o blocks are implemented as a variation of procedure variables
o declaration of a block variable: "test: procedure(c: char) is block;"
(C equivalent: (void)(^test)(char c) )
o the compiler automatically converts procedures/functions whose address
is passed to a block parameter or assigned to a block variable into
a "block". This consists of
1) generating a block descriptor (containing the size of the "block
literal" (see below) and the signature of the invocation function
encoded as an Objective-C selector)
2) generating a wrapper function around the original funcion (with C
calling convention), that has an extra first hidden parameter
(marked as vo_is_parentfp in the compiler) whose type is a pointer
to the describing "block literal"
3) generating the "block literal", which contains a pointer to an
external variable indicating whether this block captures context or
not, some flags (see compiler/blockutl.get_block_literal_flags for
info), a pointer to the wrapper function and a pointer to the
descriptor. In the future, it will also contain captured variables.
o right now, only global procedures/functions can be converted to blocks
(because they don't require state capturing). The next steps are (Object
Pascal) methods (not Objective-C methods, because Objective-C method
procvars don't exist) and finally nested functions
o on Mac OS X, the functionality will only work on Mac OS X 10.7 and later,
because we have to use the so-called "ABI.2010.3.16" to ensure that
our blocks aren't called as variadic functions by the runtime (which
came out after the Mac OS X 10.6 release)
o while the currently implemented functionality does not require any
library support at all, there's no use enabling it on other platforms
because unless it has been confirmed to work with a blocks runtime,
there's no point in using blocks (they're just somewhat bulky procvars
right now). Enabling it on other platforms (in combination with the
GNUStep Objective-C run time), should simply be a matter of adding
the right {$linklib xxx} statement to rtl/inc/blockrtl.pp file, adding
that file to Makefile.fpc for that platform and adding that platform
to the compiler/systems.systems_blocks_supported set
git-svn-id: branches/blocks@28232 -
This change became necessary of the following reasons:
- Records don't support inheritance, thus for "record helpers" some creativity would have been necessary to implement them; with the new implementation this is more easily
- the new approach allows for easy checks regarding virtual methods and their overrides which would have been more complicated in the old variant
- if someone feels the need the types of helpers (object, interface) can be added rather easily
- unnecessary things like VMT generation can be disabled now
details:
- msg*:
* moved some messages from parser to type
* adjusted a message ("class helper" => "helper")
- symdef.pas:
* renamed "helperparent" to "extendeddef" and changed its type from "tobjectdef" to "tabstractrecorddef", so records can be extended as well (somewhen in the near future)
* removed "finish_class_helper" method as it isn't necessary (luckily I haven't yet adjusted the ObjC variant)
* changed name of "is_objectpascal_classhelper" to "is_objectpascal_helper" to reflect that this function applies to all helper types
* tobjectdef.create: ImplementedInterfaces isn't created for odt_helper anymore
* tobjectdef.alignment: for helpers it's the same as for classes although this shouldn't be used anywhere...
* tobjectdef.vmtmethodoffset: set to 0 for helpers to be sure...
* tobjectdef.needs_inittable: not needed for helpers (no fields allowed)
* is_objectpascal_helper: only needs check for "odt_helper" object type
- symconst.pas:
* changed odt_classhelper to more general odt_helper
* added new type "thelpertype" which is used to check that "(record|class) helper" corresponds with the given extended type (as Delphi XE checks this as well this strict solution can be kept for modes Delphi and ObjFPC)
- symtable.pas:
* extended "searchsym_in_class" with the possibility to disable the search for helper methods (needed for inherited) => this implies changing all occurences of "searchsym_in_class" with a "true" except some special locations
* renamed "search_objectpascal_classhelper" to "search_objectpascal_helper"
* searchsym_in_class:
** when an extended method is defined with "overload" it can be that a same named method of the extended class might be called (sadly this means that this search was unnecessary...)
