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 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 Signed-off-by: Kohei Tokunaga <ktokunaga.m...@gmail.com> --- include/qemu/cacheflush.h | 7 +++++++ util/cacheflush.c | 4 ++++ 2 files changed, 11 insertions(+) V2: - Added an explanation for the change to both the code comment and the commit message. diff --git a/include/qemu/cacheflush.h b/include/qemu/cacheflush.h index ae20bcda73..76eb55d818 100644 --- a/include/qemu/cacheflush.h +++ b/include/qemu/cacheflush.h @@ -26,6 +26,13 @@ static inline void flush_idcache_range(uintptr_t rx, uintptr_t rw, size_t len) /* icache is coherent and does not require flushing. */ } +#elif defined(EMSCRIPTEN) + +static inline void flush_idcache_range(uintptr_t rx, uintptr_t rw, size_t len) +{ + /* Wasm doesn't have executable region of memory. */ +} + #else void flush_idcache_range(uintptr_t rx, uintptr_t rw, size_t len); diff --git a/util/cacheflush.c b/util/cacheflush.c index 1d12899a39..17c58918de 100644 --- a/util/cacheflush.c +++ b/util/cacheflush.c @@ -229,6 +229,10 @@ static void __attribute__((constructor)) init_cache_info(void) /* Caches are coherent and do not require flushing; symbol inline. */ +#elif defined(EMSCRIPTEN) + +/* Wasm doesn't have executable region of memory. */ + #elif defined(__aarch64__) && !defined(CONFIG_WIN32) /* * For Windows, we use generic implementation of flush_idcache_range, that -- 2.25.1
