Function Pointers and dynamic linking (function signature mismatch)

[gl84]

I'm trying to use boost regex expressions with a custom build icu (and latest tot upstream emscripten). I always get an error

exception thrown: RuntimeError: function signature mismatch,RuntimeError: function signature mismatch
    at legalstub$dynCall_jiii (wasm-function[12507]:11)
    at Object.Module.dynCall_jiii (/Test.js:19640:40)
    at invoke_jiii (/Test.js:27738:34)
    at legalfunc$invoke_jiii (wasm-function[12528]:9)
    at boost::re_detail_106900::basic_regex_creator<int, boost::icu_regex_traits>::basic_regex_creator(boost::re_detail_106900::regex_data<int, boost::icu_regex_traits>*) (wasm-function[7314]:136)
....

In trying to reproduce above problem in a simpler setting I found that when using function pointers to functions in side modules that return int64_t values I get the same error message
RuntimeError: function signature mismatch. The failure seems to be similar (but still different) to #9850 which was fixed in PR #9855.

I created a small combined test case with 4 files (without the boost/icu clutter) that reproduce the problem with the function pointers:
side.hpp:

#ifdef __EMSCRIPTEN__
    #include <emscripten.h>
#else
    #define EMSCRIPTEN_KEEPALIVE
#endif
#include <cstdint>

EMSCRIPTEN_KEEPALIVE int32_t function_ret_32(int32_t i, int32_t j, int32_t k);
EMSCRIPTEN_KEEPALIVE int64_t function_ret_64(int32_t i, int32_t j, int32_t k);

side.cpp:

#include "side.hpp"
int32_t function_ret_32(int32_t i, int32_t j, int32_t k) {
    return 32;
}
int64_t function_ret_64(int32_t i, int32_t j, int32_t k) {
    return 64;
}

main.cpp:

#include <cstdio>
#include <cinttypes>
#include "side.hpp"

typedef int32_t (*fp_type_32)(int32_t, int32_t, int32_t);
typedef int64_t (*fp_type_64)(int32_t, int32_t, int32_t);

int32_t internal_function_ret_32(int32_t i, int32_t j, int32_t k) {
    return 32;
}
int64_t internal_function_ret_64(int32_t i, int32_t j, int32_t k) {
    return 64;
}

int main() {
    fp_type_32 fp32_internal = &internal_function_ret_32;
    fp_type_32 fp32_external = &function_ret_32;
    fp_type_64 fp64_external = &function_ret_64;
    fp_type_64 fp64_internal = &internal_function_ret_64;
    int32_t ires32 = fp32_internal(0,0,0);
    printf("res32 - internal %d\n",ires32);
    int32_t eres32 = fp32_external(0,0,0);
    printf("res32 - external %d\n",eres32);

    int64_t ires64 = fp64_internal(0,0,0);
    printf("res64 - internal %" PRId64 "\n",ires64);
    int64_t eres64 = fp64_external(0,0,0);
    printf("res64 - external %" PRId64 "\n",eres64);
    return 0;
}

preload.js:

if (typeof(Module) === "undefined") Module = {};
Module.dynamicLibraries = ['side.wasm'];

Compiling the side module with
em++ -g --profiling -Wall -fPIC -s WASM=1 side.cpp -s SIDE_MODULE=2 -o side.wasm

Compiling the main module with
em++ -o main.js -g --profiling -Wall main.cpp -s MAIN_MODULE=1 -s EXPORTED_FUNCTIONS=['_main'] --pre-js preload.js

Running the program leads to the RuntimeError when fp64_external is called. Without the fix #9855 the line that should produce output res64 - internal 64 fails.

btw: Thanks for the great work! It is a lot of fun working with emscripten.

[kripken]

Thanks @gl84 , great testcase!

Fix in #9906. Turns out we were missing a lookup for a non-legalized (original) version from side modules, so it only worked in the same module.

[gl84]

Thanks @kripken for the fast fixing!

The PR fixes also my original issue.