Error in webassembly compilation

sassanh

When I build my project in webassembly with Qt 5.13.0 and emscripten sdk 1.38.27-64bit I get a very very very long output that ends with this:

 (func $legalfunc$_llvm_bswap_i64 (; 47925 ;) (; has Stack IR ;) (param $0 i64) (result i64)
  (i64.or
   (i64.extend_i32_u
    (call $legalimport$_llvm_bswap_i64
     (i32.wrap_i64
      (local.get $0)
     )
     (i32.wrap_i64
      (i64.shr_u
       (local.get $0)
       (i64.const 32)
      )
     )
    )
   )
   (i64.shl
    (i64.extend_i32_u
     (call $getTempRet0)
    )
    (i64.const 32)
   )
  )
 )
)
Fatal: error in validating output
shared:ERROR: '.../emsdk/clang/e1.38.27_64bit/binaryen/bin/asm2wasm ./Application.temp.asm.js --total-memory=16777216 --trap-mode=clamp -O3 --mem-init=./Application.js.mem --mem-base=1024 --wasm-only -o ./Application.wasm --mvp-features' failed (1)

The last line being an error, any idea what's going wrong?

sassanh

Trying to increase total memory as suggested here: https://github.com/WebAssembly/binaryen/issues/1968
(It's done in .pro file by setting QMAKE_WASM_TOTAL_MEMORY variable)

sassanh

QMAKE_WASM_TOTAL_MEMORY didn't change the value of total-memory option of asm2wasm trying it manually

sassanh

Now getting LinkError: WebAssembly.instantiate(): memory import 732 is smaller than initial 16384, got 256 when I try to open my application in browser, it seems to be related to increasing TOTAL_MEMORY (https://github.com/emscripten-core/emscripten/issues/5069) I don't understand if I can't increase TOTAL_MEMORY why it's suggested in the other github thread I linked earlier.

sassanh

It's working now, I had to manually add -s TOTAL_MEMORY=64MB to LFLAGS in Makefile. I hope I'll find a better way cause otherwise I have to do it after each qmake.

I was able to run a big mobile application I wrote last year in webassembly, it's fantastic how it worked out of the box.

lorn.potter

You can either update your Qt, or apply this patch to your Qt:
https://codereview.qt-project.org/c/qt/qtbase/+/265523

Then you can set the total memory in yoru .pro file using
QMAKE_WASM_TOTAL_MEMORY

sassanh

5.13.1 is not released as an stable Qt version and I'm using 5.13.0 (latest stable version) so I applied the patch. Thanks!