Wasm2js: support i64 globals (#2021)

Split them into two i32 globals.

1 files changed, 43 insertions, 11 deletions

diff --git a/src/passes/I64ToI32Lowering.cpp b/src/passes/I64ToI32Lowering.cpp
index 42566c0e2..a1686d27d 100644
--- a/src/passes/I64ToI32Lowering.cpp
+++ b/src/passes/I64ToI32Lowering.cpp
@@ -36,9 +36,7 @@
 namespace wasm {
 
 static Name makeHighName(Name n) {
-  return Name(
-    cashew::IString((std::string(n.c_str()) + "$hi").c_str(), false)
-  );
+  return std::string(n.c_str()) + "$hi";
 }
 
 struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
@@ -104,12 +102,27 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     if (!builder) builder = make_unique<Builder>(*module);
     // add new globals for high bits
     for (size_t i = 0, globals = module->globals.size(); i < globals; ++i) {
-      auto& curr = module->globals[i];
+      auto* curr = module->globals[i].get();
       if (curr->type != i64) continue;
+      originallyI64Globals.insert(curr->name);
       curr->type = i32;
-      auto* high = ModuleUtils::copyGlobal(curr.get(), *module);
-      high->name = makeHighName(curr->name);
+      auto* high = builder->makeGlobal(makeHighName(curr->name), i32, builder->makeConst(Literal(int32_t(0))), Builder::Mutable);
       module->addGlobal(high);
+      if (curr->imported()) {
+        Fatal() << "TODO: imported i64 globals";
+      } else {
+        if (auto* c = curr->init->dynCast<Const>()) {
+          uint64_t value = c->value.geti64();
+          c->value = Literal(uint32_t(value));
+          c->type = i32;
+          high->init = builder->makeConst(Literal(uint32_t(value >> 32)));
+        } else if (auto* get = curr->init->dynCast<GetGlobal>()) {
+          high->init = builder->makeGetGlobal(makeHighName(get->name), i32);
+        } else {
+          WASM_UNREACHABLE();
+        }
+        curr->init->type = i32;
+      }
     }
 
     // For functions that return 64-bit values, we use this global variable
@@ -425,7 +438,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       return;
     }
     TempVar highBits = fetchOutParam(curr->value);
-    SetLocal* setHigh = builder->makeSetLocal(
+    auto* setHigh = builder->makeSetLocal(
       mappedIndex + 1,
       builder->makeGetLocal(highBits, i32)
     );
@@ -434,13 +447,30 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
   }
 
   void visitGetGlobal(GetGlobal* curr) {
-    if (curr->type != i64) return;
-    assert(false && "GetGlobal not implemented");
+    if (!getFunction()) return; // if in a global init, skip - we already handled that.
+    if (!originallyI64Globals.count(curr->name)) return;
+    curr->type = i32;
+    TempVar highBits = getTemp();
+    SetLocal *setHighBits = builder->makeSetLocal(
+      highBits,
+      builder->makeGetGlobal(
+        makeHighName(curr->name),
+        i32
+      )
+    );
+    Block* result = builder->blockify(setHighBits, curr);
+    replaceCurrent(result);
+    setOutParam(result, std::move(highBits));
   }
 
   void visitSetGlobal(SetGlobal* curr) {
-    if (curr->type != i64) return;
-    assert(false && "SetGlobal not implemented");
+    if (!originallyI64Globals.count(curr->name)) return;
+    TempVar highBits = fetchOutParam(curr->value);
+    auto* setHigh = builder->makeSetGlobal(
+      makeHighName(curr->name),
+      builder->makeGetLocal(highBits, i32)
+    );
+    replaceCurrent(builder->makeSequence(curr, setHigh));
   }
 
   void visitLoad(Load* curr) {
@@ -526,6 +556,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
   }
 
   void visitConst(Const* curr) {
+    if (!getFunction()) return; // if in a global init, skip - we already handled that.
     if (curr->type != i64) return;
     TempVar highBits = getTemp();
     Const* lowVal = builder->makeConst(
@@ -1606,6 +1637,7 @@ private:
   std::unordered_map<Expression*, TempVar> highBitVars;
   std::unordered_map<Name, TempVar> labelHighBitVars;
   std::unordered_map<Index, Type> tempTypes;
+  std::unordered_set<Name> originallyI64Globals;
   Index nextTemp;
 
   TempVar getTemp(Type ty = i32) {