; struct FooList { GenericList base; Foo *value; }; so that you convert to 'GenericList *' by '&foolist->base', and back by 'container_of(generic, GenericList, base)' (as opposed to the existing '(GenericList *)foolist' and '(FooList *)generic'). But doing that would require hoisting the declaration of GenericList prior to inclusion of qapi-types.h, rather than its current spot in visitor.h; it also makes iteration a bit more verbose through 'foolist->base.next' instead of 'foolist->next'. Note that for lists of objects, the 'value' payload is still hidden behind a boxed pointer. Someday, it would be nice to do: struct FooList { FooList *next; Foo value; }; for one less level of malloc for each list element. This patch is a step in that direction (now that 'next' is no longer at a fixed non-zero offset within the struct, we can store more than just a pointer's-worth of data as the value payload), but the actual conversion would be a task for another series, as it will touch a lot of code. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1455778109-6278-10-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Drop unused error argument for list and implicit structEric Blake
No backend was setting an error when ending the visit of a list or implicit struct, or when moving to the next list node. Make the callers a bit easier to follow by making this a part of the contract, and removing the errp argument - callers can then unconditionally end an object as part of cleanup without having to think about whether a second error is dominated by a first, because there is no second error. A later patch will then tackle the larger task of splitting visit_end_struct(), which can indeed set an error. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-24-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Drop unused 'kind' for struct/enum visitEric Blake
visit_start_struct() and visit_type_enum() had a 'kind' argument that was usually set to either the stringized version of the corresponding qapi type name, or to NULL (although some clients didn't even get that right). But nothing ever used the argument. It's even hard to argue that it would be useful in a debugger, as a stack backtrace also tells which type is being visited. Therefore, drop the 'kind' argument as dead. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-22-git-send-email-eblake@redhat.com> [Harmless rebase mistake cleaned up] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Swap 'name' in visit_* callbacks to match public APIEric Blake
As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-21-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Make all visitors supply uint64 callbacksEric Blake
Our qapi visitor contract supports multiple integer visitors, but left the type_uint64 visitor as optional (falling back on type_int64); which in turn can lead to awkward behavior with numbers larger than INT64_MAX (the user has to be aware of twos complement, and deal with negatives). This patch does not address the disparity in handling large values as negatives. It merely moves the fallback from uint64 to int64 from the visitor core to the visitors, where the issue can actually be fixed, by implementing the missing type_uint64() callbacks on top of the respective type_int64() callbacks, and with a FIXME comment explaining why that's wrong. With that done, we now have a type_uint64() callback in every driver, so we can make it mandatory from the core. And although the type_int64() callback can cover the entire valid range of type_uint{8,16,32} on valid user input, using type_uint64() to avoid mixed signedness makes more sense. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-15-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Prefer type_int64 over type_int in visitorsEric Blake
The qapi builtin type 'int' is basically shorthand for the type 'int64'. In fact, since no visitor was providing the optional type_int64() callback, visit_type_int64() was just always falling back to type_int(), cementing the equivalence between the types. However, some visitors are providing a type_uint64() callback. For purposes of code consistency, it is nicer if all visitors use the paired type_int64/type_uint64 names rather than the mismatched type_int/type_uint64. So this patch just renames the signed int callbacks in place, dropping the type_int() callback as redundant, and a later patch will focus on the unsigned int callbacks. Add some FIXMEs to questionable reuse of errp in code touched by the rename, while at it (the reuse works as long as the callbacks don't modify value when setting an error, but it's not a good example to set) - a later patch will then fix those. No change in functionality here, although further cleanups are in the pipeline. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-14-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Dealloc visitor does not need a type_size()Eric Blake
The intent of having the visitor type_size() callback differ from type_uint64() is to allow special handling for sizes; the visitor core gracefully falls back to type_uint64() if there is no need for the distinction. Since the dealloc visitor does nothing for any of the int visits, drop the pointless size handler. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-5-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Drop dead dealloc visitor variableEric Blake
