Yes, please file a ticket. I think the solution is going to be to set `force_object_files = True` on `libmalloc` in `tools/system_libs.spy`.. which means it (like compiler-rt et al) will be compiled as normal object files and not take part in LTO.
I am curious why this doesn't happen for dlmalloc too though.. cheers, sam On Tue, Sep 6, 2022 at 10:19 AM Floh <[email protected]> wrote: > Ok, I could cobble together a surprisingly simple reproducer here: > > https://github.com/floooh/emsc-calloc-emmalloc-repro > > -flto is indeed needed. So the 4 ingredients are: > > 1. malloc+memset being 'optimized' to a call to calloc via -O1 or better > 2. ...where malloc is called through a function pointer > 3. ...and emmalloc is used instead of the vanilla allocator > 4. ...and -flto must be enabled > > ...if any of this is missing, it works :D > > Should I write an Emscripten ticket too? > On Tuesday, 6 September 2022 at 18:43:52 UTC+2 Floh wrote: > >> Part of the mystery can be solved because clang replaces malloc+memset >> pairs with a single calloc call (only when optimization is enabled): >> >> https://www.godbolt.org/z/8r3Ydjs6a >> >> ...which explains why the problem shows up in release mode, but not debug >> mode. >> >> There still must be something else going on though, because I'm using the >> malloc+memset combo all the time together with emmalloc (and I guess the >> missing piece is that the malloc call is going through the function >> pointer). >> >> I'll tinker around a bit more with compiler options (but since this is a >> library, I cannot dictate what compiler options the code is built with). >> >> Cheers! >> >> On Monday, 5 September 2022 at 19:31:17 UTC+2 [email protected] wrote: >> >>> The other thing this could be related to is LTO. IIUC LTO itself can >>> generate calls to buildin functions (such as malloc and calloc) that are >>> not present in the original program. Does disabling LTO fix the problem? >>> >>> On Mon, Sep 5, 2022 at 10:28 AM Sam Clegg <[email protected]> wrote: >>> >>>> Can you trying building with `-Wl,--trace-symbol=calloc` rather than >>>> `LLD_REPORT_UNDEFINED=1` (I guess there are still some issues with that >>>> setting). >>>> >>>> Does the link time error tell you why calloc is being pulled in? (The >>>> JS compiler linker errors should do this but they often just say "top level >>>> C/C++"). >>>> >>>> On Sat, Sep 3, 2022 at 6:03 AM Floh <[email protected]> wrote: >>>> >>>>> I just stumbled over a very weird problem in a new sample for my sokol >>>>> headers which includes a non-trivial 3rd party C library - the spine-c >>>>> runtime ( >>>>> https://github.com/EsotericSoftware/spine-runtimes/tree/4.1/spine-c/spine-c >>>>> ) >>>>> >>>>> When building in release mode (but not in debug mode) the linker >>>>> complains about an unresolved 'calloc' call. Adding detailed output >>>>> via LLD_REPORT_UNDEFINED=1 I get tons of: >>>>> >>>>> wasm-ld: error: >>>>> /Users/floh/projects/fips-sdks/emsdk/upstream/emscripten/cache/sysroot/lib/wasm32-emscripten/lto/libemmalloc.a(emmalloc.o): >>>>> undefined symbol: calloc >>>>> >>>>> ... how does that even make sense when emmalloc is supposed to provide >>>>> an implementation of calloc... anyway... >>>>> >>>>> The error goes away when compiling in debug mode (some differences >>>>> that come to mind to the release mode is that debug mode doesn't use >>>>> -flto, >>>>> and also doesn't run the closure compiler). >>>>> >>>>> The problem also goes away when not building with emmalloc. >>>>> >>>>> Now the weird thing is that the entire code this sample is built from >>>>> doesn't appear to call calloc anywhere... and that other samples which >>>>> actually use calloc build just fines. >>>>> >>>>> Has anybody seen a similar problem yet, before I jump myself into the >>>>> rabbit hole? :) >>>>> >>>>> The problematic command line is: >>>>> >>>>> em++ -s DISABLE_EXCEPTION_CATCHING=1 -fno-exceptions -fno-rtti >>>>> -fstrict-aliasing -Wall -Wno-multichar -Wextra -Wno-unknown-pragmas >>>>> -Wno-ignored-qualifiers -Wno-long-long -Wno-overloaded-virtual >>>>> -Wno-deprecated-writable-strings -Wno-unused-volatile-lvalue >>>>> -Wno-inconsistent-missing-override -Wno-warn-absolute-paths >>>>> -Wno-expansion-to-defined -flto -O3 -DNDEBUG -s >>>>> DISABLE_EXCEPTION_CATCHING=1 --memory-init-file 0 -s >>>>> INITIAL_MEMORY=33554432 -s ERROR_ON_UNDEFINED_SYMBOLS=1 -s >>>>> NO_EXIT_RUNTIME=1 -s LLD_REPORT_UNDEFINED=1 -s ALLOW_MEMORY_GROWTH=1 -s >>>>> USE_WEBGL2=1 -s "MALLOC='emmalloc'" -s NO_FILESYSTEM=1 -s WASM=1 >>>>> --shell-file /Users/floh/projects/sokol-samples/webpage/shell.html -O3 >>>>> -flto --closure 1 -s ASSERTIONS=0 >>>>> sapp/CMakeFiles/spine-sapp.dir/spine-sapp.c.obj >>>>> sapp/CMakeFiles/spine-sapp.dir/spine-assets.c.obj -o >>>>> /Users/floh/projects/fips-deploy/sokol-samples/sapp-webgl2-wasm-vscode-release/spine-sapp.html >>>>> libs/sokol/libsokol.a libs/spine-c/libspine-c.a libs/stb/libstb.a >>>>> libs/util/libfileutil.a fips-cimgui_cimgui/libcimgui.a >>>>> >>>>> -- >>>>> 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 on the web visit >>>>> https://groups.google.com/d/msgid/emscripten-discuss/c47cee25-6e4b-4fbe-9f6f-0d7da7e02562n%40googlegroups.com >>>>> <https://groups.google.com/d/msgid/emscripten-discuss/c47cee25-6e4b-4fbe-9f6f-0d7da7e02562n%40googlegroups.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 on the web visit > https://groups.google.com/d/msgid/emscripten-discuss/f761c696-9943-474d-8bd8-6bccb0667f37n%40googlegroups.com > <https://groups.google.com/d/msgid/emscripten-discuss/f761c696-9943-474d-8bd8-6bccb0667f37n%40googlegroups.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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