wasm2js: Avoid 64-bit scratch memory helpers in wasm-intrinsics (#2926)

That code originally used memory location 1024 to save 64 bits of
data (as that is what rust does apparently). We refactored it
manually to instead use a scratch memory helper, which is safer.
However, that 64-bit function ends up legalized, which actually
changes the interface between the module and the outside,
which is confusing and causes problems with optimizations
that can remove the getTempRet0 imports, see
emscripten-core/emscripten#11456

Instead, just use a global i64 to stash those bits. This requires
adding support for copying globals from the intrinsics module,
but otherwise seems simpler overall.

1 files changed, 0 insertions, 2 deletions

diff --git a/src/asmjs/shared-constants.cpp b/src/asmjs/shared-constants.cpp
index 8a13cf55c..37594108a 100644
--- a/src/asmjs/shared-constants.cpp
+++ b/src/asmjs/shared-constants.cpp
@@ -113,8 +113,6 @@ namespace wasm2js {
 
 cashew::IString SCRATCH_LOAD_I32("wasm2js_scratch_load_i32");
 cashew::IString SCRATCH_STORE_I32("wasm2js_scratch_store_i32");
-cashew::IString SCRATCH_LOAD_I64("wasm2js_scratch_load_i64");
-cashew::IString SCRATCH_STORE_I64("wasm2js_scratch_store_i64");
 cashew::IString SCRATCH_LOAD_F32("wasm2js_scratch_load_f32");
 cashew::IString SCRATCH_STORE_F32("wasm2js_scratch_store_f32");
 cashew::IString SCRATCH_LOAD_F64("wasm2js_scratch_load_f64");