So is your problem now solved? To rephrase my response: If you are injecting code into a module, can't you also simply inject a new import?
On Sat, May 4, 2019 at 10:33 PM Duan Bing <[email protected]> wrote: > Hi, Sam: > Yes, I have an implementation based on WAVM, design doc : > https://github.com/duanbing/WAVM/blob/master/Gas.md . > > 'Sam Clegg' via emscripten-discuss <[email protected]> > 于2019年5月4日周六 下午3:14写道： > >> One way to achieve this might be to use binaryen tools to inject your >> wasm code into the module. One of the simplest ways would be use wasm-dis >> to turn the module into text, when wasm-as to re-assembly it after adding >> your new imports and code. >> >> *From: *Duan Bing <[email protected]> >> *Date: *Fri, May 3, 2019 at 8:14 AM >> *To: * <[email protected]> >> >> Thanks, Floh. >>> I didn't compile it into a library, so visibility attribute seems not >>> take effect. >>> As we can see from emscripth.h >>> #define EMSCRIPTEN_KEEPALIVE __attribute__((used)) __attribute__ >>> ((visibility ("default"))) actually, this macro affects the function >>> with definition, but not for declaration only from my trials. >>> >>> >>> Floh <[email protected]> 于2019年5月3日周五 上午1:12写道： >>> >>>> PS: I've been looking around a bit, and maybe this is the better >>>> solution (via __attribute__(...)): >>>> >>>> __attribute__((visibility("default"))) void foo(void); >>>> >>>> This should be the clang equivalent to __declspec(dllimport) in the >>>> Visual Studio compiler, see here: >>>> >>>> https://webassembly.org/docs/dynamic-linking/ >>>> >>>> On Thursday, 2 May 2019 17:06:27 UTC+2, Duan Bing wrote: >>>>> >>>>> Thanks, your new idea works for me. the motivation of doing this is >>>>> that I will call this imported function while I will insert some wasm code >>>>> to the original wasm file later, similar to this project had done >>>>> https://github.com/ewasm/wasm-metering , but by a different PL. so I >>>>> don't want the original wasm developer to use this function(I will insert >>>>> foo dynamically with a mangling name ), and I also occupy the import index >>>>> space by doing this in advance. >>>>> >>>>> Floh <[email protected]> 于2019年5月2日周四 下午10:56写道： >>>>> >>>>>> Ah ok, I misunderstood your question, apologies. I don't know how one >>>>>> would add a function declaration to the WASM imports table like this. >>>>>> EMSCRIPTEN_KEEPALIVE and the "-s EXPORTED_FUNCTIONS" linker option would >>>>>> work for the "other side" (some WASM module exporting functions to the >>>>>> outside). >>>>>> >>>>>> Complete guess, but maybe you need some "dummy code" that's >>>>>> guaranteed to stay in the importing WASM module, even though this is >>>>>> never >>>>>> called? So that the linker would recognize the function as an "import". >>>>>> >>>>>> Something like this: >>>>>> >>>>>> extern "C" void foo(); >>>>>> // dummy_imports() is never called, but will not be removed because >>>>>> of EMSCRIPTEN_KEEPALIVE >>>>>> EMSCRIPTEN_KEEPALIVE void dummy_imports(void) { >>>>>> foo(); >>>>>> } >>>>>> >>>>>> But as I said, this is complete guess. >>>>>> >>>>>> On Thursday, 2 May 2019 16:22:28 UTC+2, Duan Bing wrote: >>>>>>> >>>>>>> Thanks, Floh. it works when the function is defined. >>>>>>> Actually, my function is an external function declaration, like >>>>>>> extern "C" void foo(); >>>>>>> >>>>>>> It doesn't work even I declare like this: >>>>>>> extern "C" void EMSCRIPTEN_KEEPALIVE foo(). >>>>>>> >>>>>>> Do you have any idea for this situation? >>>>>>> >>>>>>> Floh <[email protected]> 于2019年5月2日周四 下午10:13写道： >>>>>>> >>>>>>>> Have a look at EMSCRIPTEN_KEEPALIVE: >>>>>>>> https://emscripten.org/docs/api_reference/emscripten.h.html#c.EMSCRIPTEN_KEEPALIVE, >>>>>>>> this prevents a C/C++ function from being removed even when it isn't >>>>>>>> referenced by other C/C++ code (normally this is used to call C >>>>>>>> functions >>>>>>>> from the JS side). >>>>>>>> >>>>>>>> On Thursday, 2 May 2019 08:16:43 UTC+2, Duan Bing wrote: >>>>>>>>> >>>>>>>>> I declare an external function in C source file, but never used by >>>>>>>>> the code, then compile it to wasm by EMCC. there is no doubt the >>>>>>>>> external >>>>>>>>> function will be eliminated by the compiler. >>>>>>>>> >>>>>>>>> Is there any approach to keep this external function and then be >>>>>>>>> compiled to an import function in wasm? >>>>>>>>> >>>>>>>>> The motivation to remain the external function is that I want to >>>>>>>>> insert some wasm code in the wasm file after it's generated. >>>>>>>>> >>>>>>>>> Thanks all! >>>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "emscripten-discuss" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to [email protected]. >>>>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>>>> >>>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "emscripten-discuss" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to [email protected]. >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "emscripten-discuss" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "emscripten-discuss" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "emscripten-discuss" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to the Google Groups > "emscripten-discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. 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