Add support for WASM Metadata according to new spec.

api/wasm/cpp/Makefile

@@ -0,0 +1,9 @@
+all: proxy_wasm_intrinsics.pb.h proxy_wasm_intrinsics_lite.pb.h struct_lite.pb.h
+
+proxy_wasm_intrinsics.pb.h: proxy_wasm_intrinsics.proto
+	protoc --cpp_out=. proxy_wasm_intrinsics.proto
+
+proxy_wasm_intrinsics_lite.pb.h struct_lite.pb.h: proxy_wasm_intrinsics_lite.proto
+	protoc --cpp_out=. proxy_wasm_intrinsics_lite.proto
+	protoc --cpp_out=. struct_lite.proto
+

api/wasm/cpp/Makefile.base

@@ -7,7 +7,7 @@ else
 endif
 
 %.wasm %.wat: %.cc ${API}/proxy_wasm_intrinsics.h ${API}/proxy_wasm_intrinsics.js
-	em++ -s WASM=1 -s LEGALIZE_JS_FFI=0 -s EMIT_EMSCRIPTEN_METADATA=1 --std=c++17 -O3 -g3 -I${API} --js-library ${API}/proxy_wasm_intrinsics.js $*.cc ${CONTEXT_LIB} -o $*.js
+	em++ -s WASM=1 -s LEGALIZE_JS_FFI=0 -s EMIT_EMSCRIPTEN_METADATA=1 --std=c++17 -O3 -g3 -I${API} -I/usr/local/include --js-library ${API}/proxy_wasm_intrinsics.js $*.cc ${API}/proxy_wasm_intrinsics.pb.cc ${CONTEXT_LIB} ${API}/libprotobuf.bc -o $*.js
 	wavm-disas $*.wasm $*.wat
 	wavm-compile $*.wasm $*.wasm
 	rm -f $*.js $*.wast

api/wasm/cpp/Makefile.base_lite

@@ -0,0 +1,17 @@
+API:=$(shell git rev-parse --show-toplevel)/api/wasm/cpp
+
+ifdef NO_CONTEXT
+  CONTEXT_LIB =
+else
+  CONTEXT_LIB = ${API}/proxy_wasm_intrinsics.cc
+endif
+
+%.wasm %.wat: %.cc ${API}/proxy_wasm_intrinsics.h ${API}/proxy_wasm_intrinsics.js
+	em++ -s WASM=1 -s LEGALIZE_JS_FFI=0 -s EMIT_EMSCRIPTEN_METADATA=1 --std=c++17 -O3 -g3 -DEMSCRIPTEN_PROTOBUF_LITE=1 -I${API} -I${API}/google/protobuf -I/usr/local/include --js-library ${API}/proxy_wasm_intrinsics.js $*.cc ${API}/proxy_wasm_intrinsics_lite.pb.cc ${API}/struct_lite.pb.cc ${CONTEXT_LIB} ${API}/libprotobuf-lite.bc -o $*.js
+	wavm-disas $*.wasm $*.wat
+	wavm-compile $*.wasm $*.wasm
+	rm -f $*.js $*.wast
+	chmod 644 $*.wat
+
+clean:
+	rm *.wasm *.wat

api/wasm/cpp/README.md

@@ -0,0 +1,7 @@
+Dependencies for building WASM modules:
+
+- You must install the version of protobuf on your build system that matches the libprotobuf.bc files (without any patches) so that the generated code matches the .bc library.
+  Currently this is based on tag v3.6.1 of https://github.com/protocolbuffers/protobuf.
+
+- If want to rebuild the .bc files or use a different version see the instructions at https://github.com/kwonoj/protobuf-wasm  (note: this is pinned to git tag v3.6.1)
+  A pre-patched repo is available at https://github.com/jplevyak/protobuf branch envoy-wasm