wasm2js: Bulk memory support (#2923)

Adds a special helper functions for data.drop etc., as unlike most
wasm instructions these are too big to emit inline.

Track passive segments at runtime in var memorySegments
whose indexes are the segment indexes.

Emit var bufferView even if the memory exists even without
memory segments, as we do still need the view in order to
operate on it.

Also adds a few constants for atomics that will be useful in future
PRs (as this PR updates the constant lists anyhow).

1 files changed, 29 insertions, 7 deletions

diff --git a/src/abi/js.h b/src/abi/js.h
index de74899b6..c8ac94407 100644
--- a/src/abi/js.h
+++ b/src/abi/js.h
@@ -44,14 +44,21 @@ extern cashew::IString SCRATCH_LOAD_F32;
 extern cashew::IString SCRATCH_STORE_F32;
 extern cashew::IString SCRATCH_LOAD_F64;
 extern cashew::IString SCRATCH_STORE_F64;
+extern cashew::IString MEMORY_INIT;
+extern cashew::IString MEMORY_FILL;
+extern cashew::IString MEMORY_COPY;
+extern cashew::IString DATA_DROP;
+extern cashew::IString ATOMIC_WAIT_I32;
+extern cashew::IString ATOMIC_RMW_I64;
+extern cashew::IString GET_STASHED_BITS;
 
-// The wasm2js scratch memory helpers let us read and write to scratch memory
-// for purposes of implementing things like reinterpret, etc.
+// The wasm2js helpers let us do things that can't be done without special help,
+// like read and write to scratch memory for purposes of implementing things
+// like reinterpret, etc.
 // The optional "specific" parameter is a specific function we want. If not
 // provided, we create them all.
-inline void
-ensureScratchMemoryHelpers(Module* wasm,
-                           cashew::IString specific = cashew::IString()) {
+inline void ensureHelpers(Module* wasm,
+                          cashew::IString specific = cashew::IString()) {
   auto ensureImport = [&](Name name, Type params, Type results) {
     if (wasm->getFunctionOrNull(name)) {
       return;
@@ -75,13 +82,28 @@ ensureScratchMemoryHelpers(Module* wasm,
   ensureImport(SCRATCH_STORE_F32, {Type::f32}, Type::none);
   ensureImport(SCRATCH_LOAD_F64, {}, Type::f64);
   ensureImport(SCRATCH_STORE_F64, {Type::f64}, Type::none);
+  ensureImport(
+    MEMORY_INIT, {Type::i32, Type::i32, Type::i32, Type::i32}, Type::none);
+  ensureImport(MEMORY_FILL, {Type::i32, Type::i32, Type::i32}, Type::none);
+  ensureImport(MEMORY_COPY, {Type::i32, Type::i32, Type::i32}, Type::none);
+  ensureImport(DATA_DROP, {Type::i32}, Type::none);
+  ensureImport(
+    ATOMIC_WAIT_I32, {Type::i32, Type::i32, Type::i32, Type::i32}, Type::i32);
+  ensureImport(
+    ATOMIC_RMW_I64,
+    {Type::i32, Type::i32, Type::i32, Type::i32, Type::i32, Type::i32},
+    Type::i32);
+  ensureImport(GET_STASHED_BITS, {}, Type::i32);
 }
 
-inline bool isScratchMemoryHelper(cashew::IString name) {
+inline bool isHelper(cashew::IString name) {
   return name == SCRATCH_LOAD_I32 || name == SCRATCH_STORE_I32 ||
          name == SCRATCH_LOAD_I64 || name == SCRATCH_STORE_I64 ||
          name == SCRATCH_LOAD_F32 || name == SCRATCH_STORE_F32 ||
-         name == SCRATCH_LOAD_F64 || name == SCRATCH_STORE_F64;
+         name == SCRATCH_LOAD_F64 || name == SCRATCH_STORE_F64 ||
+         name == ATOMIC_WAIT_I32 || name == MEMORY_INIT ||
+         name == MEMORY_FILL || name == MEMORY_COPY || name == DATA_DROP ||
+         name == ATOMIC_RMW_I64 || name == GET_STASHED_BITS;
 }
 
 } // namespace wasm2js