refactorings and begin interpreter

1 files changed, 95 insertions, 0 deletions

diff --git a/src/wasm-interpreter.cpp b/src/wasm-interpreter.cpp
new file mode 100644
index 000000000..8e1294624
--- /dev/null
+++ b/src/wasm-interpreter.cpp
@@ -0,0 +1,95 @@
+
+// Simple WebAssembly interpreter, designed to be embeddable in JavaScript, so it
+// can function as a polyfill.
+
+#include "wasm.h"
+
+namespace wasm {
+
+// An instance of a WebAssembly module
+class ModuleInstance {
+public:
+  ModuleInstance(Module& wasm) : wasm(wasm) {
+    for (auto function : wasm.functions) {
+      functions[function->name] = function;
+    }
+  }
+
+  Literal callFunction(const char *name) {
+    return callFunction(IString(name));
+  }
+
+  Literal callFunction(IString name) {
+    // Stuff that flows around during executing expressions: a literal, or a change in control flow
+    class Flow : public Literal {
+    public:
+      IString breakTo; // if non-null, a break is going on
+    };
+
+    // Execute a statement
+    class ExpressionRunner : public WasmVisitor<Flow> {
+      virtual Flow visitBlock(Block *curr) {
+        Flow flow;
+        for (auto expression : curr->list) {
+          flow = visit(expression);
+          if (flow.breakTo) {
+            if (flow.breakTo == curr->name) {
+              flow.breakTo.clear();
+            }
+            return flow;
+          }
+        }
+        return flow;
+      }
+      virtual Flow visitIf(If *curr)  {
+      }
+      virtual Flow visitLoop(Loop *curr)  {
+      }
+      virtual Flow visitLabel(Label *curr)  {
+      }
+      virtual Flow visitBreak(Break *curr)  {
+      }
+      virtual Flow visitSwitch(Switch *curr)  {
+      }
+      virtual Flow visitCall(Call *curr)  {
+      }
+      virtual Flow visitCallImport(CallImport *curr)  {
+      }
+      virtual Flow visitCallIndirect(CallIndirect *curr)  {
+      }
+      virtual Flow visitGetLocal(GetLocal *curr)  {
+      }
+      virtual Flow visitSetLocal(SetLocal *curr)  {
+      }
+      virtual Flow visitLoad(Load *curr)  {
+      }
+      virtual Flow visitStore(Store *curr)  {
+      }
+      virtual Flow visitConst(Const *curr)  {
+      }
+      virtual Flow visitUnary(Unary *curr)  {
+      }
+      virtual Flow visitBinary(Binary *curr)  {
+      }
+      virtual Flow visitCompare(Compare *curr)  {
+      }
+      virtual Flow visitConvert(Convert *curr)  {
+      }
+      virtual Flow visitHost(Host *curr)  {
+      }
+      virtual Flow visitNop(Nop *curr)  {
+      }
+    };
+
+    return ExpressionRunner().visit(functions[name]->body);
+  }
+
+private:
+  Module& wasm;
+
+  std::map<IString, Function*> functions;
+
+};
+
+} // namespace wasm
+