Hi Philippe, >On 22/4/25 07:27, Kohei Tokunaga wrote: >> Although __builtin___clear_cache is used to flush the instruction cache for >> a specified memory region[1], this operation doesn't apply to wasm, as its >> memory isn't executable. Moreover, Emscripten does not support this builtin >> and fails to compile it with the following error. >> >>> fatal error: error in backend: llvm.clear_cache is not supported on wasm > >Note, you mix LLVM error ... > >> >> To resolve this, this commit removes the call to __builtin___clear_cache for >> Emscripten build. >> >> [1] https://gcc.gnu.org/onlinedocs/gcc-14.2.0/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005f_005f_005fclear_005fcache > >... with this GCC documentation: > > If the target does not require instruction cache flushes, > __builtin___clear_cache has no effect. > >I'd expect __builtin___clear_cache() to be OK, having no effect on a GCC >WASM implementation.
Thank you for the feedback. Although Emscripten supports built-in functions using GCC-compatible syntax, the corner-case behavior looks different from what's described in the GCC documentation, as shown in this patch. To avoid the confusion, I'll remove that link in the next version of the patch series.
