[Exceptions] Finish interpreter + optimizer support for try_table. (#6814)

* Add interpreter support for exnref values.
* Fix optimization passes to support try_table.
* Enable the interpreter (but not in V8, see code) on exceptions.

1 files changed, 60 insertions, 0 deletions

diff --git a/test/lit/passes/gufa-eh.wast b/test/lit/passes/gufa-eh.wast
new file mode 100644
index 000000000..79265a318
--- /dev/null
+++ b/test/lit/passes/gufa-eh.wast
@@ -0,0 +1,60 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: foreach %s %t wasm-opt -all --gufa -S -o - | filecheck %s
+
+(module
+  ;; CHECK:      (type $0 (func (param i32)))
+
+  ;; CHECK:      (type $1 (func (result i32)))
+
+  ;; CHECK:      (type $2 (func))
+
+  ;; CHECK:      (tag $e (param i32))
+  (tag $e (param i32))
+
+  ;; CHECK:      (func $try_table-target-block-is-not-unreachable (type $1) (result i32)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (block $catch (result i32)
+  ;; CHECK-NEXT:    (try_table (catch $e $catch)
+  ;; CHECK-NEXT:     (throw $e
+  ;; CHECK-NEXT:      (i32.const 0)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (i32.const 0)
+  ;; CHECK-NEXT: )
+  (func $try_table-target-block-is-not-unreachable (result i32)
+    ;; Ensure that try_table connects caught tags with their branch targets.
+    (block $catch (result i32)
+      (try_table (catch $e $catch)
+        (throw $e (i32.const 0))
+      )
+    )
+  )
+
+  ;; CHECK:      (func $try_table-materializes-exnref (type $2)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (block $catch (result exnref)
+  ;; CHECK-NEXT:    (try_table (catch_all_ref $catch)
+  ;; CHECK-NEXT:     (throw $e
+  ;; CHECK-NEXT:      (i32.const 0)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $try_table-materializes-exnref
+    ;; Ensure that catch_all_ref materializes a non-null exnref value. If we do
+    ;; not connect a non-null exnref value to the branch target, GUFA will think
+    ;; no value can possibly get out of that block, and will insert an
+    ;; unreachable instruction after the block.
+    (drop
+      (block $catch (result exnref)
+        (try_table (catch_all_ref $catch)
+          (throw $e (i32.const 0))
+        )
+      )
+    )
+  )
+)