Hi Manuel,
cool beans!
On Mon, Jun 27, 2022 at 3:54 AM Manuel Leuenberger maenuleu@gmail.com wrote:
Hi,
Ever since WebAssembly became a thing, I was wondering if this could become a target for VMs. People are already compiling FFMPEG and other complex tools. So I thought I would try as well.
So here I am to report to whom it may concern: OSVM compiles to WebAssembly, starts up (nearly), then looping infinitely Meaning: The VM mmaps the image file, loads plugins (SecurityPlugin made EXTERNAL), starts interpreter loop, but then loops the same bytecode sequence forever
Code lives at https://github.com/maenu/opensmalltalk-vm/tree/Cog/building/minheadless.cmak... if you want to try it out.
Below is the current Readme, including a short list of issues. Maybe some of you could give me a hint?
Cheers, Manuel
pharo.stack.spur.wasm
Compiles OSVM Stack interpreter to WebAssembly using the Emscripten compiler. Emscripten can be used as a drop-in replacement for gcc/clang and cmake. Based on MinHeadless Linux 32bit sources, as Emscripten provides Linux-like environment (pthreads, nanosleep, dlopen, file system). Check the latest few commits of maenu to see changed files.
https://github.com/maenu/opensmalltalk-vm/tree/Cog/building/minheadless.cmake/x86/pharo.stack.spur.wasm#current-issuesCurrent issues
Most adjustments are just putting EMSCRIPTEN in a macro or script. Should be fine, but should be tested to not interfere with other builds.
Compiles and runs, but seems to be stuck in initial GC and Heartbeat. Those could be related to incorrect get/set64() implementation.
Removed mmap address hint, as it caused errors.
Using argv eval '1 + 3' to do a simple eval does not terminate.
Interpreter repeats these bytecodes forever (what is this?):
Taking these from e.g. src/spur64.stack/interp.c they are
CASE(112) CASE(332) /*76*/ /* pushReceiverBytecode */
332
CASE(208)
CASE(209) CASE(210) CASE(211) CASE(212) CASE(213) CASE(214) CASE(215) CASE(216) CASE(217) CASE(218) CASE(219) CASE(220) CASE(221) CASE(222) CASE(223) CASE(384) /*128*/ i.e. send literal selector 0 with 0 args CASE(385) /*129*/ CASE(386) /*130*/ CASE(387) /*131*/ CASE(388) /*132*/ CASE(389) /*133*/ CASE(390) /*134*/ CASE(391) /*135*/ CASE(392) /*136*/ CASE(393) /*137*/ CASE(394) /*138*/ CASE(395) /*139*/ CASE(396) /*140*/ CASE(397) /*141*/ CASE(398) /*142*/ CASE(399) /*143*/ /* sendLiteralSelector0ArgsBytecode */
384
hence send literal selector 1 with 0 args
385
CASE(124) CASE(348) /*92*/ /* returnTopFromMethod */
348
CASE(501) /*245*/ /* longStoreTemporaryVariableBytecode */
501
CASE(136)
CASE(339) /*83*/ /* duplicateTopBytecode */
339
CASE(16)
CASE(320) /*64*/ /* pushTemporaryVariableBytecode */
320
CASE(224) CASE(225) CASE(226) CASE(227) CASE(228) CASE(229) CASE(230) CASE(231) CASE(232) CASE(233) CASE(234) CASE(235) CASE(236) CASE(237) CASE(238) CASE(239) CASE(400) /*144*/ CASE(401) /*145*/ i.e. send literal selector 1 with 1 arg CASE(402) /*146*/ CASE(403) /*147*/ CASE(404) /*148*/ CASE(405) /*149*/ CASE(406) /*150*/ CASE(407) /*151*/ CASE(408) /*152*/ CASE(409) /*153*/ CASE(410) /*154*/ CASE(411) /*155*/ CASE(412) /*156*/ CASE(413) /*157*/ CASE(414) /*158*/ CASE(415) /*159*/ /* sendLiteralSelector1ArgBytecode */
401
CASE(64)
CASE(272) /*16*/ /* pushLiteralVariableBytecode */
272
CASE(204)
CASE(380) /*124*/ /* bytecodePrimNew */ i.e. a send of #new from the special selector bytecode
380
If I had to guess what's going wrong I'd guess that the return bytecode 348 isn't correctly implemented.
https://github.com/maenu/opensmalltalk-vm/tree/Cog/building/minheadless.cmake/x86/pharo.stack.spur.wasm#build--runBuild & Run https://github.com/maenu/opensmalltalk-vm/tree/Cog/building/minheadless.cmake/x86/pharo.stack.spur.wasm#1-install-emscripten1. Install Emscripten
I installed Emscripten SDK https://emscripten.org/docs/getting_started/downloads.html to get an all-in-one package.
https://github.com/maenu/opensmalltalk-vm/tree/Cog/building/minheadless.cmake/x86/pharo.stack.spur.wasm#2-grab-an-image2. Grab an image
Grab a 32bit Smalltalk image and but it in the image folder. I used Pharo 9.
cd building/minheadless.cmake/x86/pharo.stack.spur.wasm mkdir image cd image curl https://get.pharo.org/32/90 | bash
./mvm_configure_variant debug Debug && make -C debug install
https://github.com/maenu/opensmalltalk-vm/tree/Cog/building/minheadless.cmake/x86/pharo.stack.spur.wasm#4-run-a-web-server4. Run a web server
emrun --port 9090 --serve_root ../../../../ --no_browser .
http://localhost:9090/building/minheadless.cmake/x86/pharo.stack.spur.wasm/d...
https://github.com/maenu/opensmalltalk-vm/tree/Cog/building/minheadless.cmake/x86/pharo.stack.spur.wasm#6-inspect-running-vm6. Inspect running VM
The VM is compiled with DWARF debug information, which is understood by the Chrome debugger. So we can step through the C sources of the WebAssembly, pretty nifty.
- Inspect WebAssembly (at the bottom)
https://webassembly.org/getting-started/developers-guide/
- Emscripten doc (Porting)
https://emscripten.org/docs/porting/index.html
- Emscripten settings https://emsettings.surma.technology/