Remove no longer needed Emscripten metadata. (#70)

Signed-off-by: Piotr Sikora <piotrsikora@google.com>

Author: PiotrSikora

include/proxy-wasm/wasm.h

@@ -124,20 +124,6 @@ class WasmBase : public std::enable_shared_from_this<WasmBase> {
 
   AbiVersion abiVersion() { return abi_version_; }
 
-  bool getEmscriptenVersion(uint32_t *emscripten_metadata_major_version,
-                            uint32_t *emscripten_metadata_minor_version,
-                            uint32_t *emscripten_abi_major_version,
-                            uint32_t *emscripten_abi_minor_version) {
-    if (!is_emscripten_) {
-      return false;
-    }
-    *emscripten_metadata_major_version = emscripten_metadata_major_version_;
-    *emscripten_metadata_minor_version = emscripten_metadata_minor_version_;
-    *emscripten_abi_major_version = emscripten_abi_major_version_;
-    *emscripten_abi_minor_version = emscripten_abi_minor_version_;
-    return true;
-  }
-
   void addAfterVmCallAction(std::function<void()> f) { after_vm_call_actions_.push_back(f); }
   void doAfterVmCallActions() {
     // NB: this may be deleted by a delayed function unless prevented.
@@ -243,13 +229,6 @@ class WasmBase : public std::enable_shared_from_this<WasmBase> {
   // ABI version.
   AbiVersion abi_version_ = AbiVersion::Unknown;
 
-  bool is_emscripten_ = false;
-  uint32_t emscripten_metadata_major_version_ = 0;
-  uint32_t emscripten_metadata_minor_version_ = 0;
-  uint32_t emscripten_abi_major_version_ = 0;
-  uint32_t emscripten_abi_minor_version_ = 0;
-  uint32_t emscripten_standalone_wasm_ = 0;
-
   // Plugin Stats/Metrics
   uint32_t next_counter_metric_id_ = static_cast<uint32_t>(MetricType::Counter);
   uint32_t next_gauge_metric_id_ = static_cast<uint32_t>(MetricType::Gauge);

src/wasm.cc

@@ -44,22 +44,6 @@ std::unordered_map<std::string, WasmForeignFunction> *foreign_functions = nullpt
 
 const std::string INLINE_STRING = "<inline>";
 
-const uint8_t *decodeVarint(const uint8_t *pos, const uint8_t *end, uint32_t *out) {
-  uint32_t ret = 0;
-  int shift = 0;
-  while (pos < end && (*pos & 0x80)) {
-    ret |= (*pos & 0x7f) << shift;
-    shift += 7;
-    pos++;
-  }
-  if (pos < end) {
-    ret |= *pos << shift;
-    pos++;
-  }
-  *out = ret;
-  return pos;
-}
-
 std::string Sha256(std::string_view data) {
   std::vector<unsigned char> hash(picosha2::k_digest_size);
   picosha2::hash256(data.begin(), data.end(), hash.begin(), hash.end());
@@ -302,36 +286,6 @@ bool WasmBase::initialize(const std::string &code, bool allow_precompiled) {
     if (!ok) {
       return false;
     }
-    auto metadata = wasm_vm_->getCustomSection("emscripten_metadata");
-    if (!metadata.empty()) {
-      // See https://github.com/emscripten-core/emscripten/blob/incoming/tools/shared.py#L3059
-      is_emscripten_ = true;
-      auto start = reinterpret_cast<const uint8_t *>(metadata.data());
-      auto end = reinterpret_cast<const uint8_t *>(metadata.data() + metadata.size());
-      start = decodeVarint(start, end, &emscripten_metadata_major_version_);
-      start = decodeVarint(start, end, &emscripten_metadata_minor_version_);
-      start = decodeVarint(start, end, &emscripten_abi_major_version_);
-      start = decodeVarint(start, end, &emscripten_abi_minor_version_);
-      uint32_t temp;
-      if (emscripten_metadata_major_version_ > 0 || emscripten_metadata_minor_version_ > 1) {
-        // metadata 0.2 - added: wasm_backend.
-        start = decodeVarint(start, end, &temp);
-      }
-      start = decodeVarint(start, end, &temp);
-      start = decodeVarint(start, end, &temp);
-      if (emscripten_metadata_major_version_ > 0 || emscripten_metadata_minor_version_ > 0) {
-        // metadata 0.1 - added: global_base, dynamic_base, dynamictop_ptr and tempdouble_ptr.
-        start = decodeVarint(start, end, &temp);
-        start = decodeVarint(start, end, &temp);
-        start = decodeVarint(start, end, &temp);
-        decodeVarint(start, end, &temp);
-        if (emscripten_metadata_major_version_ > 0 || emscripten_metadata_minor_version_ > 2) {
-          // metadata 0.3 - added: standalone_wasm.
-          start = decodeVarint(start, end, &emscripten_standalone_wasm_);
-        }
-      }
-    }
-
     code_ = code;
     allow_precompiled_ = allow_precompiled;
   }