Commit 0b9d8542 added StackEntry.is_list_head, but forgot to delete the now-unused QapiDeallocVisitor.is_list_head. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-4-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-04qapi: Clean up includesPeter Maydell
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1454089805-5470-8-git-send-email-peter.maydell@linaro.org
2015-09-21qapi: Introduce a first class 'any' typeMarkus Armbruster
It's first class, because unlike '**', it actually works, i.e. doesn't require 'gen': false. '**' will go away next. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
2015-06-19qom: Make enum string tables const-correctDaniel P. Berrange
The enum string table parameters in various QOM/QAPI methods are declared 'const char *strings[]'. This results in const warnings if passed a variable that was declared as static const char * const strings[] = { .... }; Add the extra const annotation to the parameters, since neither the string elements, nor the array itself should ever be modified. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-09-26qapi: dealloc visitor, implement visit_start_unionMichael Roth
If the .data field of a QAPI Union is NULL, we don't need to free any of the union fields. Make use of the new visit_start_union interface to access this information and instruct the generated code to not visit these fields when this occurs. Cc: qemu-stable@nongnu.org Reported-by: Fam Zheng <famz@redhat.com> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-09Revert "qapi: Clean up superfluous null check in qapi_dealloc_type_str()"Peter Lieven
This reverts commit 25a7017555f1b4aeb543b5d323ff4afb8f9c5437. Turns out the argument *can* be null: QEMU now segfaults if it receives an invalid parameter via a qmp command instead of throwing an error. For example: { "execute": "blockdev-add", "arguments": { "options" : { "driver": "invalid-driver" } } } CC: qemu-stable@nongnu.org Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-03-03qapi: Clean up superfluous null check in qapi_dealloc_type_str()Markus Armbruster
Argument can't be null. No other Visitor method type_str() checks for null. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2013-11-05qapi: fix memleak by adding implict struct functions in dealloc visitorWenchao Xia
Otherwise member "base" is leaked in a qapi_free_STRUCTURE() call. Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1383676551-18806-2-git-send-email-xiawenc@linux.vnet.ibm.com Cc: qemu-stable@nongnu.org Signed-off-by: Anthony Liguori <aliguori@amazon.com>
2012-12-19misc: move include files to include/qemu/Paolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19qapi: move include files to include/qobject/Paolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19qapi: remove qapi/qapi-types-core.hPaolo Bonzini
The file is only including error.h and qerror.h. Prefer explicit inclusion of whatever files are needed. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-29qapi: fix qapi_dealloc_type_size parameter typeBruce Rogers
The second parameter to qapi_dealloc_type_size should be a uint64_t *, not a size_t *. This was causing our 32 bit x86 build to fail, since warnings are treated as errors. Signed-off-by: Bruce Rogers <brogers@suse.com> Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> Reviewed-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2012-11-26qapi: handle visitor->type_size() in QapiDeallocVisitorStefan Hajnoczi
visit_type_size() requires either visitor->type_size() or visitor_uint64() to be implemented, otherwise a NULL function pointer is invoked. It is possible to trigger this crash as follows: $ qemu-system-x86_64 -netdev tap,sndbuf=0,id=netdev0 \ -device virtio-blk-pci,netdev=netdev0 The 'sndbuf' option has type "size". Reviewed-by: Andreas Färber <afaerber@suse.de> Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-10-04qapi: dealloc visitor, support freeing of nested listsMichael Roth
Previously our logic for keeping track of when we're visiting the head of a list was done via a global bool. This can be overwritten if dealing with nested lists, so use stack entries to track this instead. Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-10-04qapi: dealloc visitor, fix premature free and iteration logicMichael Roth
Currently we do 3 things wrong: 1) The list iterator, in practice, is used in a manner where the pointer we pass in is the same as the pointer we assign the output to from visit_next_list(). This causes an infinite loop where we keep freeing the same structures. 2) We attempt to free list->value rather than list. visit_type_<type> handles this. We should only be concerned with the containing list. 3) We free prematurely: iterator function will continue accessing values we've already freed. This patch should fix all of these issues. QmpOutputVisitor also suffers from 1). Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-08-20Use glib memory allocation and free functionsAnthony Liguori
qemu_malloc/qemu_free no longer exist after this commit. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-07-21qapi: add QAPI dealloc visitorMichael Roth
Type of Visitor class that can be passed into a qapi-generated C type's visitor function to free() any heap-allocated data types. Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@gmail.com>