Igor you should add that to a class comment and into the wiki of NB.
On Jul 12, 2013, at 5:43 PM, Igor Stasenko <siguc...@gmail.com> wrote: > Hi, there , > i've been working last two weeks on reviewing the code in NB, > and update configuration & making tests green etc.. > So, here the summary: > > 0. New stuff: > > external structures (NBExternalStructure) now is normal objects (not > var-byte ones), and using 'data' ivar indirection like in > NBExternalArray, so you can allocate external struct on both external > heap and object memory, e.g.: > > struct := MyStructClass externalNew. > or: > struct := MyStructClass new. > (so, it is similar to NBExternalArray). > > - a function with signature > > MyStruct * foo () > > which returns a pointer to struct, now will return an instance of > MyStruct with the address, so you can use it directly , e.g.: > > struct := self callFoo. > > value := struct field1. > struct field2: 10 > > etc.. > > Thanks to Ciprian for introducing the change. I just polished a bit > and fixed some mistakes. > > 1. NBExternalTypeValue>>address > should not exist. > You simply cannot use freely an address to object's internal field > because object can move in memory. > > (the tests in > NBFFIExternalValueTests > testOutIntArg > testOutValueArg > testOutVoidArg > > is changed accordingly) > > 2. In NBExternalEnumerationType: pushing a pointer to this type is not > allowed, since it makes no sense. > > But the mistake there was to generate a code which fails primitive > with an error message, > instead of failing much much sooner - at code generation stage, since > it is already known that user specified wrong type. > > 3. I reverting generic pushAsPointer: to accept varbyte objects > instead of just ByteArray object. > - removing #specialPush:asPointer:endLabel: > because it will be not used (btw, > in NBExternalStructureType>>specialPush:asPointer:endLabel: , there > was same mistake that > it generates code to checking a pointer arity at runtime, while it is > already known during code generation time: > > asm decorateWith: 'arity checking' during: [ |pointerArityOk| > pointerArityOk := asm uniqueLabelName: 'pointerArityOk'. > asm mov: pointerArity asImm32 to: asm EAX; > cmp: asm EAX with: 1 asImm32; > je: pointerArityOk. > gen failWithMessage: 'Arity ', pointerArity printString,' not > allowed for ', objectClass name, 'objects'. > asm label: pointerArityOk]. > > since pointerArity is known, the produced code will be something like: > > mov: 1 to: EAX; > cmp: EAX with: 1; > je: pointerArityOk > > and makes no sense, because again it can just throw the error at code > generation time. > > 4. Added code to capture argument names (CompiledMethod>>nbArgumentNames) > and 'NativeBoost prepareForProduction', to ensure NB can work without > source code accessible. > > > 5. But the general expression, like in (1): > > object address > > gave me an interesting idea: what if we introduce a special type, say > NBObjectFieldAddress. > Consider the following problem: > imagine that you have a big array in object memory (byte array), > and you want to pass a pointer to n-th element of that array to some function. > Right now, there is no way how you can do it, and you can pass only a > pointer to array itself (which means it will always point to its first > element). > > So, the idea is to introduce a special type, and special object which > represents the address-of-object's-field, so you can tell: > > array := ByteArray new: 1000. > > address := array nbAddressAt: 500. "create an address object which > points to 500th element of given array" > > (and expression 'array nbAddress' is synonym to 'array nbAddressAt: 1'). > > self callSomeFunctionWith: address. > > The signature of C function which takes a pointer like: > > void foo (void * ptr) > > then should be changed to: > > void foo (NBObjectFieldAddress ptr) > > the only question, which remains , shall it use strict type checking > (so you have to change the signature), or allow to use such objects > with any signatures which takes a pointer to something, e.g. > extend generic NBExternalType>>pushAsPointer: to additionally check if > incoming argument is instance of NBObjectFieldAddress class. > > P.S. to try new config , load it: > > Gofer new > smalltalkhubUser: 'Pharo' project: 'NativeBoost'; > configuration; > load. > > > ConfigurationOfNativeBoost loadDevelopment. "which should load 2.2 > version of it" > > > -- > Best regards, > Igor Stasenko. >
