Remove the WASM WAVM ast2wasm Emscript support module and add tests. (STACKED on wasm globals support PR)

source/extensions/common/wasm/wavm/wavm.cc

@@ -240,7 +240,6 @@ Wavm::~Wavm() {
   moduleInstance_ = nullptr;
   if (emscriptenInstance_) {
     emscriptenInstance_->env = nullptr;
-    emscriptenInstance_->asm2wasm = nullptr;
     emscriptenInstance_->global = nullptr;
     emscriptenInstance_->emscriptenMemory = nullptr;
     delete emscriptenInstance_;
@@ -306,7 +305,6 @@ void Wavm::link(absl::string_view name, bool needs_emscripten) {
   if (needs_emscripten) {
     emscriptenInstance_ = Emscripten::instantiate(compartment_, irModule_);
     rootResolver.moduleNameToInstanceMap().set("env", emscriptenInstance_->env);
-    rootResolver.moduleNameToInstanceMap().set("asm2wasm", emscriptenInstance_->asm2wasm);
   }
   WAVM::Runtime::LinkResult linkResult = linkModule(irModule_, rootResolver);
   moduleInstance_ = instantiateModule(compartment_, module_, std::move(linkResult.resolvedImports),

test/extensions/wasm/test_data/Makefile

@@ -1,5 +1,5 @@
 NO_CONTEXT = true
 
-all: logging.wasm bad_signature.wasm segv.wasm emscript.wasm
+all: logging.wasm bad_signature.wasm segv.wasm emscript.wasm asm2wasm.wasm
 
 include ../../../../api/wasm/cpp/Makefile.base

test/extensions/wasm/test_data/asm2wasm.cc

@@ -0,0 +1,19 @@
+// NOLINT(namespace-envoy)
+#include <math.h>
+
+#include <string>
+
+#include "proxy_wasm_intrinsics.h"
+
+//  Use global variables so the compiler cannot optimize the operations away.
+int32_t i32a = 0;
+int32_t i32b = 1;
+double f64a = 0.0;
+double f64b = 1.0;
+
+// Emscripten in some modes and versions would use functions from the asm2wasm module to implement
+// these operations: int32_t % /, double conversion to int32_t and remainder().
+extern "C" EMSCRIPTEN_KEEPALIVE void proxy_onStart() {
+  logInfo(std::string("out ") + std::to_string(i32a / i32b) + " " + std::to_string(i32a % i32b) +
+          " " + std::to_string((int32_t)remainder(f64a, f64b)));
+}

test/extensions/wasm/wasm_test.cc

@@ -156,6 +156,31 @@ TEST(WasmTest, IntrinsicGlobals) {
   wasm->start();
 }
 
+// The asm2wasm.wasm file uses operations which would require the asm2wasm Emscripten module *if*
+// em++ is invoked with the trap mode "clamp". See
+// https://emscripten.org/docs/compiling/WebAssembly.html This test demonstrates that the asm2wasm
+// module is not required with the trap mode is set to "allow". Note: future WASM standards will
+// change this behavior by providing non-trapping instructions, but in the mean time we support the
+// default Emscripten behavior.
+TEST(WasmTest, Asm2Wasm) {
+  Stats::IsolatedStoreImpl stats_store;
+  Api::ApiPtr api = Api::createApiForTest(stats_store);
+  Upstream::MockClusterManager cluster_manager;
+  Event::SimulatedTimeSystem time_system;
+  Event::DispatcherImpl dispatcher(time_system, *api);
+  auto wasm = std::make_shared<Extensions::Common::Wasm::Wasm>("envoy.wasm.vm.wavm", "", "",
+                                                               cluster_manager, dispatcher);
+  EXPECT_NE(wasm, nullptr);
+  const auto code = TestEnvironment::readFileToStringForTest(TestEnvironment::substitute(
+      "{{ test_rundir }}/test/extensions/wasm/test_data/asm2wasm.wasm"));
+  EXPECT_FALSE(code.empty());
+  auto context = std::make_unique<TestContext>(wasm.get());
+  EXPECT_CALL(*context, scriptLog(spdlog::level::info, Eq("out 0 0 0")));
+  EXPECT_TRUE(wasm->initialize(code, "<test>", false));
+  wasm->setGeneralContext(std::move(context));
+  wasm->start();
+}
+
 } // namespace Wasm
 } // namespace Extensions
 } // namespace Envoy