03d45f1d62
Implement spec reference-types proposal for interpreter, AOT and JIT, update documents and add sample. And upgrade AOT_CURRENT_VERSION to 3 as AOT file format and AOT module instance layout are changed. Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>
1.6 KiB
WAMR reference-types introduction
WebAssembly reference-types proposal introduces the new type externref and makes it easier and more efficient to interoperate with host environment, allowing host references to be represented directly by type externref. And WASM modules can talk about host references directly, rather than requiring external glue code running in the host.
WAMR implements the reference-types proposal, allowing developer to pass the host object to WASM application and then restore and access the host object in native lib. In WAMR internal, the external host object is represented as externref index with uint32 type, developer must firstly map the host object of void * type to the externref index, and then pass the index to the function to called as the function's externref argument.
Currently WAMR provides APIs as below:
bool
wasm_externref_obj2ref(wasm_module_inst_t module_inst,
void *extern_obj, uint32_t *p_externref_idx);
WASM_RUNTIME_API_EXTERN bool
wasm_externref_ref2obj(uint32_t externref_idx, void **p_extern_obj);
WASM_RUNTIME_API_EXTERN bool
wasm_externref_retain(uint32 externref_idx);
The wasm_externref_obj2ref() API is used to map the host object to the externref index, and the wasm_externref_ref2obj() API is used to retrieve the original host object mapped. The wasm_externref_retain() API is to retain the host object if we don't want the object to be cleaned when it isn't used during externref object reclaim.
Please ref to the sample for more details.