wasm2js: emscripten glue option (#2000)

Add a wasm2js option for the glue to be in emscripten-compatible format (as opposed to ES6). This does a few things so far:

* Emit START_FUNCTIONS, END_FUNCTIONS markers in the code, for future use in the optimizer.
* Emit the glue as a function to be called from emscripten.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/tools/wasm2js.cpp b/src/tools/wasm2js.cpp
index 76a724f86..8704dbf49 100644
--- a/src/tools/wasm2js.cpp
+++ b/src/tools/wasm2js.cpp
@@ -370,6 +370,11 @@ int main(int argc, const char *argv[]) {
            [&](Options* o, const std::string& argument) {
              flags.pedantic = true;
            })
+      .add("--emscripten", "", "Emulate the glue in emscripten-compatible form (and not ES6 module form)",
+           Options::Arguments::Zero,
+           [&](Options* o, const std::string& argument) {
+             flags.emscripten = true;
+           })
       .add_positional("INFILE", Options::Arguments::One,
                       [](Options *o, const std::string& argument) {
                         o->extra["infile"] = argument;