Add Exception handling and test for divide by zero exception.

ci/build_container/build_recipes/wavm.sh

@@ -31,8 +31,8 @@ cp -pR include/ "$THIRDPARTY_BUILD"/lib/llvm-6.0/include/
 
 # WAVM.
 
-COMMIT=69d647ecf6d355921b79a58aa6b1d674a76b4c2b # 2019-01-24
-SHA256=b0789161eb96cc0695cda6e0ea0b2db0bd1919795cebf5d139d66a173234d301
+COMMIT=275e15fff5928d5cac3b8c5410c5a3b3fa7168ac  # Wed Feb 20 16:13:27 2019 -0500
+SHA256=1e8306322c7de31ecb6cceb198ff1a3f37e31702402235f242a4daf68b54242f
 
 curl https://github.com/WAVM/WAVM/archive/"$COMMIT".tar.gz -sLo WAVM-"$COMMIT".tar.gz \
   && echo "$SHA256" WAVM-"$COMMIT".tar.gz | sha256sum --check

source/extensions/common/wasm/wasm.cc

@@ -440,6 +440,7 @@ uint32_t httpCallHandler(void* raw_context, uint32_t uri_ptr, uint32_t uri_size,
 
 uint32_t getTotalMemoryHandler(void*) { return 0x7FFFFFFF; }
 uint32_t _emscripten_get_heap_sizeHandler(void*) { return 0x7FFFFFFF; }
+void _llvm_trapHandler(void*) { throw WasmException("emscripten llvm_trap"); }
 
 void setTickPeriodMillisecondsHandler(void* raw_context, uint32_t tick_period_milliseconds) {
   WASM_CONTEXT(raw_context)->setTickPeriod(std::chrono::milliseconds(tick_period_milliseconds));
@@ -938,6 +939,7 @@ Wasm::Wasm(absl::string_view vm, absl::string_view id, absl::string_view initial
 #define _REGISTER(_fn) registerCallback(wasm_vm_.get(), #_fn, &_fn##Handler);
     _REGISTER(getTotalMemory);
     _REGISTER(_emscripten_get_heap_size);
+    _REGISTER(_llvm_trap);
 #undef _REGISTER
 
     // Calls with the "_proxy_" prefix.

source/extensions/common/wasm/wasm.h

@@ -306,7 +306,7 @@ class Wasm : public Envoy::Server::Wasm,
   uint32_t next_context_id_ = 0;
   std::unique_ptr<WasmVm> wasm_vm_;
   std::shared_ptr<Context> general_context_; // Context unrelated to any specific stream.
-  std::function<void(Context*)> tick_;
+  std::function<void(Common::Wasm::Context*)> tick_;
   std::chrono::milliseconds tick_period_;
   Event::TimerPtr timer_;
 

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

@@ -73,13 +73,26 @@ struct SaveRestoreContext {
 #define CALL_WITH_CONTEXT(_x, _context)                                                            \
   do {                                                                                             \
     SaveRestoreContext _saved_context(static_cast<Context*>(_context));                            \
-    _x;                                                                                            \
+    WAVM::Runtime::catchRuntimeExceptions([&] { _x; },                                             \
+                                          [&](WAVM::Runtime::Exception* exception) {               \
+                                            auto description = describeException(exception);       \
+                                            destroyException(exception);                           \
+                                            throw WasmException(description);                      \
+                                          });                                                      \
   } while (0)
 
 #define CALL_WITH_CONTEXT_RETURN(_x, _context, _type, _member)                                     \
   do {                                                                                             \
     SaveRestoreContext _saved_context(static_cast<Context*>(_context));                            \
-    return static_cast<_type>(_x[0]._member);                                                      \
+    _type _return_value;                                                                           \
+    WAVM::Runtime::catchRuntimeExceptions(                                                         \
+        [&] { _return_value = static_cast<_type>(_x[0]._member); },                                \
+        [&](WAVM::Runtime::Exception* exception) {                                                 \
+          auto description = describeException(exception);                                         \
+          destroyException(exception);                                                             \
+          throw WasmException(description);                                                        \
+        });                                                                                        \
+    return _return_value;                                                                          \
   } while (0)
 
 class RootResolver : public WAVM::Runtime::Resolver, public Logger::Loggable<wasmId> {

test/extensions/wasm/test_data/Makefile

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

test/extensions/wasm/test_data/segv.cc

@@ -0,0 +1,18 @@
+// NOLINT(namespace-envoy)
+#include <string>
+
+#include "proxy_wasm_intrinsics.h"
+
+static int* badptr = nullptr;
+
+extern "C" EMSCRIPTEN_KEEPALIVE void proxy_onStart() {
+  logError("before badptr");
+  *badptr = 1;
+  logError("after badptr");
+}
+
+extern "C" EMSCRIPTEN_KEEPALIVE void proxy_onLog(uint32_t context_id) {
+  logError("before div by zero");
+  logError("divide by zero: " + std::to_string(100 / context_id));
+  logError("after div by zero");
+}