wasm-ctor-eval improvements (#1631)

*    When we eval a ctor, don't just nop the function body that no longer needs to be executed, also remove the export (as we report the ctor being evalled, and the outside will no longer call it).
*    Run the pass to remove unused global things. This can usually remove evalled ctors (unless something else happens to call them, which can't happen normally as LLVM wouldn't use a ctor in another place, but e.g. duplicate function merging might merge a ctor with another function).

13 files changed, 18 insertions, 126 deletions

diff --git a/src/tools/wasm-ctor-eval.cpp b/src/tools/wasm-ctor-eval.cpp
index b71a0356a..dee342255 100644
--- a/src/tools/wasm-ctor-eval.cpp
+++ b/src/tools/wasm-ctor-eval.cpp
@@ -345,9 +345,12 @@ void evalCtors(Module& wasm, std::vector<std::string> ctors) {
       }
       std::cerr << "  ...success on " << ctor << ".\n";
       // success, the entire function was evalled!
+      // we can nop the function (which may be used elsewhere)
+      // and remove the export
       auto* exp = wasm.getExport(ctor);
       auto* func = wasm.getFunction(exp->value);
       func->body = wasm.allocator.alloc<Nop>();
+      wasm.removeExport(exp->name);
     }
   } catch (FailToEvalException& fail) {
     // that's it, we failed to even create the instance
@@ -426,6 +429,7 @@ int main(int argc, const char* argv[]) {
     passRunner.add("dce");
     passRunner.add("merge-blocks");
     passRunner.add("vacuum");
+    passRunner.add("remove-unused-module-elements");
     passRunner.run();
   }
 
diff --git a/test/ctor-eval/bad-indirect-call2.wast.out b/test/ctor-eval/bad-indirect-call2.wast.out
index b6a50c2f5..5efde23ed 100644
--- a/test/ctor-eval/bad-indirect-call2.wast.out
+++ b/test/ctor-eval/bad-indirect-call2.wast.out
@@ -1,5 +1,4 @@
 (module
- (type $v (func))
  (type $FUNCSIG$v (func))
  (import "env" "_abort" (func $_abort))
  (table 2 2 anyfunc)
@@ -7,8 +6,8 @@
  (memory $0 256 256)
  (data (i32.const 10) "waka waka waka waka waka")
  (export "test1" (func $test1))
- (func $test1 (; 1 ;) (type $v)
-  (call_indirect (type $v)
+ (func $test1 (; 1 ;) (type $FUNCSIG$v)
+  (call_indirect (type $FUNCSIG$v)
    (i32.const 0)
   )
   (i32.store8
@@ -16,7 +15,7 @@
    (i32.const 120)
   )
  )
- (func $call-indirect (; 2 ;) (type $v)
+ (func $call-indirect (; 2 ;) (type $FUNCSIG$v)
   (i32.store8
    (i32.const 40)
    (i32.const 67)
diff --git a/test/ctor-eval/basics-flatten.wast.out b/test/ctor-eval/basics-flatten.wast.out
index b3b937c59..4273c256a 100644
--- a/test/ctor-eval/basics-flatten.wast.out
+++ b/test/ctor-eval/basics-flatten.wast.out
@@ -1,32 +1,8 @@
 (module
  (type $v (func))
- (table 1 1 anyfunc)
- (elem (i32.const 0) $call-indirect)
  (memory $0 256 256)
  (data (i32.const 10) "nas\00\00\00aka\00yzkx waka wakm\00\00\00\00\00\00C")
- (export "test1" (func $test1))
- (export "test2" (func $test2))
- (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $v)
-  (nop)
- )
- (func $test2 (; 1 ;) (type $v)
-  (nop)
- )
- (func $test3 (; 2 ;) (type $v)
-  (nop)
- )
- (func $safe-to-call (; 3 ;) (type $v)
-  (i32.store8
-   (i32.const 10)
-   (i32.const 110)
-  )
-  (i32.store8
-   (i32.const 33)
-   (i32.const 109)
-  )
- )
- (func $call-indirect (; 4 ;) (type $v)
+ (func $call-indirect (; 0 ;) (type $v)
   (i32.store8
    (i32.const 40)
    (i32.const 67)
diff --git a/test/ctor-eval/basics.wast.out b/test/ctor-eval/basics.wast.out
index 3179f7b36..185e556ec 100644
--- a/test/ctor-eval/basics.wast.out
+++ b/test/ctor-eval/basics.wast.out
@@ -1,32 +1,8 @@
 (module
  (type $v (func))
- (table 1 1 anyfunc)
- (elem (i32.const 0) $call-indirect)
