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Implement module instance context APIs (#2436)

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Introduce module instance context APIs which can set one or more contexts created
by the embedder for a wasm module instance:
```C
    wasm_runtime_create_context_key
    wasm_runtime_destroy_context_key
    wasm_runtime_set_context
    wasm_runtime_set_context_spread
    wasm_runtime_get_context
```

And make libc-wasi use it and set wasi context as the first context bound to the wasm
module instance.

Also add samples.

Refer to https://github.com/bytecodealliance/wasm-micro-runtime/issues/2460.
This commit is contained in:
YAMAMOTO Takashi
2023-09-07 15:54:11 +09:00
committed by GitHub
parent af2f3c8759
commit 6c846acc59
35 changed files with 1190 additions and 56 deletions
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68
core/iwasm/include/wasm_export.h
View File

@ -1456,6 +1456,74 @@ WASM_RUNTIME_API_EXTERN void
wasm_runtime_set_enlarge_mem_error_callback(
const enlarge_memory_error_callback_t callback);
/*
* module instance context APIs
* wasm_runtime_create_context_key
* wasm_runtime_destroy_context_key
* wasm_runtime_set_context
* wasm_runtime_set_context_spread
* wasm_runtime_get_context
*
* This set of APIs is intended to be used by an embedder which provides
* extra sets of native functions, which need per module instance state
* and are maintained outside of the WAMR tree.
*
* It's modelled after the pthread specific API.
*
* wasm_runtime_set_context_spread is similar to
* wasm_runtime_set_context, except that
* wasm_runtime_set_context_spread applies the change
* to all threads in the cluster.
* It's an undefined behavior if multiple threads in a cluster call
* wasm_runtime_set_context_spread on the same key
* simultaneously. It's a caller's resposibility to perform necessary
* serialization if necessary. For example:
*
* if (wasm_runtime_get_context(inst, key) == NULL) {
* newctx = alloc_and_init(...);
* lock(some_lock);
* if (wasm_runtime_get_context(inst, key) == NULL) {
* // this thread won the race
* wasm_runtime_set_context_spread(inst, key, newctx);
* newctx = NULL;
* }
* unlock(some_lock);
* if (newctx != NULL) {
* // this thread lost the race, free it
* cleanup_and_free(newctx);
* }
* }
*
* Note: dynamic key create/destroy while instances are live is not
* implemented as of writing this.
* it's caller's resposibility to ensure destorying all module instances
* before calling wasm_runtime_create_context_key or
* wasm_runtime_destroy_context_key.
* otherwise, it's an undefined behavior.
*
* Note about threads:
* - When spawning a thread, the contexts (the pointers given to
* wasm_runtime_set_context) are copied from the parent
* instance.
* - The destructor is called only on the main instance.
*/
WASM_RUNTIME_API_EXTERN void *
wasm_runtime_create_context_key(
void (*dtor)(wasm_module_inst_t inst, void *ctx));
WASM_RUNTIME_API_EXTERN void
wasm_runtime_destroy_context_key(void *key);
WASM_RUNTIME_API_EXTERN void
wasm_runtime_set_context(wasm_module_inst_t inst, void *key,
void *ctx);
WASM_RUNTIME_API_EXTERN void
wasm_runtime_set_context_spread(wasm_module_inst_t inst, void *key,
void *ctx);
WASM_RUNTIME_API_EXTERN void *
wasm_runtime_get_context(wasm_module_inst_t inst, void *key);
/* clang-format on */
#ifdef __cplusplus