start to sketch out interpreter/js

1 files changed, 63 insertions, 0 deletions

diff --git a/src/wasm-js.cpp b/src/wasm-js.cpp
index ccc589485..e2ef47bbb 100644
--- a/src/wasm-js.cpp
+++ b/src/wasm-js.cpp
@@ -1,4 +1,67 @@
 
+//
+// wasm intepreter for asm2wasm output, in a js environment. receives asm.js,
+// generates a runnable module suitable as a polyfill.
+//
+
+#include <emscripten.h>
+
+#include "asm2wasm.h"
 #include "wasm-interpreter.h"
 
+using namespace cashew;
+using namespace wasm;
+
+// receives asm.js code, parses into wasm and returns an instance handle.
+// this creates a module, an external interface, and a module instance,
+// all of which are then the responsibility of the caller to free.
+// note: this modifies the input.
+extern "C" ModuleInstance* EMSCRIPTEN_KEEPALIVE load_asm(char *input) {
+  // emcc --separate-asm modules look like
+  //
+  //    Module["asm"] = (function(global, env, buffer) {
+  //      ..
+  //    });
+  //
+  // we need to clean that up.
+  size_t num = strlen(input);
+  assert(*input == 'M');
+  while (*input != 'f') {
+    input++;
+    num--;
+  }
+  char *end = input + num - 1;
+  while (*end != '}') {
+    *end = 0;
+    end--;
+  }
+
+  if (debug) std::cerr << "parsing...\n";
+  cashew::Parser<Ref, DotZeroValueBuilder> builder;
+  Ref asmjs = builder.parseToplevel(input);
+
+  Module* wasm = new Module();
+
+  if (debug) std::cerr << "wasming...\n";
+  Asm2WasmBuilder asm2wasm(*wasm);
+  asm2wasm.processAsm(asmjs);
+
+  if (debug) std::cerr << "optimizing...\n";
+  asm2wasm.optimize();
+
+  if (debug) std::cerr << "returning instance.\n";
+
+  struct JSExternalInterface : ModuleInstance::ExternalInterface {
+    Literal callImport(Import *import, ModuleInstance::LiteralList& arguments) override {
+    }
+
+    Literal load(Load* load, Literal ptr) override {
+    }
+
+    Literal store(Store* store, Literal ptr, Literal value) override {
+    }
+  };
+
+  return new ModuleInstance(*wasm, new JSExternalInterface());
+}