Error when building O3 or O2 optimization is enabled

[altanozlu]

/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:272 throw new JS_Parse_Error(message, line, col, pos); ^ TypeError: {} is not a function at new JS_Parse_Error (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:261:21) at js_error (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:272:15) at croak (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:742:17) at token_error (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:749:17) at unexpected (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:755:17) at Arguments.semicolon (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:775:51) at prog1 (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:1314:29) at simple_statement (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:906:35) at /Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:816:35 at block_ (/Users/altanozlu/emsdk/emscripten/1.38.0/tools/eliminator/node_modules/uglify-js/lib/parse-js.js:999:32) Traceback (most recent call last): File "/Users/altanozlu/emsdk/emscripten/1.38.0/emcc", line 11, in <module> python_selector.run(__file__) File "/Users/altanozlu/emsdk/emscripten/1.38.0/tools/python_selector.py", line 38, in run sys.exit(run_by_import(filename, main) if on_allowed_version() else run_by_subprocess(filename)) File "/Users/altanozlu/emsdk/emscripten/1.38.0/tools/python_selector.py", line 13, in run_by_import return getattr(importlib.import_module(os.path.basename(filename)), main)() File "/Users/altanozlu/emsdk/emscripten/1.38.0/emcc.py", line 1902, in run wasm_text_target, misc_temp_files, optimizer) File "/Users/altanozlu/emsdk/emscripten/1.38.0/emcc.py", line 2442, in do_binaryen emit_symbol_map=emit_symbol_map) File "/Users/altanozlu/emsdk/emscripten/1.38.0/tools/shared.py", line 2236, in minify_wasm_js js_file = Building.js_optimizer_no_asmjs(js_file, ['noPrintMetadata'] + passes) File "/Users/altanozlu/emsdk/emscripten/1.38.0/tools/shared.py", line 2105, in js_optimizer_no_asmjs subprocess.check_call(NODE_JS + [js_optimizer.JS_OPTIMIZER, filename] + passes, stdout=open(next, 'w')) File "/usr/local/Cellar/python@2/2.7.15/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 190, in check_call raise CalledProcessError(retcode, cmd) subprocess.CalledProcessError: Command '['/Users/altanozlu/emsdk/node/8.9.1_64bit/bin/node', '/Users/altanozlu/emsdk/emscripten/1.38.0/tools/js-optimizer.js', '/tmp/tmpg07KHy/a.bc.o.js.mem.js', 'noPrintMetadata', 'JSDCE', 'minifyWhitespace']' returned non-zero exit status 1

I get this error when i try to enable O2 or O3
this works : emcc deneme.cpp -s WASM=1 -o a.js -std=c++11 -s --llvm-opts "['-O3']" -O1
this doesn't work : emcc deneme.cpp -s WASM=1 -o a.js -std=c++11 -s --llvm-opts "['-O3']" -O2

[kripken]

This error could result from --pre-js or EM_ASM code that Uglify can't handle, see #5700, #6000.

We should really add a FAQ entry on this, I'll do that.

[altanozlu]

Is the difference between o1 and o2 just uglify ?

[kripken]

There are a few more differences too, like passing the higher optimization level to the LLVM optimizer.

You may be able to disable just the js opts part with -O2 --js-opts 0, but without those opts your JS will be much much bigger. Refactoring the tricky ES6 code to not be seen by the optimizer is usually better.

[altanozlu]

thanks i'm closing the issue.