4 files changed, 100 insertions, 65 deletions
diff --git a/test/lit/help/wasm-opt.test b/test/lit/help/wasm-opt.test
index fc33fce8d..8732f5e27 100644
--- a/test/lit/help/wasm-opt.test
+++ b/test/lit/help/wasm-opt.test
@@ -467,6 +467,8 @@
 ;; CHECK-NEXT:   --stack-check                                 enforce limits on llvm's
 ;; CHECK-NEXT:                                                 __stack_pointer global
 ;; CHECK-NEXT:
+;; CHECK-NEXT:   --string-gathering                            gathers wasm strings to globals
+;; CHECK-NEXT:
 ;; CHECK-NEXT:   --strip                                       deprecated; same as strip-debug
 ;; CHECK-NEXT:
 ;; CHECK-NEXT:   --strip-debug                                 strip debug info (including the
diff --git a/test/lit/help/wasm2js.test b/test/lit/help/wasm2js.test
index 7db564101..40d608857 100644
--- a/test/lit/help/wasm2js.test
+++ b/test/lit/help/wasm2js.test
@@ -426,6 +426,8 @@
 ;; CHECK-NEXT:   --stack-check                                 enforce limits on llvm's
 ;; CHECK-NEXT:                                                 __stack_pointer global
 ;; CHECK-NEXT:
+;; CHECK-NEXT:   --string-gathering                            gathers wasm strings to globals
+;; CHECK-NEXT:
 ;; CHECK-NEXT:   --strip                                       deprecated; same as strip-debug
 ;; CHECK-NEXT:
 ;; CHECK-NEXT:   --strip-debug                                 strip debug info (including the
diff --git a/test/lit/passes/simplify-globals-strings.wast b/test/lit/passes/simplify-globals-strings.wast
deleted file mode 100644
index 813e2964c..000000000
--- a/test/lit/passes/simplify-globals-strings.wast
+++ /dev/null
@@ -1,65 +0,0 @@
-;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
-;; NOTE: This test was ported using port_passes_tests_to_lit.py and could be cleaned up.
-
-;; We do not "inline" strings from globals, as that might cause more
-;; allocations to happen. TODO if VMs optimize that, remove this
-
-;; RUN: foreach %s %t wasm-opt --simplify-globals -all -S -o - | filecheck %s
-
-;; Also test with -O3 --gufa to see that no other pass does this kind of thing,
-;; as extra coverage.
-
-;; RUN: foreach %s %t wasm-opt -O3 --gufa         -all -S -o - | filecheck %s --check-prefix=O3GUF
-
-(module
-  ;; CHECK:      (type $0 (func (result anyref)))
-
-  ;; CHECK:      (global $string stringref (string.const "one"))
-  ;; O3GUF:      (type $0 (func (result anyref)))
-
-  ;; O3GUF:      (global $string (ref string) (string.const "one"))
-  (global $string stringref (string.const "one"))
-
-  ;; CHECK:      (global $string-mut (mut stringref) (string.const "two"))
-  ;; O3GUF:      (global $string-mut (mut (ref string)) (string.const "two"))
-  (global $string-mut (mut stringref) (string.const "two"))
-
-  ;; CHECK:      (export "global" (func $global))
-  ;; O3GUF:      (export "global" (func $global))
-  (export "global" (func $global))
-
-  ;; CHECK:      (export "written" (func $written))
-  ;; O3GUF:      (export "written" (func $written))
-  (export "written" (func $written))
-
-  ;; CHECK:      (func $global (type $0) (result anyref)
-  ;; CHECK-NEXT:  (global.get $string)
-  ;; CHECK-NEXT: )
-  ;; O3GUF:      (func $global (type $0) (result anyref)
-  ;; O3GUF-NEXT:  (global.get $string)
-  ;; O3GUF-NEXT: )
-  (func $global (result anyref)
-    ;; This should not turn into "one".
-    (global.get $string)
-  )
-
-  ;; CHECK:      (func $written (type $0) (result anyref)
-  ;; CHECK-NEXT:  (global.set $string-mut
-  ;; CHECK-NEXT:   (string.const "three")
-  ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (global.get $string-mut)
-  ;; CHECK-NEXT: )
-  ;; O3GUF:      (func $written (type $0) (result anyref)
-  ;; O3GUF-NEXT:  (global.set $string-mut
-  ;; O3GUF-NEXT:   (string.const "three")
-  ;; O3GUF-NEXT:  )
-  ;; O3GUF-NEXT:  (global.get $string-mut)
-  ;; O3GUF-NEXT: )
-  (func $written (result anyref)
-    (global.set $string-mut
-      (string.const "three")
-    )
-    ;; This should not turn into "three".
-    (global.get $string-mut)
-  )
-)
diff --git a/test/lit/passes/string-gathering.wast b/test/lit/passes/string-gathering.wast
new file mode 100644
index 000000000..21fe358a3
--- /dev/null
+++ b/test/lit/passes/string-gathering.wast
@@ -0,0 +1,96 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: foreach %s %t wasm-opt --string-gathering -all -S -o - | filecheck %s
+
+;; All the strings should be collected into globals and used from there. They
+;; should also be sorted deterministically (alphabetically).
+
+(module
+  ;; Note that $global will be reused: no new global will be added for "foo".
+  ;; $global2 almost can, but it has the wrong type, so it won't.
+
+  ;; CHECK:      (type $0 (func))
+
+  ;; CHECK:      (global $string.const_bar (ref string) (string.const "bar"))
+
+  ;; CHECK:      (global $string.const_other (ref string) (string.const "other"))
+
+  ;; CHECK:      (global $global (ref string) (string.const "foo"))
+  (global $global (ref string) (string.const "foo"))
+
+  ;; CHECK:      (global $global2 stringref (global.get $string.const_bar))
+  (global $global2 (ref null string) (string.const "bar"))
+
+  ;; CHECK:      (func $a (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (global.get $string.const_bar)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (global.get $global)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $a
+    (drop
+      (string.const "bar")
+    )
+    (drop
+      (string.const "foo")
+    )
+  )
+
+  ;; CHECK:      (func $b (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (global.get $string.const_bar)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (global.get $string.const_other)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (global.get $global)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (global.get $global2)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $b
+    (drop
+      (string.const "bar")
+    )
+    (drop
+      (string.const "other")
+    )
+    ;; Existing global.gets are not modified (but after this pass,
+    ;; SimplifyGlobals could help; though in practice the globals would have
+    ;; been propagated here anyhow).
+    (drop
+      (global.get $global)
+    )
+    (drop
+      (global.get $global2)
+    )
+  )
+)
+
+;; Multiple possible reusable globals. Also test ignoring of imports.
+(module
+  ;; CHECK:      (import "a" "b" (global $import (ref string)))
+  (import "a" "b" (global $import (ref string)))
+
+  ;; CHECK:      (global $global1 (ref string) (string.const "foo"))
+  (global $global1 (ref string) (string.const "foo"))
+
+  ;; CHECK:      (global $global2 (ref string) (global.get $global1))
+  (global $global2 (ref string) (string.const "foo"))
+
+  ;; CHECK:      (global $global3 (ref string) (global.get $global1))
+  (global $global3 (ref string) (string.const "foo"))
+
+  ;; CHECK:      (global $global4 (ref string) (string.const "bar"))
+  (global $global4 (ref string) (string.const "bar"))
+
+  ;; CHECK:      (global $global5 (ref string) (global.get $global4))
+  (global $global5 (ref string) (string.const "bar"))
+
+  ;; CHECK:      (global $global6 (ref string) (global.get $global4))
+  (global $global6 (ref string) (string.const "bar"))
+)