** contextclassh is the def of the helper in the case of an inherited call inside the helper's implementation
** when methods inside a helper are searched, it must be searched in the extended type first
- ptype.pas:
* single_type is used to parse the parent of a helper as well, so allow a helper if the stoParseClassParent is given (needs check in pdecobj.pas/parse_class_parents for normal classes)
* read_named_type: currently the only case when something <> ht_none is passed to the modified parse_objdec (see below) is when the combination "class helper" is encountered ("record helper" will be another one)
- pinline.pas: adjustment for extended "searchsym_in_class"
- pexpr.pas:
* adjustments regarding "searchsym_in_class" and "is_objectpascal_helper"
* factor/factor_read_id: moved the check for "TSomeClassType.SomeMethod" outside of the "is_class" check
* factor:
** in case of an inherited we need to search inside the extended type first (Note: this needs to be extended to find methods in the helper parent if no method is found in the extended type)
** we also need to disable the search for helper methods when searching for an inherited method (Note: it might be better to introduce a enum to decide whether a helper method should search before or after the methods of the extended type or even never)
- pdecsub.pas:
* insert_self_and_vmt_para: in a helper the type of Self is of the extended type
* pd_abstract, pd_final: more nice error message
* pd_override, pd_message, pd_reintroduce: adjusted checks because now "is_class" is no longer true for helpers
* proc_direcdata: allowed "abstract" for helpers (only to produce a more nice error message)
* parse_proc_direc: adjustment because of "is_objectpascal_helper"
- pdecobj.pas:
* adjustments regarding "is_objectpascal_helper"
* adjusted object_dec to take the type of the helper (class, record) as a parameter to be able to check whether the correct extended type was given
* struct_property_dec: properties are allowed in helpers
* parse_object_options: nothing to be parsed for helpers (at least I hope so ^^)
* parse_parent_classes:
** the parent of a helper is now parsed as a normal parent, the extended type is parsed in an extra procedure
** check for "sealed" no longer needed
** added check that the parsed parent of a helper is indeed a helper
** allow to parse the closing ")" of the helper's parent
* parse_extended_class:
** new procedure that parses the type which is extended
** it checks that the extended type is a class for "class helper" and a record for "record helper"
** it checks that a helper extends the same class or a subclass for class helpers
** it checks that a helper extends the same record for record helpers
* parse_object_members:
** "type", "const", "var" is allowed in helpers
** don't exclude flags regarding virtual methods, they are needed for the checks in mode Delphi (this implies that VMT loading must be disabled for helpers)
* object_dec:
** don't change "odt_helper" to "odt_class", but still include the "oo_is_classhelper" flag
** allow the parsing of object options (there are none)
** parse the extended type for helpers
- pdecl.pas
* adjustment because of extension of object_dec
* types_dec: remove the call to finish_classhelper
- objcdef.pas
* objcaddencodedtype, objcdochecktype: add references to helpers as implicit pointers although that should not be used in any way...
- nld.pas
* tloadnode.pass_typecheck: self is a reference to the extended type
- nflw.pas
* create_for_in_loop: adjustment because of changed procedure and inheritance type
- ncgrtti.pas
* TRTTIWriter.write_rtti_data: disable for helpers for now (I need to check what Delphi does here)
- ncgld.pas
* tcgloadnode.pass_generate_code: virtual methods of helpers are treated as normal methods
- ncgcal.pas
* tcgcallnode.pass_generate_code: virtual methods of helpers are treated as normal methods
- ncal.pas
* tcallnode.pass_typecheck: adjust for extension of tcallcandidates constructor
- htypechk.pas
* tcallcandidates declaration: extend some methods to (dis)allow the search for helper methods (needed for inherited)
* tcallcandidates.collect_overloads_in_struct:
** search first in helpers for methods and stop if none carries the "overload" flag
** move the addition of the procsyms to an extra nested procedure because it's used for helper methods and normal struct methods
git-svn-id: branches/svenbarth/classhelpers@16947 -
Objective-C methods or which are fields of Objective-C classes (since they
are basically opaque to the Objective-C runtime) + fixed tobjc11 so it
expects classes to be encoded as opaque types
* give a proper error message when using illegal field/parameter types in
Objective-C classes/methods instead of an internal error (only checked
during rtti generation rather than during parsing, because during parsing
some types may still be forwarddefs)
* split objcutil in objcdef and objcutil, with objcdef depending only on
the symtable so it can be used in symdef
git-svn-id: trunk@14838 -
