Fix GUFA on calls to function refs in open world (#7135)

In open world we must assume that a funcref that escapes to the outside
might be called.

3 files changed, 76 insertions, 2 deletions

diff --git a/test/lit/passes/gufa-closed-open.wast b/test/lit/passes/gufa-closed-open.wast
new file mode 100644
index 000000000..47add9df5
--- /dev/null
+++ b/test/lit/passes/gufa-closed-open.wast
@@ -0,0 +1,68 @@
+;; 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 --check-prefix OPEND
+;; RUN: foreach %s %t wasm-opt -all --gufa --closed-world -S -o - | filecheck %s --check-prefix CLOSE
+
+;; Compare behavior on closed and open world. In open world we must assume that
+;; funcrefs, for example, can be called from outside.
+
+(module
+ ;; OPEND:      (type $0 (func (param funcref)))
+
+ ;; OPEND:      (type $1 (func))
+
+ ;; OPEND:      (type $2 (func (param i32)))
+
+ ;; OPEND:      (import "fuzzing-support" "call-ref-catch" (func $external-caller (type $0) (param funcref)))
+ ;; CLOSE:      (type $0 (func (param funcref)))
+
+ ;; CLOSE:      (type $1 (func))
+
+ ;; CLOSE:      (type $2 (func (param i32)))
+
+ ;; CLOSE:      (import "fuzzing-support" "call-ref-catch" (func $external-caller (type $0) (param funcref)))
+ (import "fuzzing-support" "call-ref-catch" (func $external-caller (param funcref)))
+
+ ;; OPEND:      (elem declare func $func)
+
+ ;; OPEND:      (export "call-import" (func $call-import))
+
+ ;; OPEND:      (func $call-import (type $1)
+ ;; OPEND-NEXT:  (call $external-caller
+ ;; OPEND-NEXT:   (ref.func $func)
+ ;; OPEND-NEXT:  )
+ ;; OPEND-NEXT: )
+ ;; CLOSE:      (elem declare func $func)
+
+ ;; CLOSE:      (export "call-import" (func $call-import))
+
+ ;; CLOSE:      (func $call-import (type $1)
+ ;; CLOSE-NEXT:  (call $external-caller
+ ;; CLOSE-NEXT:   (ref.func $func)
+ ;; CLOSE-NEXT:  )
+ ;; CLOSE-NEXT: )
+ (func $call-import (export "call-import")
+  ;; Send a reference to $func to the outside, which may call it.
+  (call $external-caller
+   (ref.func $func)
+  )
+ )
+
+ ;; OPEND:      (func $func (type $2) (param $0 i32)
+ ;; OPEND-NEXT:  (drop
+ ;; OPEND-NEXT:   (local.get $0)
+ ;; OPEND-NEXT:  )
+ ;; OPEND-NEXT: )
+ ;; CLOSE:      (func $func (type $2) (param $0 i32)
+ ;; CLOSE-NEXT:  (drop
+ ;; CLOSE-NEXT:   (unreachable)
+ ;; CLOSE-NEXT:  )
+ ;; CLOSE-NEXT: )
+ (func $func (param $0 i32)
+  ;; This is called from the outside, so this is not dead code, and nothing
+  ;; should change here in open world. In closed world, this can become an
+  ;; unreachable, since nothing can call it.
+  (drop
+   (local.get $0)
+  )
+ )
+)
diff --git a/test/lit/passes/gufa-refs.wast b/test/lit/passes/gufa-refs.wast
index 9772745bc..80fd32386 100644
--- a/test/lit/passes/gufa-refs.wast
+++ b/test/lit/passes/gufa-refs.wast
@@ -1,5 +1,8 @@
 ;; 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
+;; RUN: foreach %s %t wasm-opt -all --gufa --closed-world -S -o - | filecheck %s
+
+;; Closed-world is applied here to avoid treating all ref.funcs as callable
+;; from outside (and this is the more important mode to test on).
 
 (module
   ;; CHECK:      (type $struct (struct))
diff --git a/test/lit/passes/gufa.wast b/test/lit/passes/gufa.wast
index fcb60310a..721c27eeb 100644
--- a/test/lit/passes/gufa.wast
+++ b/test/lit/passes/gufa.wast
@@ -1,5 +1,8 @@
 ;; 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
+;; RUN: foreach %s %t wasm-opt -all --gufa --closed-world -S -o - | filecheck %s
+
+;; Closed-world is applied here to avoid treating all ref.funcs as callable
+;; from outside (and this is the more important mode to test on).
 
 (module
   ;; CHECK:      (type $0 (func (result i32)))