"no output file specified" can be ignored, but I am confused why it appears... I can't reproduce it with a similar link command locally.
On Mon, Dec 1, 2025 at 6:41 AM John Dallman <[email protected]> wrote: > On Sat, Nov 29, 2025 at 7:59 PM 'Sam Clegg' via emscripten-discuss < > [email protected]> wrote: > > > The reason for the warning is the `-sSAFE_HEAP=1` flag. This flag > requires us to > > run a binaryen pass over the final output, and currently whenever we run > any binaryen > > passes, and we also have `-g`, then we issue this warning. > > > > Perhaps the warning should be rephrased or downgraded in the case when > optimization > > is not actually requested. Alon would probably know which is the best > option here. > > That would be welcome. What does the "warning: no output file specified, > not emitting output" message that comes just after it signify? > > Thanks, > > John > > > > On Sat, Nov 29, 2025 at 7:59 PM 'Sam Clegg' via emscripten-discuss < > [email protected]> wrote: > >> I think the warning you are seeing might be a little misleading in this >> case. >> >> The reason for the warning is the `-sSAFE_HEAP=1` flag. This flag >> requires us to run a binaryen pass over the final output, and currently >> whenever we run any binaryen passes, and we also have `-g`, then we issue >> this warning. >> >> Perhaps the warning should be rephrased or downgraded in the case when >> optimization is not actually requested. Alon would probably know which >> is the best option here. >> >> Cheers, >> sam >> >> On Thu, Nov 27, 2025 at 6:04 AM John Dallman <[email protected]> >> wrote: >> >>> > You can look at the JS output file to see the extra assertions are >>> emitted for >>> > -sASSERTIONS=2. Perhaps diff against a build without that flag. You >>> will see >>> > the flag adds stack checks and other things. >>> >>> I will need guidance as to what to look for. My knowledge of JavaScript >>> is minimal: I'm a C programmer who finds JS quite confusing. >>> >>> > Check your full link command - you likely have an -O1 or -O2 or such, >>> in addition to the -O0. >>> >>> Nope. >>> >>> > If that's not it, what is your full link command? >>> >>> em++ --pre-js /Path/to/kid_node_prerun.js -sMAXIMUM_MEMORY=4000MB >>> -sEXPORTED_FUNCTIONS=ENV,_main \ >>> -sALLOW_MEMORY_GROWTH -sSTACK_SIZE=4096KB -sNODERAWFS -g >>> --emit-symbol-map -sASSERTIONS=2 \ >>> -sSAFE_HEAP=1 /Path/to/lsp/kernel.o clu/object_plus.o lsp/lisp.o >>> /Path/to/lib/webasm/aga_fix.o /Path/to/system/release/kid_support.a >>> /Path/to/system/release/pskernel_archive.a -o /u/jgd/regimes/webasm/kid.js >>> >>> I get these warnings: >>> em++: warning: running limited binaryen optimizations because DWARF info >>> requested (or indirectly required) [-Wlimited-postlink-optimizations] >>> warning: no output file specified, not emitting output >>> >>> Thanks, >>> >>> John >>> >>> On Wed, Nov 26, 2025 at 6:52 PM Alon Zakai <[email protected]> wrote: >>> >>>> >>>> >>>> On Wed, Nov 26, 2025 at 6:37 AM John Dallman <[email protected]> >>>> wrote: >>>> >>>>> I'm linking with -sASSERTIONS=2 -O0, but not getting any assertions >>>>> going off. >>>>> >>>>> https://emscripten.org/docs/porting/Debugging.html says, in the DWARF >>>>> section: >>>>> >>>>> Optimization levels above -O1 or -Og increasingly degrade LLVM debug >>>>> information (as with other architectures), and optimization flags at link >>>>> time also disable Emscripten’s runtime ASSERTIONS checks. >>>>> >>>>> >>>>> Does -O0 disable ASSERTIONS checks? >>>>> >>>>> >>>> No, it doesn't. >>>> >>>> You can look at the JS output file to see the extra assertions are >>>> emitted for -sASSERTIONS=2. Perhaps diff against a build without that flag. >>>> You will see the flag adds stack checks and other things. >>>> >>>> >>>>> I get this warning when linking with, or without -O0: >>>>> >>>>> em++: warning: running limited binaryen optimizations because DWARF >>>>> info requested (or indirectly required) [-Wlimited-postlink-optimizations] >>>>> >>>>> >>>>> Which makes me wonder why binaryen optimisations are being done? >>>>> >>>>> >>>> Check your full link command - you likely have an -O1 or -O2 or such, >>>> in addition to the -O0. If that's not it, what is your full link command? >>>> >>>> >>>>> Thanks very much, >>>>> >>>>> John Dallman >>>>> >>>>> -- >>>>> 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]. >>>>> To view this discussion visit >>>>> https://groups.google.com/d/msgid/emscripten-discuss/CAH1xqgke4V%3DvuAOACzm2uf8WgKxQhnS9x4fC3-fLV_mKonZcHQ%40mail.gmail.com >>>>> <https://groups.google.com/d/msgid/emscripten-discuss/CAH1xqgke4V%3DvuAOACzm2uf8WgKxQhnS9x4fC3-fLV_mKonZcHQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >>>> 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]. >>>> To view this discussion visit >>>> https://groups.google.com/d/msgid/emscripten-discuss/CAEX4NpTc8RSEnCwtS%3De0Cin_sn7pZ18QTvhbO36NASMsmz1SVg%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/emscripten-discuss/CAEX4NpTc8RSEnCwtS%3De0Cin_sn7pZ18QTvhbO36NASMsmz1SVg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >>> 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]. >>> To view this discussion visit >>> https://groups.google.com/d/msgid/emscripten-discuss/CAH1xqgm9t_ZU-1p__bZJdGw543RO7UZRWBXW92_KdK%2BY09xGwg%40mail.gmail.com >>> <https://groups.google.com/d/msgid/emscripten-discuss/CAH1xqgm9t_ZU-1p__bZJdGw543RO7UZRWBXW92_KdK%2BY09xGwg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- >> 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]. >> To view this discussion visit >> https://groups.google.com/d/msgid/emscripten-discuss/CAL_va28s2ddFHAXm%3D-zHCDMzn224WyhCXirF8ru77Vi9dT%3DmJA%40mail.gmail.com >> <https://groups.google.com/d/msgid/emscripten-discuss/CAL_va28s2ddFHAXm%3D-zHCDMzn224WyhCXirF8ru77Vi9dT%3DmJA%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- > 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]. > To view this discussion visit > https://groups.google.com/d/msgid/emscripten-discuss/CAH1xqgnK6_oq246cyPRMVBtab5sxy5-4sQ9KHzUZ-DiVdeyVUQ%40mail.gmail.com > <https://groups.google.com/d/msgid/emscripten-discuss/CAH1xqgnK6_oq246cyPRMVBtab5sxy5-4sQ9KHzUZ-DiVdeyVUQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. 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