[wasm] Stage exception handling

This was staged through a back-merge in v8.9. Also stage it for the
upcoming v9.0 release.

R=clemensb@chromium.org

Bug: v8:8091
Change-Id: Ib9e8c33ca258c8b9e407fbcca5db9f0227b558b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718150Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73019}

src/wasm/baseline/liftoff-compiler.cc

@@ -375,6 +375,12 @@ void CheckBailoutAllowed(LiftoffBailoutReason reason, const char* detail,
     return;
   }
 
+  // TODO(v8:8091): Implement exception handling in Liftoff.
+  if (reason == kExceptionHandling) {
+    DCHECK(env->enabled_features.has_eh());
+    return;
+  }
+
   // Otherwise, bailout is not allowed.
   FATAL("Liftoff bailout should not happen. Cause: %s\n", detail);
 }

src/wasm/wasm-feature-flags.h

@@ -10,11 +10,6 @@
 
 // Experimental features (disabled by default).
 #define FOREACH_WASM_EXPERIMENTAL_FEATURE_FLAG(V) /*     (force 80 columns) */ \
-  /* Exception handling proposal. */                                           \
-  /* https://github.com/WebAssembly/exception-handling */                      \
-  /* V8 side owner: thibaudm */                                                \
-  V(eh, "exception handling opcodes", false)                                   \
-                                                                               \
   /* No official proposal (yet?). */                                           \
   /* V8 side owner: clemensb */                                                \
   V(compilation_hints, "compilation hints section", false)                     \
@@ -44,6 +39,12 @@
 // be shipped with enough lead time to the next branch to allow for
 // stabilization.
 #define FOREACH_WASM_STAGING_FEATURE_FLAG(V) /*          (force 80 columns) */ \
+  /* Exception handling proposal. */                                           \
+  /* https://github.com/WebAssembly/exception-handling */                      \
+  /* V8 side owner: thibaudm */                                                \
+  /* Staged in v8.9 */                                                         \
+  V(eh, "exception handling opcodes", false)                                   \
+                                                                               \
   /* Reference Types, a.k.a. reftypes proposal. */                             \
   /* https://github.com/WebAssembly/reference-types */                         \
   /* V8 side owner: ahaas */                                                   \