Add event section (#2151)

This adds support for the event and the event section, as specified in
https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md#changes-to-the-binary-model.

Wasm events are features that suspend the current execution and transfer
the control flow to a corresponding handler. Currently the only
supported event kind is exceptions.

For events, this includes support for
- Binary file reading/writing
- Wast file reading/writing
- Binaryen.js API
- Fuzzer
- Validation
- Metadce
- Passes: metrics, minify-imports-and-exports,
  remove-unused-module-elements

1 files changed, 43 insertions, 0 deletions

diff --git a/test/spec/events.wast b/test/spec/events.wast
new file mode 100644
index 000000000..80a6b11fe
--- /dev/null
+++ b/test/spec/events.wast
@@ -0,0 +1,43 @@
+;; Test events
+
+(module
+  (event (attr 0) (param i32))
+  (event $e (attr 0) (param i32 f32))
+
+  (event $e-params0 (attr 0) (param i32 f32))
+  (event $e-params1 (attr 0) (param i32) (param f32))
+
+  (event $e-export (export "ex0") (attr 0) (param i32))
+  (event $e-import (import "env" "im0") (attr 0) (param i32))
+
+  (import "env" "im1" (event (attr 0) (param i32 f32)))
+  (export "ex1" (event $e))
+)
+
+(assert_invalid
+  (module (event $e (attr 0) (param i32) (result i32)))
+   "Event type's result type should be none"
+)
+
+(assert_invalid
+  (module (event $e (attr 0)))
+  "There should be 1 or more values in an event type"
+)
+
+(assert_invalid
+  (module (event $e (attr 1) (param i32)))
+   "Currently only attribute 0 is supported"
+)
+
+(assert_invalid
+  (module (event $e (attr 0) (param except_ref)))
+  "Values in an event should have integer or float type"
+)
+
+(assert_invalid
+  (module
+    (type $t (param i32))
+    (event $e (attr 0) (type $t) (param i32 f32))
+    "type and param don't match"
+  )
+)