globals mutability fixes

5 files changed, 26 insertions, 6 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index bce67a582..1c528d7f3 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -177,6 +177,7 @@ private:
     else if (type == f64) value = Literal(double(0));
     else WASM_UNREACHABLE();
     global->init = wasm.allocator.alloc<Const>()->set(value);
+    global->mutable_ = true;
     wasm.addGlobal(global);
   }
 
@@ -502,9 +503,20 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
       type = WasmType::f64;
     }
     if (type != WasmType::none) {
+      // we need imported globals to be mutable, but wasm doesn't support that yet, so we must
+      // import an immutable and create a mutable global initialized to its value
+      import->name = Name(std::string(import->name.str) + "$asm2wasm$import");
       import->kind = Import::Global;
       import->globalType = type;
       mappedGlobals.emplace(name, type);
+      {
+        auto global = new Global();
+        global->name = name;
+        global->type = type;
+        global->init = builder.makeGetGlobal(import->name, type);
+        global->mutable_ = true;
+        wasm.addGlobal(global);
+      }
     } else {
       import->kind = Import::Function;
     }
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 4cb363e66..06a8758c5 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -563,7 +563,11 @@ struct PrintSExpression : public Visitor<PrintSExpression> {
   void visitGlobal(Global *curr) {
     printOpening(o, "global ");
     printName(curr->name) << ' ';
-    o << printWasmType(curr->type) << ' ';
+    if (curr->mutable_) {
+      o << "(mut " << printWasmType(curr->type) << ") ";
+    } else {
+      o << printWasmType(curr->type) << ' ';
+    }
     visit(curr->init);
     o << ')';
   }
diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index 147746c82..1bc18e687 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -1293,8 +1293,13 @@ public:
       else if (match(BinaryConsts::Section::FunctionSignatures)) readFunctionSignatures();
       else if (match(BinaryConsts::Section::Functions)) readFunctions();
       else if (match(BinaryConsts::Section::ExportTable)) readExports();
-      else if (match(BinaryConsts::Section::Globals)) readGlobals();
-      else if (match(BinaryConsts::Section::DataSegments)) readDataSegments();
+      else if (match(BinaryConsts::Section::Globals)) {
+        readGlobals();
+        // imports can read global imports, so we run getGlobalName and create the mapping
+        // but after we read globals, we need to add the internal globals too, so do that here
+        mappedGlobals.clear(); // wipe the mapping
+        getGlobalName(0); // force rebuild
+      } else if (match(BinaryConsts::Section::DataSegments)) readDataSegments();
       else if (match(BinaryConsts::Section::FunctionTable)) readFunctionTable();
       else if (match(BinaryConsts::Section::Names)) readNames();
       else {
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index b4fcd3466..6280de7d3 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -1517,8 +1517,7 @@ private:
         ex->kind = Export::Table;
       } else if (inner[0]->str() == GLOBAL) {
         ex->kind = Export::Global;
-        auto* global = wasm.getGlobal(ex->value);
-        if (global->mutable_) throw ParseException("cannot export a mutable global", s.line, s.col);
+        if (wasm.checkGlobal(ex->value) && wasm.getGlobal(ex->value)->mutable_) throw ParseException("cannot export a mutable global", s.line, s.col);
       } else {
         WASM_UNREACHABLE();
       }
diff --git a/src/wasm-validator.h b/src/wasm-validator.h
index 1d3b5c41b..6c6792228 100644
--- a/src/wasm-validator.h
+++ b/src/wasm-validator.h
@@ -335,7 +335,7 @@ public:
   }
 
   void visitGlobal(Global* curr) {
-    shouldBeTrue(curr->init->is<Const>(), curr->name, "global init must be valid");
+    shouldBeTrue(curr->init->is<Const>() || curr->init->is<GetGlobal>(), curr->name, "global init must be valid");
     shouldBeEqual(curr->type, curr->init->type, nullptr, "global init must have correct type");
   }