webassembly/api: Allow specifying the pystack size.

This allows increasing the Python recursion depth if needed.

Also increase the default to 2k words.  There is enough RAM in the
browser/node context for this to be increased, and having a larger pystack
allows more complex code to run without hitting the limit.

Signed-off-by: Damien George <damien@micropython.org>

ports/webassembly/api.js

@@ -25,6 +25,7 @@
  */
 
 // Options:
+// - pystack: size in words of the MicroPython Python stack.
 // - heapsize: size in bytes of the MicroPython GC heap.
 // - url: location to load `micropython.mjs`.
 // - stdin: function to return input characters.
@@ -34,10 +35,11 @@
 // - stderr: same behaviour as stdout but for error output.
 // - linebuffer: whether to buffer line-by-line to stdout/stderr.
 export async function loadMicroPython(options) {
-    const { heapsize, url, stdin, stdout, stderr, linebuffer } = Object.assign(
-        { heapsize: 1024 * 1024, linebuffer: true },
-        options,
-    );
+    const { pystack, heapsize, url, stdin, stdout, stderr, linebuffer } =
+        Object.assign(
+            { pystack: 2 * 1024, heapsize: 1024 * 1024, linebuffer: true },
+            options,
+        );
     let Module = {};
     Module.locateFile = (path, scriptDirectory) =>
         url || scriptDirectory + path;
@@ -96,7 +98,12 @@ export async function loadMicroPython(options) {
         );
         return proxy_convert_mp_to_js_obj_jsside_with_free(value);
     };
-    Module.ccall("mp_js_init", "null", ["number"], [heapsize]);
+    Module.ccall(
+        "mp_js_init",
+        "null",
+        ["number", "number"],
+        [pystack, heapsize],
+    );
     Module.ccall("proxy_c_init", "null", [], []);
     return {
         _module: Module,

ports/webassembly/main.c

@@ -66,7 +66,12 @@ void external_call_depth_dec(void) {
     --external_call_depth;
 }
 
-void mp_js_init(int heap_size) {
+void mp_js_init(int pystack_size, int heap_size) {
+    #if MICROPY_ENABLE_PYSTACK
+    mp_obj_t *pystack = (mp_obj_t *)malloc(pystack_size * sizeof(mp_obj_t));
+    mp_pystack_init(pystack, pystack + pystack_size);
+    #endif
+
     #if MICROPY_ENABLE_GC
     char *heap = (char *)malloc(heap_size * sizeof(char));
     gc_init(heap, heap + heap_size);
@@ -80,11 +85,6 @@ void mp_js_init(int heap_size) {
     MP_STATE_MEM(gc_alloc_threshold) = 16 * 1024 / MICROPY_BYTES_PER_GC_BLOCK;
     #endif
 
-    #if MICROPY_ENABLE_PYSTACK
-    static mp_obj_t pystack[1024];
-    mp_pystack_init(pystack, &pystack[MP_ARRAY_SIZE(pystack)]);
-    #endif
-
     mp_init();
 
     #if MICROPY_VFS_POSIX

tests/ports/webassembly/heap_expand.mjs.exp

@@ -17,11 +17,11 @@
 135109888
 134978800
 134716640
-135216848
-136217216
-138218032
-142219616
-150222864
+135216784
+136217152
+138217840
+142219296
+150222224
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