mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-07-09 20:35:26 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 11

gh-128627: Emscripten: Fix address calculation for wasm-gc trampoline (#128782)

Browse source 
Modifies the memory calculation to divide the entire memory address by 4, not just the base address.
This commit is contained in:
Hood Chatham 2025-01-23 00:02:04 +00:00 • committed by GitHub
parent 298dda5770
commit 960936fe90
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
3 changed files with 9 additions and 11 deletions
Download patch file Download diff file Expand all files Collapse all files

16
Python/emscripten_trampoline.c
View file

@ -26,11 +26,9 @@ EM_JS(CountArgsFunc, _PyEM_GetCountArgsPtr, (), {
// Binary module for the checks. It has to be done in web assembly because
// clang/llvm have no support yet for the reference types yet. In fact, the wasm
// binary toolkit doesn't yet support the ref.test instruction either. To
// convert the following module to the binary, my approach is to find and
// replace "ref.test $type" -> "drop i32.const n" on the source text. This
// results in the bytes "0x1a, 0x41, n" where we need the bytes "0xfb, 0x14, n"
// so doing a find and replace on the output from "0x1a, 0x41" -> "0xfb, 0x14"
// gets us the output we need.
// convert the following textual wasm to a binary, you can build wabt from this
// branch: https://github.com/WebAssembly/wabt/pull/2529 and then use that
// wat2wasm binary.
//
// (module
// (type $type0 (func (param) (result i32)))
@ -154,15 +152,15 @@ addOnPreRun(() => {
let ptr = 0;
try {
const mod = new WebAssembly.Module(code);
const inst = new WebAssembly.Instance(mod, {e: {t: wasmTable}});
const inst = new WebAssembly.Instance(mod, { e: { t: wasmTable } });
ptr = addFunction(inst.exports.f);
} catch(e) {
} catch (e) {
// If something goes wrong, we'll null out _PyEM_CountFuncParams and fall
// back to the JS trampoline.
}
Module._PyEM_CountArgsPtr = ptr;
const offset = HEAP32[__PyEM_EMSCRIPTEN_COUNT_ARGS_OFFSET/4];
HEAP32[__PyRuntime/4 + offset] = ptr;
const offset = HEAP32[__PyEM_EMSCRIPTEN_COUNT_ARGS_OFFSET / 4];
HEAP32[(__PyRuntime + offset) / 4] = ptr;
});
);