Automatically discard global effects in the rare passes that add effects (#5999)

All logging/instrumentation passes need to do this, to avoid us using stale
global effects that are too low (too high is not optimal either, but at least it
cannot cause bugs).

1 files changed, 93 insertions, 0 deletions

diff --git a/test/lit/passes/instrument-locals_effects.wast b/test/lit/passes/instrument-locals_effects.wast
new file mode 100644
index 000000000..5c0c61d06
--- /dev/null
+++ b/test/lit/passes/instrument-locals_effects.wast
@@ -0,0 +1,93 @@
+;; 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.
+
+;; Test that this instrumentation pass discards global effects, which it must do
+;; as it adds calls to imports. We can optimize below when we do not instrument,
+;; and cannot when we do.
+;;
+;; In NO_INSTRMT below we run another pass, just to prove that not every pass
+;; causes global effects to be discarded.
+
+;; RUN: foreach %s %t wasm-opt --generate-global-effects --instrument-locals --vacuum -S -o - | filecheck %s --check-prefix INSTRUMENT
+;; RUN: foreach %s %t wasm-opt --generate-global-effects --coalesce-locals   --vacuum -S -o - | filecheck %s --check-prefix NO_INSTRMT
+
+(module
+  ;; INSTRUMENT:      (type $0 (func))
+
+  ;; INSTRUMENT:      (type $1 (func (param i32 i32 i32) (result i32)))
+
+  ;; INSTRUMENT:      (type $2 (func (param i32 i32 i64) (result i64)))
+
+  ;; INSTRUMENT:      (type $3 (func (param i32 i32 f32) (result f32)))
+
+  ;; INSTRUMENT:      (type $4 (func (param i32 i32 f64) (result f64)))
+
+  ;; INSTRUMENT:      (import "env" "get_i32" (func $get_i32 (param i32 i32 i32) (result i32)))
+
+  ;; INSTRUMENT:      (import "env" "get_i64" (func $get_i64 (param i32 i32 i64) (result i64)))
+
+  ;; INSTRUMENT:      (import "env" "get_f32" (func $get_f32 (param i32 i32 f32) (result f32)))
+
+  ;; INSTRUMENT:      (import "env" "get_f64" (func $get_f64 (param i32 i32 f64) (result f64)))
+
+  ;; INSTRUMENT:      (import "env" "set_i32" (func $set_i32 (param i32 i32 i32) (result i32)))
+
+  ;; INSTRUMENT:      (import "env" "set_i64" (func $set_i64 (param i32 i32 i64) (result i64)))
+
+  ;; INSTRUMENT:      (import "env" "set_f32" (func $set_f32 (param i32 i32 f32) (result f32)))
+
+  ;; INSTRUMENT:      (import "env" "set_f64" (func $set_f64 (param i32 i32 f64) (result f64)))
+
+  ;; INSTRUMENT:      (func $past-get
+  ;; INSTRUMENT-NEXT:  (call $use-local)
+  ;; INSTRUMENT-NEXT:  (call $nop)
+  ;; INSTRUMENT-NEXT: )
+  ;; NO_INSTRMT:      (type $0 (func))
+
+  ;; NO_INSTRMT:      (func $past-get
+  ;; NO_INSTRMT-NEXT:  (nop)
+  ;; NO_INSTRMT-NEXT: )
+  (func $past-get
+    ;; The called function only sets a local, so we can vacuum it away using
+    ;; global effects. But, if we instrumented it, then it gets an import call,
+    ;; which we should not remove.
+    (call $use-local)
+    ;; If we instrument, then we discard all global effects, even of a non-
+    ;; instrumented function (we don't track individual functions), so we'll
+    ;; lose the ability to vacuum this function away as well in that case.
+    (call $nop)
+  )
+
+  ;; INSTRUMENT:      (func $use-local
+  ;; INSTRUMENT-NEXT:  (local $x i32)
+  ;; INSTRUMENT-NEXT:  (local.set $x
+  ;; INSTRUMENT-NEXT:   (call $set_i32
+  ;; INSTRUMENT-NEXT:    (i32.const 0)
+  ;; INSTRUMENT-NEXT:    (i32.const 0)
+  ;; INSTRUMENT-NEXT:    (i32.const 10)
+  ;; INSTRUMENT-NEXT:   )
+  ;; INSTRUMENT-NEXT:  )
+  ;; INSTRUMENT-NEXT: )
+  ;; NO_INSTRMT:      (func $use-local
+  ;; NO_INSTRMT-NEXT:  (local $0 i32)
+  ;; NO_INSTRMT-NEXT:  (nop)
+  ;; NO_INSTRMT-NEXT: )
+  (func $use-local
+    (local $x i32)
+    ;; This function uses a local, and will get instrumented with a call to log
+    ;; the value out.
+    (local.set $x
+      (i32.const 10)
+    )
+  )
+
+  ;; INSTRUMENT:      (func $nop
+  ;; INSTRUMENT-NEXT:  (nop)
+  ;; INSTRUMENT-NEXT: )
+  ;; NO_INSTRMT:      (func $nop
+  ;; NO_INSTRMT-NEXT:  (nop)
+  ;; NO_INSTRMT-NEXT: )
+  (func $nop
+    ;; This function does nothing.
+  )
+)