  (memory $0 256 256)
  (data (i32.const 10) "nas\00\00\00aka yzkx waka wakm\00\00\00\00\00\00C")
- (export "test1" (func $test1))
- (export "test2" (func $test2))
- (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $v)
-  (nop)
- )
- (func $test2 (; 1 ;) (type $v)
-  (nop)
- )
- (func $test3 (; 2 ;) (type $v)
-  (nop)
- )
- (func $safe-to-call (; 3 ;) (type $v)
-  (i32.store8
-   (i32.const 10)
-   (i32.const 110)
-  )
-  (i32.store8
-   (i32.const 33)
-   (i32.const 109)
-  )
- )
- (func $call-indirect (; 4 ;) (type $v)
+ (func $call-indirect (; 0 ;) (type $v)
   (i32.store8
    (i32.const 40)
    (i32.const 67)
diff --git a/test/ctor-eval/imported-min.wast.out b/test/ctor-eval/imported-min.wast.out
index dd0f88841..3871caf2f 100644
--- a/test/ctor-eval/imported-min.wast.out
+++ b/test/ctor-eval/imported-min.wast.out
@@ -1,22 +1,11 @@
 (module
  (type $0 (func))
- (import "env" "STACKTOP" (global $STACKTOP$asm2wasm$import i32))
- (import "env" "STACK_MAX" (global $STACK_MAX$asm2wasm$import i32))
  (import "env" "tempDoublePtr" (global $tempDoublePtr i32))
- (global $mine (mut i32) (i32.const 1))
- (global $global0 (mut i32) (get_global $STACKTOP$asm2wasm$import))
- (global $global1 (mut i32) (get_global $STACK_MAX$asm2wasm$import))
- (global $do-not-use (mut i32) (get_global $tempDoublePtr))
  (memory $0 256 256)
  (data (i32.const 10) "wasa waka waka waka waka")
- (export "test1" (func $test1))
  (export "test2" (func $test2))
  (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $0)
-  (local $temp i32)
-  (nop)
- )
- (func $test2 (; 1 ;) (type $0)
+ (func $test2 (; 0 ;) (type $0)
   (set_global $tempDoublePtr
    (i32.const 1)
   )
@@ -25,7 +14,7 @@
    (i32.const 115)
   )
  )
- (func $test3 (; 2 ;) (type $0)
+ (func $test3 (; 1 ;) (type $0)
   (i32.store8
    (i32.const 14)
    (i32.const 115)
diff --git a/test/ctor-eval/imported.wast.out b/test/ctor-eval/imported.wast.out
index 6a7557e88..3871caf2f 100644
--- a/test/ctor-eval/imported.wast.out
+++ b/test/ctor-eval/imported.wast.out
@@ -1,22 +1,11 @@
 (module
  (type $0 (func))
- (import "env" "STACKTOP" (global $STACKTOP$asm2wasm$import i32))
- (import "env" "STACK_MAX" (global $STACK_MAX$asm2wasm$import i32))
  (import "env" "tempDoublePtr" (global $tempDoublePtr i32))
- (global $mine (mut i32) (i32.const 1))
- (global $STACKTOP (mut i32) (get_global $STACKTOP$asm2wasm$import))
- (global $STACK_MAX (mut i32) (get_global $STACK_MAX$asm2wasm$import))
- (global $do-not-use (mut i32) (get_global $tempDoublePtr))
  (memory $0 256 256)
  (data (i32.const 10) "wasa waka waka waka waka")
- (export "test1" (func $test1))
  (export "test2" (func $test2))
  (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $0)
-  (local $temp i32)
-  (nop)
- )
- (func $test2 (; 1 ;) (type $0)
+ (func $test2 (; 0 ;) (type $0)
   (set_global $tempDoublePtr
    (i32.const 1)
   )
@@ -25,7 +14,7 @@
    (i32.const 115)
   )
  )
- (func $test3 (; 2 ;) (type $0)
+ (func $test3 (; 1 ;) (type $0)
   (i32.store8
    (i32.const 14)
    (i32.const 115)
diff --git a/test/ctor-eval/imported2.wast.out b/test/ctor-eval/imported2.wast.out
index add5a1e99..e86317071 100644
--- a/test/ctor-eval/imported2.wast.out
+++ b/test/ctor-eval/imported2.wast.out
@@ -1,18 +1,11 @@
 (module
  (type $0 (func))
- (import "env" "STACKTOP" (global $STACKTOP i32))
- (import "env" "STACK_MAX" (global $STACK_MAX i32))
- (import "env" "tempDoublePtr" (global $tempDoublePtr i32))
  (global $mine (mut i32) (i32.const 1))
  (memory $0 256 256)
  (data (i32.const 10) "wasa waka waka waka waka")
- (export "test1" (func $test1))
  (export "test2" (func $test2))
