Properly use pass options in nested pass runners (up to -O1) (#5351)

This fixes a TODO.

There is a runtime cost to this in higher opt levels, as passing through -O3
makes nested optimization work take longer. But it can lead to better results.
For now, this PR moves us from 0 before to a maximum of 1, as a compromise.
1 does not regress compile times, but there may be further benefits to allowing
2 and 3 in the future.

Also fix a fuzzer bug that becomes uncovered by tihs PR: Now that we actually
optimize in simplify-globals, we need to handle the case of the optimizer there
seeing a call with the effects of writing to a global (we had an assert on that
never happening, but with function effects that can happen, and so a GlobalSet
is not the only thing that can set a global).

Aside from the opt and shrink levels this passes through all other options,
like trapsNeverHappen.

1 files changed, 91 insertions, 0 deletions

diff --git a/test/lit/passes/simplify-globals_func-effects.wast b/test/lit/passes/simplify-globals_func-effects.wast
new file mode 100644
index 000000000..8257c5ce7
--- /dev/null
+++ b/test/lit/passes/simplify-globals_func-effects.wast
@@ -0,0 +1,91 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: foreach %s %t wasm-opt --generate-global-effects --simplify-globals -S -o - | filecheck %s
+
+;; Compute function effects and then simplify globals. We must handle the case
+;; of an expression that is not a global.set that sets a global - a function
+;; whose effects we've computed to include some sets to globals.
+
+(module
+ ;; CHECK:      (type $none_=>_none (func))
+
+ ;; CHECK:      (global $A (mut i32) (i32.const 10))
+ (global $A (mut i32) (i32.const 10))
+
+ ;; CHECK:      (global $B i32 (i32.const 20))
+ (global $B (mut i32) (i32.const 20))
+
+ ;; CHECK:      (global $C (mut i32) (i32.const 30))
+ (global $C (mut i32) (i32.const 30))
+
+ ;; CHECK:      (func $set
+ ;; CHECK-NEXT:  (global.set $A
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $set
+  (global.set $A
+   (i32.const 0)
+  )
+ )
+
+ ;; CHECK:      (func $test
+ ;; CHECK-NEXT:  (global.set $A
+ ;; CHECK-NEXT:   (i32.const 11)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (global.set $C
+ ;; CHECK-NEXT:   (i32.const 33)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:   (i32.const 11)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:   (i32.const 20)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:   (i32.const 33)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (call $set)
+ ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:   (global.get $A)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:   (i32.const 20)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:   (i32.const 33)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $test
+  (global.set $A
+   (i32.const 11)
+  )
+  (global.set $C
+   (i32.const 33)
+  )
+  ;; We can infer $A here since we see the write to it, above.
+  (drop
+   (global.get $A)
+  )
+  ;; We can infer $B since we'll prove it is immutable.
+  (drop
+   (global.get $B)
+  )
+  ;; We can infer $C here since we see the write to it, above.
+  (drop
+   (global.get $C)
+  )
+  ;; This call sets $A. After the call we can no longer infer $A, but we can
+  ;; still infer the others.
+  (call $set)
+  (drop
+   (global.get $A)
+  )
+  (drop
+   (global.get $B)
+  )
+  (drop
+   (global.get $C)
+  )
+ )
+)