WIP: wasm oob trap handling experiments

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 77beac12a2b984272e9408a5cf4f11d29c874235..a136f06830d564cae86aff746b5c02c71fbc537c 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -381,6 +381,7 @@ class RelocInfo {
     WASM_MEMORY_REFERENCE,
     WASM_GLOBAL_REFERENCE,
     WASM_MEMORY_SIZE_REFERENCE,
+    WASM_TRAP_LANDING,
     CELL,
 
     // Everything after runtime_entry (inclusive) is not GC'ed.
@@ -521,6 +522,9 @@ class RelocInfo {
   static inline bool IsWasmGlobalReference(Mode mode) {
     return mode == WASM_GLOBAL_REFERENCE;
   }
+  static inline bool IsWasmTrapLanding(Mode mode) {
+    return mode == WASM_TRAP_LANDING;
+  }
   static inline int ModeMask(Mode mode) { return 1 << mode; }
 
   // Accessors