  (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $0)
-  (nop)
- )
- (func $test2 (; 1 ;) (type $0)
+ (func $test2 (; 0 ;) (type $0)
   (set_global $mine
    (i32.const 2)
   )
@@ -21,7 +14,7 @@
    (i32.const 115)
   )
  )
- (func $test3 (; 2 ;) (type $0)
+ (func $test3 (; 1 ;) (type $0)
   (i32.store8
    (i32.const 14)
    (i32.const 115)
diff --git a/test/ctor-eval/imported3.wast.out b/test/ctor-eval/imported3.wast.out
index b7e9dc5a3..0cbf32cea 100644
--- a/test/ctor-eval/imported3.wast.out
+++ b/test/ctor-eval/imported3.wast.out
@@ -1,7 +1,5 @@
 (module
  (type $0 (func))
- (import "env" "tempDoublePtr" (global $tempDoublePtr i32))
- (global $mine (mut i32) (get_global $tempDoublePtr))
  (memory $0 256 256)
  (data (i32.const 10) "waka waka waka waka waka")
  (export "test1" (func $test1))
diff --git a/test/ctor-eval/indirect-call3.wast.out b/test/ctor-eval/indirect-call3.wast.out
index a4b2ac337..27351bcce 100644
--- a/test/ctor-eval/indirect-call3.wast.out
+++ b/test/ctor-eval/indirect-call3.wast.out
@@ -1,17 +1,10 @@
 (module
- (type $v (func))
  (type $FUNCSIG$v (func))
  (import "env" "tableBase" (global $tableBase i32))
  (import "env" "_abort" (func $_abort))
- (table 2 2 anyfunc)
- (elem (get_global $tableBase) $_abort $call-indirect)
  (memory $0 256 256)
  (data (i32.const 10) "waka waka xaka waka waka\00\00\00\00\00\00C")
- (export "test1" (func $test1))
- (func $test1 (; 1 ;) (type $v)
-  (nop)
- )
- (func $call-indirect (; 2 ;) (type $v)
+ (func $call-indirect (; 1 ;) (type $FUNCSIG$v)
   (i32.store8
    (i32.const 40)
    (i32.const 67)
diff --git a/test/ctor-eval/just_some.wast.out b/test/ctor-eval/just_some.wast.out
index c44e6a9df..b7a1aa2be 100644
--- a/test/ctor-eval/just_some.wast.out
+++ b/test/ctor-eval/just_some.wast.out
@@ -2,16 +2,12 @@
  (type $0 (func))
  (memory $0 256 256)
  (data (i32.const 10) "wasa waka waka waka waka")
- (export "test1" (func $test1))
  (export "test2" (func $test2))
  (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $0)
-  (nop)
- )
- (func $test2 (; 1 ;) (type $0)
+ (func $test2 (; 0 ;) (type $0)
   (unreachable)
  )
- (func $test3 (; 2 ;) (type $0)
+ (func $test3 (; 1 ;) (type $0)
   (i32.store8
    (i32.const 13)
    (i32.const 113)
diff --git a/test/ctor-eval/unsafe_store.wast.out b/test/ctor-eval/unsafe_store.wast.out
index 36f3b74bd..e51bd298d 100644
--- a/test/ctor-eval/unsafe_store.wast.out
+++ b/test/ctor-eval/unsafe_store.wast.out
@@ -1,11 +1,4 @@
 (module
- (type $0 (func))
- (memory $0 256 256)
- (data (i32.const 9) "mwaka waka waka waka waka")
- (export "test1" (func $test1))
  (export "test2" (func $test2))
  (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $0)
-  (nop)
- )
 )
diff --git a/test/ctor-eval/unsafe_store2.wast.out b/test/ctor-eval/unsafe_store2.wast.out
index a0d34e8b4..e51bd298d 100644
--- a/test/ctor-eval/unsafe_store2.wast.out
+++ b/test/ctor-eval/unsafe_store2.wast.out
@@ -1,11 +1,4 @@
 (module
- (type $0 (func))
- (memory $0 256 256)
- (data (i32.const 10) "waka waka waka waka wakam")
- (export "test1" (func $test1))
  (export "test2" (func $test2))
  (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $0)
-  (nop)
- )
 )
diff --git a/test/ctor-eval/unsafe_store3.wast.out b/test/ctor-eval/unsafe_store3.wast.out
index 189f830e7..e51bd298d 100644
--- a/test/ctor-eval/unsafe_store3.wast.out
+++ b/test/ctor-eval/unsafe_store3.wast.out
@@ -1,11 +1,4 @@
 (module
- (type $0 (func))
- (memory $0 256 256)
- (data (i32.const 10) "waka waka waka waka wakm")
- (export "test1" (func $test1))
  (export "test2" (func $test2))
  (export "test3" (func $test3))
- (func $test1 (; 0 ;) (type $0)
-  (nop)
- )
 )